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Hydro-chemical study of the evolution of interstellar pre-biotic molecules during the collapse of molecular clouds

Research in Astronomy and Astrophysics 2012年第12期12卷 1613-1624页

作者： Liton Majumdar ankan das Sandip K. Chakrabarti Sonali Chakrabarti Indian Centre for Space Physics Chalantika 43Garia Station RoadKolkata-700084India S.N.Bose National Centre for Basic Sciences Salt LakeKolkata-700098India Maharaja Manindra Chandra College 20 Ramakanto Bose StreetKolkata-700003India

One of the stumbling blocks for studying the evolution of interstellar molecules is the lack of adequate knowledge about the rate coefficients of various reactions which take place in the interstellar medium and molecular *** theoretical models of rate coefficients do exist in the literature for computing abundances of complex pre-biotic *** far these have been used to study the abundances of these molecules in ***,in order to obtain more accurate final compositions in these media,we have calculated the rate coefficients for the formation of some of the most important interstellar pre-biotic molecules by using quantum chemical *** use these rates inside our hydro-chemical model to examine the chemical evolution and final abundances of pre-biotic species during the collapsing phase of a *** find that a significant amount of various pre-biotic molecules could be produced during the collapse phase of a *** thoroughly study the formation of these molecules via successive neutral-neutral and radical-radical/radicalmolecular *** present the time evolution of the chemical species with an emphasis on how the production of these molecules varies with the depth of a cloud. We compare the formation of adenine in interstellar space using our rate-coefficients and using those obtained from existing theoretical *** routes of the pre-biotic molecules are found to be highly dependent on the abundances of the reactive species and the rate coefficients involved in the *** presence of grains strongly affects the abundances of the gas phase *** also carry out a comparative study between different pathways available for the synthesis of adenine,alanine, glycine and other molecules considered in our *** the huge abundances of the neutral reactive species,production of adenine is found to be strongly dominated by the radical-radical/radical-molecular reaction *** all the reactio

关键词： ISM clouds-astrochemistry-stars formation

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Phenol in High-mass Star-forming Regions

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Research in Astronomy and Astrophysics 2022年第6期22卷 256-268页

作者： Rana Ghosh Milan Sil Suman Kumar Mondal Prasanta Gorai Dipen Sahu Rahul Kumar Kushwaha Bhalamurugan Sivaraman ankan das Indian Centre for Space Physics 43 ChalantikaGaria Station RoadKolkata 700084India S.N.Bose National Centre for Basic Sciences Salt LakeKolkata 700106India Department of Space Earth&EnvironmentChalmers University of TechnologySE-41296 GothenburgSweden Institute of Astronomy and Astrophysics Academia Sinica Taipei Taipei 10617China Atomic and Molecular Physics Laboratory Institute for Nuclear Research(Atomki)Debrecen H-4026Hungary Physical Research Laboratory NavrangpuraAhmedabad 380009India

Phenol,which belongs to the C_(6)H_(6)O isomeric group,is the simplest molecule in the family of alcohol of the aromatic *** phenol has yet to be detected in the interstellar medium,a tentative identification was reported toward the Orion KL hot core using the IRAM-30 m line *** explore some more species of this isomeric group,we consider ten species to study the fate of their astronomical *** is noticed that phenol is the most energetically favorable isomer of this *** contrast,propargyl ether is the least favorable(having relative energy~103kcal mol^(-1)compared to phenol)species of this *** far,the studies associated with the formation of phenol are heavily concentrated on combustion ***,we suggest a few key reactions(C_(6)H_(6)+OH→C_(6)H_(5)+H_(2)O,C_(6)H_(6)+O→C_(6)H_(5)OH,C_(6)H_(6)+H→C_(6)H_(5)+H_(2),and C_(6)H_(5)+OH→C_(6)H_(5)OH+hν)for the formation of *** these pathways are included in a large gas-grain chemical network to study its formation in high mass star-forming regions and dark cloud *** is noticed that the phenyl(-C_(6)H_(5))formation by the ice-phase hydrogen abstraction reaction of benzene(i.e.,C_(6)H_(6)+OH→C_(6)H_(5)+H_(2)O if allowed at~10 K)could serve as the starting point for the formation of phenol in the gas phase by radiative association reaction C_(6)H_(5)+OH→C_(6)H_(5)OH+hν.The gasphase reaction C_(6)H_(6)+O→C_(6)H_(5)OH significantly contributes to the formation of phenol,when the ice-phase reaction C_(6)H_(6)+OH→C_(6)H_(5)+H_(2)O is not considered at low *** 4 ALMA archival data of a hot molecular core,G10.47+0.03,are *** yields an upper limit on phenol abundance of 5.19×10^(-9).Our astrochemical model delivers an upper limit on phenol abundance of~2.20×10^(-9)in the hot molecular core,whereas its production in the dark cloud is not satisfactory.

关键词： astrochemistry-ISM abundances-ISM molecules-(ISM:)evolution

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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

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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

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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

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High performance in Zintl thermoelectrics via reduction in crystal field splitting energy

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Science China Materials 2024年第10期67卷 3424-3425页

作者： Anustoop das Kanishka Biswas New Chemistry Unit School of Advanced Materials and International Centre for Materials ScienceJawaharlal Nehru Centre for Advanced Scientific Research(JNCASR)Jakkur P.O.Bangalore 560064India

Sustainable thermoelectric materials open an avenue of emission-free as well as fast-responding recycling of energy in terms of heat to *** efficiency(η)of such conversion is primarily guided by the dimensionless the... 详细信息

关键词： splitting energy crystal

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Multifunctional applications of gadolinium-doped cerium oxide(Ce1-xGdxO2-?) ceramics:A review

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Journal of Rare Earths 2024年第10期42卷 1817-1834页

作者： Subhadip das Rakesh Bhaskar Kannan Badri Narayanan Department of Ceramic Engineering National Institute of Technology Rourkela School of Chemical Engineering Yeungnam University

Cerium oxide（CeO2）,or ceria,and its doped derivatives have been extensively studied for several decades and are well-known oxides valued for their unique structural properties and wide range of *** materials play a crucial role in sustainable development within *** modification through de fect e ngineering of the highly stable cubic fluorite phase enhances the versatility of this doped ceria to a new *** the numerous dopants of the CeO2matrix,ceria doped with gadolinium（Gd）,known as Ce1-xGdxO2-?（CGO）,is gaining popularity due to its *** introduction of defect-induced vacancies in the oxygen sublattice（V_o） and a change in the average valence of cerium(Ce3+/Ce4+) are primarily responsible for the improved performance compared to pristine *** materials are currently undergoing intensive research for potential use as electrolytes in intermediate-temperature solid oxide fuel cells（IT-SOFCs） and dense oxygen-permeable membranes（OPMs）.Additionally,they are being commercially utilized for power generation and oxygen *** materials are also attracting significant attention in various fields such as optics,photocatalysis,electrostriction,spintronics,gas sensing,electrocatalysis,and biomedical *** review paper aims to compile the latest contributions to CGO materials and comprehensively cover their various application *** crystal structure,defect equilibrium in Gd3+-doped CeO2,the origin of multifunctionality,and the prospects of these materials are also exclusively discussed.

关键词： Biomedicine Gadolinium-doped CeO2 Gas sensors Photo/electrocatalysts Rare earths Spintronics

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An advantageous charging/discharging scheduling of electric vehicles in a PV energy enhanced power distribution grid

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Green Energy and Intelligent Transportation 2024年第2期3卷 60-78页

作者： Pritam das Partha Kayal Department of Electrical Engineering National Institute of Technology SilcharAssam788010India

Electric vehicles(EVs)are going to overrule the transportation sector due to their pollution-free technology and low running ***,charging the EVs causes significant power demand and stress on the power delivery *** challenge can be tackled well when charging and discharging scheduling are coordinated with intelligent EV *** this work,two-stage charging and discharging scheduling are *** the first stage,a time scheduling algorithm is structured to identify EV charging/discharging slots at different hours,and at a later stage,the slots are optimally distributed among different charging *** of the EVs towards the EVCSs has been designed to enhance the useful participation of the EVs in the charging and discharging *** this regard,a possible number of EVs in the test region has been forecasted with a regression *** adequacy of the combined charging-discharging and location scheduling model is tested on a typical PV-enhanced 28-bus Indian distribution *** case studies containing three sub-cases in each have been performed incorporating the choice of the EV owners towards charging and discharging in different time slots in a *** case studies have resulted in a peak-to-average ratio(PAR)of 1.151,0,1.165,0,1.196,8,1.165,0,1.180,9,1.196,8,1.196,8,1.196,8 and 1.196,8 for the 24-h demand pattern in Case-1a,Case-1b,Case-1c,Case-2a,Case-2b,Case-2c,Case-3a,Case-3b and Case-1c respectively in comparison to a PAR of 1.2 for the 24-h demand in base case.

关键词： Charging-discharging scheduling Electric vehicles Solar irradiance forecasting Optimization Distribution network

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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 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

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Rice breeding for low methane and high yields

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Plant Communications 2024年第5期5卷 94-96页

作者： Suvendu das Pil Joo Kim Institute of Agriculture and Life Sciences Gyeongsang National UniversityJinju 660-701South Korea Division of Applied Life Science Gyeongsang National UniversityJinju 660-701South Korea

Rice is the staple food for more than half of the world’s population,and the demand for rice is expected to increase by 28%by 2050(Jiang et al.,2017).However,rice production is one of the largest anthropogenic sources of the potent greenhouse gas methane(CH4),accounting for 22%of total agricultural CH4 emissions(Qian et al.,2023).Therefore,to achieve sustainable intensification of rice cultivation,it is necessary to increase yields while reducing CH4 *** management techniques to reduce CH4 emissions while maintaining high yields have been studied extensively over the past few decades,but crop breeding to reduce CH4 emissions without compromising yields has received less attention(Kwon et al.,2023).

关键词： breeding methane yields

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