19672 research outputs found
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UV-curable alkyd coating with self-healing ability
No full textUV-curable palm oil-based alkyd coating is a form of environmentally friendly coating that utilizes vegetable oil as one of its main raw materials. Similar to any other coatings, UV-cured alkyd coating is susceptible to damages such as formation of microcracks during its service. Early diagnosis and repair of the damage are important to avoid further catastrophic failure and damage to the substrate. Self-healing ability in coating is therefore a desirable quality and has gained popularity in the industry as it can prolong the lifetime of the coating, as well as the substrate. The aim of this study is to produce UV-curable alkyd coating with self-healing ability. The coating is a form of environmentally friendly self-healing coating owing to its UV curing ability and also due to the fact that the binder is produced using a significant amount of a renewable resource, palm oil. The self-healing alkyd coating is comprised of microcapsules containing healing agent, embedded into alkyd coating matrix. Diglycidyl ether bisphenol-A-based epoxy (EPON828) and pentaerythritol tetrakis (3-mercaptopropionate) were chosen as the healing agents in this work due to their compatibility with the matrix. Self-healing process of the coating takes place within 10 min after the coating was intentionally damaged. The efficacy of the self-healing ability of the coating was investigated using electrochemical impedance spectroscopy measurement. © 2018, American Coatings Association
Expression of proteins related to thyroid hormone function in the uterus is down‐regulated at the day of implantation in hypothyroid pregnant rats
No full textHypothyroidism has been linked to infertility, but the mechanisms underlying infertility-related hypothyroidism have yet to be fully elucidated. Therefore, in this study, effects of hypothyroidism on expression of the proteins related to thyroid hormone function in the uterus, which were thought to play a role implantation, including thyroid hormone receptor (TR), thyroid stimulating hormone receptor (TSHR), retinoic acid receptor (RAR) and extracellular kinase (ERK) were identified. Pregnant female rats were rendered hypothyroid by giving methimazole (MMI), orally. Following hypothyroid induction, rats were grouped into control (non-treated) and received subcutaneous thyroxine at 20, 40, and 80 μg/kg/day for five consecutive days. At Day 6, which is the day of implantation (GD 6), rats were sacrificed and the number of embryo implantation site in the uterus was calculated. Then, uterine horns were harvested and expression of the above proteins and their mRNAs were identified by Western blotting and real-time PCR, respectively. In non-treated hypothyroid pregnant rats, the number of embryo implantation sites decreased as compared to euthyroid and hypothyroid rats receiving thyroxine treatment. Similarly, expression of TRα-1, TRβ-1, TSHR, ERK1/2 and RAR proteins and mRNA in the uterus of non-treated hypothyroid rats also decreased (P < 0.05 when compared to euthyroid and thyroxine-treated hypothyroid rats). In conclusion, downregulated expression of the thyroid hormone related proteins in the uterus at the day of implantation might result in infertility as reported in hypothyroid condition. © 2019 International Federation for Cell Biolog
Generation of Microsecond Ytterbium-Doped Fiber Laser Pulses using Bismuth Telluride Thin Film as Saturable Absorber
No full textBismuth telluride (Bi2Te3), a type of topological insulators, is currently in hot pursuit due to its unique physical properties. Therefore, this paper describes a simple Q-switched Ytterbium-doped fiber laser (YDFL) by using Bi2Te3 thin-film as saturable absorber. The few layers Bi2Te3 film was fabricated using optical deposition technique and subsequently, was used in an all-fiber, YDFL setup. As a result, a self-starting Q-switching pulses were first occurred when the laser pumping power reached 88.6 mW. As the pump power level increased, the observed pulses repetition rates had increased steadily from 17 to 29.63 kHz. Hence, this work demonstrated that Bi2Te3 thin-film can be used to successfully generate Q-switching pulses at 1-micron region and is well suited for many photonic applications operated at this wavelength region. © 2019 Penerbit Universiti Kebangsaan Malaysia. All rights reserved
Avalanche charge generation in anhydrous glucosides excited by an external electric field
No full textGlycolipids are components of cellular membranes comprising a hydrophobic lipid tail and one or more hydrophilic sugar heads, and are widely associated with the fields of life science and biochemistry. Due to the hygroscopic nature of sugar, the dry thermotropic phases of glycolipids have fewer studies. We report on the electric charge generation in anhydrous glucosides excited by the external high electric field (∼2 MV/m). This causes a large current in the smectic A phase, but not in the isotropic phase. Its intensity is about 100 times larger than the steady state current. The generation of the current was found to be irreversible by the repetition of the field application. The large electric carrier generation is originated in the smectic A phase, possibly due to an electron avalanche breakdown mechanism caused by the collisions of electrons through the impact ionization. © 2019 Author(s)
Novel dibenzothiophene chromophores with peripheral barbituric acceptors
No full textA series of novel chromophores based on central 2,8-disubstituted dibenzothiophene (DBT) or dibenzothiophene-S,S-dioxide (DBTO) has been designed and prepared. The interconnection of DBT(O) central scaffold with two peripheral barbituric acceptors via various π-spacer allowed significant property tuning of target chromophores. Four new final chromophores and six DBT(O)-intermediates have been successfully synthesized and fully characterized. Experimental and calculated data showed that the fundamental properties are affected by the chromophore A-π-D-π-A or A-π-A-π-A arrangement (DBT vs. DBTO) and the π-linker (ethenylene vs. ethynylene). Thorough structure-property relationships have been elucidated and discussed in detail. © 2019 Elsevier Lt
Differential transcriptome analysis of the disease tolerant Madagascar–Malaysia crossbred black tiger shrimp, Penaeus monodon hepatopancreas in response to acute hepatopancreatic necrosis disease (AHPND) infection: inference on immune gene response and interaction
No full textBackground: Penaeus monodon is the second most widely cultured marine shrimp species in the global shrimp aquaculture industry. However, the growth of P. monodon production has been constantly impaired by disease outbreaks. Recently, there is a lethal bacterial infection, known as acute hepatopancreatic necrosis disease (AHPND) caused by Vibrio parahaemolyticus AHPND strain (Vp AHPND), which led to mass mortalities in P. monodon. Unfortunately, there is still insufficient knowledge about the underlying immune response of P. monodon upon AHPND infection. The present study aims to provide an insight into the antibacterial immune response elicited by P. monodon hepatopancreas towards AHPND infection. Methods: We have employed high-Throughput RNA-Seq technology to uncover the transcriptome changes of P. monodon hepatopancreas when challenged with Vp AHPND. The shrimps were challenged with Vp AHPND through immersion method with dissected hepatopancreas samples for the control group (APm-CTL) and treatment group at 3 (APm-T3), 6 (APm-T6), and 24 (APm-T24) hours post-AHPND infection sent for RNA-Seq. The transcriptome de novo assembly and Unigene expression determination were conducted using Trinity, Tgicl, Bowtie2, and RSEM software. The differentially expressed transcripts were functionally annotated mainly through COG, GO, and KEGG databases. Results: The sequencing reads generated were filtered to obtain 312.77 Mb clean reads and assembled into 48662 Unigenes. Based on the DEGs pattern identified, it is inferred that the PAMPs carried by Vp AHPND or associated toxins are capable of activating PRRs, which leads to subsequent pathway activation, transcriptional modification, and antibacterial responses (Phagocytosis, AMPs, proPO system). DAMPs are released in response to cell stress or damage to further activate the sequential immune responses. The comprehensive interactions between Vp AHPND, chitin, GbpA, mucin, chitinase, and chitin deacetylase were postulated to be involved in bacterial colonization or antibacterial response. Conclusions: The outcomes of this research correlate the different stages of P. monodon immune response to different time points of AHPND infection. This finding supports the development of biomarkers for the detection of early stages of Vp AHPND colonization in P. monodon through host immune expression changes. The potential genes to be utilized as biomarkers include but not limited to C-Type lectin, HMGB1, IMD, ALF, serine proteinase, and DSCAM. © 2019 The Author(s)
Endogenous Annexin-A1 Negatively Regulates Mast Cell-Mediated Allergic Reactions
No full textMast cell stabilizers like cromoglycate and nedocromil are mainstream treatments for ocular allergy. Biochemical studies in vitro suggest that these drugs prevent mast cell degranulation through the release of Annexin-A1 (Anx-A1) protein. However, the direct effect of Anx-A1 gene deletion on mast cell function in vitro and in vivo is yet to be fully investigated. Hence, we aim to elucidate the role of Anx-A1 in mast cell function, both in vivo and in vitro, using a transgenic mouse model where the Anx-A1 gene has been deleted. Bone marrow-derived mast cells (BMDMCs) were cultured from wild-type animals and compared throughout their development to BMDMCs obtained from mice lacking the Anx-A1 gene. The mast cell differentiation, maturity, mediator, and cytokine release were explored using multiple biochemical techniques, such as Western blots, ELISA, and flow cytometry analysis. Electron microscopy was used to identify metachromatic granules content of cells. For in vivo studies, Balb/C wild-type and Anx-A1-deficient mice were divided into the following groups: group 1, a control receiving only saline, and group 2, which had been sensitized by prior exposure to short ragweed (SRW) pollen by topical contact with the conjunctival mucosae. Allergic conjunctivitis was evaluated blind after 24 h by trained observers scoring clinical signs. Electron micrographs of BMDMCs from Anx-A1-null mice revealed more vacuoles overall and more fused vacuoles than wild-type cells, suggesting enhanced secretory activity. Congruent with these observations, BMDMCs lacking the Anx-A1 gene released significantly increased amounts of histamine both spontaneously as well as in response to Ig-E-FcεRI cross-linking compared to those from wild-type mice. Interestingly, the spontaneous release of IL-5, IL-6, IL-9, and monocyte chemoattractant protein-1 (MCP-1) were also markedly increased with a greater production observed upon IgE cross-linking. This latter finding is congruent with augmented calcium mobilization in BMDMCs lacking the Anx-A1 gene. In vivo, when compared to wild-type animals, Anx-A1-deficient mice exposed to SRW pollen displayed exacerbated signs and symptoms of allergic conjunctivitis. Taken together, these results suggest Anx-A1 is an important non-redundant regulator of mast cell reactivity and particularly in allergen mediated allergic reactions. © 2019 Sinniah, Yazid, Bena, Oliani, Perretti and Flower. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms
ANNs and inflow forecast to aid stochastic optimization of reservoir operation
No full textImplicit stochastic reservoir optimization (ISO) typically utilizes nonlinear regression to correlate release as a function of initial storage plus inflow forecasted for the month. This study shows that improved ISO-based policies can be derived by replacing current-month forecast and regression for long-term mean inflow forecast (LTF) and artificial neural networks (ANN), respectively. The ISO-LTF-ANN approach is applied to the Aswan High Dam reservoir, Egypt. First, perfect-forecast deterministic optimization (PFDO) defines operation strategies for 100 scenarios of 100-year inflows. Then, optimal release and storage data are grouped into databases corresponding to different forecast horizons. Next, ANNs are trained for each database to serve as release policies. Later, the policies are used to operate the system under other scenarios. Operations by the standard operation policy (SOP), stochastic dynamic programming (SDP) and PFDO are employed for comparison. ISO-LTFANN performs near PFDO and better than SOP, SDP and a regression-based ISO-LTF approach. © 2019, © 2019 IAHR and WCCE
N-(2-hydroxyphenyl)acetamide and its gold nanoparticle conjugation prevent glycerol-induced acute kidney injury by attenuating inflammation and oxidative injury in mice
No full textThe protective activity of N-(2-hydroxyphenyl)acetamide (NA-2) and NA-2-coated gold nanoparticles (NA-2-AuNPs) in glycerol-treated model of acute kidney injury (AKI) in mice was investigated. NA-2 (50 mg/kg) and NA-2-AuNPs (30 mg/kg) were given to the animals for four days followed by 24-h water deprivation and injection of 50% glycerol (10 ml/kg im). The animals were sacrificed on the next day. Blood and kidneys were collected for biochemical investigations (urea and creatinine), histological studies (hematoxylin and eosin; and periodic acid-Schiff staining), immunohistochemistry (actin and cyclooxygenase-2, Cox-2), and real-time RT-PCR (inducible nitric oxide synthase, iNOS; nuclear factor-κB p50, NFκB; hemeoxygenase-1, HO-1; and kidney injury molecule-1, Kim-1). NA-2 protected renal tubular necrosis and inflammation, though the result of NA-2-AuNPs was better than compound alone and it also exhibited the activity at far less dose. The test compound and its gold nano-formulation decreased the levels of serum urea and creatinine level in the treated animals. Both NA-2 and NA-2-AuNPs also conserved actin cytoskeleton, and lowered COX-2 protein expression. Moreover, the mRNA expressions of iNOS and NFkB p50 were down-regulated, and HO-1 and Kim-1 genes were up-regulated. We conclude that NA-2 and NA-2-AuNPs ameliorates kidney inflammation and injury in glycerol-induced AKI animal model via anti-oxidant and anti-inflammatory mechanisms which make it a suitable candidate for further studies. We believe that these findings will contribute in the understanding of the mechanism of action of paracetamol-like drugs and can be considered for clinical research for the prevention of AKI. © 2018, Springer Science+Business Media, LLC, part of Springer Nature
A new fractal-based kinetic index to characterize gait deficits with application in stroke survivor functional mobility assessment
No full textThis paper proposes a new Kinetic Index (K.I.) to characterize the gait deficits in stroke survivors. The index is derived from the fractal properties of surface electromyography (sEMG) signals. The objectives of proposing this K.I. are (i) to find the correlation between sEMG fractal properties with TUG test; (ii) to classify stroke survivors into different homogeneous subgroups based on K.I., and (iii) to compare the classification results based on published methods. To achieve these objectives, 30 stroke survivors with different levels of gait impairments were recruited to perform TUG. sEMG signals from Tibialis Anterior (TA) and Gastrocnemius Lateral (GL) were acquired in a 5-meter walk test. Sliding window Higuchi fractal dimension algorithm was applied to sEMG of these TA and GL muscles to determine the fractal properties. Hierarchical cluster analysis was used to classify stroke survivors into different subgroups with (i) conventional multiple category of gait parameters (Approach 1), and (ii) single input by using the proposed K.I. value (Approach 2). Besides that, classification based on stroke survivors TUG score was also applied. Results showed that K.I. has strong correlation with the TUG score. A higher value in K.I. associates with higher TUG score. This suggests K.I. could quantify gait deficits and detect risk of fall in this population. The classification results from the Approach 1 were similar to previous published studies. The gait parameters from Approach 2 showed similar gait patterns to Approach 1. Meanwhile, gait results from classification based on TUG score yielded heterogeneous subgroups. These results suggested that K.I. was able to assess gait severity among stroke survivors and was more efficient (it requires a single input parameter only) to classify stroke survivors into homogeneous subgroups. © 2018 Elsevier Lt