The radioprotective and prophylactic properties of biologically active substances prepared by supercritical fluid extraction from pine shoots

The radioprotective properties of a substance from pine shoots prepared by supercritical fluid extraction with carbon dioxide were studied for a model of an experimental bone-marrow radiation sickness form. Experiments were performed for white nonlinear mice. The CO₂ extract of pine shoots was shown to possess radioprotective properties. The extract was subjected to pre-clinical tests for Wistar line male rats with respect to its antiatherogenic and antioxidative action in the creation of experimental hyperlipemia.     

Determination of catalytic properties of TiO2 coatings using aqueous solution of coumarin: Standardization efforts

Many types of supported photocatalytic TiO₂ continue to be the subject of extensive development worldwide. Besides industrial production and practical use of the new photocatalytic materials, there is an increasing need for a simple and reliable procedure for characterization of photocatalytic activities of newly developed materials. The aim of our work was to develop a method for the determination of quantum yields of supported photocatalysts by employing an aqueous solution of a model organic compound and different thin TiO₂ films. Additionally, also a newly defined parameter, the so-called mass efficiency, was introduced as an advantageous way of defining the photocatalytic activities. Coumarin (CM) was found to be an appropriate candidate for being a probe molecule when the photocatalytic degradation mainly occurs via the HO radical-mediated mechanism. An advantage of using CM is easy determination of highly fluorescent 7-hydroxycoumarin (7OHC). Different TiO₂ films were deposited via sol–gel methods on soda-lime glass slides that were precovered with a thin SiO₂ film, and via the sedimentation process from aqueous suspensions. Aqueous solutions of CM were irradiated using 365 nm radiation in the presence of titania films. Although Degussa P25 films showed approximately four times higher degradation rates compared to the sol–gel processed, its quantum yield was not more than 2.5 times higher. This could be explained by higher absorbance of Degussa P25 films per amount of the catalyst compared to sol–gel films. Since no information on the absorption characteristics of the material per unit of mass of the catalyst is included within the calculation of quantum yield, mass efficiency is suggested for the evaluation of photocatalytic properties of the coatings. It is evident from the present study that it is obligatory to evaluate the photocatalytic efficiencies of different area densities of the same photocatalyst in order to properly characterize the material's efficiency.     

Nepethalates A and B: Two New Phthalate Derivatives from Nepeta clarkei

The structure elucidation of two new phthalate derivatives named nepethalates A ( 1 ) and B ( 2 ) is reported. Both of these secondary metabolites were isolated from the MeOH extract of Nepeta clarkei. HR‐EI‐MS, IR and UV absorption spectrometry, and NMR experiments including COSY, HMQC, and HMBC were used for the determination of the structures and complete ¹H‐ and ¹³C‐NMR assignments.     

Ajuganane: a new phenolic compound from Ajuga bracteosa

Phytochemical investigation of Ajuga bracteosa Wall ex Benth. (Labiatae) resulted in the isolation of a new phenolic compound, ajuganane (1) and three known compounds, 3,4'-dihydroxy-3,6,7-trimethoxyflavone, 7-hydroxy-3,6,3',4'-tetramethoxyflavone and ursolic acid. The structure of the new compound was elucidated by detailed spectroscopic (1H, 13C NMR, COSY, HMQC, HMBC), and HR-EI-MS analysis.     

Direct Cu‐Catalyzed Allylic Acetoxylation of Δ5‐Steroids at 7‐Position

The efficiency and selectivity of Cu‐catalyzed allylic acetoxylation of alkene in different solvent systems is improved by the presence of different metallic salts in the reaction medium. The methodology is particularly well employed for the direct allylic acetoxylation of Δ⁵‐steroids at 7‐position, for which the resulting acetoxylated product obtained was exclusively α‐isomer. Excellent yield was achieved (up to 90%) under optimized conditions, while significantly reducing the costs and environmental hazards and increasing the yield as compared to the other previously reported methods.     

Weighted-density approaches for polymer structure at solid–polymer interfaces

Weighted-density approximations (WDAs), which are based on the weighting function for the second-order direct correlation functions (DCFs) of the uniform polymeric fluids, have been developed to investigate the structural and thermodynamic properties of polymer melts at interfaces. The advantage is the simplicity of calculation of the weighting functions and their accuracies in the applications. They were applied to study the local density distributions and adsorption isotherms of the freely jointed tangent hard-sphere chain, Yukawa chain, and hard-sphere chain mixture in slit pores. The polymer reference interaction model (PRISM) integral equation with the Percus–Yevick (PY) closure has been used to calculate the second-order DCF of the polymeric fluids required as inputs. The mean-field approximation (MFA) has been used to calculate the weighting function for the attractive contribution of a freely jointed tangent Yukawa chain fluid, having attraction among the beads. The calculated results show that (i) for the freely jointed tangent hard-sphere chain, the present theory is in excellent agreement with the computer simulations over a wide range of chain lengths and bulk densities, (ii) the WDA approach for the attraction provides an accurate method for the local density distributions of a freely jointed tangent Yukawa chain fluid, and that (iii) the present theory also yields a reasonably good result for the structural properties of the freely jointed hard-sphere chain mixtures composed of the chain and monomer.     

Dependence of the ordering degree and thermochemical characteristics of chitin and chitosan on their biological origin

Standard enthalpies of combustion and formation were studied, along with the enthalpy of interaction of chitin and chitosan of different origins with water. The concentration of the water phase solution in chitin and chitosan saturated at 273 K was determined by calorimetry from the enthalpy of melting of the water excess phase. The dependence of these properties on the source, molecular mass, and degree of ordering of polysaccharides was demonstrated.     

Blue upconversion luminescence of CaMoO4:Li+/Yb3+/Tm3+ phosphors prepared by complex citrate method

Li⁺/Tm³⁺/Yb³⁺ co-doped CaMoO₄ upconversion (UC) phosphor was prepared by complex citrate-gel method and UC luminescence properties were investigated. Li⁺/Tm³⁺/Yb³⁺ co-doped CaMoO₄ has intense blue emission induced by ¹G₄??³H₆ transition at 476?nm that is improved 10 times more than that of Li⁺ undoped sample and weak red emission at 647 nm generated by ³F₂??³H₆ transition under excitation at 980?nm. The optimum doping concentration of Li⁺ ions was investigated and UC mechanism of Li⁺/Tm³⁺/Yb³⁺ co-doped CaMoO₄ was discussed in detail.