Browsing by Author "G.K. Gupta"

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Development and performance evaluation of amphotericin B transfersomes against resistant and sensitive clinical isolates of visceral leishmaniasis
(2010) D. Singodia; G.K. Gupta; A. Verma; V. Singh; P. Shukla; P. Misra; S. Sundar; A. Dube; P.R. Mishra
The present study was aimed to assess the efficacy of developed transfersome (TF-3) formulation bearing amphotericin B (AmB) against sensitive and resistant clinical isolates of L donovani and compared with conventional liposomal formulation (F-2) and free AmB (F-1). The skin permeation of AmB from TF-3 was performed using Franz diffusion cell using rat skin which showed fickian diffusion across the skin. When tested against L. donovani (intramacrophagic amastigotes), it has been observed that TF was more effective than F-1 and F-2 formulation in sensitive and resistant clinical isolates. The data provides evidences that the TF formulation owing to its fluidized behaviour imparted by sodium deoxycholate, enables to penetrate well in the infected cells and thus provide enhanced activity. The permeation study also supports this data as the flux value of AmB through TF formulation was 1.5 fold higher compared to conventional liposomes suggesting improved penetration and better partitioning in skin layers. Implicit to this preliminary data it is evident that the AmB loaded TF formulation has potential as alternate chemotherapeutic approach to control of VL. Potential utilities of novel formulation as a transdermal delivery of AmB for leishmaniasis necessitates further elaborated investigations which is underway in our laboratory. Copyright © 2010 American Scientific Publishers All rights reserved.
Fabrication of manganese ferrite-reduced graphene oxide nanostructure as an electrode material for high performance supercapacitor
(Springer Nature, 2024) G.K. Gupta; P. Sagar; Monika Srivastava; A.K. Singh; Sharmistha Anwar; Jai Singh; Ajit Kumar; S.K. Srivastava; Amit Srivastava
Recent studies corroborate spinel transition metal oxides as an apical and paramount electrode materials for supercapacitors as an energy storage device, however, some adventitious stability factors restrict their practical applications. The low specific energy and poor electrical conductivity are assumed as prime factors of concerns for these prospective electrode materials. To address such issues, in the current study, we have employed an integrative strategy to synthesize a three-dimensional hierarchical electrode material consisting of manganese ferrite-reduced graphene oxide (MnFe2O4@rGO) nanostructures by a straightforward hydrothermal procedure and subsequently explored its electrocapacitive performance. X-ray diffraction (XRD), transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDAX), and X-ray photo spectrometer (XPS) have all been used to analyse the physicochemical properties of the materials. Moreover, using a three-electrode system and a 3 M KOH electrolyte solution, the electrocapacitive performances of the as-synthesised samples have been assessed through galvanostatic charge–discharge (GCD), cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS). As-prepared hierarchical electrode material exhibits gravimetric specific capacitance of 399.17 Fg−1 at a current density of 0.65 Ag−1 with Galvanostatic charging/discharging (GCD) technique and energy density (40.05 Wh/Kg) at power density (276.2 W/Kg. Furthermore, after 5000 cycles with ~ 12% retention, the as-synthesised electrodic nanocomposite shows satisfactory GCD stability without noticeable capacitance deterioration. The MnFe2O4@rGO nano-composite, as synthesised, demonstrates impressive power/energy densities and could be investigated as a potential electrode architecture for large-scale energy storage devices. © Qatar University and Springer Nature Switzerland AG 2024.
On finite-buffer batch-size-dependent bulk service queue with queue-length dependent vacation
(Taylor and Francis Ltd., 2020) G.K. Gupta; A. Banerjee; U.C. Gupta
This paper considers a single server finite-buffer batch-size-dependent bulk service queue with queue-length dependent vacation. Customers arrive at the system according to the Poisson process and are served in batches of maximum size ‘b’ with a minimum threshold value ‘a’ following the ‘general bulk service’ rule. The service time distribution is assumed to be of general type which modulates depending on serving batch size. The server is allowed to take vacation, either single or multiple vacations, whenever permissible numbers of customers are not found in the queue at the beginning of the service. The vacation time distribution is assumed to be of general type and dynamically changes depending on the queue content at vacation initiation epoch. We use the supplementary variable and the embedded Markov chain techniques to obtain the steady-state joint distribution of the queue content service batch size, queue content and type of vacation taken by the server at various epochs. Several numerical results are presented at the end to bring out the qualitative aspect of the model, which reveals the fact that queue-length dependent vacation further reduces congestion in the batch-size-dependent bulk service queues. © 2019 International Chinese Association of Quantitative Management.