4,004 research outputs found
Evaluation of elephant grass, vacuum compressed in horizontal silos, using heifers in an automated feeding system
Com o propósito de avaliar a eficiência do acondicionamento a vácuo do capim-elefante (Pennisetum purpureum Schum.) em silos de superfÃcie, comparou-se este sistema com o sistema de compactação a trator. Utilizaram-se novilhas mestiças Holandês-Zebu alimentadas exclusivamente com silagem em sistema contÃnuo de auto-alimentação. Não se observaram diferenças no consumo de nutrientes das silagens, no ganho de peso e no comportamento das novilhas sob estes sistemas.In order to evaluate the efficiency of vacuum compressing of elephant grass (Pennisetum pupureum Schum, in horizontal silos, this system was compared with that of compression by tractor. Mixed Holstein-Friesan-Zebu heifers fed exclusively on silage in continuous automated feeding system were used. Neither differences in the nutritive value of the silages, weight gain nor animal behavior were observed in heifers using these systems
Comparative efficacy of the conventional and automated methods for determining neutral and acid detergent fiber
Different methods are available to determine fiber content in feeds. However, information about the accuracy of this methods for neutral detergent fiber (NDF) and acid detergent fiber ADF contents estimation (obtained with the use of TNT-100 nylon filtering bags) is very limited related to the large number of ruminant feed analysis. The purpose of this study was to compare the efficacy of the automated and conventional Van Soest methods to determine NDF and ADF contents for bovine cattle and feed supplements. Four classes of samples (tropical forage, maize silage hybrid, concentrated supplements and bovine cattlecattle) were evaluated for NDF and ADF contents using conventional and automated methods. Analysis involved a hierarchical factorial scheme with an entirely randomized design executed with repetitions. It was concluded that the automated method procedure generated similar results when compared to the conventional method for the determination of NDF contents in tropical forage, bovine cattle and maize silage samples, although is not recommended for samples with a high starch content. This system was not efficient for ADF determination in the evaluated samples.Different methods are available to determine fiber content in feeds. However, information about the accuracy of this methods for neutral detergent fiber (NDF) and acid detergent fiber ADF contents estimation (obtained with the use of TNT-100 nylon filtering bags) is very limited related to the large number of ruminant feed analysis. The purpose of this study was to compare the efficacy of the automated and conventional Van Soest methods to determine NDF and ADF contents for bovine cattle and feed supplements. Four classes of samples (tropical forage, maize silage hybrid, concentrated supplements and bovine cattlecattle) were evaluated for NDF and ADF contents using conventional and automated methods. Analysis involved a hierarchical factorial scheme with an entirely randomized design executed with repetitions. It was concluded that the automated method procedure generated similar results when compared to the conventional method for the determination of NDF contents in tropical forage, bovine cattle and maize silage samples, although is not recommended for samples with a high starch content. This system was not efficient for ADF determination in the evaluated samples
Phytochemical screening, cytotoxicity and acute toxicity of Annona vepretorum Mart (Annonaceae) leaf extracts
Purpose: To investigate the phytochemistry, cytotoxicity and acute toxicity of leaf extracts from Annona vepretorum.Methods: The crude extracts were obtained by maceration with hexane and methanol. The crude methanol extract was suspended in a 3:7 (v/v) mixture of methanol (MeOH) and water (H2O) and partitioned with hexane, chloroform (CHCl3) and ethyl acetate (AcOEt) in ascending order of polarity to obtain the respective extracts. In the investigation of phytochemical profile, the extracts were evaluated on thin layer chromatography (TLC) plates of silica gel. Cytotoxicity was tested using 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) and (3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium) (MTS) assays against tumor cell lines, viz,HCT-116 (colon), SF-295 (brain), HL-60 (leukemic) and Sarcoma-180. Acute toxicity study was performed by administration of a single oral dose of 2 g/kg body weight of the extracts to mice and the animals were observed for 14 days.Results: Phytochemical screening results showed that A. vepretorum extracts contain alkaloids, flavonoids and terpenes. Methanol and chloroform extracts exhibited high cytotoxic activity against HCT-116, HL-60 and Sarcoma-180. Moreover, the extracts displayed low toxicity in mice, as no deaths and pronounced toxic effects were observed.Conclusion: A. vepretorum contains a variety of secondary metabolites which may confer on this species high cytotoxic activity. In addition, the oral administration of the extracts produced low toxicity in mice.Keywords: Annonaceae, Annona vepretorum, Phytochemistry, Tumor cell lines, Acute toxicit
Flavonoids: Promising Natural Products for Treatment of Skin Cancer (Melanoma)
Melanoma, which is the most malignant skin cancer type, has got one of the fastest increasing incidence rates of all cancer types in the world. When belatedly diagnosed, melanoma is extremely invasive and metastatic. Although there are effective drugs used to treat melanoma, some cell lines have proven resistant to chemotherapy. In this context, several research groups on natural products have investigated the anticancer effect of new natural molecules in the treatment of melanoma. Flavonoids have shown to play an important role in chemoprevention and inhibition of the proliferation, migration, and invasion of melanoma cells. In this chapter, we present a systematic review performed through a literature search over a period of 20 years, using specialized databases. Analysis of all selected manuscripts demonstrated that at least 97 flavonoids have already been investigated for the treatment of melanoma using in vitro or in vivo models. Most of the bioactive flavonoids belong to the classes of flavones (38.0%), flavonols (17.5%), or isoflavonoids (17.5%). Apigenin, diosmin, fisetin, luteolin, and quercetin were considered as the most studied flavonoids for melanoma treatment. In general, flavonoids have shown to be a promising source of molecules with great potential for the treatment of melanoma
Reverse and Forward Engineering of Local Voltage Control in Distribution Networks
The increasing penetration of renewable and distributed energy resources in
distribution networks calls for real-time and distributed voltage control. In
this paper we investigate local Volt/VAR control with a general class of
control functions, and show that the power system dynamics with non-incremental
local voltage control can be seen as distributed algorithm for solving a
well-defined optimization problem (reverse engineering). The reverse
engineering further reveals a fundamental limitation of the non-incremental
voltage control: the convergence condition is restrictive and prevents better
voltage regulation at equilibrium. This motivates us to design two incremental
local voltage control schemes based on the subgradient and pseudo-gradient
algorithms respectively for solving the same optimization problem (forward
engineering). The new control schemes decouple the dynamical property from the
equilibrium property, and have much less restrictive convergence conditions.
This work presents another step towards developing a new foundation -- network
dynamics as optimization algorithms -- for distributed realtime control and
optimization of future power networks
Adaptabilidade e estabilidade de cultivares de milho para silagem em relação à produção de matéria seca degradável no rúmen
CHEMICAL CHANGES IN BEAN GRAINS DURING STORAGE IN CONTROLLED CONDITIONS
Banjarmasin, Borneo (Kalimantan, Indonesia) 195-GrayscaleForman Safety Negatives, Box
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