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Effects of sonication amplitude on the microstructure and mechanical properties of AZ91E magnesium alloy

Journal of Magnesium and Alloys 2022年第12期10卷 3397-3405页

作者： P.Emadi B.Andilab c.ravindran centre for Near-net-shape Processing of Materials Ryerson University350 Victoria StreetTorontoON M5B 2K3 Canada

Light metals are gaining increased attention due to ecological sustainability concerns and strict emission regulations. Magnesium(Mg)is one such metal that has the potential to replace high density components, which can reduce emissions through lightweighting. However,the mechanical properties of Mg alloys must be improved for them to become viable candidates for structural applications. To this end, the current study examines the effect of sonication vibrational amplitude on the microstructure and mechanical properties of AZ91E Mg *** molten alloys were subjected to ultrasonic treatment at a frequency of 20 kHz, 180 s of processing time and vibrational amplitudes ranging from 1.25 to 15 μm. The resultant castings were characterized using optical microscopy, scanning electron microscopy and tensile testing. It was found that sonication with amplitudes up to 7.5 μm was able to effectively refine the secondary phases of the alloy. Similar trends were observed for grain size and yield strength. The refinement in microstructure was likely caused by the finer grain size and cavitation induced undercooling of the liquid metal. In addition, it was also noted that even the lowest level of amplitude(1.25 μm) was able to increase the density, improve the ultimate tensile strength and ductility of the castings. The tensile strength and ductility were thought to have been enhanced by ultrasonic degassing and refinement in microstructure, while the yield strength was improved through the Hall-Petch effect. The results from this study provided a basis for optimizing the sonication process and promoting its use in industry. As a result, Mg alloys improved through ultrasonic processing have the potential to replace higher density components, with consequent energy efficiency and environmental and ecological benefits.

关键词： Magnesium casting and solidification Ultrasonic processing Vibrational amplitude Grain refinement Mechanical properties

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combining machine learning with 3D-cFD modeling for optimizing a DISI engine performance during cold-start

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Energy and AI 2021年第3期5卷 298-315页

作者： Arun c.ravindran Sage L.Kokjohn Department of Mechanical Engineering University of Wisconsin-MadisonMadisonWI 53706USA

This work presents a methodology for using machine learning(ML)techniques in combination with 3D computa-tional fluid dynamics(cFD)modeling to optimize the cold-start fast-idle phase of a gasoline direct injection spark ignition(DISI)*** optimization process implies the identification of the range of operating parameters,that will ensure the following criteria under cold-start conditions:(1)a fixed IMEP of 2 bar(BMEP of 0 bar),(2)a stoichiometric exhaust equivalence ratio(based on carbon-to-oxygen atoms)to ensure the efficient operation of the after-treatment system,(3)enough exhaust heat flux to ensure a rapid light-offof the after-treatment system,and(4)reduced NOx and Hc emissions.A total of six operating parameters will be identified as having a signifi-cant influence on cold-start engine *** parameters are associated with the fuel injection strategy(end of the second injection,injection pressure,and fuel mass);combustion strategy(spark timing,spark energy);and intake airflow(intake manifold pressure).Performing an optimization study exclusively using multi-cycle(at least 3 cycles)3D cFD simulations would be an arduous *** example,to achieve an exhaust equivalence ratio of 1 and an IMEP of 2 bar,multiple iterations would be required for fuel mass(to account for film forma-tion),intake manifold pressure(to ensure enough air in-cylinder),and spark timing(to ensure the fixed load).This process would be more convoluted and expensive with the addition of constraints for exhaust heat flux and emissions.A promising approach to tackling such a complicated optimization process is to employ the concept of machine learning,which demands a database formed by the six operating parameters mentioned *** current work will demonstrate a strategy of combining cFD modeling with advanced Gaussian Process Regres-sion(GPR)-based ML models to make predictions about DISI cold-start behavior with acceptable accuracy and a substantially reduced computation

关键词： injection performance enough

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Non-alcoholic Fatty Liver Disease:A clinical Update

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Journal of clinical and Translational Hepatology 2017年第4期5卷 384-393页

作者： Joseph M Pappachan Shithu Babu Babu Krishnan nishal c.ravindran Department of Endocrinology Diabetes&MetabolismRoyal Lancaster InfirmaryUniversity Hospitals of Morecambe Bay NHS TrustLancasterUK Department of Medicine Dorset County HospitalDorchesterUK Department of Gastroenterology&Hepatology Royal Bournemouth HospitalBournemouthUK Department of Gastroenterology&Hepatology Hinchingbrooke HospitalHinchingbrookeHuntingdonUK

Non-alcoholic fatty liver disease(NAFLD)is currently the most common chronic liver disease in developed countries because of the obesity *** disease increases liverrelated morbidity and mortality,and often increases the risk for other comorbidities,such as type 2 diabetes and cardiovascular *** resistance related to metabolic syndrome is the main pathogenic trigger that,in association with adverse genetic,humoral,hormonal and lifestyle factors,precipitates development of *** markers and radiological imaging,along with liver biopsy in selected cases,help in diagnosis and *** lifestyle changes aiming at weight loss are the main therapeutic intervention to manage *** sensitizers,antioxidants,lipid lowering agents,incretin-based drugs,weight loss medications,bariatric surgery and liver transplantation may be necessary for management in some cases along with lifestyle *** review summarizes the latest evidence on the epidemiology,natural history,pathogenesis,diagnosis and management of NAFLD.

关键词： Nonalcoholic fatty liver disease(NAFLD) Nonalcoholic steatohepatitis NASH Insulin resistance Metabolic syndrome Lifestyle interventions Bariatric surgery

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Utilization of kinase inhibitors as novel therapeutic drug targets:A review

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Oncology Research 2022年第5期30卷 221-230页

作者： SUcHITRA nishal VIKAS JHAWAT SUMEET GUPTA PARMITA PHAUGAT Department of Pharmacy School of Medical and Allied SciencesGD Goenka UniversityGurugramIndia Department of Pharmaceutical Sciences Maharishi Markandeshwar(Deemed to be)UniversityMullanaAmbalaHaryanaIndia

Kinase inhibitors are a signiﬁcant and continuously developing division of target *** drug discovery and improvement efforts have examined numerous attempts to target the signaling pathway of *** Kinase inhibitors have been heralded as a game-changer in cancer *** developing kinase inhibitors as a treatment for various non-malignant disorders like auto-immune diseases,is currently undergoing extensive *** may be beneﬁcial to investigate whether cell-speciﬁc kinase inhibitor administration enhances therapeutic efﬁcacy and decreases adverse *** goal of the current review is to gain insight into the role of kinase inhibitors in facilitating effective target drug delivery for the treatment of various anti-inﬂammatory,auto-immune,and anticancer *** aim of this review is also to shed light on drug discovery approaches for kinase inhibitors,their mode of action,and delivery *** variation in the binding of kinases bestows different target approaches in drug design,which can be employed for designing the targeted *** target sites have been studied,exceeding the design of drugs for various diseases like cancer,Alzheimer’s,rheumatoid arthritis,*** delivery approaches have also been studied for the targeted application of kinase inhibitors.

关键词： Kinase inhibitors Targeted Drug designing Anti-cancer Auto-immune diseases

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Strain Limit of Extra Galvannealed Interstitial-Free and Bake Hardened Steel Sheets Under Different Stress conditions

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Journal of Iron and Steel Research International 2008年第5期15卷 56-60页

作者： R Narayanasamy N L Parthasarathi R ravindran c Sathiya Narayanan Department of Production Engineering National Institute of TechnologyTiruchirappalli 620015TamilnaduIndia

The formability of bake hardened steel （thickness 0.82 mm）, and the extra galvannealed IF steel （thickness 0.82 mm） have been studied. The suitability of the above steels for forming applications has been critically examined. The microstructure, tensile properties, and formability parameters of the above sheet metals were determined. The manufacturing process of the steels and the significance with reference to its formability were studied.

关键词： bake hardened steel extra galvannealed IF steel microstructure forming limit diagram tensile parameter

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calorie restriction potentiates epigallocatechin-3-gallate-mediated Nrf2 activation in hepatocytes of aged rats

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Asian Pacific Journal of Tropical Biomedicine 2023年第10期13卷 421-430页

作者： Rajeswari ravindran Malathi Manuel Thangarajeswari Mohan ravindran Jaganathan Kalaiselvi Periandavan Preclinical Department Faculty of MedicineUniversiti Kuala LumpurRoyal College of Medicine Perak30450IpohMalaysia Department of Medical Biochemistry Dr A.L Mudaliar Institute of Basic Medical SciencesUniversity of MadrasTaramaniChennai 600113India

Objective:To explore the combinatorial effect of epigallocatechin-3-gallate(EGcG)and calorie restriction on activation of nuclear factor erythroid 2-related factor 2(Nrf2),a transcription factor involved in the antioxidant defense system of aged ***:Aged male Wistar rats were calorie-restricted and treated with EGcG orally for 45 *** initial body weight of aged rats was recorded,and the final body weight was measured at the end of the experimental *** lipid and lipoprotein status,oxidative stress markers such as free radicals and malondialdehyde levels,and reduced glutathione were *** addition,RT-PcR and Western blotting analyses were ***:calorie restriction potentiated the effect of EGcG on enhancing antioxidant status,improving the levels of serum lipid and lipoproteins,upregulating Nrf2 and Bcl2,and downregulating Keap1,cullin3,Bax and cytochrome c in aged ***:calorie restriction can promote EGcG-mediated Nrf2 activation in aged *** preliminary finding paves the way for a combinatory approach to replenishing the antioxidant status during aging,thereby reducing the risk for age-associated degenerative diseases.

关键词： Aging Reactive oxygen species calorie restriction EGcG Nrf2 Antioxidant

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Management of inflammatory bowel disease in the pregnant patient

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World Journal of Gastroenterology 2008年第9期14卷 1326-1332页

作者： Flavio M Habal Nikila c.ravindran Department of Medicine Division of Gastro-enterology University Health NetworkToronto General Hospital SiteTorontoOntario M5G 2C4Canada Faculty of Medicine University of TorontoTorontoOntarioCanada

Inflammatory bowel disease (IBD) is a chronic disorder affecting young adults in their reproductive years. Many young women with IBD express concern about the effect their disease will have on fertility, pregnancy course and fetal development. This article presents an approach to management of IBD in the pregnant patient, including counseling and investigation, and summarizes existing data on the safety of medications used to treat IBD in pregnancy and breastfeeding.

关键词： Inflammatory bowel disease Ulcerative colitis crohn's disease Fertility Pregnancy Breast feeding

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Free radical scavenging potential and HPTLc analysis of Indigofera tinctoria linn(Fabaceae)

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Journal of Pharmaceutical Analysis 2016年第2期6卷 125-131页

作者： Sakthivel Srinivasan Wankupar Wankhar Sheeladevi Rathinasamy ravindran Rajan Department of Physiology Dr.ALM PG Institute of Basic Medical Sciences University of Madras

The objective of this study was to evaluate the free radical scavenging potential and high performance thin layer chromatography （HPTLc） fingerprinting of Indigofem tinctoria （I. tinctoria）, Phytochemical analysis was carried out using standard methods, and free radical scavenging activity of the plant was determined using 2,2-diphenyl-l-picrylhydrazy （DPPH）, nitric oxide （NO） and superoxide anion （O2-） radical scavenging capacities. HPTLc plate was kept in cAMAG TLc Scanner 3 and the Rf values at fin- gerprint data were recorded by WlNcATS software, Aqueous extract of I. tinctoria reliably showed the total phenolics （267.2 ± 2.42 mg/g）, flavonoids （75.43 ± 3.36 mg/g） and antioxidants （349.11 ±8.04 mg/g）. The extract was found to have DPPH （52.08%）, NO （23.12%） and 02 （26.79%） scavenging activities at the concentration of 250 pg/mL and the results were statistically significant compared with ascorbic acid standard （p 〈 0.05）. HPTLc results confirmed that the extract contained several potential active com- ponents such as phenols, flavonoids, saponins and terpenoids as the slides revealed multi-colored bands of varying intensities. This study confirmed that the plant had multipotential antioxidant and free ra- dicals scavenging activities.

关键词： Medicinal plants Indigofera tinctoria Antioxidants HPTLc

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XPc Lys939Gln polymorphism, smoking and risk of sporadic colorectal cancer among Malaysians

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World Journal of Gastroenterology 2013年第23期19卷 3623-3628页

作者： Abdul Aziz Ahmad Aizat Mohd Shahpudin Siti Nurfatimah Mustapha Mohd Aminudin ravindran Ankathil Human Genome centre School of Medical SciencesUniversiti Sains Malaysia Health Campus16150 Kubang Kerian Kelantan Malaysia

AIM: To investigate the risk association of xeroderma pigmentosum group c (XPc ) Lys939Gln polymorphism alone and in combination with cigarette smoking on colorectal cancer (cRc) predisposition. METHODS: Peripheral blood samples of 510 study subjects (255 cRc patients, 255 controls)were collected. DNA was extracted and genotyping was performed using polymerase chain reaction-restriction fragment length polymorphism. The association between polymorphic genotype and cRc predisposition was determined using the OR and 95%cI. RESULTS: The frequency of the homozygous variant (Gln/Gln) genotype was significantly higher in cases compared with controls (16.0% vs 10.2%, P = 0.049). The Gln/Gln genotype of XPc showed a significantly higher association with the risk of cRc (OR = 1.884; 95%cI: 1.082-3.277; P = 0.025). In the case of allele frequencies, variant allele c was associated with a significantly increased risk of cRc (OR = 1.375; 95%cI: 1.050-1.802; P = 0.020). Moreover, the risk was markedly higher for those who were carriers of the Gln/Gln variant genotype and were also cigarette smokers (OR = 3.409; 95%cI: 1.061-10.949; P = 0.032). cONcLUSION: The XPc Gln/Gln genotype alone and in combination with smoking increases the risk of cRc among Malaysians.

关键词： DNA repair Xeroderma pigmentosum group c Lys939Gln polymorphism cigarette smoking colorectal cancer Susceptibility risk

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Effect of Treatment for cHc on Liver Disease Progression and Hepatocellular carcinoma Development in African Americans

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Journal of clinical and Translational Hepatology 2015年第3期3卷 163-168页

作者： Naveen Reddy Paul Naylor Zaher Hakim Redwan Asbahi Karthik ravindran Elizabeth May Murray Ehrinpreis Milton Mutchnick Department of Internal Medicine/Division of Gastroenterology Wayne State University School of MedicineHarper University Hospital Detroit MI USA

Background and Aims:African Americans (AA) historically have a low response rate to hepatitis c therapies,and there is limited information available for this patient population regarding the development and treatment of chronic hepatitis c (cHc).The aim of this study was to evaluate liver disease progression and hepatocellular carcinoma (Hcc) development in AA with ***:Between 1995 and 2008,246 AA patients with cHc were identified from a database of patients and followed until 2012-2013 (average 8 years)or the development of Hcc after ***:Viral clearance (intent to treat;sustained virus response (SVR)) was achieved in 15% of patients with interferon based therapies with or without *** patients who achieved an SVR (n=22) did not develop Hcc or new onset cirrhosis,whereas the Hcc incidence in untreated AA patients was 23% (51/203).Patients who achieved an SVR also had improved fibrosis,as defined by the AST Platelet Ratio Index (APRI) and Fibrosis-4 (FIB-4) score,relative to nonresponders and untreated ***:The severity of liver disease at the first visit (except for cirrhosis) correlated with the development of Hcc,but because of the overlap in values between patients,these measurements were not useful for predicting individual *** cirrhosis at the first visit was not a predictive factor,treatment with newer antiviral therapies is the best option for reducing the incidence of advanced liver disease and its harmful outcomes in the AA population.

关键词： Hepatitis c cirrhosis Hepatocellular carcinoma APRI Fib-4

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