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Bioactivity enhancement by Sr doped Zn-Ca-P coatings on biomedical magnesium alloy

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Journal of Magnesium and Alloys 2019年第4期7卷 584-596页

作者： P.Amaravathy T.S.sampath kumar Medical Materials Laboratory Department of Metallurgical and Materials EngineeringIndian Institute of Technology MadrasChennai 600036India

The effect of strontium doped Zn-Ca-P(ZCP)coating by chemical conversion technique on the biodegradation of AZ31 alloy was *** coating formed with 1.5 wt.%Sr and 20 min phosphating time at 50℃ with pH 2.5 completely covers the alloy *** Sr doped coated sample also showed very low evolved hydrogen gas and pH change than the ZCP coatings suggested that the degradation of the alloy was extremely *** in vitro bioactivity studies in simulated body fluid exhibits deposition of calcium phosphate phases with Ca/P ratio of 1.55 which is close to that of hydroxyapatite,mineral component of *** evaluation with L929 cells showed higher cell viability of the Sr doped coatings compared to ZCP coatings.

关键词： Magnesium alloy Zinc calcium phosphate Biocompatibility Corrosion Strontium Cell viability

Ileocecal valve dysfunction in small intestinal bacterial overgrowth: A pilot study

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World Journal of Gastroenterology 2012年第46期18卷 6801-6808页

作者： Larry S Miller Anil k Vegesna Aiswerya Madanam sampath Shital Prabhu Sesha krishna kotapati kian Makipour Department of Medicine Section of Gastroenterology Hofstra Northshore Long Island Jewish Hospital School of Medicine at Hofstra University Department of Medicine Section of Gastroenterology Temple University Hospital

AIM: To explore whether patients with a defective ileocecal valve (ICV)/cecal distension reflex have small intestinal bacterial overgrowth. METHODS: Using a colonoscope, under conscious sedation, the ICV was intubated and the colonoscope was placed within the terminal ileum (TI). A manometry catheter with 4 pressure channels, spaced 1 cm apart, was passed through the biopsy channel of the colonoscope into the TI. The colonoscope was slowly withdrawn from the TI while the manometry catheter was advanced. The catheter was placed across the ICV so that at least one pressure port was within the TI, ICV and the cecum respectively. Pressures were continuously measured during air insufflation into the cecum, under direct endoscopic visualization, in 19 volunteers. Air was insufflated to a maximum of 40 mmHg to prevent barotrauma. All subjects underwent lactulose breath testing one month after the colonoscopy. The results of the breath tests were compared with the results of the pressures within the ICV during air insufflation. RESULTS: Nineteen subjects underwent colonoscopy with measurements of the ICV pressures after intubation of the ICV with a colonoscope. Initial baseline readings showed no statistical difference in the pressures of the TI and ICV, between subjects with positive lactulose breath tests and normal lactulose breath tests. The average peak ICV pressure during air insufflation into the cecum in subjects with normal lactu-lose breath tests was significantly higher than cecal pressures during air insufflation (49.33 ± 7.99 mmHg vs 16.40 ± 2.14 mmHg, P = 0.0011). The average percentage difference of the area under the pressure curve of the ICV from the cecum during air insufflations in subjects with normal lactulose breath tests was significantly higher (280.72% ± 43.29% vs 100% ± 0%, P = 0.0006). The average peak ICV pressure during air insufflation into the cecum in subjects with positive lactulose breath tests was not significantly different than cecal pre

关键词：肠细菌试验生长过度盲肠扩张压力范围注气过程毫米汞柱

Investigations of a nanostructured FeMnSi shape memory alloy produced via severe plastic deformation

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International Journal of Minerals,Metallurgy and Materials 2016年第11期23卷 1315-1322页

作者： Gheorghe Gurau Carmela Gurau Vedamanickam sampath Leandru Gheorghe Bujoreanu Faculty of Engineering "Dun?rea de Jos" University of Galati Department of Metallurgical and Materials Engineering Indian Institute of Technology Madras Faculty of Materials Science and Engineering "Gheorghe Asachi" Technical University of Ia?i

Low-cost iron-based shape memory alloys（SMAs） show great potential for engineering applications. The developments of new processing techniques have recently enabled the production of nanocrystalline materials with improved properties. These developments have opened avenues for newer applications for SMAs. The influence of severe plastic deformation induced by the high-speed high-pressure torsion（HSHPT） process on the microstructural evolution of an Fe–Mn–Si–Cr alloy was investigated. Transmission electron microscopic analysis of the alloy revealed the existence of nanoscale grains with an abundance of stacking faults. The high density of dislocations characteristic of severe plastic deformation was not observed in this alloy. X-ray diffraction studies revealed the presence of ε-martensite with an HCP crystal structure and γ-phase with an FCC structure.

关键词： iorn manganese silicon alloys shape memory effect nanostructured materials martensite plastic deformation

Study on performance of a packed bed latent heat thermal energy storage unit integrated with solar water heating system

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2006年第8期7卷 1422-1430页

作者： NALLUSAMY N sampath S. VELRAJ R. Department of Mechanical Engineering Sri Venkateswara College of Engineering Chennai 602 105 India Department of Automobile Engineering Sri Venkateswara College of Engineering Chennai 602 105 India Institute for Energy Studies College of Engineering Guindy Anna University Chennai 600 025 India

In thermal systems such as solar thermal and waste heat recovery systems, the available energy supply does not usually coincide in time with the process demand. Hence some form of thermal energy storage (TES) is necessary for the most effective utilization of the energy source. This study deals with the experimental evaluation of thermal performance of a packed bed latent heat TES unit integrated with solar flat plate collector. The TES unit contains paraffin as phase change material (PCM) filled in spherical capsules, which are packed in an insulated cylindrical storage tank. The water used as heat transfer fluid (HTF) to transfer heat from the solar collector to the storage tank also acts as sensible heat storage material. Charging experiments were carried out at varying inlet fluid temperatures to examine the effects of porosity and HTF flow rate on the storage unit performance. The performance parameters such as instantaneous heat stored, cumulative heat stored, charging rate and system efficiency are studied. Discharging experiments were carried out by both continuous and batchwise processes to recover the stored heat, and the results are presented.

关键词：换热流体装料卸料潜热相变材料填充床

Therapeutic effect of bone marrow mesenchymal stem cells on cold stress induced changes in the hippocampus of rats

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Neural Regeneration Research 2014年第19期9卷 1740-1744页

作者： Saravana kumar sampath kumar Saraswathi Perumal Vijayaraghavan Rajagopalan Department of Anatomy Saveetha Dental College Saveetha University ChennaiTamil NaduIndia

The present study aims to evaluate the effect of bone marrow mesenchymal stem cells on cold stress induced neuronal changes in hippocampal CA1 region of Wistar rats. Bone marrow mes- enchymal stem cells were isolated from a 6-week-old Wistar rat. Bone marrow from adult femora and tibia was collected and mesenchymal stem cells were cultured in minimal essential medium containing 10% heat-inactivated fetal bovine serum and were sub-cultured. Passage 3 cells were analyzed by flow cytometry for positive expression of CD44 and CD90 and negative expression of CD45. Once CD44 and CD90 positive expression was achieved, the cells were cultured again to 90% confluence for later experiments. Twenty-four rats aged 8 weeks old were randomly and evenly divided into normal control, cold water swim stress （cold stress）, cold stress ＋ PBS （intra- venous infusion）, and cold stress ＋ bone marrow mesenchymal stem cells （1 x 106; intravenous infusion） groups. The total period of study was 60 days which included 1 month stress period followed by 1 month treatment. Behavioral functional test was performed during the entire study period. After treatment, rats were sacrificed for histological studies. Treatment with bone marrow mesenchymal stem cells significantly increased the number of neuronal cells in hippocampal CA 1 region. Adult bone marrow mesenchymal stem cells injected by intravenous administration show potential therapeutic effects in cognitive decline associated with stress-related lesions.

关键词： nerve regeneration bone marrow mesenchymal stem cells hippocampus cold stress intravenous cognition neuronal cells CA1 region neural regeneration

Evaluation of different models to describe egg and pupal development of Xyleborus fornicatus Eichh, （Coleoptera： Scolytidae）, the shot-hole borer of tea in Sri Lanka

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Insect Science 2006年第2期13卷 109-118页

作者： RAVINDRA sampath WALGAMA MYRON PHILLIP ZALUCkI School of Integrative Biology University of Queensland Queensland Australia Division of Entomology Tea Research Institute Talawakelle Sri Lanka

Development data of eggs and pupae ofXyleborusfornicatus Eichh. （Coleoptera： Scolytidae）, the shot-hole borer of tea in Sri Lanka, at constant temperatures were used to evaluate a linear and seven nonlinear models for insect development. Model evaluation was based on fit to data （residual sum of squares and coefficient of determination or coefficient of nonlinear regression）, number of measurable parameters, the biological value of the fitted coefficients and accuracy in the estimation of thresholds. Of the nonlinear models, the Lactin model fitted experimental data well and along with the linear model, can be used to describe the temperature-dependent development of this species.

关键词： linear model nonlinear model insect development evaluation Xyleborus

Engineering microscale systems for fully autonomous intracellular neural interfaces

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Microsystems & Nanoengineering 2020年第1期6卷 1276-1295页

作者： Swathy sampath kumar Michael S.Baker Murat Okandan Jit Muthuswamy Biomedical Engineering School of Biological and Health Systems EngineeringArizona State UniversityTempeAZ 85287USA Mechanical Engineering Sandia National laboratoriesAlbuquerqueNMUSA mPower Technology Inc.AlbuquerqueNM 87102USA

Conventional electrodes and associated positioning systems for intracellular recording from single neurons in vitro and in vivo are large and bulky,which has largely limited their ***,acquiring successful intracellular recordings is very tedious,requiring a high degree of skill not readily achieved in a typical *** report here a robotic,MEMS-based intracellular recording system to overcome the above limitations associated with form factor,scalability,and highly skilled and tedious manual operations required for intracellular *** system combines three distinct technologies:(1)novel microscale,glass–polysilicon penetrating electrode for intracellular recording;(2)electrothermal microactuators for precise microscale movement of each electrode;and(3)closed-loop control algorithm for autonomous positioning of electrode inside single *** we demonstrate the novel,fully integrated system of glass–polysilicon microelectrode,microscale actuators,and controller for autonomous intracellular recordings from single neurons in the abdominal ganglion of Aplysia californica(n=5 cells).Consistent resting potentials(60 mV)were recorded after each successful penetration attempt with the controller and microactuated glass–polysilicon *** success rate of penetration and quality of intracellular recordings achieved using electrothermal microactuators were comparable to that of conventional positioning *** data from in vivo experiments in anesthetized rats show successful intracellular *** MEMS-based system offers significant advantages:(1)reduction in overall size for potential use in behaving animals,(2)scalable approach to potentially realize multi-channel recordings,and(3)a viable method to fully automate measurement of intracellular *** system will be evaluated in vivo in future rodent studies.

关键词： recording electrode system

Molecular recognition and specificity of biomolecules to titanium dioxide from molecular dynamics simulations

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npj Computational Materials 2020年第1期6卷 1390-1397页

作者： Janani sampath Andrew kullman Rachel Gebhart Gary Drobny Jim Pfaendtner Physical Sciences Division Pacific Northwest National LaboratoryRichlandWAUSA Department of Chemical Engineering University of WashingtonSeattleWAUSA Department of Chemistry University of WashingtonSeattleWAUSA

Titania(TiO_(2))is used extensively in biomedical applications;efforts to boost the biocompatibility of TiO_(2) include coating it with the titania binding hexamer,*** understand the binding mechanism of this peptide,we employ molecular dynamics simulations enhanced by metadynamics to study three amino acids present in the peptide—arginine(R),lysine(k),and aspartate(D),on four TiO2 variants that have different degrees of surface hydroxyl groups.

关键词： dynamics titanium dioxide

GIS-Based Situational Analysis of Cutaneous Leishmaniasis Disease (CLD) in Sri Lanka

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Journal of Geoscience and Environment Protection 2023年第3期11卷 70-86页

作者： sampath Arunashantha Mangala Jayarathne Saseeka Wijesekera Nishan Sakalasooriya Charuni kottage Department of Geography University of Kelaniya Kelaniya Sri Lanka Regional Health Services Office Polonnaruwa Sri Lanka

Cutaneous Leishmaniasis (CL) is a severe health problem and a parasitic disease on human dermal and widely pervades tropical and subtropical developing counties. The study is mainly focused on Geographic Information System (GIS) based Situational Analysis (SA). The clinically recorded 394 CL patients’ information was obtained from the District General Hospital of Polonnaruwa (DGHP) for 2017 and 2018. The spatial distribution of these patients was collected using Global Positing System (GPS). Moran’s I Index spatial autocorrelation technique and Getis-Ord Gi were used to identify the study site’s hot spot and cold spot areas. More than 75% of the CL patients’ population were highly involved with agricultural activities, and they are the highly exposed group of the CL in the study area. Also, 75% of the CL population were men, and the highly vulnerable age group was 35 - 39 men and 40 - 44 women. The generated Moran’s I Index indicates 0.0321, representing a randomly distributed pattern of CL patients over the District, and the Getis-Ord Gi Z Score value was >1.96 (p ks earlier than the reported month. Hence to prevent the disease spread, it is essential to implement an awareness program regarding sandflies’ behaviour and CLD.

关键词： Sandflies Disease Geoinformatics Techniques Environmental Factors Dry Zone