A probabilistic approach for modelling the joint action of drugs

An understanding of the joint action of drugs is becoming increasingly important in a variety of scientific disciplines, ranging from pharmacology and toxicology on the one hand to industrial hygiene and environmental protection on the other. The action of even a single drug upon a biological organism involves a complex sequence of processes and if more than one drug is present, the situation is further complicated The role of mathematical models in this context is now widely recognized (Plackett & Hewlett 1952, Hewlett and Plackett, 1959, 1979, Ashford and Cobby 1974, Ashford 7981

Experiments with flowing gases in an open photoacoustic cell

A simple gas-microphone photoacoustic cell is described in which there is no sizable loss of signal on opening the cell to the atmosphere or even under conditions of gas flow. Results obtained under different rates of flow of gases and chopping frequencies are reported. Except for carbon black, the photoacoustic signal is found to be independent of flow-rate for all the solid substances studied

Analysis of M[X1],M[X2]/G1,G2/1 retrial queueing system with priority services, working breakdown, collision, Bernoulli vacation, immediate feedback, starting failure and repair

This paper considers an M[X1] , M[X2] /G1,G2/1 general retrial queueing system with priority services. Two types of customers from different classes arrive at the system in different independent compound Poisson processes. The server follows the non-pre-emptive priority rule subject to working breakdown, Bernoulli vacation, starting failure, immediate feedback, collision and repair. After completing each service, the server may go for a vacation or remain idle in the system. The priority customers who find the server busy are queued in the system. If a low-priority customer finds the server busy, he is routed to orbit that attempts to get the service. The system may become defective at any point of time while in operation. However, when the system becomes defective, instead of stopping service completely, the service is continued to the interrupted customer only at a slower rate. Using the supplementary variable technique, the joint distribution of the server state and the number of customers in the queue are derived. Finally, some performance measures are obtained

Comparative analysis of PWM techniques for Photovoltaic application with HERIC inverter

Photovoltaic inverters achieves an effective and efficient system and plays an important role in reducing the total cost of the system. The main objective  of this paper is to develope mathematical model and analyse the performance of photovoltaic fed  HERIC inverter for different Pulse-Width Modulation (PWM) techniques. The two different carrier signals such as sinusoidal carrier signal and triangular carrier signals are used. The required PWM pulses are generated by comparing the trapezoidal reference signal with those carrier signals. The simulation is carried out using MATLAB/Simulink. The performance indices used in this comparison are THD, output power, fundamental output voltage and RMS value of output voltage

INDUCED PHENOLOXIDASE PROFILES IN SILKWORM Bombyx mori (L.) UNDER BIOTIC STRESS

Phenol oxidase (PO) is one of the stress enzyme protein in living organism. The conversion of Pro-PO into an activation form of PO required a stress protein. In the present study has emerged with the novel finding of induced phenoloxidase was identified under bacterial endotoxin viz., Lipopolysaccharide (LPS) activity using silkworm Bombyx mori as an animal model. The PO enzyme plays an important role for insect survival during pathophysiological conditions. The enzyme activity was analyzed from ten different silkworm races with two phenolic substrates viz., L-Dopa and Dopamine by Native-PAGE. The bacterially induced PO was found in hemolymph and midgut of silkworm, PO3 were induced by LPS injection. In control PO1 & PO2 are non-bacterially induced protein having the molecular weight of 72 and 71. The results shown that there is no substrate specificity and similar functional activity was found in hemolymph and midgut under pathogenic condition. It was observed that bacterially inducible PO clearly differed from non-inducible PO (control). At final observation of induced isozymes of PO in the haemolymph and midgut system of tolerant silkworm races points out the existence of biochemical immunity against biotic stress of LPS. This is the first report to document the silkworm immunity under the LPS toxin in different silkworm races to identify the tolerant and susceptibility against a biotic stress

Variation in growth of peanut plants under drought stress condition and in combination with paclobutrazol and ABA

            Economically important oilseed crop peanut (Arachis hypogaea L. TVM-2) belonging to the family Fabaceae was selected for the present investigation. Field experiments were conducted to identify the variation under drought stress, paclobutrazol, and abscisic acid, and their combination on the growth of peanut plants. Drought stress decreased the morphological parameters like root length, stem length, total leaf area, fresh and dry weight on 40, 60 and 80 days after sowing (DAS) when compared to control. The paclobutrazol (PBZ) and abscisic acid (ABA) treatment to the drought stressed plants increased all the parameters when compared to drought stressed plants. PBZ treatment increased the root length when compared to control, while decreased the stem length and leaf area. ABA treated plants decreased root length, while increasing the stem length and leaf area when compared to control. Fresh and dry weight decreased in drought stressed plants when compared to control. PBZ and ABA to the drought stressed plants increased the fresh and dry weight. PBZ and ABA treatments decreased the fresh and dry weight when compared in the unstressed plants.

Virtual screening, identification and experimental testing of novel inhibitors of PBEF1/Visfatin/NMPRTase for glioma therapy

Background: Pre-B-cell colony enhancing factor 1 gene (PBEF1) encodes nicotinamide phosphoribosyltransferase (NMPRTase), which catalyses the rate limiting step in the salvage pathway of NAD+ metabolism in mammalian cells. PBEF1 transcript and protein levels have been shown to be elevated in glioblastoma and a chemical inhibitor of NMPRTase has been shown to specifically inhibit cancer cells. Methods: Virtual screening using docking was used to screen a library of more than 13,000 chemical compounds. A shortlisted set of compounds were tested for their inhibition activity in vitro by an NMPRTase enzyme assay. Further, the ability of the compounds to inhibit glioma cell proliferation was carried out. Results: Virtual screening resulted in short listing of 34 possible ligands, of which six were tested experimentally, using the NMPRTase enzyme inhibition assay and further with the glioma cell viability assays. Of these, two compounds were found to be significantly efficacious in inhibiting the conversion of nicotinamide to NAD+, and out of which, one compound, 3-amino-2-benzyl-7-nitro-4-(2-quinolyl-)-1,2-dihydroisoquinolin-1-one, was found to inhibit the growth of a PBEF1 over expressing glioma derived cell line U87 as well. Conclusions: Thus, a novel inhibitor has been identified through a structure based drug discovery approach and is further supported by experimental evidence

Padina boergessenii ameliorates carbon tetrachloride induced nephrotoxicity in Wistar rats

AbstractThis research investigates the ameliorative effect of brown alga Padina boergessenii against CCl4-induced nephrotoxicity in rats. Twenty-four Wistar albino rats were divided into four groups as follows: control group (saline), CCl4 group, CCl4+P. boergessenii extract group and P. boergessenii extract alone group. At the end of the experimental period, the animals are sacrificed and tissue samples (kidney) were collected. CCl4 at a dose of 2mL/kg, administered subcutaneously, produced significantly decreased activities of glutathione peroxidase (GSH-Px), superoxide dismutase (SOD), and catalase (CAT). Histopathological examinations showed massive centrilobular necrosis and fat accumulation in CCl4-induced animals. In the protective test, especially in animals pretreated with P. boergessenii (150mg/kg) extract, there was a significant increase in antioxidant enzyme levels although there was no sign of abnormality in the kidney of rats pretreated with extract as evidenced by histopathological sections against CCl4-induced decrease of lipid peroxidation (TBARS). The ameliorative effect may be due to the presence of various bioactive compounds in alga. These results suggest that an extract of P. boergessenii is able to significantly alleviate the nephrotoxicity induced by CCl4 in Wistar rats