Relevant bibliographies by topics / Chemical activity

Academic literature on the topic 'Chemical activity'

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Published: 4 June 2021
Last updated: 3 February 2022

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Journal articles on the topic "Chemical activity"

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Brovarska, O. S., L. D. Varbanets, and S. V. Kalinichenko. "Chemical Characterization and Biological Activity of Escherichia coli Lipopolysaccharides." Mikrobiolohichnyi Zhurnal 82, no. 6 (November 30, 2020): 35–42. http://dx.doi.org/10.15407/microbiolj82.06.035.

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Lipopolysaccharides (LPS) are specific components of the cell envelope of gram-negative bacteria, located at the external surface of their outer membrane and performing a number of important physicochemical and biological functions. The widespread in nature are representatives of Enterobacteriaceae family. Among them there are saprotrophic, useful human symbionts, as well as causative agents of acute intestinal infections. The role of saprophytic intestinal microbiota is not limited only to its participation in the digestion process. The endotoxin released as a result of self-renewal of the cell pool of Escherichia coli partially enters the portal blood and performs antigenic stimulation of the macroorganism. In addition, a small amount of endotoxin can also be released by live gram-negative bacteria, which, given the large population of E. coli in the intestine, can create a sufficiently high concentration of endotoxin. Aim. The study of composition and biological activity of lipopolysaccharides of new E. coli strains, found in the human body. Methods. The objects of investigation were strains of Escherichia coli, isolated from healthy patients at the epidemiological center in Kharkiv. Lipopolysaccharides were extracted from dried cells by 45% phenol water solution at 65–68°С by Westphal and Jann method. The amount of carbohydrates was determined by phenol-sulfuric method. Carbohydrate content was determined in accordance to the calibration curve, which was built using glucose as a standard. The content of nucleic acids was determined by Spirin method, protein − by Lowry method. Serological activity of LPS was investigated by double immunodiffusion in agar using the method of Ouchterlony. Results. In all studied E. coli LPS (2884, 2890, 2892), glucose was dominant monosaccharide (40.5, 41.1, 67.3%, respectively). LPS also contained rhamnose (1.8, 22.9, 1.6%, respectively), ribose (3.5, 6.1, 3.6%, respectively) and galactose (4.1, 20.2, 18.3%, respectively). E. coli 2884 LPS also contained arabinose (1.0%) and mannose (44.8%), while E. coli strains 2890 and 2892 LPS contained heptose (9.7 and 7.8%, respectively). Lipid A composition was presented by fatty acids with a carbon chain length from C12 to C18. As the predominant components were 3-hydroxytetradecanoic (39.2–51.3%) as well as tetradecanoic (23.1–28.5%), dodecanoic (8.9–10.9%), hexadecanoic (4.3–7.2%) and octadecanoic (1.8–2.4%) acids. Unsaturated fatty acids: hexadecenoic (2.0–17.9%) and octadecenoic (3.4–4.2%) have been also identified. It was found that octadecanoic and octadecenoic acids were absent in the LPS of 2884 and 2892 strains, respectively. In SDS-PAAG electrophoresis, a bimodal distribution typical for S-forms of LPS was observed. The studied LPS were toxic and pyrogenic. Double immunodiffusion in agar by Ouchterlony revealed that the tested LPS exhibited an antigenic activity in the homologous system. In heterologous system E. coli 2892 LPS had cross reactivity with LPS of E. coli 2890 and М-17. Since the structure of the O-specific polysaccharide (OPS) of E. coli M-17 was established by us earlier, the results of serological reactions make it possible to suggest an analogy of the E. coli 2892 and 2890 OPS structures with that of E. coli М-17 and their belonging to the same serogroup. Conclusions. The study of the composition and biological activity of LPS of new strains of Escherichia coli 2884, 2890 and 2892, isolated from the body of almost healthy patients, expands our knowledge about the biological characteristics of the species.
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Gao, Yang, Huiyi Huang, Hongyi Zhao, Houqiang Xia, Miao Sun, Pengcheng Li, Cangsong Zheng, Helin Dong, and Jingran Liu. "Phosphorus affects enzymatic activity and chemical properties of cotton soil." Plant, Soil and Environment 65, No. 7 (August 1, 2019): 361–68. http://dx.doi.org/10.17221/296/2019-pse.

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Pot experiments were conducted in 2017 with two cotton cultivars (CCRI 79 and LMY 28) and three phosphorus (P) levels: 3, 8 and 12 mg P<sub>2</sub>O<sub>5</sub>/kg as P<sub>0</sub>, P<sub>1</sub> and P<sub>2</sub>, respectively. In this study, the soil water-soluble organic carbon content increased as the soil available P (AP) increased, while there were no significant variations for soil total organic matter content among the three AP levels. The activities of invertase, cellulase and urease in cotton soil decreased significantly in the P0. There were positive correlations between invertase and cellulose activities with soil organic carbon and inorganic-nitrogen (N); these correlated negatively with soil C/N ratio and AP level. In addition, high soil AP can raise soil AP and enhance alkaline phosphatase activity, which had a significant negative relationship with the soil C/P ratio. Urease activity had a significant positive relationship with soil NH<sub>4</sub><sup>+</sup>-N, C/P and N/P, as well as a negative correlation with soil C/N. Moreover, soil NH<sub>4</sub><sup>+</sup>-N and NO<sub>3</sub><sup>–</sup>-N in the P<sub>1</sub> and P<sub>2</sub> were lower than in the P<sub>0</sub>, which might be an effect of high AP on soil N availability.
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Daglia, M., A. Papetti, and G. Gazzani. "Green and roasted coffee antiradical activity stability in chemical systems." Czech Journal of Food Sciences 22, SI - Chem. Reactions in Foods V (January 1, 2004): S191—S194. http://dx.doi.org/10.17221/10658-cjfs.

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The stability to storage at different temperature and oxygen exposure of green and roasted coffee either as coffee beans or as ground coffee antiradical activity, was evaluated. The results showed that the coffee solution antihydroxyl radical activity was constant, independently from the coffee species, from the roasting process, and moreover from the type of storage conditions, suggesting that temperature and oxygen exposure did not affect this antiradical activity. With regard to antiperoxyl radical activity, all green coffee solutions showed remarkable and stable activity. Conversely, the roasted coffee beans and roasted and ground coffee antiperoxyl radical activity started to increase after three month of storage, suggesting that Maillard reaction products affect the stability of such antiradical property.
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Oranusi, Solomon, Adeola Onibokun, Oluwatoyosi Afolabi, Chineme Okpalajiaku, Anita Seweje, Bunmi Olopade, and Yemisi Obafemi. "Chemical, microbial and antioxidant activity of Cola lepidota K. Schum fruits." Czech Journal of Food Sciences 38, No. 1 (February 29, 2020): 11–19. http://dx.doi.org/10.17221/360/2018-cjfs.

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This research was to investigate the chemical composition, antioxidant activity, and microbial profiles of Cola lepidota fruits. One hundred grams each of the fruit exocarp, mesocarp and endocarp were blended and analyses were carried out by the following standard methods. Active acidity and vitamin C contents were 5.5 and 6.34 mg 100 g<sup>–1</sup> in endocarp, 4.5 and 14.39 mg 100 g<sup>–1</sup> in mesocarp and 6.7 and 10.02 mg 100 g<sup>–1</sup> for exocarp. Moisture and carbohydrate contents of 12.31 and 68.72% were in the mesocarp while protein and crude fibre contents of 8.13 and 26.18% were in the exocarp and endocarp. Iron (Fe), zinc (Zn) and manganese (Mn) contents were 1.79, 0.27 and 0.57 mg 100 g<sup>–1</sup> in exocarp while lead (Pb), cadmium (Cd) and chromium (Cr) were absent in the endocarp. Predominant isolates were Aspergillus niger, Saccharomyces cerevisiae, Aspergillus flavus, Bacillus, Staphylococcus and Pseudomonas species. C. lepidota had no antimicrobial effect against the tested organisms. Tannins, flavonoids, terpenoids, phenols, coumarins and anthocyanins were present while alkaloids, quinolones, glycosides, steroids and cardiac glycosides were absent. The fruit was observed to have antioxidant property by hydrogen peroxide scavenging activity. This study presents C. lepidota as good for human consumption and can be exploited for animal feed production.
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Vasylyshyna, Olena, and Olena Vasylyshyna. "Cherry chemical composition and antioxidant activity under freezing comprehensive relations assessment." Foods and Raw Materials 6, no. 2 (December 20, 2018): 296–304. http://dx.doi.org/10.21603/2308-4057-2018-2-296-304.

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Cherry is a successful combination of sugars, acids, attractive color and taste. However, its shelf life is limited and can be prolonged only with the help of new freezing technologies. Therefore, the gool of this work was to investigate changes in component composition of fresh and frozen cherry. The objects of the research were cherries of the varieties of Shpanka and Lotovka. The studies were carried out with cherries grown in the Central region of Ukraine at the Department of Technology of storage and processing of fruits and vegetables at Uman National Horticulture University. For cherries of both varieties were kept in 20% sugar solution with the addition of 4% ascorutin 1% chitosan for 30 minutes, dried with air flow, frozen at –25°C, packed in 0.5 kg plastic bags, and stored at ‒18°C. For control purposes, nontreated cherries were packed in plastic bags of respective volume. According to the research, preprocessing with 20% sugar solution with the addition of 1% chitosan contributes to preservation of quality and biological value of frozen cherries. Thus antioxidant activity in frozen cherries of Shpanka and Lotovka varieties is 27 and 18 mmol/dm3, ascorbic acid content – 17.6 and 20 mg/100g. So the indexes of quality of cherries for freezing are interrelated and constitute one correlation pattern in which the major index indicator is the content of dry soluble substance and antioxidant activity.
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Souza, Elizângela Maria, Renilde Cordeiro Souza, Mateus Matiuzzi Costa, Carlos Garrido PINHEIRO, Berta Maria HEINZMANN, and Carlos Eduardo COPATTI. "Chemical composition and evaluation of the antimicrobial activity of two essential oils." Boletim do Instituto de Pesca 44, no. 2 (June 6, 2018): 1–4. http://dx.doi.org/10.20950/1678-2305.2018.321.

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Zhirkova, Е. V., M. V. Skorokhodova, V. V. Martirosyan, E. F. Sotchenko, V. D. Malkina, and T. A. Shatalova. "CHEMICAL COMPOSITION AND ANTIOXIDANT ACTIVITY OF CORN HYBRIDS GRAIN OF DIFFERENT PIGMENTATION." Food and Raw Materials 4, no. 2 (December 30, 2016): 85–91. http://dx.doi.org/10.21179/2308-4057-2016-2-85-91.

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Devi, Ch Kethani, and Dr D. Gopala Krishna. "Phyto Chemical Screening and Anti-Microbial Activity of Musa Paradisiaca-Fruit Peel." Indian Journal of Applied Research 3, no. 7 (October 1, 2011): 248–49. http://dx.doi.org/10.15373/2249555x/july2013/77.

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Teles, Rogerio De Mesquita, Victor Elias Mouchrek Filho, and Adenilde Nascimento. "Chemical Composition and Antibacterial Activity of Essential Oil of Aniba duckei Kosterman." International Journal of Life-Sciences Scientific Research 4, no. 2 (March 2018): 1657–62. http://dx.doi.org/10.21276/ijlssr.2018.4.2.7.

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TSUNAKAWA, Sukenari. "Chemical reaction and research activity." Journal of Japan Institute of Light Metals 35, no. 12 (1985): 661–62. http://dx.doi.org/10.2464/jilm.35.661.

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Dissertations / Theses on the topic "Chemical activity"

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Trevenen, S. J. "Redox switching of chemical activity." Thesis, University of Newcastle Upon Tyne, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.323703.

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Elsnini, Ruwida Mansour. "Chemical characterization and biological activity of African propolis." Thesis, University of Strathclyde, 2016. http://digitool.lib.strath.ac.uk:80/R/?func=dbin-jump-full&object_id=28825.

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Propolis or bee glue, is collected by bees and contains secondary metabolites largely derived from trees or shrubs; it has been used traditionally as a natural remedy with a wide range of biological activities. Its chemical composition is highly complex and variable, and it has been studied in detail worldwide except in Africa. This study investigated the chemical composition and activity of African propolis against blood stream form of Trypanosoma brucei, the causative agent for sleeping sickness that threatens a large population of both humans and animals in sub-Saharan Africa. Extracts of propolis samples (n=12) collected from different regions in Nigeria and one sample collected from South Africa were chemically profiled by using various analytical techniques. These included high performance liquid chromatography (HPLC), coupled with different detection systems including evaporative light scattering detection (ELSD), ultraviolet detection (UV), and high resolution mass spectrometry (HRMS), along with gas chromatography- mass spectrometry (GC-MS) and proton-nuclear magnetic resonance (1H-NMR).Principal components analysis (PCA) of the processed LC-MS data collected was used in order to characterize samples according to their chemical composition. PCA demonstrated the uniqueness in chemical composition of some samples that were also active against Trypanosoma brucei. Therefore, the study proceeded to investigate in detail four samples collected mainly from the southern part of Nigeria. An optimized medium pressure chromatographic technique was used to isolate some of the component(s) responsible for the anti-trypanosomal activity. Two samples collected from Rivers State Nigeria had a different appearance from the rest of the propolis samples, being red in colour and had the highest trypanocidal activity (EC50=4.2 and 6.9 μg/mL) respectively. Their chemical composition was comparable to that of Brazilian red propolis. Fractionation work led to the isolation of ten phenolic compounds including calycosin, liquiritigenen, pinocembrin, vestitol, medicarpin, 8-prenylnaringenin, 6-prenylnaringenin, propolin D, macarangin and a new benzofuran. All compounds structurally elucidated by 1D and 2D Nuclear Magnetic Resonance (NMR) spectroscopy and LC-MSn. Some compounds showed strong inhibitory activity against trypanosomes such as medicarpin (MIC=11.5 μM) and propolin D (MIC=7.4 μM), macarangin (EC50 =18.5 μM), 8-prenylnaringenin (EC50= 17.9 μM), and vestitol (EC50= 30.5 μM). The new benzofuran was moderately active with (EC50=58.01 μM). Fractionation of the propolis sample collected from the Ugelli/Delta sample led to isolation of three compounds 1,3,7-trihydroxy-2,8-di-(3-methylbut-2-enyl) xanthone, 1,3,7-trihydroxy-4,8-di-(3-methylbut-2-enyl) xanthone and a new xanthone. These compounds were tested against T. brucei and presented high activities of EC50= 3.9, 11.04, 14.7 μM respectively. Triterpenes were the main fingerprint compounds in a sample collected from Ijebu-Ode/Ogun; three compounds were isolated and elucidated as ambonic acid, mangiferonic acid and α-amyrin. These compounds had EC50 values against T. brucei of 39.5, 25.5 and 20.9 μM respectively. Finally, sample D46SA from South Africa was found to contain mainly flavonols and diterpenic acids; three compounds pinocembrin, acetylimbricatolic acid and (-)-pimara-8 (14), 15-dien-19-oic acid were isolated and tested. All were moderately active against T. brucei.with MIC ranging from 41.4-137.3 μMIn conclusion, this work has proved the variabiliy of propolis collected even from the same region and the widespread activity of propolis against (blood stream form) T. brucei. It is likely that some of the propolis samples contain compounds with even higher activity that have not yet been isolated.
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Cadorette, Veronica R. "Chemical investigation of Dicranum fulvum for anticancer activity." Thesis, Virginia Tech, 1989. http://hdl.handle.net/10919/44706.

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Biological screening of extracts of various bryophytes showed that the species Dicranum fulvum gave extracts with activity in both in vitro and in vivo bioassays. This plant was thus selected for extraction and fractionation, monitored by iin vitro bioassays.

Isolation was guided by a combination of bioassay and chemical methods, and led to the isolation of three compounds, betulin, 9,l9- cyclolanostâ 23â eneâ 3,25â diol, and B-sitosterol. Purification was achieved by open column, flash column, gel filtration, thin layer chromatography, the chromatotron and crystallization.

The isolated compounds were identified by comparisons of spectroscopic data with those of authentic samples and the matching of experimental and literature melting points and optical rotations.


Master of Science
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Dambuza, Ntokozo Shirley. "Antimalarial activity and pharmacokinetic properties of new chemical entities." Doctoral thesis, University of Cape Town, 2013. http://hdl.handle.net/11427/3278.

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Hameed, Bassim Hamid. "Kinetics and activity of C←4 -hydrogenation catalysts." Thesis, University of Salford, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.306170.

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Izquierdo, García Eduardo. "Chemical approaches to the study of the ceramide synthase activity." Doctoral thesis, Universitat de Barcelona, 2020. http://hdl.handle.net/10803/671426.

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Sphingolipids (SLs) are one of the major classes of lipids in eukaryotes. In addition to being essential structural components of cell membranes, SLs also play capital roles as signalling molecules. Ceramides (Cer) are a family of bioactive SLs consisting of a long chain base (LCB), known as the sphingoid base, linked to a fatty acid (FA) of variable chain length via an amide bond. Due to their metabolic inter-relations with other SL species, Cer are considered key intermediates in the SL pathway. Cer are important second messengers in several cellular processes including apoptosis, autophagy, cell differentiation and sensescence. Ceramide synthases (CerS) are a group of enzymes, primarily localised at the endoplasmic reticulum, that catalyse the N–acylation of sphingoid bases such as sphingosine (So) and dihydrosphingosine (dhSo), using acyl CoA thioesters of variable chain lengths, to afford Cer and dihydroceramides (dhCer), respectively. Six isoforms of CerS (CerS1–6) have been identified in mammals. Each CerS isoform utilizes a small subset of FA-CoAs of defined chain lengths and, thus, each of them produces specific Cer populations. In the recent years, it has become apparent that Cer with different acyl chains vary in their biophysical properties and in the signalling pathways they participate. Furthermore, Cer with defined acyl chain lengths have been found to be implicated in the onset of a variety of human diseases, including cancer, type-2 diabetes mellitus, Alzheimer’s disease, multiple sclerosis and cardiomyopathy. In this context, the development of appropriate tools to study the activity of CerS enzymes, which is crucial to decipher the molecular mechanisms by which Cer elicit their effects, was the ultimate goal of the present doctoral thesis. The first part of this thesis was devoted to the development of a new CerS activity assay based on the Förster Resonance Energy Transfer (FRET) phenomenon. To that end, we designed and synthesized a series of fluorescently labelled (or labelable) 1-deoxy sphingoid probes derived from spisulosine, a small library of clickable FA analogues of different chain lengths, and a collection of bicyclo[6.1.0]nonyne (BCN) or 1,2,4,5-tetrazine (Tz) based fluorescent reagents. The absorption and fluorescence emission properties of these compounds was thoroughly studied in various solvents by means of cuvette-based experiments. Based on these studies, we anticipated that a highly efficient FRET process would take place between the donor-acceptor fluorophore pairs that had been selected, namely MCC/NBD and NBD/NR. Next, the metabolic incorporation of the different spisulosin-based probes and the FA analogues was evaluated in various biological contexts. Mass spectrometry analysis evidenced an extensive metabolization of the synthetic LCB probes and the FA analogues by CerS enzymes to form the corresponding Cer metabolites. Unfortunately, the FA analogues were also incorporated into other lipidic metabolic pathways, resulting in the generation of a strong fluorescence background after the fluorescent labelling reactions. Our different attempts to solve this issue were unfruitful and, thus, the development of the FRET based fluorescence assay to determine the CerS activity could not be achieved. The second part of this thesis was aimed at the development of new click-formed proteolysis targeting chimeras (CLIPTACs) targeting the ubiquitination and proteasomal degradation of CerS, as an alternative to small molecule inhibitors for the modulation of the CerS activity. To this end, we designed and synthesized four BCN derivatives containing known ligands for recruiting different E3 ubiquitin ligases. These BCN-tagged E3 ligase recruiters will be used in future studies in combination with an azido-functionalized analogue of the CerS substrate Jaspine B to obtain the desired CLIPTACs.
Los esfingolípidos (SLs) son una de las principales categorías de lípidos presentes en los organismos eucariotas. Los SL no sólo son componentes estructurales esenciales de las membranas celulares, sino que también actúan como moléculas señalizadoras. Las ceramidas (Cer) son una tipología de SL que están formadas por una base esfingoide y una cadena de ácido graso de longitud variable unidos a través de un enlace amida. Las Cer participan como segundos mensajeros en procesos celulares como la apoptosis, la autofagia, la diferenciación celular y la senescencia. Las ceramida sintasas (CerS) son un grupo de enzimas del retículo endoplasmático que catalizan la N-acilación de bases esfingoides, como la esfingosina, utilizando acil-CoAs de distintas longitudes, para dar Cer. En los mamíferos se han descrito seis isoformas de la CerS y cada una de ellas tiene preferencia por un pequeño grupo de ácidos grasos de longitud de cadena definida, por lo que cada una produce perfiles de Cer característicos. En los últimos años se ha visto que la longitud de la cadena acilo de las Cer influye en sus propiedades biofísicas y en las cascadas de señalización en las que participan. Además, se sabe que ciertas Cer están involucradas en el desarrollo de distintas enfermedades como el cáncer, la diabetes, el Alzheimer o la esclerosis múltiple. En este sentido, el desarrollo de herramientas adecuadas para el estudio de la actividad de CerS es fundamental para descifrar los mecanismos moleculares a través de los cuáles actúan las Cer, siendo este el objetivo principal que se persiguió en la presente tesis doctoral. La primera parte de la tesis se centró en el desarrollo de un nuevo ensayo para determinar la actividad CerS por medio del fenómeno de FRET. Para ello, se diseñaron y sintetizaron una serie de sondas esfingoides derivadas de la espisulosina, una pequeña quimioteca de análogos de ácidos grasos “clicables” de distintas longitudes de cadena y una colección de reactivos fluorescentes marcados con un grupo biciclo[6.1.0]nonino (BCN) o 1,2,4,5-tetrazina (Tz). Las propiedades de absorción y emisión de fluorescencia de estos compuestos fueron estudiadas en varios disolventes a través de experimentos “en cubeta”. En base a estos experimentos anticipamos que las parejas de fluoróforos seleccionadas eran adecuadas para su uso en experimentos de FRET. A continuación, se evaluó la incorporación metabólica de las distintas sondas esfingoides y de los varios análogos de ácidos grasos en medios biológicos. Los estudios de lipidómica mostraron que tanto las sondas como los análogos de ácidos grasos eran procesados por las CerS para dar las Cer correspondientes. Sin embargo, los análogos de ácidos grasos también entraron en otras rutas metabólicas de los lípidos dando lugar a un elevado ruido de fondo tras la reacción de marcaje de fluorescencia. Nuestros intentos para solventar este problema fueron en vano y, por tanto, finalmente no fue posible la implementación del ensayo de fluorescencia para medir la actividad CerS. En la segunda parte de la tesis se propuso el desarrollo de nuevos CLIPTACs dirigidos a la degradación de CerS, como alternativa a los inhibidores clásicos para la modulación de la actividad CerS. Para ello se diseñaron y sintetizaron cuatro derivados de BCN que contuvieran un ligando para reclutar distintos enzimas E3 ligasas de ubiquitina. Estos reclutadores de E3 ligasa serán utilizados en un futuro en combinación con un derivado de la Jaspina B, un análogo del sustrato de las CerS, para obtener los CLIPTACs deseados.
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Andersson, Patrik. "Physico-chemical characteristics and quantitative structure-activity relationships of PCBs." Doctoral thesis, Umeå University, Chemistry, 2000. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-17.

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The polychlorinated biphenyls (PCBs) comprise a group of 209 congeners varying in the number of chlorine atoms and substitution patterns. These compounds tend to be biomagnified in foodwebs and have been shown to induce an array of effects in exposed organisms. The structural characteristics of the PCBs influence their potency as well as mechanism of action. In order to assess the biological potency of these compounds a multi-step quantitative structure-activity relationship (QSAR) procedure was used in the project described in this thesis.

The ultraviolet absorption (UV) spectra were measured for all 209 PCBs, and digitised for use as physico-chemical descriptors. Interpretations of the spectra using principal component analysis (PCA) showed the number of ortho chlorine atoms and para-para substitution patterns to be significant. Additional physico-chemical descriptors were derived from semi-empirical calculations. These included various molecular energies, the ionisation potential, electron affinity, dipole moments, and the internal barrier of rotation. The internal barrier of rotation was especially useful for describing the conformation of the PCBs on a continuous scale.

In total 52 physico-chemical descriptors were compiled and analysed by PCA for the tetra- to hepta-chlorinated congeners. The structural variation within these compounds was condensed into four principal properties derived from a PCA for use as design variables in a statistical design to select congeners representative for these homologue-groups. The 20 selected PCBs have been applied to study structure-specific biochemical responses in a number of bioassays, and to study the biomagnification of the PCBs in various fish species.

QSARs were established using partial least squares projections to latent structures (PLS) for the PCBs potency to inhibit intercellular communication, activate respiratory burst, inhibit dopamine uptake in synaptic vesicles, compete with estradiol for binding to estrogen receptors, and induce cytochrome P4501A (CYP1A) related activities. By the systematic use of the designed set of PCBs the biological potency was screened over the chemical domain of the class of compounds. Further, sub-regions of highly potent PCBs were identified for each response measured. For risk assessment of the PCBs potency to induce dioxin-like activities the predicted induction potencies (PIPs) were calculated. In addition, two sets of PCBs were presented that specifically represent congeners of environmental relevance in combination with predicted potency to induce estrogenic and CYP1A related activities.

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Alrushaid, Samaa. "Chemical reactivity and biological activity of bethoxazin, an industrial microbicide." Bioorganic & Medicinal Chemistry, 2012. http://hdl.handle.net/1993/23627.

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Bethoxazin is a broad spectrum industrial biocide with commercial applications as a material preservative; however its mechanism of action has not been investigated. In this study, the chemical reactivity of bethoxazin towards biologically important nucleophiles was assessed with UV-Vis spectroscopy. Bethoxazin reacted with molecules containing free sulfhydryl groups such as glutathione and human serum albumin but not with amino, acetate or phenol containing compounds. Bethoxazin was shown to potently inhibit the growth of the K562 human cancer cell line with an IC50 value in the micromolar range. The sulfydryl fluorescent label ThioGlo-1 was used to investigate the biological effects of bethoxazin in K562 cells and explore its mechanism of action. Bethoxazin inhibited the formation of covalent adducts in K562 cells between the free sulfhydryl group of biomolecules and ThioGlo-1, implying that bethoxazin reacts with molecules containing free sulfhydryl groups. Likewise, when glutathione was depleted in K562 cells, by buthionine sulfoximine, high concentrations of bethoxazin were able to inhibit the formation of covalent adducts between sulfhydryl biomolecules and ThioGlo-1. The growth inhibition assay (MTS) was used to investigate the effect of continuous bethoxazin treatment versus wash out in K562 cells. The MTS assay revealed a reduction in the potency of bethoxazin due to the wash out effect, suggesting that the growth inhibition effects of bethoxazin are likely not due to glutathione depletion. A two-colour flow cytometry analysis of bethoxazin treated K562 cells for eight hours demonstrated that bethoxazin provokes necrosis induced cell death in K562 cells. Taken together, these experimental results demonstrate that the reaction of bethoxazin with proteins containing an accessible sulfhydryl group is more likely to be the mechanism of action of the cell growth inhibition effects rather than glutathione depletion.
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Gooch, Carolyn A. "Quantitative structure-activity relationships : a biophysical, chemical and calorimetric study." Thesis, Royal Holloway, University of London, 1988. http://repository.royalholloway.ac.uk/items/26719d55-b208-4995-bef0-92e4f0f80c0e/1/.

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Quantitative structure-activity relationships (QSAR) rationalize interrelation between molecular structure and biological response in terms of either physicochemical parameters, as in linear free energy relationships (LFER), or via purely empirical parameters, as is the case for De Novo schemes. In LFER the leading process is often the partitioning of a compound between two solvent phases, taken to represent the transfer of a drug molecule across a biological membrane. This study has investigated the partitioning behaviour of three series of hydroxybenzoate esters, viz. o-, m- and predominantly p-esters, the latter being preservatives in pharmaceutical formulations. The thermodynamic parameters AH, AG and AS for the transfer process were derived in an attempt to establish a QSAR. on a fundamental thermodynamic basis. Such parameters have identifiable physicochemical meaning and lend themselves more readily to interpretation. This facilitates application to alternative systems. A new Gibbs function factor analysis was developed and utilized to obtain thermodynamic contributions for parent and incremental methylene group portions of thestudy molecules. The empirical Collander equation for interrelation of various solute/solvent systems was also rationalized on a thermodynamic basis. Further extension of the Gibbs function factor analysis allowed scaling of "solvent" systems including chromatographic packings, solvents and liposomes. The scheme indicated capacity for optimized selection of bulk solvent systems to mimic biological membranes. A novel analytical procedure for direct measurement of biological response was developed. The bioassay appeared capable of discrimination i) between the closely related structural homologues, ii) between gram-negative and gram-positive bacteria, and further, iii) between certain cell batches of the same bacteria type. Also, the bioassay demonstrated a Collander interrelation between the two bacteria types. Flow microcalorimetry was the technique employed to measure thermal response of respiring E. coli and Staph, aur. bacteria. The modification of biological response with drug concentration was quantitated and a log dose max term was derived for each homologue. The results indicated potential for a predictive, additive structure-activity scheme based on assessment of biological response (BR) direct rather than through f(BR) via physicochemical or empirical parameters.
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Yang, Emma. "Chemical, metabolic and structure-activity relationships to probe abacavir toxicity." Thesis, University of Liverpool, 2014. http://livrepository.liverpool.ac.uk/2008286/.

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Adverse drug reactions (ADRs) are responsible for an increasing number of hospitalised patients, with the large majority of these ADRs classed as either type A or type B. Drug hypersensitivity reactions fall within the type B category and one such drug responsible for this form of ADR is abacavir (ABC). ABC, a nucleoside reverse transcriptase inhibitor, is used to treat the HIV-1 virus. It is responsible for a potentially life-threatening type IV hypersensitivity reaction which occurs in patients bearing the HLA-B*57:01 allele. Although many mechanisms have been proposed, it was the objective of this research to examine all these previous proposals to further extend and develop the mechanism of ABC toxicity. In Chapter 2, deuterated-ABC (D2-ABC) was designed and synthesised where the two 5'-H atoms were replaced with two 5'-D atoms. The design of this analogue was intended to retard the oxidative metabolism of ABC to its aldehyde and carboxylic acid metabolites. The synthesis of this compound was paramount to investigating this metabolism and through a series of metabolic experiments, described in Chapter 3, a kinetic isotope effect between ABC and D2-ABC was determined, ultimately showing an altered metabolism between the two compounds. To investigate binding of ABC within the HLA-B*57:01 protein, analogues of ABC, with alterations at varying positions within the molecule, were required. Using a racemic method, ABC enantiomers were synthesised and ABC’s enantiomer failed to stimulate T-cells in vitro. The creation of further analogues required the development of an asymmetric synthetic route. A total synthetic method was desired to synthesise intermediates to be used in future analogue synthesis. Finally, as described in Chapter 5, a range of 6-position analogues were designed, using a structure-activity relationship method, and synthesised, to further investigate the altered repertoire mechanism. These analogues, consisting of primary and secondary amine and oxy moieties, were subjected to in vitro immunological assays to determine their stimulation of T-cells. Additionally, the synthesised analogues were modelled in silico using molecular docking within the HLA protein. The in silico results assisted in explaining the basis of such T-cell activation/inactivation and will direct future analogue design. IC50 and EC50 values were determined for analogues that presented a negative T-cell response and a compound showing positive values was subjected to further pharmacokinetic testing. The oxidative metabolism of ABC was affected by isotopic substitution, but initial results have shown no altered T-cell stimulation of D2-ABC compared to ABC. This mechanism cannot be discarded, with further investigational work required. However, the synthesised 6-position analogues have assisted in further examining the altered repertoire mechanism and initial findings have enabled further understanding of the binding of ABC within HLA-B*57:01. This mechanism of ABC toxicity appears paramount to others proposed and the results presented in this thesis support this. Additional analogue synthesis and in vivo experiments will assist in confirming this further.
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Books on the topic "Chemical activity"

1

Susan, Hershberger, and Hogue, Lynn (Lynn M.), eds. Safe not sorry!: Chemical safety activity handbook. Middletown, Ohio: Terrific Science Press, 2007.

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Arya, D. P. Aminoglycoside antibiotics: From chemical biology to drug discovery. Hoboken, N.J: Wiley-Interscience, 2007.

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Patton, Craig Dean. Flammable material: German chemical workers in war, revolution, and inflation, 1914-1924. Berlin: Haude & Spener, 1998.

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Backlund, Peter. Mutagenic activity and chlorinated by-products in disinfected waters. Åbo: Åbo Academy Press, 1991.

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Goydan, Rosemary. Development of a data base on chemical migration from polymeric materials. Cincinnati, OH: U.S. Environmental Protection Agency, Risk Reduction Engineering Laboratory, 1990.

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Goydan, Rosemary. Development of a data base on chemical migration from polymeric materials. Cincinnati, OH: U.S. Environmental Protection Agency, Risk Reduction Engineering Laboratory, 1990.

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Navarro, Paula. Incredible experiments with chemical reactions and mixtures. Hauppage, New York: Barron's Educational Series, 2014.

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Meares, Patrick. Synthetic membranes and their applications: A survey of activity in the UK at April 1985 : a report. Swindon: Biotechnology Directorate, SERC, 1985.

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Despić, Aleksandar R. Serbian Chemical Society: History, organization, activity, 1897-1997 = Srpsko xemijsko društvo : istorija, ustrojstvo, delatnost, 1897-1997. Belgrade: Serbian Chemical Society, 1996.

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Despić, Aleksandar R. Serbian Chemical Society: History, organization, activity, 1897-1997 = Srpsko xemijsko društvo : istorija, ustrojstvo, delatnost, 1897-1997. Belgrade: Serbian Chemical Society, 1996.

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Book chapters on the topic "Chemical activity"

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Page, M. I. "Structure-activity relationships: chemical." In The Chemistry of β-Lactams, 79–100. Dordrecht: Springer Netherlands, 1992. http://dx.doi.org/10.1007/978-94-011-2928-2_2.

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Matsushita, Taishi, and Kusuhiro Mukai. "Chemical Potential and Activity." In Chemical Thermodynamics in Materials Science, 103–55. Singapore: Springer Singapore, 2018. http://dx.doi.org/10.1007/978-981-13-0405-7_8.

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Meyer, Ernst, and Ehrhard Sens. "Systematic Drug Structure-Activity Evaluation/Correlation." In Chemical Structures, 235–41. Berlin, Heidelberg: Springer Berlin Heidelberg, 1988. http://dx.doi.org/10.1007/978-3-642-73975-0_24.

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Nendza, Monika. "Assessments of chemical mixtures." In Structure—Activity Relationships in Environmental Sciences, 195–99. Boston, MA: Springer US, 1998. http://dx.doi.org/10.1007/978-1-4615-5805-7_8.

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Nendza, Monika. "Descriptors of the chemical structures." In Structure—Activity Relationships in Environmental Sciences, 15–46. Boston, MA: Springer US, 1998. http://dx.doi.org/10.1007/978-1-4615-5805-7_2.

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Urry, D. W. "Biomolecular Conformation and Biological Activity." In Advances in Chemical Physics, 581–600. Hoboken, NJ, USA: John Wiley & Sons, Inc., 2007. http://dx.doi.org/10.1002/9780470143698.ch40.

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Grilli, S., S. Bartoli, B. Bonora, A. Colacci, G. Lattanzi, M. Mazzullo, A. Niero, P. Perocco, and M. P. Turina. "Genotoxicity of Chloroethanes and Structure-Activity Relationships." In Chemical Carcinogenesis 2, 381–91. Boston, MA: Springer US, 1991. http://dx.doi.org/10.1007/978-1-4615-3694-9_38.

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Busse, Ewald W. "Neuropeptides and Chemical Messengers in the Aging Brain." In Biological Psychiatry, Higher Nervous Activity, 9–14. Boston, MA: Springer US, 1985. http://dx.doi.org/10.1007/978-1-4684-8329-1_2.

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Sigman, David S., and Chi-hong B. Chen. "Chemical Nuclease Activity of 1,10-Phenanthrolinecopper." In ACS Symposium Series, 24–47. Washington, DC: American Chemical Society, 1989. http://dx.doi.org/10.1021/bk-1989-0402.ch002.

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Burgot, Jean-Louis. "Chemical Equilibrium Between Gases and Statistical Thermodynamics." In The Notion of Activity in Chemistry, 399–405. Cham: Springer International Publishing, 2016. http://dx.doi.org/10.1007/978-3-319-46401-5_36.

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Conference papers on the topic "Chemical activity"

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Jobava, J. Sh, G. I. Kalandadze, and P. J. Kervalishvili. "Chemical activity of elementary boron." In Boron-rich solids. AIP, 1991. http://dx.doi.org/10.1063/1.40834.

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Grybaitė, Birutė, Rita Vaickelionienė, Vytautas Mickevičius, Viktor Zvarych, and Volodymyr Novikov. "Synthesis and antimicrobial activity of novel 2,4-disubstituted thiazoles." In Chemical technology and engineering. Lviv Polytechnic National University, 2019. http://dx.doi.org/10.23939/cte2019.01.249.

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Mettin, Robert, Andrea Thiemann, Carlos Cairós Barreto, Frank Holsteyns, and Adriano Troia. "Bubble Collapse Modality and Sono-Chemical Activity." In 8th International Symposium on Cavitation. Singapore: Research Publishing Services, 2012. http://dx.doi.org/10.3850/978-981-07-2826-7_127.

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Wain, Andrew J. "Advances in measurement of interfacial chemical activity." In 17th International Congress of Metrology, edited by Bernard Larquier. Les Ulis, France: EDP Sciences, 2015. http://dx.doi.org/10.1051/metrology/20150014006.

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Chandraker, Kumudini, and Manmohan L. i. Satnam. "Synthesis, Characterization and Antioxidant Activity of Thiol Functionalized Gold Nanoparticles." In Annual International Conference on Chemistry, Chemical Engineering and Chemical Process ( CCECP 2016 ). Global Science & Technology Forum ( GSTF ), 2016. http://dx.doi.org/10.5176/2301-3761_ccecp16.11.

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"Computer prediction of biological activity of 1,2,4-triazole derivatives of 1,4-naphthoquinone." In Chemical technology and engineering. Lviv Polytechnic National University, 2021. http://dx.doi.org/10.23939/cte2021.01.032.

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"Synthesis and antibiofilm activity of substituted 1-deazapyrimido[1,2,3-cd]purinium salts." In Chemical technology and engineering. Lviv Polytechnic National University, 2021. http://dx.doi.org/10.23939/cte2021.01.191.

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"Antioxidant Activity of some Amidine Derivatives." In International Conference on Chemical, Agricultural and Biological Sciences. Emirates Research Publishing, 2015. http://dx.doi.org/10.17758/erpub.er915010.

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"2D-Quantitative Structure Activity Study and the Computational Prediction of Antibacterial Activity for Series of Quinolones Derivatives." In International Conference on Chemical, Agricultural and Biological Sciences. Emirates Research Publishing, 2015. http://dx.doi.org/10.17758/erpub.er915027.

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Sicho, Martin, Daniel Svozil, and David Hoksza. "Activity-driven exploration of chemical space with morphing." In 2015 IEEE International Conference on Bioinformatics and Biomedicine (BIBM). IEEE, 2015. http://dx.doi.org/10.1109/bibm.2015.7359824.

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Reports on the topic "Chemical activity"

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Fox, K., and T. B. Edwards. Chemical composition measurements of the low activity waste (LAW) EPA-Series glasses. Office of Scientific and Technical Information (OSTI), March 2016. http://dx.doi.org/10.2172/1244072.

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Zimmerman, G. P., E. L. Hillsman, R. O. Johnson, R. L. Miller, T. G. Patton, G. M. Schoepfle, V. R. Tolbert, et al. Disposal of chemical agents and munitions stored at Umatilla Depot Activity, Hermiston, Oregon. Office of Scientific and Technical Information (OSTI), February 1993. http://dx.doi.org/10.2172/6470882.

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Wright, C. W., and D. D. Dauble. Effects of coal rank on the chemical composition and toxicological activity of coal liquefaction materials. Office of Scientific and Technical Information (OSTI), May 1986. http://dx.doi.org/10.2172/5759508.

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Herbst, A. K., D. W. Marshall, and J. A. McCray. Idaho Chemical Processing Plant low-activity waste grout stabilization development program FY-97 status report. Office of Scientific and Technical Information (OSTI), February 1998. http://dx.doi.org/10.2172/650159.

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Idakwo, Gabriel, Sundar Thangapandian, Joseph Luttrell, Zhaoxian Zhou, Chaoyang Zhang, and Ping Gong. Deep learning-based structure-activity relationship modeling for multi-category toxicity classification : a case study of 10K Tox21 chemicals with high-throughput cell-based androgen receptor bioassay data. Engineer Research and Development Center (U.S.), July 2021. http://dx.doi.org/10.21079/11681/41302.

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Deep learning (DL) has attracted the attention of computational toxicologists as it offers a potentially greater power for in silico predictive toxicology than existing shallow learning algorithms. However, contradicting reports have been documented. To further explore the advantages of DL over shallow learning, we conducted this case study using two cell-based androgen receptor (AR) activity datasets with 10K chemicals generated from the Tox21 program. A nested double-loop cross-validation approach was adopted along with a stratified sampling strategy for partitioning chemicals of multiple AR activity classes (i.e., agonist, antagonist, inactive, and inconclusive) at the same distribution rates amongst the training, validation and test subsets. Deep neural networks (DNN) and random forest (RF), representing deep and shallow learning algorithms, respectively, were chosen to carry out structure-activity relationship-based chemical toxicity prediction. Results suggest that DNN significantly outperformed RF (p < 0.001, ANOVA) by 22–27% for four metrics (precision, recall, F-measure, and AUPRC) and by 11% for another (AUROC). Further in-depth analyses of chemical scaffolding shed insights on structural alerts for AR agonists/antagonists and inactive/inconclusive compounds, which may aid in future drug discovery and improvement of toxicity prediction modeling.
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Marks, Marguerite. Incorporating Chemical Activity and Relative Humidity Effects in Regional Air Quality Modeling of Organic Aerosol Formation. Portland State University Library, January 2000. http://dx.doi.org/10.15760/etd.1509.

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Terry, J. W., T. J. Blasing, J. T. Ensminger, R. O. Johnson, S. M. Schexnayder, J. T. Shor, W. P. Staub, V. R. Tolbert, and G. P. Zimmerman. Disposal of chemical agents and munitions stored at Pueblo Depot Activity, Colorado. Final, Phase 1: Environmental report. Office of Scientific and Technical Information (OSTI), April 1995. http://dx.doi.org/10.2172/109661.

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Zimmerman, G. P., E. L. Hillsman, R. O. Johnson, R. L. Miller, T. G. Patton, G. M. Schoepfle, V. R. Tolbert, et al. Disposal of chemical agents and munitions stored at Umatilla Depot Activity, Hermiston, Oregon. Final Phase 1 environmental report. Office of Scientific and Technical Information (OSTI), February 1993. http://dx.doi.org/10.2172/10155526.

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Karabörklü, Salih, Urgur Azizoglu, Semih Yilmaz, Abdurrahman Ayvaz, and Mehmet Akdeniz. The Chemical Composition of Cyclotrichium origanifolium Essential Oil and Its Insecticidal Activity against Four Stored-product Insect Pests. "Prof. Marin Drinov" Publishing House of Bulgarian Academy of Sciences, June 2019. http://dx.doi.org/10.7546/crabs.2019.06.18.

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Olshansky, S. J., J. R. Krummel, A. J. Policastro, and L. D. McGinnis. Chemical Stockpile Disposal Program: Review and comment on the Phase 1 environmental report for the Pueblo Depot Activity, Pueblo, Colorado. Office of Scientific and Technical Information (OSTI), March 1994. http://dx.doi.org/10.2172/10151220.

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