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Morton Friedman

Professor Emeritus of Biomedical Engineering
Biomedical Engineering
Box 90281, Durham, NC 27708-0281
1427 Fciemas, Box 90281, Durham, NC 27708

Selected Publications


Integrative biomechanics: A paradigm for clinical applications of fundamental mechanics

Journal Article Journal Of Biomechanics · July 2009 Integrative biomechanics uses biomechanics knowledge and methods at multiple scales and among biological entities to address fundamental and clinical problems at the tissue and organ level. Owing to the large ranges of scale involved, integrative biomechan ... Cite

Cataloguing the geometry of the human coronary arteries: a potential tool for predicting risk of coronary artery disease.

Journal Article International journal of cardiology · June 2009 BackgroundThe non-uniform distribution of atherosclerosis in the human vasculature suggests that local fluid dynamics or wall mechanics may be involved in atherogenesis. Thus certain aspects of vascular geometry, which mediates both fluid dynamics ... Full text Cite

Estimation of the transverse strain tensor in the arterial wall using ivus image registration

Journal Article Ultrasound In Medicine And Biology · November 2008 Intravascular ultrasound (IVUS) elastography is an imaging technique that obtains the local mechanical properties of the artery wall and atherosclerotic plaques through strain measurements using IVUS. Knowledge of these mechanical properties may provide cr ... Cite

Measurement of the transverse strain tensor in the coronary arterial wall from clinical intravascular ultrasound images.

Journal Article Journal of biomechanics · October 2008 Atherosclerotic plaque rupture is the major cause of acute coronary syndromes. Currently, there is no reliable diagnostic tool to predict plaque rupture. Knowledge of plaque mechanical properties based on local artery wall strain measurements would be usef ... Full text Cite

In vivo differences between endothelial transcriptional profiles of coronary and iliac arteries revealed by microarray analysis

Journal Article American Journal Of Physiology-heart And Circulatory Physiology · October 2008 Endothelial cells (ECs) from different vascular beds display a remarkable heterogeneity in both structure and function. Phenotypic heterogeneity among arterial ECs is particularly relevant to atherosclerosis since the disease occurs predominantly in major ... Cite

Individual and combined effects of shear stress magnitude and spatial gradient on endothelial cell gene expression

Journal Article American Journal Of Physiology-heart And Circulatory Physiology · November 2007 Individual and combined effects of shear stress magnitude and spatial gradient on endothelial cell gene expression. Am J Physiol Heart Circ Physiol 293: H2853-H2859, 2007. First published August 31, 2007; doi:10.1152/ajpheart.00244.2007. The apparent tende ... Cite

Frequency-dependent response of the vascular endothelium to pulsatile shear stress.

Journal Article American journal of physiology. Heart and circulatory physiology · July 2007 As a result of the complex blood flow patterns that occur in the arterial tree, certain regions of the vessel wall experience fluctuations in shear stress that are dominated by harmonic frequencies higher than the heart rate (11). To assess whether variati ... Full text Cite

Statistical hemodynamics: a tool for evaluating the effect of fluid dynamic forces on vascular biology in vivo.

Journal Article Journal of biomechanical engineering · December 2006 BackgroundIn vivo experimentation is the most realistic approach for exploring the vascular biological response to the hemodynamic stresses that are present in life. Post-mortem vascular casting has been used to define the in vivo geometry for hem ... Full text Cite

Correspondence of low mean shear and high harmonic content in the porcine iliac arteries.

Journal Article Journal of biomechanical engineering · December 2006 BackgroundTemporal variations in shear stress have been suggested to affect endothelial cell biology. To better quantify the range of dynamic shear forces that occur in vivo, the frequency content of shear variations that occur naturally over a ca ... Full text Cite

Effect of hypercholesterolemia on transendothelial EBD-albumin permeability and lipid accumulation in porcine iliac arteries.

Journal Article Atherosclerosis · February 2006 Hypercholesterolemia is associated with increased cardiovascular mortality and is known to promote the advancement of atherosclerotic lesions in experimental animal models. Juvenile swine were fed a normal or high-cholesterol diet, and the transendothelial ... Full text Cite

Interaction of wall shear stress magnitude and gradient in the prediction of arterial macromolecular permeability

Journal Article Ann. Biomed. Eng. (USA) · 2005 Large spatial shear stress gradients have anecdotally been associated with early atherosclerotic lesion susceptibility in vivo and have been proposed as promoters of endothelial cell dysfunction in vitro. Here, experiments are presented in which several me ... Full text Link to item Cite

Blood flow in major blood vessels-modeling and experiments

Journal Article Ann. Biomed. Eng. (USA) · 2005 Although primarily motivated by an interest in atherosclerosis, modeling of arterial blood flow is also important to an understanding of congenital effects and to improvements in therapeutics. A variety of methods are available to estimate the flow field i ... Full text Link to item Cite

Influence of curvature dynamics on pulsatile coronary artery flow in a realistic bifurcation model

Journal Article J. Biomech. (UK) · 2004 The coronary arteries undergo large dynamic variations during each cardiac cycle due to their position on the beating heart. The local artery curvature varies significantly. In this study the influence of dynamic curvature on coronary artery hemodynamics i ... Full text Link to item Cite

Integrative biomechanics: A paradigm for clinical applications of fundamental mechanics

Journal Article Journal Of Biomechanics · July 2009 Integrative biomechanics uses biomechanics knowledge and methods at multiple scales and among biological entities to address fundamental and clinical problems at the tissue and organ level. Owing to the large ranges of scale involved, integrative biomechan ... Cite

Cataloguing the geometry of the human coronary arteries: a potential tool for predicting risk of coronary artery disease.

Journal Article International journal of cardiology · June 2009 BackgroundThe non-uniform distribution of atherosclerosis in the human vasculature suggests that local fluid dynamics or wall mechanics may be involved in atherogenesis. Thus certain aspects of vascular geometry, which mediates both fluid dynamics ... Full text Cite

Estimation of the transverse strain tensor in the arterial wall using ivus image registration

Journal Article Ultrasound In Medicine And Biology · November 2008 Intravascular ultrasound (IVUS) elastography is an imaging technique that obtains the local mechanical properties of the artery wall and atherosclerotic plaques through strain measurements using IVUS. Knowledge of these mechanical properties may provide cr ... Cite

Measurement of the transverse strain tensor in the coronary arterial wall from clinical intravascular ultrasound images.

Journal Article Journal of biomechanics · October 2008 Atherosclerotic plaque rupture is the major cause of acute coronary syndromes. Currently, there is no reliable diagnostic tool to predict plaque rupture. Knowledge of plaque mechanical properties based on local artery wall strain measurements would be usef ... Full text Cite

In vivo differences between endothelial transcriptional profiles of coronary and iliac arteries revealed by microarray analysis

Journal Article American Journal Of Physiology-heart And Circulatory Physiology · October 2008 Endothelial cells (ECs) from different vascular beds display a remarkable heterogeneity in both structure and function. Phenotypic heterogeneity among arterial ECs is particularly relevant to atherosclerosis since the disease occurs predominantly in major ... Cite

Individual and combined effects of shear stress magnitude and spatial gradient on endothelial cell gene expression

Journal Article American Journal Of Physiology-heart And Circulatory Physiology · November 2007 Individual and combined effects of shear stress magnitude and spatial gradient on endothelial cell gene expression. Am J Physiol Heart Circ Physiol 293: H2853-H2859, 2007. First published August 31, 2007; doi:10.1152/ajpheart.00244.2007. The apparent tende ... Cite

Frequency-dependent response of the vascular endothelium to pulsatile shear stress.

Journal Article American journal of physiology. Heart and circulatory physiology · July 2007 As a result of the complex blood flow patterns that occur in the arterial tree, certain regions of the vessel wall experience fluctuations in shear stress that are dominated by harmonic frequencies higher than the heart rate (11). To assess whether variati ... Full text Cite

Statistical hemodynamics: a tool for evaluating the effect of fluid dynamic forces on vascular biology in vivo.

Journal Article Journal of biomechanical engineering · December 2006 BackgroundIn vivo experimentation is the most realistic approach for exploring the vascular biological response to the hemodynamic stresses that are present in life. Post-mortem vascular casting has been used to define the in vivo geometry for hem ... Full text Cite

Correspondence of low mean shear and high harmonic content in the porcine iliac arteries.

Journal Article Journal of biomechanical engineering · December 2006 BackgroundTemporal variations in shear stress have been suggested to affect endothelial cell biology. To better quantify the range of dynamic shear forces that occur in vivo, the frequency content of shear variations that occur naturally over a ca ... Full text Cite

Effect of hypercholesterolemia on transendothelial EBD-albumin permeability and lipid accumulation in porcine iliac arteries.

Journal Article Atherosclerosis · February 2006 Hypercholesterolemia is associated with increased cardiovascular mortality and is known to promote the advancement of atherosclerotic lesions in experimental animal models. Juvenile swine were fed a normal or high-cholesterol diet, and the transendothelial ... Full text Cite

Interaction of wall shear stress magnitude and gradient in the prediction of arterial macromolecular permeability

Journal Article Ann. Biomed. Eng. (USA) · 2005 Large spatial shear stress gradients have anecdotally been associated with early atherosclerotic lesion susceptibility in vivo and have been proposed as promoters of endothelial cell dysfunction in vitro. Here, experiments are presented in which several me ... Full text Link to item Cite

Blood flow in major blood vessels-modeling and experiments

Journal Article Ann. Biomed. Eng. (USA) · 2005 Although primarily motivated by an interest in atherosclerosis, modeling of arterial blood flow is also important to an understanding of congenital effects and to improvements in therapeutics. A variety of methods are available to estimate the flow field i ... Full text Link to item Cite

Influence of curvature dynamics on pulsatile coronary artery flow in a realistic bifurcation model

Journal Article J. Biomech. (UK) · 2004 The coronary arteries undergo large dynamic variations during each cardiac cycle due to their position on the beating heart. The local artery curvature varies significantly. In this study the influence of dynamic curvature on coronary artery hemodynamics i ... Full text Link to item Cite

Quantification of cross-sectional artery wall motion with IVUS image registration

Journal Article Proc. SPIE - Int. Soc. Opt. Eng. (USA) · 2004 Atherosclerotic lesions have been shown to have different mechanical properties than the non-diseased artery. Calculating vessel wall strain from cross-sectional vessel wall motions allows for the measurement of local stiffness. In this paper, a robust met ... Full text Link to item Cite

Comparison of coronary artery dynamics pre- and post-stenting.

Journal Article Journal of biomechanics · May 2003 Stents have dramatically improved the treatment of coronary artery disease. Since the implantation of stents changes the geometry and dynamics of the coronary artery, it is reasonable to hypothesize that some of these changes may have an important effect o ... Full text Cite

Retrieval of cardiac phase from IVUS sequences

Journal Article Proc. SPIE - Int. Soc. Opt. Eng. (USA) · 2003 Most of the quantitative measures from intravascular ultrasound (IVUS) images vary with the cardiac cycle. Although ECG-gated acquisition can prevent the pulsations from influencing the measurements, it may extend the acquisition time, and furthermore, ver ... Full text Link to item Cite

Effects of cardiac motion on right coronary artery hemodynamics

Journal Article Ann. Biomed. Eng. (USA) · 2003 The purpose of this work was to investigate the effects of physiologically realistic cardiac-induced motion on hemodynamics in human right coronary arteries. The blood flow patterns were numerically simulated in a modeled right coronary artery (RCA) having ... Full text Link to item Cite

Modeling the adaptive permeability response of porcine iliac arteries to acute changes in mural shear

Journal Article Ann. Biomed. Eng. (USA) · 2003 The hypothesis that much of the uptake of macromolecules by the vascular wall takes place while the endothelial lining is adapting to changes in its hemodynamic environment is being tested by a series of in vivo measurements of the uptake of Evans-blue-dye ... Full text Link to item Cite

Model-based shear stress gradient in realistic vascular flows and its relation to arterial macromolecular permeability

Journal Article American Society of Mechanical Engineers, Bioengineering Division (Publication) BED · 2003 Evans blue dye (EBD) was injected into the carotid arteries of three anesthetized pigs and allowed to circulate for 90 minutes. At the conclusion of the 90-minute period, the animals were sacrificed and injection casts of the infrarenal aorta and iliac-fem ... Cite

Coronary artery dynamics in vivo

Journal Article Ann. Biomed. Eng. (USA) · 2002 There is considerable evidence that the localization and evolution of vascular disease are mediated, at least in part, by mechanical factors. The mechanical environment of the coronary arteries, which are tethered to the beating heart, is influenced by car ... Full text Link to item Cite

2002 NVTherm improvements

Journal Article Proc. SPIE - Int. Soc. Opt. Eng. (USA) · 2002 The Windows version of the Night Vision Thermal Imaging System Performance Model, NVTherm, was released in March 2001. NVTherm provides accurate predictions of sensor performance for both well-sampled and undersampled thermal imagers. Since its initial fie ... Full text Link to item Cite

Variability of 3D arterial geometry and dynamics, and its pathologic implications

Journal Article Biorheology (Netherlands) · 2002 Geometric parameters and features vary within the vasculature. Furthermore, at any given anatomic site, there are substantial variations in geometry among individuals. These variations can contribute to a corresponding variability in the hemodynamic enviro ... Cite

IVUS image segmentation based on contrast

Journal Article Proc. SPIE - Int. Soc. Opt. Eng. (USA) · 2002 We present a new method to segment the walls of coronary arteries in IVUS (intravascular ultrasound) images based on a deformable model, which integrates both edge and region information. The whole image is supposed to have three regions-lumen, vessel wall ... Full text Link to item Cite

Biomechanical approaches to atherosclerosis

Journal Article Annals of Biomedical Engineering · 2002 Full text Link to item Cite

Traditional engineering in the biological century: the biotraditional engineer

Journal Article Trans. ASME, J. Biomech. Eng. (USA) · 2001 The increasing importance of life science in all engineering is prompting departments in the traditional engineering disciplines to offer life science as part of their curricula. Students who take advantage of this opportunity-“biotraditional enginee ... Full text Link to item Cite

Curvature effects on bifurcating coronary artery flow

Journal Article American Society of Mechanical Engineers, Bioengineering Division (Publication) BED · 2001 The curvature effects on bifurcating coronary artery flow were discussed. A mathematical model was developed that employed the modified Navier-Stokes equations to describe the flow in a time-dependent geometry with large externally imposed boundary motion. ... Cite

Vessel tracking by template string in angiography

Journal Article Proc. SPIE - Int. Soc. Opt. Eng. (USA) · 2001 The motion of coronary arteries has attracted more and more attention because of its possible effects on the development of atherosclerosis and potential clinical application for diagnosis of cardiovascular disease. Angiography is the best clinical modalit ... Full text Link to item Cite

The effect of celiac and renal artery outflows on near-wall velocities in the porcine iliac arteries

Journal Article Ann. Biomed. Eng. (USA) · 2000 The effects of the outflow of aortic blood through the celiac and renal arteries on the flow field in the external iliac arteries were studied under steady and physiologically realistic pulsatile flow conditions. Laser Doppler velocimetry (LDV) measurement ... Full text Link to item Cite

Method for assessing the need for case-specific hemodynamics: application to the distribution of vascular permeability

Journal Article Ann. Biomed. Eng. (USA) · 2000 A common approach to understanding the role of hemodynamics in atherogenesis is to seek relationships between parameters of the hemodynamic environment, and the distribution of tissue variables thought to be indicative of early disease. An important questi ... Full text Link to item Cite

Effect of periodic alterations in shear on vascular macromolecular uptake

Journal Article Biorheology (Netherlands) · 2000 Experiments were carried out in swine to test the hypothesis that changes in the fluid dynamic environment of the arterial wall, with time constants of several minutes to perhaps a few hours, prompt adaptive responses that transiently increase endothelial ... Cite

Quantification of 3-D coronary arterial motion using clinical biplane cineangiograms

Journal Article Int. J. Card. Imaging (Netherlands) · 2000 Speculation that the motion of the coronary arteries might be involved in the pathogenesis of coronary atherosclerosis has generated growing interest in the study of this motion. Accordingly, a system has been developed to quantify 3-D coronary arterial mo ... Full text Link to item Cite

Dynamics of human coronary arterial motion and its potential role in coronary atherogenesis

Journal Article Trans. ASME, J. Biomech. Eng. (USA) · 2000 Mechanical forces have been widely recognized to play an important role in the pathogenesis of atherosclerosis. Since coronary arterial motion modulates both vessel wall mechanics and fluid dynamics, it is hypothesized that certain motion patterns might be ... Full text Link to item Cite

3-dimensional particle tracking velocimetry measurements of near-wall shear in human left coronary arteries

Journal Article Annals of Biomedical Engineering · 2000 In this study, near-wall velocity measurements were obtained to estimate wall shear stress in human left coronary arteries due to their small diameter and the limitations of conventional measurement techniques. A 3-dimensional particle Tracking Velocimetry ... Cite

Direct flow analysis on a reconstructed 3D image of a physiologic porcine aortic trifurcation

Journal Article American Society of Mechanical Engineers, Bioengineering Division (Publication) BED · 1999 The present study describes a detailed methodology, from 3D image reconstruction to flow analysis, for simulating the flow field in real arterial geometries. The procedure takes advantage of the latest state of the art technology in solid modeling, and is ... Cite

Modeling the effect of alternating shear levels on the uptake of albumin by the porcine iliac arteries

Journal Article American Society of Mechanical Engineers, Bioengineering Division (Publication) BED · 1999 Experiments are being carried out in swine to test the hypothesis that changes in the fluid dynamic environment of the arterial wall, with time constants of several minutes to perhaps a few hours, prompt adaptive responses that transiently increase endothe ... Cite

Effect of alterations in femoral artery flow on abdominal vessel hemodynamics in swine

Journal Article Biorheology (Netherlands) · 1999 In support of an in vivo investigation in swine of the influence of changes in fluid dynamic wall shear on arterial macromolecular permeability, a procedure has been developed to alter the flows in the porcine posterior arterial vasculature by opening and ... Cite

Relationship between the dynamics of coronary arteries and coronary atherosclerosis

Journal Article American Society of Mechanical Engineers, Bioengineering Division (Publication) BED · 1999 Using a system developed to track and quantify the in vivo motion of coronary arteries from clinical biplane coronary cineangiograms, the in vivo dynamics of twelve coronary arteries were characterized. The results suggest that certain dynamic parameters o ... Cite

Dynamics of coronary artery curvature obtained from biplane cineangiograms

Journal Article J. Biomech. (UK) · 1998 A system was developed to track the centerlines (axes) of human coronary arteries during the cardiac cycle from biplane cineangiograms. The system employs a time interpolation technique on one image plane and a smoothing technique on the other to create si ... Full text Link to item Cite

Estimation of surgically manipulated fluid shear stresses in the abdominal vessels of swine from measured femoral artery flows

Journal Article American Society of Mechanical Engineers, Bioengineering Division (Publication) BED · 1998 In support of an in vivo investigation in swine of the influence of changes in fluid dynamic wall shear on arterial macromolecular permeability, a procedure has been developed to alter the flows in the porcine posterior arterial vasculature by opening and ... Cite

Validated computation of physiologic flow in a realistic coronary artery branch

Journal Article J. Biomech. (UK) · 1998 The pulsatile flow field in an anatomically realistic model of the bifurcation of the left anterior descending coronary artery (LAD) and its first diagonal branch (D1) was simulated numerically and measured by laser Doppler anemometry. The inlet velocity p ... Full text Link to item Cite

Variability of the planarity of the human aortic bifurcation

Journal Article Medical Engineering & Physics · 1998 The susceptibility of vascular branches to atherosclerosis is believed to be due in part to the unusual fluid dynamic environments that the vessel wall experiences in these regions. As vascular geometry is a primary determinant of the local haemodynamic en ... Full text Link to item Cite

Relation between the structural asymmetry of coronary branch vessels and the angle at their origin

Journal Article J. Biomech. (UK) · 1998 The relationship between the geometry of branch points on the left anterior descending coronary artery, and the morphometry of the proximal portions of the daughter vessels, was examined. The geometry at 23 branch points on 15 human hearts was derived from ... Full text Link to item Cite

Frequency dependence of arterial uptake of macromolecules in response to alternating shear levels

Journal Article American Society of Mechanical Engineers, Bioengineering Division (Publication) BED · 1997 Results are presented of a study on frequency dependence of arterial uptake of macromolecules in response to alternating shear levels. The experiments used an in vivo arteriovenous fistula preparation to modulate the wall shear stress in porcine iliac arte ... Cite

Variability in planarity of the aortic bifurcation measured from magnetic resonance images

Journal Article American Society of Mechanical Engineers, Bioengineering Division (Publication) BED · 1997 The geometry of the aortic bifurcation has drawn attention from several investigators. Notwithstanding the previous studies, the variability of the planarity of the aortic bifurcation has not been well described. This report discusses a study aimed to char ... Cite

Mathematical modelling of blood flow in arterial bifurcations

Journal Article Z. Angew. Math. Mech. (Germany) · 1996 Pulsatile blood flow in anatomically correct models of arterial bifurcations is simulated numerically. The computational geometric models are developed on the basis of optically digitized casts. A finite element grid generation procedure based on optimizat ... Cite

Relation between the structural asymmetry of coronary artery branches and the angle at their origin

Journal Article American Society of Mechanical Engineers, Bioengineering Division (Publication) BED · 1996 The relationship between the geometry of branch points on the left anterior descending coronary artery, and the morphometry of the proximal portions of the daughter vessels, was examined. The geometry at 23 branch points on 15 human hearts was derived from ... Cite

Curvature changes of the left anterior descending coronary artery during the cardiac cycle

Journal Article American Society of Mechanical Engineers, Bioengineering Division (Publication) BED · 1996 A system was developed to track the position and curvature of the human coronary arteries during a cardiac cycle using bi-plane angiography. The system uses a time interpolation technique on one image plane to create simultaneous image pairs. The image pai ... Cite

'Resonant' solute uptake predicted by a model of endothelial permeability dynamics

Journal Article American Society of Mechanical Engineers, Bioengineering Division (Publication) BED · 1995 Generally, the transport of macromolecules across the arterial endothelium, and their subsequent accumulation in the arterial wall is an important factor in the pathogenesis of atherosclerotic disease. It is hypothesized that endothelial permeability rises ... Cite

Correlation of 3-D coronary arterial geometry and histopathology

Journal Article American Society of Mechanical Engineers, Bioengineering Division (Publication) BED · 1995 The localization of atherosclerosis, the progressive thickening and stiffening of arterial vessels is assumed to be influenced by hemodynamic mechanisms. Most hemodynamic mechanisms are influenced by local vascular geometry. Hence, the presence of such geo ... Cite

The effect of pulsatile frequency on wall shear in a compliant cast of a human aortic bifurcation

Journal Article Trans. ASME, J. Biomech. Eng. (USA) · 1995 A realistically compliant flow-through cast of a human aortic bifurcation was perfused with two almost identical physiological flow waves differing in pulsatile frequency. Near-wall fluid velocities were measured with a laser Doppler velocimeter at 14 site ... Cite

Computer simulation of pulsatile flow in an anatomically realistic human left coronary artery bifurcation model

Journal Article American Society of Mechanical Engineers, Bioengineering Division (Publication) BED · 1995 Pulsatile flow and wall shear stress in an anatomically correct model of a human left coronary artery segment is simulated numerically using the finite element method. The computational geometry model presenting a non-planar arterial branching is developed ... Cite

Correlation of in vitro intimal-medial uptake with endothelial shear stress vector fields in an arterial organ support system

Journal Article American Society of Mechanical Engineers, Bioengineering Division (Publication) BED · 1995 Porcine thoracoabdominal intimal surface patterns of transendothelial intimal-medial Evans blue dye-albumin (EBD-albumin) uptake were correlated with experimentally-imposed intimal surface shear stress vector fields in the well chambers of an in vitro arte ... Cite

Influence of turning angle on proximal sudanophilia in the daughter vessels at the bifurcation of the human left main coronary artery - initial results

Journal Article American Society of Mechanical Engineers, Bioengineering Division (Publication) BED · 1995 Rigid injection cast of the left coronary arteries were photographed at multiple angles to provide images of the entire left main (LM), proximal portions of the left anterior descending (LAD) and the left circumflex (LCX) coronary arteries. Certain geometr ... Cite

Fabrication of vascular replicas from magnetic resonance images

Journal Article Trans. ASME, J. Biomech. Eng. (USA) · 1995 Image processing and computer numerical controlled (CNC) machining techniques have been used to prepare a larger-than-life investment cast of an aortic bifurcation from magnetic resonance images of a replica of the vessel. The technique will facilitate exp ... Cite

Calculation of 3-D, pulsatile velocity fields and endothelial shear stress distributions in and arterial organ support system and validation by LDA

Journal Article American Society of Mechanical Engineers, Bioengineering Division (Publication) BED · 1994 The 3-D, steady and pulsatile velocity fields and the corresponding endothelial shear stress fields that are created by a flow applicator in an organ support system have been calculated on a Cray Y-MP8/864 supercomputer using Version 4.2.3 of FLUENT, a com ... Cite

Variability of human coronary artery geometry: an angiographic study of the left anterior descending arteries of 30 autopsy hearts

Journal Article Ann. Biomed. Eng. (USA) · 1994 A computer-based system is described to measure objectively the geometric parameters of arteries from pairs of projection angiograms. This technique, which employs back-projection to define the vessel axes in 3-D space, was used to obtain selected paramete ... Cite

Finite element grid generation in computational arterial blood flow dynamics

Journal Article American Society of Mechanical Engineers, Bioengineering Division (Publication) BED · 1994 A finite element grid generation procedure based on optimization of local grid properties has been developed using anatomically realistic data. The generator is especially suited in modeling of arterial bifurcation flow. The numerical procedure is applied ... Cite

Measurement of the geometric parameters of the aortic bifurcation from magnetic resonance images

Journal Article Ann. Biomed. Eng. (USA) · 1994 Presents a method for measuring arterial geometry in vivo using MRI. The approach was validated using MR images of three perfused compliant casts of human aortic bifurcations whose geometry was known. Preliminary human studies demonstrated the reproducibil ... Cite

Effects of age, race and gender on the geometry of the aortic bifurcation as derived from magnetic resonance images

Journal Article American Society of Mechanical Engineers, Bioengineering Division (Publication) BED · 1993 This paper presents a method of measuring alterral geometry in vivo using MRI. The approach was validated using MR images of three perfused complaint casts of human aortic bifurcations whose geometry was known. Preliminary human studies demonstrated the re ... Cite

Black-blood steady-state magnetic resonance angiography

Journal Article American Society of Mechanical Engineers, Bioengineering Division (Publication) BED · 1993 This paper evaluates steady-state Magnetic Resonance Imaging as a method to generate images depicting flow with low signal intensity for a wide range of velocities. Sixty or twenty eight cross-sectional images with 0.7-1 mm in-plane resolution were obtaine ... Cite

Compact lattice QED and the Coulomb potential

Journal Article Phys. Lett. B (Netherlands) · 1993 The potential energy of a static charge distribution on a lattice is rigorously computed in the standard compact quantum electrodynamic model. The method used follows closely that of Weyl for ordinary quantum electrodynamics in continuous spacetime. The po ... Full text Link to item Cite

Arteriosclerosis research using vascular flow models: from 2-D branches to compliant replicas

Journal Article Trans. ASME, J. Biomech. Eng. (USA) · 1993 Vascular flow models have been used more than any other means to gain insight into the details of arterial hemodynamics. The first flow models were not very realistic. The author's first attempt, was probably the most unrealistic of all: a “2D branch ... Cite

Effects of arterial compliance and non-Newtonian rheology on correlations between intimal thickness and wall shear

Journal Article Trans. ASME, J. Biomech. Eng. (USA) · 1992 A minimally diseased (mean intimal thickness=56 μm) human aortic bifurcation was replicated in rigid and compliant flow-through casts. Both casts were perfused with physiological flow waves having the same Reynolds and unsteadiness numbers; the pulse pr ... Cite

Evaluation of the capabilities of a steerable ultrasound Doppler catheter to provide quantitative coronary flow indices

Journal Article American Society of Mechanical Engineers, Bioengineering Division (Publication) BED · 1992 A compliant flow-through coronary cast and an in-vitro coronary flow system with physiologic flow were developed to evaluate, by comparison with laser Doppler anemometry (LDA), the capability of a 3F Millar steerable ultrasound Doppler catheter to provide ... Cite

The effect of compliance on wall shear in casts of a human aortic bifurcation

Journal Article Trans. ASME, J. Biomech. Eng. (USA) · 1990 Rigid and complaint casts of a human aortic bifurcation were subjected to physiologically realistic pulsatile fluid flows. At a number of sites near the wall in the approximate median plane of the bifurcation of these models, fluid velocity was measured wi ... Cite

Effect of pulsatile frequency on wall shear in a compliant cast of a human aortic bifurcation

Journal Article American Society of Mechanical Engineers, Bioengineering Division (Publication) BED · 1990 A realistically compliant flow-through cast of a human aortic bifurcation was perfused with two almost identical physiological flow waves differing in pulsatile frequency. Near-wall fluid velocities were measured with a laser Doppler velocimeter at 14 wall ... Cite

Variations in geometry and shear rate distribution in casts of human aortic bifurcations

Journal Article J. Biomech. (UK) · 1989 Shear rates measured at sites along the walls of ten casts of human aortic bifurcations are presented to provide an indication of the variability in the shear rate distribution that can occur among individuals. The geometric characteristics and flow parame ... Cite

Effect of compliance on wall shear in casts of a human aortic bifurcation

Journal Article American Society of Mechanical Engineers, Bioengineering Division (Publication) BED · 1988 Rigid and compliant casts of a human aortic bifurcation were subjected to physiologically realistic pulsatile fluid flows. At a number of sites near the wall in the plane of the bifurcation of these models, fluid velocity was measured with a laser Doppler ... Cite

Correlation among shear rate measures in vascular flows

Journal Article Trans. ASME, J. Biomech. Eng. (USA) · 1987 A variety of shear rate measures have been calculated from haemodynamic data obtained by laser Doppler anemometry in flow-through casts of human aortic bifurcations. Included are measures sensitive to the mean and amplitude of the shear rate, its maximum r ... Cite

3-D RECONSTRUCTION OF CORONARY ARTERY MEDIAL AXES FROM BI-PLANE ANGIOGRAPHY.

Journal Article Computers in Cardiology · 1987 A technique has been developed to provide a 3-D, quantitative reconstruction of the coronary tree using axes extracted from two angiograms acquired at different angles. The reconstructed axes may be viewed from any perspective, even those normally unattain ... Cite

Surface Hall effect in magneto-electric media

Journal Article J. Phys. A, Math. Gen. (UK) · 1986 The nature of the bulk energy per unit volume in magneto-electric crystals implies an unusual form of Hall effect confined to the boundary surface crystal faces ... Full text Link to item Cite

Measurement of wall motion and wall shear in a compliant arterial cast

Journal Article Trans. ASME, J. Biomech. Eng. (USA) · 1986 Initial measurements of the time-varying wall shear rate at two sites in a compliant cast of a human aortic bifurcation are presented. The shear rates were derived from flow velocities measured by laser Doppler velocimetry (LDV) near the moving walls of th ... Cite

Quantization of the magnetic induction for two-dimensional electronic systems

Journal Article Phys. Rev. B, Condens. Matter (USA) · 1985 In previous work, the concept of a quantized vortex was used to model the rational quantization of the Hall conductance for two-dimensional electronic systems. Here it is shown how the vortex model directly implies the concept of quantized magnetic inducti ... Full text Link to item Cite

Nonquasi-steady character of pulsatile flow in human coronary arteries

Journal Article Trans. ASME, J. Biomech. Eng. (USA) · 1985 This experiment was conducted to determine if the pulsatile flow through the proximal portion of the left coronary artery system in man exhibits quasi-steady characteristics. Steady and pulsatile flows were passed through an idealized model whose dimension ... Cite

Engineering the chiral anomaly: the quantum Hall effect

Journal Article Lett. Nuovo Cimento (Italy) · 1985 Some practical aspects of the chiral anomaly present in quantum electrodynamics are discussed in connection with the fractional Hall effect. The possibility that certain instabilities may develop is pointed out ... Cite

HEMODYNAMIC MEASUREMENTS OF PULSATILE FLOW THROUGH A COMPLIANT CAST OF A HUMAN AORTIC BIFURCATION.

Journal Article Advances in Bioengineering · 1985 This paper reports on a preliminary investigation that was carried out to develop experimental techniques which would enable the measurement of flow velocities in compliant arterial casts whose walls are in motion. A cast was made of an aortic bifurcation ... Cite

Implications of the chiral anomaly for quantum Hall-effect devices

Journal Article Phys. Rev. B, Condens. Matter (USA) · 1985 The anomaly equation ∂μJ5μ=-(e2/8π2ℏ2c) (F*λσFλσ) is used to derive a relationship between the filling factor (ν) and the Hall conductance on the gate capacitor of a field-effect-transistor device. In addit ... Full text Link to item Cite

Microchips as precision quantum-electrodynamic probes

Journal Article Phys. Rev. Lett. (USA) · 1985 The authors show that QED fluctuations for present metal-oxide-semiconductor field-effect transistor microcircuit devices are substantial and thus cannot be ignored. For example, the Casimir energy of a gate-region capacitor is typically 1/10 of the electr ... Full text Link to item Cite

Vacuum spin waves through the chiral anomaly

Journal Article Phys. Lett. A (Netherlands) · 1985 It is shown that the quantum electrodynamic chiral anomaly generates `spin waves' in the vacuum, when a low-energy electromagnetic field is applied. Such spin waves are (in principle) observable in a vacuum region with a condensed matter boundary surface w ... Full text Link to item Cite

Computational aspects of aortic bifurcation flows

Journal Article Comput. Fluids (UK) · 1985 The authors' investigation of bifurcation flows is extended to two-dimensional regions obtained from radiographs of human aortic bifurcations. These regions were mapped onto rectangles with a slit. Wall shapes were at first approximated using cubic splines ... Full text Link to item Cite

Unsteady transport and hydration dynamics in the in vivo cornea

Journal Article Biophys. J. (USA) · 1985 The unsteady response of the rabbit cornea to the normal periodic variations in tear tonicity which accompany the sleep-wake cycle is examined quantitatively in terms of a physical description of corneal mechanics and transport. Two different sets of exper ... Cite

Changes in aortic bifurcation geometry during a cardiac cycle

Journal Article J. Biomech. (UK) · 1984 In vivo radial strain measurements at the rabbit aortic bifurcation were made at different times during the cardiac cycle. At the peak of the pressure pulse, the radial strain at the bifurcation is positive in the plane perpendicular to the bifurcation but ... Full text Link to item Cite

Chiral anomaly and the rational quantization of the Hall conductance

Journal Article Phys. Rev. Lett. (USA) · 1984 The quantum Hall effect is shown to be equivalent to a chiral anomaly i quantum electrodynamics. The integers n1 and n2 in the rationally quantized Hall conductance g=(e2/2πℏ)(n1/n2) arise from vortex excitations carrying n1 electrons and n2 flux ... Full text Link to item Cite

Magnetic flux of `vortices' on the two-dimensional Hall surface [and reply]

Journal Article Phys. Rev. Lett. (USA) · 1984 Friedman et al. (see ibid, vol.52, p.1587 (1984)) proposed a model for the QHE involving the flow of charged vortices which carried a magnetic flux due to the Hall current generated by the electric field of the charge e*. They treated the electromagnetic f ... Full text Link to item Cite

Numerical simulation of aortic bifurcation flows: the effect of flow divider curvature

Journal Article J. Biomech. (UK) · 1984 Two dimensional steady flow calculations in computational regions obtained from radiographs of human aortic bifurcations correlate well with unsteady measurements of wall shear in flow-through casts of the same vessels. The results suggests that wall slope ... Full text Link to item Cite

Comparison of steady and pulsatile flow near the ventral and dorsal walls of casts of human aortic bifurcations

Journal Article Trans. ASME, J. Biomech. Eng. (USA) · 1984 Steady and pulsatile flows were passed through casts of human aortic bifurcations and, by means of a laser Doppler anemometer, fluid velocities were measured at selected sites near the ventral and dorsal walls. At these sites, in the vicinity of the bifurc ... Cite

GEOMETRIC RISK FACTORS FOR ARTERIOSCLEROSIS.

Journal Article Johns Hopkins APL Technical Digest (Applied Physics Laboratory) · 1983 It has been known for some time that the rate of developement of cardiovascular disease varies among individuals. It is proposed that some of this unexplained variability is due to corresponding variations in the detailed geometry of susceptible arterial s ... Cite

Calculations of q2q¯2 states in potential theory

Journal Article Phys. Rev. D, Part. Fields (USA) · 1983 A model proposed by Aaron and Friedman (1982) is used to study q2q¯2 states. The results lead to speculations concerning the nature of the ε(1300) ... Full text Link to item Cite

Fundamentals of ion motion in electric radio-frequency multipole fields

Journal Article J. Phys. E, Sci. Instrum. (UK) · 1982 The fundamentals of ion motion in electromagnetic fields are reviewed in detail with a special emphasis on electric radio-frequency (RF) fields which are used frequently in dynamic mass spectrometry. Forces and effects on ions in electromagnetic fields whi ... Full text Link to item Cite

The inverted pendulum: a mechanical analog of the quadrupole mass filter

Journal Article Am. J. Phys. (USA) · 1982 The inverted pendulum is shown to be an analog of the quadrupole mass filter. The theory of the inverted pendulum is developed and the design criteria for a working model are presented. The working model is used to experimentally measure the β paramet ... Cite

TRACER PERMEABILITIES UNDERESTIMATE TRANSMEMBRANE SOLUTE FLUX UNDER A CONCENTRATION GRADIENT.

Journal Article Journal of Membrane Science · 1981 The measured flux of sucrose across Cuprophan dialysis membrane in the presence of a concentration gradient is significantly greater than the flux predicted from radioactive tracer permeabilities measured in the absence of a concentration gradient. The dif ... Full text Link to item Cite

Transport across homoporous and heteroporous membranes in nonideal, nondilute solutions. I. Inequality of reflection coefficients for volume flow and solute flow

Journal Article Biophys. J. (USA) · 1981 The Kirkwood formulation of the Stefan-Maxwell equations is used to develop the transport equations for a membrane bounded by nonideal, nondilute solutions. The reflection coefficients for volume flow and solute flow are not equal but are related by a simp ... Cite

Correlation of human arterial morphology with hemodynamic measurements in arterial casts

Journal Article Trans. ASME, J. Biomech. Eng. (USA) · 1981 A realistic pulsatile flow was passed through a cast of the aortic bifurcation of a 63-yr-old male with mild artherosclerosis, and a laser Doppler anemometer was used to measure fluid velocities in the cast at 15 selected sites near the lateral and medial ... Cite

Transport across homoporous and heteroporous membranes in nonideal, nondilute solutions. II. Inequality of phenomenological and tracer solute permeabilities

Journal Article Biophys. J. (USA) · 1981 For pt.I see ibid., vol.34, p.535, 1981. The phenomenological solute permeability (ωp) of a membrane measures the flux of solute across it when the concentrations of the solutions on the two sides of the membrane differ. The relationship between &ome ... Cite

Hemodynamic measurements in human arterial casts, and their correlation with histology and luminal area

Journal Article Trans. ASME, J. Biomech. Eng. (USA) · 1980 A new approach is presented for studying the vascular response to hemodynamic stress. A laser doppler anemometer is used to make velocity measurements very near the walls of human arterial casts; these measurements are then correlated with the histology of ... Cite

Simple Lagrangian for a superspace affine theory

Journal Article Phys. Rev. D, Part. Fields (USA) · 1980 Arguments are advanced for considering a particular Lagrangian in superspace. It is constructed solely from the connection associated with the graded group of real, general linear transformations, and is especially simple in form. The resulting equations o ... Full text Link to item Cite

Simple directionally sensitive two-component laser Doppler anemometer

Journal Article Appl. Opt. (USA) · 1980 An additional modification is presented that allows velocity components to be measured in any direction in the plane perpendicular to the optical axis of the system. This is done by revolving the axis of the diffraction grating about the laser beam. The di ... Cite

HEMODYNAMIC MEASUREMENTS IN HUMAN ARTERIAL CASTS: GEOMETRIC EFFECTS AND MORPHOLOGICAL CORRELATES.

Journal Article American Society of Mechanical Engineers, Applied Mechanics Division, AMD · 1979 The distribution of atherosclerotic lesions in the large arteries strongly suggests that blood flow patterns (hemodynamics) adjacent to the vessel wall play a role in the development of the disease. The authors' approach has been to make hemodynamic measur ... Cite

Hypophysectomy-induced inhibition of augmented acetycholine responses of the rat bowel following adrenalectomy and/or whole body irradiation

Journal Article Radiat. Environ. Biophys. (West Germany) · 1979 Functional changes in the intestinal responsiveness to a fixed dose of acetylcholine were studied in muscle strips removed from young adult male rats previously exposed to whole body gamma radiation. In the irradiated rat the responsiveness to a fixed dose ... Cite

Einstein equations, supersymmetry, and flat limits of curved superspace

Journal Article Phys. Rev. D, Part. Fields (USA) · 1978 An affine theory of unified interactions is reviewed. Einstein's free gravitational equation emerges as a special case of the proposed equations of motion on superspace. For this example the vacuum is spontaneously broken to be globally Lorentz invariant. ... Full text Link to item Cite

A computer language for reducing activation analysis data

Journal Article J. Radioanal. Chem. (Switzerland) · 1978 A program, written in FORTRAN, is described that defines a language MULTELMT for reducing activation analysis data. Communications are effected through commands, and these can be given in almost any order. Consistency checks are done and diagnostic message ... Cite

Flexibility in the reduction of activation analysis data: MULTELMT

Journal Article Trans. Am. Nucl. Soc. (USA) · 1978 The main design features of MULTELMT (a computer language mnemonic: MULTiple ELeMenT), with emphasis on features not previously described. This language is written in FORTRAN V and is a translator rather than a compiler. Other analysts should find this lan ... Cite

Allowed supersymmetric vacuums

Journal Article Phys. Rev. D, Part. Fields (USA) · 1977 Constructs the vacuum connection associated with a Yang-Mills theory of the graded Lie group of real linear transformations on superspace and discusses the obtained supersymmetric vacua. Shows that many of them lead to noninvertible vacuum metrics and/or t ... Full text Link to item Cite

STEADY CONVECTIVE DIFFUSION IN A BIFURCATION.

Journal Article IEEE Transactions on Biomedical Engineering · 1977 In a study of the development of atherosclerotic lesions, the authors investigate convective diffusion along the wall of a modeled arterial bifurcation. Under boundary layer assumptions, the resulting set of equations is transformed into a form to which La ... Cite

EXPERIMENTAL INVESTIGATIONS OF STEADY AND PULSATILE LAMINAR FLOW IN A 90 degree BRANCH.

Journal Article Journal of Applied Mechanics, Transactions ASME · 1977 Velocity measurements are reported for steady and unsteady flow in a rectangular cross-section Y-branch of high aspect ratio. Good agreement is found between the experimental results and two-dimensional calculations. Emphasis is placed on flow velocities n ... Cite

Yang-Mills gauge invariance on a space of Bose and Fermi coordinates

Journal Article Phys. Rev. D, Part. Fields (USA) · 1977 Develops a formalism for imposing on superspace Yang-Mills local gauge invariance induced by general coordinate transformations. Shows that the construction of derivatives forces the introduction of a connection which is expected to be a function of all th ... Full text Link to item Cite

Particle paths and stasis in unsteady flow through a bifurcation

Journal Article J. Biomech. (UK) · 1977 In a study of the role of fluid mechanics in atherogenesis particle paths and stasis in a two-dimensional symmetric branch were examined, using the results of earlier fluid mechanical simulations of pulsatile blood flow to provide the velocity field. In re ... Full text Link to item Cite

Steady convective diffusion in a bifurcation [arterial flow]

Journal Article IEEE Trans. Biomed. Eng. (USA) · 1977 In a study of the development of atherosclerotic lesions, the authors investigate convective diffusion along the wall of a modelled arterial bifurcation. Under boundary layer assumptions, the resulting set of equations is transformed into a form to which L ... Cite

Interferrometric technique for the simultaneous measurement of passive membrane transport coefficients

Journal Article Rev. Sci. Instrum. (USA) · 1977 A laser interferrometric technique has been used to follow the concentration difference across a membrane separating two fluid chambers. A constant pressure head is maintained across the membrane. The fluid volume in one chamber is monitored by measuring t ... Full text Link to item Cite

Transport through a growing boundary layer to a permeable wall

Journal Article AIChE J. (USA) · 1976 The author discusses the flow past a surface which is permeable to the solute, when the interface boundary condition is complex and the variation along the wall of interfacial concentration or flux must in general be found by iterative numerical techniques ... Full text Link to item Cite

Unsteady flow in a branch

Journal Article J. Fluid Mech. (UK) · 1976 This study was motivated by the focal tendency of atherosclerotic plaque to appear near arterial junctions. A two-dimensional bifurcation was selected to provide preliminary information on branch flow dynamics. Superceding previous steady flow estimates in ... Cite

Weak currents in an internal parity model

Journal Article Phys. Lett. B (Netherlands) · 1976 The suggestion that there exists an `internal parity' carried by the electron and μ-meson which is multiplicatively conserved is incorporated into a spontaneously broken gauge theory of the weak and electromagnetic interactions. The inclusion of hadrons ... Full text Link to item Cite

A computerized bibliographic service for the blind and physically handicapped

Journal Article J. Libr. Autom. (USA) · 1975 In 1897, as a special service to the blind, the Library of Congress established a small reading room stocked with approximately 500 books and music items in raised type. In 1974, a comprehensive internal study was begun by the Library of Congress Division ... Cite

Case study in successful library computerization

Journal Article Spec. Libr. (USA) · 1975 The US Environmental Protection Agency's National Environmental Research Center in Cincinnati, Ohio, has set up a computerized service system following low-cost guidelines. The collection's catalog has been taped and literature searches are now available a ... Cite

Calculations of pulsatile flow through a branch: implications for the hemodynamics of atherogenesis

Journal Article Circ. Res. (USA) · 1975 Numerical simulations of pulsatile blood flow through a symmetrical branch modeling the aortic bifurcation were carried out to assess several hemodynamic variables with that of early lesions in arterial branches. All of the proposed hemodynamic promoters o ... Cite

Effect of spatial variations in shear on diffusion at the wall of an arterial branch

Journal Article Circ. Res. (USA) · 1975 The effect of spatially varying shear on transport to the wall of a two-dimensional branch was examined, using oxygen as the test solute and the results of earlier fluid mechanical calculations to provide the shear profiles in a region characterizing the a ... Cite

EXPERIMENTAL INVESTIGATION OF LAMINAR FLOW IN A RECTANGULAR CROSS-SECTION BIFURCATION.

Journal Article American Society of Mechanical Engineers, Applied Mechanics Division, AMD · 1975 The geometry and flow parameters of this experiment are chosen for this parallel plate model to be comparable to the hemodynamic situation in the human terminal abdominal aorta. Thus the experimental Reynolds numbers, based on channel half-width and the av ... Cite

Gauge invariance of gravitational theory

Journal Article Phys. Rev. D, Part. Fields (USA) · 1975 The invariance of the gravitational theory of Einstein under general coordinate transformations was demonstrated to be equivalent to invariance under local gauge transformations of the group GL(4,R) by Yang (see Phys. Rev. Lett., vol.33, p.445 (1974)). Thi ... Full text Link to item Cite

Light-cone algebra, field-current identity, and deep-inelastic scattering

Journal Article Phys. Rev. D, Part. Fields (USA) · 1973 The authors reproduce the full content of the Fritzsch-Gell-Mann light-cone algebra (originally derived using the quark model) for deep-inelastic lepton-nucleon scattering using currents given by the field-current identity. These currents are modified by d ... Full text Link to item Cite

Thickness control in the living cornea

Journal Article APL Tech. Dig. (USA) · 1972 The mechanisms by which the normal cornea maintains its thickness and hence its transparency in vivo are elucidated by an unsteady-state description of corneal mass transport. All modes of transport, diffusion and convection of solute, hydraulic and osmoti ... Cite

Currents, colliding beams and the light cone

Journal Article Phys. Lett. B (Netherlands) · 1972 Currents of scale dimension 3 of the field-current identity type arise naturally from the principles of broken scale invariance. Applications at intermediate energy to e++e- annihilation into four charged pions, and at high energy to light cone commutators ... Cite

N-point functions in chiral SU(3)xSU(3) current algebra

Journal Article Phys. Rev. D, Part. Fields (USA) · 1971 Hard-meson techniques are presented for calculating processes involving octets (nonets) of mesons under the assumptions of chiral SU(3)×SU(3) [U(3)×U(3)] current-algebra commutation relations, partial conservation of axial-vector current, conse ... Full text Link to item Cite

Spin-zero pole dominance in the weak and electromagnetic interactions of the K-meson

Journal Article Nuovo Cimento A (Italy) · 1971 The assumption of π, η and σ dominance of the weak and electromagnetic decays of the K-meson is examined using the hard- meson current algebra amplitudes for the strong-interaction factors. The K→3π decay spectrum, the KL0→2&gamma ... Cite

Chiral algebra, chiral breakdown, and ξ parameter of kl3 decay

Journal Article Phys. Rev. Lett. (USA) · 1971 Using hard-meson current algebra with single meson dominance of currents and the σ commutator, it is deduced that the 0± mesons must occur in nonets, and chiral symmetry is broken by only (3,3*)⊕(3*,3) terms (which then implies a small & ... Full text Link to item Cite

A Lagrangian approach to dual pion amplitudes

Journal Article Nucl. Phys. B (Netherlands) · 1971 A simple Lagrangian is constructed, which in the tree approximation produces a ππ scattering amplitude possessing (i) the correct iso-spin structure with no exotic resonances (ii) Regge asymptotic behavior Sαρ(t) and (iii) duality and satis ... Cite

Application of computer experimentation to the cornea

Journal Article Nature (UK) · 1971 A computer model of the cornea has been used to examine the implications of measurements of the variation of the short-circuit current of the isolated rabbit cornea as the sodium content of the media bathing both the epithelial and endothelial surfaces is ... Cite

Broken scale invariance, current algebra, and massive `gravitation. I. General formulation

Journal Article Phys. Rev. D, Part. Fields (USA) · 1971 A general analysis is given of the interaction of mesons of JP=0±, 1±, and 2+ obeying the principles of broken scale invariance in the tree and seagull approximations. Broken scale invariance is introduced through a new postulate which requir ... Full text Link to item Cite

Veneziano amplitude, current algebra, and vertex functions

Journal Article Phys. Rev. D, Part. Fields (USA) · 1970 The possibility is examined of extending the ππ→ππ and πA1→ππ Veneziano amplitudes to the case of one or two mesons off the mass shell in a fashion consistent with chiral current algebra, partial conservation of axial-vector ... Full text Link to item Cite

Amplitudes with Mandelstam analyticity and dual structure

Journal Article Phys. Rev. Lett. (USA) · 1970 A general representation for scattering amplitudes is proposed which is crossing symmetric, satisfies Regge behaviour and duality, and possesses double spectral functions. As the width parameter goes to zero, the resonance poles on the second sheet move on ... Full text Link to item Cite

Field-current identity, partially conserved currents, and the Veneziano model

Journal Article Phys. Rev. Lett. (USA) · 1969 Hard-meson partial conservations of axial-vector and partial conservation of vector current are imposed upon the Veneziano amplitudes. It is seen that these determine inelastic amplitudes (e.g., ππ→πA1, etc.) in terms of corresponding elastic ... Full text Link to item Cite

Hard-meson current algebra analysis of the Kl3 decay

Journal Article Nucl. Phys. B (Netherlands) · 1969 A hard-meson calculation of the Kl3, K* and κ decays is given based upon (i) chiral SU(3)×SU(3) current algebra, (ii) pion and kaon PCAC, (iii) single meson saturation, (iv) approximation of meson vertices by low-order polynomials in momentum ... Cite

A general thermal explosion criterion application to initiation by imbedded wires

Journal Article Combust. Flame (USA) · 1969 A thermal explosion criterion recently published by the author (see ibid., vol.11, 239 of 1967) is used to obtain general solutions for the explosion/ignition delay of an exothermic material surrounding a heated wire which is long and a good thermal conduc ... Cite

Application of hard-pion four-point functions to pion-pion scattering

Journal Article Phys. Rev. (USA) · 1968 Application of hard-pion four-point functions is made to ππ scattering on the basis of the SU(2)×SU(2) current algebra, a conserved vector current, a partially conserved axial-vector current, and the hypothesis of single-meson dominance of inte ... Cite

On chiral algebra, meson dominance and the soft-pion evaluation of gρ

Journal Article Nuclear Physics · 1968 The derivations of gρ2 = 2Fπ2mρ2 by Kawarabayashi and Suzuki (Abstr. 1966A26144) and others are re-examined. When the full content of chiral algebra is exploited, the analysis reduces to an identity rather than a determination of gρ. (15 Ref ... Cite

Hard-pion current-algebra calculations of meson processes-N-point functions

Journal Article Phys. Rev. (USA) · 1968 Hard-pion techniques are presented for calculating T products of an arbitrary number of vector and axial-vector currents under the assumptions of single σ-.π-,ρ-, and A1 meson saturation of intermediate sums, chiral SU(2)×SU (2)-algebra ... Cite

Hard-pion current-algebra calculation of meson processes-three-point functions

Journal Article Phys. Rev. (USA) · 1968 Hard-pion techniques are presented for calculating vertex functions involving π,ρ,A1, and σ mesons. The development of the method involves the following assumptions: (a) saturation of intermediate sums by single mesons, (b) chiral SU(2)× ... Cite

Hard-pion calculation of π-π scattering

Journal Article Physical Review Letters · 1968 A mass-shell current-algebra calculation of π-π scattering is given. The Weinberg scattering lengths and effective ranges are shown to be valid within a few percent. At the K meson mass, we find the essentially model-independent result δ0-&delt ... Full text Link to item Cite

Application of hard-pion three-point functions

Journal Article Phys. Rev. (USA) · 1968 Some comparisons with experiment of the hard-pion three- point functions obtained from SU(2)×SU(2) current algebra are given. Available experimental data involving π,ρ, A1, and σ mesons are examined. The hard-pion current-algebra method ... Cite

Current algebra and vertex functions

Journal Article Physical Review Letters · 1967 A method is given for calculating vertex functions involving three currents obeying chiral SU(2) ⊗ SU(2) commutation relations, without using soft-pion approximations. The procedure assumes one-particle dominance of intermediate states. The Weinberg ... Full text Link to item Cite

Approach to the bound-state three-body problem with application to the helium-like atom

Journal Article Physical Review · 1967 A technique is presented for treating a general type of three-body bound-state problem for situations where the interaction may be written as the sum of three pair potentials. The method is based on the work of Eyges and consists of writing the total wave ... Full text Link to item Cite

Generalized thermal explosion criterion-exposition and illustrative applications

Journal Article Combustion and Flame · 1967 Generalized thermal explosion criterion is presented, based on inert and adiabatic solutions to sensitivity equation; algorithm can be used to find critical conditions and explosion delays for many thermal explosion problems; technique is applied in illust ... Full text Link to item Cite

Approximate closed solutions for detonation parameters in condensed explosives

Journal Article AIAA Journal · 1966 Virial equation of state is used to derive solutions for detonation velocity and pressure of explosives; detonation parameters are defined by energy of detonation, loading density, average number of atoms per gaseous product molecule, weight fraction solid ... Cite

Shock tube measurement of explosive sensitivity

Journal Article Combustion and Flame · 1966 A shock tube test is described, in which fine dusts or sprays of explosive materials are ignited behind the reflected shock, and the dependence of the measured ignition delay on reflected shock temperature is determined. The test simulates the impact initi ... Full text Link to item Cite

Shock tube measurement of explosive sensitivity

Journal Article Combustion Institute -- Paper · 1965 Shock tube test is described in which fine dusts or sprays of explosive materials are ignited behind reflected shock, and dependence of measured ignition delay on reflected shock temperature is determined; test simulates impact initiation of liquids and so ... Cite

A variational procedure for the statistical mechanics of a many-boson system

Journal Article Nuovo Cimento B · 1965 A variational procedure due to Husimi (1940) is applied to the many-boson problem in an effort to find an approximate density matrix. The results are identical to those previously obtained by Wentzel (1960) employing another technique. It differs primarily ... Cite

Energy spectrum of a simple Bose-Eeinsten model

Journal Article Physical Review · 1965 A soluble model of a Bose - Einstein system is examined, in which the interaction energy between particles is attractive as the momentum approaches zero. The model is based on one proposed by Bassichis and Foldy. ... Full text Link to item Cite

Size of "hot spots" in impact explosion of exothermic materials

Journal Article Faraday Society -- Transactions · 1963 Research based on work relating to solid propellants; hot spot is represented by mathematical model as rectangular temperature spike in infinitely large sample of reactant; consequent differential equation is integrated numerically and results are correlat ... Cite

Prediction of detonation characteristics of condensed explosives

Journal Article American Chemical Society -- Division of Fuel Chemistry -- Papers · 1963 Method of predicting Chapman-Jouguet detonation characteristics, has been developed; gaseous explosion products are assumed to obey virial equation of state; analysis predicts detonation pressure as well as, or better than, solutions based on Abel or Kisti ... Cite

Flame failure system switches boiler auxiliaries to steam operation

Journal Article Heating, Piping and Air Conditioning · 1959 Protective system at US Military Academy, West Point, NY, which is not affected by power failures; system consists of separate scanner for each burner which operates through control panel to close individual fuel valve, light its respective pilot and sound ... Cite

μ-Meson decay and the two-component neutrino

Journal Article Physical Review · 1957 Remarks that the experimental values of the Michel parameter (ρ) and the back - front (B/F) ratio for decay electrons between 0 and 10 MeV seem inconsistent with predictions of the two-component theory assuming the decay process: μ→ e+ν+ν ... Cite

Theory of S-wave pion scattering and photo-production at low energies

Journal Article Physical Review · 1956 A fixed-source analysis of the s-wave pion -nucleon interaction is constructed along the lines of the Chew-Low-Wick formalism. A bilinear s-wave interaction of the form λ0φ.φ+λτ.(φ×pi;) is added to the usual p-wave coupl ... Cite

Scattering of pions by nucleons in intermediate coupling

Journal Article Physical Review · 1955 An intermediate-coupling method of calculation is applied to the meson-nucleon scattering problem for the case of symmetric pseudoscalar mesons, coupled to a fixed extended source through derivative coupling. It is found that the experimentally observed P- ... Cite

A system for the automated acquisition and reduction of neutron activation analysis data

Journal Article Trans. Am. Nucl. Soc. (USA) · 1955 A system is described, based on a multiple element language MTELMT which can automatically search a spectrum, find the resolved peaks, and output the energies and areas of the peaks; make linear or semilogarithmic CAL COMP plots; and provide an accurate en ... Cite

Anomalous magnetic moment of the nucleon

Journal Article Physical Review · 1955 The ground-state solution of the physical nucleon problem in the Tomonaga approximation is used to compute the anomalous magnetic moment of nucleons. When computed on the basis of parameters that make the phase-shift calculations in the Tomonaga approximat ... Cite

Nucleon anomalous moment in a cut-off meson theory

Journal Article Physical Review · 1955 The anomalous magnetic moments of the neutron and proton are calculated to fourth order by using a cut-off meson theory. The value obtained is 1.44 when one uses the same parameters as employed for fitting the meson-nucleon scattering data. ... Cite

Partition function for a system of interacting Bose-Einstein particles

Journal Article Physical Review · 1955 It is shown by a rigorous development from first principles that a relatively simple form for the partition function of an imperfect Bose-Einstein gas can be obtained. This form is that of a 3N-dimensional integral (N being the total number of particles) t ... Cite

Gauge theories with composite bosons

Journal Article Phys. Rev. D, Part. Fields (USA) The authors develop an approach for introducing bosons into gauge theories as composite states of fermions. It is scale and gauge invariant from the outset and utilizes invariant regularization procedures. This results in the acquisition of gauge-covariant ... Full text Link to item Cite

Fermions in an external SU(2) magnetic field

Journal Article J. Phys. G, Nucl. Part. Phys. (UK) We consider fermions in a constant and uniform external SU(2) magnetic field. We find that the results for the energy levels depend on the choice of gauge. Choosing a Landau-type gauge yields results analagous to those of Abelian theories. On the other han ... Full text Link to item Cite

The physical states of QCD

Journal Article Phys. Essays (Canada) We use the constraint imposed by Gauss's law to argue that the color charged states of SU(3) [quantum chromodynamics (QCD)] are not physical. We further show that the matrix elements of products of gluon field and quark current operators at different space ... Cite