New biotechnological perspectives of a NADH oxidase variant from Thermus thermophilus HB27 as NAD+-recycling enzyme

<p>Abstract</p> <p>Background</p> <p>The number of biotransformations that use nicotinamide recycling systems is exponentially growing. For this reason one of the current challenges in biocatalysis is to develop and optimize more simple and efficient cofactor recycling systems. One promising approach to regenerate NAD⁺pools is the use of NADH-oxidases that reduce oxygen to hydrogen peroxide while oxidizing NADH to NAD⁺. This class of enzymes may be applied to asymmetric reduction of prochiral substrates in order to obtain enantiopure compounds.</p> <p>Results</p> <p>The NADH-oxidase (NOX) presented here is a flavoenzyme which needs exogenous FAD or FMN to reach its maximum velocity. Interestingly, this enzyme is 6-fold hyperactivated by incubation at high temperatures (80°C) under limiting concentrations of flavin cofactor, a change that remains stable even at low temperatures (37°C). The hyperactivated form presented a high specific activity (37.5 U/mg) at low temperatures despite isolation from a thermophile source. Immobilization of NOX onto agarose activated with glyoxyl groups yielded the most stable enzyme preparation (6-fold more stable than the hyperactivated soluble enzyme). The immobilized derivative was able to be reactivated under physiological conditions after inactivation by high solvent concentrations. The inactivation/reactivation cycle could be repeated at least three times, recovering full NOX activity in all cases after the reactivation step. This immobilized catalyst is presented as a recycling partner for a thermophile alcohol dehydrogenase in order to perform the kinetic resolution secondary alcohols.</p> <p>Conclusion</p> <p>We have designed, developed and characterized a heterogeneous and robust biocatalyst which has been used as recycling partner in the kinetic resolution of <it>rac</it>-1-phenylethanol. The high stability along with its capability to be reactivated makes this biocatalyst highly re-useable for cofactor recycling in redox biotransformations.</p

Improving air quality in metropolitan Mexico City : an economic valuation

Mexico City has for years experienced high levels of ozone and particulate air pollution. In 1995-99 the entire population of the Mexico City metropolitan area was exposed to annual average concentrations of fine particulate pollution (particulates with a diameter of less than 10micrometers, or PM10) exceeding 50 micrograms per cubic meter, the annual average standard in both Mexico and the United States. Two million people were exposed to annual average PM10 levels of more than 75 micrograms per cubic meter. The daily maximum one-hour ozone standard was exceeded at least 300 days a year. The Mexico Air Quality Management Team documents population-weighted exposures to ozone and PM10 between 1995 and 1999, project exposures in 2010, and computes the value of four scenarios for 2010: A 10 percent reduction in PM10 and ozone. A 20 percent reduction in PM10 and ozone. Achievement of ambient air quality standards across the metropolitan area. A 68 percent reduction in ozone and a 47 percent reduction in PM10 across the metropolitan area. The authors calculate the health benefits of reducing ozone and PM10 for each scenario using dose-response functions from the peer-reviewed literature. They value cases of morbidity and premature mortality avoided using three approaches: Cost of illness and forgone earnings only (low estimate). Cost of illness, forgone earnings, and willingness to pay for avoided morbidity (central case estimate). Cost of illness, forgone earnings, willingness to pay for avoided morbidity, and willingness to pay for avoided mortality (high estimate). The results suggest that the benefits of a 10 percent reduction in ozone and PM10 in 2010 are about $760 million (in 1999 U.S. dollars) annually in the central case. The benefits of a 20 percent reduction in ozone and PM10 are about$1.49 billion annually. In each case the benefits of reducing ozone amount to about 15 percent of the total benefits. By estimating the magnitude of the benefits from air pollution control, the authors provide motivation for examining specific policies that could achieve the air pollution reductions that they value. They also provide unit values for the benefits from reductions in ambient air pollution (for example, per microgram of PM10) that could be used as inputs into a full cost-benefit analysisof air pollution control strategies.Montreal Protocol,Public Health Promotion,Global Environment Facility,Air Quality&Clean Air,Health Monitoring&Evaluation,Montreal Protocol,Air Quality&Clean Air,Health Monitoring&Evaluation,Global Environment Facility,Transport and Environment

Minority compounds and sensory analysis evaluation of Coffea arabica var. caturra cultivated in three different altitudinal ranges

The composition of minority compounds in samples of roasted and ground coffee (Coffea arabica var. caturra) cultivated in three altitudinal ranges 1300-1400, 1400-1600, 1600-1800 m. a. s. l., in the Huila department of Colombia were determined. The samples were collected in July of 2012. pH, total acidity and total lipids were measured. Subsequently, the composition of total lipids after esterification and gas chromatography analysis coupled to high resolution mass spectrometry (GC-MS) was established. Quality cup test considering the following attributes:  fragrance/aroma, taste, residual flavor, acidity, body, uniformity, balance, clean cup, sweetness, quality and note, were performed. No statistically significant difference (p 0.05) in pH, titratable acidity, total time of roasting and cracking time was determined. Significant difference was found in% humidity range: 1300-1400 m relative to the ranges: 1400-1600 and 1600-800 meters. As for the major compounds are predominantly: stigmasterol, sitosterol, 4-methylpentanamide and 2- (2-hydroxyphenyl) buta-1,3-diene, in the altitudinal ranges evaluated. No significant difference (p0.05) was found in the evaluated attributes at the quality cup test at different altitudinal range

SiC-Based Multilayer for Applications in Extreme Environment - H2 Generation Plants

The purpose of this research is to develop SiC-based multilayers, for applications in extreme environment such as H2 generation plants. Tape casting technology, followed by debinding and sintering at very high temperature (~2200 °C) has been used. In Europe H2 generation processes are being studied under the project HycycleS1, that focuses at the qualification and enhancement of materials and components, in particular ceramics of the SiC family, for key steps of thermochemical cycles for solar or nuclear hydrogen generation. SiC-based materials for applications in extreme environments are developed within the European project ExtreMat. This project has identified the generation of hydrogen as a possible spin off of research activities. HycycleS (Materials and components for Hydrogen production by sulphur based thermochemical cycles) is a project funded under 7th Framework Programme. ExtreMat is funded within the 6th Framework Programme and it targets on the creation of new multifunctional materials. The aim of this research is to develop multilayer SiC for applications in hydrogen generation plants based on thermochemical cycle "S-I" or cycle hybrid thermochemical-electrolytic. The structured components of such facilities (tanks, tubular heat exchangers, etc) should have excellent thermal stability at high temperature, corrosion resistance (in the presence of corrosive agents such as sulphuric acid, sulphur dioxide, sulphur dioxide and hydrogen iodide) and good thermal conductivity. The proposed method will provide almost pure silicon carbide products with multilayer laminate structure. Compared with other fabrication processes, this manufacturing approach for SiC-based ceramics has some advantages: the absence of secondary components (as is the case of bonded reaction infiltrated SiC) that expose the material to corrosion, easy-forming components, and a good toughness due to the laminate structure. The integration of porous layers in the multilayer structure as well as the integration of chopped carbon fibres, placed within the SiC sheets constituting the multilayer core, can provide better thermal management. Porous layers are suitable for lowering down the thermal conductivity through the thickness, while the fibres (aligned with the casting direction) are expected to increase the conductivity in the plane of the sheets and to drive the heat far from the hot spots. Finally both of them are suitable for improving the multilayer toughness, provided that suitable interfacial bonds between the layers as well as between the matrix and the fibres form. Toughness should be improved by exploiting de-bonding, pull-out and delamination phenomena, without decreasing too much the overall strength of the material. Then a compromise between strength and toughness should be achieved. Accordingly, three kinds of specimens were tested: · Multilayered SiC integrating porous layers, · Multilayered SiC integrating SiC and C long fibres layer. · Multilayered composites made by stacking Cf/SiC composite layers. Two kinds of chopped carbon fibres (polyamide coated and uncoated) were used for the manufacture of the composite sheets. Dense SiC was always used as a reference. The main concern in the design of ceramic laminates containing either porous layers or composite Cf/SiC layers deals with the risk of decreasing the oxidation resistance. In this research will be detailed the effects of different heat treatments (oxidation and/or corrosion) applied to different kinds of multilayer SiC. To this purpose the microstructure and the main mechanical properties will be compared before and after heat treatment.JRC.F.4-Safety of future nuclear reactor

EFECTIVIDAD DEL APOYO FAMILIAR EN EL CUMPLIMIENTO DEL TRATAMIENTO PARA REDUCIR ABANDONOS EN PACIENTES CON TUBERCULOSIS.

Trabajo AcadémicoMateriales y Métodos: Revisión Sistemática observacional y retrospectiva, la búsqueda se ha restringido a artículos con texto completo y los seleccionados se sometieron a una lectura crítica. Para el nivel de evidencia y la fuerza de recomendación se utilizó el Sistema Grade. Resultado: En la selección definitiva se eligieron 10 artículos, (20%) con dos articulos India, un artículo (10%) cada uno Perú, Colombia, Filipinas, Sudan, Africa, Iran, China y México. Han sido estudiados revisiones sistemáticas de Iran, India, Africa; seguido de estudios de casos y controles de Colombia, Filipinas, Perú y Sudan; estudios de cohorte de México y China; estudio cuasi experimental de India. El total de artículos analizados (100%) con un adecuado nivel de evidencia la relevancia que tiene el soporte que brinda la familia en el cumplimiento del tratamiento de la tuberculosis. Conclusión: Los diversos artículos estudiados a nivel nacional e internacional demuestran la efectividad que tiene el apoyo familiar en el cumplimiento del tratamiento para reducir abandonos en paciente con tuberculosis

Calidad total y gestión administrativa en la empresa Algarrobos Orgánicos del Perú SAC, Lima 2022

El presente estudio posee como objetivo general: Determinar la influencia entre la calidad total y la gestión administrativa en la empresa Algarrobos Orgánicos del Perú S.A.C. La metodología se basa en el enfoque cuantitativo, tipo aplicada, diseño no experimental, descriptivo y de corte transversal, método hipotético – deductivo y correlacional en una muestra conformada por 50 colaboradores y que mediante un cuestionario online se recopilaron datos relevantes para su análisis en SPSS v.25. En resultados, evidencia que el 82% de los trabajadores indicaron que la variable “calidad total” se presenta “alguna vez” en cada función dentro de la organización; y, en la variable “gestión administrativa” se precisa que el 98% señalaron que “algunas veces es adecuada. Finalmente, se afirma que existe una correlación negativa débil entre las variables “calidad total y gestión administrativa” a un nivel de significancia del 5% (0.05), siendo Rho de Spearman = -,319; asimismo, se rechaza la hipótesis nula y se acepta la hipótesis alterna, es decir, existe relación entre la calidad total y la gestión administrativa en la empresa Algarrobos Orgánicos del Perú S.A.C. – Lima – 2022

Estudio para la creación e implantación de un departamento de mercadeo en el hospital Mario Correa Rengifo

Trabajo de grado (Ingeniero Industrial)-- Universidad Autónoma de Occidente, 1996PregradoIngeniero(a) Industria