Propiedades de transporte de co-solutos en hidrogeles termosensibles

129 páginas. Doctorado en Ciencias e Ingeniería de Materiales.En este trabajo presentamos un estudio acerca de la transferencia de masa de diferentes cosolutos a través de partículas de hidrogeles de poli N-Isopropilacrilamida (pNIPAM) en soluciones acuosas. Estos cosolutos son: fenol, 5- Fluorouracilo (5FU), metano y metanol. El estudio se aborda desde distintas perspectivas: combinando cálculos teóricos, simulaciones computacionales de dinámica molecular átomo-por-átomo y grano-grueso, y comparando con reportes experimentales. Las partículas de hidrogel son diseñadas con estructuras rellenas o huecas, y en particular estudiamos los procesos de encapsulación/liberación de fenol hacia/desde ellas. En la primera etapa del proyecto diseñamos un modelo original de tipo grano-grueso para geles de pNIPAM, el cual captura de forma adecuada la transición bobina-glóbulo y glóbulo-bobina del polímero. Con este modelo construimos arreglos poliméricos complejos aproximados a un hidrogel, como lo es una membrana, con los cuales se observa una mejora en el consumo de recursos de las simulaciones de hasta 54 veces. Por otra parte, los cálculos teóricos son abordados mediante la teoría del funcional de la densidad dinámico (DDFT, por sus siglas en inglés), a partir de la cual obtenemos los perfiles de densidad del cosoluto y su evolución en el tiempo. La DDFT es una técnica que permite el estudio a nivel molecular de la dinámica de sistemas Fickianos en los que los modos hidrodinámicos no son relevantes, mediante la única hipótesis de que podemos aproximar las correlaciones dinámicas por las que existirían en un sistema equivalente (con igual perfil de densidad) en equilibrio. A diferencia de otros modelos que consideran una difusión ideal, la DDFT toma en cuenta la interacción efectiva entre el polímero y el cosoluto (U ef) y entre moléculas de cosoluto, para calcular el potencial químico de la carga dentro del hidrogel, y a partir de esto, su flujo. Además, la DDFT requiere de una definición explícita del coeficiente de difusión efectivo del cosoluto dentro de la matriz de hidrogel (D ef ). Estos parámetros se extraen de simulaciones computacionales tipo átomo-por-átomo. La interacción U ef se obtiene a partir de la energía libre de trasporte, la cual se calcula con el método de relación de aceptación de Bennett (BAR en inglés). Por su parte, el D ef se calcula a partir del desplazamiento cuadrático medio de las partículas de prueba embebidas en el hidrogel y la relación de Stokes-Einstein. La validez y la implementación del método de resolución de la DDFT es probada comparando sus resultados contra simulaciones de dinámica molecular átomo-por-átomo en condiciones análogas, esto es, para la absorción de fenol en un hidrogel hueco de pNIPAM. Las predicciones teóricas y las simulaciones muestran resultados casi idénticos para los perfiles de distribución de carga y velocidades de absorción. Finalmente, realizamos una comparación entre los resultados de la DDFT con reportes experimentales obtenidos de la literatura para laliberación de fenol desde hidrogeles completamente rellenos. La longitud típica de escalado con que normalizamos las unidades en la DDFT es ajustada a las dimensiones del microgel experimental, al igual que las concentraciones iniciales. Las curvas de liberación de cosolutos obtenidas con DDFT coinciden satisfactoriamente (dentro de la misma escala temporal) con los experimentos.In this work,we studied the mass transport of different co-solutes, namely: phenol, 5FU, methane, and methanol, through pNIPAM hydrogel particles in aqueous solutions. The study is carried out by different approaches: combining theoretical calculations, all-atom and coarse-grained simulations, and also comparisons with experimental reports. The hydrogel particles are designed as solid and hollow hydrogels, and particularly we studied the encapsulation/release process of phenol cargo molecules to/from them. In the first part of the project, we devised a novel coarse-grained model for pNIPAM, which adequately captures the experimentally observed coilto-globule and globule-to-coil transitions of the polymer. With that model we build large polymer arrangements as membrane-like hydrogels and the simulation performance improves up to 54 times. On the other hand, the theoretical calculations are conducted via the dynamic density functional theory (DDFT), from which we obtain the time evolution cargo density profiles. DDFT is a technique for studying Fickian systems at a molecular level where the hydrodynamic modes are irrelevant. The hypothesis behind DDFT is that we can approximate the dynamic behavior by an equivalent (the same density profile) system in equilibrium. Unlike ideal diffusion models, this theory takes into account the polymer-cargo (Uef ) and cargo-cargo interactions to calculate the chemical potential of co-solute in the system and, from there, the flux. Also, DDFT requires an explicit definition of the effective diffusion coefficient of cargo inside the hydrogel matrix. Uef is obtained from the Free Energy of transport calculated via Bennets Acceptance Ratio method, while Def is computed from the mean square displacement (MSD) of cargo molecules inside the matrix using the Stokes-Einstein relationship. We tested our implementation of the DDFT by analyzing the absorption of phenol in a hollow hydrogel and comparing its results against all-atom MD simulations in corresponding conditions, that is, the phenol absorption into a hollow pNIPAM hydrogel. Theory and simulations show almost identical cargo distribution profiles and absorption rates. Finally, we compare the DDFT outcomes with those from experimental reports for the liberation of phenol from solid hydrogels. We change the characteristic length used to normalize the units in the DDFT code to match the same dimensions and initial cargo concentration as the experimental particles, which correspond to microgel-size ones. The DDFT release curve compares well enough within the same time scale of experiments.Investigación realizada con el apoyo del Programa Nacional de Posgrados de Calidad del Consejo Nacional de Ciencia y Tecnología (CONACYT)

Bacterias uropatógenas que expresan el morfotipo filamentoso en orinas de pacientes ambulatorios

"De las infecciones urinarias, únicamente las que se localizan a nivel renal son consideradas como causa de complicaciones a largo plazo, tales como hipertensión, proteinuria, toxemia e insuficiencia renal. El diagnóstico oportuno y tratamiento adecuado son indispensables para evitar el acenso y diseminación del patógeno y prevenir estas complicaciones. Tradicionalmente se describe que para establecer un diagnóstico de ITU se deben tomar en cuenta signos y síntomas como es el dolor lumbar, ardor al orinar, orina con olor fuerte, disuria y tenesmo vesical. En los estudios de laboratorio como auxiliar de diagnóstico se emplea el examen general de orina donde se utilizan como indicadores de ITU la esterasa leucocitaria y nitritos positivos en el análisis fisicoquímico, además de la observación microscópica con objetivo seco fuerte (40X) de bacterias abundantes, más de 15 leucocitos por campo, también la presencia de 5 o más eritrocitos por campo; otorgando una probabilidad de infección cercana al 86%"

Wireless connection of bioimpedance measurement circuits based-on AD5933: A state of the art

This contribution describes the state of the art in bioimpedance measurements through development boards to build portable devices that perform in-situ measurements and potential technological opportunities to separate the AD5933 integrated circuit from a PC. The presented research is based on prototypes developed with the aim of achieving portability with the AD5933 integrated circuit and it includes different wireless connection methods and a varied software design for the acquisition, visualization and storage of data obtained from biological systems. As a result, this work describes twenty articles that perform wireless connectivity using different microprocessors for different applications. These references seek to explore technological trends, deficiencies, and opportunities for future development projects in telemedicine.Fil: Dell'osa, Antonio Héctor. Universidad Nacional de Tierra del Fuego. Instituto de Desarrollo Economico E Innovacion; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; ArgentinaFil: Apátiga Pérez, D. S.. Instituto Politécnico Nacional. Centro de Investigación y de Estudios Avanzados. Departamento de Investigaciones Educativas.; MéxicoFil: Suárez Pérez, K. I.. Instituto Politécnico Nacional. Centro de Investigación y de Estudios Avanzados. Departamento de Investigaciones Educativas.; MéxicoFil: Ramírez Barrios, M.. Instituto Politécnico Nacional. Centro de Investigación y de Estudios Avanzados. Departamento de Investigaciones Educativas.; México4th Latin American Conference on Bioimpedance 2021San Luis PotosíMéxicoSocieda Mexicana de Ingeniería Biomédic

Methodology of Energy Management in Housing and Buildings of Regions with Hot and Dry Climates

In this chapter, power consumption and electrical demand in buildings or housing due to the utilization of HVAC systems are shown to be intimately linked to construction materials. This work proposes a methodology of energy management intended to analyze and evaluate actions aimed at saving and efficient use of electric energy of HVAC systems applied to regions with hot and dry climates. The methodology consists of: (1) characterization of local climatology using the concept of degree-hours (DH). (2) Utilization of a Fourier-type mathematical model to calculate hourly temperature using only daily maximum and minimum temperatures as well as an empirical model to compute energy efficiency (EER) of air-cooled air conditioning units. (3) Thermal simulation applying a software developed by the authors based on ASHRAE\u27s Transfer Functions methodology to calculate hourly cooling loads, the adequate sizing of air conditioning equipment and the rate of heat extraction. (4) System analysis, identification of improvement actions, evaluation of viable alternatives of saving and efficient use of energy. The advantage of this proposal is its flexibility because it can be applied to any climatology and easily adaptable to the conditions of energy usage anywhere in the world

Biocatalytic oxidative kinetic resolution of (±)-4-(chlorophenyl)phenylmethanol by Nocardia corallina B-276

Chiral diarylmethanols are versatile building blocks for the preparation of biologically active substances, but they are difficult to obtain in enantiopure form. We used Nocardia corallina B-276 for the oxidative kinetic resolution of (±)-4-(chlorophenyl)phenylmethanol, 1. Two experimental methods were used: 1) Suspension of cells in a phosphate buffer solution and 2) Cells in the culture media, in a 3-L bioreactor. After 36 hrs using the first method, the ketone/alcohol ratio was 56/44 and the unoxidized alcohol had an enantiomeric ratio of 93/7, predominating the R-alcohol

Metodología para la medición de la huella hídrica en la producción de tilapia, cachama y trucha: estudios de caso para el Valle del Cauca (Colombia)

(Eng) The pisciculture sector in Colombia, has grown 13% annually between 1988 and 2013, and it is the sixth major water user. Considering the influence that pisciculture has over the water resources, the water footprint of pisciculture was studied as a sustainability indicator, a method was developed to estimate the water footprint of the sector, which include not only the direct and indirect components, but also the green, blue and grey water footprint. The method was applied to the three most produced species in the country: tilapia (Oreochromis mossambicus), cachama (Piaractus brachypomus) and trout (Oncorhynchus mykiss), to corresponding case studies in Valle del Cauca, Colombia. It was found that the water footprint of tilapia culture is 5,486 m3/Ton, cachama culture is 6,193 m3/Ton, and trout culture is 19,854 m3/Ton. The highest total water footprint for tilapia was that of the concentrated feed, followed by the blue water footprint, associated with the amount of water that remains stored in the ponds, whereas for the cachama and trout, the highest water footprint was grey, due to the high concentrations of solids and nutrients present in fish excretions and unconsumed feed.(Spa) El sector piscícola en Colombia creció en promedio 13% anual de 1988 a 2013 y es el sexto mayor usuario de agua en el país. Considerando la presión que ejerce la producción piscícola sobre las fuentes de agua, se estudió la huella hídrica (HH) de la piscicultura como un indicador de sostenibilidad. Para ello se desarrolló una metodología que mide la HH en el sector, que incluye sus componentes directos e indirectos, así como las huellas hídricas verde, azul y gris. La metodología se aplicó a las tres especies piscícolas más producidas en el país: tilapia (Oreochromis mossambicus), cachama (Piaractus brachypomus) y trucha (Oncorhynchus mykiss), para sendos casos de estudio en el Valle del Cauca, Colombia. Se encontró que la HH total del cultivo de tilapia es de 5,486 m3/Ton, la del cultivo de cachama de 6,193 m3/Ton y la del cultivo de trucha de 19,854 m3/Ton. La huella hídrica total más alta para la tilapia fue la del alimento concentrado, seguida por la huella hídrica azul, asociada a la cantidad de agua que permanece almacenada en los estanques; en la cachama y trucha la mayor huella hídrica total fue la gris, relacionada con las altas concentraciones de sólidos y nutrientes, presentes en las excretas de los peces y en el alimento concentrado no consumido

Low-Voltage 0.81mW, 1-32 CMOS VGA with 5% Bandwidth variations and 38dB DC rejection

A CMOS low-voltage amplifier with approximately constant bandwidth and DC rejection is introduced. The design is based on the cascade of a wide linear input range OTA, an op-amp and a servo-loop with extremely large time constants. It operates with ±0.45V supplies and a power consumption of 0.81mW in 180nm technology. The bandwidth changes only from 9.08MHz to 9.54MHz over a gain range from 1 to 32, it has a 9.8Hz low cutoff frequency and a DC attenuation of 38dBs. DC floating voltage sources are used to keep the gates of all differential pairs at a constant value close to a supply rail in order to operate the amplifier circuit with minimum supply voltage. The proposed circuit has small and large signal figures of merit FOM SS = 5380 (MHz*pF/mW) and FOM LS = 0.0085((V/ns)*pF/mA) for a nominal gain A = 32

Feasibility and impact of online HIV/STI screening addressed to men who have sex with men and transgender women users of pre-exposure prophylaxis (PrEP) in Spain (TESTATE PrEP): a study protocol for a non-blinded randomised controlled trial

HIV & AIDS; Clinical trial; Sexually transmitted diseaseVIH y SIDA; Ensayo clínico; Enfermedad de transmisión sexualVIH i sida; Assaig clínic; Malaltia de transmissió sexualIntroduction The objectives of the study are: to design and implement a pilot intervention to offer self-sampling kits to detect HIV, Chlamydia trachomatis (CT), Neisseria gonorrhoeae (NG) and Treponema pallidum (TP) among gay, bisexual and other men who have sex with men and transgender women users of pre-exposure prophylaxis (PrEP) as part of PrEP follow-up. To evaluate if the pilot intervention causes a reduction of the retention to PrEP follow-up among the target population. To analyse the capacity of the intervention to reduce the healthcare burden on the PrEP service. To evaluate the acceptability of the intervention among PrEP users and PrEP service healthcare workers and; to validate dried blood samples for treponemal and non-treponemal antibody detection using the Dual Path Platform syphilis screening and confirmatory assay compared with blood drawn by venous puncture. Methods and analysis We will perform a non-blinded randomised controlled non-inferiority trial among PrEP users on follow-up. Participants on the control arm will follow the usual follow-up protocol with quarterly face-to-face visits where they will be tested for HIV and sexually transmitted infections (STIs). Participants in the experimental arm will alternate face-to-face meetings with online screening of HIV and STIs. The website https://testate.org/ will include a module for online follow-up visits of participants. Participants of the experimental arm will order self-sampling kits for HIV, CT, NG and TP through the website, will send the samples to the laboratory and check their results online. We will compare the retention to follow up and the healthcare burden in both arms. The acceptability of the intervention among participants and healthcare workers will be assessed. Ethics and dissemination The project has been approved by the CEIC-HUGTIP (Reference: PI-22-051). Subjects will be included after giving their informed consent. Final conclusions and recommendations will be shared with stakeholders. Two publications in peer-reviewed journals are expected. Trial registration number NCT05752643.This work was supported by the Instituto de Salud Carlos III (PI21/01589) and the Ministry of Health of the Government of Catalonia (Spain) (no grant number)