An Approach to Overcoming Specific Difficulties with Cardiac Resynchronization Therapy in Children

Cardiac resynchronization therapy (CRT) is now a well established treatment modality for adult patients with drug refractory symptomatic congestive heart failure. Multiple large-scale studies have clearly demonstrated reduction in heart failure-related morbidity with CRT. More recently, a likely independent mortality benefit with CRT has also been shown. Improvement in quality of life, decrease in left ventricular diastolic dimension, improved objective assessment of exercise tolerance, and decreased heart failure-related hospitalizations have all been well demonstrated in the adult population. Whether or not these benefits occur in younger patients is not clear. Since none of the major trials for CRT have included children, much is unknown about the specifics of indication, difficulties with implant, and efficacy in the pediatric populatio

Putting hydrodynamic interactions to work: tagged particle separation

Separation of magnetically tagged cells is performed by attaching markers to a subset of cells in suspension and applying fields to pull from them in a variety of ways. The magnetic force is proportional to the field gradient, and the hydrodynamic interactions play only a passive, adverse role. Here we propose using a homogeneous rotating magnetic field only to make tagged particles rotate, and then performing the actual separation by means of hydrodynamic interactions, which thus play an active role. The method, which we explore here theoretically and by means of numerical simulations, lends itself naturally to sorting on large scales.Comment: Version accepted for publication - Europhysics Letter

Phase unwrapping : geometric distortions correction on MRI

Magnetic Resonance Imaging has entered clinical practice about fifteen years ago, and has become one of the most widely used imaging modality. MRI suffers from important geometric distortions, leading to pixel shifts and intensity variations in the acquired images. Correction of these distortions is clearly required in stereotactic surgery using frame-based registrations or neuro-navigation. These distortions can be corrected using the phase of signal or image. However, as in Inverse Synthetic Aperture Radar (ISAR), the phase of the signal is obtained modulo 2 π. The goal of Phase unwrapping is to retrieve the initial phase of the signal. After a brief summary of related works and applications mainly using ISAR data, this paper presents a new algorithm for phase unwrapping. This algorithm is fast, robust to noise and takes into account the discontinuities of the acquired object. It is based upon the notion of homogeneous region. This homogeneity is defined by phase jumps and no parameters have to be determined a priori. Experiments on noisy phantoms exhibit good robustness to noise. An application to the correction of MRI of the head is presented.Les images du corps humain acquises par résonance magnétique sont une des modalités les plus utilisées à des fins cliniques depuis une quinzaine d'années. Elles souffrent cependant de distorsions géométriques importantes sous forme de décalages de pixels et de variations d'intensité. Ces distorsions doivent être corrigées pour utiliser ces imagés dans des applications de neuro-navigation ou de neuro-chirurgie stéréotaxiques. Une des solutions pour la correction exploite les images de phase issues de l'imageur. Cependant, comme en Interférométrie Radar à Ouverture Synthétique (ISAR), cette phase est codée modulo 2 π. Le déroulement de phase a pour objectif de retrouver la phase réelle du signal. Après un rapide bilan des outils existants, principalement dans le domaine ISAR, nous proposons dans cet article un algorithme de déroulement de phase original, rapide, robuste au bruit et qui prend en compte les discontinuités réelles de l'objet imagé. Il est basé sur la notion de région homogène du point de vue des sauts de phase et ne nécessite pas la détermination de paramètres. Les tests sur des fantômes bruités démontrent la bonne robustesse au bruit. Cet algorithme est ensuite utilisé pour la correction d'images IRM et illustre le bon déroulement de la phase

The perseveration of checking thoughts and mood–as–input hypothesis

This paper describes two experiments designed to investigate how a current model of task perseveration, the mood-as-input hypothesis, might be applied to activities relevant to compulsive checking. The mood-as-input hypothesis predicts that perseveration at an open-ended task will be determined by a combination of the “stop rules” adopted for the task, and the valency of the mood state in which the task is conducted. Experiment 1 required participants to generate items that should be checked for safety/security if they were leaving their home unattended. Experiment 2 used an analogue recall task, in which participants were asked to recall items from a comprehensive list of items that should be checked if they were to leave their home safe/secure. Both experiments found that perseveration at the tasks was determined by particular configurations of mood and stop rules for the task. Of most relevance to compulsive checking was the fact that facilitated perseveration occurred when participants were asked to undertake the tasks in a negative mood using “as many as can” stop rules. Implications for the factors that develop and maintain compulsive checking are discussed

The dependence of the anomalous J/psi suppression on the number of participant nucleons

The observation of an anomalous J/psi suppression in Pb-Pb collisions by the NA50 Collaboration can be considered as the most striking indication for the deconfinement of quarks and gluons at SPS energies. In this Letter, we determine the J/psi suppression pattern as a function of the forward hadronic energy E-ZDC measured in a Zero Degree Calorimeter (ZDC). The direct connection between EZDC and the geometry of the collision allows us to calculate, within a Glauber approach, the precise relation between the number of participant nucleons N-part and E-ZDC. Then, we check if the experimental data can be better explained by a sudden or a smooth onset of the anomalous J/psi suppression as a function of the number of participants. (C) 2001 Elsevier Science B.V. All rights reserved.info:eu-repo/semantics/publishedVersio

Evaluation of machine-learning methods for ligand-based virtual screening

Machine-learning methods can be used for virtual screening by analysing the structural characteristics of molecules of known (in)activity, and we here discuss the use of kernel discrimination and naive Bayesian classifier (NBC) methods for this purpose. We report a kernel method that allows the processing of molecules represented by binary, integer and real-valued descriptors, and show that it is little different in screening performance from a previously described kernel that had been developed specifically for the analysis of binary fingerprint representations of molecular structure. We then evaluate the performance of an NBC when the training-set contains only a very few active molecules. In such cases, a simpler approach based on group fusion would appear to provide superior screening performance, especially when structurally heterogeneous datasets are to be processed

Study protocol of the TIRED study:A randomised controlled trial comparing either graded exercise therapy for severe fatigue or cognitive behaviour therapy with usual care in patients with incurable cancer

Background: Fatigue is a common and debilitating symptom for patients with incurable cancer receiving systemic treatment with palliative intent. There is evidence that non-pharmacological interventions such as graded exercise therapy (GET) or cognitive behaviour therapy (CBT) reduce cancer-related fatigue in disease-free cancer patients and in patients receiving treatment with curative intent. These interventions may also result in a reduction of fatigue in patients receiving treatment with palliative intent, by improving physical fitness (GET) or changing fatigue-related cognitions and behaviour (CBT). The primary aim of our study is to assess the efficacy of GET or CBT compared to usual care (UC) in reducing fatigue in patients with incurable cancer. Methods: The TIRED study is a multicentre three-armed randomised controlled trial (RCT) for incurable cancer patients receiving systemic treatment with palliative intent. Participants will be randomised to GET, CBT, or UC. In addition to UC, the GET group will participate in a 12-week supervised exercise programme. The CBT group will receive a 12-week CBT intervention in addition to UC. Primary and secondary outcome measures will be assessed at baseline, post-intervention (14 weeks), and at follow-up assessments (18 and 26 weeks post-randomisation). The primary outcome measure is fatigue severity (Checklist Individual Strength subscale fatigue severity). Secondary outcome measures are fatigue (EORTC-QLQ-C30 subscale fatigue), functional impairments (Sickness Impact Profile total score, EORTC-QLQ-C30 subscale emotional functioning, subscale physical functioning) and quality of life (EORTC-QLQ-C30 subscale QoL). Outcomes at 14 weeks (primary endpoint) of either treatment arm will be compared to those of UC participants. In addition, outcomes at 18 and 26 weeks (follow-up assessments) of either treatment arm will be compared to those of UC participants. Discussion: To our knowledge, the TIRED study is the first RCT investigating the efficacy of GET and CBT on reducing fatigue during treatment with palliative intent in incurable cancer patients. The results of this study will provide information about the possibility and efficacy of GET and CBT for severely fatigued incurable cancer patients

Centrality Behaviour of J/ψ\psi Production in Na50

The J/$\psi$ production in 158 A GeV Pb-Pb interactions is studied, in the dimuon decay channel, as a function of centrality, as measured with the electromagnetic or with the very forward calorimeters. After a first sharp variation at mid centrality, both patterns continue to fall down and exhibit a curvature change at high centrality values. This trend excludes any conventional hadronic model and is in agreement with a deconfined quark-gluon phase scenario. We report also preliminary results on the measured charged multiplicity, as given by a dedicated detector.Comment: 5 pages, 7 figures (in eps) talk given at XXXI International Symposium on Multiparticle Dynamics, Sep. 1-7, 2001, Datong China URL http://ismd31.ccnu.edu.cn

Urgent need to clarify the definition of chronic critical limb ischemia - a position paper from the European Society for Vascular Medicine

Chronic critical lower limb ischemia (CLI) has been defined as ischemia that endangers the leg. An attempt was made to give a precise definition of CLI, based on clinical and hemodynamic data (Second European Consensus). CLI may be easily defined from a clinical point of view as rest pain of the distal foot or gangrene or ulceration. It is probably useful to add leg ulcers of other origin which do not heal because of severe ischemia, and to consider the impact of frailty on adverse outcome. From a hemodynamic viewpoint there is no consensus and most of the existing classifications are not based upon evidence. We should thus propose a definition and then validate it in a prospective cohort in order to define the patients at major risk of amputation, and also to define the categories of patients whose prognosis is improved by revascularisation. From today\u27s available data, it seems clear that the patients with a systolic toe pressure (STP) below 30 mmHg must be revascularised whenever possible. However other patients with clinically suspected CLI and STP above 30 mmHg must be evaluated and treated in specialised vascular units and revascularisation has to be discussed on a case by case basis, taking into account other data such as the WiFi classification for ulcers.In conclusion, many useful but at times contradictory definitions of CLI have been suggested. Only a few have taken into account evidence, and none have been validated prospectively. This paper aims to address this and to give notice that a CLI registry within Europe will be set up to prospectively validate, or not, the previous and suggested definitions of CLI