Cadmium affects the mitochondrial viability and the acid soluble thiols concentration in liver, kidney, heart and gills of Ancistrus brevifilis (Eigenmann, 1920)

The freshwater fish Ancistrus brevifilis, which is found in Venezuelan rivers, is considered a potential sentinel fish in ecotoxicological studies. The cadmium (Cd) effect on the mitochondrial viability (MV) and acid soluble thiols levels (AST) in A. brevifilis tissues (liver, kidney, heart, and gill) was evaluated. Forty-two fish with similar sizes and weights were randomly selected, of which 7 fish (with their respective replicate) were exposed for 7 and 30 days to a Cd sublethal concentration (0.1 mg.l-1). We determined the MV through a Janus Green B colorimetric assay and we obtained the concentration of AST by Ellman’s method. Mitochondrial viability decreased in fish exposed to Cd for 30 days with the liver being the most affected tissue. We also detected a significant decrease in AST levels was in fishes exposed to Cd for 7 days in liver and kidney tissues; these results suggests that AST levels are elevated in some tissues may act as cytoprotective and adaptive alternative mechanism related to the ROS detoxification, maintenance redox status and mitochondrial viability. Organ-specifics variations were observed in both assays. We conclude that the Cd exposure effect on AST levels and MV, vary across fish tissues and is related to the exposure duration, the molecule dynamics in different tissues, the organism and environmental conditions.Keywords: Ancistrus brevifilis, Cadmium, Soluble thiols, Janus Green B, Mitochondrial viability

Lyapunov Based 3D Path Following Kinematic Controller for a Fixed Wing UAV

International audiencePath following is a basic autonomous navigation capability for UAV’s and in this paper we present a nonlinear 3D path following kinematic controller. In order to solve this problem, we use the typical multi-loop control structure in which the navigation controller directs the aircraft to the desired path, while the inner loop acts as an autopilot which stabilizes the nonlinear dynamics and tracks the command generated by the outer loop. Under the assumption that the autopilot is well tuned and the airspeed, fight-path angle, and bank angle states converge to the desired response to their commanded values, we use a kinematic model as a suitable control model for the fixed wing UAV. With the introduction of a virtual target, the proposed Lyapunov based kinematic controller for outer loop can steer the UAV asymptotically to approach the desired path. The proposed controller is validated in a 6-DoF simulation environment platform named MAV3DSim

Cadmium affects the mitochondrial viability and the acid soluble thiols concentration in liver, kidney, heart and gills of Ancistrus brevifilis (Eigenmann, 1920)

The freshwater fish Ancistrus brevifilis, which is found in Venezuelan rivers, is considered a potential sentinel fish in ecotoxicological studies. The cadmium (Cd) effect on the mitochondrial viability (MV) and acid soluble thiols levels (AST) in A. brevifilis tissues (liver, kidney, heart, and gill) was evaluated. Forty-two fish with similar sizes and weights were randomly selected, of which 7 fish (with their respective replicate) were exposed for 7 and 30 days to a Cd sublethal concentration (0.1 mg.l-1). We determined the MV through a Janus Green B colorimetric assay and we obtained the concentration of AST by Ellman’s method. Mitochondrial viability decreased in fish exposed to Cd for 30 days with the liver being the most affected tissue. We also detected a significant decrease in AST levels was in fishes exposed to Cd for 7 days in liver and kidney tissues; these results suggests that AST levels are elevated in some tissues may act as cytoprotective and adaptive alternative mechanism related to the ROS detoxification, maintenance redox status and mitochondrial viability. Organ-specifics variations were observed in both assays. We conclude that the Cd exposure effect on AST levels and MV, vary across fish tissues and is related to the exposure duration, the molecule dynamics in different tissues, the organism and environmental conditions.Keywords: Ancistrus brevifilis, Cadmium, Soluble thiols, Janus Green B, Mitochondrial viability

Histopathological changes in the head kidney induced by cadmium in a neotropical fish Colossoma macropomum

We evaluated the effect of cadmium (Cd) on the structure and function of the head kidney in the freshwater fish Colossoma macropomum (C. macropomum). Juveniles were exposed to 0.1 mg/L CdCl2 for 31 days. Blood samples were examined using hematological tests and head kidney histology was determined by light microscopy. The concentration of Cd in the head and trunk kidneys was measured using an atomic absorption spectrophotometer. Cd produced histopathological changes in the head kidney, the most evident of these being: the thickening of the vein wall, an increase in the number of basophils/mast cells close to blood vessels and a severe depletion of hematopoietic precursors especially the granulopoietic series. In the blood, a decrease in the total leucocytes and hemoglobin concentration was observed. Cd-exposed fish showed higher Cd concentrations in the trunk kidney than the head kidney. In conclusion, exposure to Cd affected precursor hematopoietic cells in C. macropomum.Keywords: Cadmium, Colossoma macropomum, Granulocytes, Head kidney, Histology

Parametric Analysis of a Two-Shaft Aeroderivate Gas Turbine of 11.86 MW

The aeroderivate gas turbines are widely used for power generation in the oil and gas industry. In offshore marine platforms, the aeroderivative gas turbines provide the energy required to drive mechanically compressors, pumps and electric generators. Therefore, the study of the performance of aeroderivate gas turbines based on a parametric analysis is relevant to carry out a diagnostic of the engine, which can lead to operational as well as predictive and/or corrective maintenance actions. This work presents a methodology based on the exergetic analysis to estimate the irrevesibilities and exergetic efficiencies of the main components of a two-shaft aeroderivate gas turbine. The studied engine is the Solar Turbine Mars 100, which is rated to provide 11.86 MW. In this engine, the air is compressed in an axial compressor achieving a pressure ratio of 17.7 relative to ambient conditions and a high pressure turbine inlet temperature of 1220 °C. Even if the thermal efficiency associated to the pressure ratio of 17.7 is 1% lower than the maximum thermal efficiency, the irreversibilities related to this pressure ratio decrease approximately 1 GW with respect to irreversibilities of the optimal pressure ratio for the thermal efficiency. In addition, this paper contributes to develop a mathematical model to estimate the high turbine inlet temperature as well as the pressure ratio of the low and high pressure turbines

Relation between metallothionein, RNA/DNA and heavy metals in juveniles of

Metal content, Metallotionein and physiological condition (RNA/DNA ratio) were analyzed in Cachama, Colossoma macropomum from the Orinoco River. Juvenile samples were dissected and one gram of white muscle gills, kidney and liver was taken. Cu, Cd, Pb, Ni and Fe were analyzed by atomic absorption spectrophotometer using TORT and LUTSI as reference material. Metallothioneins were determined with Ellman´s reagent and RNA/DNA ratio was analyzed by fluorometric method. Results showed that Cd, Cu, Ni, Fe, and Pb levels were significantly higher in liver than muscle. There was no difference statistically between Mts concentrations in liver, kidney and gills; muscle showed the lowest Mts concentrations. Multivariate analysis ACP determined relationship between Mts-L and Cu and Mts-G and Cd. The Mts in muscle was related with Pb and Cd. There was no association between physiological condition and metals concentrations, however, the RNA/ DNA showed relationship with Mts-M and Mts-

Prediction of carcass energy content of Pelibuey ewes by ultrasound measurements

The aim of this study was to evalúate the relationship between body ultrasound measurements (USM) and carcass energy content (CEC) of Pelibuey ewes. USM were taken 24 h before slaughter in twenty-two ewes. Fat thickness (FT) and Longissimus dorsi area (LDA) were determined in the thoracic (TFT and TLDA) and lumbar región (LFT and LLDA). CEC was considered as the sum of the energy of muscle and adipose tissues in the carcass. The correlation coefficient (r) between body weight (BW) and CEC was 0.89 (p 0.05). The r2 for equation including BW and LFT was 0.87 (RSD= 15.34). The inclusión of LFT improved the prediction by about 8 %. The use of some USM in combination with BW provides good CEC estimates in Pelibuey ewes.El objetivo fue evaluar la relación entre mediciones corporales por ultrasonido (MUS) y el contenido de energía de la canal (CEC) de ovejas Pelibuey. Las MUS se registraron 24 h antes del sacrificio en 22 ovejas. El espesor de grasa (EG) y el área del Longissimus dorsi (ALD) fueron determinados en la región torácica (EGT y ALDT) y lumbar (EGL y ALDL). El CEC se consideró como la suma de la energía del tejido muscular y adiposo en la canal. El coeficiente de correlación (r) entre el peso vivo (PV) y CEC fue de 0.89 (p 0.05). La ecuación que incluyó al PV y EGL, tuvo una r2 de 0.87. La inclusión de EGL mejoró la predicción en un 8 %. El uso de algunas MUS en combinación con el PV en ovejas Pelibuey proporciona buenas estimaciones del CEC

Prediction of carcass energy content of Pelibuey ewes by ultrasound measurements/ Predicción del contenido de energético de la canal de ovejas Pelibuey por mediciones de ultrasonido

The aim of this study was to evaluate the relationship between body ultrasound measurements (USM) and carcass energy content (CEC) of Pelibuey ewes. USM were taken 24 h before slaughter in twenty-two ewes. Fat thickness (FT) and Longissimus dorsi area (LDA) were determined in the thoracic (TFT and TLDA) and lumbar region (LFT and LLDA). CEC was considered as the sum of the energy of muscle and adipose tissues in the carcass. The correlation coecient (r) between body weight (BW) and CEC was 0.89 (p < 0.001). Nonetheless, correlations for LDA and CEC were not signicant (p > 0.05). The r2 for equation including BW and LFT was 0.87 (RSD= 15.34). The inclusion of LFT improved the prediction by about 8 %. The use of some USM in combination with BW provides good CEC estimates in Pelibuey ewe