54 research outputs found

    Co-gasification of coal and empty fruit bunch in an entrained flow gasifier : A process simulation study

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    Co-gasification of coal and biomass is a proven method to improve gasification performance and a platform towards being independent of fossil fuel in power generation. Thus, this research was conducted to assess the feasibility of coal and EFB as fuels in co-gasification using Aspen HYSYS. A sequential model of an EFG was developed to predict the syngas composition and the optimum operating condition of the gasifier. The process was modelled with a set of five reactors to simulate various reaction zones of EFG in accordance with its hydrodynamics. The model considers devolatilization, char and volatile combustion, char gasification and water-gas shift reactions. The model prediction has exhibited excellent agreement with the experimental results. Three parameters of BR, Top and S/F were considered to account for their impacts on syngas composition in the process. The CE, CGE, PE and HHV were adopted as the indicators of process performance. The optimal values of BR, Top and S/F were 50%, 950°C and 0.75, respectively. While the value of CE reached above 90% and the maximum value of CGE, PE and HHV was obtained. This finding should be helpful in designing, operating, optimizing and controlling any co-gasification process especially in the entrained flow system

    Sensitivity analysis of leaching process on rare earth elements by using metsim software

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    Leaching is part of the hydrometallurgical treatment in the separation of rare earth elements (REEs). The increase of demand for REEs in the world but its limited supply caused by the separation process that has negative environmental impact, as well as high costs of laboratory work, the alternative method to study on the extraction of these resources are urgently needed. This can be done through simulation study that eliminates the number of experiment that needs to be carried out. In this work, a sensitivity analysis of the leaching process for light rare earth elements (LREEs); Lanthanum (La) and Neodymium (Nd) from monazite concentrate was carried out by employing a software called METSIM which is able to model metallurgical processes. METSIM software is also able to calculate mass and heat balance of complicated hydrometallurgy processes and furthermore, its function has been expanded to involved chemical reactions, process control and equipment sizing. The simulation of the digestion and the leaching process was run and compared with experimental work from the literature, which aimed to optimize the leaching process. Leaching is an extraction process of a substance from a solid material that is dissolved in a liquid. In this study, the leaching process is modelled as a two-steps process, in which the first step is the digestion process, followed by the actual leaching process. The monazite concentrate is made strong bonds as REEs oxide, therefore, they are not soluble in water before leaching process. For the digestion process, the monazite concentrate was mixed with sulfuric acid (H2SO4) in the digestion reactor. The precipitates which contain leachate was then mixed with deionised water in the leaching reactor to increase the solubility of La and Nd. The reaction equations for the digestion reactor are as shown in Equations (1) and (2), while for the leaching reactor are shown by Equations (3) and (4) as follows

    Osteoarthritis-Like Changes in Bardet–Biedl Syndrome Mutant Ciliopathy Mice (Bbs1M390R/M390R): Evidence for a Role of Primary Cilia in Cartilage Homeostasis and Regulation of Inflammation

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    Osteoarthritis (OA) is a debilitating inflammation related disease characterized by joint pain and effusion, loss of mobility, and deformity that may result in functional joint failure and significant impact on quality of life. Once thought of as a simple “wear and tear” disease, it is now widely recognized that OA has a considerable metabolic component and is related to chronic inflammation. Defects associated with primary cilia have been shown to be cause OA-like changes in Bardet–Biedl mice. We examined the role of dysfunctional primary cilia in OA in mice through the regulation of the previously identified degradative and pro-inflammatory molecular pathways common to OA. We observed an increase in the presence of pro-inflammatory markers TGFβ-1 and HTRA1 as well as cartilage destructive protease MMP-13 but a decrease in DDR-2. We observed a morphological difference in cartilage thickness in Bbs1M390R/M390R mice compared to wild type (WT). We did not observe any difference in OARSI or Mankin scores between WT and Bbs1M390R/M390R mice. Primary cilia appear to be involved in the upregulation of biomarkers, including pro-inflammatory markers common to OA

    Rheotaxis in Larval Zebrafish Is Mediated by Lateral Line Mechanosensory Hair Cells

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    The lateral line sensory system, found in fish and amphibians, is used in prey detection, predator avoidance and schooling behavior. This system includes cell clusters, called superficial neuromasts, located on the surface of head and trunk of developing larvae. Mechanosensory hair cells in the center of each neuromast respond to disturbances in the water and convey information to the brain via the lateral line ganglia. The convenient location of mechanosensory hair cells on the body surface has made the lateral line a valuable system in which to study hair cell damage and regeneration. One way to measure hair cell survival and recovery is to assay behaviors that depend on their function. We built a system in which orientation against constant water flow, positive rheotaxis, can be quantitatively assessed. We found that zebrafish larvae perform positive rheotaxis and that, similar to adult fish, larvae use both visual and lateral line input to perform this behavior. Disruption or damage of hair cells in the absence of vision leads to a marked decrease in rheotaxis that recovers upon hair cell repair or regeneration

    Adherence issues related to sublingual immunotherapy as perceived by allergists

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    Objectives: Sublingual immunotherapy (SLIT) is a viable alternative to subcutaneous immunotherapy to treat allergic rhinitis and asthma, and is widely used in clinical practice in many European countries. The clinical efficacy of SLIT has been established in a number of clinical trials and meta-analyses. However, because SLIT is self-administered by patients without medical supervision, the degree of patient adherence with treatment is still a concern. The objective of this study was to evaluate the perception by allergists of issues related to SLIT adherence. Methods: We performed a questionnaire-based survey of 296 Italian allergists, based on the adherence issues known from previous studies. The perception of importance of each item was assessed by a VAS scale ranging from 0 to 10. Results: Patient perception of clinical efficacy was considered the most important factor (ranked 1 by 54% of allergists), followed by the possibility of reimbursement (ranked 1 by 34%), and by the absence of side effects (ranked 1 by 21%). Patient education, regular follow-up, and ease of use of SLIT were ranked first by less than 20% of allergists. Conclusion: These findings indicate that clinical efficacy, cost, and side effects are perceived as the major issues influencing patient adherence to SLIT, and that further improvement of adherence is likely to be achieved by improving the patient information provided by prescribers. © 2010 Scurati et al, publisher and licensee Dove Medical Press Ltd

    Dcc Regulates Asymmetric Outgrowth of Forebrain Neurons in Zebrafish

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    The guidance receptor DCC (deleted in colorectal cancer) ortholog UNC-40 regulates neuronal asymmetry development in Caenorhabditis elegans, but it is not known whether DCC plays a role in the specification of neuronal polarity in vertebrates. To examine the roles of DCC in neuronal asymmetry regulation in vertebrates, we studied zebrafish anterior dorsal telencephalon (ADt) neuronal axons. We generated transgenic zebrafish animals expressing the photo-convertible fluorescent protein Kaede in ADt neurons and then photo-converted Kaede to label specifically the ADt neuron axons. We found that ADt axons normally project ventrally. Knock down of Dcc function by injecting antisense morpholino oligonucleotides caused the ADt neurons to project axons dorsally. To examine the axon projection pattern of individual ADt neurons, we labeled single ADt neurons using a forebrain-specific promoter to drive fluorescent protein expression. We found that individual ADt neurons projected axons dorsally or formed multiple processes after morpholino knock down of Dcc function. We further found that knock down of the Dcc ligand, Netrin1, also caused ADt neurons to project axons dorsally. Knockdown of Neogenin1, a guidance receptor closely related to Dcc, enhanced the formation of aberrant dorsal axons in embryos injected with Dcc morpholino. These experiments provide the first evidence that Dcc regulates polarized axon initiation and asymmetric outgrowth of forebrain neurons in vertebrates

    Dynamic assembly of ribbon synapses and circuit maintenance in a vertebrate sensory system

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    Ribbon synapses transmit information in sensory systems, but their development is not well understood. To test the hypothesis that ribbon assembly stabilizes nascent synapses, we performed simultaneous time-lapse imaging of fluorescently-tagged ribbons in retinal cone bipolar cells (BCs) and postsynaptic densities (PSD95-FP) of retinal ganglion cells (RGCs). Ribbons and PSD95-FP clusters were more stable when these components colocalized at synapses. However, synapse density on ON-alpha RGCs was unchanged in mice lacking ribbons (ribeye knockout). Wildtype BCs make both ribbon-containing and ribbon-free synapses with these GCs even at maturity. Ribbon assembly and cone BC-RGC synapse maintenance are thus regulated independently. Despite the absence of synaptic ribbons, RGCs continued to respond robustly to light stimuli, although quantitative examination of the responses revealed reduced frequency and contrast sensitivity

    Commercial genetic testing in mainland China: Social, financial and ethical issues

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    This paper provides an empirical account of commercial genetic predisposition testing in mainland China, based on interviews with company mangers, regulators and clients, and literature research during fieldwork in mainland China from July to September 2006. This research demonstrates that the commercialization of genetic testing and the lack of adequate regulation have created an environment in which dubious advertising practices and misleading and unprofessional medical advice are commonplace. The consequences of these ethically problematic activities for the users of predictive tests are, as yet, unknown. The paper concludes with a bioethical and social science perspective on the social and ethical issues raised by the dissemination and utilization of genetic testing in mainland China
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