98 research outputs found

    Parametric test of a zirconium (4) oxide-polyacrylic acid dual layer hyperfiltration membrane with spacecraft washwater

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    Performance data consisting of solute rejections and product flux were measured, as dependent on the operation parameters. These parameters and ranges were pressure (500,000 n/m2 to 700,000 n/m2), temperature (74 C to 95 C), velocity (1.6 M/sec to 10 M/sec), and concentration (up to 14x). Tests were carried out on analog washwater. Data presented include rejections of organic materials, ammonia, urea, and an assortment of ions. The membrane used was deposited in situ on a porcelain ceramic substrate

    Comparison Between Different Algorithms for Maximum PPT in Photovoltaic Systems and its Implementation on Microcontroller

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    This paper presents the practical implementation of fuzzy logic control algorithm for maximum power point tracking (MPPT) in photovoltaic (PV) systems. A prototyping PV system is implemented with a boost DC-DC converter using Microchip® PIC18F452 microcontroller to execute the MPPT algorithms. The common algorithms like perturbation and observation (P&O) and incremental conductance (IncCon.) as well as the proposed fuzzy logic control algorithm are implemented and tested under different conditions, and the test results are analyzed and compared. The results show that the proposed fuzzy logic control algorithm can give better performance than perturbation and observation and incremental conductance algorithms. Keywords: Photovoltaic, Maximum power point tracking, Fuzzy logic control, Microcontrollers

    Tamoxifen for treatment of abnormal uterine bleeding in etonorgstrel implant users: a randomized clinical trial

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    Background: The current study aims to compare the use of tamoxifen and oral contraceptive pills in women using implanon and complain with irregular uterine bleeding.Methods: Women attended family planning clinic using implanon presented by bleeding were invited to participate in the study. They were randomized into two groups: Group A: 100 women received Tamoxifen 10 mg twice daily for 10 days taken at the onset of an episode of bleeding or spotting episode. Group B: 100 women received Combined oral contraceptive pills (microcept) once daily for 21 days take at the onset of an episode of bleeding or spotting episode.Results: No difference regarding the baseline criteria of both groups. No difference between both groups regarding the duration of irregular bleeding in the implanon users (p=0.090). Additionally, the number of bleeding days and spotting in the last month was similar in both groups (p=0.554). The percentage of women who stopped bleeding during the period of treatment is 84% in the tamoxifen group and 92% in the COCs group, but the COCs needs longer treatment time, where the mean of days required to stop bleeding is 5.03±1.8 days in the tamoxifen group and 6.5±2.5 in the COCs group. Headache and nausea were the most prominent adverse effects found in the COCs group (p=0.000).Conclusions: Oral administration of tamoxifen 10 mg twice daily for 10 days is effective on stopping bleeding attacks in implanon users

    Metabolomic profile, anti-trypanosomal potential and molecular docking studies of <i>Thunbergia grandifolia</i>

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    Trypanosomiasis is a protozoan disease transmitted via Trypanosoma brucei. This study aimed to examine the metabolic profile and anti-trypanosomal effect of methanol extract of Thunbergia grandifolia leaves. The liquid chromatography-high resolution electrospray ionisation mass spectrometry (LC-HRESIMS) revealed the identification of fifteen compounds of iridoid, flavonoid, lignan, phenolic acid, and alkaloid classes. The extract displayed a promising inhibitory activity against T. brucei TC 221 with MIC value of 1.90 μg/mL within 72 h. A subsequent in silico analysis of the dereplicated compounds (i.e. inverse docking, molecular dynamic simulation, and absolute binding free energy) suggested both rhodesain and farnesyl diphosphate synthase as probable targets for two compounds among those dereplicated ones in the plant extract (i.e. diphyllin and avacennone B). The absorption, distribution, metabolism, excretion, and toxicity (ADMET) profiling of diphyllin and avacennone were calculated accordingly, where both compounds showed acceptable drug-like properties. This study highlighted the antiparasitic potential of T. grandifolia leaves

    Biocompatibility and application of carbon fibres in heart valve tissue engineering

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    The success of tissue engineered heart valves relies on a balance between polymer degradation, appropriate cell repopulation and ECM deposition, in order for the valves to continue their vital function. However, the process of remodelling is highly dynamic and species dependent. Carbon fibres have been well used in the construction industry for their high tensile strength and flexibility, and therefore might be relevant to support tissue engineered hearts valve during this transition in the mechanically demanding environment of the circulation. The aim of this study was to assess the suitability of carbon fibres to be incorporated into tissue engineered heart valves, with respect to optimising their cellular interaction and mechanical flexibility during valve opening and closure. The morphology and surface oxidation of the carbon fibres was characterised by scanning electron microscopy (SEM). Their ability to interact with human adipose derived stem cells (hADSCs) was assessed with respect to cell attachment and phenotypic changes. hADSCs attached and maintained their expression of stem cell markers with negligible differentiation to other lineages. Incorporation of carbon fibres into a stand-alone tissue engineered aortic root, comprised of jet-sprayed poly-caprolactone aligned fibres had no negative effects on the opening and closure characteristics of the valve when simulated in a pulsatile bioreactor. In conclusion, carbon fibres were found to be conducive to hADSC attachment and maintaining their phenotype. Carbon fibres were sufficiently flexible for full motion of valvular opening and closure. This study provides a proof of concept for the incorporation of carbon fibres into tissue engineered heart valves to continue their vital function during scaffold degradation

    Assessment of seminal plasma laminin in fertile and infertile men

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    Abstract Aim: To assess laminin levels in the seminal plasma of infertile and fertile men, and to analyze the correlation of laminin levels with sperm count, age, sperm motility and semen volume. Methods: One hundred and twenty-five recruited men were equally divided into five groups according to their sperm concentration and clinical examination: fertile normozoospermia, oligoasthenozoospermia, non-obstructive azoospermia (NOA), obstructive azoospermia (OA) and congenital bilateral absent vas deferens (CBAVD). The patients&apos; medical history was investigated and patients underwent clinical examination, conventional semen analysis and estimation of seminal plasma laminin by radioimmunoassay. Results: Seminal plasma laminin levels of successive groups were: 2.82 ± 0.62, 2.49 ± 0.44, 1.77 ± 0.56, 1.72 ± 0.76, 1.35 ± 0.63 U/mL, respectively. The fertile normozoospermic group showed the highest concentration compared to all infertile groups with significant differences compared to azoospermic groups (P &lt; 0.05). Testicular contribution was estimated to be approximately one-third of the seminal laminin. Seminal plasma laminin demonstrated significant correlation with sperm concentration (r = 0.460, P &lt; 0.001) and nonsignificant correlation with age (r = 0.021, P = 0.940), sperm motility percentage (r = 0.142, P = 0.615) and semen volume (r = 0.035, P = 0.087). Conclusion: Seminal plasma laminin is derived mostly from prostatic and testicular portions and minimally from the seminal vesicle and vas deferens. Estimating seminal laminin alone is not conclusive in diagnosing different cases of male infertility. (Asian J Androl 2007 Jan; 9: 63-67

    Range expansion with mutation and selection: dynamical phase transition in a two-species Eden model

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    The colonization of unoccupied territory by invading species, known as range expansion, is a spatially heterogeneous non-equilibrium growth process. We introduce a two-species Eden growth model to analyze the interplay between uni-directional (irreversible) mutations and selection at the expanding front. While the evolutionary dynamics leads to coalescence of both wild-type and mutant clusters, the non-homogeneous advance of the colony results in a rough front. We show that roughening and domain dynamics are strongly coupled, resulting in qualitatively altered bulk and front properties. For beneficial mutations the front is quickly taken over by mutants and growth proceeds Eden-like. In contrast, if mutants grow slower than wild-types, there is an antagonism between selection pressure against mutants and growth by the merging of mutant domains with an ensuing absorbing state phase transition to an all-mutant front. We find that surface roughening has a marked effect on the critical properties of the absorbing state phase transition. While reference models, which keep the expanding front flat, exhibit directed percolation critical behavior, the exponents of the two-species Eden model strongly deviate from it. In turn, the mutation-selection process induces an increased surface roughness with exponents distinct from that of the classical Eden model

    Crossover effects in a discrete deposition model with Kardar-Parisi-Zhang scaling

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    We simulated a growth model in 1+1 dimensions in which particles are aggregated according to the rules of ballistic deposition with probability p or according to the rules of random deposition with surface relaxation (Family model) with probability 1-p. For any p>0, this system is in the Kardar-Parisi-Zhang (KPZ) universality class, but it presents a slow crossover from the Edwards-Wilkinson class (EW) for small p. From the scaling of the growth velocity, the parameter p is connected to the coefficient of the nonlinear term of the KPZ equation, lambda, giving lambda ~ p^gamma, with gamma = 2.1 +- 0.2. Our numerical results confirm the interface width scaling in the growth regime as W ~ lambda^beta t^beta, and the scaling of the saturation time as tau ~ lambda^(-1) L^z, with the expected exponents beta =1/3 and z=3/2 and strong corrections to scaling for small lambda. This picture is consistent with a crossover time from EW to KPZ growth in the form t_c ~ lambda^(-4) ~ p^(-8), in agreement with scaling theories and renormalization group analysis. Some consequences of the slow crossover in this problem are discussed and may help investigations of more complex models.Comment: 16 pages, 7 figures; to appear in Phys. Rev.

    Slot Suction Requirement for Two-Dimensional Griffith Diffusers

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