800 research outputs found

    Reproductive seasonality and maturation of the sergestid shrimp, Acetes japonicus (Decapoda: Sergestidae) in coastal waters of Malacca, Peninsular Malaysia

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    Sex ratio, length at first maturity and spawning season of the sergestid shrimp (Acetes japonicus) were investigated between April 2006 and March 2007 in coastal waters of Klebang Besar, Malacca, Peninsular Malaysia. Klebang Besar waters are one of the main fishing grounds for A. japonicus in the Peninsular Malaysia. The overall annual sex ratio was found to be 1:1.46 (males: females). The spawning season was March to July with peak in May, however there was also some spawning in October to November. The female attained sexual maturity at a minimum size of 17.5 mm total length. The matured and near to spawn stages (II and III) occurred more than 50% in every month except in August. Therefore, it may be inferred that A. japonicus breeds continuously throughout the year in the coastal waters of Malacca, Peninsular Malaysia.Key words: Spawning, sex ratio, maturity, Acetes japonicus

    Integration of Phase Change Material in the Design of Solar Concentrator-Based Water Heating System.

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    Indonesia has been blessed with excellent solar heat distribution, which can be used as renewable energy to heat water. Various technologies have been developed to utilize these inexhaustible thermodynamic resources, in the form of photons arrays, converted into concentrated heat for daily use, i.e., solar water heater. This renewable-based water heating system can provide significant energy efficiency, benefit the environment, and reduce energy use costs. This experimental study attempts to harvest the energy from the sun using a cylindrical through collector (CTC) type solar concentrator. The CTC was made of the solar reflective film (SRF) affixed to concentrator collector surfaces which was then mounted on an adjustable angle frame of the concentrator collector support. The heat generated from the concentrator was stored in water, and phase change material is embedded in the system to retain the heat longer. The research was carried out in Langsa City, Aceh, Indonesia. The results showed that water heaters using CTC systems could produce 16 L of hot water retained at 40-60 °C for four hours. With the addition of beeswax, the water temperature of the same capacity can be maintained at 40-60 °C for around 5 h. This technology demonstrated an excellent result that produces as much as 60 L of water per day, increasing solar thermal energy efficiency. This technology presented a great potential for replication or even for further development on an industrial scale

    Non-controlled fault current limiter to improve fault ride through capability of DFIG-based wind turbine

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    In this paper, a non-controlled fault current limiter (FCL) is proposed to improve fault ride through capability of doubly fed induction generator (DFIG)-based wind turbine. Cooperative operation of chopper circuit and the non-controlled FCL, which is located in rotor side of the DFIG, is studied. It is demonstrated that locating the proposed topology in the rotor side is effective from leakage coefficient point of view in limiting transient over currents rather than stator side. Furthermore, it is shown that, by obtaining optimum non-superconducting reactor value, rate of fault current change is limited to lower than maximum rate of current change in semiconductor switches of the DFIG’s converters during fault. Design methodology of non-superconducting reactor value is investigated. Operation of the non-controlled FCL in the rotor side is compared to crowbar protection scheme and results will be discussed. PSCAD/EMTDC software is employed to simulate the proposed scheme and prove its effectiveness

    Fiberoptic endoscopic evaluation of swallowing in intensive care unit patients

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    Aspiration in critically ill patients frequently causes severe co-morbidity. We evaluated a diagnostic protocol using routine FEES in critically ill patients at risk to develop aspiration following extubation. We instructed intensive care unit physicians on specific risk factors for and clinical signs of aspiration following extubation in critically ill patients and offered bedside FEES for such patients. Over a 45-month period, we were called to perform 913 endoscopic examinations in 553 patients. Silent aspiration or aspiration with acute symptoms (cough or gag reflex as the bolus passed into the trachea) was detected in 69.3% of all patients. Prolonged non-oral feeding via a naso-gastric tube was initiated in 49.7% of all patients. In 13.2% of patients, a percutaneous endoscopic gastrostomy was initiated as a result of FEES findings, and in 6.3% an additional tracheotomy to prevent aspiration had to be initiated. In 59 out of 258 patients (22.9%), tracheotomies were closed, and 30.7% of all 553 patients could be managed with the immediate onset of an oral diet and compensatory treatment procedures. Additional radiological examinations were not required. FEES in critically ill patients allows for a rapid evaluation of deglutition and for the immediate initiation of symptom-related rehabilitation or for an early resumption of oral feeding

    Metabolic coupling in urothelial bladder cancer compartments and its correlation to tumour aggressiveness

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    Monocarboxylate transporters (MCTs) are vital for intracellular pH homeostasis by extruding lactate from highly glycolytic cells. These molecules are key players of the metabolic reprogramming of cancer cells, and evidence indicates a potential contribution in urothelial bladder cancer (UBC) aggressiveness and chemoresistance. However, the specific role of MCTs in the metabolic compartmentalization within bladder tumors, namely their preponderance on the tumor stroma, remains to be elucidated. Thus, we evaluated the immunoexpression of MCTs in the different compartments of UBC tissue samples (n = 111), assessing the correlations among them and with the clinical and prognostic parameters. A significant decrease in positivity for MCT1 and MCT4 occurred from normoxic toward hypoxic regions. Significant associations were found between the expression of MCT4 in hypoxic tumor cells and in the tumor stroma. MCT1 staining in normoxic tumor areas, and MCT4 staining in hypoxic regions, in the tumor stroma and in the blood vessels were significantly associated with UBC aggressiveness. MCT4 concomitant positivity in hypoxic tumor cells and in the tumor stroma, as well as positivity in each of these regions concomitant with MCT1 positivity in normoxic tumor cells, was significantly associated with an unfavourable clinicopathological profile, and predicted lower overall survival rates among patients receiving platinum-based chemotherapy. Our results point to the existence of a multi-compartment metabolic model in UBC, providing evidence of a metabolic coupling between catabolic stromal and cancer cells' compartments, and the anabolic cancer cells. It is urgent to further explore the involvement of this metabolic coupling in UBC progression and chemoresistance.This study was supported by the Life and Health Sciences Research Institute (ICVS) from the School of Health Sciences of the University of Minho. JA received a postdoctoral fellowship from ICVS (reference ICVS-SSRL: ON.2 SR&TD Integrated Program, NORTE-07-0124-FEDER-000017).info:eu-repo/semantics/publishedVersio

    Photo-antagonism of the GABAA receptor

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    Neurotransmitter receptor trafficking is fundamentally important for synaptic transmission and neural network activity. GABAA receptors and inhibitory synapses are vital components of brain function, yet much of our knowledge regarding receptor mobility and function at inhibitory synapses is derived indirectly from using recombinant receptors, antibody-tagged native receptors and pharmacological treatments. Here we describe the use of a set of research tools that can irreversibly bind to and affect the function of recombinant and neuronal GABAA receptors following ultraviolet photoactivation. These compounds are based on the competitive antagonist gabazine and incorporate a variety of photoactive groups. By using site-directed mutagenesis and ligand-docking studies, they reveal new areas of the GABA binding site at the interface between receptor β and α subunits. These compounds enable the selected inactivation of native GABAA receptor populations providing new insight into the function of inhibitory synapses and extrasynaptic receptors in controlling neuronal excitation
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