Fossil bovids are key components of the Neogene mammal faunas in Eurasia, showing high diversity and rapid rates of evolution, with important implications for biostratigraphy and understanding past ...climate change. The Linxia Basin (Gansu Province, China) contains rich Miocene to Early Pleistocene bovid assemblages that provide an opportunity to study the evolution of this group. This paper reviews the fossil record of bovids in the Linxia Basin, which comprises more than 20 genera within seven tribes, spanning nine stratigraphic horizons and distributed across 43 fossil localities. Findings show that the diversity of fossil bovids in the Linxia Basin increased dramatically from the Early to Late Miocene but fell suddenly at the end of the Late Miocene before reaching a second peak in the Early Pleistocene. The Late Miocene mammal assemblages from the Linxia Basin may indicate somewhat younger age than previously thought based on fossil bovid comparisons. With diverse species and rich material, the bovids of the Linxia Basin present an excellent opportunity for further studies on morphology and adaptations within the group.
•Linxia fossil bovids from 9 fossiliferous layers comprise over 20 genera (7 tribes).•The Linxia Dashengou Fauna shares similar bovids with Lamagou and Bahe.•Yangjiashan Fauna shares bovids with the Hipparion faunas of Baode and Qingyang.•There is chronological overlap of some faunas.
College graduates face increasing employment pressure due to the continuous expansion of colleges and universities' enrollment scales. It highlights the shortcomings of college students' ...employability, and these deficiencies can be improved and enhanced through the role of ideological and political education. Firstly, this paper summarizes the current situation of college students' employment management at this stage and finds countermeasures to improve their employability to help them correctly understand their employment situation. Secondly, the reasons for the lack of ideological and political education in cultivating college students' employability are emphasized to clarify the relationship between ideological and political education and college students' employment management. Besides, specific suggestions are put forward on the issue of cultivating college students' employability. Finally, the deep learning (DL) recommendation model is used to effectively connect the correlation between student data and enterprise information to improve the employment rate and employment satisfaction of colleges and universities, and the two are jointly trained. The experimental results show that: (1) The proposed model can mine the characteristics of students and enterprises and conduct feature interaction with a good hit rate. (2) The proposed model can interact with the two tasks and mine the relationship information to improve the performance of the recommended task. This paper aims to use DL methods to analyze and construct the portrait of college students' employability needs and study the accurate recommendation system based on the employment matching degree of college students to improve employment management and ideological and political education methods.
Electrochemical reduction of nitrogen to produce ammonia at moderate conditions in aqueous solutions holds great prospect but also faces huge challenges. Considering the high selectivity of Au‐based ...materials to inhibit competitive hydrogen evolution reaction (HER) and high activity of transition metals such as Fe and Mo toward the nitrogen reduction reaction (NRR), it was proposed that Au‐based alloy materials could act as efficient catalysts for N2 fixation based on density functional theory simulations. Only on Mo3Au(111) surface the adsorption of N2 is stronger than H atom. Thermodynamics combined with kinetics studies were performed to investigate the influence of composition and ratio of Au‐based alloys on NRR and HER. The binding energy and reorganization energy affected performance for the initial N2 activation and hydrogenation process. By considering the free‐energy diagram, the computed potential‐determining step was either the first or the fifth hydrogenation step on metal catalysts. The optimum catalytic activity could be achieved by adjusting atomic proportion in alloys to make all intermediate species exhibit moderate adsorption. Free‐energy diagrams of N2 hydrogenation via Langmuir‐Hinshelwood mechanism and hydrogen evolution via Tafel mechanism were compared to reveal that the Mo3Au surface showed satisfactory catalytic performance by simultaneously promoting NRR and suppressing HER. Theoretical simulations demonstrated that Au‐Mo alloy materials could be applied as high‐performance electrocatalysts for NRR.
Electrocatalytic nitrogen reduction reaction: The influences of composition and ratio of Au‐based alloys on the catalytic activity and selectivity of electrochemical nitrogen reduction reaction (NRR) are investigated by theoretical calculations of electronic structures, thermodynamics, and reaction kinetics. Among all the studied bimetallic catalysts, Mo3Au(111) shows the best electrocatalytic performace by promoting NRR and suppressing hydrogen evolution.
A novel
alkaloid, lycocasine A (
), and seven known
alkaloids (
-
), were isolated from
. Their structures were determined through NMR, HRESIMS, and X-ray diffraction analysis. Compound
features an ...unprecedented 5/6/6 tricyclic skeleton, highlighted by a 5-aza-tricyclic6,3,1,0
dodecane motif. In bioactivity assays, compound
demonstrated weak inhibitory activity against acid-sensing ion channel 1a.
Fluorescent carbon dots (CDs) with narrow emissions have been mostly prepared at high temperatures and high pressures, with long reaction times and tedious purification processes, which greatly ...limits their large-scale production. In contrast, the microwave-assisted solvothermal method can produce CDs simply and rapidly, but often results in wide-emissive CDs with full widths at half maximum (FWHM) larger than 80 nm. In this study, the microwave synthesis of CDs was improved by using ethylene glycol as the solvent and sodium thiosulfate as the oxidant. Consequently, narrow emissive CDs with a FWHM of only 35 nm were obtained from phloroglucinol, and were purified by simple precipitation using a mixed solvent of ethanol and dichloromethane. The structural characterization studies of the obtained CDs reveal that the sulfur element could be doped in the carbon structure with the addition of thiosulfate. It was also demonstrated that the photoluminescence efficiency of the CDs is greatly determined by their carbon core structures and edge groups. In addition, the fluorescence of CDs could be tuned significantly from the blue region to the green region by changing the dispersing solvent. Accordingly, the prepared CDs were successfully applied for the sensing of water content in organic solvents.
Fluorescent carbon dots with narrow emissions were simply synthesized by open microwave-heating of ethylene glycol solution of phloroglucinol and thiosulfate.
People with serious mental illness are at great risk of suicide, but little is known about the suicide rates among this population. We aimed to quantify the suicide rates among people with serious ...mental illness (bipolar disorder, major depression, or schizophrenia).
PubMed and Web of Science were searched to identify studies published from 1 January 1975 to 10 December 2020. We assessed English-language studies for the suicide rates among people with serious mental illness. Random-effects meta-analysis was used. Changes in follow-up time and the suicide rates were presented by a locally weighted scatter-plot smoothing (LOESS) curve. Suicide rate ratio was estimated for assessments of difference in suicide rate by sex.
Of 5014 identified studies, 41 were included in this analysis. The pooled suicide rate was 312.8 per 100 000 person-years (95% CI 230.3-406.8). Europe was reported to have the highest pooled suicide rate of 335.2 per 100 000 person-years (95% CI 261.5-417.6). Major depression had the highest suicide rate of 534.3 per 100 000 person-years (95% CI 30.4-1448.7). There is a downward trend in suicide rate estimates over follow-up time. Excess risk of suicide in males was found 1.90 (95% CI 1.60-2.25). The most common suicide method was poisoning 21.9 per 100 000 person-years (95% CI 3.7-50.4).
The suicide rates among people with serious mental illness were high, highlighting the requirements for increasing psychological assessment and monitoring. Further study should focus on region and age differences in suicide among this population.
The electrochemical reduction of CO2 is a promising route for converting intermittent renewable energy into storable fuels and useful chemical products. A theoretical investigation of the reaction ...mechanism and kinetics is beneficial for understanding the electrocatalytic activity and selectivity. In this report, a kinetic model based on Marcus theory is developed to compute the potential-dependent reaction barrier of the elementary concerted proton–electron transfer steps of electrochemical CO2 reduction reactions, different from the previous hydrogen atom transfer model. It is found that the onset potentials and rate-determining steps for CO and CH4 formation are determined by the first and third concerted proton–electron transfer steps C1 and C3. The influence of binding energy, electrode potential, and reorganization energy on the computed reaction barriers of the C1 and C3 reactions is discussed. In general, the calculated reaction barrier shows a quadratic relationship with the applied electrode potential. Specifically, the reaction barrier is merely determined by the reorganization energy at equilibrium potential. The present kinetic model is applied to compare the electrocatalytic activities in the electrochemical reduction of CO2 on various copper crystal surfaces. Among the four studied copper single-crystal surfaces, Cu(211) exhibits the best electrocatalytic activity for CO formation and CH4 formation due to its low onset potential and overpotential.
Taxodin A (1), a unique C30 terpenoid featuring an unprecedented skeleton composed of an abietane‐type diterpene and a menthane‐type monoterpene, was obtained from the leaves and branches of Taxodium ...mucronatum. The structure and absolute configuration of compound 1 was unequivocally established by the combination of extensive spectroscopic analyses and X‐ray single‐crystal diffraction analysis. Compound 1 exhibited potent cytotoxic activities against A549, SMMC‐7721, MDA‐MB‐231, and SW480 cell lines with IC50 values of 15.35±0.73, 8.49±0.35, 17.53±0.79, 18.93±0.60 μM, respectively.
Voltage‐gated calcium channels (VGCCs), particularly T‐type calcium channels (TTCCs), are crucial for various physiological processes and have been implicated in pain, epilepsy, and cancer. Despite ...the clinical trials of TTCC blockers like Z944 and MK8998, none are currently available on the market. This study investigates the efficacy of Lycopodium alkaloids, particularly as natural product‐based TTCC blockers. We synthesized eighteen derivatives from α‐obscurine, a lycodine‐type alkaloid, and identified five derivatives with significant Cav3.1 blockade activity. The most potent derivative, compound 7, exhibited an IC50 value of 0.19±0.03 μM and was further analyzed through molecular docking, revealing key interactions with Cav3.1. These findings provide a foundation for the structural optimization of Cav3.1 calcium channel blockers and present compound 7 as a promising lead compound for drug development and a tool for chemical biology research.
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