Visualization of EEG using time-frequency distributions

The EEG is a time-varying or nonstationary signal. Frequency and amplitude are two of its significant characteristics, and are valuable clues to different states of brain activity. Detection of these temporal features is important in understanding EEGs. Commonly, spectrograms and AR models are used for EEG analysis. However, their accuracy is limited by their inherent assumption of stationarity and their trade-off between time and frequency resolution. We investigate EEG signal processing using existing compound kernel time-frequency distributions (TFDs). By providing a joint distribution of signal intensity at any frequency along time, TFDs preserve details of the temporal structure of the EEG waveform, and can extract its time-varying frequency and amplitude features. We expect that this will have significant implications for EEG analysis and medical diagnosis.     

Microenvironmental factors regulate Ly-6 A/E expression on PyV-transformed BALB/c 3T3 cells

Ouabain-induced changes of the free cytoplasmic Na+ concentration ([Na+]i) were monitored in aggregates of cells prepared from beta-cell-rich pancreatic mouse islets and the results were compared with the total islet content of sodium. The steady-state [Na+]i was lower in 20 mM glucose (11 mM) than in 3 mM glucose (14 mM). In the presence of 3 mM glucose the addition of 1 mM ouabain resulted in a rise in [Na+]i with an initial rate of 1.5 mM/min. However, the increase of total sodium corresponded to 2.8 mM/min, suggesting that rapid binding and/or sequestration of Na+ are prominent features for pancreatic beta-cells. Elevation of the glucose concentration to 20 mM increased the rate of ouabain-dependent rise of [Na+]i. The effect of glucose was mimicked by 1 mM tolbutamide or 100 microM carbachol and was counteracted by 100 nM of the alpha 2-adrenergic agonist clonidine. Glucose also accelerated the lowering of [Na+]i after withdrawal of ouabain. In promoting not only the entry but also the extrusion of Na+, glucose actually enhances the turnover of the ion in pancreatic beta-cells.     

High incidence of adeno- and polyomavirus-induced hemorrhagic cystitis in bone marrow allotransplantation for hematological malignancy following T cell depletion and cyclosporine

Retrosternal goiter is defined as any goiter in which at least 50 per cent of the thyroid resides below the level of the thoracic inlet. The incidence of retrosternal goiter varies from 3 to 20 per cent with respect to thyroidectomy patients. A retrospective chart review from June 1991 to December 1997 found 232 thyroidectomies performed at our institution. Sixteen patients were found to have retrosternal goiters (6.9%). The mean age was 57.8 years (range, 34-92). All were of benign pathology. Symptoms included shortness of breath (68.8%), hoarseness (37.5%), dysphagia (31.3%), and superior vena cava obstruction (6.25%). Thirteen patients were female (81.3%). Fifteen patients had surgical intervention (93.8%). Total thyroidectomy was performed in nine cases (60%), whereas lobectomy was performed in six cases (40%). All treated patients had complete resolution of symptoms. A cervical incision alone was used in 13 cases (86.7%). Complications consisted of one postoperative pleural effusion and in one case a traumatic C5 nerve root compression occurred. There were no instances of long-term vocal cord paralysis or hypoparathyroidism. There was no perioperative mortality. In the majority of patients with retrosternal goiter, surgery can be done expeditiously through a cervical incision with minimal morbidity and mortality.     

The Drosophila embryonic midline is the site of Spitz processing, and induces activation of the EGF receptor in the ventral ectoderm

The Drosophila EGF receptor (DER) is activated by secreted Spitz to induce different cell fates in the ventral ectoderm. Processing of the precursor transmembrane Spitz to generate the secreted form was shown to be the limiting event, but the cells in which processing takes place and the mechanism that may generate a gradient of secreted Spitz in the ectoderm were not known. The ectodermal defects in single minded (sim) mutant embryos, in which the midline fails to develop, suggested that the midline cells contribute to patterning of the ventral ectoderm. This work shows that the midline provides the site for Spitz expression and processing. The Rhomboid and Star proteins are also expressed and required in the midline. The ectodermal defects of spitz, rho or Star mutant embryos could be rescued by inducing the expression of the respective normal genes only in the midline cells. Rho and Star thus function non-autonomously, and may be required for the production or processing of the Spitz precursor. Secreted Spitz is the only sim-dependent contribution of the midline to patterning the ectoderm, since the ventral defects observed in sim mutant embryos can be overcome by expression of secreted Spitz in the ectoderm. While ectopic expression of secreted Spitz in the ectoderm or mesoderm gave rise to ventralization of the embryo, increased expression of secreted Spitz in the midline did not lead to alterations in ectoderm patterning. A mechanism for adjustment to variable levels of secreted Spitz emanating from the midline may be provided by Argos, which forms an inhibitory feedback loop for DER activation. The production of secreted Spitz in the midline, may provide a stable source for graded DER activation in the ventral ectoderm.     

Severe rhabdomyolysis with renal failure after intranasal cocaine use

Torsion of a long bone is the twist along its longitudinal axis; torsion of the radius is defined by the angle between the proximal and distal metaphyses in the transverse plane. Measurement of the radial torsion angle provides a means of detection and quantification of malrotation after a fracture. The purpose of the current study was to develop and standardize a technique for the measurement of torsion of the radius. Axial computerized tomographic images of thirty-nine pairs of dry cadaver specimens of normal radii, and an additional four pairs of radii with a unilateral deformity of the distal metaphysis that was consistent with a previous fracture, were studied and a measurement protocol was established. The radial torsion angle was measured by three independent observers on two separate occasions. Reproducibility of the technique was determined with use of the intraclass correlation coefficient to express both interobserver and intraobserver reliability. Consistency of measurements between observers and by the same observer was high, with intraclass correlation coefficients ranging from 0.87 to 0.94. The mean torsion angle for the eighty-two normal radii in the study was 32.6 degrees (95 per cent confidence interval of the mean, 30.3 to 34.9 degrees; range, 1.4 to 58.8 degrees). There were small variations in torsion angle between the two radii of each normal pair (mean side-to-side difference, 4.9 degrees; 95 per cent confidence interval of the mean, 3.5 to 6.3 degrees). The mean torsion angle of the four radii with a malunited fracture was 10.4 degrees (95 per cent confidence interval of the mean, 5.7 to 15.1 degrees), and the mean side-to-side difference in the pairs containing these radii was 24.1 degrees (95 per cent confidence interval of the mean, 8.5 to 39.6 degrees; p < 0.0001 compared with the normal radii).     

Customers’ preference of online store visit strategies: an investigation of demographic variables

There is significant interest among marketers and academics to understand how to segment online consumers to better fulfill their needs. Previous literature on brick-and-mortar shopping has advocated demographic variables as simple yet valuable indicators to understand consumers and segment them accordingly. However, research in the online shopping context has produced mixed findings about the effects of demographics, which limit their utility to online merchants. As an attempt to address the ambiguity, the study proposes a more comprehensive approach to investigate the effects of demographic variables in the online shopping context. This is done by considering the demographic variables in combinations and using clickstream data to more accurately derive online shoppers’ surfing behaviour for segmentation purposes. Following this approach, our study investigates the effects of the demographic variables of gender, age, income, and education, based on the theories of media naturalness and consumer trait and involvement. The results reveal various effects of age, income, and education on online consumers’ needs being reflected in their store visit strategies. Implications are suggested for e-commerce research and practice.     

纳米CaCO_3/PVC共混体系的研究

研究了纳米级CaCO3 粒子的微观形态 ,以及纳米CaCO3/PVC共混体系的流变性能和力学性能。结果表明 ,纳米CaCO3 加入量为 9质量份时 ,纳米CaCO3/PVC共混体系的缺口冲击强度可达到 31 4kJ/m2 。纳米Ca CO3 对PVC共混体系具有显著的增韧效果     

Structure-based discovery and experimental verification of novel AI-2 quorum sensing inhibitors against Vibrio harveyi

Quorum sensing has been implicated in the control of pathologically relevant bacterial behavior such as secretion of virulence factors, biofilm formation, sporulation, and swarming motility. The AI-2 quorum sensing pathway is found in both gram-positive and gram-negative bacteria. Therefore, antagonizing AI-2 quorum sensing is a possible approach to modifying bacterial behaviour. However, efforts in developing inhibitors of AI-2-mediated quorum sensing are especially lacking. High-throughput virtual screening using the V. harveyi LuxP crystal structure identified two compounds that were found to antagonize AI-2-mediated quorum sensing in V. harveyi without cytotoxicity. The sulfone functionality of these inhibitors was identified as critical to their ability to mimic the natural ligand in their interactions with Arg 215 and Arg 310 of the active site.