[Comparison of color change of silorane and methacrylate-based composites due to bleaching]

Bleaching treatments may alter the color stability of composite restorations. Silorane-based composites have shown similar or superior physical and mechanical properties compared to other types of composites. Furthermore, studies have shown variable and sometimes contradictory results regarding the effect of bleaching agents on the color stability of composite restorations. This study aimed to assess the effect of two Iranian bleaching agents on color stability of a Silorane-based [P90] composite compared with two methacrylate-based composites [nanofiller[Z350] and microhybrid. [Z250]. In this in vitro study, a total of 18 disc-shaped specimens [10 x 2 mm] of Z250, Z350 and P90 composites [A3 shade] were fabricated and randomly divided into 3 groups [n=6] and subjected to bleaching treatment with 16 % carbamide peroxide, 35% carbamide peroxide and distilled water as the control group. Color parameters were measured using CIE-L*a*b* system and a spectrophotometer before and after bleaching. The factors were statistically analyzed by means of two-sided ANOVA [repeated measures ANOVA] and Tukey's multiple comparisons tests.The mean +/- standard deviation of total color change [delta E] in control, 16% carbamide peroxide and 35% carbamide peroxide groups was 3.48 +/- 1.43,4.55 +/- 1.7 and 4.17 +/- 1.9, for Z250, 4.33 +/- 2.41, 4.94 +/- 2.23 and 4.25 +/- 1.65, for Z350 and 4.97 +/- 2.47, 5.28 +/- 1.67 and 3.4U2.26 for P90, respectively. delta E was clinically perceptible after bleaching treatments of all composite materials [delta E>3.3]

Targetry for cyclotron production of no carrier-added cadmium- 109 from natAg[p, n] 109 Cd reaction

Solid targets that consist of powder and electrodeposited targets are used commonly to produce radionuclides by accelerators. Since silver is easily electrodeposited in cyanide baths and has a very excellent thermal conductivity, the electrodeposited target is preferable to produce [109] Cd. To avoid cracking of peeling of the target during bombardment, it should have a level surface and a good adhesion to substrate. Hence, suitable targetry has extraordinary importance for the interested radionuclide production. Excitation function of cadmium-109 via [nat] Ag [p,n][109] Cd reaction was investigated by using ALICE-91 code. The required thickness of the silver deposit was calculated by SRIM code. Theoretical yield was calculated by means of Simpson numerical integral method. Silver was electrodeposited on copper backing by the cyanide bath. The prepared targets were examined with morphology and thermal shock tests. The most favorable beam energy was determined as 15 MeV. The desired thickness was determined to be up to 48 micro m; the theoretical calculated yield was 2.69 micro Ci/ micro A.h. Scanning electron microscope [SEM] potomicrographs and thermal shock tests represented excellent quality of the electrodeposited target. The present study suggested a good potentiality of cadmium-109 production by induced proton on electrodeposited silver targets

[Experimental production and initial imaging of [18 F]-14-Fluoro-6-thia-hepatadecanoic acid [[18F]-FTHA] for myocardial performance]

[18F]-6-thia-14-fluoro-heptadecanoic acid 3b, a free fatty acid, has been used in myocardial PET imaging. In order to establish an automated synthesis module for routine production in the country, a study performed for optimization of the production conditions as well as making modifications. [18F] Benzyl-14-Fluoro-6-thia-heptadecanoate 2b was prepared in no-carrier-added [n.c.a] form from C in Benzyl-14-tosyloxy-6-thia-heptadecanoate 1 in one step at 90 Kryptofix2.2.2/[18F] and acetonitrile as the solvent followed by Silica column chromatography. The radiolabeled ester 2 was then hydrolyzed to yield [18F]-6-thia-14-fluoro-heptadecanoic 3b. The final solution was concentrated using C18 SPE system and administered to normal rats for biodistribution as well as co-incidence imaging studies. The synthesis took 15 min with overall radiochemical yield of 15-25% [EOS] and chemical-radiochemical purity more than 94%. Automation was performed using a two-pot synthesis. The best imaging time was shown to be 140-180 minutes post injection. Using this procedure a fast, reliable, automated synthesis for the cordial PET tracer, i.e. [18F]-FTHA can be obtained without HPLC purification step

[Production, formulation, quality control and primary biological studies of [18F]KF for skeletal PET scanning]

[[18]F]KF, considered as a reference standard for positron emission tomography of the skeletal system, was produced by the bombardment of enriched water [[18O]H2O>95%] with high energy protons in NRCAM cyclotron. After the extraction of fluoride from enriched water as KF, and passing it through microbial filter and fine adjustment of acidity and osmolality, it was converted into an injectable form. Pre-clinical investigations and biological controls were performed to determine radioisotope distribution in laboratory rats, thus suitable information was gathered for imaging in humans. This radiopharmaceutical was proved to be quite safe and of high quality as a result of testing in laboratory rats

Study of lactobacillus as probiotic bacteria

Because of inhibitory effect, selected probiotic lactobacilli may be used as biological preservative, so, the aim of this study was to present some data on lactobacillus as probiotic bacteria. Lactic acid bacteria were isolated from sausage. Each isolate of lactobacillus species was identified by biochemical tests and comparing their sugar fermentation pattern. Antibacterial activities were done by an agar spot, well diffusion and blank disk method. Enzyme sensitivity of supernatant fluid and concentrated cell free culture after treatment with alpha-amylase, lysozyme and trypsin was determined. The isolated bacteria were Lacto. plantarum, Lacto delbruekii, Lacto. acidophilus, Lacto. brevis. The isolated bacteria had strong activity against indicator strains. The antibacterial activity was stable at 100°C for 10 min and at 56°C for 30 min, but activity was lost after autoclaving. The maximum production of plantaricin was obtained at 25 - 30°C at pH 6.5. Because, lactobacilli that used to process sausage fermentation are producing antimicrobial activity with heat stability bacteriocin, so, these bacteria may be considered to be a healthy probiotic diet. Lactobacilli originally isolated from meat products are the best condidates as probiotic bacteria to improve the microbiological safety of these foods

Production of [18 F] fluoride with a high-current two layer spherical gold target

Fluoride-18 is the most widely used radioisotope for Positron Emission Tomography [PET]. [18F] 2-flouro- 2-deoxy D-glucose [FDG] has become a standard tool in the area of clinical research. The oxygen-18 enriched water is the most widely used target for the production of fluoride-18. The use of the nuclear reaction 18O [p,n]18F has been found as the most effective method for the production of [18F] fluoride. Materials and methods: Gold is a chemically resistant metal, which has been found wide application in the chemical industry where it is often used in corrosive environments at high temperature.It is also one of the highest thermal conductivity of metals. A two layer-spherical gold chamber design was chosen to obtain a maximum pressure stability under high beam currents. The target body is consisted of two chambers, internal chamber for internal cooling and external chamber for enriched water target. The target is irradiated with 28 MeV protons energy. The incident energy on the target chamber is 18 MeV. This target is operated without external over-pressure and has been tested for beam currents up to 60 micro A. The measured target yield is 2655 MBq/micro Ah. There is found that saturation yield is 8.3 GBq/micro A and shows 80% of theoretical yield. It was observed that gold is a good material for the construction of the target chamber, and also the spherical chambers are the best construction to bearing high pressure under high-current beam condition up to 60 micro A