SOLUBILITY OF THE PROTEINS OF MACKEREL LIGHT MUSCLE AT LOW IONIC STRENGTH

Over 90% of the proteins of mackerel light muscle were soluble in solutions of physiological ionic strength or less. To accomplish this solublization, it was necessary to extract certain proteins at moderate ionic strength and neutral pH before extracting the rest of the myofibrillar and cytoskeletal proteins in water. Six proteins were favorably solubilized by sodium chloride solutions of moderate ionic strength at neutral pH under conditions that allowed later dissolution of myofibrillar and cytoskeletal proteins in water. The possibility is suggested that three of these proteins were involved in preventing the solubilization in water of other myofibrillar and cytoskeletal proteins of mackerel light muscle. Based on molecular masses and relative abundance, these proteins could possibly be M-protein (166 kDa), α-actinin (95 kDa) and desmin (56 kDa).     

Relation Between Multiregion Crack Growth and Dynamic Fatigue of Glass Using Indentation Flaws

The influence of transport-limited kinetic crack growth on the fatigue properties of soda-lime glass was examined. Dynamic fatigue data were taken on specimens with controlled indentation flaws and were compared with the predicted response from measured crack velocity characteristics. Heptane was used as the operational test environment because of its pronounced crack velocity plateau; control tests in water served to establish a baseline reference for comparing the results. Frac-tographic observations using a stress wave marker technique showed a complex growth history for flaws broken in heptane compared to that for flaws broken in water. The magnitude of the predicted region II influence is too small to be detected in the dynamic fatigue results, even allowing for the relatively high degree of data reproducibility. The implications of this conclusion for lifetime predictions are discussed.     

SOME FACTORS INVOLVED IN TRIMETHYLAMINE N-OXIDE (TMAO) DEMETHYLATION IN POST MORTEM RED HAKE MUSCLE

The pH optimum for demethylation of TMAO in minced red hake muscle at –5C was approximately 7.0. This value was higher than the pH optimum for the crude soluble enzyme in an anaerobic system utilizing flavin and NADH and for an aerobic system with ferric iron and ascorbate but was similar to the pH optimum observed with the flavin-NADH system in the presence of air. Both the anaerobic and aerobic flavin-NADH systems had sufficient activity in the presence of optimal concentrations of cofactors to account for all of the demethylation of TMAO observed in minced muscle. Comparison of concentrations of flavins and NADH and their rate of change during storage at temperatures both below and above freezing with previously determined kinetic constants suggest that this cofactor system may be critical in determining the rate of TMAO demethylation in post mortem red hake muscle. The extent of TMAO breakdown at –5C caused by the iron-ascorbate system was barely sufficient to account for the amount of DMA produced in the minced muscle. With the relatively low concentrations of iron and ascorbate present in the tissue, this system seems unlikely to be a major factor in TMAO degradation in situ.     

Interreaction Between Al2O3 and a CaO-Al2O3 Melt

Poly crystalline and single-crystalline α-alumina were reacted with a eutectic CaO-Al₂O₃ melt at 1530°C. A reaction zone develops in which a strongly textured CA₆ layer, as well as a CA₂ layer, forms, with a remaining layer of unreacted CaO-AI₂O₃ melt. Silica, an impurity in the α-alumina, is rejected by the advancing CA₆ phase and accumulates as calcium alumino-silicates in channels that assist in the reaction as fast transport paths. Reaction mechanisms and welding are briefly discussed.     

Multimodel Robust Control by Fast Output Sampling-An LMI Approach

An LMI approach to robust multimodel controller design is proposed. The fast output sampling control law considered here allows in theory to realize the effect of a robust state feedback gain simultaneously for a family of linear models. In practice, there are two reasons why exact realization of state feedback may not be desirable or even impossible: poor error dynamics, and noise sensitivity due to large output feedback gains. An LMI formulation of the design problem allows to approximate a robust state feedback design by fast output sampling, in a way that closeness to the original design can be traded against reducing these deteriorating effects. The proposed method is illustrated by a multivariable design example and experimental results.     

SYNTAX AND LEXICAL STATISTICS IN ANAPHORA RESOLUTION

We describe a syntactically based salience algorithm for pronominal anaphora resolution and a procedure for reevaluating the decisions of the algorithm on the basis of statistically modeled lexical semantic/pragmatic preferences. We report the results of an extensive blind test of both systems on computer manual text. We discuss the implications of these results for the comparative roles of syntactically defined salience and statistically measured lexical preference in determining the references of pronouns in text.     

Phase Equilibria in the System NaF-ThF4-UF4

Phase equilibria in the condensed system NaF-ThF₄-UF₄ were determined by cooling-curve and thermal-gradient quenching experiments from the liquidus to ∼450°C. A phase diagram of the ternary system was constructed, showing three singular points and eleven invariant points, including two eutectics, occurring in association with the primary phases of ten solid solutions and two pure solids. The eutectic mixture having the composition 75.5NaF-10.5ThF₄-14UF₄ (mole %) melts at 575°C, the lowest liquidus temperature in the system. Except for NaF, NaF-ThF₄, and ThF₄-UF₄ solid solutions, phases crystallizing from molten NaF-ThF₄-UF₄ mixtures are solid solutions formed by interchange of U⁴⁺ and Th⁴⁺ ions in NaF-ThF₄ and NaF-UF₄ compounds. No ternary compounds were found. Phase diagrams of the systems NaF-ThF₄ and NaF-UF₄, revised in the course of this study to include the newly identified phases, 7NaF.2ThF₄ and 7NaF.2UF₄, are presented. X-ray diffraction and optical data are given for the pure crystal phases, 4NaF.ThF₄, 7NaF.2ThF₄, 7NaF.2UF₄, 3NaF.UF₄, and for 3NaF.2ThF₄-5NaF.3UF₄ solid solutions. The system is unique among the fluoride systems reported in containing so wide a variety of substitutional solid solutions and in containing a continuous solid solution formed of binary compound pairs 3NaF.2ThF₄ and 5NaF.3UF₄ which are isomorphous but of different stoichiometry.