An Enzymatic Assay Method for Bacterial Alpha-amylase Using a Glucose Determination-kit and Maltohexaose as the Substrate

Using maltohexaose G₆ as a substrate, a convenient analytical method for amylase-catalyzed hydrolytic reaction was developed by application of an enzymatic assay-kit (glucose oxidase-peroxidase) to measurement of glucose, produced on the reaction: G₆→G₅ + G. The initial velocity was confirmed to be proportional to the initial concentration of amylase, examined, ∼ 100 μm. The new method was found in a good correlation with the Nelson and Somogyi method. Rate assay was also examined: The initial velocity is proportional to the enzyme concentration, ∼ 30 μm. Hence, this enzymatic assay method is recognized to be convenient and useful for the measurement of α-amylase.     

Design and control of compliant tensegrity robots through simulation and hardware validation

To better understand the role of tensegrity structures in biological systems and their application to robotics, the Dynamic Tensegrity Robotics Lab at NASA Ames Research Center, Moffett Field, CA, USA, has developed and validated two software environments for the analysis, simulation and design of tensegrity robots. These tools, along with new control methodologies and the modular hardware components developed to validate them, are presented as a system for the design of actuated tensegrity structures. As evidenced from their appearance in many biological systems, tensegrity (‘tensile–integrity’) structures have unique physical properties that make them ideal for interaction with uncertain environments. Yet, these characteristics make design and control of bioinspired tensegrity robots extremely challenging. This work presents the progress our tools have made in tackling the design and control challenges of spherical tensegrity structures. We focus on this shape since it lends itself to rolling locomotion. The results of our analyses include multiple novel control approaches for mobility and terrain interaction of spherical tensegrity structures that have been tested in simulation. A hardware prototype of a spherical six-bar tensegrity, the Reservoir Compliant Tensegrity Robot, is used to empirically validate the accuracy of simulation.     

Study on the beam transport from the Bio-Nano ECRIS

The beam transport of N(+) ion and C(60)(+) ion in the Bio-Nano ECRIS with min-B configuration was investigated based on the ion beam profiles. The N(+) beam could be focused under the low-beam current conditions. Also the C(60)(+) beam could be focused in spite of the large space-charge effect which will lead the divergence of the beam. We confirmed that our beam transport system works well even for the C(60)(+) ion beam. We estimated the highest C(60)(+) beam current with the focused beam profile by comparing the N(+) ion beam.     

Preparation and properties ofgem-dichlorocyclopropane derivatives of long-chain fatty esters

Methyl oleate (18∶1) and linoleate (18∶2) were readily transformed to the correspondinggem-dichlorocyclopropane derivatives in high yield, using triethylbenzylammonium chloride as the phase-transfer catalyst in the presence of aqueous NaOH and CHCl₃. Reaction of dichlorocarbene with methyl 12-hydroxystearate furnished methyl 12-chlorostearate (49%) and 12-O-formylstearate (19%). The hydroxy group in methyl ricinoleate was protected (O-tetrahydropyran-2′-yl) prior to dichlorocyclopropanation of the ethylenic bond. Removal of the protecting group allowed the hydroxy group to be converted to a chloride,O-acetyl, azido orO-formyl function. Treatment of methyl ricinoleate with thionyl chloride, followed by the reaction with dichlorocarbene gave the corresponding 12-chloro-dichlorocyclopropane derivative. The dichlorocyclopropane derivative of oleic acid was transformed to a C₁₉ allenic fatty acid when treated witht-butyl lithium. However, the remaining dichlorocyclopropane derivatives, containing an additional functional group in the alkyl chain, failed to yield the corresponding allenic derivatives. All derivatives were characterized by a combination of spectroscopic and chromatographic techniques, including infrared,¹H nuclear magnetic resonance (NMR), and¹³C NMR spectroscopy.     

Synthesis of novel tri- and tetrasubstituted C<Subscript>18</Subscript> furan fatty esters

A methylene-interrupted C₁₈ keto-acetylenic fatty ester (methyl 12-oxo-9-octadecynoate) was obtained from methyl ricinoleate by bromination-dehydrobromination followed by oxidation. Reaction of methyl 12-oxo-9-octadecynoate with bis(benzonitrile) palladium(II) chloride, allyl bromide, or methyl-allyl bromide furnished methyl 8-[5-hexyl-3-allyl-furan-2-yl]-octanoate (1, 56%) or methyl 8-[5-hexyl-3-(2-methyl-allyl)-furan-2-yl]-octanoate (2, 55%). Reaction of methyl 12-oxo-11-chloro-or 11-fluoro-9-octadeyynoate (prepared from methyl santalbate-methyl 11-E-9-octadecynoate, found in sandalwood, Santalum album, seed oil) with bis(benzonitrile) palladium(II) chloride gave methyl 8-(4-fluoro-5-hexyl-furan-2-yl)-octanoate (3, 50%) or methyl 8-(4-fluoro-5-hexyl-furan-2-yl)-octanoate (4, 50%), respectively. And when methyl 12-oxo-11-chloro- or 11-fluoro-9-octadecynoate was treated with a mixture of bis(benzonitrile) palladium(II) chloride, allyl bromide, or methyl-allyl bromide, the reaction yielded tetrasubstituted C₁₈ furan derivatives, viz, methyl 8-(3-allyl-4-chloro-5-hexyl-furan-2-yl)-octanoate (5, 54%), methyl 8-[4-chloro-5-hexyl-3-(2-methyl-allyl)-furan-2-yl)-octanoate (6, 54%), methyl 8-(3-allyl-4-fluoro-5-hexyl-furan-2-yl]-octanoate (7, 10%), and methyl 8-[4-fluoro-5-hexyl-3-(2-methyl-allyl)-furan-2-yl]-octanoate (8, 10%). The presence of a fluorine atom in the furan derivatives 4, 7, and 8 was readily characterized by the appearance of doublets for carbon nuclei, which were coupled to the fluorine atom in the ¹³C NMR spectra. All furan fatty derivatives from this work were characterized by NMR spectroscopic and mass spectrometric analyses. The yields of compounds 7 and 8 were very low (10%) despite attempts to improve the procedure by increasing the amounts of the reactants and catalyst.     

Tensile fatigue of a laminated carbon-carbon composite at room temperature

The tensile fatigue behavior of a cross-ply carbon-carbon (C/C) laminate was examined at room temperature. Tension-tension cyclic fatigue tests were conducted under load control at a sinusoidal frequency of 10 Hz to obtain stress-fracture cycles (S-N) relationship. The fatigue limit of the C/C was found to be 213 MPa (93% of the tensile strength), and no fracture was observed at over 10⁴ cycles. The residual tensile strength of specimens that survived fatigue loading was enhanced with increase in fatigue cycles and applied stress. Observations of the fatigue-loaded specimens revealed that the formation of micro-cracks at the fiber-matrix interfaces was facilitated during fatigue loading. These interfacial cracks were concluded to protect the fibers from being damaged by matrix cracks and this behavior was considered to be the governing mechanism of strength enhancement by fatigue loading.     

Nitroanilines enhancing the holographic data storage characteristics of the 9,10‐phenanthrenequinone‐doped poly(methyl methacrylate) photopolymer

This article describes an approach toward improving the characteristics of a photopolymer for holographic data storage application. The maximum diffraction efficiency (η_max) and dynamic range (M#) of 9,10‐phenanthrenequinone (PQ)‐doped poly(methyl methacrylate; PMMA) both improved significantly after co‐doping with one of three nitroanilines—N,N‐dimethyl‐4‐nitroaniline (DMNA), N‐methyl‐4‐nitroaniline (MNA), and 4‐nitroaniline (pNA). In particular, the value of η_max increased from 38% for the PMMA/PQ system to 72% for the PMMA/PQ/DMNA system (a 1.89‐fold improvement) and the value of M# increased accordingly from 2.7 to 7.3 (a 2.70‐fold improvement). Thus, the holographic data storage characteristics of PMMA/PQ photopolymers can be improved through co‐doping with nitroaniline compounds. We also investigated the mechanism of the nitroaniline‐induced improvement in optical storage performance using proton nuclear magnetic resonance and X‐ray photoelectron spectroscopy. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

A Novel Method of Measuring Moisture Content Distribution in Timber During Drying Using CT Scanning and Image Processing Techniques

A new method for the nondestructive measurement of moisture content (MC) distribution in timber during drying was developed using X-ray computed tomography (CT) scanning and image processing techniques. The deformed cross section in the CT images due to shrinkage was corrected with the image registration, and the shrinkage was measured by digital image correlation analysis. The pixel-wise MC distributions during drying were measured and visualized successfully. The total timber MC estimated from the MC values of each pixel were strongly correlated with those measured by calculation without geometrical transformation of CT images. The coefficient of determination (R ²) and the standard error of prediction (SEP) were 0.99 and 0.18%, respectively, within the MC range of 19.2–47.3%. In addition, the measured shrinkage distribution during drying was in accordance with the diamonding deformation observed. The results suggest that CT scanning combined with image processing techniques is an effective tool for nondestructive assessment of MC distribution during drying.     

Synergistic Extraction of Am(III) and Eu(III) by Tris(2‐pyridylmethyl)Amine with Various Anions in 1,2‐Dichloroethane

The extraction equilibria of Am(III) and Eu(III) by using a tripodal ligand, tris(2‐pyridylmethyl)amine (tpa), with various lipophilic anions have been investigated. The extractability of both Am(III) and Eu(III) was increased by the combination of tpa and counteranions due to a synergistic effect. The separation factors between Am(III) and Eu(III) were also increased from 7.6 to 49 by the combination of counteranions and organic solvents. The extraction equilibria of Am(III) and Eu(III) with tpa in 1,2‐dichloroethane were determined by slope analysis. It was found that three anions and one molecule of the ligand coordinated to Am(III) and Eu(III) was extracted regardless of the anions.