Thermal Contraction of Electrodeposited Bi/BiSb Superlattice Nanowires

The lattice parameter of Bi/BiSb superlattice nanowire (SLNW) has been measured using in situ high-temperature X-ray diffraction method. The single crystalline Bi/BiSb SLNW arrays with different bilayer thicknesses have been fabricated within the porous anodic alumina membranes (AAMs) by a charge-controlled pulse electrodeposition. Different temperature dependences of the lattice parameter and thermal expansion coefficient were found for the SLNWs. It was found that the thermal expansion coefficient of the SLNWs with a large bilayer thickness has weak temperature dependence, and the interface stress and defect are the main factors responsible for the thermal contraction of the SLNWs

Initial Growth of Single-Crystalline Nanowires: From 3D Nucleation to 2D Growth

The initial growth stage of the single-crystalline Sb and Co nanowires with preferential orientation was studied, which were synthesized in porous anodic alumina membranes by the pulsed electrodeposition technique. It was revealed that the initial growth of the nanowires is a three-dimensional nucleation process, and then gradually transforms to two-dimensional growth via progressive nucleation mechanism, which resulting in a structure transition from polycrystalline to single crystalline. The competition among the nuclei inside the nanoscaled-confined channel and the growth kinetics is responsible for the structure transition of the initial grown nanowires

Solvothermal synthesis and thermoelectric properties of indium telluride nanostring-cluster hierarchical structures

A simple solvothermal approach has been developed to successfully synthesize n-type α-In2Te3 thermoelectric nanomaterials. The nanostring-cluster hierarchical structures were prepared using In(NO3)3 and Na2TeO3 as the reactants in a mixed solvent of ethylenediamine and ethylene glycol at 200°C for 24 h. A diffusion-limited reaction mechanism was proposed to explain the formation of the hierarchical structures. The Seebeck coefficient of the bulk pellet pressed by the obtained samples exhibits 43% enhancement over that of the corresponding thin film at room temperature. The electrical conductivity of the bulk pellet is one to four orders of magnitude higher than that of the corresponding thin film or p-type bulk sample. The synthetic route can be applied to obtain other low-dimensional semiconducting telluride nanostructures

Herbal Medicines for Parkinson's Disease: A Systematic Review of Randomized Controlled Trials

OBJECTIVE: We conducted systematic review to evaluate current evidence of herbal medicines (HMs) for Parkinson's disease (PD). METHODS: Along with hand searches, relevant literatures were located from the electronic databases including CENTRAL, MEDLINE, EMBASE, CINAHL, AMED, PsycInfo, CNKI, 7 Korean Medical Databases and J-East until August, 2010 without language and publication status. Randomized controlled trials (RCTs), quasi-randomized controlled trials and randomized crossover trials, which evaluate HMs for idiopathic PD were selected for this review. Two independent authors extracted data from the relevant literatures and any disagreement was solved by discussion. RESULTS: From the 3432 of relevant literatures, 64 were included. We failed to suggest overall estimates of treatment effects on PD because of the wide heterogeneity of used herbal recipes and study designs in the included studies. When compared with placebo, specific effects were not observed in favor of HMs definitely. Direct comparison with conventional drugs suggested that there was no evidence of better effect for HMs. Many studies compared combination therapy with single active drugs and combination therapy showed significant improvement in PD related outcomes and decrease in the dose of anti-Parkinson's drugs with low adverse events rate. CONCLUSION: Currently, there is no conclusive evidence about the effectiveness and efficacy of HMs on PD. For establishing clinical evidence of HMs on PD, rigorous RCTs with sufficient statistical power should be promoted in future