Firstly, constant amplitude P-Sa-Sm-Nc surface family is established. Secondly, four basic assumptions, i.e., monotonically increasing, non-coupling, separability and nonintersecting of fatigue damage accumulation are proposed from the viewpoint of both damage mechanics and fracture mechanics. Then the individual isodamage D-Sa-Sm-N surface under constant amplitude loading is constructed and the two-dimensional individual Miner‘s rule is derived. Consequently, the two-dimensional probabilistic Miner‘s rule (TPMiner) is established and proved for a population subjected to variable amplitude loading. Finally, with successfully experiment verification, TPMiner proves be to very useful and feasible in fatigue reliability theory.
A long-term experiment was conducted at the Ecological Experimental Station of Red Soil, Chinese Academy of Sciences to investigate the characteristics of material cycling and C, N accumulation in infertile red soil under different treatments of rotation systems for 11 years. Plant biomass, amount of organic materials returned to the soil, and budget of nitrogen in soil were obviously different under conventional cultivation, coverage by shrubs ( Lespedeza formosa ), rotation of shrubs ( Lespedeza formosa ) and crops (PeanutBuckwheat). Rotation of shrubs and crops with a combination of rational fertilization would be 75 - 100% of biomass and a similar amount of organic materials returned to the soil compared with that under coverage shrubs, more input than output of nitrogen, high system stability, and increasing crop productivity. With distinct cycling, different treatments of rotation systems influenced discriminatorily soil fertility. Soil organic carbon and nitrogen were respectively less than 7 and 0.6 g kg-1 for conventional cultivation, 9- 11 and 0.6-0.9 g kg-1 for rotation of shrubs and crops, 14 - 16 g kg-1 and more than 1 g kg-1 for coverage by shrubs after 11 years, which represent low, middle and high levels of upland red soil fertility at the current situation. It implied that with cultivation system and fertilization measures, the infertile red soil could have middle to high fertility after about 10 years rational utilization. Comparison of results from different treatments showed that a large loss of organic carbon and nitrogen was caused by soil erosion which resulted in a low level of C and N in upland red soil. It could be suggested that increasing carbon storage in infertile red soil would sequester a great amount of atmospheric CO2 and mitigate the global warming potentially.
To help reduce risks of heavy metal pollution, two pot experiments were conducted to investigate the variations, transfer potential, and stability of Cadmium （Cd） and Lead （Pb） accumulations in celery （Apium graveolens L.） and to screen for low Cd and Pb accumulative cultivars. The maximum differences in shoot Cd concentration were 4.7-fold under low-Cd exposure and 3.3-fold under high-Cd exposure. These genotype variations in Cd accumulation are sufficiently large to help reduce Cd contamination risk in soil by using the Low-Cd-Accumulative genotypes. Cd accumulation of the Low-Cd-Accumulative genotypes is significantly positive correlated with Pb accumulation. Evidence obtained proves that Cd and Pb accumulations in celery are stable and genotype-dependent at the cultivar level. The presence of high-Pb contamination in soil promoted Cd accumulation in shoots of celery. Celery is considered a species with high risks in Cd pollution and low risks in Pb pollution. Among the tested cultivars, cv. Shuanggang- kangbing （SGKB） had the lowest shoot Cd and Pb accumulating abilities, and thus is the most important material for breeding of pollution-safe cultivars （PSCs） to minimize Cd and Pb accumulations in celery.
AIM:To investigate the effects of the heme oxygenase(HO)-1/carbon monoxide system on iron deposition and portal pressure in rats with hepatic fibrosis induced by bile duct ligation(BDL).METHODS:Male Sprague-Dawley rats were divided randomly into a Sham group,BDL group,Fe group,deferoxamine(DFX) group,zinc protoporphyrin(ZnPP) group and cobalt protoporphyrin(CoPP) group.The levels of HO-1 were detected using different methods.The serum carboxyhemoglobin(COHb),iron,and portal vein pressure(PVP) were also quantified.The plasma and mRNA levels of hepcidin were measured.Hepatic fibrosis and its main pathway were assessed using Van Gieson’s stain,hydroxyproline,transforming growth factor-β1(TGF-β1),nuclear factor-E2-related factor 2(Nrf2),matrix metalloproteinase-2(MMP-2) and tissue inhibitor of metalloproteinase-1(TIMP-1).RESULTS:Serum COHb and protein and mRNA expression levels of HO-1 and Nrf2 were increased in the BDL group compared with the Sham group and were much higher in the CoPP group.The ZnPP group showed lower expression of HO-1 and Nrf2 and lower COHb.The levels of iron and PVP were enhanced in the BDL group but were lower in the ZnPP and DFX groups and were higher in the CoPP and Fe groups.Hepcidin levels were higher,whereas superoxide dismutase levels were increased and malonaldehyde levels were decreased in the ZnPP and DFX groups.The ZnPP group also showed inhibited TGF-β1 expression and regulated TIMP-1/MMP-2 expression,as well as obviously attenuated liver fibrosis.CONCLUSION:Reducing hepatic iron deposition and CO levels by inhibiting HO-1 activity though the Nrf2/Keap pathway could be helpful in improving hepatic fibrosis and regulating PVP.
AIM: To investigate long-term effects of Garcinia Cambogia (GC), weight-loss supplement, on adiposity and non-alcoholic fatty liver disease in obese mice. METHODS: Obesity-prone C57BL/6J mice were fed a high-fat diet (HFD, 45 kcal% fat) with or without GC (1%, w/w) for 16 wk. The HFD contained 45 kcal% fat, 20 kcal% protein and 35 kcal% carbohydrate. They were given free access to food and distilled water, and food consumption and body weight were measured daily and weekly, respectively. Data were expressed as the mean ± SE. Statistical analyses were performed using the statistical package for the social science software program. Student’s t test was used to assess the differences between the groups. Statistical significance was considered at P < 0.05. RESULTS: There were no significant changes in body weight and food intake between the groups. However, the supplementation of GC significantly lowered visceral fat accumulation and adipocyte size via inhibition of fatty acid synthase activity and its mRNA expression in visceral adipose tissue, along with enhanced enzymatic activity and gene expression involved in adipose fatty acid β-oxidation. Moreover, GC supplementation resulted in significant reductions in glucose intolerance and the plasma resistin level in the HFD-fed mice. However, we first demonstrated that it increased hepatic collagen accumulation, lipid peroxidation and mRNA levels of genes related to oxidative stress (superoxide dismutase and glutathione peroxidase) and inflammatory responses (tumor necrosis factor-α and monocyte chemoattractant protein-1) as well as plasma alanine transaminase and aspartate transaminase levels, although HFD-induced hepatic steatosis was not altered. CONCLUSION: GC protects against HFD-induced obesity by modulating adipose fatty acid synthesis and β-oxidation but induces hepatic fibrosis, inflammation and oxidative stress.
Hepatic steatosis defined as lipid accumulation in hepatocytes is very frequently found in adults andobese adolescents in the Western World. Etiologically,obesity and associated insulin resistance or excessalcohol intake are the most frequent causes of hepaticsteatosis. However, steatosis also often occurs withchronic hepatitis C virus （HCV） infection and is alsofound in rare but potentially life-threatening liverdiseases of pregnancy. Clinical significance andoutcome of hepatic triglyceride accumulation arehighly dependent on etiology and histological patternof steatosis. This review summarizes current conceptsof pathophysiology of common causes of hepaticsteatosis, including non-alcoholic fatty liver disease（NAFLD）, alcoholic fatty liver disease, chronic HCVinfections, drug-induced forms of hepatic steatosis,and acute fatty liver of pregnancy. Regarding thepathophysiology of NAFLD, this work focuses on theclose correlation between insulin resistance and hepatictriglyceride accumulation, highlighting the potentialharmful effects of systemic insulin resistance on hepaticmetabolism of fatty acids on the one side and the roleof lipid intermediates on insulin signalling on the otherside. Current studies on lipid droplet morphogenesishave identified novel candidate proteins and enzymesin NAFLD.
In this article,we investigated effects of lead and cadmium on the biomass of ginkgo seedlings, and roles of the seedlings in accumulation characteristics of the heavy metals and remediation of the soil contaminated by Cd2+ or Pb2+ as well as their combination.The results showed that both Cd2+ and Pb2+ significantly or very significantly reduced biomass increment of ginkgo seedlings,with Pb2+ more adverse than Cd2+.The Cd2+-Pb2+ compound pollution further reduced biomass increment of ginkgo seedlings.The mass fractions and enrichment coefficient of Pb2+ and Cd2+ in ginkgo seedlings were in an order of root>stem>leaf,which was in favor of transportation Pb2+ and Cd2+ from root to stem and leave.The Cd2+-Pb2+ compound pollution promoted ginkgo seedling absorption to Cd2+ and Pb2+.The capacity of the upward transport of Pb2+ was greater than that of Cd2+,which suggested an obvious dose-effect and synergistic effect.Cd2+ and Pb2+ accumulations in ginkgo seedlings were relatively large.The accumulation in roots was higher than that in stems and leaves.The ability of the absorption,transportation and accumulation of ginkgo seedlings to Pb2+ was relatively greater under Cd2+-Pb2+ compound pollution.The phytoremediation efficiency of Cd2+ and Pb2+ was relatively high.
High grain-Cd-accumulating rice variety Yongyou 9 was planted in Cd-contaminated farmland in Taizhou City,Zhejiang Province,China to study the effects of 5-aminolevulinic acid(ALA)and 24-epibrassinolide(EBR)on Cd accumulation in brown rice.Results showed that the exogenous ALA and EBR had no significant effects on agronomic traits,soil pH and total Cd content in soil,but had some effects on the available Cd content in soil,and significantly influenced the Cd accumulation in the different parts of rice.Results also showed that 100 mg/L exogenous ALA significantly reduced the Cd accumulation in brown rice to blow the food safety standard(0.2 mg/kg),and also significantly reduced the Cd contents in the roots and culm of rice.However,200 mg/L exogenous ALA treatment increased the Cd content in brown rice remarkably.In addition,0.15 mg/L EBR treatment increased Cd accumulation in roots,culm,leaves and brown rice notably,whereas 0.30 mg/L exogenous EBR treatment reduced the Cd accumulation in brown rice properly,but it was not significant.Therefore,proper concentration of ALA can effectively reduce the Cd accumulation in brown rice,which can be used as an effective technical method for the safe production of rice in Cd polluted farmland.
Lodging is the most important constraint for soybean growth at seedling stage in maize-soybean relay strip intercropping system. In the field experiments, three soybean cultivars Nandou 032-4 (shade susceptible cultivar;B1), Jiuyuehuang (moderately shade tolerant cultivar;B2), and Nandou 12 (shade tolerant cultivar;B3) were used to evaluate the relationship between stem stress and lignin metabolism in the stem of soybean. Results showed that the intercropped soybean was in variable light condition throughout the day time and co-growth stage with maize. The xylem area and cross section ratio played a main role to form the stem stress. The B3 both in intercropping and monocropping expressed a high stem stress with higher xylem area, lignin content, and activity of enzymes (phenylalanine ammonia-lyase (PAL), 4-coumarate: CoA ligase (4CL), cinnamyl alcohol dehydrogenase (CAD), and peroxidase (POD)) than those of B1 and B2. Among the soybean cultivars and planting pattern, lignin content was positively correlated with stem stress. However, a negative correlation was found between lignin content and actual rate of lodging. In conclusion, the shade tolerant soybean cultivar had larger xylem area, higher lignin content and activities of CAD, 4CL, PAL, and POD than other soybean cultivars in intercropping. The lodging in maize-soybean intercropping can be minimized by planting shade tolerant and lodging resistant cultivar of soybean. The lignin content in stem could be a useful indicator for the evaluation of lodging resistance of soybean in intercropping and activities of enzymes were the key factors that influence the lignin biosynthesis.
In the literature there are many reports on the composition and properties of pumpkin seed oil; however, few is known about the effect of different stages of seed development on various fatty acid profiles in developing seeds. The objective of this study was to provide the changes of various fatty acid accumulations in seed oil obtained from the seeds of three pumpkin varieties belonging to the species Cucurbita maxima and Cucurbita pepo. Unsaturated acids (oleic and linoleic) were dominant in various fatty acids, which constituted 38.9%-49.1% and 29.4%-42.7% of the total fatty acids at seed maturity for three pumpkin varieties, respectively, while other fatty acid concentrations except for palmitic acid all did not reach 10%. Different varieties exhibited greater effect on various fatty acid contents and the total fatty acid contents in the seeds of pumpkin rather than the species. On the whole, palmitic acid profiles of the seed oil in three varieties all followed the fluctuant decrease during all the stages of seed development, but palmitoleic acid and the total fatty acid profiles of the seed oil in three varieties were just the opposite. Stearic, oleic and linoleic acid profiles of the seed oil in three varieties all experienced the third pattern that fluctuated during all the stages of seed development, but no significant differences in these three fatty acid concentrations were found from the beginning to the end. Linolenic acid concentrations of three varieties were on the decline and ultimately close to zero. Myristic and arachidic acid profiles of the seed oil followed different trends in three varieties. Among them, myristic and arachidic acid profiles of the seed oil of Yinhui-1 fluctuated downward all the time until seed maturity, but those of 0238-1 and Jinhui-2 completely changed oppositely.