The cumulative effects of known susceptibility variants to predict primary biliary cirrhosis risk.

Multiple genetic variants influence the risk for development of primary biliary cirrhosis (PBC). To explore the cumulative effects of known susceptibility loci on risk, we utilized a weighted genetic risk score (wGRS) to evaluate whether genetic information can predict susceptibility. The wGRS was created using 26 known susceptibility loci and investigated in 1840 UK PBC and 5164 controls. Our data indicate that the wGRS was significantly different between PBC and controls (P=1.61E-142). Moreover, we assessed predictive performance of wGRS on disease status by calculating the area under the receiver operator characteristic curve. The area under curve for the purely genetic model was 0.72 and for gender plus genetic model was 0.82, with confidence limits substantially above random predictions. The risk of PBC using logistic regression was estimated after dividing individuals into quartiles. Individuals in the highest disclosed risk group demonstrated a substantially increased risk for PBC compared with the lowest risk group (odds ratio: 9.3, P=1.91E-084). Finally, we validated our findings in an analysis of an Italian PBC cohort. Our data suggested that the wGRS, utilizing genetic variants, was significantly associated with increased risk for PBC with consistent discriminant ability. Our study is a first step toward risk prediction for PBC

Axisymmetric slosh frequencies of a liquid mass in a circular cylinder

Spectral eigenvalue methods along with some lower-dimensional techniques are used to determine the natural frequencies of a liquid slug in a circular tube. The contact lines are either pinned or governed by a slip coefficient assumed small. Corresponding physical experiments are conducted for a borosilicate glass tube and a treated water slug. Gravitational and viscous effects are neglected for the analyses. The spectral results agree well with a simple spherical end cap approximation (zero dimensional) for large aspect ratio slugs and with a membrane approximation (one dimensional) for small aspect ratios. The experimental observations for different aspect ratios agree well with the predictions, although the gravity, viscosity and/or slip are neglected in the analyses. © 2003 American Institute of Physics.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/71120/2/PHFLE6-15-12-3659-1.pd

Worst-case complexity of smoothing quadratic regularization methods for non-lipschitzian optimization

2013-2014 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishe

Quasiclassical trajectory study of the SiH4+H→SiH3+H2 reaction on a global ab initio potential energy surface

The SiH4+H→SiH3+H2 reaction has been investigated by the quasiclassical trajectory (QCT) method on a recent global ab initio potential energy surface [ M. Wang et al., J. Chem. Phys. 124, 234311 (2006) ]. The integral cross section as a function of collision energy and thermal rate coefficient for the temperature range of 300–1600 K have been obtained. At the collision energy of 9.41 kcal/mol, product energy distributions and rovibrational populations are explored in detail, and H2 rotational state distributions show a clear evidence of two reaction mechanisms. One is the conventional rebound mechanism and the other is the stripping mechanism similar to what has recently been found in the reaction of CD4+H [ J. P. Camden et al., J. Am. Chem. Soc. 127, 11898 (2005) ]. The computed rate coefficients with the zero-point energy correction are in good agreement with the available experimental data

Dexmo: An inexpensive and lightweight mechanical exoskeleton for motion capture and force feedback in VR

We present Dexmo: an inexpensive and lightweight mechanical exoskeleton system for motion capturing and force feedback in virtual reality applications. Dexmo combines multiple types of sensors, actuation units and link rod structures to provide users with a pleasant virtual reality experience. The device tracks the user’s motion and uniquely provides passive force feedback. In combination with a 3D graphics rendered environment, Dexmo provides the user with a realistic sensation of interaction when a user is for example grasping an object. An initial evaluation with 20 participants demonstrate that the device is working reliably and that the addition of force feedback resulted in a significant reduction in error rate. Informal comments by the participants were overwhelmingly positive.This is the accepted manuscript. The final version is available at http://dl.acm.org/citation.cfm?doid=2858036.2858487

A study of aerosol liquid water content based on hygroscopicity measurements at high relative humidity in the North China Plain

Water can be a major component of aerosol particles, also serving as a medium for aqueous-phase reactions. In this study, a novel method is presented to calculate the aerosol liquid water content at high relative humidity based on measurements of aerosol hygroscopic growth factor, particle number size distribution and relative humidity in the Haze in China (HaChi) summer field campaign (July–August 2009) in the North China Plain. The aerosol liquid water content calculated using this method agreed well with that calculated using a thermodynamic equilibrium model (ISORROPIA II) at high relative humidity (>60%) with a correlation coefficient of 0.96. At low relative humidity (<60%), an underestimation was found in the calculated aerosol liquid water content by the thermodynamic equilibrium model. This discrepancy mainly resulted from the ISORROPIA II model, which only considered limited aerosol chemical compositions. The mean and maximum values of aerosol liquid water content during the HaChi campaign reached 1.69 × 10&minus;4 g m−3 and 9.71 × 10&minus;4 g m−3, respectively. A distinct diurnal variation of the aerosol liquid water content was found, with lower values during daytime and higher ones at night. The aerosol liquid water content depended strongly on the relative humidity. The aerosol liquid water content in the accumulation mode dominated the total aerosol liquid water content

Low frequency split cycle cryocooler

A split cycle Stirling cryocooler with two different drive motors and operating at a low drive frequency can have high thermodynamic efficiency. The temperature of the cold end of the cryocooler varies with drive frequency, voltage of the input electrical power and initial charge pressure values. The cryocooler operating at 8 Hz can provide 7 watts of refrigeration at 77 K for 230 watts of electrical input power

Termination of Cryogenian ironstone deposition by deep ocean euxinia

Widespread deposition of iron-rich sedimentary rocks (ironstones) occurred during the Sturtian ice age, the earlier of two Cryogenian ‘Snowball Earth’ glaciations. However, the reasons for the termination of Cryogenian Iron Formation (CIF) deposition remain poorly understood. Here we report a multi-isotope (Fe-C-S) study of the Xinyu CIF in South China that can directly address this question. The isotopic compositions of these multivalent elements exhibit remarkable covariance at the top of the Xinyu CIF that reflects progressive redox stratification during iron oxide deposition. Iron oxide deposition ended abruptly due to the titration of ferrous iron as pyrite following a large influx of riverine sulfate. Although termination of CIF deposition is commonly attributed to oxygenation, our data show that at least in some Cryogenian ocean basins, CIF deposition ended with the spread of euxinic rather than oxygenated waters

Scalable synthesis of wrinkled mesoporous titania microspheres with uniform large micron sizes for efficient removal of Cr(VI)

Aerosol-assisted methods possess a strong capability for synthesis of titania (TiO2) microspheres. For dynamic separation applications, rough TiO2 microspheres with uniform large micron sizes, high external-surface-area-to-volume ratios, high surface areas, uniform mesopores and abundant hydroxyl groups are desirable. Herein, we demonstrate the combination of evaporation induced self-assembly (EISA) with a microfluidic-jet spray drying process for scalable synthesis of novel mesoporous TiO2 materials with the above-mentioned properties for Cr(vi) removal under both static and dynamic conditions. The TiO2 materials are spherical with uniform large micron sizes (∼45 μm). They possess wrinkled surfaces and thus have high particle external-surface-area-to-volume ratios. They show high surface areas (22-138 m2 g-1), large pore volumes (0.15-0.27 cm3 g-1) and uniform mesopores (5.2-20.7 nm). They carry abundant surface Ti-OH groups due to the presence of oxygen vacancies and the Ti3+ valence state. Several experimental parameters, such as drying and calcination temperatures, are varied, leading to TiO2 samples with tunable surface areas and mesopore sizes. They can be adopted as batch sorbents for removal of Cr(vi) in water with fast adsorption rates, large capacities and pH-dependent adsorption behavior. Part of the adsorbed Cr(vi) can be reduced to Cr(iii) in acidic solutions. The influences of adsorbent properties on adsorption performance are elucidated. Moreover, their uniform large micron sizes make them excellent fillers for efficient separation of Cr(vi) in dynamic flows with similar performance to that under static conditions, as well as easy regeneration and high cycling stability. Their adsorption performance under flowing conditions is much better than those of commercial TiO2 nanoparticles and mesoporous TiO2 materials prepared by a conventional EISA method, which make them very attractive for practical dynamic separation applications