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Development and Application of Ultrafast Circular Dichroism Spectroscopy Techniques
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作者 Tong Cui Menghui Jia +5 位作者 Peicong Wu Ke Hu Xueli Wang Sanjun Zhang Haifeng Pan Jinquan Chen 《Chinese Journal of Chemical Physics》 SCIE EI CAS CSCD 2024年第4期449-460,I0093,共13页
Chirality hold broad applications in life sciences,quantum devices,and various other areas.Traditionally,molecular chirality can be characterized by using steady-state circular dichroism spectroscopy.However,the techn... Chirality hold broad applications in life sciences,quantum devices,and various other areas.Traditionally,molecular chirality can be characterized by using steady-state circular dichroism spectroscopy.However,the techniques that can characterize excited state chirality are progressively capturing the public interest as it can provide the dynamic information for chirality generation and transfer.In this review,we focus on the theoretical background and the developmental history of femtosecond time-resolved circular dichroism spectroscopy(TRCD)techniques around the world.Additionally,we provide examples to showcase the utility of these techniques in the analysis of the dynamical molecular chemical structures,the investigation of molecular chirality generation,and the detection of electron spin dynamics in semiconductor quantum dots. 展开更多
关键词 Excited state chirality Femtosecond time-resolved circular dichroism spectroscopy Ultrafast dynamics Chiral spectra
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Interactions Between Anticancer Pt(II) complexes and Human Erythrocyte Spectrin *
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作者 杨晓改 李荣昌 《Journal of Chinese Pharmaceutical Sciences》 CAS 1998年第3期9-14,共6页
The interactions between human erythrocyte spectrin(SP) and Pt(II) complexes with different composition and configuration were studied by fluorescence and circular dichroism spectra. The results showed that there are ... The interactions between human erythrocyte spectrin(SP) and Pt(II) complexes with different composition and configuration were studied by fluorescence and circular dichroism spectra. The results showed that there are 4.7×10 2 binding sites of cisplatin(CDDP) in a spectrin tetramer(SPT). Among them, about 70 sites with apparent binding constant K 1】3.47×10 6 were of highest affinity, 1.8×10 2 sites with K 2 = 3.47×10 6 were of high affinity, and other 2.2×10 2 sites with K 3 = 8.77×10 5 were of low affinity. The conformation change of spectrin, depending on the concentration of Pt(II) complex and molar ratio(R) of Pt(II) complex to spectrin, was induced by the binding of Pt(II) complexes. It indicated that the interaction of both CDDP and cis diaquodiamine platinum(DADP) with SP followed a two step first order kinetic process in the first stage (1 h), and the kinetic constants were determined. In the second stage, the induced conformation change, polymerization and depolymerization of SP were probably involved. It was noticed that in the reaction of SP and Pt(II) complexes with 1,2 cyclohexanediammine isomers as chiral carrier ligand, stereo matching played a more important role than the affinity of Pt(II) to thiol groups of SP. 展开更多
关键词 Pt (II) complex SPECTRIN CONFORMATION Binding sites Kinetic CHIRAL
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Scalar Susceptibility of QCD from Dyson-Schwinger Approach
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作者 WU Kong-Ping SHI Yuan-Mei +2 位作者 SUN Wei-Min PING Jia-Lun ZONG Hong-Shi 《Communications in Theoretical Physics》 SCIE CAS CSCD 2008年第1期189-192,共4页
In quantum chromodynamics (QCD), the scalar susceptibility represents the modification of the quark condensate, to a small perturbation of the parameter responsible for the explicit breaking of the symmetry, i.e., t... In quantum chromodynamics (QCD), the scalar susceptibility represents the modification of the quark condensate, to a small perturbation of the parameter responsible for the explicit breaking of the symmetry, i.e., the current quark mass. By studying the linear response of the dressed quark propagator to the presence of a nonzero quark mass, we derive a model-independent formula for the scalar susceptibility, which contains the dressed quark propagator G(p) and the dressed scalar vertex F(p, 0). The numerical values of the scalar susceptibility Xs are calculated within the framework of the rainbow-ladder approximation of the Dyson-Schwinger approach by employing two typical forms of model gluon propagator. 展开更多
关键词 scalar susceptibility explicit and dynamical chiral symmetry breaking Dyson-Schwinger equations
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A Highly Sensitive Femtosecond Time-Resolved Sum Frequency Generation Vibrational Spectroscopy System with Simultaneous Measurement of Multiple Polarization Combinations 被引量:2
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作者 谈军军 罗毅 叶树集 《Chinese Journal of Chemical Physics》 SCIE CAS CSCD 2017年第6期671-677,I0002,共8页
Characterization of real-time and ultrafast motions of the complex molecules at surface and interface is critical to understand how interracial molecules function. It requires to develop surface-sensitive, fast-identi... Characterization of real-time and ultrafast motions of the complex molecules at surface and interface is critical to understand how interracial molecules function. It requires to develop surface-sensitive, fast-identification, and time-resolved techniques. In this study, we employ several key technical procedures and successfully develop a highly sensitive femtosecond time-resolved sum frequency generation vibrational spectroscopy (SFG-VS) system. This system is able to measure the spectra with two polarization combinations (ssp and ppp, or psp and ssp) simultaneously. It takes less than several seconds to collect one spectrum. To the best of our knowledge, it is the fastest speed of collecting SFG spectra reported by now. Using the time-resolved measurement, ultrafast vibrational dynamics of the N-H mode of α-helical peptide at water interface is determined. It is found that the membrane environment does not affect the N-H vibrational relaxation dynamics. It is expected that the time-resolved SFG system will play a vital role in the deep understanding of the dynamics and interaction of the complex molecules at surface and interface. Our method may also provide an important technical proposal for the people who plan to develop time-resolved SFG systems with simultaneous measurement of multiple polarization combinations. 展开更多
关键词 Femtosecond time-resolved Sum frequency generation vibrational spectroscopy Ultrafast vibrational dynamics Multiple polarization combination measurement CHIRAL
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Comparing the effectiveness of karate and fitnes training on cognitive functioning in older adults——A randomized controlled trial
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作者 Kerstin Witte Siegfried Kropf +2 位作者 Sabine Darius Peter Emmermacher Irina B?ckelmann 《Journal of Sport and Health Science》 SCIE 2016年第4期484-490,共7页
Background:Recent studies demonstrate a slowdown in deterioration of cognitive functioning in old age through aerobic training.There is evidence that the combination of aerobic,balance,and coordination exercises lead... Background:Recent studies demonstrate a slowdown in deterioration of cognitive functioning in old age through aerobic training.There is evidence that the combination of aerobic,balance,and coordination exercises leads to an improvement or maintenance of cognitive functions.Such age-related exercises can especially be found in East Asian martial arts.The purpose of the current study is to verify whether karate training for older adults improves cognitive functioning and,if an improvement can be found,which cognitive field are influenced Methods:Eighty-nine older women and men(mean age:70 years) participated in this study.The participants were randomized into 2 intervention groups(karate group and fitnes group,duration of intervention:5 months) and a control group.All participants had to accomplish a cognitive test battery before and after the intervention.In a secondary study the karate group had an additional intervention for another 5 months.Results:The results show that there is a significan improvement in motor reactivity,stress tolerance,and divided attention only after the 5-month karate training period.Additionally,the results of the secondary study indicate further improvements after 10 months.Conclusion:The 5-month karate training can help to enhance attention,resilience,and motor reaction time,but a training period of 10 months is even more efficient 展开更多
关键词 COGNITION Divided attention KARATE Motor reactivity Older adults Physical exercise
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Quark Condensate in the Strange Matter
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作者 LU-Chang-Fang LUXiao-LU 《Communications in Theoretical Physics》 SCIE CAS CSCD 2003年第5期593-596,共4页
In a nonlinear chiral SU(3) framework, we investigate the quark condensate in the strange matter including and Λ, making use of chiral symmetry spontaneous breaking Lagrangian and mean-field approximation. The resul... In a nonlinear chiral SU(3) framework, we investigate the quark condensate in the strange matter including and Λ, making use of chiral symmetry spontaneous breaking Lagrangian and mean-field approximation. The results show that the chiral symmetry is restored partially when the strange matter density increases and that plays a very important role in the strange matter which may approach the constituents of the neutron stars. In addition, we can find that the strange matter density where the π-condensate emerges leads to the ratio of the nucleon number to baryon number. 展开更多
关键词 quark condensate chiral symmetry spontaneous breaking Lagrangian Hellmann-Feynman theory
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Mixed Quark-Gluon Condensate Beyond Chiral Limit
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作者 卢常芳 吕晓夫 《Communications in Theoretical Physics》 SCIE CAS CSCD 2010年第5期893-897,共5页
Using the Dyson-Schwinger equation and perturbation theory, we calculate the mixed quark-gluon condensates in the chiral limit and in the case of nonzero quark current mass for the light quark u/d and strange quark s.... Using the Dyson-Schwinger equation and perturbation theory, we calculate the mixed quark-gluon condensates in the chiral limit and in the case of nonzero quark current mass for the light quark u/d and strange quark s. The results show that the mixed quark-gluon condensate will decrease when the quark mass increases. For the quark with zero mass, we obtain mo2 = g(qσuvGuvq)/(qq) 0.68 GeV2, which is in good agreement with the QCD sum rules estimate mo2=(0.8± 0.2) GeV2. 展开更多
关键词 quark current mass mixed quark-gluon condensates QCD sum rule Schwinger Dyson equation Feynman rules
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Influence of Chiral Mean Field on Kaon In-plane Flow in Heavy Ion Collisions
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作者 ZHENGYu-Ming FUCHSChristian +4 位作者 FAESSLERAmand SHEKHTERKirril SRISAWADPornrad KOBDAJChinorat YANYu-Peng 《Communications in Theoretical Physics》 SCIE CAS CSCD 2004年第5期746-750,共5页
The influence of the chiral mean field on the in-plane flow in heavy ion collisions at SIS energy is investigated within covariant kaon dynamics. For the kaon mesons inside the nuclear medium a quasi-particle picture... The influence of the chiral mean field on the in-plane flow in heavy ion collisions at SIS energy is investigated within covariant kaon dynamics. For the kaon mesons inside the nuclear medium a quasi-particle picture including scalar and vector fields is adopted and compared to the standard treatment with a static potential. It is confirmed that a Lorentz force from spatial component of the vector field provides an important contribution to the in-medium kaon dynamics and strongly counterbalances the influence of the vector potential on the in-plane flow. The calculated results show that the new FOPI data can be reasonably described using the Brown & Rho parametrization, which partly takes into account the correction of higher order contributions in the chiral expansion. This indicates that one can abstract the information on the kaon potential in a nuclear medium from the analysis of the in-plane flow. 展开更多
关键词 kaon in-plane flow kaon mean field covariant kaon dynamics heavy ion collision
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大鼠体内肌肽的手性药动学
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作者 苏丹 宋永贵 +4 位作者 魏斌斌 耿璐璐 杨世林 毕开顺 陈晓辉 《中国医院药学杂志》 CAS CSCD 北大核心 2011年第22期1874-1877,共4页
目的:应用柱前衍生结合高效液相-荧光检测法对大鼠体内的肌肽手性转化和代谢动力学进行研究,进而探讨体内肌肽酶的作用特点。方法:采用邻苯二甲醛和N-乙酰-L-半胱氨酸为柱前手性衍生化试剂,检测大鼠血浆中L型肌肽(L-carnosine)和D型肌肽... 目的:应用柱前衍生结合高效液相-荧光检测法对大鼠体内的肌肽手性转化和代谢动力学进行研究,进而探讨体内肌肽酶的作用特点。方法:采用邻苯二甲醛和N-乙酰-L-半胱氨酸为柱前手性衍生化试剂,检测大鼠血浆中L型肌肽(L-carnosine)和D型肌肽(D-carnosine)的浓度,应用非房室模型对所获得的血药浓度-时间数据进行拟合,计算药动学参数。结果:L-CAR和D-CAR在大鼠体内代谢具有明显的立体选择性,AUC0-∞分别为(5 641±448)ng.h.mL-1和(6 160±277)ng.h.mL-1(P<0.05),tmax分别为(0.75±0.02)h和(2.50±0.38)h(P<0.05),Cmax分别为(5 396±258)ng.mL-1和(1 958±192)ng.mL-1(P<0.05),CL/F分别为(13.36±1.02)L.h-1.kg-1和(12.19±0.56)L.h-1.kg-1(P<0.05)。并且D-CAR和L-CAR均未进行单向转化。结论:L-CAR和D-CAR在大鼠体内的药动学有明显的立体选择性(其差异主要应是肌肽酶对L-CAR作用的高度光学选择性)。肌肽对映体并未在氨基酸消旋酶作用下发生手性转化。 展开更多
关键词 L型肌肽 D型肌肽 手性动力 肌肽酶 手性转化
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Changes in cerebral hemodynamics in patients with posttraumatic diffuse brain swelling after external intraventricular drainage 被引量:13
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作者 Kefei Chen Jirong Dong +4 位作者 Tian Xia Chunlei Zhang Wei Zhao Qinyi Xu Xuejian Cai 《Chinese Journal of Traumatology》 CAS CSCD 2015年第2期90-94,共5页
Purpose: To investigate the changes of cerebral hemodynamics pre- and post-ventricular drainage in patients with posttraumatic acute diffuse brain swelling. Methods: Twenty-four cases of traumatic diffuse brain swel... Purpose: To investigate the changes of cerebral hemodynamics pre- and post-ventricular drainage in patients with posttraumatic acute diffuse brain swelling. Methods: Twenty-four cases of traumatic diffuse brain swelling were analyzed retrospectively. Patients in nonsurgical group were treated by medicine therapy. Patients in surgical group were treated by external ventricular drainage plus medicine therapy. The first CT perfusion scan was completed within 4 -5 h after trauma and scanned again after 7 days. The changes of perfusion parameters in area-of- interest in two groups were analyzed and compared before and after treatment. Results: Compared with the nonsurgical group, the value of cerebral blood volume, cerebral blood flow and mean transit time in bilateral frontal temporoparietal grey matter, basal ganglia, cerebellum, and brain stem at pre- and post-therapy were increased significantly (p 〈 0.05) in surgical group, and consequently the prognosis of patients undergoing surgery was also better than that of nonsurgical group. Conclusion: External ventricular drainage can improve cerebral perfusion and increase survival quality for the patients with posttraumatic acute diffuse brain swelling. 展开更多
关键词 Brain injuries Brain edema Perfusion imaging Hemodynamics
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Design of Off-statistics Axial-flow Fans by Means of Vortex Law Optimization
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作者 Andrea Lazari Andrea Cattanei 《Journal of Thermal Science》 SCIE EI CAS CSCD 2014年第6期505-515,共11页
Off-statistics input data sets are common in axial-flow fans design and may easily result in some violation of the requirements of a good aerodynamic blade design.In order to circumvent this problem,in the present pap... Off-statistics input data sets are common in axial-flow fans design and may easily result in some violation of the requirements of a good aerodynamic blade design.In order to circumvent this problem,in the present paper,a solution to the radial equilibrium equation is found which minimizes the outlet kinetic energy and fulfills the aerodynamic constraints,thus ensuring that the resulting blade has acceptable aerodynamic performance.The presented method is based on the optimization of a three-parameters vortex law and of the meridional channel size.The aerodynamic quantities to be employed as constraints are individuated and their suitable ranges of variation are proposed.The method is validated by means of a design with critical input data values and CFD analysis.Then,by means of systematic computations with different input data sets,some correlations and charts are obtained which are analogous to classic correlations based on statistical investigations on existing machines.Such new correlations help size a fan of given characteristics as well as study the feasibility of a given design. 展开更多
关键词 axial flow fan statistical correlations optimum design feasibility study
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