Biomedical subjects

A Brandt

Publications and source records attributed to A Brandt.

At least 55 records · Page 3Linked to original sources

PubMed2003

Search for large extra dimensions in the monojet+E(T) channel with the DØ detector.

We present a search for large extra dimensions (ED) in pp collisions at a center-of-mass energy of 1.8 TeV using data collected by the DØ detector at the Fermilab Tevatron in 1994-1996. Data corresponding to 78.8+/-3.9 pb(-1) are examined for events with large missing transverse energy, one high-p(T) jet, and no isolated muons. There is no excess observed beyond expectation from the standard model, and we place lower limits on the fundamental Planck scale of 1.0 and 0.6 TeV for 2 and 7 ED, respectively.

Journal Article↗

PubMed2003

Satisfaction with rollators among community-living users: a follow-up study.

PURPOSE: Rollators are used in order to make mobility possible for people with restricted walking ability. The use of rollators is increasing, but little is known about outcomes. The aim of this study was to investigate users' satisfaction with rollators. METHOD: A follow-up study was carried out in seven Danish municipalities. One month after they got their device, 89 users of rollators were interviewed by means of the QUEST 1.0. Three months after the first interview a second interview took place and data from the 64 users available for follow-up were analysed. RESULTS: The users were satisfied with their rollators, and the frequency of use was high. However, many of the users were frail, and some of them were not fully satisfied in all respects. Women especially, users living alone and first time users were likely to be dissatisfied. The main problem identified was handling the rollator, and for several users the physical environment caused accessibility problems. CONCLUSIONS: Rollators are valuable for the users and a relevant societal intervention. However, a better match between person and technology, enhanced user training and follow-up can improve the outcome of the intervention. Furthermore, better rollator design is called for, and buses and the outdoor environment need to be made more accessible.

Adult↗

PubMed2003

Transcriptome analysis of the cowpea weevil bruchid: identification of putative proteinases and alpha-amylases associated with food breakdown.

We describe here the first systematic work to discover insect genes involved in food breakdown using a cDNA library enriched for gut-expressed transcripts from Callosobruchus maculatus. A total of 1056 clones were screened for cDNA insert-containing plasmids, and 503 nonredundant open reading frames were discovered. Twenty-three inferred genes potentially involved in digestive processes in cowpea weevil were identified, including proteinases and amylases. The predicted catalytic sites were identified in the inferred cysteine and aspartic acid proteinases, and in alpha-amylases. Transcriptome analysis of the cowpea bruchid will potentially permit gene discovery in other beetles, an insect order of major economic and ecological importance that is poorly represented in genomic databases.

Amino Acid Sequence↗

PubMed2002

Search for the production of single sleptons through R-parity violation in pp; collisions at square root (s) =1.8 TeV.

We report the first search for supersymmetric particles via s-channel production and decay of smuons or muon sneutrinos at hadronic colliders. The data for the two-muon and two-jets final states were collected by the D0 experiment and correspond to an integrated luminosity of 94+/-5 pb(-1). Assuming that R parity is violated via the single coupling lambda'211, the number of candidate events is in agreement with expectation from the standard model. Exclusion contours are given in the (m(0),m(1/2)) and (m(x),m(v)) planes for lambda(')(211)=0.09, 0.08, and 0.07.

Journal Article↗

PubMed2002

Search for R-parity violating supersymmetry in two-muon and four-jet topologies.

We present results of a search for R-parity-violating decay of the neutralino chi;01, taken as the lightest supersymmetric particle, to a muon and two jets. The decay proceeds through a lepton-number violating coupling lambda(')(2jk) (j=1,2; k=1,2,3), with R-parity conservation in all other production and decay processes. In the absence of candidate events from 77.5+/-3.9 pb(-1) of data collected by the D0 experiment at the Fermilab Tevatron in pp collisions at sqrt[s]=1.8 TeV, and with an expected background of 0.18+/-0.03+/-0.02 events, we set limits on squark and gluino masses within the framework of the minimal low-energy supergravity-supersymmetry model.

Journal Article↗

PubMed2002

MEA-Tools: an open source toolbox for the analysis of multi-electrode data with MATLAB.

Recent advances in electrophysiological techniques have created new tools for the acquisition and storage of neuronal activity recorded simultaneously with numerous electrodes. These techniques support the analysis of the function as well as the structure of individual electrogenic cells in the context of surrounding neuronal or cardiac network. Commercially available tools for the analysis of such data, however, cannot be easily adapted to newly emerging requirements for data analysis and visualization, and cross compatibility between them is limited. In this report we introduce a free open source toolbox called microelectrode array tools (MEA-Tools) for the analysis of multi-electrode data based on the common data analysis environment MATLAB (version 5.3-6.1, The Mathworks, Natick, MA). The toolbox itself is platform independent. The file interface currently supports files recorded with MCRack (Multi Channel Systems, Reutlingen, Germany) under Microsoft Windows 95, 98, NT, and 2000, but can be adapted to other data acquisition systems. Functions are controlled via command line input and graphical user interfaces, and support common requirements for the analysis of local field potentials, extracellular spike activity, and continuous recordings, in addition to supplementary data acquired by additional instruments, e.g. intracellular amplifiers. Data may be processed as continuous recordings or time windows triggered to some event.

Action Potentials↗

PubMed2002

Search for leptoquark pairs decaying into nunu+jets in pp collisions at square root[s] = 1.8 TeV.

We present the results of a search for leptoquark (LQ) pairs in (85.2+/-3.7) pb(-1) of pp* collider data collected by the D0 experiment at the Fermilab Tevatron. We observe no evidence for leptoquark production and set a limit on sigma(pp*-->LQLQ-->nunu+jets) as a function of the mass of the leptoquark (m(LQ)). Assuming the decay LQ-->nuq, we exclude scalar leptoquarks for m(LQ) < 98 GeV/c(2), and vector leptoquarks for m(LQ) < 200 GeV/c(2) and coupling which produces the minimum cross section, at a 95% confidence level.

Journal Article↗

PubMed2002

Search for the scalar top quark in pp collisions at square root[s] = 1.8 TeV.

We have performed a search for scalar top quark (stop) pair production in the inclusive electron-muon-missing transverse energy final state, using a sample of pp events corresponding to 108.3 pb(-1) of data collected with the D0 detector at Fermilab. The search is done in the framework of the minimal supersymmetric standard model assuming that the sneutrino is the lightest supersymmetric particle. For the dominant decays of the lightest stop, t-->b chi+1 and t-->blnu, no evidence for signal is found. We derive cross-section limits as a function of stop ( t ), chargino ( chi+1), and sneutrino ( nu) masses.

Journal Article↗

PubMed2002

Direct search for charged higgs bosons in decays of top quarks.

We present a search for charged Higgs bosons in decays of pair-produced top quarks in pp collisions at sqrt[s] = 1.8 TeV recorded by the D0 detector at the Fermilab Tevatron collider. With no evidence for signal, we exclude most regions of the ( M(H+/-),tan(beta)) parameter space where the decay t--> H(+)b has a branching fraction >0.36 and B(H+/--->tau(nu)(tau)) is large.

Journal Article↗

PubMed2002

[Long-term outcome of AV node modulation in 387 consecutive patients with AV nodal reentrant tachycardia].

UNLABELLED: Aim of this study was to assess the long-term results of AV-node modulation in patients with AV nodal reetrant tachycardia. METHODS: From December 1991 until September 1999, AV node modulation (ablation of the fast pathway or ablation/modification of the slow pathway) was performed in 387 consecutive patients with clinically apparent AV nodal reentrant tachycardia. Follow-up data was available in 95% of patients with a mean of 41 +/- 26 months after ablation. RESULTS: Acute success rate was 97%. During long-term follow-up recurrence rate was 7.4% without any difference between fast and slow pathway ablation. Recurrence occurred in 23% of patients with persistent dual AV node physiology after ablation (modification of the slow pathway) in contrast to 3% without dual AV node physiology (ablation of the slow pathway) (p = 0.002). The presence of a dual AV node physiology after slow pathway modulation was the only predictor of recurrence during long-term follow-up. The complication rate was 5.7%. The incidence of complete heart block was 1% without any difference between fast and slow pathway ablation. CONCLUSIONS: Catheter modulation of the AV node for the treatment of AV nodal reentrant tachycardia is effective and safe. During long-term follow-up, the recurrence rate was low. Modulation of the slow pathway is associated with a significantly higher recurrence rate than ablation of the slow pathway.

Adult↗

PubMed2002

Differential expression and induction of two Drosophila cytochrome P450 genes near the Rst(2)DDT locus.

Previous studies have shown that the major metabolic resistance locus in the insecticide-resistant Drosophila line Rst(2)DDT(Wisconsin) maps between the markers cn and vg on chromosome 2. Six cytochrome P450 genes exist in this region. We investigated the expression levels of these P450 genes in DDT-resistant and -susceptible fly lines. We report: (i) DDT resistance is significant (> 30-fold) and dominant, (ii) resistance is reduced by the cytochrome P450 inhibitor PBO, (iii) there is constitutive over-expression relative to susceptible flies of two genes encoding cytochrome P450 enzymes within the cn-vg region (CYP6G1 = 4.3-fold; CYP12D1 = 6.0-fold), and (iv) exposure to DDT results in an increased expression of only one of these two P450 genes (CYP12D1 > or = 6-fold above constitutive resistant fly baselines).

Animals↗

PubMed2001

Ratio of isolated photon cross sections in pp macro collisions at square root of s = 630 and 1800 GeV.

The inclusive cross section for production of isolated photons has been measured in pp macro collisions at square root of s = 630 GeV with the D0 detector at the Fermilab Tevatron Collider. The photons span a transverse energy (E(T)) range from 7-49 GeV and have pseudorapidity absolute value of eta < 2.5. This measurement is combined with the previous D0 result at square root of s = 1800 GeV to form a ratio of the cross sections. Comparison of next-to-leading-order QCD with the measured cross section at 630 GeV and the ratio of cross sections show satisfactory agreement in most of the E(T) range.

Journal Article↗

PubMed2001

Search for new physics using QUAERO: a general interface to D0 event data.

We describe QUAERO, a method that (i) enables the automatic optimization of searches for physics beyond the standard model, and (ii) provides a mechanism for making high energy collider data generally available. We apply QUAERO to searches for standard model WW, ZZ, and t t macro production, to searches for these objects produced through a new heavy resonance, and to the first direct search for W'-->WZ. Through this interface, we make three data sets collected by the D0 experiment at square root of [s] = 1.8 TeV publicly available.

Journal Article↗

PubMed2001

Search for heavy particles decaying into electron-positron pairs in pp collisions.

We present results of searches for technirho (rho(T)), techniomega (omega(T)), and Z' particles, using the decay channels rho(T),omega(T),Z'-->e(+)e(-). The search is based on 124.8 pb(-1) of data collected by the D0 detector at the Fermilab Tevatron during 1992-1996. In the absence of a signal, we set 95% C.L. upper limits on the cross sections for the processes pp-->rho(T),omega(T),Z'-->e(+)e(-) as a function of the mass of the decaying particle. For certain model parameters, we exclude the existence of degenerate rho(T) and omega(T) states with masses below about 200 GeV. We exclude a Z' with mass below 670 GeV, assuming that it has the same couplings to fermions as the Z boson.

Journal Article↗

PubMed2001

Economic and clinical impact of alternative disease management strategies for secondary prevention in type 2 diabetes in the Swiss setting.

PRINCIPLES: Different intervention strategies for the optimisation of disease management of diabetes exist and have been shown to increase the proportion of patients receiving screening and examinations and to improve risk factors such as HbA1c, lipids, and blood pressure. Thus, in the long-term, a decrease in diabetic complications and the associated costs could be expected. To address this question, the current analysis used a published diabetes simulation model to analyse the long-term clinical and economic implications of implementing various interventions in the Swiss setting. METHODS: Based on data from the literature, the short-term effects on clinical variables of multifactorial interventions, including screening for nephropathy and retinopathy, educational programmes and control of cardiovascular risk profile were assessed, and a cost-effectiveness analysis in comparison to standard care was performed. Life expectancy (LE) and total lifetime costs (TC) from the perspective of the health insurance payer were calculated using a long-term Markov simulation model. RESULTS: The multifactorial intervention led to an improvement in undiscounted LE of 0.56 years (LE = 10.73 and 11.29 years for standard care and multifactorial intervention respectively), and a reduction in 3%-discounted TC of CHF 7313 (10.7%) per patient compared to current standard practice. Extrapolation to the whole Swiss type 2 diabetes population (285,000) showed yearly cost savings of CHF 194 million from the multifactorial intervention. CONCLUSIONS: The implementation of multifactorial interventions, including improved control of cardiovascular risk factors, combined with early diagnosis and treatment of diabetic complications, could be both cost- and life-saving in the Swiss setting.

Complementary Therapies↗

PubMed2001

High-performance liquid chromatography--ToxPrint: chromatographic analysis with a novel (geno)toxicity detection.

In order to aid the monitoring of the overall quality of (surface) waters a new analytical approach has been developed, combining on-line solid-phase extraction, HPLC separation and effect-related detection. Compounds present in surface water or wastewater samples are extracted on-line with Oasis [poly(divinylbenzene-co-N-vinylpyrrolidone)] material and directly fractionated by reversed-phase HPLC. The eluent of the total chromatogram is collected on a microtitre plate in fractions of 1 min each. After evaporation and re-dissolvation in a suitable solvent, the (geno)toxicity of the individual fractions before and after enzymatic activation with S9, is determined with the umu test. In this way, harmful compounds can be detected and localized in the HPLC-diode array detection trace even without their identity and exact concentration being known at that moment. The method was developed using two test compounds, 4-nitroquinoline-N-oxide and 2-aminoanthracene. Compounds with mutagenic properties comparable to those of the test compounds can be detected from 0.1 microg/l, which is a concentration relevant for surface waters. The new analytical approach was successfully applied to various types of model samples, as well as real wastewater.

4-Nitroquinoline-1-oxide↗

PubMed2001

Quasi-model-independent search for new high p(T) physics at D0.

We apply a quasi-model-independent strategy ("Sleuth") to search for new high p(T) physics in approximately 100 pb(-1) of pp collisions at square root of (s) = 1.8 TeV collected by the D0 experiment during 1992-1996 at the Fermilab Tevatron. We systematically analyze many exclusive final states and demonstrate sensitivity to a variety of models predicting new phenomena at the electroweak scale. No evidence of new high p(T) physics is observed.

Journal Article↗

PubMed2001

Ratio of jet cross sections at square root of s = 630 GeV and 1800 GeV.

The D0 Collaboration has measured the inclusive jet cross section in barpp collisions at square root of s = 630 GeV. The results for pseudorapidities (eta)<0.5 are combined with our previous results at square root of s = 1800 GeV to form a ratio of cross sections with smaller uncertainties than either individual measurement. Next-to-leading-order QCD predictions show excellent agreement with the measurement at 630 GeV; agreement is also satisfactory for the ratio. Specifically, despite a 10% to 15% difference in the absolute magnitude, the dependence of the ratio on jet transverse momentum is very similar for data and theory.

Journal Article↗