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In this work, a metal/Ga2O3/AlGaN/GaN hybrid-structured metal–semiconductor–metal ultraviolet photodetector (MSM UV PD) with low dark current has been proposed and fabricated. In the dark condition, the depletion region formed by the metal gate and the AlGaN layer pinches off the two-dimensional electron gas (2DEG) channel, and we can obtain a dark current even lower than 10−10 A/cm2. In the illumination condition, due to the electric field formed by the metal and the Ga2O3 layer, the photogenerated electrons will move to the AlGaN/GaN channel to form the 2DEG. We then get a photo-to-dark current ratio of $8.77\times10$ 8. Furthermore, the detectivity of the device is higher than $3.30\times10$ 12 Jones when a 254-nm UV illumination signal is applied.

In the present work, 15 400 yr old geochemical records of a core from the subalpine Daping swamp are presented with the aim to examine the relationship between the chemical weathering and the climatic changes in the region of the western Nanling Mountains, China. The climate of the study region was deeply controlled by the East Asian summer monsoon. The results indicate that, in the past 15 400 yrs, the values of chemical index of alteration (CIA) ranged from 73.9% to 88.2% (mean: 85.3%), suggested a medium and high intensity of chemical weathering. The local exogenous clastic materials, which were derived from the weathered residues, played a key role in contributing towards the sediments. Since the climate-induced chemical weathering exerted strong influences on the geochemical features of weathered residues, the geochemical characteristics of the sediments were deeply impacted by climatic conditions. Wetter and warmer conditions would favor increased chemical weathering, resulting in more leaching of soluble and mobile elements (e.g., Ba and Sr) and leaving the resistant and immobile elements (e.g., Al and Ti) enriched in the weathered residues. These materials were then eroded and transported into the lake, and led to the sediments characterized by the characteristic of having depleted soluble elements. In contrast, dry and cold conditions would result in an opposite trend. In this sense, the geochemical records can serve as proxies to indicate changes of chemical weathering intensity, which were closely related to the evolution of summer monsoon.

Water pollution caused by Hg(II) and Ag(I) poses deleterious effects to environmental safety. Adsorption is one of the promising methods to decontaminate aqueous metal ions. Herein, polyhydroxyl-capped poly(amidoamine) (PAMAM) dendrimer/silica composites (G1-OH and G2-OH) were prepared for decontaminating aqueous Hg(II) and Ag(I). The maximum adsorption capacity of G1-OH and G2-OH for Hg(II) are 0.45 and 0.76 mmol/g, while that for Ag(I) are 0.66 and 0.81 mmol/g. The optimum solution pH for the adsorption of Hg(II) and Ag(I) are both 6. The adsorption for Hg(II) and Ag(I) can reach equilibrium at 150 and 120 min, respectively. Pseudo-second-order model can be used to describe the adsorption kinetic process and the rate-controlling step is film diffusion process. Adsorption isotherm indicates the adsorption can be promoted by increasing concentration and temperature, and the adsorption process could be described by Langmuir model with chemical mechanism. G1-OH and G2-OH exhibit excellent adsorption selectivity and they can 100% adsorb Hg(II) or Ag(I) with the coexisting of Fe(III), Co(II), Cu(II) or Ni(II). Adsorption mechanism confirms C-N, OH and CONH groups play critical role for the adsorption of the two ions. The work may provide efficient adsorbents for the decontamination of aqueous Hg(II) and Ag(I) with practical value.

The correlation between contact fatigue failure and wear failure of rolling bearing is analyzed, and the reliability model of rolling bearing based on multi-correlation failure mode is established. Based on the improved linear fatigue cumulative damage theory and wear theory, the limit state equations of two failure modes are established, and the correlation of state functions of contact fatigue and wear failure modes is described by the mixed Copula function. The random sample data are generated by Monte Carlo method, and the unknown parameters are estimated by genetic algorithm based on the minimum deviation square criterion, then the dynamic reliability model of rolling bearing is established. The quadratic polynomial without cross-term is used as the implicit functional proxy model, then the Latin hypercube sampling method and least squares theory are employed to estimate parameters of mixed Copula function and finally, the reliability sensitivity analysis of multi-failure modes of bearing is presented by fourth-order moment estimation method. Taking a certain type of spherical roller bearing as an example, the bearing reliability analysis considering the correlation of failure modes is carried out. The results show that compared with the bearing reliability model based on the assumption of independent failure modes and the weakest link theory, the bearing reliability model based on multi-correlation failure is more consistent with the practical application.

Using the three-phase cooperation model and analysing projects based on their cooperation demands in the planning, implementation and operation phases, this article answers three main questions for each of the abovementioned phases: (i) How and between which systems do cross-connections occur? (ii) Which actors are involved in those phases? (iii) Who needs to participate in which type of governance to achieve a better, more structured process of cross-connection control? The article refers to the world's largest novel water system in the Chinese city of Qingdao where a Resource Recovery Centre (RRC) providing the treatment of greywater for domestic and landscape reuse for 12,000 inhabitants has been implemented. A systematic interdisciplinary analysis of crossconnections leads to the conclusion that the approach to source separation needs to be complemented by governance instruments. These governance instruments derived from the actors identified by the cooperation management approach comprise processes of deliberation and communication, qualification and certification, final approval and inspection, as well as learning and evaluation. [ABSTRACT FROM AUTHOR]

ABSTRACTBackground:To evaluate the one-year immunogenicity and safety of a subunit plague vaccine. Methods:In the initial study, 240 healthy adults aged 18–55 years were administrated with 2 doses of 15 or 30 µg plague vaccines at day 0 and 28, respectively. In this extended follow-up study, we evaluated the immunogenicity and safety of the plague vaccine up to one year. Results:For antibody to envelope antigen faction 1 (F1) antigen, titers were up to new peaks at month 6, then declined slowly to month 12, but remained at higher levels than those at day 56. Geometric mean titers (GMTs) of F1 were significantly higher in 30 µg group than those in 15 µg group at month 6 and 12 (P< 0.0001 and P< 0.001). However, approximate 100% seroconversion rates of F1 antibodies were found in both 15 and 30 µg groups at the both time points. For antibody to recombinant virulence (rV) antigen, titers and seroconversion rates were decreased sharply at month 6 and continue to decrease at month 12. GMTs and seroconversion rates were not significantly different between the 15 and 30 µg groups, respectively. No serious adverse events (SAEs) related to vaccine occurred. Conclusion:The new plague vaccine (F1+rV) induced a robust immune response up to 12 months and showed a good safety profile in adults aged 18–55 years.

A novel turn-on fluorescent probe (DDND) for highly selective detection of biothiols over other amino acids was synthesized and investigated in this work, which used the 2,4-dinitrobenzenesulfonyl (DNBS) group as a fluorescent quencher. The novel fluorophore (HDM) features a large π-conjugation system and a typical intramolecular charge transfer (ICT) process and has a long emission wavelength at 623 nm as well as a large Stokes shift (λem− λex= 131 nm). Besides that, this red-emitting probe exhibited good linearity ranges with a low detection limit of 0.23 μM for Cys, 0.34 μM for Hcy and 0.41 μM for GSH respectively. Upon titration of thiols, the color of the solution changed from yellow to dark red, which means it can be detected by naked eyes. Finally, probe DDNDwas successfully applied to bioimage intracellular Cys in HeLa cells with low cytotoxicity.

ABSTRACTBackground:Although the killed whole-cell and live attenuated plague vaccine have been licensed, they are rarely used today because of toxicities, limited evidence of efficacy against plague, poor immune persistence required booster immunization every year, and limited commercial availability. This study was a randomized phase 2a clinical trial aimed to evaluating the immunogenicity and safety of a novel subunit plague vaccine. Methods:240 healthy adults aged 18–55 y were enrolled and randomly assigned at a ratio of 1:1 to receive 2 doses of 15 or 30 mcg vaccine at a 28-day interval between doses. Blood samples were collected at day 0, 28 and 56. Adverse events were collected during the first 28 d after each vaccination. Serious Adverse Event was observed throughout the study period. Results:239 participants received the first dose at day 0 and 238 received the second dose at day 28. Antibodies to envelope antigen faction 1 (F1) and recombinant virulence antigen (rV) were increased at day 28, and boosted significantly at day 56. For anti-F1 antibodies, geometric mean titer (GMT) and geometric mean fold increase (GMFI) were significantly higher in 30 mcg group than in the 15 mcg group(each P1< 0.05 at day 28 and each P1< 0.001 at day 56), with similar seroconversion rate of antibodies between 15 and 30 mcg group at both of the 2 time points. For anti-rV antibodies, seroconversion rate at day 28 in 30 mcg group was higher than that in 15 mcg group. However, GMT and GMFI of anti-rV antibodies were increased to approximately the same levels in the 2 groups. Similar booster immune response was also noticed in both groups at day 56. The injections were well tolerated, with mainly mild or moderate local and systemic adverse reactions (lower than grad 3). The proportion of pain at injection site was higher in 30 mcg group. None of SAEs were reported during 56 d. Conclusion:The plague vaccine comprised of F1 and rV antigens showed good safety and immunogenicity in adults aged 18–55 y old. The data show that the 30 mcg formulation is generally more immunogenic than the 15 mcg formulation, and represents the preferred formulation for further clinical development. It will be important to evaluate the long-term efficacy for appropriate formulations of the plague subunit vaccine.

ABSTRACTAnthrax toxins and capsule are the major virulence factors of Bacillus anthracis. They are encoded by genes located on the plasmids pXO1 and pXO2, respectively. The vaccine strain Pasteur II was produced from high temperature subcultures of B. anthracis, which resulted in virulence attenuation through the loss of the plasmid pXO1. However, it is unclear whether the high temperature culture completely abolishes the plasmid DNA or affects the replication of the plasmid pXO1. In this study, we tested 3 B. anthracisvaccine strains, including Pasteur II from France, Qiankefusiji II from Russia, and Rentian II from Japan, which were all generated from subcultures at high temperatures. Surprisingly, we detected the presence of pXO1 plasmid DNA using overlap PCR in all these vaccine strains. DNA sequencing analysis of overlap PCR products further confirmed the presence of pXO1. Moreover, the expression of the protective antigen (PA) encoded on pXO1 was determined by using SDS-PAGE and western blotting. In addition, we mimicked Pasteur's method and exposed the A16R vaccine strain, which lacks the pXO2 plasmid, to high temperature, and identified the pXO1 plasmid in the subcultures at high temperatures. This indicated that the high temperature treatment at 42.5°C was unable to eliminate pXO1 plasmid DNA from B. anthracis. Our results suggest that the attenuation of the Pasteur II vaccine strain is likely due to the impact of high temperature stress on plasmid replication, which in turn limits the copy number of pXO1. Our data provide new insights into the mechanisms of the remaining immunogenicity and toxicity of the vaccine strains.

ABSTRACTTo develop an effective subunit vaccine which could target tubercle bacilli with different metabolic states and provide effective protective immunity, we fused antigens ESAT6, Ag85B, peptide 190–198 of MPT64, and Mtb8.4 mainly expressed by proliferating bacteria and latency-associated antigen Rv2626c together to construct a multistage protein ESAT6-Ag85B-MPT64(190–198)-Mtb8.4-Rv2626c (LT70 for short) with the molecular weight of 70 kDa. The human T-cell responses to LT70 and other antigens were analyzed. The immune responses of LT70 in the adjuvant of DDA and Poly I:C and its protective efficacy against Mycobacterium tuberculosis(M. tuberculosis) infection in C57BL/6 mice were evaluated. The results showed that LT70 was stably produced in Escherichia coliand could be purified by successive salting-out and chromatography. LT70 could be strongly recognized by human T cells from TB patients and persons who are supposed latently infected with M. tuberculosis. The subunit vaccine LT70 generated strong antigen-specific humoral and cell-mediated immunity, and induced higher protective efficacy (5.41±0.37 Log10CFU in lung) than traditional vaccine Bacillus Calmette-Guerin (6.01±0.33 Log10CFU) and PBS control (6.53±0.26 Log10CFU) at 30 weeks post vaccination (10 weeks post-challenge) against M. tuberculosisinfection (p< 0.05). These findings suggested that LT70 would be a promising subunit vaccine candidate against M. tuberculosisinfection.

The Brucella abortusstrain 104M, a spontaneously attenuated strain, has been used as a vaccine strain in humans against brucellosis for 6 decades in China. Despite many studies, the molecular mechanisms that cause the attenuation are still unclear. Here, we determined the whole-genome sequence of 104M and conducted a comprehensive comparative analysis against the whole genome sequences of the virulent strain, A13334, and other reference strains. This analysis revealed a highly similar genome structure between 104M and A13334. The further comparative genomic analysis between 104M and A13334 revealed a set of genes missing in 104M. Some of these genes were identified to be directly or indirectly associated with virulence. Similarly, a set of mutations in the virulence-related genes was also identified, which may be related to virulence alteration. This study provides a set of candidate genes associated with virulence attenuation in B.abortus vaccine strain 104M.

An oxidant promoted 1,3dipolar cycloaddition of benzimidazolium ylides to alkenes was developed for the preparation of 4Hpyrrolo1,2abenzimidazole derivatives in moderate yields under mild conditions. In the presence of a suitable oxidant, the most commercially available “normal” alkenes, instead of alkynes or “abnormal” alkenes, could be used as dipolarophiles successfully. Moreover, CrO3Et3N has been proved to be a more effective dehydrogenating reagent than MnO2or tetrakispyridine cobalt II dichromate TPCD in this procedure.

The purpose of this paper is to present a new method to redesign dimensional and geometric tolerances of mechanical assemblies at a lower cost and with higher reliability. A parametric Jacobian-Torsor model is proposed to conduct tolerance analysis of mechanical assembly. A reliability-based tolerance optimization model is established. Differing from previous studies of fixed process parameters, this research determines the optimal process variances of tolerances, which provide basis for the subsequent assembly tolerance redesign. By using the Lambert W function and the Lagrange multiplier method, the analytical solution of the parametric tolerance optimization model is obtained. A numerical example is presented to demonstrate the effectiveness of the model, while the results indicate that the total cost is reduced by 10.93% and assembly reliability improves by 2.12%. This study presents an efficient reliability-based tolerance optimization model. The proposed model of tolerance redesign can be used for mechanical assembly with a better economic effect and higher reliability.

AbstractAromatization of Hantzsch 1,4-dihydropyridines (la-n) were promoted by tetrakis-pyridine cobalt (11) dichromate to yield corresponding pyridine derivatives (2a-n) in moderate to high yields (70-87%). The reaction was carried out under mild and convenient conditions.

Structural optimization based on natural products is an important and effective way to discover new green pesticides. Here, two series of amide derivatives based on sinapic acid and mycophenolic acid were designed in combination with the fungicidal natural product piperlongumine and synthesized by preparing the carboxylic acid into acyl chloride and then reacting with the corresponding aromatic amines, respectively. The resulting structures were successively characterized by 1H NMR, 13 C NMR, and HRMS. The crystal structures of molecules I-4 and II-5 were analyzed for structure validation. The in vitro inhibitory activity indicated that most of the target products exhibited fungicidal activity equivalent to or even better than fluopyram against Physalospora piricola. The in vivo fungicidal activity demonstrated that the compounds I-5 and II-4 displayed almost the same preventative activity as carbendazim and fluopyram at 200 μg mL−1. The TEM observation revealed that the fungicidal activity of the target molecules against Physalospora piricola may be due to the influence on the mitochondria in the cell structure. These results will provide valuable theoretical guidance for developing the new green fungicides.

A class of silica anchored Schiff base decorated polyamidoamine (PAMAM) dendrimers were synthesized for removing aqueous Cu(II) and Ag(I). The adsorption performance was investigated synthetically and the adsorption mechanism was revealed. Results indicate the adsorption capacity depends on dendrimer generation, solution pH, contact time, temperature and initial metal ion concentration. The optimum adsorption pH is 6 for both metal ion. Adsorption kinetic suggests the adsorption can achieve equilibrium at 180 and 150 min for Cu(II) and Ag(I). The kinetic process is found to be in good agreement with pseudo-second-order model and film diffusion is the rate-controlling step. The adsorption isotherm indicates the adsorption is proceeded by monolayer behavior with chemical mechanism. These adsorbents exhibit competitive adsorption capacity as compared with other reported adsorbents. Theoretical calculation demonstrates the participation of hydroxyl, carbonyl, and amide groups during the adsorption of Cu(II), while hydroxyl and amide groups are mainly responsible for capturing Ag(I).

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.