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BACKGROUND: Due to the rising demands for a Canadian workforce with science, technology, engineering, and math (STEM)-related education, there is a need to increase youth engagement in STEM education and programming. Research, however, has shown that youth residing in low-income communities are disproportionately affected by psychosocial barriers, which often inhibit meaningful engagement in STEM programming. Visions of Science Network for Learning (VoSNL) was designed and implemented to address these existing barriers. VoSNL is a charitable organization in Southern Ontario, Canada, that provides weekly community-based STEM programming to low-income and marginalized youth during out-of-school time. VoSNL programming is delivered directly within the community and is free-of-charge for all youth in order to minimize barriers of physical and financial accessibility. The purpose of this report was to provide a detailed description of a core program within VoSNL-Community Science Clubs-and summarize the findings of a process evaluation, specifically the successes and challenges of implementing a community-based, out-of-school STEM program. RESULTS: Program successes are outlined along with the challenges that have been identified through program implementation. Successes include (a) delivering the program within a community context, (b) opportunities for consistent engagement, and (c) establishing positive youth-staff relationships. Challenges include (a) navigating community-based issues, (b) conducting outreach and promotion, and (c) accommodating a wide age range of youth. Further, lessons learned from an evaluation of program implementation are also discussed. CONCLUSIONS: This report provides one of the first program descriptions and process evaluations of a community-based, youth-focused STEM program within a Canadian context. The findings in this report have helped to improve the delivery and evaluation of the VoSNL program and may act as a catalyst for program expansion to reach more youth in marginalized communities. Further, the findings can also provide a strong framework for programmers interested in implementing STEM youth programming in a community context, assist in the replication of similar models in other locations, and enhance STEM learning amongst youth.

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Epidermal growth factor (EGF) binding to its receptor (EGFR) activates several signaling intermediates, including Akt, leading to control of cell survival and metabolism. Concomitantly, ligand-bound EGFR is incorporated into clathrin-coated pits--membrane structures containing clathrin and other proteins--eventually leading to receptor internalization. Whether clathrin might regulate EGFR signaling at the plasma membrane before vesicle scission is poorly understood. We compared the effect of clathrin perturbation (preventing formation of, or receptor recruitment to, clathrin structures) to that of dynamin2 (allowing formation of clathrin structures but preventing EGFR internalization) under conditions in which EGFR endocytosis is clathrin dependent. Clathrin perturbation by siRNA gene silencing, with the clathrin inhibitor pitstop2, or knocksideways silencing inhibited EGF-simulated Gab1 and Akt phosphorylation in ARPE-19 cells. In contrast, perturbation of dynamin2 with inhibitors or by siRNA gene silencing did not affect EGF-stimulated Gab1 or Akt phosphorylation. EGF stimulation enriched Gab1 and phospho-Gab1 within clathrin structures. ARPE-19 cells have low ErbB2 expression, and overexpression and knockdown experiments revealed that robust ErbB2 expression bypassed the requirement for clathrin for EGF-stimulated Akt phosphorylation. Thus clathrin scaffolds may represent unique plasma membrane signaling microdomains required for signaling by certain receptors, a function that can be separated from vesicle formation.

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Receptor tyrosine kinases (RTK) are an important family of growth factor and hormone receptors that regulate many aspects of cellular physiology. Ligand binding by RTKs at the plasma membrane elicits activation of many signaling intermediates. The spatial and temporal regulation of RTK signaling within cells is an important determinant of receptor signaling outcome. In particular, the compartmentalization of the plasma membrane into a number of microdomains allows context-specific control of RTK signaling. Indeed various RTKs are recruited to and enriched within specific plasma membrane microdomains under various conditions, including lipid-ordered domains such as caveolae and lipid rafts, clathrin-coated structures, tetraspanin-enriched microdomains, and actin-dependent protrusive membrane microdomains such as dorsal ruffles and invadosomes. We examine the evidence for control of RTK signaling by each of these plasma membrane microdomains, as well as molecular mechanisms for how this spatial organization controls receptor signaling.

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Objetivo: Determinar las características clínicas del paciente con tuberculosis (TBC) pulmonar bacilífera, del Hospital Regional de Loreto (HRL) de enero de 1998 a diciembre del 2002. Materiales y Métodos: Es un trabajo descriptivo, retrospectivo, transversal. Se revisó la ficha clínica de 271 pacientes con tuberculosis pulmonar bacilífera que ingresaron al programa de control de tuberculosis del HRL durante 5 a±os. Resultados: De los 271 pacientes el tiempo de enfermedad mßs frecuente fue mayor que 1 mes a 6 meses (44.7 por ciento), de inicio insidioso (93 por ciento), los signos y síntomas predominantes fueron tos (96.7 por ciento), baja de peso (86 por ciento), expectoración (83 por ciento) y pérdida del apetito (72.3 por ciento); al examen pulmonar predominaron respiración ruda(29.2 por ciento), subcrépitos (28.8 por ciento); las radiografías patológicas mostraron compromiso pulmonar bilateral (43.3 por ciento), 38 por ciento fueron BK(+) y 31 por ciento BK(+++), la baciloscopía de esputo fue positiva en la primera muestra en 64.2 por ciento y solo 18.1 por ciento presentaron enfermedad asociada, principalmenteanemia y diabetes mellitus. Conclusiones: Los pacientes con TBC pulmonar bacilífera presentaron un tiempo de enfermedad 1-6 meses, inicio insidioso, con tos, baja de peso, expectoración y pérdida del apetito; con respiración ruda y subcrépitos al examen, compromiso pulmonar bilateral en la radiografía; BK(+) y baciloscopía positiva en la primera muestra de esputo.

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