Abstract:
:The role of alveolar macrophages in the process of the human lung clearance is summarised. Three patterns of alveolar macrophage (AM) displacement on the surface of alveolus are distinguished depending on the loading of the surface with insoluble deposits, i.e. directional, directional with small stochastic noise and purely random. The physical analysis is presented of chemotactic movement and hydrodynamical effects on the residence time of AMs in a geometrical model of the human alveolus. The calculation of exit times from the alveolus is also presented. Calculations show that simultaneous passive and active displacement of AMs loaded with particles reduces exit time of the macrophage by 85%, compared to the case of purely directional movement. When active transport is reduced, due to AM overloading, exit time is determined by the passive transport rate. For reduced surfactant activity, the exit time of AM from the alveolus is the function of its chemotactic activity only and is inversely proportional to AM mobility. The exit time of AMs tends towards infinity when both mechanisms of clearance decay.
journal_name
Med Biol Eng Computjournal_title
Medical & biological engineering & computingauthors
Gradoń L,Podgórski Adoi
10.1007/BF02522517subject
Has Abstractpub_date
1995-07-01 00:00:00pages
575-81issue
4eissn
0140-0118issn
1741-0444journal_volume
33pub_type
杂志文章abstract::There is multiple evidence in the literature that a sub-threshold pre-pulse, delivered immediately prior to an electrical stimulation pulse, can alter the activation threshold of nerve fibers and motor unit recruitment characteristics. So far, previously published works combined monophasic stimuli with sub-threshold d...
journal_title:Medical & biological engineering & computing
pub_type: 杂志文章
doi:10.1007/s11517-018-1851-y
更新日期:2018-12-01 00:00:00
abstract::An eye pointer was developed as a new line-of-sight displacement analyser. It analyses an observer's eye movements and superimposes their line of vision on a TV image which is the same as their view. A newly developed miniature colour field camera and very compact eye-movement sensors are attached to a translucent rei...
journal_title:Medical & biological engineering & computing
pub_type: 杂志文章
doi:10.1007/BF02446149
更新日期:1990-07-01 00:00:00
abstract::The visco-elastic properties of living cells, measured to date by various authors, vary considerably, depending on the experimental methods and/or on the theoretical models used. In the present study, two mechanisms thought to be involved in cellular visco-elastic responses were analysed, based on the idea that the cy...
journal_title:Medical & biological engineering & computing
pub_type: 杂志文章
doi:10.1007/BF02349982
更新日期:2003-11-01 00:00:00
abstract::Vascular access for renal dialysis is a lifeline for about 120 000 individuals in the United States. Stethoscope auscultation of vascular sounds has some utility in the assessment of access patency, yet can be highly skill-dependent. The objective of the study was to identify acoustic parameters that are related to ch...
journal_title:Medical & biological engineering & computing
pub_type: 杂志文章
doi:10.1007/BF02345123
更新日期:2005-01-01 00:00:00
abstract::A system, to collect, analyse and display biological data, is developed using IBM PC AT compatibles (PCs) or CED1401/1609 devices networked to a VAX environment. It can be operated in three separate modes: using the CED/IEEE/VAX network; using the PC/Ethernet/VAX network; as a standalone PC. The original system compri...
journal_title:Medical & biological engineering & computing
pub_type: 杂志文章
doi:10.1007/BF02446881
更新日期:1993-01-01 00:00:00
abstract::Conduct disorder (CD) is an important mental health problem in childhood and adolescence. There is presently a trend of revealing neural mechanisms using measures of brain networks. This study goes further by presenting a classification scheme to distinguish subjects with CD from typically developing healthy subjects ...
journal_title:Medical & biological engineering & computing
pub_type: 杂志文章
doi:10.1007/s11517-020-02215-8
更新日期:2020-09-01 00:00:00
abstract::This study explores the analysis of a new stent geometry from two typical stents used to treat the coronary artery disease. Two different finite element methods are applied with different boundary conditions to investigate the stenosis region. Computational fluid dynamics (CFD) models including fluid-structure interac...
journal_title:Medical & biological engineering & computing
pub_type: 杂志文章
doi:10.1007/s11517-016-1574-x
更新日期:2017-06-01 00:00:00
abstract::The management of postprandial glucose excursions in type 1 diabetes has a major impact on overall glycaemic control. In this work, we propose and evaluate various mechanistic models to characterize the disposal of meal-attributable glucose. Sixteen young volunteers with type 1 diabetes were subject to a variable-targ...
journal_title:Medical & biological engineering & computing
pub_type: 杂志文章
doi:10.1007/s11517-016-1509-6
更新日期:2017-02-01 00:00:00
abstract::We introduce a novel method for an automatic classification of subjects to those with or without neuromuscular disorders. This method is based on multiscale entropy of recorded surface electromyograms (sEMGs) and support vector classification. The method was evaluated on a single-channel experimental sEMGs recorded fr...
journal_title:Medical & biological engineering & computing
pub_type: 杂志文章
doi:10.1007/s11517-010-0629-7
更新日期:2010-08-01 00:00:00
abstract::A process is described for the fabrication of silicon-based microelectrodes for neurophysiology using bonded and etched-back silicon-on-insulator (BESOI) wafers. The probe shapes are defined without high levels of boron doping in the silicon; this is considered as a step towards producing probes with active electronic...
journal_title:Medical & biological engineering & computing
pub_type: 杂志文章
doi:10.1007/BF02344773
更新日期:2000-03-01 00:00:00
abstract::The aim of the study is to establish the validity of the use of the electrical impedance technique for estimating local oedema in extremities through comparison with computed-tomography (CT) analysis. Eight healthy women (group 1) and nine women with unilateral leg oedema following chronic lymphatic obstruction (group...
journal_title:Medical & biological engineering & computing
pub_type: 杂志文章
doi:10.1007/BF02522859
更新日期:1998-01-01 00:00:00
abstract::In three-dimensional reconstruction of the human spine obtained from stereo-radiographic set-ups (two radiographs or more), it is extremely difficult to identify exactly the same landmarks on all radiographs. The effect of these identification errors was investigated with simulations made on points of known three-dime...
journal_title:Medical & biological engineering & computing
pub_type: 杂志文章
doi:10.1007/BF02446787
更新日期:1992-11-01 00:00:00
abstract::The blood cell counting and classification ensures the evaluation and diagnosis of a number of diseases. The analysis of white blood cells (WBCs) permits us to detect the acute lymphoblastic leukemia (ALL), a type of blood cancer that causes fatality when untreated. At present, the morphological analysis of blood cell...
journal_title:Medical & biological engineering & computing
pub_type: 杂志文章
doi:10.1007/s11517-020-02249-y
更新日期:2020-11-01 00:00:00
abstract::The mechanism of brain contusion has been investigated using a series of three-dimensional (3D) finite element analyses. A head injury model was used to simulate forward and backward rotation around the upper cervical vertebra. Intracranial pressure and shear stress responses were calculated and compared. The results ...
journal_title:Medical & biological engineering & computing
pub_type: 杂志文章
doi:10.1007/BF02347044
更新日期:2000-05-01 00:00:00
abstract::We have successfully developed a multiscale acoustic-resolution photoacoustic tomography system in a single imaging platform. By switching between ultrasound transducers (center frequencies 5 and 40 MHz) and optical condensers, we have photoacoustically imaged microvasculatures of small animals in vivo at different sc...
journal_title:Medical & biological engineering & computing
pub_type: 杂志文章
doi:10.1007/s11517-014-1182-6
更新日期:2016-03-01 00:00:00
abstract::Instantaneous backflow through central clearance of bileaflet heart valves at the instant of closure is investigated. An Edwards-Duromedics valve in the mitral position is employed to measure the transient pressures near the entrance and exit region in an in vitro flow chamber. A region surrounding the clearance is mo...
journal_title:Medical & biological engineering & computing
pub_type: 杂志文章
doi:10.1007/BF02510497
更新日期:1995-05-01 00:00:00
abstract::In a computer-aided diagnosis (CAD) system, especially for chest radiograph or chest X-ray (CXR) screening, CXR image view information is required. Automatically separating CXR image view, frontal and lateral can ease subsequent CXR screening process, since the techniques may not equally work for both views. We presen...
journal_title:Medical & biological engineering & computing
pub_type: 杂志文章
doi:10.1007/s11517-018-1786-3
更新日期:2018-08-01 00:00:00
abstract::Left ventricular assist device (LVAD) support unloads left ventricular (LV) pressure and volume and decreases wall stress. This study investigated the effect of systematic LVAD unloading on the 3-dimensional myocardial wall stress by employing finite element models containing layered fiber structure, active contractil...
journal_title:Medical & biological engineering & computing
pub_type: 杂志文章
doi:10.1007/s11517-014-1205-3
更新日期:2014-12-01 00:00:00
abstract::Remote patient monitoring should reduce mortality rates, improve care, and reduce costs. We present an overview of the available technologies for the remote monitoring of chronic obstructive pulmonary disease (COPD) patients, together with the most important medical information regarding COPD in a language that is ada...
journal_title:Medical & biological engineering & computing
pub_type: 杂志文章,评审
doi:10.1007/s11517-018-1798-z
更新日期:2018-04-01 00:00:00
abstract::Based on the principle of backscattering of laser radiation from tissues, a non-invasive PC-AT based reflectance imaging technique is developed. The laser beam from a semiconductor laser operating at 670 nm is guided to the tissue site by an optical fibre. The backscattered radiation is collected by another fibre plac...
journal_title:Medical & biological engineering & computing
pub_type: 杂志文章
doi:10.1007/BF02530046
更新日期:1997-05-01 00:00:00
abstract::The changes in the power spectra of single-fibre extracellular action potentials (SFEAPs) generated in an infinite anisotropic frequency-dependent volume conductor, which occurred as a result of alterations in the propagation velocity v and duration T(in) of the intracellular action potential (IAP) were analytically d...
journal_title:Medical & biological engineering & computing
pub_type: 杂志文章
doi:10.1007/BF02446167
更新日期:1992-07-01 00:00:00
abstract::A new method of stimulation of the lower extremities was devised that automatically adjusts the stimulation conditions at any angle of the knee joint. An M-wave is considered to indicate the stimulation conditions, because it is the waveform that results from direct stimulation to the axon of the alpha motor neuron. T...
journal_title:Medical & biological engineering & computing
pub_type: 杂志文章
doi:10.1007/BF02351018
更新日期:2004-01-01 00:00:00
abstract::Artifacts cause distortion and fuzziness in electroencephalographic (EEG) signal and hamper EEG analysis, so it is necessary to remove them prior to the analysis. Particularly, artifact removal becomes a critical issue in experimental protocols with significant inherent recording noise, such as mobile EEG recordings a...
journal_title:Medical & biological engineering & computing
pub_type: 杂志文章
doi:10.1007/s11517-017-1620-3
更新日期:2017-09-01 00:00:00
abstract::Spectral analysis of heart rate variability (HRV) is a widely accepted approach for assessment of cardiac autonomic function and its relationship to numerous disorders and diseases. As a rule, the non-parametric methods for HRV spectral analysis are tested using the integral pulse frequency modulation (IPFM) model. Ho...
journal_title:Medical & biological engineering & computing
pub_type: 杂志文章
doi:10.1007/BF02345290
更新日期:2001-05-01 00:00:00
abstract::Dislocation is a serious potential complication of total hip replacement. Previous studies have proposed a newly developed total hip structure that meets the required oscillation angle of 120°, for which the chamfer on the acetabular liner rim was designed to enable the neck to impinge on the chamfer over a large area...
journal_title:Medical & biological engineering & computing
pub_type: 杂志文章
doi:10.1007/s11517-017-1673-3
更新日期:2018-01-01 00:00:00
abstract::Tooth mobility examination is important in planning dental treatment, as it may give an indication of alveolar bone loss and the condition of the periodontal ligament. In clinical dental diagnosis a manual tooth mobility examination is useful. However, its determination of tooth mobility is subjective and depends on t...
journal_title:Medical & biological engineering & computing
pub_type: 杂志文章
doi:10.1007/BF02442173
更新日期:1989-01-01 00:00:00
abstract::In a computerised ultrasound image guidance for automated prostatectomy system, it is necessary to identify a smooth, continuous contour for the prostate (boundary) from the ultrasound image. The radial bas-relief (RBR) method, which has been reported previously, can extract a skeletonised image from an ultrasound ima...
journal_title:Medical & biological engineering & computing
pub_type: 杂志文章
doi:10.1007/BF02518882
更新日期:1998-11-01 00:00:00
abstract::Electromyography (EMG) in a bio-driven system is used as a control signal, for driving a hand prosthesis or other wearable assistive devices. Processing to get informative drive signals involves three main modules: preprocessing, dimensionality reduction, and classification. This paper proposes a system for classifyin...
journal_title:Medical & biological engineering & computing
pub_type: 杂志文章
doi:10.1007/s11517-018-1857-5
更新日期:2018-12-01 00:00:00
abstract::Successful identification of gastric slow waves in canine gastric electrical activity (GEA) data was achieved using a statistical data-processing procedure based on the multiple linear regression (MLR) curve fitting technique. Both distal and proximal waveforms were identified, first by construction of separate orthon...
journal_title:Medical & biological engineering & computing
pub_type: 杂志文章
doi:10.1007/BF02345076
更新日期:2002-07-01 00:00:00
abstract::Neural networks are trained to estimate the germination percentages of Plasmopara viticola oospores, overwintered in natural conditions in two viticultural areas in northern Italy, by using climatic (temperature and rainfall) data, as well as the previous germination measurement, as input variables. The 288 available ...
journal_title:Medical & biological engineering & computing
pub_type: 杂志文章
doi:10.1007/BF02344698
更新日期:2000-01-01 00:00:00