Background: Black older-teenaged women have disproportionately high rates of sexually transmitted infections (STI) and unintended pregnancy (UTP). Internet-based interventions can be delivered to large groups of people in a relatively inexpensive manner. In this randomized trial, we examine the efficacy of an evidence-based STI/UTP prevention intervention adapted for older teens and for Internet delivery.
View Article and Find Full Text PDFIndustrial emissions, deteriorating or improperly removed lead paint, and the use of lead additives in fuel have left a substantial burden of heavy metals, such as lead, in urban soils. Much of this lead remains near the surface where it has the potential to impact human health. Exposure to lead, especially in children, can have lasting impacts on neurological development and academic achievement.
View Article and Find Full Text PDFThis study examines the implications of a history of personal violence on health and health behaviors. A secondary analysis of cross-sectional data involving adults (n = 214) from a semirural area in southern Louisiana between October 2008 and December 2010 was conducted to ascertain the association between a personal history of violence victimization and indicators of sexual health behaviors and outcomes: communication with sexual partners about HIV status, consistent condom use, and sexually transmitted infection (STI). While violence victimization is widely accepted as a risk factor for high-risk sex behavior, the mechanisms underlying violence victimization's influence on sexual health outcomes remain unclear.
View Article and Find Full Text PDFEarth's mightiest ocean current, the Antarctic Circumpolar Current (ACC), regulates the exchange of heat and carbon between the ocean and the atmosphere, and influences vertical ocean structure, deep-water production and the global distribution of nutrients and chemical tracers. The eastward-flowing ACC occupies a unique circumglobal pathway in the Southern Ocean that was enabled by the tectonic opening of key oceanic gateways during the break-up of Gondwana (for example, by the opening of the Tasmanian Gateway, which connects the Indian and Pacific oceans). Although the ACC is a key component of Earth's present and past climate system, the timing of the appearance of diagnostic features of the ACC (for example, low zonal gradients in water-mass tracer fields) is poorly known and represents a fundamental gap in our understanding of Earth history.
View Article and Find Full Text PDFBiological responses of human skin to UVR including cancer and aging are largely wavelength-dependent, as shown by the action spectra of UVR-induced erythema and nuclear DNA (nDNA) damage. A molecular dosimeter of UVR exposure is therefore required. Although mitochondrial DNA (mtDNA) damage has been shown to be a reliable and sensitive biomarker of UVR exposure in human skin, its wavelength dependency is unknown.
View Article and Find Full Text PDFPaleoproductivity is a critical component in past ocean biogeochemistry, but accurate reconstructions of productivity are often hindered by limited integration of proxies. Here, we integrate geochemical (phosphorus) and micropaleontological proxies at millennial timescales, revealing that the coccolithophore record in the Subantarctic zone of the South Atlantic Ocean is driven largely by variations in marine phosphorus availability. A quantitative micropaleontological and geochemical analysis carried out in sediments retrieved from Ocean Drilling Program Site 1089 (Subantarctic Zone) reveals that most of the export productivity in this region over the last 0.
View Article and Find Full Text PDFSkin cancer incidence is dramatically increasing worldwide, with exposure to ultraviolet radiation (UVR) a predominant factor. The UVA component initiates oxidative stress in human skin, although its exact role in the initiation of skin cancer, particularly malignant melanoma, remains unclear and is controversial because there is evidence for a melanin-dependent mechanism in UVA-linked melanoma studies. Nonpigmented (CHL-1, A375), moderately pigmented (FM55, SKmel23), and highly pigmented (FM94, hyperpigmented FM55) human melanoma cell lines have been used to investigate UVA-induced production of reactive oxygen species using FACS analysis, at both the cellular (dihydrorhodamine-123) and the mitochondrial (MitoSOX) level, where most cellular stress is generated.
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