Development of a ligation-based impedimetric DNA sensor for single-nucleotide polymorphism associated with metabolic syndrome

Single-nucleotide polymorphism (SNP) detection is becoming important in molecular diagnostics, clinical assay, and novel drug development. Electrochemical methods are well suited for the DNA diagnostics system. Since electrochemical reactions directly emit an electronic signal, expensive signal transduction equipment is not required. We describe the development of a novel DNA sensor that utilizes impedance spectroscopy and DNA ligation reaction on a gold electrode. Impedance spectroscopy enables label-free detection and is nondestructive and useful in equivalent circuit models for interpretation on an electrode surface, whereas from the ligation reaction, the specificity is derived by the allele-specific oligonucleotide of the capture probe on immobilized gold electrode. In other words, DNA diagnostics system using the combination of impedance spectroscopy and ligation reaction is simple, rapid, and allele specific. In this report, we have described a ligation-based impedimetric DNA sensor and the analysis of Trp64Arg polymorphism in the beta3-adrenergic receptor gene (ADRβ3).     

Permeabilities of alkyl p-aminobenzoates through living skin equivalent and cadaver skin

The in vitro permeabilities of alkyl p-aminobenzoates through living skin equivalent (LSE) and cadaver skin were compared. Methyl, ethyl, and butyl p-aminobenzoates were used as model compounds. The permeabilities of these compounds through LSE and cadaver skin from an aqueous drug suspension were determined with a flow-through diffusion cell. The permeability coefficients of these esters in LSE were an order of magnitude higher than in cadaver skin. This was primarily because of low resistances offered by the outermost layer (i.e., stratum corneum) of LSE. In the case of cadaver skin, the permeability coefficient increased as the carbon chain length increased, whereas no appreciable change in the permeability coefficients of these esters in LSE was observed. These results clearly suggest that the LSE membrane offered very little resistance as opposed to cadaver skin. Therefore, the LSE membrane may not quantitatively represent a good human skin model for evaluating skin permeation of a drug from topical or transdermal formulations.     

Inter-laboratory validation studies of analytical method for determination of chloramphenicol in royal jelly

Inter-laboratory validation studies were conducted in 6 laboratories to validate the analytical method for determination of chloramphenicol in royal jelly. Chloramphenicol spiked at the levels of 0.1 and 0.5 ppm was analyzed. Mean recoveries were 89 and 89%, reproducibility relative standard deviations (RSD(R)) were 10.5 and 6.8%, HORRAT(R) values were 0.5 and 0.4. Samples containing residues at the levels of 0.25 and 0.80 ppm were analyzed. Mean recoveries were 89 and 84%, RSD(R) were 9.8 and 12.3%, and HORRAT(R) values were 0.5 and 0.7. The determination limit was 0.05 ppm. These results show that this method has good performance.     

汽车发动机用无Co排气阀座圈材料的开发

烧结合金广泛地用于制作汽车发动机阀座圈（VSI）。就增高耐热与耐磨耗性能而言，在合金化设计上，烧结合金远比常规的锻钢与铸造合金灵活。特别足，一些高钻烧结材料由于耐磨耗与耐热性高而广泛用作排气阀座圈材料。鉴于近来将发动机的A／F比（空气／燃料比）调整到比常规的贫化（即空气／燃料比增高），排气阀座圈的工作环境趋于严酷。这种A／F比贫化的趋向旨在减少排出的废气和减低燃料消耗。另一方面。也需要不断地减少使用像钴之类环境负荷高的材料。同时，钴昂贵，减低钴含母有利于节省这些材料。这篇论文详细报道了无钴、无铅及有利于环境的排气阀座矧的开发与使用。     

Adaptation mechanism of interlimb coordination in human split-belt treadmill walking through learning of foot contact timing: a robotics study

Human walking behaviour adaptation strategies have previously been examined using split-belt treadmills, which have two parallel independently controlled belts. In such human split-belt treadmill walking, two types of adaptations have been identified: early and late. Early-type adaptations appear as rapid changes in interlimb and intralimb coordination activities when the belt speeds of the treadmill change between tied (same speed for both belts) and split-belt (different speeds for each belt) configurations. By contrast, late-type adaptations occur after the early-type adaptations as a gradual change and only involve interlimb coordination. Furthermore, interlimb coordination shows after-effects that are related to these adaptations. It has been suggested that these adaptations are governed primarily by the spinal cord and cerebellum, but the underlying mechanism remains unclear. Because various physiological findings suggest that foot contact timing is crucial to adaptive locomotion, this paper reports on the development of a two-layered control model for walking composed of spinal and cerebellar models, and on its use as the focus of our control model. The spinal model generates rhythmic motor commands using an oscillator network based on a central pattern generator and modulates the commands formulated in immediate response to foot contact, while the cerebellar model modifies motor commands through learning based on error information related to differences between the predicted and actual foot contact timings of each leg. We investigated adaptive behaviour and its mechanism by split-belt treadmill walking experiments using both computer simulations and an experimental bipedal robot. Our results showed that the robot exhibited rapid changes in interlimb and intralimb coordination that were similar to the early-type adaptations observed in humans. In addition, despite the lack of direct interlimb coordination control, gradual changes and after-effects in the interlimb coordination appeared in a manner that was similar to the late-type adaptations and after-effects observed in humans. The adaptation results of the robot were then evaluated in comparison with human split-belt treadmill walking, and the adaptation mechanism was clarified from a dynamic viewpoint.     

Modification of dispersibility of nanodiamond by grafting of polyoxyethylene and by the introduction of ionic groups onto the surface via radical trapping

To improve the dispersibility of polycrystalline nanodiamond (ND) in solvents, the grafting of polymers and introduction of ionic groups onto ND surface via radical trapping by ND surface were investigated. The grafting of polyoxyethylene (POE) onto ND surface by trapping of POE radicals formed by the thermal decomposition of POE macro azo-initiator (Azo-POE) was examined. The polymer radicals formed by the thermal decomposition of Azo-POE were successfully trapped by ND surface to give POE-grafted ND. The effect of temperature on the grafting of POE onto ND was discussed. In addition, the introduction of cationic protonated amidine groups onto ND was achieved by the trapping of radicals bearing protonated amidine groups formed by thermal decomposition of 2,2′-azobis(2-methylpropionamidine)dihydrochloride (AMPA). The anionic carboxylate groups was introduced onto ND surface by the trapping of the radicals bearing carboxyl groups formed by thermal decomposition of 4,4′-azobis(4-cyonovaleric acid) (ACVA) followed by the treatment with NaOH aqueous solution. The dispersibility of ND in water was remarkably improved by the grafting of POE, based on the steric hindrance of polymer chains and by the introduction of ionic groups, based on the ionic repulsion, onto ND surface.     

Wide distribution of [3H](-)-epigallocatechin gallate, a cancer preventive tea polyphenol, in mouse tissue

The increasing recognition of green tea and tea polyphenols as cancer preventives has created a need for a study of their bioavailability. For this purpose, we synthesized [3H] (-)-epigallocatechin gallate ([3H]EGCG) with a specific activity of 48.1 GBq/mmol and directly administered the solution into the stomachs of CD-1 female or male mice. Radioactivity in the digestive tract, various organs, blood, urine and feces was measured with an oxidizer at various times after administration and significant radioactivity was found in the previously reported target organs of EGCG and green tea extract (digestive tract, liver, lung, pancreas, mammary gland and skin), as well as other organs (brain, kidney, uterus and ovary and testes) in both sexes. Incorporation of radioactivity in the cells was confirmed by microautoradiography. Within 24 h, 6.6 (females) and 6.4% (males) of total administered radioactivity was excreted in the urine and 37.7 and 33.1% in feces. HPLC analysis of urine from both sexes revealed that 0.03-0.59% of administered [3H]EGCG, along with at least five metabolites, was excreted. In addition, we found that a second, equal administration to female mice after a 6 h interval enhanced tissue levels of radioactivity in blood, brain, liver, pancreas, bladder and bone 4-6 times above those after a single administration. These results suggest that frequent consumption of green tea enables the body to maintain a high level of tea polyphenols and this paper is the first pharmacological evidence of a wide distribution of [3H]EGCG in mouse organs, indicating a similar wide range of target organs for cancer prevention in humans.     

Echogenic fetal bowel in the third trimester associated with trisomy 18

Obstructive sleep apnea has been associated with various cardiac arrhythmias; however, supraventricular tachycardia has not been reported to occur in this disorder. This case report describes a patient who developed episodes of supraventricular tachycardia during periods of apnea and oxygen desaturation. With the initiation of nasal continuous positive airway pressure during sleep, the arrhythmia was abolished. The etiology and possible mechanisms responsible for the supraventricular tachycardia are discussed.     

Newly identified Chinese hamster ovary cell mutants are defective in biogenesis of peroxisomal membrane vesicles (Peroxisomal ghosts), representing a novel complementation group in mammals

We isolated peroxisome biogenesis-defective mutants from Chinese hamster ovary cells by the 9-(1'-pyrene)nonanol/ultraviolet (P9OH/UV) method. Seven cell mutants, ZP116, ZP119, ZP160, ZP161, ZP162, ZP164, and ZP165, of 11 P9OH/UV-resistant cell clones showed cytosolic localization of catalase, a peroxisomal matrix enzyme, apparently indicating a defect of peroxisome biogenesis. By transfection of PEX cDNAs and cell fusion analysis, mutants ZP119 and ZP165 were found to belong to a novel complementation group (CG), distinct from earlier mutants. CG analysis by cell fusion with fibroblasts from patients with peroxisome biogenesis disorders such as Zellweger syndrome indicated that ZP119 and ZP165 were in the same CG as the most recently identified human CG-J. The peroxisomal matrix proteins examined, including PTS1 proteins as well as a PTS2 protein, 3-ketoacyl-CoA thiolase, were also found in the cytosol in ZP119 and ZP165. Furthermore, these mutants showed typical peroxisome assembly-defective phenotype such as severe loss of resistance to 12-(1'-pyrene)dodecanoic acid/UV treatment. Most strikingly, peroxisomal reminiscent vesicular structures, so-called peroxisomal ghosts noted in all CGs of earlier Chinese hamster ovary cell mutants as well as in eight CGs of patients' fibroblasts, were not discernible in ZP119 and ZP165, despite normal synthesis of peroxisomal membrane proteins. Accordingly, ZP119 and ZP165 are the first cell mutants defective in import of both soluble and membrane proteins, representing the 14th peroxisome-deficient CG in mammals, including humans.