Production of nanometric particles in radio frequency glow discharges in mixtures of silane and methane

The formation of silicon particles in rf glow discharges has attracted attention due to their effect as a contaminant during film deposition or etching. However, silicon and silicon alloy powders produced by plasma¿enhanced chemical vapor deposition (PECVD) are promising new materials for sintering ceramics, for making nanoscale filters, or for supporting catalytic surfaces. Common characteristics of these powders are their high purity and the easy control of their stoichiometry through the composition of the precursor gas mixture. Plasma parameters also influence their structure. Nanometric powders of silicon¿carbon alloys exhibiting microstructural properties such as large hydrogen content and high surface/volume ratio have been produced in a PECVD reactor using mixtures of silane and methane at low pressure (-1 Torr) and low frequency square¿wave modulated rf power (13.56 MHz). The a¿Si1¿xCx:H powders were obtained from different precursor gas mixtures, from R=0.05 to R=9, where R=[SiH4]/([SiH4]+[CH4]). The structure of the a¿Si1¿xCx:H powder was analyzed by several techniques. The particles appeared agglomerated, with a wide size distribution between 5 and 100 nm. The silane/methane gas mixture determined the vibrational features of these powders in the infrared. Silicon-hydrogen groups were present for every gas composition, whereas carbon¿hydrogen and silicon¿carbon bonds appeared in methane¿rich mixtures (R-0.6). The thermal desorption of hydrogen revealed two main evolutions at about 375 and 660¿°C that were ascribed to hydrogen bonded to silicon and carbon, respectively. The estimated hydrogen atom concentration in the sample was about 50%.

Automatic filtering and substantiation of drug safety signals

Drug safety issues pose serious health threats to the population and constitute a major cause of mortality worldwide. Due to the prominent implications to both public health and the pharmaceutical industry, it is of great importance to unravel the molecular mechanisms by which an adverse drug reaction can be potentially elicited. These mechanisms can be investigated by placing the pharmaco-epidemiologically detected adverse drug reaction in an information-rich context and by exploiting all currently available biomedical knowledge to substantiate it. We present a computational framework for the biological annotation of potential adverse drug reactions. First, the proposed framework investigates previous evidences on the drug-event association in the context of biomedical literature (signal filtering). Then, it seeks to provide a biological explanation (signal substantiation) by exploring mechanistic connections that might explain why a drug produces a specific adverse reaction. The mechanistic connections include the activity of the drug, related compounds and drug metabolites on protein targets, the association of protein targets to clinical events, and the annotation of proteins (both protein targets and proteins associated with clinical events) to biological pathways. Hence, the workflows for signal filtering and substantiation integrate modules for literature and database mining, in silico drug-target profiling, and analyses based on gene-disease networks and biological pathways. Application examples of these workflows carried out on selected cases of drug safety signals are discussed. The methodology and workflows presented offer a novel approach to explore the molecular mechanisms underlying adverse drug reactions

Frequency of severe pulmonary hypertension complicating "isolated" atrial septal defect in infancy.

Atrial septal defects (ASDs) are typically asymptomatic in infancy and early childhood, and elective defect closure is usually performed at ages of 4 to 6 years. Severe pulmonary hypertension (PH) complicating an ASD is seen in adulthood and has only occasionally been reported in small children. A retrospective study was undertaken to evaluate the incidence of severe PH complicating an isolated ASD and requiring early surgical correction. During a 10-year period (1996 to 2006), 355 pediatric patients underwent treatment for isolated ASDs either surgically or by catheter intervention at 2 tertiary referral centers. Two hundred ninety-seven patients had secundum ASDs, and 58 had primum ASDs with mild to moderate mitral regurgitation. Eight infants were found with isolated ASDs (6 with secundum ASDs and 2 with primum ASDs) associated with significant PH, accounting for 2.2% of all patients with ASDs at the centers. These 8 infants had invasively measured pulmonary artery pressures of 50% to 100% of systemic pressure. They were operated in the first year of life and had complicated postoperative courses requiring specific treatment for PH for up to 16 weeks postoperatively. The ultimate outcomes in all 8 infants were good, with persistent normalization of pulmonary pressures during midterm follow-up of up to 60 months (median 28). All other patients with ASDs had normal pulmonary pressures, and the mean age at defect closure was significantly older, at 6.2 years for secundum ASDs and 3.2 years for primum ASDs. In conclusion, ASDs were rarely associated with significant PH in infancy but then required early surgery and were associated with excellent midterm outcomes in these patients.

Plant Size and Frequency of Strike, December 1970

In Illinois and Iowa, the author finds that plants with approximately 750 employees have suffered the highest strike-frequency rate. Why at this size? Among other explanations, it is posited that in significantly smaller plants labor-management relations can be personalized-and tensions reduced-while in appreciably larger plants sophistication in dealing with disputes may, of necessity, have been developed. C. Fred Eisele is a graduate teaching assistant at the University of Iowa's College of Business Administration.

Exposure to radio-frequency electromagnetic fields from broadcast transmitters and risk of childhood cancer: a census-based cohort study.

We investigated the association between exposure to radio-frequency electromagnetic fields (RF-EMFs) from broadcast transmitters and childhood cancer. First, we conducted a time-to-event analysis including children under age 16 years living in Switzerland on December 5, 2000. Follow-up lasted until December 31, 2008. Second, all children living in Switzerland for some time between 1985 and 2008 were included in an incidence density cohort. RF-EMF exposure from broadcast transmitters was modeled. Based on 997 cancer cases, adjusted hazard ratios in the time-to-event analysis for the highest exposure category (>0.2 V/m) as compared with the reference category (<0.05 V/m) were 1.03 (95% confidence interval (CI): 0.74, 1.43) for all cancers, 0.55 (95% CI: 0.26, 1.19) for childhood leukemia, and 1.68 (95% CI: 0.98, 2.91) for childhood central nervous system (CNS) tumors. Results of the incidence density analysis, based on 4,246 cancer cases, were similar for all types of cancer and leukemia but did not indicate a CNS tumor risk (incidence rate ratio = 1.03, 95% CI: 0.73, 1.46). This large census-based cohort study did not suggest an association between predicted RF-EMF exposure from broadcasting and childhood leukemia. Results for CNS tumors were less consistent, but the most comprehensive analysis did not suggest an association.

Reciprocal Translocations in Cattle: frequency estimation

Chromosomal anomalies, like Robertsonian and reciprocal translocations represent a big problem in cattle breeding as their presence induces, in the carrier subjects, a well documented fertility reduction. In cattle reciprocal translocations (RCPs, a chromosome abnormality caused by an exchange of material between nonhomologous chromosomes) are considered rare as to date only 19 reciprocal translocations have been described. In cattle it is common knowledge that the Robertsonian translocations represent the most common cytogenetic anomalies, and this is probably due to the existence of the endemic 1;29 Robertsonian translocation. However, these considerations are based on data obtained using techniques that are unable to identify all reciprocal translocations and thus their frequency is clearly underestimated. The purpose of this work is to provide a first realistic estimate of the impact of RCPs in the cattle population studied, trying to eliminate the factors which have caused an underestimation of their frequency so far. We performed this work using a mathematical as well as a simulation approach and, as biological data, we considered the cytogenetic results obtained in the last 15 years. The results obtained show that only 16% of reciprocal translocations can be detected using simple Giemsa techniques and consequently they could be present in no less than 0,14% of cattle subjects, a frequency five times higher than that shown by de novo Robertsonian translocations. This data is useful to open a debate about the need to introduce a more efficient method to identify RCP in cattle.

Cooperating pre-T-cell receptor and TCF-1-dependent signals ensure thymocyte survival.

Intrathymic T-cell maturation critically depends on the selective expansion of thymocytes expressing a functionally rearranged T-cell receptor (TCR) beta chain. In addition, TCR-independent signals also contribute to normal T-cell development. It is unclear whether and how signals from the 2 types of pathways are integrated. Here, we show that T-cell factor-1 (TCF-1), a nuclear effector of the canonical wingless/int (wnt)/catenin signaling pathway, ensures the survival of proliferating, pre-TCR(+) thymocytes. The survival of pre-TCR(+) thymocytes requires the presence of the N-terminal catenin-binding domain in TCF-1. This domain can bind the transcriptional coactivator beta-catenin and may also bind gamma-catenin (plakoglobin). However, in the absence of gamma-catenin, T-cell development is normal, supporting a role for beta-catenin. Signaling competent beta-catenin is present prior to and thus arises independently from pre-TCR signaling and does not substantially increase on pre-TCR signaling. In contrast, pre-TCR signaling significantly induces TCF-1 expression. This coincides with the activation of a wnt/catenin/TCF reporter transgene in vivo. Collectively, these data suggest that efficient TCF-dependent transcription requires that pre-TCR signaling induces TCF-1 expression, whereas wnt signals may provide the coactivator such as beta-catenin. The 2 pathways thus have to cooperate to ensure thymocyte survival at the pre-TCR stage.

Blind channel deconvolution of real world signals using source separation techniques

In this paper we present a method for blind deconvolution of linear channels based on source separation techniques, for real word signals. This technique applied to blind deconvolution problems is based in exploiting not the spatial independence between signals but the temporal independence between samples of the signal. Our objective is to minimize the mutual information between samples of the output in order to retrieve the original signal. In order to make use of use this idea the input signal must be a non-Gaussian i.i.d. signal. Because most real world signals do not have this i.i.d. nature, we will need to preprocess the original signal before the transmission into the channel. Likewise we should assure that the transmitted signal has non-Gaussian statistics in order to achieve the correct function of the algorithm. The strategy used for this preprocessing will be presented in this paper. If the receiver has the inverse of the preprocess, the original signal can be reconstructed without the convolutive distortion.

Coherency and sharpness measures by using ICA algorithms. An investigation for Alzheimer’s disease discrimination

In this paper, we present a comprehensive study of different Independent Component Analysis (ICA) algorithms for the calculation of coherency and sharpness of electroencephalogram (EEG) signals, in order to investigate the possibility of early detection of Alzheimer’s disease (AD). We found that ICA algorithms can help in the artifact rejection and noise reduction, improving the discriminative property of features in high frequency bands (specially in high alpha and beta ranges). In addition to different ICA algorithms, the optimum number of selected components is investigated, in order to help decision processes for future works.

Investigation of ICA algorithms for feature extraction of EEG signals in discrimination of Alzheimer disease

In this paper we present a quantitative comparisons of different independent component analysis (ICA) algorithms in order to investigate their potential use in preprocessing (such as noise reduction and feature extraction) the electroencephalogram (EEG) data for early detection of Alzhemier disease (AD) or discrimination between AD (or mild cognitive impairment, MCI) and age-match control subjects.

Correlations between negative-induced cerebral dynamics and idiopathic intellectual disability: an EEG study

Intellectual disability has long been associated with deficits in socio-emotional processing. However, studies investigating brain dynamics of maladaptive socio-emotional skills associated with intellectual disability are scarce. Here, we compared differences in brain activity between low intelligence quotient (I.Q.<75, N=13) and normal controls (N=15) while evaluating their subjective emotions. Positive (P) and negative (N) valenced pictures were presented one at a time to participants of both groups, at a rate of ¾. The task required that each participant evaluate their subjective emotion and press a predefined push-button when done, alternatively P and N. Electroencephalographic (EEG) signals were continuously recorded, and the 1000ms time window following each picture was analyzed offline for power in frequency domain. Alpha low (8-10Hz) and upper (10-13Hz) frequency bands were then compared for both groups and for both P and N emotions in 12 distributed scalp electrodes. The qualitative evaluation of emotions was similar between both groups, with constant longer reaction times for the low IQ participants. The EEG signal comparison shows marked power decrease in upper alpha frequency range for N emotions in low intelligence group. Otherwise no significant difference was noticed between low and normal IQ. Main findings of the present study are (1) results do not support the hypothesis that impairment in developmental intelligence roots in maladaptive emotional processing; (2) the strong alpha power suppression during negative-induced emotions suggests the involvement of an extended neural network and more effortful inhibition processes than positive ones. We call for further studies with a larger sample.

Orchestration signals in the classroom: managing the jigsaw collaborative learning flow

The orchestration of collaborative learning processes in face-to-facephysical settings, such as classrooms, requires teachers to coordinate students indicating them who belong to each group, which collaboration areas areassigned to each group, and how they should distribute the resources or roles within the group. In this paper we present an Orchestration Signal system,composed of wearable Personal Signal devices and an Orchestration Signal manager. Teachers can configure color signals in the manager so that they are transmitted to the wearable devices to indicate different orchestration aspects.In particular, the paper describes how the system has been used to carry out a Jigsaw collaborative learning flow in a classroom where students received signals indicating which documents they should read, in which group they were and in which area of the classroom they were expected to collaborate. The evaluation results show that the proposed system facilitates a dynamic, visual and flexible orchestration.

Frequency and chronology of extraintestinal manifestations in the Swiss Inflammatory Bowel Disease Cohort

Background: Data on the frequency of extraintestinal manifestations (EIM) in inflammatory bowel disease (IBD) is scarce, especially the one evaluating the time of occurrence of the EIM relative to IBD diagnosis. Aim: To assess the type and frequency of EIM in IBD patients and to evaluate when EIMs occur relative to IBD diagnosis. Methods: Analysis of data from the Swiss Inflammatory Bowel Disease Cohort (SIBDCS) which collects data on a large sample of IBD patients from hospitals and private practices across Switzerland starting in 2005. While parametric data are shown as mean ± SD, non-parametric data are presented as median and interquartile range (IQR). Results: A total of 1143 patients were analyzed (572 (50%) female, mean age 42.1 ± 14.4 years): 629 (55%) with Crohn's disease (CD), 501 (44%) with ulcerative colitis (UC), and 13 (1%) with indeterminate colitis (IC). Of 1143 patients, 374 (32.7%) presented with EIM (65% with CD, 33% with UC, 2% with IC). Of those patients suffering from EIMs, 37.4% presented with one, 41.7% with two, 12.4% with three, 5.3% with four, and 3.2% with five EIM during their lifetime. The IBD patients initially presented with the following EIMs: peripheral arthritis (PA) 63.4%, ankylosing spondylitis (AS) 8.1%, primary sclerosing cholangitis (PSC) 6.0%, uveitis 5.7%, oral aphthosis 5.7%, erythema nodosum (EN) 5.0%, pyoderma gangrenosum 1.8%, psoriasis 0.7%. While 92.9% of EIM occurred once IBD diagnosis was established (median 72 months, IQR 9-147 months, p < 0.001), 7.1% of EIMs preceded IBD diagnosis (median time 28 months before IBD diagnosis, IQR 7-60 months). Over a course of a lifetime, IBD patients presented with the following EIM (total exceeds 100 due to potential presence of multiple EIM): peripheral arthritis 69.3%, oral aphthosis 23%, ankylosing spondylitis 19.4%, uveitis 15.5%, erythema nodosum 14.5%, PSC 7.8%, pyoderma gangrenosum 6%, psoriasis 2.8%. Conclusion: EIMs frequently occur in a lifetime of IBD patients. The vast majority of patients present with EIMs once IBD diagnosis has been established. IBD patients most often present with peripheral arthritis, ankylosing spondylitis and PSC as their first EIM. However, peripheral arthritis, oral aphthosis, and ankylosing spondylitis are the most common EIMs in a lifetime of IBD patients.

Techniques for Estimating Flood-Frequency Discharges for Streams in Iowa, HR-395A, 2001

A statewide study was conducted to develop regression equations for estimating flood-frequency discharges for ungaged stream sites in Iowa. Thirty-eight selected basin characteristics were quantified and flood-frequency analyses were computed for 291 streamflow-gaging stations in Iowa and adjacent States. A generalized-skew-coefficient analysis was conducted to determine whether generalized skew coefficients could be improved for Iowa. Station skew coefficients were computed for 239 gaging stations in Iowa and adjacent States, and an isoline map of generalized-skew-coefficient values was developed for Iowa using variogram modeling and kriging methods. The skew map provided the lowest mean square error for the generalized-skew- coefficient analysis and was used to revise generalized skew coefficients for flood-frequency analyses for gaging stations in Iowa. Regional regression analysis, using generalized least-squares regression and data from 241 gaging stations, was used to develop equations for three hydrologic regions defined for the State. The regression equations can be used to estimate flood discharges that have recurrence intervals of 2, 5, 10, 25, 50, 100, 200, and 500 years for ungaged stream sites in Iowa. One-variable equations were developed for each of the three regions and multi-variable equations were developed for two of the regions. Two sets of equations are presented for two of the regions because one-variable equations are considered easy for users to apply and the predictive accuracies of multi-variable equations are greater. Standard error of prediction for the one-variable equations ranges from about 34 to 45 percent and for the multi-variable equations range from about 31 to 42 percent. A region-of-influence regression method was also investigated for estimating flood-frequency discharges for ungaged stream sites in Iowa. A comparison of regional and region-of-influence regression methods, based on ease of application and root mean square errors, determined the regional regression method to be the better estimation method for Iowa. Techniques for estimating flood-frequency discharges for streams in Iowa are presented for determining ( 1) regional regression estimates for ungaged sites on ungaged streams; (2) weighted estimates for gaged sites; and (3) weighted estimates for ungaged sites on gaged streams. The technique for determining regional regression estimates for ungaged sites on ungaged streams requires determining which of four possible examples applies to the location of the stream site and its basin. Illustrations for determining which example applies to an ungaged stream site and for applying both the one-variable and multi-variable regression equations are provided for the estimation techniques.

Effects of Reduced Intersection Lighting on Nighttime Accident Frequency, HR-1003A, 1977

The first phase of the study of intersection lighting and accidents conducted using data from 1964 through 1971 yielded the conclusion that the installation of intersection lighting reduced the nighttime accident frequency by 52%. With this conclusion, this project (the second phase), was initiated to determine the relative benefit of a higher level of lighting as opposed to minimum lighting. Twenty pairs of intersections with similar geometrics were selected. Some lights were turned out at one intersection of each pair to produce a lighting level differential. Based on the results of this research, the lighting level of lighted rural at-grade intersections does not have a significant effect on the accident frequency. At the nineteen "reduced lighting" intersections, the number of lighted luminaires was reduced from 101 to 46 with a corresponding reduction in energy consumption of over 100,000 Kilowatt hours per year. This energy conservation measure could reduce consumption by an estimated 1,000,000 Kilowatt hours per year if initiated on more than 200 earlier primary, rural installations.