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Resveratrol, an activator of SIRT1, restores erectile function in streptozotocin-induced diabetic rats

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Asian Journal of Andrology 2013年第5期15卷 646-651页

作者： Wen yu Zan Wan Xue-Feng Qiu yun chen yu-tian Dai Department of Urology Affiliated Drum Tower Hospital School of Medicine Nanjing University Nanjing 210008 China

The high incidence of erectile dysfunction （ED） in diabetes highlights a need for effective treatment strategies. Resveratrol, an activator of silent information regulator 2-related enzymes 1 （sirtuinl, SIRT1）, has received attention for its valuable effects in cancer, neurodegenerative diseases, longevity and cardiovascular disease. To explore the effects of resveratrol in diabetes-induced ED, resveratrol was administered to rats with streptozocin （65 mg kg-1）-induced diabetes. Erectile function, cavernous structure, tissue protein expression of silent information regulator 2-related enzymes 1 （sirtuinl, SIRT1）, p53 and forkhead transcription factor 0 3a （FOXO3a）, superoxide dismutase （SOD） activity and malondialdehyde （MDA） levels in the corpora cavernosa were studied. We found that SIRT1 was expressed in cavernosal tissue, and it was downregulated in the corpora of diabetic rats. The administration of resveratrol upregulated the expression of SI RT1 and restored erectile function. In contrast, resveratrol downregulated the expression of p53 and FOXO3a, which regulate apoptosis and oxidative stress. Furthermore, the resveratrol-treated group showed an improvement in smooth muscle content, SOD activity and MDA levels when compared with the diabetic group. Therefore, the ability of resveratrol to improve diabetes-induced ED is likely related to its activation of SIRT1 expression, thus causing the suppression of apoptosis and resistance towards oxidative stress.

关键词： apoptosis erectile dysfunction oxidative stress resveratrol

Tunable plasmon-induced transparency based on asymmetric H-shaped graphene metamaterials

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Chinese Physics B 2018年第12期27卷 297-303页

作者： yu-chen tian Wei Jia Pei-Wen Ren Chun-Zhen Fan School of Physical Science and Engineering Zhengzhou University

We propose and numerically demonstrate a tunable plasmon-induced transparency(PIT) phenomenon based on asymmetric H-shaped graphene metamaterials. The tunable PIT effect is realized through varying the applied polarization angles rather than changing the structure geometry. By simply adjusting the polarization angle, the transmission spectra can be controlled between the switch-on state and switch-off state. The physical mechanism of the induced transparency is revealed from magnetic dipole inductive coupling and phase coupling. Importantly, by varying the Fermi energy of the graphene or the refractive index of the substrate, the resonant position of the PIT can be dynamically controlled and the maximum modulation depths can reach up to 60.7%. The sensitivity(nm/RIU) of the graphene structure, which is the shift of resonance wavelength per unit change of refractive index, is 5619.56 nm/RIU. Moreover, we also extend our research to the x-axis symmetric H-shaped structure, and the tunable PIT transmission window can also be realized. The physical mechanism of the induced transparency is revealed from the electric dipole hybridization coupling. Our designed H-shaped graphene-based structures is a promising candidate for compact elements such as tunable sensors, switches and slow-light devices.

关键词： plasmon-induced transparency graphene polarization optical filter

Dynamically tunable optical properties in graphene-based plasmon-induced transparency metamaterials

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Chinese Physics B 2019年第2期28卷 363-368页

作者： Wei Jia Pei-Wen Ren yu-chen tian Chun-Zhen Fan School of Physical Science and Engineering Zhengzhou University

A graphene-based metamaterial for THz plasmon induced transparency(PIT) is presented and numerically studied in this paper, which consists of two horizontal graphene strips attached to a continuous vertical wire separately. The calculated surface current distributions demonstrate that the distinct PIT window results from the near-field coupling of two bright modes. To explore the physical mechanism of PIT effect, we employ the coupled Lorentz oscillator model. The transmission spectra obtained with this model fits well with the simulation results. The performance of the PIT system can be controlled through the geometry parameters of graphene strips. Moreover, the transparency window can be dynamically tuned by varying the Fermi energy and the carrier mobility of the graphene strips. The slow light effect is also explored in our proposed structure and it can achieve 1.25 ps when Fermi energy is 1.3 eV. Finally, the position of the transmission window with the variation of the nearby medium refractive index is examined. Such a proposed graphene-based PIT system may have great potential applications in photonic devices.

关键词： plasmon-induced transparency graphene tunable

Evaluation and attribution of trends in compound dry-hot events for major river basins in China

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Science China Earth Sciences 2024年第1期67卷 79-91页

作者： Shaotang XIONG Tongtiegang ZHAO chengchao GUO yu tian Fang YANG Wenlong chen Xiaohong chen Key Laboratory of Water Security Guarantee in Guangdong-Hong Kong-Marco Greater Bay Area of Ministry of Water Resources&Sun Yatsen University/Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai) Guangzhou 510275China China Institute of Water Resource and Hydropower Research Beijing 100038China Pearl River Hydraulic Research Institute Guangzhou 510611China

Concurrent compound dry and hot events(CDHEs)amplified more damange on the ecosystems and human society than individual *** climate change,compound dry and hot events become more frequent on a global *** paper proposes a mathematical method to quantitatively attribute changes of CDHEs to changes of precipitation,change in temperature and change in the dependence between precipitation and *** attribution is achieved by formulating the total differential equation of the return period of CDHEs among Meta-gaussian model.A case study of China is devised based on monthly precipitation and temperature data during the period from 1921 to 2020 for 80 major river *** is found that temperature is the main driving factor of increases in CDHEs for 49 major river basins in China,except for the upper and middle reaches of the Yangtze *** West China,precipitation changes drove the increase in CDHEs in 18 river basins(23%),particularly in parts of North Xinjiang,Qinghai and *** the other hand,dependence between precipitation and temperature dominated changes of CDHEs in 13 river basins(16%)of China with other factors,including parts of South China,East China and Northwestern ***,changes in both the mean and spread of precipitation and temperature can also contribute to changes in CDHEs.

关键词： Climate extreme Compound dry and hot extreme Precipitation Temperature Return period

Soil disturbance evaluation of soft clay based on stress-normalized smallstrain stiffness

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第3期16卷 990-999页

作者： Yanguo Zhou yu tian Junneng Ye Xuecheng Bian yunmin chen MOE Key Laboratory of Soft Soils and Geoenvironmental Engineering Institute of Geotechnical EngineeringCenter for Hypergravity Experiment and Interdisciplinary ResearchZhejiang UniversityHangzhou310058China Ningbo Rail Transit Group Co. Ltd.Ningbo315010China

Soil disturbance includes the change of stress state and the damage of soil *** field testing indices reflect the combined effect of both changes and it is difficult to identify the soil structure disturbance directly from these *** the present study,the small-strain shear modulus is used to characterize soil structure disturbance by normalizing the effective stress and void ratio based on Hardin *** procedure for evaluating soil sampling disturbance in the field and the further disturbance during the subsequent consolidation process in laboratory test is proposed,and then validated by a case study of soft clay *** seismic testing in the field,portable piezoelectric bender elements for the drilled sample and bender elements in triaxial apparatus for the consolidated sample were used to monitor the shear wave velocity of the soil from intact to disturbed and even remolded *** is found that soil sampling disturbance degree by conventional thin-wall sampler is about 30%according to the proposed procedure,which is slightly higher than that from the modified volume compression method proposed by Hong and Onitsuka(1998).And the additional soil disturbance induced by consolidation in laboratory could reach about 50%when the consolidation pressure is far beyond the structural yield stress,and it follows the plastic volumetric strain quite well.

关键词： Natural clay Soil sample disturbance Shear wave velocity Small-strain shear modulus Hardin equation

Mitigated lattice distortion and oxygen loss of Li-rich layered cathode materials through anion/cation regulation by Ti^(4+)-substitution

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Chinese Chemical Letters 2024年第2期35卷 548-552页

作者： Kaicheng Zhang yu tian Xuanjin chen Shan Hu Zelang Jian State Key Laboratory of Advanced Technology for Materials Synthesis and Processing School of Materials Science and EngineeringWuhan University of TechnologyWuhan 430070China

Lithium-rich layered cathode material(LLM)can meet the requirement of power lithium-ion energy storage devices due to the great energy ***,the de/intercalation of Li+will cause the irreversible loss of lattice oxygen and trigger transition metal(TM)ions migrate to Li+vacancies,resulting in capacity *** we brought Ti4+in substitution of TM ions in Li_(1.2)Mn_(0.54)Ni_(0.13)Co_(0.13)O_(2),which could stabilize structure and expand the layer spacing of ***,optimized Ti-substitution can regulate the anions and cations of LLM,enhance the interaction with lattice oxygen,increase Ni^(3+) and Co^(3+),and improve Mn^(4+) coordination,improving reversibility of oxygen redox activation,maintaining the stable framework and facilitating the Li^(+) ***,we found 5%Ti-substitution sample delivered a high discharge capacity of 244.2 mAh/g at 50 mA/g,an improved cycling stability to 87.3%after 100 cycles and enhanced rate *** Ti-substitution gives a new pathway to achieve high reversible cycle retention for LLMs.

关键词： Lithium-rich layered cathode material Ti-substitution Anion/cation regulation Structural stability Cycling stability

Enhancing reversible hydrogen storage performance of 2LiBH_(4)–MgH_(2)via in-situ building heterogeneous nucleation sites

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Rare Metals 2024年第9期43卷 4367-4376页

作者： Wei chen Ya-Hui Sun tian Xu Xue-Bin yu Guang-Lin Xia Department of Materials Science Fudan UniversityShanghai 200433China

2LiBH_(4)-MgH_(2)composite is one of the most attractive reactive hydride composites with a theoretic hydrogen capacity of 10.8 wt%.However,the large nucleation restriction of MgB_(2)during the second step of dehydrogenation results in sluggish hydrogen storage kinetics and high operating temperature,which hinders its practical application as on-board hydrogen storage ***,Al3Ti doped Al nanoparticles(AT NPs)are prepared by a facile chemical reduction reaction to improve the hydrogen storage performance of 2LiBH_(4)-MgH_(2)*** the initial H_(2)desorption process,MgAlB_(4)and TiB_(2)that have identical crystal structure and low d-value mismatch with MgB_(2)resulting from the reaction between AT NPs and 2LiBH_(4)-MgH_(2)composite serve as effective nucleation sites for the formation of MgB_(2).As a result,the apparent activation energy of the two-step H_(2)desorption of AT NPs doped 2LiBH_(4)-MgH_(2)composite are notably decreased to(110.0±5.9)and(119.6±1.4)kJ·mol^(-1),which is 55.5 and 33.5 kJ·mol^(-1)lower than that of the undoped *** importantly,a reversible hydrogen storage capacity of 9.2 wt%after 10cycles of H_(2)desorption and adsorption could be achieved,corresponding to a capacity retention rate of 99%.The building of reactive bimetallic catalyst towards in situ formation of heterogeneous nucleation sites provides a new strategy for improving the hydrogen storage performance of reactive hydride composites.

关键词： Reversible hydrogen storage Reactive hydride composites Catalytic effects Heterogeneous nucleation

Understanding the cooperative effects in the catalysis of homodimeric fluoroacetate dehalogenase

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Science China Chemistry 2024年第7期67卷 2382-2391页

作者： Ke-Wei chen Jia-Nan chen Jun Zhang Chao Wang tian-yu Sun yun-Dong Wu Key Laboratory of Computational Chemistry and Drug Design State Key Laboratory of Chemical OncogenomicSchool of Chemical Biology and BiotechnologyPeking University Shenzhen Graduate SchoolShenzhen 518055China Institute of Chemical Biology Shenzhen Bay LaboratoryShenzhen 518132China College of Chemistry and Molecular Engineering Peking UniversityBeijing 100871China Changping Laboratory Beijing 102200China

Fluoroacetate dehalogenases(FAcD),a homodimeric enzyme,catalyzes the conversion of fluoroacetic acid to glycolic acid(GoA).It has been proved that the enzyme has a half-of-the-site ***,its catalytic(C)subunit converts the first substrate to a covalent intermediate;then,the non-catalytic(NC)subunit binds a second substrate and promotes the conversion of the intermediate in the C subunit into the final *** the release of the product,the C subunit becomes the NC subunit,and the previous NC subunit becomes the C *** elucidate the detailed mechanism behind this cooperative catalysis,we have conducted microsecond-scale MD simulations along the reaction *** simulations indicate that the substrate in the NC subunit induces W185 and Y141 adopting an open conformation in the C *** opening of W185(C)facilitates the entry of catalytic water,enhancing the catalytic activity for product formation,while the opening of Y141(C)creates an unfavorable environment for product binding,promoting its *** interaction network analysis reveals that the substrate in the NC subunit can induce conformational changes through a conserved water chain at the interface.

关键词： enzyme catalysis molecular dynamics cooperative effect pre-reaction state

Akkermansia muciniphila-directed polyphenol chlorogenic acid intervention for obesity in mice

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Food Science and Human Wellness 2024年第1期13卷 90-100页

作者： Xiaoxiang Gao chenbo yue Ruocen tian Leilei yu Fengwei tian Jianxin Zhao Wei chen Qixiao Zhai State Key Laboratory of Food Science and Technology Jiangnan UniversityWuxi 214122China School of Food Science and Technology Jiangnan UniversityWuxi 214122China National Engineering Research Center for Functional Food Jiangnan UniversityWuxi 214122China

Akkermansia muciniphila play an important in ameliorating obesity but is not allowed for direct consumption in most *** date,microbiota-directed foods selectively promote the targeted human gut microbes,providing a strategy for *** *** studies have indicated the potential regulation of the polyphenol on ***,a polyphenol screening based on *** upregulation was performed in *** acid(CGA)exhibited a greater response to *** ***,we found that CGA did not directly promote *** growth or mucin *** and metabolomics revealed that the increased abundance of *** resulted from the inhibition of CGA on Desulfovibrio and Alistipes and the influence of docosahexaenoic acid,β-hydroxybutyrate,and ***,to confirm the regulation of CGA on *** under disease conditions,high-fat diet-fed mice were *** results showed CGA promoted *** growth,and we expectedly found that CGA suppressed the augment in body weight of mice,significantly attenuated adipose tissue abnormality,provided liver protection and improved gut barrier *** results suggest that CGA inhibits the development of ***,our results indicate that microbiota-directed food is a promising approach for the treatment of obesity.

关键词： Akkermansia muciniphila polyphenol chlorogenic acid obesity