Sökresultat

Filtyp

Din sökning på "*" gav 533929 sökträffar

Cross-vendor transfer and RF coil comparison of a high-resolution MP2RAGE protocol for brain imaging at 7T

Abstrakt. Ett etablerat MP2RAGE-protokoll för semikvantitativ strukturell hjärn-MRI överfördes frånen 7T MR-skanner till en annan leverantör med jämförbar hårdvara, men motsatt polaritet. På det härsystemet, kan skanningstiden reduceras från 11 till 8 minuter genom elliptisk k-space-sampling. Tre konfigurationerav radiofrekvens (RF) överföring jämfördes (enkelkanal med kvadraturen slits, två och åAbstract. An established MP2RAGE protocol for semi-quantitative structural brain MRI was transferred from one 7T MR scanner to that of another vendor featuring comparable hardware, but opposite polarity. On this system, the scan time could be reduced from 11 to 8 minutes by elliptical k-space sampling. Three configurations of radio-frequency (RF) transmission were compared (single channel with qua

Effect of high voltage pulses on survival of Chinese hamster V79 lung fibroblast cells

The objective is to study the effect of high voltage pulses on living cells to find the most effective combination of physical parameters to be used in tumour therapy. Four parameters that affect the cell survival are the pulse shape, electric field strength, pulse length and the number of pulses and their cell killing effect were investigated in this work. High voltage square wave or exponentiall

Endometrial destruction by thermal coagulation : Evaluation of a new form of treatment for menorrhagia

Objective. To report the first clinical evaluation of a new balloon endometrial, thermal destruction system Cavaterm®, for outpatient treatment of menorrhagia. Design. To elucidate possible technical problems during treatment, to evaluate how the patients tolerated the treatment and to judge which patients were suitable for this form of treatment. Main outcome measures. Measurements of bleeding vo

Thermal conductivity of uterine tissue in vitro

Thermotherapy of the uterus has emerged as an alternative to hysterectomy in the treatment of menorrhagia, from whence it follows that the thermal properties of uterine tissue have become of importance. This study presents measurements of the thermal conductivity and the water content of uterine tissue in vitro. A steady-state thermal conductivity apparatus, based on the comparison of test samples

Numerical calculations of temperature distribution resulting from intracavitary heating of the uterus

Objective To estimate, using numerical calculations, the depth of tissue damage in the uterus following balloon thermal endometrial destruction. Design A parameter, therapeutic depth, was defined. This was the maximum depth into the uterine myometrium, from the uterine cavity, at which a predefined temperature was reached after a certain time and with a constant intracavitary temperature. Setting

Repeated immunotherapy using intratumoural injection with recombinant interleukin-2 and tumour-infiltrating lymphocytes inhibits growth of breast cancer and induces apoptosis of tumour cells

This study tested the effect of repeated intratumoural injection with recombinant interleukin-2 (rIL-2) and tumour-infiltrating lymphocytes (TILs) on inhibition of growth of breast cancer and on induction of apoptosis of tumour cells. The tumour cell line LDLX43 was used to induce breast cancer in Wistar rats. Group I (10 rats) was the control. Group II (12 rats) received repeated intratumoural in

Endometrial destruction by hyperthermia - A possible treatment of menorrhagia : An experimental study

Background. Treatment of menorrhagia by heat-destruction of the endometrium, intended to be an alternative to hysterectomy, was investigated in an experimental study. Method. A specially designed catheter (Cavaterm™) with a silicone balloon containing a self-regulating heating element is inserted into the uterus, rilled with glycine to a pressure of around 180 mmHg and heated to about 75°C. We inv

Permeability of the blood‐brain barrier induced by 915 MHz electromagnetic radiation, continuous wave and modulated at 8, 16, 50, and 200 Hz

Biological effects of electromagnetic fields (EMF) on the blood‐brain barrier (BBB) can be studied in sensitive and specific models. In a previous investigation of the permeability of the blood‐brain barrier after exposure to the various EMF‐components of proton magnetic resonance imaging (MRI), we found that the exposure to MRI induced leakage of Evans Blue labeled proteins normally not passing t

A current injecting device for electrical impedance tomography

Electrical impedance tomography (EIT) has to be improved in order to become an accepted diagnostic technique in clinical use. The aim of this study is to improve the hardware of this technique and preferably upgrade the current injecting device. Instead of using a constant current generator the idea is to implement a voltage source and measure current accurately, in order to improve the resolution

Electromagnetic field calculations used for exposure experiments on small animals in TEM-cells

Three-dimensional electromagnetic calculations for loaded transverse electromagnetic (TEM) transmission cells are presented. Based on those calculations a prediction of the perturbation of the standard uniform field in the TEM-cell, due to the scattering by inhomogeneous structures placed inside the cell cavity, is given. The influence of the dimensions of a lossy structure and its position in the

Permeability of the blood-brain barrier induced by 915 MHz electromagnetic radiation, continuous wave and modulated at 8, 16, 50 and 200 Hz

The biological effects of electromagnetic fields (EMFs) on the blood-brain barrier (BBB) can be studied in sensitive and specific models. In a previous investigation of the permeability of the BBB after exposure to the various EMF -components of proton magnetic resonance imaging (MRI), we found that exposure to MRI induced leakage of Evans-blue-labelled proteins which do not normally pass the BBB

Experimental studies of brain tumour development during exposure to continuous and pulsed 915 MHz radiofrequency radiation

It has been suggested that electromagnetic fields (EMFs) act as a promoter late in the carcinogenesis process. To date, however, noconvincing laboratory evidence has been obtained indicating that EMFs cause tumour promotion at non-thermal exposure levels. The effects of EMF exposure in a rat brain glioma model were investigated. The exposure consisted of 915 MHz microwaves, both as continuous wave

Native word order processing is not uniform : An ERP study of verb-second word order

Studies of native syntactic processing often target phrase structure violations that do not occur in natural production. In contrast, this study examines how variation in basic word order is processed, looking specifically at structures traditionally labelled as violations but that do occur naturally. We examined Swedish verb-second (V2) and verb-third (V3) word order-processing in adult native Sw

Proposed Classification of Incision Complications: Analysis of a Prospective Study on Elective Open Lower - Limb Revascularization.

Background: Incision complications (IC) have a significant impact on procedure-related morbidity after lower-limb revascularization. One of the most studied IC is surgical site infection (SSI). Reporting these complications in a uniform way is crucial to evaluate treatment approaches. The aim of this study was to propose a comprehensive classification of IC and apply it to compare SSI with other I

Vad innebär digitalisering och autonoma teknologier för individer och samhälle?

Stefan Larssons kapitel placerar in dagens artificiella intelligens (AI) i sin digitala samtidshistoriska kontext — relationen till plattformar och internet som nätverk — och fördjupar därefter bilden av de mänskliga farhågorna med autonoma teknologier. Stefan visar på samspelet mellan databeroende AI och samhällets värderingar, och lyfter fram några av de demokratiska utmaningar som följer i kölv

Robust terrain-aided navigation through sensor fusion

To make autonomous, affordable ships feasible in the real world, they must be capable of safely navigating without fully relying on GPS, high-resolution 3D maps, or high-performance navigation sensors. We suggest a method for estimating the position using affordable navigation sensors (compass and speed log or inertial navigation sensor), sensors used for perception of the environment (cameras, ec