Study of the alkylation behaviors of antitumor agents to DNA using a quartz crystal resonator in PEG-DNA solution

 The alkylation of DNA by antitumor agents such as mechlorethamine hydrochloride (mustargen), thiophosphoramide (TSPA), mitomycin c (MMC), bleomycin-A₅ and dacarbazine (DTIC) can be detected with quartz crystal resonators (QCR). In the course of alkylation, the resonator frequency change in polyethylene glycol (PEG)-DNA solutions follows the cross-linking of DNA and the cleavage of the sugarphosphate backbone of DNA. It is at least partly attributed to the viscosity change of the PEG-DNA solution and possibly to some extent to the change of mass adsorbed on the QCR surface due to cross-linking and cleavage. Experimental results are consistent with that expected from theory. Received: 15 April 1996 / Revised: 3 July 1996 / Accepted: 9 July 1996     

溶剂聚合膜pH电极作内电极的气敏电极的研究

研究了以中性载体为活性物的石墨内导平头溶剂聚合膜(SPM)pH电极作内电极的二氧化碳和氨气敏电极。电极的性能取决于中性载体的特性,其中以菸酸十八酯为内电极膜活性物的二氧化碳气敏电极和以二辛基十八胺为活性物的氨气敏电极性能较佳。二氧化碳气敏电极用作丙酮酸脱羧酶酶电极的原电极,其性能院于传统的以玻璃pH电极作内电极的二氧化碳气敏电极。     

Multi-objective optimization of inverse planning for accurate radiotherapy

The multi-objective optimization of inverse planning based on the Pareto solution set, according to the multi-objective character of inverse planning in accurate radiotherapy, was studied in this paper. Firstly,the clinical requirements of a treatment plan were transformed into a multi-objective optimization problem with multiple constraints. Then, the fast and elitist multi-objective Non-dominated Sorting Genetic Algorithm (NSGA-Ⅱ)was introduced to optimize the problem. A clinical example was tested using this method. The results show that an obtained set of non-dominated solutions were uniformly distributed and the corresponding dose distribution of each solution not only approached the expected dose distribution, but also met the dosevolume constraints. It was indicated that the clinical requirements were better satisfied using the method and the planner could select the optimal treatment plan from the non-dominated solution set.     

Determination of structure parameters in strong-field ionization models of atoms

The Ammosov–Delone–Krainov (ADK) and Perelomov–Popov–Terent’ev (PPT) ionization models were widely used in strong-field physics and attosecond science due to their many attractive advantages such as simpler analytical formula, less computational demands, and satisfied accuracy of ionization rate. Based on the density-functional theory, we systematically determine accurate structure parameters of 25 atoms, 24 positive ions and 13 negative ions and tabulate for future applications. The wave function with correct asymptotic behavior is obtained by solving the time-independent Schrödinger equation with B-spline basis sets and the accurate structure parameters are extracted from this wave function in the asymptotic region. The accuracies of structure parameters are carefully examined by comparing the ionization probabilities (or yields) calculated by PPT and ADK models with those of solving the three-dimensional time-dependent Schrödinger equation and the experimental data.     

基于核酸适体的新型液晶生物传感用于检测血小板源性生长因子BB

利用核酸适体与其靶分子具有高度特异性结合的原理,建立了基于液晶取向改变的以核酸适体为捕获探针用于检测血小板源性生长因子BB(Platelet-derived growth factor BB,PDGF-BB)分子的新型液晶生物传感方法。核酸适体通过戊二醛偶联固定在3-氨丙基三乙氧基硅烷/N,N-二甲基-N-十八烷基[3-(三甲氧基硅基)丙基]氯化铵[(3-Aminopropyl)trimethoxysilane/N,N-dimethyl-N-octadecyl(3-aminopropyl)trimethoxysilyl chloride,APTES/DMOAP]混合自组装的传感基底表面,当靶分子PDGF-BB存在时,可与核酸适体发生特异性作用结合于传感基底表面,根据生物分子的空间尺寸效应能诱导液晶分子取向发生变化,从而引起光学信号的亮度和色彩发生改变,实现对PDGF-BB的快速检测。本方法具有操作简单、选择型好、灵敏度高的特点,在PDGF-BB浓度为5 nmol/L时仍可观察到明显的光学信号变化。     

Optimization of Single or Range of Harmonics by Using Two Gas Jets

The interference of high-order harmonics generated by two successive gas jets within a single laser pulse is discussed by a modeling with the inclusion of macroscopic propagation of the fundamental and harmonic fields in an ionizing medium. Based on the interference, we show that one can extract the laser Rayleigh range from the interference of harmonics and the accuracy of retrieve is independent of carrier-envelope phase while dependent on the pulse duration. Moreover~ we demonstrate that it is possible to optimize the single or range of harmonics with a high ratio relative to the adjacent orders by changing the separation of two gas jets, which is unavailable by using a single gas jet and linear polarized laser pulse.     

Single top production associated with a neutral scalar at LHC in topcolor-assisted technicolor

The topcolor-assisted technicolor(TC2)model predicts a number of neutral SCalars like the top-pion (π0t)and the top-Higgs(h0t).These scalar8 have flavor-changing neutral-current(FCNC)top quark couphngs,among which the top-charm transition couplings may be sizable.Such FCNC couplings induce single top productions associated with a neutral scalar at the CERN Large Hadron Collider(LHC)through the parton processes cg→tπ0t and cg→th0t.In this paper we examine these productions and find their production rates can exceed the 3σ sensitivity of the LHC in a large part of parameter space.Since in the Standard Model and the minimal supersymmetric model such rare productions have unobservably small production rates at the LHC.these rare processes will serve as a good probe for the TC2 model.     

Bs Semileptonic Decays to Ds and D^＊8 in Bethe-Salpeter Method

Using the relativistic Bethe-Salpeter method, the electron energy spectrum and the semileptonic decay widths of B^0 → Ds^- e＋ve and B^0 → Ds^＊-e＋ve are calculated. We obtain a large branching fraction Br（Bs → Dseve） = （2.85 ± 0.35）% and Br（Bs→ D^＊s eue） = （7.09 ±0.88）%, which can be easily detected in future experiments.     

含能配位聚合物[Co4(HBTI)4(H2O)8]的合成、结构、爆轰性能及催化性质

我们以4,5-双四唑咪唑（H₃BTI）为能量配体,利用水热法构筑了一例新型含能配合物[Co₄（HBTI）₄（H₂O）₈]（1）。晶体结构测定表明配合物1呈中心对称的四核结构,中心离子Co（Ⅱ）呈六配位的八面体几何构型。此外,结合Kissinger和Ozawa-Doyle两种方法对1进行非等温热动力学分析,并基于密度泛函理论计算出1的爆轰性能相关参数。配合物1的摩擦感度高于360 N,且撞击感度高于40 J。配合物1可同时催化高氯酸铵（AP）和1,3,5-三硝基-1,3,5-三嗪烷（RDX）的燃烧分解反应,其分解温度分别提前了25和11℃。