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

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

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

Some Specifics of Defect-Free Poly-(o-aminophenylene)naphthoylenimide Fibers Preparation by Wet Spinning

A series of model experiments were carried out on drops of poly-(o-aminophenylene)naphthoylenimide (PANI-O) solutions in N-methyl-2-pyrrolidone (NMP) surrounded by a coagulant of different compositions as starting points of defect-free fibers spinning by the wet method. An influence of compositions of dopes and multicomponent coagulants on the diffusion kinetics and drop morphology during coagulation has been investigated. It is shown that the defining parameters of the coagulation process are viscoelastic properties of the polymer solution and the diffusion activity of the coagulant, meaning not only the rate of coagulation but also the presence/absence of macro defects in the resulting fiber. The optimal morphology of as-spun fibers is obtained by coagulation of solution in a three-component mixture containing solvent and two precipitants of different activity (water and ethanol). The chosen coagulating mixture was used for the fiber spinning of PANI-O with different molecular weights dopes, and fibers with sufficiently high strength (~250 MPa), moduli (~2.1 MPa), and elongation at break (50%) were obtained

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

Helium Nanodroplet Study of the Hydrogen-Bonded OH Vibrations in HCl–H₂O Clusters

Mixed (HCl)_<i>N</i>(H₂O)_<i>M</i> clusters have been assembled in He droplets from the constituting molecules. Spectra of the clusters were obtained in the range of hydrogen-bonded OH vibrations (3100–3700 cm^–1) by infrared laser depletion spectroscopy. The observed bands were assigned to cyclic hydrogen-bonded aggregates containing up to two HCl and three H₂O molecules. The obtained frequencies are in good agreement with the results of harmonic quantum chemical calculations upon appropriate uniform shifts mimicking anharmonic corrections. Although larger clusters containing up to six water molecules were also produced in the droplets, their spectra were found to contribute to the unresolved signal in the range 3250–3550 cm^–1. The fact that no narrow bands could be unambiguously assigned to the mixed clusters containing more than three water molecules may indicate that such clusters exist in many isomeric forms that lead to overlapped and unresolved bands giving rise to broad structureless features. Another possible explanation includes the formation of elusive zwitterionic clusters, whose bands may have considerable breadth due to electrostatic coupling of different vibrational modes and concomitant intramolecular vibrational relaxation