Momentum matching and band-alignment type in van der Waals heterostructures: Interfacial effects and materials screening

Momentum-matched type II van der Waals heterostructures (vdWHs) have been designed by assembling layered two-dimensional semiconductors (2DSs) with special band-structure combinations - that is, the valence band edge at the Gamma point (the Brillouin-zone center) for one 2DS and the conduction band edge at the Gamma point for the other [Ubrig et al., Nat. Mater. 19, 299 (2020)]. However, the band offset sizes, band-alignment types, and whether momentum matched or not, all are affected by the interfacial effects between the component 2DSs, such as the quasichemical-bonding (QB) interaction between layers and the electrical dipole moment formed around the vdW interface. Here, based on density-functional theory calculations, first we probe the interfacial effects (including different QBs for valence and conduction bands, interface dipole, and, the synergistic effects of these two aspects) on band-edge evolution in energy and valley (location in the Brillouin zone) and the resulting changes in band alignment and momentum matching for a typical vdWH of monolayer InSe and bilayer WS2, in which the band edges of subsystems satisfy the special band-structure combination for a momentum-matched type II vdWH. Then, based on the conclusions of the studied interfacial effects, we propose a practical screening method for robust momentum-matched type II vdWHs. This practical screening method can also be applied to other band alignment types. Our current study opens a way for practical screening and designing of vdWHs with robust momentum-matching and band alignment type

Yersinia pseudotuberculosis Exploits CD209 Receptors for Promoting Host Dissemination and Infection

Yersinia pseudotuberculosis is a Gram-negative enteropathogen and causes gastrointestinal infections. It disseminates from gut to mesenteric lymph nodes (MLNs), spleen, and liver of infected humans and animals. Although the molecular mechanisms for dissemination and infection are unclear, many Gram-negative enteropathogens presumably invade the small intestine via Peyer's patches to initiate dissemination. In this study, we demonstrate that Y. pseudotuberculosis utilizes its lipopolysaccharide (LPS) core to interact with CD209 receptors, leading to invasion of human dendritic cells (DCs) and murine macrophages. These Y. pseudotuberculosis CD209 interactions result in bacterial dissemination to MLNs, spleens, and livers of both wild-type and Peyer's patch-deficient mice. The blocking of the Y. pseudotuberculosis CD209 interactions by expression of 0-antigen and with oligosaccharides reduces infectivity. Based on the well-documented studies in which HIV-CD209 interaction leads to viral dissemination, we therefore propose an infection route for Y. pseudotuberculosis where this pathogen, after penetrating the intestinal mucosal membrane, hijacks the Y. pseudotuberculosis CD209 interaction antigen-presenting cells to reach their target destinations, MLNs, spleens, and livers.Peer reviewe

Infection control and the burden of tuberculosis infection and disease in health care workers in china: a cross-sectional study

<p>Abstract</p> <p>Background</p> <p>Hospitals with inadequate infection control are risky environments for the emergence and transmission of tuberculosis (TB). We evaluated TB infection control practices, and the prevalence of latent TB infection (LTBI) and TB disease and risk factors in health care workers (HCW) in TB centers in Henan province in China.</p> <p>Methods</p> <p>A cross-sectional survey was conducted in 2005. To assess TB infection control practices in TB centers, checklists were used. HCW were tuberculin skin tested (TST) to measure LTBI prevalence, and were asked for sputum smears and chest X-rays to detect TB disease, and questionnaires to assess risk factors. Differences between groups for categorical variables were analyzed by binary logistic regression. The clustered design of the study was taken into account by using a multilevel logistic model.</p> <p>Results</p> <p>The assessment of infection control practices showed that only in a minority of the centers the patient consultation areas and X-ray areas were separated from the waiting areas and administrative areas. Mechanical ventilation was not available in any of the TB centers. N95 respirators were not available for HCW and surgical masks were not available for TB patients and suspects. The LTBI prevalence of HCW with and without BCG scar was 55.6% (432/777) and 49.0% (674/1376), respectively (P = 0.003). Older HCW, HCW with longer duration of employment, and HCW who worked in departments with increased contact with TB patients had a higher prevalence of LTBI. HCW who work in TB centers at the prefecture level, or with an inpatient ward also had a higher prevalence of LTBI. Twenty cases of pulmonary TB were detected among 3746 HCW. The TB prevalence was 6.7/1000 among medical staff and 2.5/1000 among administrative/logistic staff.</p> <p>Conclusion</p> <p>TB infection control in TB centers in Henan, China, appears to be inadequate and the prevalence of LTBI and TB disease among HCW was high. TB infection control practices in TB centers should be strengthened in China, including administrative measures, renovation of buildings, and use of respirators and masks. Regular screening of HCW for TB disease and LTBI needs to be considered, offering preventive therapy to those with TST conversions.</p

Sox2 Is Essential for Formation of Trophectoderm in the Preimplantation Embryo

In preimplantation mammalian development the transcription factor Sox2 (SRY-related HMG-box gene 2) forms a complex with Oct4 and functions in maintenance of self-renewal of the pluripotent inner cell mass (ICM). Previously it was shown that Sox2-/- embryos die soon after implantation. However, maternal Sox2 transcripts may mask an earlier phenotype. We investigated whether Sox2 is involved in controlling cell fate decisions at an earlier stage.We addressed the question of an earlier role for Sox2 using RNAi, which removes both maternal and embryonic Sox2 mRNA present during the preimplantation period. By depleting both maternal and embryonic Sox2 mRNA at the 2-cell stage and monitoring embryo development in vitro we show that, in the absence of Sox2, embryos arrest at the morula stage and fail to form trophectoderm (TE) or cavitate. Following knock-down of Sox2 via three different short interfering RNA (siRNA) constructs in 2-cell stage mouse embryos, we have shown that the majority of embryos (76%) arrest at the morula stage or slightly earlier and only 18.7-21% form blastocysts compared to 76.2-83% in control groups. In Sox2 siRNA-treated embryos expression of pluripotency associated markers Oct4 and Nanog remained unaffected, whereas TE associated markers Tead4, Yap, Cdx2, Eomes, Fgfr2, as well as Fgf4, were downregulated in the absence of Sox2. Apoptosis was also increased in Sox2 knock-down embryos. Rescue experiments using cell-permeant Sox2 protein resulted in increased blastocyst formation from 18.7% to 62.6% and restoration of Sox2, Oct4, Cdx2 and Yap protein levels in the rescued Sox2-siRNA blastocysts.We conclude that the first essential function of Sox2 in the preimplantation mouse embryo is to facilitate establishment of the trophectoderm lineage. Our findings provide a novel insight into the first differentiation event within the preimplantation embryo, namely the segregation of the ICM and TE lineages

Six-membered ring systems: with O and/or S atoms

A large variety of publications have emerged in 2012 involving O- and S-6- membered ring systems. The increasing number of reviews and other communica- tions dedicated to natural and synthetic derivatives and their biological significance highlights the importance of these heterocycles. Reviews on natural products involve biosynthesis and isolation of enantiomeric derivatives h12AGE4802i, biosynthesis, isolation, synthesis, and biological studies on the pederin family h12NPR980i and xanthones obtained from fungi, lichens, and bacteria h12CR3717i and on the potential chemotherapeutic value of phyto- chemical products and plant extracts as antidiabetic h12NPR580i, antimicrobial, and resistance-modifying agents h12NPR1007i. A more specific review covers a structure–activity relationship of endoperoxides from marine origin and their antitry- panosomal activity h12OBC7197i. New synthetic routes to naturally occurring, biologically active pyran derivatives have been the object of several papers. Different approaches have been discussed for the total synthesis of tetrahydropyran-containing natural products (")-zampanolide h12CEJ16868, 12EJO4130, 12OL3408i, (")-aspergillides A and B h12H(85)587, 12H(85)1255, 12TA252i, (þ)-neopeltolide h12JOC2225, 12JOC9840, 12H(85) 1255i, or their macrolactone core h12OBC3689, 12OL2346i. The total synthesis of bistramide A h12CEJ7452i and (þ)-kalihinol A h12CC901i and the stereoselec- tive synthesis of a fragment of bryostatin h12S3077, 12TL6163i have also been sur- veyed. Other papers relate the total synthesis of naturally occurring carbocyclic and heterocyclic-fused pyran compounds, such as (")-dysiherbaine h12CC6295i, penos- tatin B h12OL244i, Greek tobacco lactonic products, and analogues h12TL4293i and on the structurally intriguing limonoids andhraxylocarpins A–E h12CEJ14342i. The stereocontrolled synthesis of fused tetrahydropyrans was used in the preparation of blepharocalyxin D h12AGE3901i. Polyphenolic heterocyclic compounds have also received great attention in 2012. The biological activities and the chemistry of prenylated caged xanthones h12PCB78i, the occurrence of sesquiterpene coumarins h12PR77i, and the medicinal properties of the xanthone mangiferin h12MRME412i have been reviewed. An overview on the asymmetric syntheses of flavanones and chromanones h12EJO449i, on the synthesis and reactivity of flavones h12T8523i and xanthones h12COC2818i, on the synthesis and biosynthesis of biocoumarins h12T2553i, and on the synthesis and applications of flavylium compounds h12CSR869i has been discussed. The most recent developments in the synthesis and applications of sultones, a very important class of sulfur compounds, were reported h12CR5339i. A review on xanthene-based fluorescent probes for sensing cations, anions, bio- logical species, and enzyme activity has described the spiro-ring-opening approach with a focus on the major mechanisms controlling their luminescence behavior h12CR1910i. The design and synthesis of other derivatives to be used as sensors of gold species h12CC11229i and other specific metal cations h12PC823i have also been described. Recent advances related to coumarin-derived fluorescent chemosen- sors for metal ions h12COC2690i and to monitoring in vitro analysis and cellular imaging of monoamine oxidase activity h12CC6833i have been discussed. The study of various organic chromophores allowed the synthesis of novel dica- tionic phloroglucinol-type bisflavylium pigments h12SL2053i, and the optical and spectroscopic properties of several synthetic 6-aryldibenzo[b,d]pyrylium salts were explored h12TL6433i. Discussion of specific reactions leading to O- and S-membered heterocyclic compounds covers intramolecular radical cyclization h12S2475i and asymmetric enamine and dienamine catalysis h12EJO865i, oxa-Michael h12CSR988i and dom- ino Knoevenagel–hetero-Diels–Alder (hDA) reactions h12T5693i, and the versatility in cycloadditions as well as nucleophilic reactions using o-quinones h12CSR1050i. The use of specific reagents relevant to this chapter includes molecular iodine h12CEJ5460, 12COS561i, samarium diiodide–water for selective reductive transfor- mations h12CC330i, o-quinone methides as versatile intermediates h12CEJ9160i, InCl3 as catalyst h12T8683i, and gold and platinum p-acid mediated insertion of alkynes into carbon–heteroatom s-bonds h12S3401i. The remainder of this chapter discusses the most studied transformations on O- and S-6-membered heterocycles

Global patient outcomes after elective surgery: prospective cohort study in 27 low-, middle- and high-income countries.

BACKGROUND: As global initiatives increase patient access to surgical treatments, there remains a need to understand the adverse effects of surgery and define appropriate levels of perioperative care. METHODS: We designed a prospective international 7-day cohort study of outcomes following elective adult inpatient surgery in 27 countries. The primary outcome was in-hospital complications. Secondary outcomes were death following a complication (failure to rescue) and death in hospital. Process measures were admission to critical care immediately after surgery or to treat a complication and duration of hospital stay. A single definition of critical care was used for all countries. RESULTS: A total of 474 hospitals in 19 high-, 7 middle- and 1 low-income country were included in the primary analysis. Data included 44 814 patients with a median hospital stay of 4 (range 2-7) days. A total of 7508 patients (16.8%) developed one or more postoperative complication and 207 died (0.5%). The overall mortality among patients who developed complications was 2.8%. Mortality following complications ranged from 2.4% for pulmonary embolism to 43.9% for cardiac arrest. A total of 4360 (9.7%) patients were admitted to a critical care unit as routine immediately after surgery, of whom 2198 (50.4%) developed a complication, with 105 (2.4%) deaths. A total of 1233 patients (16.4%) were admitted to a critical care unit to treat complications, with 119 (9.7%) deaths. Despite lower baseline risk, outcomes were similar in low- and middle-income compared with high-income countries. CONCLUSIONS: Poor patient outcomes are common after inpatient surgery. Global initiatives to increase access to surgical treatments should also address the need for safe perioperative care. STUDY REGISTRATION: ISRCTN5181700

Guidelines for the use and interpretation of assays for monitoring autophagy (4th edition)1.

In 2008, we published the first set of guidelines for standardizing research in autophagy. Since then, this topic has received increasing attention, and many scientists have entered the field. Our knowledge base and relevant new technologies have also been expanding. Thus, it is important to formulate on a regular basis updated guidelines for monitoring autophagy in different organisms. Despite numerous reviews, there continues to be confusion regarding acceptable methods to evaluate autophagy, especially in multicellular eukaryotes. Here, we present a set of guidelines for investigators to select and interpret methods to examine autophagy and related processes, and for reviewers to provide realistic and reasonable critiques of reports that are focused on these processes. These guidelines are not meant to be a dogmatic set of rules, because the appropriateness of any assay largely depends on the question being asked and the system being used. Moreover, no individual assay is perfect for every situation, calling for the use of multiple techniques to properly monitor autophagy in each experimental setting. Finally, several core components of the autophagy machinery have been implicated in distinct autophagic processes (canonical and noncanonical autophagy), implying that genetic approaches to block autophagy should rely on targeting two or more autophagy-related genes that ideally participate in distinct steps of the pathway. Along similar lines, because multiple proteins involved in autophagy also regulate other cellular pathways including apoptosis, not all of them can be used as a specific marker for bona fide autophagic responses. Here, we critically discuss current methods of assessing autophagy and the information they can, or cannot, provide. Our ultimate goal is to encourage intellectual and technical innovation in the field

MicroRNA-144 silencing attenuates intimal hyperplasia by directly targeting PTEN

Background Intimal hyperplasia contributed by phenotypic switching of vascular smooth muscle cell (VSMC) plays an important role in the pathogenesis of various cardiovascular diseases. MicroRNA-144 (miR-144) is recently reported to be implicated in the development of atherosclerosis. However, the individual role of miR-144 in VSMCs phenotypic modulation and intimal hyperplasia currently still remains unknown. Methods and Results Here we found that miR-144 expression was upregulated in carotid arteries with intimal hyperplasia that subjected to wire injury and the consistent results were obtained with dedifferentiated VSMCs upon platelet-derived growth factor-BB (PDGF-BB) stimulation. Loss-of-function study showed that miR-144 knockdown decreased the ability of VSMC proliferation tested by Brdu and CCK8, and reduced the migrate capability analyzed by Transwell, whereas increased the differentiated SMC marker gene expression examined by RT-PCR. The above results were reversed by miR-144 overexpression. Mechanistically, we have demonstrated that PTEN was the direct target of miR-144 that was responsible for the alleviated effect of miR-144 inhibition on phenotypic switching of VSMCs. Notably, mice injected with miR-144 inhibitor attenuated the formation of neointimal lesions in response to wire injury and maintained the mature SMC marker expression inhibited the proliferation and migration of VSMCs. Conclusion Our research exhibited that miR-144 knockdown attenuated intimal hyperplasia through inhibiting the VSMC phenotypic switching, which was partially mediated by directly targeting to PTEN. Taken together, these evidences suggested that miR-144 may act as a promising therapeutic target for arterial restenosis

ReqGen: Keywords-Driven Software Requirements Generation

Software requirements specification is undoubtedly critical for the whole software life-cycle. Currently, writing software requirements specifications primarily depends on human work. Although massive studies have been proposed to speed up the process via proposing advanced elicitation and analysis techniques, it is still a time-consuming and error-prone task, which needs to take domain knowledge and business information into consideration. In this paper, we propose an approach, named ReqGen, which can provide further assistance by automatically generating natural language requirements specifications based on certain given keywords. Specifically, ReqGen consists of three critical steps. First, keywords-oriented knowledge is selected from the domain ontology and is injected into the basic Unified pre-trained Language Model (UniLM) for domain fine-tuning. Second, a copy mechanism is integrated to ensure the occurrence of keywords in the generated statements. Finally, a requirements-syntax-constrained decoding is designed to close the semantic and syntax distance between the candidate and reference specifications. Experiments on two public datasets from different groups and domains show that ReqGen outperforms six popular natural language generation approaches with respect to the hard constraint of keywords’ (phrases’) inclusion, BLEU, ROUGE, and syntax compliance. We believe that ReqGen can promote the efficiency and intelligence of specifying software requirements