Boundary node correction and superconvergence in the FEM

Convergence improvement and superconvergence behaviour, obtained by the simple boundary node correction (BNC) procedure for certain stress-like variables of smoothed FEM solutions, are reported in this paper. The effectiveness of BNC is shown through three examples of steady flow problems, and a posterior error analysis based on the multiple-mesh extrapolation technique has been used for estimating the convergence rates.     

Effects of Siqi Decoction on Concentration of Nitric Oxide and Activity of Nitric Oxide Synthase in Blood Serum of Rats with Myocardial Ischemia

To study the effects of Siqi decoction on rats with Myocardial Ischemia, the model of Myocardium Ischemia was made for the Wistar rats cured with posterior pituitary injection through vein in tail. Siqi decoction, Diaoxinxuekang（DK） and Fufangdanshenpian（FD）, the latter two drugs of which were effective TCM drugs of anti-Myocardial Ischemia at present, were administrated to the rats with Myocardium Ischemia for 5 days to compare the effect of anti-Myocardium Ischemia as reference drugs by measuring the changes of NO concentration and activity of NOS in the rat blood serum with Myocardial Ischemia. There was a remarkable increase in the NO concentration and activity of NOS in serum in Siqi decoction groups compared with those in control group（p〈0.05）. The results of the prevention group in experiment of Siqi decoction are better than those of the cure group. Siqi decoction was really fit for Myocardium Ischemia via increasing NO concentration by stimulating the activity of NOS in serum. The effect of Siqi decoction against Myocardium Ischemia in preventive group is better than the curative that of Siqi decoction in the curative group.     

Bionic antibacterial modification of IOL through SI-RAFT polymerization of P(TOEAC-co-MPC) brushes to prevent PCO and endophthalmitis

Various complications such as posterior capsule opacification (PCO) and endophthalmitis occur after intraocular lenses (IOLs) implantation in cataract surgery. It is urgent to construct antifouling and antibacterial IOLs to lower the incidence of PCO and endophthalmitis. Bionic zwitterionic polymer such as 2-methacryloyloxyethyl phosphorylcholine (MPC) shows excellent performance in resisting nonspecific proteins and bacterial adhesion. In this work, a novel bionic brushes coating containing MPC and N, N, N-trimethyl-2-((4-(2-(4-nonylphenoxy) ethoxy)-4-oxobut-2-enoyl) oxy) ethan-1-aminium chloride (TOEAC), a quaternary ammonium monomer, was prepared onto IOLs using reversible addition–fragmentation chain transfer (RAFT) polymerization method. The P(TOEAC-co-MPC) brushes exhibited excellent antifouling efficiency against bovine serum albumin, Staphylococcus aureus, and human lens epithelial cells. In addition, the P(TOEAC-co-MPC) brushes showed excellent antibacterial and antibiofilm abilities and good biocompatibility. An in vivo study confirmed that the P(TOEAC-co-MPC) brushes effectively prevented PCO and endophthalmitis. Consequently, the P(TOEAC-co-MPC) bionic brushes are promising for IOLs surface modification to resist postoperative complications for long-term implantation.     

Influence of glottal closure configuration on vocal efficacy in young normal-speaking women

Posterior closure insufficiency of the glottis is often mentioned in connection with permanent voice disorders. Recently published studies have revealed that an incomplete closure of the glottis can be found also in normal-speaking voices, especially in women. However, the effect of glottal closure configuration on vocal efficacy is not sufficiently clarified. The purpose of this study was to determine the effect of glottal closure configuration on singing and speaking voice characteristics. Overall, 520 young female normal-speaking subjects were examined by videostroboscopy for different phonation conditions in the combination of soft, loud, low, and/or high phonation and by voice range profile measurements. According to the videostroboscopic analysis, the subjects were subdivided into four groups: complete closure of the vocal folds already in soft phonation (group 1), closure of the vocal fold with increasing intensity (group 2), persistent closure insufficiencies despite increasing intensity (group 3), and hourglass-shaped closure in subjects with vocal nodules (group 4). Subjects in which the glottal closure could not be evaluated sufficiently were subclassified into group 5 (missing values).

Selected criteria of the singing and speaking voice were evaluated and statistically processed according to the mentioned subclassification. Group 1 reached significantly the highest sound pressure levels (SPL_max) for the singing voice as well as for the shouting voice. Group 3 showed a limited capacity to increase the intensity of the singing and speaking voice. The results gathered in this study objectify the relationship of insufficient glottal closure and reduced vocal capabilities. As long as no conclusive data on long-term consequences of insufficient glottal closure are available, a prophylactic improvement of the laryngeal situation especially in female professional voice users by voice therapy should be recommended.     

Estimation of the Failure Rate in a Partially Accelerated Life Test: A Sequential Approach

Abstract

Consider the situation in which a group of units are put on a partially accelerated life test. It is assumed that the lifelengths of the units are independent and exponentially distributed random variables with common failure rate θ, and that θ is the value of a random variable having a gamma distribution. A two‐stage sequential procedure for estimating θ under the squared error loss is proposed. In the first stage, the units are put on the test under normal stress up to time t, where t is determined as a stopping time that minimizes the expected loss plus cost of running the test. In the second stage, the stress is raised to a higher level for those units that did not fail by time t and held constant until they all fail. The accumulated data are then used to estimate θ with the Bayes estimator.     

On Nearest Neighbor Classification Using Adaptive Choice of k

Nearest neighbor classification is one of the simplest and popular methods for statistical pattern recognition. It classifies an observation x to the class, which is the most frequent in the neighborhood of x. The size of this neighborhood is usually determined by a predefined parameter k. Normally, one uses cross-validation techniques to estimate the optimum value of this parameter, and that estimated value is used for classifying all observations. However, in classification problems, in addition to depending on the training sample, a good choice of k depends on the specific observation to be classified. Therefore, instead of using a fixed value of k over the entire measurement space, a spatially adaptive choice of k may be more useful in practice. This article presents one such adaptive nearest neighbor classification technique, where the value of k is selected depending on the distribution of competing classes in the vicinity of the observation to be classified. The utility of the proposed method has been illustrated using some simulated examples and well-known benchmark datasets. Asymptotic optimality of its misclassification rate has been derived under appropriate regularity conditions.     

Analysis of multivariate skew normal models with incomplete data

We establish computationally flexible methods and algorithms for the analysis of multivariate skew normal models when missing values occur in the data. To facilitate the computation and simplify the theoretic derivation, two auxiliary permutation matrices are incorporated into the model for the determination of observed and missing components of each observation. Under missing at random mechanisms, we formulate an analytically simple ECM algorithm for calculating parameter estimation and retrieving each missing value with a single-valued imputation. Gibbs sampling is used to perform a Bayesian inference on model parameters and to create multiple imputations for missing values. The proposed methodologies are illustrated through a real data set and comparisons are made with those obtained from fitting the normal counterparts.     

Joint Bayesian Analysis of Factor Scores and Structural Parameters in the Factor Analysis Model

A Bayesian approach is developed to assess the factor analysis model. Joint Bayesian estimates of the factor scores and the structural parameters in the covariance structure are obtained simultaneously. The basic idea is to treat the latent factor scores as missing data and augment them with the observed data in generating a sequence of random observations from the posterior distributions by the Gibbs sampler. Then, the Bayesian estimates are taken as the sample means of these random observations. Expressions for implementing the algorithm are derived and some statistical properties of the estimates are presented. Some aspects of the algorithm are illustrated by a real example and the performance of the Bayesian procedure is studied using simulation.     

Ultra-Permeable Dual-Mechanism-Driven Graphene Oxide Framework Membranes for Precision Ion Separations

Two-dimensional graphene oxide (GO) membranes are gaining popularity as a promising means to address global water scarcity. However, current GO membranes fail to sufficiently exclude angstrom-sized ions from solution. Herein, a de novo “posterior” interfacial polymerization (p-IP) strategy is reported to construct a tailor-made polyamide (PA) network in situ in an ultrathin GO membrane to strengthen size exclusion while imparting a positively charged membrane surface to repel metal ions. The electrostatic repulsion toward metal ions, coupled with the reinforced size exclusion, synergistically drives the high-efficiency metal ion separation through the synthesized positively charged GO framework (PC-GOF) membrane. This dual-mechanism-driven PC-GOF membrane exhibits superior metal ion rejection, anti-fouling ability, good operational stability, and ultra-high permeance (five times that of pristine GO membranes), enabling a sound step towards a sustainable water-energy-food nexus.