Tl2Te and its relationship with Tl5Te3

The crystal structure of Tl₂Te, dithallium telluride, has been determined by single‐crystal X‐ray diffraction. The analysis of the structure shows that this compound is the first known representative of a new crystal structure type. The structural relationship with the related Tl₅Te₃ phase is discussed.     

Catalytic enantioselective conjugate addition of dialkylzinc reagents to N-substituted-2,3-dehydro-4-piperidones

The first, highly enantioselective, copper/phosphoramidite-catalyzed conjugate addition of dialkylzinc reagents to N-substituted 2,3-dehydro-4-piperidones is described.     

Extraction chromatography using chelating agents

The separation of Zn?Cd, Ag?Hg, Cd?Ag and Pb?Bi?Po by extraction chromatography in the system dithizone-carbon tetrachloride is reported. It is shown that it is possible to calculate optimum conditions for the separation of the metals from the extraction constants of the metal chelates and the stability constants of the metal complexes with masking agents.     

Hypercharged anomaly mediation

We show that, in string models with the minimal supersymmetric standard model residing on D-branes, the bino mass can be generated in a geometrically separated hidden sector. Hypercharge mediation thus naturally teams up with anomaly mediation. The mixed scenario predicts a distinctive yet viable superpartner spectrum, provided that the ratio alpha between the bino and gravitino mass lies in the range 0.05 < or = |alpha| < or = 0.25 and m(3/2) > or = 35 TeV. We summarize some of the experimental signatures of this scenario.     

OXYGEN QUENCHING OF CHLOROPHYLL FLUORESCENCE IN CHLOROPLASTS

Abstract— Three phases of chlorophyll a fluorescence quenching by O₂ are observed in green plants. The effects of various inhibitors on photosynthetic partial processes in chloroplasts were investigated in attempts to (1) localize the O₂-quenching sites and (2) assess possible physiological significance of O₂-quenching. Our results localize the most sensitive (and presumably functionally important) phase to a site between plastoquinone and the photosystem I acceptor, chlorophyll (P₇₀₀), possibly plastocyanin. It is suggested that PC may transfer electrons to oxygen in addition to P₇₀₀.     

Organic–inorganic nanocomposite films made from polyurethane dispersions and colloidal silica particles

Polyurethane/silica nanocomposites were prepared by solution blending of polyurethane water dispersion (PUD) based on polycarbonate macrodiol with colloidal silica aqueous sol LUDOX TMA. Because of mixing PUDs made from linear polyurethane with the nanofiller, only physical polymer/filler type of interface formed by hydrogen bonds was obtained. As a result the materials were possible to reuse after dissolution in acetone followed by dispersion in water. The effect of colloidal silica content on mechanical, thermal, morphological, and swelling properties of obtained films was tested by tensile test, dynamic mechanical thermal analysis, thermogravimertic analysis, scanning electron microscopy, atomic force microscopy, and swelling analyses. The nanocomposites were classified in three groups differing in the internal structure and functional properties: organic matrix filled with inorganic nanofiller (up to 10 wt% of silica), bicontinous systems (25 and 32 wt% of silica) and inorganic matrix filled with polyurethane (50 and 60 wt% of silica). Only small amount of colloidal silica (up to 10 wt%) improves thermo-mechanical properties, smoothes the materials, and suppresses extent of swelling without changing of the films transparency.     

The first platinum(IV) complexes involving aromatic cytokinins or cyclin-dependent kinase inhibitors derived from 6-benzylaminopurine: X-ray structures of

A series of Pt(IV) complexes with cytokinins or CDK-inhibitors derived from 6-benzylaminopurine (Bap) of the composition [Pt^IV(LH⁺)Cl₅] (1–14), where LH⁺ stands for protonated form of the Bap derivative (1–12), Boh = 6-(benzylamino)-2-[(3-hydroxypropyl)amino]-9-isopropylpurine, bohemine (13) and Ros = 6-(benzylamino)-2-[(1-hydroxymethylpropyl)amino]-9-isopropylpurine, roscovitine (14), have been prepared.They have been fully characterized by microanalysis, conductivity, FT-IR, ¹H, ¹³C, ¹⁵N and ¹⁹⁵Pt NMR and ES+ mass spectroscopy.It has been found that the cytokinin molecule is coordinated via N9 atom to platinum(IV) and N1, N7-protonated in case of complexes 1–12, and N7 coordinated and N1-protonated in case of complexes with CDK inhibitors (13 and 14).Predicted molecular geometries of the complexes have been supported by DFT calculations at the B3LYP level with the 6-311+G^**/LANL2DZ and aug-cc-pVDZ/LANL2DZ basis sets.All of the compounds have been tested in vitro for their cytotoxicity against four human cancer cell lines: malignant melanoma (G361), osteogenic sarcoma (HOS), chronic myelogenous erythroleukemia (K562) and breast adenocarcinoma (MCF7).The best result has been achieved for complex 14, where IC₅₀ = 17 μM against K562. The molecular structures of two ionic pair compounds have been determined by a single crystal X-ray analysis.     

Synthesis and Reactivity of [PdCl(terpy)]Cl

 [PdCl(terpy)]Clċ3H₂O has been synthesized both by interaction of [PdCl₄]²⁻ and cis-[Pd(DMSO)₂Cl₂] with terpy (2,2^′:6^′,2^′′-terpyridine). Complex formation of [PdCl(terpy)]⁺ with L-cysteine, S-methyl-L-cysteine, and L-methionine was studied as a function of temperature (298–308 K) using of stopped-flow spectrophotometry in methanol-water (95:5 (v/v)). The ionic strength and acidity of the solutions were adjusted to 0.10 molċdm⁻³ with CH₃SO₃H. The second-order rate constant for the reaction of [PdCl (terpy)]⁺ with L-cysteine amounts to 9.60±0.5 M ⁻¹s⁻¹. L-Methionine and S-methyl-L-cysteine are unreactive under the same experimental conditions. The entropy of activation is strongly negative, which is compatible with an associative mechanism.     

Treatment of spent NTA-based decontamination solutions

This study deals with potential treatment of spent NTA-containing decontamination solutions for final disposal. The method proposed is based on the degradation of organic substances followed by the separation of radionuclides. The influence of various parameters (pH value, irradiation time, temperature, catalyst amount, type and various combinations of catalysts) on photocatalytic degradation of NTA has been studied. Photo-Fenton reagent (Fe³⁺/H₂O₂) as a homogenous catalyst was found to be much more efficient than the TiO₂-based heterogeneous catalyst Degussa P25. Under optimum conditions NTA in a simulant of a spent decontamination solution without or with hydrazine could be degraded within 5 or 9 hours, respectively. The study of sorption properties of a series of absorbers revealed that radiostrontium and radiosilver can be effectively removed from the simulant of a spent decontamination solution even in the presence of NTA, while total NTA degradation is necessary for effective radiocobalt separation.