13,630 research outputs found

    The effect of interaction between Lipoprotein Lipase and ApoVLDL-II genes on fat and serum biochemical levels

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    Body weight, abdominal fat weight and serum biochemical levels were determined from lean and fat chicken breeds at 12 weeks of age. Single nucleotide polymorphism (SNP) in apoVLDL-II and lipoprotein lipase genes was screened by PCR-SSCP and detected by direct sequencing. Lipoprotein lipase gene frequency was found to be significantly different (P < 0.01) in lean chicken whereas it was non-significantly different in fat chicken. SNP in apoVLDL-II and lipoprotein lipase genes significantly (P< 0.05) affected body weight and fat weight. Similarly their interaction significantly (P < 0.05) affected body weight and fat weight. However, no significant difference was observed in the percentage of abdominal fat. SNP in apoVLDL-II and lipoprotein lipase genes significantly (P < 0.05) affected total cholesterol and high density lipoprotein. More likely, the interaction of apoVLDL-II and lipoprotein lipase significantly affect total cholesterol, triglyceride, high density lipoprotein, very low density lipoprotein and low density lipoprotein

    In-situ monitoring techniques for membrane fouling and local filtration characteristics in hollow fiber membrane processes: A critical review

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    © 2017 Elsevier B.V. Membrane fouling is the most serious challenge in the hollow fiber microfiltration (MF) and ultrafiltration (UF) processes. A number of in-situ monitoring techniques including optical and non-optical probes have been developed so that membrane fouling is better understood and controlled. This will help advance the membrane technology. In addition, the local filtration hydrodynamics wield a great influence on the membrane fouling formation and system operation stability. State-of-the-art in-situ monitoring techniques for membrane fouling and local filtration characteristics in hollow fiber MF/UF processes are critically reviewed. The principles and applications of these techniques are addressed in order to assess their strengths. This study demonstrated that the real-time observation techniques mainly focus on idealized laboratory apparatus and little on commercial membrane modules. Consequently, more attention should be paid to the development of simple and effective methods or integrated detecting technology so as to satisfy the real status of hollow fiber filtration processes and the optimization of membrane module. On the basis of this review, future analyses considering practical requirements are suggested as R&D priorities

    A new sponge tray bioreactor in primary treated sewage effluent treatment

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    The new attached growth sponge tray bioreactor (STB) was evaluated at different operating conditions for removing organics and nutrients from primary treated sewage effluent. This STB was also assessed when using as a pre-treatment prior to micro-filtration (MF) for reducing membrane fouling. At a short hydraulic retention time (HRT) of 40min, the STB could remove up to 92% of DOC and 40-56% of T-N and T-P at an organic loading rate (OLR) of 2.4kg COD/m3 spongeday. This OLR is the best for the STB as compared to the OLRs of 0.6, 1.2 and 3.6kg COD/m3 spongeday. At 28mL/min of flow velocity (FV), STB achieved the highest efficiencies with 92% of DOC, 87.4% of T-P, and 54.8% of T-N removal. Finally, at the optimal OLR and FV, the STB could remove almost 90% of organic and nutrient, significantly reduce membrane fouling with HRT of only 120min. © 2010 Elsevier Ltd

    Anodic-oxide-induced interdiffusion in quantum wells structure

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    Enhancement of interdiffusion in GaAs/AlGaAs quantum wells (QWs) due to anodic oxides was studied. Photoluminescence and diffused QW modeling were used to understand the effects of intermixing on the QW structure. The activation energy is similar to those obtained from SiO 2 cap annealed quantum well structures.published_or_final_versio

    Dynamic membrane-assisted fermentation of food wastes for enhancing lactic acid production

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    © 2017 Elsevier Ltd A dynamic membrane (DM) module was inserted into a fermentation reactor to separate soluble products from the fermented mixture to increase lactic acid (LA) production from food wastes under acidogenic conditions (uncontrolled pH, pH 4 and 5). With a high total suspended solid content (20–40 g/L) in the fermenter, a stable DM could be maintained through regular backwashing. By effectively intercepting suspended solids and lactic acid bacteria (LAB), the fermenter was able to increase microbial activity and largely promote LA yield. Hydrolysis and acidogenesis rates increased with pH, and the highest LA yield (as high as 0.57 g/g-TS) was obtained at pH 4. The microbial community analysis showed that the relative abundance of Lactobacillus increased to 96.4% at pH 4, but decreased to 43.3% at pH 5. In addition, the DM could be easily recovered by intercepting larger particles in less than 2 h after each cycle of periodic backwashing

    Lipid consumption in coral larvae differs among sites: a consideration of environmental history in a global ocean change scenario

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    The success of early life-history stages is an environmentally sensitive bottleneck for many marine invertebrates. Responses of larvae to environmental stress may vary due to differences in maternal investment of energy stores and acclimatization/adaptation of a population to local environmental conditions. In this study, we compared two populations from sites with different environmental regimes (Moorea and Taiwan). We assessed the responses of Pocillopora damicornis larvae to two future co-occurring environmental stressors: elevated temperature and ocean acidification. Larvae from Taiwan were more sensitive to temperature, producing fewer energy-storage lipids under high temperature. In general, planulae in Moorea and Taiwan responded similarly to pCO(2). Additionally, corals in the study sites with different environments produced larvae with different initial traits, which may have shaped the different physiological responses observed. Notably, under ambient conditions, planulae in Taiwan increased their stores of wax ester and triacylglycerol in general over the first 24 h of their dispersal, whereas planulae from Moorea consumed energy-storage lipids in all cases. Comparisons of physiological responses of P. damicornis larvae to conditions of ocean acidification and warming between sites across the species\u27 biogeographic range illuminates the variety of physiological responses maintained within P. damicornis, which may enhance the overall persistence of this species in the light of global climate change

    A belief propagation approach for distributed user association in heterogeneous networks

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    © 2014 IEEE. In heterogeneous networks (HetNets), the load between macro-cell base stations (MBSs) and small-cell BSs (SBSs) is imbalanced due to transmit power disparities and ad-hoc deployment of SBSs. This significantly impacts the system performance and user experience. Associating more users to the SBSs is an effective way to solve this problem. In this paper, we formulate the user-BS association problem as a distributed optimization problem with proportional fairness as the objective. Specifically, we propose a novel distribute algorithm based on the belief propagation (BP) method to solve the user-BS association problem via iteratively message passing between the users and BSs. Also, we develop an approximation calculation in the BP method to reduce the computational complexity and transmission overhead of message passing. Simulation results show that the proposed algorithm well approaches the optimal system performance (by exhausting search) with low complexity and fast convergence

    Defunct brain stem cardiovascular regulation underlies cardiovascular collapse associated with methamphetamine intoxication

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    <p>Abstract</p> <p>Background</p> <p>Intoxication from the psychostimulant methamphetamine (METH) because of cardiovascular collapse is a common cause of death within the abuse population. For obvious reasons, the heart has been taken as the primary target for this METH-induced toxicity. The demonstration that failure of brain stem cardiovascular regulation, rather than the heart, holds the key to cardiovascular collapse induced by the pesticide mevinphos implicates another potential underlying mechanism. The present study evaluated the hypothesis that METH effects acute cardiovascular depression by dampening the functional integrity of baroreflex via an action on brain stem nuclei that are associated with this homeostatic mechanism.</p> <p>Methods</p> <p>The distribution of METH in brain and heart on intravenous administration in male Sprague-Dawley rats, and the resultant changes in arterial pressure (AP), heart rate (HR) and indices for baroreflex-mediated sympathetic vasomotor tone and cardiac responses were evaluated, alongside survival rate and time.</p> <p>Results</p> <p>Intravenous administration of METH (12 or 24 mg/kg) resulted in a time-dependent and dose-dependent distribution of the psychostimulant in brain and heart. <b/>The distribution of METH to neural substrates associated with brain stem cardiovascular regulation was significantly larger than brain targets for its neurological and psychological effects; the concentration of METH in cardiac tissues was the lowest among all tissues studied. In animals that succumbed to METH, the baroreflex-mediated sympathetic vasomotor tone and cardiac response were defunct, concomitant with cessation of AP and HR. On the other hand, although depressed, those two indices in animals that survived were maintained, alongside sustainable AP and HR. Linear regression analysis further revealed that the degree of dampening of brain stem cardiovascular regulation was positively and significantly correlated with the concentration of METH in key neural substrate involved in this homeostatic mechanism.</p> <p>Conclusions</p> <p>We conclude that on intravenous administration, METH exhibits a preferential distribution to brain stem nuclei that are associated with cardiovascular regulation. We further found that the concentration of METH in those brain stem sites dictates the extent that baroreflex-mediated sympathetic vasomotor tone and cardiac responses are compromised, which in turn determines survival or fatality because of cardiovascular collapse.</p

    Performance evaluation of powdered activated carbon for removing 28 types of antibiotics from water

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    © 2016 Elsevier Ltd. Currently, the occurrence and fate of antibiotics in the aquatic environment has become a very serious problem in that they can potentially and irreversibly damage the ecosystem and human health. For this reason, interest has increased in developing strategies to remove antibiotics from water. This study evaluated the performance of powdered activated carbon (PAC) in removing from water 6 representative groups of 28 antibiotics, namely Tetracyclines (TCs), Macrolides (MCs), Chloramphenicols (CPs), Penicillins (PNs), Sulfonamides (SAs) and Quinolones (QNs). Results indicate that PAC demonstrated superior adsorption capacity for all selected antibiotics. The removal efficiency was up to 99.9% in deionized water and 99.6% in surface water at the optimum conditions with PAC dosage of 20 mg/L and contact time of 120 min. According to the Freundlich model's adsorption isotherm, the values of n varied among these antibiotics and most were less than 1, suggesting that the adsorption of antibiotics onto PAC was nonlinear. Adsorption of antibiotics followed well the pseudo-second-order kinetic model (R2 = 0.99). Analysis using the Weber-Morris model revealed that the intra-particle diffusion was not the only rate-controlling step. Overall, the findings in this study confirm that PAC is a feasible and viable option for removing antibiotics from water in terms of water quality improvement and urgent antibiotics pollution control. Further research is essential on the following subjects: (i) removing more types of antibiotics by PAC; (ii) the adsorption process; and (iii) the mechanism of the competitive adsorption existing between natural organic matters (NOMs) and antibiotics

    New proposed conceptual mathematical models for biomass viability and membrane fouling of membrane bioreactor

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    The production and accumulation of soluble microbial products (SMP), extracellular polymeric substances (EPS) and colloidal inert compounds within a membrane bioreactor (MBR) may greatly affect the biomass viability and subsequently the permeability of the membrane. This paper aims at presenting new mathematical models of biomass viability and membrane fouling that has been conceptually developed through establishing links between these biomass parameters and operating parameters of the MBR. The proposed models can be used to predict the biomass viability and membrane fouling at any state of operation of MBR. Meanwhile, easily measurable parameters of the proposed model can also serve to estimate SMP/EPS concentration in the supernatant of MBR without the tedious and expensive measurement. © 2013 Elsevier Ltd
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