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Modulations in seed micromorphology reveal signature of adaptive species-diversification in <i>Dendrobium</i>(Orchidaceae)

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Open Journal of Ecology 2014年第2期4卷 33-42页

作者： Bhupendra Chaudhary pritam chattopadhyay Nirmalya Banerjee Department of Botany Visva-Bharati University Santiniketan India School of Biotechnology Gautam Buddha University Greater Noida India

During speciation in flowering plants, many morphological characters were evolved in response to continuous selection pressure. Such characters are largely governed by genetic changes or get modulated according to ecological adaptations. To explore the potential of latter, a novel comparative analysis of seed micromorphology and ultrastructure was performed in twenty species in the genus Dendrobium (Orchidaceae) from well-defined altitude based phytogeographical realms i.e. temperate, subtropical and tropical regions. Seed morphological characteristics from all collected species were examined using 13 quantitative traits descriptors. Comparative seed morphology revealed that the species from temperate region have larger seed volumes and seed volume/embryo volume ratio than species from subtropical or tropical regions irrespective of their phylogenetic association. Hence, phylogenetically related species emphasized their preference for a climatic region as their prime habitat. Similar trends towards gradual increase of percentage free air space were observed in the species of tropical to subtropical and subtropical to temperate regions. The higher percentage of free air space may have an advantage for the species from temperate region with relatively low atmospheric pressure that had greater buoyancy for optimal seed dispersal. Also, phylogenetically distant species from a particular climatic region, showed characteristic features of the testa cell walls sculptured with bead-like orna-mentations or covered with cottony white substances. Based on these observations, it may be concluded that seed volume, % free air space and seed coat ornamentation in Dendrobium species are signatures of adaptation according to climatic preferences rather than their selection during speciation.

关键词： Dendrobium Seed Micromorphology Phytogeography Tropical Subtropical Temperate Phylogeny

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Understanding the Phylomorphological Implications of Pollinia from <i>Dendrobium</i>(Orchidaceae)

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American Journal of Plant Sciences 2012年第6期3卷 816-828页

作者： Bhupendra Chaudhary pritam chattopadhyay Neetu Verma Nirmalya Banerjee 1School of Biotechnology Gautam Buddha University Greater Noida India Department of Botany Visva-Bharati University San-tiniketan India.

We aim to evaluate the evolutionary trends of pollen ultra-structures and microstructures in the light of molecular phylogeny, and to test whether pollen micromorphology is a predictor of interspecific phylogenetic relationship or a consequence of ecological influences. Using scanning electron microscopy pollinia micromorphologies of 18 species of the genus Dendrobium were comprehensively examined. A phylogenetic tree from ribosomal-ITS2 sequences was constructed reflecting molecular phylogeny. In result, two major clusters were identified representing the sections Aporum, Formoase Dendrobium and Holochrysa. The section Dendrobium could be further classified, for the first time, into two clades sharing the same root of origin. Variations in the shape of pollinia were distinct and consistent constituting six novel groups. Other qualitative/quantitative keys to pollinia showed congruence with molecular phylogeny and supported the correlated evolution of these traits. Concurrently pollen sculpturing also showed large variation in exine morphology (rugular/psilate to psilate-scabrate/rugulate-scabrate) providing explicit clues for phylogenetic trend of exine evolution. For the characteristic sculpturing on the pollinia surface, a simple version of pre-pattern model is also hypothesized for deeper insight into pattern formation in other biological systems. Results indicated that distinct groups of Dendrobium species have parallel and independent evolution accompanied with genetic changes occurred during species diversification. Thus pollen micromorphology is a good candidate for inferring the genetic relationship at inter-specific level having phylogenetic implications even using abundant palynological records.

关键词： Pollinia Orchids ITS2 Exine Morphology Phylogeny

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Impact of density of coating agent on antibacterial activity of silver nanoparticle impregnated plasma treated activated carbon

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Journal of Environmental Sciences 2018年第5期30卷 136-144页

作者： pritam Biswas Rajdip BANDyopadhyaya Department of Chemical Engineering Indian Institute of Technology Bombay

To use stabilized nanoparticles（NPs） in water as disinfectants over a very long period, the amount of coating agent（for NP stabilization） needs to be optimized. To this end, silver nanoparticles（Ag-NPs） with two different coating densities of tri-sodium citrate（12.05 and46.17 molecules/nm2, respectively）, yet of very similar particle size（29 and 27 nm, respectively）were synthesized. Both sets of citrate capped NPs were then separately impregnated on plasma treated activated carbon（AC）, with similar Ag loading of 0.8 and 0.82 wt.%, respectively. On passing contaminated water（containing 10~4 CFU Escherichia coli/m L of water） through a continuous flow-column packed with Ag/AC, zero cell concentration was achieved in 22 and 39 min, with Ag-NPs（impregnated on AC, named as Ag/AC） having lower and higher coating density, respectively. Therefore, even on ensuring similar Ag-NP size and loading, there is a significant difference in antibacterial performance based on citrate coating density in Ag/*** is observed in lower coating density case, due to both：（i） higher Ag~＋ ion release from Ag-NP and（ii） stronger binding of individual Ag-NPs on AC. The latter ensures that, Ag-NP does not detach from the AC surface for a long duration. TGA-DSC shows that Ag-NPs with a low coating density bind to AC with 4.55 times higher adsorption energy, compared to Ag/AC with a high coating density, implying stronger binding. Therefore, coating density is an important parameter for achieving higher antibacterial efficacy, translating into a faster decontamination rate in experiments, over a long period of flow-column operation.

关键词： Silver nanoparticles Activated carbon Escherichia coliCitrate coating Coating density Water disinfection

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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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Remediation of Fly Ash Dumpsites Through Bioenergy Crop Plantation and Generation: A Review

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Pedosphere 2018年第4期28卷 561-580页

作者： Madhumita ROY Roopali ROYCHOWDHURY pritam MUKHERJEE Department of Biotechnology Techno India University

Utilization of fly ash, a byproduct of coal combustion in thermal power plants, is a sustainable use of waste for power *** fly ash as waste in landfills/ash ponds may not only be regarded as a loss of valuable land and essential nutrients, but also pose a significant health hazard due to fine air-borne particles and leaching of heavy metals. The presence of essential macro-and micronutrients and its porosity make fly ash an excellent soil amendment for plant growth as an organic nitrogen(N) and carbon(C)supplementation. As harmful heavy metals make fly ash unsafe for agronomy, bioenergy crop plantation and energy generation from different thermochemical conversions of the biomass would be an ideal method for coal fly ash utilization through which carbon-neutral fuel can be generated from fossil fuel, thus reducing climate change impact. This review summarizes the development of bioenergy plantation and silviculture at fly ash dumpsites with an integrated phyto-bio-rhizo-mycoremediation approach and assesses utilization of the valuable biomass for thermal energy, electricity, and biofuel generation with inclusion of a SWOT analysis(a strategic technique typically used to help identify the strength, weakness, opportunities, and threat). Bioenergy crop production through integrated phytomanagement can generate billions of dollars of wealth from waste and provides a sustainable solution for fly ash management,with environmental, economic, and social benefits.

关键词： biofuel production biomass-generating crops carbon-neutral fuel health risk heavy metal land use phytoremediation soil amendment

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Load shedding strategy coordinated with storage device and D-STATCOM to enhance the microgrid stability

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Protection and Control of Modern Power Systems 2019年第1期4卷 262-280页

作者： Sheetal Chandak pritam Bhowmik Pravat Kumar Rout Electrical Engineering Department Siksha‘O’Anusandhan UniversityBhubaneswar751030India Electrical and Electronics Engineering Department Siksha‘O’Anusandhan UniversityBhubaneswar751030India

Recently microgrids have drawn a potential attraction by fulfilling the environmental demands and the increasing energy demands of the end-users. It is necessary to focus on various protection and control aspects of a microgrid. During the transition between the grid-following and grid-forming modes, the voltage and the frequency instability due to the power mismatch condition becomes the major point of concern. Therefore, the paper executes a frequency-active power and voltage-reactive power drooping control strategy for the precise power-sharing among the distributed power generators. Furthermore, to handle the power deficit scenarios and to maintain the system stability, a system independent and priority-based adaptive three-stage load shedding strategy is proposed. The sensitivity of the strategy depends on the system inertia and is computed according to the varying absolute rate-of-change-of-frequency. The strategy incorporates the operation of battery storage system and distributed static compensator (D-STATCOM) in the microgrid, to provide a reliable power supply to the customers for a considerable time instead of a sudden load shedding. The effectiveness of the proposed strategies is investigated on a scaled-down modified IEEE 13-bus microgrid system on the podium of MATLAB 2015b through the time-domain simulation.

关键词： Microgrid Power-sharing Load shedding High inertia distributed generators Inertia-less distributed generators Battery storage system D-STATCOM

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Jeans Instability of Self Gravitating Dust Cloud in Presence of Effective Electrostatic Pressure

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Communications in Theoretical Physics 2018年第8期69卷 209-214页

作者： Pratikshya Bezbaruah pritam Das Prathana Borah Nilakshi Das Department of Physics Tezpur University

The role of viscosity coefficient(η′), coulomb coupling parameter(Γ) and dust mass on the growth of jeans mode is investigated in strongly coupled dusty plasma using equations of Generalized Hydrodynamics(GH) Model. The novel aspect of this work is that the force arising due to electrostatic pressure caused by grain grain interaction has been included in the dynamics of dust particles. This force is found to play a significant role in counter balancing the self gravity effect, thereby reducing the growth rate of jeans instability. The present work may provide more physical insight in understanding the mechanisms behind formation of planetesimals, stars etc.

关键词： generalized hydrodynamics model interstellar medium planetesimal

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Effect of B_(2)O_(3) enrichment on microstructural inhomogeneity of high strength steel weldments

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China Welding 2024年第3期33卷 25-32页

作者： Joydeep Roy pritam Das Department of Mechanical Engineering National Institute of Technology AgartalaTripura 799035India

The present work attributes the role of boron on the high strength steel submerged arc weld using an undermatching filler *** steel filler wire was used for welding in constant machine parameters setting to evaluate the joint strength due to the enrichment of *** change the chemical composition of the weld metal,boron trioxide powder was blended with virgin flux in various proportions(2.5%−12.5%),which led to an increase in boron weight percentage in the range of 0−*** results show that weld metals(WM)optical micrographs depict the various types of ferrites,pearlites and secondary phases like martensite-austenite(M-A).Acicular ferrite content was influenced by the boron trioxide *** affected zone(HAZ)micrographs were not showing appreciable changes with oxide *** and toughness of weld metals showed the mixed trend with B_(2)O_(3) enrichment whereas,small reduction in ultimate tensile strength(UTS)and yield strength(YS)was observed.

关键词： high strength steel B_(2)O_(3) flux microstructure hardness toughness ultimate tensile strength

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Facile Development of Iron-Platinum Nanoparticles to Harness Multifunctionality in Single Entity

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Acta Metallurgica Sinica(English Letters) 2016年第12期29卷 1098-1106页

作者： Madhulekha Gogoi Komanduri S. Varadarajan Anant Bahadur Patel pritam Deb Department of Physics Tezpur University (Central University) Tezpur Assam 784028 India NMR Microimaging and Spectroscopy Centre for Cellularand Molecular Biology Habsiguda Hyderabad 500007 India Department of Chemistry IIT GuwahatiNorth Guwahati Assam 781039 India

Engineered magnetic nanosystems exhibit attractive options for implementing unique diagnostic options and therapeutic solutions in biomedical applications. Here we report a facile, thermo-free and aqueous synthetic method to prepare ascorbic acid-stabilized iron-platinum nanoparticles. The effects of reducing agent, pH and sequence of precursor addition are investigated, and optimized reaction condition is identified to obtain a unique iron-platinum （Pt-FePt） nanosystems. The multifunctionality of the developed nanosystem has been realized by catalytic efficiency of platinum for therapeutic application and superparamagnetic property of FePt for magnetic resonance imaging contrast enhancement. Moreover, the multifunctional imaging and therapeutic activities have been achieved at physiological pH. The developed multifunctional nanoparticles are monodisperse with uniform morphology as well as stable in solution and non-toxic.

关键词： Multifunctional Superparamagnetic Magnetic resonance imaging (MRI) Therapeutic

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Resistance and resilience of soil biological indicators:A case study with multi-walled carbon nanotube

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Pedosphere 2024年第3期34卷 664-675页

作者： Shagufta YASMEEN Nintu MANDAL Anupam DAS pritam GANGULY Sanjay KUMAR Rajiv RAKSHIT Department of Soil Science and Agricultural Chemistry Bihar Agricultural UniversitySabourBhagalpur 813210(India) Department of Agronomy Bihar Agricultural UniversitySabourBhagalpur 813210(India)

Soil ecosystem is experiencing stresses due to climate change,and soil inhabitants try to demonstrate their inherent resistance and resilience against those *** of nanomaterials as agricultural inputs could bring shifts in resistance and resilience patterns of soil microbes and associated enzymes,especially under short-term heat *** this background,the impacts of multi-walled carbon nanotube(MWCNT)on the resistance and resilience of soil biological indicators were *** incubation experiment was conducted with varied MWCNT concentrations(0,50,100,250,and 500 mg kg-1soil)for 90 d after 24-h heat stress at 48±2?C to assess the impacts of MWCNT on soil enzyme activities and microbial populations vis-à-vis their resistance and resilience indices under short-term exposure to heat *** activities were reduced after exposure to heat *** indices of enzyme activities were enhanced by MWCNT application on day 1 after heat stress,whereas there was no recovery of enzyme activities after 90-d *** soil enzyme activities,resistance index values of soil microbial populations followed the similar trend and were improved by MWCNT ***-walled carbon nanotube has the potential to improve resistance indices of soil enzyme activities and microbial populations under heat stress,although they could not recover to their original state during periodical incubation after heat *** study helps to understand the relative changes of biological indicators under MWCNT and their ability to withstand heat stress.

关键词： enzyme activity heat stress microbial population nanomaterial recovery

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