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The preconditioned density-based algorithm and two-domain approach were used to investigate the fluid flow and heat transfer characteristics in a channel with staggered porous/solid ribs. In the porous zone, the momentum equations were formulated by the Darcy–Brinkman–Forchheimer model; and the local thermal equilibrium (LTE) model was adopted for energy equation. At the porous/fluid interface, the stress–continuity interfacial condition was utilized. The governing equations are solved by the preconditioned density-based control-volume method, with preconditioning matrix for equations of porous domain adopted, aiming to eliminate the equation stiffness of the porous seepage flow. The effects of Reynolds number, geometry parameters of ribs (rib length and thickness), and physical property of porous media (permeability and porosity) on the flow pattern and heat transfer performance were analyzed. Results indicate that, compared with that of solid ribs, the recirculating bubble behind the porous ribs is completely detached from it because of the permeability of porous media, and the size of the recirculating bubble is suppressed. The parameters that would affect the mass flow of fluid penetrating the porous ribs, including permeability, Reynolds number, baffle length and thickness, have remarkable influence on the flow pattern. All the aforementioned parameters would affect the local heat transfer performance. [ABSTRACT FROM AUTHOR]

The preconditioned density-based algorithm and two-domain approach were used to investigate the laminar-plate transpiration cooling process. In the porous zone, the momentum equations were formulated by the Darcy-Brinkman-Forchheimer model; and the local thermal equilibrium model (LTE) was adopted for the energy equation. At the porous/fluid interface, the stress-continuity interfacial condition was utilized. The effects of coolant injection rate, Reynolds number, pressure gradient of mainstream, and thermal conductivity ratio on the transpiration cooling performance were studied. Results indicate that the thickness of the coolant boundary layer on the protected surface has a significant effect on the transpiration cooling effect. Under the current conditions, the transpiration cooling performance would be enhanced with increasing coolant injection rate, but would be weakened with increasing Re. The adverse pressure gradient of mainstream would improve the transpiration cooling performance. [ABSTRACT FROM AUTHOR]

A preconditioned density-based finite-volume method is proposed to simulate the coupled fluid flow and heat transfer problems in hybrid porous/fluid/solid domains. In the porous zone, the momentum equation is formulated by the Darcy-Brinkman-Forchheimer model; and the thermal nonequilibrium model is adopted for the energy equation. At the porous/fluid interface, both the stress-jump and stress-continuity models are applied for interfacial hydrodynamic conditions. The preconditioning method for solving the flow equation of porous domain is developed, aiming to eliminate the stiffness of the equation for porous seepage flows. Three test cases in hybrid porous/fluid and porous/solid domains are presented to demonstrate the applicability and accuracy of the numerical algorithm. [ABSTRACT FROM AUTHOR]

1. The influence of dietary conjugated linoleic acid (CLA) on the antioxidant status in the absence or presence of endotoxin exposure was studied with male broiler chicks. 2. In experiment 1, a total of 240 1-d-old broilers were allotted into 4 dietary groups (0, 2·5, 5·0 or 10·0 g pure CLA/kg) to study the influence of CLA on growth performance and antioxidant defence systems. The results showed that growth performance was not altered by 42 d of CLA consumption. Increased total superoxide dismutase (TSOD) activities in liver, serum and muscle were observed in chicks given 10·0 g CLA/kg diet. Dietary CLA at 10·0 g/kg also markedly elevated liver catalase (CAT) activity. Malondialdehyde (MDA), a marker of lipid peroxidation, decreased in liver, serum and muscle in chicks given 5·0 and 10·0 g CLA/kg diet. 3. In experiment 2, a total of 120 1-d-old broilers were fed on a control diet (without CLA) or 10·0 g CLA/kg diet. Half of the birds fed on each diet were injected intraperitoneally with 0·25 mg/kg body weight of Salmonella enteritidis lipopolysaccharide (LPS) at 16, 18 and 20 d of age. Decreased glutathione peroxidase (GSH-Px), TSOD activity and increased ceruloplasmin and MDA concentrations were seen in the challenged chicks. Dietary CLA prevented the loss of body weight gain and feed conversion ratio of chicks followed repeated endotoxin exposure. CLA partially inhibited the increase of serum ceruloplasmin and MDA at 17 and 21 d of age and notably suppressed the decrease of serum TSOD activity at 21 d of age. 4. These results suggested that dietary CLA enhances the activity of antioxidant enzymes including TSOD and CAT. Supplementation of CLA has been shown to ameliorate the antioxidant balance and performance of chicks during oxidative stress. [ABSTRACT FROM AUTHOR]

This paper aims to develop an approximate mechanics model to predict the forces in the orthogonal cutting of unidirectional fibre-reinforced plastics when the fibre-orientation varies from 0° to 90°. Based on the experimental understanding achieved, the model divides the cutting zone into three characteristic regions, i.e., chipping, pressing and bouncing regions. The cutting tool geometry, such as the rake angle and nose radius, is considered. It shows that the model developed has captured the major deformation mechanisms in cutting the composites and can predict the cutting forces with acceptable accuracy. [ABSTRACT FROM AUTHOR]

1. A 2 × 2 factorial design was used to investigate the differences in carcase, muscle and meat characteristics between fast and slow growing genotypes fed on low nutrient (LND) or high nutrient diets (HND) at their respective slaughter ages. 2. The birds were randomly assigned to treatments with 5 replicates of 145 birds for Wens Yellow-Feathered Chicken (WYFC, 5·75 birds/m2) or 115 birds for White Recessive Rock Chicken (WRRC, 7·25 birds/m2), according to the commercial recommendations for the two breeds and were fed on HND or LND. Birds were slaughtered at 63 d and 105 d of age. 3. The results showed WRRC had higher carcase yield and meat yield than that of WYFC, lower fat content, higher moisture content and lower cooking loss. The meat from WRRC was less tender and contained lower levels of polyunsaturated fatty acids (PUFA). 4. Birds fed on HND had higher breast meat yield, myofiber area and protein content in the breast muscle and lower fat content than birds fed on LND. The thigh muscle of birds fed on HND had higher levels of PUFA. Age had a positive effect on carcase parameters, but a negative effect on pH, meat tenderness and cooking loss, and the two genotypes exhibited different responses to the influence of nutrient density and age. 5. Genotype and age had the largest effect on carcase performance and meat quality. LND benefited meat quality and WRRC had larger responses in meat yield and shear force when fed on HND. [ABSTRACT FROM PUBLISHER]

Context: Whether natural product drug discovery programs should rely on wild plants collected 'randomly' from the natural environment, or whether they should also include plants collected on the basis of use in traditional medicine remains an open question. Objective: This study analyzes whether plants with ethnomedical uses from Vietnam and Laos have a higher hit rate in bioassay testing than plants collected from a national park in Vietnam with the goal of maximizing taxonomic diversity ('random' collection). Materials and Methods: All plants were extracted and subjected to bioassay in the same laboratories. Results of assays of plant collections and plant parts (samples) were scored as active or inactive based on whether any extracts had a positive result in a bioassay. Contingency tables were analyzed using χ2 statistics. Results: Random collections had a higher hit rate than ethnomedical collections, but for samples, ethnomedical plants were more likely to be active. Ethnomedical collections and samples had higher hit rates for tuberculosis, while samples, but not collections, had a higher hit rate for malaria. Little evidence was found to support an advantage for ethnomedical plants in HIV, chemoprevention and cancer bioassays. Plants whose ethnomedical uses directly correlated to a bioassay did not have a significantly higher hit rate than random plants. Discussion: Plants with ethnomedical uses generally had a higher rate of activity in some drug discovery bioassays, but the assays did not directly confirm specific uses. Conclusions: Ethnomedical uses may contribute to a higher rate of activity in drug discovery screening. [ABSTRACT FROM AUTHOR]

The protonated imidazole diphosphopentamolybdenum polyoxometalate (C 4 H 7 N 2 ) 4 [HP 2 Mo 5 O 23 ]·H 3 O· 4.5H 2 O has been synthesized and its structure has been determined by single-crystal X-ray diffraction. This compound crystallizes in the triclinic crystal system, space group P (-1), a = 10.171(2), b = 11.839(2), c = 20.170(4) Å, α = 75.69(3), β = 84.56(3), γ = 64.90(3)°, V = 2130.8(7) Å 3 , Z = 2 and R = 0.0329. The compound is composed of [HP 2 Mo 5 O 23 ] 5- clusters and and H 3 O + cations as well as water of crystallization, and forms a supramolecular network structure through hydrogen bonds. The monoprotonated polyanions are held together by two strong hydrogen bonds [ d O…O = 2.582(7) and 2.581(8) Å]. Density functional theory (DFT) calculation has been carried out to investigate the electronic properties of the [H n P 2 Mo 5 O 23 ] (6- n )- ( n = 0, 1, 2) polyanions. Mulliken charges for all atoms have been analyzed. The results show that the negative charges delocalize over all types of oxygen atoms, and molybdenum and phosphorus atoms accept electrons from the oxygen atoms. The protonation affects the charge distribution, redox properties and relative stability of the polyanion; the non-protonated polyanion [P 2 Mo 5 O 23 ] 6- can be more easily reduced. [ABSTRACT FROM AUTHOR]

Large NdP 5 O 14 crystal with dimension of 15 × 25 × 60 mm 3 has been grown by flux method. The spontaneous strains and ferroelastic domain structures have been investigated by high resolution X-ray diffractometry for the first time. The reflection peak separations resulting from the misorientation between matrix domain and ferroelastic domain were observed in the rocking curves for several different reflections. Based on the features of the reflection peak separations, the ferroelastic domain structures were determined. It is found that most of the ferroelastic domains in NdP 5 O 14 are of type-a, while type-b ferroelastic domains only appear in the serious strain regions. Based on the domain structures of NdP 5 O 14 , the reflection peak separations for 802, 402 and 204 reflections were calculated respectively. And the experimental observations are in agreement with the calculations very well. In addition, the spontaneous strain in NdP 5 O 14 was determined to be 0.0082 by measuring the peak separation between two 800 diffraction from the matrix domain and the ferroelastic domain respectively. A detailed discussion on domain structures in the crystal is given in terms of structural and symmetric analyses. [ABSTRACT FROM AUTHOR]