Relativistic calculations of the energies of the low-lying 1sns1sns, 1snp1snp, 1snd1snd states and the probabilities of the one-photon 1snl→1sn′l′1snl\to 1sn'l' transitions in heliumlike uranium

For heliumlike uranium, the energies of the singly-excited $1sns$, $1snp$, and $1snd$ states with $n\leq 4$ and the probabilities of the one-photon $1s3d\to 1s2p$, $1s3p\to 1s2s$, $1s3p\to 1s2p$ and $1s4d\to 1s2p$ transitions are evaluated. The calculations are performed within the Breit approximation using the configuration-interaction method in the basis of the Dirac-Fock-Sturm orbitals. The QED corrections to the energy levels are calculated employing the model-QED-operator approach. The nuclear recoil, frequency-dependent Breit-interaction, nuclear polarization, and nuclear deformation corrections are taken into account as well

Spontaneous vacuum decay in low-energy collisions of heavy nuclei beyond the monopole approximation

The problem of spontaneous vacuum decay in low-energy collisions of heavy nuclei is considered beyond the scope of the monopole approximation. The time-dependent Dirac equation is solved in a rotating coordinate system with $z$-axis directed along the internuclear line and the origin placed at the center of mass. The probabilities of electron-positron pair creation and the positron energy spectra are calculated in the approximation neglecting the rotational coupling. The two-center potential is expanded over spherical harmonics and the convergence with respect to the number of terms in this expansion is studied. The results show that taking into account the two-center potential instead of its spherically symmetric part preserves all the signatures of the transition to the supercritical regime that have been found in the framework of the monopole approximation and even enhances some of them.Comment: 7 pages, 4 figures, 1 tabl

Positron supercritical resonances and spontaneous positron creation in slow collisions of heavy nuclei

We present a theoretical and computational study of positron supercritical resonances in systems consisting of two highly-charged bare nuclei. The resonance positions and widths depending on the internuclear separation are calculated with the help of the complex-scaling generalized pseudospectral method in modified prolate spheroidal coordinates. The results are applied to estimate the probability of spontaneous positron creation in slow U$^{92+}$--U$^{92+}$ and Cm$^{96+}$--Cm$^{96+}$ collisions

ENDOSCOPIC SURGICAL TREATMENT OF RECURRENT BAKER’S CYSTS

Purpose of the study - to study the causes of synovitis in patients with recurrent Baker’s cyst, to evaluate the effectiveness of endoscopic treatment of popliteal cysts . Materials and methods. From 2009 till 2013 we observed 34 patients with Baker's cyst. In 18 (52.9%) patients of the main group endoscopic technique was applied, in 16 (47.1%) patients of the comparison group a cystic bag was isolated and dissected with open technique, and then cystic gate was sutured. Results. In 10 (55,6%) patients of the main group the pain disappeared in the first postoperative day (

Orbital collapse and dual states of the 5g5g electrons in superheavy elements

The problem of orbital collapse of the $5g$ and $6f$ electrons in atoms of superheavy elements (SHE) is considered. Previously, the presence of the orbital collapse was established for the $4f$ and $5f$ elements of the periodic table. Because of the large centrifugal term for the $f$ and $g$ electrons, the effective radial potential has two wells, one narrow and deep and the other wide but shallow. Depending on the external parameters, the electron can be either localized in the outer well with low binding energy and large average radius or in the inner one with higher energy and smaller radius. In this work, we demonstrate the existence of the orbital collapse for the $5g$ electrons when changing the total angular momentum $J$ of the atom. We also found that for some SHE elements, two different solutions of the same Dirac-Fock equations may coexist, with the $5g$ electron localized either in the inner or outer well. In both cases, the radial wave functions are nodeless. The problem of the dual-state coexistence is studied by the configuration-interaction method in the Dirac-Fock-Sturm orbital basis as well.Comment: 8 pages, 2 figure

MINIMALLY INVASIVE LUMBAR-PELVIC STABILIZATION FOR UNSTABLE PELVIC RING INJURIES

Reconstructive operations for unstable  pelvic ring injuries  in most cases are performed  at later  date  after  trauma (period  of complete  stabilization of the vital functions). The paper presents  treatment outcomes  of three  patients with vertically unstable  pelvic ring injuries where minimally invasive lumbar-pelvic fixation with pedicle screws was applied. The morphology  of sacrum  injury  determined a configuration of the  lumbar-pelvic transpedicular system. In all cases the final surgery was performed  in the early period of traumatic disease, which made it possible to restore  the anatomy of the pelvic ring and obtain good functional outcomes

Lumbopelvic transpedicular fixation of vertically unstable pelvic ring injuries

Introduction Identification of a proper fixation of the posterior pelvic ring is of paramount importance in treatment of patients with vertically unstable pelvic injuries. Material and methods Outcomes of 29 patients with polytrauma and vertically unstable pelvic injuries treated at Level I Trauma Center between 2013 and 2017 were analyzed. The mean age of the patients was 34.8 ± 99 years. The severity of the injuries and patients’ condition were evaluated using Injury Severity Score (ISS), VPKh-P (MT), VPKh-SP, and Yu. N. Tsibin scales (1975) to determine the sequence of treatment and diagnostic procedures. Classification offered by Pape H. C. (2005) was used to evaluate physiological condition. The ISS score was 27.1 ± 9.9. All patients underwent computed tomography (CT) scan of pelvic for preoperative planning. Lumbopelvic transpedicular fixation (LPTF) was employed as a definitive treatment of vertically unstable pelvic ring fractures in all clinical observations. Posterior half-ring morphology, a need for decompression of the nerve roots of the sacral plexus, timing of surgery were considered to decide on LPTF configuration. Results Three-month-to-six-year follow-ups of 22 patients showed good and excellent results achieved in 72.7 % of the cases that are in line with findings reported in the literature. Discussion Biomechanically adequate method of internal fixation is the method of choice in the definitive treatment of vertical unstable pelvic injuries with the possibility of decompression of compromised neural structures. Lumbopelvic fixation with the possibility of simultaneous access for decompression of neural structures is the most optimal technique for these complicated injuries

ПРИМЕНЕНИЕ ДАБИГАТРАНА ЭТЕКСИЛАТА (ПРАДАКСА®) У ПАЦИЕНТОВ С ЗАКРЫТЫМИ ДИАФИЗАРНЫМИ ПЕРЕЛОМАМИ БЕДРА И ГОЛЕНИ

The results of application of dabigatran etexilate in treatment of 56 patients aged 60 to 89 with closed diaphyseal fractures of femur and tibia undergone intramedullary osteosynthesis were studied. The patients were divided into 2 groups. The first group consisted of patients receiving standard anticoaqulant therapy. The second one included patients who used etyek-silat (pradaxa OS) in early postoperative period. The results of treatment in these groups were analysed and compared. Evidence-based significant advantage of dabigatran etexilate (pradaxaR) administration in early postoperative period was revealed.В статье, посвященной применению дабигатрана этексилата (Прадакса®) у пациентов с закрытыми диафизарными переломами бедра и голени, изучены результаты лечения 56 пострадавших, в возрасте от 60 до 89 лет, которым был выполнен интрамедуллярный остеосинтез. Пациенты были разделены на 2 группы. В первую группу вошли больные, которым применялась стандартная антикоагулянтная терапия. Во вторую группу - пациенты, которым в раннем послеоперационном периоде назначался дабигатрана этексилат (Прадакса®). Изучены результаты лечения в группах, проведено их сравнение. Выявлено значимое преимущество применения в раннем послеоперационном периоде дабигатрана этексилат (Прадакса®) с точки зрения доказательной медицины

Выбор оптимальной тактики лечения пострадавших с тяжелой нестабильной травмой таза

Pelvic trauma caused by high-energy forces are accounting for 3 % to 8 % of all traumatic fractures. These are often accompanied by other life-threatening injuries that is a serious tactic problem. There are many publications on the advantages and disadvantages of multi-stage treatment with the Damage Control Orthopedics protocol and Early Total Surgical Care. However, the most difficult category was those who are in a borderline or hemodynamically unstable state.Their treatment is often complicated by acute respiratory distress syndrome (ARDS) and multiple organ failure syndrome (MOFS). The reliable risk assessment, associated with the implementation of a single-stage or multi-stage treatment protocol in patients with unstable pelvic injury, is not sufficient, and surgeon has to choose the treatment protocol based only on own experience.The objective was to analyze the results of using single-stage and multi-stage treatment protocols for patients with unstable pelvic trauma and identify insufficiently researched aspects of each of them.На долю переломов таза, вызванных действием высокоэнергетических сил, приходится от 3 до 8 % всех травматических переломов костей. Эти травмы часто сопровождаются другими жизнеугрожающими повреждениями, представляя собой серьезную тактическую проблему. Имеется большое количество публикаций, посвященных преимуществам и недостаткам многоэтапной тактики оказания помощи Damage Control Orthopedics и ранней полной хирургической помощи Early Total Care. Однако наиболее трудной в отношении выбора тактики является категория пострадавших, находящихся в пограничном или гемодинамически нестабильном состоянии. Их лечение зачастую осложняется такими состояниями, как острый респираторный дистресс-синдром (ОРДС) и полиорганная недостаточность (ПОН). Критерии оценки рисков, связанных с применением одноэтапной и многоэтапной тактики лечения пострадавших с нестабильной травмой таза, не определены в достаточной мере, и хирург вынужден самостоятельно принимать решение о выборе тактики лечения, основываясь в большей степени на собственный опыт.Цель – проанализировать результаты применения одноэтапной и многоэтапной тактик лечения пострадавших с нестабильной травмой таза, а также определить недостаточно исследованные аспекты каждой из них

Особенности диагностики костно-суставной патологии при эндопротезировании тазобедренного и коленного суставов у пациентов, находящихся на хроническом гемодиализе

The objective was the objective assessment of the main osteo-specific laboratory and instrumental diagnostic indicators and their prognostic effect on the outcome of surgical treatment.Material and methods. The study included 72 patients who were divided into 2 groups: 35 (48.6 %) patients with a satisfactory outcome after surgery for year, and 37 (51.4 %) patients with various postoperative complications.Results. The highest statistical significance was indicated by the level of serum vitamin D (p<0.001) and the level of fibrinogen (p<0.001). The average value of the Hounsfield index in the group of patients without complications was 164.5 (Me 51.2), in the group of patients with complications – 71.5 (Me 85.0). The statistical significance (p<0.001) of the Hounsfield index between the two groups of patients was noted. The highest statistical significance was indicated by the level of serum vitamin D (p<0.001) and the level of fibrinogen (p<0.001). A discriminant analysis was performed with the construction of canonical correlation based on the results of laboratory and instrumental indices in order to determine the relationship between the obtained parameters and infectious and common complications.Conclusion. The discriminant prediction formula for infectious complications among patients planned for hip / knee arthroplasty obtained during the study had a high sensitivity (90 %) and specificity (87.1 %).Цель – объективная оценка основных костно-специфических лабораторных и инструментальных диагностических показателей и их прогностического влияния на исход хирургического лечения.Материал и методы. В исследование были включены 72 пациента, которые были разделены на 2 группы: 35 (48,6 %) больных с удовлетворительным исходом после оперативного вмешательства в течение года и 37 (51,4 %) пациентов с различными послеоперационными осложнениями.Результаты. Наибольшую статистическую значимость показывают уровень сывороточного витамина D (р<0,001) и уровень фибриногена (р<0,001). Среднее значение индекса Хаунсфилда в группе пациентов без осложнений было 164,5 (Me=51,2), в группе пациентов с осложнениями – 71,5 (Me=85,0). Отмечается статистическая значимость (p<0,001) индекса Хаунсфилда между двумя группами пациентов. Наибольшую статистическую значимость показывают уровень сывороточного витамина D (р<0,001) и уровень фибриногена (р<0,001). Проведен дискриминантный анализ с построением канонической корреляции по результатам лабораторных и инструментальных показателей с целью определения взаимосвязи полученных параметров с инфекционными, а также общими осложнениями.Выводы. Полученная в ходе исследования дискриминантная формула прогнозирования инфекционных осложнений среди пациентов, планируемых на эндопротезирование тазобедренного/коленного суставов, обладает высокой чувствительностью (90 %) и специфичностью (87,1 %)