Spin-glass properties of metallic nanoparticles conducted by quantum size effects

[[abstract]]Diamagnetic silver reveals spin-glass properties as the material is dispersed into nanoparticles embedded in dielectric media. Significant shifts of the transition temperature TSG toward high temperatures with the filling factor are observed during the zero-field-cooling process for the magnetic susceptibility χ(T) measurement. The diffused quantum-sphere model is exploited to calculate the susceptibility of nanoparticles containing even or odd numbers of electrons in terms of particle sizes, which manifests a paramagnetic Curie-like characteristic as the temperature rises above TSG. The partition function evaluated by the spin-glass magnetic-dipole interaction conducted by quantum size effects can successfully address the experimental data with good quantitative agreement.[[fileno]]2010122010112[[department]]物理

Microbial communities associated with anaerobic degradation of polybrominated diphenyl ethers in river sediment

AbstractBackground/purposePolybrominated diphenyl ethers (PBDEs) are extensively used as a class of flame retardants and have become ubiquitous environmental pollutants. We aimed to uncover the changes in microbial community with PBDE anaerobic degradation with and without zero-valent iron in sediment from the Erren River, considered one of the most heavily contaminated rivers in Taiwan.MethodsPBDE anaerobic degradation in sediment was analyzed by gas chromatography with an electron capture detector. Microbial community composition was analyzed by a pyrosequencing-based metagenomic approach.ResultsThe anaerobic degradation rate of BDE-209 was higher than BDE-28 in sediment; the addition of zero-valent iron enhanced the degradation rates of both. In total, 19 known bacterial genera (4 major genera: Clostridium, Lysinibacillus, Rummeliibacillus, and Brevundimonas) were considered PBDE degradation-associated bacteria (sequence frequency negatively correlated with PBDE remaining percentage) as were four known archaea genera (Methanobacterium, Methanosarcina, Methanocorpusculum, and Halalkalicoccus; sequence frequency positively correlated with PBDE remaining percentage).ConclusionThe composition of bacteria and that of archaea affected the anaerobic degradation of BDE-28 and BDE-209. The addition of zero-valent iron further decreased the archaea content to undetectable levels

Preparation of ZnO membrane by chemical bath deposition method via regulated acidity

In this study, the chemical bath deposition (CBD) method was used to deposit a ZnO membrane on an indium tin oxide glass substrate. The deposition reaction working temperature was 90°C and the temperature retaining deposition time was 60 min; NH4OH was used to control the pH value in the range 10~11, and after deposition, the specimen was thermally annealed in air. Annealing temperatures in the range of 100~500°C were adopted to investigate the thin-film growth behavior and the effect of processing temperature on the ZnO membrane performance during the annealing process. The process parameters related to the preparation of the ZnO membrane by CBD were the pH value, retaining temperature deposition time, working temperature for the deposition reaction, annealing thermal processing, and so on. Scanning electron microscopy (SEM) was used to observe and analyze the surface morphology and microstructure of the membrane cross section, and UV-Vis spectrometry was used to measure the optical transmission of the ZnO membrane in air at different annealing temperatures. We investigated the effects of different pH values on the growth of the ZnO membrane by CBD. The experimental results show that at a pH of 10.7, we can obtain a transparent and electrically conductive ZnO thin film with a thickness of 240 nm, which has very good optical transmission and high electrical mobility at an annealing temperature of 200°C. Keywords: Chemical bath deposition, ZnO membrane, pH valu

Randomized Study of Darbepoetin Alfa and Recombinant Human Erythropoietin for Treatment of Renal Anemia in Chronic Renal Failure Patients Receiving Peritoneal Dialysis

Background/PurposeDarbepoetin alfa can be administered less frequently than recombinant human erythropoietin (r-HuEPO) for the treatment of anemia in chronic renal failure (CRF) patients. We aimed to confirm that darbepoetin alfa at a reduced dosing schedule can safely maintain a target hemoglobin level in CRF patients undergoing peritoneal dialysis.MethodsForty-five PD patients receiving r-HuEPO were randomized in a 1:1 ratio to continue r-HuEPO or to change to darbepoetin alfa (open-label). Patients were maintained within a target range of hemoglobin for 5.5 months by adjusting the dose and then the frequency of darbepoetin alfa and r-HuEPO over the initial 4 months. The evaluation period was the final 1.5 months. A total of 37 patients completed the study.ResultsDuring the evaluation period, the hemoglobin of the darbepoetin alfa group was higher than that in the baseline period (10.46 ± 0.22 g/dL vs. 9.98 ± 0.18 g/dL, p < 0.05). Hemoglobin remained similar in the r-HuEPO group. The average dose in the darbepoetin alfa group was 93.0 μg/month, while the average dose in the r-HuEPO group was 18,339.9 units/month. The dosing frequency was less in the darbepoetin alfa group (3.9 times/month vs. 9.2 times/month). We divided the darbepoetin alfa group into low-dose (< 70 μg/month) and high-dose (≥ 70 μg/month) subgroups. The body weight in the high-dose group was higher than that in the low-dose group (66 ± 11 kg vs. 52 ± 4.4 kg, p < 0.01).ConclusionBoth darbepoetin alfa and r-HuEPO safely maintain hemoglobin levels within the target range in peritoneal dialysis patients

Sox10+ adult stem cells contribute to biomaterial encapsulation and microvascularization.

Implanted biomaterials and biomedical devices generally induce foreign body reaction and end up with encapsulation by a dense avascular fibrous layer enriched in extracellular matrix. Fibroblasts/myofibroblasts are thought to be the major cell type involved in encapsulation, but it is unclear whether and how stem cells contribute to this process. Here we show, for the first time, that Sox10+ adult stem cells contribute to both encapsulation and microvessel formation. Sox10+ adult stem cells were found sparsely in the stroma of subcutaneous loose connective tissues. Upon subcutaneous biomaterial implantation, Sox10+ stem cells were activated and recruited to the biomaterial scaffold, and differentiated into fibroblasts and then myofibroblasts. This differentiation process from Sox10+ stem cells to myofibroblasts could be recapitulated in vitro. On the other hand, Sox10+ stem cells could differentiate into perivascular cells to stabilize newly formed microvessels. Sox10+ stem cells and endothelial cells in three-dimensional co-culture self-assembled into microvessels, and platelet-derived growth factor had chemotactic effect on Sox10+ stem cells. Transplanted Sox10+ stem cells differentiated into smooth muscle cells to stabilize functional microvessels. These findings demonstrate the critical role of adult stem cells in tissue remodeling and unravel the complexity of stem cell fate determination

Microwave-Assisted Thermal Remediation of Diesel Contaminated Soil

Leakage of petroleum products, gasoline and diesel, at gas station had become one of major soil contamination sources in Taiwan. Total number of 154 petroleum contaminated gas stations was successively ascertained since the implementation of Soil and Groundwater Remediation Act in 2002. One of the contaminated gas stations, mainly diesel polluted, was studied for the feasibility of microwave-assisted thermal remediation. The average of total petroleum hydrocarbons (TPHt) in hotspot of this site was 2,845 mg/kg exceeding regulatory limit (1,000 mg/kg). According to the groundwater condition in the site, soil samples treated by microwave radiation with and without water as saturation and vadose zones were respectively tested in laboratory. The results show that a 12-min microwave energy can heat soil with water to reach 235°C and degrade its TPHt to 934 mg/kg; additionally, a 5 min microwave energy can heat soil without water to reach 220°C and degrade its TPHt to 520 mg/kg. Both soil samples passed TPHt regulatory limit and microwave remediation with fast and effective advantages for petroleum products contaminated soil was also verified