80 research outputs found
Photothermal Polymer Nanocomposites of Tungsten Bronze Nanorods with Enhanced Tensile Elongation at Low Filler Contents
We present polymer nanocomposites of tungsten bronze nanorods (TBNRs) and ethylene propylene diene monomers (EPDM). The combination of these components allows the simultaneous enhancement in the mechanical and photothermal properties of the composites at low filler contents. The as-synthesized TBNRs had lengths and diameters of 14.0 +/- 2.4 nm and 2.5 +/- 0.5 nm, respectively, and were capped with oleylamine, which has a chemical structure similar to EPDM, making the TBNRs compatible with the bulk EPDM matrix. The TBNRs absorb a wide range of near-infrared light because of the sub-band transitions induced by alkali metal doping. Thus, the nanocomposites of TBNRs in EPDM showed enhanced photothermal properties owing to the light absorption and subsequent heat emission by the TBNRs. Noticeably, the nanocomposite with only 3 wt% TBNRs presented significantly enhanced tensile strain at break, in comparison with those of pristine EPDM, nanocomposites with 1 and 2 wt % TBNRs, and those with tungsten bronze nanoparticles, because of the alignment of the nanorods during tensile elongation. The photothermal and mechanical properties of these nanocomposites make them promising materials for various applications such as in fibers, foams, clothes with cold weather resistance, patches or mask-like films for efficient transdermal delivery upon heat generation, and photoresponsive surfaces for droplet transport by the thermocapillary effect in microfluidic devices and microengines
An Advanced Operational Approach for Tropical Cyclone Center Estimation Using Geostationary-Satellite-Based Water Vapor and Infrared Channels
Tropical cyclones (TCs) are destructive natural disasters. Accurate prediction and monitoring are important to mitigate the effects of natural disasters. Although remarkable efforts have been made to understand TCs, operational monitoring information still depends on the experience and knowledge of forecasters. In this study, a fully automated geostationary-satellite-based TC center estimation approach is proposed. The proposed approach consists of two improved methods: the setting of regions of interest (ROI) using a score matrix (SCM) and a TC center determination method using an enhanced logarithmic spiral band (LSB) and SCM. The former enables prescreening of the regions that may be misidentified as TC centers during the ROI setting step, and the latter contributes to the determination of an accurate TC center, considering the size and length of the TC rainband in relation to its intensity. Two schemes, schemes A and B, were examined depending on whether the forecasting data or real-time observations were used to determine the initial guess of the TC centers. For each scheme, two models were evaluated to discern whether SCM was combined with LSB for TC center determination. The results were investigated based on TC intensity and phase to determine the impact of TC structural characteristics on TC center determination. While both proposed models improved the detection performance over the existing approach, the best-performing model (i.e., LSB combined with SCM) achieved skill scores (SSs) of +17.4% and +20.8% for the two schemes. In particular, the model resulted in a significant improvement for strong TCs (categories 4 and 5), with SSs of +47.8% and +72.8% and +41.2% and +72.3% for schemes A and B, respectively. The research findings provide an improved understanding of the intensity- and phase-wise spatial characteristics of TCs, which contributes to objective TC center estimation
International Network Performance and Security Testing Based on Distributed Abyss Storage Cluster and Draft of Data Lake Framework
An atypical epigenetic mechanism affects uniparental expression of Pol IV-dependent siRNAs.
BACKGROUND: Small RNAs generated by RNA polymerase IV (Pol IV) are the most abundant class of small RNAs in flowering plants. In Arabidopsis thaliana Pol IV-dependent short interfering (p4-si)RNAs are imprinted and accumulate specifically from maternal chromosomes in the developing seeds. Imprinted expression of protein-coding genes is controlled by differential DNA or histone methylation placed in gametes. To identify epigenetic factors required for maternal-specific expression of p4-siRNAs we analyzed the effect of a series of candidate mutations, including those required for genomic imprinting of protein-coding genes, on uniparental expression of a representative p4-siRNA locus. RESULTS: Paternal alleles of imprinted genes are marked by DNA or histone methylation placed by DNA METHYLTRANSFERASE 1 or the Polycomb Repressive Complex 2. Here we demonstrate that repression of paternal p4-siRNA expression at locus 08002 is not controlled by either of these mechanisms. Similarly, loss of several chromatin modification enzymes, including a histone acetyltransferase, a histone methyltransferase, and two nucleosome remodeling proteins, does not affect maternal expression of locus 08002. Maternal alleles of imprinted genes are hypomethylated by DEMETER DNA glycosylase, yet expression of p4-siRNAs occurs irrespective of demethylation by DEMETER or related glycosylases. CONCLUSIONS: Differential DNA methylation and other chromatin modifications associated with epigenetic silencing are not required for maternal-specific expression of p4-siRNAs at locus 08002. These data indicate that there is an as yet unknown epigenetic mechanism causing maternal-specific p4-siRNA expression that is distinct from the well-characterized mechanisms associated with DNA methylation or the Polycomb Repressive Complex 2
Real-Life Efficacy and Tolerability of Lacosamide in Pediatric Patients Aged 4 Years or Older with Drug-Resistant Epilepsy
Purpose The aim of this study was to evaluate the efficacy and safety of adjunctive lacosamide therapy in pediatric patients aged ≥4 years with drug-resistant epilepsy (DRE). Methods Medical records of children aged 4 to 19 years treated with lacosamide as adjunctive therapy for DRE were retrospectively reviewed. The patients were divided into two groups according to their age at the start of lacosamide treatment: group A (aged 4–15 years) and group B (aged 16–19 years). Changes in seizure frequency from baseline, adverse events, and the retention rate were evaluated at each follow-up visit. Results Sixty-two patients (33 males and 29 females) with a mean age of 11.4 years (range, 4 to 19) were included. The mean duration of follow-up was 20.1±12.9 months. The mean maintenance dose of lacosamide was 6.7±4.8 mg/kg/day. Forty-two patients (67.7%) were responders (≥50% reduction in seizures) with 19.4% (12/62) achieving freedom from seizures. The response rate did not differ significantly between groups A and B (67.6% vs. 68.0%, P=0.795) and was not affected by the concomitant use of sodium channel blockers. Significant independent factors associated with a good response to lacosamide treatment were a shorter duration of epilepsy (P=0.035) and fewer concomitant anti-seizure medications (P=0.002). Mild transient adverse events were observed in 20 patients (32.3%). Conclusion Lacosamide adjunctive therapy was efficacious and tolerated in children aged ≥4 years with DRE. Early use of lacosamide may be helpful for a good response to drug-resistant seizures
Strong Bathochromic Shift of Conjugated Polymer Nanowires Assembled with a Liquid Crystalline Alkyl Benzoic Acid via a Film Dispersion Process
We present aqueous dispersions of conjugated polymer nanowires (CPNWs) with improved light absorption properties aimed at aqueous-based applications. We assembled films of a donor???acceptor-type conjugated polymer and liquid crystalline 4-n-octylbenzoic acid by removing a cosolvent of their mixture solutions, followed by annealing of the films, and then formed aqueous-dispersed CPNWs with an aspect ratio >1000 by dispersing the films under ultrasonication at a basic pH. X-ray and spectroscopy studies showed that the polymer and liquid crystal molecules form independent domains in film assemblies and highly organized layer structures in CPNWs. Our ordered molecular assemblies in films and aqueous dispersions of CPNWs open up a new route to fabricate nanowires of low-band-gap linear conjugated polymers with the absorption maximum at 794 nm remarkably red-shifted from 666 nm of CPNWs prepared by an emulsion process. Our results suggest the presence of semicrystalline polymorphs ??1 and ??2 phases in CPNWs due to long-range ??????? stacking of conjugated backbones in compactly organized lamellar structures. The resulting delocalization with a reduced energy bang gap should be beneficial for enhancing charge transfer and energy-conversion efficiencies in aqueous-based applications such as photocatalysis
The United States COVID-19 Forecast Hub dataset
Academic researchers, government agencies, industry groups, and individuals have produced forecasts at an unprecedented scale during the COVID-19 pandemic. To leverage these forecasts, the United States Centers for Disease Control and Prevention (CDC) partnered with an academic research lab at the University of Massachusetts Amherst to create the US COVID-19 Forecast Hub. Launched in April 2020, the Forecast Hub is a dataset with point and probabilistic forecasts of incident cases, incident hospitalizations, incident deaths, and cumulative deaths due to COVID-19 at county, state, and national, levels in the United States. Included forecasts represent a variety of modeling approaches, data sources, and assumptions regarding the spread of COVID-19. The goal of this dataset is to establish a standardized and comparable set of short-term forecasts from modeling teams. These data can be used to develop ensemble models, communicate forecasts to the public, create visualizations, compare models, and inform policies regarding COVID-19 mitigation. These open-source data are available via download from GitHub, through an online API, and through R packages
Low Dose Astaxanthin Treatments Trigger the Hormesis of Human Astroglioma Cells by Up-Regulating the Cyclin-Dependent Kinase and Down-Regulated the Tumor Suppressor Protein P53
Astaxanthin (AXT) is a xanthophyll carotenoid known to have potent anti-cancer effects via upregulation of the intracellular reactive oxygen species (ROS) levels, which triggers apoptosis of cancer cells. While several studies have shown that AXT has potential as an anti-cancer drug, its effects in glioblastoma multiforme cells remain relatively unknown. In this study, we investigated the effects of AXT in the astroglioma cell lines U251-MG, T98G, and CRT-MG. We found that the response to AXT varied between cell lines. Moreover, U251-MG cells showed a specific hormetic response to AXT. At high concentrations (20–40 μM), AXT triggered apoptosis in U251-MG cells, as it has been previously shown in other cancer cell lines. However, low concentrations (4–8 μM) of AXT were found to upregulate the proliferative cell cycle. Furthermore, at low concentrations, AXT did not affect the intracellular ROS levels, while the superoxide dismutase activity increased moderately. Western blot analysis showed that treatment with a low concentration of AXT upregulated cyclin-dependent kinase (Cdk) 2 and p-Cdk2/3 levels and downregulated the expression of tumor protein p53. Thus, our results showed that AXT has a hormetic effect in the astroglioma cell line U251-MG
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Regulation of Imprinted Gene and Small RNA Expression in the Arabidopsis Endosperm
The Arabidopsis endosperm is an unique tissue to angiosperms, and is the main tissue where imprinting occurs. Using high-throughput sequencing we found 123 new imprinted genes and expect that the total number of imprinted genes present in the endosperm ranges from 200-500. From the 114 maternally expressed imprinted genes we found 29 genes which expression mechanism are controlled by DNA methylation and/or PcG activity. For the rest of imprinted genes and presumably the majority of p4-siRNAs, the maternal expression may be controlled by other mechanisms or use homolog of known imprinting proteins
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