2,828 research outputs found
OPTIMIZACIÓN DEL MEDIO PARA LA PRODUCCIÓN DE PROTEASAS EXTRACELULARES POR Pseudomonas sp. M211 EN FERMENTACIÓN SUMERGIDA
Las proteasas microbianas representan el grupo más destacado en el mercado mundial de enzimas, ya que tienen diversas aplicaciones industriales. Además, poseen ventajas respecto a las producidas por otras fuentes, tales como ser más estables y ser excretadas al medio de fermentación. El género Pseudomonas ha sido reportado como productor de proteasas con potencial industrial. Sin embargo, en la producción intervienen factores como la composición del medio y las condiciones de cultivo, cuya optimización permite reducir costos e incrementar el rendimiento. En este contexto, se determinaron los componentes del medio que influyeron significativamente en la producción de proteasas extracelulares por Pseudomonas sp. M211 en fermentación sumergida. El estudio de un factor a la vez permitió evaluar el efecto de diferentes fuentes de carbono, nitrógeno y de iones en la producción. Los valores más altos se obtuvieron usando las fuentes de carbono: glicerol, maltosa, galactosa o glucosa; las de nitrógeno: peptona, extracto de carne, extracto de levadura o NH4 Cl; y las de iones: CaCl2 o KCl. Estos factores fueron seleccionados para elaborar el diseño experimental Plackett-Burman. Los factores se evaluaron en dos niveles, alto (+1) y bajo (-1), y cinco puntos centrales, para lo cual se realizaron 33 experimentos con una réplica. Del análisis, se determinó que los factores extracto de levadura y peptona influyeron significativamente (p < 0, 05) en la producción
Evaluación de la microdureza de cementos resinosos de uso odontológico: estudio in vitro
OBJETIVO: Es importante conocer las propiedades mecánicas de los materiales dentales para poder determinar críticamente su comportamiento y no limitarnos únicamente a la evaluación clínica. Por esa razón, el objetivo de este estudio fue comparar la microdureza de cuatro cementos resinosos de uso odontológico teniendo en cuenta que existe correlación entre esta propiedad mecánica y el comportamiento clínico del material.MATERIALES Y MÉTODOS: Se confeccionaron seis cuerpos de prueba para cada cemento evaluado: RelyXTM ARC(3M ESPE) = G1, Multilink® (IVOCLAR VIVADENT) = G2, MaxCem EliteTM (KERR CORPORATION) = G3 y RelyXTMU200 (3M ESPE) = G4, los que fueron almacenados durante 48 horas a temperatura ambiente y sometidos al ensayo deMicrodureza Vickers (VMH) con 200 g-f durante 10 segundos.RESULTADOS: Para el cemento resinoso dual convencional (grupo control) G1 el valor promedio de microdureza fue47.08 ± 4.52 VMH. El cemento resinoso dual de autograbado (G2) tuvo un valor promedio de 43.88 ± 2.35 VMH. Elvalor promedio de microdureza del cemento resinoso autoadhesivo G3 fue de 37.41 ± 3.10 VMH mientras que para elcemento resinoso autoadhesivo G4 se obtuvo un valor promedio de 50.58 ± 1.10 VMH.CONCLUSIÓN: Se concluye que el cemento resinoso autoadhesivo dual RelyXTM U200 presentaría un mejor comportamiento clínico ya que los valores de microdureza encontrados fueron los más altos, encontrando diferencias estadísticamente significativas con Multilink® y MaxCem EliteTM
Infants exposed in utero to Hurricane Maria have gut microbiomes with reduced diversity and altered metabolic capacity
The gut microbiome is a potentially important mechanism that links prenatal disaster exposures with increased disease risks. However, whether prenatal disaster exposures are associated with alterations in the infant\u27s gut microbiome remains unknown. We established a birth cohort study named Hurricane as the Origin of Later Alterations in Microbiome (HOLA) after Hurricane Maria struck Puerto Rico in 2017. We enrolled vaginally born Latino term infants aged 2 to 6 months, includin
Erythropoietin (EPO) increases myelin gene expression in CG4 oligodendrocyte cells through the classical EPO receptor
Erythropoietin (EPO) has protective effects in neurodegenerative and neuroinflammatory diseases, including in animal models of multiple sclerosis, where EPO decreases disease severity. EPO also promotes neurogenesis and is protective in models of toxic demyelination. In this study, we asked whether EPO could promote neurorepair by also inducing remyelination. In addition, we investigated whether the effect of EPO could be mediated by the classical erythropoietic EPO receptor (EPOR), since it is still questioned if EPOR is functional in non-hematopoietic cells. Using CG4 cells, a line of rat oligodendrocyte precursor cells, we found that EPO increases the expression of myelin genes (myelin oligodendrocyte glycoprotein (MOG) and myelin basic protein (MBP)). EPO had no effect in wild-type CG4 cells, which do not express EPOR, whereas it increased MOG and MBP expression in cells engineered to overexpress EPOR (CG4-EPOR). This was reflected in a marked increase in MOG protein levels, as detected by western blot. In these cells, EPO induced by 10-fold the early growth response gene 2 (Egr2), which is required for peripheral myelination. However, Egr2 silencing with a siRNA did not reverse the effect of EPO, indicating that EPO acts through other pathways. In conclusion, EPO induces the expression of myelin genes in oligodendrocytes and this effect requires the presence of EPOR. This study demonstrates that EPOR can mediate neuroreparative effects
Ipsilateral vagotomy to unilaterally ovariectomized pre-pubertal rats modifies compensatory ovarian responses
The present study evaluates the participation of the vagus nerve in pre-pubertal rats with unilateral ovariectomy on puberty onset, and on progesterone, testosterone and estradiol serum levels, and the compensatory responses of the ovary. Unilateral vagotomy did not modify the onset of puberty in unilaterally ovariectomized rats. Ovulation rates of animals with the left vagus nerve sectioned and the left ovary in-situ was lower than in rats with only unilateral ovariectomy. Sectioning the left vagus to 32-day old rats with the left ovary in-situ resulted in lower compensatory ovarian hypertrophy than in rats with right unilateral ovariectomy. Twenty-eight or 32-day old animals with sectioning of the right vagus nerve and the right ovary in situ showed higher compensatory ovulation. Twenty-eight -day old rats with the right ovary in situ had higher progesterone and testosterone levels than animals of the same age with the left ovary in-situ. Compared to animals with the right ovary in situ, animals treated at 32-days of age, sectioning the ipsi-lateral vagus nerve resulted in higher progesterone levels. Higher progesterone levels were observed in 28- and 32 days old rats with the left ovary in situ and left vagus nerve sectioned. Thirty-two day old animals with the right ovary in situ and right vagus nerve sectioned had higher progesterone levels than rats of the same age with the left ovary in situ and left vagus nerve sectioned. Left vagotomy to 28-day old rats with the left ovary in situ resulted in higher testosterone levels, a reverse response to that observed in animals with sectioning of the right vagus and the right ovary in situ. Thirty-two day old rats with the left ovary in situ and left vagus nerve sectioned showed lower testosterone levels than animals without vagotomy and with the left ovary in situ
The role of the muscarinic system in regulating estradiol secretion varies during the estrous cycle: the hemiovariectomized rat model
There is evidence that one gonad has functional predominance. The present study analyzed the acute effects of unilateral ovariectomy (ULO) and blocking the cholinergic system, by injecting atropine sulfate (ATR), on estradiol (E(2)) serum concentrations during the estrous cycle. The results indicate that ULO effects on E(2 )concentrations are asymmetric, vary during the estrous cycle, and partially depend on the cholinergic innervation. Perforation of the left peritoneum resulted in lower E(2 )serum concentrations in the three stages of the estrous cycle. At proestrus, unilateral or bilateral perforation of the peritoneum resulted in lower E(2 )serum concentrations. ULO of the right ovary (left ovary in situ) resulted in significantly higher E(2 )concentrations than animals with ULO of the left ovary (right ovary in situ). ATR treatment to ULO rats on D1 resulted in a significant drop of E(2 )serum concentrations. ULO rats treated with ATR on D2 or P, resulted in an asymmetrical E(2) secretion response; when the right ovary remained in situ an increase in E(2) was observed, and a decrease when the left ovary remained in situ. The results obtained in the present study suggest that each ovary's ability to compensate the secretion of E(2 )from the missing ovary is different and varies during the estrous cycle. The results also suggest that the cholinergic system participates in regulating ovarian E(2 )secretion. Such participation varies according to the ovary remaining in situ and the stage of the estrous cycle of the animal. The results agree with previously stated hypothesis of a neural pathway arising from the peritoneum that participates in regulating E(2 )secretion, and also supports the idea of cross-talk between the ovaries, via a neural communication, that modulates E(2 )secretion
Utilización de la yoga en la mejora del peso corporal y flujo pico espiratorio de personas con sobrepeso y obesidad
The present investigation is of the quasi-experimental type of temporal series design interrupted with a group with repeated measures of pretest and posttest. The objective of the same was the evaluation of a Yoga training program on the effects on the Peak Expiratory Flow (PEF) and on overweight-obesity of female patients who attended the Mutual Aid Groups of the Secretary of Health in Manzanillo, Mexico. The intervention group consisted of 15 women with an average age of 46 years (16) without chronic non-communicable diseases, the program was designed for 6 with two weekly sessions of 40 minutes each (80 min per week). The instruments used to verify the progress in the PEF and the BMI are: clinical history, portable flowmeters and a minimum protocol of weight and height Quetelet´s formula to determine the BMI, as well as an interview at the end of the intervention to know aspects about participation in the intervention. Among the main findings, there was a significant progress in Peak Expiratory Flow (PEF) after the intervention, the participants were able to make a deeper inhalation and a greater exhalation. The results show positive effects on the PEF after a 6-week program with specific yoga work to improve breathing, but not for BMI and changes in body weight.
La presente investigación es de tipo cuasiexperimental de diseño serie temporal interrumpida con un grupo con medidas repetidas de pretest y postest. El objetivodel mismo, fue la evaluación de un programa de entrenamiento de Yoga sobre los efectosen elFlujo Pico Espiratorio (PEF) yen sobrepeso-obesidad de pacientes femeninos que asistieron a los Grupos de Ayuda Mutua de la Secretaria de Salud en Manzanillo, México. El grupo de intervención estuvo integrado por 15 mujeres con un promedio de edad de 46 años (±16) sin enfermedades crónicas no transmisibles, el programa se diseñó para 6 semanas con dos sesiones semanales de 40 minutos cada una (80 min por semana). Los instrumentos utilizados para verificar el progreso en el PEF e IMC fueron,historia clínica, flujometros portátiles y un protocolo mínimo de toma de peso y talla y la fórmula de Quetelet para determinar el IMC, así como, una entrevista al final de la intervención para conocer aspectos sobre la participación en la intervención. Entre los principales hallazgos se evidencia un progreso significativo en Flujo Pico Espiratorio (PEF) posterior a la intervención, las participantes fueron capaces de hacer una inspiración más profunda y una espiración mayor. Los resultados muestran efectos positivos en el PEF posterior a un programa de 6 semanas con trabajo de yoga específico para la mejora de respiración, pero no para disminución de IMC y cambios en el peso corporal
Reaction rates and transport in neutron stars
Understanding signals from neutron stars requires knowledge about the
transport inside the star. We review the transport properties and the
underlying reaction rates of dense hadronic and quark matter in the crust and
the core of neutron stars and point out open problems and future directions.Comment: 74 pages; commissioned for the book "Physics and Astrophysics of
Neutron Stars", NewCompStar COST Action MP1304; version 3: minor changes,
references updated, overview graphic added in the introduction, improvements
in Sec IV.A.
English Language Proficiency and Geographical Proximity to a Safety Net Clinic as a Predictor of Health Care Access
Studies suggest that proximity to a safety net clinic (SNC) promotes access to care among the uninsured. Distance-based barriers to care may be greater for people with limited English proficiency (LEP), compared to those who are English proficient (EP), but this has not been explored. We assessed the relationship between distance to the nearest SNC and access in non-rural uninsured adults in California, and examined whether this relationship differs by language proficiency. Using the 2005 California Health Interview Survey and a list we compiled of California’s SNCs, we calculated distance between uninsured interviewee residence and the exact address of the nearest SNC. Using multivariate regression to adjust for other relevant characteristics, we examined associations between this distance and interviewee’s probability of having a usual source of health care (USOC) and having visited a physician in the prior 12 months. To examine differences by language proficiency, we included interactions between distance and language proficiency. Uninsured LEP adults living within 2 miles of a SNC were 9.3% less likely than their EP counterparts to have a USOC (P = 0.046). Further, distance to the nearest SNC was inversely associated with the probability of having a USOC among LEP, but not among EP; consequently, the difference between LEP and EP in the probability of having a USOC widened with increasing distance to the nearest SNC. There was no difference between LEP and EP adults living within 2 miles of a SNC in likelihood of having a physician visit; however, as with USOC, distance to the nearest SNC was inversely associated with the probability of having a physician visit among LEP but not EP. The effect sizes diminished, but remained significant, when we included county fixed effects in the models. Having LEP is a barrier to health care access, which compounds when combined with increased distance to the nearest SNC, among uninsured adults. Future studies should explore potential mechanisms so that appropriate interventions can be implemented
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