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

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

Administration, Inhalation ; Animals ; Disease Models, Animal ; Female ; Fluorine ; blood ; Fluorocarbons ; adverse effects ; pharmacokinetics ; Male ; Rabbits ; Rats

OBJECTIVETo analyze the mechanism of fluorine by systemic analysis of fluorination-demineralization-remineralization experiments.

METHODSThe enamel specimens were randomly assigned to untreated group (group A), non-fluoride group (group B), low-fluoride group (group C) and high-fluoride group (group D). The in vitro model of fluoride enamel was established in group C and D. Based on that, the establishment of demineralization model and remineralization experiment by pH-cycling in group B, C and D were followed. All enamel specimens were observed by stereomicroscope and scanning electron microscope and compared in surface microhardness value.

RESULTSThere was distinct difference in micro-morphologic appearance on fluoride enamel surface. Artificial caries of fluoride enamel showed a relatively complete surface, the surface microhardness after demineralization and remineralization in fluoride group was higher than non-fluoride group (P < 0.05).

CONCLUSIONThe fluorinated enamel can enhance cariostatic potential and remineralization capacity of dental enamel.

Dental Caries ; Dental Enamel ; Fluorides ; Fluorine ; Humans ; Phosphates ; Tooth Demineralization ; Tooth Remineralization

BACKGROUNDThe fluorosis derived from coal burning is a very serious problem in China. By using fluorine-fixing technology during coal burning we are able to reduce the release of fluorides in coal at the source in order to reduce pollution to the surrounding environment by coal burning pollutants as well as decrease the intake and accumulating amounts of fluorine in the human body. The aim of this study was to conduct a pilot experiment on calcium-based fluorine-fixing material efficiency during coal burning to demonstrate and promote the technology based on laboratory research.

METHODSA proper amount of calcium-based fluorine sorbent was added into high-fluorine coal to form briquettes so that the fluorine in high-fluorine coal can be fixed in coal slag and its release into atmosphere reduced. We determined figures on various components in briquettes and fluorine in coal slag as well as the concentrations of indoor air pollutants, including fluoride, sulfur dioxide and respirable particulate matter (RPM), and evaluated the fluorine-fixing efficiency of calcium-based fluorine sorbents and the levels of indoor air pollutants.

RESULTSPilot experiments on fluorine-fixing efficiency during coal burning as well as its demonstration and promotion were carried out separately in Guiding and Longli Counties of Guizhou Province, two areas with coal burning fluorosis problems. If the calcium-based fluorine sorbent mixed coal was made into honeycomb briquettes the average fluorine-fixing ratio in the pilot experiment was 71.8%. If the burning calcium-based fluorine-fixing bitumite was made into a coalball, the average of fluorine-fixing ratio was 77.3%. The concentration of fluoride, sulfur dioxide and PM10 of indoor air were decreased significantly. There was a 10% increase in the cost of briquettes due to the addition of calcium-based fluorine sorbent.

CONCLUSIONSThe preparation process of calcium-based fluorine-fixing briquette is simple yet highly flammable and it is applicable to regions with abundant bitumite coal. As a small scale application, villagers may make fluorine-fixing coalballs or briquettes by themselves, achieving the optimum fluorine-fixing efficiency and reducing indoor air pollutants providing environmental and social benefits.

Air Pollution ; prevention & control ; Calcium ; chemistry ; China ; Coal ; analysis ; Fluorine ; chemistry ; Humans