Search Results - (Author, Cooperation:H. Matsumura)

2016-02-26

American Association for the Advancement of Science (AAAS)

0036-8075

1095-9203

Biology

Chemistry and Pharmacology

Computer Science

Medicine

Natural Sciences in General

Physics

2018-07-06

American Association for the Advancement of Science (AAAS)

0036-8075

1095-9203

Biology

Chemistry and Pharmacology

Geosciences

Computer Science

Medicine

Natural Sciences in General

Physics

Anthropology, Genetics

2018-07-10

American Heart Association (AHA)

1942-325X

1942-3268

Medicine

Atrial Fibrillation, Genetics, Cardiomyopathy

1089-7550

AIP Digital Archive

Physics

A three-dimensional calculation of Cherenkov-type frequency doubling in an optical channel waveguide is implemented by slicing the lateral profile of the interacting fields into a number of small segments. In each segment, lateral field variations of the harmonic signal are neglected. This method is more simple and requires less computational effort in comparison with a direct three-dimensional beam simulation. With the unidirectional-radiation model one can predict an optimum configuration and the conversion efficiency of miniaturized frequency doublers that utilize guided–to–radiation-mode interactions in nonlinear channel waveguides. Typical results are shown for blue-light generation through frequency doubling in a proton-exchanged MgO-doped lithium niobate channel waveguide. Analyses of green-light generation in organic channel waveguides are reported as well.

Electronic Resource

1089-7550

AIP Digital Archive

Physics

A useful wave-optics solution is derived for the Cerenkov mode calculation of optical third-harmonic signals that are generated in a multilayer planar optical waveguide. With this modal solution, the ultimate performance of the planar-configuration frequency tripler, being phase matched in the form of coherent Cerenkov radiation, is predictable. Numerical results are shown for the third-harmonic ultraviolet light generation in a planar glass waveguide loaded by a polydiacetylene Langmuir–Blodgett deposited thin film. Furthermore, the possibility of pronounced activation of the third-harmonic radiation from a glass waveguide pumped by an intense laser beam is suggested through field calculations based on a laser-induced damage model. In addition, loss analysis that includes both one- and two-photon absorptions is made by means of a phenomenological propagation model using coupled rate equations.

Electronic Resource

1600-0536

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

In order to investigate the el led of occlusion on the skin, the flexor sides of both upper arms were covered with column-shaped closed chambers, 30 mm in outer diameter. 20 mm in inner diameter. and 5 mm in height, which were made of polyethylene loam. The tops of the chambers were sealed be plastic films with various levels of water vapor permeability to control moisture in each chamber. The raised chamber walls prevented direct contact between the skin and the plastic film. After 24 h of application, morphological changes of the skin surface were observed microscopically by the nitrocellulose-replica method. Although no visual alterations were found on all areas of occluded skin, microscopic evaluation showed that simple occlusion by films induced an increase in the number of deepened skin furrows on the skin surface. This increase was associated with lower water vapor permeability of the films, as well as with higher values of both temperature and humidity on the test day. Thus, since conditions which facilitate perspiration from the skin lend to cause skin irritation, prolonged exposure of the skin to sweat by simple occlusion may act as a primary skin irritant

Electronic Resource

1460-9568

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

Hypocretins/orexins are neuropeptides implicated in sleep regulation and the sleep disorder narcolepsy. In order to examine how hypocretin activity fluctuates across 24 h with respect to the sleep–wake cycle, we measured changes in extracellular hypocretin-1 levels in the lateral hypothalamus and medial thalamus of freely moving rats with simultaneous sleep recordings. Hypocretin levels exhibited a robust diurnal fluctuation; levels slowly increased during the dark period (active phase), and decreased during the light period (rest phase). Levels were not correlated with the amount of wake or sleep in each period. Although an acute 4-h light-shift did not alter hypocretin levels, 6-h sleep deprivation significantly increased hypocretin release during the forced-wake period. Hypocretin activity is, thus, likely to build up during wakefulness and decline with the occurrence of sleep. These findings, together with the fact that a difficulty in maintaining wakefulness during the daytime is one of the primary symptoms of hypocretin-deficient narcolepsy, suggest that hypocretin activity may be critical in opposing sleep propensity during periods of prolonged wakefulness.

Electronic Resource

1365-2842

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

summary  The relative strengths of ceramic-to-metal and composite-to-metal bonds were compared after prolonged thermocycling. A total of 104 cast discs were produced from a gold alloy (Pontor LFC). A ceramic material (Duceragold) was fused to 24 discs to assess the strength of the metal–ceramic bond. An indirect composite material (New Metacolor Infis) was bonded to the remaining discs after surface preparation by Rocatec tribochemical coating, tin plating and priming with a phosphate conditioner [10-methacryloyloxydecyl dihydrogen phosphate (MDP), Cesead II], priming with a thione conditioner (V-Primer) or no treatment (unprimed control). Shear bond strengths were determined before and after thermocycling at 20 000 and 100 000 cycles. Pre-thermocycling bond strengths were ranked in the order: metal–ceramic (40·5 MPa); Rocatec treatment (33·1 MPa) and tin plating–MDP (31·0 MPa); V-Primer (20·9 MPa); and control (11·9 MPa). The bond strengths of the first three groups were not significantly different after 20 000 thermocycles, whereas those of the V-Primer and control groups were significantly reduced. After extended thermocycling (100 000 cycles) the metal–ceramic group had the highest mean shear bond strength (28·5 MPa; P 〈 0·05), followed by the Rocatec (23·9 MPa) and tin plating–MDP (22·1 MPa) groups. The metal–ceramic bond was the most durable, although its strength was reduced by 29·6% after extended thermocycling. On the basis of these results, we recommend the Rocatec and tin plating–MDP systems for composite-to-metal bonding. Metal–ceramic bonding, however, is superior to metal–composite bonding within the limitation of the current experiment.

Electronic Resource

1365-2842

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

summary  The purpose of the current study was to evaluate the bonding characteristics of super-elastic titanium–nickel (Ti–Ni) alloy castings. Disk specimens were cast from a Ti–Ni alloy (Ti-50·85Ni mol%) using an arc centrifugal casting machine. High-purity titanium and nickel specimens were also prepared as experimental references. The specimens were air-abraded with alumina, and bonded with an adhesive resin (Super-Bond C & B). A metal conditioner containing a phosphate monomer (Cesead II Opaque Primer) was also used for priming the specimens. Post-thermocycling average bond strengths (MPa) of the primed groups were 41·5 for Ti–Ni, 30·4 for Ti and 19·5 for Ni, whereas those of the unprimed groups were 21·6 for Ti, 19·3 for Ti–Ni and 9·3 for Ni. Application of the phosphate conditioner elevated the bond strengths of all alloy/metals (P 〈 0·05). X-ray fluorescence analysis revealed that nickel was attached to the debonded resin surface of the resin-to-nickel bonded specimen, indicating that corrosion of high-purity nickel occurred at the resin–nickel interface. Durable bonding to super-elastic Ti–Ni alloy castings can be achieved with a combination of a phosphate metal conditioner and a tri-n-butylborane-initiated adhesive resin.

Electronic Resource

1365-2842

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

summary  The purpose of this study was to evaluate the influence of visible-light exposure on water absorption, solubility and colour stability of dual-curable luting composites. Using eight dual-curable luting composites (2bond2, Bistite II, G-Cera Cosmotech II, Imperva Dual, Linkmax, Lute-It, Panavia Fluoro Cement and Variolink II), disk specimens were prepared by the following two methods: (i) dual-cured specimens; exposed with visible-light from a light-curing unit, and (ii) chemical-cured specimens; chemically polymerized without exposure. Five specimens were produced for each material and curing mode. Water absorption and solubility were determined according to standardized testing methods, and the data were compared using analysis of variance (anova) and contrasts. With regard to colour stability, the colour difference (ΔE*) values between 24 h and the other immersion periods (1, 2, 3, 4, 8, 12, 16, 20 and 24 weeks) were calculated and then analysed by repeated measure anova. The dual-cured specimens exhibited significantly lower solubility values than the chemical-cured specimens except for the Lute-It material. The dual-cured Linkmax material exhibited the lowest solubility (0·51 ± 0·01 μg mm−3) and the lowest ΔE* value after 24 weeks (2·64 ± 0·39). The dual-curable luting composites should be light-exposed after seating of restorations in order to reduce water absorption and solubility, and to improve colour stability.

Electronic Resource

1365-2842

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

Summary The purpose of the current study was to evaluate the bond strength and durability of two metal adhesive systems bonded to a silver–palladium–copper–gold (Ag–Pd) alloy. Disk specimens were cast from an Ag–Pd alloy (Castwell M.C. 12), air-abraded with 50 μm grain-sized alumina, and they were bonded with two primer-cement bonding systems (Alloy Primer and Panavia Fluoro Cement; Metaltite and Bistite II). For each cement, unprimed specimens were also prepared as experimental controls. Shear bond strengths were determined both before and after thermocycling (4–60 °C, 1 min each, 100 000 cycles). The average post-thermocycling bond strengths in MPa (n=8) were: 39·0 for the Metaltite–Bistite II system, 32·2 for the Alloy Primer–Panavia Fluoro Cement system, 23·1 for the Bistite II material and 21·0 for the Panavia Fluoro Cement material. The use of proprietary primers, both of which contain thione functional monomer, enhanced the post-thermocycling bond strengths of both cements (P 〈 0·05). After thermocycling, however, the difference in bond strength between the two cements was not significant regardless of the use of the primers (P 〉 0·05). It is concluded that the combined use of the thione primer and the luting agent is necessary for bonding the Ag–Pd alloy examined.

Electronic Resource

1365-2842

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

The purpose of this study was to evaluate the effects of disinfectants on the bond strength of resin to dentine. The surface of bovine dentine was exposed to formaldehyde (FA) aqueous solutions, glutaraldehyde (GA) aqueous solutions, 2-hydroxyethyl methacrylate aqueous solutions (HEMA), a commercially available dentine primer (Gluma CPS desensitizer, GLUMA), isotonic sodium chloride solution (IS), and distilled water (DW), and placed in a humidor (HU) at 37 °C, or non-stored (baseline). All dentine surfaces were conditioned with a 10% citric acid and 3% ferric chloride solution (10-3 liquid), and then bonded to an acrylic rod with a self-curing adhesive resin (Super-Bond C&B). The mean tensile bond strengths determined 24 h after bonding were compared by analysis of variance (ANOVA) and Fisher's protected LSD test (n=5, P ≤ 0·05). The exposure of dentine to IS, DW and HU for both 48 and 168 h resulted in a decrease in bond strength when compared with the baseline. The highest bond strengths after 168 h of exposure were obtained with 5% GA, 10% HEMA, and GLUMA, the values of which were equivalent to baseline and were significantly higher than that of FA. It is concluded that disinfectant pre-treatment with 5% GA or GLUMA stabilizes the bonding of tri-n-butylborane (TBB) initiated luting agent to bovine dentine conditioned with 10-3 liquid.

Electronic Resource

1365-2842

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

This study determined the bond strengths of porcelain bonding systems joined to a ceramic material, with the aim of evaluating the effect of a catalyst for silane coupling as well as that of initiators for bonding agents. Two sizes of specimen were cut from ceramic blocks (Cerec 2 Vitablocs Mark II®) and then primed with either a three-liquid self-curing bonding agent (Clearfil Porcelain Bond®, CPB), a three-liquid dual-activated bonding agent (Clapearl Bonding Agent®, CBA), or their components. Unprimed specimens were also used as controls. After conditioning, the two different sized plates were bonded together with a dual-cured luting agent (Clapearl DC®). The specimens were stored in 37 °C water for 24 h and shear bond strengths were determined. Shear testing revealed that the greatest bond strength was generated in the group consisting of ceramic material primed with CBA and exposed for 20 s prior to luting. Bond strengths of the CPB-primed group and the CBA-primed group without pre-exposure were comparable, whereas the remaining groups resulted in significantly lower bond strengths than the other three groups. The priming effect was greatly enhanced when a catalyst was used with the silane coupler as compared with the application of silane alone. The results suggest that incorporation of an initiator and a catalyst for silane coupling into the bonding agent reciprocally enhances bonding between the luting agent and the ceramic material.

Electronic Resource

1365-2842

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

The current study investigates the influence of three dentin hypersensitivity treating agents (Gluma CPS, MS Coat and Saforide) on bond strength to dentin of two luting agents (Panavia Fluoro Cement and Super-Bond C & B). Sixty bovine dentin substrates were divided into 12 combinations of four treatment conditions (Gluma CPS, MS Coat, Saforide and control) and three adhesive systems (AD Gel sodium hypochlorite + Panavia Fluoro Cement, Panavia Fluoro Cement without AD Gel and Super-Bond C & B). After bonding the treated teeth to steel rods, 24-h tensile bond strengths were determined, and average values (n=5) were compared by analysis of variance (ANOVA). Without application of the desensitizers, bond strengths of the two groups (Super-Bond C & B, 10·2 MPa; AD Gel + Panavia, 11·5 MPa) were comparable, and they were greater than the group bonded with the Panavia material with no AD Gel conditioning (7·1 MPa). Application of the Saforide ammoniated silver fluoride desensitizer reduced bond strength of both the Super-Bond and Panavia luting agents, whereas the MS Coat polymeric agent negatively affected bond strength of the Panavia cement only. The use of the Gluma desensitizer did not affect bond strength of any of the three adhesive systems, and the bond strength of the Panavia cement with the AD Gel conditioning was not reduced by application of any of the three desensitizers. The four combinations of two desensitizers (MS Coat and Gluma CPS) and two adhesive systems (Super-Bond C & B and AD Gel + Panavia) are deemed to be applicable to fixed prosthodontic treatment.

Electronic Resource

1365-2842

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

summary  The purpose of the current study was to evaluate the effect of two-component ceramic primers on the bond strength of a composite material joined to a sintered porcelain material. Two sizes of porcelain discs (VMK 68; 10 and 8 mm in diameter by 2·5 mm thick) were ground (No. 1000 SiC), and surface-conditioned using one of the following systems: (i) unprimed, (ii) Liquid A of the Porcelain Liner M material (PLM-A), (iii) Liquid B of Porcelain Liner M (PLM-B), (iv) Liquids A and B of Porcelain Liner M (PLM-AB), (v) Liquid A of the Tokuso Ceramics Primer material (TCP-A), (vi) Liquid B of Tokuso Ceramics Primer (TCP-B) and (vii) Liquids A and B of Tokuso Ceramics Primer (TCP-AB). All specimens were bonded with the Bistite II dual-cured composite luting agent, and shear bond strengths were determined both after 24 h immersion in water and after subsequent thermocycling (4–60 °C, 1 min each, 20 000 cycles). Of the seven groups assessed, two groups (PLM-AB and TCP-AB) showed the greatest bond strength both before (30·7 MPa for PLM-AB and 29·7 MPa for TCP-AB) and after (19·7 MPa for PLM-AB and 22·4 MPa for TCP-AB) thermocycling (P 〈 0·05). No significant differences were found between the PLM-AB and TCP-AB groups regardless of the application of thermocycling (P 〉 0·05). It can be concluded that both of the acid-catalysed two-liquid ceramic primers showed superior bonding to the unhydrolysed single-liquid silane agents (PLM-B and TCP-A) when the feldspathic porcelain was bonded with the Bistite II luting composite.

Electronic Resource

1365-2842

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

The purpose of the current study was to evaluate the bond strength of a metal adhesive system bonded to stainless steels and their component metals. Two sizes of disk specimens (10 and 8 mm in diameter×2·5 mm thickness) were machined from two stainless steels designed for magnetic attachment (AUM20 and SUS 316L), as well as from high-purity chromium (Cr) and nickel (Ni) metals for reference. The specimens were air-abraded with alumina, either primed with a metal conditioner (Cesead II Opaque Primer) or left unprimed, and bonded with an adhesive resin (Super-Bond Opaque). Shear bond strengths were determined before and after thermocycling, and the results were analysed by analysis of variance (anova). Post-thermocycling bond strengths of the unprimed groups were 16·3 MPa for the AUM20 alloy, 7·5 MPa for the SUS 316L alloy, 31·1 MPa for Cr and 3·1 MPa for Ni. Those of the conditioned groups were 30·3 MPa for the AUM20 alloy, 32·9 MPa for the SUS 316L alloy, 39·3 MPa for Cr and 13·1 MPa for Ni. Application of the conditioner elevated the bond strengths of all groups (P〈0·05). It can be concluded that combined use of the conditioner and the Super-Bond adhesive is effective for bonding the stainless steels examined, and that Cr is a suitable component for the bonding system in question.

Electronic Resource

1365-2842

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

This study examined depth of cure of two prosthetic composite materials (Artglass® and Dentacolor®) polymerized by means of four photo-curing units for the purpose of comparing the curing performance of laboratory and handheld curing units. Each composite material was photo-exposed either with one of two laboratory photo-curing units (Dentacolor XS® and UniXS®) or with one of two handheld photo-curing units (Translux CL® and Translux EC®). The light sources were differently shaped xenon stroboscopic lamps for the laboratory units, and halogen lamps of differing intensity for the handheld units. Exposure periods were 20, 30, 60, and 90 s, and depth of cure of the materials was determined with a scraping technique. The two handheld curing units generated significantly greater depth of cure for both materials than either of the two laboratory curing units. Of the two laboratory units, the Dentacolor XS® unit produced somewhat greater depth of cure for all combinations than the UniXS® unit, whereas the differences in depth of cure of the two materials exposed with the two handheld units were not significant when the exposure time period was 60 s or more. The Dentacolor® composite generally demonstrated greater depth of cure than the Artglass® composite under identical curing conditions.

Electronic Resource

1365-2842

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

The purpose of the current study was to evaluate the clinical performance of a chemically cured denture relining material after 1-year service period. A powder–liquid material designed for denture base relining (Tokuso Rebase Normal-set, Tokuyama Corp., Tokyo, Japan.) was assessed. Fifty adult patients, who required denture reline treatment, participated in the current project. Adaptation of each denture was examined with a silicone elastomeric material, and the surface to be relined was reduced by means of a rotary cutting instrument, then conditioned with dichloromethane. The relining material was spatulated, poured into the relining area, inserted and adjusted after setting. Each relined denture was subjected to base line evaluation immediately after relining and end evaluation after 1 year. Standardized criteria were used for direct evaluation of the material. After an observation period of 1 year, the rate of the relining cases considered to be in clinically ideal condition (Alfa) was 90% for staining, 90% for discoloration, 94% for peeling, 96% for adaptation and 100% for irritation to oral tissue. Only one case was judged as clinically unacceptable (Charlie), and this was for staining. On the basis of a 1-year observation, the Tokuso Rebase material is considered to be a clinically reliable hard denture relining agent.

Electronic Resource

1365-2842

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

This study examined curing depth of eight prosthetic composite materials polymerized by means of six photo-curing units for the purpose of evaluating the curing performance of material-curing unit combinations. Each composite material was exposed with a photo-curing unit recommended by the manufacturer. The light sources of the units were halogen/fluorescent, xenon, metal halide, fluorescent, and halogen lamps, and exposure periods were 20, 30, 60, and 90 s. Curing depth of the materials was determined according to the method described by the International Organization for Standardization (ISO 4049). The results were analysed by factorial analysis of variance ( anova) and multiple comparison intervals. Two-factor anova revealed that the depth of cure was influenced both by the material-unit combination and by the exposure period (P=0·0001). Among the eight combinations, a hybrid composite material (Prywood color®) polymerized with a metal halide curing unit (Hyper LII®) exhibited the greatest depth of cure after 90-s exposure. For all combinations, longer exposure increased the depth of cure.

Electronic Resource

1365-2842

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

summary Adhesive bonding of titanium was investigated with the use of five primers and two luting agents. All of the primers contained acidic methacrylate monomers for promotion of metal bonding. Titanium metal specimens were bonded with seven combinations of five primers and two luting agents. Durability of the bond was evaluated by means of thermocycling. Although all five primers enhanced the bond strength to titanium, three of the primers (Super-Bond Liquid, Metal Primer and Tokuso Rebase MR. Bond) demonstrated more durable bonds than the other two primers (Acryl Bond and All-Bond 2 Primer B). The tri-n-butylborane (TBB)-initiated luting agent exhibited better bonding ability as compared to conventional composite resin. The strongest and the most consistent bond was achieved by the combination of 4-methacryloyloxyethyl trimellitate anhydride (4-META) primer and TBB resin.

Electronic Resource