Synthesis and Systematic Structural Analysis of Cationic Half-Sandwich Ruthenium Chalcogenocarbonyl Complexes

Although the chemistry of transition-metal complexes with carbonyl (CO) and thiocarbonyl (CS) ligands has been well developed, their heavier analogues, namely selenocarbonyl (CSe) and tellurocarbonyl (CTe) complexes remain scarce. The limited availability of such CSe and CTe complexes has so far hampered our understanding of the differences between such chalcogenocarbonyl (CE: E=O, S, Se, Te) ligands. Herein, we report the synthesis and properties of a series of cationic half-sandwich ruthenium CE complexes of the type [CpRu(CE)(H₂IMes)(CNCH₂Ts)][BAr^F₄] (Cp=η⁵-C₅H₅⁻; H₂IMes=1,3-dimesitylimidazolin-2-ylidene; Ar^F=3,5-(CF₃)₂C₆H₃). A combination of X-ray diffraction analyses, NMR spectroscopic analyses, and DFT calculations revealed an increasing π-accepting ability of the CE ligands in the order O<S<Se<Te. A variable-temperature NMR analysis of the thus obtained chiral-at-metal CE complexes indicated high stereochemical stability.     

Biosafety evaluation and quantitative determination of poly(hexamethylene biguanide) (PHMB) coated on cellulosic fabrics by Kubelka–Munk equation

Cellulose - It is difficult to directly determine the quantity of cationic finishing agents on the surface of cellulosic fabrics. Herein, we report a direct and feasible method by...     

Hydrophilic–oleophobic coatings on cellulosic materials by plasma assisted polymerization in liquid phase and fluorosurfactant complexation

Materials with hydrophilic–oleophobic properties are of relevance due to their application to different fields such as self-cleaning coatings, liquid–liquid separation membranes and functional textiles for different technical applications. In this work, hydrophilic–oleophobic coatings have been deposited on cellulosic materials (filter paper and bleached cotton) by means of plasma assisted polymerization of acrylic acid solutions in water followed by cationic fluorosurfactant complexation. Chemical composition of the coatings on cellulosic materials was characterized by means of FTIR–ATR and XPS whereas their morphology was studied by SEM. Hydrophilic–oleophobic behavior was characterized by means of contact angle and wetting time. Additionally wetting properties of cationic, anionic and non-ionic surfactant solutions on the hydrophilic–oleophobic coatings were used to characterize the polyelectrolyte electrostatic forces upon the functionalized layer.     

Invariant ideals of twisted crossed products

We will prove a result concerning the inclusion of non-trivial invariant ideals inside non-trivial ideals of a twisted crossed product. We will also give results concerning the primeness and simplicity of crossed products of twisted actions of locally compact groups on -algebras. Received: 25 January 2002; in final form: 22 May 2002/Published online: 2 December 2002 This work is partially supported by Hong Kong RGC Direct Grant.     

Ultra-low temperature transport anomalies in air annealed Pt

Measurements of electrical resistivity ? and thermoelectric ratio G on air annealed reference grade Pt samples from 4 K down to 40 mK reveal ultra-low temperature anomalies in both properties. The observed T² components of ? are consistent with values obtained by previous investigators from measurements above 1 K.     

Harmonic Functions on Homogeneous Spaces

 Given a locally compact group G acting on a locally compact space X and a probability measure σ on G, a real Borel function f on X is called σ-harmonic if it satisfies the convolution equation . We give conditions for the absence of nonconstant bounded harmonic functions. We show that, if G is a union of σ-admissible neighbourhoods of the identity, relative to X, then every bounded σ-harmonic function on X is constant. Consequently, for spread out σ, the bounded σ-harmonic functions are constant on each connected component of a [SIN]-group and, if G acts strictly transitively on a splittable metric space X, then the bounded σ-harmonic functions on X are constant which extends Furstenberg’s result for connected semisimple Lie groups.     

Integrated metabolomics analysis of the effect of PPARδ agonist GW501516 on catabolism of BCAAs and carboxylic acids in diabetic mice

The peroxisome proliferator-activated receptor(PPARδ) agonists are reported to improve insulin sensitivity,reduce glucose levels,and alleviate dysfunctional lipid metabolism in animal models of type 2 diabetes mellitus.However,the underlying mechanisms remain incompletely understood.Metabolism plays an essential role in the biological system.Monitoring of metabolic changes in response to disease conditions or drug treatment is critical for better understanding of the pathophysiological mechanisms.In this study,metabolic profiling analysis by gas chromatography-mass spectrometry integrated with targeted analysis by liquid chro matography-mass spectrometry was carried out in plasma samples of db/db diabetic mice after six-week treatment of PPARδ agonist GW501516.GW501516 treatment significantly altered levels of metabolites,such as branched-chain amino acids(BCAAs),BCAA metabolites(3-hydroxyisobutyric acid and 3-hydroxyisovaleric acid),long-chain fatty acids,uric acid and ketone bodies(3-hydroxybutyric acid and 2-hydroxybutyric acid) which are all associated with the impaired systemic insulin sensitivity.The pre sent results indicate the beneficial effect of PPARδ agonist in alleviating insulin resistance of diabetic mice by favorably modulating metabolic profile,thus providing valuable information in understanding the therapeutic potential of PPARδ agonists in correcting metabolic dysfunction in diabetes.     

Some permanence properties of C-unique groups

We will study some permanence properties of C^*-unique groups in details. In particular, normal subgroups and extensions will be considered. Among other interesting results, we prove that every second countable amenable group with an injective finite-dimensional representation (not necessarily unitary) is a retract of a C^*-unique group. Moreover, any amenable discrete group is a retract of a discrete C^*-unique group.