989 research outputs found

    Quantification of microstructural changes during first stage air drying of grape tissue

    Get PDF
    Microstructural changes in cells of Ruby grape (Vitis vinifera) quarters were monitored during first stage of convective air drying, under a stereo-microscope. A gradual overall shrinkage of grape cells was observed during the process. The cellular parameters: area, perimeter, major and minor axis length, Feret diameter, elongation, roundness and compactness, were quantified by image analysis. It was verified that cell dimensions suffered modifications during drying, but their shape remained unchanged. These microstructural changes showed a smooth exponential decrease with time, and a first-order kinetic model was satisfactorily fitted to the data. Temperature increased the rate of cellular shrinkage and this effect followed an Arrhenius type behaviour. Increasing temperature from 20 to 60 C resulted in a 350% increase of the area change rate. For the parameters related to cellular dimensions, the magnitude of the values were 10 3 min 1 for the rate of change at 40 C and 3 kJ/mol for the activation energ

    Comparative study of risk factors among children and adolescents with an anthropometric diagnosis of overweight or obesity

    Get PDF
    OBJETIVO: O excesso de peso é um grande problema de saúde pública em todo o mundo, atingindo crianças e adolescentes. O presente estudo teve por objetivo verificar se a condição de portador de sobrepeso se associa à presença de fatores de risco à saúde. MÉTODOS: Foram estudados 84 sujeitos entre seis e 17 anos, constituindo-se um grupo de 34 pacientes portadores de sobrepeso e outro de 50 obesos, atendidos em ambulatório de Nutrologia Pediátrica da Universidade de Ribeirão Preto (Unaerp), durante o período de outubro de 2004 a outubro de 2005. Foram obtidas as variáveis: pressão arterial, circunferência abdominal, glicemia de jejum, glicemia de segunda hora, colesterol total, HDL-c, LDL-c e triglicérides. Comparam-se os dois grupos por meio de duas abordagens estatísticas: comparação entre as distribuições dos valores absolutos (teste de Mann-Whitney) e entre as frequências de valores considerados alterados (teste exato de Fisher). RESULTADOS: Quanto à primeira abordagem, verificou-se diferença estatística apenas para o HDL-c, com maiores valores para o subgrupo de portadores de sobrepeso de seis a dez anos. Quanto à segunda comparação, verificou-se diferença estatística para a circunferência abdominal (segundo os critérios de Freedman), HDL-c e glicemia de jejum, com maiores frequências de valores alterados entre os obesos. CONCLUSÕES: Os portadores de sobrepeso apresentaram alterações indicativas de prejuízos à sua saúde, semelhantemente aos obesos, sendo necessário também incluí-los nos programas de prevenção e tratamento.OBJECTIVE: Excess weight is a serious public health problem all over the world, affecting children and adolescents. The objective of the present study was to determine whether the condition of being overweight is associated to changes in health parameters. METHODS: 84 subjects aged 6-17 years old were studied (34 overweight and 50 obese patients), all of them assisted at the Pediatric Nutrology outpatient clinic of the University of Ribeirão Preto (Unaerp) from October/2004 to October/2005. Arterial pressure, abdominal circumference, fast glycemia, second hour glycemia, total cholesterol and its fractions (HDL-c and LDL-c) and triglycerides were determined. The two groups were compared by two statistical approaches: comparison of absolute values by Mann-Whitney test, and between frequencies of altered values by Fisher exact test. RESULTS: There was a statistical difference only for HDL-c, with higher concentrations in the overweight group when the subgroup of patients with 6-10 years old was considered. Regarding the second approach, there were statistical differences in the abdominal circumference by Freedman criteria, HDL-c and fast glycemia, with higher frequencies of altered values among obese subjects. CONCLUSIONS: Overweight patients presented alterations harmful to their health, similarly to obese individuals. It is necessary to enroll overweight children and adolescents in programs dedicated to the prevention and treatment of nutritional problems

    Histological Study of Fresh Versus Frozen Semitendinous Muscle Tendon Allografts

    Get PDF
    OBJECTIVE: The purpose of this study was to histologically analyze allografts from cadaveric semitendinous muscle after cryopreservation at -80°C in comparison to a control group kept at only -4°C to test the hypothesis that the histological characteristics of the tissue are maintained when the tendons are kept at lower temperatures. METHODS: In a tissue bank, 10 semitendinous tendons from 10 cadavers were frozen at -80ºC as a storage method for tissue preservation. They were kept frozen for 40 days, and then a histological study was carried out. Another 10 tendon samples were analyzed while still "fresh". RESULTS: There was no histological difference between the fresh and frozen samples in relation to seven variables. CONCLUSIONS: Semitendinous muscle tendon allografts can be submitted to cryopreservation at -80ºC without suffering histological modifications

    Caracterización geoquímica de los residuos mineros y aguas superficiales de la mina abandonada Jornune (Lampa Mining)

    Get PDF
    El presente artículo tiene por objetivo analizar la geoquímica de los residuos mineros de la mina abandonada Jornune (Lampa Mining), ubicado en el distrito de Cabanillas, provincia de Lampa, en la región de Puno. Para tal objetivo se tomaron muestras de agua superficial, agua subterránea, residuos mineros, sedimentos de río y precipitados en un manantial de la zona en contacto con el residuo minero, de los cuales se determinaron las concentraciones químicas de los siguientes elementos químicos: Ag, Al, As, Ba, Be, Cd, Co, Cr, Cu, Fe, Hg, Mn, Mo, Ni, Pb, Sb, Se, Th, Tl, U, V y Zn

    Comparación de modelos unicarácter y multicarácter para estimar componentes de (Co) varianza y parámetros genéticos del crecimiento en la raza bovina Costeño con Cuernos

    Get PDF
    The study aimed to estimate the components of (co) variance and genetic parameters for growth traits as birth weight (BW), weaning weight (WW) and weight at 16 months of age (W16) of calves of the creole breed Costeño con Cuernos, born between 1989 and 2011 in a herd located in the northeast of Colombia. For this, 3060, 2594 and 1990 BW, WW and W16 records were analyzed, respectively. Single-trait (UNI) and multi-trait (MT) models were used. Six variants were evaluated with the UNI model, in all cases the random effect of the animal was included and the rest of the models alternated the maternal effect, the effect of the permanent environment and the relationship between the direct and maternal effect. Goodness of fit was determined using the information criteria of Akaike (AIC), Bayesiana (BIC) and LogL. For BW and WW models involving direct, maternal, and permanent maternal environment effects showed the best fit, and for W16 the best fit model was the one that only considered the direct effect. The heritability values of the UNI and MT models were similar for BW (0.14 and 0.16, respectively). For WW and W16, the MT model, in relation to the UNI, increased h2a by 42% (0.27 vs. 0.19; 0.31 vs. 0.21, respectively), as well as h2T for WW by 34% (0.31 vs. 0.23). The genetic variability found allows the application of a selection process and it is recommended to use the multi-trait models for the genetic evaluation of the herd.Con el objetivo de estimar los componentes de (co)varianza y parámetros genéticos para los rasgos de crecimiento peso al nacer (PN), al destete (PD) y 16 meses de edad (P16) de terneros de la raza bovina Costeño con Cuernos, nacidos entre 1989 y 2011 en un rebaño ubicado en el nordeste de Colombia, se analizaron 3060, 2594 y 1990 registros de PN, PD y P16, respectivamente. Se utilizaron modelos unicarácter (UNI) y multicarácter (MT). Con el modelo UNI se evaluaron seis variantes, en todos los casos se incluyó el efecto aleatorio del animal y el resto de los modelos alternaron el efecto materno, el efecto del ambiente permanente y la relación entre el efecto directo y materno. La bondad de ajuste se determinó con los criterios de información de Akaike (AIC), Bayesiana (BIC) y LogL. Se encontró que para PN y PD los modelos que involucran los efectos directos, maternos y de ambiente permanente materno fueron los de mejor ajuste, y para P16 el modelo que solo tuvo en cuenta el efecto directo. Los valores de la heredabilidad de los modelos UNI y MT fueron similares en PN 0.14 y 0.16, respectivamente. Para PD y P16, el modelo MT, en relación con el UNI, incrementó la h2a en un 42% (0.27 vs 0.19; 0.31 vs 0.21, respectivamente), así como la h2T para PD en un 34% (0.31 vs 0.23). La variabilidad genética encontrada posibilita la aplicación de un proceso de selección y se recomienda utilizar los modelos multicarácter para la evaluación genética del hato

    An?lisis y propuesta de mejora del m?todo de contrataci?n de acuerdo marco del sistema de contrataciones del Estado, en el Per?

    Get PDF
    En el Per?, del total de las contrataciones p?blicas del a?o 2016, el 82,7 % se realizaron bajo el r?gimen general de procedimientos cl?sicos, un 13,7% se realizaron por otros reg?menes de contrataci?n, y s?lo el 3,6 % se ejecutaron a trav?s del m?todo especial de contrataci?n de Acuerdo Marco. Los procedimientos cl?sicos demandan mayores recursos, en cuanto a tiempos para la contrataci?n de bienes o servicios (hasta 42 d?as h?biles), y mayores costos en la gesti?n administrativa (log?sticos, recursos humanos, financieros); a diferencia del Acuerdo Marco cuyo proceso de contrataci?n tiene una duraci?n m?xima de 5 d?as h?biles, con su uso permite la optimizaci?n de los recursos del Estado, sin embargo hasta ahora no se ha desarrollado eficientemente como en otros pa?ses, Por ello, la importancia de su estudio y propuesta de mejora, a fin de que el m?todo especial de contrataci?n se desarrolle m?s, y les permitan a las entidades p?blicas ejecutar sus contrataciones oportunamente a trav?s de los Cat?logos Electr?nicos, contribuyendo a disminuir los costos administrativos, ahorro en el tiempo del proceso, fomentar la competencia y reducir la discrecionalidad, mejorando la transparencia. Todo ello, redundar? en maximizar la utilizaci?n de los recursos p?blicos beneficiando a los ciudadanos

    Oxidative Stress and Cellular Senescence Are Involved in the Aging Kidney

    Full text link
    Chronic kidney disease (CKD) can be considered as a clinical model for premature aging. However, non‐invasive biomarkers to detect early kidney damage and the onset of a senescent phenotype are lacking. Most of the preclinical senescence studies in aging have been done in very old mice. Furthermore, the precise characterization and over-time development of age-related senes-cence in the kidney remain unclear. To address these limitations, the age-related activation of cellular senescence-associated mechanisms and their correlation with early structural changes in the kidney were investigated in 3- to 18-month-old C57BL6 mice. Inflammatory cell infiltration was ob-served by 12 months, whereas tubular damage and collagen accumulation occurred later. Early activation of cellular-senescence-associated mechanisms was found in 12-month-old mice, character-ized by activation of the DNA-damage-response (DDR), mainly in tubular cells; activation of the antioxidant NRF2 pathway; and klotho downregulation. However, induction of tubular-cell-cycle-arrest (CCA) and overexpression of renal senescent-associated secretory phenotype (SASP) components was only found in 18-month-old mice. In aging mice, both inflammation and oxidative stress (marked by elevated lipid peroxidation and NRF2 inactivation) remained increased. These findings support the hypothesis that prolonged DDR and CCA, loss of nephroprotective factors (klotho), and dysfunctional redox regulatory mechanisms (NRF2/antioxidant defense) can be early drivers of age-related kidney-damage progressionThis research was funded by grants from the Instituto de Salud Carlos III (ISCIII); Fondos FEDER European Union (PI17/00119, PI20/00140; and DTS20/00083 to M.R.-O.; PI18/01133 to A.M.R.); Sara Borrell’ program from Instituto de Salud Carlos III (ISCIII) (grant number CD20/00042 to R.R.R.-D.); Red de Investigación Renal REDINREN: RD16/0009/0003 and RICORS program to RICORS2040 496 (RD21/0005), to M.R.-O., Sociedad Española de Nefrología; “NOVELREN-CM: Enfermedad renal crónica: nuevas Estrategias para la prevención, Diagnóstico y tratamiento” (B2017/BMD3751 to M.R.-O.); “Convocatoria Dinamización Europa Investigación 2019” MINECO (EIN2019-103294 to M.R.-O.); Juan de la Cierva incorporacion grant: IJC2018-035187-I to S.R.-M.; innovation program under the Marie Skłodowska-Curie grant of the European Union’s Horizon 2020 (IMProvePD ID: 812699) to M.R.-O.; and Fundacion Conchita Rabago to L.T.-
    corecore