Triplet-state photoexcitation dipole-jump relaxation method to observe adsorption/desorption kinetics at a reversed-phase silica/solution interface

Electronic excitation of a probe chromophore can lead to a change in dipole moment that influences its activity or solubility in solution and changes its relative affinity for partitioning between two phases. Photoexcitation of a probe molecule can, therefore, perturb a sorption equilibrium, and the relaxation kinetics of the probe to the new equilibrium conditions can be monitored in a time-resolved luminescence experiment. The adsorption/desorption kinetics of rose bengal, distributed between a C-18 derivatized porous-silica surface and a liquid mobile-phase solution, were investigated. These kinetics were determined by observing their effect on the phosphorescence decay of the triplet state of rose bengal and its quenching by ferricyanide. The methanol/water solvent compositions were varied to alter the fraction of adsorbed rose bengal. The adsorption rate constant for the triplet state was determined from the dependence of the phosphorescence relaxation rate on dye concentration in solution. The results indicate that the adsorption kinetics are diffusion controlled and that the relaxation is influenced by efficient triplet-energy transfer between excited- and ground-state rose bengal at the C-18 silica/solution interface.     

The SARS Crisis: Was Anybody Responsible?

As scholars in fields such as media studies, crisis studies and public policy studies have argued, there exists a fundamental link between crises and the media. Once an event has been interpreted as a crisis, questions of accountability inevitably appear on the media agenda, and the struggle to attribute blame and responsibility to a specific entity or entities—the blame game—thus becomes an inexorable part of the crisis process. Focusing on three liberal Western newspapers with an international, primarily Western elite readership and a reputation for in‐depth analysis of global events, The Economist, the Financial Times and the International Herald Tribune, this article employs Iyengar's and Valkenburg's notions of responsibility frames to examine whether initial coverage of the 2003 SARS crisis in these accounts held any particular entity accountable for the crisis, looks at three key themes used to communicate to the reader a particular way of thinking about responsibility for SARS and examines some of the consequences of the kind of responsibility frame constructed around the SARS crisis in these accounts. As our findings show, there is an entity that the early news accounts studied consistently held responsible for the 2003 SARS crisis, the Chinese system, and the corresponding responsibility frame at operation in these accounts is thematic rather than episodic in nature, since it consistently places the SARS crisis within a broader context (a product of “China” itself and/or of societal‐governmental forces in China) rather than in relation to a specific episode or as the result of the particular actions of individuals. The SARS crisis narrative therefore presented in these accounts tells the story of an anachronistic Chinese system faced with a contemporary health threat that, by its very nature, it is incapable of assessing accurately or managing responsibly. By way of conclusion, we argue that, while the use of such a thematic frame to explain China's role in the 2003 SARS crisis may be accurate in certain respects, this frame falls short in other respects and proves particularly inadequate to the challenge of capturing the economic complexities of China's role during the crisis.     

Relation of emotion-related regulation to children's social competence: A longitudinal study.

The differential relations of children's emotion-related regulation (i.e., effortful control and impulsivity) to their personality resiliency, adult-rated popularity, and social competence were examined in children who were 4.5-7.9 years old and who were remeasured 2 years later. Parents and teachers reported on all constructs, and children's attentional persistence was observed. Structural equation modeling was used to test the mediating role of resiliency on the relations between regulation/control and popularity using two-wave longitudinal data. The results provide some evidence of the mediating role of resiliency in the relations between effortful control and popularity, provide some evidence of bidirectional effects, and also buttress the view that emotional regulation should be differentiated into effortful and reactive forms of control. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Comprehending narratives containing flashbacks: Evidence for temporally organized representations.

This study investigated the representations that readers construct for narratives describing a sequence of events. Participants read narratives describing 4 successive events in chronological order (Event 1, Event 2, Event 3, Event 4 [E1, E2, E3, E4] Experiment 1) or in nonchronological order with E1 being mentioned in a flashback (E2, E3, E1, E4; Experiments 2-4). The information about the duration of E2 was manipulated, and the mental accessibility of E1 was tested at the end of a passage. All 4 experiments showed that E1 was less accessible if the text implied that it occurred a relatively long time ago in the described world compared with when it occurred a shorter time ago. This result suggests that readers construct a temporally organized representation even if the text structure does not suggest such an organization. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Multiple routes to solution of single-digit multiplication problems.

Researchers have assumed that adults solve simple arithmetic problems by retrieving answers from a network of stored facts. In 2 studies, undergraduates described their solutions of single-digit multiplication problems. They reported direct retrieval on approximately 80% of trials but also reported rules (e.g., anything times 0 is 0), repeated addition (e.g., 2?×?4?=?4?+?4), number series (e.g., 3?×?5?=?5, 10, 15), and derived facts (e.g., 6?×?7?=?[6?×?6]?+?6). Participants were slower to retrieve problems that were most likely to be solved by nonretrieval procedures and faster to retrieve problems that were usually solved by retrieval. These results indicate that direct-retrieval models are incomplete accounts of adults' performance and support a continuing influence of learning and experience on the mental representation of simple multiplication problems. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Car insurance and the risk of car crash injury

Despite speculation about the role of vehicle insurance in road traffic accidents, there is little research estimating the direction or extent of the risk relationship. Data from the Auckland Car Crash Injury Study (1998–1999) were used to examine the association between driving an uninsured motor vehicle and car crash injury. Cases were all cars involved in crashes in which at least one occupant was hospitalized or killed anywhere in the Auckland region. Controls were 588 drivers of randomly selected cars on Auckland roads. Participants completed a structured interview. Uninsured drivers had significantly greater odds of car crash injury compared to insured drivers after adjustment for age, sex, level of education, and driving exposure (odds ratio 4.77, 95% confidence interval 2.94–7.75). The causal mechanism for insurance and car crash injury is not easily determined. Although we examined the effects of multiple potential confounders in our analysis including socioeconomic status and risk-taking behaviours, both of which have been previously observed to be associated with both insurance status and car crash injury, residual confounding may partly explain this association. The estimated proportion of drivers who are uninsured is between 5 and 15% in developed countries, representing a significant public health problem worthy of further investigation.     

The use of background and ability profiles to predict college student outcomes.

To determine whether profiles of predictor variables provide incremental prediction of college student outcomes, the authors 1st applied an empirical clustering method to profiles based on the scores of 2,771 entering college students on a battery of biographical data and situational judgment measures, along with SAT and American College Test scores and high school grade point average, which resulted in 5 student groups. Performance of the students in these clusters was meaningfully different on a set of external variables, including college grade point average, self-rated performance, class absenteeism, organizational citizenship behavior, intent to quit their university, and satisfaction with college. The 14 variables in the profile were all significantly correlated with 1 or more of the outcome measures; however, nonlinear prediction of these outcomes on the basis of cluster membership did not add incrementally to a linear-regression-based combination of these 14 variables as predictors. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Exosomes in bodily fluids are a highly stable resource of disease biomarkers

Biomarkers are measurable indicators of a biological state. As our understanding of diseases meliorates, it is generally accepted that early diagnosis renders the best chance to cure a disease. In the context of proteomics, the discovery phase of identifying bonafide biomarkers and the ensuing validation phase involving large cohort of patient samples are impeded by the complexity of bodily fluid samples. High abundant proteins found in blood plasma make it difficult for the detection of low abundant proteins that may be potential biomarkers. Extracellular vesicles (EVs) have reignited interest in the field of biomarker discovery. EVs contain a tissue-type signature wherein a rich cargo of proteins and RNA are selectively packaged. In addition, as EVs are membranous structures, the luminal contents are protected from degradation by extracellular proteases and are highly stable in storage conditions. Interestingly, an appealing feature of EV-based biomarker analysis is the significant reduction in the sample complexity compared to whole bodily fluids. With these prescribed attributes, which are the rate-limiting factors of traditional biomarker analysis, there is immense potential for the use of EVs for biomarker detection in clinical settings. This review will discuss the current issues with biomarker analysis and the potential use of EVs as reservoirs of disease biomarkers.     

ION-SELECTIVE POLYMER-SUPPORTED REAGENTS

ABSTRACT

The design and synthesis of polymer-supported reagents that can selectively complex targeted metal ions from multi-component solutions will continue to be an important area of research into the 21^st century. Environmental remediation and sensor technology are only two of a number of areas in which such polymers can be applied. This paper reviews the recent literature with an emphasis on the key ligands that have been immobilized in order to better understand where this research is heading in the near future.     

Ecological predictors of substance use in middle school students.

The current study examined important predictors of substance use during early adolescence. The authors hypothesized that adolescents' relationships with key adults (i.e., teachers and parents) influence their choices to use substances indirectly through links with their decisions regarding peer groups. A total of 461 middle school students from an affluent suburban community completed self-report measures of authoritative parenting, perceived social support from teachers, affiliation with rule-breaking and substance-using peers, and frequency of alcohol, cigarette, and drug use. Results of structural equation modeling supported the hypothesized model. Authoritative parenting and teacher support accounted for 31% of the variance in affiliation with deviant peers which, in turn, accounted for 27% of the variance in adolescent substance use; direct paths from parenting and teacher support to substance use were not indicated. Implications for school psychologists' involvement in substance use prevention and intervention are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)