777 research outputs found

    Miniaturized Microstrip Filter Design Using Active Learning Method

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    Relating coupling and external quality factor of a filter to the physical parameters of the structure which is the final step of any filter design is usually complicated due to geometrical complexities of the filter, or in the case of microstrip resonators due to the lack of the exact solution for the field distribution. Therefore, common approach is using time consuming full wave simulations. In this paper active learning method (ALM) which is a fuzzy-based modeling technique developed by a procedure algorithmically mimics the information-handling process of the human brain, is proposed to overcome this drawback. Modeling steps of an unknown function using ALM will be described using an illustrative example. Afterwards, the modeling approach will be implemented to model coupling factor between two coupled spiral resonators (SRs) for two different coupling structures and external quality factor of the same resonator. Accuracy of the extracted surfaces is validated using two different criteria. Using the extracted surfaces; a four pole chebychev bandpass filter was designed and fabricated. Good agreement between the measured response and simulation validated the accuracy of the extracted surfaces again. Comparing the fabricated SR filter with a square open loop resonator (SOLR) one demonstrates more than 70% of filter area reduction

    Dynamics of a vapour bubble near a thin elastic plate

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    Numerical and experimental results show that during the collapse phase of a vapor bubble near a rigid boundary, in the absence of strong buoyancy forces, a liquid micro jet is developed on the side of the bubble far from the rigid surface and directed towards it. Numerical and experimental results also show that, in the case of a bubble near a free surface, during the collapse phase of the bubble and in the absence of strong buoyancy forces, the vapor bubble is repelled by the free surface. In this case a liquid micro jet is developed on the closest side of the bubble to the free surface and is directed away from it. The dynamic behavior of a vapor bubble near a free surface leads to the idea that a vapor bubble during its growth and collapse phases near a deformable diaphragm may have a behavior similar to its behavior near a free surface. In this paper dynamics of a vapor bubble during its growth and collapse phases near a thin elastic plate is investigated. It has been shown that the growth and collapse of a vapor bubble generated due to a high local energy input causes considerable deformation on the nearby thin elastic plate. Different thin elastic plates with different thicknesses and different flexural rigidities are assumed and the dynamic behavior of a vapor bubble near each of these plates is investigated. Results show that during the growth and collapse of a vapor bubble near a thin elastic plate with a proper thickness and flexural rigidity, in the absence of strong buoyancy forces, a liquid micro jet may develop on the closest side of the bubble to the thin elastic plate and directed away from it.http://deepblue.lib.umich.edu/bitstream/2027.42/84307/1/CAV2009-final132.pd

    Permeability Prediction from Mercury Injection Capillary Pressure: An Example from the Perth Basin, Western Australia

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    For shale gas reservoirs, permeability is one of the most important—and difficult—parameters to determine. Typical shale matrix permeabilities are in the range of 10 microdarcy–100 nanodarcy, and are heavily dependent on the presence of natural fractures for gas transmissibility. Permeability is a parameter used to measure the ability of a rock to convey fluid. It is directly related to porosity and depends on the pore geometry features, such as tortuosity, pore shape and pore connectivity. Consequently, rocks with similar porosity can exhibit different permeability. Generally, permeability is measured in laboratories using core plugs. In some cases, however, it is difficult to obtain suitable core plugs. In these instances, other approaches can be used to predict permeability, which are chiefly based on mathematical and theoretical models. The approach followed in this peer-reviewed paper is to correlate permeability with capillary pressure data from mercury injection measurements. The theoretical and empirical equations, introduced in the literature for various conventional and unconventional reservoir rocks, have been used to predict permeability. Estimated gas shale permeabilities are then compared with results from transient and steady state methods on small pieces of rocks embedded in a resin disk. The study also attempts to establish a suitable equation that is applicable to gas shale formations and to investigating the relationship between permeability and porosity

    Implication of complex vertebral malformation and deficiency of uridine monophosphate synthase on molecular-based testing in the Iranian Holstein bulls population

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    The aim of this study was to identify the deficiency of uridine monophosphate synthase (DUMPS) and the complex vertebral malformation (CVM) in Iranian Holstein bulls. A total of 144 blood samples were prepared of Holstein bulls in Abbas Abad Animal Breeding Center and Ferdowsi University of Mashhad's Dairy Farm in Khorasan state of Iran. Genomic PCR-RFLP protocol was performed to amplify the polymorphic region of the bovine uridine monophosphate synthase UMPS gene. Also, genomic PCR-SSCP method was performed for CVM to amplify the polymorphic region of the bovine solutecarrier family 35 member 3 (SLC35A3) genes. The results of this study demonstrated that there was no carrier of DUMPS and CVM in Iranian bulls in these centers

    Identification and Evaluation of Unconventional Hydrocarbon Reserves: Examples from Zagros and Central Iran Basins

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    It is notable that over the past decade, proven reserves of natural gas have dramatically increased as higher prices and advances in technology have turned previously unrecoverable resources into major sources of domestic production. Moreover, the decline in crude oil reserves has significantly slowed over the past decade. Therefore, there would be an end to the conventional hydrocarbon resources sooner or later and, in the meantime, global natural gas consumption is projected to grow 52% from about 108 Tcf in 2009 to about 163 Tcf in 2030, which is an annual increase of almost 2%. In addition, since natural gas combustion produces less CO2 than coal and other petroleum products, governments are encouraged to use it as an alternative to other fossil fuels to reduce greenhouse gas emissions. Shale gas accumulations, with a unique all in one nature, where all petroleum system elements reside in just one lithology, have become the focus of gas exploration strategies after recent successes in the Barnett Shale gas production. Meanwhile, significant advances in drilling and stimulation technologies have made gas shale attractive for development in many countries including Iran. The unconventional gas resources such as coal bed methane and gas trapped in shale are growing in importance. Such estimated reserves account for approximately 18% of total proven gas reserves. Shale formations in particular offer enormous potential for future production. This study compares several shale gas resources in different areas and highlights the possible potential unconventional resources in Iran

    Finite quantum tomography via semidefinite programming

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    Using the the convex semidefinite programming method and superoperator formalism we obtain the finite quantum tomography of some mixed quantum states such as: qudit tomography, N-qubit tomography, phase tomography and coherent spin state tomography, where that obtained results are in agreement with those of References \cite{schack,Pegg,Barnett,Buzek,Weigert}.Comment: 25 page

    Mesenchymal stem cell-derived exosomes: A new therapeutic approach to osteoarthritis?

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    Degenerative disorders of joints, especially osteoarthritis (OA), result in persistent pain and disability and high costs to society. Nevertheless, the molecular mechanisms of OA have not yet been fully explained. OA is characterized by destruction of cartilage and loss of extracellular matrix (ECM). It is generally agreed that there is an association between pro-inflammatory cytokines and the development of OA. There is increased expression of matrix metalloproteinase (MMP) and "a disintegrin and metalloproteinase with thrombospondin motifs" (ADAMTS). Mesenchymal stem cells (MSCs) have been explored as a new treatment for OA during the last decade. It has been suggested that paracrine secretion of trophic factors, in which exosomes have a crucial role, contributes to the mechanism of MSC-based treatment of OA. The paracrine secretion of exosomes may play a role in the repair of joint tissue as well as MSC-based treatments for other disorders. Exosomes isolated from various stem cells may contribute to tissue regeneration in the heart, limbs, skin, and other tissues. Recent studies have indicated that exosomes (or similar particles) derived from MSCs may suppress OA development. Herein, for first time, we summarize the recent findings of studies on various exosomes derived from MSCs and their effectiveness in the treatment of OA. Moreover, we highlight the likely mechanisms of actions of exosomes in OA. © 2019 The Author(s)

    Effect of micro-aerobic process on improvement of anaerobic digestion sewage sludge treatment: Flow cytometry and ATP assessment

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    Micro-aeration as a pretreatment method improves the efficiency of anaerobic digestion of municipal sewage sludge and consequently promotes the methane production. In this study, adenosine triphosphate (ATP) and flow cytometry (FCM) were employed to monitor the performance of the micro-aerobic process and investigate the survival of bacterial cells within the process. At first, the effect of air flow rate (AFR) (0.1, 0.2, 0.3 and 0.5 vvm) on hydrolysis of mixed sludge in 5 aeration cycles (20, 30, 40, 48 and 60 hours) was examined. Then, the effects of the micro aerobic process on methane (CH4) production in anaerobic digestion were surveyed. The highest VSS reduction was 30.6 and 10.4 for 40 hours in the reactor and control, respectively. Soluble COD also fluctuated between 40.87 and 65.14 in micro-aerobic conditions; the highest SCOD was achieved at the time of 40 h. Microbial activities were increased by 597, 170 and 79.4 for 20, 30 and 40 h pretreatment with the micro-aerobic process, respectively. Apoptosis assay showed that micro-aerobic pre-treatment at 20, 30 and 40 h increased the percentage of living cells by 57.4, 62.8 and 67.9, respectively. On the other hand, FCM results showed that the highest percentage of viable bacteria (i.e., 67.9) was observed at 40 h pretreating which was approximately 40 higher the ones for the control. Variation in cumulative methane production shows that methane production was increased by 221 compared to anaerobic digestion (control group). Therefore, ATP and FCM can be employed as two appropriate, accurate, relatively specific indicators for monitoring the process and bacteria viability. © The Royal Society of Chemistry

    Curcumin: A new candidate for melanoma therapy?

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    Melanoma remains among the most lethal cancers and, in spite of great attempts that have been made to increase the life span of patients with metastatic disease, durable and complete remissions are rare. Plants and plant extracts have long been used to treat a variety of human conditions; however, in many cases, effective doses of herbal remedies are associated with serious adverse effects. Curcumin is a natural polyphenol that shows a variety of pharmacological activities including anti-cancer effects, and only minimal adverse effects have been reported for this phytochemical. The anti-cancer effects of curcumin are the result of its anti-angiogenic, pro-apoptotic and immunomodulatory properties. At the molecular and cellular level, curcumin can blunt epithelial-to-mesenchymal transition and affect many targets that are involved in melanoma initiation and progression (e.g., BCl2, MAPKS, p21 and some microRNAs). However, curcumin has a low oral bioavailability that may limit its maximal benefits. The emergence of tailored formulations of curcumin and new delivery systems such as nanoparticles, liposomes, micelles and phospholipid complexes has led to the enhancement of curcumin bioavailability. Although in vitro and in vivo studies have demonstrated that curcumin and its analogues can be used as novel therapeutic agents in melanoma, curcumin has not yet been tested against melanoma in clinical practice. In this review, we summarized reported anti-melanoma effects of curcumin as well as studies on new curcumin formulations and delivery systems that show increased bioavailability. Such tailored delivery systems could pave the way for enhancement of the anti-melanoma effects of curcumin. © 2016 UIC
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