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  • 1
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Journal of food science 41 (1976), S. 0 
    ISSN: 1750-3841
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Process Engineering, Biotechnology, Nutrition Technology
    Notes: SEM was used to determine the effect of postmortem aging (unheated) and cooking (heated to internal temperatures of 60, 70 and 80°C by broiling) on the ultrastructural characteristics of bovine longissimus and psoas major muscles. Micrographs from postmortem aged (unheated) muscle clearly showed the fibrillar and connective tissue structures of muscle. Progressive changes with increased temperature were observed in endomisial sheath swelling, collagen fiber disintegration and myo-fibril fragmentation, coagulation and shrinkage. Specifically, after heating to 70°C, banding patterns and myofibril fragmentation at Z-disks were clearly evident. Degradation of collagen fibers in the perimysium was initiated at 70°C and intense disintegration was observed at 80°C. Changes observed in psoas major were different from those in the longissimus in that intact myofibrils and tubules were observed in both the heated and unheated samples. This may be due to the “loose” packing of myofibrils unique to psoas major muscle. Furthermore, less shrinkage and coagulation of myofilaments in the A band region and wider I band regions were noted. These observations of looser packing of myoflbrils, thinner myotibril threads and wider I band regions offer additional evidence as to why steaks from psoas major muscle are more tender than those from longissimus muscle.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1749-6632
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Natural Sciences in General
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Geophysical prospecting 41 (1993), S. 0 
    ISSN: 1365-2478
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geosciences , Physics
    Notes: This study investigates the propagation of borehole Stoneley waves across permeable structures. By modelling the structure as a zone intersecting the borehole, a simple 1D theory is formulated to treat the interaction of the Stoneley wave with the structure. This is possible because the Stoneley wave is a guided wave, with no geometric spreading as it propagates along the borehole. The interaction occurs because the zone and the surrounding formation possess different Stoneley wavenumbers. Given appropriate representations of the wavenum-ber, the theory can be applied to treat a variety of structures, including a fluid-filled fracture. Of special interest are the cases of permeable porous zones and fracture zones. The results show that, while Stoneley wave reflections are generated, strong Stoneley wave attenuation is produced across a very permeable zone. This result is particularly important in explaining the observed strong Stoneley wave attenuation at major fractures where it has been difficult to explain the attenuation in terms of the single planar fracture theory. In addition, by using a simple and sufficiently accurate theory to model the effects of the permeable zone, a fast and efficient method is developed to characterize the fluid transport properties of a permeable fracture zone.
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  • 4
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Geophysical prospecting 41 (1993), S. 0 
    ISSN: 1365-2478
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geosciences , Physics
    Notes: Previous studies of radiation from point sources in fluid-filled boreholes have most often been based on far-field, stationary phase analysis. In these papers, the explicit contribution of the borehole itself acting as a waveguide has not been properly considered, with a few exceptions. In general, these studies accurately describe S-wave radiation in high-velocity rocks such as granites and limestones and P-wave radiation in most rocks, and experiments have confirmed this. However, tube waves directly influence the external wavefield and in fact create a shear-wave ‘wake’ outside the borehole due to constructive interference of tube-wave emission if a velocity condition is met. This constructive interference or wake is generated when the tube-wave velocity is greater than the shear-wave velocity. When this happens, a tube-wave complex pole invalidates the mathematical assumptions for stationary phase analysis and the stationary phase predictions do not agree with experimentally derived radiation patterns. Shales at shallow depths and other soft sediments characteristically have tube-wave velocities greater than shear-wave velocities. Because the tube-wave is of relatively high amplitude compared to body waves generated directly by the source, these secondary shear waves can be the highest amplitude arrivals on receiver arrays.The shape and properties of these secondary shear waves are calculated and shown to have identical properties to Mach waves of aerodynamics and seismology. For instance, these waves are geometrically conical and the aperture of the cone and the moveout velocity can be calculated. This paper also demonstrates the important effect that casing has on the Mach waves and provides predictions about when these waves are likely to be observed. Finally, evidence of Mach waves in data sets is examined and it is shown how these waves have been confused with receiver borehole tube waves.It is possible, though rare, that the tube-wave velocity of the borehole is greater than the compressional-wave velocity of the surrounding medium. In this case secondary compressional or compressional Mach waves would be generated although this problem is not addressed here.
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  • 5
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Geophysical prospecting 41 (1993), S. 0 
    ISSN: 1365-2478
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geosciences , Physics
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Geophysical prospecting 41 (1993), S. 0 
    ISSN: 1365-2478
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geosciences , Physics
    Notes: An exact formulation for borehole coupling, which is valid for all frequencies and all azimuthally symmetric and non-symmetric components, is presented. The borehole effects on downhole seismic measurements are studied in detail as functions of frequency, angle of incidence and polarization of an incident wave as well as geophone orientation. We found that correction for the borehole effect on downhole measurements should be made for frequencies above 500 Hz in a hard formation. In a soft formation, if the angle of incidence is well away from the resonance angle for SV incidence, no borehole correction is needed for frequencies below 300 Hz, while for frequencies above 300 Hz, the borehole can cause severe problems in downhole measurements. The borehole can also significantly alter the particle motion direction which implies that horizontal component rotation from data itself is unreliable for experiments with frequencies above 1 kHz in the hard formation and around 500 Hz in the soft formation.
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  • 7
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract: Using C8 reversed-phase HPLC in conjunction with sodium dodecyl sulfate-polyacrylamide gel electrophoresis, we have fractionated proteins contained in human CSFs obtained from patients with schizophrenic disorders. When these proteins were electrophoretically blotted onto polyvinylidene difluoride membrane for direct N-terminal amino acid sequencing, several CSF proteins were identified; these included albumin, transferrin, apolipoprotein A-l, β2-microglobulin, and prealbumin. We have also identified two structurally related human CSF proteins designated cerebrin 28 (Mr 28,000) and cerebrin 30 (Mr 30,000) that have an N-terminal amino acid sequence of NH2-APPAQVSVQPNF and NH2-APEAQVSVQPLFXQ, respectively. Comparison of these sequences with existing database at Protein Identification Resource (R 32.0), GenBank (R 72.0), SWISS-PROT (R 22.0), and EMBL (R 31.0) indicated that they are unique proteins. These proteins were subsequently purified by high performance electrophoresis Chromatography (HPEC) using an Applied Biosystems 230A HPEC system. A specific polyclonal antibody was prepared and an ELISA was established for cerebrin 30. It was noted that HPEC is a powerful tool to purify microgram quantities of proteins from human, rabbit, and rat CSFs. Using such a system, we have been able to micropurify as many as 10 proteins simultaneously in a single experiment because the elution of proteins occurred strictly according to their molecular weights. More importantly, we routinely obtained a recovery of 〉90%. The potential use of this technology for micropurification of proteins was discussed.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Journal of food science 44 (1979), S. 0 
    ISSN: 1750-3841
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Effects of rate of heating and final internal temperatures on the texture of fish gels were studied using mechanically deboned fish tissues of 2 species and 2 harvest locations. Generally, rapid heating to 85°C internal temperature (using 100°C steam) produced a firmer, more springy texture in fish gels in comparison with those heated slowly to 70°C internal temperature. However, these thermal effects on gel textures were species and harvest location dependent. Degradations of tropomyosin and myosin observed in cooked fish gels were highly related to gel textural properties. Results further suggested that changes in muscle proteins during heating were caused by proteolytic factor(s) in the sarcoplasmic fraction. The proteolytic crude fraction was isolated and partially characterized. Optimal temperature for proteolytic activity was 60°C; optimal pH was between pH 8.0 and pH 8.5; calcium ion activated the proteolytic activity and the optimal calcium ion concentration for activation was 1 mM; metal chelators, EDTA and EGTA, inhibited the proteolytic activity. A thorough understanding of these proteolytic factors and their subsequent control is important for the utilization of mechanically deboned fish tissues.
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  • 9
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Journal of food science 44 (1979), S. 0 
    ISSN: 1750-3841
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Protein functionalities were studied in comminuted fish gels from mechanically deboned fish tissues of four species after storage at −29° C up to 12 months. Differences in gel textures, which were evaluated instrumentally and by a texture profile sensory panel, were evident among fish species and time in frozen storage. Fish gel texture was not significantly related to, protein solubility of raw tissues, but was closely related to water-holding capacity and protein solubility of cooked gels. Degradation of tropomyosin and myosin probably occurred in some of the fish gels during thermal processing.
    Type of Medium: Electronic Resource
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  • 10
    ISSN: 1749-6632
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Natural Sciences in General
    Type of Medium: Electronic Resource
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