Simultaneous Two- and Three-Photon Deep Imaging of Autofluorescence in Bacterial Communities.

The intrinsic fluorescence of bacterial samples has a proven potential for label-free bacterial characterization, monitoring bacterial metabolic functions, and as a mechanism for tracking the transport of relevant components through vesicles. The reduced scattering and axial confinement of the excitation offered by multiphoton imaging can be used to overcome some of the limitations of single-photon excitation (e.g., scattering and out-of-plane photobleaching) to the imaging of bacterial communities. In this work, we demonstrate in vivo multi-photon microscopy imaging of Streptomyces bacterial communities, based on the excitation of blue endogenous fluorophores, using an ultrafast Yb-fiber laser amplifier. Its parameters, such as the pulse energy, duration, wavelength, and repetition rate, enable in vivo multicolor imaging with a single source through the simultaneous two- and three-photon excitation of different fluorophores. Three-photon excitation at 1040 nm allows fluorophores with blue and green emission spectra to be addressed (and their corresponding ultraviolet and blue single-photon excitation wavelengths, respectively), and two-photon excitation at the same wavelength allows fluorophores with yellow, orange, or red emission spectra to be addressed (and their corresponding green, yellow, and orange single-photon excitation wavelengths). We demonstrate that three-photon excitation allows imaging over a depth range of more than 6 effective attenuation lengths to take place, corresponding to an 800 micrometer depth of imaging, in samples with a high density of fluorescent structures.

Background-penalty-free waveguide enhancement of CARS signal in air-filled anti-resonance hollow-core fiber.

We study coherent anti-Stokes Raman spectroscopy in air-filled anti-resonance hollow-core photonic crystal fiber, otherwise known as "revolver" fiber. We compare the vibrational coherent anti-Stokes Raman signal of N2, at ∼2331 cm-1, generated in ambient air (no fiber present), with the one generated in a 2.96 cm of a revolver fiber. We show a ∼170 times enhancement for the signal produced in the fiber, due to an increased interaction path. Remarkably, the N2 signal obtained in the revolver fiber shows near-zero non-resonant background, due to near-zero overlap between the laser field and the fiber cladding. Through our study, we find that the revolver fiber properties make it an ideal candidate for the coherent Raman spectroscopy signal enhancement.

Community as classroom: teaching and learning public health in rural Appalachia.

Traditional models for public health professional education tend to be didactic, with brief, discrete practica appended. National reports of both practitioners and academicians have called for more competency-driven, interdisciplinary-focused, community-based, service-oriented, and experientially-guided learning for students across the curriculum. East Tennessee State University began its own curricular revisioning in health professions education nearly 2 decades ago with a grant from the W.K. Kellogg Foundation, emphasizing competencies development through community-based learning in community-academic partnerships. This article describes 3 examples that grew from that initiative. In the first example, students in multiple classes delivered a longitudinal community-based employee wellness intervention for a rural county school district. BS public health students conducted needs assessments and prepared health education materials; MPH students conducted health assessments and worked with school wellness councils to deliver client-centered interventions; DrPH students supervised the project and provided feedback to the schools using participatory methods. In the second example, MPH students in a social-behavioral foundations course used experiential learning to investigate the region's elevated cancer mortality ranking. Following meetings with multiple community groups, students employed theoretical constructs to frame regional beliefs about cancer and presented findings to community leaders. One outcome was a 5-year community-based participatory research study of cancer in rural Appalachia. In the third example, MPH students in a health-consulting course assessed local African Americans' awareness of the university's health and education programs and perceptions of their community health issues. Students learned consultation methods by assisting at multiple regional African American community meetings to discover issues and interest that resulted in the organization of a regional African American health coalition, multiple community health interventions, and the region's first health disparities summit. Lessons learned are presented which identify key elements of success and factors that influence adoption of community-based teaching and learning in public health.

Intention for healthy eating among southern Appalachian teens.

OBJECTIVE: To describe the intention for healthy eating and its correlates among southern Appalachian teens. METHODS: Four hundred sixteen adolescents 14- to 16-years-old were surveyed with self-administered questionnaires. RESULTS: About 30% of the adolescents surveyed had definite intentions to eat healthfully during the next 2 weeks. The scales for perceived behavior control, attitude, perceived eating habits of significant others, and social support were shown to be fairly reliable (Cronbach's alpha=0.60 to 0.88). Perceived behavior control and attitude were positively associated with the intention for healthy eating. CONCLUSIONS: Better behavior control and more positive attitude may lead to a stronger intention for healthy eating.

NIR light propagation in a digital head model for traumatic brain injury (TBI).

Near infrared spectroscopy (NIRS) is capable of detecting and monitoring acute changes in cerebral blood volume and oxygenation associated with traumatic brain injury (TBI). Wavelength selection, source-detector separation, optode density, and detector sensitivity are key design parameters that determine the imaging depth, chromophore separability, and, ultimately, clinical usefulness of a NIRS instrument. We present simulation results of NIR light propagation in a digital head model as it relates to the ability to detect intracranial hematomas and monitor the peri-hematomal tissue viability. These results inform NIRS instrument design specific to TBI diagnosis and monitoring.

Optical architecture design for detection of absorbers embedded in visceral fat.

Optically absorbing ducts embedded in scattering adipose tissue can be injured during laparoscopic surgery. Non-sequential simulations and theoretical analysis compare optical system configurations for detecting these absorbers. For absorbers in deep scattering volumes, trans-illumination is preferred instead of diffuse reflectance. For improved contrast, a scanning source with a large area detector is preferred instead of a large area source with a pixelated detector.

Prevalence and risk factors of maternal depression during the first three years of child rearing.

BACKGROUND: This longitudinal study examined maternal depression status from birth of a child to 36 months of age using data from the National Institute of Child Health and Human Development (NICHD) Study of Early Child Care and Youth Development. METHODS: Maternal depression was assessed using the Center of Epidemiological Studies Depression Scale (CES-D) and defined as a score of ≥16. For this study, early onset depression was defined as depression within the 6 months after birth, and late onset depression was depression onset when the child was ≥24 months old. Chronic depression was defined as depression that started within 6 months after birth and lasted until 24 months of age or longer. RESULTS: The prevalence of maternal depression was 32.2% for early onset, 7.4% for late onset, and 13.4% for chronic depression. The prevalence of maternal depression was highest at 1 month, decreased at 6 months, and then remained fairly stable until 36 months. Mothers 18-24 years of age, of black race, unemployed, with lower social support, single, or with poor general health had a higher prevalence of both early and chronic depression compared to other groups. CONCLUSIONS: Younger maternal age, poverty, lower education, and lack of social support were all significantly associated with increased maternal depression in multivariate regression models. Younger age, black race, unemployment, single status, lack of social support, and poor general health were all risk factors for increased prevalence of maternal depression.

Eating habits among adolescents in rural Southern Appalachia.

A survey of 274 adolescents aged 14-16 years in rural Appalachia showed that unhealthy eating habits were prevalent. A few adolescents were teased about weight whereas 20.1% witnessed weight teasing almost everyday. Perception of parents' healthy eating and better social support for healthy eating were associated with healthier eating habits.