PURPOSE: For the research of Boron Neutron Capture Therapy (BNCT), fast neutrons generated from the MC-50 cyclotron with maximum energy of 34.4 MeV in Korea Cancer Center Hospital were moderated by 70 cm paraffin and then the dose characteristics were investigated. Using these results, we hope to establish the protocol about dose measurement of epi-thermal neutron, to make a basis of dose characteristic of epi-thermal neutron emitted from nuclear reactor, and to find feasibility about accelerator-based BNCT. METHOD AND MATERIALS: For measuring the absorbed dose and dose distribution of fast neutron beams, we used Unidos 10005 (PTW, Germany) electrometer and IC-17 (Far West, USA), IC-18, EIC-1 ion chambers manufactured by A-150 plastic and used IC-17M ion chamber manufactured by magnesium for gamma dose. There chambers were flushed with tissue equivalent gas and argon gas and then the flow rate was 5 cc per minute. Using Monte Carlo N-Particle (MCNP) code, transport program in mixed field with neutron, photon, electron, two dimensional dose and energy fluence distribution was calculated and there results were compared with measured results. RESULTS: The absorbed dose of fast neutron beams was 6.47x10-3 cGy per 1 MU at the 4 cm depth of the water phantom, which is assumed to be effective depth for BNCT. The magnitude of gamma contamination intermingled with fast neutron beams was 65.2+/-0.9% at the same depth. In the dose distribution according to the depth of water, the neutron dose decreased linearly and the gamma dose decreased exponentially as the depth was deepened. The factor expressed energy level, D20/D10, of the total dose was 0.718. CONCLUSION: Through the direct measurement using the two ion chambers, which is made different wall materials, and computer calculation of isodose distribution using MCNP simulation method, we have found the dose characteristics of low fluence fast neutron beams. If the power supply and the target material, which generate high voltage and current, will be developed and gamma contamination was reduced by lead or bismuth, we think, it may be possible to accelerator-based BNCT.
Argon ; Bismuth ; Boron Neutron Capture Therapy* ; Boron* ; Cyclotrons ; Electric Power Supplies ; Fast Neutrons* ; Hope ; Korea ; Magnesium ; Neutrons ; Nuclear Reactors ; Paraffin ; Plastics ; Water

PURPOSE: The purpose of this study was to evaluate the effect of surface treatment on the shear bond strength of zirconia ceramic to 3 resin cements. MATERIALS AND METHODS: A total of 143 disk-shaped Zirconia blocks (HASS Co., Gangneung, Korea) were randomly divided into three treatment groups: (1) only 50 microm Al2O3 sandblasting, (2) 50 microm Al2O3 sandblast and zircona liner, (3) 50 microm Al2O3 sandblasting and Rocatec (3M ESPE, Seefeld, Germany). Bistite II (Tokuyama Dental Co., Japan), Panavia F (Kuraray Medical, Japan), and Superbond C&B (Sun Medical, Japan) were used to cement onto the zirconia. After 24h of storage in distilled water, shear bond strength was evaluated. High value group was re-tested after thermocycling at 5,000 cycles(5-55degreesC). Shear bond strength data were analyzed with one-way ANOVA, two-way ANOVA test and Post Hoc Test (alpha=.05). Shear bond strength data before and after thermocycling were analyzed with Independent sample T test (alpha=.05). RESULTS: Super-bond C&B treated with Rocatec showed the most high shear bond strength. Super-bond C&B groups resulted in significantly higher than other cement groups (P<.05). Rocatec groups resulted in significantly higher than other surface treatment groups (P<.05). Shear bond strength has increased in Panavia F treated with Zirconia liner (P<.05). After thermocycling, shear bond strength was increased in Super-bond C&B treated with Rocatec but decreased in other groups (P<.05). CONCLUSION: Super-bond C&B cement resulted the highest shear bond strength and Rocatec system enhanced the shear bond strength. After thermocycling, shear bond strength has decreased in most resin cements except Super-bond C&B treated with Rocatec.
Boron Compounds ; Ceramics ; Dental Cements ; Methacrylates ; Methylmethacrylates ; Resin Cements ; Resins, Synthetic ; Water ; Zirconium

PURPOSE: The aim of this study was to determine whether the push-out bond strengths between the radicular dentin and fiber reinforced-composite (FRC) posts with various resin cements decreased or not, according to the coronal, middle or apical level of the root. MATERIALS AND METHODS: FRC posts were cemented with one of five resin cement groups (RelyX Unicem: Uni, Contax with activator & LuxaCore-Dual: LuA, Contax & LuxaCore-Dual: Lu, Panavia F 2.0: PA, Super-Bond C&B: SB) into extracted human mandibular premolars. The roots were sliced into discs at the coronal, middle and apical levels. Push-out bond strength tests were performed with a universal testing machine at a crosshead speed of 0.5 mm/min, and the failure aspect was analyzed. RESULTS: There were no significant differences (P>.05) in the bond strengths of the different resin cements at the coronal level, but there were significant differences in the bond strengths at the middle and apical levels (P<.05). Only the Uni and LuA cements did not show any significant decrease in their bond strengths at all the root levels (P>.05); all other groups had a significant decrease in bond strength at the middle or apical level (P<.05). The failure aspect was dominantly cohesive at the coronal level of all resin cements (P<.05), whereas it was dominantly adhesive at the apical level. CONCLUSION: All resin cement groups showed decreases in bond strengths at the middle or apical level except LuA and Uni.
Adhesives ; Bicuspid ; Boron Compounds ; Collodion ; Composite Resins ; Dental Cements ; Dentin ; Humans ; Methacrylates ; Methylmethacrylates ; Resin Cements

Animals ; Boron ; analysis ; urine ; Ion-Selective Electrodes ; Minerals ; chemistry ; Urine ; chemistry

OBJECTIVETo study the effects of two primers on the bond strengths between casting pure titanium and resin cements.

METHODSTwo sizes of specimen were fabricated by casting, which diameter were 4 mm and 5 mm respectively, and then were cut into 3 mm thick titanium discs. The titanium surfaces were polished with silicon carbide sand papers under running water and then treated by sandblasting. The two size of titanium discs were ultrasonic cleaned and treated with Alloy Primer, V-Primer or without primer, and then bonded in pairs with the resin-based cements Super-Bond C&B, Panavia F and Rely X Unicem. The specimens were then stored in distilled water (37 degrees C) for 24 h. Bond strengths were determined before and after 5 000 thermocycling. The titanium surface morphous and failure mode of the teat specimen were observed.

RESULTSThe shear bond strengths of titanium treated by Alloy Primer to Super-Bond C&B were (31.23 +/- 4.86), (34.08 +/- 3.36) MPa before and after 5 000 thermocycling, which higher than that of other combinations of primers and resin cements.

CONCLUSIONBond strengths were influenced by primers, resin cements, and their combinations. The highest bond strengths were the combinations of Alloy Primer and Super-Bond C&B.

Boron Compounds ; Dental Bonding ; Dental Enamel ; Fluorescence ; Methacrylates ; Methylmethacrylates ; Resin Cements ; Thiones ; Titanium ; Triazines

OBJECTIVETo explore the effects of micro-elements fertilizers on the quality and yields of Artemisia annua.

METHODField experiments were conducted according to the method of random blocks design. After the harvest the yield was calculated and the content of artemisinin was determined.

RESULTBy applying 0.1%-0.5% Mn and 0.1%-0.5% Zn the dried leaf output and artemisinin content were increased.

CONCLUSIONThe suitable ranges of Mn and Zn can increased the yield and artemisinin content of A. annua.

Artemisia annua ; drug effects ; metabolism ; Artemisinins ; metabolism ; Boron ; pharmacology ; Manganese ; pharmacology ; Zinc ; pharmacology

OBJECTIVETo investigate the effects of overdose fluoride, boron and two factors on the expression of enamelin in rat incisor.

METHODS32 Wistar rats were randomly divided into 4 groups. Group I: The distilled water was given. Group II: 220 mg/L NaF were given. Group III: 382 mg/L Na2B4O2.10H2O were given. Group IV: 220 mg/L NaF and 382 mg/L Na2B4O2.10H2O were given. The rats were sacrificed in the eighth week. HE staining was used to observe the morphology of ameloblasts. Immunohistochemical staining was used for study the expression of enamelin in rat incisors.

RESULTSThe results showed that the expression of enamelin was reduced in the group II (P<0.01). Compared with group I, the expression of enamelin in group IV had no significant difference. The expression of enamelin in group IV and group II had significant difference (P<0.01).

CONCLUSIONThe overdose fluoride can inhibit the expression of enamelin. The effection was weaken when boron added. Boron reduced the toxicity of fluoride on teeth.

Ameloblasts ; Animals ; Boron ; Dental Enamel Proteins ; Fluorides ; Incisor ; Phosphates ; Rats ; Rats, Wistar ; Tooth

The purpose of this research was to investigate the effect of the boron supplementation on lipid profiles and antioxidant capacities in ovariectomized (OVX) rats. Rats were divided into 3 groups and fed diet with intake levels of boron (0.5 ppm, 50 ppm, 100 ppm) for 4 weeks. The half of rats in each group was ovariectomized and the others were sham-operated. And rats were fed same diets for 8 weeks after operation. Feed intake and weight gain were significantly increased by increasing boron intake and higher in OVX group than those in sham-operated. FER was significantly higher in OVX group than that of sham-operated. There were no significant differences in serum lipid profiles among the groups. The contents of hepatic total lipid were significantly higher in OVX group than those of sham-operated and the lowest in high-boron group. Hepatic GST activity was significantly decreased by ovariectomy and the lowest in very high-boron group. Hepatic catalase activity was the lowest in high-boron group of OVX. Hepatic TBARS level of high-boron group was the lowest in sham-operated groups. Hepatic TBARS level induced by AAPH was significantly decreased by increasement of boron supplementation. Taken together, this results suggest that the boron supplementation have the potential role for improving lipid profiles and antioxidant capacities in OVX rats.
Animals ; Boron* ; Catalase ; Diet ; Female ; Ovariectomy ; Rats* ; Thiobarbituric Acid Reactive Substances ; Weight Gain

Inositol 1,4,5-trisphosphate receptors (InsP3Rs) modulate Ca2+ release from intracellular Ca2+ store and are extensively expressed in the membrane of endoplasmic/sarcoplasmic reticulum and Golgi. Although caffeine and 2-aminoethoxydiphenyl borate (2-APB) have been widely used to block InsP3Rs, the use of these is limited due to their multiple actions. In the present study, we examined and compared the ability of caffeine and 2-APB as a blocker of Ca2+ release from intracellular Ca2+ stores and Ca2+ entry through store-operated Ca2+ (SOC) channel in the mouse pancreatic acinar cell. Caffeine did not block the Ca2+ entry, but significantly inhibited carbamylcholine (CCh)-induced Ca2+ release. In contrast, 2-APB did not block CCh-induced Ca2+ release, but remarkably blocked SOC-mediated Ca2+ entry at lower concentrations. In permeabilized acinar cell, caffeine had an inhibitory effect on InsP3-induced Ca2+ release, but 2-APB at lower concentration, which effectively blocked Ca2+ entry, had no inhibitory action. At higher concentrations, 2-APB has multiple paradoxical effects including inhibition of InsP3-induced Ca2+ release and direct stimulation of Ca2+ release. Based on the results, we concluded that caffeine is useful as an inhibitor of InsP3R, and 2-APB at lower concentration is considered a blocker of Ca2+ entry through SOC channels in the pancreatic acinar cell.
Acinar Cells ; Animals ; Boron Compounds ; Caffeine ; Calcium ; Carbachol ; Inositol 1,4,5-Trisphosphate Receptors ; Membranes ; Mice ; Reticulum

China is rich in antimony, boron, and vanadium mineral resources, which have been detected in environmental water bodies and drinking water. During the revision process of the "Standards for Drinking Water Quality (GB5749-2006)", research and evaluation are focused on three indicators: antimony, boron and vanadium. Vanadium is added and the limit value of boron is adjusted. This study reviews and discusses the technical contents related to the revision of the antimony, boron and vanadium, including the environmental presence levels, exposure status, health effects, and the revision of the standard limits of these three indicators. Suggestions are also made for the implementation of this standard.
Humans ; Antimony ; Boron/analysis* ; China ; Drinking Water ; Vanadium ; Water Pollutants, Chemical/analysis*