Search results for "ABLATION"
showing 10 items of 322 documents
Forensic investigation of brick stones using instrumental neutron activation analysis (INAA), laser ablation-inductively coupled plasma-mass spectrom…
2009
Abstract Brick stones collected from different production facilities were studied for their elemental compositions under forensic aspects using laser ablation–inductively coupled plasma–mass spectrometry (LA–ICP–MS), instrumental neutron activation analysis (INAA) and X-ray fluorescence analysis (XRF). The aim of these examinations was to assess the potential of these methods in forensic comparison analyses of brick stones. The accuracy of the analysis methods was evaluated using NIST standard reference materials (679, 98b and 97b). In order to compare the stones to each other, multivariate data analysis was used. The evaluation of the INAA results (based on the concentrations of V, Na, K, …
Direct determination of halogens in powdered geological and environmental samples using isotope dilution laser ablation ICP-MS
2005
Abstract Laser ablation inductively coupled plasma isotope dilution mass spectrometry (LA-ICP-IDMS) with a special laser ablation system for bulk analyses (LINA-Spark™-Atomiser) was applied for direct determinations of chlorine, bromine, and iodine in rock and sediment samples. Special attention was focused on possible inter-halogen fractionations and analyte/spike isotope fractionations by using LA-ICP-MS and LA-ICP-IDMS, respectively. A variation of Br/Cl and I/Cl element intensity ratios by a factor of 1.3–3 was observed when changing the nebulizer gas flow rate in the range of 0.84–1.0 L min−1 and the laser power density in the range of 2–10 GW cm−2, respectively. When using an internal…
“Three-level shock” in ablation-refractory paroxysmal atrial fibrillation
1987
His-bundle ablation is a very effective method to control drug-refractory supraventricular arrhythmias. We present a 69-year-old woman with paroxysmal atrial fibrillation, in whom several attempts of unipolar and bipolar His-bundle ablation were ineffective. Ultimately a stable 2/1 atrioventricular block was induced when three successive shocks of 400 W were applied. The first shock was given in that position with the largest His-potential deflection. The other two shocks were applied at catheter positions more distal and more proximal from the first one, respectively. We suppose that the initial lack of success was due to an atypical atrioventricular junction anatomy.
REsect: Blinded assessment of amenability to potentially curative treatment of previously unresectable colorectal cancer liver metastases (CRC LM) af…
2017
3532 Background: Secondary resection and radiofrequency ablation (RFA) of primarily unresectable LM from CRC can prolong survival and cure some patients (pts). Effective downsizing treatments are needed but their impact on secondary amenability to surgery/RFA is difficult to evaluate objectively. The added value of SIRT is not well established. Methods: Baseline (BL) and follow-up (FU) imaging at best response for CRC pts treated with FOLFOX chemotherapy±bevacizumab (bev) (CT) vs. CT+SIRT in the phase III SIRFLOX RCT were reviewed by 3−5 expert HPB surgeons (from a panel of 15) for resectability of LM. Reviewers were blinded to each other and to all clinical information incl. time of imagi…
Refining Prognosis in Chemoembolization for Hepatocellular Carcinoma: Immunonutrition and Liver Function
2021
A combination of albumin-bilirubin (ALBI) grading and the Prognostic Nutritional Index (PNI) was identified recently as a highly predictive tool for patients with hepatocellular carcinoma (HCC) undergoing tumor ablation. The present study evaluated this combination in patients undergoing transarterial chemoembolization (TACE). Between 2010 and 2020, 280 treatment-naïve patients were retrospectively identified. The influence of ALBI grade, PNI and the novel ALBI-PNI on the median overall survival (OS) was assessed. In the next step, the prognostic ability of the combined approach was compared to established scoring systems. Both ALBI grade 2−3 and a low PNI were highly predictive for median …
Electrocardiographic Imaging for Atrial Fibrillation: A Perspective From Computer Models and Animal Experiments to Clinical Value
2021
[EN] Electrocardiographic imaging (ECGI) is a technique to reconstruct non-invasively the electrical activity on the heart surface from body-surface potential recordings and geometric information of the torso and the heart. ECGI has shown scientific and clinical value when used to characterize and treat both atrial and ventricular arrhythmias. Regarding atrial fibrillation (AF), the characterization of the electrical propagation and the underlying substrate favoring AF is inherently more challenging than for ventricular arrhythmias, due to the progressive and heterogeneous nature of the disease and its manifestation, the small volume and wall thickness of the atria, and the relatively large…
Alcohol-Mediated Renal Sympathetic Neurolysis for the Treatment of Hypertension: The Peregrine™ Infusion Catheter.
2020
Renal sympathetic denervation using conventional non-irrigated radiofrequency catheters has potential technical shortcomings, including limited penetration depth and incomplete circumferential nerve damage, potentially impacting therapeutic efficacy. Against this background, second generation multi-electrode, radiofrequency and ultrasound renal denervation systems have been developed to provide more consistent circumferential nerve ablation. Irrigated catheters may allow deeper penetration while minimizing arterial injury. In this context, catheter-based chemical denervation, with selective infusion of alcohol, a potent neurolytic agent, into the perivascular space, may minimize endothelial…
Analyse et détection des électrogrammes complexes fractionnés en vue de soigner la fibrillation auriculaire à l'aide de techniques d'ablation par rad…
2013
This manuscript presents research on the analysis and the detection of Complex Fractionated Atrial Electrograms (CFAE). In the first part, following a presentation over Atrial Fibrillation (AF) mechanisms and bioelectrical signals, the most commonly used tools for analyzing CFAE are presented. Linear tools are initially applied to signals from AF ablation procedures, then nonlinear tools are shown and integrated intoa CFAE detection algorithm. This one is based on the quantification of electrogram recurrence properties. In the second part, the cell and cardiac muscle tissue are described and simulated using mathematical models. Models such as FitzHugh Nagumo, Aliev Panfilov and Courtemanche…
Experimental and quantum-chemical characterization of heavy carbon subchalcogenides: Infrared detection of SeC3Se
2021
Abstract High-resolution infrared studies of laser ablation products from carbon-selenium targets have revealed a new vibrational band at 2057 cm−1 that is identified as the ν 3 vibrational fundamental of the SeC3Se cluster. Because of the rich isotopic composition of selenium and the heavy nuclear masses involved, the vibrational band shows a relatively compact and complex structure despite the simple linear geometric arrangement. Overall, rotational-vibrational lines of six isotopologues could be assigned and fitted permitting the derivation of an accurate selenium-carbon bond length. Spectroscopic analysis has been greatly supported by high-level quantum-chemical calculations of the mol…
Trapping of laser-vaporized alkali metal atoms in rare-gas matrices
1999
Abstract Alkali metal atoms prepared by laser ablation of solid Li and Na are trapped in Ar, Kr, and Xe matrices and studied by electron paramagnetic resonance spectroscopy (EPR) at 15 K. Evidence for tight trapping sites, not observed for atoms generated by conventional Knudsen oven techniques, is presented. The novel tight trapping sites are characterized by a large increase in the isotropic hyperfine coupling constant and a simultaneous decrease in the isotropic g -value. Based on the EPR data, it is suggested that the observed tight trapping corresponds to single substitution of lattice atoms in Ar, Kr, and Xe matrices.