Gapful electrons in a vortex core in granular superconductors

We calculate the quasiparticle density of states (DoS) inside the vortex core in a granular superconductor, generalizing the classical solution applicable for dirty superconductors. A discrete version of the Usadel equation for a vortex is derived and solved numerically for a broad range of parameters. Electron DoS is found to be gapful when the vortex size $\xi$ becomes comparable to the distance between neighboring grains $l$. Minigap magnitude $E_g$ grows from zero at $\xi \approx 1.4 l$ to third of superconducting gap $\Delta_0$ at $\xi \approx 0.5 l$. The absence of low-energy excitations is the main ingredient needed to understand strong suppression of microwave dissipation recently observed in a mixed state of granular Al

Instability of the Knee Joint Before and After Reconstruction of the Anterior Cruciate Ligament According to the Questionnaire

Background: The instability of the knee joint after a rupture of the anterior cruciate ligament in recent decades has acquired the character of a meme among Russian orthopedists with a very wide use and meaning. Aim: In this study, we tried to find out how often the phenomenon of instability occurs and how it can be associated with joint injury. Methods: The method of questioning, collecting anamnesis in patients at the primary orthopedic appointment and in patients after surgical reconstruction by the method of questioning was used. Results: The data collected in 433 patients with a verified rupture of the anterior cruciate ligament showed that 77% experienced a feeling of instability in the knee joint, and 19% did not experience them at all. Arthroscopic reconstruction was performed in 297 patients, 71 of them were surveyed. The period of time from surgery to questioning was 6.5 years on average. Not all patients can note the moment of injury. Even if there was an injury to the knee joint, 10% of patients do not note the development of instability immediately after injury. The duration of the sensation of instability in the knee joint after injury varies from one week to a year or more. The very moment of joint instability is accompanied by pain in more than half of the cases. At the same time, 12% of the respondents had no pain. A third of the respondents had never noted episodes of instability in the knee joint before surgical reconstruction. But 11% had such episodes daily. In the postoperative period, 27% note the recurrence of joint instability at different times. Conclusions: Thus, an ACL tear does not equal knee instability. Instability is not a condition, but a short-term episode that occurs during the period of support and leads to buckling of the limb

Targeted training of the function of walking according to the stance and single support phase in patients in the early recovery period of cerebral stroke

Background: The phases of support and single support on a limb are significant basic parameters of walking (phase of support means the whole limb support time, while the phase of single support is when only one limb is on the ground). Both can be used as targets for biofeedback training. Aim: to investigate the effectiveness of both target parameters for training the function of walking with biofeedback in patients in the early recovery period of cerebral stroke. Methods: The study involved 40 patients, 20 in each group, who underwent a training course to harmonize walking: the first group for the period of support, and the second group for the period of single support. The control group of healthy people also consisted of 20 people. We studied the spatiotemporal parameters of walking at an arbitrary pace at the beginning and after the end of the training course, as well as classical clinical scales. The treadmill training consisted of 10 sessions. Results: The clinical and biomechanical parameters of walking changed their values in the direction of a significant improvement in the performance. At the same time, the biomechanical parameters of the second group indicated a more severe functional state before the start of the treatment, with the same clinical parameters according to the Barthel scale, Rivermead Mobility Index, modified Rankin scale, rehabilitation routing scale, and manual muscle testing. In the first group, indirect data were obtained on the possible effect of the target indicator on the training and direct data on its effect on the function of a healthy limb, which also allows increasing the load on the paretic one. In the second group, there were no reliable data on the effect of biofeedback training on the functional outcome. Conclusion: The conducted study showed that the classical clinical assessment of the patient's condition may not correspond to the instrumental functional study of walking. When using the support period as the training target parameter, indirect evidence was obtained that such a training is effective

Хронические нарушения сознания: клинические рекомендации Общероссийской общественной организации «Федерация анестезиологов и реаниматологов»

Хронические нарушения сознания (ХНС) представляют собой синдромы тяжелого поражения центральной нервной системы, приводящие к длительной грубой инвалидизации и требующие значительных усилий по лечению и реабилитации, которые ложатся на медицинские учреждения и на плечи близких пациентов. ХНС развиваются у пациентов после комы и характеризуются наличием бодрствования при полном или практически полном отсутствии признаков осознанного поведения. К ХНС относятся вегетативное состояние (ВС) и состояние минимального сознания (СМС). Также для описания начальных стадий этих состояний используется термин «продленное нарушение сознания» (ПНС). Отдельно выделяют выход из СМС — состояние, которое формируется по мере восстановления когнитивных функций. Диагностика ХНС основывается на многократном структурированном клиническом осмотре с применением специализированных шкал при условии исключения обратимых причин нарушения сознания. Лечение пациентов с ХНС включает в себя поддержание жизненно важных функций, обеспечение оптимального питания и борьбу с типичными осложнениями и сопутствующими состояниями (пролежни, спастичность, боль, пароксизмальная симпатическая гиперактивность и др.). У пациентов с ХНС должна проводиться реабилитация с участием мультидисциплинарной реабилитационной команды в объеме, который определяется проблемами и возможностями конкретного пациента. Наиболее эффективной реабилитация является при условии ее раннего начала. На данный момент однозначных доказательств эффективности каких-либо специфических методов, направленных на восстановление сознания, не получено; изучается ряд соответствующих фармакологических и нефармакологических вмешательств, обязательным условием применения которых является максимально возможная коррекция соматических проблем пациента. Важную роль в ведении пациентов с ХНС играет вовлечение близких пациента, которые, в свою очередь, нуждаются в получении объективной практической информации о состоянии своего родственника и о направлениях реабилитации, а также в психологической помощи

A Study of Biofeedback Gait Training in Cerebral Stroke Patients in the Early Recovery Phase with Stance Phase as Target Parameter

Walking function disorders are typical for patients after cerebral stroke. Biofeedback technology (BFB) is currently considered effective and promising for training walking function, including in patients after cerebral stroke. Most studies recognize that BFB training is a promising tool for improving walking function; however, the data on the use of highly selective walking parameters for BFB training are very limited. The aim of our study was to investigate the feasibility of using BFB training targeting one of the basic parameters of gait symmetry—stance phase duration—in cerebral stroke patients in the early recovery period. The study included 20 hemiparetic patients in the early recovery period after the first hemispheric ischemic stroke. The control group included 20 healthy subjects. The BFB training and biomechanical analysis of walking (before and after all BFB sessions) were done using an inertial system. The mean number of BFB sessions was nine (from 8 to 11) during the three weeks in clinic. There was not a single negative response to BFB training among the study patients, either during the sessions or later. The spatiotemporal parameters of walking showed the whole syndrome complex of slow walking and typical asymmetry of temporal walking parameters, and did not change significantly as a result of the study therapy. The changes were more significant for the functioning of hip and knee joints. The contralateral hip amplitude returned to the normal range. For the knee joint, the amplitude of the first flexion increased and the value of the amplitude of hyperextension decreased in the middle of the stance phase. Concerning muscle function, the observed significant decrease in the function of m. Gastrocnemius and the hamstring muscles on the paretic side remained without change at the end of the treatment course. We obtained positive dynamics of the biomechanical parameters of walking in patients after the BFB training course. The feasibility and efficacy of their use for targeted correction need further research

Gapful electrons in a vortex core in granular superconductors

We calculate the quasiparticle density of states (DoS) inside the vortex core in a granular superconductor, generalizing the classical solution applicable for dirty superconductors. A discrete version of the Usadel equation for a vortex is derived and solved numerically for a broad range of parameters. Electron DoS is found to be gapful when the coherence length $\xi$ becomes comparable to the distance between neighboring grains $l$. Minigap magnitude $E_g$ grows from zero at $\xi \approx 1.4 l$ to third of superconducting gap $\Delta_0$ at $\xi \approx 0.5 l$. The absence of low-energy excitations is the main ingredient needed to understand strong suppression of microwave dissipation recently observed in a mixed state of granular Al

Wideband waveguide loading impedance matching on the basis of photonic crystals with nanometer metal layers

Theoretically shown and experimentally proven is the possibility of creating wideband matched loading on the basis of photonic crystals, composed of alternating nanometer metal and isolator layers with different electro-physical parameters

Effect of Sn for the dislocation-free SiSn nanostructure formation on the vapor-liquid-crystal mechanism

Structures with tin-rich island arrays on silicon pedestals were obtained by molecular beam epitaxy using Sn as a catalyst for the growth of nanostructures. A tin island array was used further to study the growth of nanostructures in the process of Si deposition on the surface with Sn islands. It was established that, during the growth on the vapor-liquid-crystal mechanism, tin-rich islands are formed on faceted pedestals. A nanostructured cellular surface was formed between the islands on pedestals. The analysis of the elemental composition of the obtained nanostructures was performed by the methods of energy dispersive X-ray spectroscopy and photoelectron spectroscopy. It is shown that tin-rich islands can contain up to 90% tin, whereas the pedestal consists of silicon. The transmission electron microscopy data demonstrated a distinct crystal structure of tin-rich islands and silicon pedestals, as well as the absence of dislocations in the structures with island arrays on the faceted pedestals. The facet tilt angle is 19° and corresponds to the (311) plane. The photoluminescence signal was observed with a photoluminescence maximum near the wavelength of 1.55 μm

Nucleophilic Ring Opening of Donor–Acceptor Cyclopropanes with the Cyanate Ion: Access to Spiro[pyrrolidone-3,3′-oxindoles]

The nucleophilic ring opening of donor–acceptor cyclopropanes with the cyanate ion is reported for the first time. Cyclopropanes, spiro-activated with oxindole fragments as acceptors, are shown to undergo transformations into biologically relevant spiro­[pyrrolidone-3,3′-oxindoles] while being treated with potassium cyanate under microwave assistance