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Kumaravel A, Selvamani V, Sengupta T, Gu Kang S, Ho Hong S. Surface engineered recombinant Escherichia coli for the potential application of the cobalt contaminated wastewater treatment and the photocatalytic dye degradation. Bioresour Technol 2024:130796. [PMID: 38703957 DOI: 10.1016/j.biortech.2024.130796] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/18/2024] [Revised: 04/17/2024] [Accepted: 05/02/2024] [Indexed: 05/06/2024]
Abstract
The novel recombinant Escherichia coli strain was construct through cell surface display for the treatment of cobalt contaminated wastewater and dye contaminated wastewater. First, structural analysis of known cobalt binding peptide was conducted and core binding sites were figured out which showing better cobalt binding ability. The cobalt peptides were attached to OmpC to construct cobalt adsorbing recombinant Escherichia coli. The recombinant strain efficiently absorbed and retrieved cobalt from cobalt wastewater by adsorbing 1895 µmol/g DCW of cobalt. Following adsorption, cobalt nanoparticles were synthesized through thermal decomposition of cobalt adsorbed recombinant strain at 500˚C. The nanoparticles exhibited noteworthy photocatalytic properties, demonstrating a substantial capacity for degrading dyes when used as a catalyst at a concentration of 10 mg/dl. These results presenting potential solutions for effective and environmentally friendly approaches to address cobalt and dye contaminated wastewater treatment process.
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Affiliation(s)
- Ashokkumar Kumaravel
- Department of Chemical Engineering, University of Ulsan, 93 Daehak-ro, Nam-gu, Ulsan 44610, Republic of Korea
| | - Vidhya Selvamani
- Department of Chemical Engineering, University of Ulsan, 93 Daehak-ro, Nam-gu, Ulsan 44610, Republic of Korea
| | - Turbasu Sengupta
- Department of Chemical Engineering, University of Ulsan, 93 Daehak-ro, Nam-gu, Ulsan 44610, Republic of Korea
| | - Sung Gu Kang
- Department of Chemical Engineering, University of Ulsan, 93 Daehak-ro, Nam-gu, Ulsan 44610, Republic of Korea
| | - Soon Ho Hong
- Department of Chemical Engineering, University of Ulsan, 93 Daehak-ro, Nam-gu, Ulsan 44610, Republic of Korea.
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Chandrashekar P, Sardar G, Sengupta T, Reber AC, Mondal PK, Kabra D, Khanna SN, Deria P, Mandal S. Modulation of Singlet-Triplet Gap in Atomically Precise Silver Cluster-Assembled Material. Angew Chem Int Ed Engl 2024; 63:e202317345. [PMID: 38078805 DOI: 10.1002/anie.202317345] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2023] [Indexed: 12/30/2023]
Abstract
Silver cluster-based solids have garnered considerable attention owing to their tunable luminescence behavior. While surface modification has enabled the construction of stable silver clusters, controlling interactions among clusters at the molecular level has been challenging due to their tendency to aggregate. Judicious choice of stabilizing ligands becomes pivotal in crafting a desired assembly. However, detailed photophysical behavior as a function of their cluster packing remained unexplored. Here, we modulate the packing pattern of Ag12 clusters by varying the nitrogen-based ligand. CAM-1 formed through coordination of the tritopic linker molecule and NC-1 with monodentate pyridine ligand; established via non-covalent interactions. Both the assemblies show ligand-to-metal-metal charge transfer (LMMCT) based cluster-centered emission band(s). Temperature-dependent photoluminescence spectra exhibit blue shifts at higher temperatures, which is attributed to the extent of the thermal reverse population of the S1 state from the closely spaced T1 state. The difference in the energy gap (ΔEST ) dictated by their assemblies played a pivotal role in the way that Ag12 cluster assembly in CAM-1 manifests a wider ΔEST and thus requires higher temperatures for reverse intersystem crossing (RISC) than assembly of NC-1. Such assembly-defined photoluminescence properties underscore the potential toolkit to design new cluster- assemblies with tailored optoelectronic properties.
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Affiliation(s)
- Priyanka Chandrashekar
- School of Chemistry, Indian Institute of Science Education and Research Thiruvananthapuram, Kerala, 695551, India
| | - Gopa Sardar
- Department of Physics, Indian Institute of Technology Bombay Powai, Mumbai, 400076, India
| | - Turbasu Sengupta
- Department of Physics, Virginia Commonwealth University, Richmond, VA-23220, USA
| | - Arthur C Reber
- Department of Physics, Virginia Commonwealth University, Richmond, VA-23220, USA
| | - Pradip Kumar Mondal
- Elettra-Sincrotrone Trieste, S.S. 14 Km 163.5 in Area Science Park, Basovizza, 34149, Trieste, Italy
| | - Dinesh Kabra
- Department of Physics, Indian Institute of Technology Bombay Powai, Mumbai, 400076, India
| | - Shiv N Khanna
- Department of Physics, Virginia Commonwealth University, Richmond, VA-23220, USA
| | - Pravas Deria
- School of Chemical & Biomolecular Science, Southern Illinois University, 1245 Lincoln Drive, Carbondale, IL-62901, USA
| | - Sukhendu Mandal
- School of Chemistry, Indian Institute of Science Education and Research Thiruvananthapuram, Kerala, 695551, India
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R D, Sengupta T, Kumar D, Khanna SN. Effect of Ligand Attachment at Ag 11 for CO Oxidation: A Computational Investigation. J Phys Chem A 2023; 127:10766-10774. [PMID: 38095876 DOI: 10.1021/acs.jpca.3c04675] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2023]
Abstract
Heterogeneous CO oxidation is a demanding reaction at room temperature due to the high activation energy required to break the O=O bond. While several metal clusters are reported to oxidize CO successfully, they fall short of their selectivity for the reaction and recyclability. In this regard, there is a need for economic catalysts with high catalytic activity, low activation barrier, and reusability. In this study, we have investigated the catalytic activity of the neutral pristine and ligated Ag11 cluster toward CO oxidation. We investigated the attachment effect of three organic donor ligands: trimethylphosphine, triethylphosphine, and N-ethyl pyrrolidone to the Ag11 cluster. Our results show that including donor ligands on the Ag11 cluster surface can significantly reduce the barrier heights for CO oxidation. The minimum barrier heights with the system coordinated with triethylphosphine showed the lowest activation barrier of 1.06 kcal/mol compared to the high activation barrier of 14.77 kcal/mol recorded for the pristine cluster. Exploration of the reaction mechanism and charge analysis showed that the electron donor ligands activate O2 via charge donation, thereby reducing the barrier heights of CO oxidation.
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Affiliation(s)
- Deeksha R
- Department of Chemistry, Faculty of Mathematical and Physical Sciences, M.S. Ramaiah University of Applied Sciences, Bengaluru, Karnataka 560058, India
| | - Turbasu Sengupta
- Physics Department, Virginia Commonwealth University, 701 W. Grace St., Richmond, Virginia 23284-2000, United States
| | - Deepak Kumar
- Department of Chemistry, Faculty of Mathematical and Physical Sciences, M.S. Ramaiah University of Applied Sciences, Bengaluru, Karnataka 560058, India
| | - Shiv N Khanna
- Physics Department, Virginia Commonwealth University, 701 W. Grace St., Richmond, Virginia 23284-2000, United States
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Geng L, Sengupta T, Li X, Cui C, Lin S, Xu XL, Reber AC, Khanna SN, Zheng WJ, Luo Z. Unusually High-Spin Fe 12C 12- Metallo-Carbohedrene Clusters. J Am Chem Soc 2023. [PMID: 38041728 DOI: 10.1021/jacs.3c09690] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2023]
Abstract
Ferromagnets constructed from nanometals of atomic precision are important for innovative advances in information storage, energy conversion, and spintronic microdevices. Considerable success has been achieved in designing molecular magnets, which, however, are challenging in preparation and may suffer from drawbacks on the incompatibility of high stability and strong ferromagnetism. Utilizing a state-of-the-art self-developed mass spectrometer and a homemade laser vaporization source, we have achieved a highly efficient preparation of pure iron clusters, and here, we report the finding of a strongly ferromagnetic metal-carbon cluster, Fe12C12-, simply by reacting the Fen- clusters with acetylene in proper conditions. The unique stability of this ferromagnetic Fe12C12- cluster is rooted in a plumb-bob structure pertaining to Jahn-Teller distortion. We classify Fe12C12- as a new member of metallo-carbohedrenes and elucidate its structural stability mechanism as well as its soft-landing deposition and magnetization measurements, providing promise for the exploration of potential applications.
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Affiliation(s)
- Lijun Geng
- Beijing National Laboratory for Molecular Sciences (BNLMS), State Key Laboratory for Structural Chemistry of Unstable and Stable Species, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
| | - Turbasu Sengupta
- Department of Physics, Virginia Commonwealth University, Richmond, Virginia 23284-2000, United States
| | - Xilong Li
- State Key Laboratory of Molecular Reaction Dynamics, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
| | - Chaonan Cui
- Beijing National Laboratory for Molecular Sciences (BNLMS), State Key Laboratory for Structural Chemistry of Unstable and Stable Species, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
| | - Shiquan Lin
- Beijing National Laboratory for Molecular Sciences (BNLMS), State Key Laboratory for Structural Chemistry of Unstable and Stable Species, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
| | - Xi-Ling Xu
- State Key Laboratory of Molecular Reaction Dynamics, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
| | - Arthur C Reber
- Department of Physics, Virginia Commonwealth University, Richmond, Virginia 23284-2000, United States
| | - Shiv N Khanna
- Department of Physics, Virginia Commonwealth University, Richmond, Virginia 23284-2000, United States
| | - Wei-Jun Zheng
- State Key Laboratory of Molecular Reaction Dynamics, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
- School of Chemical Science, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Zhixun Luo
- Beijing National Laboratory for Molecular Sciences (BNLMS), State Key Laboratory for Structural Chemistry of Unstable and Stable Species, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
- School of Chemical Science, University of Chinese Academy of Sciences, Beijing 100049, China
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Sengupta T, Khanna SN. Converting CO 2 to formic acid by tuning quantum states in metal chalcogenide clusters. Commun Chem 2023; 6:53. [PMID: 36941466 PMCID: PMC10027883 DOI: 10.1038/s42004-023-00851-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2022] [Accepted: 03/07/2023] [Indexed: 03/23/2023] Open
Abstract
The catalytic conversion of CO2 into valuable chemicals is an effective strategy for reducing its adverse impact on the environment. In this work, the formation of formic acid via CO2 hydrogenation on bare and ligated Ti6Se8 clusters is investigated with gradient-corrected density functional theory. It is shown that attaching suitable ligands (i.e., PMe3, CO) to a metal-chalcogenide cluster transforms it into an effective donor/acceptor enabling it to serve as an efficient catalyst. Furthermore, by controlling the ratio of the attached donor/acceptor ligands, it is possible to predictably alter the barrier heights of the CO2 hydrogenation reaction and, thereby, the rate of CO2 conversion. Our calculation further reveals that by using this strategy, the barrier heights of CO2 hydrogenation can be reduced to ~0.12 eV or possibly even lower, providing unique opportunities to control the reaction rates by using different combinations of donor/acceptor ligands.
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Affiliation(s)
- Turbasu Sengupta
- Department of Physics, Virginia Commonwealth University, Richmond, VA, 23284-2000, USA.
| | - Shiv N Khanna
- Department of Physics, Virginia Commonwealth University, Richmond, VA, 23284-2000, USA.
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Reber AC, Sengupta T, Bista D, Khanna SN. Magic Numbers in Octahedral Ligated Metal-Chalcogenide Superatoms. Inorg Chem 2022; 61:16003-16008. [PMID: 36149274 DOI: 10.1021/acs.inorgchem.2c02361] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The attainment of the superatomic state offers a unifying framework for the periodic classification of atomic clusters. Metallic clusters attain the superatomic state via the confined nearly free electron gas model that leads to groupings of quantum states marked by radial and angular momentum quantum numbers. We examine ligated octahedral metal-chalcogenide clusters where the nearly free electron gas model is invalid; however, the high symmetry can also lead to the bunching of electronic states. For octahedral TM6E8L6 clusters (TM = transition metal; E = chalcogen; L = ligand), the electronic shells are filled for valence electron counts of 96, 100, and 114 electrons. These magic electron counts are marked by large highest occupied molecular orbital-lowest unoccupied molecular orbital (HOMO-LUMO) gaps, high ionization energies, and low electron affinity─all classic signatures of the superatomic state. We also find that clusters with electron counts differing from the magic counts show periodic patterns reminiscent of those observed in the periodic table of elements.
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Affiliation(s)
- Arthur C Reber
- Department of Physics, Virginia Commonwealth University, Richmond, Virginia 23284-2000, United States
| | - Turbasu Sengupta
- Department of Physics, Virginia Commonwealth University, Richmond, Virginia 23284-2000, United States
| | - Dinesh Bista
- Department of Physics, Virginia Commonwealth University, Richmond, Virginia 23284-2000, United States
| | - Shiv N Khanna
- Department of Physics, Virginia Commonwealth University, Richmond, Virginia 23284-2000, United States
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7
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Sengupta T, Khanna SN. Rational Design of Bimetallic Metal Chalcogenide Clusters for CO 2 Dissociation. J Phys Chem A 2022; 126:5702-5710. [PMID: 35973159 DOI: 10.1021/acs.jpca.2c03560] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Thermochemical dissociation of CO2 on pure, ligated, and mixed transition metal (W, Cu) chalcogenide clusters are investigated using the first-principles gradient-corrected density functional approach. It is shown that although the pure and ligated metal chalcogenide clusters exhibit significantly high barriers for CO2 dissociation, the computed barriers for the mixed clusters are relatively lower. The lowest barrier is obtained for the Cu3W3Se8 cluster, which shows a dramatically reduced barrier height of only 0.41 eV. Detailed analysis reveals that the substitution of W by Cu sites leads to a charge transfer from Cu to W sites, resulting in locally active W sites. The lowering of the CO2 dissociation barriers can be attributed to the facile transfer of charge from the locally active W sites and also due to the alteration of the binding energy of CO2 to the charged W sites. Our studies provide an alternate strategy to design novel thermochemical catalysts for CO2 adsorption and subsequent dissociation.
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Affiliation(s)
- Turbasu Sengupta
- Department of Physics, Virginia Commonwealth University, Richmond, Virginia 23284-2000, United States
| | - Shiv N Khanna
- Department of Physics, Virginia Commonwealth University, Richmond, Virginia 23284-2000, United States
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Shen J, He H, Sengupta T, Bista D, Reber AC, Pandey R, Khanna SN. Electron transport properties of PAl 12-based cluster complexes. Nanoscale Adv 2021; 3:6888-6896. [PMID: 36132360 PMCID: PMC9418132 DOI: 10.1039/d1na00355k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/15/2021] [Accepted: 09/10/2021] [Indexed: 06/15/2023]
Abstract
The electronic transport properties of PAl12-based cluster complexes are investigated by density functional theory (DFT) in combination with the non-equilibrium Green's function (NEGF) method. Joining two PAl12 clusters via a germanium linker creates a stable semiconducting complex with a large HOMO-LUMO gap. Sequential attachment of an electron-donating ligand, N-ethyl-2-pyrrolidone, to one of the two linked clusters results in the shifting of the electronic spectrum of the ligated cluster while the energy levels of the unligated cluster are mostly unchanged. Using this approach, one can eventually align the HOMO of the ligated cluster to the LUMO of the non-ligated cluster, thereby significantly reducing the HOMO-LUMO gap of the complex. As a result, the transport properties of the complex are highly dependent on the number of attached ligands. Although a single ligand is observed to generally decrease the current, the inclusion of two or more ligands shows a significant increase in the amount of current at most voltages. The resulting increase of the current can be attributed to two factors, first the reduction in the HOMO-LUMO gap due to ligand attachment which has moved the transmission orbitals into the bias window. Secondly, when two or more ligands are attached to the complex, the HOMOs become delocalized across the scattering region, and this significantly enhances the currents.
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Affiliation(s)
- John Shen
- Department of Physics and Astronomy, Valparaiso University Valparaiso Indiana 46383 USA
| | - Haiying He
- Department of Physics and Astronomy, Valparaiso University Valparaiso Indiana 46383 USA
| | - Turbasu Sengupta
- Department of Physics, Virginia Commonwealth University Richmond Virginia 23284 USA
| | - Dinesh Bista
- Department of Physics, Virginia Commonwealth University Richmond Virginia 23284 USA
| | - Arthur C Reber
- Department of Physics, Virginia Commonwealth University Richmond Virginia 23284 USA
| | - Ravindra Pandey
- Department of Physics, Michigan Technological University Houghton Michigan 49931 USA
| | - Shiv N Khanna
- Department of Physics, Virginia Commonwealth University Richmond Virginia 23284 USA
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Bista D, Sengupta T, Reber AC, Khanna SN. Interfacial magnetism in a fused superatomic cluster [Co 6Se 8(PEt 3) 5] 2. Nanoscale 2021; 13:15763-15769. [PMID: 34528648 DOI: 10.1039/d1nr00876e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
An isolated Co6Se8(PEt3)6 cluster is non-magnetic; however, we find that a magnetic unit can be formed by fusing two Co6Se8(PEt3)5 superatoms into a [Co6Se8(PEt3)5]2 dimer. Theoretical studies indicate that the dumbbell-shaped [Co6Se8(PEt3)5]2 dimer has a spin moment of 2μB, and the spin density is primarily localized at the interfacial Co-sites where two clusters are fused into a dimer. The dimer has a low ionization energy of 4.17 eV, allowing the dimer to donate charge to C70 during the formation of a cluster assembled material, as seen in recent experiments by Nuckolls and co-workers. The donation of charge causes the dimer's magnetic moment to drop from 2μB to 1μB. We hypothesize that adding electrons to the dimer, such as doping impurities to the crystal lattice, may enhance the magnetic moment by neutralizing the charged cluster. This reveals a strategy for stabilizing magnetic moments in ligated cluster assemblies.
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Affiliation(s)
- Dinesh Bista
- Department of Physics, Virginia Commonwealth University, Richmond, VA, 23284-2000, USA.
| | - Turbasu Sengupta
- Department of Physics, Virginia Commonwealth University, Richmond, VA, 23284-2000, USA.
| | - Arthur C Reber
- Department of Physics, Virginia Commonwealth University, Richmond, VA, 23284-2000, USA.
| | - Shiv N Khanna
- Department of Physics, Virginia Commonwealth University, Richmond, VA, 23284-2000, USA.
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Khanna SN, Reber AC, Bista D, Sengupta T, Lambert R. The superatomic state beyond conventional magic numbers: Ligated metal chalcogenide superatoms. J Chem Phys 2021; 155:120901. [PMID: 34598575 DOI: 10.1063/5.0062582] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The field of cluster science is drawing increasing attention due to the strong size and composition-dependent properties of clusters and the exciting prospect of clusters serving as the building blocks for materials with tailored properties. However, identifying a unifying central paradigm that provides a framework for classifying and understanding the diverse behaviors is an outstanding challenge. One such central paradigm is the superatom concept that was developed for metallic and ligand-protected metallic clusters. The periodic electronic and geometric closed shells in clusters result in their properties being based on the stability they gain when they achieve closed shells. This stabilization results in the clusters having a well-defined valence, allowing them to be classified as superatoms-thus extending the Periodic Table to a third dimension. This Perspective focuses on extending the superatomic concept to ligated metal-chalcogen clusters that have recently been synthesized in solutions and form assemblies with counterions that have wide-ranging applications. Here, we illustrate that the periodic patterns emerge in the electronic structure of ligated metal-chalcogenide clusters. The stabilization gained by the closing of their electronic shells allows for the prediction of their redox properties. Further investigations reveal how the selection of ligands may control the redox properties of the superatoms. These ligated clusters may serve as chemical dopants for two-dimensional semiconductors to control their transport characteristics. Superatomic molecules of multiple metal-chalcogen superatoms allow for the formation of nano-p-n junctions ideal for directed transport and photon harvesting. This Perspective outlines future developments, including the synthesis of magnetic superatoms.
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Affiliation(s)
- Shiv N Khanna
- Department of Physics, Virginia Commonwealth University, Richmond, Virginia 23284-2000, USA
| | - Arthur C Reber
- Department of Physics, Virginia Commonwealth University, Richmond, Virginia 23284-2000, USA
| | - Dinesh Bista
- Department of Physics, Virginia Commonwealth University, Richmond, Virginia 23284-2000, USA
| | - Turbasu Sengupta
- Department of Physics, Virginia Commonwealth University, Richmond, Virginia 23284-2000, USA
| | - Ryan Lambert
- Department of Physics, Virginia Commonwealth University, Richmond, Virginia 23284-2000, USA
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Bista D, Sengupta T, Khanna SN. Massive dipoles across the metal-semiconductor cluster interface: towards chemically controlled rectification. Phys Chem Chem Phys 2021; 23:18975-18982. [PMID: 34612436 DOI: 10.1039/d1cp02420e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
An interface between a metallic cluster (MgAl12) and a semiconducting cluster (Re6Se8(PMe3)5) is shown to be marked by a massive dipole reminiscent of a dipolar layer leading to a Schottky barrier at metal-semiconductor interfaces. The metallic cluster MgAl12 with a valence electron count of 38 electrons is two electrons short of 40 electrons needed to complete its electronic shells in a superatomic model and is marked by a significant electron affinity of 2.99 eV. On the other hand, the metal-chalcogenide semiconducting cluster Re6Se8(PMe3)5, consisting of a Re6Se8 core ligated with five trimethylphosphine ligands, is highly stable in the +2 charge-state owing to its electronic shell closure, and has a low ionization energy of 3.3 eV. The composite cluster Re6Se8(PMe3)5-MgAl12 formed by combining the MgAl12 cluster through the unligated site of Re6Se8(PMe3)5 exhibits a massive dipole moment of 28.38 D resulting from a charge flow from Re6Se8(PMe3)5 to the MgAl12 cluster. The highest occupied molecular orbital (HOMO) of the composite cluster is on the MgAl12 side, which is 0.53 eV below the lowest unoccupied molecular orbital (LUMO) localized on the Re6Se8(PMe3)5 cluster, reminiscent of a Schottky barrier at metal-semiconductor interfaces. Therefore, the combination can act as a rectifier, and an application of a voltage of approximately 4.1 V via a homogeneous external electric field is needed to overcome the barrier aligning the two states: the HOMO in MgAl12 with the LUMO in Re6Se8(PMe3)5. Apart from the bias voltage, the barrier can also be reduced by attaching ligands to the metallic cluster, which provides chemical control over rectification. Finally, the fused cluster is shown to be capable of separating electron-hole pairs with minimal recombination, offering the potential for photovoltaic applications.
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Affiliation(s)
- Dinesh Bista
- Department of Physics, Virginia Commonwealth University, Richmond, VA 23284-2000, USA.
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Affiliation(s)
- Turbasu Sengupta
- Department of Physics, Virginia Commonwealth University, Richmond, Virginia 23284-2000, United States
| | - Dinesh Bista
- Department of Physics, Virginia Commonwealth University, Richmond, Virginia 23284-2000, United States
| | - Shiv N. Khanna
- Department of Physics, Virginia Commonwealth University, Richmond, Virginia 23284-2000, United States
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13
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Das AK, Maity S, Sengupta T, Bista D, Reber AC, Patra A, Khanna SN, Mandal S. One-Dimensional Silver-Thiolate Cluster-Assembly: Effect of Argentophilic Interactions on Excited-State Dynamics. J Phys Chem Lett 2021; 12:2154-2159. [PMID: 33626284 DOI: 10.1021/acs.jpclett.0c03728] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
We report the synthesis, crystal structure, and electronic structure calculations of a one-dimensional silver-thiolate cluster-assembled and its ultrafast spectroscopic investigation. Experiments and theory find the material to have a significant gap as the HOMO-LUMO absorption corresponds to 2.69 eV, and the defect-free structure is calculated to have a gap of 2.82 eV. Cluster models demonstrate that the gap energy is length-dependent. Theoretical studies identify a nonbonding metallophilic interaction that exists between two Ag atoms in adjacent strings that helps to stabilize the chain structure. Transient absorption spectroscopy reveals that the electron dynamics is a mixture of the behavior of cluster and nanoparticle, with the material having a 346 fs ground-state relaxation like a cluster, and the electron dynamics is dominated by electron-phonon coupling with a decay time of 1.5 ps, unlike the isolated cluster whose decay is mostly radiative.
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Affiliation(s)
- Anish Kumar Das
- School of Chemistry, Indian Institute of Science Education and Research Thiruvananthapuram, Thiruvananthapuram, Kerala 695551, India
| | - Subarna Maity
- School of Materials Sciences, Indian Association for the Cultivation of Science, Jadavpur, Kolkata, WB 700032, India
| | - Turbasu Sengupta
- Department of Physics, Virginia Commonwealth University, Richmond, Virginia 23220, United States
| | - Dinesh Bista
- Department of Physics, Virginia Commonwealth University, Richmond, Virginia 23220, United States
| | - Arthur C Reber
- Department of Physics, Virginia Commonwealth University, Richmond, Virginia 23220, United States
| | - Amitava Patra
- School of Materials Sciences, Indian Association for the Cultivation of Science, Jadavpur, Kolkata, WB 700032, India
| | - Shiv N Khanna
- Department of Physics, Virginia Commonwealth University, Richmond, Virginia 23220, United States
| | - Sukhendu Mandal
- School of Chemistry, Indian Institute of Science Education and Research Thiruvananthapuram, Thiruvananthapuram, Kerala 695551, India
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14
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Affiliation(s)
- Dinesh Bista
- Department of Physics, Virginia Commonwealth University, Richmond, Virginia 23284-2000, United States
| | - Turbasu Sengupta
- Department of Physics, Virginia Commonwealth University, Richmond, Virginia 23284-2000, United States
| | - Arthur C. Reber
- Department of Physics, Virginia Commonwealth University, Richmond, Virginia 23284-2000, United States
| | - Shiv N. Khanna
- Department of Physics, Virginia Commonwealth University, Richmond, Virginia 23284-2000, United States
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15
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Bista D, Chauhan V, Sengupta T, Reber AC, Khanna SN. A ligand-induced homojunction between aluminum-based superatomic clusters. Nanoscale 2020; 12:12046-12056. [PMID: 32469025 DOI: 10.1039/d0nr02611e] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
A superatomic molecule formed by joining two metallic clusters linked by an organometallic bridge can behave like a semiconductor and the addition of ligands can induce a significant energy level shift across an inter-cluster homojunction. This shift is induced by the N-ethyl-2-pyrrolidone ligands, and the placement of the ligands strongly affects the direction of the dipole moment, including the case where the dipole moment is parallel to the cluster interface. This computational study provides an alternative strategy for constructing nanometer-scale electronic interfaces between clusters mimicking semiconductor motifs. The semiconducting features in the PAl12 clusters emerge from the grouping of the quantum states in a confined nearly free electron gas that creates a substantial energy gap. An organometallic Ge(CH3)2(CH2)2 bridge links the clusters while maintaining the cluster's electronic shell structure. The amount of level shifting between the bridged clusters can be changed by controlling the number of ligands. Attaching multiple ligands can result in a broken gap energy alignment in which the HOMO level of one cluster is aligned with the LUMO level of the other bridged cluster. Furthermore, the singly ligated bridged superatomic molecule is found to exhibit promising features to separate the electron-hole pairs for photovoltaic applications.
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Affiliation(s)
- Dinesh Bista
- Department of Physics, Virginia Commonwealth University, Richmond, VA 23284-2000, USA.
| | - Vikas Chauhan
- Ramjas College, University of Delhi, Delhi-110007, India
| | - Turbasu Sengupta
- Department of Physics, Virginia Commonwealth University, Richmond, VA 23284-2000, USA.
| | - Arthur C Reber
- Department of Physics, Virginia Commonwealth University, Richmond, VA 23284-2000, USA.
| | - Shiv N Khanna
- Department of Physics, Virginia Commonwealth University, Richmond, VA 23284-2000, USA.
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Sengupta T, Chung JS, Kang SG. A mechanistic insight into rhodium-doped gold clusters as a better hydrogenation catalyst. Nanoscale 2020; 12:5125-5138. [PMID: 32073083 DOI: 10.1039/c9nr10258b] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The reaction mechanism of the hydrogenation of ethylene on pristine (Aun, n = 8 and 20) and rhodium-doped (AunRh) gold clusters was unveiled by theoretical calculations. All reaction pathways are predicted and the thermodynamic and kinetic parameters are computed and compared. Doping a rhodium atom on the magic gold cluster surface is effective in reducing the activation barriers for hydrogenation and in creating two competitive pathways with significantly higher turnover frequencies. The lower barriers of hydrogenation on the AunRh clusters were analyzed and explained based on distortion/interaction activation strain (DIAS) analysis. Further insights into the reaction mechanism on both types of clusters are provided by intrinsic bond orbital (IBO) calculations. This theoretical study provides an idea to elucidate the hydrogenation mechanism on Au clusters and the effect of the rhodium dopant on the catalytic process.
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Affiliation(s)
- Turbasu Sengupta
- School of Chemical Engineering, University of Ulsan, 93 Daehakro, Nam-Gu, Ulsan 44610, South Korea.
| | - Jin Suk Chung
- School of Chemical Engineering, University of Ulsan, 93 Daehakro, Nam-Gu, Ulsan 44610, South Korea.
| | - Sung Gu Kang
- School of Chemical Engineering, University of Ulsan, 93 Daehakro, Nam-Gu, Ulsan 44610, South Korea.
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Sengupta T, Chung JS, Kang SG. Account of chemical bonding and enhanced reactivity of vanadium-doped rhodium clusters toward C–H activation: a DFT investigation. Phys Chem Chem Phys 2019; 21:9935-9948. [DOI: 10.1039/c9cp00444k] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The chemical bonding and enhanced reactivity of vanadium-doped rhodium clusters toward C–H activation were investigated using DFT.
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Affiliation(s)
- Turbasu Sengupta
- School of Chemical Engineering
- University of Ulsan
- Ulsan 44610
- South Korea
| | - Jin Suk Chung
- School of Chemical Engineering
- University of Ulsan
- Ulsan 44610
- South Korea
| | - Sung Gu Kang
- School of Chemical Engineering
- University of Ulsan
- Ulsan 44610
- South Korea
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Sengupta T, Dang TT, Chung JS, Kang SG. Insight into the structure and bonding of copper( i) iodide clusters and a cluster-based coordination polymer. NEW J CHEM 2019. [DOI: 10.1039/c9nj02130b] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The structure and chemical bonding pattern of selected copper(i) iodide clusters and a cluster-based coordination polymer are investigated using DFT.
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Affiliation(s)
- Turbasu Sengupta
- School of Chemical Engineering
- University of Ulsan
- Ulsan 44610
- South Korea
| | - Thanh Truong Dang
- School of Chemical Engineering
- University of Ulsan
- Ulsan 44610
- South Korea
| | - Jin Suk Chung
- School of Chemical Engineering
- University of Ulsan
- Ulsan 44610
- South Korea
| | - Sung Gu Kang
- School of Chemical Engineering
- University of Ulsan
- Ulsan 44610
- South Korea
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Abstract
Low temperature oxidation of CO to CO2 is an important process for the environment. Similarly adsorption of CO from the releasing sources is also of major concern today. Whereas the potential of gold and silver clusters is well proven for the catalysis of the above mentioned reaction, the potential of aluminum (Al) clusters remains unexplored. The present study proves that, similar to the transition metals, Al clusters can also be used for adsorption of gases. We first tested the potential of Al cluster as adsorbents for CO. The high binding energy (BE) values prove that Al clusters can be used for adsorbing both CO and O2. Since oxygen binding is more facile, we adsorbed oxygen on Al and then checked the effect of this O2 on the BE of CO. The results were obtained by DFT calculations at M062X/TZVP level of theory. Graphical abstract Activation of carbon monoxide (CO) on oxygen-adsorbed aluminum (Al) cluster.
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Affiliation(s)
- Bipasa Samanta
- Department of Chemistry, Indian Institute of Technology, Powai, Mumbai, 400076, India.
| | - Turbasu Sengupta
- Physical Chemistry Division, CSIR National Chemical Laboratory, Pune, 411008, India
| | - Sourav Pal
- Department of Chemistry, Indian Institute of Technology, Powai, Mumbai, 400076, India. .,Department of Chemical Science, Indian Institute of Science Education and Research, Kolkata, Mohanpur, Nadia, West Bengal, 741246, India.
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Sengupta T, Khan MS, Pal S. Mechanistic Investigation of the Carbon-Iodine Bond Activation on the Niobium-Carbon Cluster. ACS Omega 2017; 2:5335-5347. [PMID: 31457802 PMCID: PMC6644337 DOI: 10.1021/acsomega.7b00894] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2017] [Accepted: 08/18/2017] [Indexed: 05/10/2023]
Abstract
The activation process of carbon-iodine (C-I) bond on neutral and cationic niobium metcars (Nb8C12) is investigated using density functional theory and related computational techniques. Metallocarbohedrenes or metcars are a class of stable metal-carbide clusters of specific stoichiometry and of great interest to cluster chemists since their first discovery. The detailed reaction mechanism along with the overall energy profile of the C-I dissociation reaction on niobium metcar and its cations is presented in this paper. The tunneling-corrected rate constants and their related reaction parameters such as the pre-exponential factor are also included alongside. The major differences between the reaction mechanism of the neutral and cationic metcars are also highlighted as well. Despite the available experimental results, the C-I bond dissociation on metcars has remained an unexplored problem in the theoretical and computational domains. Thus, the present investigation can fill in the gap and may also provide new insights provoking further developments in cluster and materials chemistry in future.
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Affiliation(s)
- Turbasu Sengupta
- Physical
Chemistry Division, CSIR National Chemical
Laboratory, Pune 411008, India
| | - Muntazir S. Khan
- Physical
Chemistry Division, CSIR National Chemical
Laboratory, Pune 411008, India
| | - Sourav Pal
- Department
of Chemistry, Indian Institute of Technology
Bombay, Powai, Mumbai 400076, India
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Abstract
The stability and electronic structure of radical attached aluminum nanoclusters are investigated using density functional theory (DFT). A detailed investigation shows good correlation between the thermodynamic stability of radical attached clusters and the stability of the attached radical anions. All other calculated parameters like HOMO-LUMO gap and charge transfer are also found to be consistent with the observed thermodynamic stabilities of the complexes. Investigation of the electronic structure of radical attached complexes further shows the presence of jellium structures within the core similar to the ligated clusters. Comparison with available experimental and theoretical data also proves the validity of superatomic complex theory for the radical attached clusters as well. Based on the evaluated thermodynamic parameters, selected radical attached clusters are observed to be more thermodynamically stable in comparison with experimentally synthesized ligated clusters. Stabilization of small metal clusters is one of the greatest challenges in current cluster science and the present investigation confirms the fact that radical attached clusters can provide a viable alternative to ligated clusters in the future.
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Affiliation(s)
- Turbasu Sengupta
- Physical Chemistry Division, CSIR National Chemical Laboratory, Pune 411008, India.
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Abstract
A cost-effective equation of motion coupled cluster method, EOMIP-CCSD(2), is used to investigate vertical and adiabatic ionization potential as well as ionization-induced structural changes of water clusters and compared with CCSD(T), CASPT2, and MP2 methods. The moderate N(5) scaling and low storage requirement yields EOMIP-CCSD(2) calculation feasible even for reasonably large molecules and clusters with accuracy comparable to CCSD(T) method at much cheaper computational cost. Our calculations shed light on the authenticity of EOMIP-CCSD(2) results and establish a reliable method to study of ionization energy of molecular clusters. We have further investigated the performance of several classes of DFT functionals for ionization energies of water clusters to benchmark the results and to get a reliable functionals for the same.
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Affiliation(s)
- Susanta Das
- Physical Chemistry Division, CSIR-National Chemical Laboratory , Pune 411008, India
| | - Turbasu Sengupta
- Physical Chemistry Division, CSIR-National Chemical Laboratory , Pune 411008, India
| | - Achintya Kumar Dutta
- Physical Chemistry Division, CSIR-National Chemical Laboratory , Pune 411008, India
| | - Sourav Pal
- Department of Chemistry, Indian institute of Technology Bombay , Powai, Mumbai 400 076, India
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Abstract
Plant-derived natural products have made their own niche in the treatment of neurological diseases since time immemorial. Parkinson's disease (PD), the second most prevalent neurodegenerative disorder, has no cure and the treatment available currently is symptomatic. This chapter thoughtfully and objectively assesses the scientific basis that supports the increasing use of these plant-derived natural products for the treatment of this chronic and progressive disorder. Proper considerations are made on the chemical nature, sources, preclinical tests and their validity, and mechanisms of behavioural or biochemical recovery observed following treatment with various plants derived natural products relevant to PD therapy. The scientific basis underlying the neuroprotective effect of 6 Ayurvedic herbs/formulations, 12 Chinese medicinal herbs/formulations, 33 other plants, and 5 plant-derived molecules have been judiciously examined emphasizing behavioral, cellular, or biochemical aspects of neuroprotection observed in the cellular or animal models of the disease. The molecular mechanisms triggered by these natural products to promote cell survivability and to reduce the risk of cellular degeneration have also been brought to light in this study. The study helped to reveal certain limitations in the scenario: lack of preclinical studies in all cases barring two; heavy dependence on in vitro test systems; singular animal or cellular model to establish any therapeutic potential of drugs. This strongly warrants further studies so as to reproduce and confirm these reported effects. However, the current literature offers scientific credence to traditionally used plant-derived natural products for the treatment of PD.
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Affiliation(s)
- T Sengupta
- Division of Cell Biology & Physiology, Indian Institute of Chemical Biology (CSIR, Govt of India), 4, Raja S.C. Mullick Road, Jadavpur, Kolkata, 700 032, India
| | - J Vinayagam
- Division of Chemistry, Indian Institute of Chemical Biology (CSIR, Govt of India), 4, Raja S.C. Mullick Road, Kolkata, 700 032, India
| | - R Singh
- Division of Cell Biology & Physiology, Indian Institute of Chemical Biology (CSIR, Govt of India), 4, Raja S.C. Mullick Road, Jadavpur, Kolkata, 700 032, India
| | - P Jaisankar
- Division of Chemistry, Indian Institute of Chemical Biology (CSIR, Govt of India), 4, Raja S.C. Mullick Road, Kolkata, 700 032, India
| | - K P Mohanakumar
- Division of Cell Biology & Physiology, Indian Institute of Chemical Biology (CSIR, Govt of India), 4, Raja S.C. Mullick Road, Jadavpur, Kolkata, 700 032, India. .,Inter University Centre for Biomedical Research & Super Specialty Hospital, Mahatma Gandhi University Campus at Thalappady, Rubber Board PO, Kottayam, 686009, Kerala, India.
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Sengupta T, Bhushan M, Wangikar PP. A Computational Approach Using Ratio Statistics for Identifying Housekeeping Genes from cDNA Microarray Data. IEEE/ACM Trans Comput Biol Bioinform 2015; 12:1457-1463. [PMID: 26671815 DOI: 10.1109/tcbb.2015.2407399] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
We predict housekeeping genes from replicate microarray gene expression data of human lymphoblastoid cells and liver tissue with outliers removed using a scoring scheme, by an algorithm based on statistical hypothesis testing, assuming that such genes are constitutively expressed. A few predicted genes were examined and found to be housekeeping.
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Abstract
Energetics and the in-depth reaction mechanism of the oxidative addition step of the cross-coupling reaction are studied in the framework of density functional theory (DFT) on aluminum nanoclusters. Aluminum metal in its bulk state is totally inactive towards carbon-halogen bond dissociation but selected Al nanoclusters (size ranging from 3 to 20 atoms) have shown a significantly lower activation barrier towards the oxidative addition reaction. The calculated energy barriers are lower than the gold clusters and within a comparable range with the conventional and most versatile Pd catalyst. Further investigations reveal that the activation energies and other reaction parameters are highly sensitive to the geometrical shapes and electronic structures of the clusters rather than their size, imposing the fact that comprehensive studies on aluminum clusters can be beneficial for nanoscience and nanotechnology. To understand the possible reaction mechanism in detail, the reaction pathway is investigated with the ab initio Born Oppenheimer Molecular Dynamics (BOMD) simulation and the Natural Bond Orbital (NBO) analysis. In short, our theoretical study highlights the thermodynamic and kinetic details of C-I bond dissociation on aluminum clusters for future endeavors in cluster chemistry.
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Affiliation(s)
- Turbasu Sengupta
- Physical Chemistry Division, CSIR-National Chemical Laboratory, Pune 411008, India.
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Abstract
Background: Drug utilization studies provide a pharmacoeconomic basis for making evidence-based health-care decisions. In ophthalmology practice, rational prescribing plays a crucial role in reducing the ocular disease burden. Aim: The aim of the study was to investigate the drug utilization pattern in ophthalmology out-patient department (OPD) of a Medical College in India. Subjects and Methods: A prospective, cross-sectional study was conducted for a period of 2 months. The prescriptions for all consecutive patients attending the OPD for the first time (first time encounter) were included and audited using a pre-designed form to record information from the OPD prescription cards of each patient. Data analysis was carried out using the descriptive statistical methods: Frequencies, percentage, mean and standard deviation. Results: A total of 640 prescriptions were analyzed with the average number of drugs per prescription being 2.4 (0.9). The most common disorders diagnosed were refractive errors (31.6% [202/640]) followed by cataract, glaucoma and others. Drugs were prescribed in different dosage forms with eye drops being the most common (70.8% [1073/1516]) followed by tablets (15.9% [241/1516]), ointment (6.1% [93/1516]), syrup (1.1% [16/1516]) and others; injections contributed 2.1% (30/1516) of all dosage forms. The frequency of drug administration and duration of treatment was recorded in 96% (614/640) and 75% (480/640) of all prescriptions respectively. Antimicrobials were most commonly prescribed (36.4% [552/1516]) followed by anti-inflammatory and anti-allergic (24.2% [367/1516]), anti-glaucoma medications (21.4% [323/1516]), mydriatic and cycloplegics (7.2% [109/1516]), miotics (6.2% [94/1516]), multivitamins (4.6% [70/1516]). Drugs were predominantly prescribed in brand name 83% (1258/1516) instead of generic name. A total of 62% (940/1516) of drugs were prescribed from national essential medicine list. Conclusion: The present study revealed certain lacunae in the prescribing practices of the Ophthalmologists of the institute as evidenced by low generic prescribing, inadequate information about frequency of administration and duration of therapy in many prescriptions. This can be addressed through proper sensitization of clinicians in the art of rational prescribing.
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Affiliation(s)
- I Banerjee
- Department of Clinical and Experimental Pharmacology, School of Tropical Medicine, Kolkata, West Bengal, India
| | - T Bhadury
- Department of Medicine, AMRI Hospitals Limited, Kolkata, West Bengal, India
| | - T Sengupta
- Department of Pharmacology, NRS Medical College, Kolkata, West Bengal, India
| | - D Roy
- Department of Opthalmology, Burdwan Medical College and Hospital, Burdwan, West Bengal, India
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Sengupta T, Mohanakumar K. 2-Phenylethylamine, a constituent of chocolate and wine, causes mitochondrial complex-I inhibition, generation of hydroxyl radicals and depletion of striatal biogenic amines leading to psycho-motor dysfunctions in Balb/c mice. Neurochem Int 2010; 57:637-46. [DOI: 10.1016/j.neuint.2010.07.013] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2010] [Revised: 06/29/2010] [Accepted: 07/24/2010] [Indexed: 01/08/2023]
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Mukhopadhyay A, Hazra PP, Sengupta T, Saha R, Nandi R, Sengupta S. Protein-protein interaction conferring stability to an extracellular acetyl (xylan) esterase produced by Termitomyces clypeatus. Biotechnol Prog 2003; 19:720-6. [PMID: 12790630 DOI: 10.1021/bp0201307] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Acetyl esterase (AE) activity present in the culture filtrate of Termitomyces clypeatus was separated into lower molar mass (LMM) and higher molar mass (HMM) protein fractions during BioGel P-200 gel chromatography. AE was purified as a 30 kDa nonglycosylated protein from LMM fractions by CM-Sepharose ion exchange chromatography and HPGPLC. Although the HMM fraction had a number of enzyme activities (sucrase, beta-xylosidase, beta-glucosidase, and alpha-L-arabinofuranosidase) other than AE, protein present in the fraction was eluted as a single protein peak in HPGPLC and gave a single band in native PAGE. The fraction, subsequently purified by DEAE-Sephadex chromatography, was a SDS-PAGE homogeneous 80 kDa glycoprotein, but with both AE and cellobiase activities. The aggregate dissociated during ConA-Sepharose chromatography and 30 kDa AE and 56 kDa glycosylated cellobiase were purified separately. The dissociation caused significant loss of cellobiase activity but not that of AE. AE purified from both HMM and LMM fractions was characterized to be the same enzyme in terms of molar masses, pI (7.3), and other physicochemical properties. AE as an aggregate with cellobiase showed higher thermostability, temperature optimum, and resistance toward chemical denaturants than those of purified AE. Compared to cellobiase purified earlier from the same fungus, the enzyme present with AE in the aggregate also showed higher catalytic activity, thermostability, and temperature optimum. The study indicated that the formation of such SDS-resistant enzyme aggregate was associated with significant changes in the physicochemical properties of the enzymes, mainly toward improvement of rigidity of enzymes, and sometimes with the improvement of catalytic activity.
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Affiliation(s)
- A Mukhopadhyay
- Department of Applied Biochemistry, Indian Institute of Chemical Biology, 4 Raja SC Mullick Road, Kolkata 700032, India
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Abstract
Lateral phase separation in two-dimensional mixed films of soy 11S/beta-casein, acidic subunits of soy 11 (AS11S)/beta-casein, and alpha-lactalbumin/beta-casein adsorbed at the air-water interface has been studied using an epifluorescence microscopy method. No distinct lateral phase separation was observed in the mixed protein films when they were examined after 24 h of adsorption from the bulk phase. However, when the soy 11S/beta-casein and AS11S/beta-casein films were aged at the air-water interface for 96 h, phase-separated regions of the constituent proteins were evident, indicating that the phase separation process was kinetically limited by a viscosity barrier against lateral diffusion. In these films, beta-casein always formed the continuous phase and the other globular protein the dispersed phase. The morphology of the dispersed patches was affected by the protein composition in the film. In contrast with soy 11S/beta-casein and AS11S/beta-casein films, no lateral phase separation was observed in the alpha-lactalbumin/beta-casein film at both low and high concentration ratios in the film. The results of these studies proved that proteins in adsorbed binary films exhibit limited miscibility, and the deviation of competitive adsorption behavior of proteins at the air-water interface from that predicted by the ideal Langmuir model (Razumovsky, L.; Damodaran, S. J. Agric. Food Chem. 2001, 49, 3080-3086) is in fact due to thermodynamic incompatibility of mixing of the proteins in the binary film. It is hypothesized that phase separation in adsorbed mixed protein films at the air-water and possibly oil-water interfaces of foams and emulsions might be a source of instability in these dispersed systems.
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Affiliation(s)
- T Sengupta
- Department of Food Science, University of Wisconsin-Madison, Madison, WI 53706, USA
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Das A, Dasgupta A, Sharma S, Ghosh M, Sengupta T, Bandopadhyay S, Majumder HK. Characterisation of the gene encoding type II DNA topoisomerase from Leishmania donovani: a key molecular target in antileishmanial therapy. Nucleic Acids Res 2001; 29:1844-51. [PMID: 11328867 PMCID: PMC37264 DOI: 10.1093/nar/29.9.1844] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The gene encoding type II DNA topoisomerase from the kinetoplastid hemoflagellated protozoan parasite Leishmania donovani (LdTOP2) was isolated from a genomic DNA library of this parasite. DNA sequence analysis revealed an ORF of 3711 bp encoding a putative protein of 1236 amino acids with no introns. The deduced amino acid sequence of LdTOP2 showed strong homologies to TOP2 sequences from other kinetoplastids, namely Crithidia and Trypanosoma spp. with estimated identities of 86 and 68%, respectively. LdTOP2 shares a much lower identity of 32% with its human homologue. LdTOP2 is located as a single copy on a chromosome in the 0.7 Mb region in the L.donovani genome and is expressed as a 5 kb transcript. 5'-Mapping studies indicate that the LdTOP2 gene transcript is matured post-transcriptionally with the trans-splicing of the mini-exon occurring at -639 from the predicted initiation site. Antiserum raised in rabbit against glutathione S-transferase fusion protein containing the major catalytic portion of the recombinant L.donovani topoisomerase II protein could detect a band on western blots at approximately 132 kDa, the expected size of the entire protein. Use of the same antiserum for immunolocalisation analysis led to the identification of nuclear, as well as kinetoplast, antigens for L.donovani topoisomerase II. The in vitro biochemical properties of the full-length recombinant LdTOP2 when overexpressed in E.coli were similar to the Mg(II) and ATP-dependent activity found in cell extracts of L.donovani.
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Affiliation(s)
- A Das
- Molecular Parasitology Laboratory, Indian Institute of Chemical Biology, 4 Raja S.C. Mullick Road, Calcutta 700032, India
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Sengupta T, Basu S. Magnetic field effect on the exciplex between all-s-trans- 1,4-diphenylbuta- 1,3-diene and 1,4-dicyanobenzene: a comparative study with other alpha,omega-diphenyl polyenes. Spectrochim Acta A Mol Biomol Spectrosc 2001; 57A:1103-1110. [PMID: 11374570 DOI: 10.1016/s1386-1425(00)00429-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The exciplex between all-s-trans-1,4-diphenylbuta-1,3-diene and 1,4-dicyanobenzene has been studied by steady state fluorescence along with the magnetic field effect (MFE) and compared with the other alpha,omega-diphenyl polyenes. The exciplex formation and magnetic field effect are dictated by the chain length of the polyene rather than the electronic requirement of these phenomena. The wavelength dependence of the MFE confirms the presence of two different charge-transfer complexes.
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Affiliation(s)
- T Sengupta
- Chemical Sciences Division, Saha Institute of Nuclear Physics, Calcutta, India
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Sengupta T, Damodaran S. Incompatibility and Phase Separation in a Bovine Serum Albumin/beta-Casein/Water Ternary Film at the Air-Water Interface. J Colloid Interface Sci 2000; 229:21-28. [PMID: 10942539 DOI: 10.1006/jcis.2000.6992] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Thermodynamic incompatibility and two-dimensional phase separation in a bovine serum albumin (BSA)/beta-casein/water ternary film at the air-water interface has been studied using an epifluorescence microscopy technique. The incompatibility between BSA and beta-casein at the air-water interface was deduced from deviation of the experimental equilibrium composition of the proteins in the mixed saturated monolayer film from that predicted by the Langmuir-type competitive adsorption model at various bulk concentration ratios. Fluorescence microscopy of the mixed monolayer film showed distinct phase-separated BSA-rich and beta-casein-rich regions coexisting with inhomogeneous mixed regions. BSA always tended to be the dispersed phase and beta-casein the continuous phase. It is suggested that because the free energy at the "interfaces" between the phase-separated regions is generally higher than at other regions of the film, they may act as zones of instability in protein-stabilized foams and possibly emulsions. Copyright 2000 Academic Press.
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Affiliation(s)
- T Sengupta
- Department of Food Science, University of Wisconsin-Madison, Madison, Wisconsin, 53706
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Abstract
A new methodology has been developed for studying the adsorption behavior of proteins at oil-water interfaces. This technique employs the radiotracer method for monitoring adsorption of 14C-labeled proteins at the oil-water interface. The uniqueness of the new method lies in the formation of a 1000 Å thick triglyceride oil film on the water surface. beta-casein was used to generate a standard curve for relating interfacial radioactivity (µCi/m2) to cpm at the oil-water interface. Adsorption isotherm of beta-casein was determined in the bulk protein concentration range 1.5 x 10(-5)-3.8 x 10(-3)% by weight of solution. The saturated monolayer coverage was found to be about 7.3 mg/m2. This value was quite different from other values reported in the literature. Adsorption studies with another protein, lysozyme, at the oil-water interface also revealed a high surface concentration of 3.0 mg/m2. The most significant difference between the adsorption of beta-casein at the oil-water and air-water interfaces was the lack of an induction period for the development of interfacial pressure in the former. This difference may be attributed to the attractive dispersion interaction between protein molecules and the oil phase. Copyright 1998 Academic Press.
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Affiliation(s)
- T Sengupta
- Department of Food Science, University of Wisconsin-Madison, 1605 Linden Drive, Madison, Wisconsin, 53706
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Sengupta T, Pal TK. Further Observations on the Family Rhizophagidae with Descriptions of Seven New Genera. (Coleoptera, Rhizophagidae). ZOOSYST EVOL 1995. [DOI: 10.1002/mmnz.4830710114] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
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Banerjee AK, Bandyopadhyay S, Gayen AK, Sengupta T, Das AK, Chatterjee GK, Chaudhuri SK. Synthesis and anthelmintic activity of 3-substituted 5-methylthio-isoxazoles. Arzneimittelforschung 1994; 44:863-6. [PMID: 7945524] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Isoxazole derivatives have been shown to possess antiparasitic activity. In the present study, 3-substituted 5-methylthio-isoxazoles were synthesized and tested for anthelmintic activity, along with some other isoxazoles which have been reported but not tested earlier. Nine compounds (2a, 2b, 2e, 2g, 2u, 3a, 3b, 3e and 3f) showed activity against both A. ceylanicum and N. dubius in vitro. Twelve compounds (2a, 2b, 2d, 2e, 2f, 2h, 2l, 2n, 2o, 2u, 3d and 3e) showed activity against N. dubius in vivo, a parasite of veterinary importance.
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Maulik G, Ghosh N, Sengupta T, Chattopadhyay D, Chakraborty AK, Chatterjee GC. Curative effect of methionine on certain enzymes of chick kidney cortex under lanthanum toxicity situation. Indian J Exp Biol 1992; 30:1166-9. [PMID: 1294480] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Acute single dose administration of lanthanum chloride (250 mg/kg body wt, ip) to chicks have been found to alter the levels of enzymes of the antioxidant defence system of chick renal cortex fractions. Such changes involved significant decrease in activities of glucose-6-phosphate dehydrogenase, glutathione reductase, glutathione peroxidase and catalase of kidney epithelial cells. However glutathione-S-transferase activity was not altered. Glutathione and total thiol contents were decreased while lipoperoxidative reactions in kidney-cortex was significantly enhanced. The data indicate that amelioration of lanthanum toxicity condition by methionine supplementation may be due to the methionine serving as a precursor of glutathione.
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Affiliation(s)
- G Maulik
- Department of Biochemistry, University College of Science, Calcutta, India
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Sengupta T, Chattopadhyay D, Ghosh N, Maulik G, Chatterjee GC. Impact of chromium on lipoperoxidative processes and subsequent operation of the glutathione cycle in rat renal system. Indian J Biochem Biophys 1992; 29:287-90. [PMID: 1512015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Oral administration of K2Cr2O7 to male albino rats at an acute dose of 1500 mg/kg body wt/day for 3 days brought about sharp decrease in the activities of glucose-6-phosphate dehydrogenase and glutathione reductase of kidney epithelial cells. The scavenging system of kidney epithelium is also affected as evident by the highly significant fall in the activities of glutathione peroxidase, superoxide dismutase and catalase which ultimately leads to the increase in lipid peroxidation value in kidney cortical homogenate. However, glutathione-s-transferase activity in cytosol and glutathione and total thiol content in cortical homogenate were not altered. Chronic oral administration of K2Cr2O7 (300 mg/kg body wt/day) for 30 days to rats lead to elevation in the activities of glutathione peroxidase, glutathione reductase, glutathione-s-transferase, superoxide dismutase and catalase with no change in glucose-6-phosphate dehydrogenase activity in epithelial cells. This might lead to the increase in glutathione and total thiol status and decrease in lipid peroxidation value in whole homogenate system.
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Affiliation(s)
- T Sengupta
- Department of Biochemistry, University College of Science, Calcutta
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Sengupta T, Ghosh S, Haldar D. The Biology of Eliptocystis triboli n. gen., n. sp., infecting the larvae of Tribolium castaneum (Herbst) in Walnuts. ACTA ACUST UNITED AC 1991. [DOI: 10.1016/s0003-9365(11)80190-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/15/2022]
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Sengupta T, Chattopadhyay D, Ghosh N, Das M, Chatterjee GC. Effect of chromium administration on glutathione cycle of rat intestinal epithelial cells. Indian J Exp Biol 1990; 28:1132-5. [PMID: 2099328] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Acute oral administration of K2Cr2O7 (1500 mg/kg body wt/day) for 3 days to rats led to the decrease in activities of glucose-6-phosphate dehydrogenase, glutathione peroxidase, glutathione reductase, glutathione-S-transferase, superoxide dismutase and catalase of intestinal epithelial cells. Glutathione and total thiol contents were decreased while lipid peroxidation was increased markedly using the whole homogenate of the intestinal epithelial cells. Chronic oral administration of K2Cr2O7 (300 mg/kg body wt/day) for 30 days to rats on the other hand, led to marked increase in superoxide dismutase and glutathione peroxidase activities with no appreciable change in glucose-6-phosphate dehydrogenase, glutathione reductase and catalase activities. However, glutathione-S-transferase activity was decreased significantly. In the whole homogenate of rat intestine, glutathione and total thiol contents were decreased not so significantly but there was a slight enhancement in lipid peroxidation value.
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Affiliation(s)
- T Sengupta
- Department of Biochemistry, University College of Science, Calcutta, India
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Dasgupta J, Datta C, Sengupta T, De S, Sengupta D. Age-related changes of glycogen metabolism in human fetal heart. Indian J Biochem Biophys 1989; 26:123-5. [PMID: 2777320] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The changes in the activities of three important glycogen metabolising enzymes, viz. glycogen synthetase, glycogen phosphorylase and alpha-D-glucosidase, along with glycogen content have been measured in adult human heart and human fetal heart collected at 13-36 weeks of gestation. At an early period, particularly 13-16 weeks of gestational age, the activity of glycogen synthetase and glycogen content were found to be maximum. However the activity of glycogen phosphorylase remained constant throughout the gestation and that of alpha-D-glucosidase showed a peak at 25-28 weeks of gestation, thereby indicating that fetal heart tissue has the capacity to utilise glycogen for energy.
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Saha UK, Sengupta T, Sirkar A, Sengupta D. Biochemical studies on the in vitro effect of doxepin on Mg2+ & Na+, K+)-ATPases of human foetal & adult brain. Indian J Med Res 1989; 90:27-31. [PMID: 2542157] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
The in vitro effect of doxepin at 10, 50 and 200 micrograms/mg protein on Mg2+ and (Na+ K+)-ATPases (EC 3.6.1.3) activities of human foetal and adult brain (crude homogenate of cerebrum and cerebellum) were studied at 10-30 wk of gestation. Both Mg2+ and (Na+, K+)-ATPases of human foetal and adult brain were found to be inhibited by doxepin in a dose dependent manner. The inhibitory effect neither varied with respect to the region (i.e., cerebrum and cerebellum) nor with the gestational ages. Inhibition of ATPases activity by doxepin may affect the release and uptake of biogenic amines in the CNS, which may hamper the maturation of brain.
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Saha UK, Sengupta T, Dutta C, Sirkar A, Sengupta D. In vitro effect of lorazepam on Mg2+ and (Na+,K+) ATPases of human foetal brain. Indian J Exp Biol 1989; 27:44-6. [PMID: 2558074] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Lorazepam (LZ), a benzodiazepine group of drug, inhibits Mg2+ and (Na+,K+) ATPases (EC 3.6.1.3) activity of human foetal and adult brain. The inhibitory effect neither varied with respect to the region (i.e. cerebrum and cerebellum) nor with the age of the foetus. The inhibition of ATPases activity indicates that the neuronal transmission processes, may be affected and raises the possibility of developmental disturbances.
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Sengupta T, Dutta C, Dasgupta J, Sengupta D. Developmental changes of TCA cycle enzymes in human fetal brain. Indian J Biochem Biophys 1988; 25:404-7. [PMID: 3243557] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
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Datta KM, Dasgupta J, Sengupta T, De S, Sengupta. Erratum to: Glycogen metabolism in human fetal testes. J Biosci 1988. [DOI: 10.1007/bf02712160] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Datta C, Sengupta T, Dasgupta J, Saha U, De K, Sengupta D. Testicular enzymes as a marker of development in human fetus. Int J Fertil 1987; 32:380-3. [PMID: 2889685] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The activities of different testicular enzymes, as a marker of development, have been determined at various gestational ages. The enzyme sorbitol dehydrogenase shows peak activity between 25 and 28 weeks of gestation, whereas the peak of hyaluronidase was observed between 14 and 16 weeks of gestation. The activities of pentose phosphate enzymes, such as glucose-6-phosphate dehydrogenase and transketolase in developing human fetus reach the highest level between 25 and 28 weeks and 21 and 24 weeks of gestation, respectively, indicating the most actively synthesizing period of the fetus for providing NADPH and ribose-5-phosphate for steroidogenesis and nucleotide and nucleic acid synthesis.
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Affiliation(s)
- C Datta
- Department of Biochemistry, University College of Science, University of Calcutta, India
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Sengupta T, Dasgupta J, Datta C, Sengupta D. Developmental pattern of enzymes related to glycolysis in human foetal brain. Indian J Med Res 1987; 86:397-400. [PMID: 2962937] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
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Sengupta T, Datta C, Dasgupta J, De K, Saha U, Sengupta D. In vitro effect of aspirin on NADPH producing pathway in developing human fetus. Indian J Exp Biol 1987; 25:202-3. [PMID: 3666819] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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Sengupta T, Datta C, Dasgupta J, Sengupta D. Age related changes of gluconeogenic activity in human placenta during foetal development. Indian J Med Res 1986; 84:385-9. [PMID: 3781594] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
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