OBJECTIVETo establish a method for determination of a variety of acid gas in the workplace air by Ion Chromatography. (hydrofluoric acid, hydrogen chloride or hydrochloric acid, sulfur anhydride or sulfuric acid, phosphoric acid, oxalic acid).

METHODThe sample in workplace air was collected by the porous glass plate absorption tube containing 5 ml leacheate. (Sulfuric acid fog, phosphoric acid aerosol microporous membrane after collection, eluted with 5 ml of eluent.) To separated by AS14+AG14 chromatography column, by carbonate (2.0+1.0) mmol/L (Na(2)CO(3)-NaHCO(3)) as eluent, flow rate of 1 ml/min, then analyzed by electrical conductivity detector. The retain time was used for qualitative and the peak area was used for quantitation.

RESULTSThe each ion of a variety of acid gas in the air of workplace were excellent in carbonate eluent separation. The linear range of working curve of 0∼20 mg/L. The correlation coefficient r>0.999; lower detection limit of 3.6∼115 µg/L; quantitative limit of 0.012∼0.53 mg/L; acquisition of 15L air were measured, the minimum detection concentration is 0.004 0∼0.13 mg/m(3). The recovery rate is 99.7%∼101.1%. In the sample without mutual interference ions. Samples stored at room temperature for 7 days.

CONCLUSIONThe same analysis method, the detection of various acidic gases in the air of workplace, simple operation, good separation effect, high sensitivity, high detection efficiency, easy popularization and application.

Acids, Noncarboxylic ; analysis ; Air ; analysis ; Air Pollutants, Occupational ; analysis ; Chromatography ; methods ; Gases ; Hydrochloric Acid ; Hydrofluoric Acid ; Ions ; analysis ; Limit of Detection ; Phosphoric Acids ; Sulfuric Acids ; Workplace

According to National Emergency Management Agency in Korea, numbers of death and injured in firefighters were 34 and 1,555 persons, respectively, between 2003 and 2007. Firefighting is a very dangerous and difficult work because of physical, chemical, and biological hazards. Firstly, physical hazards include burn induced by smoke and other combustion products, heat, noise, and ergonomic factors. Secondly, chemical hazards include chemical asphyxiants such as carbon monoxide, hydrogen cyanide, and hydrogen sulfide, simple asphyxiants such as carbon dioxide, chemical irritants including as hydrogen chloride, and acrolein, and so on, and other carcinogens. Finally, biological hazards include infectious agents such as hepatitis, tuberculosis, and so forth. We expect this study to help management andpromotion of firefighters' health.
Acrolein ; Biological Factors ; Burns ; Carbon Dioxide ; Carbon Monoxide ; Carcinogens ; Emergencies ; Firefighters ; Fires ; Hepatitis ; Hot Temperature ; Humans ; Hydrochloric Acid ; Hydrogen Cyanide ; Hydrogen Sulfide ; Irritants ; Korea ; Noise ; Smoke ; Tuberculosis

OBJECTIVES: This study was designed to evaluate exposure levels of various chemicals used in wafer fabrication product lines in the semiconductor industry where work-related leukemia has occurred. METHODS: The research focused on 9 representative wafer fabrication bays among a total of 25 bays in a semiconductor product line. We monitored the chemical substances categorized as human carcinogens with respect to leukemia as well as harmful chemicals used in the bays and substances with hematologic and reproductive toxicities to evaluate the overall health effect for semiconductor industry workers. With respect to monitoring, active and passive sampling techniques were introduced. Eight-hour long-term and 15-minute short-term sampling was conducted for the area as well as on personal samples. RESULTS: The results of the measurements for each substance showed that benzene, toluene, xylene, n-butyl acetate, 2-methoxyethanol, 2-heptanone, ethylene glycol, sulfuric acid, and phosphoric acid were non-detectable (ND) in all samples. Arsine was either "ND" or it existed only in trace form in the bay air. The maximum exposure concentration of fluorides was approximately 0.17% of the Korea occupational exposure limits, with hydrofluoric acid at about 0.2%, hydrochloric acid 0.06%, nitric acid 0.05%, isopropyl alcohol 0.4%, and phosphine at about 2%. The maximum exposure concentration of propylene glycol monomethyl ether acetate (PGMEA) was 0.0870 ppm, representing only 0.1% or less than the American Industrial Hygiene Association recommended standard (100 ppm). CONCLUSION: Benzene, a known human carcinogen for leukemia, and arsine, a hematologic toxin, were not detected in wafer fabrication sites in this study. Among reproductive toxic substances, n-butyl acetate was not detected, but fluorides and PGMEA existed in small amounts in the air. This investigation was focused on the air-borne chemical concentrations only in regular working conditions. Unconditional exposures during spills and/or maintenance tasks and by-product chemicals were not included. Supplementary studies might be required.
2-Propanol ; Arsenicals ; Bays ; Benzene ; Carcinogens ; Ether, Ethyl ; Ethylene Glycol ; Ethylene Glycols ; Ethylenes ; Fluorides ; Humans ; Hydrochloric Acid ; Hydrofluoric Acid ; Ketones ; Korea ; Leukemia ; Nitric Acid ; Occupational Exposure ; Occupational Health ; Phosphines ; Phosphoric Acids ; Propylene Glycol ; Propylene Glycols ; Semiconductors ; Sulfur ; Sulfuric Acids ; Toluene ; Xylenes

ABSTRACT PURPOSE: Synthetic bone products such as biphasic calcium phosphate (BCP) are mixtures of hydroxyapatite (HA) and a- tricalcium phosphate (a- TCP). In periodontal therapies and implant treatments, BCP provides to be a good bone reconstructive material since it has a similar chemical composition to biological bone apatites. The purpose of this study was to compare bone regeneration capacity of two commercially available BCP. METHODS: Calvarial defects were prepared in sixteen 9-20 months old New Zealand White male rabbits. BCP with HA and a- TCP (70:30) and BCP with Silicon-substituted hydroxyapatite (Si-HA) and a-TCP (60:40) particles were filled in each defect. Control defects were filled with only blood clots. Animals were sacrificed at 4 and 8 week postoperatively. Histomorphometric analysis was performed. RESULTS: BCP with HAand a- TCP 8 weeks group and BCP with Si-HA and a- TCP 4 and 8 weeks groups showed statistically significant in crease (P<0.05) in augmented area than control group. Newly formed bone area after 4 and 8 weeks was similar among all the groups. Residual materials were slightly more evident in BCP with HA and a- TCP 8 weeks group. CONCLUSIONS: Based on histological results, BCP with HA and a- TCP and BCP with Si-HA and a- TCP appears to demonstrate acceptable space maintaining capacity and elicit significant new bone formation when compared to natural bone healing in 4 and 8 week periods.
Animals ; Apatites ; Bone Regeneration ; Bone Substitutes ; Calcium ; Calcium Phosphates ; Durapatite ; Humans ; Hydroxyapatites ; Male ; New Zealand ; Osteogenesis ; Rabbits

This study was performed to evaluate the interfacial shear bond strength of base (direct and indirect) and repair composites with aging and surface treatment methods. Direct composite resin specimens (Charisma(R), Heraeus Kulzer, Germany) were aged for 5 min, 1 hour, 24 hours, and 1 week in 37degrees C distilled water before surface treatment, and then divided into five groups: Group 1, grinding; Group 2, grinding and application of bonding agent; Group 3, grinding, etching with 37% phosphoric acid for 30sec, and application of bonding agent; Group 4, grinding, etching with 37% phosphoric acid for 30sec, silane treatment, and application of bonding agent; Group 5, grinding, etching with 4% hydrofluoric acid for 30sec, silane treatment, and application of bonding agent. Indirect composite resin specimens (Artglass(R), Heraeus Kulzer, Germany) were aged for 1 week in 37degrees C distilled water and divided into seven groups: Group 1 - Group 5, equal to Charisma specimens; Group 6, grinding, etching with 37% phosphoric acid for 60sec, silane treatment, and application of bonding agent; Group7, grinding, etching with 4% hydrofluoric acid for 60 sec, silane treatment, and application of bonding agent. The repair material(Charisma(R)) was then added on the center of the surface (5 mm in diameter, 5 mm in height). The shear bond strength was tested and the data was analyzed using one-way ANOVA and the Student-Newman-Keuls test. The following conclusions were drawn. 1. The shear bond strength of Charisma(R) specimens aged for 1 hour was significantly higher in Group 2 and Group 5 than in Group 1 (p<0.05), and that of Charisma(R) specimens aged for 1 week was significantly higher in Group 3 and Group 5 than in Group 1 (p<0.05). No significant difference was found in the bond strength of specimens aged for 5 min and 24 hours. 2. In Group 2 of the Charisma(R) specimens, there was significant difference between the bond strength of 24 hours and that of 1 week (p<0.05). 3. In Group 4 of the Charisma(R) specimens, the shear bond strength of specimens aged for 24 hours was significantly higher than the others(p<0.05). 4. There was no significant difference between the shear bond strength of the Artglass(R) specimens. 5. Most of the Charisma(R) specimens showed cohesive fractures. Artglass(R) specimens that were etched with acid (phosphoric or hydrofluoric) for 30 sec showed more cohesive fractures.
Aged ; Aging ; Humans ; Hydrofluoric Acid ; Phosphoric Acids ; Water

OBJECTIVE: To study and compare the effects of different demineralization-inhibition methods on the shear bond strength (SBS) and fracture mode of an adhesive used to bond orthodontic brackets to demineralized enamel surfaces. METHODS: Eighty freshly extracted, human maxillary premolars were divided into 4 equal groups and demineralized over the course of 21 days. Brackets were bonded to the demineralized enamel of teeth in Group 1. In Group 2, bonding was performed following resin infiltration (ICON(R), DMG, Hamburg, Germany). Before bonding, pre-treatment with acidulated phosphate fluoride (APF) or solutions containing casein phosphopeptide-amorphous calcium phosphate with 2% neutral sodium fluoride (CPP-ACP/wF) was performed in Groups 3 and 4, respectively. The SBS values of the brackets were measured and recorded following mechanical shearing of the bracket from the tooth surface. The adhesive remnant index (ARI) scores were determined after the brackets failed. Statistical comparisons were performed using one-way ANOVA, Tukey's post-tests, and G-tests. RESULTS: Significant differences were found in some of the intergroup comparisons of the SBS values (F = 39.287, p < 0.001). No significant differences were found between the values for the APF-gel and control groups, whereas significantly higher SBS values were recorded for the resin-infiltrated and CPP-ACP/wF-treated groups. The ARI scores were also significantly different among the 4 groups (p < 0.001). CONCLUSIONS: Tooth surfaces exposed to resin infiltration and CPP-ACP/wF application showed higher debonding forces than the untreated, demineralized surfaces.
Acidulated Phosphate Fluoride ; Adhesives ; Bicuspid ; Calcium ; Calcium Phosphates ; Caseins ; Dental Enamel ; Humans ; Oral Hygiene ; Orthodontic Brackets ; Sodium Fluoride ; Tooth

Calcium pyrophosphate dihydrate (CPPD) crystal deposition disease is an inflammatory arthropathy that is defined by the deposition of CPPD crystals in articular and periarticular structures. CPPD crystal deposition disease has various clinical manifestation patterns ranging from an absence of symptoms to a severely destructive arthropathy. CPPD crystal deposition disease very rare with rheumatoid arthritis or systemic sclerosis. We report a case of CPPD crystal deposition disease combined in a patient with rheumatoid arthritis and systemic sclerosis.
Arthritis, Rheumatoid ; Calcium Pyrophosphate ; Diphosphates ; Humans ; Scleroderma, Systemic

This study was aimed to investigate the effects of bortezomib combined with 5-azacytidine on the apoptosis of K562 cells and expressiom of SHIP mRNA. The K562 cells were cultured and treated with different concentrations of bortezomib, 5-azacytidine or their combination for 24 hours. Then, the expression of SHIP mRNA was detected by RT-PCR,the cell proliferation was analyzed by using MTT assay and flow cytometry. The results showed that 5-20 nmol/L bortezomib could effectively inhibit the proliferation of K562 and this inhibitory effect gradually enhanced along with the increase of bortezomib concentration, the group of bortezomib combined with 5-azacytidine showed more inhibitory effect on K562 cells than that of bortezomib or 5-azacytidine alone.The bortezomib could promote the apoptosis of K562 cells in a dose-dependent manner,and this apoptotic effect was higher in group of bortezomib combined with 5-azacytidine than that in group of bortezomib or 5-azacytidine alone.Bortezomib could down-regulated the expression of SHIP mRNA in a dose-dependent manner,and this down-requlated effect was higher in group of bortezomib combined with 5-azacytidine than that in group of bortezomib or 5-azacytidine alone.It is concluded that bortezomib and 5-azacytidine can induce apoptosis by inhibiting the expression of SHIP mRNA in K562 cells.The combination of bortezomib with 5-azacytidine displays a synergetic effect.
Apoptosis ; drug effects ; Azacitidine ; pharmacology ; Boronic Acids ; pharmacology ; Bortezomib ; Cell Proliferation ; Humans ; Inositol Polyphosphate 5-Phosphatases ; K562 Cells ; Phosphoric Monoester Hydrolases ; genetics ; Pyrazines ; pharmacology ; RNA, Messenger ; biosynthesis

OBJECTIVE: The purpose of this study was to investigate the effect of using laser for ceramic bracket bonding of porcelain surfaces and to compare it with conventional treatment of porcelain surfaces. METHODS: Ninety feldspathic porcelain specimens were divided into 9 groups of 10, with each group having different surface treatments performed. Surface treatment groups were orthophosphoric acid, orthophosphoric acid with silane, hydrofluoric acid, hydrofluoric acid with silane, sandblasted, sandblasted with silane, laser etched, laser etched with silane, and glazed surface served as a control group. In the laser etched groups, the specimens were irradiated with 2-watt superpulse carbon dioxide (CO2) laser for 20 seconds. Ceramic brackets were bonded with light-cure composite resin and all specimens were stored in water at 37degrees C for 24 hours. Shear bond strength was determined in megapascals (MPa) by shear test at 1 mm/minute crosshead speed and the failure pattern was assessed. For statistical analysis, one-way ANOVA and tukey test were used. RESULTS: Statistical analysis showed significant differences between the groups. The HFA + S group showed the highest mean shear bond strength (13.92 +/- 1.94 MPa). This was followed by SB + S (10.16 +/- 1.27 MPa), HFA (10.09 +/- 1.07 MPa), L + S (8.25 +/- 1.24 MPa), L (7.86 +/- 0.96 MPa), OFS + S (7.22 +/- 1.09 MPa), SB (3.41 +/- 0.37 MPa), OFA (2.81 +/- 0.37 MPa), G (2,46 +/- 1.36 MPa). Bond failure patterns of HFA and silane groups, except L + S, were cohesive modes in porcelain while adhesive failure was observed in the control group and the rest of the groups. Conclusions : A 2-watt superpulse CO2 laser etching of porcelain surfaces can provide a satisfactory result for porcelain surface treatment for ceramic bracket bonding. Laser irradiation may be an alternative conditioning method for the treatment of porcelain surfaces.
Adhesives ; Carbon Dioxide ; Ceramics ; Dental Porcelain ; Hydrofluoric Acid ; Lasers, Gas ; Phosphoric Acids ; Water

The formation of bone-like apatite on porous HA/beta-TCP bioceramics in dynamic simulated body fluid (SBF) undergoing a simulated inflammation procedure (pH = 6.5) was investigated in order to study the mechanism of osteoinduction and build a new method to choose biomaterials with better bioactivity. The results showed that the surface of porous HA/beta-TCP bioceramics which underwent a simulated inflammation procedure in dynamic SBF was more smooth. The light acidity in the simulated inflammation procedure would dissolve the fine grains and the parts possessing smaller curvature radius on the surface of porous HA/beta-TCP bioceramics, which would reduce the bioceramics solubility. Followed in normal SBF (pH = 7.4), the amount of bone-like apatite formed on the porous HA/beta-TCP bioceramics was less than that of porous HA/beta-TCP bioceramics incubation in normal SBF all along. The results also showed that the amount of bone-like apatite formed on the porous HA/beta-TCP bioceramics sintered by a microwave plasma was more than that of porous HA/beta-TCP bioceramics sintered by a conventional furnace.
Apatites ; chemistry ; Biocompatible Materials ; chemistry ; Body Fluids ; chemistry ; Bone Cements ; chemistry ; Bone Substitutes ; chemistry ; Calcium Phosphates ; chemistry ; Ceramics ; Hydroxyapatites ; chemistry ; Inflammation ; Materials Testing ; methods ; Microwaves ; Osseointegration ; Porosity ; Surface Properties