28 research outputs found
Finishing the euchromatic sequence of the human genome
The sequence of the human genome encodes the genetic instructions for human physiology, as well as rich information about human evolution. In 2001, the International Human Genome Sequencing Consortium reported a draft sequence of the euchromatic portion of the human genome. Since then, the international collaboration has worked to convert this draft into a genome sequence with high accuracy and nearly complete coverage. Here, we report the result of this finishing process. The current genome sequence (Build 35) contains 2.85 billion nucleotides interrupted by only 341 gaps. It covers ∼99% of the euchromatic genome and is accurate to an error rate of ∼1 event per 100,000 bases. Many of the remaining euchromatic gaps are associated with segmental duplications and will require focused work with new methods. The near-complete sequence, the first for a vertebrate, greatly improves the precision of biological analyses of the human genome including studies of gene number, birth and death. Notably, the human enome seems to encode only 20,000-25,000 protein-coding genes. The genome sequence reported here should serve as a firm foundation for biomedical research in the decades ahead
Formation of anodic TiO<sub>2</sub> nanotube arrays with bimodal pore size distribution
It is revealed that TiO2 nanotube arrays fabricated by anodization of the widely used polycrystalline hexagonal Ti foils have a bimodal pore size distribution rather than the commonly believed monomodal distribution manner. As characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM), it is shown that nanotubes grown on the Ti (0001) plane have thinner barrier thickness, smaller pore size, shorter tube length and better crystallinity than those grown on other planes, due to the enhanced electron transfer reaction and lower oxide formation efficiency on the Ti (0001) plane. When (0001) oriented Ti thin films deposited by RF magnetron sputtering are anodized, the pore sizes of the grown anodic TiO2 nanotubes distribute monomodally and are close to the smaller pore size of the bimodally distributed TiO2 nanotubes grown on polycrystalline Ti foils under the same conditions. Keywords: TiO2 nanotubes, Pore size distribution, Electrochemical anodization, Crystallographic orientatio
The role of the PM2.5-associated metals in pathogenesis of child Mycoplasma Pneumoniae infections:a systematic review
The peak occurrence of Mycoplasma pneumoniae (M. pneumoniae) infections in childhood and haze episodes is concurrent. Together, the prevalence of macrolide-resistant M. pneumoniae varies among countries might also be related to the concentration of ambient fine particulate mass (aerodynamic diameter a parts per thousand currency sign2.5 mu m, PM2.5). Numerous cohort studies have identified consistent associations between ambient PM2.5 and cardiorespiratory morbidity and mortality. PM2.5 is a carrier of the heavy metals. The relationship between PM2.5-associated metals and M. pneumoniae infections in childhood has been increasingly drawing public attention. First, we reviewed original articles and review papers in Pubmed and Web of Science regarding M. pneumoniae and PM2.5-associated metal and analyzed the structural basis of PM2.5-associated metal interaction with M. pneumoniae. Then, the possible mechanisms of action between them were conjectured. Mechanisms of oxidative stress induction and modulation of the host immune system and inflammatory responses via Toll-like receptors (TLRs) and/or the nuclear factor-kappa B (NF-kappa B) pathway are postulated to be the result of PM2.5-associated metal complex interaction with M. pneumoniae. In addition, a heavy metal effect on M. pneumoniae-expressed community-acquired respiratory distress syndrome (CARDS) toxin, and activation of the aryl hydrocarbon receptor (AhR) and TLRs to induce the differentiation of T helper (Th) cells are also regarded as important reasons for the influence of the heavy metals on the severity of M. pneumoniae pneumonia and the initial onset and exacerbation of M. pneumoniae associated asthma. PM2.5-associated metals via complex mechanisms can exert a great impact on the host through interaction with M. pneumoniae
Formation of anodic TiO<sub>2</sub> nanotube arrays with bimodal pore size distribution
It is revealed that TiO2 nanotube arrays fabricated by anodization of the widely used polycrystalline hexagonal Ti foils have a bimodal pore size distribution rather than the commonly believed monomodal distribution manner. As characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM), it is shown that nanotubes grown on the Ti (0001) plane have thinner barrier thickness, smaller pore size, shorter tube length and better crystallinity than those grown on other planes, due to the enhanced electron transfer reaction and lower oxide formation efficiency on the Ti (0001) plane. When (0001) oriented Ti thin films deposited by RF magnetron sputtering are anodized, the pore sizes of the grown anodic TiO2 nanotubes distribute monomodally and are close to the smaller pore size of the bimodally distributed TiO2 nanotubes grown on polycrystalline Ti foils under the same conditions. (c) 2013 Elsevier B.V. All rights reserved.</p
Study on the correlations between color rendering indices and the spectral power distribution
Natural Science Foundation of China [91022035, 51272282, 51302311]The intrinsic spectrally resolved sensitivity (ISRS) of color rendering indices (CRIs) is investigated by using spectral loss simulations. It is demonstrated that Ra exhibits large sensitivities around 444, 480, 564, and 622 nm, while for R-9 the sensitivity peaks are around 461, 581 and 630 nm, which all shift slightly with the correlated color temperature. If considering the ISRS as a bridge between the spectral power distribution of LED and its CRI, one could obtain a high CRI by minimizing the deviation between the shapes of the illuminant spectrum and the reference spectrum, both after modulations by the ISRS as a weighting function. This approach, recommended as a guideline for the spectra design aiming at a high CRI, is described and justified in depth via a mathematical model. This method is spectra-oriented and could largely facilitate the spectra design. (C)2014 Optical Society of Americ
Crust and upper mantle structures beneath Northeast China from receiver function studies
P-wave and S-wave receiver function analyses have been performed along a profile consisted of 27 broadband seismic stations to image the crustal and upper mantle discontinuities across Northeast China. The results show that the average Moho depth varies from about 37 km beneath the Daxing'anling orogenic belt in the west to about 33 km beneath the Songliao Basin, and to about 35 km beneath the Changbai mountain region in the east. Our results reveal that the Moho is generally flat beneath the Daxing'anling region and a remarkable Moho offset (about 4 km) exists beneath the basin-mountain boundary, the Daxing'anling-Taihang Gravity Line. Beneath the Tanlu faults zone, which seperates the Songliao Basin and Changbai region, the Moho is uplift and the crustal thickness changes rapidly. We interpret this feature as that the Tanlu faults might deeply penetrate into the upper mantle, and facilitate the mantle upwelling along the faults during the Cenozoic era. The average depth of the lithosphere-asthenosphere boundary (LAB) is ~80 km along the profile which is thinner than an average thickness of a continental lithosphere. The LAB shows an arc-like shape in the basin, with the shallowest part approximately beneath the center of the basin. The uplift LAB beneath the basin might be related to the extensive lithospheric stretching in the Mesozoic. In the mantle transition zone, a structurally complicated 660 km discontinuity with a maximum 35 km depression beneath the Changbai region is observed. The 35 km depression is roughly coincident with the location of the stagnant western pacific slab on top of the 660 km discontinuity revealed by the recent P wave tomography.11 page(s