Laser induced THz emission from femtosecond photocurrents in Co/ZnO/Pt and Co/Cu/Pt multilayers

The ultrashort laser excitation of Co/Pt magnetic heterostructures can effectively generate spin and charge currents at the interfaces between magnetic and nonmagnetic layers. The direction of these photocurrents can be controlled by the helicity of the circularly polarized laser light and an external magnetic field. Here, we employ THz time-domain spectroscopy to investigate further the role of interfaces in these photo-galvanic phenomena. In particular, the effects of either Cu or ZnO interlayers on the photocurrents in Co/X/Pt (X = Cu, ZnO) have been studied by varying the thickness of the interlayers up to 5 nm. The results are discussed in terms of spin-diffusion phenomena and interfacial spin-orbit torque.Comment: 15 pages, 6 figures, 2 table

Cervical Spine in Scheuermann’s Disease: Review

Background. The state of the cervical spine in patients with Scheuermanns disease has still not been studied enough. This concerns the magnitude of cervical lordosis in the norm and in juvenile kyphosis in both pre- and postoperative periods, as well as the relationship of these changes with the spinopelvic parameters. There is almost no information on the correlation between the state of cervical lordosis and the development of proximal transitional kyphosis. Aim of the study. To determine the features of the cervical spine in patients with Scheuermanns disease in the pre- and postoperative periods by analyzing the literature data. Results. The literature data do not allow us to clearly define the limits of normal in the quantitative assessment of cervical lordosis. The only thing all researchers agree on is that the cervical lordosis should be considered discretely, namely at the C1-C2 and C2-C7 levels. The most commonly used parameters of the cervical-thoracic junction are T1 slope, thoracic inlet angle (TIA) and position of the sagittal vertical axis (SVA). The magnitude of cervical lordosis in Scheuermanns disease varies from 4 to 35, i.e., thoracic kyphosis increase is not always accompanied by the development of compensatory cervical hyperlordosis. In thoracic deformities (the apex is at the level of T10 and cranial), the magnitude of cervical lordosis is significantly greater than that in thoracolumbar deformities (the apex is at the level of T11 and caudal). In the first case, the cervical lordosis (C2-C7) is 19.4-26.2, while in the second one 4.7-8.5. Very few literature data demonstrate that in terms of cervical lordosis dynamics, patients with Scheuermanns disease do not represent a homogeneous group. The only pattern is that the cervical lordosis increases slightly in the longterm postoperative period. The spinopelvic parameters in patients with Scheuermanns disease differ little from the normal ones and almost do not change after corrective interventions. We could not find any publications attempting to relate the risk of PJK to cervical-thoracic junction parameters (T1, TIA, SVA). Conclusion. The state of the cervical spine in patients with severe forms of Scheuermanns disease, subject to surgical correction, has not been studied enough. This concerns the magnitude of cervical lordosis, its dynamics in the postoperative period, its relationship with spinopelvic parameters, as well as the correlation between parameters of transitional cervical-thoracic spine and development of proximal transitional kyphoses. Further studies of this problem are needed

Theory of optical generation and detection of propagating magnons in an antiferromagnet

We report a theory of optical generation and detection of the propagating spin waves in antiferromagnetic materials relevant for ultrafast pump-probe experiments. We derive and solve the equations of motion for antiferromagnetic spins in response to the light-induced effective magnetic field in the linear regime. Different forms of the excitation and the properties of the generated spin waves are analyzed. We theoretically show the selective detection of the spin waves by the magneto-optical Kerr effect. The developed formalism is readily applicable to inform future experiments on antiferromagnetic optomagnonics

Evaluation of the efficiency of innovative forms of healthy lifestyle of students during the implementation of the health-saving project

Objective: to evaluate medical effectiveness of innovative forms of healthy lifestyle development for students of VSMU on the basis of a comprehensive study of the health status and lifestyle of students during the implementation of a health-saving project based on the example of the work of the «AcademicHealthCenter». Materials and methods: to solve these tasks, a complex of medical-sociological (questionnaires), clinical-statistical, biochemical and instrumental research methods was used. The objects of the study were: health indicators, conditions of the educational process, the quality and lifestyle of students of VSMU named after BurdenkoN.N. 537 students took part in the survey. Results: conceptual model on formation of infrastructural, organizational and administrative reserves for improving the quality of preventive medical work in the youth environment was developed and tested using the example of the creation of the «Academic Health Center». Conclusions: the developed model allowed not only to change the technology of rendering medical aid to students, but also to save funds in conditions of a funding gap, improve quality and accessibility of medical services to a socially unprotected category of the population

Rediction of thermal state of billet in the annular heating furnace

В роботі представлена прогнозуюча ELCUT-модель динаміки термічного стану заготовки під час її нагрівання в методичній, зварювальній і томильній зонах кільцевої печі трубопрокатного цеху.In this paper established predictor ELCUT-model of the thermal state of the workpiece during its heating in a methodical, welding and soaking zones of the ring rolling furnace shop

The problem of double thoracic idiopathic scoliosis: a non-systematic literature review

Objective. To analyze the current situation in the community of spine surgeons regarding the determination of the zone of posterior spinal fusion for double thoracic idiopathic scoliosis. Material and Methods. The content of 16 publications containing the results of surgical correction of double thoracic scoliotic deformities was analyzed. The number of studied clinical cohorts was 25, of which in 13 groups only the right-sided main thoracic (MT) curve (MT group) was blocked, and in 12 – both MT and left-sided proximal upper thoracic (PT) curve (MT + PT group). Four parameters were analyzed in both groups: preoperative Cobb angle, preoperative curve mobility, deformity correction, and postoperative deformity progression. Results. Significant differences were found in the MT and MT + PT groups only in two cases: for the initial Cobb angle of the PT curve and the magnitude of its correction (Cobb angle before surgery minus Cobb angle immediately after the intervention). When choosing the extent of the instrumental fusion zone, the authors of the publications included in the review were guided, first of all, by the initial magnitude of the Cobb angle of the proximal thoracic curve. In the MT + PT group, it averaged 37–40° and was 11–13° more than in the MT group. At the same time, PT curve mobility in both groups is not statistically different. The achieved correction was statistically significantly greater in the МT + РT group, despite a more severe proximal curvature as compared to the MT group. Postoperative dynamics of kyphosis (both T2–T5 and T5–T12) is insignificant. The length of the instrumental spinal fusion zone has virtually no effect on the parameters of the sagittal contour of the thoracic spine. A fairly high frequency of the adding-on phenomenon development (20.6 %) indicates the presence of a connection between this complication and the dynamics of PT curve, but the available data are not enough to formulate a final conclusion. Literature data regarding patients’ self-assessment of quality of life after surgical treatment of Lenke types 1 and 2 scoliosis are scarce, although the majority of those operated on assess the result of treatment as positive. Conclusion. The problem of determining the extent of the instrumental fusion zone for double thoracic scoliosis remains unresolved. Most surgeons focus not so much on the mobility of the proximal curve, but on its magnitude. There is no consensus in predicting the development of the adding-on phenomenon; there is little information about changes in the quality of life of patients after surgery. New research is needed

Terahertz Optomagnetism:Nonlinear THz Excitation of GHz Spin Waves in Antiferromagnetic FeBO3

A nearly single cycle intense terahertz (THz) pulse with peak electric and magnetic fields of 0.5 MV/cm and 0.16 T, respectively, excites both modes of spin resonances in the weak antiferromagnet FeBO3. The high frequency quasiantiferromagnetic mode is excited resonantly and its amplitude scales linearly with the strength of the THz magnetic field, whereas the low frequency quasiferromagnetic mode is excited via a nonlinear mechanism that scales quadratically with the strength of the THz electric field and can be regarded as a THz inverse Cotton-Mouton effect. THz optomagnetism is shown to be more energy efficient than similar effects reported previously for the near-infrared spectral range

Femtosecond control of electric currents at the interfaces of metallic ferromagnetic heterostructures

The idea to utilize not only the charge but also the spin of electrons in the operation of electronic devices has led to the development of spintronics, causing a revolution in how information is stored and processed. A novel advancement would be to develop ultrafast spintronics using femtosecond laser pulses. Employing terahertz (10$^{12}$ Hz) emission spectroscopy, we demonstrate optical generation of spin-polarized electric currents at the interfaces of metallic ferromagnetic heterostructures at the femtosecond timescale. The direction of the photocurrent is controlled by the helicity of the circularly polarized light. These results open up new opportunities for realizing spintronics in the unprecedented terahertz regime and provide new insights in all-optical control of magnetism.Comment: 3 figures and 2 tables in the main tex

Long-term results of surgical correction of Scheuermann’s kyphosis

Objective. To analyze long-term results of surgical correction of kyphosis due to Scheuermann’s disease. Material and Methods. Design: retrospective cohort study. The study group included 43 patients (m/f ratio, 34/9). The mean age was 19.1 (14–32) years; the mean postoperative follow-up was 6 ± 10 (5–20) years. Two-stage surgery including discectomy and interbody fusion followed by posterior correction and fusion was conducted in 35 cases (Group A). Eight patients (Group B) underwent only posterior correction and spinal fusion. The following parameters were determined for each patient: thoracic kyphosis (TK), lumbar lordosis (LL) (scoliotic deformity of the thoracic/thoracolumbar spine, if the curve magnitude was > 5°), sagittal vertical axis (SVA), sagittal stable vertebra (SSV), first lordotic vertebra (FLV), proximal junctional angle (PJA) and distal junctional angle (DJA). All measurements were performed immediately before surgery, one week after surgery, and at the end of the follow-up period. All patients answered the SRS-24 questionnaire after surgery and at end of the follow-up period. Results. Groups were comparable in terms of age and gender of patients, body mass index and initial Cobb angle (p < 0.05). The curve decreased from 77.8° to 40.7° in Group A and from 81.7° to 41.6° in Group B. The loss of correction was 9.1° and 6.0° in groups A and B, respectively. The parameters of lumbar lordosis remained normal during the follow-up period. At implant density less than 1.2, deformity correction and correction loss were 44.5° (54.7 %) and 3.9°, respectively (p < 0.05). Proximal junctional kyphosis (PJK) was detected in 21 out of 43 patients (48.8 %). The frequency of PJK was 45.4 % among patients whose upper end vertebra was included in the fusion and 60 % among those whose upper end vertebra was not included. PJK developed in eight (47.8 %) out of 17 patients with kyphosis correction ≥ 50 % and in 13 (50.0 %) of those with correction < 50 %. The rate of DJK development was 39.5 %. The lower instrumented vertebra (LIV) was located proximal to the sagittal stable vertebra in 16 cases, with 12 (75 %) of them being diagnosed with DJK. In 27 patients, LIV was located either at the SSV level or distal to it, the number of DJK cases was 5 (18.5 %); p < 0.05. Only two patients with complications required unplanned interventions. According to the patient questionnaires, the surgical outcome score increases between the immediate and long-term postoperative periods for all domains and from 88.4 to 91.4 in total. The same applies to answer to the question about consent to surgical treatment on the same conditions: positive answers increased from 82 to 86 %. Conclusions. Two-stage surgery, as a more difficult and prolonged one, has no advantages over one-stage operation in terms of correction magnitude and stability of the achieved effect. Surgical treatment improves the quality of life of patients with Scheuermann’s disease, and the improvement continues in the long-term postoperative period