Fluvic acid carbon as a dignostic feature for agricultural soil evaluation

The fluvic acid fraction in considered to be sensitive to agronomic and environment factors. Therefore, the objectives of this study were to evaluate total carbon (TC) and fluvic acid carbon (FC) contens and to establish a possible relationship between the FC fraction and coarse organic matter in agricultural soils (CTVs), (ii) conservation tilled soils (CSTs), and (iii) virgins soils (VIRs) from a wide region in Argentina. The investigation includes 114 surface samples of Hapludolls, Haplustolls, and Entisols ranging in texture from sand to slit loam. In 29 selected samples, two separate soil mineral fraction were used (<0.05 mm and 0.1-2 mm) to determinate FC and TC contents. No statistically significant differences were found in TC contents in the fine fraction < 0.05 mm between VlRs, CSTs, and CVTs; however, FC contents were higher in VIRs than in CSTs and CVTs at the 0.05 probability level. In addition" statistically significant differences (P< 0.05) observed in FC contents among all three treatments in the coarse fraction 0.1-2 mm confirm that the FC fraction Is more influenced by the farming-system thn Is TC. Moreover, FC I TC ratios tended to increase under agricultural land use (CVTs > CSTs > VIRs), and this radio also Increased from finer textured soils to creaser tent was highly related to recently incorporated organic residues.Resúmenes de Trabajos presentados en otras publicaciones (por docentes de la UNLPam.) Publicado en Soil Science 1999; Vol 164: 57-6

Reconfigurable Boolean Logic using Magnetic Single-Electron Transistors

We propose a novel hybrid single-electron device for reprogrammable low-power logic operations, the magnetic single-electron transistor (MSET). The device consists of an aluminium single-electron transistors with a GaMnAs magnetic back-gate. Changing between different logic gate functions is realized by reorienting the magnetic moments of the magnetic layer which induce a voltage shift on the Coulomb blockade oscillations of the MSET. We show that we can arbitrarily reprogram the function of the device from an n-type SET for in-plane magnetization of the GaMnAs layer to p-type SET for out-of-plane magnetization orientation. Moreover, we demonstrate a set of reprogrammable Boolean gates and its logical complement at the single device level. Finally, we propose two sets of reconfigurable binary gates using combinations of two MSETs in a pull-down network

A hybrid double-dot in silicon

We report electrical measurements of a single arsenic dopant atom in the tunnel-barrier of a silicon SET. As well as performing electrical characterization of the individual dopant, we study series electrical transport through the dopant and SET. We measure the triple points of this hybrid double dot, using simulations to support our results, and show that we can tune the electrostatic coupling between the two sub-systems.Comment: 11 pages, 6 figure

Resonant tunneling spectroscopy of valley eigenstates on a donor-quantum dot coupled system

We report on electronic transport measurements through a silicon double quantum dot consisting of a donor and a quantum dot. Transport spectra show resonant tunneling peaks involving different valley states, which illustrate the valley splitting in a quantum dot on a Si/SiO2 interface. The detailed gate bias dependence of double dot transport allows a first direct observation of the valley splitting in the quantum dot, which is controllable between 160 and 240 μeV with an electric field dependence 1.2 ± 0.2 meV/(MV/m). A large valley splitting is an essential requirement for implementing a physical electron spin qubit in a silicon quantum dot

Torasemide inhibits angiotensin II-induced vasoconstriction and intracellular calcium increase in the aorta of spontaneously hypertensive rats

Torasemide is a loop diuretic that is effective at low once-daily doses in the treatment of arterial hypertension. Because its antihypertensive mechanism of action may not be based entirely on the elimination of salt and water from the body, a vasodilator effect of this drug can be considered. In the present study, the ability of different concentrations of torasemide to modify angiotensin II (Ang II)-induced vascular responses was examined, with the use of an organ bath system, in endothelium-denuded aortic rings from spontaneously hypertensive rats. Ang II-induced increases of intracellular free calcium concentration ([Ca(2+)](i)) were also examined by image analysis in cultured vascular smooth muscle cells (VSMCs) from spontaneously hypertensive rats. A dose-response curve to Ang II was plotted for cumulative concentrations (from 10(-9) to 10(-6) mol/L) in endothelium-denuded aortic rings (pD(2)=7.5+/-0.3). Isometric contraction induced by a submaximal concentration of Ang II (10(-7) mol/L) was reduced in a dose-dependent way by torasemide (IC(50)=0.5+/-0.04 micromol/L). Incubation of VSMCs with different concentrations of Ang II (from 10(-10) to 10(-6) mol/L) resulted in a dose-dependent rise of [Ca(2+)](i) (pD(2)=7.5+/-0.3). The stimulatory effect of [Ca(2+)](i) induced by a submaximal concentration of Ang II (10(-7) mol/L) was blocked by torasemide (IC(50)=0.5+/-0.3 nmol/L). Our findings suggest that torasemide blocks the vasoconstrictor action of Ang II in vitro. This action can be related to the ability of torasemide to block the increase of [Ca(2+)](i) induced by Ang II in VSMCs. It is proposed that these actions might be involved in the antihypertensive effect of torasemide observed in vivo

Graft Risk Index After Liver Transplant: Internal and External Validation of a New Spanish Indicator

OBJECTIVES: Scarcity of liver grafts has led to the use of marginal donors, consequently increasing the number of complications posttransplant. To prevent this situation, several indicators have been developed. However, important differences remain among countries. Here, we compared an early-risk liver transplant indicator based on the Spanish Liver Transplant Registry, called the Graft Risk Index, versus the US donor risk index and the Eurotransplant donor risk index. MATERIALS AND METHODS: The new indicator was based on prospectively collected data from 600 adult liver transplants performed in our center. We considered 2 events to compare the indexes: graft survival and rejection-free graft survival, with Cox proportional regression for analyses. Power to predict graft survival was evaluated by calculating the receiver operating characteristic area under the curve. RESULTS: We found no differences between the US and Eurotransplant donor risk indexes in prediction of patients with and without early graft failure. With regard to early survival, only the Graft Risk Index allowed better survival discrimination, in which survival progressively decreased with values = 3 (with probability of graft survival at 1 month of 68%; 95% confidence interval, 46.2-82.5). This increase in risk was significant compared with the standard group (hazard ratio of 10.15; 95% confidence interval, C 3.91- 26.32; P < .001). We calculated powers of prediction of 0.52 (95% confidence interval, 0.43-0.62), 0.54 (95% confidence interval, 0.45-0.65), and 0.69 (95% confidence interval, 0.61-0.77) for donor risk index, Eurotransplant donor risk index, and early Graft Risk Index, respectively. CONCLUSIONS: Neither the US donor risk index nor the Eurotransplant donor risk index was valid for our Spanish liver donation and transplant program. Therefore, an indicator to predict posttransplant graft survival that is adapted to our environment is necessary. This national Graft Risk Index can be a useful tool to optimize donor-recipient matchin

Instalación experimental para el estudio de sistemas zeoliticos de almacenamiento térmico

confieren un gran potencial comparado con el almacenamiento térmico sensible o latente [1]. El grupo GITSE de la Universidad de Zaragoza, basándose en los trabajos de [2] ha diseñado y construido dos instalaciones experimentales (escala de laboratorio) para estudiar el comportamiento térmico de sistemas de almacenamiento termoquímico. Los primeros estudios realizados se han llevado a cabo en un lecho fijo de zeolita empleando vapor de agua como pareja de trabajo. Se han realizado series de ensayos modificando algunos parámetros y variables relevantes (temperatura, humedad relativa, caudal de entrada, diámetro de partícula, altura del lecho ocupado). En la Fig. 1 se muestran los resultados de dos ensayos realizados empleando zeolita con diferente tamaño de partícula. La respuesta térmica del sistema (en términos de calor liberado, salto térmico y tiempo de respuesta), se ve fuertemente afectada por muchos de estos parámetros y variables, pero muestra un gran potencial y adaptabilidad para ser una tecnología útil para aprovechamiento de calores residuales.Los autores agradecen al Ministerio Español de Economía y Competitividad la financiación de este trabajo en el marco de los proyectos ENE2011-28269-C03-01 y ENE2011-22722 y la colaboración dentro del marco del Annex 29-Task 42 de la Agencia Internacional de la Energía. Finalmente, nuestro reconocimiento al Servicio General de Apoyo a la Investigación-SAI de la Universidad de Zaragoza

Glycine propionyl-L-carnitine increases plasma nitrate/nitrite in resistance trained men

We have recently demonstrated that oral intake of glycine propionyl-L-carnitine (GPLC) increases plasma nitrate/nitrite (NOx), a surrogate measure of nitric oxide production. However, these findings were observed at rest, and in previously sedentary subjects

Relationship between red blood cell transfusion requirements and severity of renal disease during the acute stage of hemolytic uremic syndrome

We performed a retrospective evaluation of patients with diarrhea-associated hemolytic uremic syndrome (D + HUS) with the aims of: (1) determining the rate of red blood cell (RBC) transfusions; (2) establishing the relationship between need for RBC transfusion and severity of renal involvement; (3) determining whether precise measurements of lactic dehydrogenase (LDH) levels can predict the rate of hemolysis and severity of renal disease. A total of 288 patients with D + HUS were retrospectively divided into three groups based on dialysis treatment: group 1, no dialysis treatment (144 patients); group 2, dialysis for 1–10 days (67 patients); group 3, dialysis for ≥11 days (77 patients). Of the patients in groups 1, 2 and 3, 73.6, 86.5 and 83.1 %, respectively, required at least one RBC transfusion. The number of RBC transfusions in groups 1, 2 and 3 was 163, 107 and 162, respectively. Comparison of the groups revealed that the number of RBC transfusions was significantly higher in patients in groups 2 and 3 than in those in group 1 (p = 0.0001). Most RBC transfusions (94.2 %) occurred during the first 2 weeks of the disease. The median peak LDH level was 2091 U/l in 32 patients with no RBC transfusion (group A), 3900 U/l in 73 patients with one transfusion (group B) and 6378 U/l in 62 patients with two or more transfusions (group C). Patients who received two or more RBC transfusions had a significantly higher median peak LDH level than those who did not receive RBC transfusions or received only one transfusion. This difference was also observed between patients who received only one RBC transfusion and those who did not receive any transfusions (p  10 days of dialysis (group 3) had the highest LDH levels, followed by patients with 1–10 days of dialysis (group 2) and then by patients with no dialysis requirements (group 1) (p < 0.00001). The rate of RBC transfusion was higher in patients with the most severe renal injury, and most were performed during the first 2 weeks of the disease. Patients with stable LDH levels seemed to require fewer RBC transfusions. Median peak LDH levels were significantly higher in the group of patients with the most severe renal disease.Facultad de Ciencias Veterinaria