Edge mode based graphene nanomechanical resonators for high-sensitivity mass sensor

We perform both molecular dynamics simulations and theoretical analysis to study the sensitivity of the graphene nanomechanical resonator based mass sensors, which are actuated following the global extended mode or the localized edge mode. We find that the mass detection sensitivity corresponding to the edge mode is about three times higher than that corresponding to the extended mode. Our analytic derivations reveal that the enhancement of the sensitivity originates in the reduction of the effective mass for the edge mode due to its localizing feature

Association of p53 Codon 72 Polymorphism with Risk of Hypopharyngeal Squamous Cell Carcinoma in Taiwan

Backgroundp53 polymorphism at codon 72 is a known risk marker for various malignancies, but it has not been studied in hypopharyngeal cancer. This study investigated the genotype distribution of p53 codon 72 polymorphism in hypopharyngeal cancer patients and non-cancer controls matched for age, gender, alcohol consumption and smoking habit.MethodsGenomic DNA was extracted from peripheral blood cells of 53 patients with hypopharyngeal cancer and 53 non-cancer controls. Codon 72 polymorphism of p53 was identified by polymerase chain reaction-restriction fragment length polymorphism.ResultsPatients with hypopharyngeal cancer had higher frequencies of Pro/Pro (26.4% vs. 13.2%) and Pro/Arg (51.0% vs. 45.3%) but lower frequencies of Arg/Arg (22.6% vs. 45.1%) compared to controls. Compared to Arg/Arg genotypes, Pro/Pro genotypes had a relative risk of hypopharyngeal cancer of 3.667 (95% confidence interval, 1.16-11.56; p = 0.03). As a group, patients with Pro/Pro or Arg/Pro who were carriers of the Pro allele had a higher relative risk of hypopharyngeal cancer compared to Arg homozygous carriers (odds ratio, 2.415; 95% confidence interval, 1.04-5.64; p = 0.04).ConclusionThis study demonstrated that p53 codon 72 Pro homozygosity is associated with a higher risk of developing hypopharyngeal cancer

FgPrp4 Kinase Is Important for Spliceosome B-Complex Activation and Splicing Efficiency in Fusarium graminearum

PRP4 encodes the only kinase among the spliceosome components. Although it is an essential gene in the fission yeast and other eukaryotic organisms, the Fgprp4 mutant was viable in the wheat scab fungus Fusarium graminearum. Deletion of FgPRP4 did not block intron splicing but affected intron splicing efficiency in over 60% of the F. graminearum genes. The Fgprp4 mutant had severe growth defects and produced spontaneous suppressors that were recovered in growth rate. Suppressor mutations were identified in the PRP6, PRP31, BRR2, and PRP8 orthologs in nine suppressor strains by sequencing analysis with candidate tri-snRNP component genes. The Q86K mutation in FgMSL1 was identified by whole genome sequencing in suppressor mutant S3. Whereas two of the suppressor mutations in FgBrr2 and FgPrp8 were similar to those characterized in their orthologs in yeasts, suppressor mutations in Prp6 and Prp31 orthologs or FgMSL1 have not been reported. Interestingly, four and two suppressor mutations identified in FgPrp6 and FgPrp31, respectively, all are near the conserved Prp4-phosphorylation sites, suggesting that these mutations may have similar effects with phosphorylation by Prp4 kinase. In FgPrp31, the non-sense mutation at R464 resulted in the truncation of the C-terminal 130 aa region that contains all the conserved Prp4-phosphorylation sites. Deletion analysis showed that the N-terminal 310-aa rich in SR residues plays a critical role in the localization and functions of FgPrp4. We also conducted phosphoproteomics analysis with FgPrp4 and identified S289 as the phosphorylation site that is essential for its functions. These results indicated that FgPrp4 is critical for splicing efficiency but not essential for intron splicing, and FgPrp4 may regulate pre-mRNA splicing by phosphorylation of other components of the tri-snRNP although itself may be activated by phosphorylation at S289

Nanofibrous Spongy Microspheres for the Delivery of Hypoxia-primed Human Dental Pulp Stem Cells to Regenerate Vascularized Dental Pulp

Dental pulp infection and necrosis are widespread diseases. Conventional endodontic treatments result in a devitalized and weakened tooth. In this work, we synthesized novel star-shaped polymer to self-assemble into unique nanofibrous spongy microspheres (NF-SMS), which were used to carry human dental pulp stem cells (hDPSCs) into the pulp cavity to regenerate living dental pulp tissues. It was found that NF-SMS significantly enhanced hDPSCs attachment, proliferation, odontogenic differentiation and angiogenesis, as compared to control cell carriers. Additionally, NF-SMS promoted vascular endothelial growth factor (VEGF) expression of hDPSCs in a 3D hypoxic culture. Hypoxia-primed hDPSCs/NF-SMS complexes were injected into the cleaned pulp cavities of rabbit molars for subcutaneous implantation in mice. After 4 weeks, the hypoxia group significantly enhanced angiogenesis inside the pulp chamber and promoted the formation of ondontoblast-like cells lining along the dentin-pulp interface, as compared to the control groups (hDPSCs alone group, NF-SMS alone group, and hDPSCs/NF-SMS group pre-cultured under normoxic conditions). Furthermore, in an in situ dental pulp repair model in rats, hypoxia-primed hDPSCs/NF-SMS were injected to fully fill the pulp cavity and regenerate pulp-like tissues with a rich vasculature and a histological structure similar to the native pulp