RESUMO

This study investigates the fabrication process of copper thin films via thermal evaporation, with precise control over film thickness achieved throughZ-position adjustment. Analysis of the as-fabricated copper films reveals a discernible relationship between grain size (〈D〉) andZ-position, characterized by a phenomenological equation〈D〉XRDn(Z)=〈D〉0n1+32rZ2+158rZ4, which is further supported by a growth exponent (n) of 0.41 obtained from the analysis. This value aligns well with findings in the literature concerning the growth of copper films, thus underlining the validity and reliability of our experimental outcomes. The resulting crystallites, ranging in size from 20 to 26 nm, exhibit a resistivity within the range of 3.3-4.6µΩ · cm. Upon thermal annealing at 200 °C, cuprite Cu2O thin films are produced, demonstrating crystallite sizes ranging from ∼9 to ∼24 nm with increasing film thickness. The observed monotonic reduction in Cu2O crystallites relative to film thickness is attributed to a recrystallization process, indicating amorphization when oxygen atoms are introduced, followed by the nucleation and growth of newly formed copper oxide phase. Changes in the optical bandgap of the Cu2O films, ranging from 2.31 to 2.07 eV, are attributed mainly to the quantum confinement effect, particularly important in Cu2O with size close than the Bohr exciton diameter (5 nm) of the Cu2O. Additionally, correlations between refractive index and extinction coefficient with film thickness are observed, notably a linear relationship between refractive index and charge carrier density. Electrical measurements confirm the presence of a p-type semiconductor with carrier concentrations of ∼1014cm-3, showing a slight decrease with film thickness. This phenomenon is likely attributed to escalating film roughness, which introduces supplementary scattering mechanisms for charge carriers, leading to a resistivity increase, especially as the roughness approaches or surpasses the mean free path of charge carriers (8.61 nm). Moreover,ab-initiocalculations on the Cu2O crystalline phase to investigate the impact of hydrostatic strain on its electronic and optical properties was conducted. We believe that our findings provide crucial insights that support the elucidation of the experimental results. Notably, thinner cuprite films exhibit heightened sensitivity to ethanol gas at room temperature, indicating potential for highly responsive gas sensors, particularly for ethanol breath testing, with significant implications for portable device applications.

RESUMO

Water is an essential compound on earth and necessary for life. The presence of highly toxic contaminants such as arsenic and others, in many cases, represents one of the biggest problems facing the earth´s population. Treatment of contaminated water with magnetite (Fe3O4) nanoparticles (NPs) can play a crucial role in arsenic removal. In this report, we demonstrate arsenic removal from an aqueous solution and natural water taken from the Peruvian river (Tambo River in Arequipa, Peru) using magnetite NPs synthesized by the coprecipitation method. XRD data analysis of Fe3O4 NPs revealed the formation of the cubic-spinel phase of magnetite with an average crystallite size of ~ 13 nm, which is found in good agreement with the physical size assessed from TEM image analysis. Magnetic results evidence that our NPs show a superparamagnetic-like behavior with a thermal relaxation of magnetic moments mediated by strong particle-particle interactions. FTIR absorption band shows the interactions between arsenate anions and Fe-O and Fe-OH groups through a complex mechanism. The experimental results showed that arsenic adsorption is fast during the first 10 min; while the equilibrium is reached within 60 min, providing an arsenic removal efficiency of ~ 97%. Adsorption kinetics is well modeled using the pseudo-second-order kinetic equation, suggesting that the adsorption process is related to the chemisorption model. According to Langmuir's model, the maximum arsenic adsorption capacity of 81.04 mg·g- 1 at pH = 2.5 was estimated, which describes the adsorption process as being monolayer, However, our results suggest that multilayer adsorption can be produced after monolayer saturation in agreement with the Freundlich model. This finding was corroborated by the Sips model, which showed a good correlation to the experimental data. Tests using natural water taken from Tambo River indicate a significant reduction of arsenic concentration from 356 µg L- 1 to 7.38 µg L- 1, the latter is below the limit imposed by World Health Organization (10 µg L- 1), suggesting that magnetite NPs show great potential for the arsenic removal.

RESUMO

In this work, we present a coupled experimental and theoretical first-principles investigation on one of the more promising oxide-diluted magnetic semiconductors, the Sn1-xCoxO2 nanoparticle system, in order to see the effect of cobalt doping on the physical and chemical properties. Our findings suggest that progressive surface enrichment with dopant ions plays an essential role in the monotonous quenching of the surface disorder modes. That weakening is associated with the passivation of the oxygen vacancies as the Co excess at the surface becomes larger. Room-temperature 119Sn Mössbauer spectroscopy data analysis revealed the occurrence of a distribution of isomer shifts, related to the different non-equivalent surroundings of Sn4+ ions and the coexistence of Sn2+/Sn4+ at the particle surfaces provoked by the inhomogeneous distribution of Co ions, in agreement with the X-ray photoelectron spectroscopy measurements. Magnetic measurements revealed a paramagnetic behavior of the Co ions dispersed in the rutile-type matrix with antiferromagnetic correlations, which become stronger as the Co content is increased. Theoretical calculations show that a defect with two Co mediated by a nearby oxygen vacancy is the most likely defect. The predicted effects of this defect complex are in accordance with the experimental results.

RESUMO

ABSTRACT Aiming at developing a tool for assessing the magnitude of farm animal health, an indicator named herd animal health status was built. To illustrate the construction of the indicator, serum samples were taken from 923 goats on 17 goat farms in the state of Sao Paulo, Brazil, where three diseases were evaluated along with their impact percentages: caprine arthritis encephalitis, toxoplasmosis and neosporose all of an infectious and transmissible nature and the cause of considerable economic losses. The mathematical rationale underlying the building of the animal health status indicator ranks properties on a 0 - 100% scale in terms of disease positivity in the herd, with the lowest indicator value indicating the highest cumulative disease frequency (0% = all animals tested positive for the three diseases, 100% = all animals tested negative for all diseases). Anti-T. gondii, anti-N. caninum and anti-CAEV antibodies were tested using indirect immunofluorescence reaction (IIFR 16), Neospora agglutination test (NAT 25) and agarose gel immunodiffusion (AGID positive or negative), respectively. The animal health status of the farms ranged from 32.38% to 96.40% according to disease positivity. The animal health status value will have a direct reflection on the production chain both on and off the farm, providing not only great market advantages, due to how the expression of animal health will add value to livestock farms, as well as on the consumer who can check the quality of animal health at the beginning of the production chain.

RESUMO Visando à construção de uma ferramenta de trabalho que permitisse expressar a grandeza da saúde animal de propriedades rurais, foi construído um indicador resultante da qualidade da saúde do rebanho denominado status de saúde animal. Como exemplo para a construção do indicador, tomaram-se os soros de 923 caprinos oriundos de 17 capris do Estado de São Paulo, nos quais se avaliaram três enfermidades e seus respectivos impactos percentuais: a artrite-encefalite caprina, a neosporose e a toxoplasmose - todas de caráter infeccioso e transmissível e que ocasionam consideráveis perdas econômicas. A lógica da construção matemática do status de saúde animal classifica a propriedade numa variação de 0 a 100%, conforme a positividade das enfermidades no rebanho: quanto maior a frequência acumulativa de ocorrência das doenças nos animais, menor o valor do indicador, chegando ao limite de 0% - quando todos os animais estiverem positivos às três enfermidades e de 100% - quando todo o rebanho for negativo. Para detecção de anticorpos anti-T. gondii, anti-N. caninum e anti-CAEV, foram utilizados, respectivamente, reação de imunofluorescência indireta (RIFI 16), teste de aglutinação para Neospora (NAT 25) e imunodifusão em gel de agarose (IDGA positivo ou negativo). O status de saúde animal das propriedades rurais variou de 32,38% a 96,40%, de acordo com a ocorrência de positividade para as enfermidades. A característica do valor do status de saúde animal terá reflexo direto na cadeia de produção dentro e fora da fazenda, proporcionando não somente enormes vantagens mercadológicas, devido à expressão que a saúde animal terá para agregar valor às propriedades rurais de produção animal, mas também no consumidor final que poderá verificar a qualidade da saúde animal no início da cadeia de produção.

RESUMO

Visando à construção de uma ferramenta de trabalho que permitisse expressar a grandeza da saúde animal de propriedades rurais, foi construído um indicador resultante da qualidade da saúde do rebanho denominado "status de saúde animal". Como exemplo para a construção do indicador, tomaram-se os soros de 923 caprinos oriundos de 17 capris do Estado de São Paulo, nos quais se avaliaram três enfermidades e seus respectivos impactos percentuais: a artrite-encefalite caprina, a neosporose e a toxoplasmose - todas de caráter infeccioso e transmissível e que ocasionam consideráveis perdas econômicas. A lógica da construção matemática do "status de saúde animal" classifica a propriedade numa variação de 0 a 100%, conforme a positividade das enfermidades no rebanho: quanto maior a frequência acumulativa de ocorrência das doenças nos animais, menor o valor do indicador, chegando ao limite de 0% - quando todos os animais estiverem positivos às três enfermidades e de 100% - quando todo o rebanho for negativo. Para detecção de anticorpos anti-T. gondii, anti-N. caninum e anti-CAEV, foram utilizados, respectivamente, reação de imunofluorescência indireta (RIFI ≥ 16), teste de aglutinação para Neospora (NAT ≥ 25) e imunodifusão em gel de agarose (IDGA positivo ou negativo). O "status de saúde animal" das propriedades rurais variou de 32,38% a 96,40%, de acordo com a ocorrência de positividade para as enfermidades. A característica do valor do "status de saúde animal" terá reflexo direto na cadeia de produção dentro e fora da fazenda, proporcionando não somente enormes vantagens mercadológicas, devido à expressão que a saúde animal terá para agregar valor às propriedades rurais de produção animal, mas também no consumidor final que poderá verificar a qualidade da saúde animal no início da cadeia de produção.

Aiming at developing a tool for assessing the magnitude of farm animal health, an indicator named herd "animal health status" was built. To illustrate the construction of the indicator, serum samples were taken from 923 goats on 17 goat farms in the state of Sao Paulo, Brazil, where three diseases were evaluated along with their impact percentages: caprine arthritis encephalitis, toxoplasmosis and neosporose ­ all of an infectious and transmissible nature and the cause of considerable economic losses. The mathematical rationale underlying the building of the "animal health status" indicator ranks properties on a 0 - 100% scale in terms of disease positivity in the herd, with the lowest indicator value indicating the highest cumulative disease frequency (0% = all animals tested positive for the three diseases, 100% = all animals tested negative for all diseases). Anti-T. gondii, anti-N. caninum and anti-CAEV antibodies were tested using indirect immunofluorescence reaction (IIFR ≥ 16), Neospora agglutination test (NAT ≥ 25) and agarose gel immunodiffusion (AGID positive or negative), respectively. The animal health status of the farms ranged from 32.38% to 96.40% according to disease positivity. The animal health status value will have a direct reflection on the production chain both on and off the farm, providing not only great market advantages, due to how the expression of animal health will add value to livestock farms, as well as on the consumer who can check the quality of animal health at the beginning of the production chain.

Assuntos

RESUMO

We have shown that myocardial dysfunction induced by food restriction is related to calcium handling. Although cardiac function is depressed in food-restricted animals, there is limited information about the molecular mechanisms that lead to this abnormality. The present study evaluated the effects of food restriction on calcium cycling, focusing on sarcoplasmic Ca2+-ATPase (SERCA2), phospholamban (PLB), and ryanodine channel (RYR2) mRNA expressions in rat myocardium. Male Wistar-Kyoto rats, 60 days old, were submitted to ad libitum feeding (control rats) or 50% diet restriction for 90 days. The levels of left ventricle SERCA2, PLB, and RYR2 were measured using semi-quantitative RT-PCR. Body and ventricular weights were reduced in 50% food-restricted animals. RYR2 mRNA was significantly decreased in the left ventricle of the food-restricted group (control = 5.92 +/- 0.48 vs food-restricted group = 4.84 +/- 0.33, P < 0.01). The levels of SERCA2 and PLB mRNA were similar between groups (control = 8.38 +/- 0.44 vs food-restricted group = 7.96 +/- 0.45, and control = 1.52 +/- 0.06 vs food-restricted group = 1.53 +/- 0.10, respectively). Down-regulation of RYR2 mRNA expressions suggests that chronic food restriction promotes abnormalities in sarcoplasmic reticulum Ca2+ release.

Assuntos

RESUMO

We have shown that myocardial dysfunction induced by food restriction is related to calcium handling. Although cardiac function is depressed in food-restricted animals, there is limited information about the molecular mechanisms that lead to this abnormality. The present study evaluated the effects of food restriction on calcium cycling, focusing on sarcoplasmic Ca2+-ATPase (SERCA2), phospholamban (PLB), and ryanodine channel (RYR2) mRNA expressions in rat myocardium. Male Wistar-Kyoto rats, 60 days old, were submitted to ad libitum feeding (control rats) or 50 percent diet restriction for 90 days. The levels of left ventricle SERCA2, PLB, and RYR2 were measured using semi-quantitative RT-PCR. Body and ventricular weights were reduced in 50 percent food-restricted animals. RYR2 mRNA was significantly decreased in the left ventricle of the food-restricted group (control = 5.92 ± 0.48 vs food-restricted group = 4.84 ± 0.33, P < 0.01). The levels of SERCA2 and PLB mRNA were similar between groups (control = 8.38 ± 0.44 vs food-restricted group = 7.96 ± 0.45, and control = 1.52 ± 0.06 vs food-restricted group = 1.53 ± 0.10, respectively). Down-regulation of RYR2 mRNA expressions suggests that chronic food restriction promotes abnormalities in sarcoplasmic reticulum Ca2+ release.

Assuntos

RESUMO

Diets rich in saturated fatty acids are one of the most important causes of atherosclerosis in men, and have been replaced with diets rich in unsaturated fatty acids (UFA) for the prevention of this disorder. However, the effect of UFA on myocardial performance, metabolism and morphology has not been completely characterized. The objective of the present investigation was to evaluate the effects of a UFA-rich diet on cardiac muscle function, oxidative stress, and morphology. Sixty-day-old male Wistar rats were fed a control (N = 8) or a UFA-rich diet (N = 8) for 60 days. Myocardial performance was studied in isolated papillary muscle by isometric and isotonic contractions under basal conditions after calcium chloride (5.2 mM) and ss-adrenergic stimulation with 1.0 microM isoproterenol. Fragments of the left ventricle free wall were used to study oxidative stress and were analyzed by light microscopy, and the myocardial ultrastructure was examined in left ventricle papillary muscle. After 60 days the UFA-rich diet did not change myocardial function. However, it caused high lipid hydroperoxide (176 +/- 5 vs 158 +/- 5, P < 0.0005) and low catalase (7 +/- 1 vs 9 +/- 1, P < 0.005) and superoxide-dismutase (18 +/- 2 vs 27 +/- 5, P < 0.005) levels, and discrete morphological changes in UFA-rich diet hearts such as lipid deposits and mitochondrial membrane alterations compared to control rats. These data show that a UFA-rich diet caused myocardial oxidative stress and mild structural alterations, but did not change mechanical function.

Assuntos

RESUMO

Diets rich in saturated fatty acids are one of the most important causes of atherosclerosis in men, and have been replaced with diets rich in unsaturated fatty acids (UFA) for the prevention of this disorder. However, the effect of UFA on myocardial performance, metabolism and morphology has not been completely characterized. The objective of the present investigation was to evaluate the effects of a UFA-rich diet on cardiac muscle function, oxidative stress, and morphology. Sixty-day-old male Wistar rats were fed a control (N = 8) or a UFA-rich diet (N = 8) for 60 days. Myocardial performance was studied in isolated papillary muscle by isometric and isotonic contractions under basal conditions after calcium chloride (5.2 mM) and ß-adrenergic stimulation with 1.0 æM isoproterenol. Fragments of the left ventricle free wall were used to study oxidative stress and were analyzed by light microscopy, and the myocardial ultrastructure was examined in left ventricle papillary muscle. After 60 days the UFA-rich diet did not change myocardial function. However, it caused high lipid hydroperoxide (176 ± 5 vs 158 ± 5, P < 0.0005) and low catalase (7 ± 1 vs 9 ± 1, P < 0.005) and superoxide-dismutase (18 ± 2 vs 27 ± 5, P < 0.005) levels, and discrete morphological changes in UFA-rich diet hearts such as lipid deposits and mitochondrial membrane alterations compared to control rats. These data show that a UFA-rich diet caused myocardial oxidative stress and mild structural alterations, but did not change mechanical function.

Assuntos

RESUMO

The interrelation between thyroid gland and clinical changes was studied in adult intact cats kept under hyperthyroid state for 42 days. Parameters measured were red blood cell count (RBC), haemoglobin concentration, haematocrit, MCV, MCHC, total leukocytes (WBC) and differential leukocyte count. These characteristics were correlated with free and total T4 and total T3 serum concentrations. Excessive circulant thyroid hormones led to increased RBC, haematocrit, MCV, WBC, neutrophils, lymphocytes, eosinophils and monocytes in the studied cats. There were negative correlation between RBC and total T4 at the first weeks but positive correlation at the end of the experimental period. Leukocytes demonstrated negative correlation with free and total T4 levels. KEY-WORDS: Feline. Complete blood count. Hyperthyroidism.

A relação da glândula tireóide com valores hematológicos foi avaliada em gatos adultos, intactos e mantidos em estado hipertireóideo por um período de 42 dias. Os parâmetros estudados foram contagem total de hemácias, concentração de hemoglobina, hematócrito, concentração de hemoglobina corpuscular média, volume corpuscular médio, leucócitos totais e o diferencial e suas associações . Foram correlacionadas as variáveis com os níveis de tiroxina total (TT4), tiroxina livre (LT4) e triiodotironina total (TT3). O aumento dos níveis séricos dos hormônios tireoidianos provocou aumento de hemácias, hematócrito, hemoglobina, leucócitos, dos neutrófilos, linfócitos, eosinófilos e monócitos nos gatos. A contagem total de hemácias em relação à TT4 apresentou correlação negativa nos momentos iniciais e positiva nos finais. Os leucócitos apresentaram correlação negativa com a TT4 e LT4.PALAVRAS-CHAVE: Felino. Hemograma. Hipertireoidismo. Tireotoxicose.