Theoretical study of the influence of doped oxygen group elements on the properties of organic semiconductors

Organic semiconductor materials are widely used in the field of organic electronic devices due to their wide variety, low price, and light weight. However, their developments are still restrained by their low stability and carrier mobility. Density functional theory (DFT) was used to study the influence of doped oxygen group elements (O, S, Se, and Te) on the properties of organic semiconductor materials (seven-membered benzothiophene, o-pentacene, thiophene derivatives, and pentacene) in this paper. Based on the calculation of EHOMO, ELUMO, ΔE, and total energy, the performances of organic semiconductor materials without and with doped elements were compared, and it was found that the doping of multi-element Te makes the material have high stability and potential high mobility. For these studied organic semiconductor materials, when the atoms of the doped site change in the order of O, S, Se, and Te, the carrier mobility gradually increases, and the molecules show a tendency of stability. In this paper, promising doping elements and doping methods for these studied molecules are determined through calculations and screening out suitable materials more efficiently and economically without a large amount of repetitive experimental work, which may provide a theoretical basis and guidance for preparing high-performance organic semiconductor materials

HIV-1 can infect northern pig-tailed macaques (Macaca leonina) and form viral reservoirs in vivo

Viral reservoirs of HIV-1 are a major obstacle for curing AIDS. The novel animal models that can be directly infected with HIV-1 will contribute to develop effective strategies for eradicating infections. Here, we inoculated 4 northern pig-tailed macaques (NPM) with the HIV-1 strain HIV-1NL4.3 and monitored the infection for approximately 3 years (150 weeks). The HIV-1-infected NPMs showed transient viremia for about 10 weeks after infection. However, cell-associated proviral DNA and viral RNA persisted in the peripheral blood and lymphoid organs for about 3 years. Moreover, replication-competent HIV-1 could be successfully recovered from peripheral blood mononuclear cells (PBMCs) during long-term infection. The numbers of resting CD4+ T cells in HIV-1 infected NPMs harboring proviruses fell within a range of 2- to 3-log10 per million cells, and these proviruses could be reactivated both ex vivo and in vivo in response to co-stimulation with the latency-reversing agents JQ1 and prostratin. Our results suggested that NPMs can be infected with HIV-1 and a long-term viral reservoir was formed in NPMs, which might serve as a potential model for HIV-1 reservoir research

Thermal Environment Regulating Effects of Phase Change Material in Chinese Style Solar Greenhouse

AbstractPhase change material (PCM) can store and release heat within a certain temperature range during the phase transitions. Compared with sensible heat material, latent heat phase change material (PCM) is very attractive, because of its high-energy storage density and isothermal behavior during the phase change process. This paper attempts to research the application of PCM in Chinese style solar greenhouse. The PCM we used is butyl stearate with the phase change temperature about 18°C, and spinach of F1 from Italy is chosen to be the test plant. The research is a contrast test with the same two greenhouse models, one is installed with PCM and the other is not. By recording the temperature with T type thermocouples on the different set-points and observing the growth situation of the plants in two greenhouses, we can recognize the effect of the PCM on the thermal environment of greenhouse

Dual-Attention-Guided Multiscale Feature Aggregation Network for Remote Sensing Image Change Detection

Remote sensing image change detection plays an important role in urban planning and environmental monitoring. However, the existing change detection algorithms have limited ability in feature extraction, feature relationship understanding, and capture of small target features and edge detail features, which leads to the loss of some edge detail information and small target features. To this end, a new dual-attention-guided multiscale feature aggregation network is proposed. In the encoding stage, the fully convolutional dual-branch structure is used to extract the semantic features of different scales, and then, the multiscale adjacent semantic information aggregation module is used to aggregate the adjacent semantic features at different scales, which can better capture and fuse the features of different scales, thereby improving the accuracy and robustness of change detection. In the decoding stage, the dual-attention fusion module is proposed to guide and fuse the features extracted from different scales along the spatial and channel directions and reduce the background noise interference. In addition, this article also proposes a three-branch feature fusion module and a global semantic information enhancement module to make the network better integrate global semantics and differential semantics and further integrate high-level semantic features. We also introduce an auxiliary classifier in the decoding stage to provide additional supervision signals and fuse the output of the three auxiliary classifiers with the output of the main decoder to further achieve multiscale feature fusion. The comparative experiments on three remote sensing datasets show that the proposed method is superior to the existing change detection methods

Hot Deformation Behaviors of as Cast 321 Austenitic Stainless Steel

AISI 321 stainless steel has excellent resistance to intergranular corrosion and is generally used in nuclear power reactor vessels and other components. The as-cast and wrought structures are quite different in hot workability, so physical simulation, electron back-scatter diffraction, and hot processing maps were used to study the mechanical behavior and microstructure evolution of as-cast nuclear grade 321 stainless steel in the temperature range of 900–1200 °C and strain rate range of 0.01–10 s−1. The results showed that the flow curve presented work-hardening characteristics. The activation energy was calculated as 478 kJ/mol. The fraction of dynamic recrystallization (DRX) increased with increasing deformation temperature and decreasing strain rate. DRX grain size decreased with increasing Z value. Combining the hot working map and DRX state map, the suggested hot working window was 1000–1200 °C and 0.01–0.1 s−1. The main form of instability was necklace DRX. The nucleation mechanism of DRX was the migration of subgrains. The δ phase reduced the activation energy and promoted DRX nucleation of the tested steel

Developmental and metabolic responses of zebrafish (Danio rerio) embryos and larvae to short-chain chlorinated paraffins (SCCPs) exposure

Short-chain chlorinated paraffins (SCCPs) are highly toxic to aquatic organisms, but their toxicity is yet not well characterized. In this study, the developmental toxicity of SCCPs to zebrafish embryos/larvae was evaluated, and a metabolomics approach was adopted to explore the impact of SCCPs exposure on the metabolismin zebrafish embryos. Exposure to SCCPs at concentrations of 1-200 mu g/L did not produce an observable effect on the hatching rate andmorphological deformities of zebrafish embryos/ larvae. However, the survival rate of zebrafish larvae in SCCPs exposure groups decreased in a concentration-dependent manner. The 13-day 50% lethal concentration (LC50) value of SCCPs was calculated to be 34.4 mu g/L. Exposure to SCCPs induced a significant change of overall metabolism, even at environmentally relevant concentrations (1-5 mu g/L). The most relevant pathways affected by SCCPs exposure were glycerophospholipid metabolism, fatty acid metabolism and purine metabolism. Exposure to SCCPs at concentrations of 1-5 mu g/L had begun to accelerate the beta-oxidation of unsaturated fatty acids and very long chain fatty acids, and affect the transformation of guanine to xanthine in the pathway of purinemetabolism. Furthermore, when the exposure concentrations of SCCPs were increased to 50-200 mu g/L, the levels of phospholipids and amino acids were significantly raised; whereas the levels of fatty acids, carnitines and inosine were significantly decreased. In view of the significant effect on metabolism, the sub-chronic and chronic toxicity of SCCPs to fish should be concerned. (C) 2017 Elsevier B.V. All rights reserved

Toxicokinetics of short-chain chlorinated paraffins in Sprague-Dawley rats following single oral administration

Short-chain chlorinated paraffins (SCCPs) have attracted considerable attention for their characteristic of persistent organic pollutants. However, very limited information is available for their toxicokinetic characteristics, limiting the evaluation of their health risks. In this study, we performed a toxicokinetics study to explore the absorption and excretion processes of SCCPs (a mixture of C-10-, C-11-, C-12- and C-13- CPs) after a single oral administration to the Sprague Dawley rats. The toxicokinetic results showed that peak blood concentration of total SCCPs was attained at 2.8 day with C-max value of 2.3 mg L-1. The half-lives of total SCCPs in blood for the absorption t(1/2) (ka), distribution t(1/2) (alpha) and elimination phases t(1/2) (beta) were calculated to be 1.0,1.7 and 6.6 days, respectively. During the 28 days post-dosing, about 27.9% and 3.5% of orally administrated SCCPs were excreted through feces and urine without metabolism, respectively. Congener group abundance profiles indicate a relative increase of Cl-5-SCCPs in blood and urine in the elimination stage, and a higher accumulation of Cl8-10-SCCPs in feces. The distribution discrepancies of SCCPs congener groups in blood and excreta were more dependent on chlorine contents than on carbon chain lengths. (C) 2015 Elsevier Ltd. All rights reserved