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A palladium-catalyzed asymmetric OH insertion reaction was developed. Palladium complexes with chiral spiro bisoxazoline ligands promoted the insertion of α-aryl-α-diazoacetates into the OH bond of phenols with high yield and excellent enantioselectivity under mild reaction conditions. This palladium-catalyzed asymmetric OH insertion reaction provided an efficient and highly enantioselective method for the preparation of synthetically useful optically active α-aryl-α-aryloxyacetates. [ABSTRACT FROM AUTHOR]

A discharge channel with a chamfered wall not only has application in the design of modern Hall thrusters, but also exists where the channel wall is eroded, and so is a common status for these units. In this paper, the laws and mechanisms that govern the effect of the chamfered wall on the performance of a Hall thruster are investigated. By applying both experimental measurement and particle-in-cell simulation, it is determined that there is a moderate chamfer angle that can further improve the optimal performance obtained with a straight channel. This is because the chamfering of the wall near the channel exit can enhance ion acceleration and effectively reduce ion recombination on the wall, which is favorable to the promotion of the thrust and efficiency. However, the chamfer angle should not be too large; otherwise, both the density of the propellant gas and the distribution of the plasma potential in the channel are influenced, which is undesirable for efficient propellant utilization and beam concentration. Therefore, it is suggested that the chamfer shape of the channel wall is an important factor that must be carefully considered in the design of Hall thrusters. [ABSTRACT FROM AUTHOR]

Tumor metastasis is the major cause of cancer-related death especially in human hepatocellular carcinoma (HCC). Although microRNAs have been implicated in tumor development, the roles of miR-124 in HCC metastasis are still not well understood. We conducted functional analysis in this study to investigate miR-124. We observed that miR-124 significantly retarded the wound healing and migration of HCC SMMC-7721 and BEL-7404 cells. Further analysis indicated miR-124 directly targeting the transcriptional factor Sp1 which is an important transcription factor for the integrin αV subunit gene transcription. Co-transfection of miR-124 with the luciferase reporter containing Sp1 3′ untranslated region (UTR) significantly suppressed the luciferase activities. While mutation of the binding site of miR-124 in Sp1 mRNA 3′UTR completely abrogated the suppression of miR-124. Overexpression of miR-124 resulted in robust downregulation of Sp1 and integrin αV expression at either mRNA or protein level. Ectopic expression of miR-124 in HCC dramatically repressed the wound healing and migration in vitro and tumor metastasis in mouse experiments. Our findings demonstrated that miR-124 played as an important role in regulation of integrin αV expression in HCC, and reintroduction of miR-124 might be an alternative therapeutic strategy for controlling integrin αV expression in HCC. [ABSTRACT FROM AUTHOR]

This method provides access to Boc-protected β,γ-unsaturated α-amino acid esters with excellent yields and enantioselectivities. [ABSTRACT FROM AUTHOR]

Background: As one of the leading causes of child mortality, deaths due to congenital anomalies (CAs) have been a prominent obstacle to meet Sustainable Development Goal 3.2., Objective: We conducted this study to understand the death burden and trend of under-5 CA mortality (CAMR) in Zhejiang, one of the provinces with the best medical services and public health foundations in Eastern China., Methods: We used data retrieved from the under-5 mortality surveillance system in Zhejiang from 2012 to 2021. CAMR by sex, residence, and age group for each year was calculated and standardized according to 2020 National Population Census sex- and residence-specific live birth data in China. Poisson regression models were used to estimate the annual average change rate (AACR) of CAMR and to obtain the rate ratio between subgroups after adjusting for sex, residence, and age group when appropriate., Results: From 2012 to 2021, a total of 1753 children died from CAs, and the standardized CAMR declined from 121.2 to 62.6 per 100,000 live births with an AACR of -9% (95% CI -10.7% to -7.2%; P<.001). The declining trend was also observed in female and male children, urban and rural children, and neonates and older infants, and the AACRs were -9.7%, -8.5%, -8.5%, -9.2%, -12%, and -6.3%, respectively (all P<.001). However, no significant reduction was observed in children aged 1-4 years (P=.22). Generally, the CAMR rate ratios for male versus female children, rural versus urban children, older infants versus neonates, and older children versus neonates were 1.18 (95% CI 1.08-1.30; P<.001), 1.20 (95% CI 1.08-1.32; P=.001), 0.66 (95% CI 0.59-0.73; P<.001), and 0.20 (95% CI 0.17-0.24; P<.001), respectively. Among all broad CA groups, circulatory system malformations, mainly deaths caused by congenital heart diseases, accounted for 49.4% (866/1753) of deaths and ranked first across all years, although it declined yearly with an AACR of -9.8% (P<.001). Deaths due to chromosomal abnormalities tended to grow in recent years, although the AACR was not significant (P=.90)., Conclusions: CAMR reduced annually, with cardiovascular malformations ranking first across all years in Zhejiang, China. Future research and practices should focus more on the prevention, early detection, long-term management of CAs and comprehensive support for families with children with CAs to improve their survival chances., (©Wen-Hong Dong, Jun-Xia Guo, Lei Wang, Shuang-Shuang Zheng, Bing-Quan Zhu, Jie Shao. Originally published in JMIR Public Health and Surveillance (https://publichealth.jmir.org), 03.06.2024.)

A palladium-catalyzed asymmetric O-H insertion reaction was developed. Palladium complexes with chiral spiro bisoxazoline ligands promoted the insertion of α-aryl-α-diazoacetates into the O-H bond of phenols with high yield and excellent enantioselectivity under mild reaction conditions. This palladium-catalyzed asymmetric O-H insertion reaction provided an efficient and highly enantioselective method for the preparation of synthetically useful optically active α-aryl-α-aryloxyacetates., (© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Oxidative stress has been proven to be involved in cisplatin (DDP)-induced toxicity. The aim of the present study was to investigate a possible protective role of grape seed proanthocyanidin extract (GSPE) in DDP-induced spermiotoxicity. GSPE at 200 mg kg(-1) d(-1) and 400 mg kg(-1) d(-1) was orally administered for 15 consecutive days, starting 10 days before a single intraperitoneal dose of DDP (7 mg kg(-1)). Results revealed that testicular and epididymal weight, epididymal sperm count, motility and morphology, the activities of GSH-Px and SOD, and GSH levels were significantly decreased whereas the level of MDA was significantly increased in the DDP group rats. GSPE treatment significantly attenuated the harmful effects of DDP-induced lipid peroxidation, oxidative stress, loss of genital organ weight, as well as function of reproductive organs. These changes were restored to near normal levels by GSPE at 400 mg kg(-1) d(-1). In conclusion, GSPE has dose dependent protective effects against DDP-induced rat testicular toxicity.