A Synthesis of Two 1,4-Dihydropyridine Derivatives Labeled with Carbon-14 Using Conventional Heating,Microwave Irradiation,and Solid-State Reaction

Radiochemistry - Three modes of the reaction for labeling of dihydropyridine compounds were studied: thermal heating, microwave irradiation, and solid-state process.     

A generic biokinetic model for Carbon-14

The generic biokinetic model currently recommended by the International Commission on Radiological Protection (ICRP) for the treatment of systemic radiocarbon assumes uniform distribution of activity in tissues and a biological half-time of 40 d. This model is intended to generate cautiously high estimates of dose per unit intake of C-14 and, in fact, generally predicts a much higher effective dose than systemic models that have been developed on the basis of biokinetic studies of specific carbon compounds. The simplistic model formulation precludes its application as a bioassay model or adjustment to fit case-specific bioassay data. This paper proposes a new generic biokinetic model for systemic radiocarbon that is less conservative than the current ICRP model but maintains sufficient conservatism to overestimate the effective dose coefficients generated by most radiocarbon-compound-specific models. The proposed model includes two systemic pools with different biological half-times representing an initial systemic form of absorbed radiocarbon, a submodel describing the behaviour of labelled carbon dioxide produced in vivo, and three excretion pathways: breath, urine and faeces. Generic excretion rates along each path are based on multi-phase excretion curves observed in experimental studies of radiocarbons. The generic model structure is designed so that the user may adjust the level of dosimetric conservatism to fit the information at hand and may adjust parameter values for consistency with subject-specific or site-specific bioassay data.     

Synthesis of Labeled Compounds Using Labeled Reagents

Methods are considered for tritium labeling by reduction of appropriate precursors with complex metal tritides, condensation of appropriate precursors with labeled reagents, and chemical synthesis.     

14CrODS铁素体钢的制备及其拉伸性能

通过机械合金化制备了成分(质量分数/%)为Fe-14Cr-0.5Ti-0.35Y2O3的氧化物弥散强化合金粉末,机械合金化后粉末内部各合金元素分布均匀。采用热等静压的方法制得14CrODS铁素体钢,并对其进行锻造和热处理。与未添加氧化物弥散颗粒的14CrNA相比,14CrODS钢的强度有明显提高,但是与MA957有一定差距,抗拉强度有待改进;与MA957相比,14CrODS表现出良好的塑性,锻造可进一步提高14CrODS的高温塑性,但是锻造过程中的残余应力使材料低温拉伸时呈脆性,退火可去除残余应力,极大地提高14CrODS的塑性,使其远优于MA957。     

Preparation and In Vitro Evaluation of a New Fentanyl Patch Based on Acrylic/Silicone Pressure-Sensitive Adhesive Blends

In this study, the influence of the ratio of silicone (Si) to acrylic pressure-sensitive adhesive (PSA), polyvinyl pyrrolidone (PVP), and lauryl alcohol (LA)?%?(wt/wt) on the properties of a drug in adhesive patch containing 4%?(wt/wt) fentanyl as model drug was evaluated. The dependent variables selected were drug solubility, in vitro drug release in the platforms as well as adhesion properties including peel strength and tack value. By using the central composite design of Design Expert software, it was found that the effect of each factor was different, yet all had influenced dependent variables significantly (p?<?.05). Quadratic model generated for various response variables using backward regression analysis was found to be statistically significant (p?<?.05). It was deduced that the presence of PVP and Si displayed similar trends on drug solubility and release. Each role played by Si with LA and PVP in release rate was separately investigated, and it was found that the presence of PVP and LA in lowering the amount of drug released was more dominant compared with that of Si. The release patterns at the early and later stages follow the Higuchi and semiempirical models, respectively. Effect of PVP as well as Si and LA were similar on tack value. The influence of LA compared to peeling characteristics of Si system was more pronounced.     

Preparation of 14C by Irradiation of Aluminum Nitride in Nuclear Reactor

Properties of aluminum nitrides prepared by various methods were analyzed with respect to their use as nitrogen-containing materials for preparing ^{1 4}C by irradiation with thermal neutrons in nuclear reactor. It was found that carbon can be completely isolated from irradiated aluminum nitride using potassium dichromate oxidizing agent. Carbon-14 dioxide can be isolated from the gas mixture with nitrogen and nitrogen oxides formed during oxidation of irradiated nitride by passing through potassium permanganate and sodium hydroxide absorbing solutions.     

Heterogeneous Catalytic Synthesis of Organic Compounds Labeled with Hydrogen Isotopes without Using Solvents

Solid-phase procedures for hydrogenolysis, hydrogenation, and isotope exchange are described. The possibilities of the solid-phase method for deuterium or tritium labeling of organic compounds are demonstrated. The influence of the reaction conditions on the yield of the labeled products and on the degree of hydrogen isotope incorporation into them is considered. An attempt is made to rationalize the data obtained by processes occurring in the hydrogen isotope–catalyst–support–substrate system.     

CuCl14Pc/Y纳米复合材料的制备、表征及其催化性能的研究

用沸石合成法制备了ＣｕＣｌ_１４Ｐｃ/Ｙ分子筛纳米复合材料(简称为ＣｕＣｌ_１４Ｐｃ/ｎａｎｏ－Ｙ),考察了合成条件对纳米复合材料的粒度影响．用ＸＲＤ、ＩＣＰ、ＴＧ－ＤＴＡ、ＴＥＭ、ＦＴＩＲ、ＵＶ－ｖｉｓ及催化反应等对其性能作了表征．结果表明:铜酞菁(ＣｕＣｌ_１４Ｐｃ)经过水热晶化后,部分被分装在纳米Ｙ型分子筛的空腔中,其催化氧化性能较普通ＣｕＣｌ_１４Ｐｃ/Ｙ分子筛复合材料有很大提高．     

快淬Pr2Fe14B粘结磁体制备工艺优化研究

采用过快淬加后续晶化退火处理的方法,研究了快淬速度和晶化工艺对近正分单相快淬Pr2Fe14B粘结磁体磁性能的影响.发现快淬速度、晶化温度和晶化时间均对磁体的组织结构和磁性能有较大影响,以28 m@s-1速度快淬出的条屑,在655℃经10min的晶化处理,可获得最佳磁性能,用3.25wt%环氧树脂粘结的磁体磁性能为:Br=0.69T,Hci=497kA@m-1,Hcb=334kA@m-1,(BH)m=65kJ@m-3.     

长余辉发光材料Sr4Al14O25:Eu2+,Dy3+的制备

采用化学沉淀法制备了Sr4Al14O25:Eu2 ,Dy3 蓝绿色长余辉发光粉.通过XRD分析表明:经1100℃和1200℃煅烧制得的发光粉均为单一的Sr4Al14O25晶相,不含其它任何杂相,同时研究了硼酸的加入量对发光粉的物相变化和发射光谱的影响,通过场发射扫描电子显微镜分析了粉体的形貌和粒径.     

CuCl14Pc/Y纳米复合材料的制备、表征及其催化性能的研究

在沸石合成法制备了CuCl14Pc/Y分子纳米复合材料（简称为CuCl14Pc/nano-Y)，考察了合成条件对纳米复合材料的粒度影响，用XRD、ICP、TG－DTA、TEM、FTIR、UV－vis及催化反应等对其性能作了表征，结果表明，铜酞菁（CuCl14Pc)经过水热晶化后，部分被分装在纳米Y型分子筛的空腔中，其催化氧化性能较普通CuCl14Pc/Y分子筛复合材料有很大提高。     

Nd2Fe14B/α-Fe纳米复合永磁的制备和性能

用超声化学法制备纳米Fe颗粒包覆的Nd2Fe14B复合粉体,将其在Ar气保护下经放电等离子烧结(SPS),得到Nd2Fe14B/α-Fe纳米晶复合磁体.Fe名义质量分数为5%的烧结磁体具有较高的磁性能:Br=0.86 T,Hci=683.8 kA/m,(BH)max=95.92 kJ/m3.烧结前对复合粉末进行适当的高能球磨,能促进显微组织进一步细化,增强软磁相与硬磁相之间的交换耦合,使相同Fe含量和烧结工艺的磁体Br和(BH)max分别提高到0.94 T和113.6 kJ/m3.     

生物荧光标记菁染料的研究进展

近年来，菁染料作为功能性染料正不断拓展其应用范围，特别是在标记生物大分子中得到广泛的应用，由于菁染料有着光谱范围广，摩尔消化吸光系数高，较高的荧光量子产率以及高灵敏度等良好特性，它有可能取代传统的荧光标记染料，成为新一代的探针染料，本文主要对TO，Y 列及其二聚体染料和多甲川近红外系列菁染料两大类菁染料的一些结构，性质及其应用几方面进行了介绍。     

非晶Mg65-xNi21Pr14Agx合金电极的制备及其放电性能

用铜模喷铸法制备了非晶Mg65-x Ni21-Pr14Ag x合金,采用球磨方法细化了合金颗粒。系统研究了不同Ag含量对非晶合金电极充放电行为、放电容量、循环稳定性、高倍率放电等性能的影响规律。结果表明,Ag元素的添加改善了合金电极充/放电性能,随着Ag含量的增加,非晶合金电极的最大放电容量和循环稳定性均呈现先增大后减小的规律,其高倍率放电性能也有所提高,适量Ag的添加可明显改善非晶MgNi-Pr系合金的放电性能。     

Laws of Formation of Oxycarbide Layers on Titanium in Carbon- and Oxygen-Containing Media

We established the laws of changes in the phase composition of surface layers in the course of saturation of titanium from graphite in static argon atmosphere and dynamic vacuum (1.3–133.3 Pa) at 950–1100°C. We showed that the composition of the oxycarbide phase depends on the saturation temperature and oxygen partial pressure in the gaseous oxygen-containing environment.     

Low Temperature IR Study of Shape Transition in Carbon-, Silicon-and Germanium Tetrachlorides

The IR data in 20-296 K temperatures interval for carbon-, silicon- and germanium tetrachlorides are given. It is shown that the spectral picture of bands, appearing in higher frequencies region relatively to element-chlorine stretching, considerably changes at the temperature variation and therefore can be assigned to the vibrations of different molecular shapes. The interpretation of the obtained results based on the suggested model of transformation in the structure of tetrachlorides. This transformation leads to the arising of an active chlorine atom in molecules of element-tetrachlorides.     

Treatment of Gaseous Medium to Remove Radioactive Aerosols CsOH and Cs2MoO4 Labeled with Cesium-137

Radiochemistry - The process of the gas phase treatment to remove CsOH and Cs2MoO4 radioactive aerosols labeled with cesium-137 (hereinafter, 137CsOH and 137Cs2MoO4) was studied using a setup...     

低温精馏分离稳定同位素碳-13回顾与展望

概述了国际上稳定同位素碳-13的分离技术现状;分析了不同装置的技术特点;结合CO低温精馏技术关键及近年低温技术、化工技术的最新成果,从原料气制备工艺、换热器设计、新型填料设计、精馏塔结构、级联形式、能量组织利用等方面分析了低温精馏技术分离碳-13的技术创新途径.     

Preparation and evaluation of valsartan by a novel semi-solid self-microemulsifying delivery system using Gelucire 44/14

The aim of the present study was to develop a novel semi-solid self-microemulsifying drug delivery system (SMEDDS) using Gelucire^® 44/14 as oil with strong solid character to improve the oral bioavailability of poorly soluble drug valsartan. The solubility of valsartan in various excipients was determined, the pseudo-ternary phase diagram was constructed in order to screen the optimal excipients, and DSC analysis was performed to evaluate the melting point of SMEDDS. The optimal drug-loaded SMEDDS formulation was consisted of 30% Gelucire^® 44/14 (oil), 40% Solutol^® HS 15 (surfactant), and 30% Transcutol^® P (cosurfactant) (w/w) with 80?mg valsartan/g excipients. The average droplet sizes of the optimized blank and drug-loaded SMEDDS formulations were 26.20?±?1.43 and 33.34?±?2.15?nm, and the melting points of them were 35.6 and 36.8?°C, respectively. The in vitro dissolution rate of optimal semi-solid SMEDDS was increased compared with commercial capsules, resulting in the 2.72-fold and 2.97-fold enhancement of C_max and AUC_0–t after oral administration in rats, respectively. These results indicated that the novel semi-solid SMEDDS formulation could potentially improve the oral bioavailability of valsartan, and the semi-solid SMEDDS was a desirable system than the traditional liquid SMEDDS because it was convenient for preparation, storage and transportation due to semi-solid state at room temperature and melted state at body temperature.