Search results for "Testing"

Functional MRI of the lung using hyperpolarized 3-helium gas

2004

Lung imaging has traditionally relied on x-ray methods, since proton MRI is limited to some extent by low proton density in the lung parenchyma and static field inhomogeneities in the chest. The relatively recent introduction of MRI of hyperpolarized noble gases has led to a rapidly evolving field of pulmonary MRI, revealing functional information of the lungs, which were hitherto unattainable. This review article briefly describes the physical background of the technology, and subsequently focuses on its clinical applications. Four different techniques that have been used in various human investigations are discussed: ventilation distribution, ventilation dynamics, and small airway evaluat…

Ultrasonography of the Lung.

2019

 High diagnostic accuracy, increasing clinical experience and technical improvements are good reasons to consider lung ultrasound (US) for the assessment of pleural and pulmonary diseases. In the emergency room and in intensive care, it is well acknowledged, but application in other settings is rare. The aim of this review is to update potential users in general radiology about the diagnostic scope of lung US and to encourage more frequent use of this generally underestimated lung imaging modality. Literature review was done independently by the two authors in MEDLINE (via PubMed) covering a time span from 2002 until 2017 using free text and Medical Subject Headings/MeSH. Article selection …

3He MRI in healthy volunteers: preliminary correlation with smoking history and lung volumes

2000

MRI with hyperpolarized helium-3 (3He) provides high-resolution imaging of ventilated airspaces. The first aim of this 3He-study was to compare observations of localized signal defects in healthy smokers and non-smokers. A second aim was to describe relationships between parameters of lung function, volume of inspired 3He and signal-to-noise ratio. With Ethics Committee approval and informed consent, 12 healthy volunteers (seven smokers and five non-smokers) were studied. Imaging was performed in a 1.5 T scanner using a two-dimensional FLASH sequence at 30V transmitter amplitude (TR/TE/α = 11 ms/4.2 ms/<10°). Known amounts of 3He were inhaled from a microprocessor-controlled delivery device…

The relationship between asthma and allergic rhinitis: exploring the basis for a common pathophysiology

2003

Summary Most patients with asthma also have rhinitis, and the same inflammatory cells and mechanisms are present in bronchial and nasal mucosa, thus leading to the concept of ‘one airway, one disease’. This concept is further substantiated by evidence of nasal inflammation in asthma, and bronchial inflammation and hyperresponsiveness in rhinitis. Endobronchial allergen challenge induces nasal and bronchial symptoms as well as reductions in pulmonary function and nasal patency. Likewise, treating rhinitis can improve the symptoms of asthma. There are some notable pathophysiological differences between the nose and the bronchi, for example airway remodelling appears to be less extensive in th…

Functional magnetic resonance imaging of the lung

2003

Ekspiratorisk flow avgrensingar under fysisk belastning hos ungdommar med astma : Før og etter 10 vekers intervensjon

2019

Masteroppgave folkehelsevitenskap ME516 - Universitetet i Agder 2019 Background:Asthma is a chronic inflammatory disorder associated with variable airflo w obstruction and bronchial hyperresponsivness. Asthma may interfere with the ability of childre n and adolescents to participatein physical activity, as well ascreatebarriers towards involvement. Physical activity is an important stimulus for asthma symptoms. Exercise-induced bronchoconstriction is traditionally used when physical activity is the cause of asthma symptoms, but this is measured after exercise. There is little knowledge about flow limitat io n during exercise. Aim:The purpose of this study is to investigate expiratory flow l…

DNA nanofilm thickness measurement on microarray in air and in liquid using an atomic force microscope.

2005

International audience; The measurement of the thickness of DNA films on microarray as a function of the medium (liquid, air) is gaining importance for understanding the signal response of biosensors. Thiol group has been used to attach DNA strands to gold micropads deposited on silicon surface. Atomic force microscopy (AFM) was employed in its height mode to measure the change in the pad thickness and in its force mode to measure the indentation depth of the nanofilm. A good coherence between the height and force modes is observed for the film thickness in air. The adhesion force was found to be an alternative way to measure the surface coverage of the biolayer at nanoscopic scale. However…

The EORTC computer-adaptive tests measuring physical functioning and fatigue exhibited high levels of measurement precision and efficiency

2013

Objectives: The European Organisation for Research and Treatment of Cancer (EORTC) Quality of Life Group is developing a computer-adaptive test (CAT) version of the EORTC Quality of Life Questionnaire (QLQ-C30). We evaluated the measurement properties of the CAT versions of physical functioning (PF) and fatigue (FA) and compared these with the corresponding QLQ-C30 scales. Study Design and Setting: Based on international samples of more than 1,000 cancer patients, we simulated CAT administration of varying numbers of items and compared the resulting scores with those based on all items in the respective item pools. Furthermore, the relative validity (RV) of CATs was compared with that of th…

Relevance of Tool Life Testing for Tool Replacement Strategies

1986

Several analytical and simulation models have been proposed in order to select the optimal tool replacement strategies both in single and multi-tool machining operations. All of these models, however, assume as known the probability density function that describes the stochastic behaviour of tool life. The costly efforts required in order to achieve an accurate estimate of the p.d.f. limits the use in the shop practice of the above models.

Scrutiny of the Failure of Lipid Membranes As A Function of Headgroups, Chain Length, and Lamellarity Measured by Scanning Force Microscopy

2004

AbstractA fast, quantitative, and unambiguous screening of material properties of biomembranes using scanning force microscopy in pulsed force mode on lipid membranes is presented. The spatially resolved study of breakthrough force, breakthrough distance, adhesion, stiffness, and topography of lipid membranes as determined simultaneously by digitalized pulsed force mode provides new insight into the structure-function relationship of model membranes, which are systematically analyzed by varying chain length, lipid headgroup, and lamellarity. For this purpose, a novel unbiased analysis method is presented. A strong correlation between adhesion and breakthrough events is found on lipid bilaye…