University of Memphis

About: University of Memphis is a education organization based out in Memphis, Tennessee, United States. It is known for research contribution in the topics: Population & Poison control. The organization has 7710 authors who have published 20082 publications receiving 611618 citations. The organization is also known as: U of M.

The evolution and genomic basis of beetle diversity.

Abstract: The order Coleoptera (beetles) is arguably the most speciose group of animals, but the evolutionary history of beetles, including the impacts of plant feeding (herbivory) on beetle diversification, remain poorly understood. We inferred the phylogeny of beetles using 4,818 genes for 146 species, estimated timing and rates of beetle diversification using 89 genes for 521 species representing all major lineages and traced the evolution of beetle genes enabling symbiont-independent digestion of lignocellulose using 154 genomes or transcriptomes. Phylogenomic analyses of these uniquely comprehensive datasets resolved previously controversial beetle relationships, dated the origin of Coleoptera to the Carboniferous, and supported the codiversification of beetles and angiosperms. Moreover, plant cell wall-degrading enzymes (PCWDEs) obtained from bacteria and fungi via horizontal gene transfers may have been key to the Mesozoic diversification of herbivorous beetles—remarkably, both major independent origins of specialized herbivory in beetles coincide with the first appearances of an arsenal of PCWDEs encoded in their genomes. Furthermore, corresponding (Jurassic) diversification rate increases suggest that these novel genes triggered adaptive radiations that resulted in nearly half of all living beetle species. We propose that PCWDEs enabled efficient digestion of plant tissues, including lignocellulose in cell walls, facilitating the evolution of uniquely specialized plant-feeding habits, such as leaf mining and stem and wood boring. Beetle diversity thus appears to have resulted from multiple factors, including low extinction rates over a long evolutionary history, codiversification with angiosperms, and adaptive radiations of specialized herbivorous beetles following convergent horizontal transfers of microbial genes encoding PCWDEs.

Clinical utility of the 3-ounce water swallow test.

Abstract: The 3-ounce water swallow test is frequently used to screen individuals for aspiration risk. Prior research concerning its clinical usefulness, however, is confounded by inadequate statistical power due to small sample sizes and varying methodologies. Importantly, research has been limited to a few select patient populations, thereby limiting the widespread generalizability and applicability of the 3-ounce test. The purpose of this study was to investigate the clinical utility of the 3-ounce water swallow test for determining aspiration status and oral feeding recommendations in a large and heterogeneous patient population. Fiberoptic endoscopic evaluation of swallowing (FEES) was performed in conjunction with the 3-ounce water swallow test on 3000 participants with a wide range of ages and diagnoses. A total of 1151 (38.4%) passed and 1849 (61.6%) failed the 3-ounce water swallow test. Sensitivity of the 3-ounce water swallow test for predicting aspiration status during FEES = 96.5%, specificity = 48.7%, and false positive rate = 51.3%. Sensitivity for identifying individuals who were deemed safe for oral intake based on FEES results = 96.4%, specificity = 46.4%, and false positive rate = 53.6%. Passing the 3-ounce water swallow test appears to be a good predictor of ability to tolerate thin liquids. However, failure often does not indicate inability to tolerate thin liquids, i.e., low specificity and high false-positive rate. Use of the 3-ounce water swallow test alone to make decisions regarding safety of liquid intake results in over-referral and unnecessary restriction of liquid intake for nearly 50% of patients tested. In addition, because 71% of participants who failed the 3-ounce water swallow test were deemed safe for an oral diet, nonsuccess on the 3-ounce water swallow test is not indicative of swallowing failure. The clinical utility of the 3-ounce water swallow test has been extended to include a wide range of medical and surgical diagnostic categories. Importantly, for the first time it has been shown that if the 3-ounce water swallow test is passed, diet recommendations can be made without further objective dysphagia testing.

In the Founder's Shadow: Conflict in the Family Firm:

Abstract: This paper examines the extent to which conflict across generations of family firms is due to the effects of two independent variables—generation and generational shadow. The presence of a generational shadow was indicated by whether either or both of the parents continued to influence the company once the next generation assumed control. Hypotheses predicted nonlinear trends in conflict and interactions between generation and generational shadow. Using data from a national telephone survey of over 1,000 family business owners, the results of an ANOVA test confirmed that the presence of generational shadow, in particular, that of the founder, increases organizational conflict.

Size-dependent cell uptake of protein-coated graphene oxide nanosheets

Abstract: As an emerging applied material, graphene has shown tremendous application potential in many fields, including biomedicine. However, the biological behavior of these nanosheets, especially their interactions with cells, is not well understood. Here, we report our findings about the cell surface adhesion, subcellular locations, and size-dependent uptake mechanisms of protein-coated graphene oxide nanosheets (PCGO). Small nanosheets enter cells mainly through clathrin-mediated endocytosis, and the increase of graphene size enhances phagocytotic uptake of the nanosheets. These findings will facilitate biomedical and toxicologic studies of graphenes and provide fundamental understanding of interactions at the interface of two-dimensional nanostructures and biological systems.