266 research outputs found
Density Dependence of Transport Coefficients from Holographic Hydrodynamics
We study the transport coefficients of Quark-Gluon-Plasma in finite
temperature and finite baryon density. We use AdS/QCD of charged AdS black hole
background with bulk-filling branes identifying the U(1) charge as the baryon
number. We calculate the diffusion constant, the shear viscosity and the
thermal conductivity to plot their density and temperature dependences.
Hydrodynamic relations between those are shown to hold exactly. The diffusion
constant and the shear viscosity are decreasing as a function of density for
fixed total energy. For fixed temperature, the fluid becomes less diffusible
and more viscous for larger baryon density.Comment: LaTeX, 1+33 pages, 6 figures, references adde
Growth disturbance of extracts from several crops straw (residue) on Ageratina adenophora and biological-control implications in hazardous weed invasion for eco-restoration
Laboratory biological simulation experiment was conducted to investigate growth disturbance of high, moderate, low concentration of aqueous extracts (i.e. the original extracts with a solid liquid ratio of 1:40 g mL-1 and its 5 times diluents and 25 times diluents) from several crops straw (residue) on Ageratina adenophora, a worldwide notorious invasive weed. The results showed: (a) aqueous extracts from several crops straw (residue) brought about different impacts on the single index for germination and growth of A. adenophora, e.g., high concentration of aqueous extracts from Brassica oleracea waste leaves showed a strong inhibition against the germination rate (GR) and germination index (GI) of A. adenophora, while high concentration of aqueous extracts from Vicia cracca straw showed a strong inhibition against radicle length (RL) and hypocotyl length (HL) of A. adenophora; (b) high concentration of aqueous extracts from B. oleracea waste leaves and high, moderate and low concentration of aqueous extracts from Oryza sativa straw and Triticum aestivum straw showed rather strong synthetic effects (inhibition) on GR and GI of A. adenophora, which could be chosen for the control over the seeds germination of A. adenophora; (c) high and moderate concentrations of aqueous extracts from V. cracca straw, high concentration of aqueous extracts from B. campestris waste leaves, and moderate and low concentrations of aqueous extracts from O. sativa straw and T. aestivum straw showed rather strong synthetic effects (inhibition) on RL and HL of A. adenophora, which could be selected as ideal materials for the control over the seedlings growth of A. adenophora; and (d) high concentrations of aqueous extracts from V. cracca straw, B. oleracea waste leaves and B. campestris waste leaves, and high, moderate and low concentrations of aqueous extracts from O. sativa straw and T. aestivum straw showed rather strong synthetic effects (inhibition) on GR, GI, RL and HL of A. adenophora, which could be selected as ideal materials for the control over the seeds germination and seedlings growth of A. adenophora. Thus, this study would provide a theoretic guidance and technical support for the resources utilization of crops straw (residue) and the prevention and control over invasive weeds as well. (C) 2013 Elsevier B.V. All rights reserved.Laboratory biological simulation experiment was conducted to investigate growth disturbance of high, moderate, low concentration of aqueous extracts (i.e. the original extracts with a solid liquid ratio of 1:40 g mL-1 and its 5 times diluents and 25 times diluents) from several crops straw (residue) on Ageratina adenophora, a worldwide notorious invasive weed. The results showed: (a) aqueous extracts from several crops straw (residue) brought about different impacts on the single index for germination and growth of A. adenophora, e.g., high concentration of aqueous extracts from Brassica oleracea waste leaves showed a strong inhibition against the germination rate (GR) and germination index (GI) of A. adenophora, while high concentration of aqueous extracts from Vicia cracca straw showed a strong inhibition against radicle length (RL) and hypocotyl length (HL) of A. adenophora; (b) high concentration of aqueous extracts from B. oleracea waste leaves and high, moderate and low concentration of aqueous extracts from Oryza sativa straw and Triticum aestivum straw showed rather strong synthetic effects (inhibition) on GR and GI of A. adenophora, which could be chosen for the control over the seeds germination of A. adenophora; (c) high and moderate concentrations of aqueous extracts from V. cracca straw, high concentration of aqueous extracts from B. campestris waste leaves, and moderate and low concentrations of aqueous extracts from O. sativa straw and T. aestivum straw showed rather strong synthetic effects (inhibition) on RL and HL of A. adenophora, which could be selected as ideal materials for the control over the seedlings growth of A. adenophora; and (d) high concentrations of aqueous extracts from V. cracca straw, B. oleracea waste leaves and B. campestris waste leaves, and high, moderate and low concentrations of aqueous extracts from O. sativa straw and T. aestivum straw showed rather strong synthetic effects (inhibition) on GR, GI, RL and HL of A. adenophora, which could be selected as ideal materials for the control over the seeds germination and seedlings growth of A. adenophora. Thus, this study would provide a theoretic guidance and technical support for the resources utilization of crops straw (residue) and the prevention and control over invasive weeds as well. (C) 2013 Elsevier B.V. All rights reserved
Inhibition of STAT3 signaling as critical molecular event in resveratrol-suppressed ovarian cancer cells
One-step fabrication of biocompatible chitosan-coated ZnS and ZnS:Mn2+ quantum dots via a γ-radiation route
Biocompatible chitosan-coated ZnS quantum dots [CS-ZnS QDs] and chitosan-coated ZnS:Mn2+ quantum dots [CS-ZnS:Mn2+ QDs] were successfully fabricated via a convenient one-step γ-radiation route. The as-obtained QDs were around 5 nm in diameter with excellent water-solubility. These QDs emitting strong visible blue or orange light under UV excitation were successfully used as labels for PANC-1 cells. The cell experiments revealed that CS-ZnS and CS-ZnS:Mn2+ QDs showed low cytotoxicity and good biocompatibility, which offered possibilities for further biomedical applications. Moreover, this convenient synthesis strategy could be extended to fabricate other nanoparticles coated with chitosan
Evaluation of Physicochemical and Antioxidant Properties of Peanut Protein Hydrolysate
Peanut protein and its hydrolysate were compared with a view to their use as food additives. The effects of pH, temperature and protein concentration on some of their key physicochemical properties were investigated. Compared with peanut protein, peanut peptides exhibited a significantly higher solubility and significantly lower turbidity at pH values 2–12 and temperature between 30 and 80°C. Peanut peptide showed better emulsifying capacity, foam capacity and foam stability, but had lower water holding and fat adsorption capacities over a wide range of protein concentrations (2–5 g/100 ml) than peanut protein isolate. In addition, peanut peptide exhibited in vitro antioxidant properties measured in terms of reducing power, scavenging of hydroxyl radical, and scavenging of DPPH radical. These results suggest that peanut peptide appeared to have better functional and antioxidant properties and hence has a good potential as a food additive
Chemical Composition and Antioxidant Activities of Broussonetia papyrifera Fruits
Fruits of Broussonetia papyrifera from South China were analyzed for their total chemical composition, and antioxidant activities in ethanol and aqueous extracts. In the fruit of this plant, the crude protein, crude fat and carbohydrates was 7.08%, 3.72% and 64.73% of dry weight, respectively. The crude protein, crude fat and carbohydrates were 15.71%, 20.51% and 36.09% of dry weight, respectively. Fatty acid and amino acid composition of the fruit were analyzed. Unsaturated fatty acid concentration was 70.6% of the total fatty acids. The percentage of the essential amino acids (EAAs) was 40.60% of the total amino acids. Furthermore, B. papyrifera fruit are rich in many mineral elements and vitamins. Total phenolic content was assessed using the Folin-Ciocalteau assay, whereas antioxidant activities were assessed by measuring the ability of the two extracts to scavenge DPPH radicals, inhibit peroxidation, and chelate ferric ions. Their reducing power was also assessed. Results indicated that the aqueous extract of B. papyrifera was a more potent reducing agent and radical-scavenger than the ethanol extract. GC–MS analysis of the ethanol extract showed the presence of some acid-containing compounds. The changes in total phenolic content and antioxidant capacity in B. papyrifera from four different regions grown under normal conditions were assessed. The antioxidant activity of different extracts was positively associated with their total phenolic content. These results suggest that the fruit of B. papyrifera could be used in dietary supplement preparations, or as a food additive, for nutritional gain, or to prevent oxidation in food products
Gelatin microparticles aggregates as three-dimensional scaffolding system in cartilage engineering
A three-dimensional (3D) scaffolding system for chondrocytes culture has been produced by agglomeration of cells and gelatin microparticles with a mild centrifuging process. The diameter of the microparticles, around 10 μ, was selected to be in the order of magnitude of the chondrocytes. No gel was used to stabilize the construct that maintained consistency just because of cell and extracellular matrix (ECM) adhesion to the substrate. In one series of samples the microparticles were charged with transforming growth factor, TGF-β1. The kinetics of growth factor delivery was assessed. The initial delivery was approximately 48 % of the total amount delivered up to day 14. Chondrocytes that had been previously expanded in monolayer culture, and thus dedifferentiated, adopted in this 3D environment a round morphology, both with presence or absence of growth factor delivery, with production of ECM that intermingles with gelatin particles. The pellet was stable from the first day of culture. Cell viability was assessed by MTS assay, showing higher absorption values in the cell/unloaded gelatin microparticle pellets than in cell pellets up to day 7. Nevertheless the absorption drops in the following culture times. On the contrary the cell viability of cell/TGF-β1 loaded gelatin microparticle pellets was constant during the 21 days of culture. The formation of actin stress fibres in the cytoskeleton and type I collagen expression was significantly reduced in both cell/gelatin microparticle pellets (with and without TGF-β1) with respect to cell pellet controls. Total type II collagen and sulphated glycosaminoglycans quantification show an enhancement of the production of ECM when TGF-β1 is delivered, as expected because this growth factor stimulate the chondrocyte proliferation and improve the functionality of the tissue.JLGR acknowledge the support of the Spanish Ministry of Education through project No. MAT2010-21611-C03-01 (including the FEDER financial support). The support of the Instituto de Salud Carlos III (ISCIII) through the CIBER initiative of the Networking Research Center on Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN) is also acknowledged
Therapy-induced tumour secretomes promote resistance and tumour progression.
Drug resistance invariably limits the clinical efficacy of targeted therapy with kinase inhibitors against cancer. Here we show that targeted therapy with BRAF, ALK or EGFR kinase inhibitors induces a complex network of secreted signals in drug-stressed human and mouse melanoma and human lung adenocarcinoma cells. This therapy-induced secretome stimulates the outgrowth, dissemination and metastasis of drug-resistant cancer cell clones and supports the survival of drug-sensitive cancer cells, contributing to incomplete tumour regression. The tumour-promoting secretome of melanoma cells treated with the kinase inhibitor vemurafenib is driven by downregulation of the transcription factor FRA1. In situ transcriptome analysis of drug-resistant melanoma cells responding to the regressing tumour microenvironment revealed hyperactivation of several signalling pathways, most prominently the AKT pathway. Dual inhibition of RAF and the PI(3)K/AKT/mTOR intracellular signalling pathways blunted the outgrowth of the drug-resistant cell population in BRAF mutant human melanoma, suggesting this combination therapy as a strategy against tumour relapse. Thus, therapeutic inhibition of oncogenic drivers induces vast secretome changes in drug-sensitive cancer cells, paradoxically establishing a tumour microenvironment that supports the expansion of drug-resistant clones, but is susceptible to combination therapy
Identification of Novel Mt-Guab2 Inhibitor Series Active against M. tuberculosis
Tuberculosis (TB) remains a leading cause of mortality worldwide. With the emergence of multidrug resistant TB, extensively drug resistant TB and HIV-associated TB it is imperative that new drug targets be identified. The potential of Mycobacterium tuberculosis inosine monophosphate dehydrogenase (IMPDH) as a novel drug target was explored in the present study. IMPDH exclusively catalyzes the conversion of inosine monophosphate (IMP) to xanthosine monophosphate (XMP) in the presence of the cofactor nicotinamide adenine dinucleotide (NAD+). Although the enzyme is a dehydrogenase, the enzyme does not catalyze the reverse reaction i.e. the conversion of XMP to IMP. Unlike other bacteria, M. tuberculosis harbors three IMPDH-like genes, designated as Mt-guaB1, Mt-guaB2 and Mt-guaB3 respectively. Of the three putative IMPDH's, we previously confirmed that Mt-GuaB2 was the only functional ortholog by characterizing the enzyme kinetically. Using an in silico approach based on designed scaffolds, a series of novel classes of inhibitors was identified. The inhibitors possess good activity against M. tuberculosis with MIC values in the range of 0.4 to 11.4 µg mL−1. Among the identified ligands, two inhibitors have nanomolar Kis against the Mt-GuaB2 enzyme
Differentiated embryonic chondrocyte-expressed gene 1 is associated with hypoxia-inducible factor 1α and Ki67 in human gastric cancer
- …