3,673 research outputs found
Elevated levels of procoagulant microparticles in a patient with myocardial infarction, antiphospholipid antibodies and multifocal cardiac thrombosis
Circulating procoagulant microparticles (MP) are pathogenic markers of enhanced coagulability associated to a variety of disorders and released from stimulated vascular cells. When derived from endothelial cells, MP were found characteristic of thrombotic propensity in primary antiphospholipid syndrome (APS). The prothrombotic status of a patient with antiphospholipid antibodies (APL), a past history of mesenteric vein thrombosis and presenting myocardial infarction and extensive intracardiac thrombosis was examined by measurement of circulating procoagulant MP. MP of platelet and endothelial origins were highly elevated with respect to values detectable in patients with myocardial infarction and no history of APS (6- and 3-fold elevation, respectively) or in healthy volunteers (13- and 25-fold elevation, respectively). In this particular patient, with moderate APL titer, a drastic release of procoagulant MP could have contributed to thrombus growth and the development of extensive intracardiac thrombosis
Lattice QCD with mixed actions
We discuss some of the implications of simulating QCD when the action used
for the sea quarks is different from that used for the valence quarks. We
present exploratory results for the hadron mass spectrum and pseudoscalar meson
decay constants using improved staggered sea quarks and HYP-smeared overlap
valence quarks. We propose a method for matching the valence quark mass to the
sea quark mass and demonstrate it on UKQCD clover data in the simpler case
where the sea and valence actions are the same.Comment: 15 pages, 10 figures some minor modification to text and figures.
Accepted for publicatio
Phase and amplitude evolution in the network of triadic interactions of the Hasegawa-Wakatani system
The Hasegawa-Wakatani system, commonly used as a toy model of dissipative drift waves in fusion devices, is revisited with considerations of phase and amplitude dynamics of its triadic interactions. It is observed that a single resonant triad can saturate via three way phase locking, where the phase differences between dominant modes converge to constant values as individual phases increase in time. This allows the system to have approximately constant amplitude solutions. Non-resonant triads show similar behavior only when one of its legs is a zonal wave number. However, when an additional triad, which is a reflection of the original one with respect to the y axis is included, the behavior of the resulting triad pair is shown to be more complex. In particular, it is found that triads involving small radial wave numbers (large scale zonal flows) end up transferring their energy to the subdominant mode which keeps growing exponentially, while those involving larger radial wave numbers (small scale zonal flows) tend to find steady chaotic or limit cycle states (or decay to zero). In order to study the dynamics in a connected network of triads, a network formulation is considered, including a pump mode, and a number of zonal and non-zonal subdominant modes as a dynamical system. It was observed that the zonal modes become clearly dominant only when a large number of triads are connected. When the zonal flow becomes dominant as a "collective mean field,"individual interactions between modes become less important, which is consistent with the inhomogeneous wave-kinetic picture. Finally, the results of direct numerical simulation are discussed for the same parameters, and various forms of the order parameter are computed. It is observed that nonlinear phase dynamics results in a flattening of the large scale phase velocity as a function of scale in direct numerical simulations
False-positive iodine-131 whole-body scan findings in patients with differentiated thyroid carcinoma: report of 11 cases and review of the literature
BACKGROUND: Iodine-131 (I-131) whole-body scan (WBS) plays an important role in the management of patients with differentiated thyroid carcinoma (DTC), to detect normal thyroid remnants and recurrent or metastatic disease. A focus of I-131 accumulation outside the thyroid bed and the areas of physiological uptake is strongly suggestive of a distant functioning metastasis. However, many false-positive I-131 WBS findings have been reported in the literature.
PATIENT FINDINGS: We describe a series of 11 personal cases of patients with DTC, collected from 1992 to 2011, in whom diagnostic or post-treatment WBS showed false-positive retention of I-131 in various locations.
SUMMARY: False-positive accumulations of I-131 on WBS may be classified according to the underlying pathophysiological mechanisms: external and internal contaminations by body secretions, ectopic normal thyroid and gastric tissues, inflammatory and infectious diseases, benign and malignant tumors, cysts and effusions of serous cavities, thymic uptake, and other non classified causes.
CONCLUSIONS: Clinicians must be aware of possible false-positive findings to avoid misinterpretations of the I-131 WBS, which could lead to inappropriate treatments
Individual Fluorouracil Dose Adjustment in FOLFOX Based on Pharmacokinetic Follow-Up Compared With Conventional Body-Area-Surface Dosing: A Phase II, Proof-of-Concept Study
BackgroundTo compare the efficacy and safety of pharmacokinetically (PK) guided fluorouracil (5-FU) dose adjustment vs. standard body-surface-area (BSA) dosing in a FOLFOX (folinic acid, fluorouracil, oxaliplatin) regimen in metastatic colorectal cancer (mCRC). Patients And Methods A total of 118 patients with mCRC were administered individually determined PK-adjusted 5-FU in first-line FOLFOX chemotherapy. The comparison arm consisted of 39 patients, and these patients were also treated with FOLFOX with 5-FU by BSA. For the PK-adjusted arm 5-FU was monitored during infusion, and the dose for the next cycle was based on a dose-adjustment chart to achieve a therapeutic area under curve range (5-FUODPM Protocol). Results The objective response rate was 69.7% in the PK-adjusted arm, and median overall survival and median progression-free survival were 28 and 16 months, respectively. In the traditional patients who received BSA dosage, objective response rate was 46%, and overall survival and progression-free survival were 22 and 10 months, respectively. Grade 3/4 toxicity was 1.7% for diarrhea, 0.8% for mucositis, and 18% for neutropenia in the dose-monitored group; they were 12%, 15%, and 25%, respectively, in the BSA group. Conclusions Efficacy and tolerability of PK-adjusted FOLFOX dosing was much higher than traditional BSA dosing in agreement with previous reports for 5-FU monotherapy PK-adjusted dosing. Analysis of these results suggests that PK-guided 5-FU therapy offers added value to combination therapy for mCRC
VLTI/MIDI observations of 7 classical Be stars
We measured the mid-infrared extension of the gaseous disk surrounding seven
Be stars in order to constrain the geometry of their circumstellar environments
and to try to infer physical parameters characterizing these disks. We used the
VLTI/MIDI instrument with baselines up to 130 m to obtain an angular resolution
of about 15 mas in the N band and compared our results with previous K band
measurements obtained with the VLTI/AMBER instrument and/or the CHARA
interferometer. We obtained one calibrated visibility measurement for each of
the four stars, p Car, zeta Tau, kappa CMa, and alpha Col, two for delta Cen
and beta CMi, and three for alpha Ara. Almost all targets remain unresolved
even with the largest VLTI baseline of 130m, evidence that their circumstellar
disk extension is less than 10 mas. The only exception is alpha Ara, which is
clearly resolved and well-fitted by an elliptical envelope with a major axis
a=5.8+-0.8mas and an axis ratio a/b=2.4+-1 at 8 microns. This extension is
similar to the size and flattening measured with the VLTI/AMBER instrument in
the K band at 2 microns. The size of the circumstellar envelopes for these
classical Be stars does not seem to vary strongly on the observed wavelength
between 8 and 12microns. Moreover, the size and shape of Alpha Ara's disk is
almost identical at 2, 8, and 12microns
Point-of-Care Diagnostics for Infection and Antimicrobial Resistance in Sub-Saharan Africa - A Narrative Review.
INTRODUCTION
Sub-Saharan African (SSA) countries are severely impacted by antimicrobial resistance (AMR). Due to gaps in access to diagnostics in SSA the true extent of AMR remains unknown. This diagnostic gap affects patient management and leads to significant antimicrobial overuse. This review explores how point-of-care (POC) testing for pathogen identification and AMR may be used to close the diagnostic gap in SSA countries.
METHODS
A narrative review exploring current clinical practice and novel developments in the field of point-of-care (POC) testing for infectious diseases and AMR.
FINDINGS
POC assays for identification of various pathogens have been successfully rolled out in SSA countries. While implementation studies have mostly highlighted impressive test performance of POC assays, there is limited data on effect of implementation on clinical outcomes and cost-effectiveness. We did not encounter local studies of host-directed POC assays relevant to AMR. Novel POC assays using real-time PCR, isothermal amplification, microfluidics and other technologies are in various stages of development.
DISCUSSION
Available literature shows that POC testing for AMR applications is implementable in SSA and holds the potential to reduce the diagnostic gap. Implementation will require effective regulatory pathways, incorporation of POC testing in clinical and laboratory guidelines, and adequate value capture in existing health financing models
Robotic exoskeletons: A perspective for the rehabilitation of arm coordination in stroke patients
Upper-limb impairment after stroke is caused by weakness, loss of individual joint control, spasticity, and abnormal synergies. Upper-limb movement frequently involves abnormal, stereotyped, and fixed synergies, likely related to the increased use of sub-cortical networks following the stroke. The flexible coordination of the shoulder and elbow joints is also disrupted. New methods for motor learning, based on the stimulation of activity- dependent neural plasticity have been developed. These include robots that can adaptively assist active movements and generate many movement repetitions. However, most of these robots only control the movement of the hand in space. The aim of the present text is to analyze the potential of robotic exoskeletons to specifically rehabilitate joint motion and particularly inter-joint coordination. First, a review of studies on upper-limb coordination in stroke patients is presented and the potential for recovery of coordination is examined. Second, issues relating to the mechanical design of exoskeletons and the transmission of constraints between the robotic and human limbs are discussed. The third section considers the development of different methods to control exoskeletons: existing rehabilitation devices and approaches to the control and rehabilitation of joint coordinations are then reviewed, along with preliminary clinical results available. Finally, perspectives and future strategies for the design of control mechanisms for rehabilitation exoskeletons are discussed
Structural and superconducting transition in selenium under high pressures
First-principles calculations are performed for electronic structures of two
high pressure phases of solid selenium, -Po and bcc.
Our calculation reproduces well the pressure-induced phase transition from
-Po to bcc observed in selenium.
The calculated transition pressure is 30 GPa lower than the observed one, but
the calculated pressure dependence of the lattice parameters agrees fairly well
with the observations in a wide range of pressure.
We estimate the superconducting transition temperature of both
the -Po and the bcc phases by calculating the phonon dispersion and the
electron-phonon interaction on the basis of density-functional perturbation
theory.
The calculated shows a characteristic pressure dependence, i.e.
it is rather pressure independent in the -Po phase, shows a
discontinuous jump at the transition from -Po to bcc, and then decreases
rapidly with increasing pressure in the bcc phase.Comment: 8 pages, 11 figure
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