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991.
A pot experiment was conducted to study the performance of EDTA and citric acid (CA) addition in improving phytoextraction of Cd, Cu, Pb, and Cr from artificially contaminated soil by T. angustifolia. T. angustifolia showed the remarkable resistance to heavy metal toxicity with no visual toxic symptom including chlorosis and necrosis when exposed to metal stress. EDTA-addition significantly reduced plant height and biomass, compared with the control, and stunted plant growth, while 2.5 and 5 mM CA addition induced significant increases in root dry weight. EDTA, and 5 and 10 mM CA significantly increased shoot Cd, Pb, and Cr concentrations compared with the control, with EDTA being more effective. At final harvest, the highest shoot Cd, Cr, and Pb concentrations were recorded in the treatment of 5 mM EDTA addition, while maximal root Pb concentration was found at the 2.5 mM CA treatment. However, shoot Cd accumulation in the 10 mM CA treatment was 36.9% higher than that in 2.5 mM EDTA, and similar with that in 10 mM EDTA. Shoot Pb accumulation was lower in 10 mM CA than that in EDTA treatments. Further, root Cd, Cu, and Pb accumulation of CA treatments and shoot Cr accumulation in 5 or 10 mM CA treatments were markedly higher than that of control and EDTA treatments. The results also showed that EDTA dramatically increased the dissolution of Cu, Cr, Pb, and Cd in soil, while CA addition had less effect on water-soluble Cu, Cr, and Cd, and no effect on Pb levels. It is suggested that CA can be a good chelator candidate for T. angustifolia used for environmentally safe phytoextraction of Cd and Cr in soils.  相似文献   
992.
The production of L(+)-lactic acid (LA) by Rhizopus oryzae immobilized in polyvinyl alcohol (PVA) was investigated. To decrease diffusional resistance, we modified the PVA gel through the addition of sodium alginate and phosphate esterification. The production of L(+)-LA improved notably in the immobilized Rhizopus oryzae. Maximum L(+)-LA production (106.27 g/L), with a yield of 73.1 % and rate of 2.95 g/L·h, was obtained at a temperature of 38 °C, 6 % PVA, and 0.8 % sodium alginate. The immobilized R. oryzae was stable in 14 serial-batch cultures using non-growth medium. The immobilized beads also displayed good tolerance to low temperature and long-term storage at 4 °C with the preservation of biochemical properties.  相似文献   
993.
Development of the fluorescent pH detection method is promising due to the sensitivity, easy operation, and low‐cost, etc. However, traditional organic fluorophores have still some disadvantages such as the tedious preparation and purification as well as low photostability and water solubility, which limits the rapid detection application. Semiconductor quantum dots (QDs) have recently risen to prominence as an alternative for organic fluorophores in fluorescence analysis by virtue of their convenient synthesis and superior optical properties. In this study, we report on sodium 4‐mercaptophenolate functionalized CdSe/ZnS QDs (denoted as ?OPhS‐QDs), which can serve as a selective “on–off” fluorescence probe for aqueous media pH. ?OPhS‐QDs exhibit strong fluorescence in near neutral medium. As a Lewis organic base, ?OPhS‐ moieties on QDs surface easily binds to proton under acidic conditions to yield 4‐mercaptophenol capped QDs (i.e. HOPhS‐QDs), which acts as an efficient hole trapper. As a result, the QDs photoluminescence (PL) is switched off. Under optimal conditions, the present probe exhibits a good linear relationship between fluorescence response and pH values in the pH range 3.0–5.2. Furthermore, the present probe exhibits a high selectivity for proton over other common cations and has been successfully used for pH detection in real water samples.  相似文献   
994.
Myostatin is a negative regulator of skeletal muscle growth. Muscle tissue is the largest tissue in the body and influences body growth. Commercial Avian broiler chickens are selected for high growth rate and muscularity. Daweishan mini chickens are a slow growing small-sized chicken breed. We investigated the relations between muscle (breast and leg) myostatin mRNA expression and body and muscle growth. Twenty chickens per breed were slaughtered at 0, 30, 60, 90, 120, and 150 days of age. Body and muscle weights were higher at all times in Avian chickens. Breast muscle myostatin expression was higher in Avian chickens than in Daweishan mini chickens at day 30. Myostatin expression peaked at day 60 in Daweishan mini chickens and expression remained higher in breast muscle. Daweishan mini chickens myostatin expression correlated positively with carcass weight, breast and leg muscle weight from day 0 to 60, and correlated negatively with body weight from day 90 to 150, while myostatin expression in Avian chickens was negatively correlated with carcass and muscle weight from day 90 to 150. The results suggest that myostatin expression is related to regulation of body growth and muscle development, with two different regulatory mechanisms that switch between days 30 and 60.  相似文献   
995.
The Sika deer antler is well known for its unique ability to regenerate repeatedly and grow rapidly. Furthermore, it is a precious traditional Chinese medicine and has been widely used for more than 20 centuries. The major bioactive components within the antlers are water-soluble proteins, polypeptides, and free amino acids. Many studies have shown that water-soluble antler extracts play pivotal roles in wound healing, immune system modulation, anti-oxidation, and anti-inflammation. However, the exact effects on chondrocytes are still largely unknown. In this study, we prepared fresh, aqueous extracts from growing deer antlers in a rapid growth stage. We isolated the chondrocytes from neonatal mouse rib cartilage and investigated the effects of antler extracts on chondrocyte viability. We also used the RNA-Seq method to analyze the gene expression pattern under antler extract treatment. We demonstrated that fresh extracts from Sika deer antlers in a rapid growth stage significantly promoted chondrocyte viability and kept chondrocytes proliferating continuously, while blocking maturation and further differentiation. Additionally, our results indicated that antler extracts might serve as a potent anti-oxidant, anti-inflammatory agent, and immune modulator to boost the abilities of chondrocytes against oxidative, inflammatory, and immune stresses. Thus, this study has greatly deepened our current knowledge of the molecular control of antler extracts on chondrocytes. It has also shed light on possible new strategies to further prevent and treat diseases of cartilage and other related diseases.  相似文献   
996.
To explore the effect of ultra-strong static magnetic field on gut microbiota, 16 T static magnetic field was used to study the changes in the structure and composition of human and mouse gut microbiota in this environment. In the mouse gut microbiota, at the genus level, the magnetic field significantly decreased the relative abundances of Escherichia-Shigella, Lactobacillus, Enterococcus, Burkholderia-Caballeronia-Paraburkholderia, Parasutterella, and Ralstonia and significantly increased those of Parabacteroides, Alloprevotella, Alistipes, Odoribacter, Bacteroides, Mucispirillum, Sutterella, and Prevotellaceae_UCG-001. Similarly, at the genus level, the relative abundances of Bacteroides, Parabacteroides, Romboutsia, and Streptococcus significantly decreased in the human gut microbiota. Contrary to the changing trend of the abundance in the mouse gut, the abundances of Bacteroides and Parabacteroides in the human gut were significantly reduced under magnetic field. The BugBase phenotypic prediction analysis showed that the relative abundances of five phenotypes, including anaerobism, mobile elements, potential pathogenicity, stress-tolerant, and biofilm formation, changed significantly in the mouse gut microbiota, while the relative abundances of two phenotypes, including Gram-positive and Gram-negative phenotypes, changed significantly in the human gut microbiota. The 16 T magnetic field could differently affect the composition, structure, and phenotypes of gut microbiota in human and mice, suggesting the importance of model selection in studying the biological effects of magnetic field.  相似文献   
997.
Solution‐processed perovskite solar cells have great potential for low‐cost roll‐to‐roll fabrication. However, the degradation of aged precursor solutions will become a critical obstacle to mass production. In this report, a small molecule (ITIC‐Th) is employed to stabilize the perovskite precursor solution containing mixed cations and halides. It is found that ITIC‐Th can effectively suppress the formation of yellow δ‐phase in the films made from aged precursor solutions. Consequently, the devices fabricated from the aged precursor solution with ITIC‐Th experience much less efficiency drop with the increase of the precursor aging time—from 19.20% (fresh) to 16.55% (39 d), compared with the devices made from conventional precursor solutions dropping from 18.07% (fresh) to 1.76% (39 d). The characterizations suggest that ITIC‐Th is beneficial for CH3NH3+ cations to be incorporated into the crystal structure, facilitating the formation of perovskite phase. Furthermore, the presence of ITIC‐Th in the perovskite thin film gives rise to additional photocurrent as well as improved fill factor due to the well‐matched energy levels, the passivation of defects, and the complementary absorption spectra, suggesting a new route toward future high‐efficiency solar cells—incorporating organic non‐fullerene acceptors and halide perovskite materials into the same active layer.  相似文献   
998.
目的:探讨一种新型一体化防护服(IPS)的抗荷性能.方法:在离心机上首先测定10名受试者的基础 Gz耐力,然后受试者穿IPS充气,测此时的松弛耐力,两者之差即为IPS的抗荷性能.结果:受试者穿IPS时的松弛耐力明显高于基础耐力(P<0.01),其抗荷性能达到(2.38±0.38)G.结论:IPS的抗荷性能较好,可满足我国高性能战斗机的需要.  相似文献   
999.
Increasing evidence has demonstrated that the senescence of vascular endothelial cells (VECs) has critical roles in the pathogenesis of vascular dysfunction. Finding important factors that regulate VEC senescence will help provide novel therapeutic strategies for vascular disorders. Previously, we found that integrin β4 was involved in VEC senescence. However, the mechanism underlying VEC senescence mediated by integrin β4 remains poorly understand. In this study, we used a mouse in vivo model and showed that the level of integrin β4 in the endothelium of mouse thoracic aorta was increased during natural aging and atherosclerosis. Furthermore, we found that H‐ras, caveolin‐1, and AP‐1 were implicated in the senescent signal pathway mediated by integrin β4 in human umbilical vein ECs (HUVECs). Knockdown of integrin β4 could attenuate HUVEC senescent features, including increased interleukin‐8 (IL‐8) release and decreased endothelial nitric oxide synthase (eNOS) and NO levels and mitochondrial membrane potential in vitro. Our findings provide new clues illustrating the mechanism of VEC senescence. Integrin β4 might be a potential target for therapy in cardiovascular diseases. J. Cell. Physiol. 225: 673–681, 2010. © 2010 Wiley‐Liss, Inc.  相似文献   
1000.
The metabotropic glutamate receptor (mGluR) agonist (R,S)-3,5-dihydroxyphenylglycine (DHPG) is involved in several forms of hippocampal synaptic plasticity. DHPG application can induce slow-onset potentiation, a form of long-term potentiation (LTP), in the dentate gyrus and in the CA1 region in vivo. The induction of LTP correlates with increased expression levels of neuronal calcium sensor (NCS), considered as key elements for plasticity. In this study we investigated mGluR- and time-dependent changes in the expression of two different NCS proteins. Following DHPG application in vivo NCS-1 and VILIP-1 expression increased, with significant levels reached after 8 and 24h. The effect was attenuated by treatment with the group I mGluR specific antagonist S-4-carboxyphenylglycine. The immediate early gene (IEG) arg3.1/arc showed highest expression levels 2h after DHPG-treatment. Therefore, mGluRs at concentrations which induce synaptic plasticity regulate the expression of IEGs and NCS proteins in different time frames and thus contribute to late phases of synaptic plasticity.  相似文献   
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