Alpha-II-spectrin after controlled cortical impact in the immature rat brain

Proteolytic processing plays an important role in regulating a wide range of important cellular functions, including processing of cytoskeletal proteins. Loss of cytoskeletal proteins such as spectrin is an important characteristic in a variety of acute central nervous system injuries including ischemia, spinal cord injury and traumatic brain injury (TBI). The literature contains extensive information on the proteolytic degradation of alpha-II-spectrin after TBI in the adult brain. By contrast, there is limited knowledge on the characteristics and relevance of these important processes in the immature brain. The present experiments examine TBI-induced proteolytic processing of alpha-II-spectrin after TBI in the immature rat brain. Distinct proteolytic products resulting from the degradation of the cytoskeletal protein alpha-II-spectrin by calpain and caspase 3 were readily detectable in cortical brain parenchyma and cerebrospinal fluid after TBI in immature rats.

Intermolecular multiple quantum coherences at high magnetic field: The nonlinear regime

Experiments have been carried at magnetic-field strengths of 9.4, 14.1, and 17.6 T to explore the evolution of intermolecular multiple quantum coherences in the nonlinear regime where the system evolves for times that are much greater than the characteristic time of action of the long-range dipolar field, tau(d). The results show the expected Bessel function form of the recorded signal as a function of time of evolution, with evident zeros and sign changes. As expected, the rate of signal evolution increases at higher-field strengths as a result of the increased equilibrium magnetization. A numerical method for calculating the evolution of magnetization under the action of the distant dipolar field, relaxation, and diffusion that is based on Fourier analysis of the magnetization distribution has been applied to the correlated two-dimensional spectroscopy revamped by asymmetric z-gradient echo detection sequence in the nonlinear regime and shown to produce results that are in good agreement with experimental data acquired at different magnetic fields and rates of spatial modulation. Experiments and simulations have also been used to explore the evolution of magnetization in a mixture of two interacting spin species in the nonlinear regime.

The use of magnetic resonance imaging to track controlled drug release and transport in the brain

A method has been developed to track controlled drug release and transport in the brain. This method entails the use of a polymeric implant to release, over time, a paramagnetically labelled compound into the brain. Magnetic resonance imaging is used to determine the evolving concentration distribution. This method is well suited to other types of intracranial drug delivery systems as well as to track transport in other organs of the body.

Magnetic resonance imaging: applications of novel methods in studies of porous media

NMR imaging is finding broad applications in nonbiological areas including the study of fluid flow and fluid ingress in porous media. The porous media include at the one end mineral rocks and various building materials through various solid plastic materials to foodstuffs at the other end of the spectrum. The fluids within these various media range from crude oil and water mixtures, and water itself, to a range of organic solvents in plastic materials. This paper is concerned with the flow and ingress of water through Bentheimer sandstone and Ninian reservoir specimens, and also in solid nylon blocks.

Discrimination of Crude Oil and Water in Sand and in Bore Cores With NMR Imaging

Summary

Nuclear magnetic resonance (NMR) imaging techniques were used to study the mobile proton content in prepared samples containing mixtures of crude oil, water, and sand. The measured proportions of viscous crude oil agree well with the actual values. proportions of viscous crude oil agree well with the actual values. Discrimination of light crude oil and water was demonstrated by proton, chemical shift differences. A bore core sample also was proton, chemical shift differences. A bore core sample also was examined and gave clear images from its oil content.

Introduction

Research on the displacement of crude oil by other fluids-e.g., water, natural gas, nitrogen, carbon dioxide, or aqueous solutions-seeks to determine the efficiency of oil recovery and the stability of such a process under various conditions. To study the relative importance of the factors that influence oil displacement research, nonintrusive X-ray and neutron radiographic techniques have been developed to measure the flood saturations and flow patterns in high-pressure coreflooding experiments. With these patterns in high-pressure coreflooding experiments. With these measurements, it is possible to distinguish two or more phases within samples contained in steel or alloy pressure vessels. phases within samples contained in steel or alloy pressure vessels. X-ray computed tomography (CT) was another method developed for medical and industrials applications and can be used to obtain information on the distribution and flow of fluids within core samples. NMR measures fluid saturations and relative permeabilities in drill core material, but the new technique of NMR imaging now offers a promising means to determine the distribution, flow, and mobility behavior of proton-containing liquids in solids. To date, the major application of NMR imaging is in medicine, where it detects differing water concentrations among the various tissues and organs of the human body. The information obtained in a noninvasive manner yields detailed two- or three-dimensional images of the interior structure of animals and humans. In addition to the medical and biological uses of NMR imaging, a number of solid- and liquid-state applications in the study of materials could be used in the petroleum industry. Because NMR imaging measures more than proton density, it is inherently more informative than radiographic techniques. It is also much less hazardous. Special features of many NMR imaging techniques include the ability to measure the flow of liquids and to distinguish between two different static liquids using the differences in intrinsic NMR properties, such as the spin-lattice and the spin-spin relaxation times, t and t, and chemical shifts. With these properties, NMR imaging has the potential to provide detailed information properties, NMR imaging has the potential to provide detailed information about the chemical nature of different fluids. This type of information would be difficult (if not impossible) to obtain by other methods. The extent to which the potential for core analysis is realized undoubtedly will depend on instrumental developments in the NMR imaging technique. In this paper we present a preliminary evaluation of the applicability of NMR imaging to measure oil and water in core material. We examined fabricated samples containing known concentrations of crude-oil/water mixtures dispersed in sand where both the effect of different crude oil types and diffusion of water were monitored. An actual core sample also was examined.

Experimental Procedure

Samples. Three 1.97-in. [50-mm] -diameter glass tubes were packed in different sections (Sections A through E) with different concentrations of crude oil, water, and sand (see Fig. 1). Sample 1 was packed with a highly viscous aromatic crude oil (Tia Juana Persado), and the different compartments were isolated from each Persado), and the different compartments were isolated from each other by rubber membranes. Sample 2 was constructed similarly but without rubber membranes so that diffusion of fluids could occur. In addition, this sample contained a globule of oil in Section E. The imaging measurements were made about 2 months after the sample had been constructed. Sample 3 used a much less aromatic and more mobile crude oil (North Sea Brent field) and incorporated rubber membranes. It was imaged about 7 days after construction.

NMR Imaging Measurements. All NMR measurements were made with proton resonances at 30 x 106 cycles/sec [30 MHz]. proton resonances at 30 x 106 cycles/sec [30 MHz]. SPEFE

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