Ergosan contains 1% alginic acid extracted from two brown sea weeds. Little is known about the target organs and anatomical distribution of Ergosan (alginic acid) in fi sh. Therefore, feasibility of developing alginic acid nanoparticles to detect target organ in rainbow trout is interesting. To make nanoparticles, Ergosan extract (alginic acid) was irradiated at 30 kGy in a cobalt-60 irradiator and characterized by transmission electron microscopy (TEM) and Fourier transform infrared spectroscopy (FTIR). Results from TEM images showed that particle sizes of irradiated alginic acid ranged from 30 to 70 nm. The FTIR results indicated that gamma irradiation had no signifi cant infl uence on the basic structure of alginic acid. Later, alginic acid nanoparticles were successively labelled with 67Ga-gallium chloride. The biodistribution of irradiated Ergosan in normal rainbow trout showed highest uptake in intestine and kidney and then in liver and kidney at 4- and 24-h post injection, respectively. Single-photon emission computed tomography (SPECT) images also demonstrated target specifi c binding of the tracer at 4- and 24-h post injection. In conclusion, the feed supplemented with alginic acid nanoparticles enhanced SPECT images of gastrointestinal morphology and immunity system in normal rainbow trout.
2
Dostęp do pełnego tekstu na zewnętrznej witrynie WWW
Northern Sweden is dominated mainly by Paleoproterozoic rocks. Igneous activity during the Svecofennian orogeny (1.93-1.87 Ga) created vast amounts of both volcanic and plutonic rocks within and around the Archaean craton. Post-orogenic 1.80-1.77 Ga granitoids were formed later within the same region, it has Distinguishing between the different mafic and ultramafic members of such plutonie suites was proven problematic during bedrock mapping . Geochronology may be of use to discriminate between suites; however, it is not a cost-efficient method for dealing with large amount of samples. The mafic and ultramafic rocks have three dominating suites, the Haparanda suite (1.94-1.85 Ga), the Perthite-monzonite suite (PMS) (1.87 Ga) and the Edefors suite (1.80-1.79 Ga). This study focuses primarily on Rare Earth Elements (REE's) and trace element geochemistry to trace the distribution and distinguish between the three mafic and ultramafic suites as a tool for geochemical mapping of the northern bedrock. Lithogeochemical data (e.g. major elements, REEs and trace elements) covering the majority of northern Sweden gathered during bedrock mapping was provided by the Geological Survey of Sweden (SGU). Plutonic rocks ranging from gabbros to quartzdiorites and monzonites comprised nearly 80 analyses. Normalized spider plot patterns of REEs and trace elements served as a basis for subdivision into groups by similarities in key identification parameters. Several patterns are characterized by a pronounced Eu - trough while the middle - to HREEs display a rather flat trend, criteria that are related to rocks from the Haparanda suite, while samples with positive Eu-anomaly (Eu/Eu* > 1) and a nearly flat trend from La to Pr with a marked positive peak at Sr and generally less enriched in LILE, are consistent with the Edefors suite. An approximately uniformly depleted trend throughout the HREE with a slight concave upward shape from the LREEs towards the HREEs and an apparent enrichment in Sr and Nd and depletion in P could relate to either the Haparanda or the PMS suite. Among the others, statistical methods will be used to compare the correlation between the REEs within the datasets to find suitable elements for further analysis and thereby assigning the groups to appropriate suites, thus, the distribution of rock based on key tracers for related suites will be presented accordingly.
Targetry of natSn-target on Cu substrate was investigated for the production of 117,118m,119,120m,122Sb. The electrodeposition experiments were carried out using potassium stannate trihydrate and potassium hydroxide. The optimum conditions of the electrodeposition of tin were as follows: 40 g/L natSn, temperature 75°C and current density (dc) used throughout of 50 mA/cm2. The deposited target was irradiated at 160 ěA current and 16 MeV proton beam (10 min). Separation of no-carrier-added (nca) 117,118m,119,120m,122Sb from the irradiated natSn target hydrochloric solution was investigated using silica-gel column chromatography.
85Sr was produced via the 85Rb(p,n)85Sr reaction. Rubidium chloride deposition on copper substrate was carried out via the sedimentation method in order to produce strontium-85. Optimum conditions were achieved as a result of several repeated experiments with different amount of ethyl cellulose (EC) and acetone. 520 mg of RbCl, 208 mg of EC 4 mL of acetone were used to prepare a layer of enriched rubidium chloride of 11.69 cm2 area and 62.2 mg/cm2 thickness. Target quality control was done by a SEM photomicrograph and a thermal shock test. The deposited target was irradiated at a 20 ěA current and a 15 MeV proton beam for 30 min. No degradation was observed. The RbCl surface following bombardment was white, except the central area that was light brown and also without any crack or peeling off.
Positron emission tomography (PET) is a powerful diagnostic tool, which provides superior spatial resolution and an opportunity to obtain quantitative information concerning distribution of radioactivity in vivo. Most interesting positron emitters for the purpose of diagnose are 64Cu, 124I, 18F, 86Y, 48V, 52Mn, 140Pr, 72As, 74As, 89Zr, 82Sr, 68Ga, 66Ga, 45Ti, 76Br and 82Rb. Aim of the presented study is to compare the calculated cross sections of several radioisotopes of positron emitters as follows 86Y, 43Sc, 64Cu, 66Ga and 76Br with incident proton energy up to 30 MeV. In this work, excitation function of positron emitters via the 86Sr(p,n)86Y, 43Ca(p,n)43Sc, 66Zn(p,n)66Ga, 64Ni(p,n)64Cu and 76Se(p,n)76Br reactions were calculated by ALICE/ASH 0.1 (GDH model and hybrid model) and TALYS-1.2 (equilibrium and pre-equilibrium) codes and compared to existing data. Requisite for optimal thicknesses of targets were obtained by the stopping and range of ions in matter (SRIM) code for each reaction.
The efficiency of cooling and the particle beam characteristics are important when high beam current irradiations are intended for production of radionuclides. The efficiency of cooling is determined by both the target carrier geometry and the flow rate of coolant, while the beam characteristics deal with the current density distribution on the irradiated surface area. Heat transfer on rhodium target to produce 103Pd via the 103Rh(p,n)103Pd reaction was investigated and the beam current was obtained more than 500 mi A.
The IsoAid LLC Inc. has been introduced ADVANTAGETM 103Pd brachytherapy seed in 2006. The aim of this work is to determine the dosimetric characteristics of this seed according to AAPM’s recommendation in TG43-U1 using MCNP4C computer code. The dose rate constant has been determined to be 0.694š0.001 cGy.h–1.U–1. The radial dose function has been calculated at distances from 0.25 to 7 cm. Two-dimensional anisotropy function have been calculated at distances from 0.25 to 7 cm and at angles from 0 to 90 degrees centigrade at 10 degrees centigrade increments. The one-dimensional anisotropy function and anisotropy constant have been also calculated. The anisotropy constant in water has been calculated as 0.872š0.001. The results of this investigation are compared with the results of Meigooni et al. obtained by PTRAN code in 2006 and Sowards results obtained by PTRAN code in 2007. The comparison of the dose rate constant and the one-dimensional anisotropy function obtained from the two codes shows good agreement; also the radial dose function at distances lower than 3 cm and the two-dimensional anisotropy function at angles greater than 20 degrees centigrade are in good agreement. But, for the calculated radial dose function at distances beyond 3 cm, we observed differences between our values and Meigooni et al. and Sowards results. Also, differences between the calculated two-dimensional anisotropy function using the two codes for angles smaller than 20 degrees centigrade are considerable. The differences between the results of MCNP4C and PTRAN codes could be related to the different cross-section data libraries used in these two codes.
68Ga is an important positron-emitting radionuclide for positron emission tomography. In this work 68Ga was produced via the 68Zn(p,n)68Ga nuclear reaction. 68Zn electrodeposition on a copper substrate was carried out by alkaline cyanide baths. 68Zn target was irradiated with a 15 MeV proton beam and a 150 mi A current. The production yield achieved was 136 mCi/ mi Aźh (5.032 GBq/mi Aźh). 68Ga was separated from zinc and copper by a combination of cation exchange chromatography and liquid-liquid extraction methods.
Zinc-68 electrodeposition on a copper substrate was investigated for the production of 64Cu radionuclide. The electrodeposition experiments were carried out by acid plating baths. Operating parameters such as pH, temperature, and current density are also optimized. The current efficiency was measured at different current densities. The optimum conditions of the zinc electrodeposition were as follows: 6.2 gźl-1 zinc, pH = 3, dc current density of ca. 85.54 mAźcm-2 at 30°C with 98% current efficiency. SEM photomicrographs demonstrated fine-grained structure of the deposit obtained from the optimum bath.
Geometry function is the only dosimetry parameter of a brachytherapy source seed, introduced in TG-43U1 protocol which is determined using calculational methods rather than physical measurement. In order to evaluate the accuracy of point and line source approximations, for calculation of the geometry function, the MCNP computer code has been used for a typical brachytherapy seed and the results have been compared. The MCNP has been used to simulate the geometry and activity distribution of a Pd-103 seed in order to calculate the geometry function for various angles and distances from the source. The comparison of results shows that at distances close to the source, the values predicted with different methods are not in agreement. The difference between the MCNP calculations and line approximation for small angles from ? = 0 to 15° is about 27% at 0.25 cm from the seed center. This difference is so much higher for point source approximation (up to a factor of 3) even up to distances of 0.5 cm from the source. As ? increases, the difference between MCNP and approximate methods is reduced. Therefore, for small distances from brachytherapy seeds, it is recommended to calculate the geometry function using more detailed methods instead of point and linear source approximations. This will provide more accurate results for other TG-43U1 dosimetry parameters such as radial dose function or anisotropy function which for some points are calculated via interpolation or extrapolation of the available discrete dosimetry data.
Samozorganizowane kropki kwantowe wykonano z InGa/GaAs na podłożu (100) GaAs metodą epitaksji z wiązek molekularnych w modzie Strańskiego-Krastanowa techniką przerywanego wzrostu. Do charakteryzacji kropek i oceny ich jednorodności wykorzystano mikroskop sił atomowych. Analiza statystyczna rozmiarów kropek wykazała bimodalny rozkład wielkości, który wskazuje na obecność dwóch grup kropek kwantowych istotnie różniących się wymiarami i gęstością. Dominująca grupa kropek miała wymiary 5,9 i 35,4 nm odpowiednio dla wysokości i średnicy, a niejednorodność w stosunku do średnich rozmiarów była na dobrym poziomie 10%. Natomiast duże kropki były bardzo nieregularne, jednak miały małą gęstość powierzchniową około 1 × 109 cm-2 i o rząd wielkości mniejszą w porównaniu do gęstości mniejszych kropek kwantowych. Technika przerywanego wzrostu w zoptymalizowanych warunkach pozwala uzyskać grupę dobrze zdefiniowanych kropek kwantowych.
EN
Self-organized InAs/GaAs quantum dots were prepared on (100) GaAs substrates by a solid source molecular beam epitaxy in Stranski-Krastanov growth mode using growth interruption technique. Atomie force microscopy was used to characterize the dots and to conclude on the dot size uniformity. Statistical analysis of the dot size variation revealed a bimodal size distribution, which indicates the presence of two dot families differing significantly in their size and density. The dominating dots were 5.9 and 35.4 nm in height and diameter, respectively and were uniform to within 10% of the average sizes. By contrast larger dots were extremely irregular however, they were fo-und at a Iow areał density of about 1 × 109 cm-2, which was one order of the magnitude lower comparing to density of the smaller dots. On the basis of the obtained results, it is concluded that the growth interruption technique is a powerful tool in obtaining well defined quantum dots when growing under optimized conditions.
Due to the anticancer properties of bleomycin (BLM) complexes, production of [103Pd]bleomycin ([103Pd]BLM) was targeted. Palladium-103 (T1/2 = 16.96 d) was produced via the 103Rh(p,n)103Pd nuclear reaction using a natural rhodium target. Proton energy was 18 MeV with 200 mA irradiation for 15 h (final activity 25.9 GBq of 103Pd2+, RCP > 95%, radionuclidic purity > 99%). 103Pd was separated from the irradiated target by anion exchange using a Dowex 1´8 (Cl-)/100-200 mesh resin in the form of Pd(NH3)2Cl2 in order to react with bleomycin to yield [103Pd]BLM. Chemical purity of the final product was in accordance to the accepted limits. [103Pd]BLM was prepared with a radiochemical yield of more than 98% at 80°C in 30 min. The labeling reaction was optimized for time, temperature and ligand concentration. Radiochemical purity of more than 99% was obtained using RTLC with specific activity of about 370 MBq/mmol. The stability of the tracer was checked in the final product and presence of human serum at up to 3 h. The complex was stable in human serum at 37°C up to 2 h of incubation. Biodistribution studies using a SPECT system performed in normal rats in the first 2-3 h.
Thallium-201 (T1/2 = 3.04 days) in Tl+ form was converted to Tl3+ cation in presence of O3 in 6 M HCl controlled by RTLC/gel electrophoresis methods. The final evaporated activity was reacted with vancomycin (VAN) in water to yield [201Tl](III)VAN. The best results were obtained at room temperature in water after 30 min with a radiochemical yield > 99%, after mixing the reactants followed by SPE purification using Si Sep-Pak. The studies showed that thallic ion is mostly incorporated into vancomycin with a radiochemical purity of more than 98 š 1% by RTLC. A specific activity of about 4.14 x 1010 Bq/mmol was obtained. Radiochemical purity and stability of 201Tl-VAN in the preparation and in presence of human serum was determined up to 5.5 days. Biodistribution study of 201Tl(III)-vancomycin in normal rats was performed up to 52 h.
JavaScript jest wyłączony w Twojej przeglądarce internetowej. Włącz go, a następnie odśwież stronę, aby móc w pełni z niej korzystać.