Some Aspects on Preconcentration for Neutron Activation Analysis

A preconcentration method incorporated with neutron activation analysis was developed for the accurate determination of trace metals in biological and environmental samples. Bismuth diethyldithiocarbamate, thallium diethyldithiocarbarnate, and ammonium pyrrolidinedithiocarbamate were used as the preconcentration agents for three groups of metals. Trace metals were enriched and interfering elements such as Na, Br, P. K. etc. were removed simultaneously during the preconcentration process so that the sensitivity for each metal was greatly improved. Optimal conditions for sample digestion, group preconcentration of trace metals and neutron activation analysis of biological and environmental samples were discussed.     

The 1:2 Complex of Piperazine with Some Phenols:Hydrogen Bonding Pattern Involved in Transition States in Solution

Previous calorimetric and iR studiesl had showed that, in a system of secondary amineand unhindered phenol, hydrogen bonds of O--H---N and N--H---O concurred toappear. Fast proton exchange between proton donor and acceptor in solution is usualphenomenon 2-". Therefore, a novel model (Scheme l) for the I fZ complex of piperazine(Pip) respectively with phenol (Ph), 2-metylphenol (O-MPh), 4-metylphenol (P-MPh)(abbreviated generally as PiP' ZXPh) in solution is now established. As showed …     

Simultaneous structural and elemental nano-imaging of human brain tissue

Examining chemical and structural characteristics of micro-features in complex tissue matrices is essential for understanding biological systems. Advances in multimodal chemical and structural imaging using synchrotron radiation have overcome many issues in correlative imaging, enabling the characterization of distinct microfeatures at nanoscale resolution in ex vivo tissues. We present a nanoscale imaging method that pairs X-ray ptychography and X-ray fluorescence microscopy (XFM) to simultaneously examine structural features and quantify elemental content of microfeatures in complex ex vivo tissues. We examined the neuropathological microfeatures Lewy bodies, aggregations of superoxide dismutase 1 (SOD1) and neuromelanin in human post-mortem Parkinson''s disease tissue. Although biometals play essential roles in normal neuronal biochemistry, their dyshomeostasis is implicated in Parkinson''s disease aetiology. Here we show that Lewy bodies and SOD1 aggregates have distinct elemental fingerprints yet are similar in structure, whilst neuromelanin exhibits different elemental composition and a distinct, disordered structure. The unique approach we describe is applicable to the structural and chemical characterization of a wide range of complex biological tissues at previously unprecedented levels of detail.

Structural and chemical characterisation of microfeatures in unadulterated Parkinson''s disease brain tissue using synchrotron nanoscale XFM and ptychography.     

吡啶甲酰硫脲嘧啶衍生物的合成及生物活性

酰基硫脲类化合物及其吡啶取代产物不仅是重要的有机合成中间体 ,且有优良的杀虫 ,除草 ,抗病毒 ,及植物生长调节等功效[1 - 3] 。为了寻找高活性的新药物 ,本文采用亚结构连接法 ,将吡啶杂环引入到含取代嘧啶环的酰基硫脲中 ,合成了8个含取代嘧啶环的β (或γ )吡啶甲酰硫脲 4ａ～4ｈ ,结构经ＩＲ、1 ＨＮＭＲ、ＭＳ和元素分析表征。初步生物活性测定结果表明 :目标化合物高效抑制双子叶植物 (如油菜 )的生长 ,而对单子叶植物 (如玉米 )的生长具有一定的促进作用。目标化合物的合成路线为 :表 1　化合物 4ａ～ 4ｈ Ｔａｂ 1　Ｃｏｍｐｏｕ…     

A window-space-directed assembly strategy for the construction of supertetrahedron-based zeolitic mesoporous metal–organic frameworks with ultramicroporous apertures for selective gas adsorption

Despite their scarcity due to synthetic challenges, supertetrahedron-based metal–organic frameworks (MOFs) possess intriguing architectures, diverse functionalities, and superb properties that make them in-demand materials. Employing a new window-space-directed assembly strategy, a family of mesoporous zeolitic MOFs have been constructed herein from corner-shared supertetrahedra based on homometallic or heterometallic trimers [M₃(OH/O)(COO)₆] (M₃ = Co₃, Ni₃ or Co₂Ti). These MOFs consisted of close-packed truncated octahedral cages possessing a sodalite topology and large β-cavity mesoporous cages (∼22 Å diameter) connected by ultramicroporous apertures (∼5.6 Å diameter). Notably, the supertetrahedron-based sodalite topology MOF combined with the Co₂Ti trimer exhibited high thermal and chemical stability as well as the ability to efficiently separate acetylene (C₂H₂) from carbon dioxide (CO₂).

A series of supertetrahedron (ST)-based sodalite (sod)-topology zeolitic MOFs specimens ST-sod-MOFs featuring ultramicroporous square windows and a mesoporous sodcage have been synthesized via a window-space-directed assembly approach.     

聚合物支载的甘氨酸与Cu^2＋离子的络合性能

本文用N-（3-聚苯乙烯磺酰基-2-羟基丙基）甘氨酸为模型，研究了聚合物支载的氨基酸与Cu2 离子的络合作用性能。树脂与铜离子络合的介质最佳pH值在2～3之间。按照方程：－1n（1－F）=KTt处理求得吸附速率下数K288＝2．47X10－4sec－1。根据Boyd液膜扩散理论，这一吸附过程主要受液膜扩散控制。而且这个反应过程是一种Freundlish吸附过程。G=－30．91KJ／mole和S=129．90J／moleK表明，吸附反应是自发进行的。用斜率法和容量法求得树脂支载的氨基酸基因与铜离子之间的配位比为2:1。     

Fabrication of Active Horseradish Peroxidase Micropatterns with a High Resolution by Scanning Electrochemical Microscopy

We used a new reactive species OH^? to fabricate active horseradish peroxidase (HRP) micropatterns with a high resolution by scanning electrochemical microscopy (SECM) coupled with a carbon fiber disk electrode as the SECM tip. In this method, except for active HRP micropatterns predesigned other regions on a HRP‐immobilized substrate were deactivated by OH^? generated at the tip held at ?1.7 V in 1.0 mol/L KCl containing 2.0×10^?3 mol/L benzoquinone (BQ) (pH 8.0). The feedback mode of SECM with a tip potential of ?0.2 V was used to characterize the active HRP micropatterns in 1.0 mol/L KCl containing 2.0×10^?3 mol/L BQ and 2.0×10^?3 mol/L H₂O₂.     

PHOTOOXIDATION OF SOME ORGANIC COMPOUNDS CATALYZED BY DECATUNGSTATES

ＰＨＯＴＯＯＸＩＤＡＴＩＯＮ ＯＦ ＳＯＭＥ ＯＲＧＡＮＩＣ ＣＯＭＰＯＵＮＤＳ ＣＡＴＡＬＹＺＥＤ ＢＹ ＤＥＣＡＴＵＮＧＳＴＡＴＥＳ￥ＢｉｎＹＵＥ；ＳｉＳａｎＺＨＵ；ＧａｏＹａｎｇＸＩＥ；ＹｉＤｏｎｇＧＵ（ＤｅｐａｒｔｍｅｎｔｏｆＣｈｅｍｉｓｔｒ...     

含噻二唑的新型三氮唑化合物的合成、结构表征及生物活性研究

The two compounds 1-[1-（2＇,4＇-dichlorobenzoyl）-1-（3-phenylthiazoidin-2-ylidene）methyl]-1,2,4-triazole （3a） and 1-[1-（4＇-fluorobenzoyl）-1-（3-phenylthiazolidin-2-ylidene）methyl]-1,2,4-triazole （3b） were prepared by reaction of phenyl isothiocyanate, 1,2-dibromoethane with a-（1,2,4-triazol-1-yl）-substituted-acetylbenzene. Their structures were identified by means of elemental analysis, IR, and ^1H NMR spectra. The single crystal of compound 3b was also obtained. It crystallizes in triclinic system with space group P1 and a=0.9390（2） nm, b=0.9661（2） nm, c= 1.0929（2） nm, α=111.53（3）°, β= 100.46（3）°, γ= 102.08（3）°, Z=2, V=0.8647（3） nm^3, Dc= 1.407 g/cm^3,μ =0.213 mm^-1, F（000）=380, final R1=0.073. There is obvious potentially weak C-H…Y （Y=N, F, O） intermolecular interaction between the molecules in the crystal lattice, which stabilizes the crystal structure. The result of the biological test showed that the two compounds have certain fungicidal activities.