116 research outputs found
Breit and QED effects on the 3d9 D3/2 2 →2D5/2 transition energy in Co-like ions
No full textThe multiconfiguration Dirac-Hartree-Fock theory is used to calculate the 3d9D3/22→2D5/2 transition energy for Co-like ions with Z=28-100. We investigate how electron correlation, frequency-independent and -dependent Breit interactions, as well as QED corrections vary along the sequence. The well-understood frequency-independent Breit contribution has the largest contribution for all ions. Among the corrections to this, correlation decreases rapidly with Z, the frequency-dependent Breit contribution is important especially for high-Z ions, and the self-energy contribution to the QED becomes the largest correction already for Z>50. We evaluate and compare results for the Self-energy in three different approximations, (i) the approach implemented in the grasp2k package, (ii) the method based on Welton's concept and (iii) a model operator approach recently developed by Shabaev and coworkers. Through comparison with experimental values, it seems that the third set of results have the best agreement with experiments, but the difference from experiments for high-Z ions, is around 0.03%-0.04%, and therefore our results are outside the error bars of the experiments
Predictors of adverse events in the mid-term postoperative period in patients who underwent carotid endarterectomy
No full text<p><strong>Aim.</strong> Emphasis in the study was placed on the identification of unfavorable prognosis factors associated with carotid endarterectomy (CEE) during mid-term follow-up.<br /><strong>Methods.</strong> Over a period from 2015 to 2016, 222 CEE operations were performed. Most patients (n = 190; 85.5%) underwent CEE using a patch of xenopericardium, 14.4% (n = 32) received eversion CEE, and a temporary shunt was used in 14.4% (n = 32). Hybrid revascularization in the volume of percutaneous coronary intervention (PCI) + CEE was performed in 9.9% (n = 22) patients. The groups under study were compared by using a chi-square test followed by subsequent analysis of the shares, or if ordinal characters or quantitative traits with a distribution different from the normal one occurred—by using a Mann – Whitney U-test. Correction of multiple comparisons was done by calculating an average fraction of false discoveries of the hypotheses (false discovery rate). The analysis of prognostic factors was done using the odds ratio (OR) by means of the 2 × 2 tables.<br /><strong>Results.</strong> Among the complications detected in the mid-term follow-up, the most common adverse event was the development of MI in 3.6% (n = 8) of patients. According to color duplex scanning of brachiocephalic arteries, restenosis of the operated ICA was observed in 4.5% of patients. The following risk factors significantly increased the risk of adverse events: angina pectoris II–III functional class (OR = 3.84%, CI = 1.24–11.9), SYNTAX Score &gt;22 (OR = 2.83, CI = 1.137–7.086).<br /><strong>Conclusion.</strong> Based on the results of a single-center prospective retrospective study, significant risk factors for adverse outcome in the mid-term postoperative period were identified.</p><p>Received 10 May 2017. Revised 27 September 2017. Accepted 5 October 2017.</p><p><strong>Funding:</strong> The research was done with support of the grant (No. 12090ГУ/2017) awarded by the Fund for Facilitation of Innovations within the framework of the “Umnik-2016” project (Kemerovo).</p><p><strong>Conflict of interest:</strong> The authors declare no conflict of interest.</p><p><strong>Author contributions</strong><br />Conception and study design: R.S. Tarasov, A.I. Anufriyev <br />Data collection and analysis: A.R. Shabaev<br />Drafting the article: A.N. Kazantsev, N.N. Burkov <br />Critical revision of the article: A.V. Mironov<br />Final approval of the version to be published: L.S. Barbarash</p></jats:p
Electron-impact excitation of neutral boron using the R-matrix with pseudostates method
No full textWe have carried out a large R-matrix with pseudostates (RMPS) calculation of the electron-impact excitation of neutral boron. The RMPS method has been employed for the excitation/ionisation of many light fusion related species, but primarily for one or two active electrons. The present 640-term close-coupling calculation included three distinct pseudostate expansions. This enabled us to converge both the N-electron structure for three active open-shell electrons and accurately represent the high Rydberg and target continuum states. The derived Maxwell-averaged effective collision strengths will be employed to model the spectral emission from boron, which is of importance to both current (TEXTOR)and future (ITER) magnetic fusion reactors. The full set of effective collision strengths is available at the Oak Ridge National Laboratory Controlled Fusion
Atomic Data Center Web site.</p
Testing quantum electrodynamics in extreme fields using helium-like uranium
No full textFunding Information: The results presented here are based on the experiment E125, which is performed at the infrastructure ESR at the GSI Helmholtzzentrum für Schwerionenforschung, Darmstadt, in the framework of FAIR Phase-0 and SPARC collaboration. This work is supported by the Horizon 2020 research and innovation programme of the European Union and grant agreement no. 6544002. We acknowledge the support provided by ErUM FSP T05-‘Aufbau von APPA bei FAIR’ (BMBF nos. 05P19SJFAA and 05P21SJFA1). We thank A. Malyshev, V. Shabaev and Y. Kozhedub for providing previously unknown theoretical results and also for the discussions on theoretical uncertainties. M.T. thanks the ExtreMe Matter Institute EMMI and Alexander von Humboldt Foundation for their support for the stays at the GSI for the preparation and data acquisition. L.D. acknowledges funding support from the Initiative Physique des Infinis (IPI), a research training programme of the Idex SUPER at Sorbonne Université. Funding Information: The results presented here are based on the experiment E125, which is performed at the infrastructure ESR at the GSI Helmholtzzentrum für Schwerionenforschung, Darmstadt, in the framework of FAIR Phase-0 and SPARC collaboration. This work is supported by the Horizon 2020 research and innovation programme of the European Union and grant agreement no. 6544002. We acknowledge the support provided by ErUM FSP T05-‘Aufbau von APPA bei FAIR’ (BMBF nos. 05P19SJFAA and 05P21SJFA1). We thank A. Malyshev, V. Shabaev and Y. Kozhedub for providing previously unknown theoretical results and also for the discussions on theoretical uncertainties. M.T. thanks the ExtreMe Matter Institute EMMI and Alexander von Humboldt Foundation for their support for the stays at the GSI for the preparation and data acquisition. L.D. acknowledges funding support from the Initiative Physique des Infinis (IPI), a research training programme of the Idex SUPER at Sorbonne Université. Publisher Copyright: © 2024, The Author(s).Quantum electrodynamics (QED), the quantum field theory that describes the interaction between light and matter, is commonly regarded as the best-tested quantum theory in modern physics. However, this claim is mostly based on extremely precise studies performed in the domain of relatively low field strengths and light atoms and ions 1–6. In the realm of very strong electromagnetic fields such as in the heaviest highly charged ions (with nuclear charge Z ≫ 1), QED calculations enter a qualitatively different, non-perturbative regime. Yet, the corresponding experimental studies are very challenging, and theoretical predictions are only partially tested. Here we present an experiment sensitive to higher-order QED effects and electron–electron interactions in the high-Z regime. This is achieved by using a multi-reference method based on Doppler-tuned X-ray emission from stored relativistic uranium ions with different charge states. The energy of the 1s 1/22p 3/2 J = 2 → 1s 1/22s 1/2 J = 1 intrashell transition in the heaviest two-electron ion (U90+) is obtained with an accuracy of 37 ppm. Furthermore, a comparison of uranium ions with different numbers of bound electrons enables us to disentangle and to test separately the one-electron higher-order QED effects and the bound electron–electron interaction terms without the uncertainty related to the nuclear radius. Moreover, our experimental result can discriminate between several state-of-the-art theoretical approaches and provides an important benchmark for calculations in the strong-field domain.publishersversionpublishe
Reconstructive surgery in the complex treatment of breast cancer (10 years of experience)
No full textThe aim of the study is to improve the quality of life of women with breast cancer (BC) and a high risk of its development by performing one-stage or delayed reconstruction of the lost breast.The objectives of the study were: to clarify the criteria for selecting patients for prophylactic mastectomy; development of surgical tactics in the treatment of breast cancer and a high risk of its development; assessment of oncological safety of LME; clarification of the methods of reconstruction of the breast; analysis of postoperative complications, including the effect of neoadjuvant PCT during simultaneous breast reconstruction on their frequency, and determination of possible ways to prevent them.Material and methods. The prospective controlled study included 258 patients who underwent surgical treatment in our department between 2007 and 2016. The criteria for the inclusion of patients in the study were: carrying out radical surgical treatment for breast cancer, both in isolation and in combination with the reconstruction of the lost breast; carriage of germline mutations in the tumor suppressor genes BRCA1 and BRCA2, the presence of first-degree relatives suffering from breast cancer, previous BRCA-associated breast cancer; the desire of patients with multiple recurrent proliferative benign breast diseases that are not amenable to conservative and surgical treatment to use the surgical method of breast cancer prophylaxis with immediate restoration of the breast.Results. According to the Beck Depression Questionnaire, 72 % of patients in the first group of patients had a critical and high level of depression, while patients who underwent CME with one-stage reconstruction did not have such levels of depression. At the same time, a relatively favorable psychological state of patients with a low level of depression was observed in 17 of 21 patients in the RME + delayed reconstruction group (which amounted to 81% of the group), in 21 of 22 patients in the RME + simultaneous reconstruction group (95% of the group), and only in 5 of 43 patients in the RME group (12% of the group) (χ2 = 51.6; critical value 9.2 at p ≤ 0.01).Conclusions. When analyzing the results obtained, we once again became convinced of the oncological safety of LME with a one-stage reconstruction of the breast, subject to certain requirements. In the presence of appropriate conditions, it is possible to preserve the SAC during the LME. Preventive LME with simultaneous breast reconstruction is the method of choice in patients with a high risk of developing breast cancer, subject to the appropriate selection criteria and the patient's desire
Анализ топографических сценариев формирования очагов кальцификации в дисфункциональных клапанах сердца и атеросклеротических бляшках
No full textAim. To analyze the topographic patterns of valvular and atherosclerotic calcification growth.Methods. Dysfunctional aortic valves (n = 18) and atherosclerotic plaques (n = 20) were fixed in formalin, postfixed in 1% osmium tetroxide, consecutively stained by 2% osmium tetroxide and 2% uranyl acetate, and embedded into epoxy resin (Epon) with the further grinding and polishing ofthe samples. Upon the counterstaining by lead citrate and sputter coating with carbon, samples were visualized by backscattered scanning electron microscopy. Elemental analysis was conducted via energy-dispersive X-ray spectroscopy. Measurement of Ca/P ratio within the mineral deposits was carried out employing a pool table principle (i.e., in the center of the deposit, in the near and far circumferences (clockwise), and in control regions around the mineral deposit). Topographic patterns of calcifications were modeled using the correlation analysis. Results. Significant correlation was revealed between the Ca/P ratio in the deposit center and in the near and far circumferences of deposit in both in valvular (r = 0,35-0,78 - near circumference; r = 0,63-0,69 - far circumference) and atherosclerotic mineral deposits (r = 0,37-0,56 - near circumference; r = 0,48-0,63 - far circumference), suggesting the hierarchical growth of cardiovascular calcification around the initial nucleation sites.Conclusion. Valvular and atherosclerotic calcifications development is concentric.Цель. Проанализировать топографические сценарии формирования кальцифика-тов в дисфункциональных аортальных клапанах сердца и атеросклеротических бляшках.Материалы и методы. Дисфункциональные аортальные клапаны сердца (n = 18) и атеросклеротические бляшки (n = 20) фиксировали в формалине, постфиксировали в 1% тетраоксиде осмия, последовательно окрашивали 2% тетраоксидом осмия и 2% ура-нилацетатом и заключали в эпоксидную смолу Epon с последующей шлифовкой и полировкой сформованных блоков. После контрастирования цитратом свинца и напыления углеродом проводили визуализацию образцов методом сканирующей электронной микроскопии в обратно рассеянных электронах и элементный анализ кальцификатов методом энергодисперсионной рентгеновской спектроскопии. Измерение соотношения Ca/P в кальцификатах аортальных клапанов и бляшек произведено по схеме «бильярдного стола» в центре кальцификата и часовой стрелке в ближней и дальней окружностях, а также в контрольных участках возле и вдали от кальцификата. Топографические сценарии формирования кальцификатов моделировали при помощи корреляционного анализа.Результаты. Выявлена значимая корреляция соотношения Ca/P в центре кальцификата с таковой в ближней и дальней окружностях как в клапанных (г = 0,35-0,78 в ближней окружности; г = 0,63-0,69 в дальней окружности), так и атеросклеротических (г = 0,37-0,56 в ближней окружности; г = 0,48-0,63 в дальней окружности) кальцификатах, что свидетельствует об иерархическом принципе формирования очагов кальцификации.Заключение. Кальцификация в кальцинированных аортальных клапанах сердца и атеросклеротических бляшках развивается по концентрическому принципу (от центра к периферии)
Elemental analysis insights into atherosclerotic calcification
No full textBackground. Atherosclerosis is frequently accompanied by an extensive calcification, yet the mechanisms behind its initiation and progression remain obscure. In particular, there is unclear whether large mineral deposits grow concentrically or by merging of microcalcifications. Aim of the study was to investigate calcium phosphate maturation during atherosclerotic calcification employing an elemental analysis approach. Material and methods. We collected 20 calcified atherosclerotic plaques excised during carotid endarterectomy. After being fixed in formalin and postfixed in osmium tetroxide, plaques were dehydrated and stained in uranyl acetate with the subsequent embedding into epoxy resin, grinding, polishing, and lead citrate counterstaining. Upon the sputter coating with carbon, we visualised the plaque microanatomy by means of backscattered scanning electron microscopy. Elemental analysis was carried out using energy-dispersive X-ray spectroscopy in the backscattered mode at high vacuum and 20 kV voltage. The analysis was performed at 11 radial points within the calcium deposit and 4 control points at ascending distance from the deposit. Results. Calcium to phosphate ratio differed between the calcium deposits in distinct plaques and also within the same plaque. We found a statistically significant correlation between calcium to phosphate ratio in the center and periphery of the calcium deposit. Areas with distinct electron density had different calcium to phosphate ratio; however, there was no clear correlation between these parameters. Conclusion. Correlation of calcium to phosphate ratio in the center and periphery of the calcium deposit suggests that its maturation develops from the center to the periphery rather than by merging of neighboring calcium deposits
Relativistic Stark energies of hydrogen-like ions
No full textThe relativistic energies and widths of hydrogen-like ions exposed to the
uniform electric field are calculated. The calculations are performed for the
ground and lowest excited states using the complex scaling technique in
combination with a finite-basis method. The obtained results are compared with
the non-relativistic values. The role of relativistic effects is investigated.Comment: 21 pages, 5 figure
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