Héctor Fasoli

Exposure to zinc deficiency in fetal and postnatal life determines nitric oxide system activity and arterial blood pressure levels in adult rats

We had previously shown that prenatal exposure to Zn-deficient diets induces an increase in blood pressure and impairs renal function in adult rats. The aim of the present study was to investigate if moderate Zn restriction during early growth periods, fetal life and lactation would induce impairment in the vascular and renal NO system and alterations in plasma lipid profile. We also investigated if these effects persisted into adult life, even when a Zn-replete diet was provided after weaning. Pregnant rats were fed control (30 parts per million (ppm)) or low (8 ppm) Zn diets throughout gestation up to weaning. Afterwards, male offspring from low-Zn mothers were assigned to low- or control-Zn diets during 60 d. Male offspring from control mothers were fed a control diet. Animals exposed to Zn restriction showed low birth weight, increased systolic blood pressure and serum TAG levels, and decreased glomerular filtration rate in adulthood. Zn restriction induced a decrease in vascular and renal NO synthase activity and a reduced expression of the endothelial NO synthase isoform in aorta. A control-Zn diet during post-weaning growth returned TAG levels to normal but was unsuccessful in normalising systolic blood pressure, glomerular filtration rate or NO system activity in Zn-deficient offspring. Zn restriction during fetal life, lactation and/or post-weaning growth induced alterations in the vascular and renal NO system and in lipid metabolism that could contribute to the programming of hypertension and renal dysfunction in adulthood.

Mild zinc deficiency in male and female rats: Early postnatal alterations in renal nitric oxide system and morphology

OBJECTIVE Fetal and postnatal zinc deficiencies induce an increase in arterial blood pressure and impair renal function in male adult rats. We therefore hypothesized that these renal alterations are present in early stages of life and that there are sexual differences in the adaptations to this nutritional injury. The aim was to study the effects of moderate zinc deficiency during fetal life and lactation on renal morphology, oxidative stress, apoptosis, and the nitric oxide system in male and female rats at 21 d of life. METHODS Female Wistar rats received low (8 ppm) or control (30 ppm) zinc diets from the beginning of pregnancy to weaning. Glomerulus number, morphology, oxidative stress, apoptotic cells, nitric oxide synthase activity, and protein expression were evaluated in the kidneys of offspring at 21 d. RESULTS Zinc deficiency decreased the nephron number, induced glomerular hypertrophy, increased oxidative damage, and decreased nitric oxide synthase activity in the male and female rat kidneys. Nitric oxide synthase activity was not affected by inhibitors of the neuronal or inducible isoforms, so nitric oxide was mainly generated by the endothelial isoenzyme. Gender differences were observed in glomerular areas and antioxidant enzyme activities. CONCLUSION Zinc deficiency during fetal life and lactation induces an early decrease in renal functional units, associated with a decrease in nitric oxide activity and an increase in oxidative stress, which would contribute to increased arterial blood pressure and renal dysfunction in adulthood. The sexual differences observed in this model may explain the dissimilar development of hypertension and renal diseases in adult life.

Morphological and functional effects on cardiac tissue induced by moderate zinc deficiency during prenatal and postnatal life in male and female rats

The aim of this study was to evaluate whether moderate zinc restriction in rats throughout fetal life, lactation, and/or postweaning growth results in early changes in cardiac morphology predisposing the onset of cardiac dysfunction in adult life as well as sex-related differences in the adaptation to this nutritional injury. Female Wistar rats received low or control zinc diets from the beginning of pregnancy up to offspring weaning. After being weaned, offspring were fed either a low or control zinc diet until 81 days. Systolic blood pressure was measured. Echocardiographic and electrocardiographic examinations, morphological experiments, and apoptosis by TUNEL assay were performed in the left ventricle. In the early stages, zinc-deficient male and female offspring showed an increase in cardiomyocyte diameter, probably associated with an increase in cardiac apoptotic cells, but smaller myocyte diameters in adulthood. In adult males, this nutritional injury induced decreased contractility and dilatation of the left ventricle, not allowing the heart to compensate the higher levels of blood pressure, and hypertrophic remodeling of coronary arteries associated with increased blood pressure. Adequate zinc intake during postweaning life did not overcome blood pressure levels but reversed some of the detrimental effects of earlier zinc deficiency in cardiac morphology and function. Females were less sensitive to this deficiency, exhibiting normal levels of blood pressure and no structural or functional heart alterations in adult life. The present study demonstrates that the effects of zinc deficiency on blood pressure, cardiac morphology, and function differ between sexes, with males more predisposed to develop cardiovascular diseases in adulthood.

Zirfon® as Separator Material for Water Electrolysis Under Specific Conditions

Hydrogen production through alkaline water electrolysis requires improvements to use renewable energy more efficiently. In the process of converting electrical to chemical energy, efforts are focused on reducing energy loss. Electrolysers play two important roles in this process: one of them is as a hydrogen producer and the other is as a storage mechanism. A storage mechanism occurs when there is an excess of renewable energy that can be stored in the form of hydrogen (chemical energy), which is the fuel for the following step, turning chemical into electrical energy again. Electrolysers research is focused on: separators and electrodes materials, electrolytic solutions and cell design. The ideal situation for a separator in an electrolyser is to possess low electric resistance. For that purpose, we compared Zirfon®, silicone and the system without separator. This work studied the behaviour of Zirfon® under specific working conditions: room temperature, an electrolytic solution of potassium hydroxide 35 % w/w and five different distances between electrodes. In order to carry out this experiment, we designed and constructed a special electrolytic cell. The experimental results showed that Zirfon® separator increases the system resistance approximately 15 % when compared to the same system without separator, but it reduces resistance when compared to silicone (excellent insulator). Another result proved that the distances between electrodes proposed in this work did not show bubbles resistance because the system performance improved as the distance became shorter.

Funcionamiento y Estabilidad en el Tiempo de un Sistema Energético con Batería PEM a Combustible y sus Componentes Periféricos

En este trabajo se presenta el desarrollo completo de una bateria de tipo membrana de electrolito polimerico (proton exchange membrane fuel cell stack, PEMFCS), y se muestra el funcionamiento de un sistema experimental completo que esta siendo probado en la Base Esperanza que el Ejercito Argentino posee en la Antartida. El conjunto desarrollado permite trabajar con un minimo de componentes perifericos y ser manejado por personal entrenado con capacitacion basica para su operacion y mantenimiento. La resistencia ohmica de la bateria no difiere de la que se obtendria con seis elementos en serie; su pendiente de Tafel es de 80 mV/dec. Las pruebas de estabilidad en el tiempo alcanzaron 2278 horas y la energia entregada en ese tiempo fue de 4.2 kWh.

A Simple and Inexpensive Method for Evaluating the Photovoltaic Potential: Its Validation in Buenos Aires and Antarctica

The use of renewable energies requires a precise and detailed quantification of the resource available. Because of the cost of solar stations or limited availability of skilled human resources, in most emerging countries, this assessment is made only on a few points scattered over large areas. We report here a simple and inexpensive method to evaluate the photovoltaic (PV) potential for a specific geographic region and a given PV capture technology. The system allows for a direct evaluation of the energy actually obtainable by scaling the measurement array of photovoltaic cells. The proposed measurement system can be installed as a stand-alone unit, or as part of a measurement network, connected to a more sophisticated central hub. The measurement station consists of said PV array (or similar PV array), a resistor, and a portable data logger. The system is calibrated with a device composed of a small array of PV cells, a resistor load bank, and two multimeters. Due to its low cost, this system can be replicated as many times as required with minimal investment. This would make it possible to evaluate the available photovoltaic potential of large regions with accurate and detailed data. Measurements carried out in Buenos Aires and in Antarctica confirm the consistency of the method.