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Cilia-assisted hydromagnetic pumping of biorheological couple stress fluids

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Propulsion and Power Research 2019年第3期8卷 221-233页

作者： K.Ramesh D.tripathi O.Anwar Bég Department of Mathematics Symbiosis Institute of TechnologySymbiosis International UniversityPune412115India Department of Mechanical Engineering Manipal University JaipurRajasthan303007India Fluid Mechanics/Propulsion Aeronautical/Mechanical Engineering DepartmentSalford UniversityManchesterUK

A theoretical study is conducted for magnetohydrodynamic pumping of electroconductive couple stress physiological liquids(***)through a two-dimensional ciliated channel.A geometric model is employed for the cilia which are distributed at equal intervals and produce a whip-like motion under fluid interaction which obeys an elliptic trajectory.A metachronal wave is mobilized by the synchronous beating of cilia and the direction of wave propagation is parallel to the direction of fluid flow.A transverse static magnetic field is imposed transverse to the channel *** Stokes’couple stress(polar)rheological model is utilized to characterize the *** normalized two-dimensional conservation equations for mass,longitudinal and transverse momentum are reduced with lubrication approximations(long wavelength and low Reynolds number assumptions)and feature a fourth order linear derivative in axial velocity representing couple stress contribution.A coordinate transformation is employed to map the unsteady problem from the wave laboratory frame to a steady problem in the wave *** slip conditions are imposed at the channel *** emerging linearized boundary value problem is solved analytically and expressions presented for axial(longitudinal)velocity,volumetric flow rate,shear stress function and pressure *** flow is effectively controlled by three geometric parameters,viz cilia eccentricity parameter,wave number and cilia length and two physical parameters,namely magnetohydrodynamic(MHD)body force parameter and couple stress non-Newtonian *** solutions are numerically evaluated with MATLAB *** velocity is observed to be enhanced in the core region with greater wave number whereas it is suppressed markedly with increasing cilia length,couple stress and magnetic parameters,with significant flattening of profiles with the latter two *** pressure gradient is decreased with eccentricity parameter whereas it is ele

关键词： Magneto hydrodynamics Metachronal waves Cilia Synchronous beating Polar couple stress fluid Physiological transport Magnetic blood pumps

Dose-dependent effect of histamine on antibody generation in vivo

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Asian Pacific Journal of Tropical Medicine 2010年第2期3卷 112-116页

作者： tripathi T Shahid M Khan HM Khan RA Siddiqui MU DePartment of Biochemistry Faculty of MedicineJawaharlal Nehru Medical College and HospitalAligarh Muslim University Department of Microbiology Faculty of MedicineJawaharlal Nehru Medical College and HospitalAligarh Muslim University Department of Pharmacology Faculty of MedicineJawaharlal Nehru Medical College and HospitalAligarh Muslim University Department of Biochemistry Faculty of MedicineJawaharlal Nehru Medical College and HospitalAligarh Muslim University

Objective:To delineate immunomodulatory role of histamine on antibody generation pr of ile in rabbit in the present dose-dependent histamine ***:The cohort comprised of three groups(Ⅲ,ⅣandⅤ),containing six rabbits each,and received subcutaneous histamine 50μg/kg×bis in die(b.i.d.),100μg/kg×*** 200μg/kg X b.i.d.,respectively for 10 days (starting from the 1st day).They were subsequently immunized on the 3rd day with intravenous injection of sheep blood cell(SRBC)(1×10 cells/mL).GroupⅡ(positive control)(n=6) received vehicle(sterile distilled water) and immunized at day 3 similarly while groupⅠ(negative control) (n=6) remained non-immunized and received only *** experimentations were performed in *** samples were collected on pre-immunization(pre-I)(day 0),as well as on days 7-,14-,21-,28- and 58- post-immunization(post-I).Immunological parameters[total immunoglobulins(Igs),IgM and IgG]were analyzed by enzyme linked immunosorbent assay (ELISA) ***:Histamine could influence a detectable antibody response to SRBC as early as day 7-post-I,which lasted until day 58- *** results were found statistically significant(P< 0.05).Conclusions:Our results provide evidence that histamine has a short-term effect on antibody generation(until its presence in the body),and the antibody generation titer in vivo were affected by the concentration of histamine.

关键词： Histamine Immumomodulation T-cell dependent antibody response Humoral immune response SRBC

Field cancerisation in colorectal cancer:A new frontier or pastures past?

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World Journal of Gastroenterology 2015年第13期21卷 3763-3772页

作者： Abhilasha Patel Gyanendra tripathi Kishore Gopalakrishnan Nigel Williams Ramesh P Arasaradnam Department of Colorectal Surgery University Hospitals of Coventry and Warwickshire NHS TrustCoventry CV2 2DXUnited Kingdom University of Warwick Coventry CV4 7ALUnited Kingdom Department of Pathology University Hospitals of Coventry and Warwickshire NHS TrustCoventry CV2 2DXUnited Kingdom

Despite considerable advances in our understanding of cancer biology, early diagnosis of colorectal cancer remains elusive. Based on the adenoma-carcinoma sequence, cancer develops through the progressive accumulation of mutations in key genes that regulate cell growth. However, recent mathematical modelling suggests that some of these genetic events occur prior to the development of any discernible histological abnormality. Cells acquire pro-tumourigenic mutations that are not able to produce morphological change but predispose to cancer formation. These cells can grow to form large patches of mucosa from which a cancer arises. This process has been termed "field cancerisation". It has received little attention in the scientific literature until recently. Several studies have now demonstrated cellular, genetic and epigenetic alterations in the macroscopically normal mucosa of colorectal cancer patients. In some reports, these changes were effectively utilised to identify patients with a neoplastic lesion suggesting potential application in the clinical setting. In this article, we present the scientific evidence to support field cancerisation in colorectal cancer and discuss important limitations that require further investigation. Characterisation of the field defect is necessary to enable early diagnosis of colorectal cancer and identify molecular targets for chemoprevention. Field cancerisation offers a promising prospect for experimental cancer research and has potential to improve patient outcomes in the clinical setting.

关键词： Colorectal cancer Carcinogenesis Biomarkers Epigen

Analytical approach to entropy generation and heat transfer in CNT-nanofluid dynamics through a ciliated porous medium

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Journal of Hydrodynamics 2018年第2期30卷 296-306页

作者： Noreen Sher Akbar M.Shoaib Dharmendra tripathi Shashi Bhushan O.Anwar Bég DBS&H CEME National University of Sciences and Technology School of Natural Sciences National University of Sciences and Technology Department of Mechanical Engineering Manipal University Medical Energy and Propulsion Engineering Sciences Department of Aeronautical and Mechanical Engineering University of Salford

The transportation of biological and industrial nanofluids by natural propulsion like cilia movement and self-generated contraction-relaxation of flexible walls has significant applications in numerous emerging technologies. Inspired by multi-disciplinary progress and innovation in this direction, a thermo-fluid mechanical model is proposed to study the entropy generation and convective heat transfer of nanofluids fabricated by the dispersion of single-wall carbon nanotubes（SWCNT） nanoparticles in water as the base fluid. The regime studied comprises heat transfer and steady, viscous, incompressible flow, induced by metachronal wave propulsion due to beating cilia, through a cylindrical tube containing a sparse（i.e., high permeability） homogenous porous medium. The flow is of the creeping type and is restricted under the low Reynolds number and long wavelength approximations. Slip effects at the wall are incorporated and the generalized Darcy drag-force model is utilized to mimic porous media effects. Cilia boundary conditions for velocity components are employed to determine analytical solutions to the resulting non-dimensionalized boundary value problem. The influence of pertinent physical parameters on temperature, axial velocity, pressure rise and pressure gradient, entropy generation function, Bejan number and stream-line distributions are computed numerically. A comparative study between SWCNT-nanofluids and pure water is also computed. The computations demonstrate that axial flow is accelerated with increasing slip parameter and Darcy number and is greater for SWCNT-nanofluids than for pure water. Furthermore the size of the bolus for SWCNT-nanofluids is larger than that of the pure water. The study is applicable in designing and fabricating nanoscale and microfluidics devices, artificial cilia and biomimetic micro-pumps.

关键词： Metachronal wave single-wall carbon nanotubes (SWCNT) entropy generation porous medium cilia motion heat transfer Bejan number

Intra-day variability of three Seyfert galaxies measured with XMM-Newton

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Research in Astronomy and Astrophysics 2019年第8期19卷 31-44页

作者： Ashutosh tripathi Paul Joseph Wiita Alok Chandra Gupta Min-Feng Gu Mai Liao Center for Field Theory and Particle Physics and Department of Physics Fudan UniversityShanghai200433China Department of Physics The College of New JerseyP.O.Box7718EwingNJ08628-0718USA Kavli Institute for Particle Physics and Cosmology SLAC2575Sand Hill Rd.Menlo ParkCA94025USA Aryabhatta Research Institute of Observational Sciences(ARIES) Manora PeakNainital-263002India Key Laboratory for Research in Galaxies and Cosmology Shanghai Astronomical ObservatoryChinese Academy ofSciencesShanghai200030China University of Chinese Academy of Sciences Beijing100049China

We present and analyze the variability of three Seyfert galaxies on intra-day timescales. We have analyzed in a uniform manner the 38 longest(> 30 ks) observations made for NGC 4051, MCG-06–30–15 and NGC 4151 by XMM-Newton between 2000 and 2015. The nuclei were quite active during essentially all of these observations and the overall X-ray fluxes(0.3–10 keV) varied by an order of magnitude. Most of the observations do appear to show characteristic timescales, estimated through their auto-correlation functions, ranging between ~2.9 ks and ~45.3 ks. The hard(2–10 keV) and soft(0.3–2.0 keV) bands are very well correlated but consideration of their hardness ratios shows that the sources typically soften during flares. We also provide new estimates of the central black hole masses for these three AGNs that support the hypothesis that Narrow Line Seyfert 1 galaxies have relatively small central black holes.

关键词： galaxies:active narrow line Seyfert 1 galaxy (NLSy1):general NLSy1:individual NLSy1:individual:NGC 4051

Room-temperature lasing from nanophotonic topological cavities

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Light(Science & Applications) 2020年第1期9卷 823-830页

作者： Daria Smirnova Aditya tripathi Sergey Kruk Min-Soo Hwang Ha-Reem Kim Hong-Gyu Park Yuri Kivshar Nonlinear Physics Center Research School of PhysicsAustralian National UniversityCanberraACT 2601Australia Institute of Applied Physics Russian Academy of ScienceNizhny Novgorod 603950Russia Department of Physics Indian Institute of TechnologyDelhi 110016India Department of Physics Korea UniversitySeoul 02841Republic of Korea

The study of topological phases of light underpins a promising paradigm for engineering disorder-immune compact photonic devices with unusual *** with an optical gain,topological photonic structures provide a novel platform for micro-and nanoscale lasers,which could benefit from nontrivial band topology and spatially localized gap ***,we propose and demonstrate experimentally active nanophotonic topological cavities incorporating Ⅲ-Ⅴ semiconductor quantum wells as a gain medium in the *** observe room-temperature lasing with a narrow spectrum,high coherence,and threshold *** emitted beam hosts a singularity encoded by a triade cavity mode that resides in the bandgap of two interfaced valley-Hall periodic photonic lattices with opposite parity *** findings make a step towards topologically controlled ultrasmall light sources with nontrivial radiation characteristics.

关键词： lasing singularity narrow

Rainforests north of the Tropic of Cancer: Physiognomy, floristics and diversity in ‘lowland rainforests’ of Meghalaya, India

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Plant Diversity 2017年第1期39卷 20-36页

作者： Uma Shankar Amit Kumar tripathi Department of Botany North-Eastern Hill University Shillong 793 022 India

The lowland rainforests of Meghalaya, India represent the westernmost limit of the rainforests north of the Tropic of Cancer. These forests, on the Shillong plateau, are akin to Whitmore's ‘tropical lowland evergreen rainforest' formation and exhibit striking similarities and conspicuous differences with the equatorial rainforests in Asia-Pacific as well as tropical seasonal rainforests in southwestern China near the Tropic of Cancer. We found these common attributes of the rainforests in Meghalaya: familial composition with predominance of Euphorbiaceae, Lauraceae, Meliaceae, Moraceae, Myrsiticaceae,Myrtaceae and Rubiaceae; deciduousness in evergreen physiognomy; dominance of mega-and mesophanerophytic life-forms; abundance of species with low frequency of occurrence(rare and aggregated species); low proportional abundance of the abundant species; and truncated lognormal abundance distribution. The levels of stand density and stand basal area were comparable with seasonal rainforests in southwestern China, but were lower than equatorial rainforests. Tropical Asian species predominated flora, commanding 95% of the abundance. The differences include overall low stature(height) of the forest, inconspicuous stratification in canopy, fewer species and individuals of liana, thicker understory,higher proportion of rare species, absence of locally endemic species and relatively greater dominance of Fagaceae and Theaceae. The richness of species per hectare(S) was considerably lower at higher latitudes in Meghalaya than in equatorial rainforests, but was comparable with seasonal rainforests. Shannon's diversity index(H’=4.40 nats for ≥10 cm gbh and 4.25 nats for ≥30 cm gbh) was lower on higher latitudes in Meghalaya in comparison to species-rich equatorial rainforests, but it was the highest among all lowland rainforests near the Tropic of Cancer.

关键词： Lowland rainforest Forest structure Floristics Phytosociology Species richness Life-form spectrum

chemistry and bioactivities of essential oils of some Ocimum species:an overview

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Asian Pacific Journal of Tropical Biomedicine 2014年第9期4卷 682-694页

作者： Abhay Kumar Pandey Pooja Singh Nijendra Nath tripathi Bacteriology and Natural Pesticide Laboratory Department of BotanyDDU Gorakhpur University

Essential oils of different species of the genus Ocimum are natural flavouring materials of commercial *** data given in current literature are pertaining to the chemical composition of essential oils of different Ocimum species viz.,Ocimum basilicum Linn.(*** basilicum ***,Ocimum basilicum ***).Ocimum campechianum Mill.,Ocimum canum Sims.(Ocimum americanum),Ocimum citriodorum,Ocimum gratissimum Linn.,Ocimum kilimandscharicum Linn..Ocimum micranthum Willd.,Ocimum sanctum Linn.,(*** tenuiflorum Linn.),Ocimum selloi Benth..Ocimum trichodon,Ocimum utricifolium from different geographical regions.A considerable difference in chemical composition of a particular species is found,which may be due to their occurrence in different eco-climatic zones and changes in edaphic *** is also focused on the biological properties of Ocimum oils which are related to their various interesting applications as antimicrobial,antioxidant,repellent,insecticidal,larvieidal,nematicidal and therapeutic(anti-inflammatory,antinociceptive,antipyretic,antiulcer,analgesic,anthelmintic,anticarcinogenic,skin permeation enhancer,immunomodulatory,cardio-protective,antilipidemic) agents.

关键词： Ocimum species Essential oil Chemistry Biological properties

Microstructure and texture evolution in AZ31 magnesium alloy during caliber rolling at different temperatures

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Journal of Magnesium and Alloys 2017年第3期5卷 340-347页

作者： Abhishek tripathi S.V.S.Narayana Murty P.Ramesh Narayanan Department of Metallurgical Engineering and Materials Science Indian Institute of Technology BombayMumbai 400076India Materials Characterisation Division Materials and Metallurgy GroupVikram Sarabhai Space CentreTrivandrum 695022India

Magnesium alloy AZ31 was caliber rolled at different temperatures viz.523K,573K,623K,673K and 723K imposing a total cumulative reduction of 92%and a cumulative strain of *** associated microstructure and texture evolution were studied using Electron Back Scattered Diffraction(EBSD)and X-ray macro-texture observations *** refinement was observed in all the caliber rolled bars indicating the occurrence of dynamic *** parameter and texture index were used to study the evolution of *** doubling of the yield strength at room temperature was observed by caliber rolling at a temperature of *** improvement in mechanical properties was explained on the basis of the fine grain microstructures and suitable development of crystallographic *** on the present study,warm caliber rolling can be used as a good production method for obtaining long bars of high strength magnesium alloy AZ31.

关键词： Magnesium alloy AZ31 Microstructure Caliber rolling Texture