Alpha-anomer-selective glucosylation of menthol with high yield through a crystal accumulation reaction using lyophilized cells of Xanthomonas campestris WU-9701

L-Menthyl alpha-D-glucopyranoside (alpha-MenG) is a desirable derivative of L-menthol with useful properties for the production of new flavors and novel food additives. Bacteria were screened for alpha-anomer-selective glucosylation activity toward l-menthol, resulting in the isolation of two strains, Xanthomonas campestris WU-9701 and Stenotrophomonas maltophilia WU-9702, from independent soil samples. Since the safety of X. campestris for use in the food industry is well established, WU-9701 was selected as the more suitable strain for further study. When 50 mg X. campestris WU-9701 lyophilized cells as a biocatalyst were incubated with 1.0 M maltose and 100 mg L-menthol in 10 ml of 10 mM H3BO3NaOHKCl buffer (pH 8.0) at 40 degrees C, alpha-MenG was accumulated, mainly in a crystalline form, through the anomer-selective synthesis reaction without any by-product formation. Under the optimal conditions, 202 mg alpha-MenG was obtained over 48 h with a highest conversion yield of 99.1% based on the supplied L-menthol. Crude alpha-MenG formed through this "crystal accumulation reaction" was easily collected from the reaction mixture by separation on filter paper. Plank-like crystals of purified alpha-MenG were subsequently obtained by recrystallization in ethyl acetate solution.     

F.E.T. theory of strip-coupled Rayleigh-wave amplifier

It is shown that information can be transferred from one strip to another across a finite gap in which the carrier wave is subject to rapid decay. Each region in which a metal strip is located above the semiconductor, and insulated from it, is treated as an individual f.e.t. amplifier, exciting in the semiconductor a conduction current which flows into the adjacent similar region. Hence the carrier-wave decay between strips is unimportant. The effect of substituting ohmic contacts for the insulated `gates? is discussed as an extension of this theory.     

Input correlation with the a.s.w. storage correlator

By correlating during read-in, we correlate signals of much greater length than could be stored within the device, thereby obtaining a large improvement in t.b. product.     

Preparation and characterization of multilayered hydroxyapatite/silk fibroin film

We prepared multilayered films consisting of silk fibroin (SF) and hydroxyapatite (HAp) by alternating lamination using untreated SF and HAp-deposited SF films. Untreated SF films were prepared from a regenerated SF solution by air drying. HAp-deposited SF films were prepared by soaking methanol-treated SF films containing >5 wt% CaCl2 in a simulated body fluid with the ion concentration 1.5-fold higher than that of the standard one. The multilayered HAp/SF films had HAp layers with approximate thicknesses of 3-5 microm and SF layers with thicknesses of 40-70 microm. The bonding strength between the SF and HAp layers was significantly affected by temperature and compression time under the lamination method. The optimal conditions for achieving the maximum T-peel strength and beta-sheet contents were determined to be 130 degrees C for 4 min. The Young's modulus of the multilayered films (133.4 MPa) was higher than that of the films consisting of SF alone (92.5 MPa) under swollen conditions. The biocompatibility of the HAp-deposited SF films was analyzed by culturing of osteoblasts (MC3T3-E1) on a film. The results indicate that HAp-deposited SF films and SF films show similar degrees of cell adhesion and alkaline phosphatase activities.     

Simultaneous multilayer arthrotomography of the temporomandibular joint using photostimulable phosphor computed radiography

OBJECTIVE: To compare the image quality of photostimulable phosphor computed radiography (CR) with that of a conventional screen-film system for simultaneous multilayer arthrotomography of the temporomandibular joint (TMJ). METHODS: X-ray attenuation, resolution and granularity was compared. Simultaneous multilayer tomography of TMJ was performed using a skull phantom and diagnostic quality of bone structures estimated. The clinical outcome is demonstrated in two typical cases. RESULTS: X-ray attenuation was larger with CR. Granularity was more prominent in edge-enhanced CR images and was associated with inferior diagnostic quality. However, it was improved by using a higher tube voltage. Clinical CR without edge enhancement showed a similar resolution to the conventional system but this decreased with enhancement. In an enhanced arthrotomogram, the boundary between contrast medium, bone and soft tissue were clearly defined and a fibrous adhesion also easily seen. CONCLUSION: Photostimulable phosphor CR is an acceptable alternative for simultaneous multilayer arthrotomography of the TMJ.     

Effects of carbamylcholine chloride on human antral gastrin mRNA levels

The effects of the muscarinic receptor agonist, carbamylcholine chloride (carbachol), on gastrin release and gastrin mRNA levels in human antral mucosa (n = 15) were determined. During a-2-h incubation period, carbachol (10(-6)-10(-4) M) decreased gastrin mRNA levels to 71 +/- 8% (10(-6) M), 40 +/- 8% (10(-5) M), and 33 +/- 5% (10(-4) M) of control levels. Carbachol (10(-5) M) decreased intracellular gastrin (from 1634 +/- 103 to 1272 +/- 126 pg/mg tissue protein), while it increased gastrin release into the medium (from 609 +/- 48 to 918 +/- 68 pg/ml per mg tissue protein). After 6- and 9-h culture, carbachol gradually increased gastrin mRNA levels, by 96 +/- 12% and 126 +/- 23%, respectively. Atropine sulfate (10(-5) M) completely inhibited the carbachol-induced changes. Cycloheximide markedly decreased tissue gastrin concentration, but increased gastrin mRNA levels, whereas it had no effects on gastrin release. These findings suggested that carbachol may have a time-related biphasic action on human antral gastrin biosynthesis.     

Deposition of bone‐like apatite on modified silk fibroin films from simulated body fluid

Silk fibroin films with various calcium chloride contents were prepared by a cast film method and subsequent MeOH treatment. The conformational changes from α‐helix to β‐sheet structure were analyzed by Fourier transformed infrared attenuated total reflection spectroscopy measurements. The films obtained were soaked in 1.5‐times simulated body fluid (1.5 SBF) and the deposition of hydroxyapatite crystals were observed by scanning electron microscopy. The films with calcium chloride contents lower than 3 wt % relative to the silk fibroin were not mineralized under these conditions, while those with calcium chloride contents more than 5 wt % mineralized after 6 h. The X‐ray diffraction patterns and inductive coupled plasma spectroscopy analyses indicated that the hydroxyapatite crystals were grown by hydrolysis of octacalcium phosphate, as indicated by differences in diffraction intensities and changes in concentrations of calcium and phosphate ions in 1.5 SBF. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci, 2006     

Monolithic waveguide zinc-oxide-on-silicon convolver

A monolithic waveguide zinc-oxide-on-silicon convolver has been constructed and operated at a centre frequency of 125 MHz. The zinc oxide is originally deposited over the whole substrate and then etched to form the waveguide. The waveguide width is 1/10 of the beam width at the input transducers, which should yield a 20 dB improvement in efficiency over a normal convolver with a beam width equal to the transducer width, after accounting for the loss in the input tapers. Such an improvement was observed in experimental devices.     

Surface-wave parametric signal processing

The parametric interaction of surface-wave signals propagating in opposite directions on a lithium-niobate substrate has been used to obtain the crosscorrelation of digitally coded input signals. The output 4 cm interdigital transducer was separated from the substrate by a 2000 ? SiO2 layer to eliminate scattering into volume waves. Matched-filter responses for both amplitude-modulated and biphase Barker codes of up to 13 bits have been obtained.