Effect of H2 on the Electrical Transport Properties of Single Bi2S3 Nanowires

Field effect transistors have been fabricated using Bi2S3 nanowires. Whether the contact is ohmic or non-ohmic, the current of Bi2S3 nanowires was found to increase remarkably in H2 compared to that in a vacuum. Carrier density and mobility within the nanowires and the contact barriers between the nanowires and the electrodes have been extracted using field effect and two-probe current-voltage curves. It was found that H2 enhances electronic mobility and carrier density within the nanowires dramatically. The effect of H2 on the contact barriers was observed to be negligible compared to the other two effects.

Fermented papaya preparation attenuates beta-amyloid precursor protein: beta-amyloid-mediated copper neurotoxicity in beta-amyloid precursor protein and beta-amyloid precursor protein Swedish mutation overexpressing SH-SY5Y cells

Recent studies indicate that the deposition of beta-amyloid (Abeta) is related in the pathogenesis of Alzheimer's disease (AD), but the underlying mechanism is still not clear. The abnormal interactions of Abeta with metal ions such as copper are implicated in the process of Abeta deposition and oxidative stress in AD brains. In the present study, we established a new AD model, using which we found that copper triggered the Abeta neurotoxicity in SH-SY5Y cells overexpressing the Swedish mutant form of human APP (APPsw) in a concentration dependent manner. Fermented papaya preparation (FPP) has shown high free radical scavenging ability in vivo and in vitro. FPP post-treatment increased cell viability and decreased the intracellular [Ca2+]i, reactive oxygen species (ROS) generation such as hydroxyl free radical and superoxide anion and nitric oxide (NO) accumulation in the cell. Our results also show that FPP prevents the cell apoptosis through bax/bcl-2 sensitive pathway.

Regulation of synaptic input to hypothalamic presympathetic neurons by GABA(B) receptors

The hypothalamic paraventricular (PVN) neurons projecting to the spinal cord and brainstem play an important role in the control of homeostasis and the sympathetic nervous system. Although GABA(B) receptors are present in the PVN, their function in the control of synaptic inputs to PVN presympathetic neurons is not clear. Using retrograde tracing and whole-cell patch-clamp recordings in rat brain slices, we determined the role of presynaptic GABA(B) receptors in regulation of glutamatergic and GABAergic inputs to spinally projecting PVN neurons. The GABA(B) receptor agonist baclofen (1-50 microM) dose-dependently decreased the frequency but not the amplitude of spontaneous excitatory postsynaptic currents (sEPSCs) and inhibitory postsynaptic currents (sIPSCs). The effect of baclofen on sEPSCs and sIPSCs was completely blocked by 10 microM CGP52432, a selective GABA(B) receptor antagonist. Baclofen also significantly reduced the frequency of both miniature excitatory and miniature inhibitory postsynaptic currents (mEPSCs and mIPSCs). Furthermore, uncoupling pertussis toxin-sensitive G(i/o) proteins with N-ethylmaleimide abolished baclofen-induced inhibition of mEPSCs and mIPSCs. However, the inhibitory effect of baclofen on the frequency of mIPSCs and mEPSCs persisted in the presence of either Cd2+, a voltage-gated Ca2+ channel blocker, or 4-aminopyridine, a blocker of voltage-gated K+ channels. Our results suggest that activation of presynaptic GABA(B) receptors inhibits synaptic GABA and glutamate release to PVN presympathetic neurons. This presynaptic action of GABA(B) receptors is mediated by the N-ethylmaleimide-sensitive G(i/o) proteins, but independent of voltage-gated Ca2+ and K+ channels.

Growth of Agropyron elongatum in a simulated nickel contaminated soil with lime stabilization

A greenhouse study was performed to evaluate the feasibility of using Agropyron elongatum and lime treatment for remediation of a simulated nickel (Ni) contaminated acidic soil. The acid soil was spiked with four levels of Ni, i.e., 0, 15, 50, and 100 mg Ni kg(-1) soil and the soil pH at each Ni level was adjusted to 4, 6 and 8 by liming with CaO. Addition of lime raised the soil pH and resulted in a decrease in concentrations of DTPA-extractable and water-soluble Ni in the soil, with a maximum reduction of 64 and 28 mg kg(-1), respectively at the highest level of Ni treatment as compared to the control without Ni treatment. In general, excessive Ni content in soil, especially at pH 4 inhibited the growth of Agropyron. Liming improved the growth condition and the highest dry weight yield of 12 g pot(-1) was obtained in soil spiked with 15 mg Ni kg(-1) at pH 6; and at the highest level of Ni, the dry weight yield increased from 0.48 to 5.96 g pot(-1) when the pH was increased from 4 to 6. However a further increase in pH to 8 did not improve plant yield because of the unavailability of nutrients at such a high pH. Nickel contents in plant were positively correlated to soil Ni contents at each respective pH level. Most of the Ni taken up by Agropyron was retained in the roots and the highest Ni uptake by plant was 3.9 mg pot(-1) in soil spiked with 100 mg Ni kg(-1) at pH 5.9, which was about 2.6% of total Ni added to the soil. This implies that Agropyron is not a hyperaccumulating species but is highly tolerant. Lime amendment together with the tolerant characteristic of Agropyron could provide a possible means to remediate Ni contaminated soils through phytostabilization.

The wrap-around problem and optimal padding in the exit wave reconstruction using HRTEM images

A free fast Fourier transform software FFTW (www.fftw.org) is used in the exit wave reconstruction and shown to be able to handle images of any size effectively. The wrap-around problem commonly encountered in the exit wave reconstruction is investigated, and a new padding scheme is proposed and its performance is investigated. It is shown that while the usual wrap-around problem may be solved via padding the input high-resolution transmission electron microscopy (HRTEM) images with zero or averaged image intensities, the reconstructed exit wave at its boundary is inevitably distorted by the discontinuity of image intensities at the boundary. The proposed new padding scheme is shown to be able to provide a good estimate of the image intensities immediately outside the boundaries of the HRTEM images, reducing the estimated image intensity discontinuity across the boundaries and therefore providing a larger undistorted view of the exit wave.

MPZL1/PZR, a novel candidate predisposing schizophrenia in Han Chinese

The MPZL1/PZR gene has been mapped to 1q23.3, located in close proximity to a recognized schizophrenia susceptibility locus. Recently, the MPZL1/PZR gene has been found to be significantly upregulated in schizophrenia brain tissue and to play an important role in cell signaling, thus indicating that MPZL1/PZR could be a potential schizophrenia marker. To test this hypothesis, we selected three single nucleotide polymorphisms (SNPs) for genotyping in 523 Han Chinese trios. We found that two individual SNPs were significant at the Bonferroni's corrected significance level P<0.017: rs3767444 (chi2=6.299, P=0.0121) and rs2051656 (chi2=9.856, P=0.0017). Haplotype transmission/disequilibrium tests revealed a significant association with the disease (global P-value=1.064 x 10(-6)), but no specific transmission distortions. Thus, we propose that the MPZL1/PZR gene may be important in the predisposition to schizophrenia among Han Chinese.

Subtype IV of the BK polyomavirus is prevalent in East Asia

BK polyomavirus (BKV) is ubiquitous in human populations, infecting children asymptomatically and then persisting in the kidney. Using either serological or genotyping methods, BKV isolates have been classified into four subtypes (I-IV), with subtype I mainly detected in all countries studied so far. To elucidate the subtype of BKV prevalent in East Asia, we examined BKV-positive urine samples collected from immunocompetent elderly patients in Mongolia, Northeast China, Northwest China, Southeast China, Southwest China, Vietnam and Japan. The 287-bp typing region of the viral genome in each of these samples was PCR-amplified and sequenced, and a phylogenetic tree was constructed. According to the tree, BKV isolates in East Asia were unambiguously classified into subtype I or IV (subtypes II and III were not detected). In Japan, subtype I was mainly detected and subtype IV was rare, whereas in the other regions subtype IV was detected frequently, at rates ranging from 24 to 100%. Thus, East Asia (excluding Japan) is a region in which subtype-IV BKV is prevalent, a finding that requires the view of the geographic distribution of BKV subtypes to be revised. Furthermore, we present evidence that the immunological states of urine donors do not affect the pattern of BKV subtypes.

High-Quality Ultralong Sb2Se3 and Sb2S3 Nanoribbons on a Large Scale via a Simple Chemical Route

Large-scale ultralong single-crystalline Sb2Se3 and Sb2S3 nanoribbons were prepared respectively by reacting SbCl3 with selenium and sulfur powders in glycol solution. Both Sb2Se3 and Sb2S3 nanoribbons are usually hundreds of microns in length, and the structures of the nanoribbons are determined to be of the orthorhombic phases. The Sb2Se3 nanoribbons are typically 100-300 nm in width and 20-60 nm in thickness and grow along the [12] direction. Sb2S3 nanoribbons are wider than Sb2Se3 nanoribbons; Sb2S3 nanoribbons are about 200-500 nm in width and grow along the [001] direction. The growth mechanism of the nanoribbons is investigated based on high-resolution transmission electron microscopy (HRTEM) observations. Optical absorption experiment reveals that Sb2Se3 and Sb2S3 nanoribbons are two semiconductors with bandwidth Eg approximately 1.15 eV and Eg approximately 1.56 eV, respectively.

Application of a generic biosphere model for dose assessments to five European sites

The BIOMOSA (BIOsphere MOdels for Safety Assessment of radioactive waste disposal) project was part of the EC fifth framework research programme. The main goal of this project was to improve the scientific basis for the application of biosphere models in the framework of long-term safety studies of radioactive waste disposal facilities and to enhance the confidence in using biosphere models for performance assessments. The study focused on the development and application of a generic biosphere tool BIOGEM (BIOsphere GEneric Model) using the IAEA BIOMASS reference biosphere methodology, and the comparison between BIOGEM and five site-specific biosphere models. The site-specific models and the generic model were applied to five typical locations in Europe, resulting in estimates of the annual effective individual doses to the critical groups and the ranking of the importance of the exposure pathways for each of the sites. Uncertainty in the results was also estimated by means of stochastic calculations based on variation of the site-specific parameter values. This paper describes the generic model and the deterministic and stochastic results obtained when it was applied to the five sites. Details of the site-specific models and the corresponding results are described in two companion papers. This paper also presents a comparison of the results between the generic model and site-specific models. In general, there was an acceptable agreement of the BIOGEM for both the deterministic and stochastic results with the results from the site-specific models.