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Superconductivity 2023年第4期8卷 79-83页

作者： Doyel Rakshit sourav das Ajay Kumar Ghosh Department of Physics Jadavpur UniversityKolkata 700032India

Resistances of grain junctions of bulk polycrystalline YBa_(2)Cu_(3)O_(7−δ)(YBCO) and DyBa_(2)Cu_(3)O_(7−δ)(DyBCO) superconductors have been extracted following(i)Ambegaokar‐Baratoff(AB)and(ii)de Gennes(dG)***–voltage(IV)below the critical temperature(T_(c))has been used to extract transport critical current density(J_(c)).The variations of the junction resistances,(RN)with temperature(T)exhibit that below a critical value of the normalised superfluid density(NSD),junctions become very low resistive and exhibit *** of this feature of RN on the energy gaps has also been *** scattering limit is found to be compatible with the maximum of RN(T)as is observed from the corresponding NSD.

关键词： Junction resistance Superfluid density

Characterizing the influence of tide on the physico-chemical parameters and nutrient variability in the coastal surface water of the northern Bay of Bengal during the winter season

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Acta Oceanologica Sinica 2015年第12期34卷 102-111页

作者： sourav das ABHRA Chanda SANDIP Giri ANIRBAN Akhand SUGATA Hazra School of Oceanographic Studies Jadavpur University

The spatial distribution of physico-chemical parameters（sea surface temperature（SST）, p H, sea surface salinity（SSS）, dissolved oxygen（DO） and Secchi depth） along with filterable nutrients（dissolved inorganic nitrate（DIN）,dissolved inorganic phosphate（DIP） and reactive silicate（DSi）） are measured in the winter months of November,December, January and February for four consecutive years from 2009–2010 to 2012–2013 on the shallow continental shelf（〈20 m bathymetry） of the coastal waters（up to 18 km away from shoreline） of the northern Bay of Bengal（n Bo B） during the highest high tide（HHT） and lowest low tide（LLT） hours for the first time. The variability of the coastal biogeochemical environment is assessed during the HHT and LLT hours and for this purpose, seawater samples are collected from seven different locations of a transect in the coastal region. Physicochemical parameters（except SST） show significant difference in magnitude during the HHT and LLT hours respectively. p H, SSS and DO are found to increase in the HHT hours and vice-versa. The data reveal that during the LLT hours, a relative increase of freshwater input in the n Bo B can have elevated the nutrient concentration compared with that observed during the HHT hours. The ratio of nutrient concentration is found to deviate significantly from the Redfield ratio. The abundance of DIP is much higher compared with that of DIN and *** anthropogenic sources of DIP from the upstream flow（especially the domestic effluent of several metropolises） can be mainly attributed behind such an observation. In order to characterize and establish the trend of such variation in such an important bio-climatic region, long-term and systematic ecosystem monitoring in the coastal water of the n Bo B northern Bay of Bengal should be carried out throughout the year.

关键词： physico-chemical parameters nutrient concentration and ratio winter season highest high tide lowest low tide northern Bay of Bengal

Biocompatible silver nanoparticles: An investigation into their protein binding efficacies, anti-bacterial effects and cell cytotoxicity studies

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Journal of Pharmaceutical Analysis 2021年第4期11卷 422-434页

作者： sourav das Leader Langbang Mahabul Haque Vinay Kumar Belwal Kripamoy Aguan Atanu Singha Roy Department of Chemistry National Institute of Technology MeghalayaShillong793003India Department of Biotechnology&Bioinformatics North-Eastern Hill UniversityShillong793022India Department of Bioscience and Bioengineering Indian Institute of Technology GuwahatiAssam781039India

Green synthesis of silver nanoparticles(AgNPs)has garnered tremendous interest as conventional methods include the use and production of toxic chemicals,products,by-products and *** this regard,the synthesis of AgNPs using green tea(GT)extract and two of its components,(-)-epigallocatechin gallate(EGCG)and(+)-catechin(Ct)as capping/stabilizing agents,is *** synthesized AgNPs showed antibacterial activity against the bacterial strains Staphylococcus aureus and Escherichia coli,along with anticancer activity against HeLa *** administering nanoparticles to the body,they come in contact with proteins and results in the formation of a protein corona;hence we studied the interactions of these biocompatible AgNPs with hen egg white lysozyme(HEWL)as a carrier *** quenching mechanism was accountable for the quenching of HEWL fluorescence by the *** binding constant(Kb)was found to be higher for EGCG-AgNPs((2.309±0.018)×104 M-1)than for GT-AgNPs and Ct-AgNPs towards ***-AgNPs increased the polarity near the binding site while Ct-AgNPs caused the opposite effect,but GT-AgNPs had no such observable *** dichroism studies indicated that the AgNPs had no such appreciable impact on the secondary structure of *** key findings of this research included the synthesis of AgNPs using GT extract and its constituent polyphenols,and showed significant antibacterial,anticancer and protein-binding ***-OH groups of the polyphenols drive the in situ capping/stabilization of the AgNPs during synthesis,which might offer new opportunities having implications for nanomedicine and nanodiagnostics.

关键词： Green tea Polyphenols Silver nanoparticles Anti-bacterial Cytotoxicity Hen egg white lysozyme(HEWL)

Tree assemblages and diversity patterns in Tropical Juri Forest,Bangladesh

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Journal of Forestry Research 2015年第1期26卷 159-169页

作者： Swapan Kumar Sarker Muhammad Nur-Un-Nabi Md.Mohasinul Haque Mahmuda Sharmin Sanjay Saha Sonet sourav das Niamjit das Department of Forestry and Environmental Science Shahjalal University of Science & Technology

Juri is a biodiversity-rich primary forest in Bangladesh, which remains ecologically unexplored. We identified tree species and examined the richness, alpha（a）diversity and floristic similarity patterns within the identified communities. Vegetation and environmental data were sampled in 120（0.04 ha） study plots. Tree communities were delimited by two-way indicator species analysis（TWINSPAN）. In total, 78 tree species of 35 families and58 genera were identified. TWINSPAN identified six tree communities： A—Tricalysia singularis; B—Kydia calycina-Castanopsis tribuloides; C—Polyalthia simiarum-Duabanga grandiflora; D—Ficus roxburghii; E—Artocarpus lacucha; F—Artocarpus lacucha. Mean richness, Shannon and Gini-Simpson indices were highest for the Polyalthia simiarum-Duabanga grandiflora community, while Ficus roxburghii showed lowest diversity. Significant differences（p = 0.05） in three diversity indices were recorded between Polyalthia simiarum-Duabanga grandiflora and Ficus roxburghii. Tree compositional similarity was greatest between Kydia calycina-Castanopsis tribuloides and Polyalthia simiarum-Duabanga grandiflora（0.712）.

关键词： Two-way indicator species analysis(TWINSPAN) Richness index Shannon index Gini-Simpson index Tropical forest Conservation

Effect of eccentric and inclined loading on the bearing capacity of strip footing placed on rock mass

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Journal of Mountain Science 2024年第1期21卷 292-312页

作者： Shuvankar das Debarghya CHAKRABORTY Department of Civil Engineering Indian Institute of Technology KharagpurWest Bengal-721302India

This paper deals with the bearing capacity determination of strip footing on a rock mass in hilly area by considering the influence of inclined and eccentric loading. Applying the generalized HoekBrown failure criterion, the failure behavior of the rock mass is modeled with the help of the power cone programming in the lower bound finite element limit analysis framework. Using bearing capacity factor(Ns), the change in bearing capacity of the strip footing due to the occurrence of eccentrically inclined loading is presented. The variations of the magnitude of Ns are obtained by examining the effects of the Hoek-Brown rock mass strength parameters(uniaxial compressive strength(sci), disturbance factor(D), rock parameter(mi), and Geological Strength Index(GSI)) in the presence of different magnitudes of eccentricity(e) and inclination angle(λ) with respect to the vertical plane, and presented as design charts. Both the inclined loading modes, i.e., inclination towards the center of strip footing(+λ) and inclination away from the center of strip footing(-λ), are adopted to perform the investigation. In addition, the correlation between the input parameters and the corresponding output is developed by utilizing the artificial neural network(ANN). Additionally, from sensitivity analysis, it is observed that inclination angle(λ) is the most sensitive parameter. For practicing engineers, the obtained design equation and design charts can be beneficial to understand the bearing capacity variation in the existence of eccentrically inclined loading in mountain areas.

关键词： Eccentric and inclined Power cone programming Rock mass Limit analysis Artificial neural network

Boulder-induced form roughness and skin shear stresses in a gravel-bed stream

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Journal of Mountain Science 2024年第1期21卷 346-360页

作者： das Ratul DATTA Akash Civil Engineering Department National Institute of Technology AgartalaAgartala-799046India

Boulder spacing in mountain rivers and near-wake flow zones within the boulder array is very useful for fish habitat and growth of aquatic *** present study aims to investigate how the boulder array and spacing influence the near-bed flow structures in a gravel-bed *** are staggered over a gravel-bed stream with three different inter-boulder spacing namely(a)large(b)medium and(c)small *** acoustic Doppler velocimeter was used for flow measurements in a rectangular channel and the results were compared with those acquired from numerical *** time-averaged velocity profiles at the near-wake flow zones of boulders experience maximum flow retardation which is an outcome of the boulder-induced form *** ratio of velocity differences associated to form and skin roughness and its positive magnitude reveals the dominance of form roughness closest to the *** roughness computed is 1.75 to 2 times higher than the skin roughness at the near-wake flow *** particular,the collective immobile boulders placed at different inter-boulder spacings developed high and low bed shear stresses closest to the *** low bed shear stresses characterised by a secondary peak developed at the trough location of the boulders is attributed to the skin shear ***,the spatial averaging of time-averaged flow quantities gives additional impetus to present an improved illustration of fluid shear *** formation of form-induced shear stress is estimated to be 17%to 23%of doubleaveraged Reynolds shear stress and partially compensates for the damping of time-averaged Reynolds shear stress in the interfacial *** quadrant analysis of spatial velocity fluctuations depicts that the form-induced shear stresses are dominant in the interfacial sub-layer and have no significance above the gravel-bed surface.

关键词： Array of boulders Near wake flow zones Velocity distributions Skin roughness Form induced shear stresses

A Cocktail of Natural Compounds Holds Promise for New Immunotherapeutic Potential in Head and Neck Cancer

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Chinese Journal of Integrative Medicine 2024年第1期30卷 42-51页

作者： Sunil Kumar Asmita das Department of Biotechnology Delhi Technological UniversityDelhi(110042)India

Objective: To obtain detailed understanding on the gene regulation of natural compounds in altering prognosis of head and neck squamous cell carcinomas(HNSC). Methods: Gene expression data of HNSC samples and peripheral blood mononuclear cells(PBMCs) of HNSC patients were collected from Gene Expression Omnibus(GEO). Differential gene expression analysis of GEO datasets were achieved by the GEO2R tool. Common differentially expressed gerres(DEGs) were screened by comparing DEGs of HNSC with those of PBMCs. The combination was further analyzed for regulating pathways and biological processes that were affected. Results: Totally 110 DEGs were retrieved and identified to be involved in biological processes related to tumor regulation. Then 102 natural compounds were screened for a combination such that the expressions of all 110 commonly DEGs were altered. A combination of salidroside, ginsenoside Rd, oridonin, britanin, and scutellarein was chosen. A multifaceted, multi-dimensional tumor regression was showed by altering autophagy, apoptosis, inhibiting cell proliferation, angiogenesis, metastasis and inflammatory cytokines production. Conclusions: This study has helped develop a unique combination of natural compounds that will markedly reduce the propensity of development of drug resistance in tumors and immune evasion by tumors. The result is crucial to developing a combinatorial natural therapeutic cocktail with accentuated immunotherapeutic potential.

关键词： natural compounds chemopreventive gene expression head and neck cancer immunomodulator salidroside ginsenoside Rd oridonin britanin scutellarein

A machine learning approach for the prediction of pore pressure using well log data of Hikurangi Tuaheni Zone of IODP Expedition 372,New Zealand

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Energy Geoscience

Energy Geoscience 2024年第2期5卷 225-231页

作者： Goutami das Saumen Maiti Machine Learning and Geocomputing Laboratory Department of Applied GeophysicsIIT(ISM)Dhanbad826004JharkhandIndia

Pore pressure(PP)information plays an important role in analysing the geomechanical properties of the reservoir and hydrocarbon field *** prediction is an essential requirement to ensure safe drilling operations and it is a fundamental input for well design,and mud weight estimation for wellbore ***,the pore pressure trend prediction in complex geological provinces is challenging particularly at oceanic slope setting,where sedimentation rate is relatively high and PP can be driven by various complex *** overcome these difficulties,an advanced machine learning(ML)tool is implemented in combination with empirical *** empirical method for PP prediction is comprised of data pre-processing and model establishment ***'s method and Porosity method have been used for PP calculation of the well U1517A located at Tuaheni Landslide Complex of Hikurangi Subduction zone of IODP expedition ***-ray,sonic travel time,bulk density and sonic derived porosity are extracted from well log data for the theoretical framework *** normal compaction trend(NCT)curve analysis is used to check the optimum fitting of the low permeable zone *** statistical analysis is done using the histogram analysis and Pearson correlation coefficient matrix with PP data series to identify potential input combinations for ML-based predictive model *** dataset is prepared and divided into two parts:Training and *** PP data and well log of borehole U1517A is pre-processed to scale in between[-1,+1]to fit into the input range of the non-linear activation/transfer function of the decision tree regression *** Decision Tree Regression(DTR)algorithm is built and compared to the model performance to predict the PP and identify the overpressure zone in Hikurangi Tuaheni Zone of IODP Expedition 372.

关键词： Well log Pore pressure Machine learning(ML) IODP Hikurangi Tuaheni Zone IODP Expedition 372

Krüppel-like factor 2(KLF2),a potential target for neuroregeneration

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Neural Regeneration Research 2024年第11期19卷 2327-2328页

作者： Surajit Hansda Prateeksha Prateeksha Hiranmoy das Department of Pharmaceutical Sciences Jerry H.Hodge School of PharmacyTexas Tech University Health Sciences CenterAmarilloTXUSA

Neurological disorders and injuries lead to the impairment or depletion of neurons in terms of quantity,structure,or function,resulting in the loss of cognitive,emotional,and physical abilities in human ***,in turn,accompanies the shortfall of valuable human resources and economic potential,causing a detriment to *** these challenges,therefore,becomes imperative not only from a humanitarian perspective but also as a means of preserving human capital and bolstering economic prosperity.

关键词： companies injuries potential

Ultrasound Needle Guidance System for Precision Vaccinations and Drug Deliver

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Circuits and Systems 2021年第1期12卷 1-12页

作者： Semih Aslan Mahbubur Rahman sourav das Bonnie Schnitta Ingram School Engineering Texas State University San Marcos TX USA SoundSense LLC Wainscott NY USA

Image-guided needles are currently used for drug delivery in bodies, but the additional time associated with aligning and maintaining the needle’s position results in increased patient discomfort or risk of invasion of the human body. In this paper, a needle guidance system using piezoelectric materials is designed and analyzed for precise drug delivery without damaging parts of the body and improving processing time. A piezoelectric generates an ultrasound wave that can propagate through different mediums, and a second piezoelectric crystal can receive that energy and convert it into voltage. A 1D real-time image represents the changes of the voltage induced in the double piezoelectric crystal. Extensive data analysis and visualization are done using different obstacles and location of the needle verified for other mediums. The presence of obstacles in between those crystals can be identified in the real-time grayscale image. The needle can reach its destination using this image information as directional guidance. This guided drug delivery improves patient recovery time and eliminates extra injuries that can be caused due to wrong needle injections, such as lumbar puncture-related nerve damage.

关键词： Ultrasonic Needle Guidance System eSNR Image Processing Piezo