Models of mesoscopic time-resolved current detection

Quantum transport in mesoscopic conductors is essentially governed by the laws of quantum mechanics. One of the major open questions of quantum mechanics is what happens if non-commuting observables are measured simultaneously. Since current operators at different times do not commute, the high-frequency correlation functions of the current are realization of this fundamental quantum question. We formulate this problem in the context of measurements of finite-frequency current cumulants in a general quantum point contact, which are the subject to ongoing experimental effort. To this end, we present two models of detectors that correspond to a weak time-resolved measurement of the electronic current in a mesoscopic junction. In both cases, the backaction of the detector leads to observable corrections to the current correlations functions involving the so-called noise susceptibilities. As a result, we propose a reinterpretation of environmental corrections to the finite-frequency cumulants as inevitable effect resulting from basic quantum mechanical principles. Finally we make concrete predictions for the temperature-, voltage-, and frequency-dependence of the third cumulant, which could be verified directly using current experimental techniques.Comment: 19 pages, 5 figures, considerably extended and corrected versio

Using of small-scale quantum computers in cryptography with many-qubit entangled states

We propose a new cryptographic protocol. It is suggested to encode information in ordinary binary form into many-qubit entangled states with the help of a quantum computer. A state of qubits (realized, e.g., with photons) is transmitted through a quantum channel to the addressee, who applies a quantum computer tuned to realize the inverse unitary transformation decoding of the message. Different ways of eavesdropping are considered, and an estimate of the time needed for determining the secret unitary transformation is given. It is shown that using even small quantum computers can serve as a basis for very efficient cryptographic protocols. For a suggested cryptographic protocol, the time scale on which communication can be considered secure is exponential in the number of qubits in the entangled states and in the number of gates used to construct the quantum network

Detection of the Genetic Material of the Viruses Tacheng uukuvirus and Sara tick phlebovirus in Taiga Ticks Collected in the Sverdlovsk, Tomsk Regions and Primorsky Territory of Russia and Their Phylogeny

Extensive spread of tick-borne diseases poses a significant problem for public health and the health of the population living in endemic areas.The aim of the study was to search, analyze genetic material and identify new viral agents of the Phenuiviridae family in taiga ticks collected in Asian regions of Russia using the method of high throughput sequencing.Materials and methods. The study involved 1460 taiga ticks collected in suburban areas of the Tomsk, Yekaterinburg and Primorsky Territory. The genetic material isolated from ticks was sequenced using Illumina technology followed by phylogenetic analysis.Results and discussion. Analysis of the sequencing results made it possible to detect extended nucleotide sequences of the L-gene fragment characteristic of the Phenuiviridae family viruses. We were able to identify 20 nucleotide sequences the length of 250 bp on average in homogenates of Ixodes persulcatus ticks. Eighteen isolates have been identified as members of the genus Uukuvirus and two isolates have been assigned to the genus Phlebovirus, Phenuiviridae family. Phylogenetic analysis has shown that all isolates of the genus Uukuvirus fall under the cluster of Tacheng tick virus 2 belonging to the species Tacheng uukuvirus. They form a separate phylogenetic group which is closely related to two Romanian variants of 2019. Tacheng tick virus 2 was detected in all three surveyed regions of the Asian part of Russia. Two Tomsk isolates of phlebovirus were classified as Sara tick phlebovirus and they clustered with two isolates of phleboviruses from Karelia. Thus, the genetic material of Tacheng tick virus 2 and Sara tick phlebovirus belonging to two genera of the family Phenuiviridae was found in I. persulcatus ticks collected in three geographically different regions of the Asian part of Russia

Measurement of high order current correlators

The feasibility of measuring high-order current correlators by means of a linear detector is analyzed. Two different types of measurements are considered: measurement of fluctuation power spectrum and measurement of unequal-time current correlators at fixed points in time. In both cases, formally exact expressions in terms of Keldysh time-ordered electron current operators are derived for the detector output. An explicit time ordering is found for the current correlators under the expectation operator used in measurements of high order unequal-time current correlators. The situation when a detector measures current correlators at different points of a conductor is considered.Comment: 27 page

Сравнительные результаты экстренной каротидной эндартерэктомии и экстренной каротидной ангиопластики со стентированием в острейшем периоде ишемического инсульта. Результаты многоцентрового исследования

 AIM OF STUDY Study of hospital results of emergency carotid endarterectomy (CEE) and carotid angioplasty with stenting (CAS) in the acute period of acute cerebrovascular accident (ACVA).MATERIAL AND METHODS From January 2008 to August 2020, the study included 615 patients with hemodynamically significant stenosis of the internal carotid arteries (ICA), operated on in the acute period of ischemic stroke (within 3 days from the onset of stroke). Depending on the type of revascularization implemented, all patients were divided into 2 groups: group 1 — CAS (n=312); 2nd group — CEE (n=357). Inclusion criteria were as follows: 1. Mild neurological disorders: NIHSS score 3–8; Modified Rankin Scale score 2 of less; Barthel Scale > 61; 2. Indications for CEE / CAS  according to the current national recommendations; 3. Ischemic focus in the brain not more than 2.5 cm in diameter. Exclusion criteria: 1. Presence of  con-traindications to CEE / CAS. Carotid angioplasty with stenting was performed according to the standard technique; in all cases, distal embolism  protection systems were used. Carot-id endarterectomy was performed  according to the classical and eversion techniques. When the retrograde pressure in the ICA was less than 60% of the systemic pressure, a temporary shunt (TS) was installed. In the postoperative period, all patients underwent multispiral computed tomography (MSCT) of the brain. In the absence of negative dynam-ics in the neurological status, MSCT was performed on the 7th day after the operation, if available, it was performed urgently. The checkpoints were the development of such unfa-vorable cardiovascular events as death, myocardial infarction (MI), stroke / transient is-chemic attack (TIA), “mute” stroke, “mute” hemorrhagic transformations, combinedend-point (death + all strokes / TIA + MI). Strokes were mute if diagnosed according to MSCT, without symptoms.RESULTS In 69% of diabetic patients with anterior myocardial infarction and in 63% of patients with posterolateral MI 12 months after PCI, signs of LV inferiority were revealed in the form of an increase in the indices of end-diastolic and systolic volumes of the LV and low ejection fraction (≤45%). In patients without diabetes, these figures were 18% and 31%, respectively. High concentrations of NT-proBNP on the first day of myocardial infarction after PCI were of the greatest value in the  diagnosis and prognosis of LV UR after 12 months.RESULTS When analyzing hospital complications, significant differences in the frequency of lethal outcome were not obtained (group 1: n=6 (1.92%); group 2: n=8 (2.24%); p=0.98; OR=0.85; 95% CI 0.29–2.49); MI (group 1: n=5 (1.6%); group 2: n=5 (1.4%); p=0.91; OR=1.14; 95% CI 0.32–3.99 ); ACVA (ischemic type) / TIA (group 1: n=5 (1.6%); group 2: n=6 (1.7%); p=0.82; OR=0.95; 95% CI 0.28–3.15), as well as “mute” ACVA (group 1: n=7 (2.2%);  group 2: n=15 (4.2%); p=0.23; OR=0.52; 95% CI 0.21–1.3). However, the vast majority of hemorrhagic transformations (group 1: n=2 (0.64%); group 2:  n=13 (3.6%); p=0.018; OR=0.17; 95% CI 0.03–0.76) and all “mute” hemorrhagic transformations (group 1: n=0; group 2: n=26 (7.3%); p=0.001;  OR=0.02; 95% CI 0.001–0.33) were observed only in the CEE group, which was reflected in the maximum values of the combined end point: group 1: n=22 (7.05%); group 2: n=73 (20.4%); p<0.0001; OR=0.29; 95% CI 0.17–0.48). Thus, in the CEE group, every 5th patient had a complication.CONCLUSION Carotid angioplasty with stenting is the safest method of revascularization for patients in the acute period of ACVA. This is largely due to the reduction in the risk of reperfusion syndrome and the prevention of embolism due to the use of modern protection systems. Carotid  endarterectomy can be performed with comparable efficiency only when a tempo-rary shunt is placed in the internal carotid arteries in the absence of unstable atheroscle-rotic plaque. Цель Изучение госпитальных результатов экстренной каротидной эндартерэктомии (КЭЭ) и каротидной ангиопластики со стентированием (КАС) в острейшем периоде острого нарушения мозгового кровообращения (ОНМК).Материал и методы C января 2008 по август 2020 г. в  исследование вошли 615 пациентов с гемодинамически  значимыми стенозами внутренних сонных артерий (ВСА),  оперированными в острейшем периоде ишемического  инсульта (в течение 3 суток от дебюта ОНМК). В зависимости от реализованного вида реваскуляризации все больные были распределены на две группы: 1-я группа — КАС (n=312); 2-я группа — КЭЭ (n=357). Критериями включения стали: 1. Неврологические нарушения легкой степени: от 3  до 8 баллов по шкале NIHSS; не более 2 баллов по  модификационной шкале Рэнкина; более 61 балла по шкале Бартел; 2. Показания для КЭЭ/КАС согласно действующим  национальным рекомендациям; 3. Ишемический очаг в  головном мозге не более 2,5 см в диаметре.  Критерии  исключения: 1. Наличие противопоказаний к КЭЭ/КАС.  Каротидную ангиопластику со стентированием выполняли по стандартной методике, во всех случаях использовали  системы защиты от дистальной эмболии. Каротидную эндартерэктомию производили по классической и эверсионной методикам. При ретроградном давлении в ВСА  менее 60% от системного устанавливали временный  шунт (ВШ). В послеоперационном периоде всем больным  выполняли мультиспиральную компьютерную томографию  (МСКТ) головного мозга (ГМ). При отсутствии  отрицательной динамики в неврологическом статусе — МСКТ выполняли на 7-е сутки после операции, при наличии  — неотложно. Под контрольными точками понималось  развитие таких неблагоприятных кардиоваскулярных событий, как летальный исход, инфаркт миокарда (ИМ),  ОНМК/транзиторная ишемическая атака (ТИА), «немые» ОНМК, «немые» геморрагические трансформации,  комбинированная конечная точка (смерть + все ОНМК/ ТИА+ИМ). «Немыми» считали инсульты, диагностированные  по данным контрольной МСКТ ГМ, не имеющие  симптоматики.Результаты При анализе госпитальных осложнений  значимые различия не были получены по частоте  летального исхода (группа 1: n=6 (1,92%); группа 2: n=8  (2,24%); р=0,98; ОШ=0,85; 95% ДИ 0,29–2,49); ИМ (группа 1: n=5 (1,6%); группа 2: n=5 (1,4%); р=0,91; ОШ=1,14; 95% ДИ 0,32–3,99); ОНМК (ишемический тип)/ТИА (группа 1: n=5 (1,6%); группа 2: n=6 (1,7%); р=0,82; ОШ=0,95; 95% ДИ 0,28–3,15), а также «немых» ОНМК (группа 1: n=7 (2,2%); группа 2: n=15 (4,2%); р=0,23; ОШ=0,52; 95% ДИ 0,21–1,3). Однако подавляющее большинство геморрагических  трансформаций (группа 1: n=2 (0,64%); группа 2: n=13 (3,6%);  р=0,018; ОШ=0,17; 95% ДИ 0,03–0,76) и все «немые»  геморрагические трансформации (группа 1: n=0; группа 2:  n=26 (7,3%); р=0,001; ОШ=0,02; 95% ДИ 0,001–0,33) были зафиксированы только в группе КЭЭ, что отразилось на  максимальных значениях комбинированной конечной  точки: группа 1: n=22 (7,05%); группа 2: n=73 (20,4%);  р<0,0001; ОШ=0,29; 95% ДИ 0,17–0,48). Таким образом в группе КЭЭ осложнение получил каждый 5-й пациент.Заключение Для больных в острейшем периоде острого нарушения мозгового кровообращения наиболее  безопасным способом реваскуляризации является  каротидная ангиопластика со стентированием. Во многом это обусловлено снижением риска реперфузионного синдрома и профилактикой эмболии благодаря применению современных систем защиты. Каротидная эндартерэктомия может выполняться с сопоставимой эффективностью только при установке временного шунта во  внутренние сонные артерии при условии отсутствия  нестабильной атеросклеротической бляшки.

Energy entanglement in normal metal-superconducting forks

14 pages, 6 figuresThe possibility for detecting energy entanglement in normal metal - superconductor junctions is examined. For the first time we proved that two electrons in a NS structure originating from the same Cooper pair are entangled in the energy subspace. This work follows previous works where spin entanglement was studied in similar circuits. The device consists of a superconducting beam splitter connected to two electronic Mach-Zehnder interferometers. In each arms of the interferometers, energies are filtered with coherent quantum dots. In contrast to previous studies of zero-frequency cross-correlations of electrical currents for this system, attention is drawn to finite-time measurements. This allows to observe two-particle interference for particles with different energies above and below Fermi level. Entanglement is first characterized via the concurrence for the two-particle spatial density matrix. Next, we formulate the Bell inequality, which is written in terms of finite-time noise correlators, and thereby we find a specific set of parameters for which entanglement can be detected

Comparative results of surgical and transcatheter (TAVI) treatment of aortic stenosis in patients over 75 years old

Aim. To assess the results of transcatheter aortic valve implantation (TAVI) in comparison with open surgery for aortic stenosis in patients over 75 years old. Material and methods. We analyzed the results of 33 operations of aortic valve replacement in patients with aortic stenosis performed in the Moscow Municipal Clinical Hospital No. 15 in the period from June 2012 to September 2017. The first group included 21 TAVI operations. In 15 patients TAVI was performed through the femoral artery, 6  — transthoracic through the cardiac apex. All patients with transcatheter intervention were implanted with SAPIEN valves. In the postoperative period all patients showed a decrease in the systolic pressure gradient on the valve to 9,8±4,06 mm Hg. Aortic valve area after the operation has increased on average from 0,72±0,1 cm2 to 1,9±0,3 cm2. For comparison, a control group of 12 patients who underwent aortic valve replacement under cardiopulmonary bypass was formed. All patients had a high operative risk. Euroscore II 6,3±4,9, STS 5,2±3,4.Results. There were no cases of death in the TAVI group. These patients had the following postoperative complications: 3 patients (13,6%)  — complete atrioventricular block, which required permanent pacemaker implantation; it was a significantly more frequent complication of transcatheter interventions. Less frequently in the postoperative period patients had severe acute cardiovascular failure (p=0,001), acute renal failure (p=0,05), paroxysmal atrial fibrillation (p=0,001). The volume of intraoperative blood loss was significantly less in the TAVI group: 147,6±84,4 ml and 666,7±322,9 ml (p=0,05). Mortality in the surgical group was 33% (4 patients). In the surgical group in 2 cases the cause of death was multiple organ failure, in two cases — acute cardiovascular failure. Patients from this group patients had the following postoperative complications: bleeding requiring a resternotomy — 2 (16,7%), pneumonia — 1 (8,3%), heart failure in the postoperative period, requiring prolonged cardiotonic support — 9 (75%), one patient underwent mechanical hemodynamic support, renal failure requiring renal replacement therapy in one patient.Conclusion. Even though surgical aortic valve replacement is the “gold standard” for treating patients with aortic stenosis, the results of operations in the older age group is not sufficient due to the high frequency of postoperative complications. TAVI, proposed by Cribier A, et al. in 2002, gives better results in patients over 75 age group due to the lower incidence of complications in the postoperative period, less intraoperative blood loss. We suppose that it is an alternative for patients of the older age group and high operative risk