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Enantiomeric Separation of S-Epichlorohydrin and R-Epichlorohydrin by Capillary Gas Chromatography with FID Detector 被引量:1
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作者 Cholleti Vijay kumar pavan kumar Vasa +2 位作者 Y. Ravindra kumar Pasula Aparna Padi Pratyusha 《American Journal of Analytical Chemistry》 2016年第11期772-784,共13页
The aim of this study was to develop a simple and derivatization free method for the Quantification of S-Epichlorohydrin in R-Epichlorohydrin by using a gas chromatography coupled with flame ionization detector (FID).... The aim of this study was to develop a simple and derivatization free method for the Quantification of S-Epichlorohydrin in R-Epichlorohydrin by using a gas chromatography coupled with flame ionization detector (FID). Enantiopure epichlorohydrin was a valuable epoxide key starting material for preparing optically active Rivaroxaban. The enantiomeric separations of S-Epichlorohydrin and R-Epichlorohydrin were achieved on Gamaa-Dex-225 (30 meters × 0.25 mm I.D, 0.25 μm) column with a total run time of 30 min. Nitrogen was used as a carrier gas with constant pressure 25.0 psi. The critical experimental parameters such as, column selection, flow rate, injection volume and diluent were studied and optimized. Excellent correlation coeffient between peak responses and concentrations was >0.9998. The recoveries of S-Epichlorohydrin spiked in R-Epichlorohydrin were in the range from 98.2% to 102.8%. Limit of quantitation for S-Epichlorohydrin was sufficiently lower than limits specified by ICH. The method has validated as per International Conference on Harmonization (ICH) guidelines. A precise, accurate, linear and robust Gas Chromatography method was developed for the quantification of S-Epichlorohydrin in R-Epichlorohydrin for Rivaroxaban. 展开更多
关键词 S-Epichlorohydrin R-Epichlorohydrin Method Development ICH Guidelines Method Validation Gas Chromatography
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A New and Enantioselective Chromatographic Method for Linagliptin on Amylose Coated Chiral Stationary Phase
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作者 Cholleti Vijay kumar Pasula Aparna +2 位作者 pavan kumar Vasa Y. Ravindra kumar Nitin Haridas Dhekale 《American Journal of Analytical Chemistry》 2016年第7期556-567,共12页
A new and enantioselective liquid chromatographic method was developed for estimation of S-Linagliptin in Linagliptin (LINA) drug substances. The desired enantiomeric separation was achieved on Chiralpak AD-H (250*4.6... A new and enantioselective liquid chromatographic method was developed for estimation of S-Linagliptin in Linagliptin (LINA) drug substances. The desired enantiomeric separation was achieved on Chiralpak AD-H (250*4.6 mm*5 μm) column with the mobile phase composition of ethanol, methanol and diethylamine in a ratio of 90:10:0.1 (v/v/v) with flow rate of 0.5 mL·min<sup>-</sup><sup>1</sup> and column oven temperature 30°C and the eluted compounds were monitored at 225 nm. In the proposed chiral method, USP resolutions between both the enantiomers were more than 5.0. Limit of detection and Limit of quantitation of S-LINA was found to be 0.03 μg·mL<sup>-1</sup> and 0.10 μg·mL<sup>-1</sup> respectively. Linearity study was conducted from LOQ to 150% and correlation coefficient found to be 0.9997. Accuracy was within the range of 98.6% to 101.5%. To prove selectivity power of the method specificity study was conducted by subjecting drug substance to acid, base, hydrolysis, oxidation and photolysis and ensured the peak purity of analyte in degraded samples. Moreover, the method has been fully validated as per ICH guidelines. The proposed method is precise, accurate, linear, rugged, robust and suitable for accurate quantification of S-LINA in LINA drug substance. 展开更多
关键词 ENANTIOMERS Amylose Based Stationary Phase Method Development Method Validation SPECIFICITY
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Characterization of Islets from Chronic Calcific Pancreatitis Patients of Tropical Region with Distinct Phenotype
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作者 P. pavan kumar M. Sasikala +4 位作者 K. Mamatha G. V. Rao R. Pradeep R. Talukdar D. Nageshwar Reddy 《Advances in Bioscience and Biotechnology》 2016年第1期1-10,共10页
Background and Objective: Islet autotransplantation is performed to preserve endocrine function in patients undergoing pancreatic resections for painful chronic pancreatitis. We characterized islets isolated from chro... Background and Objective: Islet autotransplantation is performed to preserve endocrine function in patients undergoing pancreatic resections for painful chronic pancreatitis. We characterized islets isolated from chronic pancreatitis patients (CP) of tropical region. Patients and Methods: Pancreatic tissues were obtained from CP patients with and without diabetes undergoing pancreatic resections (n = 35) and brain-dead multi organ donors (n = 6;considered as controls). Islets isolated were assessed for yield, purity, viability and in vitro islet function (Glucose stimulated insulin release, GSIR) as per standard protocols. Results: Islets from CP patients without diabetes were similar to controls in yield (control 4120 - 6100 IE/g, CP 3550 - 5660 IE/g), purity (control 78% ± 12%, CP 70% ± 8.2%) and viability (control 85% ± 8%, CP 81% ± 10%) and islets from CP patients with diabetes showed decreases in yield (3002 - 2300 IE/g), purity (61% ± 16%) and viability (62% ± 21%). Islets measuring 50 - 200 μ were similar in abundance in controls (94.74% ± 3.2%) and CP patients with and without diabetes, 86.31% ± 4.9%, 91.03% ± 3.8%. GSIR of islets from CP patients and controls were similar at 5.5 mM glucose (2.8 - 3.1 μU/ml). However, GSIR at 16.5 mM glucose was decreased in CP patients (control 18.5 ± 0.6, CP without diabetes 11.8 ± 0.3, CP with diabetes 4.3 ± 0.3 μU/ml). Conclusion: Our results demonstrate suitability of islets isolated from CP patients of tropical region for autotransplantation. 展开更多
关键词 ISLETS Tropical Chronic Pancreatitis Islet Functions TRANSPLANTATION
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Dysregulated miRNA Associated with Transcription Factors of Insulin Gene Expression in Chronic Pancreatitis
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作者 K. Murali Manohar M. Sasikala +2 位作者 P. pavan kumar G. V. Rao D. Nageshwar Reddy 《Open Journal of Endocrine and Metabolic Diseases》 2016年第10期205-227,共24页
Background/Aim: MicroRNAs with regulatory functions in gene expression are implicated in different diseases. The present study investigated differentially expressed miRNAs that possibly influence transcription factors... Background/Aim: MicroRNAs with regulatory functions in gene expression are implicated in different diseases. The present study investigated differentially expressed miRNAs that possibly influence transcription factors involved in insulin gene expression in Chronic Pancreatitis (CP) employing bioinformatics approaches. Methods: Pancreatic tissues were collected from CP patients undergoing partial pancreatectomy (n = 16) and controls (n = 15) undergoing resections for non-pancreatic malignancies. MiRNA profiles obtained using microarrays were validated by qRT-PCR. Target search involving miRWalk and TarBase as well as functional annotation employing KEGG (Kyoto encyclopedia of genes and genomes) and DAVID (Database for Annotation) databases were performed. Ingenuity pathway analysis (IPA) was used to construct networks relating miRNAs to their target genes. mRNA and proteins related to insulin gene transcription factors and hormones were evaluated by qRT-PCR and western blotting followed by confirmation upon immunofluorescent staining. Results: Microarray data revealed 10 up-regulated and 15 down-regulated miRNAs in CP as compared to controls (Log2 FC > 2). Bioinformatic analysis showed 8399 target genes and KEGG pathway analysis suggested a role for the dysregulated miRNAs in modulating cytokine signaling, fibrosis, JAK-STAT signaling and insulin synthesis. IPA analysis suggested a simplified network attributing dysregulated miRNAs to NFκB-dependent cytokine signaling. Further, associations could be noted between miRNA 200b with Maf A, 138-1 with Neuro D and 27b with FoxO1. Decreases in mRNA levels of Pdx1, Neuro D and increases of Maf A and FoxO1 transcription factors could be noted (P Conclusion: Our results identified dysregulation of miRNAs 138-1, 27b and 200b which were found to be associated with insulin gene transcription factors Neuro D, FoxO1 and Maf A respectively. 展开更多
关键词 MICRORNAS Transcription Factors Networks β-Cell Dysfunction
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熔融纺弹性纤维——弹性纤维技术与市场改变者
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作者 J.Thiel P.K.Manvi +6 位作者 I.Stappen T.B.M.Zhang T.Gries D.Cornils B.Minke 冯子卿(译) 孟粉叶(校) 《国际纺织导报》 2022年第12期4-5,24,共3页
在过去几年,适用于服装和医用纺织品的弹性纱线市场需求增长迅速。目前,弹性纱线主要通过干法纺丝工艺生产,但弹性纱线的这种生产方式存在生产速度低、生产成本高、溶剂影响环境及纱线表面高黏性4个方面的局限性,从而使弹性纤维的进一... 在过去几年,适用于服装和医用纺织品的弹性纱线市场需求增长迅速。目前,弹性纱线主要通过干法纺丝工艺生产,但弹性纱线的这种生产方式存在生产速度低、生产成本高、溶剂影响环境及纱线表面高黏性4个方面的局限性,从而使弹性纤维的进一步加工变得极为困难。ElasKosTex研究项目利用开发的熔融纺弹性双组分长丝作为这一问题的解决方案。 展开更多
关键词 熔融纺弹性双组分纤维 ElasKosTex研究项目 皮芯复合熔融纺丝
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热塑性聚氨酯无溶剂熔融纺丝工艺替代传统溶液纺丝工艺
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作者 P.K.Manvi T.Gries +1 位作者 乔士亚(译) 于俊荣(校) 《国际纺织导报》 2020年第11期8-10,共3页
聚氨酯是一类弹性共聚物,以伸长率高和弹性非常好而著称。聚氨酯聚合物可具有不同的硬度等级,这使其应用范围广泛,如包装、密封、涂层及纺织品等。伸长率和弹性被认为是纺织品的重要性能,因为这些性能在纺织品的穿着舒适性和形状保持性... 聚氨酯是一类弹性共聚物,以伸长率高和弹性非常好而著称。聚氨酯聚合物可具有不同的硬度等级,这使其应用范围广泛,如包装、密封、涂层及纺织品等。伸长率和弹性被认为是纺织品的重要性能,因为这些性能在纺织品的穿着舒适性和形状保持性方面起着重要作用。据研究,80%的服装含有不同比例的弹性长丝。这表明服装工业中不可避免地会使用弹性长丝。概述了聚氨酯的性能、长丝生产工艺及其熔融纺丝工艺的最新进展。 展开更多
关键词 热塑性聚氨酯 熔融纺丝 无溶剂
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