Separation, characterization and leaching behaviors of heavy metals in contaminated river sediments

In this research, the sequential extraction test was conducted to understand the characteristic of heavy metals in the sediment. Subsequently, the pH-dependent leaching test, percolation test were subjected to explore the possible leaching of heavy metals and stabilizing mechanism. Finally, based on the resuts of pH dependent test,the acid/chemical washing were applied to predict long-term, leaching characteristics. The results from the sediment characteristic analyses showed that the concentrations of heavy metals (such as Cu, Pb, Zn, Ni, and Cr) in river sediments exceeded the upper limit of Sediment Quality Standard of Taiwan, implying further decontamination works should be addressed. Results from the chemical washing (extraction) showed that the heavy metal removal efficiency was good when washed with 2N HCl for 120 minutes; the order of removal efficiency was Ni 90% > Zn 87% > Pb 85% > Cu 83% > Cr 70%. For chelation extraction, the suitable operating condition was achieved with 0.5M Citric Acid after 120 minutes contact; the order of heavy metal ion capturing efficiency was Zn 61% > Ni 54% > Pb 40% > Cu 36% > Cr 24%. Comparing the heavy metal bonding types before and after chemical washing (extraction) showed that some metal ions exist in residual forms in the sediments (Ni, Zn, Cu); however, after the washing process, the heavy metal ions became more exchangeable forms with higher bioavailability. Keywords: sediment, heavy metal, leaching test, chemical washing

Social stream classification with emerging new labels

Singapore National Research Foundation under International Research Centres in Singapore Funding Initiativ

Down-regulated CK8 expression in human intervertebral disc degeneration

As an intermediate filament protein, cytokeratin 8 (CK8) exerts multiple cellular functions. Moreover, it has been identified as a marker of notochord cells, which play essential roles in human nucleus pulposus (NP). However, the distribution of CK8 positive cells in human NP and their relationship with intervertebral disc degeneration (IDD) have not been clarified until now. Here, we found the percentage of CK8 positive cells in IDD (25.7+/-4.14%) was significantly lower than that in normal and scoliosis NP (51.9+/-9.73% and 47.8+/-5.51%, respectively, p<0.05). Western blotting and qRT-PCR results confirmed the down-regulation of CK8 expression in IDD on both of protein and mRNA levels. Furthermore, approximately 37.4% of cell clusters were CK8 positive in IDD. Taken together, this is the first study to show a down-regulated CK8 expression and the percentage of CK8 positive cell clusters in IDD based upon multiple lines of evidence. Consequently, CK8 positive cells might be considered as a potential option in the development of cellular treatment strategies for NP repair.published_or_final_versio

Nonlinear relativistic optics in the single cycle, single wavelength regime and kilohertz repetition rate

Pulses of few optical cycles, focused on one wavelength with relativistic intensities can be produced at a kilohertz repetition rate. By properly choosing the plasma and laser parameters, relativistic nonlinear effects, such as channeling and electron and ion acceleration to tens of megaelectronvolts are demonstrated. © 2002 American Institute of Physics.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/87926/2/138_1.pd

The shear mode of multilayer graphene

The quest for materials capable of realizing the next generation of electronic and photonic devices continues to fuel research on the electronic, optical and vibrational properties of graphene. Few-layer graphene (FLG) flakes with less than ten layers each show a distinctive band structure. Thus, there is an increasing interest in the physics and applications of FLGs. Raman spectroscopy is one of the most useful and versatile tools to probe graphene samples. Here, we uncover the interlayer shear mode of FLGs, ranging from bilayer graphene (BLG) to bulk graphite, and suggest that the corresponding Raman peak measures the interlayer coupling. This peak scales from ~43 cm−1 in bulk graphite to ~31 cm−1 in BLG. Its low energy makes it sensitive to near-Dirac point quasiparticles. Similar shear modes are expected in all layered materials, providing a direct probe of interlayer interactions

The effect of chain length and side chains on the solubility of peptides in water from 278.15 K to 313.15 K: a case study in glycine homopeptides and dipeptides

The thermodynamic properties of peptides are significant in terms of the crystallization conditions of biomaterials. In this work, we seek to understand and explain the effect of side chains and chain length on the solubility of peptides. The amino acid residues of dipeptides investigated here were chosen based on their difference in side chain properties. The modified Apelblat equation was used to correlate the relationship between the solubility in water and temperature. In order to explore solute–solvent interactions, the solvation free energies of these peptides were calculated by Molecular Dynamic simulations. This work gives an indication of the effects of side chains and chain length on the solubility of amino acids and peptides in water under different temperatures, which not only provides the thermodynamic data for peptides, but is also critical in the prediction of peptide solubility using Statistical Associating Fluid Theory (SAFT)

The numerical simulation of continuous Nd : YAG laser-annealing of InP

The semiconductor solid phase epitaxial model of continuous laser-annealing is used to simulate the laser-annealing process of different doping concentration of InP at the continuous Nd:YAG laser. Specially, quasi-static model is used to simulate the radial heat dissipation from radiant region to radiationless region. At the same time, thermal conductivity and optical absorption coefficient varied with temperature is also considered. The method of hidden-form different is used in solving one-dimensional, non-homogeneous, nonlinear partial differential equation of heat conduction. At the room temperature T-0=300K and the power intensity of laser I-0=800W/cm(2), the result is that the temperature of surface reaches about 1290K after 3.8sec

GWAS for discovery and replication of genetic loci associated with sudden cardiac arrest in patients with coronary artery disease

<p>Abstract</p> <p>Background</p> <p>Epidemiologic evidence suggests a heritable component to risk for sudden cardiac arrest independent of risk for myocardial infarction. Recent candidate gene association studies for community sudden cardiac arrests have focused on a limited number of biological pathways and yielded conflicting results. We sought to identify novel gene associations for sudden cardiac arrest in patients with coronary artery disease by performing a genome-wide association study.</p> <p>Methods</p> <p>Tagging SNPs (n = 338,328) spanning the genome were typed in a case-control study comparing 89 patients with coronary artery disease and sudden cardiac arrest due to ventricular tachycardia or ventricular fibrillation to 520 healthy controls.</p> <p>Results</p> <p>Fourteen SNPs including 7 SNPs among 7 genes (ACYP2, AP1G2, ESR1, DGES2, GRIA1, KCTD1, ZNF385B) were associated with sudden cardiac arrest (all p < 1.30 × 10^-7), following Bonferroni correction and adjustment for population substructure, age, and sex; genetic variation in ESR1 (p = 2.62 × 10^-8; Odds Ratio [OR] = 1.43, 95% confidence interval [CI]:1.277, 1.596) has previously been established as a risk factor for cardiovascular disease. In tandem, the role of 9 genes for monogenic long QT syndrome (LQT1-9) was assessed, yielding evidence of association with CACNA1C (LQT8; p = 3.09 × 10^-4; OR = 1.18, 95% CI:1.079, 1.290). We also assessed 4 recently published gene associations for sudden cardiac arrest, validating NOS1AP (p = 4.50 × 10^-2, OR = 1.15, 95% CI:1.003, 1.326), CSMD2 (p = 6.6 × 10^-3, OR = 2.27, 95% CI:1.681, 2.859), and AGTR1 (p = 3.00 × 10^-3, OR = 1.13, 95% CI:1.042, 1.215).</p> <p>Conclusion</p> <p>We demonstrate 11 gene associations for sudden cardiac arrest due to ventricular tachycardia/ventricular fibrillation in patients with coronary artery disease. Validation studies in independent cohorts and functional studies are required to confirm these associations.</p