481 research outputs found

    Retraction: Estimation of progression of multi-state chronic disease using the Markov model and prevalence pool concept

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    This article [1] has been retracted because the Editors are unable to ensure the scientific veracity of the findings or the ethical conduct of the authors despite an extensive investigation

    Generation of quasi-monoenergetic protons from thin multi-ion foils by a combination of laser radiation pressure acceleration and shielded Coulomb repulsion

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    We study theoretically and numerically the acceleration of protons by a combination of laser radiation pressure acceleration and Coulomb repulsion of carbon ions in a multi-ion thin foil made of carbon and hydrogen. The carbon layer helps to delay the proton layer from disruption due to the Rayleigh–Taylor instability, to maintain the quasi-monoenergetic proton layer and to accelerate it by the electron-shielded Coulomb repulsion for much longer duration than the acceleration time using single-ion hydrogen foils. Particle-in-cell simulations with a normalized peak laser amplitude of a_0 = 5 show a resulting quasi-monoenergetic proton energy of about 70 MeV with the foil made of 90% carbon and 10% hydrogen, in contrast to 10 MeV using a single-ion hydrogen foil. An analytical model is presented to explain quantitatively the proton energy evolution; this model is in agreement with the simulation results. The energy dependence of the quasi-monoenergetic proton beam on the concentration of carbon and hydrogen is also studied

    Assessing water resources vulnerability and resilience of southern Taiwan to climate change

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    Water resources management has become more challenging in Taiwan due to rapid socio-economic development and the complications of climate change. This study developed a systematic procedure for assessing water resources vulnerability and resilience with an integrated tool, TaiWAP, including climate change scenarios, a weather generator, a hydrological model, and system dynamic models. Five assessment indicators, including two for vulnerability, two for resilience, and one for availability were used to quantify changes in water resources and improvements after implementing adaption measures. Each indicator was presented with 3 grades, namely low, medium, and high. Water resources vulnerability and resilience for Tainan City in southern Taiwan were evaluated. Insufficient water supply facilities capacity is the major weakness causing low resilience. Water resources allocation flexibility is limited by substantial agricultural water demands. A total of 9 adaption measures and combinations of measures were assessed. Desalination plant implementation can steadily supply public water to lessen system failure duration. Although agricultural water conservation and fallow land can greatly reduce water demand, fallow compensation is a potential cost. When food security is considered, reducing irrigation leakage will be a better adaption measure to both water and agriculture stakeholders. Both agriculture water conservation and cropping systems adjustment have cross-spatial flexibilities. The combination of desalination, reservoirs and public water conservation provide the most beneficial effects in reducing climate change impact

    Laser acceleration of protons using multi-ion plasma gaseous targets

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    We present a theoretical and numerical study of the novel acceleration scheme by applying a combination of laser radiation pressure and shielded Coulomb repulsion in laser acceleration of protons in multi-species gaseous targets. By using a circularly polarized CO2 laser pulse with a wavelength of 10 Îźm, much greater than that of a Ti:Sapphire laser, the critical density is significantly reduced, and a high-pressure gaseous target can be used to achieve an overdense plasma. This gives us a larger degree of freedom in selecting the target compounds or mixtures, as well as their density and thickness profiles. By impinging such a laser beam on a carbon-hydrogen target, the gaseous target is first compressed and accelerated by radiation pressure until the electron layer disrupts, after which the protons are further accelerated by the electron-shielded carbon ion layer. An 80 MeV quasi-monoenergetic proton beam can be generated using a half-sine shaped laser beam with peak power 70 TW and pulse duration of 150 wave periods

    Activation of Sp1-mediated transcription by Rta of Epstein–Barr virus via an interaction with MCAF1

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    Rta is a transcription factor encoded by BRLF1 of the Epstein–Barr virus (EBV). This factor is expressed during the immediate-early stage of the lytic cycle to activate the genes required for EBV lytic development. Although transcription activation by Rta is frequently associated with the binding of Rta to the Rta-response element (RRE) in promoters, Rta sometimes activates promoters without an RRE. Here we show that Rta interacts with an Sp1-interacting protein, MBD1-containing chromatin-associated factor 1 (MCAF1). This interaction is critical to the formation of an Sp1–MCAF1–Rta complex at Sp1 sites. Therefore, following lytic induction and the expression of Rta, Rta increases Sp1-mediated transcription. The genes that are thus activated include p16, p21, SNRPN and BRLF1. However, the binding of Rta to RRE prevents the interaction between Rta and MCAF1; therefore, transcription activation by RRE depends only on Rta, and not on MCAF1 or Sp1. Furthermore, this study finds that MCAF1 promotes the expression of Rta and Zta from EBV, indicating that MCAF1 participates EBV lytic activation. Our study documents the critical role of Rta in regulating the transcription of the genes that are mediated by Sp1

    Clinical characteristics of central diabetes insipidus in Taiwanese children

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    Background/PurposeData on the clinical features of children with central diabetes insipidus (CDI) are lacking in Taiwan. This study investigated the clinical manifestations and etiology of CDI in Taiwanese children.MethodsFrom 1983 to 2012, 62 children with permanent diabetes insipidus were enrolled in the study. They were diagnosed at the Department of Pediatrics of National Taiwan University Hospital. Their medical records were thoroughly reviewed and their clinical symptoms and signs, laboratory data, and etiologies were analyzed.ResultsThe patients’ median age at diagnosis was 10 years and the median interval between initial manifestations and diagnosis was 0.5 years. The most common symptoms and signs were polyuria, polydipsia, nocturia, and growth retardation. Most patients had low urine osmolality and elevated plasma osmolality on diagnosis. Absence of a posterior pituitary hyperintense signal and thickening of the pituitary stalk were common findings on magnetic resonance imaging. Approximately 80% of the patients had anterior pituitary hormone deficiency and all patients had growth hormone deficiency. Approximately 60% of patients had intracranial lesions, the most common causes of which were germ cell tumor and Langerhans cell histiocytosis. Two patients were initially believed to have idiopathic CDI but intracranial lesions were detected during the follow-up period.ConclusionBecause a delayed diagnosis of CDI is common in Taiwanese children, a high index of suspicion is important. The underlying etiology of CDI in children may not initially be obvious. Long-term surveillance is therefore necessary, especially for the early detection of evolving treatable intracranial lesions

    Granulocyte Colony-Stimulating Factor Activating HIF-1Îą Acts Synergistically with Erythropoietin to Promote Tissue Plasticity

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    Stroke and peripheral limb ischemia are serious clinical problems with poor prognosis and limited treatment. The cytokines erythropoietin (EPO) and granulocyte-colony stimulating factor (G-CSF) have been used to induce endogenous cell repair and angiogenesis. Here, we demonstrated that the combination therapy of EPO and G-CSF exerted synergistic effects on cell survival and functional recovery from cerebral and peripheral limbs ischemia. We observed that even under normoxic conditions, G-CSF activates hypoxia-inducible factor-1Îą (HIF-1Îą), which then binds to the EPO promoter and enhances EPO expression. Serum EPO level was significantly increased by G-CSF injection, with the exception of Tg-HIF-1Îą+f/+f mice. The neuroplastic mechanisms exerted by EPO combined with G-CSF included enhanced expression of the antiapoptotic protein of Bcl-2, augmented neurotrophic factors synthesis, and promoted neovascularization. Further, the combination therapy significantly increased homing and differentiation of bone marrow stem cells (BMSCs) and intrinsic neural progenitor cells (INPCs) into the ischemic area. In summary, EPO in combination with G-CSF synergistically enhanced angiogenesis and tissue plasticity in ischemic animal models, leading to greater functional recovery than either agent alone

    Detection of EBV Infection and Gene Expression in Oral Cancer from Patients in Taiwan by Microarray Analysis

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    Epstein-Barr virus is known to cause nasopharyngeal carcinoma. Although oral cavity is located close to the nasal pharynx, the pathogenetic role of Epstein-Barr virus (EBV) in oral cancers is unclear. This molecular epidemiology study uses EBV genomic microarray (EBV-chip) to simultaneously detect the prevalent rate and viral gene expression patterns in 57 oral squamous cell carcinoma biopsies (OSCC) collected from patients in Taiwan. The majority of the specimens (82.5%) were EBV-positive that probably expressed coincidently the genes for EBNAs, LMP2A and 2B, and certain structural proteins. Importantly, the genes fabricated at the spots 61 (BBRF1, BBRF2, and BBRF3) and 68 (BDLF4 and BDRF1) on EBV-chip were actively expressed in a significantly greater number of OSCC exhibiting exophytic morphology or ulceration than those tissues with deep invasive lesions (P = .0265 and .0141, resp.). The results may thus provide the lead information for understanding the role of EBV in oral cancer pathogenesis

    The contrast in suspended particle dynamics at surface and near bottom on the river-dominated northern South China Sea shelf in summer: implication on physics and biogeochemistry coupling

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    To understand the process-response relations among physical forcing and biogeochemical properties of suspended particles (SPs) in the river-dominated northern South China Sea shelf, a 5-day shipboard observation was conducted at a fixed location on the dispersal pathway of the Zhujiang (Pearl) River plume (ZRP) in the summer of 2016. Instrumented moorings were deployed near the sampling site to record the flow and wave fields every 10 minutes. Hydrographic properties were measured hourly to identify different water masses. Water and SPs samples at the surface (3 m) and near the bottom (3 m above the bed) were taken every 3 h for the analyses of nutrients, chlorophyll-a (Chl-a), and particulate organic matter (POM including POC, PN, and δ13CPOC). Meanwhile, the grain-size composition of SPs and seafloor sediment were also analyzed. Results showed that monsoon winds drove cold upwelling and ZRP waters at the surface. Both the upwelling and ZRP regimes contained newly produced marine phytoplankton based on low POC/Chl-a ratio (PC ratio) and enriched δ13CPOC. However, SPs in the ZRP regime were smaller (<153 ¾m), having denser particle bulk density, and less enriched δ13CPOC, indicating different bio-communities from the upwelling regime. EOF analysis of the surface data suggested that mixing processes and the dispersal of the ZRP regime were mainly controlled by far-field storm winds, tidal modulation, and strength of mixing. On the other hand, a bottom nepheloid layer (BNL) was observed, mainly consisting of SPs<63 Οm with higher bulk density than SPs at the surface. POM in the BNL was degraded and δ13CPOC-depleted according to the PC ratio and δ13CPOC. EOF analysis of the near-bottom data indicated that the dominant physical processes influencing the biogeochemical properties of SPs in the BNL were jointly the upwelling-associated lateral transport (first order) and tide-related resuspension (second order). Our study identified the contrast between the surface and near-bottom regimes with the coupling patterns among physical forcing and physiochemical properties of SPs using good constraints on particle dynamics and particle sources
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