The W 2 -curvature tensor on warped product manifolds and applications

The purpose of this paper is to study the W2-curvature tensor on (singly) warped product manifolds as well as on generalized Robertson-Walker and standard static space-times. Some different expressions of the W2-curvature tensor on a warped product manifold in terms of its relation with W2-curvature tensor on the base and fiber manifolds are obtained. Furthermore, we investigate W2-curvature flat warped product manifolds. Many interesting results describing the geometry of the base and fiber manifolds of a W2-curvature flat warped product manifold are derived. Finally, we study the W2-curvature tensor on generalized Robertson-Walker and standard static space-times; we explore the geometry of the fiber of these warped product space-time models that are W2-curvature flat. © 2016 World Scientific Publishing Company

2-Killing vector fields on warped product manifolds

This paper provides a study of 2-Killing vector fields on warped product manifolds as well as characterization of this structure on standard static and generalized Robertson-Walker space-times. Some conditions for a 2-Killing vector field on a warped product manifold to be parallel are obtained. Moreover, some results on the curvature of a warped product manifolds in terms of 2-Killing vector fields are derived. Finally, we apply our results to describe 2-Killing vector fields of some well-known warped product space-time models. © 2015 World Scientific Publishing Company

O efeito das propriedades antioxidantes do extrato aquoso do alho e da Nigella sativa como agentes anti-esquistossômicos no camundongo

The aim of this study was to assess the antioxidant and anti-schistosomal activities of the garlic extract (AGE) and Nigella sativa oil (NSO) on normal and Schistosoma mansoni-infected mice. AGE (125 mg kg-1, i.p.) and NSO (0.2 mg kg-1, i.p.) were administrated separately or in combination for successive 28 days, starting from the 1st day post infection (pi). All mice were sacrificed at weeks 7 pi. Hematological and biochemical parameters including liver and kidney functions were measured to assess the progress of anemia, and the possibility of the tissue damage. Serum total protein level, albumin, globulin and cholesterol were also determined. Malondialdehyde (MDA) and glutathione (GSH) levels were determined in the liver tissues as biomarkers for oxidative and reducing status, respectively. The possible effect of the treatment regimens on Schistosoma worms was evaluated by recording percentage of the recovered worms, tissue egg and oogram pattern. Result showed that, protection with AGE and NSO prevented most of the hematological and biochemical changes and markedly improved the antioxidant capacity of schistosomiasis mice compared to the infected-untreated ones. In addition, remarkable reduction in worms, tissue eggs and alteration in oogram pattern were recorded in all the treated groups. The antioxidant and antischistosomal action of AGE and NSO was greatly diverse according to treatment regimens. These data point to these compounds as promising agents to complement schistosomiasis specific treatment.O propósito deste estudo foi verificar os efeitos anti-oxidantes e anti-esquistossômicos do extrato de alho (AGE) e do óleo da Nigella sativa (NSO) em camundongos normais e infectados com S. mansoni. AGE (125 mg/kg, i.p. ) e NSO (0,2 mg/kg, i.p.) foram administrados separadamente ou em combinação por 28 dias sucessivos começando do primeiro dia pós infecção (p.i.). Todos os camundongos foram sacrificados sete semanas p.i. Parâmetros hematológicos e bioquímicos incluindo funções renais e hepáticas foram medidos para avaliar o progresso da anemia e a possibilidade de dano tecidual. O nível total de proteínas séricas, albumina, globulina e colesterol foram também medidos. Níveis de malondialdeído (MDA) e glutationa (GSH) foram determinados em tecido hepático como biomarcações para o estado oxidativo e redutor, respectivamente. O possível efeito dos tratamentos sobre os vermes de Schistosoma foram avaliados através do percentual de vermes recuperados, ovos no tecido e o oograma. Resultados mostraram que a proteção com AGE e NSO preveniu a maior parte das alterações hematológicas e bioquímicas e melhoraram bastante a capacidade anti-oxidante de camundongos com esquistossomose comparados com aqueles infectados e não tratados. Adicionalmente, foi registrado uma acentuada redução nos vermes, ovos no tecido e alterações do oograma. A ação anti-oxidante e anti-esquistossômica do AGE e NSO foi diferente de acordo com os vários tratamentos. Estes dados mostram que estes compostos são agentes promissores para complementar o tratamento específico da esquistossomose

Cleome droserifolia tem atividade anti-esquistossomose mansônica?

The present study was undertaken to assess the effect of the crude extract of Cleome droserifolia (CD) leaves on experimentally infected mice with Schistosoma mansoni. Two groups of mice, showing a patent infection of S. mansoni, one of them was daily treated with an alcoholic extract of CD leaves (0.31 g kg-1 body weight, i.p.) for 21 days. The schistosomicidal activity of the CD extract was evaluated, three weeks post-treatment, on some parasitological and histopathological aspects including worm load, oogram pattern, faecal eggs releasing and granuloma formation. In addition, serum thyroid hormones levels (tri-iodothyronine; T3 and tetra-iodo-thyronin; T4), serum total protein contents and hepatic reduced glutathione (GSH) were evaluated. Treatment using CD extract resulted in a weak reduction in worm burden (32.46%) and affected the viability of both mature and immature eggs as indicated by the increase in the percentage of dead eggs and the decrease in the percentage of live ones. In addition, a week post-treatment, eggs elimination was observed in the stool of the infected-treated group which was low compared to the infected group. There was a suppressive effect of the extract on granuloma formation that could be due to the antioxidant effect of the extract. These data are confirmed by increasing hepatic GSH, serum total proteins and thyroid hormone levels in the infected-treated group as compared to the infected group. Treatment significantly enhanced b globulin fractions of the protein. Based on these assumptions, CD extract has beneficial effects on thyroid hormones status and anti-schistosomiasis activity. The beneficial effects of CD extract could be related to its direct effects on the parasite, and secondary to its effect on the antioxidant capacity of the host. The present study could emphasize the precise mechanism (s) of CD extract protection.O presente estudo foi realizado para verificar o efeito do extrato cru de folhas de Cleome droserifolia (CD) em camundongos experimentalmente infectados com Schistosoma mansoni. Em dois grupos de camundongos mostrando infecção patente por S. mansoni, um deles foi tratado diariamente com extrato alcoólico de folhas de CD (0.31g kg-1 por peso corporal, i.p.) por 21 dias. A atividade esquistossomicida do extrato de CD foi avaliada, três semanas após o tratamento, em alguns aspectos parasitológicos e histopatológicos incluindo carga parasitária, padrão de oograma, eliminação fecal de ovos e formação de granuloma. Além disto, níveis séricos de hormônio tireoideano (tri-iodotironina: T3 e tetra-iodotironina: T4), conteúdo sérico total de proteínas e glutatione hepático reduzido (GSH) foram avaliados. Tratamento usando extrato de CD resultou em fraca redução da carga de vermes (32,46%) e afetou a viabilidade de ovos maduros ou não, como indicado pelo aumento na porcentagem de ovos mortos e o descrécimo na porcentagem de ovos viáveis. Além disso, uma semana após o tratamento, a eliminação de ovos foi observada nas fezes do grupo infectado-tratado que foi baixa comparada ao grupo infectado. Houve efeito supressivo do extrato sobre a formação de granuloma que poderia ser devido ao efeito antioxidante do extrato. Estes dados são confirmados pelo aumento do GSH hepático, soro total de proteínas e níveis dos hormônios tireoideanos no grupo infecto-tratado quando comparado com o grupo infectado. O tratamento aumentou significativamente as frações beta-globulina da proteína. Baseado nestas afirmativas o extrato de CD tem efeitos benéficos sobre o nível dos hormônios tireoideanos e da atividade anti-esquistossomica. Os efeitos benéficos do extrato de CD poderiam estar relacionados com seu efeito direto sobre o parasita, e secundariamente por seus efeitos na capacidade anti-oxidante do hospedeiro. O presente trabalho poderia enfatizar o(s) mecanismo(s) preciso(s) desta proteção do extrato de CD

Purification of kappa (k)-carrageenase from locally isolated Cellulosimicrobium cellulans

Partial purification of the crude kappa (k)-carrageenase present in the culture filtrates of Cellulosimicrobium cellulans was carried out by fractional precipitation, using ammonium sulphate, acetone and ethanol individually. The highest recovered protein (37.08%) combined with enzyme activity was obtained with ammonium sulphate. The fraction precipitated by 90% ammonium sulphate was re-purified by anion exchange chromatography diethylaminoethyl (DEAE) cellulose, A-52 and 79 fractions were obtained. The loaded protein was separated into 4 peaks. The third protein peak was the major one which contained the most recovered enzyme activity (84.95%) from the eluted fractions. The collected fractions of this peak were subjected to further purification by re-chromatography on Sephadex G-100. The k-carrageenase activity was fractionated into 2 peaks. The first peak was the major one containing 95.622% of the total recovered activity. The pooled fractions of the major protein component showed a specific k-carrageenase activity of 46.22 U/mg protein, yielding about 4.6 fold purification of the crude enzyme preparation. Some properties of purified k-carrageenase obtained from cellusimicrobium cellulans cultures were studied. The optimum reaction temperature of the purified k-carrageenase was 30°C and the maximum activity occurred at a reaction pH of 6.Key words: Cellulosimicrobium cellulans, k-carrageenase, purification, sephadex G-100, diethylaminoethyl (DEAE) sephadex A-52

Economic Analysis of Stand-Alone Hybrid Wind/PV/Diesel Water Pumping System: A Case Study in Egypt

The design and evaluation of a stand-alone hybrid renewable energy system for pumping underground water for small farm irrigation is presented. Given environmental conditions, system specifications and daily load demand data, the optimal size of main system components is obtained using a sizing algorithm. Different renewable energy systems are compared using yearly simulations, on hourly base via specialized commercial software simulation packages PVSYST and HOMER, to simulate the system performance and to reach the optimum configurations based on the objective criteria. The criteria used in economic optimization are the net present cost and the cost of energy, with the percent of the capacity shortage. The following systems can be compared: PV only, PV with horizontal axis wind turbine, PV with vertical axis wind turbine, and PV with horizontal axis wind turbine and diesel generator and diesel generator only. The simulation also was carried out for different load patterns for optimum operation. The study was illustrated for climatic conditions of an isolated area in El-Tour City, Sinai, Egypt. The installed 3.42 kW PV water pumping system for irrigation purposes in the same site was also described

Synthesis and biological activity of naphtho[1,2,6,5]pyrano[3,4-f]phthalazine- 4, 14-diones

415-41

Neutralizing activities of caprine antibodies towards conserved regions of the HCV envelope glycoprotein E2

Anti HCV vaccine is not currently available and the present antiviral therapies fail to cure approximately half of the treated HCV patients. This study was designed to assess the immunogenic properties of genetically conserved peptides derived from the C-terminal region of HVR-1 and test their neutralizing activities in a step towards developing therapeutic and/or prophylactic immunogens against HCV infection. Antibodies were generated by vaccination of goats with synthetic peptides derived from HCV E2. Viral neutralizing capacity of the generated anti E2 antibodies was tested using in vitro assays. Goats immunized with E2 synthetic peptides termed p412 [a.a 412-419], p430 [a.a 430-447] and p517 [a.a 517-531] generated high titers of antibody responses 2 to 4.5 fold higher than comparable titers of antibodies to the same epitopes in chronic HCV patients. In post infection experiments of native HCV into cultured Huh7.5 cells anti p412 and anti p 517 were proven to be neutralizing to HCV genotype 4a from patients' sera (87.5% and 75% respectively). On the contrary anti p430 exhibited weak viral neutralization capacity on the same samples (31.25%). Furthermore Ab mixes containing anti p430 exhibited reduced viral neutralization properties. From these experiments one could predict that neutralization by Abs towards different E2-epitopes varies considerably and success in the enrichment of neutralization epitope-specific antibodies may be accompanied by favorable results in combating HCV infection. Also, E2 conserved peptides p517 and p412 represent potential components of a candidate peptide vaccine against HCV infection