Speed of sound measurements of two binary natural gas mixtures (methane plus n-butane and methane plus isopentane) at cryogenic temperatures and in liquid phase

This paper presents accurate speed of sound measurements in two specific single-phase liquefied natural gas mixtures (methane + isopentane and methane +n-butane) for temperatures ranging from (100 to 160) K and pressures up to 12 MPa, with expanded relative uncertainties (k = 2) between (0.27 and 0.35) % for methane + n-butane and between (0.26 and 0.30) % for the methane + isopentane. These measurements have been obtained using the double pulse-echo technique. The experimental results of these measurements were compared with the values predicted by the GERG-2008 model and the most recent fundamental equation of state for the calculation of thermodynamic properties of liquefied natural gases, EOS-LNG

Speed of sound measurements in deuterium oxide (D 2 O) at temperatures between (276.97 and 363.15) K and at pressures up to 210 MPa

partially_open3embargoed_20211119Lago Simona, Giuliano Albo Paolo Alberto, Cavuoto GiuseppeLago, Simona; GIULIANO ALBO, PAOLO ALBERTO; Cavuoto, Giusepp

Speed of sound measurements in deuterium oxide (D2O) at temperatures between (276.97 and 363.15) K and at pressures up to 210 MPa

This paper presents speed of sound measurements in heavy water (deuterium oxide, ) along six isotherms between 276.97 K and 363.15 K for pressures up to 210 MPa using a double pulse-echo method. The experimental apparatus was validated measuring the speed of sound in ordinary water at ambient pressure and at temperatures between 295.5 K and 363.15 K with results found in agreement with values calculated from the reference equation of state for water by Wagner and Pruß within 0.005%. The relative combined expanded uncertainty of our speed of sound measurements, at a confidence level of 95%, is estimated to be less than 0.03% for pressures up to 10 MPa and in the order of 0.05% for pressures up to 210 MPa in the whole investigated temperature range. The speed of sound results have been compared with values calculated from the reference equation for heavy water the IAPS84 Formulation by Hill et al. (1982), and with the prediction of the newly developed equation of state for heavy water by Herrig et al. (2018). The relative deviations of these comparison were found to be consistent with the reference equations within their combined uncertainty. The results presented here were also compared with the most recent data by Wegge et al. and found to be in agreement within 0.05%

The Rosenberg Self-Esteem Scale: Translation and Validation in University Students

El propósito de esta investigación ha sido traducir al español y analizar las propiedades psicométricas de la escala de autoestima de Rosenberg (RSES) en una muestra de estudiantes universitarios. El análisis factorial confirmatorio confirmó que el modelo que mejor se ajusta a los datos tanto en la muestra total como en las submuestras de hombres y mujeres tiene una estructura unifactorial con efectos de método en los ítems formulados en positivo. Los resultados indican correlaciones positivas y fuertes entre la autoestima y cinco dimensiones del autoconcepto. Además, la escala ha mostrado niveles satisfactorios de consistencia interna y estabilidad temporal tras un periodo de cuatro semanas. Finalmente, se han obtenido diferencias de género significativas. Estos resultados apoyan el uso de la RSES para evaluar la autoestima en el contexto educativo universitario.The aim of this study was to translate into Spanish and to validate the Rosenberg Self-Esteem Scale (RSES), completed by 420 university students. Confirmatory factor analysis revealed that the model that best fit the data, both in the total sample and in the male and female subsamples, was the one-factor structure with method effects associated with positively worded items. The results indicated high, positive correlations between self-esteem and the five dimensions of selfconcept. The scale showed satisfactory levels of internal consistency and temporal stability over a four-week period. Lastly, gender differences were obtained. These findings support the use of the RSES for the assessment of self-esteem in higher education

Estudio del nivel tecnológico del productor apícola: una herramienta para mejorar la competitividad del sector.

Unos de los aspectos importantes en la planificación de la producción es conocer el nivel tecnológico del productor apícola, propósito de evaluar el nivel de competitividad y las mejoras que se deben realizar en los diferentes eslabones de la producción. Con un Plan de Desarrollo Apícola y en el accionar de los Servicios de Extensión, es importante establecer un método para evaluar el nivel de capacitación del apicultor, conocer el resultado de sus actividades, los aciertos y errores. Se deben identificar las líneas estratégicas que deben atenderse con prioridad. En este sentido, los objetivos del presente trabajo fueron determinar dentro de la cadena productiva apícola el “Nivel Tecnológico del Apicultor del partido de Magdalena”. Se visitó a un tercio del total de los productores apícolas del partido inscriptos en el Registro de Marcas de la Provincia de Buenos Aires. Se elaboró y realizó una Encuesta para determinar el Nivel Tecnológico del apicultor, cuya puntuación se definió en forma proporcional a la importancia, desde el punto de vista técnico, de la práctica de manejo apícola. Se efectuaron visitas a los apiarios y un informe complementario a la encuesta, donde se volcaron otros datos proporcionados por los productores. Los resultados indicaron que el 4.5, 27, 64 y 4.5% de los apicultorescorrespondían a las categorías “Aceptable”, “Buena”, “Muy buena” y “Excelente”, respectivamente. Asimismo, no se observaron apicultores con nivel “Regular”. Con respecto a los problemas de mayor incidencia fueron identificados como de primer orden: el precio de la miel, falta de mano de obra, los colmenares abandonados como foco de contagio de enfermedades y la ausencia de una presión política de apoyo a la actividad apícola. Se consideraron de segundo orden: el escaso campo natural, falta de apoyo al sector, los problemas económicos, falta de aviso en las pulverizaciones, precios de la miel inestables, elevados costos de los insumos, burocracia administrativa para la habilitación de plantas de extracción; falta de capacitación superior, por ejemplo, tecnicaturas. Finalmente, los de tercer orden fueron: la falta de información sobre producciones alternativas, problemas de comercialización, sanidad, manejo, mercado, legislación y asociativismo. De todo lo expuesto, se destacan que los aspectos de mayor relevancia son las deficiencias en el manejo de la alimentación de la colonia en otoño – invierno y en primavera, los registros y la renovación de cuadros.publishedVersio

Tumour cell thrombospondin-1 regulates tumour cell adhesion and invasion through the urokinase plasminogen activator receptor

We have previously shown that platelet-produced thrombospondin-1 up-regulates the urokinase plasminogen activator and its receptor and promotes tumour cell invasion. Although tumour cells produce thrombospondin-1 in vivo, they produce only minimal amounts of thrombospondin-1 in vitro. To determine the effect of tumour cell-produced thrombospondin-1 in the regulation of the plasminogen/plasmin system and tumour cell invasion, we studied THBS-1 -transfected MDA-MB-435 breast cancer cells that overexpress thrombospondin-1. The role of urokinase plasminogen receptor in thrombospondin-1-mediated adhesion and invasion was studied by antisense inhibition, enzymatic cleavage and antibody neutralization. Tumour cell adhesion to collagen and laminin was evaluated. Tumour cell invasion was studied in a modified Boyden chamber collagen invasion assay. Tumour cell thrombospondin-1 induced a 2–7 fold increase in urokinase plasminogen activator receptor and cell-associated urokinase plasminogen activator expression and a 50–65% increase in cell-associated urokinase plasminogen activator and plasmin activities. Furthermore, tumour cell thrombospondin-1 promoted tumour cell invasion and decreased tumour cell adhesion through up-regulation of urokinase plasminogen activator receptor-controlled urokinase plasminogen activator and plasmin activities. We conclude that tumour cell-produced thrombospondin-1 may play a critical role in the regulation of tumour cell adhesion and tumour cell invasion. © 2000 Cancer Research Campaig

Metachronous bladder metastases from renal cell carcinoma: a case report and review of the literature

INTRODUCTION: adrenal gland, parotid gland, pharynx, eye and bladder are rare localizations of metastases of renal cell carcinoma (RCC). We report a case of metachronous RCC metastases to the bladder in a patient with a medical history of transitional cell carcinoma (TCC) of the bladder. MATERIALS AND METHODS: a case study and review of the relevant literature are presented. RESULTS: during a follow-up cystoscopy examination following treatment of TCC, a single 5-mm lesion was detected and endoscopically resected. The histology of the resected sample was confirmed to be RCC, comparable to a primary kidney cancer and not recurrent TCC. CONCLUSION: the patient had a probability of metastases three years after nephrectomy of 62.9%. Survival rates following single metastasectomy are 60% and 38% at three and five years, respectively; metachronous diagnosis has a better prognosis than synchronous. During RCC follow-up, each lesion should be considered as a possible metastasis of RCC