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The reaction of diorganyl disulfides or diselenides with PhICl2 in acetonitrile was found for the first time to lead to the in situ formation of organosulfenyl chloride or selenenyl chloride, which enables the regioselective intramolecular chalcogenylacyloxylation of alkynes resulting in the formation of 4-chalcogenylisocumarins/pyrones in good to excellent yields under metal-free conditions.

The influence of terminal hydrophobe branching on the micellar properties of Hydrophobically modified Ethoxylated URethanes (HEURs) is addressed through fluorescence, dynamic light scattering (DLS), solution rheology, and Raman spectroscopy. Model HEURs used in this study are monodisperse and fully substituted with hydrophobic groups of different structures. Two linear hydrophobes (l-C12H25 and l-C16H33) and three branched hydrophobes [b-(C12H26), b-(C16H34), and b-(C20H42)]are coupled to the hydroxyls of POE670 and POE195 through 4,4-methylene bis(dicyclohexyl)diisocyanate (H12MDI) units. Prior low molecular weight surfactant studies observed that a CH2 group, introduced as a branch from a linear hydrophobe, contributes approximately half to the surfactant's hydrophobicity that the same CH2 unit would add to the linear chain. Within hydrophobe equivalent comparisons, greater hydrophobic domains are indicated in pyrene's I1/I3 emission ratio for the linear hydrophobe HEURs, denoting a more hydrophilic core in branched HEURs. An increase in the number of -CH2-groups notably influences aqueous solution viscosities, as expected, but among equivalent hydrocarbon comparisons, the moderate-size linear hydrophobe is more viscosifying than the branched hydrophobe at high concentrations. Viscosity increases correlate with the aggregation sizes estimated from DLS studies as aggregate sizes approach 500 nm, covering small to large hydrophobes and different oxyethylene spacer lengths. Conformational differences (Raman spectroscopy) of poly(oxyethylenes) and HEURs under stagnant and flow conditions are also examined. The presence of byproduct impurities can markedly influence these results.

BackgroundThe reconstruction of gene regulatory network (GRN) from gene expression data can discover regulatory relationships among genes and gain deep insights into the complicated regulation mechanism of life. However, it is still a great challenge in systems biology and bioinformatics. During the past years, numerous computational approaches have been developed for this goal, and Bayesian network (BN) methods draw most of attention among these methods because of its inherent probability characteristics. However, Bayesian network methods are time consuming and cannot handle large-scale networks due to their high computational complexity, while the mutual information-based methods are highly effective but directionless and have a high false-positive rate.ResultsTo solve these problems, we propose a Candidate Auto Selection algorithm (CAS) based on mutual information and breakpoint detection to restrict the search space in order to accelerate the learning process of Bayesian network. First, the proposed CAS algorithm automatically selects the neighbor candidates of each node before searching the best structure of GRN. Then based on CAS algorithm, we propose a globally optimal greedy search method (CAS + G), which focuses on finding the highest rated network structure, and a local learning method (CAS + L), which focuses on faster learning the structure with little loss of quality.ConclusionResults show that the proposed CAS algorithm can effectively reduce the search space of Bayesian networks through identifying the neighbor candidates of each node. In our experiments, the CAS + G method outperforms the state-of-the-art method on simulation data for inferring GRNs, and the CAS + L method is significantly faster than the state-of-the-art method with little loss of accuracy. Hence, the CAS based methods effectively decrease the computational complexity of Bayesian network and are more suitable for GRN inference.

A superb supercapacitor with high specific capacitance and high rate capacitance has been developed from taro epidermis biomass-derived carbon materials through a mild carbonizing and activation process. The taro epidermis-derived porous carbon electrodes exhibit a unique cellular frame porous structure with combined micro-and mesopores, and show excellent supercapacitance performance, achieving superior specific capacitance (466 F g −1 at 1 A g −1 ), high energy density (17.59 to 13.97 W h kg −1 ), and excellent rate capacitance (415 F g −1 at 5 A g −1 and 342 F g −1 at 50 A g −1 ) in aqueous 6 M KOH electrolyte. Meanwhile, the taro epidermis derived electrodes demonstrate excellent cycling stability: almost no fading after 40 000 cycles at 5 A g −1 in aqueous 6 M KOH electrolyte and 10 000 cycles at 2.5 A g −1 in organic 1 M TEABF 4 /AN electrolyte. The results demonstrate the effective use of the framework structure of plant cell walls as the highly porous carbon materials with superior supercapacitance performance.

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To gain insight into the epidemiology of childhood drug resistant tuberculosis (DR-TB) in China that has the second largest burden of TB and the largest number of multidrug resistant (MDR) TB cases in the world, we performed the cross-sectional study to investigate drug resistance of four first-line anti-TB drugs (isoniazid, rifampicin, streptomycin and ethambutol) using Mycobacterium tuberculosis isolates from 196 culture-confirmed pediatric TB cases diagnosed in the Children’s Hospital of Chongqing Medical University, China during 2008–2013. Univariate and multivariate logistic regression analyses were performed to assess the associations between patient demographic and clinical characteristics and DR-and MDR-TB, respectively. Twenty-eight percent (56/196) of the study patients exhibited resistance to at least one of the four first-line anti-TB drugs tested. MDR was found in 4.6% (9/196) of the study patients. More than half (5/9, 55.6%) of the MDR cases were from a single county of Chongqing. A significant association was found between being acid-fast bacilli-smear negative and DR-TB (adjusted OR, 2.33; 95% CI, 1.13–4.80) and between having concurrent thoracic-extrathoracic involvement and MDR-TB (adjusted OR, 9.49; 95% CI, 1.05–85.92), respectively. The findings of this study indicate that the rate of DR is high among pediatric TB patients in Chongqing and suggest an urgent need for studies to identify MDR transmission hotspots in Chongqing, thereby contributing to the control DR- and MDR-TB epidemics in China. The study also generates new insight into the pathogenesis of DR and MDR M. tuberculosis strains and highlights the importance of studying childhood TB to the goal of global TB control.