Temperature-induced topological phase transition in HgTe quantum wells

We report a direct observation of temperature-induced topological phase transition between trivial and topological insulator in HgTe quantum well. By using a gated Hall bar device, we measure and represent Landau levels in fan charts at different temperatures and we follow the temperature evolution of a peculiar pair of "zero-mode" Landau levels, which split from the edge of electron-like and hole-like subbands. Their crossing at critical magnetic field $B_c$ is a characteristic of inverted band structure in the quantum well. By measuring the temperature dependence of $B_c$, we directly extract the critical temperature $T_c$, at which the bulk band-gap vanishes and the topological phase transition occurs. Above this critical temperature, the opening of a trivial gap is clearly observed.Comment: 5 pages + Supplemental Materials; Phys. Rev. Lett. (accepted

Temperature-driven single-valley Dirac fermions in HgTe quantum wells

We report on temperature-dependent magnetospectroscopy of two HgTe/CdHgTe quantum wells below and above the critical well thickness $d_c$. Our results, obtained in magnetic fields up to 16 T and temperature range from 2 K to 150 K, clearly indicate a change of the band-gap energy with temperature. The quantum well wider than $d_c$ evidences a temperature-driven transition from topological insulator to semiconductor phases. At the critical temperature of 90 K, the merging of inter- and intra-band transitions in weak magnetic fields clearly specifies the formation of gapless state, revealing the appearance of single-valley massless Dirac fermions with velocity of $5.6\times10^5$ m$\times$s$^{-1}$. For both quantum wells, the energies extracted from experimental data are in good agreement with calculations on the basis of the 8-band Kane Hamiltonian with temperature-dependent parameters.Comment: 5 pages, 3 figures and Supplemental Materials (4 pages

The conditions of injury when playing hockey

The article presents data from modern foreign and domestic scientific sources about the most common injuries when playing hockey, as well as measures to prevent injuries in this sport

Pain development and analgesia in athletes with ankle joints and ligaments injury

The pain feeling in athletes results from nociceptive and antinociceptive systems activity. Mostly pain follows injuries. Ankle joints and ligaments injury is one of the most often trauma. Pain intensity directly depends on the number of injured structures and the degree of the injury. Besides that pain intensity depends upon various factors such as gender and age. The history of injuries can increase the risk of repeated injuries and pain may become chronic. Psycho-emotional experiences during the competition can lead to pain without physical injuries. Anesthesia is important aspect in athletes’ life and it must be effective. Not all currently available medication are approved by the World Anti-Doping Agency. Every year “WADA Prohibited List” is reviewed and every athlete must follow it. The permitted and most effective methods of pain relief for joints and ligaments injury are cooling aerosols, non-steroidal anti-infl ammatory drugs and kinesio taping. Each of these methods has its own characteristics

Rehabilitation after stroke. The role of drug therapy

Of 400,000 strokes occuring in Russia every year, 75% are first and 25% repeated. The majority of cases (about 89%) are ischemic stroke, 17% are intracerebral hemorrhage, and about 3% - subarachnoid hemorrhage [10]. According to European studies, in every 100 000 of people there are 600 people who survived stroke, of which 60% remain disabled. Due to population aging the incidence of stroke is growing. Stroke prevention (including recurrent strokes) and rehabilitation of those who survived stroke has become an actual medical and social problem

Stroke patient seeing a neurologist

Stroke is one of the leading causes of death and disability of the population. Recently, there has been an increase in the incidence of stroke among people of working age and a "rejuvenation" of stroke. The article tells about the algorithm for post-stroke patient management, modern methods of secondary prophylaxis of stroke aimed at prevention of recurrent cerebral circulation disorders and syndrome approach to the treatment of stroke patients

Dyscirculatory encephalopathy: algorithm for diagnosis and treatment in patients with arterial hypertension

The paper analyzes clinic symptomatology and an algorithm for diagnosis, preventive and syndromic treatment, and rehabilitation in patients with different forms of hypertensive dyscirculatory encephalopathy, such as subcortical arteriosclerotic encephalopathy and hypertensive multi-infarct encephalopathy