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CARBON NITRIDE FILMS PREPARED AT DIFFERENT N_2/Ar RATIOS BY CLOSED FIELD UNBALANCED REACTIVE MAGNETRON SPUTTERING

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Acta Metallurgica Sinica(English Letters) 2005年第3期18卷 280-288页

作者： A. vyas Department of Manufacturing Engineering and Engineering Management (MEEM) City University of Hong Kong Kowloon Hong Kong China

Carbon nitride (CNx) thin films have been deposited onto Si(100) (for structural and mechanical analyses) and M42 high-speed-steel (for tribological measurement s) substrates at room temperature by closed-field unbalanced magnetron sputterin g. The mechanical and tribological properties of these films were highly depende nt on the N/C concentration ratio that was adjusted by the F(N2)/F(Ar) flow-rate ratio at fixed substrate biasing of -60V during deposition. The films were char acterized by employing scanning electron microscopy (SEM), atomic force microsco py (AFM), nano-indentation measurements, X-ray photoelectron spectroscopy (XPS), Raman scattering and Fourier transform infrared (FTIR) spectroscopy, pin-on-dis c tribometer, scratch tester, and Rockwell-C tester. The results showed that the N content in the films increased with the N2 pressure. However, the maximum N/C ratio obtained was 0.25. The nanohardness was measured to be in the range of 11 .7-20.8GPa depending on the N/C ratios. The XPS N 1s spectra showed the existenc e of both N-C sp2 and N-C sp3 bonds in films. Raman and FTIR spectra exhibited t hat N-C bonds were fewer when compared to other N-C bonds. The friction coeffici ent of the film deposited onto steel substrate with N/C=0.26 was measured to be ~0.08 and for film with N/C=0.22 a high critical load of 70N was obtained. The t ribological data also showed that the wear rates of these films were in the rang e of ~10-16m3/Nm, indicating excellent wear resistance for CNx films.

关键词： carbon nitride X-ray photoelectron spectroscopy Raman spectroscop y pin-on disc wear test tribology

Fecal transplant policy and legislation

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World Journal of Gastroenterology 2015年第1期21卷 6-11页

作者： Dinesh vyas Apoorva Aekka Arpita vyas College of Human Medicine Michigan State UniversityEast LansingMI 48912United States Department of Pediatrics Heart Failure Research LabEast LansingMI 48912United States

Fecal microbiota transplantation(FMT) has garnered significant attention in recent years in the face of a reemerging Clostridium difficile(***) *** results from the first randomized control trial evaluating FMT have encouraged the medical community to explore the process further and expand its application beyond *** infections and even the gastrointestinal *** promising and numerous the prospects of FMT appear,the method remains limited in scope today due to several important barriers,most notably a poorly defined federal regulatory *** Food and Drug Administrationhas found it difficult to standardize and regulate the administration of inherently variable,metabolically active,and ubiquitously available fecal *** current cumbersome policy,which classifies human feces as a drug,has prevented physicians from providing FMT and deserving patients from accessing FMT in a timely fashion,and subsequent modifications seem only to be *** argument for reclassifying fecal material as human tissue is well ***,this would allow for a regulatory framework that is sufficiently flexible to expand access to care and facilitate research,but also appropriately restrictive and centralized to ensure patient *** an approach can facilitate the advancement of FMT to a more refined,controlled,and aesthetic process,perhaps in the form of a customized and wellcharacterized stool substitute therapy.

关键词： Stool therapy Clostridium difficile Fecal microbio

Harnessing the potential of gene editing technology using CRISPR in inflammatory bowel disease

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World Journal of Gastroenterology 2019年第18期25卷 2177-2187页

作者： Viktor Limanskiy Arpita vyas Lakshmi Shankar Chaturvedi Dinesh vyas Department of Surgery San Joaquin General Hospital College of Medicine CNSU College of Medicine and College of Pharmacy California Northstate University

The molecular scalpel of clustered regularly interspersed short palindromic repeats/CRISPR associated protein 9(CRISPR/Cas9) technology may be sharp enough to begin cutting the genes implicated in inflammatory bowel disease(IBD) and consequently decrease the 6.3 billion dollar annual financial healthcare burden in the treatment of IBD. For the past few years CRISPR technology has drastically revolutionized DNA engineering and biomedical research field. We are beginning to see its application in gene manipulation of sickle cell disease,human immunodeficiency virus resistant embryologic twin gene modification and IBD genes such as Gatm(Glycine amidinotransferase, mitochondrial),nucleotide-binding oligomerization domain-containing protein 2, KRT12 and other genes implicated in adaptive immune convergence pathways have been subjected to gene editing, however there are very few publications. Furthermore,since Crohn's disease and ulcerative colitis have shared disease susceptibility and share genetic gene profile, it is paramount and is more advantageous to use CRISPR technology to maximize impact. Although, currently CRISPR does have its limitations due to limited number of specific Cas enzymes, off-target activity,protospacer adjacent motifs and crossfire between different target sites. However,these limitations have given researchers further insight on how to augment and manipulate enzymes to enable precise gene excision and limit crossfire between target sites.

关键词： Clustered regularly interspersed short palindromic repeats Inflammatory bowel disease Crohn’s disease Ulcerative colitis Gene excision Gene editing Gene therapy Financial impact of inflammatory bowel disease on healthcare Clustered regularly interspersed short palindromic repeats crossfire

Nuclear factor kappa B role in inflammation associated gastrointestinal malignancies

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World Journal of Gastroenterology 2015年第11期21卷 3174-3183页

作者： Sahil Gambhir Dinesh vyas Michael Hollis Apporva Aekka Arpita vyas Department of Surgery College of Human MedicineMichigan State University Department of Pediatrics College of Human Medicine - Michigan State University

Nuclear factor kappa B(NF-κB) has an established role in the regulation of innate immunity and ***-κB is also involved in critical mechanisms connecting inflammation and cancer *** investigations suggest that the NF-κB signaling cascade may be the central mediator of gastrointestinal malignancies including esophageal,gastric and colorectal *** review will explore NF-κB's function in inflammation-associated gastrointestinal malignancies,highlighting its oncogenic contribution to each step of ***-κB's role in the inflammation-to-carcinoma sequence in gastrointestinal malignancies warrants stronger emphasis upon targeting this pathway in achieving greater therapeutic efficacy.

关键词： Gastrointestinal cancer Inflammation Nuclear facto

Stool therapy may become a preferred treatment of recurrent Clostridium difficile?

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World Journal of Gastroenterology 2013年第29期19卷 4635-4637页

作者： Dinesh vyas Heidi E L'Esperance Arpita vyas Department of Surgery College of Human Medicine Michigan State University East Lansing MI 48912 United States Department of Pediatrics College of Human Medicine Michigan State University East Lansing MI 48912 United States

Fecal enemas were first reported to successfully treat life threatening enterocolitis in 1958, but fecal therapy to treat Clostridium difficile (C. difficile ) infection has remained esoteric and not well investigated until recently. In the past few years, systematic reviews of case series and case reports of fecal microbiota transplant for recurrent C. difficile infection have become available and validate use of fecal transplant for C. difficile enterocolitis. Methods of fecal transplant reported in the literature include: nasogastric tube, gastroscope, duodenal tube, colonoscopy, rectal tube, and fecal enemas administered at home; no method has been shown to be superior. A recent randomized study published in New England Journal of Medicine found fecal transplant to be superior to oral vancomycin alone in treatment of recurrent C. difficile enterocolitis. The significance of this trial cannot be underestimated as it lends credibility to the idea of intentionally using microbes to combat disease, providing an alternative to the older paradigm of disease eradication through use of antimicrobials.

关键词： Clostridium difficile Enterocolitis Pseudomembranous Fecal transplantation Vancomycin

Insights on drug and gene delivery systems in liver fibrosis

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Asian Journal of Pharmaceutical Sciences 2023年第2期18卷 4-27页

作者： Kunj vyas Mayur M Patel Department of Pharmaceutics Institute of PharmacyNirma University SG HighwayGujarat 382481India

Complications of the liver are amongst the world’s worst *** fibrosis is the first stage of liver problems,while cirrhosis is the last stage,which can lead to *** creation of effective anti-fibrotic drug delivery methods appears critical due to the liver’s metabolic capacity for drugs and the presence of insurmountable physiological impediments in the way of *** breakthroughs in anti-fibrotic agents have substantially assisted in fibrosis;nevertheless,the working mechanism of anti-fibrotic medications is not fully understood,and there is a need to design delivery systems that are well-understood and can aid in ***-based delivery systems are regarded to be effective but they have not been adequately researched for liver *** a result,the capability of nanoparticles in hepatic delivery was *** approach is targeted drug delivery,which can considerably improve efficacy if delivery systems are designed to target hepatic stellate cells(HSCs).We have addressed numerous delivery strategies that target HSCs,which can eventually aid in *** genetics have proved to be useful,and methods for delivering genetic material to the target place have also been investigated where different techniques are *** summarize,this review paper sheds light on themost recent breakthroughs in drug and gene-based nano and targeted delivery systems that have lately shown useful for the treatment of liver fibrosis and cirrhosis.

关键词： Liver fibrosis Gene delivery system Nano drug delivery system Cirrhosis Targeted delivery system Vector

Effect of contrasting climates on antioxidant and bioactive constituents in five medicinal herbs in Western Himalayas

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Journal of Mountain Science 2016年第3期13卷 484-492页

作者： Tarandeep KAUR Rohini BHAT Dhiraj vyas Biodiversity and Applied Botany Division Indian Institute of Integrative Medicine(CSIR) Academy of Scientific and Innovative Research Indian Institute of Integrative Medicine (CSIR)

To understand the effect of climate change on constitutive antioxidant and biochemical metabolites in Western Himalayas, five medicinal herbs were selected and grown at two altitudes in Jammu(305 m) and Srinagar(1730 m) with subtropical and temperate climates, *** variations were observed in phenols and flavonoids in Hypericum perforatum L., Matricaria chamomilla L., Thymus vulgaris L., Cynara cardunculus L. and Echinacea purpurea L. growing at two locations. High altitude temperate site show variable(up to 13 fold) increase in their ***(1.3- 1.8 times), sugars(2.8- 4.1 times) and free amino acid(1.04- 1.22 times) were also higher at Srinagar(1730 m). Within these plants, *** and M. chamomilla have shown higher accumulation of phenols, xanthophylls and proline even at subtropical environment in Jammu(305 m)suggesting potential for increasing their geographical area. The results demonstrate that changing environmental conditions significantly affect the bioactive constituents, which accumulate as a defence strategy by these temperate plants. Their medicinal significance during climate change scenario has also been discussed.

关键词： Medicinal herbs Flavonoids Phenols Glutathione Western Himalayas Climate change

A Novel Application of Multi-Resonant Dissipative Elastic Metahousing for Bearings

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Acta Mechanica Solida Sinica 2021年第4期34卷 449-465页

作者： Muhammad C.W.Lim N.S.vyas Department of Architecture and Civil Engineering City University of Hong KongKowloonHong Kong SARChina Department of Mechanical Engineering Indian Institute of Technology KanpurKanpur208016India

Bearing as an important machine element is widely used for industrial and automotive *** certain operational speed,bearings induce disturbing vibrations and noises that affect machine service life,productivity and passenger comfort in case of vehicle *** elastic metamaterials have caught considerable attention of scientific community due to their effective medium properties and peculiar dynamic characteristics including frequency bandgaps that can be effectively applied to attenuate and control undesirable vibration and *** a substantial amount of theoretical work for effective medium characteristics and dynamic properties of acoustic/elastic metamaterials has been reported,the practical design and application of these composite structures for real-life engineering problems still remain *** present study intends to investigate a potential application of dissipative elastic metamaterials in controlling the bearing-generated vibration and noises over an ultrawide frequency *** study is based on a simple analytical model together with rigorous finite element numerical *** has been established that the dissipative characteristic of resonant system caused by larger material mismatch broadens the local resonance bandgaps beyond the bounding resonance frequency at the cost of wave *** order to achieve broadband vibration and noise control,multi-resonant composite structures are embedded inside the bearing housing in five different *** reported results revealed the presence of broadband wave attenuation zone distributed from 3 to 52 kHz with consideration of material *** bearing-generated vibration and noises lying inside the wave attenuation zone will be *** feasibility study provides a new concept for the design and application of acoustic/elastic metamaterials in the bearing industry to improve machine service life and to enhance productivity and passenger comfo

关键词： Bearing metahousing Dissipative elastic metamaterials Frequency Local resonance bandgap Vibration attenuation zone

Screening colonoscopy:The present and the future

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World Journal of Gastroenterology 2021年第3期27卷 233-239页

作者： Chelsea V Hayman Dinesh vyas College of Medicine California Northstate UniversityElk GroveCA 95757United States Department of Surgery San Joaquin General HospitalFrench CampCA 95231United States

In the United States,colorectal cancer(CRC)is the second leading cause of mortality in men and *** are now seeing an increasing number of patients with advanced-stage diagnosis and mortality from colorectal cancer before 50 years of age,which requires earlier *** the increasing need for CRC screening through colonoscopy,and thus endoscopists,easier and simpler techniques are needed to train proficient *** most widely used approach by endoscopists is air insufflation colonoscopy,where air distends the colon to allow visualization of the colonic *** technique is uncomfortable for patients and requires an anesthetist to administer *** addition,patients commonly complain about discomfort post-op as air escapes into the small bowel and cannot be adequately *** research into the use of water insufflation colonoscopies has proved promising in reducing the need for sedation,decreasing discomfort,and increasing the visibility of the colonic *** direction into water insufflation colonoscopies which have shown to be simpler and easier to teach may increase the number of proficient endoscopists in training to serve our aging population.

关键词： Colorectal cancer Water-insufflation colonoscopy Air-insufflation colonoscopy Adenomatous polyps Adenoma detection rate