3,789 research outputs found

    Alterations in neuronal morphology and synaptophysin expression in the rat brain as a result of changes in dietary n-6: n-3 fatty acid ratios

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    Background: Polyunsaturated fatty acids (PUFA) play important roles in brain fatty acid composition and behavior through their effects on neuronal properties and gene expression. The hippocampus plays an important role in the formation of memory, especially spatial memory and navigation. This study was conducted to examine the effects of PUFA and specifically different dietary n-6: n-3 fatty acid ratios (FAR) on the number and size of hippocampal neurons and the expression of synaptophysin protein in the hippocampus of rats. Methods: Forty 3-week old male Sprague–Dawley rats were allotted into 4 groups. The animals received experimental diets with different n-6: n-3 FAR of either 65:1, 26.5:1, 22:1 or 4.5:1 for 14 weeks. Results: The results showed that a lowering dietary n-6: n-3 FAR supplementation can increase the number and size of neurons. Moreover, lowering the dietary n-6: n-3 FAR led to an increase in the expression of the pre-synaptic protein synaptophysin in the CA1 hippocampal subregion of the rat brain. Conclusions: These findings support the notion that decreasing the dietary n-6: n-3 FAR will lead to an intensified hippocampal synaptophysin expression and increased neuron size and proliferation in the rat brain

    Optimization of cyclodextrin glycosyltransferase production by response surface methodology approach.

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    The aim of the study was to optimized cyclodextrin glycosyltransferase (CGTase) production using local isolated strain MK6 which was identified as Bacillus sp. Optimum activity obtained at temperature of 70 °C and the enzyme shows a wide range of pH stability ranging from 4-10 when stored at 4 °C for 24 h and temperature stability ranging from 30-80 °C at 1 h incubation period. The CGTase activity was even maintained at 0.4 U mL-1 at 90 °C for 40 min incubation. Prior to optimization of CGTase production, selection for the best carbon source through detection using modified phenolphthalein method containing different types of starch were performed. Sago starch gave significant result and was used for further optimization using statistical analysis namely Response Surface Methodology (RSM) approach. The optimal calculated values were 3.34% sago starch, initial pH of 10.15 and agitation speed of 187 rpm; with predicted activity of 2.07 U mL-1 of CGTase. These predicted optimal parameters were confirmed in the laboratory and the final CGTase activity obtained was very close to the predicted value of 2.56 U mL-1

    Atrial fibrillation and electrophysiology in transgenic mice with cardiac-restricted overexpression of FKBP12

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    Cardiomyocyte-restricted overexpression of FK506-binding protein 12 transgenic (αMyHC-FKBP12) mice develop spontaneous atrial fibrillation (AF). The aim of the present study is to explore the mechanisms underlying the occurrence of AF in αMyHC-FKBP12 mice. Spontaneous AF was documented by telemetry in vivo and Langendorff-perfused hearts of αMyHC-FKBP12 and littermate control mice in vitro. Atrial conduction velocity was evaluated by optical mapping. The patch-clamp technique was applied to determine the potentially altered electrophysiology in atrial myocytes. Channel protein expression levels were evaluated by Western blot analyses. Spontaneous AF was recorded in four of seven αMyHC-FKBP12 mice but in none of eight nontransgenic (NTG) controls. Atrial conduction velocity was significantly reduced in αMyHC-FKBP12 hearts compared with NTG hearts. Interestingly, the mean action potential duration at 50% but not 90% was significantly prolonged in αMyHC-FKBP12 atrial myocytes compared with their NTG counterparts. Consistent with decreased conduction velocity, average peak Na+ current ( INa) density was dramatically reduced and the INa inactivation curve was shifted by approximately +7 mV in αMyHC-FKBP12 atrial myocytes, whereas the activation and recovery curves were unaltered. The Nav1.5 expression level was significantly reduced in αMyHC-FKBP12 atria. Furthermore, we found increases in atrial Cav1.2 protein levels and peak L-type Ca2+ current density and increased levels of fibrosis in αMyHC-FKBP12 atria. In summary, cardiomyocyte-restricted overexpression of FKBP12 reduces the atrial Nav1.5 expression level and mean peak INa, which is associated with increased peak L-type Ca2+ current and interstitial fibrosis in atria. The combined electrophysiological and structural changes facilitated the development of local conduction block and altered action potential duration and spontaneous AF. NEW & NOTEWORTHY This study addresses a long-standing riddle regarding the role of FK506-binding protein 12 in cardiac physiology. The work provides further evidence that FK506-binding protein 12 is a critical component for regulating voltage-gated sodium current and in so doing has an important role in arrhythmogenic physiology, such as atrial fibrillation

    Numerical Investigation on Serpentine Flow Field and Rhombus Electrolyte Compartment of Vanadium Redox Flow Battery (V-RFB)

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    Selection of suitable material, fitting for prototype design and pumping rates are three affecting element for cost effectiveness and improve performance of vanadium cell prototype investigation. Therefore, three-dimensional numerical model isothermal computational fluid dynamics (CFD) model of vanadium redox flow battery (V-RFB) is studied. In this work, V-RFB with different electrolyte compartments is proposed and the effect of serpentine flow field is investigated. The performance of two V-RFBs with diamond and square electrolyte compartment is numerically tested. This work has been performed to optimize flow rate, electrolyte compartment design, avoid stagnant fluid and flow field application in VRFB. For the simulation, the flow was assumed to be incompressible, isothermal, steady state flow, laminar and Newtonian flow. Results show that the application of flow field and Rhombus type electrolyte compartment can facilitate the distribution of electrolyte in the unit cell uniformity and avoid stagnant in the tank. Simulation results indicate the diamond shape and serpentine flow field at optimal flow rate show the most suitable for V-RFBs than square shape

    Exploring rural secondary school students' attitude toward the Malayan tapir through salient beliefs

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    Environmental education programmes in Malaysia have been successful in increasing students' knowledge but not so in changing attitudes. To design educational programmes that changes attitudes, we need to understand the underlying determinant of attitude. The purpose of the study was to explore and elicit rural secondary school students' attitudes towards the Malayan tapir through their salient beliefs. Focusing on the cognitive and affective components of the attitude model, eighty-one secondary school students were asked to elucidate what they knew about the Malayan tapir through pictorial stimulation in focus group discussion. Students were observed to be intrigued by the physical characteristics of the Malayan tapir but knew little about its ecological function, natural habitat and threats while displaying positive and negative emotions in reaction to the pictures. Future research implications include the designing of an environmental education programme based on the observations of this study and measuring the effectiveness of the programme in influencing behaviour

    Comparative Phytochemical Screening And Antioxidant Activities of Calligonum Comosum And Calligonum Crjnitum

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    Medicinal plants are vital source of present day prescription and the majority of the recommended modern medications contain their subsidiaries. Calligonum comosum and Calligonum crinitum are perennial shrub plants growing in the United Arab Emirates, and are being utilized as a part of traditional medicinal system of UAE. The aims of proposed study were to evaluate and compare the phytochemical and antioxidant properties of these two plants. The extraction and fractionation were conducted by using petroleum ether, chloroform, ethyl acetate, acetone and methanol. The extracts were tested for their antioxidant activity. Phytochemical studies with total phenolics and flavonoid contents were analyzed by following standard methods. Along with this, proximate analysis with micro and macro elements were also estimated. In vitro antioxidant analysis were done by different methods. The results exhibited a positive linear correlation between these phytochemicals such as saponins, flavonoids, tannins, and terpenes and the free radical scavenging activities. Our results confirm that the extracts have potential antioxidants and this legitimizes their use in folkloric medicine. Hence, scientific validation of traditional knowledge can be accomplished in a preparatory level

    Strain-dependent host transcriptional responses to toxoplasma infection are largely conserved in mammalian and avian hosts

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    Toxoplasma gondii has a remarkable ability to infect an enormous variety of mammalian and avian species. Given this, it is surprising that three strains (Types I/II/III) account for the majority of isolates from Europe/North America. The selective pressures that have driven the emergence of these particular strains, however, remain enigmatic. We hypothesized that strain selection might be partially driven by adaptation of strains for mammalian versus avian hosts. To test this, we examine in vitro, strain-dependent host responses in fibroblasts of a representative avian host, the chicken (Gallus gallus). Using gene expression profiling of infected chicken embryonic fibroblasts and pathway analysis to assess host response, we show here that chicken cells respond with distinct transcriptional profiles upon infection with Type II versus III strains that are reminiscent of profiles observed in mammalian cells. To identify the parasite drivers of these differences, chicken fibroblasts were infected with individual F1 progeny of a Type II x III cross and host gene expression was assessed for each by microarray. QTL mapping of transcriptional differences suggested, and deletion strains confirmed, that, as in mammalian cells, the polymorphic rhoptry kinase ROP16 is the major driver of strain-specific responses. We originally hypothesized that comparing avian versus mammalian host response might reveal an inversion in parasite strain-dependent phenotypes; specifically, for polymorphic effectors like ROP16, we hypothesized that the allele with most activity in mammalian cells might be less active in avian cells. Instead, we found that activity of ROP16 alleles appears to be conserved across host species; moreover, additional parasite loci that were previously mapped for strain-specific effects on mammalian response showed similar strain-specific effects in chicken cells. These results indicate that if different hosts select for different parasite genotypes, the selection operates downstream of the signaling occurring during the beginning of the host's immune response. © 2011 Ong et al

    A study of incremental sheet forming by using water jet

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    In this work, a variant of the incremental sheet forming (ISF) process, namely the incremental sheet forming by using water jet (ISF-WJ), was studied. In the investigation, an ISF-WJ prototype machine was designed and developed. Different design concepts of the water jet nozzle were proposed and evaluated to achieve the maximum forming pressure by performing computational fluid dynamic (CFD) simulations. Based on the forming pressure distribution modeled by CFD simulations, finite element (FE) models were developed to study the sheet deformation behavior under the ISF-WJ process condition. Based on the understanding gained from the numerical study, experiments were conducted to validate the ISF-WJ process and the developed prototype machine. The results suggest that ISF-WJ is a feasible process to achieve improved surface finish of thin sheet parts. In addition, this study has found that water jet pressure plays an important role in preventing sheet wrinkling and obtaining an accurate geometry of formed parts

    Linking Halal Food Certification and Business Performance

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    Purpose: The purpose of this paper is to explore the relationship between Halal food certification (HFC) and business performance. This study argues that Halal food certificate implementation positively influences business performance. Design/methodology/approach: A total of 210 Halal certified food manufacturing companies in Malaysia participated in the study. Data were gathered through a structured questionnaire and were analysed using partial least squares structural equation modelling technique. Findings: The study proved that HFC has a positive relationship with operational performance. Additionally, operational performance mediates the relationship between HFC and financial performance. Altogether, this signifies that Halal food certificate implementation positively influences business performance. Practical implications: By linking HFC and business performance, managers may be aware of the significant role of HFC in influencing operational and financial performance. It would entice more food companies to become Halal certified that opens up an opportunity to a lucrative Halal food industry. It also empirically justifies that a religion-based food certification has the ability to influence business performance, consistent with other established food standards such as ISO 22000 or HACCP. Originality/value: Although numerous studies have concentrated on well-established food certifications, the expanding Muslim population, rising demand for Halal food, and lucrative Halal food market have raised the attention on HFC research among academicians and practitioners. This research is able to highlight the importance of implementing HFC among food companies as it could potentially lead to superior business outcomes

    Measurement of the cross-section and charge asymmetry of WW bosons produced in proton-proton collisions at s=8\sqrt{s}=8 TeV with the ATLAS detector

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    This paper presents measurements of the W+μ+νW^+ \rightarrow \mu^+\nu and WμνW^- \rightarrow \mu^-\nu cross-sections and the associated charge asymmetry as a function of the absolute pseudorapidity of the decay muon. The data were collected in proton--proton collisions at a centre-of-mass energy of 8 TeV with the ATLAS experiment at the LHC and correspond to a total integrated luminosity of 20.2~\mbox{fb^{-1}}. The precision of the cross-section measurements varies between 0.8% to 1.5% as a function of the pseudorapidity, excluding the 1.9% uncertainty on the integrated luminosity. The charge asymmetry is measured with an uncertainty between 0.002 and 0.003. The results are compared with predictions based on next-to-next-to-leading-order calculations with various parton distribution functions and have the sensitivity to discriminate between them.Comment: 38 pages in total, author list starting page 22, 5 figures, 4 tables, submitted to EPJC. All figures including auxiliary figures are available at https://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/STDM-2017-13
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