Trait Loss in Evolution: What Cavefish Have Taught Us about Mechanisms Underlying Eye Regression.

Reduction or complete loss of traits is a common occurrence throughout evolutionary history. In spite of this, numerous questions remain about why and how trait loss has occurred. Cave animals are an excellent system in which these questions can be answered, as multiple traits, including eyes and pigmentation, have been repeatedly reduced or lost across populations of cave species. This review focuses on how the blind Mexican cavefish, Astyanax mexicanus, has been used as a model system for examining the developmental, genetic, and evolutionary mechanisms that underlie eye regression in cave animals. We focus on multiple aspects of how eye regression evolved in A. mexicanus, including the developmental and genetic pathways that contribute to eye regression, the effects of the evolution of eye regression on other traits that have also evolved in A. mexicanus, and the evolutionary forces contributing to eye regression. We also discuss what is known about the repeated evolution of eye regression, both across populations of A. mexicanus cavefish and across cave animals more generally. Finally, we offer perspectives on how cavefish can be used in the future to further elucidate mechanisms underlying trait loss using tools and resources that have recently become available.

PEDOT:PSS Conductivity Enhancement through Addition of the Surfactant Tween 80.

Replacement of indium tin oxide with the intrinsically conducting polymer poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) has been of significant interest in recent years as a result of lower processing and material costs. In addition, the inclusion of additives has been reported to further enhance the conductivity, rheology, and wettability of PEDOT:PSS. In this study, Tween 80 was shown to decrease the sheet resistance of PEDOT:PSS films from approximately 1000 to 76 Ω□-1 at a 2.67 wt% surfactant concentration. Through X-ray diffraction, Raman spectroscopy, and atomic force microscopy, it was shown that the surfactant caused phase separation and structural ordering of the PEDOT and PSS components, leading to this improvement in conductivity. Furthermore, Tween 80 altered the rheological properties and decreased the surface tension of PEDOT:PSS, making coating common commodity polymers, often used as flexible substrates, more viable.

A history of allergies is associated with reduced risk of oral squamous cell carcinoma.

PURPOSE: A history of allergies is associated with a decreased risk of several types of cancers. Potential mechanisms include enhanced immune surveillance against tumor cells early in disease development and/or carcinogenic infectious agents. We tested whether allergies are inversely associated with oral squamous cell carcinoma (OSCC), accounting for factors that may modify the association, such as tumor site, stage, and HPV infection. METHODS: We estimated odds ratios (OR) and 95 % confidence intervals (CI) for the association between allergy history (including different types of allergies) and OSCC, adjusted for potential confounders, among 400 cases and 613 controls. Analyses were also stratified by site, stage, and measures of HPV infection. RESULTS: We observed a weak inverse association between history of any allergy and OSCC (OR = 0.81, 95 % CI 0.61-1.08). This association was present only for allergies to airborne allergens (dust/pollen/mold) (OR = 0.67; 95 % CI 0.48-0.93). The inverse associations with airborne allergies were slightly stronger for oropharyngeal SCC (OR = 0.56; 95 % CI 0.35-0.90) than for oral cavity SCC (OR = 0.71; 95 % CI 0.49-1.05) and present only for later-stage cancers (OR = 0.42; 95 % CI 0.26-0.66) as opposed to earlier-stage cancers (OR = 0.98; 95 % CI 0.66-1.46). Inverse associations were not particularly present or stronger among HPV-16-seropositive individuals or for HPV DNA-positive OSCC. CONCLUSION: There is an inverse association between history of allergies to dust, pollen, or mold and OSCC. Whether the inverse association involves heightened immune surveillance, increased immune response to HPV or other antigen, or other carcinogenic mechanism remains to be determined in more definitive studies.