810 research outputs found

    Wave reflection at a free interface in an anisotropic pyroelectric medium with nonclassical thermoelasticity

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    In this paper, the well-established two-dimensional mathematical model for linear pyroelectric materials is employed to investigate the reflection of waves at the boundary between a vacuum and an elastic, transversely isotropic, pyroelectric material. A comparative study between the solutions of (a) classical thermoelasticity, (b) Cattaneo–Lord–Shulman theory and (c) Green–Lindsay theory equations, characterised by none, one and two relaxation times, respectively, is presented. Suitable boundary conditions are considered in order to determine the reflection coefficients when incident elasto–electro–thermal waves impinge the free interface. It is established that, in the quasi-electrostatic approximation, three different classes of waves: (1) two principally elastic waves, namely a quasi-longitudinal Primary (qP) wave and a quasi-transverse Secondary (qS) wave; and (2) a mainly thermal (qT) wave. The observed electrical effects are, on the other hand, a direct consequence of mechanical and thermal phenomena due to pyroelectric coupling. The computed reflection coefficients of plane qP waves are found to depend upon the angle of incidence, the elastic, electric and thermal parameters of the medium, as well as the thermal relaxation times. The special cases of normal and grazing incidence are also derived and discussed. Finally, the reflection coefficients are computed for cadmium selenide observing the influence of (1) the anisotropy of the material, (2) the electrical potential and (3) temperature variations and (4) the thermal relaxation times on the reflection coefficients

    COMPARATIVE PHYTOCHEMICAL AND BIOLOGICAL INVESTIGATION OF FIVE GLYCINE MAX (L.) MERRILL GENOTYPES

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    Objective: Soybean (Glycine max L. Merrill) is the world’s most important consumed seed legume. The objectives of the present study were to determine the variability in phytochemical composition and biological activities between five genotypes of G. max. Methods: Lipoidal matters were determined using glucose (GLC). Amino acids were detected by the amino acid analyzer. The phytoconstituents present within each ethanol extract was investigated by gas chromatography-mass spectrometry. The amount of total phenolics, flavonoids, and tannins was analyzed using a spectrophotometric technique, based on Folin–Ciocalteu reagent, aluminum chloride colorimetric assay, and the modified vanillin hydrochloric acid method, respectively. Quercetin, catechin, and gallic acid were used as standard compounds, respectively. Isoflavones content were detected by high-performance liquid chromatography (HPLC)/photodiode array (PDA). The radical scavenging and antioxidant capacity of the genotypes using different in vitro analytical assays such as 2,2-diphenyl,1-picryl hydrazyl, 2,2’-Azino-bis(3-ethylbenzothiazoline-6-sulphonic acid, reducing power, metal chelating, and ferric reducing anti-oxidant power. Butyl hydroxyl toluene and trolox were used as the reference antioxidant radical scavenger compounds. Antitumor activity was evaluated by detecting the viability of Ehrlich ascites carcinoma cells on four different concentrations (1–5 mg/mL). Results: GLC analysis showed the high value of total unsaturated fatty acids and 16 amino acids including glutamic acid with the highest concentration. The variation between genotypes according to their chemical composition of the aldehydes, esters, ketones, alcoholics, and carboxylic content were reported. HPLC/PDA referred to the presence of daidzein, genistein, and in all genotypes. Conclusion: The results confirm the higher value of phytoconstituents of the genotype Giza 35 and Giza 21 as well as their better bioactivity

    Proteomic analysis of Glossina pallidipes salivary gland hypertrophy virus virions for immune intervention in tsetse fly colonies

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    Many species of tsetse flies (Diptera: Glossinidae) can be infected by a virus that causes salivary gland hypertrophy (SGH). The viruses isolated from Glossina pallidipes (GpSGHV) and Musca somestica (MdSGHV) have recently been sequenced. Tsetse flies with SGH have a reduced fecundity and fertility which cause a serious problem for mass rearing in the frame of sterile insect technique (SIT) programs to control and eradicate tsetse populations in the wild. A potential intervention strategy to mitigate viral infections in fly colonies is neutralizing of the GpSGHV infection with specific antibodies against virion proteins. Two major GpSGHV virion proteins of about 130 kDa and 50 kDa, respectively, were identified by Western analysis using polyclonal rabbit antibody raised against whole GpSHGV virions. The proteome of GpSGHV, containing the antigens responsible for the immune-response, was investigated by liquid chromatography tandem mass spectrometry (LC-MS/MS) and 61 virion proteins were identified by comparison with the genome sequence. Specific antibodies were produced in rabbits against seven candidate proteins including the ORF10 / C-terminal fragment, ORF47 and ORF96 as well as proteins involved in peroral infectivity PIF-1 (ORF102), PIF-2 (ORF53), PIF-3 (ORF76) and P74 (ORF1). Antiserum against ORF10 specifically reacted to the 130 kDa protein in a Western blot analysis and to the envelope of GpSGHV using immunogold-EM. This result suggests that immune intervention of viral infections in colonies of G. pallidipes is a realistic optio

    Variability and inheritance of okra leaf- shape of cotton cv. Sudac-k in different genetic backgrounds

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       Okra leaf- shape is an important trait in cotton. Sudac-k is the only cotton variety with okra leaf type in the Sudan. The objectives of the study were to analyze the inheritance of the okra leaf of Sudac-k and its expression in different genetic backgrounds. The experiment was carried out for two seasons (2004/05 and 2005/06) and one off-season in 2006 at Gezira Research Farm of the Agricultural Research Corporation (ARC), Wad Medani, Sudan. The plant material consisted of Sudac-k and nine different varieties; B-pima, Barakat-90, G.S, Maryoud, Shambat-B, Acala-M, Acala-H, Barac (67) B and Albar (57)12. Eighteen reciprocal F1s were produced between Sudac-k and respective cultivars. In the second season, F2 ҆s, backcrosses and F3 plants were (Sudac-k X Albar (57)12). At maturity, individual plants were visually scored according to the leaf-shape into okra and normal leaf shape. Okra leaf morphology, lobe length, width and angle were measured in fully expanded 5- lobed leaf. It was observed that the okra leaf of Sudac-k had deep sinuses and narrow lobes while in F1 ҆ s, the sinuses were shorter and the lobes were broader. The okra leaf started at seedling stage with three lobes at the 3rd to 4th node and reached a maximum of 5 lobes at node 6 to 8 in Sudac-k, F1 plants and their progenies. Chi-square test for the segregation of leaf type in F2 indicated no significant differences among all F1 ҆ s between Sudac-k and the varieties in the distribution of okra and normal which followed the ratio of 1:2:1. This indicates that the okra leaf trait is conditioned by a single partially dominant gene. Significant differences were observed among the F1 hybrids for the expression of leaf lobing depth, lobe width and angle, indicating the effect of the genetic background on the expression of these parameters. The information will be useful in designing strategy for breeding of cotton varieties with suitable size of okra leaf to maximize its utilization in integrated insect pest management

    Use of some plant essential oils as post-harvest botanical fungicides in the management of anthracnose disease of mango fruits (Mangifera indica L.) caused by Colletotrichum gloeosporioides

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    Abstract Mango suffers fro m several diseases at all stages of its life. Anthracnose, caused by the fungus Colletotrichum gleosporioides is the most important post harvest disease of mango. The aim of this study was to test the possibility of the use of some plant essential oils i.e. Basel oil (Ocimum basilicum), Orange oil (Citrus sinensis), Lemon oil (Citrus Medica) and Mustard oil (Brassica juncea L.) to reduce postharvest losses induced by Colletotrichum gloeosporioides (Penz.) in mango fruits. In this study, the antifungal activity of essential oils under in vitro condition were assayed by tested various concentrations (0, 50,100 and 150µg/ ml)) and under in vivo condition by used different essential oil concentrations (0, 250,500 and 1000pp m) on inoculated mango fruits. Results of the present study showed that orange oil at all tested concentrations were a significant reducing the fungal linear growth if co mpared with other tested essential oils. At low concentration 50 (µg/ ml) orange oil caused 10.0% reduction in fungal growth, while at 100 (µg/ ml) caused 72.2% and at high tested concentration 150 (µg/ ml) caused a comp lete reduction in myceliu m linear growth of pathogenic fungus. Meanwhile, at low tested concentration 50 (µg/ ml), mustard oil caused a highly significantly reduction of the percentage of fungal spore germination by 70.8 % followed by basil oil by 64.7%. Results of in vivo studies showed that, at low concentration 250 ppm, mustard oil caused a highly reduction of anthracnose incidence of mango fru its by 79.9% fo llo wed by basil o il with 66.7% .On the other hand, orange and lemon oil at low concentration (250ppm) were showed a highly effect to reducing the percentage of rotting fruit tissue by 84.5 and 75.0%, respectively if co mpared with other treat ments and un-treated fruits

    Effect of heat and mass transfer and rotation on peristaltic flow through a porous medium with compliant walls

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    Purpose: The purpose of this paper is to investigate the peristaltic flow of an incompressible Newtonian fluid in a channel with compliant walls. The effects of rotation and heat and mass transfer are also taken into account. The governing equations of two dimensional fluid have been simplified under long wavelength and low Reynolds number approximation. An exact solutions is presented for the stream function, temperature, concentration field, velocity and heat transfer coefficient. Design/methodology/approach: The effect of the concentration distribution, heat and mass transfer and rotation on the wave frame are analyzed theoretically and computed numerically. Numerical results are given and illustrated graphically in each case considered. Comparison was made with the results obtained in the presence and absence of rotation and heat and mass transfer. Findings: The results indicate that the effect of the permeability and rotation are very pronounced in the phenomena. Originality/value: The objective of the present analysis is to analyze the effects of rotation, heat and mass transfer and compliant walls on the peristaltic flow of a viscous fluid

    Equation of state for β\beta-stable hot nuclear matter

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    We provide an equation of state for hot nuclear matter in β\beta-equilibrium by applying a momentum-dependent effective interaction. We focus on the study of the equation of state of high-density and high-temperature nuclear matter, containing leptons (electrons and muons) under the chemical equilibrium condition in which neutrinos have left the system. The conditions of charge neutrality and equilibrium under β\beta-decay process lead first to the evaluation of proton and lepton fractions and afterwards of internal energy, free energy, pressure and in total to the equation of state of hot nuclear matter. Thermal effects on the properties and equation of state of nuclear matter are assesed and analyzed in the framework of the proposed effective interaction model. Special attention is dedicated to the study of the contribution of the components of β\beta-stable nuclear matter to the entropy per particle, a quantity of great interest for the study of structure and collapse of supernova.Comment: 28 pages, 18 figure

    The Antiviral Drug Valacyclovir Successfully Suppresses Salivary Gland Hypertrophy Virus (SGHV) in Laboratory Colonies of Glossina pallidipes

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    Many species of tsetse flies are infected with a virus that causes salivary gland hypertrophy (SGH) symptoms associated with a reduced fecundity and fertility. A high prevalence of SGH has been correlated with the collapse of two laboratory colonies of Glossina pallidipes and colony maintenance problems in a mass rearing facility in Ethiopia. Mass-production of G. pallidipes is crucial for programs of tsetse control including the sterile insect technique (SIT), and therefore requires a management strategy for this virus. Based on the homology of DNA polymerase between salivary gland hypertrophy virus and herpes viruses at the amino acid level, two antiviral drugs, valacyclovir and acyclovir, classically used against herpes viruses were selected and tested for their toxicity on tsetse flies and their impact on virus replication. While long term per os administration of acyclovir resulted in a significant reduction of productivity of the colonies, no negative effect was observed in colonies fed with valacyclovir-treated blood. Furthermore, treatment of a tsetse colony with valacyclovir for 83 weeks resulted in a significant reduction of viral loads and consequently suppression of SGH symptoms. The combination of initial selection of SGHV-negative flies by non-destructive PCR, a clean feeding system, and valacyclovir treatment resulted in a colony that was free of SGH syndromes in 33 weeks. This is the first report of the use of a drug to control a viral infection in an insect and of the demonstration that valacyclovir can be used to suppress SGH in colonies of G. pallidipes

    PREPARATION AND EVALUATION OF CHEMICALLY INACTIVATED SALMONELLA ENTERITIDIS VACCINE IN CHICKENS

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      Objective: Salmonella enteritidis ghosts (SEGs) is a non-living empty bacterial cell envelopes which were generated using a different concentration of sodium hydroxide (NaOH) 6.4 mg/mL and evaluated as a vaccine candidate in specific pathogen-free (SPF) chicken. SEGs have been produced by chemical-mediated lysis and evaluated the potential efficacy of chemically induced SEG vaccine and its ability to induce protective immune responses against virulent S. enteritidis challenge in SPF chickens.Methods: SPF chickens were divided into three groups: Group A (non-vaccinated control), Group B (vaccinated with prepared vaccine), and Group C (vaccinated with commercial vaccine).Results: Vaccination of SPF chicken with SEGs induced higher immune responses before and after virulent challenge. SPF chicken vaccinated with SEGs showed increasing in serum enzyme-linked immunosorbent assay (ELISA) antibodies. During the vaccination period, Groups B and C showed higher serum antibody titer compared to Group A. The minimal inhibitory concentration (MIC) of NaOH was capable of inducing non-living SEGs, and it has successfully generated non-living SEGs by MIC of NaOH.Conclusion: It is a one-step process which means easy manufacturing and low production cost compared to protein E-mediated lysis method. Chemically induced SEG vaccine is a highly effective method for inducing protective immunity. This study strongly suggests that SEGs will be a permissive vaccine, as the method of inhibition of S. enteritidis was safe and cheaper than other methods, and it gave a good protection

    The Spermatophore in Glossina morsitans morsitans: Insights into Male Contributions to Reproduction.

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    Male Seminal Fluid Proteins (SFPs) transferred during copulation modulate female reproductive physiology and behavior, impacting sperm storage/use, ovulation, oviposition, and remating receptivity. These capabilities make them ideal targets for developing novel methods of insect disease vector control. Little is known about the nature of SFPs in the viviparous tsetse flies (Diptera: Glossinidae), vectors of Human and Animal African trypanosomiasis. In tsetse, male ejaculate is assembled into a capsule-like spermatophore structure visible post-copulation in the female uterus. We applied high-throughput approaches to uncover the composition of the spermatophore in Glossina morsitans morsitans. We found that both male accessory glands and testes contribute to its formation. The male accessory glands produce a small number of abundant novel proteins with yet unknown functions, in addition to enzyme inhibitors and peptidase regulators. The testes contribute sperm in addition to a diverse array of less abundant proteins associated with binding, oxidoreductase/transferase activities, cytoskeletal and lipid/carbohydrate transporter functions. Proteins encoded by female-biased genes are also found in the spermatophore. About half of the proteins display sequence conservation relative to other Diptera, and low similarity to SFPs from other studied species, possibly reflecting both their fast evolutionary pace and the divergent nature of tsetse's viviparous biology
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