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.
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The excitation functions of nuclear reactions natBa(α,xn)132, 133m, 134, 135, 137m,g, 139, 141Ce, natBa(α,x)135, 140La and natBa(α,x)131, 133m, 135mBa were measured for the first time in the energy ...range of 60 → 20 MeV using stack foil technique combined with γ-ray spectrometry. A comparative analysis of the experimental results with TENDL-2021 data was carried out. The thick target yields of radioisotopes Ba, La, and Ce were calculated by integrating the values of the cross sections. The feasibility of practical use of the studied reactions for the production of medical radioisotopes 134Ce and 135La is discussed.
The cross sections for the formation of 160Er, 161Er, 162mHo, 157Dy in nuclear reactions natDy(α,x) in the energy range 53 → 20 MeV were measured by the stacked foils method. Most of the data were ...obtained for the first time. A comparison of the data with simulation results from the TENDL-2019 library is given. The 161Er yield on a thick target is 88.4 MBq/µAh. The natDy(α,x)161Er → 161Ho route was studied for 161Ho production. The possibility to produce 161Ho in an amount sufficient for medical applications was shown. The main radioisotope impurity is 160m,gHo (in the amount of 3–6% in terms of activity). The thick target yield of 160Er is 2.16 MBq/µAh, which is significantly less than those of the reactions induced by protons and deuterons.
The cross sections for nuclear reactions natEr(α,x) were measured in the energy range 60 → 10 MeV using the stacked-foil technique. The experiments were carried out in a wider energy range in ...comparison with previous works. The results are consistent with other studies and modeling using TENDL-2019. The 167Tm yield was 5.4 MBq/μAh in the range 60 → 30 MeV, and the main long-lived impurity is 168Tm (0.78% in terms of activity). The 165Tm yield is 4.6 MBq/μAh (60 → 40 MeV). 169Yb is formed with a yield of 1.0 MBq/μAh in the energy range 60 → 20 MeV.
•Activation cross-sections of alpha-particle induced reactions were measured on natural erbium target.•Stacked-foil technique, activation method and gamma-spectroscopy were used.•Cross section for ytterbium (167,169Yb and thulium (165Tm, 166Tm, 167cumTm, 168Tm) were determined.•Production routs of 169Yb, 167Tm and 165Er were discussed.
The production cross sections of
163,165,166,167,168
Tm in alpha-particle induced reactions on
165
Ho were measured in 27–60 MeV energy range using the stacked-foil activation technique. The thick ...target yield of the medical isotope
167
Tm is 2.22 MBq/µAh. The radioisotope
165
Tm that can be used in the generator system to obtain
165
Er is also produced. The measured excitation functions were compared with the data from TENDL-2019 and TENDL-2021 libraries and the previous experimental values. Various methods of
165
Tm and
165
Er production were compared. The reaction
165
Ho(α,4n)
165
Tm →
165
Er was considered as a potential method for the production of
165
Er.
A deterministic theory describing the behavior of an ultrathin lubricant film between two atomically smooth solid surfaces is proposed. For the description of lubricant state the parameter of excess ...volume arising due to chaotization of solid medium structure in the course of melting is introduced. Thermodynamic and shear melting are described. Dependences of friction force on temperature of lubricant, shear velocity of rubbing surfaces, and pressure upon surfaces are analyzed. Within the framework of a simple tribological model the stick–slip mode of friction, when the lubricant periodically melts and solidifies, is described. The obtained results are qualitatively compared with the experimental data.
► This paper presents a new approach in finding a solution to the ultrathin lubricant film problem. ► The proposed procedure is based on the concept of phase transition. ► Our theory is deterministic. Thermodynamic and shear melting are described consistently. ► The basic aim of this work is to calculate dependences of friction force on temperature of lubricant, shear velocity of rubbing surfaces, and pressure upon surfaces.
Rapid rehabilitation and restoration of the function of damaged anatomical areas in the military is the main goal of military medicine. In the case of gunshot wounds of the knee joint with defects of ...soft tissues, one of the optional methods of reconstructive and plastic "closure" is the usage of a propeller flap. The clinical case represents a mine-explosive wound of the lower extremities with a defect of the soft tissues of the lateral aspect of the right knee joint in a serviceman of the Ukrainian Armed Forces as a result of artillery shelling in the east of Ukraine in November 2022. There was an isolated shrapnel tangential non-penetrating wound on the lateral aspect of the right knee joint with a soft tissue defect measuring 7.2x3.2-1.0 cm. The aim of the work was to study the thermographic and sonographic features of soft tissue perfusion after gunshot injuries of the lower extremities and on the basis of the temperature dynamics data from the wound surface in combination with the sonographic examination of the vessels to determine the rationality and relevance in the reconstruction of defects of the lower extremities by propeller tactics. Reconstruction with flap with a perforating vessel as the "key" of LSGA (lateral superior genicular artery) and a dynamic multimodal concept (DMT) with the use of audio doppler in the pre-, intra- and postoperative period) with closure of the defect due to a rotary perforating flap with supplying was carried out. During the entire period of treatment, of the injured the temperature background from the surface of the flap was followed up using FLIR C2, and sonographic changes in blood flow were monitored in the projection of the LSGA location. We came to the conclusion that applying the technique of flaps on perforating vessels, several goals are tactically achieved: restoration of the completeness and function of the damaged area, reduction of complications in the recipient and donor areas. Thus, the propeller flap can be classified as a primary option for "replacemen t" of tissues among the restorative tactics of the damaged area of the lower extremities caused by a gunshot origin.
Purpose. Development of a method for forming an optimal portfolio of venture projects taking into account risks, uncertainty in initial data and limited financial resources. Methodology. To calculate ...the accuracy of forecasting prices, which are necessary for calculating the parameters of the stochastic optimization model for the formation of a portfolio of projects, we used the theory of random variables and regression analysis. The problem of choosing the optimal portfolio of venture projects was solved using stochastic mathematical programming. Findings. A model for creating an optimal portfolio of venture projects has been developed. It is a stochastic mathematical programming model that can be used to solve problems of investing in venture projects in the extractive industry. This model takes into account the risks associated with obtaining the expected income from the implementation of each venture project, the uncertainty in the initial data for calculating the income from the projects selected in the portfolio, as well as the limited funds required to finance the project portfolio. Originality. The stochastic optimization model for the formation of an optimal portfolio of projects, taking into account the peculiarities of venture projects, in particular, their high riskiness, has been significantly improved and adapted. Practical value. The proposed model for the formation of an optimal portfolio of venture projects can be used at mining enterprises, whose development strategy involves the implementation of innovative, high-risk projects. The use of this model in strategic planning will allow an enterprise to receive the maximum income from venture projects in the face of a lack of financial resources, as well as instability of the innovation market.
The present work describes the physico-chemical, sanitary and microbiological properties of the peloid and feeding waters of Lake Utinoye (Kamchatka), investigated over 50 years of operation of the ...mud deposit "Lake Utinoye". An increasing presence of thermomineral waters of the Paratunsky hydrothermal deposit in the composition of the feeding waters of the lake has been established. The content of microelement components in the surface waters and in the ecological structure of the peloid is determined. It discovers the ratio of micronutrient concentrations in the ecological structure of the peloid, the accumulation of toxic substances in the solid phase of the peloid. The degree of non-compliance of peloids with medical conditions is established, the description of the method of substandard medical mud activation and its comparison with the efficiency of passive regeneration are given. The structure of a specific microbial community involved in the formation of therapeutic mud is determined. The action mechanisms of thermal water chemical factors at the level of microelements on the community of bottom microorganisms of therapeutic mud have been established. The paper describes the physicochemical, biochemical and microbiological mechanisms of peloid regeneration. The dynamics of sanitary and bacteriological parameters of therapeutic mud in the process of their regeneration in the mud storage is established. The level of the most important manifestations of the peloid biological activity based on the dynamics of the survival of the potentially pathogenic flora in the activation of therapeutic mud has been established.
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