Poly(vinyl alcohol) (PVA)/zirconium oxide (ZrO2) composite nanofibers with a skin-core structure were prepared and the effect of ZrO2 particle content on uniform web formation was investigated. The optimized polymer concentration, tip to collector distance, and applied voltage for electrospinning were 11 wt%, 12 cm, and 20 kV, respectively. Skin-core PVA/ZrO2 composite nanofibers containing up to 12 wt% ZrO2 were successfully prepared, but it was difficult to obtain PVA/ZrO2 composite nanofiber webs via conventional electrospinning. Increasing the amount of ZrO2 caused the morphology of the PVA/ZrO2 composite nanofibers to become a non-uniform nanoweb with irregular nanofiber diameters. While it was difficult to obtain a uniform nanofiber web containing a content of ZrO2 over 6 wt% for conventional electrospinning, a more uniform nanofiber web could be obtained at up to 9 wt% ZrO2 using a skin-core dual nozzle. More uniform webs could also be obtained when ZrO2 was in the skin rather than the core. 相似文献
Journal of Crop Science and Biotechnology - Two domestic wheat varieties were grown in the growth chamber set at 17°C, 20°C, 23°C and 26°C on average after the emergence of... 相似文献
Anthocyanidins found in certain flowers have been shown to act as strong antioxidants in various systems, exhibiting multiple biological actions. The antioxidative effects of water extract and ethanolic extract of longan (Dimocarpus longan Lour.) flowers were evaluated by radical scavenging activity and compared to those of gallic acid, myricetin, and epigallocatechin gallate. In this study, the suppressive effects of longan flower extracts on nitric oxide and prostaglandin E2 production were investigated using a lipopolysaccharide-stimulated RAW 264.7 cell model. Abundant levels of phenolic compounds including flavonoids, condensed tannins, and proanthocyanidins were found in water or ethanolic extracts prepared from dried longan flowers. The antioxidative effect of longan flower extract was similar to the effect exhibited by pure antioxidants. Moreover, longan flower extract showed prominent inhibitory effects on prostaglandin E2 production. Significant concentration-dependent inhibition of nitric oxide production was detected when cells were cotreated with lipopolysaccharide and various concentrations of longan flower extracts. These inhibitory effects were further attributed to suppression of inducible nitric oxide synthase protein expression and not to reduced enzymatic activity. These results suggest that longan flower crude extracts, especially ethanolic extract, have antioxidant and anti-inflammatory effects, and the probable mechanism involves inhibition of inflammation by proanthocyanidins. Preliminary observations suggest that longan flower extract, especially alcoholic extract, could be another potential source of natural dietary antioxidant and anti-inflammatory agent. 相似文献
This study was conducted to evaluate the effect of nicotinic acid on plasma membrane integrity and fatty acid composition in frozen–thawed boar sperm. Boar semen was cryopreserved using freezing extender containing nicotinic acid (NA), then plasma membrane integrity, osmotic equilibration, lipid peroxidation and fatty acid were analysed. The plasma membrane integrity of frozen–thawed sperm was significantly higher in the 10 mM NA than in the 0 and 20 mM NA treatment groups (p < 0.05). Additionally, the osmotic equilibration ability was not different in treatment groups, but lipid peroxidation was significantly decreased in the 10 mM NA treatment group (p < 0.05). The saturated fatty acids were significantly decreased in the 10 mM NA treatment group, and C18:1n‐9, C18:2n‐6, C20:4n‐6, C22:5n‐6 and C22:6n‐3, and total polyunsaturated fatty acids (PUFAs) were significantly increased in the 10 mM NA treatment groups (p < 0.05). In summary, 10 mM NA improved plasma membrane integrity, inhibited lipid peroxidation and increased PUFAs in frozen–thawed boar sperm. These results suggest that NA may be useful to protect the plasma membrane and inhibit the loss of PUFAs for sperm cryopreservation in pigs. 相似文献
This study was conducted to evaluate the effects of dietary supplementation of Barodon, an anionic alkali mineral complex, on growth, feed utilization, humoral innate immunity and disease resistance of olive flounder. A basal experimental diet was used as a control and supplemented with 0.1, 0.2, 0.3, 0.4, or 0.5% Barodon. Triplicate groups of fish (26.4 ± 0.2 g) were fed one of the diets to apparent satiation twice daily for 10 wk. The growth performance was enhanced (P < 0.05) linearly and quadratically in fish fed diets containing Barodon compared with that in fish fed the control. Feed utilization was significantly improved by Barodon supplementation. Serum lysozyme and antiprotease activities were increased quadratically in Barodon fed groups. Also, significantly higher superoxide dismutase activity was found in Barodon‐fed fish. Dietary supplementation of 0.1–0.3% Barodon resulted in significant enhancement of fish disease resistance against Streptococcus iniae. The findings in this study indicate that dietary supplementation of Barodon can enhance growth, feed utilization, innate immunity, and disease resistance of olive flounder and that the optimum level seems to be 0.1% in diets. 相似文献
Butylated hydroxyanisole (BHA) is a synthetic phenolic compound consisting of a mixture of two isomeric organic compounds: 2-tert-butyl-4-hydroxyanisole and 3-tert-butyl-4-hydroxyanisole. We examined the effect of BHA against hydrogen peroxide (H2O2)-induced apoptosis in primary cultured mouse hepatocytes. Cell viability was significantly decreased by H2O2 in a dose-dependent manner. Additionally, H2O2 treatment increased Bax, decreased Bcl-2, and promoted PARP-1 cleavage in a dose-dependent manner. Pretreatment with BHA before exposure to H2O2 significantly attenuated the H2O2-induced decrease of cell viability. H2O2 exposure resulted in an increase of intracellular reactive oxygen species (ROS) generation that was significantly inhibited by pretreatment with BHA or N-acetyl-cysteine (NAC, an ROS scavenger). H2O2-induced decrease of cell viability was also attenuated by pretreatment with BHA and NAC. Furthermore, H2O2-induced increase of Bax, decrease of Bcl-2, and PARP-1 cleavage was also inhibited by BHA. Taken together, results of this investigation demonstrated that BHA protects primary cultured mouse hepatocytes against H2O2-induced apoptosis by inhibiting ROS generation. 相似文献
This study was designed to isolate bifidobacteria from human intestines that efficiently converts monolinolein, a monoglyceride form of linoleic acid, into conjugated linoleic acid (CLA), as well as to optimize culture conditions for improving CLA production during milk fermentation. Among 150 screened neonatal bifidobacteria, Bifidobacterium breve LMC 520 showed the highest CLA-producing ability and was tested with different types of fat substrates at various concentrations to determine the optimal conditions for CLA production. Monolinolein was tested as a substrate for CLA production. The incubation time optimized for CLA production was 24 h, and CLA production was proportionally increased with monolinolein concentration. The incubation of LMC 520 with commercial starter strains caused minimal reduction in CLA production. Our results demonstrate that the CLA-producing ability of B. breve LMC 520 could offer beneficial effects when utilized as a starter culture for the development of functional dairy products. 相似文献
Herbicide treatments in viticulture can generate highly contrasting mosaics of vegetated and bare vineyards, of which vegetated fields often provide better conditions for biodiversity. In southern Switzerland, where herbicides are applied at large scales, vegetated vineyards are limited in extent and isolated from one another, potentially limiting the distribution and dispersal ability of organisms.
Objectives
We tested the separate and interactive effects of habitat amount and fragmentation on invertebrate abundance using a multi-scale framework, along with additional environmental factors. We identified which variables at which scales were most important in predicting patterns of invertebrate abundance.
Methods
We used a factorial design to sample across a gradient of habitat amount (area of vegetated vineyards, measured as percentage of landscape PLAND) and fragmentation (number of vegetated patches, measured as patch density PD). Using 10 different spatial scales, we identified the factors and scales that most strongly predicted invertebrate abundance and tested potential interactions between habitat amount and fragmentation.
Results
Habitat amount (PLAND index) was most important in predicting invertebrate numbers at a field scale (50 m radius). In contrast, we found a negative effect of fragmentation (PD) at a broad scale of 450 m radius, but no interactive effect between the two.
Conclusions
The spatial scales at which habitat amount and fragmentation affect invertebrates differ, underpinning the importance of spatially explicit study designs in disentangling the effects between habitat amount and configuration. We showed that the amount of vegetated vineyards has more influence on invertebrate abundance, but that fragmentation also contributed substantially. This suggests that efforts for augmenting the area of vegetated vineyards is more beneficial for invertebrate numbers than attempts to connect them.