Automatic region of interest determination in dual photon absorptiometry of the lumbar spine

In a heuristic approach, the authors developed an algorithm for automatic region-of-interest (ROI) determination in bone mineral density (BMD) measurements of the lumbar spine. First, the algorithm detects the boundaries of the spine utilizing simple smoothing and gradient operators followed by a dynamic programming technique. Second, it selects L2, L3, and L4 from the spine by examining the BMD values along lines that are orthogonal to the local direction of the spine. The algorithm was tested in studies of a spine phantom, normal subjects (30), and patients (94). In all but two patient studies of severely affected spines the contours were detected correctly. The ROI determination was performed satisfactorily in all studies of the phantom, normals, and patients that had no spinal fractures. The coefficient of variation (CV) in the phantom studies was equal to 0.7%. In duplicate studies of 15 normal subjects and nine patients, the CV was equal to 1.0 and 2.7%, respectively. Compared to manual determination of the ROI, the precision of BMD measurements was clearly improved by the automatic procedure.     

Comments on Frey's "Data analysis reveals significant microwave-induced eye damage in humans"

Frey's critique and analysis of the Appleton-McCrossan and Appleton et al studies were examined. Frey is criticized for: ignoring pooling problems in his chi-square test; not analyzing the opacity data in Appleton et al; not analyzing the data on vacuoles and posterior subcapsular iridescence in Appleton and McCrossan and Appleton et al; and failing to do log-linear analysis which is appropriate for the design in the two studies. Application of log-linear tests to the opacity data in both studies leads to the conclusion that subject age was significantly associated with the occurrence of opacities, but, contrary to Frey's conclusion, microwave radiation was not.     

Assessment of SPM in perfusion brain SPECT studies. A numerical simulation study using bootstrap resampling methods

Statistical parametric mapping (SPM) has become the technique of choice to statistically evaluate positron emission tomography (PET), functional magnetic resonance imaging (fMRI), and single photon emission computed tomography (SPECT) functional brain studies. Nevertheless, only a few methodological studies have been carried out to assess the performance of SPM in SPECT. The aim of this paper was to study the performance of SPM in detecting changes in regional cerebral blood flow (rCBF) in hypo- and hyperperfused areas in brain SPECT studies. The paper seeks to determine the relationship between the group size and the rCBF changes, and the influence of the correction for degradations. The assessment was carried out using simulated brain SPECT studies. Projections were obtained with Monte Carlo techniques, and a fan-beam collimator was considered in the simulation process. Reconstruction was performed by using the ordered subsets expectation maximization (OSEM) algorithm with and without compensation for attenuation, scattering, and spatial variant collimator response. Significance probability maps were obtained with SPM2 by using a one-tailed two-sample f-test. A bootstrap resampling approach was used to determine the sample size for SPM to detect the between-group differences. Our findings show that the correction for degradations results in a diminution of the sample size, which is more significant for small regions and low-activation factors. Differences in sample size were found between hypo- and hyperperfusion. These differences were larger for small regions and low-activation factors, and when no corrections were included in the reconstruction algorithm.     

Analog circuit for real-time computation of respiratory mechanicalimpedance in sleep studies

The aim of this work was to develop a low-cost circuit for real-time analog computation of the respiratory mechanical impedance in sleep studies. The practical performance of the circuit was tested in six patients with obstructive sleep apnea. The impedance signal provided by the analog circuit was compared with the impedance calculated simultaneously with a conventional computerized system. The authors concluded that the low-cost analog circuit developed could be a useful tool for facilitating the real-time assessment of airway obstruction in routine sleep studies     

A Meta‐Analysis of Pornography Consumption and Actual Acts of Sexual Aggression in General Population Studies

Whether pornography consumption is a reliable correlate of sexually aggressive behavior continues to be debated. Meta‐analyses of experimental studies have found effects on aggressive behavior and attitudes. That pornography consumption correlates with aggressive attitudes in naturalistic studies has also been found. Yet, no meta‐analysis has addressed the question motivating this body of work: Is pornography consumption correlated with committing actual acts of sexual aggression? 22 studies from 7 different countries were analyzed. Consumption was associated with sexual aggression in the United States and internationally, among males and females, and in cross‐sectional and longitudinal studies. Associations were stronger for verbal than physical sexual aggression, although both were significant. The general pattern of results suggested that violent content may be an exacerbating factor.     

Synthesis,characterization and conducting properties of novel poly (vinyl cinnamate)/zinc oxide nanocomposites via in situ polymerization

New polymer nanocomposite based on poly (vinyl cinnamate) (PVCin) with zinc oxide (ZnO) was synthesized by in situ polymerization of vinyl cinnamate with different concentrations of ZnO nanoparticles. The composite was characterized through FT-IR, FT-Raman, UV spectroscopy, XRD, HRTEM, FE-SEM, DSC, TGA and electrical conductivity studies. The IR, Raman and UV spectra ascertained the structural variation of PVCin network by the insertion of nanoparticles within the polymer segment. The morphological studies by TEM and FE-SEM photographs indicate that the nanopowder was uniformly dispersed in the polymer. The presence of nanoparticles in the nanocomposite was clearly observed from the XRD studies and the ordered arrangement of nanoparticles within the macromolecular chain of PVCin increased with increase in concentration of nanofillers. DSC results showed that the glass transition temperature and crystalline melting point were increased smoothly with the increase in concentration of nanoparticles. Analysis of TGA studies showed a significant increase in thermal stability with an increase in weight percentage of nanoparticles. The DC conductivity of nanocomposite was increased by ten orders of magnitude with the addition of 7 wt% of nano ZnO inclusion. AC conductivity, dielectric constant and dielectric loss tangent of nanocomposite was remarkably increased with increase in ZnO content up to 7 wt% of filler particles. Both AC and DC conductivity and dielectric properties were decreased beyond 7 wt% loading.     

孕期维生素D水平与妊娠期糖尿病相关性—meta分析

目的:探讨孕期维生素D水平与妊娠期糖尿病(GDM)的关系。方法:检索PubMed、EMbase、MEDLINE、CENTRAL、CBM和CNKI数据库,收集有关孕期维生素D水平与妊娠期糖尿病关系的研究。采用NOS评分条目对文献质量进行评价,应用RevMan 5.0和Stata11.0软件对数据进行meta分析。结果:共纳入15项研究,9项研究为孕期维生素D营养状态与GDM的关系,结果显示GDM人群孕期维生素D缺乏和不足发生率均高于健康孕妇,OR值分别为1.78和1.46,P0.05。11项研究为孕期血25(OH)D3水平与GDM的关系,结果显示GDM人群血25(OH)D3水平低于健康对照,MD=-5.13,P0.05。结论:目前证据显示,孕期低维生素D水平可能与GDM有关,但是否为因果关系有待进一步研究。     

Elaboration in Processing Adolescent Health Messages: The Impact of Egocentrism and Sensation Seeking on Message Processing

The present studies explored how adolescents process information in making decisions about risk behavior. We studied two developmental aspects of adolescent egocentrism: personal fable (a sense of invulnerability) and imaginary audience (focus on others), along with individual difference variables (sensation seeking, self-esteem, and peer pressure). The studies investigated the effects of a message variable, elaboration demand, which is driven by a developmental view of adolescents' cognitive processing. Results of 3 studies indicated the deep elaboration message was partially effective in changing message perceptions and adolescents' intentions to behave in ways to reduce risks. The message type interacted with developmental indicators (age and cognitive development), gender, and topic to explain behavioral intentions, message perceptions and retention.     

玻璃酸钠配合中药熏洗治疗膝关节骨关节炎疗效的Meta分析

背景：国内应用玻璃酸钠配合中药熏洗治疗膝关节骨关节炎较为广泛,但临床研究报道多为小样本随机对照研究,缺乏循证医学方面的依据和说服力。目的：对应用玻璃酸钠配合中药熏洗治疗膝关节骨关节炎的疗效进行系统评价。方法：计算机检索Pubmed、Sciencedirect（so）数据库、重庆维普中文科技期刊全文数据库（VIP,1989／2010）和清华同方数据库（CNKI,1979／2010）,收集有关关节腔内注射玻璃酸钠配合中药熏洗与单独使用玻璃酸钠治疗膝关节骨关节炎相比较的随机对照实验（RCT）。评价纳入研究的方法学质量并进行资料提取后,采用RevMan5．1软件进行Meta分析。结果：共纳入18个RCT,包括2312例膝关节骨关节炎患者。Meta分析结果显示：治疗后玻璃酸钠配合中药熏洗组总有效率均高于单独使用玻璃酸钠组。结论：在改善膝关节功能方面,玻璃酸钠配合中药熏洗治疗效果远高于对照组;但在远期疗效方面优势不甚明显,尚需大样本高质量随机对照研究去进一步证实。     

A Versatile Current-Regulated Bidirectional Stimulator

Based on requirements specified by several investigators engaged in studies involving electrical stimulation through electrodes chronically implanted in brain substance, an electrical stimulator was designed and built. The instrumentation problems encountered in stimulation studies are discussed to emphasize the need for certain features adapting the instrument to the biophysical characteristics of living brain tissues. The resulting stimulator output is bidirectional, current-regulated and isolated, and provides isolated monitors for current ranges from 0.1 mA to 10 mA and pulses from 0.1 ms to 10 ms wide.     

Some characteristics of a cesium plasma cell

Many studies about cesium plasma cells have been reported, but it seemed to the authors that there were few in which one could combine experimental results with theoretical ones in the sense that these experimental studies were carried out only in an operating region of almost constant cathode work function, that is, considerably high cathode temperatures. Our measurements were done only in the region of low cathode temperature and low gas pressure in which the interelectrode spacing was less than the mean free path of electrons, in order to examine these theories. The efficiency agreed well with one of these theories. Open-circuit voltage was also observed.     

A framework for analyzing levels of analysis issues in studies of e-collaboration

There has been a proliferation of competing explanations regarding the inconsistent results reported by the e-collaboration literature since its inception. This study advances another possible explanation by investigating the range of multilevel issues that can be encountered in research on the use of synchronous or asynchronous group support systems. We introduce concepts of levels of analysis from the management literature and then examine all empirical studies of e-collaboration from seven information systems journals for the period 1999-2003. We identified a total of 54 studies of e-collaboration in these journals, and after excluding 18 nonconforming studies - those that were primarily conceptual, qualitative, or exploratory only-we analyzed the levels of analysis issues in the remaining 36 empirical studies. Based on our analysis and classification of these studies into six different clusters according to their levels of analysis, we found that a majority of these studies contain one or more problems of levels incongruence that cast doubts on the validity of their results. It is indeed possible that these methodological problems are in part responsible for the inconsistent results reported in this literature, especially since researchers' frequent decisions to analyze data at the individual level - even when the theory was formulated at the group level and when the research setting featured individuals working in groups -may very well have artificially inflated the authors' chances of finding statistically significant results. Based on our discussion of levels of analysis concepts, we hope to provide guidance to empirical researchers who study e-ollaboration.     

Interface defects and induced voltage contrast in SEM studies of bare SiO2---Si systems

During extensive SEM studies of discrete and integrated circuit bipolar transistors a regular occurrence of bright areas in the thick oxide image was observed. These areas had distinctive geometries ranging from straight lines to more complicated shapes. Experimental and theoretical studies indicate that the contrast features are associated with defects at or close to the SiO₂---Si interface. An electrostatic analysis combined with the experimental results has been used to show that a trapped electron change distribution exists in the oxide which is related to oxide structure.     

The effects of cultural dimension on ICT innovation: Empirical analysis of mobile phone services

ICT Innovation is one of the major forces for socioeconomic development. It is the key element to spur growth of the economy of a nation. Several studies have shown that culture is a crucial determinant of innovations. This study examines the effect of socio-cultural factors on ICT innovation with specific focus on the mobile banking services. Research was conducted on 220 respondents from sampled population in South Africa. The questionnaire used in this study was developed based on previous studies that have proven validity. The findings indicate that culture is an appropriate concept to describe how innovation in information and communication technology can be influenced by human behavior.     

A comparison of human and model observers in multislice LROC studies

Model and human observers have been compared in a series of localization receiver operating characteristic (LROC) studies involving single-slice and multislice image displays. The task was detection of Ga-avid lymphomas within single photon emission computed tomography (SPECT)-reconstructed transverse slices of a mathematical phantom, and the studies involved four reconstruction strategies: the filtered-backprojection (FBP) and ordered-subset expectation-maximization (OSEM) algorithms with two- and three-dimensional postreconstruction filtering. The human-observer data was drawn from studies performed by Wells et al. (2000), while multiclass versions of the nonprewhitening (NPW), channelized nonprewhitening (CNPW), and channelized Hotelling (CH) model observers, each capable of performing the tumor search task, were applied. The channelized observers were evaluated with multiple square-channel models and both with and without internal noise. For the multislice studies, two different capacities for integrating the slice information were also tested. The CH observer gave good quantitative agreement with the human data from both image-display studies when the internal-noise model was used. The CNPW observer performed similarly with the iterative strategies. Wells et al. had shown that human observers are imperfect integrators of multislice information, and this is characterized as increased internal noise with the model observers.     

A mechatronic platform for human touch studies

The development of a mechatronic tactile stimulation platform for touch studies is presented. The platform was developed for stimulation of the fingertip using textured surfaces, providing repeatable tangential sliding motion of stimuli with controlled indentation force. Particular requirements were addressed to make the platform suitable for neurophysiological studies in humans with particular reference to electrophysiological measurements, but allowing a variety of other studies too, such as psychophysical, tribological and artificial touch ones. The design of the mechatronic tactile stimulator is detailed, as well as the performance in tracking reference trajectories. Using microneurography, we recorded from human tactile afferents and validated the platform compatibility with the exacting demands of electrophysiological methods, comprising the absence of spurious vibrations and the lack of relevant electromagnetic interference.     

Human factors evaluation of calling procedures for the advanced mobile phone system (AMPS)

A series of laboratory studies conducted to identify the best calling procedures from the user's standpoint is described. The results of the studies have been incorporated into the Bell Laboratories AMPS control unit design recommendations. The primary constraint on such procedures was the preorigination dialing concept described.     

AFM Characterization of Raman Laser-Induced Damage on CdZnTe Crystal Surfaces

Raman laser studies of detector-grade CdZnTe crystals show an increase in intensity of the Te peaks of the Raman spectra even at very low laser powers. In this study, atomic force microscopy (AFM) was used to characterize the extent of damage to the CdZnTe crystal surface following exposure to the Raman laser. AFM images revealed localized surface damage in the areas exposed to the Raman laser beam. Additional studies using conductive-probe AFM techniques provided localized electrical information for the laser-induced Te-rich areas.     

Psychophysiological Measurement of Information Selection: Two Studies

These studies measured selective exposure to information by “open-and “closed-minded” subjects within a consistency perspective, using an eye camera to record actual exposure behaviors on discrepant, supportive, and balanced materials, presented simultaneously. Arousal (taken as an indicator of stress) of the subjects during exposure to each of the types of stimulus materials was measured through use of galvanic skin response equipment. These procedures were selected to overcome some of the principal questions about validity raised in regard to conventional methods in information selection studies.