Study of the Tribological Properties of Modified Potassium Titanate Whisker-Reinforced Resin-Based Friction Composites

The surface modifications of reinforcing components have significant influence on the tribological performance of resin-based friction composites. In this work, 3-aminopropyltriethoxysilane coupling agent (KH550) and octadecyltrichlorosilane (OTS) were used to modify nanosized potassium titanate whiskers (PTW). Subsequently, the modified potassium titanate whiskers were used as reinforcing components in phenolic resin-based friction composites. The tribological behavior and wear mechanism of the composites were studied. The results show that the surface free energy of 5% OTS-modified potassium titanate whiskers is the closest to that of the resin matrix, which is 26.4 mJ/m2. Moreover, the OTS-modified PTW-reinforced composites possess a more stable friction coefficient and a lower wear rate at high temperature. The OTS-modified PTW-reinforced composite (O-C) has a 19% lower total wear rate than the unmodified PTW-reinforced composite (P-C). That is mainly because the modified potassium titanate whisker is more evenly distributed in the resin matrix and tightly bonded to the resin. Results demonstrate that OTS-modified PTW-reinforced composites displayed preferable tribological performance. This article provides a new method for PTW modifications in improving the tribological performance of the resin-based friction composites.</p

Fine Mapping of a Region of Chromosome 11q23.3 Reveals Independent Locus Associated with Risk of Glioma

<div><h3>Background</h3><p>A single nucleotide polymorphism (SNP) at locus 11q23.3 (rs498872) in the near 5′-UTR of the <em>PHLDB1</em> gene was recently implicated as a risk factor for gliomas in a genome-wide association study, and this involvement was confirmed in three additional studies.</p> <h3>Methodology/Principal Findings</h3><p>To identify possible causal variants in the region, the authors genotyped 15 tagging SNPs in the 200 kb genomic region at 11q23.3 locus in a Chinese Han population-based case-control study with 983 cases and 1024 controls. We found evidence for an association between two independent loci (both the <em>PHLDB1</em> and the <em>ACRN1</em> genes) and a predisposition for gliomas. Among the multiple significant SNPs in the <em>PHLDB1</em> gene region, the rs17749 SNP was the most significant [<em>P</em> = 1.31×10⁻⁶ in a recessive genetic model]. Additionally, two novel SNPs (rs2236661 and rs494560) that were independent of rs17749 were significantly associated with glioma risk in a recessive genetic model [<em>P</em> = 1.31×10⁻⁵ and <em>P</em> = 3.32×10⁻⁵, respectively]. The second novel locus was within the <em>ARCN1</em> gene, and it was associated with a significantly reduced risk for glioma.</p> <h3>Conclusions/Significance</h3><p>Our data strongly support <em>PHLDB1</em> as a susceptibility gene for glioma, also shedding light on a new potentially candidate gene, <em>ARCN1</em>.</p> </div

Characteristics of the cases and controls in a Chinese study population.

<p>Bold characters indicate corresponding <i>P</i> values are less than 0.05.</p>a<p>Other gliomas including oligodendrogliomas, ependymomas, ormixed gliomas.</p

A schematic view of genetic association between SNPs at 11q23.3 and glioma risk in Chinese Han populations.

<p>A schematic view of genetic association between SNPs at 11q23.3 and glioma risk in Chinese Han populations.</p

Association between the cumulative effect of four significant SNPs^a and the risk of glioma in a Chinese population.

<p>Bold characters indicate corresponding <i>P</i> values are less than 6.67×10⁻⁴.</p>a<p>Significant SNPs including s7115634, rs2236661, rs494560 and rs17748.</p>b<p>Adjusted for age and gender.</p

Genotype frequencies of five glioma susceptibility SNPs among cases and controls and their association with glioma risk in a Chinese population.

<p>Bold characters indicate corresponding <i>P</i> values are less than 6.67×10⁻⁴.</p>a<p>Adjusted for age and gender.</p>b<p>Other types including astrocytic glioma, oligodendrogliomas, ependymomas, ormixed gliomas.</p

LD plot of 11q23.3 using 15SNPs in 1024 ethnic Han Chinese controls.

<p>This plot was generated by the Haploview program with four Gamete Rule setting. Four blocks were determined. The rs number (top; from left to right) corresponds to the SNP name and the level of pairwise D’ indicates the degree of LD between the two SNPs.</p

Association of 15 selected SNPs in 11q23.3 region with the risk of glioma in a Chinese population.

<p>Bold characters indicate corresponding <i>P</i> values are less than 6.67×10⁻⁴.</p>a<p>Odds ratios for the carriers of the minor allele and their associated 95% confidence intervals.</p>b<p>Adjusted for age and gender.</p