Recent advances in theoretical models of respiratory mechanics

As an important branch of biomedical engineering, respiratory mechanics helps to understand the physiology of the respiratory system and provides fundamental data for developing such clinical technologies as ventilators. To solve different clinical problems, researchers have developed numerous models at various scales that describe biological and mechanical properties of the respiratory system. During the past decade, benefiting from the continuous accumulation of clinical data and the dramatic progress of biomedical technologies (e.g. biomedical imaging), the theoretical modeling of respiratory mechanics has made remarkable progress regarding the macroscopic properties of the respiratory process, complexities of the respiratory system, gas exchange within the lungs, and the coupling interaction between lung and heart. The present paper reviews the advances in the above fields and proposes potential future projects.     

Synthesis, Structure and Thermal Behavior of a New Coordination Polymer Based on Mixed Pyrazine-2-carboxylate and Oxalate Ligands

Abstract  

A new 4d–4f coordination polymer, [AgGd(pyzc)₂(ox)·H₂O)] (1) [pyzc = Pyrazine-2-carboxylate, ox = oxalate] has been successfully synthesized under hydrothermal conditions and structurally determined by single-crystal X-ray diffraction, and characterized by elemental analysis, infrared spectroscopy, thermogravimetric analysis and power X-ray diffraction. Single-crystal X-ray analysis reveals that it crystallizes in the monoclinic space group P2 ₁ /c with a = 10.0746(1) ?, b = 18.642(1) ?, c = 8.0525(2) ?, β = 112.470(1)°, Mr = 617.34, Z = 4, V = 1505.6(2) ?³, μ = 5.732, F(000) = 1164. The Gd(III) ion is nine-coordinated by two O-donors and two N-donors of two different chelating pyzc ligands, four O-donors of two different chelating oxalate ligands, and one O-donor of another carboxylate group of one pyzc ligand. The compound represents a 3D microporous polymeric network constructed by gadolinium–oxalate chains and Ag-pyzc subunits.     

Cation radical induced cycloaddition reaction between aryl imines and ethyl diazoacetate

The reaction of ethyl diazoacetate with aryl imines can be initiated by persistent cation radical salt tris(4-bromophenyl)aminium hexachloroantimonate, giving exclusively cis-aziridine carboxylates.     

Radical cation salt induced Povarov reaction between iminoethyl glyoxylate and N-vinylamides: synthesis of quinoline-2-carboxylate derivatives

A domino process between iminoethyl glyoxylate and N-vinylamides was achieved under the catalytic radical cation salt induced conditions, producing a series of quinoline-2-carboxylates. N-Vinylamides were involved as an acetylene equivalent. A possible mechanism was proposed to rationalize the formation of the products.     

Synthesis and Photophysics of Novel Soluble Polymeric Zn Metal Complex Based on Bis(8-hydroxyquinoline) Groups with Benzene Unit

A novel ligand: 2,2′‐(1,3‐phenylenedivinylene)bis‐8‐hydroxyquinoline (m‐B8QPH) ( 4 ) and the corresponding polymeric metal complex Zn ( m‐B8QPH ) ( 5 ) were designed and synthesized in a convenient way. The luminescence properties of the compounds Zn ( m‐B8QPH ) ( 5 ) and Zn(p‐B8QPH) ( 9 ) were investigated by UV‐vis and fluorescence spectra in DMF at room temperature. The experimental results showed that the polymeric complexes 5 and 9 emitted yellow luminescence at 578 and 554 nm in DMF solution. The polymeric complex 5 has demonstrated good solubility in common organic solvents and good thermal stability with high T_g: 261°C. Furthermore, the molecular interactions of 5 with fullerene (C₆₀) and fulleropyrrolidine containing 3,5‐bis(trifluoromethyl)benzene ( 11 ) were also investigated, which indicated the metal dye 5 can be used as new fluorescent probe.     

On the relative stability of the crystal structures of iron

Iron has ab.c.c, structure below 1183GK and above 1670GK In between it has anf.e.c, structure. In this paper the free enthalpy of ab.e.c, lattice and af.c.c lattice is calculated from an interatomic potential of the Morse type. The parameters of the Morse potential are considered as functions of temperature and their values are determined from macroscopic measurements of the lattice constant, the enthalpy and the entropy. The calculated free enthalpies exhibit intersections that correspond to the observed phase transitions. The intersections occur at temperatures which are close to the observed transition temperatures.     

Lysophosphatidylcholine—biomarker of Metformin action: studied using UPLC/MS/MS

An UPLC/MS/MS based metabonomic method was developed and applied to the elucidation of biomarker of metformin action. The plasma metabolite profiling in healthy volunteers before and after per os metformin was determined with UPLC/MS/MS and analyzed by using multivariate statistics. Significant difference in endogenous metabolite profiles was revealed before and after administration of metformin. Four biomarkers found were lysophosphatidylcholines (LPCs), and their structures were tentatively identified to be 16:0 LPC, 18:0 LPC, 18:1 LPC and 18:2 LPC according to the molecular ions information and corresponding fragments of product ion scan. Lysophosphatidylcholine in blood may be involved in metformin treatment. Copyright © 2009 John Wiley & Sons, Ltd.     

拓扑遍历映射的一些性质

本文研究拓扑遍历映射.指出对于由不可约方阵所决定的符号空间有限型子转移而言,或紧致交换群的仿射变换及线段上连续自映射而言,拓扑遍历与拓扑可迁这两个概念是一致的.同时还通过例子,指出拓扑遍历是不同于拓扑可迁与拓扑混合的概念.     

电流型大面积PIN探测器

研制了灵敏区面积为40,50和60mm,耗尽层厚度为200—300μm的电流型大面积薄型PIN半导体探测器,并对其物理性能进行了测量.测试和应用表明,这些探测器性能稳定,漏电流符合使用要求.与市场上的大面积PIN半导体探测器相比,这些探测器主要在几百伏偏压下工作在电流模式,但也可用于计数模式,而目前的商用产品仅适用于计数测量. 关键词： 半导体探测器 大面积 电流型