High performance liquid chromatography electrospray ionization tandem mass spectrometry (HPLC-ESI-MS-MS) for the quantification of L-kynurenine and indole-3-acetic acid in grape must by isotope dilution assay

Isotope dilution assay was used for the qualitative and quantitative analysis of L-kynurenine and indole-3-acetic acid in grape must. After solid phase extraction, highest selectivity and sensitivity was achieved by high performance liquid chromatography-electrospray ionization tandem mass spectrometry (HPLC-ESI-MS-MS) using selected reaction monitoring (SRM). In the 24 samples under study, the amounts of L-kynurenine and indole-3-acetic acid ranged from 0 to 94 mu g.l-1 and from 20 to 380 mu g.l-1, respectively. These compounds are considered as potential precursors of 2-aminoacetophenone, causing the ''untypical aging off-flavour'' in Vitis vinifera white wines

Children of Immigrants Longitudinal Survey in Four European Countries (CILS4EU) - Reduced version. Reduced data file for download and off-site use

The study is a panel survey of adolescents designed to study the complex causal mechanism of structural, social, and cultural integration of adolescents with migration background. The data of three waves are currently available. The data set of the first wave includes surveys of students and parents. It enables studying processes of intergenerational transmission and integration. The survey covers topics of (1) cognitive-cultural integration), (2) structural integration, (3) social integration, (4) emotional-cultural integration, and (5) health and wellbeing. In addition there is (6) detailed information about migration experience and demographics. Furthermore, the cognitive-cultural integration on the basis of (1) language proficiency tests (measuring linguistic skills) and (2) a cognitive skills test (measurement of intelligence) was measured. In addition, two aspects of social integration were measured: (1) social integration outside the class context by means of egocentric networks and (2) social integration within the class context by means of a sociometric questionnaire. The data set of the second wave includes re-interviews with students from the first wave. In addition, in the Netherlands students were interviewed who were not part of the first sample (newcomers). These students were integrated in the school classes between the survey waves. The main questionnaire and the social integration within the class context (sociometric questionnaire) were measured repeatedly. The data set of the third wave includes re-interviews with students from the first wave or the second wave. Additionally, 10 students are included who were part of the class list of the first wave, and therefore form part of the first wave’s target population, but were absent at the days of the school surveys in wave 1 and wave 2. The main questionnaire was measured repeatedly. In addition, two aspects of social integration were measured: (1) social integration outside the class context by means of egocentric networks and (2) social integration within the class context by means of a sociometric questionnaire (only in NL). The survey instrument includes country-specific variations. The questionnaire also varies between various modules. For more information, see the study documentation

Children of Immigrants Longitudinal Survey in Four European Countries (CILS4EU) - Full version. Data file for on-site use

The study currently consists of two waves of a panel survey of adolescents designed to study the complex causal mechanism of structural, social, and cultural integration of populations with experience. The data include surveys of students, parents, and teachers. It enables studying processes of intergenerational transmission and integration. The survey covers topics of (1) cognitive-cultural integration (including language proficiency tests), (2) structural integration, (3) social integration, and (4) emotional-cultural integration. In addition there are detailed informations about migration experience and demographics. Cognitive-cultural Integration: Language (objective measures of proficiency in the host country’s language, self-assessed knowledge of L1, self-assessed knowledge of L2, language use, language spoken at home); measurement of cognitive skills; leisure time activities (memberships, leisure time activities); number of books at home. Structural Integration: School performance (self-assessment, grades, setting system, school type, repeating classes, private lessons); attitudes towards school (favourite subjects, educational aspirations, self-efficacy, anti-school norms, efforts in school, value of education, status maintenance motive, teacher support, satisfaction with school, success probabilities, perceived association between educational and occupational success, expected discrimination, financial restrictions, educational costs); economic situation (side job, pocket money, possessions, expected development of own economic situation); deviant behaviour and delinquency (school-related problem behaviour, delinquent behaviour). Social Integration: Sociometric information within classrooms; strong ties (ethnic background of friends); contact person in case of problems; person one is having trouble with; weak ties (in school, neighbourhood, clubs/associations); discrimination (victimisation in school, perceived discrimination); attitudes towards other ethnic groups; romantic relationships (characteristics of partner and relationship, expectations about the future of the relationship), family relations (parental support, parent-child contact, family cohesion, parental expectations, family conflict, embeddedness/influence of parents). Emotional-cultural Integration: Identity (with respect to host, respectively sending country, importance of ethnic identity); attitudes towards integration; religion (religious affiliation, importance of religion, religious practices); attitudes and norms (gender roles, violence legitimizing norms of masculinity, tolerance). Health and well-being: Personality and psychological well-being (life satisfaction, self-esteem, behavioural problems, self-control); health (general health status, health problems, sleeping behaviour, weight, height, health related behaviour, future expectations about health). Demography and migration history: Gender; age; living situation and household composition (household members, household situation, neighbourhood); social background (parents´ education, parents´ employment status, parents´ occupation), migration history (child´s, parents´, and grandparents´ country of birth, age of migration, home-country visits, return migration)

Solid-phase polarization matrixes for dynamic nuclear polarization from homogeneously distributed radicals in mesostructured hybrid silica materials.

International audienceMesoporous hybrid silica-organic materials containing homogeneously distributed stable mono- or dinitroxide radicals covalently bound to the silica surface were developed as polarization matrixes for solid-state dynamic nuclear polarization (DNP) NMR experiments. For TEMPO-containing materials impregnated with water or 1,1,2,2-tetrachloroethane, enhancement factors of up to 36 were obtained at ∼100 K and 9.4 T without the need for a glass-forming additive. We show that the homogeneous radical distribution and the subtle balance between the concentration of radical in the material and the fraction of radicals at a sufficient inter-radical distance to promote the cross-effect are the main determinants for the DNP enhancements we obtain. The material, as well as an analogue containing the poorly soluble biradical bTUrea, is used as a polarizing matrix for DNP NMR experiments of solutions containing alanine and pyruvic acid. The analyte is separated from the polarization matrix by simple filtration