Selective isopentane formation from CH3OH on a new one-atomic layer ZrO2/ZSM-5 hybrid catalyst

A new one-atomic layer ZrO₂/ZSM-5 hybrid catalyst was prepared by using the repeated reactions between Zr(OC₂H₅)₄ and of the OH groups of the external surfaces of ZSM-5, followed by calcination. The one-atomic layer ZrO₂ attached on the ZSM-5 surface was characterized by means of X-ray diffraction, X-ray fluorescence and EXAFS. The ZrO₂ overlayer is suggested to epitaxially grow on the ZSM-5(001) plane in a [111] direction of tetragonal ZrO₂. The one-atomic layer ZrO₂/ZSM-5 is a unique catalyst which produces selectively isopentane from CH₃OH.     

Fate of herbicide CNP in rivers and agricultural drainages

The occurrence and fate of a herbicide CNP (2,4,6-trichlorophenyl-4′-nitrophenylether) in rivers and agricultural drainages was investigated. CNP residues in water samples were extracted by adsorption on a macroreticular XAD-2 resin column and subjected to gas chromatographic analysis using an electron capture detection after desorption from the column and concentration. The minimum detectable amount was 0.04 ng and a positive identification of CNP residue in water samples was obtained with a combined gas chromatography-mass spectrometry-computer system when 500 ng of CNP was injected. CNP residues were detected in water samples taken in June to September, and these levels were between 0.01 and 16.67 μg l⁻¹. The maximum level was found in a sample taken on 13th July, 1977, about a month after beginning rice seedling transplantation, and the minimum level was detected on August 29th, 1977. However CNP residue levels were increased again in September because flooded water on the paddy fields was excluded. CNP was more persistent in the aquatic environment than a herbicide benthiocarb.     

Two-dimensional multiarray formation of hepatocyte spheroids on a microfabricated PEG-brush surface

A two-dimensional microarray of ten thousand (100 x 100) hepatocyte heterospheroids, underlaid with endothelial cells, was successfully constructed with 100 microm spacing in an active area of 20 x 20 mm on microfabricated glass substrates that were coated with poly(ethylene glycol) brushes. Cocultivation of hepatocytes with endothelial cells was essential to stabilize hepatocyte viability and liver-specific functions, allowing us to obtain hepatocyte spheroids with a diameter of 100 microm, functioning as a miniaturized liver to secret albumin for at least one month. The most important feature of this study is that these substrates are defined to provide an unprecedented control of substrate properties for modulating cell behavior, employing both surface engineering and synthetic polymer chemistry. The spheroid array constructed here is highly useful as a platform of tissue and cell-based biosensors and detects a wide variety of clinically, pharmacologically, and toxicologically active compounds through a cellular physiological response.     

Copolymerization of glycidylmethacrylate–methylmethacrylate–divinylbenzene in cyclohexane

The copolymerization of glycidylmethacrylate–methylmethacrylate–divinylbenzene in cyclohexane was studied as an example of crosslinking precipitation copolymerization. The resultant copolymer is fine spheroidal. The copolymerization proceeds acceleratively at first, then steadily, and gradually slows down. The larger the divinylbenzene concentration, the smaller is the copolymerization rate. Glycidylmethacrylate is preferentially incorporated in the copolymer.     

Occurrence,horizontal transfer and degeneration of VDE intein family in Saccharomycete yeasts

VDE is a homing endonuclease gene originally discovered as an intervening element in VMA1s of Saccharomyces cerevisiae. There have been two independent subfamilies of VDE, one from S. cerevisiae strain X2180-1A and the other from Saccharomyces sp. DH1-1A in the host VMA1 gene, and they share the identity of 96.3%. In order to search the occurrence, intra/interspecies transfer and molecular degeneration of VDE, complete sequences of VMA1 in 10 strains of S. cerevisiae, eight species of saccharomycete yeasts, Candida glabrata and Kluyveromyces lactis were determined. We found that six of 10 S. cerevisiae strains contain VDEs 99.7-100% identical to that of the strain X2180-1A, one has no VDE, whereas the other three harbour VDEs 100% identical to that of the strain DH1-1A. S. carlsbergensis has two VMA1s, one being 99.8% identical to that of the strain X2180-1A with VDE 100% identical to that of the strain DH1-1A and the other containing the same VMA1 in S. pastorianus with no VDE. This and other evidence indicates that intra/interspecies transmissions of VDEs have occurred among saccharomycete yeasts. Phylogenetic analyses of VMA1 and VDE suggest that the S. cerevisiae VDEs had branched earlier than other VDEs from an ancestral VDE and had invaded into the host loci as relatively late events. The two VDEs seemed to degenerate in individual host loci, retaining their splicing capacity intact. The degeneration of the endonuclease domains was distinct and, if compared, its apparent rate was much faster than that of the protein-splicing domains.     

Determination of captafol,cyhexatin, 1-naphthylacetic acid and quintozene in apple,Japanese pear and melon by simultaneous extraction

A simple and rapid method is described for the determination of the non-registered pesticides, captafol, quintozene (PCNB), cyhexatin and 1-naphthylacetic acid (NAA), in fruits. These pesticides were extracted with acidified acetone, then captafol and PCNB were purified with a Florisil mini column and analyzed by GC-ECD. Cyhexatin was ethylated with ethylmagnesium bromide, and the ethyl derivative was analyzed by GC-FPD (Sn filter). NAA was purified with liquid-liquid extraction and determined by HPLC equipped with a fluorescence detector. These analytes were identified with GC/MS or LC/MS. The minimum identified concentration of the pesticides was below 0.2 ng per injection, which corresponds to a detection limit of below 0.02 microgram/g in the original samples. Recoveries of the pesticides spiked at 0.1 microgram/g into apple, Japanese pear and melon were greater than 61%.     

Analysis and evaluations of logical instructions called in parallel digital optical operations based on optical array logic

The authors have analysed and evaluated a two-dimensional instruction set of parallel operation based on optical array logic (OAL), which is a digital optical computing paradigm, to clarify efficient composition of an optical computing system based on OAL. To evaluate parallel operation based on OAL, the author have introduced new indices and evaluated a logical instruction set of various parallel operations with the indices, so that a guideline for composing a simple and efficient OAL computing system is clarified. Also, the authors have proposed the reduced operation kernel set correlation technique to perform parallel operations more efficiently by a simple OAL computing system. It has been clarified that the technique can reduce the required hardware necessary for an OAL computing system for efficient general-purpose processing.     

Effects of steroid hormones on vascular functions

The purpose of this review is to present reported findings of effects of steroids on vascular function and to discuss the biological significance in vascular physiology and pathology. Steroid hormones play various roles in vascular functions through the specific receptor localized in the endothelium and underlying vascular smooth muscle cells (VSMCs). Estrogen replacement therapy in postmenopausal women is in general associated with a reduction in mortality from cardiovascular disease and the beneficial effects of estrogens are caused by modulation of lipid metabolism, expression of leukocyte adhesion molecules, and migration of VSMCs in the vascular wall. Estrogens also play a role as vasodilators through an increment in nitric oxide (NO) production in endothelium or modulation of calcium homeostasis in VSMCs. Some progestin molecules partially oppose the effects of estrogens on vascular functions, but striking differences exist among the types of molecules. Testosterone shows a vasorelaxant response, but detailed actions of androgens on vascular functions remain unknown. Glucocorticoids act on vasoconstriction through reduced prostacyclin production, increased alpha-adrenoceptor numbers, and inhibition of NO synthase, while mineralocorticoids induce hypertrophy and hyperplasia of VSMCs and perivascular fibrosis and cause peripheral vascular resistance, in addition to changes in vascular electrocyte permeability. Some rapid actions of steroids are mediated by "nongenomic" responses in vascular tissues. Recent studies have also demonstrated that steroid-producing or -metabolizing enzymes are expressed in the vascular wall, suggesting the local regulation of steroids in the vascular system. Thus, steroid hormones greatly influence vascular functions and an understanding of the mechanisms may provide new means to prevent vascular diseases.     

Simulated crepitus and its reality-based specification using wearable patient dummy

Physical therapists are trained in manual examination techniques to test the impaired motor functions of patients. In this study, we have introduced a wearable robotic dummy joint to simulate disordered joint resistances or behaviors to support physical therapists in learning such techniques. We developed a discontinuous joint friction model based on a stick-slip phenomenon to simulate knee joint resistances caused by crepitus, a typical symptom accompanied by osteoarthritis. Practicing therapists participated in a reality-based evaluation test and specified acceptable parameter sets to adjust the simulated crepitus for the exoskeletal patient robot. The simulated crepitus and wearable dummy joint are expected to support the training of physical therapists.     

Fracture Energy of an Aligned Porous Silicon Nitride

The fracture energy of a porous silicon nitride with aligned fibrous grains was investigated, using a chevron-notched-beam technique. A crack was constrained to propagate normal to the grain alignment. The obtained fracture energy was ∼500 J/m², which was ∼7 times larger than that of a dense silicon nitride with randomly oriented fibrous grains. The large fracture energy was attributable primarily to the sliding resistance associated with interlocking grains.