Transparent polycrystalline ceramics have found various applications, such as laser hosts, infrared (IR) windows/domes, lamp envelopes and transparent armors, instead of their single crystal ...counterparts, due mainly to their processing flexibility in fabricating items with large sizes and complex shapes and more importantly cost-effectiveness. High optical transparent ceramics require high purity and high density. To achieve high purity final products, it is necessary to use high purity precursor powders. To get high density, various sintering technologies have been employed, such as high-pressure (HP) sintering, high isostatic pressure (HIP) sintering, vacuum sintering and spark plasma sintering (SPS). At the same time, various wet chemical synthesis routes have been used to produce precursor powders at submicron or even nanometer scales, with significantly improved sinterability. Transparent ceramics for armor and IR window/dome applications should have superior mechanical and thermal properties. Therefore, nanosized ceramics and nanocomposite ceramics have attracted much attention more recently. This review was aimed to summarize the latest progress in processing, materials and applications of transparent ceramics. It is arranged by starting with a brief introduction, followed by a detailed description on various sintering technologies used to develop transparent ceramics. After that, potential applications of transparent ceramics, together with their optical, mechanical and thermal properties, will be discussed. It will be concluded with discussions on future trend and perspectives, as well as some important issues, of transparent ceramic materials.
New iron selenide superconductors by intercalating smaller-sized alkali metals (Li, Na) and alkaline earths using high-temperature routes have been pursued ever since the discovery of ...superconductivity at about 30 K in KFe2 Se2 , but all have failed so far. Here we demonstrate that a series of superconductors with enhanced Tc = 30∼46 K can be obtained by intercalating metals, Li, Na, Ba, Sr, Ca, Yb, and Eu in between FeSe layers by the ammonothermal method at room temperature. Analysis on their powder X-ray diffraction patterns reveals that all the main phases can be indexed based on body-centered tetragonal lattices with a∼3.755-3.831 Å while c∼15.99-20.54 Å. Resistivities show the corresponding sharp transitions at 45 K and 39 K for NaFe2 Se2 and Ba0.8 Fe2 Se2 , respectively, confirming their bulk superconductivity. These findings provide a new starting point for studying the properties of these superconductors and an effective synthetic route for the exploration of new superconductors as well.
MaNGA (Mapping Nearby Galaxies at Apache Point Observatory) is a 6-yr Sloan Digital Sky Survey (SDSS-IV) survey that will obtain spatially resolved spectroscopy from 3600 to 10 300 Å for a ...representative sample of over 10 000 nearby galaxies. In this paper, we present the analysis of nebular emission-line properties using observations of 14 galaxies obtained with P-MaNGA, a prototype of the MaNGA instrument. By using spatially resolved diagnostic diagrams, we find extended star formation in galaxies that are centrally dominated by Seyfert/LINER-like emission, which illustrates that galaxy characterizations based on single fibre spectra are necessarily incomplete. We observe extended low ionization nuclear emission-line regions (LINER)-like emission (up to 1R
e) in the central regions of three galaxies. We make use of the Hα equivalent width EW(Hα) to argue that the observed emission is consistent with ionization from hot evolved stars. We derive stellar population indices and demonstrate a clear correlation between D
n(4000) and EW(HδA) and the position in the ionization diagnostic diagram: resolved galactic regions which are ionized by a Seyfert/LINER-like radiation field are also devoid of recent star formation and host older and/or more metal-rich stellar populations. We also detect extraplanar LINER-like emission in two highly inclined galaxies, and identify it with diffuse ionized gas. We investigate spatially resolved metallicities and find a positive correlation between metallicity and star formation rate surface density. We further study the relation between N/O versus O/H on resolved scales. We find that, at given N/O, regions within individual galaxies are spread towards lower metallicities, deviating from the sequence defined by galactic central regions as traced by Sloan 3-arcsec fibre spectra. We suggest that the observed dispersion can be a tracer for gas flows in galaxies: infalls of pristine gas and/or the effect of a galactic fountain.
We report the first results of a light weakly interacting massive particles (WIMPs) search from the CDEX-10 experiment with a 10 kg germanium detector array immersed in liquid nitrogen at the China ...Jinping Underground Laboratory with a physics data size of 102.8 kg day. At an analysis threshold of 160 eVee, improved limits of 8×10^{-42} and 3×10^{-36} cm^{2} at a 90% confidence level on spin-independent and spin-dependent WIMP-nucleon cross sections, respectively, at a WIMP mass (m_{χ}) of 5 GeV/c^{2} are achieved. The lower reach of m_{χ} is extended to 2 GeV/c^{2}.
We investigate collective emission from coherently driven ultracold (88)Sr atoms. We perform two sets of experiments using a strong and weak transition that are insensitive and sensitive, ...respectively, to atomic motion at 1 μK. We observe highly directional forward emission with a peak intensity that is enhanced, for the strong transition, by >10(3) compared with that in the transverse direction. This is accompanied by substantial broadening of spectral lines. For the weak transition, the forward enhancement is substantially reduced due to motion. Meanwhile, a density-dependent frequency shift of the weak transition (∼10% of the natural linewidth) is observed. In contrast, this shift is suppressed to <1% of the natural linewidth for the strong transition. Along the transverse direction, we observe strong polarization dependences of the fluorescence intensity and line broadening for both transitions. The measurements are reproduced with a theoretical model treating the atoms as coherent, interacting radiating dipoles.
In a base solution containing 10g/L sodium hydroxide and 12g/L phytic acid, the influence of sodium silicate concentration on the formation and properties of anodic coatings obtained by micro arc ...oxidation (MAO) on magnesium alloys was systematically studied. The results demonstrate that sodium silicate can increase the solution conductivity, decrease the final voltage and change the coating color. Amorphous magnesium silicate is detected and the silicon content in the coatings continually increases with the increasing of sodium silicate concentration. Silicate ions can simultaneously combine with magnesium and aluminum ions to develop anodic coatings, while phytic acid radicals preferentially react with magnesium ions. Sodium silicate can further improve the corrosion resistance of MAO treated magnesium and the coating shows the best corrosion resistance in the base solution with 10g/L sodium silicate.
► Sodium silicate can change the coating color. ► Silicate ions combine with magnesium and aluminum ions to develop anodic coatings. ► Sodium silicate competes with phytic acid for taking part in coating formation. ► Sodium silicate improves the corrosion resistance of MAO treated magnesium alloys.
Summary Background Previous estimates of the global burden of disease for children have not included much information from China, leading to a large gap in data. We identified the main causes of ...deaths in neonates (<1 month), postneonatal infants (1–11 months), and children (<5 years) in China using information that was available to the public. Methods The Child Health Epidemiology Reference Group in collaboration with colleagues from Peking University systematically searched Chinese databases that were available to the public. Information was obtained from the Chinese Ministry of Health and Bureau of Statistics websites, Chinese National Knowledge Infrastructure database, and Chinese Health Statistics yearbooks for 1990–2008. We also obtained information from 206 high-quality community-based longitudinal studies of different causes of deaths in children (<5 years) that were written in the Chinese language. A statistical model was developed to estimate the total number of deaths in children according to provinces, age groups, and main causes. Findings During 1990–2008, the mortality rates in neonates, postneonatal infants, and children were reduced by 70% (from 34·0 to 10·2 per 1000 livebirths), 72% (from 53·5 to 14·9 per 1000 livebirths), and 71% (from 64·6 to 18·5 per 1000 livebirths), respectively, meeting the targets set in the Millennium Development Goal 4. The leading causes of deaths in 2008 were pneumonia, birth asphyxia, and preterm birth complications, each accounting for 15–17% of all deaths. Congenital abnormalities and accidents increased in importance during this period, contributing to 11% and 10% of child deaths, respectively. Sudden infant death syndrome contributed to 5% of deaths in children. Interpretation Publically available Chinese databases contain much important information that has been underused in the estimation of global and regional burden of disease. On the basis of trends, preterm birth complications are expected to become the leading cause of child mortality in China, whereas deaths from congenital abnormalities, accidents, and sudden infant death syndrome are predicted to continue increasing in importance in the long term. Funding Bill & Melinda Gates Foundation.
Essentials Positive family histories suggest the existence of hereditary immune thrombocytopenia (ITP). The predisposing gene for familial ITP was screened in two familial ITP patients. The G76S ...mutation on TNFRSF13B led to immune dysfunction and induced megakaryocyte apoptosis. The G76S mutation on TNFRSF13B is a gain-of-function mutation and a predisposing variant for ITP.
Background Most immune thrombocytopenia (ITP) is sporadic but a positive family history of ITP in some patients suggests that hereditary forms exist. Because of the rarity of familial ITP families available for study and the heterogeneity of sporadic ITP, family linkage analysis or genome-wide association studies are limited. Objectives Based on one ITP pedigree, we try to identify the predisposing gene in familial or sporadic ITP and reveal the way in which it causes thrombocytopenia. Methods Gene expression profiling analysis and whole-exome sequencing were performed on samples from family members with ITP, sporadic ITP cases and healthy individuals. We also evaluated the influence of potential pathogenic mutation on immune function and megakaryocyte apoptosis. Results Whole-exome sequencing identified a potential pathologic p.G76S heterozygous mutation on the TNFRSF13B gene in familial ITP patients. ITP patients harboring the G76S mutation displayed an upregulated 'cytokine-cytokine receptor interaction' signal, increased serum TNFα, IL-17α, IFNγ and BAFF levels, and enhanced binding capacity of APRIL ligand to B cells. Additionally, Epstein-Barr virus (EBV)-transformed B cells with the G76S mutation could induce human megakaryocyte line (Meg-01) apoptosis significantly. Conclusion p.G76S mutation on the TNFRSF13B gene is responsible for ITP, and is a genetic predisposing factor for familial or sporadic ITP.
Summary
The domestic Asian water buffalo (Bubalus bubalis) is found on all five continents, with a global population of some 202 million. The livelihoods of more people depend on this species than on ...any other domestic animal. The two distinct types (river and swamp) descended from different wild Asian water buffalo (Bubalus arnee) populations that diverged some 900 kyr BP and then evolved in separate geographical regions. After domestication in the western region of the Indian subcontinent (ca. 6300 years BP), the river buffalo spread west as far as Egypt, the Balkans and Italy. Conversely, after domestication in the China/Indochina border region ca. 3000–7000 years BP, swamp buffaloes dispersed through south‐east Asia and China as far as the Yangtze River valley. Molecular and morphological evidence indicates that swamp buffalo populations have strong geographic genetic differentiation and a lack of gene flow, but strong phenotypic uniformity. In contrast, river buffalo populations show a weaker phylogeographic structure, but higher phenotypic diversity (i.e. many breeds). The recent availability of a high‐quality reference genome and of a medium‐density marker panel for genotyping has triggered a number of genome‐wide investigations on diversity, evolutionary history, production traits and functional elements. The growing molecular knowledge combined with breeding programmes should pave the way to improvements in production, environmental adaptation and disease resistance in water buffalo populations worldwide.
Single nucleotide polymorphisms (SNPs) near the IL28B gene have been shown to be associated with response to treatment for chronic hepatitis C and also with spontaneous clearance of hepatitis C virus ...(HCV) infection. We analysed the association between IL28B genetic variants and spontaneous clearance of HCV infection in 376 HCV‐infected Chinese paid plasma donors. Genotyping of eight SNPs near the IL28B region was performed by the iPLEX system (MassARRAY® SNP Genotyping; Sequenom) in all donors, and sequencing was performed on all 80 donors who cleared HCV and on 160 of 296 donors who did not clear HCV to validate the genotypes. Eighty (21.3%) donors spontaneously cleared HCV. Four SNPs were significantly associated with spontaneous HCV clearance: rs8099917 TT (vs GT), rs8105790 TT (vs CT), rs12980275 AA (vs AG) and rs10853728 CC (vs CG or GG) with OR (95% CI) 15.27 (2.07–112.50), 14.88 (2.02–109.72), 7.92 (1.88–33.32) and 2.32 (1.22–4.42) respectively. No association between the other four IL28B SNPs including rs12979860 and spontaneous HCV clearance was found. Women had a higher rate of spontaneous HCV clearance than men 56/213 (26.3%) vs 24/163 (14.6%), P = 0.007, and this was true even after stratification for IL28B genotypes with OR of 1.9–2.2 among those with favourable genotypes. Our results confirmed that IL28B polymorphism is associated with spontaneous clearance of HCV in Chinese subjects, but the SNPs that predict HCV clearance in Chinese subjects were different from those reported in Caucasians. Women were more likely to clear HCV infection regardless of IL28B genotypes.
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