Electrochemical Focal Hypoxia for Cell Models

For the last few decades, there has been increasing attention to hypoxia’s (low oxygen) contribution to poor prognosis and ineffective treatments. Despite existing physiologically, hypoxia is a pathological accompaniment in a myriad of diseases, including tumour, stroke, dementia and cardiovascular diseases, that causes damage locally and to surrounding tissues. The inflicted damage is particularly significant in the brain which uses 20% of the body’s total oxygen supply and has limited energy storage. Currently common hypoxia models such as low oxygen incubators, hypoxia chambers and chemical hypoxia have two major flaws: no spatial control and long equilibration time. It is not possible to induce hypoxia focally such that these approaches have very limited translatability and resemblance to the physiology and pathophysiology of the local tissue. Thus, our ability to focus on the geography of events emerging from hypoxia has been limited. This thesis addressed the spatiotemporal limitation of existing hypoxia models and investigated oxygen removal by electrochemical reduction in culture media. The platinum/graphite (Pt/C) electrode had a large surface area and showed promising catalytic properties for the oxygen reduction reaction in the culture media. The oxygen scavenging system effectively generated hypoxia at the base of the electrochemical cell in 7 minutes from normoxia, contrasting with hours needed by conventional methods. Its flexibility in reshaping and positioning were also beneficial to generating patterns of hypoxia gradient. Upon application to human cells, the electrochemical oxygen scavenging system was proven to induce spatiotemporal response of HIF-1α transcription factor in neural progenitor cells. The system was also applied in a human cerebral microchannel model which was the first known in vitro model to demonstrate that 10-minute focal hypoxic stress on the axons caused the induction of apoptosis in human cortical neurons, observed in the distant cell bodies.Croucher Cambridge International Scholarship; Cambridge Trus

Uplifting Diverse and Marginalized Voices Through Community Archives and Public Programming

Queens Memory is a local community archiving project co-administered by the Queens Public Library and Queens College Library. During the COVID-19 pandemic, Queens Memory embarked on a collaborative series of online programs that covered social justice, current events, and the creation of social change. This programming built upon ongoing community oral history and documentation efforts. This article explores how the public programs and oral history initiatives fueled one another, serving to uplift diverse voices within our communities and preserve those voices in the archives. Key ingredients of the programs are discussed, including technology, outreach, collaboration, consent, and format

Comparative study of attenuation and dispersion of different pressure disturbances propagating in aerosols

This study aims to investigate the attenuation and dispersion of pressure waves propagating in aerosols. A numerical scheme based on Crank-Nicolson finite differencing and trapezoidal quadrature discretization methods is employed to simulate the evolutions of several pressure waves with different initial profiles (disturbances)

Gestión logística y calidad de servicio en los almacenes de la DIGERD del MINSA, Lima 2022

La importancia de la gestión logística, en los almacenes toman mayor relevancia ante las diferentes necesidades de las personas tanto en productos como en servicios. En la actualidad, afrontando una emergencia sanitaria, la COVID-19 ha evidenciado las falencias que poseen las entidades del sector público y privado para brindar servicios de calidad, y es que surge la incógnita, que es la calidad, de quien depende, como se percibe, etc. La defino como el cumplimiento de las cualidades de un producto (producto se refiere también a servicio) frente a los requerimientos de un cliente. La presente investigación se aplicó dentro de los almacenes de la dirección general de gestión del riesgo de desastres y defensa nacional en salud (en adelante DIGERD) del MINSA, la cual es una dirección general que tiene la responsabilidad de tener a disposición la oferta flexible del MINSA ante una emergencia o desastre. La finalidad es encontrar si existe correlación entre la gestión logística (en adelante GL) y la calidad de servicio (en adelante CS) en los almacenes de DIGERD, es de tipo básica y cuantitativa, ya que se mide y describe la GL y CS en los almacenes de la DIGERD, mediante instrumentos estructurados y valorados en escala de Likert, el diseño es no experimental, descriptivo, transversal. Los resultados se encontraron a través de dos instrumentos validados por un juicio de expertos, los cuales tuvieron 19 ítems (para la GL) y 20 ítems (para la CS), asimismo su confiabilidad se obtuvo luego de aplicar el coeficiente de Alphade Cronbach dando como resultado .899 y .835. Respecto a la hipótesis, se rechaza la hipótesis nula y se establece que la GL se relaciona de manera significativa con la CS en los almacenes de la DIGERD, 2022

Reliability and validity of psychosocial and environmental correlates measures of physical activity and screen-based behaviors among Chinese children in Hong Kong

Background : Insufficient participation in physical activity and excessive screen time have been observed among Chinese children. The role of social and environmental factors in shaping physical activity and sedentary behaviors among Chinese children is under-investigated. The purpose of the present study was to assess the reliability and validity of a questionnaire to measure child- and parent-reported psychosocial and environmental correlates of physical activity and screen-based behaviors among Chinese children in Hong Kong. Methods : A total of 303 schoolchildren aged 9-14 years and their parents volunteered to participate in this study and 160 of them completed the questionnaire twice within an interval of 10 days. Intraclass correlation coefficients (ICCs), kappa statistics, and percent agreement were performed to evaluate test-retest reliability of the continuous and categorical variables, respectively. Exploratory factor analyses (EFAs) were conducted to assess convergent validity of the emergent scales. Cronbach\u27s alpha and ICCs were performed to assess internal and test-retest reliability of the emergent scales. Criterion validity was assessed by correlating psychosocial and environmental measures with self-reported physical activity and screen-based behaviors, measured by a validated questionnaire. Results : Reliability statistics for both child- and parent-reported continuous variables showed acceptable consistency for all of the ICC values greater than 0.70. Kappa statistics showed fair to perfect test-retest reliability for the categorical items. Adequate internal consistency and test-retest reliability were observed in most of the emergent scales. Criterion validity assessed by correlating psychosocial and environmental measures with child-reported physical activity found associations with physical activity in the self-efficacy scale (r = 0.25, P &lt; 0.05), the peer support for physical activity scale (r = 0.25, P &lt; 0.05) and home physical activity environmental (r = 0.14, P &lt; 0.05). Children\u27s screen-based behaviors were associated with the family support for physical activity scale (r = -0.22, P &lt; 0.05) and parental role modeling of TV (r = 0.12, P = 0.053). Conclusions : The findings provide psychometric support for using this questionnaire for examining psychosocial and environmental correlates of physical activity and screen-based behaviors among Chinese children in Hong Kong. Further research is needed to develop more robust measures based on the current questionnaire, especially for peer influence on physical activity and parental rules on screen-based behaviors. <br /