Gibbs entropy and irreversible thermodynamics

Recently a number of approaches has been developed to connect the microscopic dynamics of particle systems to the macroscopic properties of systems in nonequilibrium stationary states, via the theory of dynamical systems. This way a direct connection between dynamics and Irreversible Thermodynamics has been claimed to have been found. However, the main quantity used in these studies is a (coarse-grained) Gibbs entropy, which to us does not seem suitable, in its present form, to characterize nonequilibrium states. Various simplified models have also been devised to give explicit examples of how the coarse-grained approach may succeed in giving a full description of the Irreversible Thermodynamics. We analyze some of these models pointing out a number of difficulties which, in our opinion, need to be overcome in order to establish a physically relevant connection between these models and Irreversible Thermodynamics.Comment: 19 pages, 4 eps figures, LaTeX2

The efficiency of CD4 recruitment to ligand-engaged TCR controls the agonist/partial agonist properties of peptide-MHC molecule ligands.

One hypothesis seeking to explain the signaling and biological properties of T cell receptor for antigen (TCR) partial agonists and antagonists is the coreceptor density/kinetic model, which proposes that the pharmacologic behavior of a TCR ligand is largely determined by the relative rates of (a) dissociation ofligand from an engaged TCR and (b) recruitment oflck-linked coreceptors to this ligand-engaged receptor. Using several approaches to prevent or reduce the association of CD4 with occupied TCR, we demonstrate that consistent with this hypothesis, the biological and biochemical consequence of limiting this interaction is to convert typical agonists into partial agonist stimuli. Thus, adding anti-CD4 antibody to T cells recognizing a wild-type peptide-MHC class II ligand leads to disproportionate inhibition of interleukin-2 (IL-2) relative to IL-3 production, the same pattern seen using a TCR partial agonist/antagonist. In addition, T cells exposed to wild-type ligand in the presence of anti-CD4 antibodies show a pattern of TCR signaling resembling that seen using partial agonists, with predominant accumulation of the p21 tyrosine-phosphorylated form of TCR-zeta, reduced tyrosine phosphorylation of CD3epsilon, and no detectable phosphorylation of ZAP-70. Similar results are obtained when the wild-type ligand is presented by mutant class II MHC molecules unable to bind CD4. Likewise, antibody coligation of CD3 and CD4 results in an agonist-like phosphorylation pattern, whereas bivalent engagement of CD3 alone gives a partial agonist-like pattern. Finally, in accord with data showing that partial agonists often induce T cell anergy, CD4 blockade during antigen exposure renders cloned T cells unable to produce IL-2 upon restimulation. These results demonstrate that the biochemical and functional responses to variant TCR ligands with partial agonist properties can be largely reproduced by inhibiting recruitment of CD4 to a TCR binding a wild-type ligand, consistent with the idea that the relative rates of TCR-ligand disengagement and of association of engaged TCR with CD4 may play a key role in determining the pharmacologic properties of peptide-MHC molecule ligands. Beyond this insight into signaling through the TCR, these results have implications for models of thymocyte selection and the use of anti-coreceptor antibodies in vivo for the establishment ofimmunological tolerance

The human salivary microbiome exhibits temporal stability in bacterial diversity

The temporal variability of the human microbiome may be an important factor in determining its relationship with health and disease. In this study, the saliva of 40 participants was collected every 2 months over a one-year period to determine the temporal variability of the human salivary microbiome. Salivary pH and 16S rRNA gene copy number were measured for all participants, with the microbiome of 10 participants assessed through 16S rRNA amplicon sequencing. In February 2013, 16S rRNA gene copy number was significantly (P < 0.001) higher, with individual changes between time points significant (P = 0.003). Salivary pH levels were significantly (P < 0.001) higher in December 2012 than in October 2012 and February 2013, with significant (P < 0.001) individual variations seen throughout. Bacterial α-diversity showed significant differences between participants (P < 0.001), but not sampling periods (P = 0.801), and a significant positive correlation with salivary pH (R(2) = 7.8%; P = 0.019). At the phylum level, significant differences were evident between participants in the Actinobacteria (P < 0.001), Bacteroidetes (P < 0.001), Firmicutes (P = 0.008), Fusobacteria (P < 0.001), Proteobacteria (P < 0.001), Synergistetes (P < 0.001) and Spirochaetes (P = 0.003) phyla. This study charted the temporal variability of the salivary microbiome, suggesting that bacterial diversity is stable, but that 16S rRNA gene copy number may be subject to seasonal flux

Collecting, archiving and processing DNA from wildlife samples using FTA(® )databasing paper

BACKGROUND: Methods involving the analysis of nucleic acids have become widespread in the fields of traditional biology and ecology, however the storage and transport of samples collected in the field to the laboratory in such a manner to allow purification of intact nucleic acids can prove problematical. RESULTS: FTA(® )databasing paper is widely used in human forensic analysis for the storage of biological samples and for purification of nucleic acids. The possible uses of FTA(® )databasing paper in the purification of DNA from samples of wildlife origin were examined, with particular reference to problems expected due to the nature of samples of wildlife origin. The processing of blood and tissue samples, the possibility of excess DNA in blood samples due to nucleated erythrocytes, and the analysis of degraded samples were all examined, as was the question of long term storage of blood samples on FTA(® )paper. Examples of the end use of the purified DNA are given for all protocols and the rationale behind the processing procedures is also explained to allow the end user to adjust the protocols as required. CONCLUSIONS: FTA(® )paper is eminently suitable for collection of, and purification of nucleic acids from, biological samples from a wide range of wildlife species. This technology makes the collection and storage of such samples much simpler

PREDICTORS OF ACADEMIC SUCCESS AMONG AFRICAN AMERICAN COLLEGE STUDENTS

African American students are graduating from high school and enrolling in higher educational institutions at greater rates than in previous years (U.S. Department of Education, 2009). Yet, they have not achieved the same level of academic success as their racial counterparts (American Council on Education, 2010; Ross, 2012). Ultimately, this disparity has resulted in only 17.7% of the African American population 25 years of age and older having at least a Bachelor’s degree (U.S. Department of Commerce, 2012). Many researchers have employed comparative study designs to explore this disparity. Additionally, researchers commonly study academic success through the exploration of intrapsychic or environmental contributing factors. As a result, limited studies examining the confluence of these factors exist in the literature, and the impact of these contributing factors is not clearly understood. This study seeks to explore the predictive factors of academic success among African American students by attending to both intrapsychic and environmental factors without the comparison of African American students to students from other races/ethnicities. Employing Tinto’s longitudinal model of institutional departure (Tinto, 1993) and positive psychological approaches, this study will use multiple foci and strengths to answer the research question: Do racial identity, goal commitment, and institutional climate predict academic success among African American college students? Academic success was measured in this study by academic adjustment, social adjustment, and self-reported grade point average (GPA). Data consisted of 240 African American freshmen from colleges and universities across the nation. Participants completed an online survey that assessed their perceptions regarding racial identity, institutional climate, goal commitment, academic adjustment, social adjustment, and GPA. The results showed that racial identity and institutional climate predicted academic adjustment and social adjustment, but not GPA. Goal commitment predicted academic adjustment, social adjustment, and GPA. When all predictors were combined in the same regression analysis, academic adjustment, social adjustment, and GPA were each predicted and unique significant contributors to the explained variance in those analyses emerged. These findings may help address some of the gaps in the literature regarding academic success among African American students These results can aid in the understanding of the impact of racial identity, institutional climate, and goal commitment among African American college students. Additionally, these results may to the creation of environmental conditions that can facilitate a connection and commitment to higher educational institutions and thus, adaptive academic and psychological outcomes

The effects of expert witness testimony on juror verdict: psychiatry versus psychology

The purpose of this study was to explore the effects of expert witness testimony on juror verdicts. We, further, assessed whether there would be a difference in the relative influence of MDs and PhD expert witnesses. Undergraduate and graduate students served as mock jurors and were presented with an insanity case which either (a) a PhD testified for the defense and a MD testified for the prosecution or (b) an MD testified for the defense and a PhD testified for the prosecution. After analysis of verdicts, an Insanity Defense Attitudes Survey, and specific witness credibility evaluations indicated no bias toward MD\u27s, except for the PhD-defense/MD-prosecution condition. Implications for other case factors that combine to affect jurors\u27 verdicts are discussed