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Binding interaction of phosphorus heterocycles with bovine serum albumin:A biochemical study

Journal of Pharmaceutical Analysis 2017年第1期7卷 19-26页

作者： Swarup Roy Raj kumar Nandi Sintu Ganai k.c. majumdar Tapan k. Das Department of Biochemistry and Biophysics University of Kalyani Kalyani 741235 West Bengal India Department of chemistry University of Kalyani Kalyani 741235 West Bengal India

Interaction between bovine serum albumin(BSA) and phosphorus heterocycles(PHs) was studied using multispectroscopic techniques. The results indicated the high binding affinity of PHs to BSA as it quenches the intrinsic fluorescence of BSA. The experimental data suggested the fluorescence quenching mechanism between PHs and BSA as a dynamic quenching. From the UV–vis studies, the apparent association constant(k_(app)) was found to be 9.25×10~2, 1.27×10~4and 9.01×10~2L/mol for the interaction of BSA with PH-1, PH-2 and PH-3,respectively. According to the F?rster's non-radiation energy transfer(FRET) theory, the binding distances between BSA and PHs were calculated. The binding distances(r) of PH-1, PH-2 and PH-3 were found to be2.86, 3.03, and 5.12 nm, respectively, indicating energy transfer occurs between BSA and PHs. The binding constants of the PHs obtained from the fluorescence quenching data were found to be decreased with increase of temperature. The negative values of the thermodynamic parameters ΔH, ΔS and ΔG at different temperatures revealed that the binding process is spontaneous; hydrogen bonds and van der Waals interaction were the main force to stabilize the complex. The microenvironment of the protein-binding site was studied by synchronous fluorescence and circular dichroism(cD) techniques and data indicated that the conformation of BSA changed in the presence of PHs. Finally, we studied the BSA-PHs docking using Auto Dock and results suggest that PHs is located in the cleft between the domains of BSA.

关键词： BSA Spectroscopy Phosphorus heterocycles BSA-PHs docking

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Dynamics of self-hybridized exciton–polaritons in 2D halide perovskites

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Light(Science & Applications) 2024年第1期13卷 13-22页

作者： Surendra B.Anantharaman Jason Lynch christopher E.Stevens christopher Munley chentao Li Jin Hou Hao Zhang Andrew Torma Thomas Darlington Francis coen kevin Li Arka majumdar PJames Schuck Aditya Mohite Hayk Harutyunyan Joshua R.Hendrickson Deep Jariwala Department of Electrical and Systems Engineering University of PennsylvaniaPhiladelphiaPA19104USA kBR Inc. BeavercreekOH45431USA Air Force Research Laboratory Sensors DirectorateWright-Patterson Air Force BaseOH45433USA Department of Physics University of WashingtonSeattleWA98195USA Department of Physics Emory UniversityAtlantaGA30322USA Department of chemical and Biomolecular Engineering Rice UniversityHoustonTX77005USA Department of Materials Science and Nanoengineering Rice UniversityHoustonTX77005USA Applied Physics Program Smalley‐Curl InstituteRice UniversityHoustonTX77005USA Department of Mechanical Engineering Columbia UniversityNew YorkNY10027USA Department of Electrical and computer Engineering University of WashingtonSeattleWA98195USA

Excitons,bound electron–hole pairs,in two-dimensional hybrid organic inorganic perovskites(2D HOIPs)are capable of forming hybrid light-matter states known as exciton-polaritons(E–Ps)when the excitonic medium is confined in an optical cavity.In the case of 2D HOIPs,they can self-hybridize into E–Ps at specific thicknesses of the HOIP crystals that form a resonant optical cavity with the excitons.However,the fundamental properties of these self-hybridized E–Ps in 2D HOIPs,including their role in ultrafast energy and/or charge transfer at interfaces,remain unclear.Here,we demonstrate that>0.5µm thick 2D HOIP crystals on Au substrates are capable of supporting multiple-orders of self-hybridized E–P modes.These E–Ps have high Q factors(>100)and modulate the optical dispersion for the crystal to enhance sub-gap absorption and emission.Through varying excitation energy and ultrafast measurements,we also confirm energy transfer from higher energy E–Ps to lower energy E–Ps.Finally,we also demonstrate that E–Ps are capable of charge transport and transfer at interfaces.Our findings provide new insights into charge and energy transfer in E–Ps opening new opportunities towards their manipulation for polaritonic devices.

关键词： charge polar excitation

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calculation of Available Transfer capability Using Hybrid chaotic Selfish Herd Optimizer and 24 Hours RES-thermal Scheduling

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chinese Journal of Electrical Engineering 2023年第4期9卷 54-72页

作者： kingsuk majumdar Provas kumar Roy Subrata Banerjee Department of Electrical Engineering Dr.B C Roy Engineering CollegeDurgapur 713206India Department of Electrical Engineering Kalyani Government Engineering CollegeKalyani 741235India Department of Electrical Engineering NIT DurgapurDurgapur 713209India

As fossil fuel stocks are being depleted,alternative sources of energy must be explored.consequently,traditional thermal power plants must coexist with renewable resources,such as wind,solar,and hydro units,and all-day planning and operation techniques are necessary to safeguard nature while meeting the current demand.The fundamental components of contemporary power systems are the simultaneous decrease in generation costs and increase in the available transfer capacity(ATc)of current systems.Thermal units are linked to sources of renewable energy such as hydro,wind,and solar power,and are set up to run for 24 h.By contrast,new research reports that various chaotic maps are merged with various existing optimization methodologies to obtain better results than those without the inclusion of chaos.chaos seems to increase the performance and convergence properties of existing optimization approaches.In this study,selfish animal tendencies,mathematically represented as selfish herd optimizers,were hybridized with chaotic phenomena and used to improve ATc and/or reduce generation costs,creating a multi-objective optimization problem.To evaluate the performance of the proposed hybridized optimization technique,an optimal power flow-based ATc was enforced under various hydro-thermal-solar-wind conditions,that is,the renewable energy source-thermal scheduling concept,on IEEE 9-bus,IEEE 39-bus,and Indian Northern Region Power Grid 246-bus test systems.The findings show that the proposed technique outperforms existing well-established optimization strategies.

关键词： Available transfer capability(ATc) biogeography-based optimization(BBO) chaotic map chaotic selfish herd optimizer(cSHO) grey wolf optimizer(GWO) optimum power flow(OPF) power generation cost(PGc) renewable energy sources(RES) selfish herd optimizer(SHO)

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Fast extended depth of focus meta-optics for varifocal functionality

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Photonics Research 2022年第3期10卷 828-833页

作者： James E.M.Whitehead Alan Zhan Shane colburn Luocheng Huang Arka majumdar Department of Electrical and computer Engineering University of WashingtonSeattleWashingtonD.C.98195USA Tunoptix SeattleWashingtonD.C.98195USA Department of Physics University of WashingtonSeattleWashingtonD.C.98195USA

Extended depth of focus(EDOF)optics can enable lower complexity optical imaging systems when compared to active focusing solutions.With existing EDOF optics,however,it is difficult to achieve high resolution and high collection efficiency simultaneously.The subwavelength spacing of scatterers in a meta-optic enables the engineering of very steep phase gradients;thus,meta-optics can achieve both a large physical aperture and a high numerical aperture.Here,we demonstrate a fast(f/1.75)EDOF meta-optic operating at visible wavelengths,with an aperture of 2 mm and focal range from 3.5 mm to 14.5 mm(286 diopters to 69 diopters),which is a 250×elongation of the depth of focus relative to a standard lens.Depth-independent performance is shown by imaging at a range of finite conjugates,with a minimum spatial resolution of∼9.84μm(50.8 cycles/mm).We also demonstrate operation of a directly integrated EDOF meta-optic camera module to evaluate imaging at multiple object distances,a functionality which would otherwise require a varifocal lens.

关键词： optics enable otherwise

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Soldiers' load carriage performance in high mountains: a physiological study

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Military Medical Research 2017年第3期4卷 132-140页

作者： Tirthankar chatterjee Debojyoti Bhattacharyya Anilendu Pramanik Madhusudan Pal Deepti majumdar Dhurjati majumdar Defence Institute of Physiology and Allied Sciences Defence Research & Development Organisation Ministry of DefenceGovernment of India Retired from-Institute of Nuclear Medicine and Allied Sciences Defence Research and Development Organization Ministry of DefenceGovernment of India

Background: The present study was designed to evaluate load carriage performance at extremely high altitudes with different loads and walking speeds in terms of physiological evaluation. The degree of maximum oxygen consumption changes at high altitudes was also examined.Methods: Twelve Indian Army soldiers were acclimatized at altitudes of 3,505 m and 4,300 m. They walked for 10 minutes on a motorized treadmill at 2.5km/h and 3.5km/h speeds during carrying no loads and three magnitudes of load(10.7kg, 21.4kg, 30kg) at both altitudes. Physiological parameters such as oxygen consumption, energy expenditure, heart rate, and ventilation were recorded for each breath using a gas analyzer. The rating of perceived exertion was also noted after each load carriage session. Maximal oxygen consumption(VO2max) was measured at sea level and the two high altitudes, and respective relative workloads(% of VO2max) were calculated from oxygen consumption. Repeated measure ANOVA was applied to reveal the significant effects of the independent variables.Results: The participants had significant reductions in VO2 max with rising altitude. Marked increases in almost all physiological parameters were observed with increasing load, altitude, and speed. The soldiers expressed heavy perceived exertion levels with higher loads at 3.5km/h at the two high altitudes.conclusions: considering the physiological responses, expressions of perceived exertion and changes in relative work load at both of the high altitudes. Indian soldiers are advised to walk slowly with adequate rest in between their schedules and to carry not more than 32% of their body weight.

关键词： Load carriage High altitude Walking speed Physiological responses

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Antimicrobial activity of cannabis sativa,Thuja orientalis and Psidium guajava leaf extracts against methicillin-resistant Staphylococcus aureus

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Journal of Integrative Medicine 2018年第5期16卷 350-357页

作者： Shohini chakraborty Nashra Afaq Neelam Singh Sukanta majumdar Department of Microbiology Saaii College of Medical Science and Technology Microbiology and Microbial Biotechnology Laboratory Department of BotanyUniversity of Gour Banga

Objective： This study examined the antimicrobial activity of cannabis sativa, Thuja orientalis and Psidium guajava against methicillin-resistant Staphylococcus aureus （MRSA） and used a standardized purification protocol to determine the presence and abundance of bioactive compounds in the leaf extracts. Methods： In vitro antimicrobial activities of the ethanolic extracts of c sativa, T. orientalis and P. guajava were tested against MRSA. The presence of bioactive molecules in these three leaves was evaluated using biochemical assays and high-performance thin-layer chromatography （HPTLc）. Results： Resistance to methicillin, penicillin, oxacillin and cefoxitin was observed in each of the clinical and nonclinical MRSA isolates. However, they were still vulnerable to vancomydn. Used individually, the 50% extract of each plant leaf inhibited MRSA growth. A profound synergism was observed when c sativa was used in combination with T. orientalis （1：1 ） and when P. guajava was used in combination with T. orientalis （1：1 ）. This was shown by larger zones of inhibition. This synergism was probably due to the combined inhibitory effect of phenolics present in the leaf extracts （i.e., quercetin and gallic acid） and catechin, as detected by HPTLc. conclusion： The leaf extracts of c sativa, T. orientalis and P. guajava had potential for the control of both hospital- and community-acquired MRSA. Moreover, the inhibitory effect was enhanced when extracts were used in combination.

关键词： Methicillin-resistant Staphy lococcus aureus Antimicrobial activity Plant extracts Synergistic effect High-performance thin-layer chromatography

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Oilfield geothermal resources of the Upper Assam Petroliferous Basin,NE India

Energy Geoscience

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Energy Geoscience 2021年第4期2卷 246-253页

作者： Dilip majumdar Abhilekha Devi Department of Applied Geology Dibrugarh UniversityAssam786004India

Extracting geothermal energy from the oil-producing fields is an experimental venture globally.The exploitation and utilization of geothermal energy can partly reduce the larger dependence on conventional non-renewable energy sources like oil,gas,coal,and other fossil fuels,and has a bright prospect.The Upper Assam Basin is a mature petroliferous basin of NE India,where there are several hundred low production,high water cut,or abandoned oil and gas wells that can be retrofitted as geothermal wells instead of drilling new ones.This will help bridge the gap of growing energy demand and limited supply in energy-deficient state like Assam.Situated away from the active plate boundaries and in lack of active volcanism,the Upper Assam Basin remains a low-to-medium enthalpy geothermal fluid regime.The deeper reservoir in this regard can,therefore,be the best candidate for the introspection of the potential geothermal energy reservoir reconnaissance.The selection of a deeper horizon considered in the present case has been the stratified reservoirs of the Lakadong-Therria(Lk-Th)Formation,Sylhet Group of the Lower Eocene age occurring at a variable depth of 3400 me 4600 m.The Lk-Th Formation possesses a fair-quality reservoir with lateral continuity and favourable petrophysical properties.In this study,representative gamma-ray(GR)and resistivity(R)logs were examined to work out lithology,and bed boundary demarcation,etc.The total Formation thickness varies from 97 to 157 m;the individual sand body thickness is up to 6 m.Other reservoir parameters,e.g.,porosity(φ=8-33%),water saturation(S_(w)=4.57-95.15%),geothermal gradient(2.71℃/100m to 3.92 c/100 m at 4300 m and 3608 m)respectively,and theoretical estimate of high heat flux in the range 70e100 mW/m^(2)/s,are the necessary yard-stick to measure the subsurface geothermal reserves.Efficient energy extraction will have the potential in facilitating energy utilization for industrial purposes,especially in tea processing units present nearby oilfields and also for power genera

关键词： Upper Assam Petroliferous Basin Geothermal energy Water cut Abandoned oil/gas well Geothermal gradient

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Observation of~100%valley-coherent excitons in monolayer MoS_(2) through giant enhancement of valley coherence time

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光:科学与应用(英文版) 2023年第8期12卷 1644-1650页

作者： Garima Gupta kenji Watanabe Takashi Taniguchi kausik majumdar Department of Electrical communication Engineering Indian Institute of ScienceBangaloreIndia Research center for Functional Materials National Institute for Materials ScienceTsukubaJapan international center for Materials Nanoarchitectonics National Institute for Materials ScienceTsukubaJapan

In monolayer transition metal dichalcogenide semiconductors,valley coherence degrades rapidly due to a combination of fast scattering and inter-valley exchange interaction.This leads to a sub-picosecond valley coherence time,making coherent manipulation of exciton a highly challenging task Using monolayer MoS_(2) sandwiched between top and bottom graphene,here we demonstrate fully valley-coherent excitons by observing~100%degree of linear polarization in steady state photoluminescence.This is achieved in this unique design through a combined effect of(a)suppression in exchange interaction due to enhanced dielectric screening,(b)reduction in exciton lifetime due to a fast inter-layer transfer to graphene,and(c)operating in the motional narrowing regime.We disentangle the role of the key parameters affecting valley coherence by using a combination of calculation(solutions of Bethe-Salpeter and Maiallle-Silva-Sham equations)and a careful choice of design of experiments using four different stacks with systematic variation of screening and exciton lifetime.To the best of our knowledge,this is the first report in which the excitons are found to be valley coherent in the entire lifetime in monolayer semiconductors,allowing optical readout of valley coherence possible.

关键词： coherent monolayer lifetime

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L-Plastin deficiency produces increased trabecular bone due to attenuation of sealing ring formation and osteoclast dysfunction

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Bone Research 2020年第1期8卷 53-62页

作者： Meenakshi Achellaiah Megan cMoorer Sunipa majumdar Hanan Aljohani Sharon cMorley Vanessa Yingling Joseph PStains Department of Oncology and Diagnostic Sciences School of DentistryUniversity of MarylandBaltimoreMDUSA Department of Orthopedics University of Maryland School of MedicineBaltimoreMDUSA Department of Pediatrics Division of Infectious Diseasesand Department of Pathology and ImmunologyWashington University School of MedicineSt.LouisMOUSA Department of kinesiology California State UniversityEast BayHaywardCAUSA

Bone resorption requires the formation of complex, actin-rich cytoskeletal structures. During the early phase of sealing ring formation by osteoclasts, L-plastin regulates actin-bundling to form the nascent sealing zones(NSZ). Here, we show that L-plastin knockout mice produce osteoclasts that are deficient in the formation of NSZs, are hyporesorptive, and make superficial resorption pits in vitro. Transduction of TAT-fused full-length L-plastin peptide into osteoclasts from L-plastin knockout mice rescued the formation of nascent sealing zones and sealing rings in a time-dependent manner. This response was not observed with mutated full-length L-plastin(Ser-5 and-7 to Ala-5 and-7) peptide. In contrast to the observed defect in the NSZ, L-plastin deficiency did not affect podosome formation or adhesion of osteoclasts in vitro or in vivo. Histomorphometry analyses in 8-and 12-week-old female L-plastin knockout mice demonstrated a decrease in eroded perimeters and an increase in trabecular bone density, without a change in bone formation by osteoblasts. This decrease in eroded perimeters supports that osteoclast function is attenuated in L-plastin knockouts. Micro-cT analyses confirmed a marked increase in trabecular bone mass. In conclusion, female L-plastin knockout mice had increased trabecular bone density due to impaired bone resorption by osteoclasts. L-plastin could be a potential target for therapeutic interventions to treat trabecular bone loss.

关键词： sealing impaired fused

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changes of woody species diversity, horizontal and vertical distribution of stems across interior to outside within a primate rich habitat of Northeast India

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Journal of Forestry Research 2016年第4期27卷 787-798页

作者： koushik majumdar Bal krishan choudhary Badal kumar Datta Plant Taxonomy and Biodiversity Lab. Department of Botany Tripura University

The interior forest of protected area（PA）recover quickly in terms of greater diversity and structural complexity than peripheral and outsides, which may be due to high plant-frugivore interactions in the interior forest than the disturbed outsides. To describe the structural and functional differences in tree communities from interior to outside forests with in small PA, we quantitatively analyzed the vegetation of Trishna Wildlife Sanctuary, a rich primate habitat of Northeast India. Vegetation was sampled at c10 cm girth at breast height by 10 m 9 500 m sized20 line transects（10 ha） laid in the interior（N = 7）,peripheral（N = 7） and outside（N = 6） zones of this sanctuary. All transects were ordinated by Principal component Analysis based on correlation between diversity and existing disturbance indices. We found significant differences（P ／ 0.05） in taxonomic richness and diversity indices between the habitat. Van diagram confirmed greater unique species richness in the interior zone（64） than peripheral（28） and outside（6） zones. Overall density（ha-1） did not differed across the zones, but basal area（m2ha-1） was significantly（P ／ 0.01） high in peripheral zone. Vertical distribution of stem density was linearly declined across zones（r2adj[ 0.70; P ／ 0.01） with increase in the canopy height. Horizontal distribution of adult stems showed significant inverse quadratic relationship（r2adj[ 0.80; P ／ 0.001）, which suggests very low density of canopy forming voluminous trees in the interior zone.Immediate protection, restoration and management of interior regions are required to preserve local plant genetic diversity and also to maintain suitable habitat for threatened wildlife.

关键词： interior outside habitat restoration Northeast disturbance quickly inverse preserve quadratic

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