Search results for "Periodic table"

3,4′,5,5′-Tetramethoxy-2′-methylbiphenyl-4-ol

2019

The asymmetric unit of the title compound, C17H20O5, contains two independent molecules, A and B, with similar geometries [dihedral angles between the phenyl rings = 56.19 (8) and 54.98 (7)°, respectively]. Intramolecular O—H...O hydrogen bonds occur in both molecules. In the crystal, the A molecules form [1\overline{1}0] chains linked by O—H...O hydrogen bonds from the hydroxyl group to one of the methoxy O atoms. The B molecules form O—H...O hydrogen bonds to the hydroxyl O atoms of the A molecules and thus act as fixed spacers between the chains of molecule A. Some weak C—H...O contacts are also present.

INFLUENCE OF NUTRITION AND GENETICS ON PERFORMANCE: A PILOT STUDY IN A GROUP OF GYMNASTS

2017

Purpose. Energy requirements in sports performance are affected by numerous factors: physical characteristics, age, genetic basis, sports discipline. The Food and Nutrition Board recommended nutrition based on age, height, and body weight gain in relation to physical activity. Some genetic factors, such as the PPAR-encoding gene, play a key role in metabolism. The aim of the study was to investigate the effect of specific snacks on performance. Methods. Seventeen girls aged 10–14 years practising artistic gymnastics were enrolled. A carb or protein/carb snack was provided before the training, and a questionnaire was administered at the end. In addition, saliva samples were collected for gen…

Recommendations for photopatch testing by the Photopatch Test Working Group of the German Contact Dermatitis Research Group (DKG).

2018

Melting point, molecular symmetry and aggregation of tetrachlorobenzene isomers: the role of halogen bonding

2018

Tetrachlorobenzenes represent one of the best known, but not yet fully understood, group of isomers of the structure–melting point relationship. The differences in melting temperatures of these structurally related compounds were rationalized in terms of the hierarchy and nature of formed noncovalent interactions, and the molecular aggregation that is influenced by molecular symmetry. The highest melting point is associated with the highly symmetric 1,2,4,5-tetrachlorobenzene isomer. The structures of less symmetrical 1,2,3,4-tetrachlorobenzene and 1,2,3,5-tetrachlorobenzene, determined at 270 and 90 K, show a distinct pattern of halogen bonds, characterized by the different numbers and typ…

Sorption of V and VI group metalloids (As, Sb, Te) on modified peat sorbents

2016

AbstractThe present work investigates arsenic, antimony and tellurium sorption using iron modified peat. The results were obtained using batch tests and the sorption was studied as a function of initial metalloid concentration, pH and sorption time, as well as the presence of competing substances. The obtained results indicate that modification of peat with Fe compounds significantly enhances the sorption capacity of the sorbents used for sorption of arsenic, antimony and tellurium. The optimal pH interval for the sorption of Sb(III) is 6.5–9 and for As(V) and Sb(V) – 3–6, while As(III) and tellurium sorption using Fe-modified peat is favourable in a wider interval of 3–9. The presence of c…

Bedrock and soil geochemistry influence the content of chemical elements in wild edible mushrooms (Morchella group) from South Italy (Sicily)

2019

Chemical elements in the samples of wild edible mushrooms of the <em>Morchella</em> group collected from different unpolluted Sicilian sites was analyzed by the ICP-MS (method) to detect the content of their minerals and determine whether soil geology and geochemistry can influence the chemical composition in fungi. Results showed that the mushroom samples mainly contained a high concentration of K and P and a wide variety of minor and trace elements (V, Mo, Pb, Ce, Cs, Zr), including heavy metals. Statistical analysis showed that the mushrooms differed in their content of minor and trace elements based on the geological/geographic site of origin. Comparison with other studies s…

N,N-Dicyclohexylnitramine

2016

Molecules of the title compound, C12H22N2O2, are composed of an nitramine group substituted by two cyclohexane rings. The cyclohexane rings have chair conformations, with the exocyclic C—N bonds in axial orientations. In the crystal, C—H...O hydrogen bonds connect the molecules intoC(6) [-101] zigzag chains.

Attachment Anxiety and Attachment Avoidance: Members’ Attachment Fit with Their Group and Group Relationships

2017

We compared each individual group member’s attachment fit with the attachment of the other group members. Participants were 201 members of 20 therapy groups who sought treatment because they were overweight or obese. Group members completed the Attachment Style Questionnaire before commencing treatment and the Group Questionnaire at three points during group treatment. Multilevel polynomial regression followed by response surface analysis was used to examine how the attachment anxiety and avoidance of the individual group member and the aggregated attachment anxiety and avoidance of the group members were related to individual group members’ perceptions of the positive bonding, positive wor…

Block copolymers from ionic liquids for the preparation of thin carbonaceous shells

2017

This paper describes the controlled radical polymerization of an ionic-liquid monomer by RAFT polymerization. This allows the control over the molecular weight of ionic liquid blocks in the range of 8000 and 22000 and of the block-copolymer synthesis. In this work we focus on block copolymers with an anchor block. They can be used to control the formation of TiO2 nanoparticles, which are functionalized thereafter with a block of ionic-liquid polymer. Pyrolysis of these polymer functionalized inorganic nanoparticles leads to TiO2 nanoparticles coated with a thin carbonaceous shell. Such materials may, e.g., be interesting as battery materials.

The pentafluorophenyl group as π-acceptor for anions: a case study

2015

Chemical science 6(1), 354-359 (2015). doi:10.1039/C4SC02762K