Mathematical optimization in intensity modulated radiation therapy

The design of an intensity modulated radiotherapy treatment includes the selection of beam angles (geometry problem), the computation of an intensity map for each selected beam angle (intensity problem), and finding a sequence of configurations of a multileaf collimator to deliver the treatment (realization problem). Until the end of the last century research on radiotherapy treatment design has been published almost exclusively in the medical physics literature. However, since then, the attention of researchers in mathematical optimization has been drawn to the area and important progress has been made. In this paper we survey the use of optimization models, methods, and theories in intensity modulated radiotherapy treatment design.     

双桥联环糊精二聚体的合成与应用

双桥联环糊精二聚体是一种新型的超分子体系,具有许多独特的性能和潜在的应用前景.综述了双桥联环糊精二聚体的合成方法以及其在模拟生物酶、模拟生物蛋白、模拟细胞膜、构建新型功能材料等领域中的应用.     

Crystal growth and spectral properties of Nd3+:Ca9Gd(VO4)7 crystal

An Nd³⁺:Ca₉Gd(VO₄)₇ crystal with dimensions of ?25×30 mm³ was grown by the Czochralski method. The hardness, thermal expansion coefficient and thermal conductivity coefficient of the crystal were measured. The spectroscopic characteristics of Nd³⁺:Ca₉Gd(VO₄)₇ crystals were investigated. The absorption band at 810 nm has an FWHM of 10 nm, and absorption cross-sections are 5.81×10^?20 cm² for π-polarization and 7.47×10^?20 cm² for σ-polarization at 810 nm. The emission cross-sections at 1067 nm are 4.2×10^?20 and 6.5×10^?20 cm² for π- and σ-polarizations, respectively. The quantum efficiency η_c is equal to 94.3%. To sum up the above results, Nd³⁺:Ca₉Gd(VO₄)₇ crystal can be regarded as a highly efficient solid state laser material.     

大孔吸附树脂富集板蓝根中(R,S)-告依春工艺研究

采用静态吸附法考察了D101、AB-8、NKA-2、NKA-9、HPD 100、HPD600等6种大孔吸附树脂对(R,S)-告依春的吸附及解吸性能,筛选出效果最佳的AB-8树脂,并对其进行动态考察.最佳富集条件为:上样液pH 6,生药质量-体积浓度为0.200g/mL,解吸液为2BV量70％乙醇,在优化条件下(R,S)-告依春在浸膏中含量可从0.76％提高到12.48％.结果表明,AB-8型大孔吸附树脂可用来从板蓝根水提取液中富集(R,S)-告依春.     

中国科学院近代物理研究所磁体工程进展概述(英文)

本文着重论述了中国科学院近代物理研究所目前正在研制的三大磁体工程,它们包括重离子治癌工程(HIMM),强流重离子加速器(HIAF)工程,以及加速器驱动次临界系统(ADS)。在HIMM工程中的常规磁体建设中,着重介绍了联合运用钝化槽与活极头两项技术改善磁场品质的设计方法,并且运用Opera-3D设计软件,对该类高场常规磁体进行了数值分析,进一步地测量了该磁体磁场分布情况,相关的测量结果与数值模拟结果吻合良好。而对于正在处于预研阶段的HIAF工程中的快脉冲超导二极磁体,讨论了超导磁体的前期设计与结构优化技术,包括CACC超导线缆的结构设计,80 K冷屏与线圈盒结构的优化,力-磁耦合结构计算方法等。而在嬗变核废料处理的C-ADS注入器II中,核心部件是具有高磁场(高达7～8 T)的多层复合超导螺线管磁体结构,介绍了其在励磁和失超过程中相关磁学和力学多场实验测试工作。这些相关的设计和测量技术将为中国科学院近代物理研究所自主研制的磁体工程的物理和结构设计提供方法和指导。     

Magnetic relaxation behavior of lanthanide substituted Dawson-type tungstoarsenates

Two new polyoxometalate compounds [(CH₃)₄N]₈[Ln(H₂O)₈]₂[(α₂-As₂W₁₇O₆₁)Ln(H₂O)₂]₂·nH₂O (Ln=Er (1), Dy (2)) have been prepared by the trivacant Dawson-type anion [α-As₂W₁₅O₅₆]¹²⁻ and trivalent rare earth ion and characterized by single-crystal X-ray diffraction, IR spectra, thermogravimetric and electrochemical analyses. The centrosymmetric polyoxoanion, {[(α₂-As₂W₁₇O₆₁)Ln(H₂O)₂]₂}¹⁴⁻, bounded to each other via Ln³⁺ connecting to terminal W-O oxygen atoms. Furthermore, the polyoxoanions are linked by [Ln(H₂O)₈]³⁺ to form an extensive 3D supramolecular network structure depending on hydrogen bond. The magnetic properties of the two compounds have been studied by measuring their magnetic susceptibilities in the temperature range 2.0-300.0 K, indicating the depopulation of the stark components at low temperature and/or very weak antiferromagnetic interactions between magnetic centers. Low-temperature ac magnetic susceptibility measurements reveal a slow magnetic relaxation behavior for 2.     

Vesicles prepared by β-cyclodextrins Inclusion complexes based on switching supramolecular interaction models induced by mixed solvents

Vesicles, based on two-head inclusion model (2:1) and one-head inclusion model (1:1) of carboxymethyl-β-cyclodextrin (CM-β-CD) with N,N′-bis (ferrocenylmethylene) diaminohexane (BFD) were prepared in water as well as in mixed solvents (water/methanol, water/ethanol, water/isopropanol, water/tert-butanol and water/glycerol). Morphologies and sizes of the aggregates in water and mixed solvents were observed by TEM and confirmed by DLS. A gradual change was shown with increasing proportion of the organic component in the mixed solvents. The polarities and steric hindrances of the mixed solvents would play key roles in the morphological changes of aggregates. Moreover, two possible formation mechanisms in different solvents were proposed based on UV, CV and ¹H-NMR data. The work in this paper may extend the applications of vesicles in biosimulation, drug-delivery and smart materials.     

In vivo characterization of 99mTc-spermine in mice bearing human breast cancer xenografts

The usability of ^99mTc-spermine for human breast tumor imaging was evaluated. Mice bearing MDA-MB-231 breast tumor were used for SPECT imaging and biodistribution study. Tumor was imaged clearly after injection with ^99mTc-spermine. The accumulation of ^99mTc-spermine was much lower in chest region than that of general breast tumor imaging agent ^99mTc-MIBI. It suggests that ^99mTc-spermine is promising for breast cancer imaging.     

Synthesis and Characterization of Some New Star-Shaped Polydentate Ligands from 2,4,6-Trichloro-1,3,5-triazine

Some new star-shaped polydentate ligands were synthesized using 2,4,6-tris(p-formylphenoxy)-1,3,5-triazine as a template and were characterized by infrared, ¹H NMR, and ¹³C NMR spectra and elemental analysis. These products may form polynuclear complexes with metal ions, and the complexes may possess potential applications in the area of electromaterials, optomaterials, magnetic materials, and bio-organic materials.