Cytotoxicity of Postmodified Zeolitic Imidazolate Framework‐90 (ZIF‐90) Nanocrystals: Correlation between Functionality and Toxicity

Using a simple method, the aldehyde groups of zeolitic imidazolate framework‐90 (ZIF‐90) nanocrystals were converted into carboxyl, amino, and thiol groups, without affecting the integrity of the framework. Notably, for the first time, correlations between functionality and cytotoxicity are also demonstrated via in vitro cytotoxicity assays. The positive charged aminated‐ZIF‐90 presumably results in either perturbation of cell membrane, more efficient cell uptake, or both. Therefore, the half‐maximal effective (EC₅₀) concentration of aminated‐ZIF‐90 has a higher cytotoxicity of about 30 μg mL^?1.     

Steric effects ih the reaction of di(bromomagnesio)alkanes with carboxylic esters

Largely different product distributions were observed on the action of various carboxylic esters with 1,4-di(bromomagnesio)butane and its homologue 1,5-di(bromomagnesio)pentane. The much larger yields of reduction product with the latter are the evidence for the structural geometric requirements for the annelation step.     

Comparison of 13C- and 1H-Magnetic Resonance Spectroscopy as Techniques for the Quantitative Investigation of Dynamic Processes. The cope rearrangement in bullvalene

The potential advantages of ¹³C-(¹H-noise decoupled) spectroscopy (in the Fourier transform mode) over ¹H-spectroscopy for the quantitative investigation of molecular dynamic process is discussed. The Cope rearrangement in bullvalene, an example of complex exchange of spins over different magnetic sites, has been studied by both kinds of spectroscopy as a test.     

具有双稳性的化学反应中的慢化现象

从理论分析和计算模拟两方面对具有双稳性的化学反应中的慢化现象进行了研究．指出两类临界点附近的慢化现象（即所谓的临界慢化），并且计算出了它们随时间的慢化指数．进一步讨论了另一种与不稳工作点有关的远离临界点的慢化现象，讨论具有一定的普适性．     

A General Approach to the Physician Rostering Problem

This paper presents a hybridization of a Constraint Programming (CP) model and search techniques with Local Search (LS) and some ideas borrowed from Genetic Algorithms (GA). The context is the physician rostering problem, whose instances can vary greatly and for which almost no general tool has been developed. It is hoped that the combination of the three techniques will lead to an algorithm that has sufficient flexibility to solve most instances with a small amount of customization. To achieve this goal we also introduce Generic constraints: these constraints are used to model several types of ergonomic constraints that are found amongst physician rostering problems.     

D-glycopyranosyl phenylsulfones: Their use in a stereocontrolledsynthesis of cis-2,6-disubstituted tetrahydropyrans (β-d-c-clycosides)

The lithiated anion derived from 3,4,6-tri-O-t-butyldimethylsilyl-2-deoxy-α, β-D-gluco-pyranosyl phenylsulfones 1 reacts with various electrophiles leading to alkylated products, precursors of β-D-C-glycosides 5–g after stereocontrolled desulfonylation and hydrolysis.     

Synthesis of 1-(2′-O-methyl-β-d-ribofuranosyl)-5-nitroindole and its phosphoramidite derivative

The synthesis of 1-(2′-O-methyl-β-d-ribofuranosyl)-5-nitroindole, a new nucleoside containing the universal base 5-nitroindole, and its phosphoramidite derivative for incorporation into oligonucleotides is described.     

Shape optimization by the homogenization method

Summary. In the context of shape optimization, we seek minimizers of the sum of the elastic compliance and of the weight of a solid structure under specified loading. This problem is known not to be well-posed, and a relaxed formulation is introduced. Its effect is to allow for microperforated composites as admissible designs. In a two-dimensional setting the relaxed formulation was obtained in [6] with the help of the theory of homogenization and optimal bounds for composite materials. We generalize the result to the three dimensional case. Our contribution is twofold; first, we prove a relaxation theorem, valid in any dimensions; secondly, we introduce a new numerical algorithm for computing optimal designs, complemented with a penalization technique which permits to remove composite designs in the final shape. Since it places no assumption on the number of holes cut within the domain, it can be seen as a topology optimization algorithm. Numerical results are presented for various two and three dimensional problems. Received July 4, 1995