نتایج جستجو برای: permeability reduction
تعداد نتایج: 538898 فیلتر نتایج به سال:
In this work the likelihood of asphaltene deposition problems during dynamic displacement of oil by natural gas in unconsolidated porous media is experimentally inspected. The two different rock materials, limestone and sandstone, are used as a representative of porous media. Dynamic flow experiments indicate that the increase of natural gas injection inc...
a significant problem in multicarrier communication systems is the necessity to reduce the value of papr (peak-to-average power ratio) of transmitting signal. in this thesis we study the effect of the system parameters such as coding and modulation types on papr and ultimate ber in a mc-cdma system. in this study we consider fading channel as well as the nonlinearity of transmitter’s amplifier ...
Although Beadle a9 early as 1937 suggested that the urine of Nereis diversicolor O. F. Miiller might be of lower concentration than the body fluids when this worm is hyperregulating in low salinities, there has been no direct measurement of urine concentration to support this reasonable idea. Jorgensen & Dales (1957) studied osmotic water uptake and loss in N. diversicolor and calculated that t...
BACKGROUND/AIMS Although high-flux (HF) dialyzers with enhanced membrane permeability are widely used in current hemodialysis (HD) practice, urea kinetic modeling is still being applied to indicate the adequacy of both low-flux (LF) and HF HD. In comparison with urea (molecular weight, 60 Da) and beta(2)-microglobulin (beta(2)MG, 12 kDa), cystatin C (CyC, 13 kDa) is a larger molecule that has a...
Endothelial properties are affected by mechanical stresses. Several studies have shown that an acute application of shear stress increases the permeability of endothelial monolayers in culture. We investigated whether more prolonged application of shear has the opposite effect. Porcine aortic endothelial cells were cultured on Transwell filters to assess monolayer permeability to albumin. The m...
OBJECTIVE The molecular mechanisms regulating vascular permeability are only now being elucidated. The junctional adhesion molecule (JAM) JAM-C has been linked to the induction of vascular permeability. We sought to understand the mechanism whereby JAM-C may disrupt junctional integrity in endothelial cells (ECs). METHODS AND RESULTS We show here that JAM-C alters permeability through modulat...
Hayden, Ursula L., and Hannah V. Carey. Neural control of intestinal ion transport and paracellular permeability is altered by nutritional status. Am J Physiol Regulatory Integrative Comp Physiol 278: R1589–R1594, 2000.—This study examined the effect of fasting on the neural control of ion transport and paracellular permeability in piglet jejunum. Muscle-stripped tissues from fed or 48-h fasted...
Increased intestinal permeability has been implicated in various pathologies, has various causes, and can develop during vigorous athletic training. Colostrum bovinum is a natural supplement with a wide range of supposed positive health effects, including reduction of intestine permeability. We assessed influence of colostrum supplementation on intestinal permeability related parameters in a gr...
Context Eroded dentin might present the opening of dentinal tubules, increasing permeability, and consequently dentinal hypersensitivity. Aims This study evaluated the permeability of dentin surfaces exposed to different levels of erosion and methods of surface protection. Materials and Methods Dentine samples (3 mm × 3 mm × 1 mm) were prepared from bovine incisors (n = 90) and divided into...
There is increasing evidence that diabetic retinopathy is a primary neuropathological disorder that precedes the microvascular pathology associated with later stages of the disease. Recently, we found evidence for altered functional properties of synaptic α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors in A17, but not AII, amacrine cells in the mammalian retina, and the ob...
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