In this study, we have used a simple seed-mediated synthesis process to prepare uniform Pd nanorods with average lengths of approximately 200 and 300 nm through the addition of 50-100 microL of 0.004 M copper acetate solution into the growth solution for the first time. Because of their long lengths, they nicely settled to the bottom of the reaction vial and can easily be separated from the suspended faceted particles. The nanorods have an average diameter of approximately 20 nm, so they have high aspect ratios of 10-15 or more. They can readily self-assemble into high-density packing structures on substrates. By increasing the volume of the copper acetate solution added to 250 microL, extensively branched Pd nanocrystals were obtained. The crystal structures of both particle morphologies have been examined. The nanorods possess a penta-twinned structure. Different growth directions have been found for the branched nanocrystals. The growth mechanism of these nanostructures was studied in great detail. A mixture of short Pd rods and faceted particles was formed first and elongated into long rods or branched nanocrystals with the assistance of copper atom deposition. A reduction potential of copper lower than that of palladium leads to periodic deposition and reoxidation of copper atoms on the growing rods and faceted particles. Use of other metal ions did not form long nanorods and branched nanocrystals. UV-vis spectra of the 200 nm Pd nanorods showed a significant absorption band in the near-infrared region with band maximum at approximately 1800 nm, while the 300 nm rods have band maxima of 2000-2100 nm. Both the nanorods and branched nanocrystals were found to serve as highly efficient and recyclable catalysts for catalyzing a Suzuki coupling reaction between phenylboronic acid and iodobenzene. They are also thermally stable under the reflux condition and can be easily removed from the product solution. These novel Pd nanostructures should find use in other palladium-catalyzed reactions.

The performance of clinical tests for disease screening is often evaluated using the area under the receiver‐operating characteristic (ROC) curve (AUC). Recent developments have extended the traditional setting to the AUC with binary time‐varying failure status. Without considering covariates, our first theme is to propose a simple and easily computed nonparametric estimator for the time‐dependent AUC. Moreover, we use generalized linear models with time‐varying coefficients to characterize the time‐dependent AUC as a function of covariate values. The corresponding estimation procedures are proposed to estimate the parameter functions of interest. The derived limiting Gaussian processes and the estimated asymptotic variances enable us to construct the approximated confidence regions for the AUCs. The finite sample properties of our proposed estimators and inference procedures are examined through extensive simulations. An analysis of the AIDS Clinical Trials Group (ACTG) 175 data is further presented to show the applicability of the proposed methods. The Canadian Journal of Statistics 38:8–26; 2010 © 2009 Statistical Society of Canada

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SUMMARYThe objective of this study is to propose a 2.5D ÿnite=inÿnite element procedure for dealing with the ground vibrations induced by moving loads. Besides the two in-plane degrees of freedom (DOFs) per node conventionally used for plane strain elements, an extra DOF is introduced to account for the outof-plane wave transmission. The proÿle of the half-space is divided into a near ÿeld and a semi-inÿnite far ÿeld. The near ÿeld containing loads and irregular structures is simulated by the ÿnite elements, while the far ÿeld covering the soils extending to inÿnity by the inÿnite elements with due account taken of the radiation e ects for moving loads. Enhanced by the automated mesh expansion procedure proposed previously by the writers, the far ÿeld impedances for all the lower frequencies are generated repetitively from the mesh created for the highest frequency considered. Finally, the accuracy of the proposed method is veriÿed through comparison with a number of analytical solutions.

Logistic regression has been widely applied in the field of biomedical research for a long time. In some applications, the covariates of interest have a natural structure, such as that of a matrix, at the time of collection. The rows and columns of the covariate matrix then have certain physical meanings, and they must contain useful information regarding the response. If we simply stack the covariate matrix as a vector and fit a conventional logistic regression model, relevant information can be lost, and the problem of inefficiency will arise. Motivated from these reasons, we propose in this paper the matrix variate logistic (MV-logistic) regression model. The advantages of the MV-logistic regression model include the preservation of the inherent matrix structure of covariates and the parsimony of parameters needed. In the EEG Database Data Set, we successfully extract the structural effects of covariate matrix, and a high classification accuracy is achieved.

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The age and risk level that warrants hepatocellular carcinoma (HCC) screening remains to be defined. To develop risk scores for stratifying average-risk population for mass HCC screening, we conducted a pooled analysis using data from three cohorts involving 12,377 Taiwanese adults 20-80 years of age. During 191,240.3 person-years of follow-up, 387 HCCs occurred. We derived risk scores from Cox's model in two thirds of participants and used another one third for model validation. Besides assessing discrimination and calibration, we performed decision curve analysis to translate findings into public health policy. A risk score according to age, sex, alanine aminotransferase, previous chronic liver disease, family history of HCC, and cumulative smoking had good discriminatory accuracy in both model derivation and validation sets (c-statistics for 3-, 5-, and 10-year risk prediction: 0.76-0.83). It also performed well across cohorts and diverse subgroups. Decision curve analyses revealed that use of the score in selecting persons for screening improved benefit at threshold probabilities of >2% 10-year risk, compared with current guidelines and a strategy of screening all hepatitis B carriers. Using 10-year risk 2% as a threshold for initiating screening, the screening age ranged from 20 to 60 years, depending on the tertile of risk scores and status of hepatitis B/C virus infection. Combining risk-score tertile levels and hepatitis virus status to stratify participants was more sensitive than current guidelines for HCC detection within 10 years (89.4% vs. 76.8%), especially for young-onset HCCs <50 years (79.4% vs. 40.6%), under slightly lower specificity (67.8% vs. 71.8%). Conclusion: A simple HCC prediction algorithm was developed using accessible variables combined with hepatitis virus status, which allows selection of asymptomatic persons for priority of HCC screening. (HEPATOLOGY 2015;61:1934-1944 See Editorial on Page 1783 H epatocellular carcinoma (HCC) is a leading cause of cancer-related deaths worldwide. Chronic infection with hepatitis B virus (HBV) accounts for 50%-80% of global HCC cases, whereas 10%-25% of cases are attributable to hepatitis C virus (HCV). 1 There is evidence showing that community-wide ultrasonography (USG)-based mass screening for HCC reduces mortality, 2,3 but less than 20% of patients with diagnosed HCC reported receiving prediagnosis regular screening. 4 Current expert guidelines recommend performing HCC screening in all patients with cirrhosis and for chronic HBV carriers, including Asian men 40 years

This study investigates the crystalline quality, surface, and optical properties of semi-polar GaN (11 2 2) grown on m-sapphire substrates with and without a CrN interlayer using molecular beam epitaxy (MBE). The results of the characterization performed by an X-ray diffraction system, scanning electron microscopy and photoluminescence system, all indicate that the crystalline quality, threading dislocation, surface morphology and optical properties of (11 22) GaN grown with the CrN were superior to those when CrN was not inserted. Details of defect-related emissions of these two samples were observed and investigated in temperature dependent PL measurements, with a low temperature PL spectrum. A weak basal stacking fault related (BSF-related) emission at 3.432 eV was observed in these two samples. In comparison, the BSF-related emission peak as a shoulder to the near band edge (NBE) peaks for the semi-polar GaN grown without CrN was hardly distinguishable at a low temperature.