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Heterostructures made from van der Waals materials provide a template to investigate proximity effects at atomically sharp heterointerfaces. In particular, near-field charge and energy transfer in heterostructures made from semiconducting transition metal dichalcogenides (TMD) have attracted interest to design model 2D "donor-acceptor" systems and new optoelectronic components. Here, using of Raman scattering and photoluminescence spectroscopies, we report a comprehensive characterization of a molybedenum diselenide (MoSe$_2$) monolayer deposited onto hexagonal boron nitride (hBN) and capped by mono- and bilayer graphene. Along with the atomically flat hBN susbstrate, a single graphene epilayer is sufficient to passivate the MoSe$_2$ layer and provides a homogenous environment without the need for an extra capping layer. As a result, we do not observe photo-induced doping in our heterostructure and the MoSe$_2$ excitonic linewidth gets as narrow as 1.6~meV, hence approaching the homogeneous limit. The semi-metallic graphene layer neutralizes the 2D semiconductor and enables picosecond non-radiative energy transfer that quenches radiative recombination from long-lived states. Hence, emission from the neutral band edge exciton largely dominates the photoluminescence spectrum of the MoSe$_2$/graphene heterostructure. Since this exciton has a picosecond radiative lifetime at low temperature, comparable with the energy transfer time, its low-temperature photoluminescence is only quenched by a factor of $3.3 \pm 1$ and $4.4 \pm 1$ in the presence of mono- and bilayer graphene, respectively. Finally, while our bare MoSe$_2$ on hBN exhibits negligible valley polarization at low temperature and under near-resonant excitation, we show that interfacing MoSe$_2$ with graphene yields a single-line emitter with degrees of valley polarization and coherence up to $\sim 15\,\%$., version 3, 5 figures

Background Little is known about stroke awareness in Latinos with low literacy and living in regions with high stroke rates. Methods We surveyed a convenience sample of 60 adult Latinos living in Charleston South Carolina to examine recognition of 4 common warning signs of stroke and appropriate first action to call 9-1-1. Results Forty-six percent of the participants recognized sudden facial, arm, or leg weakness; 39% recognized sudden vision loss; 43% recognized sudden trouble walking; 45% recognized sudden headache; 17% recognized all four warning signs. Twenty-seven percent of the participants incorrectly identified chest pain as a warning sign of stroke. Participants at the lowest literacy levels recognized three of the four warning signs more frequently than the participants at higher literacy levels. Discussion Overall, awareness of stroke warning signs was considerably low in this high-risk population. The relationship between low-literacy and stroke awareness was unclear in this sample.

Limited English proficiency (LEP) and other sociodemographic factors are believed to impact health knowledge, healthcare access and overall health status. However, the role LEP plays in the overall health awareness and receipt of healthcare services is not adequately understood.We surveyed 60 LEP Hispanic/Latino adults to determine their awareness of common health conditions in Hispanic/Latino communities and describe their experiences accessing and utilizing health services in the Charleston, SC area.Awareness of Common Health Conditions: The majority of participants identified alcoholism as an important health condition among Hispanic/Latino adults. Other common health conditions reported included drug use, diabetes, HIV/AIDS, and cancer. Access to Health Services: All of the participants reported problems obtaining needed health services in the past. Problems reported were associated with costs, insurance and lack of Spanish-speaking service providers. Utilization of Health Services: More than 70% of the participants went to the doctor when they were sick, but 50% had never had a physical examination.The LEP Hispanic/Latino adults in this survey were generally aware of major health-related conditions common among Hispanics/Latinos. The presence of LEP did not significantly impact awareness of common health conditions in Hispanic/Latino communities. Healthcare access and utilization were influenced by a number factors associated with the local healthcare system.