Analytical characterization of some pyrazolones and their copolymers with some vinyl compounds

Some new pyrazolones have been synthesized and their copolymers with styrene, methylmethacrylate and methacrylic acid prepared. The pyrazolones and their styrene and methylmethacrylate copolymers are insoluble in water but form chelate complexes with some alkaline-earth and transition metal ions. The water-soluble methacrylic acid copolymers do not form complexes with these elements, however, probably because of hydrogen-bonding of the chelating groups to the methacrylic acid carboxyl groups. Special attention was paid to the complexation of Au(III), which was assumed to proceed mainly through the nitrogen atoms of the pyrazolone ring.     

Spirodepressolide: an unusual bis-norsesquiterpene lactone from Achillea depressa Janka

A new bis-norsesquiterpene lactone, spirodepressolide (1), has been isolated from the aerial parts of Achillea depressa Janka and its structure determined by spectroscopic methods to have a new 4-methyl-7-methylethyl-spirobicyclo[4,4]nonane skeleton.     

Screening for C283Y gamma-sarcoglycan mutation in a high-risk group of Bulgarian Gypsies: evidence for a geographical localization and a non-random distribution among Gypsy subgroups

Limb-girdle muscular dystrophy type 2C (LGMD2C) is an autosomal recessive disorder caused by mutations in the gamma-sarcoglycan gene. A 'private' Gypsy C283Y mutation was detected in this gene. Recently, a number of LGMD2C-affected families belonging to a Xoroxane Gypsy group have been detected in eastern Bulgaria and all of these cases were due to the same mutation. We have screened 300 unrelated individuals of reproductive age from this high-risk Xoroxane Gypsy group, settled in Sliven. The genetic test by PCR-SSCP analysis for the C283Y mutation revealed a carrier frequency of 7.7%. The screened sample was ethnically not homogeneous. It was divided in ethnonym groups on the basis of social and economic status, language characteristics and trades. We found that the C283Y was not randomly distributed among the Gypsy subgroups. The disease seemed to be limited to the Xoroxane Gypsy group and geographically localized in eastern Bulgaria.     

Nitrogen adsorption and thin surface nitrides on Cu(1 1 1) from first-principles

Experimental studies of nitrogen adsorbed on a Cu(1 1 1) surface show that the surface layer undergoes a reconstruction to form a pseudo-(1 0 0) structure. We use ab initio techniques to demonstrate the theoretical stability of this reconstructed surface phase over a range of conditions. We systematically investigate the chemisorption of N on the Cu(1 1 1) surface, from 0.06 to 1 ML coverage. A peculiar atomic relaxation of N atoms for 0.75 ML is identified, which results in the formation of a (metastable) “N-trimer cluster” on the surface. We have also investigated surface nitride formation, as suggested from experiments. A surface nitride-like structure similar to the reported pseudo-(1 0 0) reconstruction is found to be highly energetically favored. Using concepts from “ab initio atomistic thermodynamics”, we predict that this surface nitride exists for a narrow range of nitrogen chemical potential before the formation of bulk Cu₃N.     

CATALOGIC 301C model – validation and improvement

In Europe, REACH legislation encourages the use of alternative in silico methods such as (Q)SAR models. According to the recent progress of Chemical Substances Control Law (CSCL) in Japan, (Q)SAR predictions are also utilized as supporting evidence for the assessment of bioaccumulation potential of chemicals along with read across. Currently, the effective use of read across and QSARs is examined for other hazards, including biodegradability. This paper describes the results of external validation and improvement of CATALOGIC 301C model based on more than 1000 tested new chemical substances of the publication schedule under CSCL. CATALOGIC 301C model meets all REACH requirements to be used for biodegradability assessment. The model formalism built on scientific understanding for the microbial degradation of chemicals has a well-defined and transparent applicability domain. The model predictions are adequate for the evaluation of the ready degradability of chemicals.     

Inhibitory effect of lactone fractions and individual components from three species of the Achillea millefolium complex of Bulgarian origin on the human neutrophils respiratory burst activity

Achillea species are widely used in folk medicine for treatment of inflammatory diseases. The inhibitory effect on the human neutrophils respiratory burst activity of total extracts, their fractions and some main constituents of the flower heads from Achillea asplenifolia, A. collina and A. distans belonging to A. millefolium complex of Bulgarian origin, were tested by the modified method of Tan and Berridge. Seven from the investigated fractions showed activity similar or higher than that of indomethacine and might be evaluated as nonsteroidal anti-inflammatory agents.     

Nucleation Catalysis in Metastable Liquids: Inborn Active Sites

A simple formalism is developed in order to analyze the nucleation activity of inborn “week” or “strong” active sites in metastable liquids which can play in nucleation kinetics a role, similar to this of heterogeneous nucleation cores. As examples are examined the influence of Bernal holes and fluctuatively formed Frenkel voids on bubble nucleation, of athermal supercritical nuclei and heterophase fluctuations, frozen‐in in the thermal prehistory of the system on any process of phase formation, and of structural defects, due to change of composition or created in redox processes on crystallization. The analysis is performed in analogy with the known treatment of the influence of heterogeneous foreign cores on nucleation kinetics. Different changes of the metastable liquid are investigated, considering both isobaric thermal quenches and change of pressure at isothermal conditions. The effect of inborn active sites on both steady nucleation rate Iss and on nucleation time lag τ^# is investigated. In this way the whole kinetics of nucleation is constructed using the known approximative solutions of the more general, transient theory of nucleation.