Morphology of solution-grown poly(β-propiolactone) single crystals

Single crystals of poly(-propiolactone) (PPL) with different molecular weights (M _w = 70000 and M _w = 2300) were grown from four kinds of solvents under isothermal crystallization condition. The morphologies and crystal structures of PPL single crystals were investigated by means of transmission electron microscopy and atomic force microscopy. The single crystals of high-molecular-weight PPL (HMW-PPL) grown from cyclohexanone appeared elongated with dimensions of around 0.2–0.8 m along the short and 5–10 m along the long axes. Single crystals of low-molecular-weight PPL grown from cyclohexanone showed three to five elliptical-shaped lamellae, from central nucleus like petals. The long axes of both single crystals corresponded to the crystallographic b axis. The reciprocal lattice parameters: a* = 2.045 nm^–1, b* = 1.420 nm^–1 and * = 90° could be determined from electron diffractograms. Decoration of the crystals with polyethylene suqqested that the single crystals of HMW-PPL have regular chain-folding along their long axis in the [010] direction with consecutive folds in the [110] and [1 0] directions. Accordingly, it is deduced that HMW-PPL has the anti-parallel chain-packing structure.     

Guaranteed cost regulator design: A probabilistic solution and a randomized algorithm

This paper presents a gradient-based randomized algorithm to design a guaranteed cost regulator for a plant with general parametric uncertainties. The algorithm either provides with high confidence a probabilistic solution that satisfies the design specification with high probability for a randomly sampled uncertainty or claims that the feasible set of the design parameters is too small to contain a ball with a given radius. In both cases, the number of iterations executed in the algorithm is of polynomial order of the problem size and is independent of the dimension of the uncertainty.     

Osteoconduction of porous Ti metal enhanced by acid and heat treatments

Bone ingrowth into porous Ti metal is important for stable fixation of Ti metal implants to surrounding bone. However, without surface treatment this is limited to only a thin region of the outer surface of the Ti metal. In the present study, a porous Ti metal with a porosity of ~60 % and interpore connections of 70–200 micrometers in diameter was investigated in terms of its chemical and heat treatments, by implanting it into rabbit femur for periods varying from 3 to 12 weeks. The porous Ti metal subjected to heat treatment at 600 °C after H₂SO₄/HCl mixed acid treatment showed the largest bone ingrowth in comparison with those subjected to no treatment, only acid treatment, and only heat treatment even at an early stage after implantation, and remained as such even 12 weeks after implantation. Their bone ingrowths were well interpreted in terms of apatite-forming abilities of the Ti metals in body environment. Their apatite-forming abilities did not depend upon their surface roughness nor type of crystalline phase, but upon the positive surface charge.     

Red-and-green-based pseudo-RGB color models for the comparison of digital images acquired under different brightness levels

Digital images of crops and other plants are useful in plant management although the brightness of digital images varies with time. Brightness adjustment of the entire area of color digital images has been quite difficult due to the absence of correlations among color components and brightness. Redness and greenness best correlate with brightness. Hence, red- and green-based pseudo-color models could enable the adjustment of brightness of the entire area of color digital images. A pseudo-color model, a red–green–white mat model, lost most of the information on yellowness when tested with a color gamut. However, a red–green-inverted [red?+?green] model largely retained the original information. In this color model, the intensity of blue becomes the indicator of darkness. As a complementary color model, a red–green–[red?+?green] color model was examined. The color model provided pseudo-color images carrying information on redness, greenness, and yellowness. By comparing grayscale images of a single color component such as key black for the pseudo-color models, the pseudo-color models were shown to provide measures that are dimensionally independent of one another. Thus, together with the original red–green–blue (RGB) color image, the pseudo-color images almost triple the amount of information carried by the grayscale images. These multidimensional pieces of information are expected to facilitate the observation of colors of plants through digital image acquisition.     

Fabrication, characterization, and application of boron-doped diamond microelectrodes for in vivo dopamine detection

Highly boron-doped diamond (BDD) was deposited on chemically etched micrometer-sized tungsten wires using microwave plasma assisted chemical vapor deposition (MPCVD), and these were used to fabricate BDD microelectrodes. BDD microelectrodes with very small diameter (about 5 microm) and 250 microm in length could be made successfully. In addition to the unique properties of BDD electrodes, such as a very low background current, high stability, and selective oxidation of dopamine (DA) in the presence of ascorbic acid (AA), other superior properties of the microelectrodes, including a constant current response, an increase in the mass transport, and the ability for use in high resistance media were also shown. An application study was conducted for in vivo detection of DA in mouse brain, where the BDD microelectrode was inserted into the corpus striatum of the mouse brain. A clear signal current response following medial forebrain bundle (MFB) stimulation could be obtained with high sensitivity. Excellent stability was achieved, indicating that the BDD microelectrodes are very promising for future in vivo electroanalysis.     

Hydrazine degradation by ultrasonic irradiation

The influence of pH on the degradation of hydrazine with a concentration of 0.1mmol/L was investigated under the stirring (300rpm) and ultrasonic irradiation conditions (200kHz, 200W) in the pH range of 1-9. It was found that the hydrazine degradation depended greatly upon pH under the ultrasonic irradiation condition, while it did not take place over the whole pH range under the stirring condition. Although it has been known that OH radicals and hydrogen peroxide are sonochemically formed from water, it was considered that the OH radicals played an important role of the hydrazine degradation, but not hydrogen peroxide. The pH dependence of the hydrazine degradation was discussed in terms of the relationship between the chemical structure and the basic dissociation constants of hydrazine.     

Comparison of quartz and silicon as a master mold substrate for patterned media UV-NIL replica process

Nanoimprint lithography (NIL) is a promising candidate technology to fabricate patterned media for the next generation hard disk drives (HDD). The requirement of pattern pitch for the HDD or discrete-track recording (DTR) media will be as small as from 40 to 50 nm by 2011 or 2012. However not only to create such fine pitch but also long e-beam writing time such as 1 week with conventional high resolution resist ZEP520A are critical. This paper addresses the fabrication processes to combine silicon substrate and a new chemically amplified resist (CAR) for the master molds of this NIL. The e-beam writing speed with this new CAR was achieved over 3-times faster while 50 nm fine DTR patterns were demonstrated with rotary stage e-beam writer. Furthermore, the replication with J-FIL from the master mold into quartz working mold was also demonstrated.     

Mechanisms of Mycotoxin-Induced Neurotoxicity through Oxidative Stress-Associated Pathways

Among many mycotoxins, T-2 toxin, macrocyclic trichothecenes, fumonisin B(1) (FB(1)) and ochratochin A (OTA) are known to have the potential to induce neurotoxicity in rodent models. T-2 toxin induces neuronal cell apoptosis in the fetal and adult brain. Macrocyclic trichothecenes bring about neuronal cell apoptosis and inflammation in the olfactory epithelium and olfactory bulb. FB(1) induces neuronal degeneration in the cerebral cortex, concurrent with disruption of de novo ceramide synthesis. OTA causes acute depletion of striatal dopamine and its metabolites, accompanying evidence of neuronal cell apoptosis in the substantia nigra, striatum and hippocampus. This paper reviews the mechanisms of neurotoxicity induced by these mycotoxins especially from the viewpoint of oxidative stress-associated pathways.