Carbon Nanotubes as Nanoelectromechanical Systems

We theoretically study the interplay between electrical and mechanical properties of suspended, doubly clamped carbon nanotubes in which charging effects dominate. In this geometry, the capacitance between the nanotube and the gate(s) depends on the distance between them. This dependence modifies the usual Coulomb models and we show that it needs to be incorporated to capture the physics of the problem correctly. We find that the tube position changes in discrete steps every time an electron tunnels onto it. Edges of Coulomb diamonds acquire a (small) curvature. We also show that bistability in the tube position occurs and that tunneling of an electron onto the tube drastically modifies the quantized eigenmodes of the tube. Experimental verification of these predictions is possible in suspended tubes of sub-micron length.Comment: 8 pages, 5 eps figures included. Major changes; new material adde

Multi-ancestry genome-wide study identifies effector genes and druggable pathways for coronary artery calcification

Coronary artery calcification (CAC), a measure of subclinical atherosclerosis, predicts future symptomatic coronary artery disease (CAD). Identifying genetic risk factors for CAC may point to new therapeutic avenues for prevention. Currently, there are only four known risk loci for CAC identified from genome-wide association studies (GWAS) in the general population. Here we conducted the largest multi-ancestry GWAS meta-analysis of CAC to date, which comprised 26,909 individuals of European ancestry and 8,867 individuals of African ancestry. We identified 11 independent risk loci, of which eight were new for CAC and five had not been reported for CAD. These new CAC loci are related to bone mineralization, phosphate catabolism and hormone metabolic pathways. Several new loci harbor candidate causal genes supported by multiple lines of functional evidence and are regulators of smooth muscle cell-mediated calcification ex vivo and in vitro. Together, these findings help refine the genetic architecture of CAC and extend our understanding of the biological and potential druggable pathways underlying CAC. Radiolog

Factors Associated with Revision Surgery after Internal Fixation of Hip Fractures

Background: Femoral neck fractures are associated with high rates of revision surgery after management with internal fixation. Using data from the Fixation using Alternative Implants for the Treatment of Hip fractures (FAITH) trial evaluating methods of internal fixation in patients with femoral neck fractures, we investigated associations between baseline and surgical factors and the need for revision surgery to promote healing, relieve pain, treat infection or improve function over 24 months postsurgery. Additionally, we investigated factors associated with (1) hardware removal and (2) implant exchange from cancellous screws (CS) or sliding hip screw (SHS) to total hip arthroplasty, hemiarthroplasty, or another internal fixation device. Methods: We identified 15 potential factors a priori that may be associated with revision surgery, 7 with hardware removal, and 14 with implant exchange. We used multivariable Cox proportional hazards analyses in our investigation. Results: Factors associated with increased risk of revision surgery included: female sex, [hazard ratio (HR) 1.79, 95% confidence interval (CI) 1.25-2.50; P = 0.001], higher body mass index (fo

Macroscopic Portal Vein Thrombosis in HCC Patients

PubMedID: 30009156Macroscopic portal vein invasion (PVT) by hepatocellular carcinoma (HCC) in the liver is one of the most important negative prognostic factors for HCC patients. The characteristics of a large cohort of such patients were examined. We found that the percent of patients with PVT significantly increased with increasing maximum tumor diameter (MTD), from 13.7% with tumors of MTD 10cm. There were similar numbers of HCC patients with very large tumors with and without PVT. Thus, MTD alone was insufficient to explain the presence of PVT, as were high AFP levels, since less than 50% of high AFP patients had PVT. However, the percent of patients with PVT was also found to significantly increase with increasing blood alpha-fetoprotein (AFP) levels and tumor multifocality. A logistic regression model that included these 3 factors together showed an odds ratio of 17.9 for the combination of MTD>5.0cm plus tumor multifocality plus elevated AFP, compared to low levels of these 3 parameters. The presence or absence of macroscopic PVT may therefore represent different HCC aggressiveness phenotypes, as judged by a significant increase in tumor multifocality and AFP levels in the PVT positive patients. Factors in addition to MTD and AFP must also contribute to PVT development. © 2018 Hikmet Akkiz et al

C-Reactive protein and platelet-lymphocyte ratio as potential tumor markers in low-alpha-fetoprotein hepatocellular carcinoma

PubMedID: 30336489The hepatocellular carcinoma (HCC) tumor marker alpha-fetoprotein (AFP) is only elevated in about half of the HCC patients, limiting its usefulness in following the effects of therapy or screening. New markers are needed. It has been previously noted that the inflammation markers C-reactive protein (CRP) and platelet-lymphocyte ratio (PLR) are prognostically important and may reflect HCC aggressiveness. We therefore examined these 2 markers in a low-AFP HCC cohort and found that for HCCs > 2 cm, both markers significantly rise with an increasing maximum tumor diameter (MTD). We calculated the sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and Youden index value for each marker, and their area-under-the-curve values for each MTD group. Patients were dichotomized into 2 groups based on the CRP and PLR from the receiver-operating characteristic curve analysis. In the logistic regression models of the 4 different MTD patient groups, CRP and PLR levels were statistically significant to estimate MTD in univariate logistic regression models of MTD groups > 2 cm. CRP and PLR were then combined, and the combination was statistically significant to estimate MTD groups of 3-, 4-, and 5-cm cutoffs. CRP and PLR thus have potential as tumor markers for low-AFP HCC patients, and possibly for screening. © 2018S. Karger AG, Basel.National Institutes of Health: CA 82723This work was supported in part by the NIH grant CA 82723 (B.I.C)