A remark on H1 mappings

With , we here construct, for each positive integer N, a smooth function of degree zero so that there must be at least N singular points for any map that minimizes the energy in the family . The infimum of over U(g) is strictly smaller than the infimum of over the continuous functions in U(g). There are some generalizations to higher dimensions.Research partially supported by the National Science FoundationResearch supported by an Alfred P. Sloan Graduate Fellowship     

Theoretical and Experimental Studies on a Metallorganic Complex of (Isopropylxanthato)(Phenyl)Mercury(I) [Hg(I)(C<Subscript>6</Subscript>H<Subscript>5</Subscript>)(C<Subscript>4</Subscript>H<Subscript>7</Subscript>OS<Subscript>2</Subscript>)]

The title compound, (isopropylxanthato)(phenyl)mercury(I), was synthesized and characterized by elemental analysis, IR and thermogravimetric analysis. Density functional theory (DFT) method calculations were performed at B3LYP/CEP-121G and B3LYP/CEP-31G levels of theory, respectively. Vibrational frequencies were predicted, assigned, compared with the experimental values, and they are supported each other. The calculated results show that the strength of bond Hg—C is stronger than that of Hg—S, which is good agreement with the experimental data. The calculations of the second order optical nonlinearity and electronic absorption spectra are also performed.     

三碳菁染料的研究

三碳菁染料的吸收在近红外区,可用作卤化银感光材料的红外增感染料,近年来在红外激光染料和光信息记录介质等方面也得到了开发及应用。在多甲川链上引入桥环可提高染料的稳定性。本文合成了9种含芳胺基取代的桥链三碳菁,讨论染料结构与其增感性能关系。     

分光光度计与计算机联机

人工记录的方法进无法准确记录分光光度计所批示的消光值，特别是因浓度（１０＾－５－１０＾－４ｍｏｌ／Ｌ）改变，而导致精度和准确度不高，采用计算机的方式是可以克服此种弊端，精确度和准确度都很高并有良好线性关系，且自动绘图（即经耳定律的线性图）并输出。此装置具有快速、直观、图文并茂等特点。     

Concise Synthesis and Antimicrobial Activities of New Substituted 5‐Isoxazolpenicillins

The synthesis of a series of new 5‐isoxazolpenicillins is described, which were obtained by coupling substituted isoxazoles with 6‐APA. Concise large‐scale synthesis of 3,5‐disubstituted isoxazoles by 1,3‐dipolar cycloaddition using copper(I) as catalyst was also investigated. Representative compounds were assayed for antimicrobial activities, showing satisfactory antimicrobial activities against Gram‐negative bacteria.     

微波辐射下4-(4-羟基-3-甲氧基)苯基-3,3,6,6-四甲基-1,8-二氧代1,2,3,4,5,6,7,8,9,10-十氢吖啶的合成和晶体结构

标题化合物C24H29NO4?1/2C2H5OH稨2O)由香兰素、5,5-二甲基-1,3-环己二酮、醋酸铵在微波辐射下干反应并经95%乙醇重结晶而得C24H29NO4穀2(C2H5OH稨2O)晶体。结构通过单晶X-射线衍射法确定,其晶体属单斜晶系,空间群P21/n, a = 9.810(2), b = 14.516(3), c = 17.008(3) ? b = 101.03(2), V = 2377.2(8) ?, Z = 4, Mr = 427.52, Dc = 1.195 g/cm3 , m(MoKa) = 0.082 mm-1, F(000) = 920。晶体结构用直接法解出,经全矩阵最小二乘法对原子参数进行修正,最终的偏离因子为R = 0.0406, wR = 0.0892。X-射线衍射分析结果表明,吡啶环和与之稠合的2个六员环均为信封式构象。     

Liquid Chromatographic Analysis of Arabinosylcytosin and 1-β-D-Arabinofuranosyluracil in Treatment with Cyclophosphamide and Pirarubicin

A reversed-phase liquid chromatographic (RPLC) method has been developed for determination of arabinosylcytosin (Ara-C) and its metabolite 1-β-D-arabinofuranosyluracil (Ara-U) on a 250 mm × 4.6 mm i.d., 5 μm particle, Diamonsil C₁₈ column. The mobile phase was a mixture of 5% methanol and 95% 10 mmol L⁻¹ phosphate buffer adjusted to pH 5.5. The flow-rate was 1.0 mL min⁻¹ and the injection volume 20 μL. Eluting compounds were detected at 270 nm by use of an ultraviolet detector. Under these LC conditions cyclophosphamide (CTX) and pirarubicin (THP), two other medicines given with Ara-C in clinical treatment, do not interfere with measurement of Ara-C and Ara-U. Individual calibration plots of peak area against concentration generated from analysis of standard solutions were used to calculate the concentrations of Ara-C and Ara-U in sample solutions. The calibration plot was linear in the range 2.5–100 μg mL⁻¹, the average recovery of Ara-C and Ara-U was more than 98% (RSD < 2.5%), and between-day and within-day precision, expressed as relative standard deviation (RSD), were below 4.0%. LOQ for both Ara-C and Ara-U was 2 μg mL⁻¹. The method is rapid, simple, accurate and reproducible, and especially useful for application to patient samples.     

A synthesis of aromatic five- and six-membered B-N heterocycles via ring closing metathesis

The ring closing metathesis on appropriate vinyl or allyl aminoboranes (1 or 2) gives azaboracycloalkenes (3 or 4) which can be converted to azaborolides (5) or azaborines (6).     

Highly efficient visible-light photocatalytic ethane oxidation into ethyl hydroperoxide as a radical reservoir

Photocatalytic ethane conversion into value-added chemicals is a great challenge especially under visible light irradiation. The production of ethyl hydroperoxide (CH₃CH₂OOH), which is a promising radical reservoir for regulating the oxidative stress in cells, is even more challenging due to its facile decomposition. Here, we demonstrated a design of a highly efficient visible-light-responsive photocatalyst, Au/WO₃, for ethane oxidation into CH₃CH₂OOH, achieving an impressive yield of 1887 μmol g_cat⁻¹ in two hours under visible light irradiation at room temperature for the first time. Furthermore, thermal energy was introduced into the photocatalytic system to increase the driving force for ethane oxidation, enhancing CH₃CH₂OOH production by six times to 11 233 μmol g_cat⁻¹ at 100 °C and achieving a significant apparent quantum efficiency of 17.9% at 450 nm. In addition, trapping active species and isotope-labeling reactants revealed the reaction pathway. These findings pave the way for scalable ethane conversion into CH₃CH₂OOH as a potential anticancer drug.

Highly efficient visible-light driven photocatalytic oxidation of ethane into ethyl hydroperoxide was realized for the first time over Au/WO₃.     

Amperometric Glucose Biosensor Based on Platinum Nanoparticles Combined Aligned Carbon Nanotubes Electrode

A sensitive amperometric glucose biosensor based on platinum nanoparticles (PtNPs) combined aligned carbon nanotubes (ACNTs) electrode was investigated. PtNPs which can enhance the electrocatalytic activity of the electrode for electrooxidating hydrogen peroxide by enzymatic reaction were electrocrystallized on 4‐aminobenzene monolayer‐grafted ACNTs electrode by potential‐step method. These PtNPs combined ACNTs' (PtNPs/ACNTs) surfaces were characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The highly dispersed PtNPs on ACNTs can be obtained. The enzyme electrode exhibits excellent response performance to glucose with linear range from 1×10^?5–7×10^?3 mol L^?1 and fast response time within 5 s. Furthermore, this glucose biosensor also has good reproducibility. It is demonstrated that the PtNPs/ACNTs electrode with high electrocatalytic activity is a suitable basic electrode for preparing enzyme electrodes.