5,635 research outputs found

    A new operational matrix based on Bernoulli polynomials

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    In this research, the Bernoulli polynomials are introduced. The properties of these polynomials are employed to construct the operational matrices of integration together with the derivative and product. These properties are then utilized to transform the differential equation to a matrix equation which corresponds to a system of algebraic equations with unknown Bernoulli coefficients. This method can be used for many problems such as differential equations, integral equations and so on. Numerical examples show the method is computationally simple and also illustrate the efficiency and accuracy of the method

    Susceptibility of Leishmania major to Veronica persica Poir. extracts - In vitro and in vivo assays

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    Leishmania major is an intracellular parasite generally responsible for cutaneous leishmaniasis (CL), one of the most encountered skin diseases especially in Pakistan, Iran, Iraq, and Saudi Arabia. Current treatment options are not ideal, due to unwanted side effects and increasing resistance and availability is often limited in developing countries. Medicinal plants continue to attract attention because of their beneficial effects in the prevention or/and accelerating the healing process of various diseases. In this study, in vitro and in vivo susceptibility of L. major to Veronica persica Poir. extract, a medicinal plant with many applications, has been evaluated. Antileishmanial activity of plant extract was investigated both on cultured L. major promastigotes and in mice challenged with L. major. Animals were divided into three groups including control (without any treatment), test (treated with plant extract) and glucantime (the reference drug) treated groups. After treatments, skin lesion sizes and body weights of animals were checked during 4 weeks. The potential of the plant extract in decreasing the number of parasites in spleen cells of animals as well as inducing the nitric oxide (NO) production by macrophage cells was also investigated. In vitro tests showed that the plant extract was able to reduce the survival time of promastigotes in a concentration-dependent manner. In vivo experiments also revealed a significant influence of V. persica extracts on accelerating the healing process as well as reducing the overall disease burden in animal model by inducing NO production in macrophage cells. Our findings indicated the promising potential of V. persica extract as an ideal candidate in the treatment of CL caused by L. major

    Topological Measure Locating the Effective Crossover between Segregation and Integration in a Modular Network

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    We introduce an easily computable topological measure which locates the effective crossover between segregation and integration in a modular network. Segregation corresponds to the degree of network modularity, while integration is expressed in terms of the algebraic connectivity of an associated hyper-graph. The rigorous treatment of the simplified case of cliques of equal size that are gradually rewired until they become completely merged, allows us to show that this topological crossover can be made to coincide with a dynamical crossover from cluster to global synchronization of a system of coupled phase oscillators. The dynamical crossover is signaled by a peak in the product of the measures of intra-cluster and global synchronization, which we propose as a dynamical measure of complexity. This quantity is much easier to compute than the entropy (of the average frequencies of the oscillators), and displays a behavior which closely mimics that of the dynamical complexity index based on the latter. The proposed toplogical measure simultaneously provides information on the dynamical behavior, sheds light on the interplay between modularity vs total integration and shows how this affects the capability of the network to perform both local and distributed dynamical tasks

    In vitro and in vivo assessment of free radical scavenging and antioxidant activities of Veronica persica Poir

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    With the appearance of new disorders along with inability of some conventional therapies for the treatment of diseases without any side effects, the discovery of safe and efficient therapeutic agents is of utmost importance in the medical area. In this context, medicinal plants as promising therapeutic candidates can provide a reliable and efficient profile. Since free radicals are at the center of various disorder pathways, reducing their production or complete removal of these chemical species could be advantageous for prevention and treatment of many diseases. In this experiment, free radical scavenging and antioxidant activities of Veronica persica Poir., a known medicinal plant, were evaluated using in vitro and in vivo assays. Chemical characterization results showed a high phenolic content in the V. persica methanol extract. In addition, in vitro assays including DPPH radical-scavenging assay, nitric oxide-scavenging activity assay, hydrogen peroxide scavenging test and bleomycin-dependent DNA damage test revealed significant antioxidant power and radical scavenging capacity of this plant. In accordance, in vivo experiments showed inhibitory effects of the methanol extract on lipid peroxidation, a main cause of cell damage. Our findings revealed the promising potential of this plant in reducing free radicals through different pathways. Moreover, our data suggested a correlation between the high phenolic content of the V. persica extract and its free radical scavenging and antioxidant activities

    Pullulan gum production from low-quality fig syrup using Aureobasidium pullulans

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    Pullulan is an important polysaccharide with several potential applications in food science, pharmaceutical and cosmetic industries, but high costs of pullulan production are the main limitation for commercial utilization. Therefore, a cost-effective process for pullulan production was developed using fig syrup as an exclusive nutrient source. In particular, the feasibility of using low quality fig syrup as a supplemental substrate for pullulan gum production by Aureobasidium pullulans was investigated. Fermentation was carried out over a range of fig syrup and sucrose degrees Brix (5-15%). Maximum pullulan gum production was observed after 96h using 12.5% fig syrup, yielding approximately14.06 g/L. This value of pullulan production (14.06 g/L) was higher than the amount of pullulan produced using sucrose as substrate (5.01 g/L). In conclusion, fig syrup was an effective substrate for pullulan production by Aureobasidium pullulans, and, therefore, this byproduct deserves attention for the cost-effective and environmentally friendly pullulan production
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