As many new drug substances contained various aromatic rings and fluorine attached to an electron rich aromatic ring or on the meta-position, a strategy towards improvement in aromatic fluorination of these compounds is highly desirable. The introduction of fluorine-18 onto aromatic rings showed in the limited condition containing electron withdrawing group (EWG) on the para- or ortho-position to get reasonable radiochemical yield so far. No-carrier added (NCA) [18F]fluoroarene syntheses by iodonium salts recently reported that has the potential to greatly increase the yield in systems or positions that normally not reactive enough to give sufficient yields in simple model reaction. This review describes the methodological approach towards effective aromatic fluorination by diaryliodonium salts and future prospects in an application of novel PET radiotracer.
Electrons ; Fluorine ; Halogenation ; Salts

OBJECTIVES: The purpose of this study was to compare the amount and rate of cumulative fluoride released over a period of 4 h from several varnishes marketed in Korea. METHODS: The following six commercial products were studied: cavity shield (CS, 22,600 ppm F), V varnish (VV, 22,600 ppm F), enamel pro varnish (EP, 22,600 ppm F), MI varnish (MI, 22600 ppm F), fluorine care (FC, 22600 ppm F), and fluor protector N (FP, 7700 ppm F). Five samples were collected from each varnish. Further, 10 mg of each varnish were applied onto an acrylic surface (diameter, 5 mm) and then immersed in 20 mL of distilled water at 37degrees C. The fluoride concentration in each sample was then analyzed after 30 min, 1, 2, 3, and 4 h, and after 4 days of exposure. RESULTS: The cumulative amount of fluoride released by FC (5.64+/-1.10 ppm) was significantly higher than that released by other products after 30 min. FC (8.55+/-1.85 ppm) and MI (8.21+/-0.81 ppm) released a significantly higher cumulative amount of fluoride after 4 h. The cumulative rate of fluoride released by FC (47.80+/-9.35%) was significantly higher than that of other products after 30 min. FC (72.44+/-15.68%) and MI (69.54+/-6.88%) showed a higher cumulative fluoride release rate after 4 h. MI sustainably released fluoride after 4 h and demonstrated a high fluoride release rate of 95.76%. CONCLUSIONS: The cumulative amount and rate of fluoride released by several varnishes were statistically significant at each time point. This data can be used by clinicians prior to selection of dental products.
Dental Enamel ; Fluorides* ; Fluorine ; Korea ; Paint* ; Water

This study was conducted by the Dept. of Preventive Medicine, Kyung-Hee University, School of Medicine as a preliminay test for the effects of Fluorine Compounds to the Plants from April through August, 1971. Fluorine was measured with Zirconium-Alizarine method and the following findings could be obtained : 1. Most high densities (25.7pptm) was found around the industrial areas and lowest (19.3pptm) around residential sections in Seoul. 2. Average density of Fluorine in the atmosphere of Seoul City was 22.3 pptm which can damage such plants as Pine, Strawberry, Peach and Grapes. 3. Fluorine contests (22.3pptm) in Seoul area atmosphere of shows about 4 times more than that of Cincinnati, Ohio, U.S.A.
Air Pollutants* ; Atmosphere ; Fluorine Compounds* ; Fluorine* ; Fragaria ; Humans ; Ohio ; Preventive Medicine ; Prunus persica ; Seoul ; Vitis

This study was conducted by the Dept. of Preventive Medicine, Kyung-Hee University, School of Medicine as a preliminay test for the effects of Fluorine Compounds to the Plants from April through August, 1971. Fluorine was measured with Zirconium-Alizarine method and the following findings could be obtained : 1. Most high densities (25.7pptm) was found around the industrial areas and lowest (19.3pptm) around residential sections in Seoul. 2. Average density of Fluorine in the atmosphere of Seoul City was 22.3 pptm which can damage such plants as Pine, Strawberry, Peach and Grapes. 3. Fluorine contests (22.3pptm) in Seoul area atmosphere of shows about 4 times more than that of Cincinnati, Ohio, U.S.A.
Air Pollutants* ; Atmosphere ; Fluorine Compounds* ; Fluorine* ; Fragaria ; Humans ; Ohio ; Preventive Medicine ; Prunus persica ; Seoul ; Vitis

China ; Fluorine ; analysis ; toxicity ; Humans ; Neoplasms ; mortality ; Water Supply ; analysis

PURPOSE: Electrophilic 18F (T1/2=110 min) radionuclide in the form of [18F]F2 gas is of great significance for labeling radiopharmaceuticals for positron emission tomography (PET). However, its production in high yield and with high specific radioactivity is still a challenge to overcome several problems on targetry. The aim of the present study was to develop a method suitable for the routine production of [18F]F2 for the electrophilic substitution reaction. MATERIALS AND METHODS: The target was designed water-cooled aluminum target chamber system with a conical bore shape. Production of the elemental fluorine was carried out via the 18O(p,n)18F reaction using a two-step irradiation protocol. In the first irradiation, the target filled with highly enriched 18O2 was irradiated with protons for 18F production, which were adsorbed on the inner surface of target body. In the second irradiation, the mixed gas (1% [19F]F2/Ar) was loaded into the target chamber, following a short irradiation of proton for isotopic exchange between the carrier-fluorine and the radiofluorine absorbed in the target chamber. Optimization of production was performed as the function of irradiation time, the beam current and 18O2 loading pressure. RESULTS: Production runs was performed under the following optimum conditions: The 1st irradiation for the nuclear reaction (15.0 bar of 97 % enriched 18O2, 13.2 MeV protons, 30 micro A, 60-90 min irradiation), the recovery of enriched oxygen via cryogenic pumping; The 2nd irradiation for the recovery of absorbed radiofluorine (12.0 bar of 1% [19F]fluorine/argon gas, 13.2 MeV protons, 30 micro A, 20-30 min irradiation), the recovery of [18F]fluorine for synthesis. The yield of [18F]fluorine at EOB (end of bombardment) was achieved around 34+/-6.0 GBq (n>10). CONCLUSION: The production of 18F electrophilic agent via 18O(p,n)18F reaction was much under investigation. Especially, an aluminum gas target was very advantageous for routine production of [18F]fluorine. These results suggest the possibility to use [18F]F2 gas as a electrophilic substitution agent.
Aluminum ; Fluorine ; Oxygen ; Positron-Emission Tomography ; Protons ; Radioactivity ; Radiopharmaceuticals

OBJECTIVES: This study aimed to confirm the efficacy of the urinary fluoride concentration/creatinine ratio for monitoring fluorine intake in fluoridated and non-fluoridated communities. METHODS: The correlations among the fluoride concentration in drinking water and that in the urine and fingernails of 52 preschool children (age, 60-72 months) from fluoridated and non-fluoridated communities were analyzed. RESULTS: The urinary fluoride concentration/creatinine ratio had a relatively high correlation with the fluoride concentration in drinking water (Pearson's correlation coefficient, 0.606; P<0.05). Further, this ratio was significantly positively correlated with the urinary fluoride concentration (Pearson's correlation coefficient, 0.374; P<0.01). However, there was no significant correlation between this ratio and the fluoride concentration in fingernails (Pearson's correlation coefficient, 0.145; P>0.05). CONCLUSIONS: The findings of this study suggest that the urinary fluoride concentration/creatinine ratio in children can be utilized as an index for monitoring excess fluoride intake in fluoridated communities.
Child ; Child, Preschool ; Drinking ; Drinking Water ; Fluoridation ; Fluorides ; Fluorine ; Humans ; Nails

Calcitonin ; blood ; Fluorine ; adverse effects ; Humans ; Occupational Exposure ; adverse effects ; Osteocalcin ; blood

The chemical shift of fluoxetine hydrochloride appears at delta 14.15 in 19F NMR analysis. The delta moved upfield slightly from 14.158 to 14.145 when the concentration of solution became diluted from 2.00 to 0.05 mmol x L(-1). Spiking test was suggested to confirm the existence of the compound for qualitative analysis. 19F NMR detection sensitivity test illustrated that a concentration of 17 mg in 1 L water could be detected while the sample was scanned 500 times with optimum parameters. In quantitative analysis, standard curve of concentration versus fluorine signal intensity was proposed to determine the amount of fluoxetine. Long capillary tube containing trifluoroacetic acid was used as internal standard for the integration measurements and straight line was obtained with good fitting. Direct additions of trifluoroethanol to fluoxetine solutions gave a poorer standard curve.
Fluorine ; chemistry ; Fluoxetine ; analysis ; chemistry ; Magnetic Resonance Spectroscopy ; Molecular Structure ; Trifluoroacetic Acid ; analysis

PURPOSE: To assess the utility of 2-[18F] fluoro-2-deoxy-D-glucose (FDG) PET in differentiating malignant and benign diffuse pleural disease, and to compare it with CT. MATERIALS AND METHODS: Both FDG PET and CT scans were performed in 20 consecutive patients with diffuse pleural disease (13 malignant and seven benign cases). In FDG PET, peak standardized uptake value (SUV) as well as visual assessment of abnormally increased uptake in the pleura was evaluated. The results were compared with CT findings. RESULTS: With only visual assessment of PET images, sensitivity, specificity, and accuracy for malignancy were 92%, 43%, and 75%, respectively. With peak SUV of 4.8 or more, the corresponding figures were 100%, 57%, and 85%, respectively, and on CT interpretation, were100%, 57%, and 85%, respectively. Tuberculous empyema simulated malignant pleural disease both on FDG PET (3/6 patients with peak SUV more than 4.8) and CT (3/6 patients). CONCLUSION: For the differentiation of malignant and benign diffuse pleural disease, FDG PET and CT are equally accurate. Combined visual and quantitative assessments of PET images enhance discriminatory ability. Tuberculous empyema simulates malignant pleural disease both on FDG PET and CT.
Diagnosis, Differential* ; Empyema, Tuberculous ; Fluorine ; Humans ; Pleura ; Pleural Diseases* ; Sensitivity and Specificity ; Tomography, X-Ray Computed