Preparation of CdS/BiOCl/Bi₂O₃ double composite system for visible light active photocatalytic applications

Chakraborty, Ashok Kumar,Ganguli, Sumon,Bera, Sandipan,Lee, Wan In Elsevier 2018 Journal of photochemistry and photobiology Chemist Vol.364 No.-

<P><B>Abstract</B></P> <P>An efficient visible-light-harvesting (λ ≥ 420 nm) three component system heterojunction photocatalyst, CdS/BiOCl/Bi<SUB>2</SUB>O<SUB>3</SUB> was prepared by anchoring of CdS nanoparticles on the surface of BiOCl/Bi<SUB>2</SUB>O<SUB>3</SUB> composite. The effect of CdS nanoparticles on the surface of BiOCl/Bi<SUB>2</SUB>O<SUB>3</SUB> composite photocatalyst had been justified in enhancing photocatalytic activity towards the degradation of organic pollutants in gas as well as aqueous phase. With the loading of CdS on to the BiOCl/Bi<SUB>2</SUB>O<SUB>3</SUB> heterojunction composite photocatalyst, the photocatalytic activity of the CdS/BiOCl/Bi<SUB>2</SUB>O<SUB>3</SUB> composite structure has been appreciably improved for the decomposition of 2-propanol (IPA) in gas phase and salicylic acid (SA) in aqueous phase under visible light irradiation (λ ≥ 420 nm). The amount of loading of CdS nanoparticles was optimized to 2 mol% CdS/BiOCl/Bi<SUB>2</SUB>O<SUB>3</SUB>. Compare to bare BiOCl/Bi<SUB>2</SUB>O<SUB>3</SUB> photocatalyst, CdS/BiOCl/Bi<SUB>2</SUB>O<SUB>3</SUB> heterojunction demonstrated 2 times decomposition of IPA in gas phase and 1.8 times of SA in aqueous phase after 120 min. of visible light irradiation. At the same time, with this composition the evolution of CO<SUB>2</SUB> from degradation of IPA was 1.9 times higher than that of BiOCl/Bi<SUB>2</SUB>O<SUB>3</SUB> composite. The enhanced photocatalytic efficiency is deduced from the electron (eˉ) and hole (h<SUP>+</SUP>) transfer among the component semiconductor nanoparticles Bi<SUB>2</SUB>O<SUB>3</SUB>, BiOCl and CdS due to their relative energy band positions. Several experimental evidences were also provided to confirm the electron-hole transfer among the semiconductors and a mechanistic way has been proposed.</P> <P><B>Highlights</B></P> <P> <UL> <LI> CdS has been successfully anchored on to the surface of BiOCl/Bi<SUB>2</SUB>O<SUB>3</SUB> composite photocatalyst. </LI> <LI> CdS/BiOCl/Bi<SUB>2</SUB>O<SUB>3</SUB> composite photocatalyst demonstrated higher absorption towards visible light. </LI> <LI> Recombination of photoexcited electrons (e<SUP>−</SUP>) and holes (h<SUP>+</SUP>) has been effectively inhibited. </LI> <LI> Photoinduced hole (h<SUP>+</SUP>) and hydroxyl radical (OH) has been experimentally proved. </LI> <LI> Photocatalytic activity has been remarkably enhanced under visible light. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

UNIQUE RANGE SETS WITHOUT FUJIMOTO'S HYPOTHESIS

Chakraborty, Bikash Korean Mathematical Society 2022 대한수학회보 Vol.59 No.5

This paper studies the uniqueness of two non-constant meromorphic functions when they share a finite set. Moreover, we will give an existence of unique range sets for meromorphic functions that are the zero sets of some polynomials that do not necessarily satisfy the Fujimoto's hypothesis ([6]).

Edwards polaron formation : From one to three dimensions

Chakraborty, M.,Mohanta, N.,Taraphder, A.,Min, B. I.,Fehske, H. American Physical Society 2016 Physical Review B Vol.93 No.15

<P>Employing a self-consistent (optimized) variational diagonalization scheme, we investigate the formation of polaronic quasiparticles in a spinless fermion-boson transport model that couples the movement of charge carriers to fluctuations and correlations of a background medium. The background is parameterized by bosonic degrees of freedom. The variational fermion-boson Hilbert space is constructed to achieve high accuracy in one to three spatial dimensions with modest computational requirements. To characterize the ground-state properties of the Edwards model in the single-particle sector, we present exact numerical results for the polaron band dispersion, quasiparticle weight, Drude weight, mass enhancement, and the particle-boson correlations in a wide parameter regime. In the Edwards model, transport will be quasifree, diffusive or boson-assisted in the weakly fermion-boson coupled, fluctuation-dominated or strongly correlated regimes, respectively. Thereby correlated transport is not only assisted but also limited by the bosonic excitations. As a result, the Drude weight remains finite even in the limit of very small boson frequencies. For a strongly correlated background, closed loops are important, in any dimension, to generate a finite effective particle mass even when the free fermion has an infinite mass.</P>

Micro-Environmental Signature of The Interactions between Druggable Target Protein, Dipeptidyl Peptidase-IV, and Anti-Diabetic Drugs

Chakraborty, Chiranjib,Mallick, Bidyut,Sharma, Ashish Ranjan,Sharma, Garima,Jagga, Supriya,Doss, C George Priya,Nam, Ju-Suk,Lee, Sang-Soo Royan Institute 2017 Cell journal (Yakhteh) Vol.19 No.1

<P><B>Objective</B></P><P> Druggability of a target protein depends on the interacting micro-environment between the target protein and drugs. Therefore, a precise knowledge of the interacting micro-environment between the target protein and drugs is requisite for drug discovery process. To understand such micro-environment, we performed in silico interaction analysis between a human target protein, Dipeptidyl Peptidase-IV (DPP-4), and three anti-diabetic drugs (saxagliptin, linagliptin and vildagliptin). </P><P><B>Materials and Methods</B></P><P> During the theoretical and bioinformatics analysis of micro-environmental properties, we performed drug-likeness study, protein active site predictions, docking analysis and residual interactions with the protein-drug interface. Micro-environmental landscape properties were evaluated through various parameters such as binding energy, intermolecular energy, electrostatic energy, van der Waals’+H-bond+desolvo energy (E<SUB>VHD</SUB>) and ligand efficiency (LE) using different in silico methods. For this study, we have used several servers and software, such as Molsoft prediction server, CASTp server, AutoDock software and LIGPLOT server. </P><P><B>Results</B></P><P> Through micro-environmental study, highest log P value was observed for linagliptin (1.07). Lowest binding energy was also observed for linagliptin with DPP-4 in the binding plot. We also identified the number of H-bonds and residues involved in the hydrophobic interactions between the DPP-4 and the anti-diabetic drugs. During interaction, two H-bonds and nine residues, two H-bonds and eleven residues as well as four H-bonds and nine residues were found between the saxagliptin, linagliptin as well as vildagliptin cases and DPP-4, respectively. </P><P><B>Conclusion</B></P><P>Our in silico data obtained for drug-target interactions and micro-environmental signature demonstrates linagliptin as the most stable interacting drug among the tested anti-diabetic medicines.</P>

Genome-wide identification, characterization, and expression profiling of 14-3-3 genes in legumes

Chakraborty Srija,Soudararajan Prabhakaran,Kumar Shailesh 한국식물생명공학회 2022 Plant biotechnology reports Vol.16 No.5

In plants, a large multigene family encodes 14-3-3 proteins, which are commonly found in eukaryotes. They are involved in plant development and environmental stress regulation. The current study aims to identify and characterize the 14-3-3 gene family in four important legumes, viz. Cicer arietinum, Cajanus cajan, Vigna radiata and Arachis hypogaea. The 14-3-3 proteins were clustered into ε and non-ε groups based on phylogenetic analysis, which was further confirmed by gene struc- ture analysis, and motif composition analysis. Our study suggests that segmental duplication events played a pivotal role in the evolution and expansion of this gene family. Evidence of both stress-responsive, and hormone-responsive cis-regulatory elements in the promoter region of the 14-3-3 genes points to the possibility that they might be involved in the interplay between hormone and stress signalling pathways. The expression profiling using RNA-seq data sets showed a variation in expression level in most 14-3-3 genes under multiple stress conditions, and in different developmental stages. Hence, this study affirms the participation of the 14-3-3 genes in multiple stress regulation, and in growth and development of the legumes. The results obtained from this study provide crucial information for improved understanding, and stress response analysis of the 14-3-3 gene family in C. arietinum, C. cajan, V. radiata and A. hypogaea.

Interacting-Holstein and extended-Holstein bipolarons

Chakraborty, Monodeep,Tezuka, Masaki,Min, B. I. American Physical Society 2014 Physical review. B, Condensed matter and materials Vol.89 No.3

Employing the recently developed self-consistent variational basis generation scheme, we have investigated the bipolaron-bipolaron interaction within the purview of the Holstein-Hubbard and the extended-Holstein-Hubbard (F2H) models on a discrete one-dimensional lattice. The density-matrix renormalization group method has also been used for the Holstein-Hubbard model. We have shown that there exists no bipolaron-bipolaron attraction in the Holstein-Hubbard model. In contrast, we have obtained clear-cut bipolaron-bipolaron attraction in the F2H model. Composite bipolarons are formed above a critical electron-phonon coupling strength, which can survive the finite Hubbard U effect. We have constructed the phase diagram of F2H polarons and bipolarons, and discussed the phase separation in terms of the formation of composite bipolarons.

Stability of Holstein and Fröhlich bipolarons

Chakraborty, Monodeep,Min, B. I.,Chakrabarti, Atisdipankar,Das, A. N. American Physical Society 2012 Physical review. B, Condensed matter and materials Vol.85 No.24

Analysis of regeneration protocols for micropropagation of Pterocarpus santalinus

Chakraborty Tanushree,Chaitanya K. Viswanatha,Akhtar Nasim 한국식물생명공학회 2022 Plant biotechnology reports Vol.16 No.1

A micropropagation is a powerful tool in the era of the biotechnology revolution. It has a broad range of potentiality as compared to conventional vegetative propagation attracting researchers, industrialists, governmental and nongovernmental organizations at the national and international level. The potential methods of organogenesis and somatic embryogenesis, primarily through callogenesis, allow the production of genotypically identical and pharmacologically conserved disease- free healthy stocks in shorter times. Pterocarpus santalinus, the pride of Andhra Pradesh, has become endangered due to medicinal and commercial overexploitation. The micropropagation of P. santalinus poses many cultural challenges due to limited regeneration potential through callogenesis, organogenesis, and somatic embryogenesis. The lack of proper explant treatment and the effect of plant growth regulators limit the application of published protocols to reproduce the results. The challenge, such as heavy contamination of mature explants with endophytic fungi, forced us to explore the potential of immature tissues for regeneration through induction of somatic embryogenesis. We observed that immature tissues (zygotic embryo, petal, ovary, and anther) are better responsive than mature tissues with the scantiest contamination and phenolic release. The present study analyzed, evaluated, and interpreted the different parameters applied in the micropropagation of P. santalinus. The aim is to solve the discrepancies of existing protocols to present complete insight for future needs in the successful regeneration of the species. The review also compared various treatments to overcome dormancy and promote germination. It also discussed the possibilities of induction of somatic embryogenesis for future research.

Photocatalytic Behavior of WO₃/TiO₂ in Decomposing Volatile Aldehydes

Chakraborty, Ashokkumar,Chai, Seung-Yong,Lee, Wan-In Korean Chemical Society 2008 Bulletin of the Korean Chemical Society Vol.29 No.2

Wind load on irregular plan shaped tall building - a case study

Chakraborty, Souvik,Dalui, Sujit Kumar,Ahuja, Ashok Kumar Techno-Press 2014 Wind and Structures, An International Journal (WAS Vol.19 No.1

This paper presents the results of wind tunnel studies and numerical studies on a '+' plan shaped tall building. The experiment was carried out in an open circuit wind tunnel on a 1:300 scale rigid model. The mean wind pressure coefficients on all the surfaces were studied for wind incidence angle of $0^{\circ}$ and $45^{\circ}$. Certain faces were subjected to peculiar pressure distribution due to irregular formation of eddies caused by the separation of wind flow. Moreover, commercial CFD packages of ANSYS were used to demonstrate the flow pattern around the model and pressure distribution on various faces. k-${\varepsilon}$ and SST viscosity models were used for numerical study to simulate the wind flow. Although there are some differences on certain wall faces, the numerical result is having a good agreement with the experimental results for both wind incidence angle.