Previous surveys on depression in China focused on prevalence estimates without providing a detailed epidemiological profile.
Face-to-face household interviews were conducted with a multi-stage ...household probability sample of 2633 adults (age > or = 18 years) in Beijing and 2568 in Shanghai between November 2001 and February 2002. The World Health Organization Composite International Diagnostic Interview (CIDI) was used to assess major depressive episode (MDE) according to Diagnostic and Statistical Manual of Mental Disorders (DSM)-IV criteria.
The lifetime prevalence and 1-year prevalence estimates of DSM-IV/CIDI MDE were 3.6% 95% confidence interval (CI) 2.8-4.4% and 1.8% (95% CI 1.2-2.4%) respectively. No significant gender difference was found in these estimates. Respondents born in 1967 or later were at elevated lifetime risk compared with respondents born in earlier cohorts. The mean age of onset was 30.3 years. Among those reporting 1-year MDE, 15.7, 51.8, 25.3 and 6.4% reported mild, moderate, severe and very severe symptoms respectively; 4.8, 2.6 and 3.2% reported suicidal ideation, plans, and recent attempts in the same year respectively. Respondents with 1-year MDE reported a mean of 27.5 days out of role owing to their depression in the year before interview. Significant co-morbidity was found between MDE and other mental disorders odds ratio (OR) 22.0 and chronic physical disorders (OR 3.2). Only 22.7% of respondents with 1-year MDE sought treatment.
The low prevalence and insignificant gender difference, but not patterns of onset, course, co-morbidity, and impairment, distinguish the epidemiological profile of MDE in metropolitan China from those in other countries.
Time-resolved sum-frequency vibrational spectroscopy permits the study of hitherto neglected ultrafast vibrational dynamics of neat water interfaces. Measurements on interfacial bonded OH stretch ...modes revealed relaxation behavior on sub-picosecond time scales in close resemblance to that of bulk water. Vibrational excitation is followed by spectral diffusion, vibrational relaxation, and thermalization in the hydrogen-bonding network. Dephasing of the excitation occurs in <=100 femtoseconds. Population relaxation of the dangling OH stretch was found to have a time constant of 1.3 picoseconds, the same as that for excitation transfer between hydrogen-bonded and unbonded OH stretches of water molecules surrounded by acetone.
Gate-Variable Optical Transitions in Graphene Wang, Feng; Zhang, Yuanbo; Tian, Chuanshan ...
Science (American Association for the Advancement of Science),
04/2008, Letnik:
320, Številka:
5873
Journal Article
Recenzirano
Two-dimensional graphene monolayers and bilayers exhibit fascinating electrical transport behaviors. Using infrared spectroscopy, we find that they also have strong interband transitions and that ...their optical transitions can be substantially modified through electrical gating, much like electrical transport in field-effect transistors. This gate dependence of interband transitions adds a valuable dimension for optically probing graphene band structure. For a graphene monolayer, it yields directly the linear band dispersion of Dirac fermions, whereas in a bilayer, it reveals a dominating van Hove singularity arising from interlayer coupling. The strong and layer-dependent optical transitions of graphene and the tunability by simple electrical gating hold promise for new applications in infrared optics and optoelectronics.
Objectives The purpose of this study was to compare the efficiency, cost, and safety of a diagnostic strategy employing early coronary computed tomographic angiography (CCTA) to a strategy employing ...rest-stress myocardial perfusion imaging (MPI) in the evaluation of acute low-risk chest pain. Background In the United States, >8 million patients require emergency department evaluation for acute chest pain annually at an estimated diagnostic cost of >$10 billion. Methods This multicenter, randomized clinical trial in 16 emergency departments ran between June 2007 and November 2008. Patients were randomly allocated to CCTA (n = 361) or MPI (n = 338) as the index noninvasive test. The primary outcome was time to diagnosis; the secondary outcomes were emergency department costs of care and safety, defined as freedom from major adverse cardiac events in patients with normal index tests, including 6-month follow-up. Results The CCTA resulted in a 54% reduction in time to diagnosis compared with MPI (median 2.9 h 25th to 75th percentile: 2.1 to 4.0 h vs. 6.3 h 25th to 75th percentile: 4.2 to 19.0 h, p < 0.0001). Costs of care were 38% lower compared with standard (median $2,137 25th to 75th percentile: $1,660 to $3,077 vs. $3,458 25th to 75th percentile: $2,900 to $4,297, p < 0.0001). The diagnostic strategies had no difference in major adverse cardiac events after normal index testing (0.8% in the CCTA arm vs. 0.4% in the MPI arm, p = 0.29). Conclusions In emergency department acute, low-risk chest pain patients, the use of CCTA results in more rapid and cost-efficient safe diagnosis than rest-stress MPI. Further studies comparing CCTA to other diagnostic strategies are needed to optimize evaluation of specific patient subsets. (Coronary Computed Tomographic Angiography for Systematic Triage of Acute Chest Pain Patients to Treatment CT-STAT; NCT00468325 )
With a suite of multi-modal and multi-scale characterization techniques, the present study unambiguously proves that a substantially-improved combination of ultrahigh strength and good ductility can ...be achieved by tailoring the volume fraction, morphology, and carbon content of the retained austenite (RA) in a transformation-induced-plasticity (TRIP) steel with the nominal chemical composition of 0.19C–0.30Si–1.76Mn–1.52Al (weight percent, wt%). After intercritical annealing and bainitic holding, a combination of ultimate tensile strength (UTS) of 1100MPa and true strain of 50% has been obtained, as a result of the ultrafine RA lamellae, which are alternately arranged in the bainitic ferrite around junction regions of ferrite grains. For reference, specimens with a blocky RA, prepared without the bainitic holding, yield a low ductility (35%) and a low UTS (800MPa). The volume fraction, morphology, and carbon content of RA have been characterized using various techniques, including the magnetic probing, scanning electron microscopy (SEM), electron-backscatter-diffraction (EBSD), and transmission electron microscopy (TEM). Interrupted tensile tests, mapped using EBSD in conjunction with the kernel average misorientation (KAM) analysis, reveal that the lamellar RA is the governing microstructure component responsible for the higher mechanical stability, compared to the blocky one. By coupling these various techniques, we quantitatively demonstrate that in addition to the RA volume fraction, its morphology and carbon content are equally important in optimizing the strength and ductility of TRIP-assisted steels.
This study concerns the employment of instrumented indentation to characterize the power-law creep response of metallic materials. Systematic numerical finite element analyses of conical indentation, ...under controlled constant indentation strain rates, were conducted. The model system is pure tin (Sn) and Sn-based alloy with known uniaxial power-law creep parameters, with their stress exponents ranging from 7 to 10. It was found that the constant indentation strain rate results in a steady-state hardness which is independent of indentation depth. The indentation-derived stress exponents are almost identical to those of uniaxial creep, leading to parallel lines of strain rate versus creep stress on the logarithmic scale. A remarkably consistent ratio of uniaxial strain rate and indentation strain rate, 0.33, was obtained for all the model materials considered.
We characterize one transcription factor of DRE-binding proteins (TaDREB1) that was isolated from a drought-induced cDNA library of wheat (Triticum aestivum L.). TaDREB1 contains one conserved ...EREBP/AP2 domain, and shows similarity with Arabidopsis thaliana DREB family members in both overall amino-acid sequences and the secondary structure arrangement within the DNA-binding motifs. In yeast one-hybrid system, TaDREB1, can specially activate the genes fused with the promoter containing three tandemly repeated copies of the wild-type DRE sequence: TACCGACAT. In different wheat cultivars, the Ta DREB1 gene is induced by low temperature, salinity and drought; and the expression of Wcs120 that contains DRE motifs in its promoter is closely related to the expression of TaDREB1. These results suggest that TaDREB1 functions as a DRE-binding transcription factor in wheat. We also observed the dwarf phenotype in transgenic rice (T0) overexpressing TaDREB1.
Abstract
Einstein–Podolsky–Rosen (EPR) steering is a quantum effect based on quantum entanglement and it is the key resource for building quantum networks because of its useful properties. Based on ...the criterion for genuine multipartite EPR steering, the genuine quadripartite EPR steering is confirmed and it can be generated by a spontaneous parametric down-conversion cascaded process with two sum-frequency generations in an optical superlattice. This occurs either below the oscillation threshold and without oscillation threshold. The influence of the parameters of cascaded nonlinear process on the quadripartite EPR steering among signal, idler, and two sum-frequency beams are also discussed. Choosing appropriate nonlinear parameters can achieve good quadripartite quantum steering. This scheme of the generation of genuine quadripartite EPR steering has potential applications in quantum communication and computing.
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