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Deuterated drugs are valuable in the fields of drug discovery and medicinal chemistry. 2′,3′,5′,5″-tetradeuterated uridine derivatives were synthesised from 2,3,5,5′-selectively tetradeuterated ribose using Sajiki's H–D exchanged Ru/C–H2–D2O–NaOH system and silyl–Hilbert–Johnson methods. The total deuterium content of the tetradeuterated uridines was over 92% using either basic or acidic reaction conditions. These derivatives would be expected as building blocks for the synthesis of deuterium-substituted nucleic acid probes for tracking the pharmacokinetics of nucleic acid drugs. [ABSTRACT FROM AUTHOR]

Dissolved N2O is occasionally detected in surface and ground water in rice paddy fields, whereas little or no N2O is emitted to the atmosphere above these fields. This indicates the occurrence of N2O reduction in rice paddy fields; however, identity of the N2O reducers is largely unknown. In this study, we employed both culture-dependent and culture-independent approaches to identify N2O reducers in rice paddy soil. In a soil microcosm, N2O and succinate were added as the electron acceptor and donor, respectively, for N2O reduction. For the stable isotope probing (SIP) experiment, 13C-labeled succinate was used to identify succinate-assimilating microbes under N2O-reducing conditions. DNA was extracted 24 h after incubation, and heavy and light DNA fractions were separated by density gradient ultracentrifugation. Denaturing gradient gel electrophoresis and clone library analysis targeting the 16S rRNA and the N2O reductase gene were performed. For culture-dependent analysis, the microbes that elongated under N2O-reducing conditions in the presence of cell-division inhibitors were individually captured by a micromanipulator and transferred to a low-nutrient medium. The N2O-reducing ability of these strains was examined by gas chromatography/mass spectrometry. Results of the SIP analysis suggested that Burkholderiales and Rhodospirillales bacteria dominated the population under N2O-reducing conditions, in contrast to the control sample (soil incubated with only 13C-succinate). Results of the single-cell isolation technique also indicated that the majority of the N2O-reducing strains belonged to the genera Herbaspirillum (Burkholderiales) and Azospirillum (Rhodospirillales). In addition, Herbaspirillum strains reduced N2O faster than Azospirillum strains. These results suggest that Herbaspirillum spp. may have an important role in N2O reduction in rice paddy soils. [ABSTRACT FROM AUTHOR]

Finely powdered enamel was used to develop a prosthetic resin composite that has good mechanical properties and no potential to abrade opposing tooth structure. Bovine teeth were ground into powder and then the enamel particles were separated from the powder by centrifugation in bromoform–ethanol solution. The resin matrix consisted of UDMA (60 mole %) and Tri-EDMA (40 mole %). Camphorquinone (0.5 mass %) was added to the monomer as a photo-initiator. Fillers were incorporated directly into the resin matrix in amounts of 80 or 85 mass %. The flexural strength and Vickers hardness (Hv) were measured. The average flexural strength and Hv values for specimens having 85 mass % filler that had been subjected to heat treatment at 100°C after light-curing were 95.2 and 109.8 MPa, respectively, which are higher than those for most commercial prosthetic resin composites. These findings suggest that a novel prosthetic resin composite with good mechanical properties can be made by loading finely powdered enamel into the resin matrix. [ABSTRACT FROM AUTHOR]

A novel type of copolymer gel bearing the sulfo group was developed as a heterogeneous acid catalyst for the solvent free acetalization of glycerol with acetone to form a desirable solketal, as well as the solvent free esterification of oleic acid with ethanol to form ethyl oleate as a biodiesel fuel. The copolymer gels were synthesized by the copolymerization of a primary monomer (ethoxy diethyleneglycol acrylate (EDGA), N-isopropylacrylamide (NIPA), etc.) with 2-acrylamido-2-methyl-1-propanesulfonic acid (AMPS). The copolymer gels, such as EDGA- co -AMPS gel and NIPA- co -AMPS gel, successfully catalyzed both reactions with a higher reaction rate than those of AMPS gel and the conventional sulfonic ion exchange resin (Amberlyst). According to Le Chatelier's principle, if a gel catalyst absorbs reactants well, and expels or poorly absorbs products, the apparent rate of the reaction occurring within the gel is enhanced. This hypothesis was examined by analyzing the solution absorptions of these gels and their reaction rates, including Eley–Rideal kinetic analysis. [Display omitted] • A novel type of copolymer gel bearing a sulfo group has been developed. • Copolymer gels catalyzed glycerol acetalization and oleic acid esterification. • The acetalization reaction rate was analyzed using the Eley–Rideal kinetic model. • Their solution absorptions influenced their catalytic activities. [ABSTRACT FROM AUTHOR]

Objective. The purpose of this study was to improve adhesion between dental adhesive resins and 14K gold alloy by creating a sponge-like structure on the alloy surface which enhanced mechanical bonding.Methods. The internal oxidation particles of Cu oxides precipitated on a 14K gold alloy surface after high-temperature oxidation at 800 °C in air were removed by pickling with an acid solution to create a sponge-like structure on the alloy surface. A PMMA resin containing 4-META as an adhesive monomer and a self-cured resin without 4-META were used to examine the effects of mechanical and chemical factors on bond strength. A thiophosphate-type metal primer (M-Primer II) was used in combination with 4-META resin to strengthen the chemical bonding of 4-META resin to the porous alloy surface. The surfaces of the alloy specimen treated by oxidation, pickling, and bonding with 4-META resin were analyzed using an electron probe X-ray micro-analyzer.Results. SEM observation showed many resin tags on the resin side of the bond structure after removal of the gold alloy matrix with aqua regia. The bond strength of 4-META resin to the porous alloy surface was 38±3 (mean±SD) MPa whereas that to a flat alloy surface with the same composition was 19±1 MPa. The bond strength of a self-cured resin without 4-META to the porous alloy surface was 24±2 MPa.Significance. A high bond strength was obtained when 4-META resin was bonded to the porous 14K gold alloy surface treated with M-Primer II. [Copyright &y& Elsevier]

Self-etching primer adhesives have recently been introduced to simplify bonding. However, the fundamental bonding mechanism of self-etching primers to enamel is not yet fully understood. This study aimed to investigate resin–enamel bonds of self-etching primer adhesives on ground enamel. Two self-etching primer adhesives (Clearfil Liner Bond 2 V and Clearfil SE Bond) were used in this study. A total-etch adhesive (One-Step) was used as a control. Resin–enamel beams were subjected to the microtensile bond test. Subsequently, the failure modes of all specimens were quantified using image analysis. Undemineralized and demineralized ultrathin sections of the resin–enamel bonded specimens were examined using transmission electron microscopy. The bond strengths of Clearfil SE Bond (39.8 ± 11.9 MPa) and One-Step (46.2 ± 12.7 MPa) were significantly greater than that of Clearfil Liner Bond 2V (30.4 ± 6.2 MPa). Scanning electron microscopy of the fractured surfaces revealed the failure direction and weakest portion within each bond. Transmission electron microscopy showed a thin hybridized complex of resin in enamel produced by the self-etching primers without the usual micrometer-sized resin tags seen in resin–enamel bonds produced using the total-etch adhesive. The morphological features of the resin–enamel bonds produced by two self-etching primers tested were different from that created with the total-etch adhesive. [ABSTRACT FROM AUTHOR]

Our knowledge of the mechanisms responsible for the degradation of resin–dentin bonds are poorly understood. This study investigated the degradation of resin–dentin bonds after 1 year immersion in water. Resin–dentin beams (adhesive area: 0.9 mm2) were made by bonding using a resin adhesive, to extracted human teeth. The experimental beams were stored in water for 1 year. Beams that had been stored in water for 24 h were used as controls. After water storage, the beams were subjected to microtensile bond testing. The dentin side of the fractured surface was observed using FE-SEM. Subsequently, these fractured beams were embedded in epoxy resin and examined by TEM. The bond strength of the control specimens (40.3±15.1 MPa) decreased significantly (p<0.01) after 1 year of water exposure (13.3±5.6 MPa). Loss of resin was observed within fractured hybrid layers in the 1 year specimens but not in the controls. Transmission electron microscopic examination revealed the presence of micromorphological alterations in the collagen fibrils after 1 year of water storage. These micromorphological changes (resin elution and alteration of the collagen fibrils) seem to be responsible for the bond degradation leading to bond strength reduction. [Copyright &y& Elsevier]

The corrosion and tarnish behavior of a dental casting Pd–25Ag–18Cu–12Au alloy in 0.1% Na2S solution at 37 °C was investigated using potentiodynamic polarization and spectrocolorimetric techniques. The surface film was characterized by X-ray photoelectron spectroscopy (XPS).This alloy exhibited markedly higher resistance to corrosion and tarnish than did the Ag–20Pd–18Cu–12Au alloy in current clinical use. XPS spectra indicated the presence of a thin sulphide film composed of PdS. It was found that the PdS film is very protective and is responsible for the passivity of the Pd–25Ag–18Cu–12Au alloy in 0.1% Na2S solution. [Copyright &y& Elsevier]

Aim: Portopulmonary hypertension (PoPH) is a well‐known complication of liver cirrhosis. The aim of this study was to clarify the pulmonary hemodynamics and the prevalence and characteristics of PoPH in patients with portal hypertension. Methods: The subjects were 335 patients with portal hypertension diagnosed by hepatic vein pressure gradient (HVPG). Among them, 186 patients received measurements of pulmonary artery pressure (PAP), pulmonary artery wedge pressure (PAWP) and pulmonary vascular resistance (PVR). PoPH was diagnosed by PAP >20 mmHg, PVR ≥3 Wood units (WU) and PAWP ≤15 mmHg. Results: The Child–Pugh classification was class A in 53, B in 92 and C in 41 patients. Median (range) values of HVPG, PAP, PVR and PAWP were 18.4 (5.5–39.0) mmHg, 12.9 (6.6–40.8) mmHg, 0.8 (0.1–4.5) WU and 7.5 (2.2–15.4) mmHg, respectively. Of six patients with PAP >20 mmHg, four had autoimmune hepatitis or primary biliary cholangitis, with the prevalence being significantly higher than that in patients with PAP ≤20 mmHg. Meanwhile, no significant difference was noted in the hepatic functional reserve or HVPG between patients with PAP >20 mmHg and ≤20 mmHg. Only two patients met the diagnostic criteria of PoPH and both patients were Child–Pugh B. The Child–Pugh score and HVPG were not associated with PoPH. Conclusions: Our study demonstrated that only two patients were complicated by PoPH. High PAP values were noted in patients with primary biliary cholangitis or autoimmune hepatitis. However, the presence of PoPH and high PAP were not associated with the degree of hepatic functional reserve or HVPG. [ABSTRACT FROM AUTHOR]

In this work, we investigate the effect of the material engineering on programming margin in the double-layered phase-change memory, which is the most important parameter for the stability of multilevel storage. Compared with the TiN/SbTeN cell, the TiSiN/GeSbTe double-layered cell exhibits the resistance ratio of the highest to lowest resistance levels up to two to three orders of magnitude, indicating much larger programming margin and thus higher stability and/or more available levels. Our calculation results show that the resistivities of the top heating layer and the phase-change layer have a significant effect on the programming margin. [ABSTRACT FROM AUTHOR]

Endo K, Hashimoto M, Haraguchi K, Ohno H. Crystal growth by restorative filling materials. Eur J Oral Sci 2010; 118: 489–493. © 2010 Eur J Oral Sci This study examined the activity and ability of materials to mineralize teeth in gaps, simulating microleakage between the materials and teeth. Three restorative materials (two glass ionomer cements and a compomer) were used in this study. Cured disks of restoratives were placed over flat human tooth surfaces (enamel and dentin), separated by a standardized 20-μm interfacial space, and stored in water for 24 h or 1 yr. After the water-storage period, the materials were detached from the teeth and the opposing surfaces were examined by scanning electron microscopy (SEM) and electron probe micro analysis (EPMA).Hemispherical-shaped precipitations, composed of minute semicircle plate-like crystals, were observed by SEM on the enamel surface after 1 yr of water storage for glass ionomer cement. The amount of crystal growth with the chemical-cured type of glass ionomer cement was greater than with the dual-cured type of glass ionomer cement. However, there was no crystal formation in the compomer. Moreover, no structural changes were observed on dentin surfaces for any material in water after 1 yr. The elements detected in the crystals by EPMA were calcium (Ca), phosphorus (P), and aluminum (Al). The two glass ionomer cements tested have the ability to induce crystals whose composition might be derived from cured glass ionomers. [ABSTRACT FROM AUTHOR]

Hashimoto M, Fujita S, Nagano F, Ohno H, Endo K. Ten-years degradation of resin–dentin bonds. Eur J Oral Sci 2010; 118: 404–410. © 2010 The Authors. Journal compilation © 2010 Eur J Oral Sci The purpose of this study was to evaluate the durability of resin–dentin bonds in 10-yr water-storage testing. Resin–dentin bonded bulk specimens were prepared using six commercially available resin adhesives. The resin–dentin bonded specimens were stored in water for 24 h (control group) or for 10 yr (experimental groups). After each storage period, the specimens were sectioned to make specimen beams and then subjected to a microtensile bond test. After the bond test, fractured surfaces were examined by scanning electron microscopy (SEM). In addition, interfacial observation of silver nanoleakage was performed using the backscatter electron mode of SEM. The bond strengths of four of the six adhesive systems tested decreased significantly after 10 yr. However, no significant bond-strength reduction was recorded for the other two systems. The interfacial observations showed water tree propagation in the bonding resin layer as a typical morphological change after aging for five of the six adhesives tested. Water tree propagation may be a symptom of degradation in the resin bonding layer of resin–dentin bonds. [ABSTRACT FROM AUTHOR]

Hashimoto M, Nagano F, Endo K, Ohno H. Measurements of volatile compound contents in resins using a moisture analyzer. Eur J Oral Sci 2010; 118: 94–99. © 2010 The Authors. Journal compilation© 2010 Eur J Oral Sci The contents of volatile adhesive compounds, such as water, solvents, and residual unpolymerized monomers, affect the integrity and durability of adhesive bonding. However, there is no method available that can be used to rapidly assess the residual solvent or water contents of adhesive resins. This study examined the effectiveness of a digital moisture analyzer to measure the volatile compound contents of resins. Five self-etching adhesives and seven experimental light-cured resins prepared with different contents (0, 10, and 20% by weight) of water or solvents (acetone and ethanol) were examined in this study. The resins were prepared using different methods (with and without air blast or light-curing) to simulate the clinical conditions of adhesive application. Resin weight changes (% of weight loss) were determined as the residual volatile compound contents, using the moisture analyzer. After the measurements, the resin films were examined using a scanning electron microscope. The weight changes of the resins were found to depend on the amount of water or solvents evaporating from the resin. Water and solvents were evaporated by air blast or light-curing, but some of the water and solvents remained in the cured resin. The moisture analyzer is easy to operate and is a useful instrument for using to measure the residual volatile compound contents of adhesive resin. [ABSTRACT FROM AUTHOR]

The purpose of this study was to evaluate the durability of one-bottle self-etching adhesive during long-term water-storage testing. Resin–dentin bonded specimens were prepared using four commercially available one-bottle self-etching adhesives. The specimens were sectioned perpendicular to the adhesive interface to produce beam-shaped specimens that were stored in water for 24 h (control group) and 100, 200, and 300 d (experimental groups). After each storage period, the beams were subjected to a microtensile bond test. After the bond test, fractured surfaces were examined using a scanning electron microscope. In addition, interfacial observations of the silver tracer were performed using the secondary and back-scatter modes of the scanning electron microscope. The bond strength of all tested adhesives decreased significantly after 100 or more days in water. The interfacial observations showed an oxygen-inhibition zone as electron lucent in the adhesive–composite border in control specimens, displaying silver impregnation with breakage after aging. The deterioration of the oxygen-inhibition zone in the adhesive–resin composite junction resulted in a decrease in bond strength after 100 d in water for one-bottle self-etching adhesives. [ABSTRACT FROM AUTHOR]

Abstract: Objective: The purpose of this study was to investigate the metallurgical phases in beta–titanium soldered joints prepared by infrared soldering, using the Micro X-ray diffraction technique (Micro-XRD), and to characterize the Vickers hardness in the soldered beta–titanium wires. Methods: Beta–titanium wires with cross-section dimensions of 0.032in.×0.032in. (TMA, Ormco), and both titanium-based solder (Ti-30Ni-20Cu, Selec) and silver-based solder (Ag-22Cu-17Zn-5Sn, Tomy) were selected. Soldering was performed using infrared radiation (RS-1, Morita) under argon atmosphere. Micro-XRD analyses were performed at room temperature. Micro-XRD spectra were obtained for the boundary region of the soldered beta–titanium wires using 50μm and 10μm diameter analysis regions. Hardness was measured at 30μm intervals from boundary of the diffusion layer and beta–titanium wire. The Kruskal–Wallis test with the Bonferroni and Wilcoxson Mann–Whitney tests for nonparametric means were employed as statistical methods (P <0.05). Results: For both types of soldered beta–titanium samples, the Micro-XRD spectra contained four major peaks for body-centered cubic (bcc) beta–titanium. Additional peaks at about 41 and 45 degrees are attributed to Cu–Ti intermetallic phase(s), which may be metastable under soldering conditions. The diffusion layer had greater hardness than bulk beta–titanium for both types of soldered specimens (P <0.05). Significance: Soldering of beta–titanium orthodontic wire by infrared radiation may be acceptable for clinical use, since Micro-XRD spectra revealed that both types of soldered specimens largely retained the bcc beta–titanium structure. Further research is needed to investigate the mechanical properties and corrosion behavior of infrared-soldered beta–titanium wire. [Copyright &y& Elsevier]

Although anti-Fcγ receptor antibodies (Abs) are detected in various autoimmune diseases, there have been no studies about the anti-Fcγ receptor Abs in alopecia areata (AA). To detect the anti-Fcγ receptor Abs in patients with AA and their clinical correlations, Serum samples from 72 patients with AA and 23 normal controls were examined by enzyme-linked immunosorbent assay assessing anti-Fcγ receptor Ab levels. Anti-Fcγ receptor I Abs were significantly frequently detected in patients with AA compared with normal controls. Furthermore, the detection of anti-Fcγ receptor I Abs significantly inversely correlated with the disease duration. These results suggest that anti-Fcγ receptor I Ab and Fcγ receptor I play an important role in the regulation of AA, are useful for a marker of the disease prognosis and are worth intense research for the reasonable and specific therapy of AA. [ABSTRACT FROM AUTHOR]

The purpose of this study was to establish a novel method for evaluating orthodontic tooth movement in three-dimensional (3-D) space. The present system consisted of the following procedures at a given treatment period: (1) 3-D tooth positions were measured with a 3-D surface-scanning system using a slit laser beam; (2) the 3-D shape data were registered automatically at the maxillary first molars, and the coordinate systems were normalized; (3) the rotation matrix and translation vector were calculated from the automatic registration of the two position data for a given tooth; (4) the finite helical axes of teeth were calculated as the locus of zero rotational displacement; and (5) tooth movement was presented as rotation about and translation along the finite helical axis. To test this system, a male patient (age 22 yr 2 months) with Angle Class III malocclusion and moderate crowding of the anterior teeth, who had been treated using a standard multi-bracket appliance, was used as a model case in this study. Impressions for a dental cast model were taken at five phases; immediately before and after application of the appliance, and 10 days, 1 month and 2 months after beginning treatment. The results demonstrated that the present analytical method can more simply describe the movement of a given tooth by rotation about and translation along the finite helical axis, and provides quantitative visual 3-D information on complicated tooth movement during orthodontic treatment. [Copyright &y& Elsevier]