Carriers escape mechanisms in shallow InGaAs/GaAs quantum wells grown on vicinal (001) GaAs substrates

We used photoluminescence spectroscopy in order to investigate the carriers escape mechanisms in In0.15Ga0.85As/GaAs quantum wells grown on top of nominal (001) and 2°-, 4°-and 6°-off (001) towards (111)A GaAs substrates. We described the escape processes using two models that fit the Arrhenius plot of the integrated PL intensity as a function of the inverse of the sample temperature. In the first model, we considered equal escape probability for electrons and holes. In the second one, we assumed that a single type of carrier can escape from the well. At high temperature, the first model fits the experimental data well, whereas, between 50 K and 100 K, the second model has to be taken into account to describe the data. We observed that the escape activation energy depends on the misorientation angle. An unusual behavior was noted when the full width at half maximum of the photoluminescence main emission was plotted as a function of the sample temperature. We showed that the escape process of the less-confined carriers drives this behavior. © 1999 Academic Press.

Preliminary core sets of measures for disease activity and damage assessment in juvenile systemic lupus erythematosus and juvenile dermatomyositis

Objective. To identify preliminary core sets of outcome variables for disease activity and damage assessment in juvenile systemic lupus erythematosus (JSLE) and juvenile dermatomyositis (JDM). Methods. Two questionnaire surveys were mailed to 267 physicians from 46 different countries asking each member to select and rank the response variables used when assessing clinical response in patients with JSLE or JDM. Next, 40 paediatric rheumatologists from 34 countries met and, using the nominal group technique, selected the domains to be included in the disease activity and damage core sets for JSLE and JDM. Results. A total of 41 response variables for JSLE and 37 response variables for JDM were selected and ranked through the questionnaire surveys. In the consensus conference, domains selected for both JSLE and JDM activity or damage core sets included the physician and parent/patient subjective assessments and a global score tool. Domains specific for JSLE activity were the immunological tests and the kidney function parameters. Concerning JDM, functional ability and muscle strength assessments were indicated for both activity and damage core sets, whereas serum muscle enzymes were included only in the activity core set. A specific paediatric domain called 'growth and development' was introduced in the disease damage core set for both diseases and the evaluation of health-related quality of life was advised in order to capture the influence of the disease on the patient lifestyle. Conclusions. We developed preliminary core sets of measures for disease activity and damage assessment in JSLE and JDM. The prospective validation of the core sets is in progress.

Juvenile localized scleroderma: Clinical and epidemiological features in 750 children. An international study

Objective. Juvenile localized scleroderma (JLS) includes a number of conditions often grouped together. With the long-term goal of developing uniform classification criteria, we studied the epidemiological, clinical and immunological features of children with JLS followed by paediatric rheumatology and dermatology centres. Methods. A large, multicentre, multinational study was conducted by collecting information on the demographics, family history, triggering environmental factors, clinical and laboratory features, and treatment of patients with JLS. Results. Seven hundred and fifty patients with JLS from 70 centres were enrolled into the study. The disease duration at diagnosis was 18 months. Linear scleroderma (LS) was the most frequent subtype (65%), followed by plaque morphea (PM) (26%), generalized morphea (GM) (7%) and deep morphea (DM) (2%). As many as 15% of patients had a mixed subtype. Ninety-one patients (12%) had a positive family history for rheumatic or autoimmune diseases; 100 (13.3%) reported environmental events as possible trigger. ANA was positive in 42.3% of the patients, with a higher prevalence in the LS-DM subtype than in the PM-GM subtype. Scl70 was detected in the sera of 3% of the patients, anticentromere antibody in 2%, anti-double-stranded DNA in 4%, anti-cardiolipin antibody in 13% and rheumatoid factor in 16%. Methotrexate was the drug most frequently used, especially during the last 5 yr. Conclusion. This study represents the largest collection of patients with JLS ever reported. The insidious onset of the disease, the delay in diagnosis, the recognition of mixed subtype and the better definition of the other subtypes should influence our efforts in educating trainees and practitioners and help in developing a comprehensive classification system for this syndrome. © 2006 Oxford University Press.

Methotrexate improves the health-related quality of life of children with juvenile idiopathic arthritis

Objectives: To examine the change in health-related quality of life (HRQOL) and its determinants in children with juvenile idiopathic arthritis (JIA) treated with methotrexate (MTX). Methods: Patients were extracted from the PRINTO clinical trial which aimed to evaluate the efficacy and safety profile of MTX administered in standard, intermediate or higher doses (10, 15 and 30 mg/m2/week respectively). Children with polyarticular-course JIA, who were less than 18 years and had a complete HRQOL assessment were included. Results: A total of 521 children were included. At baseline, patients with JIA showed poorer HRQOL (p<0.01) than healthy children. In 207/412 (50%) and 63 (15%) children, HRQOL values were 2 standard deviations below the mean of healthy controls in the physical and psychosocial summary scale, respectively. After 6 months of treatment with standard dose MTX, there was a statistically significant improvement in all HRQOL health concepts, particularly the physical ones. Similar improvements were observed in those who did not respond to a standard dose of MTX and were subsequently randomised to a higher dose. The presence of marked disability at baseline was associated with a fivefold increased risk of retaining poor physical health after 6 months of active treatment with standard dose MTX. Other less important determinants of retaining poor physical well-being were the baseline level of systemic inflammation, pain intensity and an antinuclear-antibody-negative status. Conclusions: MTX treatment produces a significant improvement across a wide range of HRQOL components, particularly in the physical domains, in patients with JIA.

The Ped-APS registry: The antiphospholipid syndrome in childhood

In recent years, antiphospholipid syndrome (APS) has been increasingly recognised in various paediatric autoimmune and nonautoimmune diseases, but the relatively low prevalence and heterogeneity of APS in childhood made it very difficult to study in a systematic way. The project of an international registry of paediatric patients with APS (the Ped-APS Registry) was initiated in 2004 to foster and conduct multicentre, controlled studies with large number of paediatric APS patients. The Ped-APS Registry is organised as a collaborative project of the European Forum on Antiphospholipid Antibodies and Juvenile Systemic Lupus Erythematosus Working Group of the Paediatric Rheumatology European Society. Currently, it documents a standardised clinical, laboratory and therapeutic data of 133 children with antiphospholipid antibodies (aPL)-related thrombosis from 14 countries. The priority projects for future research of the Ped-APS Registry include prospective enrolment of new patients with aPL-related thrombosis, assessment of differences between the paediatric and adult APS, evaluation of proinflammatory genotype as a risk factor for APS manifestations in childhood and evaluation of patients with isolated nonthrombotic aPL-related manifestations. © The Author(s), 2009.

Influence of voids in the hybrid layer based on self-etching adhesive systems: a 3-D FE analysis

The presence of porosities at the dentin/adhesive interface has been observed with the use of new generation dentin bonding systems. These porosities tend to contradict the concept that etching and hybridization processes occur equally and simultaneously. Therefore, the aim of this study was to evaluate the micromechanical behavior of the hybrid layer (HL) with voids based on a self-etching adhesive system using 3-D finite element (FE) analysis. Three FE models (Mr) were built: Mr, dentin specimen (41x41x82 μm) with a regular and perfect (i.e. pore-free) HL based on a self-etching adhesive system, restored with composite resin; Mp, similar to M, but containing 25% (v/v) voids in the HL; Mpp, similar to Mr, but containing 50% (v/v) voids in the HL. A tensile load (0.03N) was applied on top of the composite resin. The stress field was obtained by using Ansys Workbench 10.0. The nodes of the base of the specimen were constrained in the x, y and z axes. The maximum principal stress (σmax) was obtained for all structures at the dentin/adhesive interface. The Mpp showed the highest peak of σmax in the HL (32.2 MPa), followed by Mp (30 MPa) and Mr (28.4 MPa). The stress concentration in the peritubular dentin was high in all models (120 MPa). All other structures positioned far from voids showed similar increase of stress. Voids incorporated into the HL raised the σmax in this region by 13.5%. This behavior might be responsible for lower bond strengths of self-etching and single-bottle adhesives, as reported in the literature.

Measurement of the charge ratio of atmospheric muons with the CMS detector

We present a measurement of the ratio of positive to negative muon fluxes from cosmic ray interactions in the atmosphere, using data collected by the CMS detector both at ground level and in the underground experimental cavern at the CERN LHC. Muons were detected in the momentum range from 5 GeV/. c to 1 TeV/. c. The surface flux ratio is measured to be 1.2766±0.0032(stat.)±0.0032(syst.), independent of the muon momentum, below 100 GeV/. c. This is the most precise measurement to date. At higher momenta the data are consistent with an increase of the charge ratio, in agreement with cosmic ray shower models and compatible with previous measurements by deep-underground experiments. © 2010.

Measurement of the muon stopping power in lead tungstate

A large sample of cosmic ray events collected by the CMS detector is exploited to measure the specific energy loss of muons in the lead tungstate (PbWO4) of the electromagnetic calorimeter. The measurement spans a momentum range from 5 GeV/c to 1 TeV/c. The results are consistent with the expectations over the entire range. The calorimeter energy scale, set with 120 GeV/c electrons, is validated down to the sub-GeV region using energy deposits, of order 100 MeV, associated with low-momentum muons. The muon critical energy in PbWO4 is measured to be 160+5 -68 GeV, in agreement with expectations. This is the first experimental determination of muon critical energy. © 2010 IOP Publishing Ltd and SISSA.

Commissioning of the CMS experiment and the cosmic run at four tesla

The CMS Collaboration conducted a month-long data-taking exercise known as the Cosmic Run At Four Tesla in late 2008 in order to complete the commissioning of the experiment for extended operation. The operational lessons resulting from this exercise were addressed in the subsequent shutdown to better prepare CMS for LHC beams in 2009. The cosmic data collected have been invaluable to study the performance of the detectors, to commission the alignment and calibration techniques, and to make several cosmic ray measurements. The experimental setup, conditions, and principal achievements from this data-taking exercise are described along with a review of the preceding integration activities. © 2010 IOP Publishing Ltd and SISSA.

Performance of the CMS Level-1 trigger during commissioning with cosmic ray muons and LHC beams

The CMS Level-1 trigger was used to select cosmic ray muons and LHC beam events during data-taking runs in 2008, and to estimate the level of detector noise. This paper describes the trigger components used, the algorithms that were executed, and the trigger synchronisation. Using data from extended cosmic ray runs, the muon, electron/photon, and jet triggers have been validated, and their performance evaluated. Efficiencies were found to be high, resolutions were found to be good, and rates as expected. © 2010 IOP Publishing Ltd and SISSA.

Performance of the CMS drift-tube chamber local trigger with cosmic rays

The performance of the Local Trigger based on the drift-tube system of the CMS experiment has been studied using muons from cosmic ray events collected during the commissioning of the detector in 2008. The properties of the system are extensively tested and compared with the simulation. The effect of the random arrival time of the cosmic rays on the trigger performance is reported, and the results are compared with the design expectations for proton-proton collisions and with previous measurements obtained with muon beams. © 2010 IOP Publishing Ltd and SISSA.

Fine synchronization of the CMS muon drift-tube local trigger using cosmic rays

The CMS experiment uses self-triggering arrays of drift tubes in the barrel muon trigger to perform the identification of the correct bunch crossing. The identification is unique only if the trigger chain is correctly synchronized. In this paper, the synchronization performed during an extended cosmic ray run is described and the results are reported. The random arrival time of cosmic ray muons allowed several synchronization aspects to be studied and a simple method for the fine synchronization of the Drift Tube Local Trigger at LHC to be developed. © 2010 IOP Publishing Ltd and SISSA.