Enhancement of RF Ablation by Combined Use of Ultra-Low Temperature Fluid Cooling and Magnetic Nanoparticles

2010 ◽  
Author(s):  
Zhong-Shan Deng ◽  
Jing Liu
Keyword(s):  
Magnetic Nanoparticles ◽  
Low Temperature ◽  
Bioheat Transfer ◽  
Rf Ablation ◽  
High Electrical Conductivity ◽  
Thermal Coagulation ◽  
Cooling Method ◽  
Tumor Tissues ◽  
Combined Use ◽  
Fluid Cooling

Magnetic nanoparticles with high electrical conductivity have been proved to be effective in enhancing the efficacy of RF ablation. However, the possible carbonization of tissues is an unfavorable factor in achieving greater dimensions of necrosis, because carbonized tissue is a poor conductor, increases impedance and limits propagation area of RF energy. To prevent potential carbonization of tissues surrounding to the heating part of RF electrodes during RF ablation, a new method using ultra-low temperature fluid was proposed for cooling RF electrodes and tissues in the vicinity of RF electrodes in this study. To test its feasibility, the corresponding bioheat transfer process during RF ablation simultaneously applying this cooling method and magnetic nanoparticles was studied through numerical simulations. The results indicate that the cooling method by ultra-low temperature fluid can prevent carbonization of tissues resulted by local high temperature, significantly enlarge the effective heating area and thus actualize highly efficient thermal coagulation to tumor tissues during RF ablation with adjuvant use of magnetic nanoparticles.

scholarly journals Low temperature solventless synthesis and characterization of Ni and Fe magnetic nanoparticles

2012 ◽  
Vol 48 (66) ◽  
pp. 8237 ◽  
Author(s):  
Liis Seinberg ◽  
Shinpei Yamamoto ◽  
Ruwan Gallage ◽  
Masahiko Tsujimoto ◽  
Yoji Kobayashi ◽  
...  
Keyword(s):  
Magnetic Nanoparticles ◽  
Low Temperature ◽  
Synthesis And Characterization ◽  
Solventless Synthesis

Treatment of Arrhythmias by Radiofrequency Ablation

2013 ◽  
Author(s):  
M. Erol Ulucakli ◽  
Evan P. Sheehan
Keyword(s):  
Radiofrequency Ablation ◽  
Cardiac Tissue ◽  
Clinical Applications ◽  
Bioheat Transfer ◽  
Temperature Profiles ◽  
Cellular Injury ◽  
Rf Ablation ◽  
Transcatheter Therapy ◽  
Wide Range ◽  
Primary Modality

Radiofrequency ablation may be described as a thermal strategy to destroy tissue by increasing its temperature and causing irreversible cellular injury. Radiofrequency ablation is a relatively new modality which has found use in a wide range of medical applications and gained acceptance. RF ablation has been used to destroy tumors in the liver, prostate, breasts, lungs, kidneys, bones, and eyes. One of the early clinical applications was its use in treating supraventricular arrhythmias by selectively destroying cardiac tissue. Radiofrequency ablation has become established as the primary modality of transcatheter therapy for the treatment of symptomatic arrhythmias. Radiofrequency catheter ablation of cardiac arrhythmias was investigated using a finite-element based solution of the bioheat transfer equation. Spatial and temporal temperature profiles in the cardiac tissue were visualized.

Estimation of Efficiency of Functional Additives in Winter Diesel Fuels of Different Hydrocarbon-Type Content

2021 ◽  
pp. 11-16
Author(s):  
E. A. Burov ◽  
◽  
L.V. Ivanova ◽  
V. N. Koshelev ◽  
D. A. Sandzhieva ◽  
...  
Keyword(s):  
Low Temperature ◽  
Group Composition ◽  
Component Composition ◽  
Saturated Hydrocarbons ◽  
Diesel Fuels ◽  
Functional Additives ◽  
Combined Use ◽  
Polycyclic Aromatic ◽  
Functional Actions ◽  
Lubricating Properties

The paper reviews the structural and group composition of three basic winter diesel fuels and its influence on the low-temperature and lubricating properties of fuels. It is shown that a high content of saturated hydrocarbons, primarily medium-molecular n-alkanes, and arenes with a higher proportion of substitution leads to a deterioration of low-temperature properties. A decrease in the proportion of medium-molecular alkanes and even a slight increase in the content of bi - and polycyclic aromatic hydrocarbons impairs the lubricating properties of the fuel.The influence of the component composition of diesel fuels on the effectiveness of anti-wear and depressor-dispersing additives was noted. The study of compatibility of additives of different functional actions revealed that the anti-wear additive based on fatty acids of tallow oil does not affect the activity of the depressant-dispersing additive, while the combined use of these additives slightly worsens the lubricating properties, but does not lead this indicator beyond the established standards.

Development of Magnetic Nanoparticles as Microwave-Specific Catalysts for the Rapid, Low-Temperature Synthesis of Formalin Solutions

ACS Catalysis ◽  
2013 ◽  
Vol 3 (6) ◽  
pp. 1318-1323 ◽  
Author(s):  
Mark Crosswhite ◽  
Jacob Hunt ◽  
Taylor Southworth ◽  
Kyle Serniak ◽  
Anthony Ferrari ◽  
...  
Keyword(s):  
Magnetic Nanoparticles ◽  
Low Temperature ◽  
Low Temperature Synthesis ◽  
Temperature Synthesis

Fluid Convection Models for Low-Temperature Grinding and Effect of Fluid Warming

2020 ◽  
Vol 143 (2) ◽  
Author(s):  
Lei Zhang ◽  
W. Brian Rowe
Keyword(s):  
Low Temperature ◽  
Convection Heat Transfer ◽  
Wheel Speed ◽  
Convection Heat Transfer Coefficient ◽  
Mineral Oils ◽  
Basic Assumptions ◽  
Fluid Convection ◽  
Heat Dispersion ◽  
Fluid Cooling ◽  
Experimental Values

Abstract The paper considers fluid convection in low-temperature grinding. Fluid cooling often predominates over all other forms of heat dispersion in the grinding zone particularly in low-temperature grinding. Experimental values of convection heat transfer coefficient (CHTC) up to and in excess of 200,000 W/m2K have been found by various researchers both for water-based emulsions and in one case for mineral oils employed in high wheel-speed grinding. Several convection models have been developed in recent years for the prediction of CHTCs in low-temperature grinding. This paper reviews advances in convection modeling and reconsiders the basic assumptions implied. A proposal is made for improved estimation for highly churned flow assuming a degree of fluid warming. Predicted coefficients are compared with measured values.

scholarly journals Adverse Interaction between Capecitabine and Warfarin Resulting in Altered Coagulation Parameters: A Review of the Literature Starting from a Case Report

2010 ◽  
Vol 2010 ◽  
pp. 1-4 ◽  
Author(s):  
Giovanni Giunta
Keyword(s):  
Cytochrome P450 ◽  
Antineoplastic Agent ◽  
Liver Microsomes ◽  
Metastatic Breast ◽  
Concomitant Administration ◽  
Current Data ◽  
Tumor Tissues ◽  
Combined Use ◽  
Orally Active

Capecitabine is an orally active prodrug of fluorouracil and is extensively used as an antineoplastic agent. It is converted to 5-Fluorouracil in the liver and tumor tissues. Warfarin is an anticoagulant agent for preventing and treating venous and arterial thrombosis and embolism and is metabolized by cytochrome P450 isoenzymes in the liver. Preclinical in vitro studies using human liver microsomes report no inhibitory effects between capecitabine and substrates of cytochrome P. However, the concomitant administration of capecitabine and warfarin resulted in INR elevation in the cases previously reported in the literature. The exact mechanism of this interaction is unknown but may be related to downregulation of cytochrome P450 2C9 by capecitabine or its metabolites. We report on the possible adverse interaction between capecitabine and warfarin in a patient with metastatic breast cancer and critically review the existing literature on this topic. Physicians should be aware of adverse reactions arising from the combined use of capecitabine and warfarin. In the light of the current data, INR levels should be closely monitored in patients using these drugs together.

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