Objective: To establish a inductively coupled plasma mass spectrometry method for the determination of trace cobalt and tungsten in human urine. Methods: The authors used 1% nitric acid solution as diluent in October-December 2021, the sample dilution factor and internal standard element were optimized by single factor rotation experiment, and the difference between the working curve and the standard curve was compared. Results: The method uses working curve to determine cobalt and tungsten in urine, the linear range of this method was 0.0~10.0 μg/L, the correlation coefficient was 0.999 9, the detection limits respectively were 0.005 μg/L (cobalt) and 0.09 μg/L (tungsten), the recoveries of samples respectively were 87.0%~100.2% (cobalt) and 89.4%~104.8% (tungsten), the relative standard deviations respectively were 0.4%~4.4% (cobalt) and 0.6%~3.8% (tungsten) . Conclusion: A simple and rapid method for determination of cobalt and tungsten in urine has been established. This method has the advantages of simple operation, high sensitivity, low detection limit and good stability. It is suitable for determination of cobalt and tungsten in urine of all kinds of people.
Humans ; Cobalt/analysis* ; Tungsten/analysis* ; Spectrum Analysis ; Nitric Acid ; Mass Spectrometry

BACKGROUND: Recently, carbon fibers have been utilized to develop a depth-type microelectrode array for chronic neural recording. Since the diameter of carbon fibers is smaller than the conventional electrodes made of metal wires or microfabricated silicon, the carbon fiber electrodes showed an improved capability for chronic neural recording with less tissue damages. However, the carbon fiber based microelectrodes have a limitation of short insertion depth due to a low stiffness. METHODS: We proposed a carbon fiber based microelectrode array embedded with a mechanical support structure to facilitate the penetration into the deeper brain. The support is made of biodegradable silk fibroin to reduce the reactive tissue responses. The 4-channel carbon fiber based microelectrode arrays were fabricated and accessed in terms of electrochemical impedance, recording capability for 1-month implantation in rat hippocampi. The electrodes with tungsten supports were fabricated and tested as a control group. Immunohistochemical analysis was performed to identify the reactive glial responses. RESULTS: The carbon fiber based electrode arrays with silk supports showed about 2-fold impedance increase 2 weeks after implantation while the number of active electrodes decreased simultaneously. However, after 1 month, the electrode impedance decreased back to its initial value and the percentage of active electrodes also increased above 70%. Immunohistochemical staining clearly showed that the electrodes with silk supports induced less reactive glial responses than that with tungsten supports. CONCLUSION: The proposed carbon fiber based microelectrode array is expected to be used for long-term in vivo neural recording from deep brain regions with the minimized reactive tissue response.
Animals ; Brain ; Carbon ; Electric Impedance ; Electrodes ; Fibroins ; Microelectrodes* ; Rats ; Silicon ; Silk* ; Tungsten

OBJECTIVE: We aimed to perform in-vitro evaluation to compare 1) shear bond strength (SBS), adhesive remnant index (ARI), and color change between self-etched and acid-etched primers; 2) the SBS, ARI and color change between direct and indirect bonding; and 3) the enamel roughness (ER) between 12-blade bur and aluminum oxide polisher debonding methods. METHODS: Seventy bovine incisors were distributed in seven groups: control (no bonding), direct (DTBX), and 5 indirect bonding (ITBX, IZ350, ISONDHI, ISEP, and ITBXp). Transbond XT Primer was used in the DTBX, ITBX, and ITBXp groups, flow resin Z350 in the IZ350 group, Sondhi in the ISONDHI group, and SEP primer in the ISEP group. SBS, ARI, and ER were evaluated. The adhesive remnant was removed using a low-speed tungsten bur in all groups except the ITBXp, in which an aluminum oxide polisher was used. After coffee staining, color evaluations were performed using a spectrophotometer immediately after staining and prior to bonding. RESULTS: ISONDHI and ISEP showed significantly lower SBS (p < 0.01). DTBX had a greater number of teeth with all the adhesive on the enamel (70%), compared with the indirect bonding groups (0–30%). The ER in the ITBX and ITBXp groups was found to be greater because of both clean-up techniques used. CONCLUSIONS: Direct and indirect bonding have similar results and all the primers used show satisfactory adhesion strength. Use of burs and polishers increases the ER, but polishers ensure greater integrity of the initial roughness. Resin tags do not change the color of the teeth.
Adhesives ; Aluminum Oxide ; Coffee ; Dental Enamel* ; Incisor ; Shear Strength ; Tooth ; Tungsten

No abstract available.
Kidney Failure, Chronic* ; Tungsten* ; Wolfram Syndrome*

PURPOSE: This laboratory study assessed the effect of different dentin cleaning procedures on shear bond strength of resin cements for recementing prosthesis. MATERIALS AND METHODS: 4 × 4 flat surface was prepared on the labial surface of 52 maxillary central incisors. Metal frames (4 × 4 × 1.5 mm) were cast with nickel-chromium alloy. All specimens were randomly divided into 2 groups to be cemented with either Panavia F2.0 (P) or RelyX Ultimate (U) cement. The initial shear bond strength was recorded by Universal Testing Machine at a crosshead speed of 0.5 mm/min. Debonded specimens were randomly allocated into 2 subgroups (n = 13) according to the dentin cleaning procedures for recementation. The residual cement on bonded dentin surfaces was eliminated with either pumice slurry (p) or tungsten carbide bur (c). The restorations were rebonded with the same cement and were subjected to shear test. Data failed the normality test (P < .05), thus were analyzed with Mann Whitney U-test, Wilcoxon signed rank test, and two-way ANOVA after logarithmic transformation (α = .05). RESULTS: The initial shear bond strength of group P was significantly higher than group U (P = .001). Pc and Uc groups presented higher bond strength after recementation compared to the initial bond strength. However, it was significant only in Pc group (P = .034). CONCLUSION: The specimens recemented with Panavia F2.0 provided higher bond strength than RelyX Ultimate cement. Moreover, a tungsten carbide bur was a more efficient method in removing the residual resin cement and increased the bond strength of Panavia F2.0 cement after recementation.
Alloys ; Dentin ; Incisor ; Methods* ; Prostheses and Implants ; Resin Cements* ; Tungsten

Alloys ; adverse effects ; Cobalt ; adverse effects ; Dust ; Humans ; Occupational Exposure ; adverse effects ; Tungsten ; adverse effects

Alloys ; toxicity ; Cobalt ; toxicity ; Humans ; Lung Diseases ; chemically induced ; Tungsten ; toxicity

OBJECTIVETo analyze the clinical features and investigate the clinical diagnostic methods of hard metal lung disease (HMLD), then provide reference for the diagnostic criteria of occupational HMLD.

METHODSRetrieved the open published case reports associated with HMLD from January, 2000 to June, 2014. Regarding the ages, sex, types and years of work, clinical features and laboratory results for analyzing.

RESULTSCollected 21 clinical cases of HMLD belonged to 6 internal reports and 15 oversea reports. Among them 15 male and 6 female, ages were from 22 to 58, length of service between 1 year and 43 years. Clinical presentations included cough (20 cases), dyspnea on progressive (10 cases), and pulmonary function testing showed a restrictive abnormality. The imaging features presented as bilateral areas of ground-glass attenuation, diffuse small nodules, extensive reticular opacities and traction bronchiectasis. The finding of giant cell interstitial pneumonia (GIP) was almost pathognomonic for hard metal pneumoconiosis. The main pathological findings contained a different levels of lymphocyte, acidophilic cell infiltration, hyperplasia of fibrous tissue and numerous large multinucleated histiocytes which ingested inflammatory cells were admixed with macrophages. 16 cases of the 21 reports showed GIP.

CONCLUSIONSClinical presentations include cough and dyspnea on progressive, and pulmonary function testing show a restrictive abnormality. The imaging features present as bilateral areas of ground-glass attenuation, areas of consolidation, diffuse small nodules, extensive reticular opacities and traction bronchiectasis. The prime pathological findings contain interstitial pneumonia with intra-alveolar macrophages and a large amount of multinucleated histiocytes.

Adult ; Alloys ; Cobalt ; Female ; Humans ; Lung ; physiopathology ; Lung Diseases, Interstitial ; pathology ; Macrophages, Alveolar ; Male ; Middle Aged ; Occupational Diseases ; pathology ; Pneumoconiosis ; pathology ; Tungsten ; Young Adult

PURPOSE: The aim of this study was to evaluate the effects of atmospheric plasma (APL) versus conventional surface treatments on the adhesion of self-adhesive resin cement to Ti-6Al-4V alloy. MATERIALS AND METHODS: Sixty plates of machined titanium (Ti) discs were divided into five groups (n=12): 1) Untreated (CNT); 2) Sandblasted (SAB); 3) Tribochemically treated (ROC); 4) Tungsten CarbideBur (TCB); 5) APL treated (APL). SEM analysis and surface roughness (Ra) measurements were performed. Self-adhesive resin cement was bonded to the Ti surfaces and shear bond strength (SBS) tests, Ra and failure mode examinations were carried out. Data were analyzed by one-way analysis of variance and chi-squared test. RESULTS: The lowest SBS value was obtained with CNT and was significantly different from all other groups except for APL. The ROC showed the highest SBS and Ra values of all the groups. CONCLUSION: It was concluded that the effect of APL on SBS and Ra was not sufficient and it may not be a potential for promoting adhesion to titanium.
Alloys ; Plasma Gases ; Plasma* ; Resin Cements* ; Titanium* ; Tungsten

Alloys ; Cobalt ; Humans ; Lung ; pathology ; Lung Diseases ; diagnosis ; pathology ; Tungsten