303 research outputs found
Social trust and subjective well-being of first-generation college students in China: the multiple mediation effects of self-compassion and social empathy
Previous studies have found that subjective well-being is associated with social trust, self-compassion, and social empathy. Based on online fieldwork with 662 first-generation college students (54.7% male) in China, this study aimed to investigate the serial mediation effects of self-compassion and social empathy on the relationship between social trust and subjective well-being. The results showed that subjective well-being was significantly positively correlated with social trust, trust in people, self-compassion, and social empathy. Both self-compassion and social empathy partially mediated the relationship between social trust and subjective well-being, and fully mediated the association between trust in people and subjective well-being. We used a serial mediation model to estimate the effect of general social trust, including trust in people, on subjective well-being. The findings that self-compassion and social empathy mediated the relationship between trusting attitudes toward society, especially people, and subjective well-being expand the literature on social trust and the mechanism of social trust on subjective well-being. The results also highlight the significance of improving mental health education and intervention among first-generation college students in China
Study of muon tomographic imaging for high Z material detection with a Micromegas-based tracking system
A high spatial resolution tracking system was setup with the Micro-mesh
gaseous structure (Micromegas) detectors in order to study the muon tomographic
imaging technique for nuclear threat detection. 6 layers of 90 mm 90
mm one-dimensional readout Micromegas were used to construct a tracking system
and the imaging test using some metallic bars was performed with cosmic ray
muons. A two-dimensional imaging of the test object was presented with a newly
proposed ratio algorithm
Evaluation of Fermentation Dynamics and Structural Carbohydrate Degradation of Napiergrass Ensiled with Additives of Urea and Molasses
This study examined the effects of urea and molasses on fermentation dynamics and structural carbohydrate degradation of Napiergrass (Pennisetum purpureum Schumach), which was ensiled in laboratory silos for 3, 7, 14, and 30 days at the ambient temperature. The treatments were additions (fresh weight basis) of: no molasses or urea (control), no molasses and 0.4% urea (U), 4% molasses and 0% urea (M), 4% molasses and 0.4% urea (MU). The results showed that the control group produced an unstable fermentation. U silage always had smallest amount of lactic acid and highest levels of pH, acetic acid, butyric acid and ammonia nitrogen. Compared with control, both M and MU increased water soluble carbohydrate contents which promoted lactic acid fermentation domination, but MU did not restrain clostridial fermentation. After 30 days of ensiling, compared with the control, both M and MU lowered structural carbohydrate contents, and U lowered crude protein content but MU increased this parameter. It was concluded that the combination of 4% molasses with 0.4% urea could improve the fermentation and nutritive qualities of Napiergrass but was not sufficient to inhibit clostridial fermentation
[1,1′-Bis(diphenylphosphino)cobaltocenium-κ2 P,P′]dichloridoplatinum(II) hexafluoridophosphate
The title bimetallic compound, [PtCl2{Co(C17H14P)2}]PF6, was obtained by reaction of 1,1′-bis(diphenylphosphino)cobaltocenium hexafluoridophosphate with bis(acetonitrile)dichloridoplatinum. The PtII ion is four-coordinated in a slightly distorted square-planar environment by two P atoms of the 1,1′-bis(diphenylphosphino)cobaltocenium moiety and two Cl atoms. In the crystal structure, molecules are linked by weak C—H⋯F and C—H⋯Cl hydrogen bonds
Non-Gaussianity in the warm k-inflation
This paper presents and investigates non-Gaussian perturbations for the warm
k-inflation model that is driven by pure kinetic energy. The two complementary
components of the overall non-Gaussianity are the three-point and four-point
correlations. The intrinsic non-Gaussian component, denoted as the nonlinear
parameter f_{NL}^{int}, is rooted in the three-point correlation for the
inflaton field. Meanwhile, the \delta N part non-Gaussianity, denoted as
f_{NL}^{\delta N}, is the contribution attributed to the four-point correlation
function of the inflaton field. In this paper, the above two components in warm
k-inflation are individually computed and analyzed. Then, comparisons and
discussions between them are conducted, and the non-Gaussian theoretical
results are compared with experimental observations to determine the range of
model parameters within the allowable range of observation
Restoration of mutant K-Ras repressed miR-199b inhibits K-Ras mutant non-small cell lung cancer progression
Background: miRNAs play crucial role in the progression of K-Ras-mutated nonsmall cell lung cancer (NSCLC). However, most studies have focused on miRNAs that target K-Ras. Here, we investigated miRNAs regulated by mutant K-Ras and their functions. Methods: miRNAs regulated by mutant K-Ras were screened using miRNA arrays. miR-199b expression levels were measured by qRT-PCR. The protein expression levels were measured using Western blot and immunohistochemistry. The effects of miR-199b on NSCLC were examined both in vitro and in vivo by overexpressing or inhibiting miR-199b. DNA methylation was measured by bisulfite sequencing. Results: An inverse correlation was observed between K-Ras mutation status and miR-199b levels in NSCLC specimens and cell lines. The inhibition of miR-199b stimulated NSCLC growth and metastasis, while restoration of miR-199b suppressed K-Ras mutation-driven lung tumorigenesis as well as K-Ras-mutated NSCLC growth and metastasis. miR-199b inactivated ERK and Akt pathways by targeting K-Ras, KSR2, PIK3R1, Akt1, and Rheb1. Furthermore, we determined that mutant K-Ras inhibits miR-199b expression by increasing miR-199b promoter methylation. Conclusion: Our findings suggest that mutant K-Ras plays an oncogenic role through downregulating miR-199b in NSCLC and that overexpression of miR-199b is a novel strategy for the treatment of K-Ras-mutated NSCLC.This work was supported by the National Natural Science Foundation of China (81672283 to H.J.) and the Startup Fund for Talented Scholars of Daping Hospital and Research Institute of Surgery, Third Military Medical University (to H.J. and C.-X.X).
In situ probing electrified interfacial water structures at atomically flat surfaces using Raman spectroscopy
自然界中水无处不在,人们对水分子的研究已经长达一个多世纪。特别是在材料表面,从原子结构层面理解界面水所发生的各种物理和化学过程,将有利于指导能源和环境领域中开发更好的技术和器件。文献中采用振动光谱已经推知了水在金属界面的不同构型,如四配位水、三配位水、表面特性吸附水、自由水等。然而,仍然缺乏这些界面水在不同电位下清晰的构型图像。李剑锋教授课题组采用不受体相水干扰的表面增强拉曼光谱,首次在金(111)和(100)单晶电极表面上获得了界面水的拉曼信号,并且在析氢反应过程中原位观测到了界面水的两种构型转变。发现界面水随着电位的负移,由“平行”结构向“单端氢朝下”,再向“双端氢朝下”变化。程俊教授课题组采用从头算分子动力学理论方法,模拟出不同电位下,在双电层中界面水的三种构型以及相应的氢键数目,与实验数据很好地吻合,进一步揭示了双电层的原子级结构。该研究首次在实验和理论层面,将界面水的构型转变以及氢键断裂与精确的电极电势标尺进行关联,对探知双电层的三维结构具有指导性意义。
该研究工作通过厦门大学校内合作完成,化学化工学院李剑锋教授和程俊教授为通讯作者,田中群教授提供了重要指导。李超禹博士(现美国麻省理工学院博士后)和乐家波博士(现能源材料化学协同创新中心博士后)为共同第一作者,王耀辉博士生在实验上提供了帮助,物理系的陈舒博士和杨志林教授为本工作开展了电磁场增强计算【Abstract】Molecular structures of solid/liquid interfaces are of fundamental interest, and play significantly in the efficiencies of energy storage and conversion. To elucidate the structures of electric double layers at electrochemical interfaces under bias potentials, we have collaborated in situ Raman spectroscopy and ab initio molecular dynamics, and for the first time distinguished two structural transitions of interfacial water at electrified Au(111) and Au(100) single crystal electrode surfaces. Towards negative potentials, the interfacial water molecules evolve from structurally “parallel” to “one-H-down”, and further to “two-H-down”.Concurrently, the number of hydrogen bonds among the interfacial water shows an overall decrease along with the negative shift of the potential, and undergoes two transitions as well. Our findings shed light on fundamental understanding of electric double layers and electrochemical processes at the interfaces.National Natural Science Foundation of China (Grants No. 21373166, 21522508,
21775127, 21521004, 21321062 and 21621091).
该工作得到国家自然科学基金委的大力资助,也得到了固体表面物理化学国家重点实验室、谱学分析与仪器教育部重点实验室、能源材料化学协同创新中心的支持
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