The structure and transport properties of pit membranes at the interface between the metaxylem and xylem parenchyma cells and the possible role of these pit membranes in solute transfer to the phloem were investigated. Electron microscopy revealed a fibrillar, almost tubular matrix within the pit membrane structure between the xylem vessels and xylem parenchyma of leaf blade bundles in rice (Or...

BACKGROUND High blood pressure causes a change in vascular wall structure involving altered extracellular matrix composition, but how this process occurs is not fully understood. METHODS AND RESULTS Using mouse carotid arteries maintained in organ culture for 3 days, we detected increased gelatin zymographic activity of matrix metalloproteinase (MMP)-2 (168+/-13%, P<0.05) in vessels kept at l...

A problem on the fracture of a thin-walled spherical vessel affected by increasing internal pressure is formulated. The material properties both in stage hardening and softening (prefracture) are described. mathematics catastrophe theory used to write down equilibrium equations find critical value pressure, at which fails.

Much work has already been done on Type IV high-pressure vessels, both from an experimental and numerical point of view. The prediction the maximum pressure before bursting, effect thermal cycles, defect damage tolerance, fire resistance, liner collapse are topics generally numerically studied at scale samples. In these previous works, passage specimen to structure is not fully validated by com...

Vascular malformations are a disruption of the normal vascular pattern in which it is expected that a capillary network of microscopic vessels lies interposed between high-pressure arteries that deliver blood and thin-walled veins that collect low-pressure blood for return to the heart. In the case of arteriovenous malformations, arteries or arterioles connect directly to the venous collection ...

Increasing pulmonary arterial (Ppa) and wedge (Pw) pressures at high flow (Q) during exercise could distend the thin-walled vessels. A mechanical descriptor of vascular distension, the distensibility (alpha, fractional diameter change/mmHg pressure), has been reported to be approximately 0.02 for isolated large and small arteries, i.e., a 2% change in diameter per millimeter mercury pressure. I...

We tested the hypothesis that lymphatics would exhibit myogenic constrictions and dilations to intraluminal pressure changes. Collecting lymphatic vessels were isolated from rat mesentery, cannulated, and pressurized for in vitro study. The lymphatic diameter responses to controlled intraluminal pressure steps of different magnitudes were tested in the absence and presence of the inflammatory m...

The fish gill is the most physiologically diversified vertebrate organ, and its vasculature the most intricate. Application of vascular corrosion techniques that couple high-fidelity resins, such as methyl methacrylate, with scanning electron microscopy yields three-dimensional replicas of the microcirculation that have fostered a better appreciate gill perfusion pathways. This is the focus of ...

We report six phases of high-density nano-ice predicted to form within carbon nanotubes (CNTs) at high pressure. High-density nano-ice self-assembled within smaller-diameter CNT (17,0) exhibits a double-walled helical structure where the outer wall consists of four double-stranded helixes, which resemble a DNA double helix, and the inner wall is a quadruple-stranded helix. Four other double-wal...