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关键词： Attenuation   Elastic constants   Mechanical parameters   Thermal conductivity  

摘要： The present paper reports investigation of elastic, mechanical, thermal, and ultrasonic features of B4 ternary alloy Ga_xAl_1-xN (0≤ x ≤ 1.0) at T = 300K. The second- and third-order elastic constants (SOECs and TOECs) were enumerated using the Lennard-Jones potential to judge the elastic stability of the selected alloys at 300 K. Pugh's ratio and Poisson's ratio show that all alloys display brittleness. The reducing trend of ultrasonic wave velocity with rising gallium concentration provides an indication of progressive lattice softening. The Debye characteristic temperature, thermal conductivity and relaxation time were assessed from elastic constants and ultrasonic velocities to explore the ultrasonic attenuation of the selected alloys. The semiconducting nature of the selected alloys has been confirmed by 10⁻¹¹ s order of the relaxation time. The machine learning algorithms, namely Random Forest and XGBoost have been utilized for comparative performance analysis across various statistical metrices. It is clear from the observed trends that XGBoost performs stable and better conditions in maximum situations, as manifest from the lower fault values and smoother differences.The scatter plot investigation provides information about the strong pact between forecasted and observed values. The theoretical results are in consistent with the existing computational and experimental data, validating the applied theoretical model.

关键词： Keggin-型杂多阴离子   质子化结构   光谱性质   密度泛函理论   遗传算法  

摘要： Keggin-型杂多酸作为高效光催化剂在能源催化转换领域扮演重要角色.虽然在实验上利用它们较为容易实现光催化反应,然而要对相关的光催化反应机理进行原子水平细节研究仍然困难重重,在其中获得一个相对合理的催化剂团簇模型至关重要.本文利用自建的遗传算法程序并结合密度泛函理论探究Keggin-型铌杂多阴离子完全质子化团簇(H_(n+3)[PMo_(12-n)Nb_(n)O_(40)],n=1~4)的稳定几何结构与光谱性质.通过观察铌作为杂原子取代团簇表面上的钼以及质子占据对体系几何结构和光谱性质的影响,我们期望能够为基于该类团簇的光催化剂分子设计以及光催化反应机理探究提供有用信息.基于计算数据,我们发现:在优化团簇几何结构中,随着杂Nb原子数目的增多,它们在团簇骨架上的分布能展现一定的规律(倾向于离散分布或者共用O桥而成等边三角形),并且质子均倾向于与杂Nb原子(或其邻居)相联的端基O成单键.团簇体系的偶极矩从最大值出发降到最低值而后逐渐增大.这可以被归功于杂原子铌与被取代原子钼之间相对较小的电负性差异以及取代位置模式的不同.研究体系的红外(或拉曼)吸收主要分布在两个波数区间(0~1500 cm^(-1))以及(3600~4000 cm^(-1)).前者对应于团簇骨架上重原子间(桥基O-Mo,O-Nb等)或者骨架局部关联的振动模式,后者对应于端基的O-H单键的振动模式.同时,它们在1200~1500cm^(-1)波数区间展现可区分的红外吸收分布,在高波数区间Raman吸收可展现强度差异.

关键词： Tributyltin   Histopathology   Ultrastructural adrenal structure   HMGB1/Beclin-1/NF-κB signals   Rats  

摘要：

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  TBT induces reversible adrenocortical toxicity via occurrence of hormonal disturbance in rats.
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  TBT results in oxidative stress, HMGB-1/ NF-κB signaling, and autophagy, with incomplete recovery after 4 weeks.
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  TBT results in histopathological, ultrastructural, and immunohistochemical alterations.
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  A 4-week recovery period partially reversed these changes.

关键词： 1,4-butanediol   Cu catalysts   Dehydrocyclization   Spinel structure   γ-butyrolactone  

摘要： Gas-phase dehydrocyclization of 1,4-butanediol (BDO) is an environmentally benign and sustainable route for γ-butyrolactone (GBL) production. In this work, a series of Cu-M (M = Zn, Cr) catalysts was synthesized via coprecipitation and evaluated in a fixed-bed reactor for GBL yield. Under the reaction conditions of 240 °C, 0.1 MPa, and a weight hourly space velocity (WHSV) of 2 mL∙g⁻¹∙h⁻¹, 99.62% of BDO conversion, 99.72% of GBL selectivity, and 2.22 mol_GBL·g_catalyst^-1·h⁻¹ of CBL formation rate were achieved over CuZnCr-600 catalyst, which is higher than reported studies. Long-term test proved that this catalyst could operate over 100 h without any deactivation. Combined microscopic and spectroscopic analysis showed that the calcination conditions affected the surface acidity-basicity of catalysts by changing the CuO content and the strength of the Cr-O bond. The Cu-M compositions significantly influenced the morphology and the electronic properties of Cu species. The incorporation of Cr led to the formation of CuCr₂O₄ spinel structure, which not only enhanced Cu dispersion but also improved the catalysts’ resistance to sintering. The presence of Zn restrained the phase-transformation of CuCr₂O₄ from cubic to tetragonal, which ensured the reducible property of CuCr₂O₄ even under high-temperature calcination. Furthermore, modulating the calcination temperature and the Cu-M compositions maintained an optimal Cu⁺/Cu⁰ ratio under reaction conditions. All these issues contributed to the high yield of GBL and the prolonged lifetime of catalysts.

关键词： Lactic acid bacteria(LAB)   Whole genome analysis   Non-ribosomal peptide synthetase(NRPS)   Green fluorescent protein(gfp)   Probiotics   Antimicrobial properties  

摘要： Lactic acid bacteria(LAB)are important probiotics and also an important source of biological preservatives for preventing foodborne diseases.This study isolated Lactiplantibacillus plantarum 3-1 from traditional Chinese pickles,which exhibited excellent broad-spectrum antibacterial activity,auto-aggregation ability(26.30%±1.44%),cell surface hydrophobicity(4.37%±0.77%),and safety among selected strains.Whole-genome sequencing identified a novel gene cluster encoding non-ribosomal peptide synthetase(NRPS),which serve as the genetic basis for the enhanced antibacterial activity of its fermentation supernatant.Transcriptome sequencing and a green fluorescent protein(gfp)-based promoter reporter system further confirmed the expression of this NRPS gene cluster.Optimization of the culture conditions(pH 6.0,0.4 mol/L sucrose,4%w/v NaCl)enhanced NRPS expression,as evidenced by a 3.65-fold and 2.10-fold increase in the antibacterial activity of the fermentation supernatant against Staphylococcus aureus and Escherichia coli,respectively.Then the crude NRPS-derived antimicrobial substances extract from the optimized culture effectively inhibited the growth of pathogenic bacteria in milk.In a word,this study highlights the potential probiotic properties of L.plantarum 3-1 and its NRPS-derived antibacterial compounds as effective bio-preservatives in the food industry.

摘要： The author would like to report the following updates and clarifications to the published version of the above-mentioned article. These revisions are intended to enhance the clarity, accuracy, and interpretation of the reported results, mainly in Section 9.3. Importantly, these updates do not affect the conclusions of the study. The evaluation metrics are clarified to explicitly indicate that weighted precision, weighted recall, and weighted F1-score are used. Accordingly, the last paragraph of Section 8.1.2 has been revised as follows:. © 2026 Elsevier B.V. All rights are reserved, including those for text and data mining, AI training, and similar technologies.

关键词： Gas sensors   Density functional theory   CdS monolayer   Dissolved gases in oil  

摘要： Safe and stable operation of oil-immersed transformers is essential for ensuring the reliable power supply of electrical systems. Internal faults in these transformers release characteristic dissolved gases such as CO, CO2, and C2H2;therefore, the effective detection of these gases is of great significance for early warning of transformer faults. In this study, based on first-principles calculations, we investigated the adsorption and sensing properties of Cu-cluster-modified Cadmium sulfide (CdS) monolayers toward the aforementioned three characteristic gases. The results indicate that the introduction of copper clusters effectively modulates the electronic structure of the CdS monolayer and significantly enhances the system's electronic transport capabilities. Analysis of adsorption performance reveals that the Cu1-CdS system exhibits weak interaction with the target gases, whereas the Cu2-CdS and Cu3-CdS systems demonstrate strong chemical adsorption capabilities for both CO and C2H2, accompanied by significant charge transfer and orbital hybridization;however, the adsorption intensity for CO2 remains low across all modified systems. Finally, based on sensitivity and recovery time analyses, it was found that the Cu2-CdS monolayer exhibits the optimal sensing capability for C2H2 gas, with a sensitivity of 16.48 and a recovery time as short as 29.12 s at 348 K, enabling highly sensitive and repeatable detection of C2H2 gas. This study provides a theoretical basis for the development of novel gas sensors for transformer fault early warning, so as to provide insights for the design of such gas sensors in the future.

关键词： 假性甲状旁腺功能减退症   低钾血症   低钙血症  

摘要： 1病例介绍患者女,38岁,于2023-08-16因“间断头晕10年,加重伴发现低血钾1月余”至河北北方学院附属第一医院内分泌科就诊。2022-08起患者间断出现手足抽搐,伴头晕,曾服中药(具体不详),症状反复。

关键词： nonlinear acoustics   thermoviscoelasticity   small-data solution   decay rate 2020 MSC35B40 (primary)   35L05   35B35 (secondary)  

摘要： In bounded n-dimensional domains with n ≥ 1, this manuscript examines an initial-boundary value problem for the system

来源 ScienceDirectJournal ScienceCitationIndex... 详细信息