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Random Amplified Polymorphic DNA (RAPD) technique is a powerful tool for genetic studies. It can be also applied for determination of bacterial species. The goal of this work was to optimize conditions for RAPD reaction, and to obtain RAPD patterns specific for some plant-associated bacteria. RAPD could be a good choice for screening and preliminary bacterial determination. Application of RAPD can determine that some of bacterial species are not reason of infection, and make additional tests for them unnecessary. This can provide time, labor, and as well as money saving, which is important particularly if expensive tests are applied. Optimization of reaction conditions in this work made possible good repeatability of RAPD electrophoretic patterns for particular bacterial species.

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Abstract  

In radiochemical analysis, specially by using high resolution alpha-spectrometry, a key issue is the determination of the radiochemical yield. Radiochemical yield allows to determine the concentration of the radionuclide of interest and the quality of the chemical separation. To determine the radiochemical yield it is necessary to know the solid state detector efficiency, which can be obtained by calibration with a circular calibrated source. In this paper the optimization of the parameters affecting both the calibration and measurement of a source by alpha-spectrometry is described. The optimization is based on two sets of data: experimental and theoretical. Experimental data were obtained from the calibration of the solid state detector with four calibrated 241Am sources. Theoretical data were calculated by geometry formulas and were verified experimentally.

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Analytical as well as computer aided thermal optimization of a construction of a stripegeometry double-heterostructure GaAs/(AlGa)As diode laser were performed in the present work. The influence of various construction parameters of the laser on its thermal resistance is shown.

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Excitation functions fornatZn (p, xn) and (p, pxn) nuclear reactions in the 5–45 MeV proton energy range were measured. Evaluations were made both of target thickness and proton energy in order to optimize the67Ga production rate, at the same time minimizing contamination by the66Ga. Optimal irradiation conditions, depending both on the beam current available and on the power dissipated into the target were determined.

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Journal of Flow Chemistry
Authors: Gábor Máté, Dezső Szikra, Jakub Šimeček, Szandra Szilágyi, György Trencsényi, Hans-Jürgen Wester, István Kertész, and László Galuska

The synthesis and functional evaluation of a wide variety of radiolabeled chelator–biomolecule conjugates with high specific activity and radiochemical purity are crucial to development of personalized nuclear medicine. An excellent platform technology for achieving this objective involves use of generator-produced positron emission tomography (PET)-radionuclide 68Ga. Currently, applied manual methodology for optimization and development for new labeling techniques offers only slow screening with relatively high precursor consumption. A capillary-based microfluidic synthesis module with online high-performance liquid chromatography (HPLC) was constructed for the optimization of reaction parameters of 68Ga-PET tracers. This approach enables performance of 68Ga-labeling reactions in 10 μL volumes, followed by sample analysis. The high-throughput capacity of the system allows very rapid optimization. The optimal pH and ligand concentration from the experiments were utilized directly to the production of 68Ga-NODAGA-(RGD)2 and 68Ga-NOPO-RGD. Applying optimal parameters to production of these aforementioned radiopharmaceuticals allowed their synthesis with high radiochemical purity (over 95%) and with surprisingly negligible retention of residual activity in the system.

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In radiological emergency, rapid determination of radiostrontium will be necessary. The required quantification levels will be relatively high which offers smaller sample sizes and shorter ingrowth and counting times. In this paper a rapid method for the determination of 90Sr in fresh milk in emergency preparedness is presented. The method is based on microwave digestion, chemical separation of Sr, ingrowth of 90Y and Cherenkov measurements. In order to minimize the total analysis time, a mathematical model was developed. For a given number of samples the model minimizes the analysis time by optimizing the ingrowth and counting time in order to reach a detection limit fit-for-purpose.

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In order to optimize the infrared extinction of a SiC-powder in a silica powder matrix, Mie scattering calculations for spherical SiC-particles have been performed. A single oscillator-model was applied to calculate the optical constants of SiC. Taking into account the particle size distribution of a commercially available SiC-powder, its wavelength dependent extinction coefficient was calculated. The result is in very good agreement with the extinction spectrum of the powder derived by infrared optically measurements. Mie scattering theory also was used to find the optimum mean SiC-particle diameter of a mixture of 20% SiC-powder and 80% silica powder.

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Bombesin (BNN)-like peptides have very high binding affinity for the gastrin-releasing peptide (GRP) receptor. The goal of the current study was to optimize the labeling conditions of a new 99mTc-radiolabeled BNN-like peptide based on the bifunctional chelating ligand HYNIC using different co-ligands (EDDA and tricine). The radiolabeling conditions (pH, amount of co-ligand, amount of stannous chloride, temperature and reaction time) for newly-formed 99mTc-tricine-HYNIC-Q-Litorin and 99mTc-EDDA-HYNIC-Q-Litorin were optimized and evaluated by RHPLC and RTLC. Radiochemical yields for 99mTc-tricine-HYNIC-Q-Litorin and 99mTc-EDDA-HYNIC-Q-Litorin were 98.0 ± 1.7 and 97.5 ± 2.5%, respectively. When EDDA was used as co-ligand, the labeling of 99mTc-EDDA-HYNIC-Q-Litorin was optimal in the following reaction mixture: HYNIC-peptide: EDDA: 10 μg/5 mg, pH 3, SnCl2 concentration: 12 μg/0.1 mL, reaction temperature: 100 °C, reaction time: 15 min. Besides, the optimum conditions were HYNIC-peptide:tricine: 10 μg/50 mg, pH 5, SnCl2 concentration: 12 μg/0.1 mL, reaction temperature: 100 °C, reaction time: 15 min for preparing 99mTc-tricine-HYNIC-Q-Litorin. The manufactured 99mTc-HYNIC-Q-Litorin conjugates may offer new possibilities for imaging cancer cells expressing bombesin receptors.

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Summary  

[125I]iodepidepride, (s)-(-)-[(1-ethyl-2-pyrrolidinyl)methyl]-5-[125I]-iodo-2,3-dimethoxybenzamide is the iodine substituted analogue of isoremoxipride, both of which are very potent dopamine D2-antagonists. Epidepride was radioiodinated using different oxidizing agents such as chloramine-T, iodogen, iodogen glass frit and hydrogen peroxide. Chloramine-T is a powerful oxidizing agent compared to both iodogen and hydrogen peroxide so that the side products, especially the chlorinated epidepride, decreases the radiochemical yield. This chlorinated epidepride is minimized in the case of iodogen and iodogen glass frit and are not observed in case of the non-chlorinated oxidizing agent hydrogen peroxide. TLC and HPLC were used to analyze the reaction components and to estimate both the radiochemical yield and purity. The reaction parameters such as reaction time, pH, epidepride and oxidizing agent concentrations and the stabilty of the final product were studied to optimize the radiochemical yield and purity. The optimized radiochemical yield was about 90% and the radiochemical purity of the final product was 99.9%.

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Mercury, a known neurotoxin, has been implicated in the etiology and pathogenesis of such disease states as Alzheimer's and Parkinson's diseases. There is concern that the exposure to mercury vapor released from dental amalgam restorations is a potential health hazard. Measurement of mercury concentrations in blood or urine may be useful in diagnosis of mercury poisoning and in assessing the extent of exposure. This study describes the optimization of pre-neutron activation analysis procedures such as sampling, selection of irradiation and counting vials and acid digestion in order to minimize mercury loss via volatilization and/or permeation through containers. Therefore, the determination of mercury can be complicated by these potential losses. In the optimized procedure 20 mL of urine was spiked with three different concentrations of mercury, digested with concentrated nitric acid, and placed in polypropylene vials for irradiation and counting. Analysis was performed by subtracting the Se-75 photopeak contribution to the 279 keV Hg-203 photopeak and applying the method of standard additions. Urinary mercury concentrations in normal human subjects were determined to be of the order of 10 ng/mL.

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