Four terbium isotopes 149,152,155,161Tb emitting various types of radiation can be used for both diagnostics and therapy. 152Tb emits positrons and is ideal for PET. 155Tb is considered a promising ...Auger emitter and a diagnostic pair for other terbium therapeutic isotopes. Several methods for the production of 155Tb using charged particle accelerators have been proposed, but they all have significant limitations. The restricted availability of this isotope hinders its medical applications. We have proposed a new method for production of 155Tb, irradiating enriched 155Gd by alpha particles. The possibility of simultaneous production of two isotopes of terbium, 152,155Tb, was also studied for more efficient cyclotron beam use.
Irradiation of 155Gd enriched targets and 155Gd / 151Eu tandem target with alpha-particles with an energy of 54 MeV was carried out at the U-150 cyclotron at the NRC “Kurchatov Institute”. The cross sections of nuclear reactions on enr-155Gd were measured by the stack foil technique, detecting the gamma-radiation of the activation products. The separation of rare earth elements was performed by extraction chromatography with the LN Resin. 155Tb was produced via 155Dy decay.
The cross sections for the 155,156Tb and 155,157Dy production were measured by the irradiation of a gadolinium target enriched with the 155Gd isotope with alpha-particles in an energy range of 54 → 33 MeV. The yield of 155Dy on a thick target at 54 MeV was 130 MBq/μAh, which makes it possible to obtain 1 GBq of 155Tb in 11 h-irradiation with 20 μA beam current. The possibility of simultaneous production of 152,155Tb by irradiation of 155Gd and 151Eu tandem target with medium-energy alpha-particles is implemented. Optimal irradiation energy ranges of alpha -particles as 54 → 42 MeV for 155Tb and 42 → 34 MeV for 152Tb were suggested. Product activity and radionuclidic purity were calculated.
New nuclear data relevant to the production of 155Tb were obtained. The proposed tandem target approach allows for increasing the availability of medical radioisotopes 152,155Tb.
Display omitted
Separation technique of rhenium radioisotopes from a deuteron-irradiated tungsten target of natural isotopic composition has been developed. The irradiated tungsten powder was dissolved in a mixture ...of H
2
O
2
and NaOH, the solution was passed through a column filled with an extraction chromatographic sorbent TEVA Resin. Rhenium was eluted with 4 M nitric acid. The separation procedure takes approximately 3 h, the radiochemical yield of rhenium is more than 97%.
155Tb (T1/2 = 5.32 d) is considered both as a promising Auger electron emitter and as a diagnostic pair for other therapeutic terbium radionuclides. Despite several methods for its production ...proposed, it remains scarcely available. Most of the methods using low-energy protons and deuterons beams result in a high content of radionuclidic impurities. High purity 155Tb can be obtained using high-energy proton beams combined with online mass separation of products, but the method remains inaccessible to most potential consumers. We have proposed an indirect method for the production of 155Tb via formation of 155Dy (T1/2 = 9.9 h), which can be implemented using medium energy alpha particles beam.
Gadolinium oxide targets of natural isotopic composition were irradiated by 60 MeV alpha particles beam on a U-150 cyclotron of the National Research Center “Kurchatov Institute”. The cross sections of nuclear reactions were measured by the stack foil technique, detecting the gamma radiation of the activation products. Gd, Tb, and Dy were separated by extraction chromatography using the LN Resin sorbent in nitric media. The isolated dysprosium fraction was stored for a day, and the formed 155Tb was isolated by the same method.
The cross sections for the formation of 159Gd, 153-156Tb, and 155,157Dy under irradiation by alpha particles of a gadolinium target of natural isotopic composition in the energy range 20–60 MeV have been measured. The 155Dy yield on a thick target at 60 MeV was 35 MBq/μAh, which makes it possible to obtain 1 GBq 155Tb as a result of 12-hour irradiation with a beam current of 50 μA. Extraction chromatography on LN Resin sorbent in nitric enabled quick and efficient separation of Gd, Tb, and Dy. The radiochemical yield of Dy was 95%, for Tb > 95%. The main radionuclidic impurity is 153Tb (T1/2 = 2.34 d; <5.4% of 155Tb activity).
The developed method allows the production of therapeutic amounts of 155Tb with acceptable radionuclidic purity without the need for isotopically enriched materials.
The amount of 155Tb is sufficient for its use in Auger therapy, as well as for preclinical studies of the suitability of SPECT preparations in laboratory animals. Nevertheless, to obtain higher activities, a longer irradiation time and a higher projectile current are proposed.
The 153Tb radionuclide present in the final preparation has a shorter half-life than the target radionuclide, and its hard γ-lines have a probability of emission of less than 1%, from which it can be concluded that the negative effect will not be significant. However, a product of this purity and type of contamination requires additional testing for toxicity in living organisms. The final sample also includes a certain amount of 157Tb (T1/2 = 71 a, the only γ-line 54.5 keV Iγ = 0.0084%), which will complicate the labeling conditions. Thus, more research is needed in the labeling area.
It should be noted that the use of gadolinium enriched in the 155Gd or 156Gd nuclide as a target will help not only reduce the amount of impurities but also increase the yield of 155Tb.
Display omitted
Abstract
Method for production of alpha emitter
149
Tb by irradiation of
151
Eu with 70 MeV
3
He nuclei is proposed. For the first time, the cross sections for the formation of isotopes
...149,150,151,152
Tb were measured experimentally using a stack foil technique in the
3
He particles energy range 70 → 12 MeV. The thick target yield of
149
Tb is 39 MBq/μAh, or 230 MBq/μA
149
Tb at saturation. The optimal energy range from the point of view of radioisotopic purity is 70 → 40 MeV. At these conditions about 150 MBq/μA
149
Tb can be produced in 8 hours irradiation, which is sufficient for therapeutic applications. The main impurities are
150
Tb (~100% in activity) and
151
Tb (~30% in activity). The proposed method surpasses its counterparts by the high content of the target isotope in the natural mixture and the simplicity of the radiochemical separation of
149
Tb from the bulk target material.
The complex of the short somatostatin analog, DOTA—Phe—D-Trp—Lys—Thr—OMe (DOTA is 1,4,7,10-tetrraazacyclododecane-1,4,7,10-tetraacetic acid), with the theragnostic
155
Tb radionuclide was obtained ...for the first time. The radionuclide was generated in a cyclotron according to the reaction
nat
Gd(α,x)
155
Dy⟶
155
Tb. The complex was characterized by thin layer chromatography. The
in vitro
stability was assessed in saline and in the presence of bovine serum. The complex showed a satisfactory stability under these conditions for 24 h.
The high catalytic activity of arenediazonium, along with the ability of gold ions to form specific bonds with amikacin, has been used in the fabrication of an electrochemical sensor based on a ...glassy carbon electrode modified with a gold solution and arenediazonium tosylate (
Ar/GGCE
) for the detection and quantification of amikacin upon its release from implants. Atomic force microscopy, cyclic voltammetry, and square-wave voltammetry were used to demonstrate that the use of a gold solution and arenediazonium tosylate for the surface modification of a glassy carbon electrode significantly enhances the electrode characteristics. The determination of amikacin was achieved using square wave voltammetry, which enabled the detection of amikacin at the Ar/GGCE in the concentration range 0.2–60 μM and ensured a limit of detection of 0.058 μM for amikacin released from implants.
Ample experimental evidence indicates that intracerebral injection or infusion of amyloid-beta peptides (Aβ) to rodents induces learning and memory impairments as well as neurodegeneration in brain ...areas related to cognitive function. In the present study, we assessed the effects of a single intracerebroventricular (i.c.v.) injection of aggregated Aβ fragment (25–35) at a dose of 15
nmol/rat on short-term and long-term memory in rats during the 6-month post-surgery period. The results demonstrate that Aβ(25–35)-induced memory impairments in spontaneous alternation behavior in a Y-maze at 17, 36, and 180 days after the surgery as well as in a social recognition task 110 days post-surgery. Aβ(25–35) also impaired spatial memory in an 8-arm radial maze, but did not influence performance of the step-down passive avoidance task. These results suggest that Aβ(25–35) preferably induces impairments of spatial and non-spatial short-term (working) memory rather than long-term memory in rats.
Abstract
The purpose of the research is to study the effect of microbiological preparations on the quality of winter wheat in the northern forest-steppe zone of the Tyumen region. The article ...provides the study of the following microbiological preparations: “Double roots” (Healthy roots)” “Organic”, as well as their combined use. The largest increase in the thousand kernel weight was noted in option 1 “Double roots” (Healthy roots)” and in option 3 “Double roots (Healthy roots) + Organic” by 4.2-2.5 g, which was 7.8-13.3% from the control variant. The highest protein content in winter wheat grain was found in option 1 “Double roots” (Healthy roots) – 13.3%. The rest of the studied options of the experiment were almost at the control level – 12.6-12.7%. According to the grain vitreousness indicator, option 1 “Double roots” (Healthy roots) and option 2 “Organic” dominated – 75 and 72%, respectively. All the studied options exceeded the control in the amount of gluten by 1-4%. The highest amount of gluten in our experiment was noted in option 2 “Organic” – 28.0% and in the first option “Double roots” (Healthy roots)” - 27.0%. According to the gluten quality in the units of the gluten deformation index, 1 quality group is marked – good. Microbiological preparations in the conditions of the northern forest-steppe of the Tyumen region showed a positive effect on improving the quality of winter wheat grain. Grain quality indicators were steadily formed within the standards for food grains of 2-3 classes.
Rodent models of deprivation of parental care are increasingly used to model depression-like disorders induced by early stress. The present study used a model of the consequences of mothers and ...offspring being kept in conditions of nesting material deficiency (NMD) for a prolonged period in early postnatal ontogeny in rats. The aim of this study was to determine whether the behavior of male rats exposed to stress due to being kept in conditions of NMD in the early postnatal period changes and whether any such changes are associated with impairments to the animals’ stress reactivity. Keeping of rats in conditions of NMD from postnatal day 2 to postnatal day 9 did not lead to any significant changes in measures of behavior pointing to anxiety and depressivity recorded in standard tests (open field test, elevated plus maze, sucrose solution preference) either in adolescence or adulthood. NMD in the early postnatal period produced an increase in social attachment (extent of socially oriented behavior manifest as the desire to spend more time in the presence of an unfamiliar individual in a novel context) in one-month-old but not adult animals. Keeping in conditions of NMD improved spatial learning but had no effect on long-term memory in adult rats on assessment of the ability of adults to learn to solve a spatial task in the Barnes maze. Changes in stress reactivity in animals (dynamics of release of corticosterone into the blood) were most marked in adult rats. Thus, NMD in the early postnatal period did not induce anxiety or depression-like behavior in male rats at ages 1 or 6 months but had transient effects on social attachment in young animals and altered stress reactivity on short-term exposure to a moderate stressor (restraint).
An analysis of the use of α-particle beams for the production of radionuclides is carried out. The advantages and disadvantages of this approach in comparison with traditional proton and deuteron ...beams are considered. It is shown that in some cases accelerated helium-ion beams are the only way to produce important medical radionuclides, and in some cases they are competitive with hydrogen-ion beams.
PDF
