مهدی اخلاقی

Erwinia amylovora, the cause of apple and pear fire blight disease, is one of the main factors limiting the production of these fruits in the world. Since only a limited number of copper compounds have a protective effect in controlling this disease, increasing attention has been paid to investigating the effect of plant essential oils on this pathogen.

The effect of different concentrations of carvacrol (the active ingredient of thyme, oregano, etc.) and trans-anethole (the active ingredient of fennel essential oil) on the growth of E. amylovora colony, was investigated in laboratory conditions, and their minimum inhibitory concentration (MIC), and minimum bactericidal concentration (MBC) were determined. The inhibitory effect of MIC of these substances alone and the mixture of one-half of their MIC and MBC concentrations was investigated by disc method on nutrient agar medium on the growth of E. amylovora colony. The effect of the three best mixing ratios of these materials on the fruit tissue of the pear Spadona variety was evaluated on the severity of fire blight disease.

Carvacrol and trans-anethole both had antibacterial effects against E. amylovora, but the effect of carvacrol was greater than the other. Mixing carvacrol with trans-anethole increased its effectiveness. Among the three mixing ratios, 47 µg/ml of carvacrol + 141 µg/ml of trans-anethole caused the greatest reduction in disease severity in pear fruit tissue.

The use of a mixture of carvacrol and trans-anethole can be considered for the management of fire blight disease.

Thyroid cancer is the most common endocrine malignancy in the world; however, these patients usually experience a high survival rate if they receive appropriate and timely treatment. Meanwhile, patients classified as having differentiated thyroid cancer with high thyroglobulin and negative iodine scan [Differentiated thyroid cancer with thyroglobulin elevation and negative iodine scintigraphy (TENIS)] are always considered a diagnostic-therapeutic challenge.

We conducted a comprehensive literature search of published papers in the PubMed/MEDLINE database regarding nuclear imaging in differentiated thyroid cancer with thyroglobulin elevation and negative iodine scintigraphy. We included all human studies in this field.

In this review, we examined four major groups of imaging studies aimed at identifying GLUT, SSTR, PSMA and FAP receptors in patients with TENIS. The diagnostic rate of 2-[18F]FDG PET/CT in these patients has been reported as 63-81% based on various studies. Also, [68Ga]Ga-DOTATATE PET/CT, [68Ga]Ga-PSMA PET/CT and [68Ga]Ga-FAPI PET/CT scans have shown good results in these patients.

[68Ga]Ga-FAPI PET/CT imaging has the highest diagnostic rate among these patients. Given the theranostic capability of FAPI and the numerous complications and limited inclusion criteria for treatment with tyrosine kinase inhibitors, it has been the next step in the treatment of patients with TENIS. Therefore, more extensive studies in this field are warranted.

Wilt disease caused by the pathogenic fungus Verticillium dahliae is one of the dangerous factors threatening the cultivation of pistachio trees in the country, which has spread in different parts of the country in the last two decades, including Semnan province. Lack of suitable fungicides to control V. dahliae and continuous use of several common fungicides in the country has contributed to the spread of the fungus. Therefore, in the current situation, we need to use new compounds with high efficiency to control this pathogenic fungus. Plant essential oils and their monoterpene compounds are considered as one of the important options due to the comparative advantage of the production of medicinal plants in the country.

In this study, V. dahliae native isolates obtained from gardens of Semnan province were used. Isolation and identification process was performed using conventional methods and isolates were identified using general ITS primer. Then, the essential oils of thyme (Zataria multiflora) and Peppermint (Mentha piperita) were used to evaluate the antifungal effect. After preparing the herbal plants, the essential oil extraction process was performed using Clevenger method. The antifungal effect was investigated by mixing with culture medium at concentrations of 20, 40, 60, 80 and 100 μg/ml. Also, the minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MBC) were determined for the two essential oils. Then, using thymol and carvacrol monoterpenes, antifungal effects were tested by mixing with culture medium at three concentrations of 15, 150 and 1500 μg/ml against V. dahliae.

Isolation and identification tests confirmed the presence of V. dahliae in the sampled areas. The use of ITS primer confirmed the fungal species V. dahliae. The results of antifungal effect showed that both essential oils were effective in preventing the growth of fungi, but Zataria multiflora essential oil was evaluated as stronger, so that in the third week, growth was observed only at a concentration of 20 μg/ml, but in the case of peppermint essential oil, fungus growth was observed in all concentrations. The results showed that the minimum inhibitory (MIC) and minimum fungicidal (MFC( concentrations were 20 and 30 μg/ml for thyme and 100 and 150 μg/ml for peppermint essential oils, respectively. In addition, the results showed that thymol was more potent than carvacrol in preventing the growth of V. dahliae.

The results of this study showed that plant essential oils and monoterpene compounds of essential oils had a very high ability to control Verticillium fungus, so that compared to common fungicides in the country, their inhibitory concentration was 10 to 15 times lower

Pseudomonas tolaasii is one of the most important pathogenic bacteria of the edible fungus (Agaricus bisporus) in Iran and the world. In this study, comparing the severity of pathogenicity of the isolates showed that the highest pathogenicity was related to isolate Pt 4. Antibacterial effect of 10 plant essential oils against isolate Pt 4 was measured by disk diffusion method and based on the diameter of the inhibitory halo, basil and thyme essential oils had the highest antibacterial effect, respectively. The results of chemical analysis of gas chromatography showed that methyl chavicol with 67.05% was the highest monoterpene compound of basil essential oil, which together with two well-known compounds of thyme including carvacrol and thymol showed a controlling effect against P. tolaasii. The results showed that the best effect in controlling the disease on the fungal cap at minimum inhibitory concentration (MIC) was for thymol, carvacrol and methyl chavicol, respectively, but at some concentrations higher than MIC, thymol and carvacrol caused symptoms of cap blackening. Methyl chavicol had no adverse effect against Agaricus bisporus in all concentrations used, despite having less effect on reducing pathogenicity. Therefore, the use of methyl chavicol combination can be a good option to prevent bacterial brown blotch disease in mushroom cultivation halls.

Fire blight, caused by Erwinia amylovora, is one of the important bacterial diseases of pome fruit trees. It causes the blight of different organs of the tree (blossoms, shoots, leaves, fruits, and limbs) and exudates' production. The main symptoms of fire blight infection are the burnt-like appearance of infected tissues, bacterial ooze released from the infected tissues, shepherd’s crook, wilting, and water-soaked appearance. Recently, it has been included in the top 10 plant pathogenic bacteria. This study aimed to collect, identify and characterize E. amylovora isolates from provinces of Semnan in Iran and determine their pathogenicity factor and the current situation of fire blight disease in this province.

In the present study, 68 strains isolated from pear, quince, and apple hosts were identified in Semnan Provinces. Phenotypic, nutritional, and biochemical tests were performed on strains. The molecular identification of isolates was conducted using specific primers A and B of the plasmid pEA29. A pathogenicity test of the bacterial isolates on the immature pear fruit of the Spadona pear cultivar was performed, and the most pathogenic bacterium isolate was selected for further evaluation. Pathogenicity test was carried out on immature fruits and blooms of eight pear cultivars. Pathogenicity characteristics such as amylovoran, biofilm, and siderophore were studied in most virulence isolates.

The isolates were gram and oxidase negative, catalase-positive, and anaerobic. The isolates were able to produce a hypersensitive response in tobacco and levan production, but none of them could produce fluorescent pigment on King B medium and growth at 39 °C. The results suggested that of 68 strains collected, 52 isolates belong to Erwinia amylovora bacteria. The virulent isolate (D 43) was collected from Dibaj city. All 52 isolates under study proliferated 1000 base pairs. These tests, along with sequencing of PCR products, proved they were Erwinia amylovora species. Studying pathogenicity factors showed an almost direct relationship between all pathogenicity factors (other than biofilm production) and the severity of disease symptoms on tissues. The most resistant blooms tissues to D 43 isolate were shown to be related to Dargazi and Spadona pear cultivars; Duchess and Chini Hesar pear cultivars had the most resistant immature fruits tissues to D 43. It is therefore concluded that the susceptibility tissues to isolates of Erwinia amylovora were different in various cultivars. This point could help control fire blight disease and programs of breeding cultivars in the future.

SPECT-CT is an imaging method for diagnosing diseases and studying physiology of the body. In this type of imaging, due to the use of radiopharmaceutical for imaging (SPECT) and X-rays (CT), a relatively high dose of radiation is introduced into the patient. If the patient is pregnant, considering that the developing fetus is sensitive to any radiation in the uterus throughout the entire period before birth, there may be harmful and irreversible effects on the fetus; therefore protecting the pregnant woman and the fetus against radiation is of great importance. The purpose of this study is to evaluate and calculate the fetus absorption dose in cardiac imaging using the SPECT-CT machine in stress and resting conditions of the cardiac by injecting 20 mCi of radiopharmaceutical of 99mTc-MIBI.  In order to evaluate the fetus absorption dose, the Monte Carlo method, using the MCNPX code and the ORNL phantom, was applied to simulate the fetus in three, six and nine months of pregnancy, and the radiation absorbed doses of fetus absorption were calculated in two condition of stress and rest.The absorbed dose of fetus in stressed state in three, six and nine months of gestational age are 1.26 × 10-2, 2.9 × 10-3, 2.83 × 10-4  mGy respectively and The fetus absorption dose in rest in three, six and nine months of gestational age are  2.52 × 10-2, 5.79 × 10-3, 5.68 × 10-4 mGy respectively. The results of this study indicate that the highest fetus absorption dose is related to cardiac resting imaging at the third month of the fetus. The fetus absorption dose has been calculated to be less than 0.05 Gy for all maintenance periods, which, according to the NCRP 128 and ICRP 84, do not cause a serious risk to the fetus. However, special immunological advices should also be given to pregnant women to reduce the absorption of fetus, especially in the early months of pregnancy.

68Ga-PSMA-11, a novel PET radiopharmaceutical, is currently used for imaging of almost all prostate cancers. However, automatic radiolabeling procedures have been recommended. In this research, according to the chemical nature of the PSMA-11, manual, optimized and safe production of this radiopharmaceutical has been investigated and a standard method has been presented to achieve a repeatable quality with the use of an Iran made 68Ge/68Ga generator. The effect of the PSMA-11 weight, temperature, pH, and radiolabeling time on the radiochemical purity (RCP) was evaluated. The effectiveness of the optimized condition on the quality of radiopharmaceutical in 60 production series was studied according to US Pharmacopeia guidelines. Also, by monitoring the dose rate of the personnel, the safety of the manual production was checked. Increasing the temperature from room temperature (RT) to 40◦C enhanced the RCP of 10 μg of PSMA-11 to acceptable ranges of > 90%. The weights of 25 and 50 μg had RCPs>90% at RT. The appropriate pH range was determined to be 5-6. The 10 minutes’ reaction time yielded a repeatable RCP>90% for the 10 μg PSMA-11 in 60 production series. Body and hands dose rates were 15% and 2.4% of the recommended annual dose rate limit for body and hands, respectively. The results indicate the high quality of the Iran made 68Ge/68Ga generator. PET-CT centers can in-site, manually, safely and with repeatable quality produce 68Ga-PSMA-11 for prostate cancer imaging away from the challenge of transport problems.

The most serious diseases of cultivated mushrooms are caused by Pseudomonas tolaasii and Trichoderma harzianum pathogens. A common method of pathogen control on farms worldwide is the application of various chemical pesticides. Many of these substances are unsafe for human and environment. The interest in discovering and developing natural antimicrobials has significantly increased due to consumer preferences for foods that are free of chemical residues. So, a major challenge for mushroom growers is to control diseases with alternative compounds such as essential oils and plant extracts. Antimicrobial peptides (AMPs) were also known as potential antibiotic and considered as a new antimicrobial agents. In the present study, the antibacterial and antifungal potential of essential oils, plant extracts and a recombinant peptide were investigated for their pathogenicity. For this purpose, the essential oils of Cuminum cyminum and Zataria multiflora and the plant extracts of Dorema ammoniacum and Ferulago angulata and a recombinant peptide were evaluated for their antimicrobial and antifungal effects on the P. tolaasii and T. harzianum pathogens. In this study, essential oils of C. cyminum and Z. multiflora were extracted by hydrodistillation in a Clevenger-type apparatus. The plant extracts (D. ammoniacum and F. angulata) were prepared using maceration method. Recombinant peptides (Lactoferricin-Lactoferrampin) were produced from Adherent Human Embryonic Kidney 293 (HEK293). The antifungal properties of essential oils, plant extract and AMPs were studied on growth inhibition. Antibacterial activity of substances were tested against P. tolaasii via disk-diffusion method respectively. Minimum inhibitory concentration (MIC), Minimum bactericidal concentration (MBC) and Minimum fungicidal concentration (MFC) to the compounds were studied. All treatments were considered in a completely randomized block design with three replicates. The results of the antibacterial evaluations showed that the Chimera peptide have remarkable activity against pathogenic bacteria with a mean diameter of the zone inhibition region of 32.2mm, followed by C. cyminum and D. ammoniacum extracts with mean values of 7 and 6 mm respectively. Regarding to antifungal activity of substances isolated from above material, it was found that essential oils of C. cyminum and Z. multiflora completely prevent the growth of T. harzianum, followed by D. ammoniacum and F. angulate with maen values of 26 and 60.6 mm respectively. The lowest antifungal activity was observed for chimera peptide. The cultivated button mushroom is one of the most extensively cultivated mushroom in the world. The most serious diseases of cultivated mushrooms are caused by P. tolaasii and T. harzianum pathogens. The results of our study showed that the C. cyminum and D. ammoniacum have remarkable activity against pathogenic bacteria. Plant extracts, essential oils and their components have demonstrated strong fungistatic and antibacterial effects against pathogenic fungi and bacteria on cultivated mushrooms. Modes of action of essential oils in their interaction with bacteria have been quite revealed. It has been assumed that Thymol changes the permeability of cytoplasmic membrane of Gram-positive bacteria, acting as a proton exchanger, decreasing the pH gradient and causing a collapse of the proton motive force and eventually cell death. Regarding to antifungal activity, our results also showed that essential oils of C. cyminum and Z. multiflora completely prevent the growth of T. harzianum, followed by D. ammoniacum and F. angulate. One of the possible action mechanisms proposed that fungal growth may be reduced or totally inhibited due to monoterpenes present in essential oils which could increase the concentration of lipidic peroxides such as hydroxyl, alkoxyl and alkoperoxyl radicals and so bring about cell death. According to another mechanism, the essential oils would act on the hyphae of the mycelium, provoking exit of components from the cytoplasm, the loss of rigidity and integrity of the hypha cell wall, resulting in its collapse and death of the mycelium. In our study, a camel recombinant chimeric lactoferricin + lactoferrampin peptide was also tested for its antimicrobial activity. Our result showed that this recombinant peptide have remarkable activity against pathogenic bacteria. The details of the antibacterial mechanism for this recombinant peptide still are unknown. However, amino acid profile, sequence orientation and structural conformation of cationic peptides are the main features which make these peptides capable to inhibit bacterial growth by disrupting of the bacterial cell membrane. As a general results it can be concluded that natural plant-derived antimicrobial as well as recombinant peptides can be used as alternatives to synthetic pesticides, however, further studies on safety and toxicity of these substances should be carried out before use. In summary, this study shows that essential oils and plant extracts isolated from above plant material have remarkable antifungal activities against T. harzianum, while the chimera peptide showed complete inhibition against P. tolaasii. Thus all of these substance could become alternative to synthetic antimicrobial compounds for control of mushroom pathogens. However, further studies on safety and toxicity of these substances should be carried out before use.

In the present study, antimicrobial effects of the ethanolic herbal extracts of seven medicinal plants including Absinthe, Chamomile, Cumin, Asafoetida, Gum tree, Balm and Tree of heaven against Erwinia amylovora bacterium were investigated. Virulence assay of the bacterial isolates on the immature pear fruit of the Spadona pear cultivar was performed, and the most pathogenic bacterium isolate was selected for further evaluation. Sensitivity of the selected isolate to two copper compounds and five antibiotics was examined. Antibacterial properties were assessed at three concentrations using the disk-diffusion method. To investigate the synergistic effect of the plant extract with copper compounds, the extract of Balm, which have been indicated maximum antibactericidal effect was used. The Balm plant extract was also tested on the seedling of Spadona pear. The ethanolic extract of Balm had the most significant antibacterial effects with the mean inhibition zone diameter of 15.66 mm against the GA3 isolate. The bactericidal effects were not exerted by Chamomile and Heaven tree. Moreover, the results indicated no synergistic effects in the plant extracts of Balm and the tested copper compounds. Our results demonstrated the positive stimulating effects of the plant resistance system by the Balm extract. Evaluation of guaiacol peroxidase at seven different intervals indicated the elevated level of GPX within the first 24 hours compared to the control and bacterial treatment. The results of this research can introduce novel suggestions for future researches in order to control fire blight disease of pome fruit trees via using active components of medicinal plants.

Poor lubrication is known as an important factor in the bearings failure. Therefore, it is very important to detect the lubrication condition. Hydrodynamic lubrication, mixed lubrication and boundary lubrication are the basic regimes of the fluid film lubrication. In a proper condition, development of hydrodynamic pressure is adequate to support the load and the bearings operate under hydrodynamic lubrication condition. However, in most situations, they operate in mixed lubrication or boundary lubrication regime and have metal-to-metal contact. To establish these regimes, using the so-called Stribeck curve is a useful method. In this curve, the oil film thickness is proportional to the lubricant viscosity and sliding velocity and inversely proportional to the applied load. However, distinguish of the exact range of hydrodynamic lubrication regime from mixed and boundary regime using this curve and relation related to the sliding bearings, due to high number of affecting design factors and operating parameters is difficult. The present study focused on the acoustic emission measuring method in order to monitoring the lubrication conditions in a type of journal bearings. Thus, condition monitoring of the journal bearing lubrication is provided and the numerical value of operating variables of the bearing for lubrication regime change from hydrodynamic to mixed is achieved. Using wavelet method, frequency features for each regime is identified. Then, for each lubrication regime, metal-to-metal contact detection is performed.

In recent years brown blotch of cultivated mushroom (Agaricus bisporus) has been observed as a prevalent disease in Iran. The disease symptoms of the cultivated agaric include brown blotch, brown pit spots, rotting, weeping and drippy gill. Pseudomonas tolaasii has been cited as the causal agent of bacterial blotch, but much controversy exists regarding the involvement of this bacterium alone or blotch may be caused by more than one organism. In 2011, the diseased samples of mushroom were collected from Khorasan Razavi, Alborz, Tehran, Semnan, Ghazvin and Golestan provinces. Strains which were pathogenic on the cap of mushroom (pileus) were selected for further analysis. Biochemical, physiological and nutritional tests together with amplification of 1Kb region of 16S rDNA using Ps forward and reverse primers showed that all strains belong to Pseudomonas tolaasii. The isolated strains displayed different degrees of pathogenicity on mushroom. The presence of different virulence factors were evaluated among the strains. The results indicated that those strains which showed enhanced pyoverdin production had higher pathogenicity on agaric caps. There was no correlation between the existence of other virulence factors such as biofilm formation, motility, or PQS production and pathogenicity. Our results indicated that in P. tolaasii similar to other Pseudomonads, PQS exists but the actual role of this signal is not so clear. PQS dependent quorum sensing in P. tolaasii could not affect pathogenicity of this bacterium, thus most of the virulence determinants in this bacterium should be PQS independent.

In recent years several studies have been done in the field of laminar flame speed. One of the important characteristics of the combustion is the laminar flame speed. In this study, the effects of CO2 and N2 on the laminar flame speed of natural gas and gasoline fuel mixture have been investigated. Schlieren method has been used in this study. Experiments were carried out at pressure of 1 bar and 363 k in constant volume chamber. The mass fraction of CO2 and N2 varied from 0% to 12%.The result shows laminar burning velocity and the adiabatic flame temperature decrease with the adding CO2 and N2 Specific heat capacity of CO2 more than N2, for this reason the laminar burning velocity of N2 more than CO2. Also the result shows Addition of CO2 and N2 does not cause much change in stability.

Nowadays, utilization of blended fuel in internal combustion engine is one of main topics in vehicle industries. The synergy effect will be highlighted when the potential of each fuel is employed and the engine performance will improve consequently. In this research, the laminar flame speed of methane (main component of reference fuel for Natural gas) and isooctane (main component of reference fuel for gasoline) and their blended fuel, as an intrinsic characteristic of combustible mixtures is measured. Isooctane and methane with two volumetric fractions of 70% and 95% in blended are added in constant volume combustion chamber with partial pressure method in three temperature of 368, 408 and 448K and three pressure of 1, 2.5 and 5 bar. After filling the chamber in specified fuel air ratio, the mixture is ignited at the center of chamber and flame propagation is recorded with schlieren method. Laminar flame speed and Markstein length are calculated via post processing of flame images. Numerical simulation of flame speed is done using CHEMKIN code. Finally, a correlation based on temperature, pressure, equivalence ratio and methane mass fraction in blended fuel is proposed which predict the flame speed well.

In recent years, natural gas and gasoline blended fuels have been considered as alternative fuels in spark ignition (SI) engines. In order to utilize their potential benefits, a precise identification of those alternative fuels is attractive and inevitable studies to predict their performance in SI engines. In this study, the laminar flame speed of natural gas and gasoline blended fuels in the constant volume chamber at different equivalence ratios of 0.8 to 1.2, via the Schlieren optical method was measured and the un-stretched laminar flame speed by following the theory of the weekly stretched flame was obtained. Direct injectors, were installed at the top of the chamber and were used to inject liquid and gaseous fuels. To ensure that the liquid fuel would evaporate completely, the chamber wall was heated with four band heaters and liquid injection was done in the vacuumed chamber. The result showed that adding the natural gas to the gasoline would increase its flame speed at low equivalence ratio, from 0.8 to 0.95. Adding the natural gas to the gasoline in high equivalence ratio caused the flame instability that originated from cracking and the cellularity of the flame surface occurred at higher equivalence ratio.

[61Cu]Bleomycin ([61Cu]BLM) was prepared using [61Cu]CuCl2 produced via natZn(p,x)61Cu (180μA proton irradiation, 22MeV, 3.2h), purified by ion chromatography method. [61Cu]BLM was prepared at optimized conditions (room temperature, 45 min, 0.1 mg bleomycin for 2-10mCi 61CuCl2) with radiochemical purity over 98% determined by HPLC and RTLC. [61Cu]BLM was administered into the normal and tumor bearing rodents up to 210 minutes followed by biodistribution and co incidence imaging studies. A significant tumor/non tumor accumulation was observed either by animal sacrification or imaging method. [61Cu]BLM can be a potential PET radiotracer for tumor imaging.

Backgraound: Hypoxia is an important determinant for biological behavior of malignant solid tumors. In vitro and in vivo studies have shown that tumor hypoxia is associated with an increased likelihood of local recurrence and distant metastasis, as well as resistance to radiation therapy and certain types of chemotherapy. Studies have shown that some copper-bis thiosemicarbazones especially, Cu-ATSM accumulates avidly in hypoxic cells, but washes out rapidly from normoxic cell.

[61Cu]-diacetyl-bis (N4-methylthiosemicarbazone) ([61Cu]-ATSM) was prepared using house-made ATSM ligand and [61Cu]CuCl2 produced via the natZn(p,x)61Cu (180¼A proton irradiation, 22MeV, 3.2h) and purified by ion chromatography method. [61Cu]-ATSM was administered into normal and tumor bearing rodents up to 180 minutes followed by biodistribution and co-incidence imaging studies.

Radionuclidic control showed the presence of 67.41(4.23%), 282.96(12.2%), 373(2.15%), 511(122.9%), 656(10.77%), 1186(3.75%) keV-rays from 61Cu and showed a radionuclidic purity higher than 99%. The rest of activity was attributed to 60Cu (0.23%). [61Cu]-ATSM radiochemical purity was >99% shown by HPLC and RTLC methods. A significant difference was observed between tumor and non tumor accumulation.

The method used in this research for the production and chemical separation of 61Cu was simple and cost effective. [61Cu]-ATSM is PET radiopharmaceutical for hypoxia imaging with an intermediate half life, and our experiments on this radiopharmaceutical have shown satisfactory results, suitable for future PET studies in human.

Gallium-67 labeled superparamagnetic iron oxide nanoparticles ([67Ga]-SPION) were prepared and evaluated for their altered biodistribution in normal rats. SPIONs with narrow size distribution were synthesized by co-precipitation technique using ferric and ferrous salts at molar ratio Fe3+/Fe2+=2:1 followed by structure identification using XRD, TGA, DSC, VSM, HRSEM, TEM and FT-IR techniques. In order to trace SPION bio-distribution, the radiolabeled iron oxide nanoparticles were prepared using 67Ga with a high labeling efficiency (over 96%, determined by RTLC method) and they also showed an excellent stability at room temperature for at least 4 days. The biodistribution of the radiolabeled SPION was checked in normal male rats up to 24 hours compared with the free Ga3+ cation biodistribution. The data strongly support the alteration of the tracer accumulation in reticuluendothelial system while the stability of the complex is highly retained. The result is promising for determining the position of the nanoparticles injected into a tissue when hyperthermia treatment/imaging is applied in biomedical fields.

Concentration of kryptofix 2.2.2 in [18F]FDG solutions and standard solutions of kryptofix 2. 2.2 was determined by two methods Visualization of combination of K2.2.2 with iodine vapor and iodoplatinate reagent. In both methods, concentration difference of K2.2.2 solutions was appeared as difference in color intensity of revealed spots on TLC. The detection limit of K2.2.2 by iodine vapor and iodoplatinate reagent is 25 and 2 ppm, respectively. Both methods can be used to release or reject the quality of [18F]FDG radiopharmaceutical for intravenous injection, but the second method is more suitable because of taking shorter time.

Trace amounts of cobalt-57 were separated from nickel and extracted into isopherone in the presence of thiocyanate as a complexing agent. The effect of various parameters on the separation yield was investigated. These include: concentration of the complexing agent, aqua and organic phases volume ratio and acidity of aqua phase. The extracted cobalt-57 was backextracted into concentrated hydrochloric acid and the effects of hydrochloric acid concentration and volume on backextraction yield were investigated. 4% (W/V) ammonium thiocyanate solution, pH=1.5-2 and lower organic to aqua volume ratio gives the highest separation yield. 99.57% backextraction yield was achieved for cobalt-57 through 5 steps of washing with 5 N HCl.

[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 Benzyl-14-tosyloxy-6-thia-heptadecanoate 1 in one step at 90C in 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.