Pyridine-borane complex-catalysed thioesterification: the direct conversion of carboxylic acids to thioesters.

Thioesters are a common class of biologically active fragments and synthetically useful building blocks. An attractive synthetic approach would be to use simple and bench-stable carboxylic acids as a coupling partner. Herein, we present a 4-bromo pyridine-borane complex as a catalyst for the direct coupling of carboxylic acids with thiols. A wide range of thioesters with good functional group compatibility could be prepared via this metal-free approach. The merit of this strategy is exemplified by the modification of carboxylic acid-containing drugs.

Revealing the reconstruction mechanism of AgPd nanoalloys under fluorination based on a multiscale deep learning potential.

The design of heterogeneous catalysts generally involves optimizing the reactivity descriptor of adsorption energy, which is inevitably governed by the structure of surface-active sites. A prerequisite for understanding the structure-properties relationship is the precise identification of real surface-active site structures, rather than relying on conceived structures derived from bulk alloy properties. However, it remains a formidable challenge due to the dynamic nature of nanoalloys during catalytic reactions and the lack of accurate and efficient interatomic potentials for simulations. Herein, a generalizable deep-learning potential for the Ag-Pd-F system is developed based on a dataset encompassing the bulk, surface, nanocluster, amorphous, and point defected configurations with diverse compositions to achieve a comprehensive description of interatomic interactions, facilitating precise prediction of adsorption energy, surface energy, formation energy, and diffusion energy barrier and is utilized to investigate the structural evolutions of AgPd nanoalloys during fluorination. The structural evolutions involve the inward diffusion of F, the outward diffusion of Ag in Ag@Pd nanoalloys, the formation of surface AgFx species in mixed and Janus AgPd nanoalloys, and the shape deformation from cuboctahedron to sphere in Ag and Pd@Ag nanoalloys. Moreover, the effects of atomic diffusion and dislocation formation and migration on the reconstructing pathway of nanoalloys are highlighted. It is demonstrated that the stress relaxation upon F adsorption serves as the intrinsic driving factor governing the surface reconstruction of AgPd nanoalloys.

The Mediating Role of Perceived Stress in Associations Between Self-Compassion and Anxiety and Depression: Further Evidence from Chinese Medical Workers.

OBJECTIVE: Medical workers report high rates of stress, anxiety and depression, which need urgent attention. Providing evidence for intervention measures in the face of a mental health crisis, the present study validates the relation between self-compassion and anxiety and depression mediated by perceived stress amongst medical workers. The goal is also to replicate a similar mediation model though multigroup analysis. METHODS: Medical workers were randomly selected to investigate by paper-and-pencil survey among 1,223 medical workers from three hospitals in Shiyan, China. The measures were comprised of four parts: the Chinese version of the Goldberg Anxiety and Depression Scale (GADS), the Self-Compassion Scale-Short Form (SCS-SF), the Perceived Stress Questionnaire (PSQ) and a socio-demographic questionnaire. Applying structural equation modeling (SEM, single-group analysis), we estimated the effects of self-compassion on anxiety/depression through perceived stress. Furthermore, based on multigroup analysis, we used two sets of internal samples (gender groups, medical groups) and an external sample (nursing students) for testing multigroup invariance. RESULTS: The average scores of anxiety, depression, self-compassion and perceived stress in medical workers were 5.93 ± 2.46, 4.91 ± 2.62, 38.87 ± 4.66 and 71.96 ± 15.14, respectively. In some departments engaged in the research, the medical workers showed higher levels of anxiety and depression. The SEM results indicated that the original relationship between self-compassion and anxiety and depression was beta = -0.42 (P < 0.001) and reduced to beta = -0.17 (P < 0.001) while introducing perceived stress as a mediating variable. Perceived stress was positively associated with anxiety and depression (beta = 0.60, P < 0.001), and self-compassion was negatively associated with perceived stress (beta = -0.56, P < 0.001). Multigroup analysis showed acceptable changes in fit indices across gender (male and female), medical (clinician and non-clinician), and population (medical workers and nursing students) groups. CONCLUSION: Medical workers were experiencing high levels of anxiety and depression and perceived stress. Perceived stress might have a partial mediating effect on self-compassion and anxiety and depression amongst medical workers, which was similar to a previous study in nursing students. The findings supported multigroup invariance across gender, medical and population groups. The study concluded that the mediation model may be generalized across these multiple samples. Psychological intervention could be used to improve levels of self-compassion of medical workers.

Correlation Between Platelet and Hemoglobin Levels and Pathological Characteristics and Prognosis of Early-Stage Squamous Cervical Carcinoma.

BACKGROUND We sought to determine the effect of pre-operative hemoglobin (HGB) and platelet (PLT) levels on the clinical features and prognosis of early-stage squamous cervical carcinoma (SCC). MATERIAL AND METHODS We performed a retrospective analysis of 380 patients with SCC who underwent hysterectomy and pelvic lymphadenectomy. SCC was confirmed post-operatively by pathological diagnosis. The relations between HGB and PLT levels and clinicopathological characteristics were observed, and a Cox regression analysis was performed to determine their influence on survival. RESULTS There were significant differences in tumor staging, tumor diameter, and lymphatic metastasis between the 69 patients with PLT levels >300×109/L and the 311 patients with PLT levels ≤300×109/L (P<0.05). Tumor staging, extent of differentiation, and lymphatic metastasis were significantly different between 134 patients with HGB levels <120 g/L and 246 patients with HGB levels ≥120 g/L (P<0.05). The overall survival rate in the group with PLT levels >300×109/L was lower than that in the group with PLT levels ≤300 × 109/L, but this difference was not significant. The overall survival rate in the group with HGB levels <120 g/L was significantly lower than that in the group with HGB levels ≥120 g/L (P<0.05), and the overall survival rate in the group with PLT levels >300×109/L and HGB levels <120 g/L was significantly lower than that in the group with PLT levels ≤300×109/L and HGB levels ≤120 g/L (P<0.05). According to Cox regression analysis, a pre-operative HGB level <120 g/L was considered a separate risk factor affecting prognosis. CONCLUSIONS Close attention must be paid to pre-operative PLT and HGB levels, and anemia should be remedied to facilitate the treatment of cervical carcinoma.

Facile preparation of beta-fluoro amines by the reaction of aziridines with potassium fluoride dihydrate in the presence of Bu4NHSO4.

Potassium fluoride combined with tetrabutylammonium bisulfate is an efficient reagent to convert a variety of aziridines derived from cyclic and acyclic alkenes to beta-fluoro amine derivatives in high yield.

A novel role of zeolite NaY in the thermal reaction of alkyl aryl selenoxides in its supercages.

Thermal reaction of alkyl aryl selenoxides in the presence of water or methanol in the supercage of zeolite NaY gave beta-hydroxy- or beta-methoxyalkyl aryl selenides, respectively, and NaY played a novel role to stabilize reactive ArSeOH and to separate an anion of -OH from a carbonium ion which was simultaneously present with the -OH in a supercage.