Design,synthesis and in vivo anti-hyperglycemic activity of gem-dimethyl-bearing C-glucosides as SGLT2 inhibitors

A series of gem-dimethyl-bearing C-glucosides were designed and synthesized as SGLT2 inhibitors,with anhydrous aluminum chloride-mediated Friedel-Crafts alkylation to construct the gem-dimethyl functionality being the key step.The in vivo anti-hyperglycemic activity was evaluated with mice oral glucose tolerance test(OGTT),and all the synthesized compounds showed significant but less potent anti-hyperglycemic activity than the positive control dapagliflozin.     

Three New Compounds from Securidaca inappendiculata

Three new compounds, 2‐methoxy‐3,4‐(methylenedioxy)benzophenone ( 1 ), 4‐hydroxy‐2,3‐dimethoxybenzophenone ( 2 ), and 3‐hydroxy‐4,6‐dimethoxy‐9H‐xanthen‐9‐one ( 3 ), besides three known compounds were isolated from the roots of Securidaca inappendiculata. Their structures were established by spectroscopic means and X‐ray crystallographic diffraction analysis. The biogenetic relationships among these six compounds are discussed.     

Investigation on activating individual living monocytic U937 cell by interleukin-6 using Raman tweezers

We investigate the activation of living monocytic U937 cells induced by interleukin-6 （IL-6） at the single cell level. We employ home-built Raman tweezers to measure the Raman spectra of living U937 cells with and without IL-6 at the single cell level. Raman peaks of amide III, amide I, DNA backbone, as well as guanine and adenine in U937 cells, change at 1312, 1652, 1090, and 1576 cm ？1 , respectively, shortly after IL-6 is added in the medium. The change is a dynamic temporal process. In the activation process of U937 cells induced by IL-6, the protein signals recover in 20 min, while the nucleic acid signals continue to increase for 20 min. The results reveal that the biochemical cascades of activation in signal transduction induced by IL-6 can be investigated in situ at the single cell level.     

Performance of gain-switched all-solid-state quasi-continuous-wave tunable Ti:sapphire laser system

We have made a gain-switched all-solid-state quasi-continuous-wave （QCW） tunable Ti：sapphire laser system, which is pumped by a 532 nm intracavity frequency-doubled Nd：YAG laser. Based on the theory of gain-switching and the study on the influencing factors of the output pulse width, an effective method for obtaining high power and narrow pulse width output is proposed. Through deliberately designing the pump source and the resonator of the Ti：sapphire laser, when the repetition rate is 6 kHz and the length of the cavity is 220 mm, at an incident pump power of 22 W, the tunable Ti：sapphire laser from 700 to 950nm can be achieved. It has a maximum average output power of 5.6W at 800nm and the pulse width of 13.2 ns, giving an optical conversion efficiency of 25.5% from the 532 mn pump laser to the Ti：sapphire laser.     

飞秒脉冲振幅和相位的无干涉条纹重构法测量

对作者所提出的无干涉条纹直接电场重构测量飞秒脉冲的振幅和相位的新方法作出进一步理论分析，并通过实验测量说明该方法的优越性.该方法克服了传统的SPIDER方法的弊病，能得到一组无干涉条纹的图像，排除传统方法必须使用傅里叶变换滤波消除干涉条纹而引进的系统误差，使得该方法能够采用较简便设备且能较准确测量飞秒脉冲强度轮廓和相位.最后给出同一条件下新方法和传统SPIDER方法分别重构的脉冲强度自相关曲线与实验测量结果的比较，以说明新方法的有效性和优越性.     

Revisiting the security of quantum dialogue and bidirectional quantum secure direct communication

From the perspective of information theory and cryptography, the security of two quantum dialogue protocols and a bidirectional quantum secure direct communication (QSDC) protocol was analyzed, and it was pointed out that the transmitted information would be partly leaked out in them. That is, any eavesdropper can elicit some information about the secrets from the public annunciations of the legal users. This phenomenon should have been strictly forbidden in a quantum secure communication. In fact, this problem exists in quite a few recent proposals and, therefore, it deserves more research attention in the following related study. Supported by the National High Technology Research and Development Program of China (Grant No. 2006AA01Z419), the National Natural Science Foundation of China (Grant Nos. 90604023 and 60373059), the National Research Foundation for the Doctoral Program of Higher Education of China (Grant No. 20040013007), the National Laboratory for Modern Communications Science Foundation of China (Grant No. 9140C1101010601), the Natural Science Foundation of Beijing (Grant No. 4072020) and the ISN Open Foundation     

Exact Rates of Convergence of Functional Limit Theorems for Csörgő;-Révész Increments of a Wiener Process

Let {W(t); t≥ 0} be a standard Wiener process and S be the Strassen set of functions. We investigate the exact rates of convergence to zero (as T→∞) of the variables $ \sup _{{0 \leqslant t \leqslant T - \alpha _{T} }} \inf _{{f \in S}} \sup _{{0 \leqslant x \leqslant 1}} {\left| {Y_{{t,T}} {\left( x \right)} - f{\left( x \right)}} \right|} Let {W(t); t≥ 0} be a standard Wiener process and S be the Strassen set of functions. We investigate the exact rates of convergence to zero (as T→∞) of the variables sup_{0≤ t ≤ T − aT} inf _f∈S sup_{0≤ x ≤1}|Y _t,T (x) −f(x)| and inf_{0≤ t ≤ T−aT} sup_{0≤ x ≤1}|Y _t,T (x−f(x)| for any given f∈S, where Y _t,T (x) = (W(t+xa _T ) −W(t)) (2a _T (log Ta _T ⁻¹ + log log T))^−1/2. We establish a relation between how small the increments are and the functional limit results of Cs?rg{\H o}-Révész increments for a Wiener process. Similar results for partial sums of i.i.d. random variables are also given. Received September 10, 1999, Accepted June 1, 2000     

在实验室建设中深化近代物理实验教学体系改革

介绍了南开大学物理科学学院近代物理实验室通过“基地”、“211工程”和“世行贷款”等实验室建设,对近代物理实验教学体系进行改革的概况。     

On creation of Hopf bifurcations in discrete-time nonlinear systems

Bifurcation characteristics of a nonlinear system can be manipulated by small controls. In this paper, we present a control method to create Hopf bifurcations in discrete-time nonlinear systems. The critical conditions for the Hopf bifurcations are discussed. The center manifold method, normal form technique and the Iooss's Hopf bifurcation theory are employed in the derivation of the control gain. Numerical demonstration is provided. (c) 2002 American Institute of Physics.