Etude du Systeme Ternaire Se-Te-Sn

This work is a part of the systematic study of the ternary based chalcogenides systems. The aim is to determine the phase equilibrium, and to determine the limits of the phase area. This is done in view to perfecting knowledge of elaboration conditions for new materials and to study of their physical properties. Few works have been devoted to the study of the ternary system Se-Te-Sn, only the cross section SnSe-SnTe has been studied [1] and [2]. The experimental study by DTA, DSC and X-ray diffraction on powder performed at room temperature, exhibits a miscibility gap in the liquid state which narrows as it goes through the Sn-Se binary system. Three cross sections behave as ‘quasi-binary‘ system and six ternary invariants have been exhibited: three ternary eutectics and three ternary quasi-peritectics. This revised version was published online in July 2006 with corrections to the Cover Date.     

Reaction of Tetracopper(I)-Phosphonitocavitand with PhSeSiMe3: Synthesis and Structure of a Polyanionic Cluster [pyH]6[(CuCl)9(μ3-SePh)5(μ4-SePh)]

Treatment of tetracopper(I)-phosphonitocavitand [1·Cu₄(μ-Cl)₄(μ₄-Cl)] (2) (1 = tetraphosphonitocavitand [rccc-2,8,14,20-tetrakis-(iso-butyl)-phosphonitocavitand (C₄₄H₄₈O₈P₄Ph₄)]) with PhSeSiMe₃ in THF at low temperature afforded a novel polyanionic cluster [pyH]₆[(CuCl)₉(μ₃-SePh)₅(μ₄-SePh)] (4) as a major product along with a new tetracopper(I)-phosphonitocavitand (3) with a centered μ₃-Cl. Molecular structure of anionic cluster in 4 consists of six PhSe⁻ bridging ligands containing five μ₃-SePh and one exceptional μ₄-SePh bridging nine copper atoms, of which eight copper atoms have trigonal coordination geometry and the other has distorted tetrahedral geometry. Dedicated to Professor Han-Qin Liu on the occasion of his 70th birthday.     

Topological effect on MO energies,IV. The total π-electron energy ofS- andT-isomers

A novel general property of theS- andT-isomers (a concept which has been introduced and elaborated elsewhere^{1, 2}) of alternant hydrocarbons is demonstrated, namely that due to the HMO total -electron energy theS-isomer should always be more stable than theT-isomer. Some other classes of conjugated isomers are also constructed, for which similar inequalities are derived.

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Topologischer Effekt bei MO-Energien, 4. Mitt.: Die -Elektronen-Gesamtenergie vonS- undT-Isomeren

Zusammenfassung Es wird allgemein gezeigt, daß bei einemS-T-Isomerenpaar (beschrieben in^{1, 2}) eines alternierenden Kohlenwasserstoffes infolge der HMO -Elektronen-Gesamtenergie dasS-Isomere stets stabiler sein sollte als dasT-Isomere. Weitere Klassen konjugierter Isomere werden konstruiert und ähnliche Ungleichungen angegeben.

     

Diacetylenic Derivatives of Fe2(CO)6(μ-EE′): Spectroscopic Investigations of Fe2(CO)6{μ-EC(H) = C(C≡ CMe)E′} (E = E′, E ≠ E′; E, E′ = S, Se, Te)

The diacetylenic adducts, Fe₂(CO)₆{-EC(H) = C(C CMe)E} (E = E, E E; E, E = S, Se, Te) (1–8) have been obtained from the room temperature stirring of Fe₂(CO)₆(-EE) with HC CC CMe in methanol solvent containing sodium acetate. Compounds 1–8 have been characterized by IR and multinuclear NMR (¹H, ¹³C, ⁷⁷Se, and ^l25Te) spectroscopy. Trends in the chemical shifts of ⁷⁷Se and ¹²⁵Te NMR spectra of Fe₂(CO)₆{-EC(H) = C(C CMe)E} with a variation of EE are discussed.     

Quo Vadis total reflection X-ray fluorescence?

The multielement trace analytical method ‘total reflection X-ray fluorescence’ (TXRF) has become a successfully established method in the semiconductor industry, particularly, in the ultra trace element analysis of silicon wafer surfaces. TXRF applications can fulfill general industrial requirements on daily routine of monitoring wafer cleanliness up to 300 mm diameter under cleanroom conditions. Nowadays, TXRF and hyphenated TXRF methods such as ‘vapor phase decomposition (VPD)-TXRF’, i.e. TXRF with a preceding surface and acid digestion and preconcentration procedure, are automated routine techniques (‘wafer surface preparation system’, WSPS). A linear range from 10⁸ to 10¹⁴ [atoms/cm²] for some elements is regularly controlled. Instrument uptime is higher than 90%. The method is not tedious and can automatically be operated for 24 h/7 days. Elements such as S, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Br, Sn, Sb, Ba and Pb are included in the software for standard peak search. The detection limits of recovered elements are between 1×10¹¹ and 1×10⁷ [atoms/cm²] depending upon X-ray excitation energy and the element of interest. For the determination of low Z elements, i.e. Na, Al and Mg, TXRF has also been extended but its implementation for routine analysis needs further research. At present, VPD-TXRF determination of light elements is viable in a range of 10⁹ [atoms/cm²]. Novel detectors such as silicon drift detectors (SDD) with an active area of 5 mm², 10 mm² or 20 mm², respectively, and multi-array detectors forming up to 70 mm² are commercially available. The first SDD with 100 mm² (!) area and integrated backside FET is working under laboratory conditions. Applications of and comparison with ICP-MS, HR-ICP-MS and SR-TXRF, an extension of TXRF capabilities with an extremely powerful energy source, are also reported.     

The American (USA) perspective six years after implementation of CLIA'88 (Federal) regulations

 On September 1, 1992 all testing sites in the United States were required to comply with the Clinical Laboratory Improvement Amendments of 1988 (CLIA'88). These regulations, based on both total quality management (TQM) and continuous quality improvement (CQI) principles, reshaped the environment for more than 90% of laboratories. CLIA'88 represented a revolutionary change by imposing universal, uniform regulations based on test complexity for all sites examining materials derived from the human body for the purpose of providing information for the diagnosis, prevention, or treatment of disease. CLIA'88 specifies minimum requirements for personnel, quality control, and proficiency testing (PT). In addition, laboratories are required to follow manufacturers' directions and comply with other specified good laboratory practices. PT is mandated for most of the frequently run analyses and quality assurance requirements integrate the principles of CQI as well as TQM into the regulatory process. Biannual inspection is integral to CLIA'88, however, laboratories can choose other federally approved ("deemed") professional organizations, such as the Commission on Office Laboratory Accreditation, the College of American Pathologists, or the Joint Commission on Accreditation of Healthcare Organization, having standards that meet or exceed those of CLIA'88. CLIA'88 has still not been finalized. This article discusses the impact and changes since CLIA's implementation in 1992. Received: 5 October 1998 · Accepted: 20 October 1998     

硒芳香杂环化合物的光谱和电化学性质

用紫外光谱，荧光光谱和循环伏安法研究了含硒芳香杂环化合物（苤硒脑）在不同溶剂中的谱学和电化学性质，对不同分子结构或取代基的苤硒脑化合物的性质进行了比较，并初步探讨了溶剂对苤硒脑化合物谱学性质的影响规律。     

An iterative acetylene-epoxide coupling strategy for the total synthesis of longimicin C

Longimicin C, a naturally occurring annonaceous acetogenin possessing a C₂-symmetrical bis-THF moiety and a short hydrocarbon chain between its THF-containing region and a terminal γ-lactone, was synthesized for the first time. The total synthesis was successfully achieved by an iterative acetylene-epoxide coupling strategy. d-Mannitol was used to establish the bis-THF-containing segment, in which the additional stereochemistries were introduced by Sharpless dihydroxylations and intramolecular Williamson etherifications. Regioselective epoxide-openings by the appropriate terminal acetylenes allowed coupling and elaboration of all four fragments including the introduction of three essential hydroxyls into the proper sites of the target skeleton.     

细胞呼吸爆发的微量量热学研究

The heat production of Wistar rat polymorphonuclear leukocytes (PMN) was measured by an LKB 2277 Thermal Activity Monitor. When PMN were activited with phorbol-12-myristate13-acetate (PMA), the respiratory burst was recorded by greatly incr eased heat production. Experiment was also carred out in the present of the inhibitor, Total Flavonoids of Lycium Barbarum L. (TFL). The respiratory burst heat production peak was disappeared, but the heat production curve was higher than that of PMA because TFL increased the metabolic activities of PMN.