380 research outputs found
Radiobiological response of U251MG, CHO-K1 and V79 cell lines to accelerator-based boron neutron capture therapy
In the current article, we provide in vitro efficacy evaluation of a unique accelerator-based neutron source, constructed at the Budker Institute of Nuclear Physics (Novosibirsk, Russian Federation), for boron neutron capture therapy (BNCT), which is particularly effective in the case of invasive cancers. U251MG, CHO-K1 and V79 cells were incubated and irradiated in various concentrations of boric acid with epithermal neutrons for 2–3 h in a plexiglass phantom, using 2.0 MeV proton energy and 1.5–3.0 mA proton current, resulting in a neutron fluence of 2.16 × 1012 cm−2. The survival curves of cells loaded with boron were normalized to those irradiated without boron (to exclude the influence of the fast neutron and gamma dose components) and fit to the linear–quadratic (LQ) model. Colony formation assays showed the following cell survival rates (means ± SDs): CHO-K1: 0.348 ± 0.069 (10 ppm), 0.058 ± 0.017 (20 ppm), 0.018 ± 0.005 (40 ppm); V79: 0.476 ± 0.160 (10 ppm), 0.346 ± 0.053 (20 ppm), 0.078 ± 0.015 (40 ppm); and U251MG: 0.311 ± 0.061 (10 ppm), 0.131 ± 0.022 (20 ppm), 0.020 ± 0.010 (40 ppm). The difference between treated cells and controls was significant in all cases (P < 0.01) and confirmed that the neutron source and irradiation regimen were sufficient for control over cell colony formation. We believe our study will serve as a model for ongoing in vitro experiments on neutron capture therapy to advance in this area for further development of accelerator-based BNCT into the clinical phase
Analysis of the magnetocaloric effect in Heusler alloys: Study of Ni50CoMn36Sn13 by calorimetric techniques
Direct determinations of the isothermal entropy increment, -¿ST , in the Heusler alloy Ni50CoMn36Sn13 on demagnetization gave positive values, corresponding to a normal magnetocaloric effect. These values contradict the results derived from heat-capacity measurements and also previous results obtained from magnetization measurements, which indicated an inverse magnetocaloric effect, but showing different values depending on the technique employed. The puzzle is solved, and the apparent incompatibilities are quantitatively explained considering the hysteresis, the width of the martensitic transition and the detailed protocol followed to obtain each datum. The results show that these factors should be analyzed in detail when dealing with Heusler alloys
Theoretical Modelling of Thermoelectric Properties of Fe2Ti1-xVxSn Heusler Alloys
Fe2TiSn is a full-Heusler alloy with 24 valence electrons per formula unit. Its electronic
properties, thermal and chemical stability, relatively low cost of constituent elements make it a
potential thermoelectric material for practical applications for conversion of waste heat to
electricity
Rhodiola rosea L.:from golden root to green cell factories
Rhodiola rosea L. is a worldwide popular plant with adaptogenic activities that have been and currently are exploited in the traditional medicine of many countries, as well as, examined in a number of clinical trials. More than 140 chemical structures have been identified which belong to several natural product classes, including phenylpropanoid glycosides, phenylethanoids, flavonoids and essential oils, and are mainly stored in the rhizomes and the roots of the plant. A number of mechanisms contribute to the adaptogenic activities of R. rosea preparations and its phytochemical constituents. Among them, the intrinsic inducible mammalian stress responses and their effector proteins, such as heat shock protein 70 (Hsp70), are the most prominent. Due to its popular medicinal use, which has led to depletion of its natural habitats, R. rosea is now considered as endangered in most parts of the world. Conservation, cultivation and micropropagation are all implemented as potential preservation strategies. A number of in vitro systems of R. rosea are being developed as sources of pharmaceutically valuable secondary metabolites. These are greatly facilitated by advances in elucidation of the biosynthetic pathways and the enzymes, which catalyse the production of these secondary metabolites in the plant. In addition, biotechnological approaches show promise towards achieving sustainable production of R. rosea secondary metabolites.</p
СЛУЧАЙ ДИРОФИЛЯРИОЗА РАЗГИБАТЕЛЯ ПАЛЬЦЕВ КИСТИ, ИМИТИРУЮЩИЙ СУХОЖИЛЬНЫЙ ГАНГЛИЙ
Early diagnostics for parasitic diseases of musculoskeletal system is rather challenging due to rare occurrence of described pathology.The authors review a clinical case of a female patient, 49 years old, with dirofilariasis of tendinous sheath of extensor pollicis longus. The patient was admitted to hospital with a diagnosis of dorsal hand ganglion cyst. Correct diagnosis was made only after parasite extraction during surgical procedure. The authors discuss issues of differential diagnosis of such disease as well as dorsal hand ganglion. Diagnosis can be confirmed by preoperative ultrasound scans of hand soft tissues.Своевременная диагностика паразитарных заболеваний опорно-двигательного аппарата представляет определенные сложности, обусловленные редкостью данной патологии. В статье представлено клиническое наблюдение – случай дирофиляриоза влагалища разгибателя пальца кисти у 49-летней женщины, госпитализированной с диагнозом «гигрома тыльной поверхности кисти». правильный диагноз заболевания был поставлен только после извлечения паразита во время операции. Обсуждены проблемы дифференциальной диагностики данного заболевания и гигромы тыла кисти. Для уточнения диагноза предложено использовать предоперационное узИ мягких тканей кисти
Accelerator-based boron neutron capture therapy for malignant glioma: a pilot neutron irradiation study using boron phenylalanine, sodium borocaptate and liposomal borocaptate with a heterotopic U87 glioblastoma model in SCID mice
Purpose: To evaluate the efficacy of boron neutron capture therapy (BNCT) for a heterotopic U87 glioblastoma model in SCID mice using boron phenylalanine (BPA), sodium borocaptate (BSH) and liposomal BSH as boron compounds at a unique, accelerator-based neutron source.
Materials and methods: Glioblastoma models were obtained by subcutaneous implantation of U87 cells in the right thighs of SCID mice before administration of 350 mg/kg of BPA (BPA-group), 100 mg/kg of BSH (BSH-group) or 100 mg/kg of BSH in PEGylated liposomes (liposomal BSH-group) into the retroorbital sinus. Liposomes were prepared by reverse-phase evaporation. Neutron irradiation was carried out at a proton accelerator with a lithium target developed for BNCT at the Budker Institute of Nuclear Physics, Novosibirsk, Russian Federation. A proton beam current integral of 3 mA/h and energy of 2.05 MeV were used for neutron generation.
Results: Boron compound accumulation in tumor tissues at the beginning of irradiation was higher in the BPA group, followed by the Liposomal BSH and BSH groups. Tumor growth was significantly slower in all irradiated mice from the 7th day after BNCT compared to untreated controls (p < .05). Tumor growth in all treated groups showed no large variation, apart from the Irradiation only group and the BPA group on the 7th day after BNCT. The overall trend of tumor growth was clear and the differences between treatment groups became significant from the 50th day after BNCT. Tumor growth was significantly slower in the Liposomal BSH group compared to the Irradiation only group on the 50th (p = .012), 53rd (p = .005), and the 57th (p = .021) days after treatment. Tumor growth in the Liposomal BSH group was significantly different from that in the BPA group on the 53rd day after BNCT (p = .021) and in the BSH group on the 50th (p = .024), 53rd (p = .015), and 57th (p = .038) days after BNCT. Skin reactions in the form of erosions and ulcers in the tumor area developed in treated as well as untreated animals with further formation of fistulas and necrotic decay cavities in most irradiated mice.
Conclusions: We observed a tendency of BNCT at the accelerator-based neutron source to reduce or suspend the growth of human glioblastoma in immunodeficient animals. Liposomal BSH showed better long-term results compared to BPA and non-liposomal BSH. Further modifications in liposomal boron delivery are being studied to improve treatment outcomes.journal articl
Extremely polysubstituted magnetic material based on magnetoplumbite with a hexagonal structure: Synthesis, structure, properties, prospects
Crystalline high-entropy single-phase products with a magnetoplumbite structure with grains in the µm range were obtained using solid-state sintering. The synthesis temperature was up to 1400 °C. The morphology, chemical composition, crystal structure, magnetic, and electrodynamic properties were studied and compared with pure barium hexaferrite BaFe 12 O 19 matrix. The polysubstituted high-entropy single-phase product contains five doping elements at a high concentration level. According to the EDX data, the new compound has a formula of Ba(Fe6Ga1.25In1.17Ti1.21Cr1.22Co1.15)O19. The calculated cell parameter values were a = 5.9253(5) Å, c = 23.5257(22) Å, and V = 715.32(9) Å3. The increase in the unit cell for the substituted sample was expected due to the different ionic radius of Ti/In/Ga/Cr/Co compared with Fe3+. The electrodynamicmeasurements were performed. The dielectric and magnetic permeabilities were stable in the frequency range from 2 to 12 GHz. In this frequency range, the dielectric and magnetic losses were??0.2/0.2. Due to these electrodynamic parameters, this material can be used in the design of microwave strip devices. © 2019 by the authors. Licensee MDPI, Basel, Switzerland.Funding: The work was supported by the Russian Science Foundation, project No. 18-73-10049
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