A simple plasma spraying method was employed in coating hydroxyapaptite (HA) on to carbon/carbon composites (C/C composites). The morphology of the coating was examined under scanning electron microscope (SEM). The phase constitutions of the HA coating were determined by X-ray diffractometer (XRD). The shear strength of the HA coating-C/C composite substrates was detected. A hydroxyapatite coating with rough surface was observed. A considerable amount of amorphous phase appeared as a result from the coating process, which could be transformed into the morphous phase crystalline HA after subsequent heat treatment. The shear strength between the HA coating and C/C composite substrates was 7.15 MPa.
Bone Substitutes ; chemistry ; Carbon ; chemistry ; Carbon Compounds, Inorganic ; chemistry ; Coated Materials, Biocompatible ; chemistry ; Durapatite ; pharmacology ; Humans

STATEMENT OF PROBLEMS: Self-etch adhesives exhibit some clinical benefits such as ease of manipulation and reduced technique-sensitivity. Nevertheless, some concern remains regarding the bonding effectiveness of self-etch adhesives to enamel, in particular when so-called 'mild'self-etch adhesives are employed. This study compared the microtensile bond strengths to ground enamel of the two-step self-etch adhesive Clearfil SE Bond (Kuraray) to the three-step etchand-rinse adhesive Scotchbond Multi-Purpose (3M ESPE) and the one-step self-etch adhesive iBond (Heraeus Kulzer). PURPOSE: The purpose of this study was to determine the effect of a preceding phosphoric acid conditioning step on the bonding effectiveness of a two-step self-etch adhesive to ground enamel. MATERIAL AND METHODS: The two-step self-etch adhesive Clearfil SE Bond non-etch group, Clearfil SE Bond etch group with prior 35% phosphoric acid etching, and the one-step self-etch adhesive iBond group were used as experimental groups. The three-step etch-and-rinse adhesive Scotchbond Multi-Purpose was used as a control group. The facial surfaces of bovine incisors were divided in four equal parts cruciformly, and randomly distributed into each group. The facial surface of each incisor was ground with 800-grit silicon carbide paper. Each adhesive group was applied according to the manufacturer's instructions to ground enamel, after which the surface was built up using Light-Core (Bisco). After storage in distilled water at 37 degreesC for 1 week, the restored teeth were sectioned into enamel beams approximately 0.8*0.8mm in cross section using a low speed precision diamond saw (TOPMET Metsaw-LS). After storage in distilled water at 37 degreesC for 1 month, 3 months, microtensile bond strength evaluations were performed using microspecimens. The microtensile bond strength (MPa) was derived by dividing the imposed force (N) at time of fracture by the bond area (mm(2)). The mode of failure at the interface was determined with a microscope (Microscope-B nocular, Nikon). The data of microtensile bond strength were statistically analyzed using a one-way ANOVA, followed by Least Significant Difference Post Hoc Test at a significance level of 5%. Results: The mean microtensile bond strength after 1 month of storage showed no statistically significant difference between all adhesive groups (P>0.05). After 3 months of storage, adhesion to ground enamel of iBond was not significantly different from Clearfil SE Bond etch (P>0.05), while Clearfil SE Bond non-etch and Scotchbond Multi-Purpose demonstrated significantly lower bond strengths (P<0.05), with no significant differences between the two adhesives. CONCLUSION: In this study the microtensile bond strength to ground enamel of two-step selfetch adhesive Clearfil SE Bond was not significantly different from three-step etch-and-rinse adhesive Scotchbond Multi-Purpose, and prior etching with 35% phosphoric acid significantly increased the bonding effectiveness of Clearfil SE Bond to enamel at 3 months.
Adhesives ; Carbon Compounds, Inorganic ; Dental Enamel ; Dentin ; Diamond ; Incisor ; Phosphoric Acids ; Resin Cements ; Silicon Compounds ; Tooth ; Water

PURPOSE: To evaluate the effects of hydrofluoric acid etching and Er,Cr:YSGG laser irradiation on the shear bond strength of resin cement to lithium disilicate ceramic. MATERIALS AND METHODS: Fifty-five ceramic blocks (5 mm x 5 mm x 2 mm) were fabricated and embedded in acrylic resin. Their surfaces were finished with 1000-grit silicon carbide paper. The blocks were assigned to five groups: 1) 9.5% hydrofluoric-acid etching for 60 s; 2-4), 1.5-, 2.5-, and 6-W Er,Cr:YSGG laser applications for 60 seconds, respectively; and 5) no treatment (control). One specimen from each group was examined using scanning electron microscopy. Ceramic primer (Rely X ceramic primer) and adhesive (Adper Single Bond) were applied to the ceramic surfaces, followed by resin cement to bond the composite cylinders, and light curing. Bonded specimens were stored in distilled water at 37degrees C for 24 hours. Shear bond strengths were determined by a universal testing machine at 1 mm/min crosshead speed. Data were analyzed using Kruskal-Wallis and Mann-Whitney U-tests (alpha=0.05). RESULTS: Adhesion was significantly stronger in Group 2 (3.88 +/- 1.94 MPa) and Group 3 (3.65 +/- 1.87 MPa) than in Control group (1.95 +/- 1.06 MPa), in which bonding values were lowest (P<.01). No significant difference was observed between Group 4 (3.59 +/- 1.19 MPa) and Control group. Shear bond strength was highest in Group 1 (8.42 +/- 1.86 MPa; P<.01). CONCLUSION: Er,Cr:YSGG laser irradiation at 1.5 and 2.5 W increased shear bond strengths between ceramic and resin cement compared with untreated ceramic surfaces. Irradiation at 6 W may not be an efficient ceramic surface treatment technique.
Adhesives ; Carbon Compounds, Inorganic ; Ceramics ; Collodion ; Dental Porcelain ; Hydrofluoric Acid ; Light ; Lithium ; Microscopy, Electron, Scanning ; Resin Cements ; Silicon Compounds ; Water

The hardness, compressive strength and cure depth are important indices of the composite resin. This investigation was made with regard to the effects of silicon carbide on the cure depth, hardness and compressive strength of the light-curing composite resin. Different amounts of silicon carbide were added to the light-curing composite resin, which accounted for 0 wt%, 1 wt%, 0.6 wt%, 0.3 wt%, 0.1 wt%, 0.05 wt% and 0.005 wt% of the composite resin, respectively. The hardness, compressive strength and cure depth of the six afore-mentioned groups of composite resin were measured by the vernier caliper, the vickers hardness tester and the tensile strength of machine, respectively. The results showed that silicon carbide improved the hardness and compressive strength of the light-curing composite resin,when the concentration was 0.05 wt%. And the cure depth was close to that of control.
Carbon Compounds, Inorganic ; pharmacology ; Composite Resins ; chemistry ; Compressive Strength ; drug effects ; Dental Materials ; chemistry ; Hardness ; drug effects ; Silicon Compounds ; pharmacology

Study of geometries of 16 possible isomers for C76N2 based on C78(C2v) by intermediate neglect of differential overlap (INDO) series of methods indicated that the most stable geometry 25,78-C76N2 where two nitrogen atoms substitute two apexes C25 and C78 near the shortest X axis and Y axis formed by two hexagons and a pentagon. Electronic structures and spectra of C76N2 were investigated. The reason for the red-shift for absorptions of C76N2 compared with that of C78(C2v) is discussed.
Carbon Compounds, Inorganic ; analysis ; chemistry ; Computer Simulation ; Electronics ; Electrons ; Isomerism ; Models, Chemical ; Models, Molecular ; Nitrogen Compounds ; analysis ; chemistry ; Spectrum Analysis ; methods

Silicon carbide (SiC) ceramic with YAG (Y3Al5O12) additive added by sol-gel method was liquid-phase sintered at different sintering temperatures, and the sintering mechanism and microstructural characteristics of resulting silicon carbide ceramics were analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM) and elemental distribution of surface (EDS). YAG (yttrium aluminum garnet) phase formed before the sintering and its uniform distribution in the SiC/YAG composite powder decreased the sintering temperature and improved the densification of SiC ceramic. The suitable sintering temperature was 1860 degrees C with the specimen sintered at this temperature having superior sintering and mechanical properties, smaller crystal size and fewer microstructure defects. Three characteristics of improved toughness of SiC ceramic with YAG added by sol-gel method were microstructural densification, main-crack deflection and crystal 'bridging'.
Aluminum Oxide ; analysis ; chemistry ; Carbon Compounds, Inorganic ; analysis ; chemistry ; Ceramics ; chemistry ; Crystallization ; methods ; Gels ; chemistry ; Hot Temperature ; Molecular Conformation ; Phase Transition ; Silicon Compounds ; analysis ; chemistry ; Surface Properties ; Yttrium ; analysis ; chemistry

Carbon dioxide (CO2) poisoning is rare, but its clinical features of acute exposure include cardiovascular, respiratory, neurologic and metabolic aspects. CO2 can also have a direct toxicological effect. At very high concentrations (>9%), CO2 induces respiratory depression and narcotic-like effects on the central nervous system. Especially, acute poisoning from dry ice is caused by CO2 gas inhalation and asphyxiation, and may impose excess load on the myocardium. This case was an acute CO2 poisoning from dry ice gas inhalation. In spite of an initial severe status, the male patient rapidly improved with no complications following the application of highly concentrated oxygen and fluid therapy.
Carbon ; Carbon Dioxide ; Central Nervous System ; Dry Ice ; Fluid Therapy ; Humans ; Inhalation ; Male ; Myocardium ; Oxygen ; Respiratory Insufficiency

We studied the effects of three inorganic carbon sources, Na2CO3, NaHCO3 and CO2, and their initial concentrations on lipid production of Chlorella vulgaris. Chlorella vulgaris could utilize Na2CO3, NaHCO3 and CO2 to produce lipids. After 10-day cultivation with each of the three inorganic carbon sources, lipid yield of Chlorella vulgaris reached its peak with the concentration increase of the inorganic carbon source, but dropped again by further increase of the concentration. The pH value of the culture medium for Chlorella vulgaris increased after the cultivation on inorganic carbon source. The optimal concentration of both Na2CO3 and NaHCO3 was 40 mmol/L, and their corresponding biomass dry weight was 0.52 g/L and 0.67 g/L with their corresponding lipid yield 0.19 g/L and 0.22 g/L. When the concentration of CO2 was 6%, Chlorella vulgaris grew the fastest and its biomass dry weight was 2.42 g/L with the highest lipid yield of 0.72 g/L. When the concentration of CO2 was too low, the supply of inorganic carbon was insufficient and lipid yield was low. A too high concentration of CO2 caused a low pH and lipid accumulation was inhibited. Na2CO3 and NaHCO3 were more favorable for Chlorella vulgaris to accumulate unsaturated fatty acids than that of CO2.
Biofuels ; Carbon ; metabolism ; Carbon Dioxide ; pharmacology ; Carbonates ; pharmacology ; Chlorella vulgaris ; growth & development ; metabolism ; Culture Media ; Culture Techniques ; methods ; Lipids ; biosynthesis ; Sodium Bicarbonate ; pharmacology

Carbon monoxide which is an odorless, colorless, non-irritating gas causes asphyxia by blocking the hemoglobin of the RBC from carrying oxygen to the tissues and from returning carbon dioxide to the lungs. The clinical symptoms of CO poisoning depend on the blood CO saturation level and in a healthy middle-aged individual a blood CO saturation greater than 50% is considered fatal. In forensic science, the investigation of the scene in cases of CO poisoning is imperative to determine the manner of death or the source of CO production, while postmortem diagnosis of CO poisoning is not difficult. The author reported four cases of CO poisoning in the unusual or atypical circumstances, which were not recognized in the scene.
Asphyxia ; Carbon Dioxide ; Carbon Monoxide Poisoning* ; Carbon Monoxide* ; Carbon* ; Diagnosis ; Forensic Sciences ; Lung ; Oxygen ; Poisoning

BACKGROUND: Cryosurgical treatment for nevus of Ota could be effective and cheap, but has not been introduced too much in detail. OBJECTIVE: This study was done to evaluate the clinical efficacy according to its determinants, and the complications of cryosurgery. METHODS: 109 patients with nevus of Ota were treated with hard chalk dry ice which contacted the skin consistently of was rolled fast. Accessible patients were evaluated by phone or direct interview. RESULTS: Satisfactions assessed by patients after cryosurgery were excellent 21%, moderate 51%, fair 17% and poor 11%, respectively. Satisfactions assessed by doctor were quite higher than those by patient. Satisfactions assessed by patients were affected by clinical determinants such as age over 40 and color of the lesion, but not by clinical type, number of sessions, and combinations with laser. Complications were in the following order : textural change, hypopigmentation, hypertrophic scar, persistent erythema, hyperpigmentation, infection and milia formation. CONCLUSION: Cryosurgery using dry ice for the treatment of nevus of Ota was quite effective but technical improvements for decreasing complications or combinations with Q switched laser and other surgical techniques might be required.
Calcium Carbonate ; Cicatrix, Hypertrophic ; Cryosurgery* ; Dry Ice ; Erythema ; Humans ; Hyperpigmentation ; Hypopigmentation ; Nevus of Ota* ; Nevus* ; Skin