Exploring the Impact of Knowledge and Social Environment on Influenza Prevention and Transmission in Midwestern United States High School Students

We used data from a convenience sample of 410 Midwestern United States students from six secondary schools to develop parsimonious models for explaining and predicting precautions and illness related to influenza. Scores for knowledge and perceptions were obtained using two-parameter Item Response Theory (IRT) models. Relationships between outcome variables and predictors were verified using Pearson and Spearman correlations, and nested [student within school] fixed effects multinomial logistic regression models were specified from these using Akaike’s Information Criterion (AIC). Neural network models were then formulated as classifiers using 10-fold cross validation to predict precautions and illness. Perceived barriers against taking precautions lowered compliance with the CDC recommended preventative practices of vaccination, hand washing quality, and respiratory etiquette. Perceived complications from influenza illness improved social distancing. Knowledge of the influenza illness was a significant predictor for hand washing frequency and respiratory etiquette. Ethnicity and gender had varying effects on precautions and illness severity, as did school-level effects: enrollment size, proficiency on the state’s biology end-of-course examination, and use of free or reduced lunch. Neural networks were able to predict illness, hand hygiene, and respiratory etiquette with moderate success. Models presented may prove useful for future development of strategies aimed at mitigation of influenza in high school youths. As more data becomes available, health professionals and educators will have the opportunity to test and refine these models

Systemic TLR2 agonist exposure regulates hematopoietic stem cells via cell-autonomous and cell-non-autonomous mechanisms

Toll-like receptor 2 (TLR2) is a member of the TLR family of receptors that play a central role in innate immunity. In addition to regulating effector immune cells, where it recognizes a wide variety of pathogen-associated and nonpathogen-associated endogenous ligands, TLR2 is expressed in hematopoietic stem cells (HSCs). Its role in HSCs, however, is not well understood. Furthermore, augmented TLR2 signaling is associated with myelodysplastic syndrome, an HSC disorder characterized by ineffective hematopoiesis and a high risk of transformation to leukemia, suggesting that aberrant signaling through this receptor may have clinically significant effects on HSCs. Herein, we show that systemic exposure of mice to a TLR2 agonist leads to an expansion of bone marrow and spleen phenotypic HSCs and progenitors, but a loss of HSC self-renewal capacity. Treatment of chimeric animals shows that these effects are largely cell non-autonomous, with a minor contribution from cell-autonomous TLR2 signaling, and are in part mediated by granulocyte colony-stimulating factor and tumor necrosis factor-α. Together, these data suggest that TLR2 ligand exposure influences HSC cycling and function via unique mechanisms from TLR4, and support an important role for TLR2 in the regulation of HSCs

Prospectus, April 15, 1991

https://spark.parkland.edu/prospectus_1991/1006/thumbnail.jp

Prospectus, July 1, 1991

https://spark.parkland.edu/prospectus_1991/1009/thumbnail.jp

Prospectus, February 11, 1991

https://spark.parkland.edu/prospectus_1991/1002/thumbnail.jp

Prospectus, April 29, 1991

https://spark.parkland.edu/prospectus_1991/1007/thumbnail.jp

Multiwavelength Studies of Young OB Associations

We discuss how contemporary multiwavelength observations of young OB-dominated clusters address long-standing astrophysical questions: Do clusters form rapidly or slowly with an age spread? When do clusters expand and disperse to constitute the field star population? Do rich clusters form by amalgamation of smaller subclusters? What is the pattern and duration of cluster formation in massive star forming regions (MSFRs)? Past observational difficulties in obtaining good stellar censuses of MSFRs have been alleviated in recent studies that combine X-ray and infrared surveys to obtain rich, though still incomplete, censuses of young stars in MSFRs. We describe here one of these efforts, the MYStIX project, that produced a catalog of 31,784 probable members of 20 MSFRs. We find that age spread within clusters are real in the sense that the stars in the core formed after the cluster halo. Cluster expansion is seen in the ensemble of (sub)clusters, and older dispersing populations are found across MSFRs. Direct evidence for subcluster merging is still unconvincing. Long-lived, asynchronous star formation is pervasive across MSFRs.Comment: 22 pages, 9 figures. To appear in "The Origin of Stellar Clusters", edited by Steven Stahler, Springer, 2017, in pres

Comparative systems biology across an evolutionary gradient within the Shewanella genus

Author Posting. © The Authors, 2009. This is the author's version of the work. It is posted here by permission of National Academy of Sciences for personal use, not for redistribution. The definitive version was published in Proceedings of the National Academy of Sciences 106 (2009): 15909-15914, doi:10.1073/pnas.0902000106.To what extent genotypic differences translate to phenotypic variation remains a poorly understood issue of paramount importance for several cornerstone concepts of microbiology including the species definition. Here, we take advantage of the completed genomic sequences, expressed proteomic profiles, and physiological studies of ten closely related Shewanella strains and species to provide quantitative insights into this issue. Our analyses revealed that, despite extensive horizontal gene transfer within these genomes, the genotypic and phenotypic similarities among the organisms were generally predictable from their evolutionary relatedness. The power of the predictions depended on the degree of ecological specialization of the organisms evaluated. Using the gradient of evolutionary relatedness formed by these genomes, we were able to partly isolate the effect of ecology from that of evolutionary divergence and rank the different cellular functions in terms of their rates of evolution. Our ranking also revealed that whole-cell protein expression differences among these organisms when grown under identical conditions were relatively larger than differences at the genome level, suggesting that similarity in gene regulation and expression should constitute another important parameter for (new) species description. Collectively, our results provide important new information towards beginning a systems-level understanding of bacterial species and genera.The authors have been supported by the DOE through the Shewanella Federation consortium and the Proteomics Application project. The MSU work relevant to speciation was also supported by NSF (DEB 0516252)

Population changes in Leishmania chagasi promastigote developmental stages due to serial passage

Leishmania chagasi causes visceral leishmaniasis, a potentially fatal disease of humans. Within the sand fly vector, L. chagasi replicates as promastigotes which undergo complex changes in morphology as they progress from early stage procyclic promastigotes, to intermediate stage leptomonad and nectomonad promastigotes, and ultimately to terminal stage metacyclic promastigotes that are highly infective to vertebrates. This developmental progression is largely recapitulated in vitro using axenic promastigote cultures that have been passaged only a few times. Within a single passage (which takes about a week), axenic cultures progress from logarithmic to stationary growth phases; parasites within those growth phases progress from stages that do not have metacyclic cell properties to ones that do. Interestingly, repeated serial passage of promastigote cultures will result in cell populations that exhibit perturbations in developmental progression, in expression levels of surface macromolecules (major surface protease, MSP, and promastigote surface antigen, PSA), and in virulence properties, including resistance to serum lysis. Experiments were performed to determine whether there exists a direct relationship between promastigote developmental form and perturbations associated with repeated serial passage. Passage 2 to passage 4 L. chagasi cultures at stationary growth phase were predominately (\u3e85%) comprised of metacyclic promastigotes and exhibited high resistance to serum lysis and high levels of MSP and PSA. Serial passaging 8, or more, times resulted in a stationary phase population that was largely (\u3e85%) comprised of nectomonad promastigotes, almost completely devoid (\u3c2%) of metacyclic promastigotes, and that exhibited low resistance to serum lysis and low levels of MSP and PSA. The study suggests that the loss of particular cell properties seen in cells from serially passaged cultures is principally due to a dramatic reduction in the proportion of metacyclic promastigotes. Additionally, the study suggests that serially passaged cultures may be a highly enriched source of nectomonad-stage promastigotes, a stage that has largely been characterized only in mixtures containing other promastigote forms