Academic literature on the topic 'Seco acids'
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Journal articles on the topic "Seco acids"
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Szoka, Łukasz, Valery Isidorov, Jolanta Nazaruk, Marcin Stocki, and Leszek Siergiejczyk. "Cytotoxicity of Triterpene Seco-Acids from Betula pubescens Buds." Molecules 24, no. 22 (November 9, 2019): 4060. http://dx.doi.org/10.3390/molecules24224060.
Full textAbstract:
The present study investigated the magnitude and mechanism of the cytotoxic effect on selected cancer cell lines of 3,4-seco-urs-4(23),20(30)-dien-3-oic acid (1), 3,4-seco-olean-4(24)-en-19-oxo-3-oic acid (2), and 3,4-seco-urs-4(23),20(30)-dien-19-ol-3-oic acid (3) isolated from downy birch (Betula pubescens) buds by carbon dioxide supercritical fluid extraction and gradient column chromatography. Cell viability in six human cancer lines exposed to these compounds was determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Apoptosis was quantified by annexin V/propidium iodide staining of gastric cancer AGS and colorectal cancer DLD-1 cells. To evaluate the mechanism of apoptosis, the expression of apoptosis-related proteins was analyzed by Western blot. Compound 1 exhibited non-specific toxicity, while compounds 2 and 3 were specifically toxic to colon and stomach cancer cells. The toxicity of compounds 2 and 3 against these two cell lines was greater than for compound 1. Cleavage of caspase-8, -9, and -3 was found in AGS and DLD-1 cells treated with all three seco-acids, indicating the induction of apoptosis via extrinsic and intrinsic pathways. Therefore, triterpene seco-acids (1–3) decreased cell viability by apoptosis induction. AGS and DLD-1 cells were more susceptible to seco-acids with an oxidized C19 than normal fibroblasts. Hence, it made them a new group of triterpenes with potential anticancer activity.
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Ma, Bin, Yan-Ping Shi, and Zhong-Jian Jia. "A-seco-Oleane-Type Triterpene Acids fromLigularia intermedia." Planta Medica 63, no. 06 (December 1997): 573–74. http://dx.doi.org/10.1055/s-2006-957773.
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de Léséleuc, Mylène, and Shawn K. Collins. "Direct Macrolactonization of Seco Acids via Hafnium(IV) Catalysis." ACS Catalysis 5, no. 3 (February 2, 2015): 1462–67. http://dx.doi.org/10.1021/acscatal.5b00082.
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Katoh, Tadashi, Noel Sayar, and Koichi Narita. "Facile Total Synthesis of Thailandepsins D–F: Novel Bicyclic Depsipeptide Histone Deacetylase Inhibitors Isolated from a Microorganism." Synthesis 51, no. 06 (February 1, 2019): 1419–26. http://dx.doi.org/10.1055/s-0037-1611707.
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The naturally occurring bicyclic depsipeptide histone deacetylase inhibitors thailandepsins D–F were efficiently synthesized for the first time in 49–61% overall yield over five steps, starting from known amine and carboxylic acid segments. The synthesis includes the condensation of the two known starting materials to directly assemble the corresponding seco-acids, which are the key precursors for macrolactonization. The seco-acids are then macrolactonized using the Shiina method to construct the requisite 15-member macrocycles.
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Ainge, Simon W., and Pierre Vogel. "Total asymmetric synthesis of seco-acids of 9,12-anhydroerythronolide aglycons." Tetrahedron Letters 39, no. 23 (June 1998): 4039–42. http://dx.doi.org/10.1016/s0040-4039(98)00691-1.
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ZORINA, A. D., YU D. MIKHAILOV, L. V. BALYKINA, I. I. SMIRNOV, V. G. PLATONOV, M. A. GORDON, N. P. CHIZHOV, and A. G. SHAVVA. "ChemInform Abstract: Synthesis of Seco-Acids of the Dammarane Series." ChemInform 28, no. 46 (August 3, 2010): no. http://dx.doi.org/10.1002/chin.199746193.
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Parsons, Ian C., Alexander I. Gray, Peter G. Waterman, Catherine Lavaud, and Georges Massiot. "Seco ring-A triterpene acids from the resin of Dacryodes normandii." Phytochemistry 30, no. 4 (January 1991): 1221–23. http://dx.doi.org/10.1016/s0031-9422(00)95205-1.
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Patel, Dinesh V., and Eric M. Gordon. "C-2 desmethyl seco-mevinic acids. Monocyclic HMG-CoA reductase inbibitors." Bioorganic & Medicinal Chemistry Letters 1, no. 10 (January 1991): 509–12. http://dx.doi.org/10.1016/s0960-894x(01)80455-8.
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Klinotová, Eva, Helena Pavlíková, Martina Pressová, Hana Chodounská, Jiří Klinot, Jiří Protiva, and Alois Vystrčil. "E-seco-Acids of pentacyclic triterpenoids. Oxidative cleavage of ring E in 3β-acetoxy-21-oxo-18α,19βH-ursan-28→20β-olide." Collection of Czechoslovak Chemical Communications 52, no. 11 (1987): 2744–52. http://dx.doi.org/10.1135/cccc19872744.
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Oxidative cleavage of 3β-acetoxy-22-hydroxymethylene-21-oxo-18α,19βH-ursan-28→20β-olide (VII) and 3β-acetoxy-21,22-dioxo-18α,19βH-ursan-28→20β-olide (VIII) afforded primarily the E-seco-acid XII which was converted into acids XVI and XX, isomeric at the C(17) carbon atom. Configuration of these acids has been determined.
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AINGE, S. W., and P. VOGEL. "ChemInform Abstract: Total Asymmetric Synthesis of seco-Acids of 9,12-Anhydroerythronolide Aglycons." ChemInform 29, no. 34 (June 20, 2010): no. http://dx.doi.org/10.1002/chin.199834282.
Full textDissertations / Theses on the topic "Seco acids"
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Burgess, Vanessa Anne, and n/a. "Toxicology Investigations With The Pectenotoxin-2 Seco Acids." Griffith University. School of Public Health, 2003. http://www4.gu.edu.au:8080/adt-root/public/adt-QGU20030905.090222.
Full textAbstract:
Pectenotoxins (PTXs) are a group of large cyclic polyether compounds associated with diarrhetic shellfish poisoning (DSP) as they are often found in combination with other DSPs such as okadaic acid (OA) and dinophysis toxins (DTXs) in shellfish. Although classified and regulated with the DSPs, there is debate over whether these toxins should be classified with DSP toxins. To date, ten different analogues of PTXs have been identified from shellfish and algae, and of these, the pectenotoxin-2 seco acids (PTX2-SAs) are of particular interest as they have previously been implicated in a shellfish poisoning incident in Australia, but relatively little was known of their toxicology. One such incident occurred in December 1997, when approximately 200 people were reported with severe diarrhoetic shellfish poisoning in Northern New South Wales (NSW). Analysis of the shellfish associated with this incident revealed relatively high PTX2-SA concentrations (approx. 300 micrograms/kg shellfish meat), with only trace amounts of pectenotoxin-2 (PTX2) and OA. Following this incident, PTX2-SAs were considered a health threat and guidelines were implemented in the absence of toxicological data, which has caused a great economic burden to shellfish industries around the globe, in particular to Australia, New Zealand and Ireland. Such regulation created in the absence of scientific data demonstrated the need to determine the toxicology of PTX2-SAs in commercial shellfish. Thus a comprehensive study on the toxicology and possible health implications of the PTX2-SAs in Australian shellfish was conducted. PTX2-SAs were isolated in different batches from shellfish (pipis, oysters and mussels) and from algal bloom samples of Dinophysis caudata. Toxin extraction was conducted with several purification stages and chemical analysis was performed with high-performance liquid chromatography coupled to a tandem mass spectrometer (HPLC-MS/MS). The chemical stability of the PTX2-SAs was investigated to ensure consistency of doses between toxicology experiments. Acute dosing studies with mice were then performed and included toxicopathology investigations with light microscopy and electron microscopy, in addition to toxin distribution studies and investigation of in vivo lipid peroxidation. In vitro studies with HepG2 cells included cytotoxicity assays, cell cycle investigations using flow cytometry and gene expression profiling of cells exposed to PTX2-SAs employing cDNA microarray technology. Acute pathology studies demonstrated that the PTX2-SAs do not cause the characteristic symptoms or lesions associated with DSP toxins. No diarrhoea was observed at any dose level in mice and no deaths occurred up to the maximum dosing level of 1.6mg/kg PTX2-SA. Only one batch of PTX2-SA extract produced toxic lesions characteristic of a DSP toxin (batch 1-pilot study) but after follow up studies, it was determined that this first batch of shellfish most likely contained an additional unidentified shellfish toxin or contaminant that co-extracted with PTX2-SAs during toxin isolation and purification procedures. This finding highlighted the importance of supporting the inclusion of the mice bioassay in procedures for shellfish toxin testing to enable detection of new toxins, and also highlighted the importance of toxin purification for toxicology studies. A significant rise in malondialdehyde excretion was observed within 24 hours of dosing mice, indicating that the PTX2-SAs may cause damage by lipid peroxidation in vivo. In vitro studies showed HepG2 cells to have cell cycle and gene expression changes within 24 hours of a dose of 800ng/mL PTX2-SAs. Cell cycle arrest was observed at the G2/M checkpoint and gene expression changes included alterations in genes involved in cell cycle control, lipid metabolism and transport, lipid genesis and trace metal transport. Many genes involved in DNA repair processes were moderated at the 24 hour point, but as no apoptosis was observed up to 72 hours post dosing it is a promising indication that any DNA damage that may have been caused by the administration of PTX2-SAs was not lethal, and was able to be repaired. In light of the information provided by toxicology investigations in this PhD, with particular reference to evidence of in vivo lipid peroxidation by raised levels of MDA in mouse urine, and changes in cell cycle distribution and gene expression in a cultured human cell line, it is concluded that there is potential for these toxins to induce biological changes in mammalian cells in vivo and in vitro, and hence potential for PTX2-SAs to cause health effects in humans. During the course of this three-year study, developments in techniques for shellfish toxin identification within our laboratories have revealed that the shellfish responsible for the 1997 NSW poisoning incident contained significant concentrations of okadaic acid acyl esters that were not detected at the time of the NSW incident. Although reportedly less toxic than okadaic acid itself, the OA ester concentrations present may have been sufficient to cause the observed symptoms. It is also theorized that these esters could be hydrolyzed in the human gastro-intestinal tract to release okadaic acid. In the light of this new evidence and with no pathology lesions or symptoms of diarrhoea being observed in PTX2-SA dosing studies with mice, we now believe these OA acyl esters to be the causative agent in the 1997 NSW DSP incident and not the PTX2-SAs. Nothing is currently known of the chronic toxicology of PTX2-SAs and thus their potential implications to public health in the long term cannot determined. The toxicology investigations in this thesis were acute studies, and it has not been established if the observed changes could be repaired or returned within normal limits without the manifestation of illness or disease occurring. Utilizing the acute toxicology information in this thesis, a health risk assessment for consumption of PTX2-SA contaminated shellfish was performed. This risk assessment, employing numerous safety factors essential for an incomplete data set, produced guideline values that are lower than the current recommend concentrations. To date, there has been no solid evidence that PTX2-SAs cause illness in humans all documented incidents involving the PTX2-SAs have also included other DSP contaminants that are known to cause human illness. Pathology has not unequivocally been demonstrated in animal studies and thus, in consideration of the epidemiological evidence, PTX2-SAs cannot be considered as high a risk to public health as was previously thought. For the reasons discussed above, and weighing up risk-benefit considerations of the economic burden the current guideline values are causing to shellfish industries around the globe, it is recommended that levels of PTX2-SAs be monitored in recognition of the precautionary principle, but no longer regulated as tightly with other DSPs until such a time that toxicological or epidemiological evidence can prove that the PTX2-SAs are a DSP and are a more considerable threat to human health than has been indicated by toxicology studies in this thesis. This study has produced a substantial amount of acute toxicology data and has provided a good basis for future chronic toxicology investigations with the PTX2-SAs for regulatory purposes.
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Burgess, Vanessa Anne. "Toxicology Investigations With The Pectenotoxin-2 Seco Acids." Thesis, Griffith University, 2003. http://hdl.handle.net/10072/365382.
Full textAbstract:
Pectenotoxins (PTXs) are a group of large cyclic polyether compounds associated with diarrhetic shellfish poisoning (DSP) as they are often found in combination with other DSPs such as okadaic acid (OA) and dinophysis toxins (DTXs) in shellfish. Although classified and regulated with the DSPs, there is debate over whether these toxins should be classified with DSP toxins. To date, ten different analogues of PTXs have been identified from shellfish and algae, and of these, the pectenotoxin-2 seco acids (PTX2-SAs) are of particular interest as they have previously been implicated in a shellfish poisoning incident in Australia, but relatively little was known of their toxicology. One such incident occurred in December 1997, when approximately 200 people were reported with severe diarrhoetic shellfish poisoning in Northern New South Wales (NSW). Analysis of the shellfish associated with this incident revealed relatively high PTX2-SA concentrations (approx. 300 micrograms/kg shellfish meat), with only trace amounts of pectenotoxin-2 (PTX2) and OA. Following this incident, PTX2-SAs were considered a health threat and guidelines were implemented in the absence of toxicological data, which has caused a great economic burden to shellfish industries around the globe, in particular to Australia, New Zealand and Ireland. Such regulation created in the absence of scientific data demonstrated the need to determine the toxicology of PTX2-SAs in commercial shellfish. Thus a comprehensive study on the toxicology and possible health implications of the PTX2-SAs in Australian shellfish was conducted. PTX2-SAs were isolated in different batches from shellfish (pipis, oysters and mussels) and from algal bloom samples of Dinophysis caudata. Toxin extraction was conducted with several purification stages and chemical analysis was performed with high-performance liquid chromatography coupled to a tandem mass spectrometer (HPLC-MS/MS). The chemical stability of the PTX2-SAs was investigated to ensure consistency of doses between toxicology experiments. Acute dosing studies with mice were then performed and included toxicopathology investigations with light microscopy and electron microscopy, in addition to toxin distribution studies and investigation of in vivo lipid peroxidation. In vitro studies with HepG2 cells included cytotoxicity assays, cell cycle investigations using flow cytometry and gene expression profiling of cells exposed to PTX2-SAs employing cDNA microarray technology. Acute pathology studies demonstrated that the PTX2-SAs do not cause the characteristic symptoms or lesions associated with DSP toxins. No diarrhoea was observed at any dose level in mice and no deaths occurred up to the maximum dosing level of 1.6mg/kg PTX2-SA. Only one batch of PTX2-SA extract produced toxic lesions characteristic of a DSP toxin (batch 1-pilot study) but after follow up studies, it was determined that this first batch of shellfish most likely contained an additional unidentified shellfish toxin or contaminant that co-extracted with PTX2-SAs during toxin isolation and purification procedures. This finding highlighted the importance of supporting the inclusion of the mice bioassay in procedures for shellfish toxin testing to enable detection of new toxins, and also highlighted the importance of toxin purification for toxicology studies. A significant rise in malondialdehyde excretion was observed within 24 hours of dosing mice, indicating that the PTX2-SAs may cause damage by lipid peroxidation in vivo. In vitro studies showed HepG2 cells to have cell cycle and gene expression changes within 24 hours of a dose of 800ng/mL PTX2-SAs. Cell cycle arrest was observed at the G2/M checkpoint and gene expression changes included alterations in genes involved in cell cycle control, lipid metabolism and transport, lipid genesis and trace metal transport. Many genes involved in DNA repair processes were moderated at the 24 hour point, but as no apoptosis was observed up to 72 hours post dosing it is a promising indication that any DNA damage that may have been caused by the administration of PTX2-SAs was not lethal, and was able to be repaired. In light of the information provided by toxicology investigations in this PhD, with particular reference to evidence of in vivo lipid peroxidation by raised levels of MDA in mouse urine, and changes in cell cycle distribution and gene expression in a cultured human cell line, it is concluded that there is potential for these toxins to induce biological changes in mammalian cells in vivo and in vitro, and hence potential for PTX2-SAs to cause health effects in humans. During the course of this three-year study, developments in techniques for shellfish toxin identification within our laboratories have revealed that the shellfish responsible for the 1997 NSW poisoning incident contained significant concentrations of okadaic acid acyl esters that were not detected at the time of the NSW incident. Although reportedly less toxic than okadaic acid itself, the OA ester concentrations present may have been sufficient to cause the observed symptoms. It is also theorized that these esters could be hydrolyzed in the human gastro-intestinal tract to release okadaic acid. In the light of this new evidence and with no pathology lesions or symptoms of diarrhoea being observed in PTX2-SA dosing studies with mice, we now believe these OA acyl esters to be the causative agent in the 1997 NSW DSP incident and not the PTX2-SAs. Nothing is currently known of the chronic toxicology of PTX2-SAs and thus their potential implications to public health in the long term cannot determined. The toxicology investigations in this thesis were acute studies, and it has not been established if the observed changes could be repaired or returned within normal limits without the manifestation of illness or disease occurring. Utilizing the acute toxicology information in this thesis, a health risk assessment for consumption of PTX2-SA contaminated shellfish was performed. This risk assessment, employing numerous safety factors essential for an incomplete data set, produced guideline values that are lower than the current recommend concentrations. To date, there has been no solid evidence that PTX2-SAs cause illness in humans – all documented incidents involving the PTX2-SAs have also included other DSP contaminants that are known to cause human illness. Pathology has not unequivocally been demonstrated in animal studies and thus, in consideration of the epidemiological evidence, PTX2-SAs cannot be considered as high a risk to public health as was previously thought. For the reasons discussed above, and weighing up risk-benefit considerations of the economic burden the current guideline values are causing to shellfish industries around the globe, it is recommended that levels of PTX2-SAs be monitored in recognition of the precautionary principle, but no longer regulated as tightly with other DSPs until such a time that toxicological or epidemiological evidence can prove that the PTX2-SAs are a DSP and are a more considerable threat to human health than has been indicated by toxicology studies in this thesis. This study has produced a substantial amount of acute toxicology data and has provided a good basis for future chronic toxicology investigations with the PTX2-SAs for regulatory purposes.Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
School of Public Health
Faculty of Health Sciences
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Sampaio, Geni Rodrigues. "Ocorrência de óxidos de colesterol e análise do perfil lipídico em camarão salgado-seco." Universidade de São Paulo, 2004. http://www.teses.usp.br/teses/disponiveis/89/89131/tde-16102006-141648/.
Full textAbstract:
Alimentos submetidos a processos tecnológicos que requerem altas temperaturas apresentam um grande potencial para a produção de óxidos de colesterol (OsC). Inúmeras evidências indicaram que os óxidos de colesterol são potencialmente citotóxicos, aterogênicos, mutagênicos e carcinogênicos. Em pescados, a oxidação do colesterol está favorecida pela presença de ácidos graxos poliinsaturados e altos níveis de colesterol. O camarão salgado-seco é particularmente suscetível à formação de óxidos de colesterol devido a sua composição lipídica, ao seu processamento e as condições de estocagem. O objetivo deste trabalho foi determinar a ocorrência de produtos da oxidação do colesterol e analisar o perfil lipídico em camarão salgado-seco. Analisou-se cinqüenta amostras de camarão salgado-seco por cromatografia líquida de alta eficiência (HPLC), através da qual foram determinados os teores de óxidos de colesterol. O colesterol e os óxidos de colesterol (7ß-OH, 7?-OH, 7-Ceto e 25-OH) foram analisados simultaneamente. O perfil de ácidos graxos foi determinado por cromatografia gasosa e para a avaliação da oxidação lipídica foi empregado o teste de TBARS. Os resultados indicaram que as amostras examinadas continham: 7ß-OH (34,63-72,56 µg/g), 7?-OH (5,02-12,12 µg/g), 7-Ceto (7,44-32,68 µg/g) e 25-OH (2,37-22,88 µg/g), sendo o 7ß-OH o óxido predominante. A quantidade de (OsC) nas amostras analisadas variou consideravelmente (4,52 a 77,30 µg/g). Quanto ao teor de colesterol total e a concentração média de TBARS, os resultados variaram de 73,88 a 247,69 mg/100g e 0,023 a 1,30 mgMA/Kg respectivamente. O perfil de ácidos graxos encontrado foi de 27,48 % saturados, 43,90% monoiinsaturados e 28,61% poliinsaturados. Este estudo indicou que as amostras estavam oxidadas, tanto pela presença de produtos da oxidação do colesterol como pelos valores de TBARS. Tal oxidação foi, provavelmente, iniciada no processamento e em condições inadequadas de armazenamento. Os resultados reforçaram a importância da reavaliação dos procedimentos que envolvem o manuseio de pescados, particularmente do camarão salgado-seco, desde a captura até a determinação do tempo de prateleira, no sentido de minimizar as reações oxidativas.Foods submitted to technological processes that require high temperature present a great potential for production of cholesterol oxides (COPs). Several evidences have indicated that COPs are potentially cytotoxic, atherogenic, mutagenic, and carcinogenic. In sea food, the cholesterol oxidation is favored by the presence of unsaturated fatty acids and high cholesterol levels. The salted-dried shrimp is particularly susceptible to the formation of COPs due to its lipidic composition, the processing and storage conditions. The objective of this work was to determine the occurrence of cholesterol oxidation products and to analyze the lipidic profile in salted-dried shrimp. Fifty samples of salted-dried shrimp were evaluated, and the cholesterol oxides were quantified by high-performance liquid chromatography (HPLC). Cholesterol and COPs (7ß-hydroxycholesterol, 7?- hydroxycholesterol, 7-Ketocholesterol and 25- hydroxycholesterol) were simultaneously analyzed. The fatty acids profile was determined by gas chromatography, and for the evaluation of lipidic oxidation the TBARS method was used. The results indicated that the samples contained: 7ß-OH (34.63-72,56 µg/g), 7?-OH (5.02-12.12µg/g), 7-Keto (7.44-32.68 µg/g) and 25-OH (2.37-22.88 µg/g). These data indicated that 7?-OH was the predominant product. The amount of COPs in the samples varied considerably, ranging from 4.52 to 77.30 µg/g. Regarding to the total cholesterol content and the average concentration of TBARS, the results varied from 73.88 to 247.69 mg/100g, and 0.023 to 1.30 mgMA/Kg, respectively. The fatty acids profile was: 27.48% saturated, 43.90% monounsaturated and 28.61% polyunsaturated. This study indicated that the samples were oxidized, by the presence of COPs and the values of TBARS as well. Such oxidation was probably initiated under inadequate conditions of processing and storage. These results reinforced the need of revaluation of the fishing handling procedures, particularly the salted-dried shrimp, including all the stages - from the capture to the de shelf-life determination, in order to minimize the oxidative reactions.
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Putrino, Soraia Marques. "Composição corporal, exigências de energia e proteína para ganho e composição da carne de novilhos Nelore alimentados com dietas com milho grão seco ou úmido contendo gordura não degradável no rúmen." Universidade de São Paulo, 2006. http://www.teses.usp.br/teses/disponiveis/74/74131/tde-11052006-135306/.
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A pecuária de corte no Brasil evoluiu muito em produtividade e qualidade do produto final, determinantes para a manutenção da atividade. A pesquisa no setor pecuário visa incrementar o lucro ao pecuarista, auxiliar na melhora das carcaças para o frigorífico e garantir carne de qualidade ao consumidor. A raça Nelore, amplamente difundida pelo país, sofre com o manejo nutricional deficiente, que prejudica o desempenho produtivo. O grão de milho é muito utilizado como fonte energética para os bovinos e estudos buscam melhorar o aproveitamento do amido do grão, como o fornecimento de grãos processados como milho úmido. Outra fonte energética para a suplementação de bovinos seria a gordura protegida da degradação ruminal. Neste experimento objetivou-se ampliar o conhecimento dos efeitos de alimentos energéticos (dietas contendo grão de milho seco ou úmido com ou sem gordura protegida da degradação ruminal) sobre a digestibilidade total, composição corporal e da carne de novilhos da raça Nelore. Não houve efeito dos tratamentos sobre os coeficientes de digestibilidade ou para a porcentagem de nutrientes digestíveis totais. Os tratamentos também não alteraram a composição corporal e as exigências líquidas de energia e proteína para ganho de peso. A inclusão de gordura à dieta reduziu a porcentagem de água e elevou o extrato etéreo da carne. Quanto ao perfil de ácidos graxos, o milho úmido aumentou os poliinsaturados, e a inclusão da gordura os ômega 6. Os cortes cárneos diferiram tanto na composição química quanto no perfil de ácidos graxos.The beef cattle in Brazil have been a great development on productivity and quality of end product. These are decisive for the maintenance of the activity. Researchs about cattle look for to increase the profit to the farmer, improve the quality of carcasses for slaughtered and to guarantee quality meat to consumer. Nelore breed, the mostly cattle of Brazilian herd, suffers with deficient nutricional handling that reduce the performance of animals.The corn grain is very used as energy source for catlle and researchs look for to improve the digestibility of starch of grain, as the supply of processed grains as high moisture corn grain. Another energy source for feed cattle is ruminal protected fat. In this study looks for increased the knowledge of effects of energetic foods (diets containing dry or high moisture corn grain with or without ruminal protected fat) on total digestibility, body composition and meat composition of Nellore breed steers. There was no effect of diets on digestibility coefficients or The percentage total digestible nutrients. Diets didn't also change the body composition and net requirements of energy and protein for weight gain. The addition of fat reduced the percentage of water and increased ether extract in the meat. About the fatty acids profile, high moisture corn grain increased polyunsaturated, and fat increased omega 6. Meat cuts differed in chemical composition and fatty acids profile.
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Coster, Mark Jeffrey. "Total synthesis of the protected seco-acid of spongistatin 1." Thesis, University of Cambridge, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.621217.
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Di, Francesco Maria Emilia. "Total synthesis of a fully protected Seco-acid of peloruside A." Thesis, University of Cambridge, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.616231.
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Bettero, Vitor Pereira [UNESP]. "Fontes de ácidos graxos insaturados na alimentação de vacas leiteiras no período seco." Universidade Estadual Paulista (UNESP), 2015. http://hdl.handle.net/11449/124015.
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000833950.pdf: 899007 bytes, checksum: ef68af17b4ad064adaad5d58e971c18c (MD5)O objetivo do trabalho foi avaliar os efeitos de fontes de ácidos graxos insaturados para vacas leiteiras no período seco sobre a dinâmica e bio-hidrogenação ruminais e fluxo intestinal de ácidos graxos. Foram utilizadas 8 vacas secas da raça Holandesa, canuladas no rúmen e abomaso (614 ± 59 kg de peso corporal; média ± dp), agrupadas em dois quadrados latinos 4 x 4 contemporâneos e balanceados, alimentadas com as seguintes dietas: 1) controle (C), dieta a base de milho e farelo de soja; 2) óleo de soja refinado (OS) com inclusão de 3,0% na MS total; 3) Grão de soja cru e integral (GS), com inclusão de 16,0% na MS total; e 4) Sais de cálcio de ácidos graxos insaturados (SC), com inclusão de 3,2% na MS total. Os consumos de MS, MO, PB, FDN e NDT não diferiram (P>0,05) entre tratamentos. Dietas com fontes lipídicas tiveram maior consumo de EE (0,72 vs 0,30 kg/dia) e menor consumo de CNF (3,91 vs 4,40 kg/dia) quando comparadas ao controle. As digestibilidades da MS, MO E FDN foram maiores (P<0,05) no tratamento controle em relação aos tratamentos com adição lipídica. Já em relação ao EE, a digestibilidade da dieta C foi menor (P<0,001) que nos demais tratamentos (84,88% vs 86,93%) . A concentração de N-NH3 foi maior (P<0,05) para os animais que receberam a dieta C em relação às dietas com inclusão de lipídios (20,39 vs 17,49 mg/dL). A dieta C apresentou as menores concentrações de propionato (P=0,001) em relação às fontes lipídicas. Já a dieta OS apresentou maiores concentrações de propionato (P<0,05) em relação às dietas GS e SC. A relação acetato:propionato (C2/C3) foi maior (P<0,05) na dieta controle (4,13) do que nas dietas com suplementação (3,81). A síntese de proteína microbiana e os balanços de energia e nitrogênio não foram influenciados pelas dietas experimentais. Animais que receberam dietas com suplementação lipídica apresentaram maiores valores de colesterol total e ...
The objective of this study was to evaluate the effects of sources of unsaturated fatty acids to dairy cows in the dry period on the ruminal dynamic and biohydrogenation and intestinal flow of fatty acids. Eight Holstein dry cows cannulated in the rumen and abomasum (614 ± 59 kg of body weight; mean ± SD), were assigned randomly in two contemporary and balanced 4 x 4 Latin squares, fed the following diets: 1) control (C) diet based on corn and soybean meal; 2) refined soybean oil (SO) with addition of 3.0% on total DM 3) Whole soybean raw (WS), with the inclusion of 16.0% on total DM; and 4) calcium salts of unsaturated fatty acids (CS), with the inclusion of 3.2% on total DM. The DM, OM, CP, NDF and TDN intakes did not differ (P> 0.05) between treatments. Diets with fat sources had higher intake of EE (0.72 vs 0.30 kg/day) and lower intake of NFC (3.91 vs 4.40 kg/day) when compared to control. The digestibilities of DM, OM and NDF were higher (P <0.05) in treatment C compared to treatments with lipid addition. In relation to EE, the digestibility of C diet was lower than in other treatments (84.88% vs 86.93%). The concentration of NH3-N was higher (P <0.05) in animals fed C diet than the diets with lipids inclusion (20.39 vs. 17.49 mg/dL). The C diet had the lowest propionate concentration in relation to lipid sources. The SO diet had higher propionate concentrations (P <0.05) compared to WS and CS diets. The acetate: propionate ratio (C2/C3) was higher (P <0.05) in the control diet (4.13) than the diets with supplementation (3.81). The microbial protein synthesis and energy and nitrogen balances were not affected by diets. Animals fed diets with fat supplements had higher total cholesterol and HDL cholesterol in the blood (P <0.05). The SO diet had lower ruminal digestion rates (P <0.05) for DM, NDF and pdNDF compared to WS and CS. WS diet had lower passage rates of DM, NDF and pdNDF (P <0.05) in relation to CS diet ...
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Connaulte, Julie. "Contribution de substances endogènes et exogènes au pouvoir antioxydant et antiradicalaire de fruits secs." Aix-Marseille 3, 1999. http://www.theses.fr/1999AIX30049.
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Un interet croissant est porte sur le role antioxydant de divers microconstituants presents dans les fruits et leurs produits derives, tels les polyphenols et les carotenoides. Le pouvoir antioxydant et antiradicalaire de fruits secs (pruneaux, abricots et raisins) a ete evalue et compare vis a vis de trois types de radicaux generes chimiquement : des radicaux peroxyles issus de la decomposition thermique du dihydrochlorate de 2,2 azobis amidinopropane, des radicaux hydroxyles les generes au cours de la reaction de fenton, et ceux issus du 1,1 diphenyl-2-picrylhydrazyl (dpph*). Les composes antioxydants ont ete extraits en utilisant des solvants de differente polarite. Ils ont ete caracterises et leurs structures correspondent a des composes phenoliques (derives benzoiques, esters hydroxycinnamiques, flavan-3-ols et flavonols), mais aussi a l'acide ascorbique (vitamine c), a des carotenoides et des glucides. Des dosages globaux ont permis d'evaluer leurs teneurs dans les differents fruits secs. Par ailleurs, les composes exogenes, l'acide sorbique et l'anhydride sulfureux, susceptibles d'interferer dans l'evaluation du pouvoir antioxydant, ont egalement ete determines. Le pouvoir antioxydant vis a vis des radicaux peroxyles et dpph* est correle a la teneur en composes phenoliques ; celui vis a vis des radicaux hydroxyles semble apparait etroitement lie a la composition en glucides. Les pouvoirs antioxydant et antiradicalaire de solutions modeles synthetiques preparees a partir de molecules commerciales ou isolees ont ete evalues. A l'aide de plans d'experimentation, des effets de synergisme antioxydant ont ete mis en evidence principalement entre la (+)-catechine et la procyanidine b 3 mais aussi entre la rutine et l'acide ascorbique, la rutine et la (+)-catechine, et entre la rutine et l'acide chlorogenique. Les mecanismes reactionnels impliques dans ces effets de synergisme sont discutes.
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Pereira, Antonio Marcelo. "Ar seco e aquecido no processo de dormência e germinação de sementes de Brachiaria humidicola." Universidade do Oeste Paulista, 2012. http://bdtd.unoeste.br:8080/tede/handle/tede/421.
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Antonio Marcelo Pereira.pdf: 349288 bytes, checksum: 6b2f395df14ed97262b2fc0a8c2f9b2d (MD5)
Previous issue date: 2012-09-27Sulfuric acid use has shown effectiveness in overcoming dormancy, even though its effective use carry some risks to the workers and environment. The work was carried out to study the sulfuric acid treatment effectiveness, recommended by the RAS, and ventilation with dry and heated air to overcome the dormancy and the germination performance of six seed lots Bracharia humidicola cv. Tully. The work performed comparisons between the physiological effects of heat treatments at 45, 55, 65 and 75 ºC, during 24 and 48 hours periods and chemical scarification (immersion in concentrated sulfuric acid) for 10 minutes, constituting eight treatments and two controls. The experiment was conducted in a completely randomized design with four replications. The seed germination, the germination velocity index, the tetrazolium test and seedling dry weight were evaluated. The use of controlled temperatures and of H2SO4 are mechanisms to overcome dormancy, but in greater vitality batches results were equal to conventional treatment with sulfuric acid, which can be considered as an alternative. Generally, the work did not indicate the best period (24 or 48 hours), for use with dry air ventilation, however a temperature of 60 °C for lots with high vitality (L1, L3 and L5) may be recommended. The H2SO4 use in lots with greater vitality was not statistically significant compared with the control, but for lots with less vitality physiological deterioration occurred in the seeds.
O ácido sulfúrico tem mostrado eficiência na superação da dormência em sementes, porém o uso do mesmo traz riscos efetivos aos trabalhadores e ao meio ambiente. O trabalho foi conduzido com o objetivo estudar a efetividade do tratamento com ácido sulfúrico, preconizado pelas RAS, e o emprego de ventilação com ar seco e aquecido na superação da dormência e desempenho germinativo de sementes de seis lotes de capim Brachiaria humidicola cv. Tully. O trabalho realizou comparações entre os efeitos fisiológicos de tratamentos térmicos de 45, 55, 65 e 75ºC, com períodos de 24 e 48 horas e o químico (imersão em ácido sulfúrico concentrado) por 10 minutos, constituindo-se oito tratamentos e duas testemunhas. O experimento foi conduzido em delineamento inteiramente casualizado com quatro repetições. Foram avaliados a germinação das sementes, o índice de velocidade de germinação, o teste de tetrazólio e a massa seca das plântulas. O uso de temperaturas variadas e controladas e o uso convencional de H2SO4 são mecanismos de superação de dormência, porém em lotes com maior vitalidade ocorreram resultados iguais ao tratamento convencional com ácido sulfúrico, podendo ser considerado uma alternativa. De maneira geral, o trabalho não indicou o melhor período (24 ou 48h), para emprego da ventilação com ar seco, entretanto a temperatura de 60°C, para os lotes de maior vitalidade (L1, L3 e L5), pode ser recomendada. O H2SO4 nos lotes com maior vitalidade não mostrou significância estatística em relação à testemunha, porém para os lotes com menor vitalidade ocorreu deterioração fisiológica da semente.
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Costa, Adilson da. "Estudo das mudanças quali e quantitativas da participação de ácidos graxos no sebo de pacientes com acne inflamatória, graus II ou III, em uso sistêmico de limeciclina e/ou suplementação oral à base de ácidos linoleico, gamalinolênico." Universidade de São Paulo, 2012. http://www.teses.usp.br/teses/disponiveis/5/5133/tde-26042012-115056/.
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Introdução: Acne é uma dermatose que apresenta o padrão do sebo alterado, tanto quali, quanto quantitativamente. Objetivos: Estudar as possíveis alterações quali e quantitativas dos ácidos graxos encontrados no sebo de portadores de acne vulgar graus II ou III mediante ao uso diário de limeciclina e/ou suplemento oral a base de ácidos linoleico, gamalinolênico e oleico. Métodos: Quarenta e cinco sujeitos de pesquisa masculinos, de 12 a 40 anos de idade, portadores de acne vulgar graus II ou III, submeteram-se a 90 dias de uso de: Grupo A, 300mg/dia de limeciclina; Grupo B, 540mg de ácidos gamalinolênico, 1.200mg linoleico e 510mg oleico/dia; Grupo C: Grupos A+B. A cada 30 dias, eles tinham amostra de sebo da fronte coletada para análise cromatográfica dos ácidos graxos nele presentes. Resultados: Quarenta sujeitos de pesquisa (88,9%) concluíram o estudo, os quais ingeriram todas as doses dos produtos, sem apresentarem eventos adversos em qualquer dos Grupos. O número de comedões, pústulas e cistos reduziu com o tempo (p<0,001, para todos), nos três Grupos. Com relação ao número total de lesões, houve uma maior quantidade de lesões em pacientes do Grupo B, quando comparados aos do Grupo A (p=0,033) e aos do Grupo C (p=0,030). Sete ácidos graxos apresentaram mudanças de seu padrão durante o estudo. De um modo geral, as mudanças que se tornaram mais evidentes foram: 1) a concentração de esqualeno no SB não reduziu em qualquer Grupo de estudo; 2) C12:0, C14:0 e C16:1 tiveram suas respectivas concentrações aumentadas nos três Grupos com o tempo de terapêuticas; 3) há indicativo de aumento de C18:1n9c+C18:1n9t na associação das duas classes terapêuticas estudadas; 4) limeciclina e/ou ingestão de ácido linoleico não aumentaram a participação do ácido linoleico no sebo; 5) ácido -linolênico teve sua concentração aumentada e, depois diminuída com o uso de LM e/ou com sua própria suplementação oral. Conclusões: A administração diária de limeciclina e/ou ácidos gamalinolênico, linoleico e oleico pode alterar o comportamento de alguns dos ácidos graxos presentes no sebo de pacientes portadores de acne vulgar graus II ou III. Os ácidos gamalinolênico, linoleico e oleico, se no uso sistêmico, não são considerados agentes terapêuticos na abordagem da acne; mais estudos precisam ser realizados a fim de se inferir a existência de possível benefício clínico de seu uso isolado e/ou associado na abordagem desta dermatoseIntroduction: Acne is a dermatosis that presents an altered sebum pattern, quantitatively and qualitatively. Objectives: To study the possible quantitative and qualitative changes of fatty acids found in the sebum of patients with acne vulgaris grade II or III, through the daily use of lymecycline and/or oral supplementation based on linoleic, gamma-linolenic, and oleic acids. Methods: Fortyfive male research subjects, ages 12 to 40, presenting acne vulgaris grade II or III, were submitted to a 90-day use of: Group 1, 300mg of lymecycline per day; Group 2, 540mg of gamma-linolenic acid, 1,200mg of linoleic acid, and e 510mg of oleic acid per day; Group 3: Groups A+B. Every 30 days, a sample of the sebum of their forehead was collected for chromatographic analysis of the fatty acids contained therein. Results: Forty research subjects (88.9%) concluded the study. They ingested all dosages of the products, without presenting side effects in any of the Groups. The number of comedones, pustules, and cysts reduced with time (p<0.001, for all), in all the 3 Groups. With respect to the total number of lesions, Group B´s patients presented a larger quantity of lesions, as compared to those of Group A (p=0.033) and Group C (p=0.030). Seven fatty acids presented pattern changes during the study. In general, the changes that became more evident were: 1) the squalene concentration in the sebum did not diminish in any Group under study; 2) C12:0, C14:0, and C16:1 had their respective concentrations increased in the 3 Groups over the time of the treatments; 3) there is an indication for increasing of C18:1n9t+C18:1n9c when both of therapies are associated; 4) lymecycline and/or the ingestion of linoleic acid did not increase the participation of linoleic acid in the sebum; and 5) gama-linolenic acid had its concentration increased during the first 60-day and diminished during the last 30-day therapies period using lymecycline and/or with its own oral supplementation. Conclusions: The daily administration of lymecycline and/or gamma-linolenic, linoleic, and oleic acids may alter the behavior of some fatty acids present in the sebum of patients with acne vulgaris grade II or III. Gamma-linolenic, linoleic, and oleic acids, under systemic use, are not considered therapeutic agents in the treatment of acne; more studies need to be carried out in order to infer the existence of a possible clinical benefit of their isolated use and/or association in the treatment of this dermatosis
Book chapters on the topic "Seco acids"
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Abushanab, Elie. "L-Ascorbic and D-Isoascorbic Acids: Chiron Sources for 1′,2′ -SECO-Nucleosides/Tides, Phosphonates, and Other Molecules of Biological Interest." In Nucleosides and Nucleotides as Antitumor and Antiviral Agents, 159–75. Boston, MA: Springer US, 1993. http://dx.doi.org/10.1007/978-1-4615-2824-1_9.
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Ōsawa, Eiji, Eugen Deretey, and Hitoshi Gotō. "Conformational Analysis of Long Chain Seco-Acids Used in Woodward’s Total Synthesis of Erythromycin A — Conformational Space Search as the Basis of Molecular Modeling." In Fundamental Principles of Molecular Modeling, 189–97. Boston, MA: Springer US, 1996. http://dx.doi.org/10.1007/978-1-4899-0212-2_10.
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Calvert, Jack, Abdelwahid Mellouki, John Orlando, Michael Pilling, and Timothy Wallington. "Rate Coefficients and Mechanisms for the Atmospheric Oxidation of the Organic Acids." In Mechanisms of Atmospheric Oxidation of the Oxygenates. Oxford University Press, 2011. http://dx.doi.org/10.1093/oso/9780199767076.003.0009.
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Organic acids, particularly formic and acetic acid, are ubiquitous components of the troposphere (Chebbi and Carlier, 1996); see table I-D-1. However, the atmospheric budget of these species is at present poorly constrained, and global models often underestimate their abundance (von Kuhlmann et al., 2003). The presence of organic acids in the atmosphere can be attributed to two distinct mechanisms: direct emission from anthropogenic and natural sources; and in situ production via gas-phase or condensed-phase chemistry. Direct emissions result from biomass burning (e.g., Christian et al., 2007), from motor vehicle use (Kawamura et al., 2000) and other anthropogenic activities (see chapter I), and from biogenic sources (e.g., Seco et al., 2007). Production in the gas phase can occur via the reactions of acylperoxy radicals with HO2: . . . CH3C(O)O2 + HO2 → CH3C(O)OOH + O2 . . . . . . CH3C(O)O2 + HO2 → CH3C(O)O + OH + O2 . . . . . . CH3C(O)O2 + HO2 → CH3C(O)OH + O3 . . . or via the ozonolysis of unsaturated species (Orzechowska and Paulson, 2005a, b). Additional in situ acid production (particularly with multi-functional species and diacids) likely occurs in the condensed phase as well, via the oxidation of carbonyl and other oxygen-containing and multi-functional organics (e.g., Ervens et al., 2004). In general, the organic acid moiety, —C(O)OH, is rather unreactive in the gas phase. This is in large part due to the strength of the O—H bond, ∼460 kJ mole−1 versus 400–420 kJ mole−1 for typical C—H bonds (Sander et al., 2006). The organic acid moiety also acts to inhibit somewhat the reactivity of neighboring sites (Kwok and Atkinson, 1995), further decreasing the reactivity of small saturated acids. UV spectra for unsubstituted acids are located at relatively short wavelengths, [e.g., λmax< 210 nm for acetic acid, Orlando and Tyndall (2003); see figure IX-A-1], so tropospheric photolysis is of negligible importance. Thus, the gas-phase lifetime for small saturated organic acids (e.g., formic and acetic acid) can be quite long, about 1 month.
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Singh, S. "Electrochemical Oxidation of Perfluorooctanoic Acid (PFOA) from Aqueous Solution using Non-Active Ti/SnO2-Sb2O5/PbO2 Anodes." In Advances in Wastewater Treatment II, 48–67. Materials Research Forum LLC, 2021. http://dx.doi.org/10.21741/9781644901397-2.
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In this study, electrochemical oxidation of perfluorooctanoic acid (PFOA, C7H15CO2H) from aqueous solution was examined in terms of PFOA and total organic carbon (TOC) removal by using Ti/SnO2-Sb2O5/PbO2non-active electrodes. The effects of operating parameters: initial pH (pHo), current density (j), and electrolyte concentration (m) at different time intervals were examined. Specific energy consumption (SEC) was used to determine the process proficiency. The C-C bond between C7F15 was first cleaved and thendegraded into fluoride ions (F−) and short carbon-chain per-fluorinated carboxylic acids (PFCAs) ((∼C2−C7) such as perfluoroethanoic acid (PFEA: C2F5CO2H), perfluoropropanoic acid (PFPA: C3F7CO2H), perfluorobutanoic acid (PFBA: C4F9CO2H), perfluoropentanoic acid (PFPeA: C5F11CO2H), perfluorohexanoic acid (PFHxA: C6F13CO2H), perfluoheptanoic acid (PFHpA: C7F14CO2H). These intermediates by-products were determined using the gas chromatograph-mass spectrometry (GC/MS) analysis. The rate of PFOA decomposition was followed the pseudo-first-order kinetics. About 82%TOC and 94% PFOA removals were formed at the optimal condition of pHo = 3.58, j=168.34 Am-2, and m = 250 mgL-1 at 120 min of electrolysis with SEC = 593 kWh/kg TOC. A plausible degradation mechanism was also proposed at the optimal treatment condition.
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Wilson, Ian, and Jungwoo Choe. "Structural Analysis of Toll-Like Receptors." In Nucleic Acids in Innate Immunity, 3–15. CRC Press, 2008. http://dx.doi.org/10.1201/9781420068269.sec1.
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Haas, Tobias, Frank Schmitz, Hermann Wagner, and Antje Heit. "Natural DNA Recognition by Toll-Like Receptor 9 Does Not Rely upon CpG Motifs." In Nucleic Acids in Innate Immunity, 77–83. CRC Press, 2008. http://dx.doi.org/10.1201/9781420068269.sec2.
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"Ascorbic Acid." In Vitamin Analysis for the Health and Food Sciences. CRC Press, 1998. http://dx.doi.org/10.1201/9781420050165.sec2.
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Saleh, Lana, and Christopher J. Noren. "Site-directed Chemical Modification of Phage Particles." In Phage Nanobiotechnology, 202–19. The Royal Society of Chemistry, 2011. http://dx.doi.org/10.1039/bk9780854041848-00202.
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The ability to chemically modify the surface of bacteriophage bypasses the functional limitations imposed by the standard biosynthetically incorporated amino acids that comprise the phage coat. Appended functionalities can include fluorescent or other reporter groups, inorganic materials, cytotoxic agents, and pharmacophores. Applications include incorporating the modification in the context of a displayed random peptide library prior to panning as a route to chimeric semisynthetic peptide ligands, use of phage as a template for construction of novel nanomaterials, direct mechanical manipulation of phage, use of phage particles as medical imaging reagents, and catalysis-based screening for novel enzyme activities. Site-specific modification of phage in the context of the forest of competing functional groups that make up the phage coat requires a uniquely reactive chemical group specifically placed in the coat protein. The so-called “21st amino acid” selenocysteine (Sec) is found in all three kingdoms of life and is co-translationally incorporated via a context-dependent opal suppression mechanism. The lower pKa of Sec (5.2 vs. 8.3 for cysteine) permits modification by direct nucleophilic substitution at low pH values, where other nucleophilic amino acids are essentially unreactive. Incorporation of Sec-insertion signals into the phage coat protein gene gIII results in quantitative site-specific incorporation of Sec, which can, in principle, be modified with any novel chemical group. The use of phage-displayed selenopeptides for chimeric library screening, enzyme evolution, and direct mechanical manipulation of phage will be discussed in this chapter.
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Luo, Hong, Haibo Liu, and Christian Baldwin. "Acid Soil and Aluminum Tolerance in Turfgrasses." In Handbook of Turfgrass Management and Physiology, 375–88. CRC Press, 2007. http://dx.doi.org/10.1201/9781420006483.sec8.
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Reed, Lester. "A Trail of Research on Lipoic Acid." In Oxidative Stress and Disease. CRC Press, 2008. http://dx.doi.org/10.1201/9781420045390.sec1.
Full textConference papers on the topic "Seco acids"
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Zheng, Ying, Harry Zhou, Zhijiang Chen, and Nnanna N. Ekedebe. "Automated analysis and evaluation of SEC documents." In 2014 IEEE/ACIS 13th International Conference on Computer and Information Science (ICIS). IEEE, 2014. http://dx.doi.org/10.1109/icis.2014.6912118.
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Ying Zheng and Harry Zhou. "An Intelligent Text Mining System Applied to SEC Documents." In 2012 IEEE/ACIS 11th International Conference on Computer and Information Science (ICIS). IEEE, 2012. http://dx.doi.org/10.1109/icis.2012.124.
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Hua, Younan, Li Xiaomin, Lois Liao, Yuanyuan Liu, and Linhua Zhang. "Studies and Applications of a New Delineation Method of Silicon Defects in Wafer Fabrication." In ISTFA 2022. ASM International, 2022. http://dx.doi.org/10.31399/asm.cp.istfa2022p0365.
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Abstract In wafer fabrication, silicon defects on the substrate directly affect the yield of the wafer. In this paper, we will study and discuss a chemical delayering and delineate method for silicon defects in wafer fabrication using Secco etch. It is well-known that during delayering process of wafer, the removal of polysilicon (Poly-Si) layer is very difficult, especially for the wide-layer polysilicon (Poly-Si) which is difficult to completely remove with HF acid solution. We introduce a chemical recipe to fast delayer polysilicon layer completely before delineating silicon defects on silicon substrate using Secco etch. Those skilled in the art could be experiment within half an hour to get analysis results. It saves time and improves operational efficiency. Moreover, based on the experimental results we think that it is possible to identify the root cause according to the shapes of silicon defects using Secco etch.
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Lee, Gija, Seokkeun Choi, Sungwook Kang, Samjin Choi, Jeonghoon Park, Dong Hyun Park, Youngho Park, Kyungsook Kim, Bermseok Oh, and Hunkuk Park. "Changes in Extracellular Glutamate Release on Repetitive Transient Occlusion in Global Ischemia Model." In ASME 2009 Summer Bioengineering Conference. American Society of Mechanical Engineers, 2009. http://dx.doi.org/10.1115/sbc2009-206602.
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During the operation, surgeons in neurosurgical area usually performed the multiple temporary occlusions of parental artery which may induce the neuronal damage. It is generally thought that neuronal damage by cerebral ischemia is associated with extracellular concentrations of the excitatory amino acids. In this experiment, we measured the dynamics of extracellular glutamate release in 11 vessel occlusion (VO) model during repeated within short interval. Changes in cerebral blood flow were monitored by laser-Doppler flowmetry simultaneously with cortical glutamate level measured by amperometric biosensor. During ischemia, the peak level of glutamate release was gradually decreased as 112.38±26.21 μM in first period, 82.63±18.50 μM in second period, and 48.58±11.89 μM in third period. The time interval between the ischemia induction and the beginning of glutamate release was increased as 106.7 ± 10.89 (sec) at first attack, 139.11 ± 3.87 (sec) in second attack, 169.00 ± 14.56 (sec) in third ischemic period. From the results of real-time monitoring about glutamate release in 11-VO model during repetitive ischemic episode, it was demonstrated that repetitive ischemia induced less glutamate release from neuronal cell than single ischemia due to endogeneous protective mechanism which delayed glutamate release time in later ischemic injury.
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KHOO, B. C., D. XU, W. Y. D. YUEN, and W. K. SOH. "A COMPUTER ANALYSIS OF TURBULENT FLOW OF ACID IN THE PICKLING OF STEEL STRIPS." In Proceedings of the International Conference on Scientific and Engineering Computation (IC-SEC) 2002. PUBLISHED BY IMPERIAL COLLEGE PRESS AND DISTRIBUTED BY WORLD SCIENTIFIC PUBLISHING CO., 2002. http://dx.doi.org/10.1142/9781860949524_0039.
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Wang, Mengmeng, Keiko Sasaki, Hirofumi Akamatsu, and Ismaila Dabo. "Environmental impact of amino acids on the stability of hydrotalcite after bearing SeO42- integrated with DFT simulation." In Goldschmidt2021. France: European Association of Geochemistry, 2021. http://dx.doi.org/10.7185/gold2021.5939.
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Tyapkina, D. Yu, E. Z. Kochieva, and M. A. Slugin. "Biochemical and molecular genetic aspects of the metabolism of L-ascorbic acid invarieties and wild species of tomato (Solanum sect. Lycopersicon)." In IX Congress of society physiologists of plants of Russia "Plant physiology is the basis for creating plants of the future". Kazan University Press, 2019. http://dx.doi.org/10.26907/978-5-00130-204-9-2019-445.
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Mirci, Liviu E., Sorina Boran, Paula Luca, and Victor Boiangiu. "Synthetic Lubricants Based on Sebacic Complex Esters." In World Tribology Congress III. ASMEDC, 2005. http://dx.doi.org/10.1115/wtc2005-63049.
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The paper present the results carried out in order to produce synthetic ester oils with a complex structure on the basis of sebacic acid with beneficial tribological properties. Three series of unsymmetrical diesters have been synthesized by taking into account superior aliphatic alcohols such as 2-ethyl-hexanol, isodecanol and isotridecanol along with special alcohols of a complex alkyl-aryl structure, namely 2-phenoxy-ethanol, 2-[(o sec butyl)-phenoxy] ethanol and 2-[(p-nonyl)-phenoxy] ethanol, respectively. There were also synthesized the symmetrical (homogeneous) esters based on these special aliphatic-aromatic alcohols.
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De Clerck, F., B. Xhonneux, L. Van Gorp, J. Beetens, and P. A. J. Janssen. "S2-SEROTONERGIC RECEPTOR INHIBITION (KETANSERIN), COMBINED WITH THROMBOXANE A2/PROSTAGLANDIN ENDOPEROXIDE RECEPTOR BLOCKADE (BM 13177) : ENHANCED ANTI-PLATELET EFFECT." In XIth International Congress on Thrombosis and Haemostasis. Schattauer GmbH, 1987. http://dx.doi.org/10.1055/s-0038-1643464.
Full textAbstract:
Subsequent to an initial activation, several products are released from the platelets, and -potentially- contribute to the recruitment of new cells to build up the eventual platelet haemostatic plug or thrombus. Among the various accussates, serotonin as well as the arachidonic acid derivatives thromboxane A2 (TXA2) and prostaglandin endoperoxides (PGEND) seem to be involved as causative mediators, in particular when acting in concert on the same target cells. Indeed, in vitro at concentrations achievable after oral administration to man, either ketanserin (K), an S2-serotonergic receptor antagonist or BM 13177 (BM), an antagonist at TXA2/PGEND receptors, pre-incubated separately for 5 rain at 37°C with human citrated platelet-rich plasma, reduces to some extent the rate of the second-wave, irreversible platelet aggregation elicited by critical concentrations (1 to 2 × 10−6 M) of ADP. However, the combindation of both agonists results in a significantly more pronounced inhibition than achieved with the single products (K 1 × 10−7 M : 26.1 ± S.E.M. 9.9 %, n = 8. p < 0.05; BM 1 × 10−77 M : 25.1 ± S.E.M. 8.7%, n = 8, p < 0.05; K ± BM at 1 × 10−7 M each ; 65.5 ± S.E.M. 10.3 %, n = 8; p < 0.05 versus K or BM separately). In vivo in rats, a modest prolongation of the bleeding time occurs with K (1.25 mg/kg orally -2 h : 410 sec, median values n = 9, p < 0.05) but not with BM (40 mg/kg orally, -2 h : 250 sec, n = 9) in comparison with controls (190 sec, n = 9); the amount of initial blood loss as a parameter for anti-vasoconstriction is significantly increased by K (140.4 μl/30 sec) but not by BM (77.2 μl/30 sec) in comparison with controls (35 μl/30 sec). Again, the combined treatment with both agonists results in a marked prolongation of the bleeding times (> 2065 sec, n = 9, p < 0.05) without further significant increase of the initial blood loss, indicating the interplay between serotonin and TXA2/PGEND to be of primary importance for the aggregation of platelets in damaged vessels.
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Crook, M., S. J. Machin, and N. Crawford. "PLATELET SUBPOPULATION HETEROGENEITY IN IDIOPATHIC THROMBO-CYTOPAENIA AND ESSENTIAL THROMBOCYTHAEMIA STUDIED BY CONTINUOUS FLOW ELECTROPHORESIS: MORPHOLOGICAL AND BIOCHEMICAL CHARACTERISATION." In XIth International Congress on Thrombosis and Haemostasis. Schattauer GmbH, 1987. http://dx.doi.org/10.1055/s-0038-1644576.
Full textAbstract:
Using continuous flow electrophoresis (CFE) normal human platelets have been separated into a surface-charge dependent profile (roughly gaussian) extending over 15-20 fractions with an electrophoretic mobility range between 0.86 and 0.93 μmetres/sec Volt cm. The technique has also been used to study platelets from adult patients with Stable Essential Thrombocythaemia (platelet counts - 600-800 × 109/L) and chronic Idiopathic Thrombocytopaenia (counts 15-80 × l09/L). Neither group was receiving specific therapy during the investigations. The platelets from both patient groups showed significant anodal shifts in electrophoretic mobilities in comparison with the CFE profiles from normal adults. Sialic acid, a negatively charged sugar moiety, associated with membrane glycoproteins is a major contributor to the platelet surface electronegativity and both total platelet sialic acid and surface neuraminidase-labile sialic acid measurements were made using the thiobarbituric acid procedure. Platelets from the Idiopathic Thrombocytopaenic group showed (with respect to normal levels) significant increases in both total and neuraminidase-labile sialic acid (expressed in terms of platelet number). Platelets from the Essential Thrombocythaemic group did not differ significantly in sialic acid contents from platelets from normal subjects. Platelet sizes (Coulter counter volumes) were also measured across the normal and patient platelet electrophoretic profiles together with morphological monitoring. In platelets from ITP patients these more electronegative platelets were substantially larger and of more bizarre shapes than those of normal patients when viewed with scanning and transmission electron microscopy, whereas platelets from the Essential Thrombocythaemic group showed less significant volume increases. These findings of marked changes in platelet surface electrokinetic and analytical properties in patients with the two disorders suggest that studies in other disease states, involving disturbances of thrombokinetics, may be warranted and particularly should be followed through therapeutic programmes.
Reports on the topic "Seco acids"
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Porat, Ron, Gregory T. McCollum, Amnon Lers, and Charles L. Guy. Identification and characterization of genes involved in the acquisition of chilling tolerance in citrus fruit. United States Department of Agriculture, December 2007. http://dx.doi.org/10.32747/2007.7587727.bard.
Full textAbstract:
Citrus, like many other tropical and subtropical fruit are sensitive to chilling temperatures. However, application of a pre-storage temperature conditioning (CD) treatment at 16°C for 7 d or of a hot water brushing (HWB) treatment at 60°C for 20 sec remarkably enhances chilling tolerance and reduces the development of chilling injuries (CI) upon storage at 5°C. In the current research, we proposed to identify and characterize grapefruit genes that are induced by CD, and may contribute to the acquisition of fruit chilling tolerance, by two different molecular approaches: cDNA array analysis and PCR cDNA subtraction. In addition, following the recent development and commercialization of the new Affymetrix Citrus Genome Array, we further performed genome-wide transcript profiling analysis following exposure to CD and chilling treatments. To conduct the cDNA array analysis, we constructed cDNA libraries from the peel tissue of CD- and HWB-treated grapefruit, and performed an EST sequencing project including sequencing of 3,456 cDNAs from each library. Based on the obtained sequence information, we chose 70 stress-responsive and chilling-related genes and spotted them on nylon membranes. Following hybridization the constructed cDNA arrays with RNA probes from control and CD-treated fruit and detailed confirmations by RT-PCR analysis, we found that six genes: lipid-transfer protein, metallothionein-like protein, catalase, GTP-binding protein, Lea5, and stress-responsive zinc finger protein, showed higher transcript levels in flavedo of conditioned than in non-conditioned fruit stored at 5 ᵒC. The transcript levels of another four genes: galactinol synthase, ACC oxidase, temperature-induced lipocalin, and chilling-inducible oxygenase, increased only in control untreated fruit but not in chilling-tolerant CD-treated fruit. By PCR cDNA subtraction analysis we identified 17 new chilling-responsive and HWB- and CD-induced genes. Overall, characterization of the expression patterns of these genes as well as of 11 more stress-related genes by RNA gel blot hybridizations revealed that the HWB treatment activated mainly the expression of stress-related genes(HSP19-I, HSP19-II, dehydrin, universal stress protein, EIN2, 1,3;4-β-D-glucanase, and SOD), whereas the CD treatment activated mainly the expression of lipid modification enzymes, including fatty acid disaturase2 (FAD2) and lipid transfer protein (LTP). Genome wide transcriptional profiling analysis using the newly developed Affymetrix Citrus GeneChip® microarray (including 30,171 citrus probe sets) revealed the identification of three different chilling-related regulons: 1,345 probe sets were significantly affected by chilling in both control and CD-treated fruits (chilling-response regulon), 509 probe sets were unique to the CD-treated fruits (chilling tolerance regulon), and 417 probe sets were unique to the chilling-sensitive control fruits (chilling stress regulon). Overall, exposure to chilling led to expression governed arrest of general cellular metabolic activity, including concretive down-regulation of cell wall, pathogen defense, photosynthesis, respiration, and protein, nucleic acid and secondary metabolism. On the other hand, chilling enhanced various adaptation processes, such as changes in the expression levels of transcripts related to membranes, lipid, sterol and carbohydrate metabolism, stress stimuli, hormone biosynthesis, and modifications in DNA binding and transcription factors.