Permeability of concrete is commonly used as a key index for assessing the durability of concrete, especially when concrete is to be exposed to the aggressive environment. For a porous material like concrete, permeability depends on porosity and pore characteristics such as pore size, orientation, connectivity, and size variation. The effects of porosity and pore characteristics on permeability...

OBJECTIVE To examine the association between cardiovascular risk factors and retinal arteriolar tortuosity in a multi-ethnic child population. METHODS AND RESULTS Cross sectional study of 986 UK primary school children of South Asian, black African Caribbean, and white European origin aged 10 to 11 years. Anthropometric measurements and retinal imaging were carried out and a fasting blood sam...

A 44-year-old woman who showed recurrent vitreous hemorrhages with vascular tortuosity received CT angiography which revealed an internal carotid artery aneurysm. A case of internal carotid aneurysm was associated with a pattern of retinal arteriolar tortuosity pathognomic for familial retinal arterial tortuosity (fRAT), suggesting possible involvement of the cerebral circulation. We present a ...

PURPOSE To determine, with novel software, the feasibility of measuring the tortuosity and width of retinal veins and arteries from digital retinal images of infants at risk of retinopathy of prematurity (ROP). METHODS The Computer-Aided Image Analysis of the Retina (CAIAR) program was developed to enable semiautomatic detection of retinal vasculature and measurement of vessel tortuosity and ...

Empirical relationships between effective conductivities in porous and composite materials and their geometric characteristics such as volume fraction ε, tortuosity τ and constrictivity β are established. For this purpose, 43 virtually generated 3D microstructures with varying geometric characteristics are considered. Effective conductivities σeff are determined by numerical transport simulatio...

BACKGROUND AND PURPOSE Arteriopathy is the leading cause of childhood arterial ischemic stroke. Mechanisms are poorly understood but may include inherent abnormalities of arterial structure. Extracranial dissection is associated with connective tissue disorders in adult stroke. Focal cerebral arteriopathy is a common syndrome where pathophysiology is unknown but may include intracranial dissect...

BACKGROUND AND PURPOSE Optic nerve tortuosity is one of several nonmalignant abnormalities documented on MR imaging in patients with neurofibromatosis type 1 and may be related to the development of optic pathway gliomas. This study seeks an operational definition for optic nerve tortuosity. MATERIALS AND METHODS A focus group of 3 pediatric neuroradiologists reviewed 20 MR images of the brai...

PURPOSE To examine the agreement of a novel computer program measuring retinal vessel tortuosity with subjective assessment of tortuosity in school-aged children. METHODS Cross-sectional study of 387 retinal vessels (193 arterioles, 194 veins) from 28 eyes of 14 children (aged 10 years). Retinal digital images were analyzed using the Computer Assisted Image Analysis of the Retina (CAIAR) prog...

OBJECTIVE The purpose of this study was to examine the effect of aortoiliac tortuosity, as assessed by observers and 3-dimensional (3D) computer-based methods, on the conduct and outcome of endovascular repair of abdominal aortic aneurysms. METHODS Infrarenal aortoiliac tortuosity was measured in 75 patients (mean follow-up, 14.8 +/- 10.4 months) who underwent endovascular repair of abdominal...

PURPOSE Plus disease is severely abnormal dilation and tortuosity of posterior retinal blood vessels in infants with retinopathy of prematurity (ROP). It has become the major criterion for laser treatment in ROP, but its assessment is subjective and prone to error. ROPtool is a computer program that traces retinal blood vessels, measures their tortuosity, and determines whether there is suffici...