Search results for "Names"
showing 10 items of 6843 documents
Localization of segmental arteries in renal surgery by Doppler sonography.
1982
Abstract To avoid damage to major arteries of the renal parenchyma during nephrotomy, intraoperative Doppler sonography was used experimentally and clinically as an artery finder. In experiments with 7 beagles segmental arteries were detected easily and reliably by sonography, and the arterial course thus indicated correlated perfectly with arteriograms and casts. In a clinical trial the Doppler artery finder was used in 7 patients with staghorn calculi that were removed via the renal pelvis and additional multiple selective nephrotomies. With as many as 7 selective nephrotomies in a single kidney there was no damage to the major arteries in any of these patients. Selective, avascular nephr…
Dynamic MR imaging of breast lesions: correlation with microvessel distribution pattern and histologic characteristics of prognosis.
2006
To evaluate the association of dynamic enhancement parameters of benign and malignant breast lesions at magnetic resonance (MR) imaging with microvessel distribution and histologic prognostic tumor characteristics.Regional review board approval and informed consent were obtained. Surgical resection specimens of breast lesions (32 benign, 86 malignant) in 118 patients (age range, 28-86 years; mean, 58 years) who had undergone dynamic T1-weighted MR imaging of both breasts were included in the study. Different MR enhancement parameters and microvessel density (MVD) distribution were determined. In malignant lesions, TNM stage, tumor grade, proliferative activity, and hormone receptor expressi…
Blood flow velocity waveforms of the fetal middle cerebral artery in a normal population: reference values from 18 weeks to 42 weeks of gestation
2002
The aim of this prospective cross-sectional study was to establish new Doppler reference curves for peak blood flow velocities (Vmax, Vmean, Vmin) and impedance indices (PI, RI) of the middle cerebral artery at 18-42 weeks of gestation by an automatic wave form analysis integrated into the ultrasound device. In 962 low-risk pregnancies, blood flow velocities were derived from the middle cerebral artery with pulsed color Doppler ultrasonography. Reference curves were constructed for the individual parameters based on a growth function from a four-parameter class of monotonic continuous functions according to the smallest square principle for maximum blood flow velocities, as well as on a pol…
Surrogate data approaches to assess the significance of directed coherence: Application to EEG activity propagation
2009
This paper addresses the topic of evaluating the significance of frequency domain measures of causal coupling in multivariate time series through generation of surrogate data. The considered approaches are the traditional Fourier Transform (FT) algorithm and a new causal FT (CFT) algorithm for surrogate data generation. Both algorithms preserve the FT modulus of the original series; differences are in the phase relationships, that are completely destroyed for FT surrogates and imposed after switching off the link over the considered causal direction for CFT surrogates. The ability of the algorithms to assess causality in the frequency domain was tested using the directed coherence as discri…
Testing Frequency-Domain Causality in Multivariate Time Series
2010
We introduce a new hypothesis-testing framework, based on surrogate data generation, to assess in the frequency domain, the concept of causality among multivariate (MV) time series. The approach extends the traditional Fourier transform (FT) method for generating surrogate data in a MV process and adapts it to the specific issue of causality. It generates causal FT (CFT) surrogates with FT modulus taken from the original series, and FT phase taken from a set of series with causal interactions set to zero over the direction of interest and preserved over all other directions. Two different zero-setting procedures, acting on the parameters of a MV autoregressive (MVAR) model fitted on the ori…
Oral status and Candida colonization in patients with Sjogren s Syndrome
2009
Objective: To determine the oral status, salivary flow rate, Candida carriage in saliva, and prevalence of Candida albicans colonization in several areas of the mouth in patients with primary and secondary Sjögren?s syndrome as opposed to those of healthy subjects. Study design: Thirty-seven patients with Sjögren?s syndrome (SS), [14 patients with primary SS (SS-1) and 23 patients with secondary SS (SS-2)], along with 37 healthy controls were examined in regard to number of teeth, pro-bing pocket depth (PPD), approximal plaque index (API), bleeding on probing (BOP), presence of prosthetic appliances and smoking habits. Salivary flow rate (SFR), Candida carriage in saliva, presence of Candid…
Phase information of time-frequency transforms as a key feature for classification of atrial fibrillation episodes
2015
[EN] Patients suffering from atrial fibrillation can be classified into different subtypes, according to the temporal pattern of the arrhythmia and its recurrence. Nowadays, clinicians cannot differentiate a priori between the different subtypes, and patient classification is done afterwards, when its clinical course is available. In this paper we present a comparison of classification performances when differentiating paroxysmal and persistent atrial fibrillation episodes by means of support vector machines. We analyze short surface electrocardiogram recordings by extracting modulus and phase features from several time-frequency transforms: short-time Fourier transform, Wigner-Ville, Choi-…
Doppler and B-mode ultrasound for avascular nephrotomy.
1983
AbstractDoppler sonography for intraoperative localization of the intrarenal arteries combined with B-scan sonography for intraoperative visualization of stones allows complete stone removal via small radial nephrotomies for which clamping of the renal artery is no longer necessary. Since September 1980 we used this technique on 35 patients with staghorn or recurrent calculi. The main advantages of this technique are exact and quick stone localization, minimal loss of renal function owing to preservation of the intrarenal vascular system, and no need for renal ischemia and cooling.
Numerical approach to problems of gravitational instability of geostructures with advected material boundaries
1998
SUMMARY We present a numerical approach for solving 2-D mantle flow problems where the chemical composition changes abruptly across intermediate boundaries. The method combines a Galerkin-spline technique with a method of integration over regions bounded by advected interfaces to represent discontinuous variations of material parameters. It allows direct approximation of a natural free surface position, instead of a posteriori calculation of topography from the normal stress at the upper free-slip boundary. We formulate a model where a viscous incompressible fluid filling a square box is divided into layers (not necessarily horizontal) by advected boundaries, across which the density and vi…
Thermodynamic Behavior of Non-Ionic Tri-block Copolymers in Water at Three Temperatures
2006
Apparent molar volumes (V Φ) of aqueous solutions of some copolymers, based on ethylene oxide (EO) and propylene oxide (PO) units, were determined as functions of concentration at three temperatures. Viscosity measurements were also carried out on some of these systems. The effects studied include how the molecular architecture and the molecular weight affect the aggregation of the copolymer, keeping constant the EO/PO ratio. Modeling of the volumetric data yielded the partial molar volume of the copolymer in the standard (V°) and the aggregated (V M) states, as well as the equilibrium constant for micellization and the aggregation number. Analysis of the viscosity data supported the insigh…