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Open access

I Bhatnagar, M Singh, N Mishra, R Saxena, K Thangaraj, L Singh and S Saxena

The Latitude Wise Prevalence of the CCR5-Δ32-HIV Resistance Allele in India

The chemokine receptor CCR5 plays a crucial role during CD4-mediated entry of HIV-1 in macrophages and a 32 bp deletion in the CCR5 gene (CCR5-Δ32) confers protection against HIV infection and AIDS progression. To evaluate the contribution of this host genetic factor in aggravating India's HIV/AIDS problem, we exclusively examined the frequency of CCR5-Δ32 in 43 different ethnic endogamous Indian populations comprising 1,882 individuals and its latitude-wise distribution in India. This is the first report of prevalence and latitude-wise distribution of CCR5-Δ32 in such large scale in India, which indicates that most of the Indian populations lack the CCR5-Δ32 mutation. This mutation was exhibited in only 13 out of the 43 ethnic populations of India studied with allelic frequency 0.62 - 5%. Southward decreasing cline was observed for frequencies of CCR5-Δ32 (0.79% to 5.0% in North vs. 0.62% to 1.4% South). These results are in accordance with HIV/AIDS prevalence in India, and suggest that absence of CCR5-Δ32 mutation may be one of the important factors for HIV/AIDS incidence in India.

Open access

S. Sadana, S. Yadav, N. Jha, V. Gupta, R. Agarwal, A. Bandyopadhyay and T. Saxena

A Computer Controlled Precision High Pressure Measuring System

A microcontroller (AT89C51) based electronics has been designed and developed for high precision calibrator based on Digiquartz pressure transducer (DQPT) for the measurement of high hydrostatic pressure up to 275 MPa. The input signal from DQPT is converted into a square wave form and multiplied through frequency multiplier circuit over 10 times to input frequency. This input frequency is multiplied by a factor of ten using phased lock loop. Octal buffer is used to store the calculated frequency, which in turn is fed to microcontroller AT89C51 interfaced with a liquid crystal display for the display of frequency as well as corresponding pressure in user friendly units. The electronics developed is interfaced with a computer using RS232 for automatic data acquisition, computation and storage. The data is acquired by programming in Visual Basic 6.0. This system is interfaced with the PC to make it a computer controlled system. The system is capable of measuring the frequency up to 4 MHz with a resolution of 0.01 Hz and the pressure up to 275 MPa with a resolution of 0.001 MPa within measurement uncertainty of 0.025%. The details on the hardware of the pressure measuring system, associated electronics, software and calibration are discussed in this paper.

Open access

J. Reddy, A. Singh, S. Joshi, M. Khan and J. Saxena

Abstract

DNA topoisomerases are ubiquitous enzymes which are involved in replication, transcription, recombination and repair of nucleic acids. DNA topoisomerase II of filarial parasite Setaria cervi was purified to homogeneity by use of cation exchange and affinity chromatography. The purified enzyme migrated on SDS-PAGE as a single band with molecular weight of ∼80 kDa and native molecular weight of the enzyme was found to be 175 kDa indicating the dimeric nature of the protein. Topo II of S. cervi required ATP and dATP for its activity and optimal activity was observed at 1.0 mM ATP concentration. The filarial enzyme also utilized nucleotides, namely GTP, UTP and CTP for its activity. The divalent metal ions requirement of the enzyme showed that beside Mg+2 other ions viz., Ca+2, Mn+2, Cu+2 and Sr+2 were also utilized as cofactor for the activity. Antifilarial compounds ivermectin and diethylcarbamazine inhibited 100 % topo II activity at 100 μM concentration but suramin showed similar effect at 20 μM concentration. Nalidixic acid and novobiocin exhibited 100 % inhibition of the enzyme activity while mAMSA and etoposide inhibited the activity to different extents at 100 μM concentration. In view of significant differences in properties exhibited by the filarial topoisomerase as compared to other parasitic and eukaryotic topoisomerases, the filarial topoisomerase can be usefully exploited to devise new antifilarial compounds.

Open access

N. Saxena, S. Kumar, M.K. Sharma and S.P. Mathur

Corrosion inhibition performance of mild steel in nitric acid solution containing different concentration of anisalidine derivative Schiff bases viz. N- (4-nitro phenyl) p-anisalidine (SB1), N- (4-chloro phenyl) p-anisalidine (SB2), N- (4-phenyl) p-anisalidine (SB3), N- (4-methoxy phenyl) p-anisalidine (SB4), N- (4-hydroxy phenyl) p-anisalidine (SB5) has been investigated using mass loss, thermometric and potentiostate polarization technique. Inhibition efficiencies of Schiff bases have been evaluated at different acid strength. The inhibition efficiency was found larger than their parent amines. Inhibition efficiencies of synthesized Schiff bases increase with inhibitor concentration. Inhibition efficiency increases up to 98.32% with ansalidine derivative Schiff base.

Open access

S. Basak, Kartick. K. Samanta, S. Saxena, S.K. Chattopadhyay, R. Narkar, R. Mahangade and G.B. Hadge

Abstract

Flame retardancy was imparted in cellulosic cotton textile using banana pseudostem sap (BPS), an eco-friendly natural product. The extracted sap was made alkaline and applied in pre-mordanted bleached and mercerized cotton fabrics. Flame retardant properties of both the control and the treated fabrics were analysed in terms of limiting oxygen index (LOI), horizontal and vertical flammability. Fabrics treated with the non-diluted BPS were found to have good flame retardant property with LOI of 30 compared to the control fabric with LOI of 18, i.e., an increase of 1.6 times. In the vertical flammability test, the BPS treated fabric showed flame for a few seconds and then, got extinguished. In the horizontal flammability test, the treated fabric showed no flame, but was burning only with an afterglow with a propagation rate of 7.5 mm/min, which was almost 10 times lower than that noted with the control fabric. The thermal degradation and the pyrolysis of the fabric samples were studied using a thermogravimetric analysis (TGA), and the chemical composition by FTIR, SEM and EDX, besides the pure BPS being characterized by EDX and mass spectroscopy. The fabric after the treatment was found to produce stable natural khaki colour, and there was no significant degradation in mechanical strengths. Based on the results, the mechanism of imparting flame retardancy to cellulosic textile and the formation of natural colour on it using the proposed BPS treatment have been postulated.