Molecular motion of syndiotactic poly(α-methylstyrene) in solution studied by carbon-13 n.m.r. relaxation measurements

The carbon-13 n.m.r. spin-lattice relaxation times, nuclear Overhauser enhancement factor (NOE), and line widths have been measured for a syndiotactic poly(α-methylstyrene) in solutions in toluene-d₈ and o-dichlorobenzene-d₄ as a function of temperature from 40° to 163δC. The single correlation time model of relaxation is inadequate to explain the data of spin-lattice relaxation time and NOE. But, within experimental error, these relaxation data in two solvents over a full temperature range can be interpreted in terms of either the Cole-Cole or the log-χ² distributions of correlation times, or a conformational jump model proposed by Monnerie et al. The internal rotation of the methyl group is relatively rapid, while that of the phenyl ring is slow and practically overshadowed by the backbone segmental reorientation over the temperature range examined. The solvent dependence of relaxation data was discussed.     

Synovial osteochondromatosis of the temporo-mandibular joint

A rare case of synovial osteochondromatosis of the temporo-mandibular joint is presented. Important diagnostic information can be obtained by CT, MRI, 99m Tc bone scan and aspiration biopsy. Observation using a light microscope showed mild cellular atypia, but the hallmarks characteristic of chondrosarcoma were not found. Observation using an electron microscope showed the mature chondrocytes contained a well-developed rough endoplasmic reticulum. Histological evaluation indicated that the present case was benign synovial osteochondromatosis in an early stage.     

Enzymatic Hydrolysis of Recovered Protein from Frozen Small Croaker and Functional Properties of Its Hydrolysates

ABSTRACT:  Fish protein isolate were recovered from frozen small croaker using pH shift. The partial enzymatic hydrolysates were fractionated as soluble and insoluble parts. They were dried using the drum dryer and their functional properties were examined. The total nitrogen content of the enzymatic hydrolysates ranged from 12.9% to 13.7%. The degree of hydrolysis of precipitates was 18.2% and 12.2% for croaker hydrolysates treated with Protamex 1.5 MG ( Bacilllus  protease complex) and Flavourzyme 500 MG (endoproteases and exoproteases, Aspergillus oryzae ), respectively. The TCA supernatant, after centrifugation of hydrolysates, contained numerous peptides ranging from 100 to 4000 daltons. The solubility of the supernatants was higher than that of the precipitates at 0% to 3% NaCl and pH 2 to 10. The precipitate of Flavourzyme- and Protamex-treated hydrolysates showed a high emulsion activity index value compared to egg white and bovine plasma protein. In addition, the highest emulsion stability was observed for Protamex-treated precipitate hydrolysates. Emulsion stability of Protamex-treated precipitate hydrolysates was comparable to those of protein additives (egg white, bovine plasma protein, and soy protein concentrate). Water and fat binding capacity of precipitates were higher than those of supernatant. The results indicate that precipitate hydrolysate from undersized croaker can be used in processed muscle foods as a functional and nutritional ingredient.     

Construction of Cellulose Binding Domain Fusion FMN-Dependent NADH-Azoreductase and Glucose 1-Dehydrogenase for the Development of Flow Injection Analysis with Fusion Enzymes Immobilized on Cellulose

The cellulose binding domain (CBD) of cellulosome-integrating protein A from Clostridium thermocellum NBRC 103400 was genetically fused to FMN-dependent NADH-azoreductase (AZR) and glucose 1-dehydrogenase (GDH) from Bacillus subtilis. The fusion enzymes, AZR-CBD and CBD-GDH, were expressed in Escherichia coli Rosetta-gami B (DE3). The enzymes were purified from cell-free extracts, and the specific activity of AZR-CBD was 15.1 U/mg and that of CBD-GDH was 22.6 U/mg. AZR-CBD and CBD-GDH bound strongly to 0.5 % swollen cellulose at approximately 95 and 98 % of the initial protein amounts, respectively. After immobilization onto the swollen cellulose, AZR-CBD and CBD-GDH retained their catalytic activity. Both enzymes bound weakly to 0.5 % microcrystalline cellulose, but the addition of a high concentration of microcrystalline cellulose (10 %) improved the binding rate of both enzymes. A reactor for flow injection analysis was filled with microcrystalline cellulose-immobilized AZR-CBD and CBD-GDH. This flow injection analysis system was successfully applied for the determination of glucose, and a linear calibration curve was observed in the range of approximately 0.16–2.5 mM glucose, with a correlation coefficient, r, of 0.998.     

High capacitance B/C/N composites for capacitor electrodes synthesized by a simple method

The B/C/N composites were synthesized by a very simple method, that is, carbonization at HTT = 800-1200 °C of the precursor prepared by drying a solution mixture of polyacrylamide and boric acid, followed by boiling in water to remove borate by-products. The amount of insoluble B species in the composite increased linearly from 4.8 to 18.6 mass% with raising HTT. The XRD and FT-IR revealed that turbostratic h-BN started to form at around 1000 °C as a by-product. By XPS, major B and N components in the composite were B-N bond, C-B-O type B, pyridinic N, pyrrolic N, and quaternary N. A fraction for B-N bond including h-BN in the total B or N components increased with raising HTT and it exceeded 50 at% between 900 and 1000 °C. It was suggested that in the composites formed at HTT > 1000 °C the amounts of h-BN increased, leading to reduction in other B and N components. The S_BET was almost unchanged up to 1000 °C, 410-420 m² g⁻¹. Large and broad redox peaks arisen from plural reactions appeared in the cyclic voltammogram (CV) measured in 1 mol dm⁻³ H₂SO₄ for the composites formed at HTT ≤ 1000 °C. These peaks disappeared in 1 mol dm⁻³ solutions of Na₂SO₄ and Li₂SO₄. By comparing CV with that for C/N composite formed from PAA by the MgO template method, the pseudo-capacitance owing to reactions of B-N and C-B-O components with protons was found to be added to commonly observed pseudo-capacitance for nitrogen-doped carbons. The capacitances for the composites formed at 850-950 °C exceeded 300 F g⁻¹ at 2 mV s⁻¹ in the acid electrolyte and the retention at 50 mV s⁻¹ was 78-80%. The shape of CV in the neutral electrolytes was trapezoid and the current density increased with lowering potential, suggesting adsorption and desorption of Na⁺ and Li⁺ ions. This was considered to be due to doped nitrogen, indicating the development of pseudo-capacitance. The capacitance per S_BET was 0.33-0.74 F m⁻² and 0.17-0.32 F m⁻², larger for lower HTT, in the acid and neutral electrolytes, respectively.     

Functional binders for reversible lithium intercalation into graphite in propylene carbonate and ionic liquid media

Poly(acrylic acid) (PAA), poly(methacrylic acid) (PMA), and poly(vinyl alcohol) (PVA), which have oxygen species as functional groups, were utilized as a binder for graphite electrodes, and the electrochemical reversibility of lithium intercalation was examined in PC medium and ionic liquid electrolyte, lithium bis(trifluoromethanesulfonyl)amide dissolved in 1-butyl-1-methylpyrrolidinium bis(trifluoromethanesulfonyl)amide (BMP-TFSA). Columbic efficiency of 75–80% with more than 300 mAh g^?1 was achieved upon first reduction/oxidation cycle in both electrolytes using these binding polymers, which were significantly improved in comparison to a conventional PVdF binder (less than 45% of columbic efficiency for the first cycle). For the graphite-PVdF electrode, co-intercalation and/or decomposition of PC molecules solvating to Li ions were observed by the electrochemical reduction, resulting in the cracking of graphite particles. In contrast, the co-intercalation and decomposition of PC molecules and BMP cations for the first reduction process were completely suppressed for the graphite electrodes prepared with the polymers containing oxygen atoms. It was proposed that the selective permeability of lithium ions was attained by the uniform coating of the graphite particles with PAA, PMA, and PVA polymers, because the electrostatic interaction between the positively charged lithium ions and negatively charged oxygen atom in the polymer should modulate the desolvation process of lithium ions during the lithium intercalation into graphite, showing the similar functions like artificial solid-electrolyte interphase.     

Solidification microstructure-dependent hydrogen generation behavior of Al–Sn and Al–Fe alloys in alkaline medium

This work deals with the development of quantitative correlations of hydrogen evolution performance with solidification microstructural and thermal parameters in Al–1Sn, Al–2Sn, Al–1Fe, and Al-1.5Fe [wt.%] alloys. The cellular growth as a function of growth and cooling rates is evaluated using power type experimental laws, which allow determining representative intervals of microstructure length scale for comparison purposes with the results of immersion tests in 5 wt%NaOH solution. For both Al alloys systems, hydrogen evolution becomes slower as the alloy solute content increased. However, for a given alloy composition, whereas a more homogeneous distribution of Sn-rich particles promotes faster hydrogen generation using Al–Sn alloys, coarsening of Al₆Fe IMCs (intermetallic compounds) fibers favors hydrogen production using Al–Fe alloys. When solidification conditions that result in a range of cellular spacings within 16 and 19 μm are considered, the specific hydrogen production of the Al-1wt.%Fe alloy is higher than that of the other studied alloys.     

Efficient High-Power Green Beam Generation by Use of an Intracavity Frequency-Doubled Laser-Diode-Pumped Q-Switched Nd:YAG Laser

An intracavity frequency-doubled diode-side-pumped Nd:YAG laser has been developed. A maximum green power of 20 W was generated at 20-kHz repetition rate with 14.2% optical-to-optical conversion efficiency and 5.3% electrical-to-optical conversion efficiency.