Contemporary Approach with Mitral Valve Allograft in the Treatment of Tricuspid Valve Pathology

Symptomatic tricuspid valve diseases are associated with a high risk of heart failure and poor prognosis. The current valve substitutes still carry the risk of associated complications. Allografts have been considered a valuable surgical option for decades since the first reports were introduced. The challenging surgical technique along with controversial results and homograft shortage discourage surgical society from wider use of allografts in tricuspid surgery. The largest world surgical experience with mitral allograft in the treatment of tricuspid valve disease is described in the study. A total of 20 patients underwent tricuspid valve replacement by mitral homograft in two clinics from October 2021 to February 2023. Surgical technique and initial results are presented in the chapter. There was no early mortality, postoperative bleeding, myocardium infarction, stroke, or sternal wound infection. Two patients needed permanent pacemaker implantation after redoing surgery before discharge. In the follow-up period, two patients suffered from a relapse of infective endocarditis in 3 and 6 months postoperatively with moderate homograft dysfunction, none of them underwent reintervention. There was no late mortality or permanent pacemaker implantation in the follow-up period. Satisfactory clinical and hemodynamic results, reproduceable technique and accessibility make homografts plausible valve substitutes in tricuspid surgery

Radionuclide Analysis on Bamboos following the Fukushima Nuclear Accident

In response to contamination from the recent Fukushima nuclear accident, we conducted radionuclide analysis on bamboos sampled from six sites within a 25 to 980 km radius of the Fukushima Daiichi nuclear power plant. Maximum activity concentrations of radiocesium 134Cs and 137Cs in samples from Fukushima city, 65 km away from the Fukushima Daiichi plant, were in excess of 71 and 79 kBq/kg, dry weight (DW), respectively. In Kashiwa city, 195 km away from the Fukushima Daiichi, the sample concentrations were in excess of 3.4 and 4.3 kBq/kg DW, respectively. In Toyohashi city, 440 km away from the Fukushima Daiichi, the concentrations were below the measurable limits of up to 4.5 Bq/kg DW. In the radiocesium contaminated samples, the radiocesium activity was higher in mature and fallen leaves than in young leaves, branches and culms

Radionuclide speciation in sediments of the Yenisei River

The examination of sediment samples collected from the Yenisei River revealed the presence of artificial radionuclides characteristic of radioactive discharges from the MCC facility: isotopes of europium (152Eu, 154Eu, and 155Eu), cesium (137Cs and 134Cs), 60Co,90Sr, and transuranium elements. Radionuclide concentrations in sediment layers remained high as far as 240 km downstream of the MCC. The vertical distribution of radionuclides in sediment cores was very complex, and down-core variations were due to different amounts of radionuclides released by the MCC and due to variations in the hydrologic conditions in the river. Sequential extraction performed on samples of the upper layers of the sediment core showed different degrees of potential environmental availability of artificial radionuclides: the amounts of extracted 90Sr, 152Eu and 241Am were the largest (60–80% of initial activity), then followed 60Co (30%), 238,239,240Pu (15–30%), and, last, 137Cs (5–15%). The distribution of 238U among chemical fractions of sediments was similar to that of 60Co and 238,239,240Pu: 30–40% of 238U initial activity was extracted. In a few samples, 241Am was present in the unextractable form, which may be accounted for by the presence of microparticles of the reactor fuel

Accumulation of

The study investigates accumulation of radionuclides in 5 species of berry shrubs in forests of the Yenisei River basin (the Krasnoyarskii Krai, Russia). Activity concentrations of 60Co, 90Sr, 137Cs, 238U and transuranic elements in aboveground organs of the shrubs have been determined and their transfer factors calculated. Analysis of the calculated TFs shows that shrubs concentrate 90Sr more effectively than other study elements (TF = 0.25–1.9). The highest concentration of 137Cs is recorded in the berries and leaves of Ribes nigrumand Rubus idaeus. For these species, the range of 137Cs TFs (0.006–0.027) overlaps with the range of 238U TFs (0.004-0.018). For the aboveground parts of Ribes nigrum, TFs for transuranic radionuclides (0.01–0.056) are similar to or higher than the TFs for 238U and 137Cs

Bioavailability of

The experiments on accumulation of 99Tc by Elodea biomass showed that 99Tc activity concentration can reach 120 ± 6 Bq/g, with the concentration factor for 99Tc 2700 ± 500 L/kg. In experiments on 99Tc release, over 504 h about 82% of the total 99Tc activity was released into the water from plant biomass; most of 99Tc was released within the first 192 h. Results of chemical fractionation of the biomass show that 99Tc contained in biomass was mainly concentrated in the exchangeable and the adsorbed fractions (83%). Thus, the data obtained using chemical fractionation of biomass confirmed the experimental data on 99Tc release, which suggested that most of the biomass-bound 99Tc was adsorbed on the biomass surface. 99Tc tightly bound to Elodea biomass (fractions of organics and mineral residue) constituted just 17% of the total 99Tc activity. Decreased illumination of Elodea shoots during the experiment did not cause any reduction in 99Tc activity concentration or concentration factor. Results of chemical fractionation of the biomass grown under lower illumination conditions show that the percentage of 99Tc tightly bound to Elodea biomass (fractions of organics and mineral residue) decreased while the 99Tc of the adsorbed fractions decreased. Our results and data reported by other authors suggest that some part of 99Tc activity can be bioavailable to living organisms and that the portion of bioavailable 99Tc can be determined by a number of factors

Artificial radionuclides in fish fauna of the Yenisei River in the vicinity of the Mining-and-Chemical Combine (Siberia, Russia)

Activities of radionuclides were measured in five species of fish (grayling, dace, crucian carp, pike, cod) sampled in the Yenisei River (Siberia, Russia) in the vicinity of the Mining-and-Chemical Combine (ROSATOM) from 2007 to 2010, with a gamma-spectrometer (Canberra, USA). The analyses of samples of organs and tissues of fish species revealed artificial (46Sc, 51Cr, 54Mn, 58,60Co, 59Fe, 65Zn, 85Sr, 99Mo, 103,106Ru, 137Cs, 141,144Ce) and natural (7Be, 40K) radionuclides in fish organs and tissues, including edible ones. The major percent (up to 80%) of 137Cs and 40K activity occurred in muscles of fish species, which also contained considerable percentages of 60Co (up to 70%) and 65Zn (up to 20%). Seasonal changes in the intake of artificial radionuclides by zoobenthos-feeding fish species (grayling and dace) were recorded and they were followed by an activity concentration increase in internal organs. The dramatic increase in radionuclide intake by grayling coincided with the change of diet source. Hence, the feeding behavior of fish can change the fluxes of artificial radionuclides in the Yenisei River. The most effective diet transfer of a radionuclide from gammarus to grayling (muscles and total body) was recorded for 40K (1.3) and much less effective for artificial nuclides

Accumulation of artificial radionuclides by edible wild mushrooms and berries in the forests of the central part of the Krasnoyarskii Krai

The study addresses accumulation of radionuclides by mushrooms and berry shrubs from the forest soil in the 30-km area around the MCC (the Krasnoyarskii Krai, Russia). The Suillus granulatus and S. luteus mushrooms have been found to be the best bioindicators in this area. The level of 137Cs concentration in these species can reach 10 kBq/kg dry mass. The 137Cs transfer factor (TF) by the mushrooms varies 5-fold among the sites that receive radionuclides from different sources. The level of radionuclide activities accumulated by berry shrubs is 2–3 orders of magnitude lower than the activities accumulated by mushrooms. No relationship has been found between the TFs of radionuclides to the shrubs and the pathway via which the radionuclides enter the soil. The contribution of the dose due to intake of mushrooms and berries to the annual effective dose of internal exposure to residents does not exceed 150 μSv/year and 1.4 μSv/year, respectively, estimated from the registered levels of accumulated 137Cs

Transonic Wing Design Using Inverse and Optimization Methods

Presented is an effective procedure for aerodynamic design of transonic wings, based on joint use of fast method for direct calculation and inverse and numerical optimization methods developed by the authors. Each component of the procedure developed is described. Some examples of designing sophisticated advanced configurations are given