Publications by authors named "Asoke P Chattopadhyay"

Herein we have made a comparative study of the efficiency of three different nanotubes viz. Carbon nanotube (CNT), boron nitride nanotube (BNNT) and silicon carbide nanotube (SiCNT) to deliver the cancerous drug, Azacitidine (AZD). The atomistic description of the encapsulation process of AZD in these nanotubes has been analyzed by evaluating parameters like adsorption energy, electrostatic potential map, reduced density gradient (RDG).

View Article and Find Full Text PDF

Arsenic (As) is a highly poisonous heavy metal with major environmental ramifications. Inorganic components such as zinc (Zn) and iron (Fe), as well as organic vermicompost, have been used as management solutions, with limited attempts of using them together. The current study involved preparing non-enriched vermicompost as well as six distinct Zn and Fe enriched vermicomposts and analyzing their chemical composition using the standard procedures.

View Article and Find Full Text PDF

A pH-regulated hydrothermal synthesis method was employed to synthesize SbOBr and SbOCl crystallites. Characterization is done by single crystal X-ray diffraction, powder X-ray diffraction, infra-red spectroscopy, scanning electron microscopy and DFT studies. The compounds crystallize in monoclinic symmetry with a 2/ space group.

View Article and Find Full Text PDF

Using molecular docking and other studies, 20 compounds extracted from (L.) Solms were screened, and their inhibitory efficiency examined against main protease (3CLpro) of SARS CoV-2. All the compounds were found to binding with 3CLpro through van der Waals and electrostatic forces of attractions.

View Article and Find Full Text PDF

A Co(III) complex of 1-amino-4-hydroxy-9,10-anthraquinone (QH) (Scheme-1) having the molecular formula CoQ (Scheme-2) was prepared and characterized by elemental analysis, FTIR spectroscopy, UV-vis spectroscopy, fluorescence spectroscopy, and mass spectrometry. In the absence of a single crystal, the energy-optimized molecular structure of CoQ was determined by employing computational methods that was validated using spectroscopic evidences, elemental analysis, and mass spectrometry data. The electrochemical properties of the complex were analyzed using cyclic voltammetry and indicate a substantial modification of the electrochemical properties of the parent amino-hydroxy-9,10-anthraquinone.

View Article and Find Full Text PDF

Introduction: The current therapeutic armory for visceral leishmaniasis (VL) caused by complex is inadequate, coupled with serious limitations. Combination therapy has proved ineffective due to mounting resistance; however, the search for safe and effective drugs is desirable, in the absence of any vaccine. There is a growing interest in the application of nanoparticles for the therapeutic effectiveness of leishmaniasis.

View Article and Find Full Text PDF

Herein we have investigated the ability of the (6,6) MoS-nanotube (NT) to sense environmentally hazardous electrophilic and nucleophilic gases using density functional theory (DFT). CO, CO, HO and NH gases were chosen for adsorption on the (6,6) MoS-NT and different adsorption parameters such as adsorption energy, projected density of states (PDOS), band structure and structural changes after adsorption were evaluated. Nucleophilic gases NH and HO showed a fairly high amount of electron density transfer from gas molecules to the NT while the opposite trend was realized for electrophilic gases CO and CO.

View Article and Find Full Text PDF

The main binding site for SARS-COV-2 spike protein in human body is human Angiotensin converting enzyme 2 (ACE2) protein receptor. Herein we present the effect of chloroquine (CLQ) on human ACE2 receptor. Molecular docking studies showed that chloroquine have a docking score is quite high compare to other well known drugs.

View Article and Find Full Text PDF

(Neem) extracts have been known for their anti-bacterial and other effects since ancient times. The present work examines the inhibitory activity of Neem extracts on Papain like protease (PLpro) of the novel coronavirus SARS-CoV-2. The activity is analysed by molecular docking study along with molecular dynamics simulation.

View Article and Find Full Text PDF

The present work is an investigation to test hydroxychloroquine as an inhibitor for the COVID-19 main protease. Molecular docking studies revealed a high docking score and interaction energies and decent level of docking within the cavity in protease moiety. Molecular dynamics simulations also lead to the evaluation of conformational energies, average H-bonding distance, RMSD plots etc.

View Article and Find Full Text PDF

Polyvinyl-pyrrolidone capped spherical cadmium sulphide quantum dots (CdS-PVP QDs), 2-6 nm in size, were developed as a selective turn-on fluorescence nanosensor for monohydrogen phosphate ion (HPO) in aqueous medium. Fluorescence intensity of CdS-PVP QDs significantly increased with addition of HPO ions, whereas the other common inorganic ions had very little effect on the fluorescence intensity. The proposed sensor may be efficiently used for the detection of HPO ions at a low level of concentration up to 213 nM in real urine sample.

View Article and Find Full Text PDF

Pollution of aquatic resources is increasing day-by-day, and phenolic compounds are common pollutants negatively impacting aquatic biodiversity and production. This study aimed at isolation of phenol hyper-tolerant bacteria from polluted aquaculture resource so that they might be useful in aquaculture systems. Four phenol hyper-tolerant bacterial strains were isolated from sewage fed East Kolkata Wetlands, a Ramsar site.

View Article and Find Full Text PDF

A well designed, new pyrene based small molecule (L) was synthesized from 1:1 condensation reaction of 1-aminopyrene and 6-(1,3-benzodioxal-5-yl)-2-pyridine carboxaldehyde which was characterized by absorption, emission spectrometry, FTIR, NMR and mass studies. Interestingly the UV-vis and fluorescence spectroscopic studies revealed that the ligand (L) works as a dual turn-on luminescent chemosensor for chromium(III) (Cr) and aluminium(III) (Al) in aqueous environment which were further supported by DFT and TDDFT studies. L shows a significant colour change from pale yellow to reddish yellow with a detection limit of ~10 M in the presence of Cr and Al whereas there were no noteworthy changes in the presence of other monovalent and divalent metal ions.

View Article and Find Full Text PDF

Three new tetranuclear iron(III) and zinc(II) complexes, [Fe(cpdp)(phth)(OH)]·8HO (1), [Fe(cpdp)(terephth)(OH)] (2), and [Zn(Hcpdp)(suc)]Br·12HO (3), have been synthesized as models for the active site of phosphoester hydrolases by utilizing a polydentate ligand, N, N'-bis[2-carboxybenzomethyl]- N, N'-bis[2-pyridylmethyl]-1,3-diaminopropan-2-ol (Hcpdp) in combination with exogeneous phthalate (phth), terephthalate (terephth), and succinate (suc). Single crystal X-ray analyses reveal that the metallic core of complex 1 consists of four distorted octahedral iron(III) ions with average intraligand Fe---Fe separation of 3.656(2) Å, while the structure 3 represents a tetranuclear metallic core containing four distorted trigonal bipyramidal zinc(II) ions with average intraligand Zn---Zn separation of 3.

View Article and Find Full Text PDF

We investigated the reactivity of carbon monoxide on tetrahedral Ni clusters at different spin multiplicity applying density functional theory calculations considering pure and hybrid functional. The stability of the clusters increases with the increasing spin multiplicity and doping hydrogen in Ni cluster. The adsorption or binding energy of CO on Ni cluster is thermodynamically feasible process at normal condition whereas dissociation is not feasible.

View Article and Find Full Text PDF

Visceral leishmaniasis (VL) is a fatal, vector-borne disease caused by the intracellular protozoa of the genus . Most of the therapeutics for VL are toxic, expensive, or ineffective. Sesquiterpenes are a new class of drugs with proven antimicrobial and antiviral activities.

View Article and Find Full Text PDF

An Fe3O4-graphene oxide nanocomposite has been synthesized via a chemical reaction with a magnetite particle size of 18-25 nm. The resulting nanocomposite can be easily manipulated by an external magnetic field, exhibits excellent catalytic activity and may be reused for several cycles with marginal loss of activity. This recyclable nanocomposite provides an efficient, economic, novel route for multi-component A(3) coupling reactions of aldehydes, amines and alkynes and gives the propargylamine in excellent yields.

View Article and Find Full Text PDF

Visceral leishmaniasis (VL) is a fatal vector-borne parasitic syndrome attributable to the protozoa of the Leishmania donovani complex. The available chemotherapeutic options are not ideal due to their potential toxicity, high cost and prolonged treatment schedule. In the present study, we conjectured the use of nano drug delivery systems for plant-derived secondary metabolite; artemisinin as an alternative strategy for the treatment of experimental VL.

View Article and Find Full Text PDF

Background: Gradual attainment of bacterial resistance to antibiotics led us to develop a robust method of synthesis of stable, colloidal cupric oxide nanoparticle of physiological pH with potential antibacterial action.

Methods: Cu(II) oxide NP was synthesized by reduction-oxidation of CuCl2, using polyvinyl alcohol as stabilizer. Characteristics and antibacterial activity of the particles were investigated by techniques like UV-Vis spectrophotometry, DLS, AFM, TEM, EDS, FTIR, AAS, agar plating, FACS, gel electrophoresis and XPS.

View Article and Find Full Text PDF

A highly selective femtomolar level sensing of inorganic arsenic(III) as arsenious acid has been accomplished in water medium and in living-systems (on pollen grains of Tecoma stans; Candida albicans cells (IMTECH No. 3018) and Peperomia pellucida stem section) using a non-toxic fluorescent probe of a Cu(II)-complex.

View Article and Find Full Text PDF

Hypothesis: Artemisinin, a potential antileishmanial compound with poor bioavailability and stability has limited efficacy in visceral leishmaniasis. Encapsulating artemisinin into poly lactic-co glycolic nanoparticles may improve its effectiveness and reduce toxicity.

Experiments: Artemisinin-loaded nanoparticles were prepared, optimized (using Box-Behnken design) and characterized by dynamic light scattering technique, Atomic force microscopy (AFM), Transmission electron microscopy (TEM) and Fourier Transform-Infra Red spectroscopy.

View Article and Find Full Text PDF

O-tert-Butyldiphenylsilyl coumarin 1 and 2 dicoumarol have been synthesized and their anion binding properties have been examined in organic and aqueous organic solvents. Compound 1 senses F(-) selectively over the other anions examined in CHCl3 by exhibiting a greater increase in emission. In contrast, compound 2 shows similar selectivity in CHCl3 giving ratiometric change in emission as well as color.

View Article and Find Full Text PDF

A method for preparation of copper nanoparticles (Cu-NPs) was developed by simple reduction of CuCl2 in the presence of gelatin as a stabilizer and without applying stringent conditions like purging with nitrogen. The NPs were characterized by spectrophotometry, dynamic light scattering, x-ray diffraction, transmission electron microscopy, atomic force microscopy and x-ray photoelectron spectroscopy. The particles were about 50-60 nm in size and highly stable.

View Article and Find Full Text PDF