34 research outputs found

    Effects of yeast extract supplemented in diet on growth performance, digestibility, intestinal histology, and the antioxidant capacity of the juvenile turbot (Scophthalmus maximus)

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    An 8-week feeding experiment was conducted on the juvenile turbot (Scophthalmus maximus) to evaluate the influence of yeast extract (YE) supplementation in the diet on growth performance, feed utilization, body composition, nutrient digestibility, intestinal histology, and antioxidant capacity. Four experimental diets were formulated with graded levels of yeast extract 0 (YE0), 1% (YE1), 3% (YE3), and 5% (YE5) and fed to turbots (initial body weight: 4.2 ± 0.1 g) with three replicates per diet and 200 fish in each replicate, respectively. The results showed that turbots fed with diets YE1 and YE3 displayed a significantly higher specific growth rate and protein efficiency rate than those fed with diets YE0 and YE5, while the feed conversion ratios in YE1 and YE3 groups were lower than those in YE0 and YE5. Fish fed with diets YE3 and YE5 showed higher body crude protein contents than those in groups YE0 and YE1. The highest apparent digestibility coefficients for dry matter and crude protein, digestive enzyme activities (trypsin, lipase, and amylase), and the height of the intestinal fold were observed in the YE3 group. YE3 treatment displayed a significantly higher superoxide dismutase (SOD) activity than the YE0 group, while the malondialdehyde (MDA) content in YE1 was significantly lower than those in YE0 and YE5. No significant difference was observed in serum physiological and biochemical parameters among all treatments. Overall, appropriate dietary supplementation of the yeast extract could improve the growth performance, digestibility, and antioxidant capacity of the juvenile turbot, and the recommended yeast extract level in the feed is 2.47%

    Asiatic acid inhibits lung cancer cell growth in vitro and in vivo by destroying mitochondria

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    Asiatic acid (AA), a pentacyclic triterpene found in Centella asiatica, displays significant anti-proliferative effects on cancer cells in vitro although the underlying mechanism of this effect remains unknown. This study investigated the efficacy and mechanism of action of AA against lung cancer both in vivo and in vitro. Using the MTT assay, AA was found to induce apoptosis in a dose- and time-dependent manner, an effect enhanced by pretreatment with an autophagy inhibitor. It also elevated expression of microtubule-associated protein 1 light chain 3 (LC3) and decreased the expression of p62. Furthermore, exposure to AA resulted in collapse of the mitochondrial membrane potential and generation of reactive oxygen species (ROS), suggesting mitochondria are the target of AA. In the mouse lung cancer xenograft model, oral administration of AA significantly inhibited tumor volume and weight accompanied by significant apoptosis of lung cancer cells. In addition, it led to a significant decrease in the expression of proliferating cell nuclear antigen (PCNA). In summary, the results show that AA significantly reduces lung cancer cell growth both in vitro and in vivo and that the associated apoptosis is mediated through mitochondrial damage

    Reinforced Structure Effect on Thermo-Oxidative Stability of Polymer-Matrix Composites: 2-D Plain Woven Composites and 2.5-D Angle-Interlock Woven Composites

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    The thermo-oxidative stability of carbon fiber polymer matrix composites with different integral reinforced structures was investigated experimentally and numerically. Specimens of 2-D plain woven composites and 2.5-D angle-interlock woven composites were isothermally aged at 180 °C in hot air for various durations up to 32 days. The thermal oxidative ageing led to the degradation of the matrix and the fiber/matrix interface. The degradation mechanisms of the matrix were examined by ATR-FTIR and thermal analysis. The interface cracks caused by thermal oxidative ageing were sensitive to the reinforced structure. The thermo-oxidative stability of the two composites was numerically compared in terms of matrix shrinking and crack evolution and then experimentally validated by interlaminar shear tests

    Titanate nanotube-promoted chemical fixation of carbon dioxide to cyclic carbonate: a combined experimental and computational study

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    Titanate nanotubes (TNT) were found to be air-and water-tolerant, efficient, and recyclable Lewis acid catalysts towards the cycloaddition of carbon dioxide (CO2) to propylene oxide (PO) for the synthesis of cyclic propylene carbonate (PC). Using TNT as the catalyst and potassium iodide, tetrabutylammonium bromide or tetraphenylphosphonium bromide as the co-catalyst, PO was readily converted to PC with a yield of up to >99.9% and a PC selectivity of 100% under relatively mild conditions. Experimental research revealed that the TNT catalyst with the highest exposure of active sites, including surface hydroxyl groups and Lewis acid sites, proved to be the most active for the cycloaddition reaction. Our theoretical evaluation based on density functional theory calculations further indicated that the high Lewis acidity of TNT strongly reduces the energy barrier for the ring-opening step through the polarization of the C-O bond of PO, which allows a subsequent nucleophilic attack easily. Both experimental and computational studies demonstrated that the synergetic effect between TNT and the co-catalyst plays an important role in PC formation. The TNT catalyst is richer in surface Lewis acid sites, shows a large surface area and mesoporous structure, and has a heterogeneous and recyclable nature, which makes TNT an excellent, interesting and ideal catalyst for chemical fixation of CO2

    Arabidopsis MYB24 Regulates Jasmonate-Mediated Stamen Development

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    Tesis (Abogado)--Universidad de Piura. Facultad de Derecho, 2014.La presente investigación, aborda el análisis de las causales por las que los órganos revisores deben declarar la nulidad procesal, a fin de no caer en dilaciones procesales indebidas. Declaración de nulidad es una medida extrema , que hoy en día es mal aplicada por algunos órganos jurisdiccionales empleándola indiscriminadamente en los procesos judiciales, ocasionando perjuicio directo a las partes procesales, asi como a la misma administración de justicia en general. El estudio constituye la propuesta de una medida para impulsar la mejora del funcionamiento del Poder Judicial como entidad encargada de la administración de justicia en nuestra nación

    Arabidopsis MYB24 Regulates Jasmonate-Mediated Stamen Development

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    The phytohormone jasmonates (JAs) regulate various defense responses and diverse developmental processes including stamen development and fertility. Previous studies showed that JA induces CORONATINE INSENSITIVE 1-mediated degradation of JA ZIM-domain (JAZ) proteins, and activates the MYB transcription factors (such as MYB21 and MYB24) to regulate stamen development. In this study, we further uncover the mechanism underlying how MYB24 interacts with JAZs to control JA-regulated stamen development. We show that N-terminus of MYB21/24 interacts with 10 out of 12 JAZ proteins while both N-terminus and C-terminus of MYB24 are involved in dimerization of MYB21 and MYB24. Interestingly, male sterility of the JA-deficient mutant opr3 can be rescued by suitable level of the MYB24 overexpression but not by excessive high level of MYB24. Surprisingly, overexpression of MYB24NT, but not MYB24CT, could cause male sterility. These results provide new insights on MYB factors in JA-regulated stamen development

    Wheat Lodging Area Recognition Method Based on Different Resolution UAV Multispectral Remote Sensing Images

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    ObjectiveTo quickly and accurately assess the situation of crop lodging disasters, it is necessary to promptly obtain information such as the location and area of the lodging occurrences. Currently, there are no corresponding technical standards for identifying crop lodging based on UAV remote sensing, which is not conducive to standardizing the process of obtaining UAV data and proposing solutions to problems. This study aims to explore the impact of different spatial resolution remote sensing images and feature optimization methods on the accuracy of identifying wheat lodging areas.MethodsDigital orthophoto images (DOM) and digital surface models (DSM) were collected by UAVs with high-resolution sensors at different flight altitudes after wheat lodging. The spatial resolutions of these image data were 1.05, 2.09, and 3.26 cm. A full feature set was constructed by extracting 5 spectral features, 2 height features, 5 vegetation indices, and 40 texture features from the pre-processed data. Then three feature selection methods, ReliefF algorithm, RF-RFE algorithm, and Boruta-Shap algorithm, were used to construct an optimized subset of features at different flight altitudes to select the best feature selection method. The ReliefF algorithm retains features with weights greater than 0.2 by setting a threshold of 0.2; the RF-RFE algorithm quantitatively evaluated the importance of each feature and introduces variables in descending order of importance to determine classification accuracy; the Boruta-Shap algorithm performed feature subset screening on the full feature set and labels a feature as green when its importance score was higher than that of the shaded feature, defining it as an important variable for model construction. Based on the above-mentioned feature subset, an object-oriented classification model on remote sensing images was conducted using eCognition9.0 software. Firstly, after several experiments, the feature parameters for multi-scale segmentation in the object-oriented classification were determined, namely a segmentation scale of 1, a shape factor of 0.1, and a tightness of 0.5. Three object-oriented supervised classification algorithms, support vector machine (SVM), random forest (RF), and K nearest neighbor (KNN), were selected to construct wheat lodging classification models. The Overall classification accuracy and Kappa coefficient were used to evaluate the accuracy of wheat lodging identification. By constructing a wheat lodging classification model, the appropriate classification strategy was clarified and a technical path for lodging classification was established. This technical path can be used for wheat lodging monitoring, providing a scientific basis for agricultural production and improving agricultural production efficiency.Results and DiscussionsThe results showed that increasing the altitude of the UAV to 90 m significantly improved flight efficiency of wheat lodging areas. In comparison to flying at 30 m for the same monitoring range, data acquisition time was reduced to approximately 1/6th, and the number of photos needed decreased from 62 to 6. In terms of classification accuracy, the overall classification effect of SVM is better than that of RF and KNN. Additionally, when the image spatial resolution varied from 1.05 to 3.26 cm, the full feature set and all three optimized feature subsets had the highest classification accuracy at a resolution of 1.05 cm, which was better than at resolutions of 2.09 and 3.26 cm. As the image spatial resolution decreased, the overall classification effect gradually deteriorated and the positioning accuracy decreased, resulting in poor spatial consistency of the classification results. Further research has found that the Boruta-Shap feature selection method can reduce data dimensionality and improve computational speed while maintaining high classification accuracy. Among the three tested spatial resolution conditions (1.05, 2.09, and 3.26 cm), the combination of SVM and Boruta-Shap algorithms demonstrated the highest overall classification accuracy. Specifically, the accuracy rates were 95.6%, 94.6%, and 93.9% for the respective spatial resolutions. These results highlighted the superior performance of this combination in accurately classifying the data and adapt to changes in spatial resolution. When the image resolution was 3.26 cm, the overall classification accuracy decreased by 1.81% and 0.75% compared to 1.05 and 2.09 cm; when the image resolution was 2.09 cm, the overall classification accuracy decreased by 1.06% compared to 1.05 cm, showing a relatively small difference in classification accuracy under different flight altitudes. The overall classification accuracy at an altitude of 90 m reached 95.6%, with Kappa coefficient of 0.914, meeting the requirements for classification accuracy.ConclusionsThe study shows that the object-oriented SVM classifier and the Boruta-Shap feature optimization algorithm have strong application extension advantages in identifying lodging areas in remote sensing images at multiple flight altitudes. These methods can achieve high-precision crop lodging area identification and reduce the influence of image spatial resolution on model stability. This helps to increase flight altitude, expand the monitoring range, improve UAV operation efficiency, and reduce flight costs. In practical applications, it is possible to strike a balance between classification accuracy and efficiency based on specific requirements and the actual scenario, thus providing guidance and support for the development of strategies for acquiring crop lodging information and evaluating wheat disasters

    Dietary carbohydrate sources influence the growth performance, plasma biochemical parameters and expression of genes involved in glucose metabolism in juvenile Pelodiscus sinensis

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    An 8-week growth trial was conducted to investigate the influences of different dietary carbohydrate sources on growth performance, feed utilization, plasma biochemical parameters and expression of glucose metabolism-related genes in juvenile Chinese soft-shelled turtle, Pelodiscus sinensis. Five isonitrogenous (45 %) and isolipidic (8 %) experimental diets contained 17 % glucose, maltose, sucrose, pregelatinized cassava starch (α-starch) or cellulose, respectively. The results showed that α-starch significantly improved the weight gain rate and specific growth rate of P. sinensis compared to glucose, sucrose and cellulose. No significant difference existed in daily feed intake among all diets. However, turtles fed with cellulose showed a significantly higher feed conversion ratio than that in other treatments except for glucose group. Turtles fed with glucose showed significantly higher plasma glucose content than counterparts in sucrose, α-starch and cellulose treatments. While sucrose induced higher plasma cholesterol and triacylglycerol contents of turtles compared to glucose, maltose, sucrose and α-starch. The plasma insulin in α-starch group showed a higher level than that in glucose group. The glycolysis enzymes including glucokinase and pyruvate kinase in α-starch group exhibited higher mRNA levels than that in other diets, while the mRNA levels of gluconeogenesis enzymes in α-starch group were significantly lower than that in glucose group. The expressions of glycogen synthase and phosphorylase glycogen in glucose group were significantly up-regulated compared with sucrose, α-starch or cellulose groups. In summary, the poor insulin secretion and the up-regulated gluconeogenesis may account for the decreased growth in glucose diets. The most appropriate tested carbohydrate source was α-starch for juvenile P. sinensis based on its positive impacts on growth and metabolism of turtles
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