Crystal structure of 1-benzoyl-2,7-dimethoxy-8-(3,5-dimethylbenzoyl) naphthalene: Head-to-head fashioned molecular motif for accumulating weak non-classical hydrogen bonds

Title compound, 1-benzoyl-2,7-dimethoxy-8-(3,5-dimethylbenzoyl)naphthalene, an unsymmetrically substituted aromatic diketone compound having non-coplanarly accumulated aromatic rings structure, has been synthesized and its crystal structure has been determined by X-ray crystallography. The asymmetric unit of title compound contains two independent conformers. For each conformer, the two aroyl groups are non-coplanarly situated against the naphthalene ring plane and oriented in an opposite direction. The 3,5-dimethylbenzoyl group leans more than the non-substituted benzoyl group on the other peri-position of the naphthalene ring. The characteristics in the single molecular crystal structure of this unsymmetrical compound show unique relationship with two symmetrically substituted homologues, namely 1,8-dibenzoyl-2,7-dimethoxynaphthalene and 2,7-dimethoxy-1,8-bis(3,5-dimethylbenzoyl) naphthalene. Dihedral angles between 3,5-dimethylbenzene ring and naphthalene ring of 2,7-dimethoxy-1,8-bis(3,5-dimethylbenzoyl)naphthalene are larger than those between benzene ring and naphthalene ring of 1,8-dibenzoyl-2,7-dimethoxynaphthalene. Dihedral angle between 3,5-dimethylbenzoyl group and naphthalene ring in title compound is close to those of symmetrical homologue having two 3,5-dimethylbenzoyl groups. In the similar manner, dihedral angle between non-substituted benzoyl group and naphthalene ring in title compound is also close to those of symmetrical homologue bearing two non-substituted benzoyl groups. On the other hand, the crystal packing of title compound has rather similar feature with 2,7-dimethoxy-1,8-bis(3,5-dimethylbenzoyl)naphthalene. Two compounds have common crystalline molecular structural motif of head-to-head fashioned intermolecular interaction of 3,5-dimethylbenzoyl moieties. It is interpreted that the interactions between (sp3)C–H and π orbital preferentially govern the molecular packing motif. Molecular structure feature of title compound and the symmetrically 3,5-dimethylbenzoylated homologue strongly manifests that accumulation of weak non-classical hydrogen bonds play a crucial role in determination of the crystal packing rather than sole function of stronger non-classical hydrogen bond and π…π stacking

Twenty four year time trends in fats and cholesterol intake by adolescents. Warsaw Adolescents Study

The objective of this study was to determine time trends (1982–2006) in total fat intake and changes in fatty acid structure intake in adolescents from Warsaw in view of increasing prevalence of obesity. Data come from four successive surveys randomly selected samples of adolescents (aged 11–15 years old), from Warsaw region. In total 9747 pupils have been examined, with response rate varying from 55% to 87% depending on year. Surveys were done always in the spring season of the year. Food intake was assessed by using 24 hours recall method of consumption by the pupils all products, including enriched, dishes and beverages as well as diet supplements, in the last 24 hours preceding the examination. The content of energy and nutrients was calculated by means of own computer softwares (DIET 2 and 4), taking into account successive revisions of the tables of food composition and nutritional values, as well as current Polish DRI. A significant decreasing trend was found in intake of total fat, of saturated fatty acids (SFA) and cholesterol. The percentage of energy from total fat, also decreased both in boys (to 35,1%) and girls (to 33,7%), what failed to reach the desired level below 30% of energy from fat which is recommended. Also significant decrease of SFA consumption was not satisfactory enough to approach the values <10% of energy recommended as was from 13% to 15%. Decreasing trends in fat intake was not in accordance with the trend in obesity prevalence in the adolescents as average BMI is going up. To stabilize the health-oriented changes especially in the diets of adolescents, further activity is desired from professionals working with prevention of adolescents obesity

Twenty four year time trends in fats and cholesterol intake by adolescents. Warsaw Adolescents Study

The objective of this study was to determine time trends (1982–2006) in total fat intake and changes in fatty acid structure intake in adolescents from Warsaw in view of increasing prevalence of obesity. Data come from four successive surveys randomly selected samples of adolescents (aged 11–15 years old), from Warsaw region. In total 9747 pupils have been examined, with response rate varying from 55% to 87% depending on year. Surveys were done always in the spring season of the year. Food intake was assessed by using 24 hours recall method of consumption by the pupils all products, including enriched, dishes and beverages as well as diet supplements, in the last 24 hours preceding the examination. The content of energy and nutrients was calculated by means of own computer softwares (DIET 2 and 4), taking into account successive revisions of the tables of food composition and nutritional values, as well as current Polish DRI. A significant decreasing trend was found in intake of total fat, of saturated fatty acids (SFA) and cholesterol. The percentage of energy from total fat, also decreased both in boys (to 35,1%) and girls (to 33,7%), what failed to reach the desired level below 30% of energy from fat which is recommended. Also significant decrease of SFA consumption was not satisfactory enough to approach the values <10% of energy recommended as was from 13% to 15%. Decreasing trends in fat intake was not in accordance with the trend in obesity prevalence in the adolescents as average BMI is going up. To stabilize the health-oriented changes especially in the diets of adolescents, further activity is desired from professionals working with prevention of adolescents obesity

A modular design approach to polymer-coated ZnO nanocrystals

Summary: Hybrid materials based on inorganic nanocrystals with organic polymers feature peculiar and fascinating properties and various applications. However, there is still a need for simple synthesis procedures that provide precise control over the polymer/nanocrystal microstructure of these materials. Herein, a novel organometallic approach to polymer-coated ZnO nanocrystals was developed. The presented method merges the initial ring-opening polymerization of ϵ-caprolactone mediated by an organozinc alkoxide initiator and an air-promoted transformation of the resulting macromolecular organozinc species. This one-pot procedure results in quantum-sized ZnO crystals with a core diameter of ca 3 nm coated by poly(ϵ-caprolactone) covalently bonded to the surface. Overall, the ability to create well-defined hybrid composites should provide a unique ability to access various nanosystems