The Bright Side and the Dark Side of Hybrid Organic Inorganic Perovskites

The previously developed bistable amphoteric native defect (BAND) model is used for a comprehensive explanation of the unique photophysical properties and for understanding the remarkable performance of perovskites as photovoltaic materials. It is shown that the amphoteric defects in donor (acceptor) configuration capture a fraction of photoexcited electrons (holes) dividing them into two groups: higher energy bright and lower energy dark electrons (holes). The spatial separation of the dark electrons and the dark holes and the k-space separation of the bright and the dark charge carriers reduce electron hole recombination rates, emulating the properties of an ideal photovoltaic material with a balanced, spatially separated transport of electrons and holes. The BAND model also offers a straightforward explanation for the exceptional insensitivity of the photovoltaic performance of polycrystalline perovskite films to structural and optical inhomogeneities. The blue-shifted radiative recombination of bright electrons and holes results in a large anti-Stokes effect that provides a quantitative explanation for the spectral dependence of the laser cooling effect measured in perovskite platelets

Reliability study of the motor controller of pure electric vans

The market of electric vehicles (EVs) is rapidly growing across the world attributed to their unique feature of zero carbon emission. Take the Chinese market as an example, 984,000 pure electric vehicles were sold in China in 2018, which is an increase of 50.8% over the same period of the previous year. This means there will be more and more electric vehicles will run on the road in the future. However, the reliability of these electric vehicles is still an open issue remaining to resolve today. In particular, the reliability of the motor controller in electric vehicles is receiving more concern than ever before. On the one hand, this is because it is well known that power electronic components in the controller are much less reliable than the mechanical components in other EV subassemblies. One the other hand, it is because the failure of motor controller may lead to dangerous accidents on the road. Previously, much effort has been made to try to predict the reliability of motor controller, however detailed investigation of its reliability issues has never been done before. In view of this, a detailed reliability study of the motor controller in pure electric vans will be conducted in this paper, with the consideration of the fact that more than 90% of sold commercial electric vehicles are pure electric vans. In the research, the detailed root causes of the reliability issues in the motor controller will be investigated first and then based on which the failure rates of individual components (e.g. control module, driver module, communication module, and discharging module) in the controller will be estimated with the aid of fault tree analysis and the international standards IEC TR62308-2004, MIL-HDBH-217E and the technical standards for the Chinese electric vehicle industry. Finally, the tendency of the unreliability index of the entire motor controller against the service life of the electric vehicle is estimated based on the fault tree analysis results in order to obtain a more reliable understanding of the reliability performance of the motor controller over time. From such detailed reliability research, it has been found that the reliability performance of the motor controller will degrade gradually over time; and among the four functional modules of the controller the control module is most vulnerable, followed by driver module. This could be due to the application of more electronic components and thinner printed lines on the module

Isolation and characterization of a bacterium able to degrade high concentration of iprodione

A bacterial strain CQH-1 capable of mineralizing iprodione was isolated and characterized. In combination with morphological, physiological biochemical characters, and the phylogenetic analysis of 16S rRNA gene sequence, strain CQH-1 was identified as Microbacterium sp.. It could use iprodione and 3,5-dichloroaniline as the sole carbon source and energy source for growth. It completely degraded 100 mg L-1 of iprodione within 96 h at 30 째C. During the degradation of iprodione by strain CQH-1, two compounds were detected in GC-MS analysis and recognized as N-(3,5-dichlorophenyl)-2,4-dioxoimidazolidine and 3,5-dichloroaniline, respectively. So, the biodegradation pathway of iprodione by strain CQH-1 was proposed. This is the first report of iprodione-mineralizing strain from the genus of Microbacterium, and strain CQH-1 might be a promising candidate for its application in the bioremediation of iprodione-contaminated environments.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author

PAS Domain-Containing Chemoreceptors Influence the Signal Sensing and Intestinal Colonization of Vibrio cholerae

Bacterial chemotaxis is the phenomenon in which bacteria migrate toward a more favorable niche in response to chemical cues in the environment. The methyl-accepting chemotaxis proteins (MCPs) are the principal sensory receptors of the bacterial chemotaxis system. Aerotaxis is a special form of chemotaxis in which oxygen serves as the signaling molecule; the process is dependent on the aerotaxis receptors (Aer) containing the Per-Arnt-Sim (PAS) domain. Over 40 MCPs are annotated on the genome of Vibrio cholerae; however, little is known about their functions. We investigated six MCPs containing the PAS domain in V. cholerae El Tor C6706, namely aer2, aer3, aer4, aer5, aer6, and aer7. Deletion analyses of each aer homolog gene indicated that these Aer receptors are involved in aerotaxis, chemotaxis, biofilm formation, and intestinal colonization. Swarming motility assay indicated that the aer2 gene was responsible for sensing the oxygen gradient independent of the other five homologs. When bile salts and mucin were used as chemoattractants, each Aer receptor influenced the chemotaxis differently. Biofilm formation was enhanced by overexpression of the aer6 and aer7 genes. Moreover, deletion of the aer2 gene resulted in better bacterial colonization of the mutant in adult mice; however, virulence gene expression was unaffected. These data suggest distinct roles for different Aer homologs in V. cholerae physiology

Bacteriophage SRD2021 Recognizing Capsular Polysaccharide Shows Therapeutic Potential in Serotype K47 Klebsiella pneumoniae Infections

Klebsiella pneumoniae is an opportunistic pathogen posing an urgent threat to global public health, and the capsule is necessary for K. pneumoniae infection and virulence. Phage-derived capsule depolymerases have shown great potential as antivirulence agents in treating carbapenem-resistant K. pneumoniae (CRKP) infections. However, the therapeutic potential of phages encoding depolymerases against CRKP remains poorly understood. In this study, we identified a long-tailed phage SRD2021 specific for mucoid CRKP with capsular K47 serotype, which is the predominant infectious K-type in Asia. Genome sequencing revealed that ΦSRD2021 belonged to the Drulisvirus genus and exhibited a capsular depolymerase domain in its tail fiber protein. A transposon-insertion library of host bacteria was constructed to identify the receptor for ΦSRD2021. We found that most phage-resistant mutants converted to a nonmucoid phenotype, including the mutant in wza gene essential for capsular polysaccharides export. Further knockout and complementation experiments confirmed that the Δwza mutant avoided adsorption by ΦSRD2021, indicating that the K47 capsular polysaccharide is the necessary receptor for phage infection. ΦSRD2021 lysed the bacteria mature biofilms and showed a therapeutic effect on the prevention and treatment of CRKP infection in the Galleria mellonella model. Furthermore, ΦSRD2021 also reduced the colonized CRKP in mouse intestines significantly. By recognizing the host capsule as a receptor, our results showed that ΦSRD2021 may be used as a potential antibacterial agent for K47 serotype K. pneumoniae infections

Nontargeted Metabolomics Revealed Novel Association Between Serum Metabolites and Incident Acute Coronary Syndrome: A Mendelian Randomization Study

Background This study was performed to identify metabolites associated with incident acute coronary syndrome (ACS) and explore causality of the associations. Methods and Results We performed nontargeted metabolomics in a nested case‐control study in the Dongfeng‐Tongji cohort, including 500 incident ACS cases and 500 age‐ and sex‐matched controls. Three metabolites, including a novel one (aspartylphenylalanine), and 1,5‐anhydro‐d‐glucitol (1,5‐AG) and tetracosanoic acid, were identified as associated with ACS risk, among which aspartylphenylalanine is a degradation product of the gut‐brain peptide cholecystokinin‐8 rather than angiotensin by the angiotensin‐converting enzyme (odds ratio [OR] per SD increase [95% CI], 1.29 [1.13–1.48]; false discovery rate–adjusted P=0.025), 1,5‐AG is a marker of short‐term glycemic excursions (OR per SD increase [95% CI], 0.75 [0.64–to 0.87]; false discovery rate–adjusted P=0.025), and tetracosanoic acid is a very‐long‐chain saturated fatty acid (OR per SD increase [95% CI], 1.26 [1.10–1.45]; false discovery rate–adjusted P=0.091). Similar associations of 1,5‐AG (OR per SD increase [95% CI], 0.77 [0.61–0.97]) and tetracosanoic acid (OR per SD increase [95% CI], 1.32 [1.06–1.67]) with coronary artery disease risk were observed in a subsample from an independent cohort (152 and 96 incident cases, respectively). Associations of aspartylphenylalanine and tetracosanoic acid were independent of traditional cardiovascular risk factors (P‐trend=0.015 and 0.034, respectively). Furthermore, the association of aspartylphenylalanine was mediated by 13.92% from hypertension and 27.39% from dyslipidemia (P<0.05), supported by its causal links with hypertension (P<0.05) and hypertriglyceridemia (P=0.077) in Mendelian randomization analysis. The association of 1,5‐AG with ACS risk was 37.99% mediated from fasting glucose, and genetically predicted 1,5‐AG level was negatively associated with ACS risk (OR per SD increase [95% CI], 0.57 [0.33–0.96], P=0.036), yet the association was nonsignificant when further adjusting for fasting glucose. Conclusions These findings highlighted novel angiotensin‐independent involvement of the angiotensin‐converting enzyme in ACS cause, and the importance of glycemic excursions and very‐long‐chain saturated fatty acid metabolism