Abstract:
:In this study, the shape and the configuration of smooth muscle cells (SMCs) within the arterial wall are altered to investigate their influence on molecular transport across the media layer of the thoracic aorta wall. In a 2D geometry of the media layer containing SMCs, the finite-element method has been employed to simulate the diffusion of solutes through the media layer. The media is modeled as a heterogeneous system composed of SMCs having elliptic or circular cross sections embedded in a homogeneous porous medium made of proteoglycan and collagen fibers with an interstitial fluid filling the void. The arrangement of SMCs is in either ordered or disordered fashion for different volume fractions of SMCs. The interstitial fluid enters the media through fenestral pores, which are assumed to be distributed uniformly over the internal elastic lamina (IEL). Results revealed that in an ordered arrangement of SMCs, the concentration of adenosine 5'-triphosphate (ATP) over the surface of SMCs with an elliptic cross section is 5-8% more than those of circular SMCs in volume fractions of 0.4-0.7. The ATP concentration at the SMC surface decreases with volume fraction in the ordered configuration of SMCs. In a disordered configuration, the local ATP concentration at the SMC surface and in the bulk are strongly dependent on the distance between neighboring SMCs, as well as the minimum distance between SMCs and fenestral pores. Moreover, the SMCs in farther distances from the IEL are as important as those just beneath the IEL in disordered configurations. The results of this study lead us to better understanding of the role of SMCs in controlling the diffusion of important species such as ATP within the arterial wall.
journal_name
Med Biol Eng Computjournal_title
Medical & biological engineering & computingauthors
Dabagh M,Jalali P,Sarkomaa Pdoi
10.1007/s11517-007-0219-5subject
Has Abstractpub_date
2007-11-01 00:00:00pages
1005-14issue
11eissn
0140-0118issn
1741-0444journal_volume
45pub_type
杂志文章abstract::Peripheral arterial occlusive disease is a serious cardiovascular disorder. The arterial occlusion leads to turbulent flow and arterial sound generation on the inner vessel wall. Stenosis-induced vibro-acoustic waves propagate through the surrounding soft tissues and reach the skin surface. In this study, the feasibil...
journal_title:Medical & biological engineering & computing
pub_type: 杂志文章
doi:10.1007/s11517-019-01995-y
更新日期:2019-08-01 00:00:00
abstract::The paper describes an investigation in which it is shown that small positive voltage pulses applied to an external conductor placed against the photocathode of a photomultiplier tube can be used to switch the photocathode completely off for the duration of the pulses. This suggests that a photomultiplier tube with a ...
journal_title:Medical & biological engineering & computing
pub_type: 杂志文章
doi:10.1007/BF02441486
更新日期:1989-05-01 00:00:00
abstract::The development of an active implantable device for measuring electrocardiogram (ECG) is presented. The study is a part of a project which aims at developing implantable ECG instrumentation with wireless data and power transfer ( http://www.ele.tut.fi/tule ). The developed implant presented here has all the measuremen...
journal_title:Medical & biological engineering & computing
pub_type: 杂志文章,评审
doi:10.1007/s11517-007-0264-0
更新日期:2007-12-01 00:00:00
abstract::It is acknowledged that the first heart sound S1 consists of two major, high-frequency components M1 and T1, corresponding, respectively, to the vibrations of the mitral and tricuspid valves and their surrounding tissues following valve closure in early systole. In this study, the matching pursuit (MP) method was used...
journal_title:Medical & biological engineering & computing
pub_type: 杂志文章
doi:10.1007/BF02345436
更新日期:2001-11-01 00:00:00
abstract::Haematocrit and temperature effects on resistivity are investigated using the electrical impedance method. Measurements are made extensively for pig's blood. The experimental set-up basically involves four ring electrodes being placed around a wooden probe that is subsequently immersed into a syringe containing pig's ...
journal_title:Medical & biological engineering & computing
pub_type: 杂志文章
doi:10.1007/BF02523215
更新日期:1998-07-01 00:00:00
abstract::In acute experiments the sciatic nerve of the rat is electrically stimulated to induce fatigue in the medial Gastrocnemius muscle. Fatigue tests are carried out using intermittent stimulation of different compartments (sequential) or a single compartment (synchronous) of the sciatic nerve. The activation of different ...
journal_title:Medical & biological engineering & computing
pub_type: 杂志文章
doi:10.1007/BF02530036
更新日期:1997-05-01 00:00:00
abstract::Induction coils were fabricated based on flexible printed circuit board for inductive transcutaneous power transmission. The coil had closed magnetic circuit (CMC) structure consisting of inner and outer magnetic core. The power transmission efficiency of the fabricated device was measured in the air and in vivo condi...
journal_title:Medical & biological engineering & computing
pub_type: 杂志文章
doi:10.1007/s11517-012-0939-z
更新日期:2012-09-01 00:00:00
abstract::Hepatic echinococcosis (HE) is a life-threatening liver disease caused by parasites that requires a precise diagnosis and proper treatments. To assess HE lesions accurately, we propose a novel automatic HE lesion segmentation and classification network that contains lesion region positioning (LRP) and lesion region se...
journal_title:Medical & biological engineering & computing
pub_type: 杂志文章
doi:10.1007/s11517-020-02126-8
更新日期:2020-03-01 00:00:00
abstract::An automatic power-generating system (AGS) which converts kinetic energy into electric energy for quartz watches was tested as a power source for implantable cardiac pacemakers. An automatic power-generating mechanism and a capacitor (0.33 F) were removed from a quartz watch (SEIKO) and encapsulated in a polyvinyl cas...
journal_title:Medical & biological engineering & computing
pub_type: 杂志文章
doi:10.1007/BF02513315
更新日期:1999-05-01 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::Stroke survivors are more prone to developing cognitive impairment and dementia. Dementia detection is a challenge for supporting personalized healthcare. This study analyzes the electroencephalogram (EEG) background activity of 5 vascular dementia (VaD) patients, 15 stroke-related patients with mild cognitive impairm...
journal_title:Medical & biological engineering & computing
pub_type: 杂志文章
doi:10.1007/s11517-017-1734-7
更新日期:2018-01-01 00:00:00
abstract::An efficient and novel modeling approach is proposed in this paper for identifying proteins or genes involved in melanoma skin cancer. Two types of classifiers are modeled, based on the chemical structure and hydropathy property of amino acids. These classifiers are further implemented using NI LabVIEW-based hardware ...
journal_title:Medical & biological engineering & computing
pub_type: 杂志文章
doi:10.1007/s11517-020-02241-6
更新日期:2020-10-01 00:00:00
abstract::The purpose of this study is to verify the applicability of a sixth-order model to the mechanomyogram (MMG) system of the parallel-fibered muscle, which was identified from the MMG of the pennation muscle. The median nerve was stimulated, and an MMG and torque of the abductor pollicis brevis muscle were measured. The ...
journal_title:Medical & biological engineering & computing
pub_type: 杂志文章
doi:10.1007/s11517-013-1107-9
更新日期:2013-12-01 00:00:00
abstract::A computer-aided method was developed to automatically localize tumors in lung PET images of discrete bins within the breathing cycle, followed by an algorithm that registers all the information of a complete respiratory cycle into a single reference bin. Four registration/integration algorithms: Centroid Based, Inten...
journal_title:Medical & biological engineering & computing
pub_type: 杂志文章
doi:10.1007/s11517-009-0549-6
更新日期:2010-01-01 00:00:00
abstract::A method for accurately finding cardiac bidomain conductivity parameters is a crucial part of efforts to study and understand the electrical functioning of the heart. The bidomain model considers current flowing along (longitudinal) and across (transverse) sheets of cardiac fibres, as well as between these sheets (nor...
journal_title:Medical & biological engineering & computing
pub_type: 杂志文章
doi:10.1007/s11517-013-1101-2
更新日期:2013-12-01 00:00:00
abstract::This article presents a stimulation control method using a uniaxial gyroscope measuring angular velocity of the shank in the sagittal plane, to control functional electrical stimulation of the triceps surae to improve push-off of stroke subjects during gait. The algorithm is triggered during each swing phase of gait w...
journal_title:Medical & biological engineering & computing
pub_type: 杂志文章
doi:10.1007/s11517-009-0539-8
更新日期:2009-11-01 00:00:00
abstract::While matrix remodeling plays a key role in vascular physiology and pathology, the underlying mechanisms have remained incompletely understood. We studied the remodeling of collagen matrices by individual vascular smooth muscle cells (SMCs), clusters and monolayers. In addition, we focused on the contribution of trans...
journal_title:Medical & biological engineering & computing
pub_type: 杂志文章
doi:10.1007/s11517-012-0916-6
更新日期:2012-07-01 00:00:00
abstract::The aim of the study was to assess the wavelength dependence of the UV absorbance during monitoring of different compounds in the dialysate. UV absorbance was determined by using a double-beam spectrophotometer on dialysate samples taken at pre-determined times during dialysis, over a wavelength range of 180-380 nm. C...
journal_title:Medical & biological engineering & computing
pub_type: 杂志文章
doi:10.1007/BF02348430
更新日期:2003-05-01 00:00:00
abstract::An algorithm for determining the frequency and propagation time of the gastric slow wave has been designed for integration into a demand gastric pacing system. The algorithm analyses the serosal activity in both the time and frequency domains, and the results are compared to produce a conclusion only when the values a...
journal_title:Medical & biological engineering & computing
pub_type: 杂志文章
doi:10.1007/BF02344688
更新日期:2000-01-01 00:00:00
abstract::A technique is proposed that allows automatic decomposition of electromyographic (EMG) signals into their constituent motor unit action potential trains (MUAPTs). A specific iterative algorithm with a classification method using fuzzy-logic techniques was developed. The proposed classification method takes into accoun...
journal_title:Medical & biological engineering & computing
pub_type: 杂志文章
doi:10.1007/BF02349972
更新日期:2003-11-01 00:00:00
abstract::To describe upper airway obstruction in patients with sleep apnea syndrome, the steady state solutions of a simple model of local pharyngeal obstruction were studied. Importantly, the present model embodies a series of two individualised elements, each having its own compliance, which enables the consideration, from a...
journal_title:Medical & biological engineering & computing
pub_type: 杂志文章
doi:10.1007/BF02510972
更新日期:1997-11-01 00:00:00
abstract::A nonlinear prediction method for investigating the dynamic interdependence between short length time series is presented. The method is a generalization to bivariate prediction of the univariate approach based on nearest neighbor local linear approximation. Given the input and output series x and y, the relationship ...
journal_title:Medical & biological engineering & computing
pub_type: 杂志文章
doi:10.1007/s11517-006-0043-3
更新日期:2006-05-01 00:00:00
abstract::Partial coherence estimate between two signals removing the contribution of a periodic, deterministic one is proposed for measuring the coherence between two ongoing eletroencephalografic (EEG) activities collected at distinct cortical regions under sensory stimulation. The estimator expression was derived and shown t...
journal_title:Medical & biological engineering & computing
pub_type: 杂志文章
doi:10.1007/s11517-007-0191-0
更新日期:2007-07-01 00:00:00
abstract::The objective of this study was to evaluate the effect of following combined treatment with parathyroid hormone (1-34) (PTH) and beta-tricalcium phosphate (β-TCP) on local bone formation in a rat 3-mm critical-size defect at distal femur. Twelve weeks after bilateral ovariectomy (OVX) and sham operation (sham), all an...
journal_title:Medical & biological engineering & computing
pub_type: 杂志文章
doi:10.1007/s11517-015-1402-8
更新日期:2016-09-01 00:00:00
abstract::Mammography is a widely used screening tool and is the gold standard for the early detection of breast cancer. The classification of breast masses into the benign and malignant categories is an important problem in the area of computer-aided diagnosis of breast cancer. A small dataset of 57 breast mass images, each wi...
journal_title:Medical & biological engineering & computing
pub_type: 杂志文章
doi:10.1007/s11517-006-0077-6
更新日期:2006-08-01 00:00:00
abstract::Many studies concerning the internal work of human motion have used two-dimensional kinematic models to estimate kinetic energy of the segments. The generalised co-ordinate concept has been applied here to a simultaneous and bilateral gait analysis. A three-dimensional kinematic model based on quaternions has been dev...
journal_title:Medical & biological engineering & computing
pub_type: 杂志文章
doi:10.1007/BF02523852
更新日期:1996-11-01 00:00:00
abstract::On the basis of spatial covariance it is found that, by spatial filtering the localisation of a single dipole source, both parallel and perpendicular to the measurement plane (assuming a signal-noise ratio of 5:1), can be performed with an accuracy of < 0.5 mm. When the signal-noise ratio is increased to 30:1, the res...
journal_title:Medical & biological engineering & computing
pub_type: 杂志文章
doi:10.1007/BF02510982
更新日期:1997-11-01 00:00:00
abstract::This work addresses the problem of estimating the conduction velocity (CV) of single motor unit (MU) action potentials from surface EMG signals detected with linear electrode arrays during voluntary muscle contractions. In ideal conditions, that is without shape or scale changes of the propagating signals and with add...
journal_title:Medical & biological engineering & computing
pub_type: 杂志文章
doi:10.1007/BF02344807
更新日期:2001-03-01 00:00:00
abstract::The interactions between respiration, heart rate and blood pressure variability (HRV, BPV), are considered to be of paramount importance for the study of the functional organisation of the autonomic nervous system (ANS). The aim of the reported study is to detect and classify the intermittent phase locking (PL) phenom...
journal_title:Medical & biological engineering & computing
pub_type: 杂志文章
doi:10.1007/BF02345011
更新日期:2000-07-01 00:00:00
abstract::The passive and active properties of the cochlear outer hair cell are studied. The outer hair cell is currently considered the major candidate for the active component of mammalian hearing. Understanding of its properties may explain the amplification and sharp frequency selectivity of the ear. To analyse the cell beh...
journal_title:Medical & biological engineering & computing
pub_type: 杂志文章
doi:10.1007/BF02513294
更新日期:1999-03-01 00:00:00