Carbon nanotube thin film transistors for biomedical applications.

The application of carbon nanotubes (CNTs) has captivated the curiosity of today\u27s experts due to the escalating potential in the field of electronic detection of biomolecules. Their extreme environmental sensitivity and small size make them ideal candidates for future biosensing technologies. Recent studies have shown that the binding of receptor proteins (biomolecules located at the membrane of cells) with their corresponding antibodies immobilized on a carbon nanotube surface causes changes in the electrical properties of carbon nanotubes and have been measured with a carbon nanotube field effect transistor (CNTFET). This specific molecular interaction and sensitivity is promising for the direct detection of live cells in blood. In this study, a biosensor was developed based on carbon nanotube thin film transistors for the purpose of electrically detecting breast cancer cells (MCF-7) in blood. The electrical response of specific and non-specific interactions between anchored antibodies onto the carbon nanotube film surface and breast cancer cells mixed with blood were monitored and recorded. The electrical measurements indicate that devices functionalized with specific antibodies (anti-IGF1R) experience large conductivity drops (~60 %). However for those device printed with non-specific antibodies (anti-IgG), small changes (~10 %) in conductivity are measured. It is postulated that the addition of increasing number of MCF-7cells mixed with blood on a CNT surface functionalized with specific antibodies (anti-IGF1R) acts as a chemical gate modulating the current flow. Biosensing mechanistic studies using a liquid gated CNTFET, confirmed that the specific antibody-receptor binding can be attributed to electrostatic gating effect by which cancer cells can be screened in blood

Microfluidic platform for impedance characterization of endothelial cells under fluid shear stress.

Endothelium dysfunction has been associated with many pathophysiological processes leading to cardiovascular diseases. Studying endothelium behavior is vital to understand the onset, prevention, and treatment of such diseases. Electrical impedance spectroscopy has been shown to provide a real-time in vitro evaluation of cell behavior including cell monolayer permeability. However, the majority of published work has been primarily with static cell culture models or macro-scale models that do not properly represent the physiological sizes, structures, and environmental conditions of human blood vessels. Within this dissertation, the design, fabrication, characterization, and application of a microfluidic impedance platform is presented for the in vitro characterization of HUVECs undergoing different hydrodynamic shear stress conditions (static, 2.5, 17.6 and 58.1 dyne/cm2). Electrodes diameters of 50, 100, and 200 µm were incorporated to monitor different subpopulations sizes of HUVECs. Initial characterization experiments with relevant biological solutions indicated that electrodes smaller than 50 µm in diameter suffered from significant interfacial impedance and were unsuitable for the sensing application. Impedance spectra (102-106 Hz) were collected for HUVECs at the different shear conditions for 14 hours. Equivalent circuit fits were implemented to derive the different electrical cell monolayer parameters including the trans-endothelial resistance, cell membrane capacitance, constant phase element, and the resistance of cell culture medium. Results confirmed that while the trans-endothelial resistance and cell membrane capacitance were suitable measurements for cell permeability and confluency respectively, the constant phase element did not identify any discernible cell behavior. Resistance of cell culture medium was strongly influenced by cell attachment and values should be extracted from control cell-free measurements. Initial trans-endothelial resistance measurements showed a shear magnitude dependent increase at the sudden onset of flow. This increase was greatest for the largest shear condition (58.1 dyne/cm2). After 14 hours of shear, trans-endothelial resistance measurements were largest for HUVECs sheared at 58.1 dyne/cm2 and lowest for the 17.6 dyne/cm2 shear condition and the difference showed to be statically significant (p \u3c0.05). Monitored HUVECs were stained for nuclei, F-actin and VE-cadherin. Quantification of immunofluorescence of VE-cadherin showed a similar trend to the extracted trans-endothelial resistance values. Immunofluorescence images of F-actin showed significant cytoskeleton remodeling of sheared HUVECs. While cells sheared at 17.6 dyne/cm2 aligned parallel to the direction of flow, HUVECs sheared at 58.1 dyne/cm2 were angled in the direction of flow and sometimes even perpendicular to flow direction

Investigation of Non-Lethal Electric Shock on American Crows as a Predator Aversion Treatment for Reducing Depredation on California Least Tern Eggs

The response of American crows (Corvus brachyrhynchos) to electrified eggs at the Venice Beach California least tern nesting colony was monitored throughout the 2014 season. Game cameras were deployed beside the artificial nests to record crow behavior towards the electrified eggs. Conditioned crows were defined as crows that were present within \u3c15 feet but \u3e1 foot of the electrified eggs and unconditioned crows were considered crows that were present within 1 foot of the eggs. The number of conditioned crows observed in the video clips significantly differed from a homogenous distribution using a chi-square test (p\u3c0.001). The first 5 weeks of the experiment experienced a larger number of unconditioned crows than the remaining weeks of the experiment. A modified approach to the Lincoln index was also used to estimate population flux of crows at the Venice Beach colony. The nesting California least terns at Venice Beach successfully produced fledges when this predator aversion experiment was deployed, after 5 years of no reproductive success and the 2014 fledging per pair ratio was the second highest ratio recorded in 2013 and 2014. Further multi-year research is needed to clarify the efficacy of this management intervention as there may be associated confounding variables

Documentación de las Normas Técnicas Colombianas 1022, 401 y la Resolución 1166 para la certificación del producto en la Empresa Concretos e Ingeniería - Prefabricados Concisa

La palabra "calidad" se usa cada vez con mayor frecuencia actualmente en las compañías convirtiéndose en un aspecto importante en el acceso al mercado, el cual cada día es más competitivo y exigente, es importante para las empresas garantizar un producto o servicio de calidad, confiabilidad y seguridad a quien se ofrece, por esto CONCRETOS E INGENIERÍA S.A.S de Dosquebradas se ha propuesto como medio estratégico la realización de la documentación de las normas Técnicas Colombianas 1022, 401 y la resolución 1166 para la Certificación de Producto en Tubos de concreto simple o con refuerzo otorgado por el ente ICONTEC. El fin de este proyecto es estructurar y certificar el producto antes mencionado para la empresa CONCRETOS E INGENIERIA S.A.S basándose en los requerimientos expresados en la norma técnica colombiana NTC 1022, NTC 401 y la resolución 1166 del 2006.The word quality is used with more frequency in the companies, becoming an important aspect of market access which is becoming more competitive and demanding, it is very important for companies to guarantee quality, reliability and security to those who offer it, this is why Concretos e Ingeniería S.A.S. located in Dosquebradas has proposed as a strategic medium the documentation of the technical standards of Colombia 1022, 401 and the resolution 1166 for the certification of simple concrete pipe product or reinforced given by ICONTEC. The aim of this project is to build and certify the product for the company Concretos E Ingeniería S.A.S. located Dosquebradas based on the requirements expressed in the Colombian technical standards NTC1022, NTC 401 and resolution 1166

Diagnóstico de consumo de bebidas en adolescentes que asisten a dos instituciones públicas y dos instituciones privadas en la ciudad de Portoviejo, en el período mayo 2013 a mayo 2014

El estudio tuvo como finalidad identificar el aporte calórico proveniente de las bebidas a la ingesta calórica total, con el objetivo de elaborar recomendaciones basadas en evidencia científica para los consumidores, profesionales de salud y el sector gubernamental enfocadas a mejorar los hábitos alimentarios y la salud de la población. Los resultados muestran que se consumen en promedio 2310,2 calorías, de las cuales 23,6% proviene exclusivamente de bebidas. Las bebidas más consumidas fueron los lácteos enteros, con un 9% del total de bebidas ingeridas, el cual representa 195,9kcal, que significa aproximadamente 1 ½ vaso de lácteos enteros al día o 312ml. La investigación recomienda el consumo de bebidas saludables por encima de las demás bebidas, se hace énfasis en el reemplazo de la leche entera por leche descremada. Además se sugiere que en esta ciudad, existan fuentes de agua segura en escuelas y colegios, sin restricciones de acceso físico y económico

Clima Organizacional Y Desempeño Laboral De Los Trabajadores De La Dirección Regional De Transportes Y Comunicaciones, Junín - 2018

El presente trabajo titulado: Clima Organizacional y Desempeño Laboral de los trabajadores de la Dirección Regional de Transportes y Comunicaciones – Junín 2018.Se ejecutó con el objetivo general de determinar la relación que existe entre Clima Organizacional y Desempeño Laboral de los trabajadores contratados de la Dirección Regional de Transportes y Comunicaciones – Junín 2018. Para ello se formuló el problema de investigación: ¿Cuál es la relación entre Clima Organizacional y Desempeño Laboral de los trabajadores contratados de la Dirección Regional de Transportes y Comunicaciones – Junín 2018? Formulándose la hipótesis general de relación directa entre el Clima Organizacional y Desempeño Laboral de los trabajadores contratados de la Dirección Regional de Transportes y Comunicaciones – Junín 2018. El estudio realizado se tipificó como descriptivo, el diseño fue descriptivo correlacional, se consideró una muestra de 45 trabajadores contratados. El método general utilizado es científico, y los específicos son estadístico y descriptivo, el tipo es no experimental, la técnica de la investigación utilizada es la encuesta, el instrumento utilizado es el cuestionario de encuesta, la misma se realizó la validación y confiabilidad por el experto, además de utilizar el procesamiento de datos Excel. Al finalizar la investigación se verificó que Se determinó que existe una relación moderada entre Clima Organizacional y Desempeño Laboral en los trabajadores contratados de la Dirección Regional de Transporte y Comunicaciones Junín – 2018. Luego de aplicar los instrumentos de investigación se tiene rho de spearman r s = 0,674 En consecuencia la t calculada es mayor que t teórica (4,31 > 2,01)

Expansión urbana. Aproximación Picaleña, Ibagué 2000-2020

En este documento se analizaron las características del proceso de expansión y desarrollo urbano sobre el sector de picaleña del municipio de Ibagué en los últimos 20 años, asociado a las transformaciones que se realizan sobre el territorio y la forma como cada cultura se apropia del lugar. Esta caracterización se enfoca en los antecedentes teóricos sobre los procesos de expansión y desarrollo urbano y las políticas de planeación del territorio, realizando un recorrido del contexto global al loca

Development and in vitro evaluation of extended-release theophylline matrix capsules

Cápsulas de liberação modificada contendo 100 mg de teofilina foram preparadas com polímeros derivados da celulose (Methocel® K100MPRCR, K15MPRCR e E4MCR) em diferentes concentrações, 15-35%, empregando-se o método volumétrico. Estudos de liberação do fármaco foram realizados de acordo com a Farmacopéia Americana 28 ed., (Teste 8), empregando aparato 1, rotação de 100 rpm e temperatura de 37 ºC em 900 mL de meio fluido intestinal sem enzimas (pH 7,5). Os perfis de dissolução foram comparados ao de duas especialidades farmacêuticas comerciais. A formulação, com 35% de Methocel® E4MCR, evidenciou perfis de liberação de acordo com as especificações e os resultados foram reprodutíveis para 10 lotes manipulados com a mesma formulação. As cápsulas comerciais de liberação prolongada contendo 100 mg de teofilina (microgrânulos), submetidas ao mesmo ensaio, apresentaram rápida liberação do fármaco, indicando que a liberação não é fator limitante para a absorção. Avaliou-se a cinética de liberação do fármaco empregando os modelos matemáticos de ordem zero, primeira ordem e Higuchi. Conclui-se que as matrizes obtidas foram capazes de modular a liberação, envolvendo os mecanismos de difusão e erosão, prevalecendo o modelo de primeira ordem e que as cápsulas de liberação modificada podem ser manipuladas, desde que testes de liberação sejam realizados.Polymers like cellulose (MethocelTM K100MPRCR, K15MPRCR and E4MCR) at different proportions (15-35%) were used to slow the release of theophylline (100 mg) from capsules. Volumetric method for powder filling capsules was used to prepare the capsules. Drug release from capsules was performed using apparatus 1, at 100 rpm and 900 mL of intestinal medium without enzymes (pH 7.5), at 37 °C, following the USP 28th ed. (Test 8). Dissolution profiles were compared to two batches of commercial extended-release capsules. Capsules compounded with 35% (wt/wt) of MethocelTM E4MCR showed dissolution profile according to the official especifications. Similar results were reproduced with other ten compounded batches. Commercial extended-release capsules containing theophylline pellets (100 mg) showed quick drug release when submitted to the same test, indicating that, in these conditions, the capsules did not show prolonged release. Mathematical models like zero-order, first-order and Higuchi were applied in kinetic studies of theophylline release from the compounded capsules. Polymers were efficient to control the release of theophylline in capsules involving diffusion and erosion as mechanisms, and that first-order model was the best fitted one for theophylline matrix capsules. These results support that compounded extended-release capsules can be prepared, since the drug release tests can be done

What traits underpin the successful establishment and spread of the invasive water bug Trichocorixa verticalis verticalis?

The introduction of exotic species has a major impact on a wide range of ecosystems, especially in aquatic ecosystems. Trichocorixa v. verticalis (Fieber, 1851), an euryhaline aquatic hemipteran native North America, has occurred as an exotic species in the Iberian Peninsula since at least 1997. In this study, we compared several physiological and biological traits (salinity tolerance of the different developmental stages, thermal tolerance, fecundity, and dispersal ability) in the alien species and three native, syntopic corixidae species (Sigara lateralis, Sigara scripta, and Sigara selecta), to determine which traits may explain its invasion success. Trichocorixa verticalis was the species most resistant to high conductivity at the egg stage, while S. selecta showed the highest halotolerance as adults. The invader had the highest upper thermal limit and a much higher fecundity than Sigara species. Wing morphometry suggested that T. verticalis may be a stronger flier than the native species. Our findings provide an example of how functional and ecological niche interactions among alien and native species can help predict impacts of invasion on aquatic communities.Peer Reviewe