PURIFICATION OF REACTIVE SULFHYDRYL ENZYMES BY BIOSELECTIVE ADSORPTION ON MONOMERIC AVIDIN: PURIFICATION OF SULFHYDRYL OXIDASE1

ABSTRACT A biotinylation-bioselective adsorption procedure was developed for single-step purification of bovine sulfhydryl oxidase from solubilized skim milk membrane vesicles. Sulfhydryl oxidase was specifically biotinylated by reaction of its chemically reactive sulfhydryl group with a disulfide-containing biotinylation reagent giving a mixed disulfide between the enzyme and the biotinyl moiety. The biotinylated enzyme was then selectively adsorbed on a monomeric avidin matrix. After washing all nonspecifically bound proteins from the matrix, the enzyme was released by reduction of the disulfide with dithiothreitol. Both the biotinylation and the isolation are performed at pH 7.0 under extremely mild conditions. The resulting enzyme preparation appeared to be homogeneous by gel electrophoresis and the specific activity increased over 3000 fold in comparison to whey. The monomeric avidin matrix can be regenerated and used indefinitely. This purification procedure should be generally applicable to proteins with a chemically reactive sulfhydryl group.     

Entanglement of orbital angular momentum for the signal and idler beams in parametric down-conversion

We calculate the anticipated correlation between measurements of the orbital angular momentum of the signal and idler beams for parametric down-conversion. These calculations apply to the experiments where the orbital angular momentum state is measured by the use of computer-generated holograms. Displacement of these holograms with respect to the beam axis allows the measurement of superpositions of Laguerre—Gaussian modes. The correlations between such superposition modes of the signal and idler beams show their entanglement and could be used for Bell-type tests of nonlocality.     

Comparison of numerical methods for solving Liapunov matrix equations†

A numerical comparison is made of most published methods for solving the linear matrix equations which arise when a quadratic form Liapunov function is applied to a constant linear system (continuous or discrete, real or complex). Generally, for the real equations direct methods are satisfactory for systems of order ten or less, whereas for larger order systems iterative methods (based upon expressing the solution in terms of an infinite series) are to be preferred. For the complex equations the most convenient numerical method uses an explicit representation for the solution in terms of the eigenvalues and vectors of the system matrix. If the system matrix is in companion form then algorithms taking account of this structure offer minor improvements.     

AN ALTERNATIVE PERSPECTIVE ON FUZZY SET-BASED APPROXIMATE REASONING

Abstract

On the subject of fuzzy set-based approximate reasoning, this paper attempts to present a perspective that is both rigorously stated and different from the standard approach as stated by Mamdani and many others. Functionally speaking, this alternative perspective produces results essentially the same as the standard one, and in fact we intend to prove that subject to certain assumptions the results will be exactly die same. We feel however that the alternative perspective offers advantages in that it makes a more appropriate and more understandable use of such concepts as fuzzy relations, the extension principle, and fuzzy composition. If indeed it can lead to a clearer and more widespread understanding of the approximate reasoning formalism then this could conceivably spark broader interest in fuzzy control and other applications.     

Estimation of storage space requirements using multiple regression

Two equations hove been obtained using regression analysis techniques which can be applied to determine storage space requirements with acceptable accuracy and minimum effort. By defining all items by means of a common parameter—packing factor—it was possible to ignore the individual weights of each item, yet still load the transport and storage unit to some practical load limits. The method used in this paper is general and can be applied to similar problems with different boundary conditions.     

Retrodiction as a tool for micromaser field measurements

We use retrodictive quantum theory to describe cavity field measurements by successive atomic detections in the micromaser. We calculate the state of the micromaser cavity field prior to detection of sequences of atoms in either the excited or ground state, for atoms that are initially prepared in the excited state. This provides the POM elements, which describe such sequences of measurements.     

A low magnetic field gyrotron—gyro-magnetron

A gyrotron device operating at a substantially reduced magnetic field is proposed. The operating beam voltage is moderately low and the waveguide circuit resembles the anode block of a conventional magnetron. The dispersion relationship is given. A proof of principle experiment is suggested.     

Correlation of Ethanol Concentration with Sensory Classification of Decomposition in Canned Salmon

Canned salmon samples of four species (sockeye, pink, coho, and chum) were analyzed for ethanol content. A highly significant correlation (r = 0.71, p < 0.001, Pearson;r = 0.80, p = 0.001, Spearman) was found between the ethanol content and the sensory classification of decomposition in canned salmon. This relationship has potential use as a means of objectively confirming the initial sensory classification of canned salmon.     

The Sterols and Triterpenes of Banana Pulp

SUMMARY: Using thin-layer chromatography and gas-liquid chromatography the following substances were identified in banana pulp (Musa saplentum L.): Cycloartenol, cycloeucalenol, 24-methylene cycloartanol, campesterol, β-sitosterol and stigmasterol. The major triterpene was 24-methylene cycloartanol while β-sitosterol accounted for greater than 72% of the sterol fraction.