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Abstract Dielectric losses are one of the key factors limiting the coherence of superconducting qubits. The impact of materials and fabrication steps on dielectric losses can be evaluated using coplanar waveguide (CPW) microwave resonators. Here, we report on superconducting CPW microwave resonators with internal quality factors systematically exceeding 5 × 106 at high powers and 2 × 106 (with the best value of 4.4 × 106) at low power. Such performance is demonstrated for 100-nm-thick aluminum resonators with 7–10.5 um center trace on high-resistivity silicon substrates commonly used in Josephson-junction based quantum circuit. We investigate internal quality factors of the resonators with both dry and wet aluminum etching, as well as deep and isotropic reactive ion etching of silicon substrate. Josephson junction compatible CPW resonators fabrication process with both airbridges and silicon substrate etching is proposed. Finally, we demonstrate the effect of airbridges’ positions and extra process steps on the overall dielectric losses. The best quality factors are obtained for the wet etched aluminum resonators and isotropically removed substrate with the proposed ultrasonic metal edge microcutting.

Objective: to evaluate the short-term outcomes of surgical treatment of aortic valve and ascending aorta defects performed through mini-sternotomy using normothermic cardiopulmonary bypass and hyperkalemic cardioplegia via Calafiori technique from May 8, 2019 to May 14, 2020. Materials and methods. The study enrolled 80 patients with isolated aortic valve disease and combined pathology of the aortic root and ascending aorta. It lasted from May 8, 2019 to May 14, 2020. The patients were divided into two groups: Group 1 included 30 patients in whom the upper median J-shaped sternotomy was applied as an access, while Group 2 consisted of 50 patients in whom standard median sternotomy was used as an access. The patients consisted of 43 (53.7%) males and 37 (46.3%) females; the average age was 55.1 ± 11.6 years. All patients were examined before surgery. It revealed no statistically significant differences between the two groups. Results. Group 2 had a 30-day mortality of 2% (n = 1) due to the development of acute heart failure against the background of heart rhythm disturbances. One patient in this group had a late mortality due to acute cerebrovascular accident occurring a month after discharge, which corresponded to 2% (n = 1). There were no deaths in Group 1. In Group 1, there were two conversions (6.7%) to longitudinal median sternotomy. In the first case, it was not possible to restore heart rhythm through repeated defibrillator discharges from mini-sternotomy access due to the presence of an adhesive process in the pericardial cavity. In the second case, ligation of the right internal thoracic artery was required after sternal wire sutures. Artificial ventilation (AV) lasted for 170.9 ± 70.2 minutes in Group 1 and 358.2 ± 169.5 minutes in Group 2. Cardiac activity was independently restored in 23 patients (77%) in Group 1, and in 12 (24%) in Group 2 (p < 0.001). Intraoperative blood loss was 400 ± 150 mL and 850 ± 150 mL (p < 0.05) in Group 1 and Group 2, respectively. In the early postoperative period, it was 200 ± 150 mL in Group 1 and 350 ± 150 mL in Group 2. The length of stay at the intensive care unit and the duration of intensive therapy did not exceed 1 day in both groups. In the early postoperative period, 4 patients in Group 1 (13%) and 27 patients in Group 2 (54%) needed inotropic support (p < 0.001). The need for painkillers and non-steroidal anti-inflammatory drugs was within 3–4 days in Group 1 and 8–10 days in Group 2. In-hospital postoperative period varied from 10 to 16 days in both groups, depending on the severity of the initial condition, presence of concomitant diseases and the need to select an adequate anticoagulant dose. The patients were discharged in satisfactory condition under the supervision of a cardiologist at their homes. There were no inflammatory complications in the access area in both groups during their in-hospital stay. Among the complications in the mid-term postoperative period, two months after discharge, mediastinitis was observed in Group 2. The patient was re-hospitalized, after a course of antibiotic therapy which resolved the mediastinitis; sternal osteosynthesis was performed. Conclusion. Based on the study, it has been shown that this technique reduces the duration of mechanical ventilation, ensures early extubation, decreases blood loss, and, accordingly, ensures the use of replacement therapy, chest stability and a better cosmetic effect. It should be noted that there was no mortality and sternal complications in the patient group with a minimally invasive approach.

Abstract The influence of substrate vacancies on the saturation density and orientation of islands upon vacuum condensation of metals onto ionic crystals is investigated for two specific systems. It is shown that the anomalous temperature dependence of the saturation island density in the high-temperature range can be associated with the mobility of vacancies and their trapping by the condensate-substrate interface. The nature of the discrimination of a 180° position of Au tetrahedral islands within each mirror plane of a CaF2 cleavage upon vacuum condensation in the temperature range of oriented crystallization (350–370°C) is revealed. It is demonstrated by the molecular dynamics method that the discrimination is caused by the predominant nucleation of Au clusters on anion vacancies of the CaF2 surface. [ABSTRACT FROM AUTHOR]