318 research outputs found

    Disk emission and atmospheric absorption lines in black hole candidate 4U 1630-472

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    We re-analyzed SUZAKU data of the black hole candidate 4U 1630-472 being in the high/soft state. We show that the continuum X-ray spectrum of 4U 1630-472 with iron absorption lines can be satisfactorily modeled by the spectrum from an accretion disk atmosphere. Absorption lines of highly ionized iron originating in hot accretion disk atmosphere can be an alternative or complementary explanation to the wind model usually favored for these type of sources. We model continuum and line spectra using a single model. Absorption lines of highly ionized iron can origin in upper parts of the disk atmosphere which is intrinsically hot due to high disk temperature. Iron line profiles computed with natural, thermal and pressure broadenings match very well observations. We showed that the accretion disk atmosphere can effectively produce iron absorption lines observed in 4U 1630-472 spectrum. Absorption line arising in accretion disk atmosphere is the important part of the observed line profile, even if there are also other mechanisms responsible for the absorption features. Nevertheless, the wind theory can be an artifact of the fitting procedure, when the continuum and lines are fitted as separate model components.Comment: 10 pages, 4 figures, accepted by Astronomy and Astrophysic

    Microcapsule-based techniques for improving the safety of lithium-ion batteries

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    Lithium-ion batteries are vital energy storage devices due to their high specific energy density, lack of memory effect, and long cycle life. While they are predominantly used in small consumer electronics, new strategies for improving battery safety and lifetime are critical to the successful implementation of high-capacity, fast-charging materials required for advanced Li-ion battery applications. Currently, the presence of a volatile, combustible electrolyte and an oxidizing agent (Lithium oxide cathodes) make the Li-ion cell susceptible to fire and explosions. Thermal overheating, electrical overcharging, or mechanical damage can trigger thermal runaway, and if left unchecked, combustion of battery materials. To improve battery safety, autonomic, thermally-induced shutdown of Li-ion batteries is demonstrated by depositing thermoresponsive polymer microspheres onto battery anodes. When the internal temperature of the cell reaches a critical value, the microspheres melt and conformally coat the anode and/or separator with an ion insulating barrier, halting Li-ion transport and shutting down the cell permanently. Charge and discharge capacity is measured for Li-ion coin cells containing microsphere-coated anodes or separators as a function of capsule coverage. Scanning electron microscopy images of electrode surfaces from cells that have undergone autonomic shutdown provides evidence of melting, wetting, and re-solidification of polyethylene (PE) into the anode and polymer film formation at the anode/separator interface.As an extension of this autonomic shutdown approach, a particle-based separator capable of performing autonomic shutdown, but which reduces the shorting hazard posed by current bi- and tri-polymer commercial separators, is presented. This dual-particle separator is composed of hollow glass microspheres acting as a physical spacer between electrodes, and PE microspheres to impart autonomic shutdown functionality. An oil immersion technique is developed to simulate an overheating condition while the cell is cycling. Experimental protocols are developed to assess the performance of the separator in terms of its ability to perform autonomic shutdown and examine tested battery materials using scanning electron microscopy. Another approach to improving battery functionality is via the microencapsulation of battery additives. Currently, additives are added directly into a battery electrolyte, and while they typically perform their function given a sufficient loading, these additives often do so at the expense of battery performance. Microencapsulation allows for a high loading of additives to be incorporated into the cell and their release triggered only when and where they are needed. In this work, microencapsulation techniques are developed to successfully encapsulate 3-hexylthiophene, a stabilizing agent for high-voltage cathodes in Li-ion batteries and conductive polymer precursor, as well as the flame retardant Tris(2-choloroethyl phosphate) (TCP). Microcapsules containing 3-hexylthiophene are coated onto model battery electrodes and immersed in electrolyte. The microcapsule shell wall insulates the 3-hexylthiophene until the microcapsules are mechanically crushed and electropolymerization of the released core to form poly(3-ht) occurs under cyclic voltammetry. In addition, TCP was encapsulated using in situ polymerization. TCP-containing microcapsules are stable in electrolyte at room temperature, but are thermally triggered to release their payload at elevated temperatures. Experimental protocols are developed to study the in situ triggering and release of microencapsulated additives

    Smoking Prevalence, Attitudes and Behavior among Dental Students in Poland and Italy

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    The aim of the study was to perform preliminary research to compare the smoking prevalence, attitudes and behavior between dentistry students in two universities in Europe using the standardized Global Health Professions Student Survey (GHPSS) questionnaire. This was cross-sectional carried out among dentistry students from the Medical University in Bialystok, Poland and Sapienza University of Rome, Italy. There were 582 participants; 282 were Italians, 202 were smokers and 42% were Italians. The response rate was 79.9% of Italian students and 79.6% of Polish students. The prevalence of smoking was significantly higher among Italian students (42% vs. 28.0%). Attitudes and behaviour of smokers and non-smokers differed statistically. Polish and Italian dental students presented statistically different behavior regarding the time to smoke the first cigarette, the willingness to stop smoking and trying to stop smoking in the last year. The multiple logistic regression analysis revealed that two independent variables, exposure to second-hand smoke (SHS) both at home and in public places (OR = 3.26 and OR = 5.9, respectively), showed a significantly higher occurrence of smoking. There is a high use of tobacco among dental students, which is particularly high in Italian dental students. Students realizes the positive perception of their own tobacco counsellor role in a dental setting. Dental students should be role models to their peers and patients.publishedVersio

    Assessment of Runoff and Sediment Yields Using the AnnAGNPS Model in a Three-Gorge Watershed of China

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    Soil erosion has been recognized as one of the major threats to our environment and water quality worldwide, especially in China. To mitigate nonpoint source water quality problems caused by soil erosion, best management practices (BMPs) and/or conservation programs have been adopted. Watershed models, such as the Annualized Agricultural Non-Point Source Pollutant Loading model (AnnAGNPS), have been developed to aid in the evaluation of watershed response to watershed management practices. The model has been applied worldwide and proven to be a very effective tool in identifying the critical areas which had serious erosion, and in aiding in decision-making processes for adopting BMPs and/or conservation programs so that cost/benefit can be maximized and non-point source pollution control can be achieved in the most efficient way. The main goal of this study was to assess the characteristics of soil erosion, sediment and sediment delivery of a watershed so that effective conservation measures can be implemented. To achieve the overall objective of this study, all necessary data for the 4,184 km2 Daning River watershed in the Three-Gorge region of the Yangtze River of China were assembled. The model was calibrated using observed monthly runoff from 1998 to 1999 (Nash-Sutcliffe coefficient of efficiency of 0.94 and R2 of 0.94) and validated using the observed monthly runoff from 2003 to 2005 (Nash-Sutcliffe coefficient of efficiency of 0.93 and R2 of 0.93). Additionally, the model was validated using annual average sediment of 2000–2002 (relative error of −0.34) and 2003–2004 (relative error of 0.18) at Wuxi station. Post validation simulation showed that approximately 48% of the watershed was under the soil loss tolerance released by the Ministry of Water Resources of China (500 t·km−2·y−1). However, 8% of the watershed had soil erosion of exceeding 5,000 t·km−2·y−1. Sloping areas and low coverage areas are the main source of soil loss in the watershed

    Polish School Nurses’ Attitudes and Knowledge towards Topical Fluoride Treatment

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    Cilj: Željelo se procijeniti mišljenje školskih medicinskih sestara u Poljskoj o topikalnoj primjeni fluorida te njihovo znanje o sigurnosti toga kemijskog spoja. Metoda: U presječnom istraživanju s pomoću anketnog upitnika sudjelovale su 164 školske medicinske sestre. Anketa je obuhvaćala raniju izobrazbu o prevenciji karijesa, mjere poduzete u školama kako bi se prevenirao karijes, suradnju s doktorima dentalne medicine, mišljenje o topikalnoj primjeni fluorida te znanja sestara o njihovoj sigurnosti. Rezultati: Oralno zdravlje bilo je uvršteno u dužnost 93,9 % sestara, a 81,7 % provodilo je lokalnu primjenu fluorida. U izobrazbi o oralnoj problematici nikada nije sudjelovalo njih 52,1 %. Sestre iz gradova češće su sudjelovale i održavale predavanja o prevenciji karijesa i o fluoridima od svojih kolegica u manjim gradovima (p = 0,033 i 0,021 – hi-kvadrat test). Sestre su imale pozitivno stajalište o učinkovitosti i sigurnosti topikalne primjene fluorida. Samo je polovina ispitanica znala za moguću toksičnu dozu, a jedna petina nije znala kolika je koncentracija fluora u gelu. Ta su znanja bila statistički važna, ovisno o razini izobrazbe pojedine sestre (p = 0,019 – Kruskal-Wallisov test). One s niskom razinom znanja nisu bile svjesne moguće štetnosti fluorida te su imale negativno stajalište o učinkovitosti programa fluoridacije u školama. Zaključak: Školske medicinske sestre u Poljskoj imale su pozitivno mišljenje o topikalnoj primjeni fluorida. No, ima manjkavosti u njihovu znanju pa im je potrebna institucionalizirana izobrazba.Aim: The aim of this study was to evaluate the Polish school nurses’ opinion on the topical fluoride treatment and their knowledge about fluoride safety. Material and methods: A cross-sectional study with the use of a self-administered questionnaire was conducted on 164 school nurses. The questionnaire concerned previous training in caries prevention, action taken at schools with regard to caries prevention, cooperation with dentists, opinion on the topical fluoride application program and nurses’ knowledge about fluoride safety. Results: 93.9% of nurses included oral health in their duties and 81.7% accomplished the topical fluoride treatment. 52.1% never attended any training concerning dental issues. Nurses from cities and villages more often than those from towns provided lectures on caries prevention and fluoride topical applications (respectively p= 0.033 and p=0.021, chi2 test). The nurses had a positive opinion on the effectiveness and safety of topical fluoride application. Only a half of respondents knew the fluoride probable toxic dose and one fifth of them did not know the concentration of fluoride in gel. The knowledge was statistically dependent on the level of nurses’ education (p=0.019, Kruskal-Wallis test). Nurses with a low level of knowledge were not aware of a potential harm effect of fluoride and they had negative opinion about the effectiveness of fluoride program at school. Conclusion: Polish school nurses had a positive opinion on topical fluoride treatment. However, there are gaps in their knowledge and the institutional training is needed

    A solid‐phase transfection platform for arrayed CRISPR screens [Corrigendum]

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    Since the publication of this study, it has come to our attention that a citation to the study by Bulkescher et al (2017) was omitted from the Introduction. The following sentence should have been included in the introduction: “A previously reported solid‐phase reverse transfection method for proteins (Bulkescher et al , 2017) was used for the delivery of RNPs for three endogenous genes suggesting the potential of solid‐phase reverse transfection for CRISPR/Cas9‐based gene editing, despite its low efficiency”. We apologise for any inconvenience this omission may have caused

    A solid-phase transfection platform for arrayed CRISPR screens

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    Arrayed CRISPR‐based screens emerge as a powerful alternative to pooled screens making it possible to investigate a wide range of cellular phenotypes that are typically not amenable to pooled screens. Here, we describe a solid‐phase transfection platform that enables CRISPR‐based genetic screens in arrayed format with flexible readouts. We demonstrate efficient gene knockout upon delivery of guide RNAs and Cas9/guide RNA ribonucleoprotein complexes into untransformed and cancer cell lines. In addition, we provide evidence that our platform can be easily adapted to high‐throughput screens and we use this approach to study oncogene addiction in tumor cells. Finally demonstrating that the human primary cells can also be edited using this method, we pave the way for rapid testing of potential targeted therapies

    Clinical characteristics in subjects with NLRP3 V198M diagnosed at a single UK center and a review of the literature

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    INTRODUCTION: Mutations in the NLRP3 gene are associated with the dominantly inherited cryopyrin-associated periodic syndrome (CAPS). The significance of the V198M variant is unclear; it has been reported in association with various CAPS phenotypes and as a variant of uncertain consequence. The aim of this study was to characterize the clinical phenotypes and treatments in individuals with V198M assessed in a single UK center. METHODS: DNA samples from 830 subjects with fever syndromes or a family history of CAPS were screened for mutations in the NLRP3 gene with polymerase chain reaction (PCR) and sequencing. A detailed medical history was available in all cases. Inflammatory disease activity was monitored monthly with measurements of serum amyloid A protein (SAA) and C-reactive protein (CRP) in symptomatic individuals. RESULTS: NLRP3 V198M was identified in 19 subjects. It was found in association with CAPS in five cases, in one patient with Schnitzler syndrome, in three patients who also had a nucleotide alteration in another fever gene, and in three other patients with evidence of an autoinflammatory phenotype. Seven asymptomatic individuals were detected during screening of family members. CONCLUSIONS: The NLRP3 V198M variant shows variable expressivity and reduced penetrance. It may be associated with classical inherited or apparently sporadic CAPS and with atypical autoinflammatory disease of varying severity, intriguingly including Schnitzler syndrome. The factors that influence the pathogenic consequences of this variant remain unknown. However, the remarkable response to interleukin 1 (IL-1) blockade in all but one individual in our series confirms that their clinical features are indeed mediated by IL-1
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