Molecular orbital study of pyrolytic carbons based on small cluster models

Molecular orbital calculations are applied to the Raman scattering and ESR of pyrolytic carbons on the basis of small cluster models. The E_2g and A_1g modes of C-C stretching vibrations of coronene, hexabenzocoronene, and circumcoronene, which belong to D_6h carbon clusters, are shown to appear around the 1550 cm⁻¹ and 1360 cm⁻¹ bands, respectively. The unpaired electrons observed in pyrolytic carbons are attributed to the bond-alternation defects on odd-numbered carbon clusters that are more easily mobile than those of trans-polyacetylene.     

Solid-state source of atomic oxygen for low-temperature oxidation processes: application to pulsed laser deposition of TiO2:N films

An atomic oxygen (AO) source has been redesigned to coordinate with a pulsed laser deposition system and used to grow nitrogen-doped TiO(2) films by deposition of TiN and simultaneous irradiation of the substrate with AO. The AO source uses an incandescently heated thin tube of zirconia as an oxygen permeation media to generate pure AO of low kinetic energy. The emission flux is calibrated using a silver-coated quartz crystal microbalance. The thin shape of the probe and transverse emission geometry of this emission device allow the emission area to be positioned close to the substrate surface, enhancing the irradiation flux at the substrate. AO irradiation is crucial for formation of TiO(2) phases via oxidation of the deposited TiN laser plume, and is effective for decrease of the substrate temperature for crystallization of anatase phase to as low as around 200 °C.     

Toxicity of anionic detergents determined by Saccharomyces cerevisiae microarray analysis

Sodium n-dodecyl benzene sulfonate (LAS) and sodium dodecyl sulfate (SDS) are popular anionic detergents (surfactants) that are used worldwide and the toxicities of these chemicals have been characterized. We applied these chemicals in a DNA microarray bioassay and determined that the microarray data reflects previous findings and also provides some new information about anionic detergent toxicity. The mRNA expression profiles suggest that LAS and SDS cause damage to membranes and alterations in carbon metabolism, and induce the oxidative stress response. We also found that LAS and SDS induce the pleiotropic drug-resistance network, and that LAS and SDS may be pumped out of yeast cells by this network. Hierarchical clustering of the expression profiles showed that LAS and SDS cause similar features of toxicity and that the toxicity is similar to that of capsaicin but different from that of cadmium and mercury.     

Migration of butene isomers onto the acidic OH groups in small micropores of ferrierite

Kinetics on the adsorption of n-butene onto the acidic OH groups existing in the small pores of ferrierite (FER) were studied between 233 and 253 K by IR spectroscopy. The activation energies for the adsorption of 1-butene and cis-2-butene were estimated as 23.3 and 28.4 kJ mol⁻¹, while that of trans-2-butene was not obtained due to its rapid adsorption. The activation energy for adsorption was considered to have resulted from the diffusion of n-butene molecules into the small micropores of FER.     

Nanogel bottom-up gel biomaterials for protein delivery: Photopolymerization of an acryloyl-modified polysaccharide nanogel macromonomer

Polysaccharide nanogels are one of the most attractive carriers for drug delivery systems. Nanogels encapsulate proteins in their hydrated polymer networks, and minimize the denaturation of proteins. In this study, we demonstrated the cross-linking of acryloyl group-modified polysaccharide nanogels via photopolymerization, which allowed the formation of novel hydrogel particles and macrogels. The mechanical properties of the resultant hydrogels depended on the concentrations of the nanogels and the cross-linkers. The most significant property of the nanogel-cross-linked hydrogel was the ability to encapsulate insulin via hydrophobic interactions. After incubation of the hydrogel containing insulin in water, the hydrogel was degraded by hydrolysis, and insulin was gradually released from the hydrogels over a period of 1 week. According to these results, this nanogel-cross-linked hydrogel prepared via photopolymerization has potential for innovative biomaterials.     

Multivariate analysis of C NMR spectra of methacrylate copolymers and homopolymer blends

¹³C NMR spectra of copolymers of methyl methacrylate and tert-butyl methacrylate with various chemical compositions, the homopolymers of the two methacrylates, and blends of the homopolymers with various blend ratios were subjected to principal component analysis. The first and second principal components correlated chemical composition and the randomness of comonomer sequence, respectively. Chemical composition of the copolymers was determined with high accuracy and precision by the partial least-squares regression without assignment of individual resonance peaks.     

Color simulation method for accurate prediction of resulting dyed hair color

When choosing hair dyes, it is natural for the user to assume that the final hair color will resemble the color indicated on the product container or color chart. Often, however, the result is quite different. The ability to accurately predict resulting hair color after dyeing is essential, but not easy to attain because hair varies significantly from person to person. In this paper, a new method for predicting the dyed hair state is proposed. Our method is based on a model, where the observed final color consists of contribution from three layers of the hair structure: a melanin-containing layer, a bleached layer and a pigment-colored layer. A method for predicting the final color from responses in each layer is introduced. In this method, response formulae for each layer are derived from the energy balance, and the predicted hair color after dyeing is obtained by calculating the each equation assuming that the hair state before dyeing is solely because of the contribution from the melanin-containing layer. In addition, a small measuring apparatus utilizing this prediction method was developed and the effectiveness of our method demonstrated by data obtained before and after the hair dyeing.     

Acacia(sen) SUPERGUM™ (Gum arabic): An evaluation of potential health benefits in human subjects

This study evaluated the cardiovascular and renal effects of dietary fibre supplementation with Acacia(sen) SUPERGUM™ (gum arabic) in normal individuals and a group of diabetic nephropaths. The normal diet was supplemented with 25 g of SUPERGUM™ daily for a period of 8–12 weeks.For the whole cohort dietary supplementation with SUPERGUM™ resulted in a fall in mean systolic blood pressure [SBP] (138.4 ± 18.9 mmHg to 132.83 ± 15.9 mmHg p = 0.01). Of note was a significant fall in SBP seen in normal individuals who neither had hypertension nor diabetes (129.1 ± 8.3 mmHg vs 123.6 ± 11.5 mmHg, n = 10 p = 0.02).Parameters of arterial stiffness were examined in patients with diabetic nephropathy and a fall in MAP. In this subgroup there was a significant fall in both central systolic and diastolic blood pressures, with no alterations in AI, AI @75 or PWV. This suggests that the beneficial effects of SUPERGUM™ on blood pressure are not the result of alterations in arterial stiffness.There were no effects of SUPERGUM™ on renal function and haemodynamics in patients with diabetic nephropathy. In contrast a reversible change in GFR (113.0 ml min vs 99.4 ml/min, p = 0.02) and ERPF (489.7 ml/min vs 463.0 ml/min, p = 0.04) was shown in the population of healthy volunteers.The key finding of this study is the a significant beneficial effect of dietary supplementation with SUPERGUM™ on blood pressure which is seen in both a patient group with diabetes and mild renal involvement as well as in a normal healthy normotensive cohort.     

A visualization study on relationship between water-droplet behavior and cell voltage appeared in straight, parallel and serpentine channel pattern cells

It is a critical issue to understand the relationship between water-droplet behavior and cell voltage for the establishment of PEFC water management. We fabricated three cells, whose channel pattern is different: straight one channel, parallel three channels and serpentine one channel. We operated these different channel-pattern cells and visualized water droplets in cathode channel, with systematically changing operation condition to quantitatively compare the performance and water droplet behavior between the cells. Successive process of water behavior, named as flooding, plugging and flushing, emerged in every channel-pattern cell. However, the each channel pattern cell also has inherent water behavior, showing particular cell voltage variation. Within our experimental condition, the serpentine one channel cell showed a superior tolerance to flooding and the highest performance among the three cells.