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1
Derrat, Hanan S. "Organic and metal organic cationic DNA intercalators based on DPPZ analogues." Thesis, University of Sheffield, 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.574605.
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New metal complex derivatives of tppz containing cationic "diquat" sites have been synthesized and characterized. Their interaction with DNA has also been explored .. Water-soluble organic cationic derivatives of the dppz ligand with a variety of functional groups and number of aromatic rings in the phenazine region have also been synthesised and characterized. These systems were synthesized with the aim of modulating the energy of the internal charge transfer excited state of the parent cation. The interactions of the new organic diquaterary salts of dppz with ON A have been studied. Metal complexes containing dppz ligands that are the free base analogues of the cationic systems have also been synthesized and their interaction with DNA has also been investigated.
2
Dyer, Joanne. "Designing infrared probes of DNA based on rhenium tricarbonyl DPPZ complexes." Thesis, University of Nottingham, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.289455.
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Madureira, João Paulo Lopes. "Complexos de ruténio com ligandos politioéteres e/ou polipiridílicos : síntese, caracterização estrutural e interacção com o ADN." Doctoral thesis, Universidade de Aveiro, 2005. http://hdl.handle.net/10773/15264.
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Doutoramento em QuímicaNesta tese são apresentados perto de quatro dezenas de novos complexos de ruténio(II), em cuja esfera de coordenação estão simultaneamente presentes um politioéter macrocíclico e um ligando polipiridílico. Os complexos sintetizados possuem as fórmulas genéricas [Ru([9]anoS3)(N-N)Cl]+ ou [Ru([12]anoS4)(N-N)]2+, em que [9]anoS3 é 1,4,7-tritiociclononano, [12]anoS4 é 1,4,7,10-tetratiociclododecano e N-N representa um ligando polipiridílico. Estes últimos foram seleccionados entre ligandos disponíveis comercialmente, de síntese conhecida da literatura, ou ainda entre novos derivados de dipirido[3,2-a:2’,3’-c]fenazina (ddpz). Os novos derivados de dppz foram concebidos com base numa das seguintes alternativas: i) expansão directa da superfície aromática; ii) acoplamento formal de pteridinas a uma unidade fenantrolina e iii) formação de ligações covalentes C-C entre dppz e grupos poliaromáticos. Foram também sintetizados duas dezenas de complexos de ruténio(II) em cuja esfera de coordenação se incluem macrociclos do tipo politioéter ou poliamina e variados ligandos monodentados, tais como halogenetos, dmso, MeCN, ou ligandos de azoto monocoordenados, como imidazol, indazol ou pirazol. Os diversos ligandos e complexos foram caracterizados por numerosas técnicas: infravermelho, Raman, RMN, absorção molecular, luminescência, espectrometria de massa (ES, FAB, EI), voltametria linear ou cíclica, espectroelectroquímica de UV/Vis/NIR ou de EPR, condutimetria, difracção de raios-X, microscopia electrónica de varrimento, ou análises elementares, para além de terem sido realizados cálculos teóricos auxiliares. Foi também estudado o comportamento em meio aquoso de alguns dos complexos sintetizados, assim como foi testada a capacidade de alguns dos complexos com ligandos polipiridílicos em interactuarem com o ADN. Para isso foram realizados ensaios de denaturação térmica, titulações de UV/Vis e estudos de luminescência em estado estacionário.
Nearly forty new ruthenium(II) complexes have been synthesised, with both polythioether macrocycles and polypyridyls present on the coordination sphere. The synthesised complexes have the general formula [Ru([9]aneS3)(N-N)Cl]+ or [Ru([12]aneS4)(N-N)]2+, where [9]aneS3, [12]aneS4, and N-N represents 1,4,7-trithiacyclononane, 1,4,7,10-tetrathiacyclododecane, and a polypyridyl ligand, respectively. N-N ligands have been selected from commercially available products, literature known compounds, and dipyridophenazine (dppz) new ligands, presented on this thesis. The new dipyridophenazine derivatives were designed with three different strategies: i) direct aromatic surface expansion; ii) pteridine formal coupling to a phenanthroline unit; and iii) C-C covalent bond formation between dppz and polyaromatic groups. Twenty ruthenium(II) complexes with a coordination sphere composed of a polythioether or polyamine macrocycle and several monodentate ligands (ex: halogens, dmso, MeCN and nitrogen heterocyles, as imidazole, indazole or pyrazole) have also been prepared. The ligands and complexes have been characterised by several techniques, namely: infrared, Raman, NMR, UV/Vis, luminescence, mass spectrometry (EI, ES, FAB), cyclic or linear voltammetry, UV/Vis/NIR and EPR spectro-electrochemistry, conductivity, X-ray diffraction, SEM, micro-analysis and theoretical calculations. Some of the complexes have been studied on aqueous or organic solutions in order to evaluate their reactivity and determine their formula on that media. Several polythioether-polypyridyl ruthenium complexes have been tested in order to evaluate theirs DNA interaction capability. The studies were conducted by UV/Vis titration, steady-state luminescence and thermal denaturation.
4
Ergun, Seza. "Structural And Functional Investigation Of The Interaction Of Agomelatine With Model Membranes." Master's thesis, METU, 2012. http://etd.lib.metu.edu.tr/upload/12614997/index.pdf.
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Depression is one of the most commonly seen psychiatric diseases in the population
in recent years. Treatment of depression is mainly carried out by psychiatric drugs. In
the past few years, agomelatine which is released to the market with a trade name,
Valdoxane, has been thought to have far less side effects due to its non-addictive
nature, not having trouble when the drug is quitted, and also due to its property of
binding only to the specific receptor that the drug interacts with. The action
mechanism of agomelatine on the membrane structure has not been clarified yet, for
instance, no study has been found in the literature about the interaction of agomelatin
with the lipids of biological membranes. In this current study, the interaction of
agomelatine with the model membranes of dipalmitoylphosphatidylcholine (DPPC),
dipalmitoylphosphatidylgylcerol (DPPG) and sphingomyelin (SM) is examined by
Fourier transform infrared spectroscopy (FTIR) and Differential scanning
calorimetry (DSC).
DSC and FTIR studies show that, agomelatine shifts the phase transition temperature
of DPPC and DPPG multilamellar membrane to the lower degrees, however, it shifts
the phase transition temperature of SM membrane to the higher degrees.
Agomelatine addition increases the lipid order of the DPPC and SM liposome,
whereas, it decreases the lipid order of DPPG liposome. Moreover this drug
enhances the membrane fluidity among all types of liposome studied. The increase of
v
lipid order and increase of fluidity at DPPC and SM liposome indicates domain
formation upon drug addition (Vest et al., 2004). This was also confirmed by DSC
studies.
Agomelatine enhances H bonding capacity of all types of liposomes have been
studied. However it has different effects on glycerol backbones of the DPPC and
DPPG liposomes. At low agomelatine concentrations the increase in the frequency
values indicates a decrease in the hydrogen bonding capacity of the glycerol skeleton
of DPPC. In contrast, at high concentrations of agomelatine, a decrease in the
frequency values was observed as an indicator of the enhancement of the hydrogen
bonding capacity. So it enhances H-bonding capacity at gel phase but lowers it at
liquid chrystalline phases. A progressive decreases in Tm was observed at DPPG and
DPPC liposomes where it increased the Tm at SM. The pretransition peak is
abolished and the Tm peak becomes broad, indicating a larger perturbation to the
membrane. These observations indicate the possible interaction of agomelatine with
the head group as well. The shoulder seen at the thermograms of DPPC and DPPC
liposomes at high doses may indicate the lateral phase separation in to drug-rich and
drug-poor domains (D&rsquoSouza et al., 2009). These results may indicate that agomelatine is partially buried in the hydrocarbon core of the bilayer, interacting primarily with the C2-C8 methylene region of the hydrocarbon chains. All these results highlight the fact that agomelatine interacts around the head group in such a manner that it destabilizes the membrane architecture to a large extent.
5
Cafe, Peter F. "Towards reliable contacts of molecular electronic devices to gold electrodes." Thesis, The University of Sydney, 2008. http://hdl.handle.net/2123/3870.
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SYNOPSIS OF THIS THESIS The aim of this thesis is to more fully understand and explain the binding mechanism of organic molecules to the Au(111) surface and to explore the conduction of such molecules. It consists of five discreet chapters connected to each other by the central theme of “The Single Molecule Device: Conductance and Binding”. There is a deliberate concentration on azine linkers, in particular those with a 1,10-phenanthroline-type bidentate configuration at each end. This linker unit is called a “molecular alligator clip” and is investigated as an alternative to the thiol linker unit more commonly used. Chapter 1 places the work in the broad context of Molecular Electronics and establishes the need for this research. In Chapter 2 the multiple break-junction technique (using a Scanning Tunnelling Microscope or similar device) was used to investigate the conductance of various molecules with azine linkers. A major finding of those experiments is that solvent interactions are a key factor in the conductance signal of particular molecules. Some solvents interfere with the molecule’s interaction with and attachment to the gold electrodes. One indicator of the degree of this interference is the extent of the enhancement or otherwise of the gold quantized conduction peak at 1.0 G0. Below 1.0 G0 a broad range for which the molecule enhances conduction indicates that solvent interactions contribute to a variety of structures which could bridge the electrodes, each with their own specific conductance value. The use of histograms with a Log10 scale for conductance proved useful for observing broad range features. vi Another factor which affects the conductance signal is the geometric alignment of the molecule (or the molecule-solvent structure) to the gold electrode, and the molecular alignment is explored in Chapters 3 for 1,10-phenanthroline (PHEN) and Chapter 4 for thiols. In Chapter 3 STM images, electrochemistry, and Density Functional Theory (DFT) are used to determine 1,10-phenanthroline (PHEN) structures on the Au(111) surface. It is established that PHEN binds in two modes, a physisorbed state and a chemisorbed state. The chemisorbed state is more stable and involves the extraction of gold from the bulk to form adatom-PHEN entities which are highly mobile on the gold surface. Surface pitting is viewed as evidential of the formation of the adatom-molecule entities. DFT calculations in this chapter were performed by Ante Bilic and Jeffery Reimers. The conclusions to Chapter 3 implicate the adatom as a binding mode of thiols to gold and this is explored in Chapter 4 by a timely review of nascent research in the field. The adatom motif is identified as the major binding structure for thiol terminated molecules to gold, using the explanation of surface pitting in Chapter 3 as major evidence and substantiated by emergent literature, both experimental and theoretical. Furthermore, the effect of this binding mode on conductance is explored and structures relevant to the break-junction experiment of Chapter 2 are identified and their conductance values compared. Finally, as a result of researching extensive reports of molecular conductance values, and having attempted the same, a simple method for predicting the conductance of single molecules is presented based upon the tunneling conductance formula.
6
Cafe, Peter F. "Towards reliable contacts of molecular electronic devices to gold electrodes." University of Sydney, 2008. http://hdl.handle.net/2123/3870.
Full textAbstract:
PhDSYNOPSIS OF THIS THESIS The aim of this thesis is to more fully understand and explain the binding mechanism of organic molecules to the Au(111) surface and to explore the conduction of such molecules. It consists of five discreet chapters connected to each other by the central theme of “The Single Molecule Device: Conductance and Binding”. There is a deliberate concentration on azine linkers, in particular those with a 1,10-phenanthroline-type bidentate configuration at each end. This linker unit is called a “molecular alligator clip” and is investigated as an alternative to the thiol linker unit more commonly used. Chapter 1 places the work in the broad context of Molecular Electronics and establishes the need for this research. In Chapter 2 the multiple break-junction technique (using a Scanning Tunnelling Microscope or similar device) was used to investigate the conductance of various molecules with azine linkers. A major finding of those experiments is that solvent interactions are a key factor in the conductance signal of particular molecules. Some solvents interfere with the molecule’s interaction with and attachment to the gold electrodes. One indicator of the degree of this interference is the extent of the enhancement or otherwise of the gold quantized conduction peak at 1.0 G0. Below 1.0 G0 a broad range for which the molecule enhances conduction indicates that solvent interactions contribute to a variety of structures which could bridge the electrodes, each with their own specific conductance value. The use of histograms with a Log10 scale for conductance proved useful for observing broad range features. vi Another factor which affects the conductance signal is the geometric alignment of the molecule (or the molecule-solvent structure) to the gold electrode, and the molecular alignment is explored in Chapters 3 for 1,10-phenanthroline (PHEN) and Chapter 4 for thiols. In Chapter 3 STM images, electrochemistry, and Density Functional Theory (DFT) are used to determine 1,10-phenanthroline (PHEN) structures on the Au(111) surface. It is established that PHEN binds in two modes, a physisorbed state and a chemisorbed state. The chemisorbed state is more stable and involves the extraction of gold from the bulk to form adatom-PHEN entities which are highly mobile on the gold surface. Surface pitting is viewed as evidential of the formation of the adatom-molecule entities. DFT calculations in this chapter were performed by Ante Bilic and Jeffery Reimers. The conclusions to Chapter 3 implicate the adatom as a binding mode of thiols to gold and this is explored in Chapter 4 by a timely review of nascent research in the field. The adatom motif is identified as the major binding structure for thiol terminated molecules to gold, using the explanation of surface pitting in Chapter 3 as major evidence and substantiated by emergent literature, both experimental and theoretical. Furthermore, the effect of this binding mode on conductance is explored and structures relevant to the break-junction experiment of Chapter 2 are identified and their conductance values compared. Finally, as a result of researching extensive reports of molecular conductance values, and having attempted the same, a simple method for predicting the conductance of single molecules is presented based upon the tunneling conductance formula.
7
Zbořilová, Hana. "Studium membránových vlastností liposomálních systémů pomocí fluorescenční spektroskopie." Master's thesis, Vysoké učení technické v Brně. Fakulta chemická, 2021. http://www.nusl.cz/ntk/nusl-449373.
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The presented diploma thesis is focused on the preparation, characterization and study of membrane properties of liposomal systems which were composed of the neutral phosphatidylcholine (DPPC), cholesterol, negatively charged phosphatidylglycerol (DPPG), polyethylenglycol bounded to phosphatidylethanolamine (PEG5000–PE) and polycation N,N,N-trimethylchitosan (TMC). The influence of individual components and their concentrations on the average particle size, zeta potential and changes in the outer and inner part of the bilayer was investigated. In this matter, methods of dynamic and electrophoretic light scattering and fluorescence spectroscopy with the application of laurdan and DPH probes were used. Based on the above-mentioned parameters, concentrations of components that most suitably influence properties of liposomes in terms of the intended application were selected for the definite complex. It was managed to prepare a liposomal complex stealth liposome–N,N,N-trimethylchitosan, which, due to the optimized composition, could have suitable attributes as a drug delivery system for inhalation administration of biologically active substances.
8
Chi, Danny T., and Nien-Lou Li. "DPPM Optical Communications and Reed-Solomon Codes." International Foundation for Telemetering, 1992. http://hdl.handle.net/10150/608918.
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International Telemetering Conference Proceedings / October 26-29, 1992 / Town and Country Hotel and Convention Center, San Diego, CaliforniaPulse position modulation (PPM) has many attractions for optical communication over deep space and for intersatellite communications. This paper describes a variate of PPM, known as differential pulse position modulation (DPPM) which can double the data throughput relative to PPM. We begin this paper with a survey of various laser sources and laser modulation techniques used in modem space optical communications. We then discuss the advantages of the combination of DPPM and Reed-Solomon (RS) codes.
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López-Amaya, Clara Inés. "Interaction of Candida rugosa lipase with DPPC liposomes." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp05/nq27441.pdf.
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Kell, Henny. "Wechselwirkung des Lipoheptapeptides Surfactin mit Lipiddoppelschichten aus DMPC und DPPC." [S.l.] : [s.n.], 2006. http://opus.kobv.de/tuberlin/volltexte/2007/1463.
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Cigánek, Martin. "Syntéza a studium nových derivátů diketopyrrolopyrrolů (DPPs) pro organickou elektroniku." Master's thesis, Vysoké učení technické v Brně. Fakulta chemická, 2017. http://www.nusl.cz/ntk/nusl-316170.
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This diploma thesis describes organic pigments of diketopyrrolopyrroles (DDPs) possessing properties applicable in attractive and perspective areas of organic electronics and photonics. The modification of the DPP skeleton was performed by nucleophilic substitution by various alkyl chains and 5 series of DPP derivatives were prepared. The regioselectivity of N-alkylation and also the photophysical properties of the prepared derivatives were studied. A key product of this work is the N,N'-ethyladamantyl derivative of DPP, which exhibited ambipolar characteristic with excellent electron mobility of 0.2 cm2 V–1 s–1. Further, the -conjugation of the above-mentioned DPP derivative was extended by 1 and 2 thiophene units at positions 3,6 and the effect of this modification on optical properties of the resulting derivatives was investigated. A new modified N,N'-unsubstituted DPP derivative was also prepared. The last point of this thesis was the study of the incorporation of formyl functional groups into the skeleton of key N,N'-ethyladamantyl DPP derivative.
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Silva, Mauro Marcos da. "Estudo da composição Química do óleo essencial de Lippia microphylla CHAM em três anos diferentes e atividade antioxidante." Universidade Federal de Roraima, 2014. http://www.bdtd.ufrr.br/tde_busca/arquivo.php?codArquivo=249.
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Coordenação de Aperfeiçoamento de Pessoal de Nível SuperiorO estado de Roraima é dividido em três grandes sistemas ecológicos: floresta, campinas-campinarana e savanas ou cerrados e está localizado no extremo norte da Amazônia brasileira. Apesar da grande variedade de plantas existem poucas informações sobre plantas aromáticas da região. Lippia microphylla Cham., pertence à família Verbenaceae e ao gênero Lippia, e conhecida popularmente em Roraima como salva do campo, sendo encontrada nos lavrados roraimenses. Esta planta pode ser encontrada com facilidade ao longo da BR 174 que liga Boa Vista a Santa Elena de Uairén, na Venezuela. O objetivo desse trabalho foi avaliar a constituição química do óleo essencial de Lippia microphylla Cham. em épocas e horários diferentes e analisar sua atividade antioxidante. As amostras foram coletadas no município de Boa Vista, Roraima, em três horários diferentes (8,12 e 18 horas) nos meses de maio 2009, 2010 e 2011. As folhas extraídas por hidrodestilação com auxílio de um aparelho de clevenger e os óleos foram analisados por cromatografia gasosa com auxílio da espectrometria de massas. Para determinação da atividade antioxidante do óleo essencial foi utilizado o método de capacidade sequestrante do radical livre DPPH. Os maiores rendimentos de óleos foram registrados em maio de 2011, mês que registrou maior precipitação, mas não choveu no dia da coleta. A análise da constituição do óleo revelou que o timol, carvacrol, E-cariofileno, nerolidol e o óxido de cariofileno foram os principais constituintes, sendo o carvacrol majoritário em quase todas as análises. O óleo de melhor capacidade antioxidante foi extraído do material coletado ao meio dia e contem maior concentração de timol (9,22%) e carvacrol (19,80%). Observamos que os óleos coletados nos diferentes anos apresentam diferenças significativas quanto a sua composição química e ao seu rendimento. A chuva do dia da coleta foi mais relevante do que o volume de precipitação no mês. A atividade antioxidante desses óleos pode ser atribuída principalmente à presença dos dois isômeros fenólicos.
The state of Roraima is divided into three major ecological systems: forests, meadow-campinarana and savannas, and are located in the extreme north of the Brazilian Amazon. Despite the wide variety of plants there is little information on herbs of the region. The Lippia microphylla Cham., belongs to the family Verbenaceae and the genus Lippia, popularly known as salva-do-campo being found in the Roraima savannas. This plant is easily found along the margins of the BR 174, the route Boa Vista, Brazil, to the Santa Elena de Uairén, Venezuela. The aim of this study was to evaluate the chemical composition of essential oil of Lippia microphylla Cham. Collected at different times and schedules and analyze their antioxidant activity. The samples were collected in Boa Vista, Roraima, at three different times ( 8, 12 and 18 hours ) in May 2009, 2010 and 2011, for realization of antioxidant activity the samples were collected in the month of March 2011. The leaves were extracted by hydrodistillation with the assistance of a Clevenger apparatus and the oils analyzed by Gas chromatography coupled with mass spectrometry, GC-MS. To determine the antioxidant activity of the essential oil the method of sequestering ability of the free radical DPPH was used. The highest yields of oils were recorded in May 2011, which recorded highest rainfall month, but it did not rain on the day of collection. The analysis of the constitution of the oils revealed that thymol, carvacrol, E-caryophyllene, nerolidol and caryophyllene oxide were the main constituents of which the majority carvacrol was in almost all analyzes. The best antioxidant capacity oil was extracted from material collected at noon containing higher concentration of thymol ( 9.22% ) and carvacrol ( 19.80% ). We observed that the oils collected in different years showed significant differences in their chemical composition and yield. The rain on the day of collection was more important than the volume of rainfall in the month. The antioxidant activity of these oils can be attributed mainly to the presence of two phenolic isomers.
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Morton, Colin J. H. "Novel derivatives of DPP and related heterocycles." Thesis, University of St Andrews, 1999. http://hdl.handle.net/10023/15291.
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This thesis discusses the synthesis of new organic, heterocyclic materials for potential application as pigments. Chapter 1 comprises an introduction to the field of pigment and dye chemistry, discussing the rudimentary elements of colour theory, before advancing to a review of the pertinent literature regarding high performance organic pigments. In particular, the development of 1,4-diketopyrrolo[3,4-c]pyrrole (DPP) pigments is described and the central objective of synthesising alkenyl-DPPs is outlined. Chapters 2 and 3 describe synthetic efforts towards alkenyl-DPPs, employing retro Diels-Alder methodology. The reactions involving the furan-acrylonitrile adduct as the nitrile component in the standard DPP synthesis led mainly to aromatisation of the bicyclic system and the cyclopentadiene-acrylonitrile adduct failed to react altogether. The explanation for this failure has been investigated. In the course of this these studies, several DPPs incorporating a secondary alkyl substituent were prepared, not least a novel cyclohexenyl-DPP. Chapter 4 describes the use of α β-unsaturated nitriles in the standard DPP synthesis. These behaved as Michael acceptors and in the case of cinnamonitriles led to a new family of coloured materials, namely substituted 4-hydroxy-2/7- cyclopenta[c]pyrrol-1-one-5-carbonitriles. Chapter 5 describes the corresponding reaction of cinnamate esters, but in these cases bicyclic systems were not formed. The reactions are analogous to Claisen acylations and the stereochemistry of the products varied according to the substituents. Chapter 6 contains the detailed experimental work for these investigations and concludes with a portfolio of X-ray structural data.
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Ponsot, Flavien. "Hybrides bactériochlorine-dicétopyrrolopyrrole (DPP) : Nouveaux fluorophores proche infrarouge pour des applications en biodétection/bioimagerie." Thesis, Bourgogne Franche-Comté, 2020. https://nuxeo.u-bourgogne.fr/nuxeo/site/esupversions/1fa27cab-663e-4192-be47-cd34a712a1cd.
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Les fluorophores organiques absorbant et émettant dans le proche infrarouge (700-900 nm, première fenêtre thérapeutique NIR-I) sont des outils de choix pour une application en bioimagerie. En effet, l'absorption, la diffusion et l'autofluorescence de constituants du milieu biologiques sont limitées dans cette région spectrale, rendant les tissus relativement transparents à ces longueurs d'onde. Les bactériochlorines sont des dérivés de porphyrines dont deux doubles liaisons sont réduites. Ces molécules présentent une forte absorption et une émission dans le NIR-I. Les DPP sont des fluorophores, structurellement plus simples, aux propriétés très intéressantes. Ils présentent un rendement quantique de fluorescence élevé, un grande photostabilité et sont également très stable chimiquement et thermiquement. L'objectif de cette thèse est d'associer ces deux fluorophores et d'accéder à de nouvelles architectures multi-chromophoriques d'intérêt et combinant leurs propriétés complémentaires. Les DPP utilisés dans la construction de ces structures hybrides, très modulables pourront être adaptés à la détection d'activités enzymatiques d'intérêt en milieu biologique, par introduction d'un motif de reconnaissance spécifique de l'analyte et de groupements hydrosolubilisantsNear-infrared (700-900 nm) absorbing and emitting organic-based fluorophores are valuable tools for bioimaging applications. Indeed, biological component absorption, diffusion and autofluorescence are quite low in this region (known as the first therapeutic window NIR-I), making tissues relatively transparent to these long wavelengths. Bacteriochlorins are porphyrins derivatives in which two double bonds are reduced. These molecules display a strong absorption and emission within NIR-I spectral range. DPPs are structurally simpler fluorophores displaying very interesting properties. They have high fluorescence quantum yields, are highly (photo)chemically and thermally stable. The aim of this thesis is to associate these two fluorophore units in order to yield novel multi-chromophoric molecular architectures that combine their complementary properties. DPP dyes used in the design of the hybrids are highly versatile. They can be used as fluorogenic reporters for the detection of relevant enzymatic activities in the biological media by introducing a specific triggering unit of the targeted analyte and water-solubilizing moieties
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Coat, Françoise. "Elaboration et proprietes de chaines de carbone inorganique stabilisees par les groupements terminaux (c#5me#5)(dppe)fe(ii) et (c#5me#5)(dppe)fe(iii)." Rennes 1, 1995. http://www.theses.fr/1995REN10141.
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Ce memoire de these presente la synthese et la caracterisation de nouveaux complexes homobinucleaires du fer de type donneur-accepteur en serie fe(c5me5)(dppe) et fe(c5me5)(co)2 a chaine -butadiynediyle fe(c5me5)(dppe)-( -cc cc)-fe(c5me5)(co)2n+ (n = 0, 1) ainsi que celles de complexes bimetalliques symetriques du fer en serie fe(c5me5)(dppe) a ligand pontant -octatetraynediyle fe(c5me5)(dppe)2-(-cccccccc)n+ (n = 0, 1, 2). Deux nouveaux complexes cumuleniques mono- et binucleaires fe(c5me5)(dppe)(=c=c=c(ome)me)bph4 et fe(c5me5)(dppe)-(=c=c=c=ch)-fe(c5me5)(co)2bf4 ont ete prepares avec de bons rendements par activation de derives de butadiyne par un organofer. Le complexe fe(c5me5)(co)2(ccccmts), prepare a partir du complexe fe(c5me5)(co)2l, a permis d'acceder a son analogue a ligand 1,3-butadiynyle par clivage de la liaison carbone-silicium. Ce dernier reagit avec le fe(c5me5)(dppe)cl pour donner le complexe de type donneur-accepteur fe(c5me5)(dppe)-(-cccc)-fe(c5me5)(co)2 presentant une interaction metal-metal. L'oxydation chimique monoelectronique du derive bis-feii a permis d'obtenir le complexe a valence mixte feii-feiii stable, presentant un couplage electronique notable (vab = 0,11 ev). Le complexe fe(c5me5)(dppe)(cccctms), obtenu par photochimie, conduit, par desilylation, au fe(c5me5)(dppe)(cccch) avec un bon rendement. Le complexe fe(c5me5)(dppe)2-(-cccccccc), a ete synthetise par couplage oxydant et caracterise. Une forte interaction entre les centres metalliques distants de 12,6 a a ete demontree. Le complexe bis-feii est facilement oxyde par un ou deux equivalents de sel de ferricinium et les especes stables feii-feiii et feiii-feiii resultantes ont ete isolees. Les spectroscopies mossbauer, ir et electronique ont permis de mettre en evidence, dans le complexe a valence mixte fe(c5me5)(dppe)2-(-cccccccc)pf6, le transfert d'electron intramoleculaire. Le ligand pontant carbone favorise efficacement le couplage electronique, lequel, presente la plus forte valeur (vab = 0,32 ev) jamais observee entre deux metaux a travers neuf liaisons. Ce complexe constitue donc, en ce sens, un fil moleculaire. Les complexes bis-feii, bis-feiii et feii-feiii ont revele des proprietes en optique non lineaire et les valeurs de sont parmi les plus elevees.
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LE, STANG SYLVIE. "Nouveaux composes modeles pour l'electronique moleculaire en serie cp*fe(dppe)-c 2-x-c 2-fe(dppe)cp* n + (n = 0 2, x = heterocycles aromatiques)." Rennes 1, 2000. http://www.theses.fr/2000REN10038.
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Ce manuscrit decrit la synthese et l'etude de nouveaux complexes mono- et bi-nucleaires en serie cp*fe(dppe). Les sites metalliques electroactifs portent des ligands mono- et bis-ethynylheteroaromatiques a travers lesquels peut s'etablir une communication electronique et/ou magnetique. Ces nouvelles molecules de dimension nanoscopique constituent des composes modeles pour l'electronique moleculaire. La reaction de sonogashira a permis d'acceder aux trois complexes cp*fe(dppe)-cc-c 5h 4n 4 a partir du compose cp*fe(dppe)-cc-h et des trois bromopyridines correspondantes. La complexation de ces molecules avec des complexes du palladium et du platine a permis de valider le concept de fils moleculaires auto-assembles. La synthese des complexes bimetalliques cp*fe(dppe)(cc-) 2c 5h 3n (6a:2,6-c 5h 3n ; 6b:3,5-c 5h 3n) et cp*fe(dppe)(cc-) 22,5-c 4h 2s 9 est realisee en une etape a partir du compose cp*fe(dppe)cl 1 et des bis-acetylures heteroaromatiques proteges. L'etude par voltametrie cyclique de ces derives a permis de determiner la stabilite en solution des especes a valence mixte. L'oxydation a deux electrons des complexes 6 conduit aux composes biradicalaires 6 + +. L'existence d'un couplage magnetique a ete mis en evidence par l'observation de l'etat triplet en rpe. Dans le compose a valence mixte 6a +, l'azote favorise le couplage electronique alors que dans le derive 6b +, il apparait comme un isolant dans la chaine carbonee. L'oxydation en cascade du complexe 9 conduit aux composes mono- et di-oxydes. Le complexe 9 + + existe sous deux formes en equilibre : une forme bis-radicalaire fer(iii) et une forme cumulenique fer(ii). Dans le complexe 9 +, l'electron celibataire est delocalise aux echelles de temps des spectroscopies mossbauer et rpe. Le couplage electronique est fort pour un transfert electronique mettant en jeu neuf liaisons (v a b = 2515 cm - 1) et comparable a celui determine pour le complexe cp*fe(dppe) 2cc-cc-cc-ccpf 6 (v a b = 2520 cm - 1).
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da, Cunha Amaral Lima Danielle. "Estudo comparativo da atividade antioxidante de plantas medicinais da caatinga utilizadas como antiinflamatórias." Universidade Federal de Pernambuco, 2011. https://repositorio.ufpe.br/handle/123456789/3324.
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Previous issue date: 2011Plantas com atividade antioxidante podem estar envolvidas no tratamento e/ou prevenção de diversas enfermidades, em especial as que envolvem processos inflamatórios. Foram selecionadas vinte espécies de plantas utilizadas para tratar inflamação pela comunidade de Carão, localizada em Altinho-PE, e dezenove espécies de forma aleatória. A coleta foi realizada na referida região no mês de setembro de 2009, de no mínimo 3 indivíduos de cada espécies, submetidas a extração por maceração com metanol 80% durante 6 dias e evaporado o solvente sob pressão reduzida. Buscando avaliar a correlação entre métodos utilizados para determinar a atividade antioxidante foram aplicados três: atividade sequestrante de radical livre DPPH (DPPH), ensaio da atividade quelante do íon ferroso (FIC) e poder antioxidante redutor férrico (FRAP). Avaliou-se também o poder antioxidante de espécies utilizadas para tratamento de inflamações comparadas às espécies selecionadas de forma aleatória. Observou-se que não houve correlação entre os métodos FIC e DPPH (rs = -0,3008 e p = 0,1975) e entre FIC e FRAP (rs = 0,3042 e p = 0,1921). Entretanto, foi possível observar correlação significativa entre FRAP e DPPH (rs = -0,9563 e p = < 0,0001). Através da análise de variância de Kruskal-Wallis os dois grupos de espécies estudadas foram estatisticamente iguais através dos métodos DPPH e FRAP e que as espécies aleatórias foram estatisticamente mais efetivas quando avaliado o poder quelante do íon ferroso. Contudo, quando utilizada a classificação de Melo et al (2010), observa-se que 45% das espécies antiinflamatórias apresentaram boa atividade seqüestradora de radicais livres comparadas às 36,84% das aleatórias. Conclui-se que os métodos utilizados avaliam a atividade antioxidante por meio de mecanismos distintos, não sendo recomendável o emprego de um único método para determinação da atividade antioxidante. Sendo o método DPPH mais indicado para avaliar a atividade antioxidante de espécies utilizadas para tratar inflamação. Dados sugerem que as espécies anttinflamatórias não agem quelando o íon ferroso, não sendo este método mais indicado para avaliação da atividade antioxidante de espécies antiinflamatórias, visto a quelação de metais de transição tem um papel secundário no mecanismo de inibição dos radicais livres
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Tran, Tinh Vi. "The hydrolysis rate of fluorescent dipeptides by dipeptidyl peptidase I (DPPI)." Thesis, Georgia Institute of Technology, 1999. http://hdl.handle.net/1853/10132.
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Zander, Thomas [Verfasser], and Andreas [Akademischer Betreuer] Schreyer. "The interaction of DPPC and hyaluronan / Thomas Zander ; Betreuer: Andreas Schreyer." Hamburg : Staats- und Universitätsbibliothek Hamburg, 2016. http://d-nb.info/1116604590/34.
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Zander, Thomas Verfasser], and Andreas [Akademischer Betreuer] [Schreyer. "The interaction of DPPC and hyaluronan / Thomas Zander ; Betreuer: Andreas Schreyer." Hamburg : Staats- und Universitätsbibliothek Hamburg, 2016. http://nbn-resolving.de/urn:nbn:de:gbv:18-80661.
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Pantazis, Periklis. "Role of endocytic trafficking during Dpp gradient formation." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2004. http://nbn-resolving.de/urn:nbn:de:swb:14-1106665288062-25959.
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Morphogens are secreted signalling molecules that are expressed in restricted groups of cells within the developing tissue. From there, they are secreted and travel throughout the target field and form concentration gradients. These concentration profiles endow receiving cells with positional information. A number of experiments in Drosophila demonstrated that the morphogen Decapentaplegic (Dpp) forms activity gradients by inducing the expression of several target genes above distinct concentration thresholds at different distances from the source. This way, Dpp contributes to developmental fates in the target field such as the Drosophila wing disc. Although the tissue distribution as well as the actual shape and size of the Dpp morphogen concentration gradient has been visualized, the cell biological mechanisms through which the morphogen forms and maintains a gradient are still a subject of debate. Two hypotheses as to the dominant mechanism of movement have been proposed that can account for Dpp spreading throughout the Drosophila wing imaginal target tissue: extracellular diffusion and planar transcytosis, i. e. endocytosis and resecretion of the ligand that is thereby transported through the cells. Here, I present data indicating that implications of a theoreticalanalysis of Dpp spreading, where Dpp transport through the target tissue is solely based on extracellular diffusion taking into account receptor binding and subsequent internalization, are inconsistent with experimental results. By performing Fluorescence Recovery After Photobleaching (FRAP) experiments, I demonstrate a key role of Dynamin-mediated endocytosis for Dpp gradient formation. In addition, I show that most of GFP-Dpp traffics through endocytic compartments at the receiving epithelial cells, probably recycled through apical recycling endosomes (ARE). Finally, a Dpp recycling assay based on subcellular photouncage of ligand is presented to address specifically the Dpp recycling event at the receiving cells.
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Mamza, Jil Billy. "Comparative effectiveness and safety of DPP-4 inhibitors." Thesis, University of Nottingham, 2016. http://eprints.nottingham.ac.uk/33202/.
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Approximately 3 million people throughout the UK suffer with Type 2 diabetes mellitus (T2DM), and are 32% more likely to die early. There remains a lack of evidence for the long-term effectiveness and safety of anti-diabetic drugs in preventing diabetes-related complications, making it unclear how to optimally manage diabetes. Work to date includes observational studies subject to bias, and randomised controlled trials (RCTs), which may not reflect the ‘real world’ situation. The aim of this thesis is to combine such findings via systematic reviews, meta-analyses and retrospective cohort studies to provide more water-tight evidence of the effectiveness and safety of glucose-lowering therapies (GLT) in the long term. Firstly, a systematic review of observational studies was performed, identifying and providing a simple description of the types of biases and control measures employed in retrospective cohort studies on treatment outcomes of GLTs. Secondly, retrospective cohort studies were conducted to strengthen the evidence of the clinical effectiveness of DPP-4 inhibitors, compare their durability when combined with other anti-diabetic drugs and assess their cardiovascular safety when used in patients with T2DM, using data from The Health Improvement Network (THIN) database. Linear and logistic regression, Cox proportional hazard regression models and propensity score techniques were used to analyse routine clinical data. Thirdly, a meta-analysis was conducted on RCTs investigating the risk of bone fracture following the administration of DPP-4 inhibitor, based on data from an extensive literature search. Conducting this research has led to a better understanding of how biases may have influenced retrospective cohort studies on oral anti-diabetic drugs. An algorithm was developed to illustrate strategies for addressing biases. Potential clinical factors associated with ‘response’ to DPP-4 inhibitor treatment were found to include the addition of DPP-4 inhibitor to ongoing metformin (MET), or MET plus sulphonylurea (SU) therapy. High HbA1c at the time of treatment intensification and longer duration of diabetes were associated with the lack of HbA1c target attainment. In terms of the durability of second-line glucose-lowering agents, the co-administration of thiazolidinedione with MET was associated with the most durable glycaemic response, followed by a SU and then a DPP-4 inhibitor. Compared with a SU, adding a DPP-4 inhibitor to MET was associated with an increased need for earlier treatment intensification with a third agent. The use of statins, being a female, a smoker, having longer duration of diabetes and higher HbA1c at baseline were identified to be associated with earlier dual therapy failure. In terms of cardiovascular safety, routine clinical data showed patients who intensified MET + SU dual therapy with a DPP-4 inhibitor were associated with a decreased risk of a composite of non-fatal cardiovascular outcomes and all-cause mortality compared to those who added insulin. Furthermore, the results from meta-analysis showed DPP-4 inhibitors are not associated with increased bone fracture risks in patients with T2DM. This research is valuable in informing the choices of healthcare professionals in prescribing treatments for T2DM. For the users of this treatment, it is good news that DPP-4 inhibitors are not generally associated with fracture incidence, and that findings support the use of DPP-4 inhibitors as a second line therapeutic option, especially among non-obese patients whose glucose control remains suboptimal following MET treatment. It is recommended that treatment should be characterised on an individual basis. There remains a need for robust RCTs to investigate the influence of obesity and longer treatment durations on the efficacy of co-administering DPP-4 inhibitors to patients who are unresponsive to other oral GLTs.
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Pantazis, Periklis. "Role of endocytic trafficking during Dpp gradient formation." [S.l. : s.n.], 2005. http://www.bsz-bw.de/cgi-bin/xvms.cgi?SWB11611845.
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Sandrino, Bianca. "Estudo do complexo mer-[RuCl3(dppb)(VPy)]: síntese, caracterização e potenciais aplicações." UNIVERSIDADE ESTADUAL DE PONTA GROSSA, 2010. http://tede2.uepg.br/jspui/handle/prefix/2086.
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Previous issue date: 2010-03-05Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
The synthesis of biphosphine complex, specifically containing the unit “[RuCln(dppb)]” (dppb = 1,4-bis(diphenylphosphino) butane), has attracted considerable interest due to applications in catalysis for hydrogenation of organic compounds and more recently in biological activities and modified electrodes due to its stability and promising redox property. Within this perspective, in this work the complex mer-[RuCl3(dppb)(VPy)] (VPy = 4-vinylpyridine), RuVPy was synthesized from the replacement of the aqua ligand of the complex mer-[RuCl3(dppb)H2O] by ligand 4-vinylpyridine in the ratio 1:1.1 (complex / ligand). Spectroscopic results indicated that the incorporation of the ligands dppb and VPy yielded bands at 435, 516, 1002, 1087, 1433 and 1484 cm-1, 262, 390, 450, 530 nm coincident with spectra of the serie complex mer-[RuCl3(dppb)(L)] (N-heterocyclic). Values of g tensor (g1 = 2.40, g2 = 2.00 and g3 = 1.69) confirmed the meridional arrangement of chloride ligands around the octahedral complex geometry. An interesting voltammetric profile was observed for RuVPy solution due to the presence of three peaks with oxidation potential values of 0.07, 0.42 and 0.54 V (vs. Ag/AgCl) that emerged after the reduction of core metallic -0.07 V, attributed to redox processes of complexes [Ru2Cl5(dppb)2], [RuCl2(dppb)(4-VPy)2] and [Ru2Cl4(dppb)2(4-VPy)] formed in solution. Immobilization the RuVPy on different surfaces (LB films, casted film, dip-coated film and carbon paste) revealed only one electrochemical process around 0.55 V (vs. Ag/AgCl) assigned to the redox couple RuII/RuIII. Also, was found that the nature of the nanostructured LB films of RuVpy compared to thick films without structural organization due to the higher peak current compared to the films casted films, dip-coated electrode and carbon paste. The versatility of the RuVpy complex was demonstrated by the conversion of 82.5% of cyclohexene in cyclohexane in the hydrogenation catalysis and the conversion of 91% of cyclooctene in epoxide in the oxidation catalysis. Finally, preliminary catalytic tests showed a lower conversion (67%) in the oxidation of cyclooctene when RuVPy is immobilized on silica.
A síntese de complexos bifosfínicos metálicos, mais especificamente contendo a unidade “[RuCln(dppb)]” (dppb= 1,4-bis(difenilfosfina)butano), tem atraído considerável interesse devido às aplicações em catálise de hidrogenação de compostos orgânicos e mais recentemente em atividades biológicas e eletrodos modificados devido a sua estabilidade e promissora propriedade redox. Dentro desta perspectiva neste trabalho sintetizou-se o complexo mer-[RuCl3(dppb)(VPy)] (VPy= 4-vinilpiridina), RuVPy, a partir da substituição do ligante aqua do complexo mer-[RuCl3(dppb)H2O] pelo ligante 4-vinilpiridina na proporção 1:1,1 (complexo/ligante). Resultados espectroscópicos indicaram que houve a incorporação dos ligantes Vpy e dppb, a partir das bandas em 435, 516, 1002, 1087, 1433 e 1484 cm-1, e 262, 390, 450, 530 nm coincidentes com espectros da série de complexos mer-[RuCl3(dppb)L] (N-heterocíclico). Valores de tensor g (g1= 2,40, g2= 2,00 e g3= 1,69) confirmaram a disposição meridional dos ligantes cloretos ao redor da geometria octaédrica do complexo. Um interessante perfil voltamétrico foi observado para o RuVPy em solução, devido à presença de três picos de oxidação com valores de potenciais em 0,07, 0,42 e 0,54 V (vs Ag/AgCl) que surgiram após a redução do centro metálico em -0,07 V, atribuídos aos processos redox dos complexos [Ru2Cl5(dppb)2], [RuCl2(dppb)(4-VPy)2] e [Ru2Cl4(dppb)2(4-VPy)] formados em solução. Ao imobilizar o RuVPy em diferentes superfícies eletródicas (filmes LB, casted, dip-coated e pasta de carbono) observou-se somente um processo em torno de 0,55 V (vs Ag/AgCl) atribuído ao par redox RuII/RuIII. Além disto, constatou-se a natureza nanoestruturada dos filmes LB do RuVpy em função da maior corrente de pico em relação aos filmes casted, dip-coated e do eletrodo de pasta de carbono. A versatilidade do complexo RuVpy foi demonstrada pela conversão de 82,5% de cicloexeno em cicloexano em catálise de hidrogenação, bem como pela conversão de 91% do cicloocteno em epóxido na catálise de oxidação. Por fim, em testes catalíticos preliminares constatou-se menor conversão (67%) na oxidação do cicloocteno quando o RuVPy é imobilizado em sílica.
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Gangadharan, Komala Muralikrishna. "The Role of SGLT2 Inhibitors and DPP4 Inhibitors in Preventing Diabetic Nephropathy." Thesis, The University of Sydney, 2016. http://hdl.handle.net/2123/15925.
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Diabetic nephropathy is the most common cause of end stage kidney disease in the world. Newer diabetic medications have arrived over the last few years. However there is lack of experimental and clinical evidence in favour of better outcomes. The two most important drug categories that have emerged in this century are the dipeptidyl peptidase-4 inhibitors DPP4 inhibitors (DPP4i) and sodium glucose cotransporter inhibitors (SGLT2i). Their role in preventing diabetic nephropathy irrespective of their glycaemic benefits is unknown. The aim of our project was to demonstrate the renoprotective benefits of these medications. In this thesis we used endothelial nitric oxide synthase knock out (eNOS -/-) mice and induced type 1 diabetes using streptozotocin (STZ) injection. We studied the changes of diabetic nephropathy in these mice including clinical outcomes, biochemical changes, inflammatory and fibrotic pathways. Our study with empagliflozin showed that SGLT2 inhibitors might not have a beneficial role in preventing diabetic nephropathy when blood glucose levels were high. We studied the role of linagliptin, a DPP4i, in preventing the interaction between DPP4 and cation independent mannose-6-phosphate receptor (CIM6PR) in the setting of high glucose in an in vitro model using kidney proximal tubular cells. Our results showed that linagliptin reduced the interaction between DPP4 and CIM6PR possibly resulting in the prevention of activation of latent TGFß. We proved this subsequently in an in vivo model of STZ induced type 1diabetes in eNOS -/- mice using linagliptin and another DPP4i, saxagliptin. We demonstrated that these DPP4i were able to reduce tubulointerstitial fibronectin deposition and demonstrated reduced expression of pSmad2/3, a downstream marker of TGFß activation. Hence our studies have helped in partly identifying the puzzle of diabetic nephropathy and provide some answers on the role of newer anti diabetic agents in preventing it.
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Monteiro, Vania Claudia Barros. "Avaliação do estresse oxidativo em humanos e em animais suplementados com ácidos graxos polinsaturados omega-3." Universidade de São Paulo, 2007. http://www.teses.usp.br/teses/disponiveis/9/9131/tde-29052007-092628/.
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Ácidos graxos polinsaturados Omega-3 (n-3 PUFA) tais como o ácido eicosapentaenóico (C20:5 n-3, EPA) e docosahexaenóico (C22:6 n-3, DHA) reduzem a concentração plasmática de triacilgliceróis em humanos. Entretanto, uma alta proporção desses ácidos graxos na dieta poderia favorecer a susceptibilidade das células à peroxidação, aumentando o risco de desenvolvimento de doenças cardiovasculares. Embora modelos animais não sejam recomendados para avaliar o efeito de n-3 PUFA nas lipoproteínas plasmáticas, estes têm sido amplamente utilizados como modelo para avaliação de dano oxidativo. Diferenças nos procedimentos metodológicos também têm gerado dificuldade na comparação de resultados. Desta forma, o objetivo deste estudo foi aplicar os mesmos procedimentos metodológicos para comparar o efeito da suplementação de n-3 PUFA nos biomarcadores plasmáticos de estresse oxidativo utilizando um modelo humano e um modelo animal. Indivíduos foram aleatoriamente distribuídos em dois grupos num delineamento paralelo duplo cego e receberam uma suplementação de 460,0 mg/dia de n-3 PUFA (OMEGA) contendo 240,0 mg de EPA + 160,0 mg de DHA + 60,0 mg de outros n-3 PUFAs, ou óleo de soja (PLACEBO) durante 6 semanas. Ratos Wistar também foram distribuídos em dois grupos e receberam uma dieta contendo 192,5 mg/dia de n-3 PUFA (FO) sendo 116,3 mg de EPA + 61,5 mg de DHA + 14,7 mg de outros n-3 PUFAs ou óleo de soja (SO) durante 3 semanas. Indivíduos do grupo OMEGA apresentaram maior concentração de malondialdeído (MDA) no plasma medido por TBARS quando comparado aos respectivos valores no baseline. A suplementação com n-3 PUFA não alterou a concentração plasmática de α-tocoferol e a atividade antioxidante determinada pelo método DPPH. Apesar dos animais terem recebido doses 10 vezes maiores de n-3 PUFA (2,9 mg/kcal) quando comparadas aos humanos (0,3 mg/kcal) não foram observadas alterações entre os grupos FO e SO para as concentrações de MDA no plasma e no homogenato de cérebro. Em resumo, pode-se sugerir que o modelo animal usado neste estudo parece não ser o mais adequado para avaliar o estresse oxidativo após intervenções dietéticas com n-3 PUFAs em função de diferenças no metabolismo e nos mecanismos de proteção antioxidante observados entre os dois modelos.Omega-3 polyunsaturated fatty acids (n-3 PUFA) such as eicosapentaenoic (C20:5 n-3, EPA) and docosahexaenoic (C22:6 n-3, DHA) reduce plasma triacylglycerol concentration in humans. However, higher proportion of these fatty acids in the diet could raise cells lipoperoxidation susceptibility, increasing the cardiovascular disease risk. Although animal models are not recommended to evaluate the effect of n-3 PUFA in plasma lipoproteins, they have been widely used as model for oxidative damage. Difference in methodological proceedings has also caused difficulties to compare data among assays. Thus, the objective of this study was to apply the same methodology to investigate the effect of n-3 PUFA supplementation on oxidative biomarkers in animal and human model. Individuals were randomly assigned in two groups in a parallel double blind design and received a supplement of 460.0 mg/day n-3 PUFA (OMEGA) containing 240.0 mg EPA + 160.0 mg DHA + 60.0 mg other n-3 PUFAs, or soybean oil (PLACEBO) during 6 weeks. Wistar rats were also assigned in two groups and received a diet containing 192.5 mg/day n-3 PUFA (FO) containing 116.3 mg EPA + 61.5 mg DHA + 14.7 mg other n-3 PUFAs or soybean oil (SO) for 3 weeks. Individuals in OMEGA group showed higher malondialdehyde (MDA) concentration in plasma measured by TBARS when compared to their baseline values. N-3 PUFA supplementation did not change plasma α-tocopherol concentration and antioxidant activity determined by DPPH method. Although animals have received a 10-fold higher dose of n-3 PUFA (2.9 mg/ kcal) than humans (0.3 mg/kcal), no alteration was observed between FO and SO groups for plasma and brain homogenate MDA concentration. In summary, it can be suggested that the model used in this study doesn\'t seem appropriate to evaluate oxidative stress after dietetic interventions with n-3 PUFA due to physiological differences involved in lipid metabolism and antioxidant protection observed between both models.
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Calomeni, Andressa do Valle. "Utilização de película de amendoim para produção de pigmento natural em pó: estudo do efeito do processo de atomização na estabilidade, propriedades antioxidante e antimicrobiana do material." Universidade de São Paulo, 2015. http://www.teses.usp.br/teses/disponiveis/74/74132/tde-03022016-162446/.
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A película do amendoim apresenta coloração vermelha intensa e é rica em compostos fenólicos, todavia o extrato líquido é instável e de difícil comercialização. Os objetivos deste trabalho foram extrair os pigmentos da película do amendoim, estudar o processo de secagem por atomização deste extrato, caracterizar os pós obtidos, bem como sua propriedade antioxidante, antimicrobiana e estabilidade durante o armazenamento, sempre comparando com o controle. Quanto a caracterização do extrato líquido foi analisado fenólicos totais, pH, umidade, cinzas, proteínas, lipídeos, açúcares, aflatoxina e acidez. Os extratos foram então misturados com agente carreador nas concentrações de 10, 20 e 30%, estes foram atomizados em spray dryer com temperaturas do ar de entrada de 130, 150 e 170ºC. Para obtenção da amostra controle, parte do extrato foi liofilizado sem a presença de agente carreador. Os pós obtidos foram caracterizados quanto à umidade, atividade de água, higroscopicidade, morfologia, tamanho das partículas, cor, teor de fenólicos totais, solubilidade, estabilidade, propriedade antimicrobiana e antioxidante pelos métodos: ORAC, DPPH e HPLC-ABTS on line. Na caracterização do extrato líquido foram obtidos os seguintes resultados: 0,24% de proteína, 2,31% de açúcares, 0,09% de cinzas, 1,41% de lipídeos, 0,91% de acidez titulável, 42,88 mg de ác. gálico eq./g de extrato (fenólicos totais), pH de 5,30, 90,93% de umidade e 1,81 ng aflatoxina/mL extrato (aflatoxina). Na caracterização dos pós, a umidade foi menor para pós secos a 170ºC e para concentração de 10% de maltodextrina e foi sempre menor que o controle. A higroscopicidade foi menor quanto maior a concentração de maltodextrina, pois esta tem baixa higroscopicidade. Temperaturas mais altas geraram pós mais higroscópicos, pois esses tinham menor umidade. Com relação à solubilidade, os valores variaram de 85,60 a 91,91%, obtendo-se maiores valores para pós com maiores concentrações de maltodextrina, pois esta apresenta elevados valores de solubilidade. O controle apresentou solubilidade mais baixa de 77,62%. Já os parâmetros de cor tiveram influência apenas da concentração de maltodextrina, sendo que as amostras com menor concentração apresentaram cor mais acentuada, o que era de se esperar visto que a maltodextrina apresenta coloração branca. Portanto, o controle sempre apresentou a coloração mais intensa frente aos pós atomizados. A temperatura de 170ºC originou pós de superfícies mais lisas, apresentando assim melhor escoamento. Com o estudo de estabilidade, verificou-se que as amostras atomizadas tiveram menor perda de cor em relação à liofilizada, e as amostras com maior concentração de maltodextrina (30%) preservaram melhor os fenólicos totais, destacando-se a temperatura de 150 ºC. Em relação à atividade antioxidante, o tratamento T5 se destacou frente aos outros, apresentando o melhor valor de atividade antioxidante por todos os métodos estudados. O extrato da película de amendoim em pó também apresentou atividade antimicrobiana contra as bactérias Gram-positivas Staphylococcus aureus e Listeria monocytogenes, apresentando ainda capacidade bactericida para Staphylococcus aureus. Frente a esse estudo, tem-se na película de amendoim um potencial aditivo natural, podendo ser utilizado como pigmento em pó que apresenta excelente estabilidade, baixa higroscopicidade e alta solubilidade; além de apresentar atividades biológicas como capacidade antioxidante e antimicrobiana.The peanut skin presents intense red color and is rich in phenolic compounds, however the liquid extract is unstable and difficult to commercialize. The aim of this project was to extract the pigments of peanut skin, study the process of spray drying this extract, characterize the powders as well as its antioxidant properties, antimicrobial properties and storage stability, when compared to the control. The extract was characterized measuring the phenolic compounds, pH, moisture, ash, protein, lipids, sugars, aflatoxin and acidity. The extracts were then mixed with the carrier agent at concentrations of 10, 20 and 30%, these were atomized in a spray dryer at inlet air temperatures of 130, 150 and 170 º C. To obtain a control sample, part of the extract was freeze-dried without the presence of maltodextrin. The powders were characterized for moisture, water activity, hygroscopicity, morphology, particle size, color, total phenolic content, solubility, stability, antimicrobial and antioxidant properties by the methods: ORAC, DPPH and ABTS HPLC-online. In the analysis of the liquid extract, the following results were obtained: 0.24% protein, 2.31% sugar, 0.09% ash, 1.41% lipid, 0.91% titratable acidity, 42.88 mg of Galic acid eq. / g extract (phenolic), pH of 5.30, 90.93% moisture and 1.81 ng aflatoxin / mL extract (aflatoxin). In the analysis of the powders, moisture was lower for powders dried at 170ºC and with 10% maltodextrin concentration and was always lower than the control. The hygroscopicity is lower as higher the concentration of maltodextrin, since the last has low hygroscopicity. Higher temperatures generated more hygroscopic powders, because they reduced moisture. In concern to solubility, the values ranged from 85.60 to 91.91%; higher values were obtained for powders with higher concentrations of maltodextrin, since it has high solubility values. The control showed lower solubility of 77.62%. The color parameters were influenced only by the concentration of maltodextrin; the samples with lower concentrations showed more pronounced color, what was to be expected since maltodextrin is white. Therefore, controls have always presented with more intense color than the atomized powders. The temperature of 170 ºC originated powders with smoother surfaces, thus resulting in better flow. In the evaluation of stability, it was found that the atomized sample suffered lower color loss compared to the freeze dried sample, and samples with higher concentrations of maltodextrin (30%) had better preservation of total phenolics, especially at a temperature of 150ºC. In concern to antioxidant activity, the T5 treatment stood out compared to the others, showing the best values of antioxidant activity in all methods studied. The extract of peanut skin in powder also showed antimicrobial activity against Gram-positive bacteria Staphylococcus aureus and Listeria monocytogenes, with bactericidal properties against Staphylococcus aureus. This study clearly showed that peanut skin is a potential natural additive product and may be used as a powdered pigment which has excellent stability, low hygroscopicity and high solubility, besides having biological activities, such as antioxidant and antimicrobial capabilities.
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Souza, João Francisco Ventrici de. "Efeito de materiais particulados em sistemas modelos de biomembranas." Universidade de São Paulo, 2012. http://www.teses.usp.br/teses/disponiveis/59/59138/tde-13042012-144908/.
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Neste trabalho foram estudadas algumas propriedades de sistemas miméticos de tensoativos pulmonares (TP) constituídos de dipalmitoilfosfatidilcolina (DPPC) e DPPC/colesterol e suas interações com o material particulado (MP) proveniente da queima da palha da cana-de-açúcar, reconhecido por meio de estudos clínicos como agente agravador de diversas patologias respiratórias. O MP utilizado neste trabalho foi analisado por meio de uma série de técnicas: espalhamento dinâmico de luz (DLS), microscopia eletrônica de varredura acrescida do uso de análise de energia dispersiva de raios X (MEV e MEV-EDX) e espectroscopia de absorção na região do infravermelho. Os valores médios de tamanho e potencial zeta das partículas foram 250 nm e -27 mV, respectivamente. Isotermas de pressão superficial versus área por molécula de DPPC e DPPC/colesterol foram estudadas na ausência e presença de partículas e trouxeram informações a respeito da inserção das partículas nas monocamadas. O sistema DPPC/colesterol apresentou variações menores de área mínima por molécula com o aumento da concentração de MP, indicando que o colesterol atua como agente organizador da monocamada. Reologia superficial dilatacional dinâmica foi estudada pelo método de oscilação harmônica da gota pendente. Concentrações pequenas de MP aumentam a fluidez das monocamadas, enquanto concentrações mais elevadas aumentam a rigidez das mesmas. A presença de colesterol potencializa o efeito provocado pelo MP. Os dados de módulo de compressibilidade obtidos das isotermas se mostraram próximos daqueles obtidos nos estudos reológicos em frequências elevadas. As monocamadas foram transferidas para substratos sólidos por meio da técnica de Langmuir-Blodgett (LB). Os filmes LB resultantes foram analisados por meio de microscopia de força atômica (AFM) e microscopia do tempo de vida de fluorescência (FLIM). Ambas as técnicas mostraram que as partículas se depositam juntamente com o filme e que o sistema DPPC/colesterol dispõe de um arranjo mais homogêneo para as partículas. Imagens de FLIM mostraram que provavelmente esse arranjo se dá devido à preferência do colesterol em se alocar em regiões periféricas às partículas, conferindo estabilidade às mesmas na interface. O trabalho permitiu concluir que o MP proveniente da cana-de-açúcar possui efeito sobre algumas propriedades superficiais estudadas nos sistemas modelos de TP e que essas propriedades devem ter o potencial de interferir no perfeito funcionamento desses sistemas nos meios biológicos.This work presents some of the properties of mimetic systems of pulmonary surfactants (PS) composed of dipalmitoylphosphatidylcholine (DPPC) and DPPC/cholesterol and their interactions with particulate material (PM) originated from the burning of sugar cane leaves which is known by clinical studies as an injurious agent of the respiratory airways. The PM described in the present work was analyzed by different techniques: Dynamic Light Scattering (DLS), Scanning Electron Microscopy (SEM) with EDS (Energy Dispersive Spectrometry) and Fourier Transformed Infrared Spectroscopy (FTIR). The average values of size and zeta potential were 250 nm and -27 mV, respectively. DPPC and DPPC/cholesterol -A isotherms were studied in the absence and presence of particles and it brought some information about the particle insertion in the monolayers. The DPPC/cholesterol system showed smaller changes in the minimum area per molecule with the increase of PM concentration which indicates the cholesterol acts as an organizer in the monolayer. Dilatational surface rheology data indicated that smaller PM concentrations increase the fluidity of the monolayers while the higher PM concentrations increase their rigidity. Cholesterol enhances the effects provoked by PM. Compressional modulus data obtained from the isotherms showed to be very close to those obtained from the rheological studies performed at higher frequencies. The transferred monolayers, using Langmuir-Blodgett technique, to solid supports were analyzed by Atomic Force Microscopy (AFM) and Fluorescence Lifetime Imaging Microscopy (FLIM) which showed that the particles are deposited together with the film and the DPPC/cholesterol system presents a more homogeneous particle arrangement. FLIM images showed that most likely this arrangement is due to the preference of cholesterol to allocate in regions surround the particles, granting stability to them in the monolayers. The study allowed concluding that PM originate from burned sugar cane leaves has an effect over some features of PS model systems and those properties have the potential to interfere in the perfect performance of these systems in biological environments.
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Růžička, Tomáš. "Tržní příležitosti pro moderní perorální antibiabetika a position nového přípravku." Master's thesis, Vysoká škola ekonomická v Praze, 2010. http://www.nusl.cz/ntk/nusl-77780.
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Diabetes Mellitus is a group of diseases, prevalence and incidence of which is on the rise not only in the Czech Republic, but also worldwide. This diploma work aims to analyze market situation and opportunities for modern oral anti-diabetic drugs. This work also designs suitable positioning for new OADs of Novartis -- Galvus and Eucreas.
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Zhang, Ting. "Studies of DPPA & LPS Monolayers on Aqueous Solutions by Surface Tensiometry and Brewster Angle Microscopy." The Ohio State University, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=osu1417622850.
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Tai, Zhongtian. "Aircraft electrical power system diagnostics, prognostics and health management." Thesis, Cranfield University, 2009. http://dspace.lib.cranfield.ac.uk/handle/1826/9593.
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In recent years, the loads needing electrical power in military aircraft and civil jet
keep increasing, this put huge pressure on the electrical power system (EPS).
As EPS becomes more powerful and complex, its reliability and maintenance
becomes difficult problems to designers, manufacturers and customers. To
improve the mission reliability and reduce life cycle cost, the EPS needs health
management.
This thesis developed a set of generic health management methods for the EPS,
which can monitor system status; diagnose faults/failures in component level
correctly and predict impending faults/failures exactly and predict remaining
useful life of critical components precisely. The writer compared a few
diagnostic and prognostic approaches in detail, and then found suitable ones for
EPS. Then the major components and key parameters needed to be monitored
are obtained, after function hazard analysis and failure modes effects analysis
of EPS. A diagnostic process is applied to EPS using Dynamic Case-based
Reasoning approach, whilst hybrid prognostic methods are suggested to the
system. After that, Diagnostic, Prognostic and Health Management architecture
of EPS is built up in system level based on diagnostic and prognostic process.
Finally, qualitative evaluations of DPHM explain given.
This research is an extension of group design project (GDP) work, the GDP
report is arranged in the Appendix A.
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Shen, Jie. "The role of Decapentaplegic (Dpp) in Drosophila wing development." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2004. http://nbn-resolving.de/urn:nbn:de:swb:14-1102321765343-79763.
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Decapentaplegic (Dpp), a member of the TGF-[Beta] superfamily, acts as a morphogen to direct cell differentiation, determine cell fate and promote cell survival and proliferation in Drosophila wing development. To investigate the role of Dpp in Drosophila wing development, three aspects of the patterning role of Dpp have been analyzed. First, I investigated the cellular responses to Dpp signaling by a loss of function strategy. The consequences of lacking Dpp signal transduction on cell morphology and tissue integrity were analyzed. Second, I investigated whether Dpp signaling is down-stream of Hh signaling to maintain the normal cell segregation at the A/P boundary by clonal analysis. Third, I investigated whether cross talk among the Hh, Dpp and Wg signaling pathways exists and what its relevance for wing patterning is. To investigate the role of Dpp in Drosophila wing development, the general strategies are to look at the phenotypes of loss-of-function and gain-of-function. Mutant clones lacking Dpp signal transduction by knock down Dpp receptor Thick veins (Tkv) do not survive in wing blade due to JNK dependent apoptosis. To get larger mutant clones for analysis, JNK pathway was inhibited by knock down bsk (encodes JNK) in mutant clones lacking Dpp signaling using FLP-FRT system. Clones double mutant for tkv and bsk did not undergo apoptosis, but recovered at very low frequencies compared to sibling clones. Here, I showed that the low recovery of tkv bsk double mutant clones are due to the extrusion of mutant cells. The extrusion of tkv bsk double mutant cells correlated with changes in the actin cytoskeleton and a dramatic loss of the apical microtubule web normally present in these cells. These results suggest that Dpp signaling is required for cell morphogenesis in Drosophila wing development. We propose that Dpp acts as a survival factor in the wing disc epithelium by orchestrating proper cytoskeletal organization and maintaining normal cell-cell contact. Drosophila wing is subdivided into anterior (A) and posterior (P) compartments. This developing into adjacent compartments is crucial for the patterning of Drosophila wing. Previous study has shown that Hedgehog (Hh) signaling is required in A cells to maintain the A/P boundary and is sufficient to specify A type cell sorting. A previous study has in addition implicated the signaling molecule Decapentaplegic (Dpp) in maintaining the A/P boundary. However, this study did not address whether and in which cells, A and/or P, Dpp signal transduction was required to maintain this boundary. Here, I have analyzed the role of components of the Dpp signal transduction pathway and the relation of Dpp and Hh signaling in maintaining the A/P boundary by clonal analysis. I showed that Dpp signaling mediated by the Dpp target gene, T-box protein Optomotor-blind (Omb), is required in A cells, but not in P cells, to maintain the normal position of the A/P boundary. During patterning formation, it is essential for cells to receive precise positional information to pattern the tissue. It has been proposed for a long time that different signaling pathways such as Hedgehog (Hh), Dpp and Wingless (Wg) signaling pathways provide positional information for tissue patterning in an integrated manner. Recently, evidence of interactions between Hh and Dpp as well as Wg and Hh signaling pathways has been reported in Drosophila wing. Here, I have identified additional interactions among Hh, Dpp and Notch/Wg signaling. We propose that the selector gene engrailed, Hh and Dpp signaling interact with each other to regulate target genes expression and thus to pattern the wing along the A/P axis. Further more, I showed that Dpp signaling is also participating in the patterning along the D/V axis by interaction with the selector gene apterous and Notch/Wg signaling.
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Buchholz, Alexander Karl. "DPP: Dual Path PKI for Secure Aircraft Data Communication." Thesis, Virginia Tech, 2013. http://hdl.handle.net/10919/20373.
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Through application of modern technology, aviation systems are becoming more automated and are relying less on antiquated air traffic control (ATC) voice systems. Aircraft are now able to wirelessly broadcast and receive identity and location information using transponder technology. This helps reduce controller workload and allows the aircraft to take more responsibility for maintaining safe separation. However, these systems lack source authentication methods or the ability to check the integrity of message content. This opens the door for hackers to potentially create fraudulent messages or manipulate message content. This thesis presents a solution to handling many of the potential security issues in aircraft data communication. This is accomplished through the implementation of a Dual Path PKI (DPP) design which includes a novel approach to handling certificate revocation through session certificates. DPP defines two authentication protocols, one between aircraft and another between aircraft and ATC, to achieve source authentication. Digital signature technology is utilized to achieve message content and source integrity as well as enable bootstrapping DPP into current ATC systems. DPP employs cutting-edge elliptic curve cryptography (ECC) algorithms to increase performance and reduce overhead.
It is found that the DPP design successfully mitigates several of the cyber security concerns in aircraft and ATC data communications. An implementation of the design shows that anticipated ATC systems can accommodate the additional processing power and bandwidth required by DPP to successfully achieve system integrity and security.
Master of Science
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Oliveira, Sandro de. "Determinação da capacidade antirradicalar de produtos naturais utilizando-se a quimiluminescência do luminol e ensaios fotométricos com radicais estáveis." Universidade de São Paulo, 2011. http://www.teses.usp.br/teses/disponiveis/46/46136/tde-05122011-114158/.
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Os organismos vivos estão expostos à ação oxidativa de espécies reativas de oxigênio (ERO), causando uma série de doenças degenerativas como câncer, aterosclerose, diabetes, artrite e doenças do coração. Estudos têm demonstrado que o consumo de substâncias antioxidantes na dieta diária podem prevenir estes processos oxidativos que provocam o envelhecimento precoce do organismo. Nas últimas décadas tem se destacado o interesse em encontrar antioxidantes naturais para o emprego em produtos alimentícios ou farmacêuticos, com a finalidade de substituir antioxidantes sintéticos, os quais apresentam restrições devido ao seu potencial tóxico. Nesse trabalho, são comparados os resultados de medidas da capacidade antirradicalar de vários derivados fenólicos incluindo produtos naturais obtidos com os ensaios utilizando o radical estável DPPH• e o cátion radical ABTS•+, que apresentam vantagens em relação à simplicidade do método analítico e facilidade na coleta de dados, além da reprodutibilidade dos resultados. Além disso, desenvolveu-se um ensaio com DPPH• para avaliar a capacidade antirradicalar de compostos fenólicos em meio ácido, hidroalcoólico e tamponado, para possibilitar a obtenção de valores da capacidade antirradicalar de flavonoides e compostos análogos em meio aquoso em diferentes estados de ionização. Também, foi utilizado o ensaio quimiluminescente com luminol/hemina/H2O2, desenvolvido pelo nosso grupo de pesquisa, para a determinação da capacidade antirradicalar de extratos, fases e frações de Baccharis regnelli e proposto o novo parâmetro \"Porcentagem de Trolox\" para expressar adequadamente esta capacidade em misturas complexas. A sensibilidade do ensaio luminol comprovou ser maior que a de outros métodos e adequado para medir a capacidade antirradicalar de misturas complexas de produtos naturais, auxiliando no isolamento de novas substâncias com atividade antirradicalar.Living organisms are exposed to the oxidative action of reactive oxygen species (ROS), causing a series of degenerative diseases such as cancer, atherosclerosis, diabetes, arthritis and heart disease. Studies have shown that consumption of antioxidant substances in the daily diet can prevent these oxidative processes that cause premature aging of the organism. Much attention has been paid in the last decades on the discovery of new natural antioxidants for its use in food or pharmaceutical industry, with the aim of replace synthetic antioxidants, which have restrictions due to their toxic potential. In this study, we compared the results from antiradical capacity determinations of several phenolic derivatives including natural products obtained by two different assays. One of them utilizes the stable radical DPPH• and the other the radical cation ABTS•+ as reagents and both have the advantage of a simple analytical method and ease in data collection as well as high data reproducibility. Furthermore, we have developed a method with DPPH• for the evaluation of the antirradicalar capacity of phenolic compounds in acid and buffered hydroalcoholic media, in order to facilitate the determination of the antiradical capacity of flavonoids and similar compounds in aqueous ambient and to allow differentiation between the capacity of different ionization states of these derivatives. Finally the chemiluminescent luminol/hemin/H2O2 assay, developed by our research group, has been utilized for the determination of the antiradical capacity of extracts, phases and fractions of Baccharis regnelli and the new parameter \"Trolox Percentage\" is being proposed to adequately express the antiradical capacity of complex mixtures. The sensibility of the luminol assay has been found to be higher than that of other methods and is shown to be suitable for the determination of antiradical activity parameters of complex natural product mixtures, contributing to the isolation of new substances with antiradical activity.
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HAMAJIMA, NOBUYUKI, KENJI WAKAI, GUANG YIN, RIEKO OKADA, SAYO KAWAI, EMI MORITA, ERINA KOYAMA, et al. "DPP4 Genetic Variants Influence Baseline Prostate-Specific Antigen Levels: The J-MICC Study." Nagoya University School of Medicine, 2013. http://hdl.handle.net/2237/17603.
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Janovik, Vanessa. "AVALIAÇÃO QUÍMICA E ATIVIDADE ANTIOXIDANTE DAS CASCAS E TRITERPENÓIDES OBTIDOS DE CARINIANA DOMESTICA (MART) MIERS." Universidade Federal de Santa Maria, 2011. http://repositorio.ufsm.br/handle/1/6040.
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Coordenação de Aperfeiçoamento de Pessoal de Nível SuperiorThe Lecythidaceae family consists of about 230 species, classified in some 10 genera. The species Cariniana domestica (Mart) Miers is one of several Jequitibá species, the oldest and millenary trees from Brazil. The present work developed studies with the aim of characterize the species when concerning to chemical aspects, in order to contribute to the knowledge improvement about Lecythidadeae family. The barks of C. domestica were collected in Tangará da Serra-MS. Exsiccate was archived as voucher specimen in the herbarium of Department of Biology at UFSM (SMDB 11818). Plant material was dried, crushed and powdered. The powder was submitted to hidroalcoolic maceration (7:3, v/v) and concentrated under reduced pressure. The remained aqueous extract was partitioned to obtain the fractions FCH2Cl2, F-AcOEt e F-BuOH. Chromatographic procedures led to the isolation of phytosterols (β-sitosterol + stigmasterol) and pentacyclic triterpenes (lupeol + β- amyrin), which were identified by means of spectroscopic (1H-NMR and 13C-NMR) and chromatographic (GC/MS and HPLC) methods. Additionally, the antioxidant capacity was evaluated by measuring its scavenging ability on DPPH and also using TBARS assay. Contents of total polyphenolic and flavonoid were measured as well as a chromatographic profile searching for phenolic substances was determined.. From F-CH2Cl2, DPPH assay revealed high scavenging ability with IC50 values that ranged from 6.5 ± 0.81 to 19.5 ± 1.32 μg/mL. IC50 values obtained with TBARS assay ranged from 11.11 ± 0.85 to 44.5 ± 2.31 μg/mL. Polyphenolic contents varied from 54.6 ± 0.33 to 309.3 ± 2.73 mg/g. Total flavonoid and condensed tannin contents varied from 12.0 ± 0.12 to 14.18 ± 0.1 and 131 ± 0.03 to 149.7 ± 0.22, respectively. HPLC analysis revealed the presence of gallic, caffeic and chlorogenic acids, as well as the flavonoids rutin, quercetin and kaempferol. The carotenoids lycopene and β- carotene were identified in dichloromethane fraction. The results revealed that the species C. domestica achieves antioxidant properties and the compounds identified for the first time for this species can be related to its popular uses.
A família Lecythidaceae consiste em cerca de 230 espécies, classificada em 10 gêneros. A espécie Cariniana domestica (Mart) Miers é uma das diversas espécies de Jequitibá, as árvores milenares mais antigas do Brasil. O presente estudo teve o objetivo de caracterizar quimicamente a espécie, visando contribuir para um maior conhecimento sobre a família Lecythidaceae. As cascas de C. domestica foram coletadas no município de Tangará da Serra-MS e o material foi catalogado sob o registro SMDB 11818 no departamento de Biologia da UFSM. O material vegetal foi seco, triturado e moído. O pó obtido foi submetido à maceração hidroalcóolica (7:3, v/v), seguindo-se de concentração em evaporador rotatório. A partição do extrato aquoso remanescente originou as frações F-CH2Cl2, F-AcOEt e F-BuOH. Os procedimentos cromatográficos de isolamento levaram à obtenção do fitoesteróis (β-sitosterol + estigmasterol) e triterpenos pentacíclicos (lupeol + β-amirina), os quais foram identificados por métodos espectroscópicos (1H-RMN e 13C-RMN) e cromatográficos (CG/EM e CLAE). Adicionalmente, foi avaliada a capacidade antioxidante frente ao radical DPPH, bem como utilizando o método do TBARS. Foram ainda realizadas dosagens investigativas quanto ao teor de polifenóis totais e flavonóides e um perfil cromatográfico para identificação de alguns compostos fenólicos também foi traçado. Os ensaios com o radical DPPH revelaram elevada capacidade seqüestradora de radicais livres, sendo que os valores de IC50 obtidos variaram de 6,5 ± 0,81 a 19,5 ± 1,32 μg/mL. No ensaio do TBARS, os valores de IC50 obtidos variaram de 11,11 ± 0,85 a 44,5 ± 2,31. A determinação de polifenóis totais revelou um teor variável de 54,6 ± 0,33 a 309,3 ± 2,73 mg/g. As determinações de flavonóides totais e taninos condensados variaram de 12,0 ± 0,12 a 14,18 ± 0,1 mg/g e 131 ± 0,03 a 149,7 ± 0,22, respectivamente. A análise por CLAE revelou a presença dos ácidos gálico, caféico e clorogênico, além dos flavonóides rutina, quercetina e campferol. Na fração diclorometano foram identificados os carotenóides licopeno e β-caroteno. Os resultados obtidos demonstram que a espécie C. domestica apresenta propriedades antioxidantes e os compostos identificados pela primeira vez para esta espécie podem estar relacionados com seus usos populares.
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Raudonis, Raimondas. "Efektyviosios skysčių chromatografijos - pokolonėlinės reakcijos metodo vystymas antioksidantinio aktyvumo nustatymui." Master's thesis, Lithuanian Academic Libraries Network (LABT), 2008. http://vddb.library.lt/obj/LT-eLABa-0001:E.02~2008~D_20080616_100532-09677.
Full textAbstract:
Didelis dėmesys skiriamas natūralių antioksidantų paieškai ir įvertinimui augalinės kilmės vaistinėse ir maistinėse žaliavose. Mokslinių tyrimų objektais yra didelis skaičius augalų rūšių, ekstraktų, maisto papildų ir vaistinių preparatų. Tiriamųjų darbų našumas ir informatyvumas, be abejonės, priklauso nuo pasirinktų metodų tinkamumo, jautrumo ir efektyvumo. Darbo tikslas yra išvystyti bei įteisinti pokolonėlinę ESC-DPPH metodiką ir ją pritaikyti laisvuosius radikalus surišančių žinomų ir nežinomų junginių, esančių vaistinėje augalinėje žaliavoje, antioksidantinio aktyvumo įvertinimui. ESC išskirstyti junginiai nustatomi UV detektoriumi 275 nm ilgio bangoje; mobili fazė su analitėmis per maišymo trišakį tiekiama į reakcijos kilpą, kur 0,4 ml/min tėkmės greičiu paduodamas DPPH tirpalas. Reakcijos kilpa sujungta su UV/Vis tipo detektoriumi, matuojančiu pratekančio tirpalo absorbciją esant 520 nm bangos ilgiui. Nustatyta, jog Crataegus monogyna lapuose vyraujantis flavonoidas viteksino ramnozidas nepasižymi antioksidantiniu aktyvumu. Reikšmingiausias antioksidantas C. monogyna lapuose ir žieduose yra chlorogeno rūgštis. Didžiausiu antioksidantiniu aktyvumu Origanum vulgare augalinėje žolėje pasižymi rozmarino rūgštis. Achillea millefolium ekstraktuose identifikuotos šios analitės, turinčios radikalus surišantį aktyvumą: chlorogeno rūgštis, luteolin-7-O-gliukozidas, rutinas ir luteolinas.The most important attention is paid to the search of natural antioxidants and their evaluation in medicinal and food raw materials of plant origin. A number of plants, their extacts, food products and medicinal preparations appear to be objects of scientific research. Effectiveness and informative character of research, undoubtedly, depend on relevance, sensitivity and efficiency of the methods chosen. Aim of this work is development and validation of post column HPLC-DPPH method as well as its application in antioxidant activity evaluation of known and unknown compounds fixing free radicals and existing in medicinal plant raw materials. HPLC separated compounds are identified at wave length of 275 nm and then the mobile phase with analytes flows by mixing tee to the reaction coil, where DPPH reagent solution is supplied. The solution flow rate – 0,4 ml/min. The reaction coil is connected with UV/Vis type detector, which measures absorption of flowing solution at wave length of 520 nm. It was dermined that vitexin rhamnoside, the dominant compound in the leaves of Crataegus monogyna, is not significant radical sacavenger. The most active antioxidant in leaves and the flowers of C. monogyna is chlorogenic acid. The most active antioxidant in Origanum vulgare raw materials is rosmarinic acid. Identified analytes in the extracts of Achillea millefolium that possessed radical scavenging properties were chlorogenic acid, luteolin-7-O-glucoside, rutin and luteolin.
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Dalgê, Jéssica Jamila. "Estudo da capacidade antioxidante, antimicrobiana e anti-hemolítica do gengibre (Zingiber offinale)." Universidade de São Paulo, 2014. http://www.teses.usp.br/teses/disponiveis/74/74132/tde-08092015-083147/.
Full textAbstract:
O presente estudo teve como objetivo determinar a capacidade antioxidante, antimicrobiana e anti-hemolítica do gengibre (Zingiber officinale) utilizando diferentes solventes extratores. Para tal, rasuras secas de gengibre foram trituradas e usadas na proporção 1:50 (p/v) nas quatro diferentes extrações: água, etanol (70%), acetona/ácido acético (70%/2%) ou acetona (70%). Após centrifugação, o extrato foi utilizado pra determinar o conteúdo de compostos fenólicos por Folin-Ciocalteau e ação sobre os radicais ABTS+. e DPPH.. Foi selecionado o melhor solvente extrator pelas propriedades antioxidantes e facilidade de sua remoção da matriz. Este extrato foi submetido à rotaevaporaçao, liofilizaçao e ressuspenção em tampão fosfato salino (PBS) e, então, utilizado nos estudos biológicos de captura de NO, ação antioxidante sobre hemólise induzida e ação sobre o crescimento de S. aureus. Os resultados foram expressos como média e desvio padrão. Para análise estatística empregou o software Minitab® com comparação entre grupos por ANOVA, diferenças significativas por Tukey e P < 0,05. O extrato de gengibre obtido em acetona apresentou maior conteúdo de compostos fenólicos (8,52 ± 1,24 mg equivalente de ácido gálico/g de gengibre). O extrato acetona apresentou menor valor de EC50 e maior ação antioxidante mediantes o ensaio com ABTS+., sendo respectivamente 0,07 ± 0,01 mg de massa seca do extrato/mL de ensaio e 10,93 ± 0,79 mg equivalentes de trolox (ET)/g de gengibre, sem diferença significativa com os valores obtidos nos extratos etanol e acetona/ácido. No ensaio do DPPH., o extrato acetona apresentou menor valor de EC50 (0,15 ± 0,01 mg de massa seca de extrato/mL de ensaio) e maior ação antioxidante (8,35 ± 0,60 mg ET/g de gengibre), sem diferença significativa com relação ao extrato etanólico. Dentre todos os ensaios, a extração em água apresentou resultados menos satisfatórios. A acetona foi selecionada como solvente extrator dos componentes do gengibre para os estudos biológicos. O extrato de gengibre (17,25 mg de massa seca/mL) inibiu 50% da formação de produtos no ensaio de captura de NO, valor similar ao obtido pela presença do antioxidante ácido gálico. Concentrações menores de extrato também agiram sobre o NO, sendo que 1,25 mg/mL refletiu em 33% de inibição. A hemólise foi evitada em 100% pelo extrato de gengibre em concentrações acima de 113 µg de massa seca de extrato/mL, resultado similar ao encontrado no ensaio contendo ácido ascórbico. A lise das hemácias foi evitada em 44% na presença de extrato 57 µg/mL. O extrato de gengibre não apresentou ação antimicrobiana sobre S. aureus. Conclui-se o extrato de gengibre, nas condições deste estudo, apresenta atividade antioxidante sobre ABTS+. e DPPH.; bem como sobre sistemas biológicos modelos como na captura de NO e lise de membrana celular.The aim of this study was to determinate antioxidant capacity, antimicrobial activity and anti hemolytic action of ginger (Zingiber officinale) extract obtained by different solvents. For this purpose, dried ginger flakes were powdered and used in ratio 1:50 (w/v) in the four different extractions: water, ethanol (70%), acetone/acetic acid (70%/2%) and acetone (70%). The extract was centrifuged and used for phenolic compounds determination by Folin-Ciocalteau and action on ABTS+. and DPPH. radicals. The best extractor solvent was selected by its antioxidant properties and easier elimination from the matrix. The select extract was submitted on evaporation and lyophilization, and subsequent re-suspension on phosphate buffer saline (PBS). Then, this suspension was used in biologic studies as NO scavenging, antioxidant action on induced hemolysis and effect on S. aureus growth. The values were express as mean and standard deviation. Statistical analysis carried out by Minitab® using ANOVA and Tukey to p< 0.05. Acetone ginger extract showed highest value of phenolic content (8.52 ± 1.24 mg galic acid equivalent /g of ginger). The acetone extract showed the lowest EC50 value and higher antioxidant action on ABTS+., 0.07 ± 0.01 mg of dry weight of the extract/mL of assay and 10.93 ± 0.79 mg trolox equivalents (TE)/g of ginger, respectively. These values did not show significant difference in relation to ethanol and acetone/acid extracts. For DPPH. assay, acetone extract showed lower value of EC50 (0.15 ± 0.01 mg dry weight of extract/mL assay) and higher antioxidant action (8.35 ± 0.60 mg TE/g of ginger), without significant difference in relation to ethanolic extract. Among all extracts, aqueous extract showed lesser satisfactory results. Acetone extract was selected for biological assays. Ginger extract (17.25 mg of dry weigth/mL) inhibited 50% of products formation on NO scavenging assay, similarly to galic acid results. Lower extract concentrations as 1.25 mg/mL inhibited 33% of NO. The 100% of hemolysis prevention was obtained by concentrations of ginger extract higher than 113 µg of dry weight of extract/mL of assay. Similar result was observed by presence of ascorbic acid. Erythrocytes lysis was avoided in 44% by 57 µg/mL of ginger extract. Ginger extract did not show antimicrobial action on S. aureus. In conclusion, ginger extract, in present conditions, showed antioxidant action on ABTS+. and DPPH. assays and in biological model systems as in NO scavenging assay and cell membrane lysis.
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Korkmaz, Filiz. "Biophysical Studies Of Progesterone-model Membrane Interactions." Master's thesis, METU, 2003. http://etd.lib.metu.edu.tr/upload/4/1116060/index.pdf.
Full textAbstract:
Interactions of progesterone with zwitterionic dipalmitoyl
phosphotidylcholine (DPPC) multilamellar liposomes (MLVs) were investigated as a
function of temperature and progesterone concentration by using three non-invasive
techniques of Fourier transform infrared (FTIR) spectroscopy, turbidity at 440 nm
and differential scanning calorimetry (DSC). The results show that 1mol% of progesterone does not induce a significant
change in the shape of thermotropic profile of DPPC. However as progesterone
concentration increases, the main transition temperature decreases and phase
transition curve broadens. Higher concentrations (12, 18 and 24mol%) also
decreased the transition temperature but not as significantly as lower concentrations.
The characteristic pretransition of DPPC was completely disappeared upon the
addition of progesterone. Progesterone disorders the phospholipid membranes in a
concentration dependent manner. Furthermore, low concentrations of progesterone
(3, 6 and 9mol%) increase the fluidity of the system but high concentrations (12, 18
and 24mol%) stabilize the membranes by decreasing the mobility of the acyl chains.
The opposite effect of progesterone on membrane dynamics of low and high
concentrations was also supported by turbidity studies at 440 nm.
DSC peaks broaden and shift to lower temperature degrees with increasing
concentrations up to 9mol% of progesterone. At 6 and 12mol% of progesterone, the
curve contains more than one peak. This indicates the existence of phase separation.
The pretransition of liposomes was eliminated for all samples containing
progesterone.
Analysis of C=O stretching bond in FTIR spectroscopy showed that
progesterone does not make any hydrogen bonds with the interfacial region of DPPC
liposomes, instead it induces free carbonyl groups in the system. Ester groups were
found to be disordered by the addition of progesterone and the effect is profound
with 6 and 9mol% concentrations. The head group of liposomes were found to make hydrogen bonding in the
vicinity of 3mol% of progesterone in both phases and of 6mol% of progesterone in
liquid crystalline phase by infrared spectroscopy of PO-
2 stretching mode. This
hydrogen bonding is made either with the hydroxyl group of progesterone or with the
water molecules around the head group. With other concentrations of progesterone,
there is no evidence of hydrogen bond formation.
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Calhoun, Robert Lee. "Electrochemisty and electrogenerated chemiluminescence of Ru(phen)₂dppz(BF₄)₂ both free and intercalated into DNA." Thesis, 2007. http://hdl.handle.net/2152/3006.
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Tang, Hung-Kuan, and 唐弘寬. "Biochemical Characterization of Dipeptidyl Peptidase IV (DPP-IV) and DPP9." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/81400866916411761559.
Full textAbstract:
博士國立中央大學
化學工程與材料工程研究所
97
The family of prolyl dipeptidases has attracted extensive investigation in recent years because of their unique ability to cleave the peptide bond after a penultimate proline residue. It includes dipeptidyl peptidase IV (DPP-IV, EC 3.4.14.5), FAP (fibroblast activation protein), DPP2 (E.C. 3.4.14.2), DPP8 and DPP9. DPP-IV is the most extensively studied, and the functions for other members are not known so far. DPP9 and DPP8 are highly homologous proteases with 58% sequence identity at the amino acid level. Both the structure and function of these two proteases are not known. In this thesis, we first characterized the biochemical property of DPP9 including its enzymatic activity, quaternary structure, substrate specificity and pH optimum. DPP9 was expressed and purified from the baculovirus-infected insect cells using Strep•TactinTM purification system. The yield is significantly higher than what was reported in the literature. DPP9 has similar enzymatic activity, substrate specificity and pH optimum as DPP8. Both of them are homodimeric. Single site mutation at the C-terminal loop (F842A), one of the dimer interfaces, results in dimeric DPP9 with little enzymatic activity. The results indicate that the interaction mode of dimerization is similar to that of DPP8, reported previously from our lab. Therefore, the biochemical property of DPP9 we discovered so far is almost identical to that of DPP8. We speculate that DPP9 and DPP8 carry out overlapping functions in vivo. We have also determined the expression profile of DPP9. DPP9 is ubiquitously expressed in different cell types including fibroblasts, epithelial and blood cells. Surprisingly, contrary to previous report, we found that the expression levels of DPP8 and DPP9 do not change upon the activation of T-cells such as PBMC and Jurkat cells. Because DPP8 and DPP9 are ubiquitously expressed, whether they involve in immunological function as speculated awaits further studies. The characterization of DPP9 reported here lays the foundation for revealing its function in the future DPP-IV is a validated drug target for human type II diabetes. DPP-IV inhibitors without DPP8/9 inhibitory activity have been sought because a possible association was reported between a “DPP8/9 inhibitor” and severe toxicity in animals. However, at present, it is not known whether the observed toxicity is associated with DPP8/9 inhibition, or an off-target effect induced by the compound. We investigated whether the inhibition of DPP8/9 is the cause of the severe toxicity in animals using a very potent and selective DPP8/9 inhibitor with different pharmacophore, 1G244. By Ki measurement, 1G244 is 15- and 8-fold more potent against DPP8 and DPP9, respectively, than the “DPP8/9 inhibitor”. Strikingly, the “DPP8/9 inhibitor” does not penetrate the plasma membrane but remains outside the cells, whereas 1G244 readily enters the cells, even at low doses. By repeatedly exposing Strague-Dawley rats to 1G244 by intravenous injection for a period of 14 days, we observed no significant toxicological symptoms associated with 1G244. Blood and serum chemistry parameters were all within the normal ranges for the treated animals. Because of the high potency, good membrane penetration and adequate tissue distribution of 1G244, the mild symptoms observed are probably associated with DPP8/9 inhibition. Our results demonstrate that there is no direct causal effect of DPP8/9 inhibition with toxicity in animals. Finally, we have examined the contribution of the propeller loop to the enzymatic activity and quaternary structure of DPP9 and DPP-IV. The propeller loop is one of the two dimer interfaces and its function for the structure and activity of prolyl dipeptidase family is not known. Because the crystal structure of DPP9 has not been resolved, we have identified the sequence corresponding to the propeller loop of DPP9 based on the sequence alignment with other members of prolyl dipeptidases, and computer modeling of DPP8 reported in the literature. The conserved residues or the corresponding residues whose mutations have drastic effects on DPP-IV structure and activity were chosen to be mutated. The mutant proteins were expressed and purified from insect cells. For DPP9, five mutations located on the propeller loop were generated, which include a complete deletion of the propeller loop (DEL), V319A, E325A, K328A and Y334A. Among them, the dimeric structure and enzymatic activity of V319A, E325A and K328A mutant proteins were similar to those of wild type DPP9. In contrast, Y334A and DEL fail to disrupt DPP9 dimers to monomers. However, the mutant dimers are inactive with kcat significantly decreased and Km increased. Interestingly, differential effects on the structure and activity of DPP-IV were discovered with mutations on the propeller loop. Based on the crystal structure of DPP-IV, we have identified two groups of residues on the propeller loop that are involved in inter-molecular and intra-molecular interactions, Y248 involved in intermolecular interaction, and Y238 and Y256 involved in intramolecular interaction. We have introduced single site mutation to these residues resulting in Y248F, Y248A, Y248T, Y238A and Y256A, respectively. We also generated a deletion mutation, called Del, by deleting the whole propeller loop. We demonstrated that phenyl group of Y248 is essential for dimer formation. Lack of phenyl group, such as Y248T, Y248A and Del, results in monomeric DPP-IVs with very low or no activities. Specifically, Y248A and deletion mutants result in monomers with no activity detectable, while monomeric Y248T has a low kcat and an unchanged Km. Difference on Km effects suggests that the hydroxyl group might be important for the integrity of the substrate binding pocket. Y238A and Y256A mutations result in a mixture of monomers and dimers. Intriguingly, the monomers of Y238A and Y256A were fully active as the dimers. This is drastically different from all the monomeric mutations we generated previously. Further work will be required to fully understand the underlying mechanism of these active monomeric DPP-IVs. In summary, our results demonstrate that the propeller loop exerts differential effect on the structure and activity of DPP-IV and DPP9. Understanding how propeller loop affects the structure and activity of prolyl dipeptidases will help the understanding of the biogenesis and folding of homomeric proteins in the future.
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NHANG, YONG-JI, and 張永佶. "含磷雙牙配子VIB金屬羰基錯合物,Cr(CO)��(dppm)､M��(CO)��(dpph)(M=Cr,Mo)､Mo��(CO)��(dppo)和Cr(CO)��(BDPH)之合成及結構研究." Thesis, 1992. http://ndltd.ncl.edu.tw/handle/45813905265453833384.
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Kilfoil, Maria. "p2sH NMR studies of the effect of the DPPC/DPPG ratio on bilayer properties in the presence of Cap2sp+s /." 1997.
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LI, JIA-QING, and 李家慶. "含磷雙牙團配子VIB金屬羰基配位錯合物-W(CO)��(BDPH),W��(CO)��-(u-dpph),MO��(CO)��(μ-dppd)及W��(CO)��(μ-dppd)的結構研究." Thesis, 1992. http://ndltd.ncl.edu.tw/handle/90433723381023872398.
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Ku, Hui-Chun, and 辜惠君. "The cardioprotective effects of DPP4 deficiency." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/52006893107154725210.
Full textAbstract:
博士國立臺灣大學
藥理學研究所
100
Dipeptidyl peptidase-4 (DPP4) enzyme inhibition has been reported to increase plasma glucagon-like peptide-1 (GLP-1) level for controlling postprandial glucose concentration. Both DPP4 inhibitors and GLP-1 analogue have been approved as antihyperglycemic agents in the treatment of diabetes. In addition to the insulinotropic effect, GLP-1 signaling was discovered for the improvement of cardiovascular disease. We examined whether genetic mutation of DPP4 influence cardiac response in both animal model experiments and cell studies. Adult Fischer 344 (wild type) and DchcHsd-DPP IV (served as DPP4 deficiency) rats were used. DPP4 activity of DPP4-deficient rats is about one third of that in wild-type rats. Animal model experiments of endotoxemia and myocardial infarction were performed and compared in two kinds of rats. Cardiac function was assessed by pressure-volume loop monitoring. In some studies, GLP-1 analogue (exendin-4) or receptor antagonist (exendin-(9-39)) were used to identify the signaling of the protective effect. The blood plasma samples were collected and the hearts were harvested at the end of the experimental model. Adult cardiomyocyte was also isolated in two kinds of rats, and the effects of H2O2 induced ROS stress were compared. Cell viability, ROS staining, and proapoptotic signaling were executed to determine the response to H2O2. Endotoxemia was induced by the administration of lipopolysaccharide (LPS, 10 mg/kg, i.v.), and all the experiments were performed after 4 h of treatment. LPS-induced suppression of cardiovascular function in wild-type rats was associated with a significant reduction in cardiac cAMP level, phosphorylation of phospholamban, and attenuation of aortic contractile response to phenylephrine. DPP4-deficient rats had better preservation of cardiovascular function than wild-type rats during endotoxemia, which was correlated with a more prominent elevation of GLP-1 signaling. These findings coincided with the pretreatment of GLP-1 analogue, exendin-4, where the deterioration of cardiovascular function during endotoxemia was significantly reversed in wild-type rats. Furthermore, the benefit of DPP4 deficiency or GLP-1 analogue not only preserved cardiovascular function but also alleviated multiple organ injury and improved survival rate during endotoxemia. In brief, this study demonstrated that the resistance to LPS in DPP4-deficient rats seems to be derived from the higher GLP-1 production, while exendin-4 exerts protective effect in endotoxemia. For the myocardial infarction experimental models, rats were subjected to 45 min of coronary artery occlusion, and followed by reperfusion for 2 h. As compared to wild-type rats, after ischemia/reperfusion (I/R), DPP4-deficient rats had better cardiac performance in association with less infarct size and cardiac injury markers (LDH, ANP, and BNP), which could be attenuated by exendin-(9–39), a GLP-1 receptor antagonist. Exendin-(9–39) could diminish the increased phosphorylation levels of myocardial AKT and GSK-3β as well as the higher expression of GLUT4 in post-infarcted DPP4-deficient rats. However, exendin-(9–39) could not completely abrogate the less infarct size in DPP4-deficient rats as compared with that in wild-type rats, implicating the involvement of GLP-1 receptor-independent pathway. Accordingly, this study demonstrated that the benefit of cardiac protective action against I/R injury in DPP4-deficient rats, which is mediated through both GLP-1 receptor-dependent and receptor-independent mechanisms. DPP4-deficient rats show resistance to endotoxemia and ischemia/reperfusion. However, the decrease of DPP4 activity simply augmented the GLP-1 signaling or that such decrease resulted in a functional change or induced new signaling pathways remain unclear. With above reasons, we compared two kinds of cardiomyocytes under oxidative stress induced by H2O2. Cardiomyocytes were isolated from two kinds of rats. The effect of H2O2-induced ROS stress was performed in the presence or absence of GLP-1. DPP4-deficient cardiomyocytes were found to be resistant to H2O2-induced cell death via diminishing ROS level, Bax/Bcl-2 ratio, and caspase-3 activity. GLP-1 was also shown to decrease H2O2-induced cell death in wild-type cardiomyocytes via increasing the phosphorylation of AKT, which was abolished by exendin-(9–39), suggesting the importance of GLP-1 receptor dependent pathway. However, GLP-1 did not further increase phosphorylation of AKT against H2O2-induced stress in DPP4-deficient cardiomyocyte, indicating a crucial role of GLP-1-independent mechanism in these events. These several studies suggest that higher GLP-1 concentration in DPP4 mutant rats may contribute to the resistance to LPS and myocardial infarction. The protective effect is associated with both GLP-1 receptor -dependent and -independent pathway. The receptor dependent pathway is via increasing phosphorylation of AKT to ameliorate cardiac injury. In addition to the blood glucose controlling effect, GLP-1 receptor agonist or DPP4 inhibitor may exert cardioprotective effect in diabetes, and possibly be used as a preventive or even as a novel therapeutic agent in septic shock and myocardial infarction.
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Watts, Joel Christopher. "Characterization of Shadoo and DPPX: Two Proteins of Potential Relevance to Prion Biology." Thesis, 2008. http://hdl.handle.net/1807/11275.
Full textAbstract:
Prion diseases are fatal neurodegenerative disorders of humans and animals. The prion hypothesis states that PrPSc, a misfolded conformational isoform of the cellular prion protein (PrPC), is the sole component of the infectious particle. Many open questions exist in prion biology including the cellular role of PrPC, the potential involvement of auxiliary factors in prion replication, and the mechanism of PrPSc-induced toxicity in prion disease. The identification of novel prion-like proteins and authentic in vivo prion protein-interacting proteins would certainly assist the process of demystifying these unsolved mysteries. Accordingly, two newly-identified proteins with potential relevance to prion protein biology, Shadoo and DPPX, were selected for biochemical and functional characterization. Shadoo, a hypothetical prion-like protein, is revealed as being a glycoprotein which possesses many overlapping properties with PrPC including neuronal expression, C1-like endoproteolytic processing, and the ability to protect against apoptotic stimuli in cerebellar neurons. Shadoo loosely resembles the disordered N-terminal domain of PrPC and consistent with this notion, Shadoo appears to lack a well-defined structure. Remarkably, Shadoo levels in the brains of mice with clinical prion disease are significantly decreased suggesting that Shadoo may be inherently linked to prion replication or prion disease pathogenesis. These experiments define Shadoo as the third member of the prion protein family and, because of its functional similarities to PrPC, Shadoo may be a useful tool for deciphering the in vivo function of PrPC. DPPX, a neuronal type II transmembrane protein, is demonstrated to be the first protein capable of interacting with all three members of the prion protein family (PrPC, Doppel, and Shadoo) in vivo. Complex formation between prion proteins and DPPX appears to be mediated by multiple binding sites. When coupled with high levels of DPPX expression in cerebellar granular neurons, DPPX is a strong candidate for mediating phenotypic interactions between prion proteins in cerebellar cells. Thus, Shadoo and DPPX comprise two new entry points for studying prion proteins. Further investigation of the roles of Shadoo and DPPX in both the cell biology of prion proteins and prion disease may yield important clues to these enigmatic topics.
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余信德. "Interfacial Properties of Mixed DPPC/Protein Monolayers." Thesis, 1997. http://ndltd.ncl.edu.tw/handle/35140218342427995646.
Full textAbstract:
碩士國立成功大學
化學工程研究所
85
The hysteresis behavior of air/protein solution interface with or without DPPC monolayer is studied. The air/protein solution interface shows reproducible hysteresis behavior, which implies that both γ-globulin and lysozyme molecules have good respreading ability, and also indicates the characteristics of the slow desorption and fast readsorption behavior of proteins. As tile DPPC monolayer is spread on the air/protein solution interface, the surface pressure jumps immediately and slowly decreases to reach an equilibrium value. The typical collapse behavior of DPPC monolayer is observed during the first compression-expansion cycle of the interface, but is less significant during the subsequent cycles. Due to the fast readsorption rate of protein and poor respreading ability of DPPC, the hysteresis behavior of air/protein solution interface with DPPC monolayer at 37℃ after three compression-expansion cycles is similar to that obtained for the air/protein solution interface without DPPC monolayer. However, at 25℃, the hysteresis behavior after three cycles still shows the characteristics of DPPC monolayer. Moreover, if the . DPPC monolayer is spread first and then the γ-globulin monolayer is spead, there is the collapse characteristics of DPPC monolayer during the first compression-expansion cycle, and die change of hysteresis area is smaller compared with that obtained by spreading γ-globulin monolayer before DPPC monolayer. However, the characteristics of DPPC monolayer is still more significant at 25℃ than at 37℃.
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Chou, Tzung-Han, and 周宗翰. "Molecular Interactions of Mixed Monolayers Containing DPPC." Thesis, 1999. http://ndltd.ncl.edu.tw/handle/70618641096228772150.
Full textAbstract:
碩士國立成功大學
化學工程學系
87
This study investigated the behavior of mixed DPPC/cholesterol monolayers and mixed DPPC/DHDP monolayers at the air/liquid interface at 37 . For DPPC/cholesterol mixed system at the air/water interface, the measurements of surface pressure-area per molecule (P-A) isotherms and relaxation curves were carried out. In the thermodynamic analysis of the mixed monolayers, the areas of monolayers exhibited negative deviations from the ideal values at all compositions for lower surface pressures. However, at higher surface pressures, distinctively positive deviations from ideality were observed at lower DPPC contents. Excess free energies of mixing had been calculated and the most stable state of the mixed monolayer with xDPPC = 0.5 or 0.6 was found. Compressibilities of the mixed monolayers indicate that the addition of cholesterol increased the fluidity of a DPPC monolayer. Moreover, the relaxation kinetics of the mixed monolayers was investigated by measuring the surface area as a function of time at a constant surface pressure of 40 mN/m. It was shown that the relaxation processes could be described by the models considering nucleation and growth mechanisms. The mixed monolayer behavior of DPPC and DHDP on water and phosphate buffer subphases were investigated from the measurements of P-A isotherms. The P-A isotherms indicate that the two components were miscible in the condensed and collapse states at the interface. The miscibility and nonideality of the mixed monolayers were examined by calculating the excess area as a function of composition, and deviations from ideality were observed, which suggests that the existence of attractive interactions between DPPC and DHDP molecules in the mixed monolayers on both subphases. Nevertheless, the presence of ions in the subphase may disturb molecular interactions and packing in the mixed monolayers, resulting in more expanded monolayers and complicated excess area behavior. Furthermore, the excess free energies of mixing and free energies of mixing were evaluated from the isotherms and the most stable state of the mixed monolayers on a water subphase was found with xDHDP = 0.5 or 0.6. However, it was shown that the mixed monolayers were more stable on a water subphase than on the phosphate buffer subphase.
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Wang, Hong-Yu, and 王宏榆. "Microstructure of Mixed DPPC/PA Monolayer Observed by AFM." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/34984169513918620131.
Full textAbstract:
碩士國立宜蘭大學
生物機電工程學系碩士班
104
The objective of this research is to study the stability of DPPC/PA monolayers at air-water interface. DPPC and PA are the main compositions of human pulmonary surfactants that contribute to the surface tension-lowering ability of pulmonary surfactants. Previous studies indicated that DPPC alone cannot substitute natural pulmonary surfactant to restore the normal function of a lung because the DPPC monolayer is unstable over its dynamic compression–expansion cycle. A LB film balance system was utilized to monitor the dynamic surface pressure-area isotherms. We also used an atomic force microscope to explore the microstructure of mixed DPPC/PA monolayers which was transferred to mica substrate by LB film technique. The five different mixed ratio of DPPC/PA is 1/9, 3/7, 5/5, 7/3, and 9/1. The results indicate that the collapse structure of DPPC is a convex granule-like structure accompanied with concave disk-like metastable structures, and the collapse structure of PA formed irregular convex structure. At surface pressure 45 mN/m, many cavities with depth of about 1 nm are observed for DPPC monolayer. We propose that these cavities will aggregate to form the disk-like metastable structures for increasing surface pressure. In mixed 9/1 DPPC/PA monolayer, the cavities appear at surface pressure 20 mN/m. However, the surface pressure of the cavities appear increases with increasing PA ratio.
50
Chen, Yan-shi, and 陳衍錫. "The effect of sterol on the POPE/DPPC membranes." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/3dytbq.
Full textAbstract:
碩士國立中央大學
生物物理研究所
101
The specialized membrane microdomain was found in the mammalian cells membrane which termed lipid rafts with different physical and chemical properties. The lipid rafts contain 3 to 5-fold the amount of cholesterol found in the surrounding bilayer. Like cholesterol in mammalian cell membrane, ergosterol is important to the raft in the yeast cell membrane. To gain a better understanding of the effect of sterols on biological membrane properties requires investigations of the phase behavior. We study the physical properties of model membranes for binary mixture containing DPPC and POPE, and ternary mixtures containing DPPC, POPE and ergosterol using fluorescence microscopy and deuterium nuclear magnetic resonance (2H-NMR). The morphology of model membranes was observed as a function of temperature and composition by fluorescence microscopy. DPPC or POPE was deuterium labeled alternatively such that the phase behavior of both DPPC and POPE can be observed by 2H-NMR. 70:30 POPE/DPPC are in coexistence of 2 types of so phases at 15 ℃. As the DPPC concentration increases to 50 mol%, the POPE-rich so phase disappears and lipid bilayer only showed DPPC-rich so phase. The results of ternary mixtures containing sterol are compared with those of binary mixture to investigate the effect of sterol. In the 70:30 DPPC/POPE and 50:50 DPPC/POPE, ergosterol induces the formation of a lo phase in the so-phase bilayers. Finally, we present a partial phase diagram to summarize our findings.