Heart, chemical composition

K. Christiansen and P.K. Jensen, Membrane-bound lipid particles from beef heart chemical composition and structure, Biochim. Biophys. Acta, 1972, 260, 449-459. 

One hint of possible trouble to come is provided by the information we described in Chapter 4, related to airborne particulate matter (PM). The available evidence ascribes significant increases in the risks of asthma and other respiratory diseases, certain cardiovascular conditions, and lung cancer to PM exposure, particularly those that average less than 2.5 pm (2500 nm) in size. As we noted, the chemical composition of these particles varies widely, depending upon source, but may not be as important as particle size as a risk determinant. Moreover, there is some experimental evidence pointing to the so-called ultra-fines, PM with dimensions below 100 nm, as significant contributors to PM risk. In addition some experimental studies have demonstrated that ultrafines not only distribute themselves throughout the airways, but seem to be able to translocate to other parts of the body - liver, heart, perhaps the CNS. 

In this study, we have attempted to obtain a detailed, quantitative estimate of the surface chemical composition of two commercially available polyurethanes, i.e., Biomer and Avcothane, which have demonstrated a reasonable degree of blood compatibility. For example, Avcothane has been used as an intraaortic balloon pump for post-operative patients (5). Biomer also has been successfully used for artificial heart components in calves (14). 

Amino acid sequence analysis and determination of subunit composition are painstaking but these steps are usually necessary before further structural investigations are undertaken. It should not be forgotten that chemical composition and amino acid sequencing provided a foundation for recent structure-function findings in the cytochrome oxidase field. The complete amino acid sequence and a successful prediction of the number of a-helices greatly contributed to the successful and rapid crystallographic analysis of bovine heart cytochrome c oxidase at 2.8 resolution, four years ago (Tsukihara et al., 1995 Tsukihara et al., 1996). 

The ion-selective membrane is the heart of an ISE as it controls the selectivity of the electrode. Ion-selective membranes are typically composed of glass, crystaUine, or polymeric materials. The chemical composition of the membrane is designed to achieve an optimal permselectivity toward the ion of interest. In practice, other ions exhibit finite interaction with membrane sites and will display some degree of interference for, determination of an analytei ion. In chnical practice, if the interference exceeds an acceptable level, a correction is required. 

Approximately 95% of total lipids of LD from bovine heart are constituted by TAG. The amount of protein present in these LD is about 5% of total mass, and the amount of phospholipids varies from 3 to 7% of total lipid. The major phospholipids forming the monolayer of these LD are phosphatidylcholine (ca. 50%) and phosphatidylethanolamine (30-40%). The NEFA content is very low. The chemical composition of LD in beef heart with their high TAG content and the rather small amount of phospholipids resembles the composition of chylomicrons. A striking difference, however, is the lack of cholesterol and cholesteryles-ters in LD from beef heart whereas these lipid species occur at approximately 1-2% of total lipid in chylomicrons. Furthermore, the protein content of LD is two to three times higher than of chylomicrons. In contrast to bovine heart LD, those of stellate cells from the rat liver consist of retinylesters, TAG, free cholesterol and a small amount of phospholipids [142]. A general characteristic of LD regardless of the cell type appears to be the content of approximately 5% phospholipids of the total mass (reviewed in Ref. [143]). 

This edition tries to emphasize that the soil and soil solution are the center and heart of the environment. The chemical composition of the biosphere, hydrosphere, and atmosphere depend,s greatly on the chemistry of the soil. 

A helium microwave cavity plasma or MIP serves as the heart of a unique instmment dedicated to the analysis of particles with diameters between 1 and 20 pim. The analysis of small particles is becoming increasingly important in fields as diverse as the semiconductor industry where extremely low levels of contaminants can destroy semiconductor chips, to indoor and outdoor air quality and the health impact of respirable particles. This instrument is basically an atomic emission spectrometer, but designed to count particles, calculate particle size, and determine the chemical composition of each particle analyzed, one by one. 

This book examines popular tree nuts (almond, Brazil nut, cashew, hazelnut, macadamia, pecau, pine nut, pistachio, and walnut) together with chesmut aud heart nut, and describes each tree nut s compositional and lipid characteristics, phytochemicals, and health effects. Chemical composition of acorn nut, beech nut, coconut, and hickory are also briefly covered. In addition, the book provides a comprehensive assessment of allergens and antiaflatoxigenic activity of phytochemicals and sphin-golipids, and health benefits of tree nuts as weU as their flavor and volatile compounds. Where avaUable, information on the bioactives and phytochemicals of tree nut by-products is included. Peanut, which is actually a legume, is not discussed in this book as a separate chapter, but where necessary it is used for comparison with tree nuts. 

The surface of any material governs its interactions with the environment. Knowledge over and control of these interaction is especially important when a material is in contact with the biosystem, for example, when applied as transplant, in tissue engineering, in cell cultures, and in blood contact, as weU as in biosensors in medicinal diagnosis, fluids analysis, environmental moititoring, and many other areas. Whereas, on the one hand, the bulk properties of the material are essential for its successful application, for example, as a catheter or a heart valve, special attention has to be paid to render to the surface suitable biocompatible or bioactive properties, no matter of the chemical composition of the bulk material. This is usually achieved by any surface modification process by low molar mass or polymeric compounds. An essential feature of such a modification procedure is the need for a permanent and bioresistant surface finish [87]. 

Dean B B, Kolattukudy P E, Davis R W 1977 Chemical composition and ultrastructure of suberin from hollow heart tissue of potato tubers Solarium tuberosum). Plant Physiol 59 1008-1010... 

Micro-Electromechanical Systems The measure of the intelligence of this and other systems is both the range and time of response to changes in the monitored equipment or environment. This is most often ensured by micro-electromechanical systems (MEMS), miniature components which measure and process such parameters as acceleration, pressure, distance, temperature, light and the chemical composition of an atmosphere. The heart of MEMS is a processing unit (microprocessor) made in the form of an integrated circuit on a silicon board. The board is then chemically etched and layers of other materials are deposited to make a sensor. Typical features of a MEMS fabricated in this way are shown in Fig. 7.5. Thanks to their small size, sensors in MEMS are characterised by low inertia, which makes it possible to quickly start and stop their functions. Moreover, thanks to their integration with the microprocessor in one substrate, their response to external stimuli is sent to the microprocessor almost immediately. 

Fig. 2.1. Schematic diagram of a reaction model. The heart of the model is the equilibrium system, which contains an aqueous fluid and, optionally, one or more minerals. The system s constituents remain in chemical equilibrium throughout the calculation. Transfer of mass into or out of the system and variation in temperature drive the system to a series of new equilibria over the course of the reaction path. The system s composition may be buffered by equilibrium with an external gas reservoir, such as the atmosphere.

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