Search

We report the studies of structure and properties of a quasi-one-dimensional (quasi-1D) compound ${\rm BaTiS}_{3}$ BaTiS 3 under pressure. The poly-crystalline samples are synthesized by solid-state reaction method and single-crystalline samples are produced by chemical vapor transport method. The XRD measurement under ambient pressure confirms the hexagonal structure, which consists of face-sharing octahedral ${\rm TiS}_{6}$ TiS 6 chains along c-axis and displays a quasi-1D feature. When applying pressure, the synchrotron X-ray diffraction experiments show that the sample undergoes a phase transition from hexagonal phase to orthorhombic phase at around 10 GPa due to the zig–zag deformation of ${\rm TiS}_{6}$ TiS 6 chains, while the quasi-1D structure is reserved. At ambient pressure, ${\rm BaTiS}_{3}$ BaTiS 3 exhibits an insulating behavior with a band gap about 0.273 eV. When applying pressure, the sample undergoes a crossover from insulator to metal due to the enhancement of inter-chain electron hopping. [ABSTRACT FROM AUTHOR]

The dependence of thermoluminescence (TL) and optically stimulated luminescence (OSL) properties of LiMgPO4:Tb,Sm,B samples prepared by the high-temperature solid-state method on maximum heating temperatures was investigated for the first time. The TL glow curves showed the ratio of peak 3 to peak 2 increased with the increase of maximum heating temperature. The influence of OSL on maximum heating temperatures showed that the sensitivity of OSL reached the maximum at the maximum heating temperature of 1000°C, which is 11.6 times higher than that of 800 °C. The relative standard deviation of the repeatability is less than 1.5% regardless of the maximum heating temperature. The minimum measurable dose (MMD) could be significantly improved by optimizing OSL parameters, such as maximum heating temperature and readout time. The MMD as low as 0.31 µGy has been achieved. The residual OSL is up to 92.3% after irradiation for 24 h. LiMgPO4:Tb,Sm,B is highly sensitive to the maximum heating temperature. Considering fast decay time, high OSL sensitivity, good repeatability, low MMD and little fading, it is recommended that the maximum heating temperature of LiMgPO4:Tb,Sm,B is 1000°C. LiMgPO4:Tb,Sm,B has great potential for daily personal and environmental cumulative dose monitoring. [ABSTRACT FROM AUTHOR]

In this paper, we propose a penalized weighted quantile estimating equations (PWQEEs) method to obtain sparse, robust and efficient estimators for the quantile regression with longitudinal data. The PWQEE incorporates the within correlations in the longitudinal data by Gaussian copulas and can also down-weight the high leverage points in covariates to achieve double-robustness to both the non-normal distributed errors and the contaminated covariates. To overcome the obstacles of discontinuity of the PWQEE and nonconvex optimization, a local distribution smoothing method and the minimization–maximization algorithm are proposed. The asymptotic properties of the proposed method are also proved. Furthermore, finite sample performance of the PWQEE is illustrated by simulation studies and a real-data example. [ABSTRACT FROM AUTHOR]

The generalized estimating equations (GEE) method has been widely used for longitudinal data analysis. Wang [GEE analysis of clustered binary data with diverging number of covariates. Ann Stat. 2011;39:389–417] developed an asymptotic theory for GEE analysis of clustered binary data with diverging number of covariates. She suggested several moment estimators of the nuisance parameter in the working correlation matrix. However, these estimators might not exist when the working correlation structure is misspecified. When the number of covariates is finite, Xu et al. [A finite mixture model for working correlation matrices in generalized estimating equations. Stat Sin. 2012;22:755–776] proposed a mix-GEE method based on a finite mixture model to capture correlations among repeated measurements. In this paper, we develop an asymptotic theory for the mix-GEE estimator with diverging number of covariates. Simulation studies are used to demonstrate the performance of the mix-GEE with diverging number of covariates, which indicate this method is more numerically stable and has a higher efficiency than the GEE with a specified working correlation matrix in diverging number of covariates framework. Finally, a real dataset is used for illustration. [ABSTRACT FROM AUTHOR]

In this study, Ti6Al7Nb alloy produced by twin-wire arc additive manufacturing was oxidized at 800°C to identify the oxidation difference induced by heat-affected bands (HABs), which have been widely reported in additive manufactured titanium alloys. The oxidation kinetics proved that HABs with compact β laths have stronger oxidation resistance compared with that of the non-HAB zone. Nb element enriched in β phase promoted Ti3Al to precipitate at the original position of β laths after oxidation, having a similar spacing to the β laths. The formation of compact Ti3Al on HAB beneficially inhibits oxygen diffusion across the oxide scale/matrix interface. Oxidation difference induced by microstructural bands in additive manufactured titanium alloy was identified, and the stronger oxidation resistance of heat-affected bands was attributed to the more compact β laths. [ABSTRACT FROM AUTHOR]

The Huanghua Depression is a complex secondary tectonic unit in the Bohai Bay Basin of eastern China. This work analyses the geometric features and formation mechanisms of Mesozoic compressional structures developed within the Huanghua Depression. Compressional deformation has formed open-fold, single reverse or thrust faulting, duplex structures and imbricated structures that can be divided into two dominating groups by their distribution direction: nearly E–W- and WNW-directed and NNE- and NE-directed. There are three phases of Mesozoic compression: Late Triassic, Late Jurassic–earliest Early Cretaceous and Late Cretaceous. The Late Triassic compressional structures were formed by near N–S- and NNE-directed compressional stress whereas late Jurassic–earliest Early Cretaceous and Late Cretaceous compressional structures were formed by a WNW-directed compressional stress field. The three phases of Mesozoic compression in the Huanghua Depression are consistent with the evolution of the regional tectonic setting, in particular the interaction mode and timing of the North China Block with surrounding plates. Compressional deformation in the Huanghua Depression can be divided into two dominating groups by their distribution direction: nearly E–W- and WNW-directed and NNE- and NE-directed. There are three phases of Mesozoic compression: Late Triassic, Late Jurassic–earliest Early Cretaceous and Late Cretaceous. The three phases of Mesozoic compressional structures in the Huanghua Depression are consistent with the evolution of the regional tectonic setting. [ABSTRACT FROM AUTHOR]

Purpose: Cytomegalovirus retinitis (CMVR) is a serious and potentially sight-threatening infection in immunocompromised individuals. Strategies for the management of drug-resistant CMVR are described. Methods: A case of severe bilateral CMVR in a single lung transplant patient, with UL97 mutation conferring ganciclovir-resistance, is presented. Treatment with standard antiviral agent and adjuvant leflunomide, immunosuppression modifications (calcineurin inhibitors and corticosteroid), intravitreal antiviral therapy and novel use of CMV-immunoglobulin is described. A literature review to support drug-resistant CMVR management is presented. Results: Severe and progressive CMV retinitis was refractory to intravitreal foscarnet and systemic leflunomide. Drug-toxicity restricted systemic antiviral therapy options. The use of combined leflunomide and CMV-immunoglobulins, in the absence of viremia, has not been previously reported. Loss of ganciclovir-resistance was eventually observed permitting successful treatment with systemic and intravitreal ganciclovir. Conclusions: Drug-resistant CMVR is a complex clinical challenge. Multiple systemic and local treatment strategies may be necessary but toxicity, resistance, and co-morbidities may severely restrict available options. [ABSTRACT FROM AUTHOR]

This paper addresses the job shop-scheduling problem with minimizing the number of tardy jobs as the objective. This problem is usually treated as a job-sequencing problem, and the permutation-based representation of solutions was commonly used in the existing search-based approaches. In this paper, the flaw of the permutation-based representation is discussed, and a rule-centric concept is proposed to deal with it. A memetic algorithm is then developed to realize the proposed idea by tailored genome encoding/decoding schemes and a local search procedure. Two benchmark approaches, a multi-start hill-climbing approach and a simulated annealing approach, are compared in the experiments. The results show that the proposed approach significantly outperforms the benchmarks. [ABSTRACT FROM AUTHOR]

This paper addresses the scheduling problem in the wafer probe centre. The proposed approach is based on the dispatching rule, which is popularly used in the semiconductor manufacturing industry. Instead of designing new rules, this paper proposes a new paradigm to utilize these rules. The proposed paradigm formulates the dispatching process as a 2-D assignment problem with the consideration of information from multiple lots and multiple pieces of equipment in an integrated manner. Then, the dispatching decisions are made by maximizing the gains of multiple possible decisions simultaneously. Besides, we develop a genetic algorithm (GA) for generating good dispatching rules through combining multiple rules with linear weighted summation. The benefits of the proposed paradigm and GA are verified with a comprehensive simulation study on three due-date-based performance measures. The experimental results show that under the proposed paradigm, the dispatching rules and GA can perform much better than under the traditional paradigm. [ABSTRACT FROM AUTHOR]

This paper addresses the job shop-scheduling problem with due date-based objectives including the tardy rate, mean tardiness and maximum tardiness. The focused approach is the dispatching rules. Eighteen dispatching rules are selected from the literature, and their features and design concepts are discussed. Then a dispatching rule is proposed with the goal of achieving a good and balanced performance when more than one objective is concerned at the same time. First, three good design principles are recognized from the existing rules. Second, it introduces a due date extension procedure to solve a problem of negative allowance time. Third, a job candidate reduction mechanism is developed to make the rule computationally efficient. Lastly, a comprehensive simulation study is conducted with the 18 existing rules as the benchmarks. The experimental results verify the superiority of the proposed rule, especially on the tardy rate and mean tardiness. [ABSTRACT FROM AUTHOR]

Introduction:Some studies of Posttraumatic Stress Disorder (PTSD) find executive dysfunction, whereas others do not. We meta-analytically examined the association between executive function and PTSD and used meta-regression to examine the potential moderating effect of PTSD severity on executive function. Methods:We conducted a meta-analysis according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. We identified published peer-reviewed articles containing measures of executive function and PTSD symptom severity in subjects with PTSD compared to trauma-unexposed controls or trauma-exposed controls without PTSD, or both. We calculated an effect size for each study containing at least one measure of executive function and PTSD symptom severity. Results:PTSD subjects for whom the Clinician-Administered PTSD Scale (CAPS) score was available had worse executive function compared to both trauma-unexposed controls (g = 0.464,p < .001) and to trauma-exposed controls without PTSD (g = 0.414,p = .001), as did PTSD subjects for whom the Mississippi Scale for Combat-Related PTSD (M-PTSD) score was available (g = 0.390,p < .001). Neither CAPS nor M-PTSD scores significantly moderated the effect size of executive function. Conclusions:PTSD is associated with executive dysfunction, but this association was not moderated by PTSD symptom severity, suggesting that once PTSD occurs, executive dysfunction may occur regardless of PTSD severity. [ABSTRACT FROM PUBLISHER]

In this study, we retrieved a series of 59 dihydroalkylthio-benzyloxopyrimidine (S-DABO) derivatives, which is a class of highly potent HIV-1 non-nucleoside reverse transcriptase inhibitors (NNRTIs) reported from published articles, and analysed them with comparative molecular field analysis (CoMFA) and comparative molecular similarity indices analysis (CoMSIA). Statistically significant three-dimensional quantitative structure–activity relationship (3D-QSAR) models by CoMFA and CoMSIA were derived from a training set of 46 compounds on the basis of the rigid body alignment. Further, the predictive ability of the QSAR models was validated by a test set of 13 compounds. Based on the information derived from CoMFA and CoMSIA contour maps, we have identified some steric and electrostatic features for improving the activities of these inhibitors, and we validated the 3D-QSAR results by a molecular docking method. On the basis of the obtained results, we designed a new series ofS-DABO derivatives with high activities. Therefore, this study could be utilized to design more potentS-DABO analogues as anti-HIV agents. [ABSTRACT FROM PUBLISHER]

Fine-grained AISI 4140 steel with ultra-high strength and substantial ductility are obtained by combining warming rolling (WR) and cyclic quenching (CQ). The prior austenite grain size of WR+CQ processed steel is about 5·5 μm, as compared to 12·4 μm for the direct quenching (DQ) processed steel. The microhardness of DQ processed steel and WR+CQ processed steel are similar and fluctuate around HV 610 even further cycles of CQ process are given. The yield strength (YS), ultimate tensile strength (UTS) and percentage elongation after fracture (EL) of WR+one-cycle-CQ are 1943 MPa, 2286 MPa and 8·47%, respectively, indicating the potential of WR+CQ process to produce ultra-high strength steel with WR+CQ is an effective way to develop ultra-high strength steels with substantial ductility. [ABSTRACT FROM AUTHOR]

Objectives: Multiple methods of selective brain cooling have been used to prevent cerebral ischemia secondary to trauma and pathological or iatrogenic cerebral blood flow restriction. In this study, we tested the efficacy of hypothermic retrograde jugular vein flush (HRJVF) in eliciting selective brain hypothermia in a porcine model. Methods: Twelve swine were divided into two groups: retrograde jugular vein infusion (RJVI) with cold saline (4°C RJVI, n = 6) and with room temperature saline (24°C RJVI, n = 6). For 90 minutes, the following parameters were measured: brain parenchymal temperature, rectal temperature, intracranial pressure (ICP), mean arterial pressure, and heart rate (HR). Results: Swine receiving 4°C RJVI experienced a drop in mean brain parenchymal temperature of 1.1 ± 0.1°C, compared to 0.1 ± 0.1°C in swine receiving 24°C RJVI. At 90 minutes, mean brain parenchymal temperature in the 4°C RJVI treatment group was 35.5 ± 0.2°C, as compared to 37.1± 0.2°C in the 24°C RJVI treatment group (P< 0.001). In the 4°C RJVI group, the brain-systemic temperature gradient peaked 10 minutes after initiation of cooling and remained significantly different when comparing the two experimental groups (P < 0.001) throughout the duration of the 90 minutes experiment. Of note, ICP, mean arterial pressure, and HR remained constant without any significant changes or differences between treatment groups. Discussion: These results suggest that HRJVF is an effective method for selective brain hypothermia in a large animal model. Clinical application may prove effective in delaying neural ischemia. [ABSTRACT FROM AUTHOR]

It is desirable that wear testing results obtained using different techniques can be mutually converted. In this study, wear rates of two groups of materials, i.e. cast iron and steel, were evaluated using the ASTM G65 dry sand rubber wheel abrasion and pin-on-disc wear testers respectively. The conversion between results obtained using the two different methods was investigated. It was shown that the two sets of wear data can be mutually converted, following a linear relation. The slope and position of the line that fits the data are, however, affected by Young's modulus of the materials and the applied load. Such effects are attributed to the fact that the wear rate of the materials measured using the G65 method was influenced by not only hardness but also elastic modulus, while for the pin-on-disc tests, the wear rate was more dominated by hardness of the target materials especially under larger applied loads. Relevant mechanisms are discussed with a further look at the Archard's wear equation. [ABSTRACT FROM AUTHOR]

An analytical method using sector field inductively coupled plasma mass spectrometry (SF-ICP-MS) for rapid simultaneous determination of Na, Mg, K, Ca, Cr, Mn, Fe, Co, Ni, Cu, Zn, Se, Sr, Mo, and Cd elements in hepatocellular carcinoma (HCC) tissue is reported. The sample was dissolved in HNO3and H2O2by microwave digestion and then the aforementioned 15 elements in the solution were analyzed directly by SF-ICP-MS. Most of the spectral interferences were avoided by measuring in medium resolution mode (MRM, M/▵M = 4400) and high resolution mode (HRM, M/ΔM = 8000). Correction for matrix effects was made using Sc and Rh as internal standards. The optimum conditions for the determination were tested and discussed. The results showed that SF-ICP-MS is a useful tool for simultaneous determination of multi-elements in HCC tissue and could be widely used in other biological samples analysis. [ABSTRACT FROM AUTHOR]

A toxicity data set containing the toxicities of 970 hydrophobic, polar and ionizable, nitro substituted and α,β-unsaturated compounds to Tetrahymena pyriformis was classified into different groups based on the structure and substituted functional groups. Polar, ionizable and reactive compounds exhibit greater toxicity as compared with the non-polar hydrophobic compounds. Step-by-step analysis was carried out between the toxicity and descriptors representing hydrophobicity, polarity/polarizability, ionization and reactivity of compounds. Significant relationships were developed between the toxicity and these descriptors for the compounds. The models developed are simple, interpretable and transparent, using a small number of descriptors that may reflect the interactions of chemicals with the biological macromolecules at the target sites. Hydrophobic parameter log P reflects bio-uptake process compounds. Polarity/polarizability descriptor S reflects the interaction of hydrophilic residues of polar chemicals with biological macromolecules. The fractions of ionized (F i) and neutral (F 0) forms calculated from pK a reflect the interactions of ionizable compounds with the macromolecules and effect of ionization of ionizable compounds on the bio-uptake process, respectively. A successful single model was developed by using the descriptors log P, S, F i and log F 0 for non-polar, polar and ionizable compounds. [ABSTRACT FROM AUTHOR]

The relationship between log K oc and log P was examined by use of a large dataset. For most of the hydrophobic compounds (e.g. 0.5 < log P < 7.5), the organic carbon content plays a dominant role in soil sorption and the sorption coefficient is linearly related to the octanol/water partition coefficient. For hydrophilic compounds (e.g. log P < 0.5), hydrophobic sorption becomes less significant. The hydrophilic contribution to sorption is equal to, or higher than, the hydrophobic contribution to sorption, resulting in the observed K oc values being higher than those predicted from their log P values. For highly hydrophobic compounds (e.g. log P > 7.5), log K oc decreases with increasing hydrophobicity because of a lack of chemical availability due to low solubility. A linear solvation energy relationship shows that the sorption potential increases with increasing molecular size by increasing the dispersion interactions between the chemical and soil organic phase. The sorption potential decreases with increase in the basicity of hydrophobic compounds by increasing the H-bonding of chemicals with water. Principal component analysis shows that the octanol/water system is the closest system, but not an ideal surrogate, to describe the soil sorption for hydrophobic compounds as compared with other solvent/water partition systems. [ABSTRACT FROM AUTHOR]

A wireless sensor system powered by AM broadcast energy harvesting is presented. A 10 meter length horizontal antenna and a resonant circuit were combined to harvest the electromagnetic energy, in the frequency range from 531 kHz to 1602 kHz. In a typical urban environment, an output voltage up to 14 V and a power of 82 μ W were obtained by a single stage doubler rectifier. A seven-day measurement is implemented to verify the stability of the energy. The output characteristics, multi stage doubler rectifier and implementation of sensor prototype are also discussed. The results indicate that the energy carried by AM radio is sufficient to drive a basic wireless sensor operating in sleep/wakeup mode. The stability and continuity of the harvested energy is superior to solar energy. [ABSTRACT FROM AUTHOR]

On June 20, 2008, Jason-2 was successfully launched by a Boeing Delta II rocket from the Vandenberg site, California. The OSTM/Jason-2 project is a cooperation among NASA, NOAA, EUMETSAT, and CNES. The first two months of the OSTM/Jason-2 mission have been dedicated to the assessment of the overall system. The goal of this assessment phase was: to assess the behavior of the spacecraft, at the platform and payload levels; to verify that platform performance requirements are met with respect to Jason-2 requirements; to verify that payload instruments performance requirements evaluated at instrument level are met; and to assess the performance of the Jason-2 Ground System. The paper will display the main outputs of the assessment of the system. It will demonstrate that all the elements of the onboard and ground systems are within the specifications. [ABSTRACT FROM AUTHOR]

On 7 December 2001, Jason-1 was successfully launched by a Boeing Delta II rocket from the Vandenberg Air Force Base, California. The Jason-1 satellite will maintain the high accuracy altimeter service provided since 1992 by TOPEX/Poseidon (T/P), ensuring the continuity in observing and monitoring the Ocean Dynamics (intraseasonal to interannual changes, mean sea level, tides, etc.). Despite one-fourth the mass and power, the Jason-1 system has been designed to have basically the same performance as T/P, measuring sea surface topography at a centimetric level. This new CNES/NASA mission also provides near real-time data for sea state and ocean forecast. The first two months of the Jason-1 mission have been dedicated to the assessment of the overall system. The goals of this assessment phase were: 1. To assess the behavior of the spacecraft at the platform and payload levels (Jason-1 being the first program to call on the PROTEUS versatile multimission platform for Low and Medium Earth Orbit Missions developed in partnership between Alcatel Space and CNES); 2. To verify that platform performance requirements are met with respect to Jason-1 requirements; 3. To verify that payload instruments performance requirements evaluated at instrument level are met; 4. To assess the performance of the Jason-1 Ground System. This article will display the main outputs of the assessment of the system. It will demonstrate that all the elements of the onboard and ground systems are within the specifications. Provision of data to the Jason-1 Science Working Team started at the end of March 2002. This is the goal of a six-month phase after closure of the initial assessment phase to derive the error budget of the system in terms of altimetry user products. [ABSTRACT FROM AUTHOR]

For different levels of user performance, different types of information are processed and users will make different types of errors. Based on the error's immediate cause and the information being processed, usability problems can be classified into three categories. They are usability problems associated with skill-based, rule-based and knowledge-based levels of performance. In this paper, a user interface for a Web-based software program was evaluated with two usability evaluation methods, user testing and heuristic evaluation. The experiment discovered that the heuristic evaluation with human factor experts is more effective than user testing in identifying usability problems associated with skill-based and rule-based levels of performance. User testing is more effective than heuristic evaluation in finding usability problems associated with the knowledge-based level of performance. The practical application of this research is also discussed in the paper. [ABSTRACT FROM AUTHOR]

AbstractNanoparticle profile control agents have been widely used for water shut-off treatment due to their excellent properties. However, the contradiction between the injectability and the plugging characteristics of profile control agents seriously affects their sealing effect. Self-aggregating nanoparticles can effectively alleviate this contradiction by forming particle clusters in the formation to block water channels. In this study, the injection and plugging properties of self-aggregating nanoparticle profile control agents in porous media were investigated using visual porous media etching model and core model. Injectivity experiments showed that the flow of nanoparticles in porous media was divided into three phases: flow dispersion phase, self-aggregation migration phase, and aggregation plugging state. They could aggregate to form clusters similar to the pore throat size after 60 min. Core displacement experiments showed that the plugging performance of nanoparticles was influenced by solution concentration, injection volume, injection rate, and core permeability. When injecting a 3000 mg/L nanoparticle solution into the core at 60 °C, the residual resistance coefficient was larger than 1.83. The retention rate in pore throats was superior to 60%. [ABSTRACT FROM AUTHOR]

The article presents a case study of a 23-year-old married woman diagnosed with cerebral venous thrombosis and thromboembolic stroke caused by Ovarian Hyperstimulation Syndrome (OHSS). Topics discussed include the medical history and records of the patient, her physical examination, an overview of OHSS, its diagnosis, risk factors and its treatment.