902 resultados para suspension cultures


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Within-subject standardization (ipsatization) has been advocated as a possible means to control for culture-specific responding (e.g., Fisher, 2004). However, the consequences of different kinds of ipsatization procedures for the interpretation of mean differences remain unclear. The current study compared several ipsatization procedures with ANCOVA-style procedures using response style indicators for the construct of family orientation with data from 14 cultures and two generations from the Value-of-Children-(VOC)-Study (4135 dyads). Results showed that within-subject centering/standardizing across all Likert-scale items of the comprehensive VOC-questionnaire removed most of the original cross-cultural variation in family orientation and lead to a non-interpretable pattern of means in both generations. Within-subject centering/standardizing using a subset of 19 unrelated items lead to a decrease to about half of the original effect size and produced a theoretically meaningful pattern of means. A similar effect size and similar mean differences were obtained when using a measure of acquiescent responding based on the same set of items in an ANCOVA-style analysis. Additional models controlling for extremity and modesty performed worse, and combinations did not differ from the acquiescence-only model. The usefulness of different approaches to control for uniform response styles (scalar equivalence not given) in cross- cultural comparisons is discussed.

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How is adolescents’ willingness for intergenerational support affected by parents’ expectations and parenting behavior? Does youths’ willingness for intergenerational support in turn affect parents’ well-being? The current study addresses these questions from a cross-cultural perspective, using data from connected samples of mother-adolescent dyads (N = 4162) from 14 diverse cultural contexts as part of the “Value of Children and Intergenerational Relations Study” (Trommsdorff & Nauck, 2005). The results are based on mixed model analyses (with culture as a random factor). Associations were investigated between family norms (expectations of support by adult children), parenting goals (obedience, independence) and parenting behavior (acceptance, control) reported by mothers and adolescents’ reports on willingness to support (help in household tasks, willingness to tolerate burdens in order to help their parents in case of accident, emotional support given to mothers and fathers). Across cultures, maternal expectations of adult children were positively related to adolescents’ reported household help and their current emotional support to mothers and fathers. Obedience, and control were positively related to the amount of adolescent help in the household, while independence and acceptance were related to a higher willingness to tolerate burdens as well as to higher emotional support given to the mother. Regarding associations between adolescents’ actual and intended intergenerational support with mothers’ life satisfaction, adolescents’ willingness to tolerate burdens was related to a higher maternal life satisfaction while adolescents’ reported household help was not. Adolescents’ current emotional support to fathers (but not to mothers) was also related to higher maternal life satisfaction. While most of the effects were stable across cultures (no significant random slope variance across cultural groups), some effects did significantly vary across cultures. Traditional-vs.-secular values as culture-level characteristics will be discussed as explanation for these culture-specific relations among mothers’ expectations, adolescents’ intergenerational support, and mothers’ life satisfaction.

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OBJECTIVES Osteoclasts rapidly form on the surface of bone chips at augmentation sites. The underlying molecular mechanism, however, is unclear. Soluble factors released from bone chips in vitro have a robust impact on mesenchymal cell differentiation. Whether these soluble factors change the differentiation of hematopoietic cells into osteoclasts remains unknown. METHODS Osteoclastogenesis, the formation of tartrate-resistant acid phosphatase-positive multinucleated cells, was studied with murine bone marrow cultures exposed to RANKL and M-CSF, and conditioned medium from fresh (BCM) and demineralized bone matrix (DCM). Histochemical staining, gene and protein expression, as well as viability assays were performed. RESULTS This study shows that BCM had no impact on osteoclastogenesis. However, when BCM was heated to 85°C (BCMh), the number of tartrate-resistant acid phosphatase-positive multinucleated cells that developed in the presence of RANKL and M-CSF approximately doubled. In line with the histochemical observations, there was a trend that BCMh increased expression of osteoclast marker genes, in particular the transcription factor c-fos. The expression of c-fos was significantly reduced by the TGF-β receptor I antagonist SB431542. DCM significantly stimulated osteoclastogenesis, independent of thermal processing. CONCLUSIONS These data demonstrate that activated BCM by heat and DBM are able to stimulate osteoclastogenesis in vitro. These in vitro results support the notion that the resorption of autografts may be supported by as yet less defined paracrine mechanisms.

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When proposing primary control (changing the world to fit self)/secondary control (changing self to fit the world) theory, Weisz et al. (1984) argued for the importance of the “serenity to accept the things I cannot change, the courage to change the things I can” (p. 967), and the wisdom to choose the right control strategy that fits the context. Although the dual processes of control theory generated hundreds of empirical studies, most of them focused on the dichotomy of PC and SC, with none of these tapped into the critical concept: individuals’ ability to know when to use what. This project addressed this issue by using scenario questions to study the impact of situationally adaptive control strategies on youth well-being. To understand the antecedents of youths’ preference for PC or SC, we also connected PCSC theory with Dweck’s implicit theory about the changeability of the world. We hypothesized that youths’ belief about the world’s changeability impacts how difficult it was for them to choose situationally adaptive control orientation, which then impacts their well-being. This study included adolescents and emerging adults between the ages of 18 and 28 years (Mean = 20.87 years) from the US (n = 98), China (n = 100), and Switzerland (n = 103). Participants answered a questionnaire including a measure of implicit theories about the fixedness of the external world, a scenario-based measure of control orientation, and several measures of well-being. Preliminary analyses of the scenario-based control orientation measures showed striking cross-cultural similarity of preferred control responses: while for three of the six scenarios primary control was the predominately chosen control response in all cultures, for the other three scenarios secondary control was the predominately chosen response. This suggested that youths across cultures are aware that some situations call for primary control, while others demand secondary control. We considered the control strategy winning the majority of the votes to be the strategy that is situationally adaptive. The results of a multi-group structural equation mediation model with the extent of belief in a fixed world as independent variable, the difficulties of carrying out the respective adaptive versus non-adaptive control responses as two mediating variables and the latent well-being variable as dependent variable showed a cross-culturally similar pattern of effects: a belief in a fixed world was significantly related to higher difficulties in carrying out the normative as well as the non-normative control response, but only the difficulty of carrying out the normative control response (be it primary control in situations where primary control is normative or secondary control in situations where secondary control is normative) was significantly related to a lower reported well-being (while the difficulty of carrying out the non-normative response was unrelated to well-being). While previous research focused on cross-cultural differences on the choice of PC or SC, this study shed light on the universal necessity of applying the right kind of control to fit the situation.

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In this paper we report on our study of the changes in biomass, lipid composition, and fermentation end products, as well as in the ATP level and synthesis rate in cultivated potato (Solanum tuberosum) cells submitted to anoxia stress. During the first phase of about 12 h, cells coped with the reduced energy supply brought about by fermentation and their membrane lipids remained intact. The second phase (12–24 h), during which the energy supply dropped down to 1% to 2% of its maximal theoretical normoxic value, was characterized by an extensive hydrolysis of membrane lipids to free fatty acids. This autolytic process was ascribed to the activation of a lipolytic acyl hydrolase. Cells were also treated under normoxia with inhibitors known to interfere with energy metabolism. Carbonyl-cyanide-4-trifluoromethoxyphenylhydrazone did not induce lipid hydrolysis, which was also the case when sodium azide or salicylhydroxamic acid were fed separately. However, the simultaneous use of sodium azide plus salicylhydroxamic acid or 2-deoxy-D-glucose plus iodoacetate with normoxic cells promoted a lipid hydrolysis pattern similar to that seen in anoxic cells. Therefore, a threshold exists in the rate of ATP synthesis (approximately 10 μmol g−1 fresh weight h−1), below which the integrity of the membranes in anoxic potato cells cannot be preserved.

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The cause of infection of about a third of all travelers' diarrhea patients studied is not identified. Stools of these diarrhea patients tested for known enteric pathogens are shown to be negative, and identified as pathogen negative stools. We proposed that the third of these diarrhea patients might not only include at present unknown pathogens, but also known pathogens that go undetected. Conventionally, a probability sample of five E. coli colonies are used detect enterotoxigenic E. coli (ETEC) and other diarrhea-producing E. coli from stool cultures. We compared this conventional method of using five E. coli colonies, to the use of up to twenty E. coli colonies. Testing for up to fifteen E. coli colonies detected about twice as many ETEC when compared to the detection of ETEC, testing for five E. coli colonies. When the number of E. coli colonies tested was increased from 5 to 15, the detection of ETEC increased from 19.0% to 38.8%. The sensitivity of the assay with 5 E. coli colonies was statistically significantly different to the sensitivity of the assay with 10 E. coli colonies, suggesting that for the detection of ETEC at least 10 colonies of E. coli should be tested.^