Literatura científica selecionada sobre o tema "Small amines"
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Artigos de revistas sobre o assunto "Small amines"
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Barham, Joshua P., e Jaspreet Kaur. "Site-Selective C(sp3)–H Functionalizations Mediated by Hydrogen Atom Transfer Reactions via α-Amino/α-Amido Radicals". Synthesis 54, n.º 06 (25 de outubro de 2021): 1461–77. http://dx.doi.org/10.1055/a-1677-6619.
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AbstractAmines and amides, as N-containing compounds, are ubiquitous in pharmaceutically-active scaffolds, natural products, agrochemicals, and peptides. Amides in nature bear a key responsibility for imparting three-dimensional structure, such as in proteins. Structural modifications to amines and amides, especially at their positions α to N, bring about profound changes in biological activity oftentimes leading to more desirable pharmacological profiles of small drug molecules. A number of recent developments in synthetic methodology for the functionalizations of amines and amides omit the need of their directing groups or pre-functionalizations, achieving direct activation of the otherwise relatively benign C(sp3)–H bonds α to N. Among these, hydrogen atom transfer (HAT) has proven a very powerful platform for the selective activation of amines and amides to their α-amino and α-amido radicals, which can then be employed to furnish C–C and C–X (X = heteroatom) bonds. The abilities to both form these radicals and control their reactivity in a site-selective manner is of utmost importance for such chemistries to witness applications in late-stage functionalization. Therefore, this review captures contemporary HAT strategies to realize chemo- and regioselective amine and amide α-C(sp3)–H functionalization, based on bond strengths, bond polarities, reversible HAT equilibria, traceless electrostatic-directing auxiliaries, and steric effects of in situ-generated HAT agents.1 Introduction2 Functionalizations of Amines3 Functionalizations of Carbamates4 Functionalizations of Amides5 Conclusion
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Johnson, Nnadikwe, Wopara Onuoha FIdelis, Onyewudiala Ibeawuchi Julius, Udechukwu Mathew Chidubem e Ewelike Asterius Dozie. "Development Design of Amine Sweetening Unit Plant of Natural Gas". International Journal for Research in Applied Science and Engineering Technology 10, n.º 9 (30 de setembro de 2022): 397–403. http://dx.doi.org/10.22214/ijraset.2022.46548.
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Abstract: In addition to reduced equipment sizes, lower circulation rates, and greater overall amine concentration, selective amines have become more popular for gas sweetening. Selective amines absorb H2S from CO2 through thermodynamic or kinetic processes. Selective amine mixtures may enable a small quantity of CO2 to remain in the treated gas. Plant capacity margins for selective amine units are frequently small. Increasing the acid gas concentration or throughput might result in sweet gas that does not fulfill CO2 specifications. Increasing the amine concentration, employing combinations of amines, and altering the lean amine temperature were explored since adding new equipment may be costly. Compared to increasing reboiler or pumping capacity, these factors need little or no extra capital.
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Li, Jin Tang, Shi Qiu, Rong Yi Chen, Chuan Hai Gan, Xue Zeng e Xue Tao Luo. "Hydrothermal Synthesis of Porous Materials Using Calcined Kaolin with Small Molecular Amine Templates". Advanced Materials Research 1025-1026 (setembro de 2014): 515–18. http://dx.doi.org/10.4028/www.scientific.net/amr.1025-1026.515.
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Three kinds of porous materials were synthesized using calcined kaolin with small molecular amine templates by hydrothermal methods. Sodium silicate was chose as silicon sources and three different amines namely acetamide, ethylenediamine and hexamethylenetetramine were chose as the organic templates. The physicochemical properties of obtained samples were characterized by X-ray diffraction, infrared spectrum and scanning electron microscopy.Crystallinity and morphology of samples were investigated. The influence of small molecular amines templates was discussed.
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Creaser, Colin S., John R. Griffiths e Brian M. Stockton. "Gas-Phase Ion Mobility Studies of Amines and Polyether/Amine Complexes Using Tandem Quadrupole Ion Trap/Ion Mobility Spectrometry". European Journal of Mass Spectrometry 6, n.º 2 (abril de 2000): 213–18. http://dx.doi.org/10.1255/ejms.339.
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The gas-phase positive ion mobility spectra of isomeric amines and polyether/amine complexes have been measured using a tandem quadrupole ion trap/ion mobility spectrometer. Ion mobilities of isomeric amines in helium, determined relative to benzene at pressures in the range 1–2 Torr, vary with the structure of the amine. The ability of quadrupole ion trap/ion mobility spectrometry to differentiate between a pharmacologically-active substance and an associated isomeric amine is demonstrated. Non-covalent complexes of cyclic and acyclic polyethers with protonated amines were generated by ion/molecule reactions in the ion trap and analysed by ion mobility spectrometry. The ion mobilities in helium may be interpreted in terms of the preferred conformations for these complexes. The use of polyether hosts as shift compounds for enhancing the relative mobilities of small amine guest ions is proposed.
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KIM, HYEONG SANG, e SUN JIN HUR. "Effect of In Vitro Human Digestion on Biogenic Amine (Tyramine) Formation in Various Fermented Sausages". Journal of Food Protection 81, n.º 3 (6 de fevereiro de 2018): 365–68. http://dx.doi.org/10.4315/0362-028x.jfp-17-372.
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ABSTRACT Biogenic amines are formed in various fermented foods by microbial amino acid decarboxylation activities, and ingestion of these amines may cause human illness. However, the effect of digestion on the biogenic amines in fermented sausages has not been studied. This study was conducted to determine the effect of in vitro human digestion with the enterobacteria Escherichia coli and Lactobacillus casei on concentrations of the biogenic amine tyramine in six types of fermented sausages. Tyramine concentration was not significantly changed until simulated digestion in the small intestine. However, tyramine concentration for all sausage samples was increased after simulated digestion in the large intestine. Addition of E. coli and L. casei dramatically increased the tyramine concentrations (P < 0.05). This result indicates that enterobacteria increase biogenic amine concentrations during human digestion.
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Liu, Wei, Yuxi Zhang, Shui Wang, Lisen Bai, Yanhui Deng e Jingzhong Tao. "Effect of Pore Size Distribution and Amination on Adsorption Capacities of Polymeric Adsorbents". Molecules 26, n.º 17 (30 de agosto de 2021): 5267. http://dx.doi.org/10.3390/molecules26175267.
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Polymeric adsorbents with different properties were synthesized via suspension polymerization. Equilibrium and kinetics experiments were then performed to verify the adsorption capacities of the resins for molecules of various sizes. The adsorption of small molecules reached equilibrium more quickly than the adsorption of large molecules. Furthermore, the resins with small pores are easy to lower their adsorption capacities for large molecules because of the pore blockage effect. After amination, the specific surface areas of the resins decreased. The average pore diameter decreased when the resin was modified with either primary or tertiary amines, but the pore diameter increased when the resin was modified with secondary amines. The phenol adsorption capacities of the amine-modified resins were reduced because of the decreased specific area. The amine-modified resins could more efficiently adsorb reactive brilliant blue 4 owing to the presence of polar functional groups.
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GARAI, G., M. T. DUEÑAS, A. IRASTORZA, P. J. MARTÍN-ÁLVAREZ e M. V. MORENO-ARRIBAS. "Biogenic Amines in Natural Ciders". Journal of Food Protection 69, n.º 12 (1 de dezembro de 2006): 3006–12. http://dx.doi.org/10.4315/0362-028x-69.12.3006.
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Biogenic amines play an important physiological role in mammals, and high amounts of some exogenous amines in human diet may contribute to a wide variety of toxic effects. These amines are commonly found in many foodstuffs, particularly in fermented products such as cheese, meat products, beer, wine, and ciders. Here, the level of biogenic amines in some natural ciders was examined. Twenty-four samples of cider purchased from commercial sources were analyzed by reverse-phase high-performance liquid chromatography and fluorescence detection after precolumn derivatization with o-phthaldialdehyde. Amine levels were variable, ranging from not detected to 23 mg/liter. The average level of total biogenic amines in ciders was 5.94 ± 8.42 mg/liter. Putrescine, histamine, and tyramine were the prevailing amines being present in 50.0, 37.5, and 33.3% of the ciders studied; very small amounts of ethylamine and phenylethylamine were observed in only one sample. Other cider parameters were analyzed to determine whether they affect the biogenic amine content in ciders, and the results were evaluated by applying cluster analysis and principal component analysis. Ciders that showed lower glycerol contents and higher amounts of 1,3-propanediol had much higher levels of histamine, tyramine, and putrescine, suggesting a high activity of lactic acid bacteria during cider making and thus the need for effective control of lactic acid bacteria.
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Ríos-García, Martiño, Berta Fernández, Jesús Rodríguez-Otero, Enrique M. Cabaleiro-Lago e Saulo A. Vázquez. "The PM6-FGC Method: Improved Corrections for Amines and Amides". Molecules 27, n.º 5 (3 de março de 2022): 1678. http://dx.doi.org/10.3390/molecules27051678.
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Recently, we reported a new approach to develop pairwise analytical corrections to improve the description of noncovalent interactions, by approximate methods of electronic structures, such as semiempirical quantum mechanical (SQM) methods. In particular, and as a proof of concept, we used the PM6 Hamiltonian and we named the method PM6-FGC, where the FGC acronym, corresponding to Functional Group Corrections, emphasizes the idea that the corrections work for specific functional groups rather than for individual atom pairs. The analytical corrections were derived from fits to B3LYP-D3/def2-TZVP (reference). PM6 interaction energy differences, evaluated for a reduced set of small bimolecular complexes, were chosen as representatives of saturated hydrocarbons, carboxylic, amine and, tentatively, amide functional groups. For the validation, the method was applied to several complexes of well-known databases, as well as to complexes of diglycine and dialanine, assuming the transferability of amine group corrections to amide groups. The PM6-FGC method showed great potential but revealed significant inaccuracies for the description of some interactions involving the –NH2 group in amines and amides, caused by the inadequate selection of the model compound used to represent these functional groups (an NH3 molecule). In this work, methylamine and acetamide are used as representatives of amine and amide groups, respectively. This new selection leads to significant improvements in the calculation of noncovalent interactions in the validation set.
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SCRUTTON, Nigel S., e Andrew R. C. RAINE. "Cation-π bonding and amino-aromatic interactions in the biomolecular recognition of substituted ammonium ligands". Biochemical Journal 319, n.º 1 (1 de outubro de 1996): 1–8. http://dx.doi.org/10.1042/bj3190001.
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Cation-π bonds and amino-aromatic interactions are known to be important contributors to protein architecture and stability, and their role in ligand-protein interactions has also been reported. Many biologically active amines contain substituted ammonium moieties, and cation-π bonding and amino-aromatic interactions often enable these molecules to associate with proteins. The role of organic cation-π bonding and amino-aromatic interactions in the recognition of small-molecule amines and peptides by proteins is an important topic for those involved in structure-based drug design, and although the number of structures determined for proteins displaying these interactions is small, general features are beginning to emerge. This review explores the role of cation-π bonding and amino-aromatic interactions in the biological molecular recognition of amine ligands. Perspectives on the design of ammonium-ligand-binding sites are also discussed.
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Katsura, Toshiya, Hiroshi Mizuuchi, Yukiya Hashimoto e Ken-Ichi Inui. "Transport of procainamide via H+/tertiary amine antiport system in rabbit intestinal brush-border membrane". American Journal of Physiology-Gastrointestinal and Liver Physiology 279, n.º 4 (1 de outubro de 2000): G799—G805. http://dx.doi.org/10.1152/ajpgi.2000.279.4.g799.
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Transport characteristics of procainamide in the brush-border membrane isolated from rabbit small intestine were studied by a rapid-filtration technique. Procainamide uptake by brush-border membrane vesicles was stimulated by an outward H+ gradient (pHin= 6.0, pHout = 7.5) against a concentration gradient (overshoot phenomenon), and this stimulation was reduced when the H+ gradient was subjected to rapid dissipation by the presence of a protonophore, FCCP. An outward H+gradient-dependent procainamide uptake was not caused by H+diffusion potential. The initial uptake of procainamide was inhibited by other tertiary amines with N-dimethyl or N-diethyl moieties in their structures, such as triethylamine, dimethylaminoethyl chloride, and diphenhydramine, but not by tetraethylammonium and thiamine. Furthermore, procainamide uptake was stimulated by preloading the vesicles with these tertiary amines ( trans-stimulation effect), indicating the existence of a specific transport system for tertiary amines. These findings indicate that procainamide transport in the intestinal brush-border membrane is mediated by the H+/tertiary amine antiport system that recognizes N-dimethyl or N-diethyl moieties in the structures of tertiary amines.
Teses / dissertações sobre o assunto "Small amines"
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Aleksenko, Ekaterina. "Small amines, associated proteins and stress responses in Arabidopsis". Electronic Thesis or Diss., université Paris-Saclay, 2024. http://www.theses.fr/2024UPASB076.
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En tant qu'organismes non mobiles, les plantes subissent une multitude de stress, comme des attaques de pathogènes et divers stress biotiques, des conditions de sol défavorables, des variations de température et de disponibilité en eau allant jusqu'à de forts stress hydriques. Elles ont développé des stratégies d'adaptation en utilisant des myriades de protéines et de métabolites, qui interagissent dans un réseau complexe de voies permettant aux plantes de réagir de manière appropriée à la nature et la sévérité des stress. Un de ces couples protéine-métabolite est l'acétyltransférase NATA1 et son produit, une petite diamine acétylée (acétyl-1,3-diaminopropane; acDAP). Ce couple est impliqué dans la réponse au stress hydrique, participant à la régulation des besoins antagonistes entre conservation de l'eau et absorption du gaz carbonique par les stomates en contrant la fermeture des stomates contrôlée par l'acide abscissique. Le premier axe de ma thèse s'est concentré sur l'étude de la protéine NATA1 et de la protéine NATA2, son proche homologue de fonction inconnue. NATA1 et NATA2 appartiennent à la superfamille des N-acétyltransférases de type Gcn5 (GNATs), qui compte des milliers de membres dans tous les domaines du vivant, agissant sur une large variété de substrats, depuis les protéines jusqu'à de petits métabolites, telles que des amines, et participant à diverses voies impliquées dans le développement, le métabolisme et les réponses aux stress. Présents en tandem dans le génome, les deux gènes NATA proviendraient d'une duplication. Malgré la conservation des domaines catalytiques et une identité de près de 80%, les deux protéines présentent des sélectivités de substrats différentes. Ainsi, la première question a été la suivante : « Comment NATA1 et NATA2 parviennent-elles à des sélectivités de substrats différentes malgré leur grande similarité ? », ce qui a conduit à une question plus large : « Comment la structure protéique des GNATs détermine-t-elle la sélectivité de substrats tels que de petites amines ? » Des approches de modélisation, de mutagenèse et des essais enzymatiques ont permis un aperçu de la façon dont NATA1 et NATA2 interagissent avec leurs substrats, et une identification des principales différences entre ces deux enzymes. Cependant, NATA1 n'a pas seulement divergé de NATA2 de par son activité enzymatique, mais aussi de par son profil d'expression. Les deuxième et troisième questions ont été les suivantes : « Comment les profils d'expression de NATA1 et NATA2 diffèrent-ils en réponse à des conditions de stress ? » et « Quels sont les rôles potentiels de NATA2 in planta ? » De nouveaux mutants des gènes NATA ont été générés par la stratégie CRISPR/Cas9 afin de faciliter l'exploration de ces questions. Enfin, une expérimentation en levure, basée sur une technique de double-hybride modifiée, a permis d'identifier une protéine qui interagit potentiellement avec l'acDAP (DBP), offrant la possibilité d'étudier de potentiels événements en aval médiés par l'acDAP. Le second axe de ma thèse a porté sur le rôle fonctionnel de ce nouvel acteur en exploitant les mutants DBP générés par la technique de CRISPR/Cas9As sessile organisms, plants face a multitude of unavoidable stresses, such as attacks from pathogens and various biotic stresses, unfavorable soil composition and drought and heat stress. They have developed adaptation strategies using myriads of proteins and metabolites, that interact in a complex network of pathways to allow the plant to respond appropriately according to the nature and severity of the stress. One such protein-metabolite pair, the NATA1 acetyltransferase and its product, a small acetylated diamine (acetyl-1,3-diaminopropane; acDAP), is involved in the drought stress response, aiding in balancing conflicting needs for water conservation and CO2 uptake by counteracting stomatal closure mediated by abscisic acid. My thesis had two axes, focusing firstly on NATA1 and its' close homolog of unknown function NATA2, and, secondly, on a potential downstream target of acetyl-DAP. NATA1 and NATA2 belong to the large Gcn5-Related N-Acetyltransferase (GNAT) superfamily, that has thousands of members in all domains of life acting on a variety of substrates from proteins to small amines and participating in various crucial developmental, metabolic and stress response pathways. Found in tandem in the genome, the two NATA genes are believed to have originated from a duplication event. However, despite the conservation of their catalytic domains and their nearly 80% identity overall, they have evolved different substrate selectivities. Thus, the first question addressed was “How do NATA1 and NATA2 achieve different substrate selectivities despite their high similarity?” leading to a broader question of “How does GNAT structure drive substrate selectivity for small amine substrates?” Modeling, mutagenesis and enzymatic assays provided insight into how NATA1 and NATA2 interact with their substrates and identified key differences between the enzymes. However, NATA1 has not only diverged from NATA2 in its' enzymatic activity, but also in its' expression pattern and, likely, its' roles in planta. The second and third questions were “How do NATA1 and NATA2 expression patterns differ in response to stress conditions?” and “What are the potential roles of NATA2?” Novel NATA mutants were generated using the CRISPR/Cas9 strategy to aid in exploring these questions. Finally, a modified yeast-two hybrid assay identified a potential acetyl-DAP binding protein (DBP), providing the opportunity to investigate potential downstream events mediated by acDAP. The second axis of my thesis questioned the functional role of this new actor as a potential target of acDAP by exploiting CRISPR-generated DBP mutants
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Perry, Mitchell Robert. "Catalytic synthesis of amines : from small molecules to nitrogen-containing polymers". Thesis, University of British Columbia, 2017. http://hdl.handle.net/2429/63137.
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Nguyen, Ha Vinh Lam [Verfasser]. "Small esters, ketones, and amines with large amplitude motions / Ha Vinh Lam Nguyen". Aachen : Hochschulbibliothek der Rheinisch-Westfälischen Technischen Hochschule Aachen, 2012. http://d-nb.info/1021515094/34.
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Janabi, Joseph. "Investigating Small Amine Molecules as Ice Recrystallization Inhibitors". Thesis, Université d'Ottawa / University of Ottawa, 2018. http://hdl.handle.net/10393/37779.
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Cryopreservation is a technique used to store cells and tissues for long time. It requires the addition of a cryoprotectant, which prevents damage to cells caused by the formation of large ice crystals. Few compounds have been classified as cryprotectants, and some of them are very toxic like DMSO. Our lab is interested in the synthesis of small, non-toxic cryoprotectants that possess ice recrystallization inhibition (IRI) activity. Much attention has been drawn towards small molecules that contain an amine group because they have some activity towards inhibiting ice recrystallization. Herein we have examined few monoamine and diamine molecules as well as PAMAM dendrimer for IRI activity. Some of the small molecules tested contain an aryl ring, and we found that changing the position of groups around the ring can have some impact in the IRI activity. We have also found that increasing the number of amines in a molecule can have little effect of the IRI activity. It is hoped that these findings can open new doors for further investigation in small amino molecules and the development of novel cryoprotectants.
Corticosteroids were first identified and isolated from both teleost and elasmobranch fish. Corticosterone and cortisol were measurable in the plasma of elasmobranchs and 1α-hydroxycorticosterone (1α-OH-B) was the dominant corticosteroid produced by the internal tissue. Limited amount of 1α-OH-B was synthesized because available supplies were exhausted in the early 1990s. Synthetic 1α-OH-B was used in steroid receptor studies to examine the evolution of the corticosteroid receptor system and measure stress levels.
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Woolley, John Christopher. "The synthesis and reactions of small ring amine oxides". Thesis, University of Liverpool, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.250549.
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Metters, Owen J. "Cooperative Lewis pairs in small molecule activation and dehydrocoupling of amine- and phosphine-boranes". Thesis, University of Bristol, 2016. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.702464.
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This thesis contains a diverse body of work based around the theme of Lewis acid/base chemistry. The reactivity of classical Lewis adducts, such as amine- and phosphine-boranes, has been investigated in addition to the more nascent field of frustrated Lewis pairs (FLPs). Chapter 1 contains a brief overview of the concept of Lewis acidity and basicity whilst also providing a survey of previous work relevant to this thesis. Chapter 2 reports a novel, modular synthetic route to intermolecular Zr/P FLPs with varying steric and electronic properties. The reactivity of these pairs with a plethora of small molecules has been assessed (H2, C02, Phenylacetylene, THF) and is found to be directly related to both the steric and electronic character of the Lewis acid and base employed. The results contained in Chapter 3 build. on those in Chapter 2. by applying the intermolecular Zr/P FLPs as catalysts for the dehydrocoupling of amineboranes. Initial insights into the mechanism of these dehydrocoupling reactions are also provided. Chapter 4 describes preliminary investigations into new directions for the field of transition metal FLP chemistry. Expansion of the intermolecular FLP paradigm to include alternate Lewis acids (Ti(IV) and Ti(III)) and Lewis bases (N-heterocyclic carbenes (NHCs)) has been attempted. Furthermore previously reported intramolecular ZrlP FLPs are shown to be active catalysts for the dehydrocoupling of primary and secondary phosphine-boranes. Finally Chapter 5 details an alternative approach to the synthesis of amine-borane dehydrocoupling products via the deprotonation of amineboronium cations and related species. This methodology has allowed for the synthesis of poly(N-methylaminoborane) in the absence of a transition metal catalyst, whilst also permitting the study of highly reactive primary aminoboranes (RNH=BH2, R = Me or Bu).
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Tonelli, Devin L. "Small Molecule Ice Recrystallization Inhibitors and Their Use in Methane Clathrate Inhibition". Thèse, Université d'Ottawa / University of Ottawa, 2013. http://hdl.handle.net/10393/23994.
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Inhibiting the formation of ice is an essential process commercially, industrially, and medically. Compounds that work to stop the formation of ice have historically possessed drawbacks such as toxicity or prohibitively high active concentrations. One class of molecules, ice recrystallization inhibitors, work to reduce the damage caused by the combination of small ice crystals into larger ones. Recent advances made by the Ben lab have identified small molecule carbohydrate analogues that are highly active in the field of ice recrystallization and have potential in the cryopreservation of living tissue.
A similar class of molecules, kinetic hydrate inhibitors, work to prevent the formation of another type of ice – gas hydrate. Gas hydrates are formed by the encapsulation of a molecule of a hydrocarbon inside a growing ice crystal. These compounds become problematic in high pressure and low temperature areas where methane is present - such as an oil pipeline.
A recent study has highlighted the effects of antifreeze glycoprotein, a biological ice recrystallization inhibitor, in the inhibition of methane clathrates. Connecting these two fields through the synthesis and testing of small molecule ice recrystallization inhibitors in the inhibition of methane hydrates is unprecedented and may lead to a novel class of compounds.
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Duddy, William John. "The geometry of hydrogen bonds and carbonyl-carbonyl interactions between trans-amides in proteins and small molecules". Thesis, University of Glasgow, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.414343.
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Musetti, Caterina. "SELECTIVE TARGETING OF NUCLEIC ACIDS BY SMALL MOLECULES: A DNA STRUCTURE RECOGNITION APPROACH". Doctoral thesis, Università degli studi di Padova, 2011. http://hdl.handle.net/11577/3422045.
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The discovery of new anticancer targets is the key factor for the development of more efficacious therapies. Sequence selective binding of double stranded DNA in the classical B form has been extensively employed to target small molecules to defined polynucleotide portions. More recently, ligand recognition of non canonical DNA foldings has been additionally considered a useful approach to selectively target distinct genomic regions. In this connection, G-quadruplexes represent an interesting system since they are believed to be physiologically significant arrangements. These non-canonical DNA structures are found at the ends of the human chromosomes (telomeres) as well as at promoter regions of several oncogenes where there is a cluster of guanine-rich sequences and they are likely to play important roles in the regulation of biological events. The induction and stabilization of the G-quadruplex arrangement by small molecules can lead to the inhibition of the telomerase activity by interfering with the interaction of the enzyme and its single stranded template. A similar molecular mechanism is likely involved in the transcriptional control that leads to the suppression of the oncogene transcription and, ultimately, in the regulation of the gene expression. As a result, the quadruplex topic is very attractive for the development of a specific anticancer strategy defined by a dramatic reduction of side effects, typical of chemotherapy.
The purpose of this work is to investigate the interactions between novel classes of small molecules and different quadruplex DNA sequences and conformations. These new molecules were properly designed providing systematic atom-wise substitutions based on rational evaluations of previous studied compounds in order to increase their selectivity for G-quadruplex structures and to reduce toxic effects. Biophysical and biological properties of all new derivatives are herein evaluated at molecular and cellular level.
The thesis work is divided into three main sections based on the structural features of the compounds object of study. The first part focuses on heterocyclic dications: upon changing their molecular binding shape, a correlation with G-quadruplex binding have been drawn. In particular it was possible to rationalize a shift in the binding modes, in particular between end stacking and groove recognition. Nevertheless a correlation between biophysical (G-quadruplex affinity) and biological (telomerase inhibition and cytotoxicity) results was not always clear. This feature may suggest the involvement of cellular targets different from the telomere and that are now under investigation.
In Chapter 3, the DNA binding properties of some phenantroline derivatives in presence and in absence of Ni(II) and Cu(II) are investigated. We confirmed that different complex geometries involving one, two or three ligands per metal ion can affect the pattern of DNA recognition by driving nucleic acid conformational changes.
Finally, in Chapter 4 some transplatin derivatives are evaluated. We focused our attention on defining the compounds capability to form adducts, with the nucleic acids, the nature of adducts and the kinetics of adduct formation not only on double strand DNA but also using single strand as well as G-quadruplex as targets. The results showed how different structural modifications can cooperate to greatly affect the potential interaction of the compounds. Interestingly it turned out their preference to react on single stranded DNA portions than to double stranded ones. This is probably due to an unfavourable orientation of the reactive groups when the molecule interacts with the DNA substrate. As a result, they appear to crosslink unpaired strands. By extending these results at cellular level they can reflect distinct distribution of platination site along the genome in comparison to cisplatin and even transplatin.
The results obtained increment the available knowledge of DNA-small molecules interaction. In particular it emerged that a conserved interaction mode is consistent with biological effects. On the other hand, a shift in the binding mode can drive to different cytotoxic effects. This can provide a rationale for subsequent drug structure optimization leading to the development of new efficient and selective anticancer agents.La scoperta di nuovi target anticancro è il fattore chiave per lo sviluppo di terapie sempre più efficaci. Lo studio del legame selettivo a sequenze di DNA a doppia elica nella classica forma B è stato largamente impiegato al fine di direzionare piccole molecole verso porzioni polinucleotidiche definite. Più recentemente, il riconoscimento (da parte di ligandi) di porzioni non canoniche di DNA si può tradurre in un metodo vantaggioso per indirizzare questi composti verso regioni distinte del genoma. A tale proposito, le strutture G-quadruplex rappresentano un sistema interessante poiché sono ritenute fisiologicamente significative. Queste strutture “non-canoniche” di DNA si trovano alle estremità del cromosoma (telomeri) così come in varie regioni promotrici di oncogeni in cui vi è un’abbondante presenza di residui guaninici e sembrano coinvolte nella regolazione di importanti eventi biologici. Pare infatti che l'induzione e la stabilizzazione di strutture G-quadruplex dalle parte di piccole molecole porti all'inibizione dell'attività della telomerasi interferendo con l'interazione tra l’enzima e il suo substrato a singola catena. Un simile meccanismo molecolare è probabilmente coinvolto anche nel controllo della regolazione dell'espressione genica e può portare alla soppressione della trascrizione di un oncogene. Di conseguenza, “l’approccio G-quadruplex” si rivela molto interessante per lo sviluppo di una strategia anticancro specifica caratterizzata anche da una riduzione drammatica degli effetti collaterali, tipici della chemioterapia. Lo scopo di questo lavoro è lo studio delle interazioni tra nuove famiglie di piccole molecole e diverse conformazioni di DNA G-quadruplex. Queste nuove molecole sono state opportunamente progettate apportando sostituzioni di atomi o gruppi funzionali basate sulla valutazione di composti precedentemente studiati al fine di aumentare la loro selettività per strutture G-quadruplex e di ridurre gli effetti tossici. Le proprietà biofisiche e biologiche di tutti i nuovi derivati sono state valutate al livello molecolare e cellulare. Il lavoro di tesi si divide in tre parti in base alle caratteristiche strutturali dei composti. La prima parte è dedicata alla studio di dicationi eterociclici: si è cercato correlare modifiche nella conformazione molecolare con l’affinita’ verso strutture G-quadruplex. In particolare è stato possibile razionalizzare cambiamenti della modalità di legame in base alla struttura dei composti esaminati. Tuttavia una correlazione fra i risultati biofisici (affinità G-quadruplex) e biologici (inibizione della telomerasi e citotossicità) non è risultata sempre definita. Ciò può suggerire il coinvolgimento di bersagli cellulari diversi dal telomero umano. Nel capitolo 3, sono state studiate le proprietà di legame al DNA di alcuni derivati fenantrolinici in presenza ed in assenza di Ni (II) e Cu (II). Abbiamo confermato che complessi caratterizzati da diverse geometrie che coinvolgono una, due o tre molecole per ione possono compromettere o meno il riconoscimento del DNA o determinare cambiamenti conformazionali dell'acido nucleico. Per concludere, il capitolo 4 è dedicato allo studio di derivati del transplatino. In particolare ci siamo focalizzati nel definire la capacità dei composti di formare addotti, la natura dei complessi e la cinetica di formazione del complesso non solo con DNA a doppio filamento ma utilizzando anche substrati a singola catena come il G-quadruplex. I risultati hanno dimostrato come diverse modifiche strutturali possano avere un ruolo importante nell’interazione dei composti con gli acidi nucleici. E’ risultata interessante la loro preferenzialità a reagire con porzioni di DNA a singolo filamento rispetto a sequenze a doppia elica. Ciò è probabilmente dovuto ad uno sfavorevole orientamento dei gruppi reattivi quando la molecola interagisce con il substrato di DNA. Di conseguenza, i composti sembrano formare un cross-link tra due filamenti non appaiati. A livello cellulare, questi risultati riflettono una distinta distribuzione del sito di platinazione all’interno del genoma rispetto al cisplatino e perfino rispetto al transplatino. I risultati ottenuti incrementano la conoscenza disponibile sull’interazione tra DNA e piccole molecole. In particolare è emerso che la conservazione della modalità di interazione si correla con effetti biologici definiti. Al contrario, una variazione della modalità di legame può portare a effetti citotossici differenti. Ciò può fornire una spiegazione razionale per una successiva ottimizzazione della struttura dei composti finalizzata allo sviluppo di nuovi agenti antitumorali efficaci e selettivi.
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McMullon, Max William. "Exploiting anionically-tethered N-heterocyclic carbene complexes for small molecule activation". Thesis, University of Edinburgh, 2018. http://hdl.handle.net/1842/31079.
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N-heterocyclic carbenes (NHCs) can be used as ligands for organometallics complexes, which can then facilitate numerous catalytic applications, such as, C-H activation, small molecule activation and numerous materials applications. The use of anionically-tethered NHCs for usage with electropositive metals has been pioneered by the Arnold group within the last decade. This thesis describes the synthesis of both aryloxide- and amide-tethered NHC organometallic complexes of s-, p-, d- and f-block metals to provide a platform for small molecule activation. Once synthesised, the reactivity of some of these complexes were tested by reaction with CO2 with the aim of turning a molecule considered a harmful (environmentally), waste product into value added products, potentially providing an alternative fuel source. Chapter One introduces the use of anionically-tethered NHCs for use in a number of organometallic complexes as well as their current potential as catalysts for a number of important small molecules. This chapter focuses upon the differences between complexes tethered with anionic O, N, P, S elements, f-element NHC complexes and the use of d-block NHC complexes for catalysis. Chapter Two contains the synthesis and characterisation of a number of aryloxy-tethered NHC p-, d- and f-block organometallic complexes using the ligand H2(LArO R)2. The synthesis of SnII complexes including the synthesis of new ‘normal’ ‘abnormal’ complexes given enough steric bulk around the Sn centre due to the lone pair present in Sn complexes, preventing one of the ligands binding through the classical carbene position and therefore binding through the backbone C4 carbon. The synthesis of MII (Zn, Co and Fe) complexes to compare the solid-state structure and binding mode of the carbenes. The synthesis and characterisation of MIII (Ce and Eu) complexes to assess the solid-state structure and binding modes within f-bock complexes. Chapter Three investigates the reactivity of the MII complexes (Sn, Zn, and Fe) with CO2. Successful reactions were characterised using NMR and further treated with alkynes to target catalytic reactions. Chapter Four contains reactions to target a number of amide-tethered bis (NHC) s-, p-, d- and f-block organometallic complexes using the proligand, H4(LN Mes)Cl3. Deprotonation studies undertaken with a number of bases to give the MI (Li and K) salts and MII (Mg) salts and proved to be unsuccessful upon isolation. Reactions to synthesise the p-, d- and f-block complexes were then undertaken using in situ free carbene production as well as the attempted isolation of the free carbene, both of which also proved unsuccessful. Chapter Five provides an overall conclusion to the work presented in Chapters Two, Three and Four within this thesis. Chapter Six gives the experimental and characterising data for the complexes and reactions.
Livros sobre o assunto "Small amines"
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Plensa, Jaume. Jaume Plensa: Ópera, teatro y amigos = Opera, theater & friends. Madrid: Fundación de Crédito Oficial, 2005.
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Zhang, Kui. Ab initio studies of amino acids and small peptides. 1996.
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Servais, Aude, e Bertrand Knebelmann. Cystinuria. Oxford University Press, 2016. http://dx.doi.org/10.1093/med/9780199972135.003.0024.
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Cystinuria (OMIM #220100) is an autosomal recessive disorder of a dibasic amino acid transport in the apical membrane of epithelial cells of the renal proximal tubule and small intestine. It leads to increased urinary cystine excretion and recurrent urolithiasis. The cystine transporter is an heterodimeric transporter which is composed of a heavy subunit, rBAT, linked to a light subunit, b0,+AT. Two genes, SLC3A1 (solute carrier family 3 member 1) and SLC7A9, coding for rBAT and b0,+AT, account for the genetic basis of cystinuria. Cystinuria may lead to obstruction, infections, and ultimately to renal insufficiency. The diagnosis of cystinuria mainly relies on stone analysis, urinary cystine measurement, or urinary cystine crystal identification. Medical treatment is based upon a stepwise strategy using hydration and alkalinization as basic measures, with the addition of thiol derivatives in refractory cases. Urological interventions are often indicated for the management of cystine stones >5 mm in diameter.
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Nozière, Pierre. INRA feeding system for ruminants. Editado por Daniel Sauvant e Luc Delaby. Wageningen Academic Publishers, 2018. http://dx.doi.org/10.3920/978-90-8686-872-8.
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The INRA Feeding System for Ruminants has been renewed to better address emerging challenges for animal nutrition: prevision of productive responses, product quality, animal health and emissions to the environment, in a larger extent of breeding contexts. The new system is mainly built from meta-analyses of large data bases, and modelling. The dietary supply model accounts for digestive interactions and flows of individual nutrients, so that feed values depend on the final ration. Animal requirements account for variability in metabolic efficiency. Various productive and non-productive animal responses to diets are quantified. This book presents the whole system for dairy and meat, large and small ruminant production, including specificities for tropical and Mediterranean areas. The first two sections present biological concepts and equations (with their field of application and statistical accuracy) used to predict intake (including at grazing) and nutrient supply (Section 1), animal’s requirements and multiple responses to diets (Section 2). They apply to net energy, metabolisable protein and amino acids, water, minerals and vitamins. Section 3 presents the use of concepts and equations in rationing with two purposes: (1) diet calculation for a given performance objective; and (2) prediction of the multiple responses of animal to diet changes. Section 4 displays the tables of feed values, and their prevision. All the equations and concepts are embedded in the fifth version of INRAtion® software for practical use.
Capítulos de livros sobre o assunto "Small amines"
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Sapse, Anne-Marie. "Some Small Peptides". In Molecular Orbital Calculations for Amino Acids and Peptides, 124–37. Boston, MA: Birkhäuser Boston, 2000. http://dx.doi.org/10.1007/978-1-4612-1354-3_11.
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Eggeling, Lothar. "Exporters for Production of Amino Acids and Other Small Molecules". In Amino Acid Fermentation, 199–225. Tokyo: Springer Japan, 2016. http://dx.doi.org/10.1007/10_2016_32.
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Kwak, S., H. Aizawa, M. Ishida, Y. Gotoh e H. Shinozaki. "Small neurons in the lower spinal cord are selectively damaged in the spastic rat by acromelic acid". In Amino Acids, 318–26. Dordrecht: Springer Netherlands, 1990. http://dx.doi.org/10.1007/978-94-011-2262-7_36.
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Sapse, Anne-Marie. "Theoretical Calculations on Small Amino Acids". In Molecular Orbital Calculations for Amino Acids and Peptides, 15–26. Boston, MA: Birkhäuser Boston, 2000. http://dx.doi.org/10.1007/978-1-4612-1354-3_2.
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Ameh, D. A., e J. R. Thompson. "Effect of Escherichia coli endotoxin on some aspects of amino acid and protein metabolism by the rat small intestine". In Amino Acids, 1009–16. Dordrecht: Springer Netherlands, 1990. http://dx.doi.org/10.1007/978-94-011-2262-7_126.
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Krusemark, Casey J., Brian L. Frey, Lloyd M. Smith e Peter J. Belshaw. "Complete Chemical Modification of Amine and Acid Functional Groups of Peptides and Small Proteins". In Methods in Molecular Biology, 77–91. Totowa, NJ: Humana Press, 2011. http://dx.doi.org/10.1007/978-1-61779-148-2_6.
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Wang, Shengping, Gang Liu, Lichuang Cai, Jiannan Ding e Yulong Yin. "Development of Micro-ecological System in Small and Large Intestine of Piglets". In Nutritional and Physiological Functions of Amino Acids in Pigs, 75–87. Vienna: Springer Vienna, 2013. http://dx.doi.org/10.1007/978-3-7091-1328-8_6.
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Blachier, François, Guoyao Wu, Yulong Yin, Yongqing Hou e Mireille Andriamihaja. "Developmental Amino Acid Metabolism in the Pig Small and Large Intestine Epithelial Cells". In Nutritional and Physiological Functions of Amino Acids in Pigs, 59–74. Vienna: Springer Vienna, 2013. http://dx.doi.org/10.1007/978-3-7091-1328-8_5.
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Segal, M. B., e B. V. Zlokovic. "The interaction of small peptides with the various cellular interfaces of the blood-brain barrier". In The Blood-Brain Barrier, Amino Acids and Peptides, 123–47. Dordrecht: Springer Netherlands, 1990. http://dx.doi.org/10.1007/978-94-009-2229-7_6.
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Wu, Miaomiao, Zexi Zhang, Jiaxi Yong, Peer M. Schenk, Dihua Tian, Zhi Ping Xu e Run Zhang. "Determination and Imaging of Small Biomolecules and Ions Using Ruthenium(II) Complex-Based Chemosensors". In Metal Ligand Chromophores for Bioassays, 199–243. Cham: Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-031-19863-2_6.
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AbstractLuminescence chemosensors are one of the most useful tools for the determination and imaging of small biomolecules and ions in situ in real time. Based on the unique photo-physical/-chemical properties of ruthenium(II) (Ru(II)) complexes, the development of Ru(II) complex-based chemosensors has attracted increasing attention in recent years, and thus many Ru(II) complexes have been designed and synthesized for the detection of ions and small biomolecules in biological and environmental samples. In this work, we summarize the research advances in the development of Ru(II) complex-based chemosensors for the determination of ions and small biomolecules, including anions, metal ions, reactive biomolecules and amino acids, with a particular focus on binding/reaction-based chemosensors for the investigation of intracellular analytes’ evolution through luminescence analysis and imaging. The advances, challenges and future research directions in the development of Ru(II) complex-based chemosensors are also discussed.
Trabalhos de conferências sobre o assunto "Small amines"
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Takebe, K., Y. Elakneswaran, Y. Yoda e R. Kitagaki. "Enhancing Co2 mineralisation in steel slag with amines for developing a waste to construction material". In International Symposium on Earth Resources Management & Environment - ISERME 2024, 249–51. Division of Sustainable Resources Engineering, Hokkaido University, Japan, 2024. https://doi.org/10.31705/iserme.2024.48.
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Global warming has become an urgent issue due to the increasing atmospheric emission of CO2. In Japan, the steel industry emits a large amount of CO₂ and produces steel slag as an alkaline waste product. Using this steel slag to absorb CO₂ in flue gas is an effective approach for CO₂ emissions and recycling. This study introduces a novel technology utilizing amines to facilitate CO₂ sequestration in blast furnace slag. This innovative approach demonstrates significant potential and flexibility compared to conventional CO₂ capture technologies. In this study, changes in the carbonation efficiency of slag with three types of amines (N-Methyldiethanolamine (MDEA), 2-(Methylamino)ethanol (MAE), 2-Amino-2-methyl-1-propanol (AMP)) were investigated. In addition, this study examined the effect of Portland cement on the carbonation efficiency. In wet carbonation, the CO₂ fixation process entails the introduction of 1 mol/L of amine, water, slag, and cement, followed by a 24-hour leaching process and subsequent 24-hour carbonation. The results showed that adding AMP and cement exhibited the most significant increase in carbonation efficiency, resulting in the formation of 11.07% of the solid weight as CaCO₃, as confirmed by thermogravimetric analysis (TGA). Changes in calcium ion concentration and pH were also investigated in this study. The results showed that a small amount of Ca²⁺ dissolution and an increase in pH occurred in the early stages of the reaction and that the majority of Ca²⁺ dissolution occurred simultaneously with carbonation. In dry carbonation, slag cement paste, made by mixing amine, slag, and cement, was carbonated for 28 days after a 28-day curing period to determine changes in its properties. W/S ratio is 10, slag/cement ratio is 19, amine concentration is 1 mol/L, and CO₂ concentration is 0%, 0.04%, 5%, and 15％. Strength tests showed an increase in strength in the slag cement paste with the addition of MDEA.
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Huertas Cardozo, Jose Ignacio, e Sebastia´n Izquierdo Cifuentes. "H2S and CO2 Filtration of Biogas Used in Internal Combustion Engines for Power Generation". In ASME 2009 International Mechanical Engineering Congress and Exposition. ASMEDC, 2009. http://dx.doi.org/10.1115/imece2009-12068.
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Currently, there is an increasing interest in connecting thousands of small electrical plants powered by renewable energy sources to national electrical grids. The use of biogas as fuel for internal combustion engines connected to an electric generator is emerging as one of the most attractive alternatives because of its very low cost benefit ratio and very high positive impact on the environment. However, the use of biogas to generate electricity has been limited by its high content of H2S (1800–3500 ppm) and CO2 (∼40%). CO2 presence reduces the energetic density of the fuel and therefore the power output of the system. The high content of H2S corrodes important components of the engine like the combustion chamber, bronze gears and the exhaust system. This work aims to design and manufacture a low-cost industrial filter for this application. Among the different available methodologies, CaO, NaOH and amines where selected as the most appropriate for a typical farm application of 100 kW electric generations. Since there is not reported data for the H2S absorbing capacity of these substances, it was proposed to measure it by means of a bubbler. It is an experimental set up where the gas stream passes through a fixed amount of the absorbing substance until it becomes saturated. The absorbing capacity is determined as the amount of substance being trapped divided by the mass of the absorbing substance being used. Results showed an absorbing capacity of 2.8, 41.4 and 124.8 g of H2S per Kg of NaOH, CaO and monoethanolamine respectively. A gas absorbing system of amines was designed and manufactured for H2S and CO2 biogas filtration. Three different types of amines were evaluated: Monoethanolamine, Diethanolamine, and methyldiethanolamine. Results show that all the amines require a ratio of amines to biogas flow of 0.7 to obtain a 95% of H2S filtering efficiency. This data represent only a 30% of H2S mass transfer efficiency of the filter when it is compared against the mass transfer expected under quasi equilibrium conditions. Work is under way to design a high efficiency amine column for biogas treatment.
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Sun, Hejian, John C. Donini, Kirk H. Michaelian, Sankara Papavinasam e R. Winston Revie. "Application of the Quartz Crystal Microbalance to Corrosion Investigation". In 1998 2nd International Pipeline Conference. American Society of Mechanical Engineers, 1998. http://dx.doi.org/10.1115/ipc1998-2026.
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The quartz crystal microbalance (QCM) provides an extremely sensitive technique for detecting small changes in mass and viscosity on the quartz crystal surface. QCM can be used in oil, gas or water without the problems of high solution resistance. In order to use QCM to model pipeline corrosion, an iron quartz crystal electrode was prepared using an electrodeposition method. The reproducibility, effectiveness and accuracy of the iron QCM were tested in salt solution. The adsorption of amines was studied to investigate their effects on the corrosion behaviour of the iron QCM.
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Qurbanova R.Sh., Asadova Sh.Sh., Vahabova Sh.B., Qurbanova R. Sh ,. Asadova Sh Sh ,. Vahabova Sh B. "CLİNİCAL AND MORPHOLOGİCAL PATTERNS OF ENDOCCRİNE-CELL CARSİNOMA OF UTERİ". In THE FIRST INTERNATIONAL SCIENTIFIC – PRACTICAL VIRTUAL CONFERENCE IN MODERN & SOCIAL SCIENCES: NEW DIMENSIONS, APPROACHES AND CHALLENGES. IRETC, 2022. http://dx.doi.org/10.36962/mssndac-01-11.
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The relevance of the problem. The endicrine-cell carsinoma of corpus uteri and of the cervex uteri remains insufficiently studied, from clinical and proqnosis point of view insignificant group of malignant epithelial organ tumors. The purpose of the study. Taking into consideration all stated above, as the goal of current investigation has been appeared complex statistic, clinic, laboratory-instrumental and morphological study of this cancer with comparative analysis of results in different types of treatment, and also including progression and prognosis of the process. Material and methods. 405 cases of endocrine cell carcinoma of corpus uteri were identified within 2016- 2021. Complaints, anamnesis and clinical stages of the process approximately didn’t differ from the analogous groups of comparison of patient by the moment of appeal for the specialized aid. The obtained results and their discussion. It was determined that the fraquancy of countering of the endocrine cell carcinoma of corpus uteri is 26,1%, but the cancer of cervix uteri 12,7% from total number patients, respectively. It was proved that there exists the direct correlation between the frequency of endocrine cell carcinoma of corpus uteri and anatomical section of organ. In 56,0% od cases primary tumor origin is situated in lower segment of corpus, circus cervix or proximal part of cervical canal. “Carcinoids” and “Small cell homomorphous solid squamous cell and glandular carcinoids” were encountered most frequently among histotypes and the versions. Morphologically in tumor tissue were revealed mono and double specialized apudocytes, producing olygopeptides and amines with paraendocrine effects. Proceeding from secretory status of the endocrine tumor component were distinguished following clinical-morphological subgroups of endocrine cell carcinoma of corpus utseri: 1) with prevailing secretion of peptides (excluding the somatostatin); 2) with prevailing secretion of amines and somatostatin; 3) with similar secretion of peptides and amines. It was proved that, there is direct close correlation between prevailing hormonal status and clinical progression of endocrine-cell carcinoma of corpus uteri. Despite of somatostatin predominant secretion of oligopeptides by the tumor accelerates clinical progression, and brings to early and multidirectional metastases. On the contrary, with prevailing secretion of amines (serotonin, melatonin) and somatostatin the process doesn’t improving, and metastases, also, recurrences after radical therapy isn’t seen. It was revealed, that when choosing the tactic of radical treatment, side by side with the other factors, must be taken into consideration the hormonal status of endocrine-cell carcinoma of corpus uteri. High prevalence of secretion of oligopeptides in endocrine-cell carcinoma of corpus uteri can be useful in direct indication for choosing of complex or combinative treatment with necessary use radical surgical operation. Keywords: distinguished following clinical-morphological subgroups.
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Mo¨ller, Bjo¨rn Fredriksson, Mohsen Assadi e Ulf Linder. "CO2-Free Power Generation: A Study of Three Conceptually Different Plant Layouts". In ASME Turbo Expo 2003, collocated with the 2003 International Joint Power Generation Conference. ASMEDC, 2003. http://dx.doi.org/10.1115/gt2003-38413.
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Ever since the release of the Kyoto protocol the demand for CO2-free processes have been increasing. In this paper three different concepts with no or a very small release of CO2 to the atmosphere are evaluated and compared concerning plant efficiency and investment cost. A novel approach to biomass gasification is proposed to provide fuel for a combined gas turbine cycle, where the biomass is considered to be a renewable fuel with zero impact regarding CO2 in the exhaust gases. The gasification concept used is a Dual Pressurised Fluidised Bed Gasifier (DPFBG) system, using steam and recycled product gas as fluidising agent in the gasification reactor. In the separate combustion reactor air is used as fluidising agent. The second cycle is a hybrid fuelled Humid Air Turbine (HAT) cycle with post-combustion CO2-separation. Steam used for regenerating the amines in the separation plant is produced using a biomass boiler, and natural gas is used as fuel for the humid air turbine. With this fuel mix the net release of CO2 can even be less than zero if the exhaust gas from the steam generator is mixed and cleaned together with the main exhaust gas flow. The third cycle proposed is a combined cycle with postcombustion CO2-separation and the steam generation for the CO2-separation integrated in the bottoming steam cycle. All power cycles have been modelled in IPSEpro™, a heat and mass balance software, using advanced component models developed by the authors. An equilibrium model is employed both for the gasification and the separation of CO2 from exhaust gases. All three power cycles show efficiencies around 45%, which is high for a biomass gasification cycle. The HAT and the combined cycle show efficiency drops of about 8 percentage points, due to the post-combustion treatment of exhaust gases.
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Lamango, Nazarius S., Byron J. Aguilar, Augustine T. Nkembo, Randolph Duverna, Felix Amissah, Rosemary A. Poku e Seth Y. Ablordeppey. "Abstract LB-14: Polyisoprenylated cysteinyl amides as targeted small molecule anti-Ras therapies". In Proceedings: AACR Annual Meeting 2014; April 5-9, 2014; San Diego, CA. American Association for Cancer Research, 2014. http://dx.doi.org/10.1158/1538-7445.am2014-lb-14.
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Jha, Rashmi, M. N. Hoda e A. K. Saini. "Implementing Best Practices in ERP for Small & Medium Enterprises". In 2008 IEEE Symposium on Advanced Management of Information for Globalized Enterprises, AMIGE. IEEE, 2008. http://dx.doi.org/10.1109/amige.2008.ecp.51.
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Liu, Gang, Yan-Hu Li, Wan-Yi Tan, Qing-Duan Li, Xu-Hui Zhu, Junbiao Peng e Yong Cao. "Small-molecule amine compound as electron-injection layer for organic light-emitting diodes". In SPIE Organic Photonics + Electronics, editado por Rachel Jakubiak, Manfred Eich e Jean-Michel Nunzi. SPIE, 2012. http://dx.doi.org/10.1117/12.929669.
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Gaci, Omar, e Stefan Balev. "The Small-World Model for Amino Acid Interaction Networks". In 2009 International Conference on Advanced Information Networking and Applications Workshops (WAINA). IEEE, 2009. http://dx.doi.org/10.1109/waina.2009.41.
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Kaegi, Zoe E., Suzanne M. Underhill e Susan Amara. "Methamphetamine Activates Small GTPase Rac1 Independently from RhoA and Trace Amine-Associated Receptor 1 (TAAR1)". In ASPET 2024 Annual Meeting Abstract. American Society for Pharmacology and Experimental Therapeutics, 2024. http://dx.doi.org/10.1124/jpet.153.129663.
Texto completo da fonteRelatórios de organizações sobre o assunto "Small amines"
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Hefetz, Abraham, e Justin O. Schmidt. Use of Bee-Borne Attractants for Pollination of Nonrewarding Flowers: Model System of Male-Sterile Tomato Flowers. United States Department of Agriculture, outubro de 2003. http://dx.doi.org/10.32747/2003.7586462.bard.
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The use of bee natural product for enhancing pollination is especially valuable in problematic crops that are generally avoided by bees. In the present research we attempted to enhance bee visitation to Male Sterile (M-S) tomato flowers generally used in the production of hybrid seeds. These flowers that lack both pollen and nectar are unattractive to bees that learn rapidly to avoid them. The specific objects were to elucidate the chemical composition of the exocrine products of two bumble bee species the North American Bombus impatiens and the Israeli B. terrestris. Of these, to isolate and identify a bee attractant which when sprayed on M-S tomato flowers will enhance bee visitation, and to provide a procedure of the pheromone application regime. During the research we realized that our knowledge of B. impatiens is too little and we narrowed the objective to learning the basic social behavior of the bees and the pattern of foraging in a flight chamber and how it is affected by biogenic amines. Colonies of B. impatiens are characterized by a high number of workers and a relatively small number of queens. Size differences between queens and workers are pronounced and the queen seems to have full control over egg laying. Only about 9% of the workers in mature colonies had mature oocytes, and there were no signs of a "competition phase" as we know in B. terrestris. Queens and workers differ in their exocrine bouquet. Queen's Dufour's gland possesses a series of linear, saturated and unsaturated hydrocarbons whereas that of workers contains in addition a series of wax-type esters. Bees were trained to either visit or avoid artificially scented electronic flowers in a flight chamber. Since bee also learned to avoid scented non-rewarding flowers we attempted to interfere with this learning. We tested the effect of octopamine, a biogenic amine affecting bee behavior, on the choice behavior of free-flying bumblebees. Our results show that octopamine had no significant effect on the bees' equilibrium choice or on the overall rate of the behavioral change in response to the change in reward. Rather, octopamine significantly affected the time interval between the change in reward status and the initiation of behavioral change in the bee. In B. terrestris we studied the foraging pattern of the bees on tomato flowers in a semi commercial greenhouse in Yad Mordechai. Bee learned very quickly to avoid the non- rewarding M-S flowers, irrespective of their arrangement in the plot, i.e., their mixing with normal, pollen bearing flowers. However, bees seem to "forget" this information during the night since the foraging pattern repeats itself the next morning. Several exocrine products were tested as visitation enhancers. Among these, tarsal gland extracts are the most attractive. The compounds identified in the tarsal gland extract are mostly linear saturated hydrocarbons with small amounts of unsaturated ones. Application was performed every second day on leaves in selected inflorescences. Bee visitation increased significantly in the treated inflorescences as compared to the control, solvent treated. Treatment of the anthers cone was more effective than on the flower petals or the surrounding leaves. Methanol proved to be a non-flower-destructive solvent. We have shown that bumble bees (B. terrestris) can be manipulated by bee-borne attractants to visit non-rewarding flowers. We have further demonstrated that the bees learning ability can be manipulated by applying exogenously octopamine. Both methods can be additively applied in enhancing pollination of desired crops. Such manipulation will be especially useful in tomato cultivation for hybrid seed production.
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Plymate, Stephen R. Inhibition of the Androgen Receptor Amino-Terminal Domain by a Small Molecule as Treatment for Castrate-Resistant Prostate Cancer. Fort Belvoir, VA: Defense Technical Information Center, outubro de 2014. http://dx.doi.org/10.21236/ada609928.
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Plymate, Stephen R. Inhibition of the Androgen Receptor Amino-Terminal Domain by a Small Molecule as Treatment for Castrate-Resistant Prostate Cancer. Fort Belvoir, VA: Defense Technical Information Center, outubro de 2012. http://dx.doi.org/10.21236/ada566784.
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Plymate, Stephen R. Inhibition of the Androgen Receptor Amino-Terminal Domain by a Small Molecule as Treatment for Castrate-Resistant Prostate Cancer. Fort Belvoir, VA: Defense Technical Information Center, outubro de 2013. http://dx.doi.org/10.21236/ada590496.
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Whitham, Steven A., Amit Gal-On e Tzahi Arazi. Functional analysis of virus and host components that mediate potyvirus-induced diseases. United States Department of Agriculture, março de 2008. http://dx.doi.org/10.32747/2008.7591732.bard.
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The mechanisms underlying the development of symptoms in response to virus infection remain to be discovered in plants. Insight into symptoms induced by potyviruses comes from evidence implicating the potyviral HC-Pro protein in symptom development. In particular, recent studies link the development of symptoms in infected plants to HC-Pro's ability to interfere with small RNA metabolism and function in plant hosts. Moreover, mutation of the highly conserved FRNK amino acid motif to FINK in the HC-Pro of Zucchini yellow mosaic virus (ZYMV) converts a severe strain into an asymptomatic strain, but does not affect virus accumulation in cucurbit hosts. The ability of this FINK mutation to uncouple symptoms from virus accumulation creates a unique opportunity to study symptom etiology, which is usually confounded by simultaneous attenuation of both symptoms and virus accumulation. Our goal was to determine how mutations in the conserved FRNK motif affect host responses to potyvirus infection in cucurbits and Arabidopsis thaliana. Our first objective was to define those amino acids in the FRNK motif that are required for symptoms by mutating the FRNK motif in ZYMV and Turnip mosaic virus (TuMV). Symptom expression and accumulation of resulting mutant viruses in cucurbits and Arabidopsis was determined. Our second objective was to identify plant genes associated with virus disease symptoms by profiling gene expression in cucurbits and Arabidopsis in response to mutant and wild type ZYMV and TuMV, respectively. Genes from the two host species that are differentially expressed led us to focus on a subset of genes that are expected to be involved in symptom expression. Our third objective was to determine the functions of small RNA species in response to mutant and wild type HC-Pro protein expression by monitoring the accumulation of small RNAs and their targets in Arabidopsis and cucurbit plants infected with wild type and mutant TuMV and ZYMV, respectively. We have found that the maintenance of the charge of the amino acids in the FRNK motif of HC-Pro is required for symptom expression. Reduced charge (FRNA, FRNL) lessen virus symptoms, and maintain the suppression of RNA silencing. The FRNK motif is involved in binding of small RNA species including microRNAs (miRNA) and short interfering RNAs (siRNA). This binding activity mediated by the FRNK motif has a role in protecting the viral genome from degradation by the host RNA silencing system. However, it also provides a mechanism by which the FRNK motif participates in inducing the symptoms of viral infection. Small RNA species, such as miRNA and siRNA, can regulate the functions of plant genes that affect plant growth and development. Thus, this binding activity suggests a mechanism by which ZYMVHC-Pro can interfere with plant development resulting in disease symptoms. Because the host genes regulated by small RNAs are known, we have identified candidate host genes that are expected to play a role in symptoms when their regulation is disrupted during viral infections. As a result of this work, we have a better understanding of the FRNK amino acid motif of HC-Pro and its contribution to the functions of HC-Pro, and we have identified plant genes that potentially contribute to symptoms of virus infected plants when their expression becomes misregulated during potyviral infections. The results set the stage to establish the roles of specific host genes in viral pathogenicity. The potential benefits include the development of novel strategies for controlling diseases caused by viruses, methods to ensure stable expression of transgenes in genetically improved crops, and improved potyvirus vectors for expression of proteins or peptides in plants.
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Wicker, Louise, e Nissim Garti. Entrapment and controlled release of nutraceuticals from double emulsions stabilized by pectin-protein hybrids. United States Department of Agriculture, outubro de 2004. http://dx.doi.org/10.32747/2004.7695864.bard.
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Original Objectives Specific objectives are to: (1) modify charge and hydrophobicity of pectins to improve emulsion stabilizing properties (2) develop emulsions that can be sterically stabilized using modified pectins and/or pectin/protein hybrids (3) obtain submicronal inner emulsion droplets (10-50 nanometers) with small and monodispersed double emulsion (1-2 μm) droplets with long-term stability (possibly by emulsified microemulsions) and (4) trigger and control the release at will. Background Methodology for encapsulation and controlled release of selected addenda, e.g. drugs, vitamins, phytochemicals, flavors, is of major impact in the food industries. Stable double emulsions with desired solubilization and release properties of selected addenda are formed using charge modified pectin or pectin-protein hybrids. Major conclusions, solutions, achievements * We developed methodology to isolate PME isozymes and prepared modified pectins in sufficient quantity to characterize, form single and double emulsions and test stability. *Amino acid sequence of PME isozymes was estimated and will facilitate cloning of PME for commercial application * The contribution of total charge and distribution of charge of modified pectin was determined *Soluble complexes or modified pectins and whey isolates are formed * Stable W/O/W double emulsions were formed that did not cream, had small particle size * Inner phase of double emulsions are nano-sized and stable. These new structures were termed emulsified microemulsions (EME) * Release of bioactives were controlled between a few days to months depending on layering on droplets by hybrids * Commercial testing by Israeli company of stability and release of Vitamin C showed good chemical stability Implications Resolved the major stability limitation of W/O/W emulsions. Resolved the questions regarding citrus PMEs and tailored pilot scale modification of pectins.
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Wong, Eric A., e Zehava Uni. Nutrition of the Developing Chick Embryo: Nutrient Uptake Systems of the Yolk Sac Membrane and Embryonic Intestine. United States Department of Agriculture, junho de 2012. http://dx.doi.org/10.32747/2012.7697119.bard.
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We have examined the developmental changes in composition, amount, and uptake of yolk nutrients (fat, protein, water and carbohydrates) and the expression ofnutrient transporters in the yolk sac membrane (YSM) from embryonic day 11 (Ell) to 21 (E21) and small intestine from embryonic day 15 (E15) to E21 in embryos from young (22-25 wk) and old (45-50 wk) Cobb and Leghorn breeder flocks. The developmental expression profiles for the peptide transporter 1 (PepTl), the amino acid transporters, EAAT3, CAT-1 and BOAT, the sodium glucose transporter (SGLTl), the fructose transporter (GLUT5), the digestive enzymes aminopeptidase N (APN) and sucraseisomaltase (SI) were assayed by the absolute quantification real time PCR method in the YSM and embryonic intestine. Different temporal patterns of expression were observed for these genes. The effect of in ovo injection of peptides (the dipeptide Gly-Sar, purified peptides, trypsin hydrolysate) on transporter gene expression has been examined in the embryonic intestine. Injection of a partial protein hydrolysate resulted in an increase in expression of the peptide transporter PepT2. We have initiated a transcriptome analysis of genes expressed in the YSM at different developmental ages to better understand the function of the YSM.
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Whitham, Steven A., Amit Gal-On e Victor Gaba. Post-transcriptional Regulation of Host Genes Involved with Symptom Expression in Potyviral Infections. United States Department of Agriculture, junho de 2012. http://dx.doi.org/10.32747/2012.7593391.bard.
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Understanding how RNA viruses cause disease symptoms in their hosts is expected to provide information that can be exploited to enhance modern agriculture. The helper component-proteinase (HC-Pro) protein of potyviruses has been implicated in symptom development. Previously, we demonstrated that symptom expression is associated with binding of duplex small-interfering-RNA (duplex-siRNA) to a highly conserved FRNK amino acid motif in the HC-Pro of Zucchini yellow mosaic virus (ZYMV). This binding activity also alters host microRNA (miRNA) profiles. In Turnip mosaic virus (TuMV), which infects the model plant Arabidopsis, mutation of the FRNK motif to FINK was lethal providing further indication of the importance of this motif to HC-Pro function. In this continuation project, our goal was to further investigate how ZYMV and TuMV cause the mis-expression of genes in cucurbits and Arabidopsis, respectively, and to correlate altered gene expression with disease symptoms. Objective 1 was to examine the roles of aromatic and positively charged residues F164RNH and K215RLF adjacent to FR180NK in small RNA binding. Objective 2 was to determine the target genes of the miRNAs which change during HC-Pro expression in infected tissues and transgenic cucumber. Objective 3 was to characterize RNA silencing mechanisms underlying differential expression of host genes. Objective 4 was to analyze the function of miRNA target genes and differentially expressed genes in potyvirus-infected tissues. We found that the charged K/R amino acid residues in the FKNH and KRLF motifs are essential for virus viability. Replacement of K to I in FKNH disrupted duplex-siRNA binding and virus infectivity, while in KRLF mutants duplex-siRNA binding was maintained and virus infectivity was limited: symptomless following a recovery phenomenon. These findings expanded the duplex-siRNA binding activity of HC-Pro to include the adjacent FRNK and FRNH sites. ZYMV causes many squash miRNAs to hyper-accumulate such as miR166, miR390, mir168, and many others. Screening of mir target genes showed that only INCURVATA-4 and PHAVOLUTA were significantly upregulated following ZYMVFRNK infection. Supporting this finding, we found similar developmental symptoms in transgenic Arabidopsis overexpressing P1-HC-Pro of a range of potyviruses to those observed in miR166 mutants. We characterized increased transcription of AGO1 in response to infection with both ZYMV strains. Differences in viral siRNA profiles and accumulation between mild and severe virus infections were characterized by Illumina sequencing, probably due to the differences in HC-Pro binding activity. We determined that the TuMV FINK mutant could accumulate and cause symptoms in dcl2 dcl4 or dcl2 dcl3 dcl4 mutants similar to TuMV FRNK in wild type Arabidopsis plants. These dcl mutant plants are defective in antiviral defenses, and the results show that factors other than HC-ProFRNK motif can induce symptoms in virus-infected plants. As a result of this work, we have a better understanding of the FRNK and FKNH amino acid motifs of HC-Pro and their contributions to the duplex-siRNA binding functions. We have identified plant genes that potentially contribute to infectivity and symptoms of virus infected plants when they are mis-expressed during potyviral infections. The results establish that there are multiple underlying molecular mechanisms that lead viral pathogenicity, some dependent on HC-Pro. The potential benefits include the development of novel strategies for controlling diseases caused by viruses, methods to ensure stable expression of transgenes in genetically improved crops, and improved potyvirus vectors for expression of proteins or peptides in plants.
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Singhvi, Punit, Javier García Mainieri, Hasan Ozer e Brajendra Sharma. Rheology-Chemical Based Procedure to Evaluate Additives/Modifiers Used in Asphalt Binders for Performance Enhancements: Phase 2. Illinois Center for Transportation, junho de 2021. http://dx.doi.org/10.36501/0197-9191/21-020.
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The increased use of softer binders in Illinois over the past decade is primarily attributed to the increased use of recycled materials in asphalt pavement construction. The shift in demand of using PG 58-28 over PG 64-22 has resulted in potential alternative methods to produce softer binders more economically using proprietary products. However, there are challenges in using these proprietary products for asphalt modification because of uncertainty in their long-term performance and significant variability in binder chemistry. The current SuperPave performance grading specification for asphalt binders is insufficient in differentiating binders produced from these modifiers. Therefore, the objective of this study is to evaluate the performance of various softener-type asphalt binder modifiers using a wide array of rheological and chemistry tests for their integration into the Illinois Department of Transportation’s material specifications. The small-strain rheological tests and their parameters allowed for consistent grouping of modified binders and can be used as surrogates to identify performing and nonperforming asphalt binders. A new parameter, Δ|G*|peak τ, was developed from the linear amplitude sweep test and showed potential to discriminate binders based on their large-strain behavior. Chemistry-based parameters were shown to track aging and formulation changes. The modifier sources were identified using fingerprint testing and were manifested in the modified binder chemical and compositional characteristics. The two sources of base binders blended with the modifiers governed the aging rate of the modified binders. Mixture performance testing using the Illinois Flexibility Index Test and the Hamburg Wheel-Track Test were consistent with the rheological and chemical findings, except for the glycol amine-based modified binder, which showed the worst cracking performance with the lowest flexibility index among the studied modifiers. This was contrary to its superior rheological performance, which may be attributed to lower thermal stability, resulting in high mass loss during mixing. According to the characterization of field-aged binders, laboratory aging of two pressurized aging vessel cycles or more may represent realistic field aging of 10 to 15 years at the pavement surface and is able to distinguish modified binders. Therefore, an extended aging method of two pressurized aging vessel cycles was recommended for modified binders. Two different testing suites were recommended for product approval protocol with preliminary thresholds for acceptable performance validated with field-aged data.
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Yalovsky, Shaul, e Julian Schroeder. The function of protein farnesylation in early events of ABA signal transduction in stomatal guard cells of Arabidopsis. United States Department of Agriculture, janeiro de 2002. http://dx.doi.org/10.32747/2002.7695873.bard.
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Loss of function mutations in the farnesyltransferase β subunit gene ERA1 (enhanced response to abscisic acid), cause abscisic acid hypersensitivity in seedlings and in guard cells. This results in slowed water loss of plants in response to drought. Farnesyltransferase (PFT) catalyses the attachment of the 15-carbon isoprenoid farnesyl to conserved cysteine residues located in a conserved C-terminal domain designated CaaX box. PFT is a heterodimeric protein comprised of an a and b sununits. The a subunit is shared between PFT and geranylgeranyltransferase-I (PGGTI) which catalyses the attachemt of the 20-carbon isoprenoid geranylgeranyl to CaaX box proteins in which the last amino acid is almost always leucine and in addition have a polybasic domain proximal to the CaaL box. Preliminary data presented in the proposal showed that increased cytoplasmic Ca2+ concentration in stomal guard cells in response to non-inductive ABA treatements. The goals set in the proposal were to characterize better how PFT (ERA1) affects ABA induced Ca2+ concentrations in guard cells and to identify putative CaaX box proteins which function as negative regulators of ABA signaling and which function is compromised in era1 mutant plants. To achieve these goals we proposed to use camelion Ca2+ sensor protein, high throughput genomic to identify the guard cell transcriptome and test prenylation of candidate proteins. We also proposed to focus our efforts of RAC small GTPases which are prenylated proteins which function in signaling. Our results show that farnesyltransferaseprenylates protein/s that act between the points of ABA perception and the activation of plasma membrane calcium influx channels. A RAC protein designated AtRAC8/AtRop10 also acts in negative regulation of ABA signaling. However, we discovered that this protein is palmitoylated and not prenylated although it contains a C-terminal CXXX motif. We further discovered a unique C-terminal sequence motif required for membrane targeting of palmitoylatedRACs and showed that their function is prenylation independent. A GC/MS based method for expression in plants, purification and analysis of prenyl group was developed. This method would allow highly reliable identification of prenylated protein. Mutants in the shared α subunit of PFT and PGGT-I was identified and characterized and was shown to be ABA hypersensitive but less than era1. This suggested that PFT and PGGT-I have opposing functions in ABA signaling. Our results enhanced the understanding of the role of protein prenylation in ABA signaling and drought resistance in plants with the implications of developing drought resistant plants. The results of our studies were published 4 papers which acknowledge support from BARD.