Search for effective treatment techniques for professional athletes with lower back pain

Lower back pain (LBP) is a common complaint of a significant number of the athletes. Both young and elite athletes consult the doctors with complaints about LBP. One of the main causes of LBP is diskal hernia or spondylolysis. The main methods of the treatment of this disease are: spondylosis and surrogation of the lumbar disc. In the medical reports there are positive clinical results using both methods. However, the scientific disputes continue over the comparative evaluation of the effectiveness of the methods of spondylolysis and surrogation of the lumbar disc. The authors analyzed the results of the surgical treatment of the 18 professional athletes. In the period from 2012 to 2013 an operation was performed to these athletes to replace the degenerative intervertebral disk disease at the level of L5-S1. A total resection of the intervertebral disc at the level of the lumbar spine with decompression of the dural sac and the subsequent installation of the functional endoprosthesis - M6-L Artificial Lumbar Disc was performed to the first group of athletes (n = 10). The transforaminal lumbar interbody fusion (TLIF) and transpedicular screws after removing the diskal hernia L5-S1 was performed to the second group of athletes (n = 8). The best clinical result was achieved in the first group of the athletes. Only 8 out of 10 athletes with surrogation of the lumbar disc were able to return to their previous level of sporting achievements for two years after the operation. X-ray results showed the safety of endoprosthesis functions throughout the study period. The six athletes from the second group completed their sports career within 2 years after the spondylolysis. The cause was the increase in degenerative processes at the adjacent spine level and an increase in LBP

Investigation of the stability of nanofluids based on water and carbon nanoparticles synthesized by the electric arc method

In this work, arc discharge synthesis was carried out by sputtering electrodes of various compositions in a helium medium, as a result of which two types of materials containing carbon globules and graphene flakes were obtained. The synthesized materials were characterized with transmission electron microscopy, scanning electron microscopy, and Raman spectroscopy. The effect of the type and concentration of carbon nanoparticles and the type of surfactants on the stability of water-based nanofluids was studied with optical spectroscopy. For carbon globules and water, the mass concentrations of nanoparticles and sodium dodecyl sulfate were determined to obtain a nanofluid based on them stable for 1 month, which are 0.02% and 1%, respectively. It was shown that the use of neonol AF 9-12 at a concentration of 2% didn’t lead to the stabilization of carbon globules with a mass concentration of 0.02% in water. For graphene flakes, the mass concentrations of nanoparticles and stabilizers to obtain a water-based nanofluid stable for 1 month were: 0.02% graphene flakes and 1% SDS, as well as 0.02% graphene flakes and 2% neonol AF 9-12, respectively

Exciton energy spectra in polyyne chains

Recently, we have experimentally observed signatures of sharp exciton peaks in the photoluminescence spectra of bundles of monoatomic carbon chains stabilized by gold nanoparticles and deposited on a glass substrate. Here we estimate the characteristic energies of excitonic transitions in this complex quasi-one-dimensional nanosystem with use of the variational method. We show that the characteristic energy scale for the experimentally observed excitonic fine structure is governed by the interplay between the hopping energy in a Van der Waals quasicrystal formed by parallel carbon chains, neutral-charged exciton splitting, and positive-negative trion splitting. These three characteristic energies are an order of magnitude lower than the direct exciton binding energy

Exciton radiative lifetime in a monoatomic carbon chain

Linear carbon-based materials such as polyyne and cumulene oligomers provide a versatile platform for nano-physics and engineering. Direct gap quasi-1D polyyne structures are promising for the observation of strong and unusual excitonic effects arising due to the two-dimensional quantum confinement. Recently, we reported on the observation of sharp exciton peaks in low temperature photoluminescence spectra of polyyne chains (Kutrovskaya S et al 2020 Nano Lett.20 6502–9). Here, we analyze the time-resolved optical response of this system. We extend the non-local dielectric response theory to predict the exciton radiative lifetime dependence on the band-gap value and on the length of the chain. A good agreement between the experiment and the theory is achieved

Reaction of Push–Pull Enaminoketones and <i>in Situ</i> Generated <i>ortho</i>-Quinone Methides: Synthesis of 3‑Acyl‑4<i>H</i>‑chromenes and 2‑Acyl‑1<i>H</i>‑benzo[<i>f</i>]chromenes as Precursors for Hydroxybenzylated Heterocycles

A simple and efficient method for the synthesis of 4<i>H</i>-chromenes and 1<i>H</i>-benzo­[<i>f</i>]­chromenes containing a trifluoroacetyl or aroyl group in the pyran ring from <i>o</i>-quinone methide precursors and push–pull enaminoketones has been developed. The chromenes are presumably formed through an initial oxa-Diels–Alder reaction, followed by an elimination of amine. The possibility of further transformations of given chromenes to <i>o</i>-hydroxybenzylated pyrazoles, isoxazoles, and pyridines has been demonstrated

Confirmation studies of Soviet research on immunological effects of microwaves: Russian immunology results

International audienceThis paper presents the results of a replication study performed to investigate earlier Soviet studies conducted between 1974 and 1991 that showed immunological and reproductive effects of long-term low-level exposure of rats to radiofrequency (RF) electromagnetic fields. The early studies were used, in part, for developing exposure standards for the USSR population and thus it was necessary to confirm the Russian findings. In the present study, the conditions of RF exposure were made as similar as possible to those in the earlier experiments: Wistar rats were exposed in the far field to 2450 MHz continuous wave RF fields with an incident power density in the cages of 5 W/m2 for 7 h/day, 5 days/week for a total of 30 days, resulting in a whole-body SAR of 0.16 W/kg. Effects of the exposure on immunological parameters in the brain and liver of rats were evaluated using the complement fixation test (CFT), as in the original studies, and an additional test, the more modern ELISA test. Our results, using CFT and ELISA, partly confirmed the findings of the early studies and indicated possible effects from non-thermal RF exposure on autoimmune processes. The RF exposure resulted in minor increases in formation of antibodies in brain tissue extract and the exposure did not appear to be pathological. In addition, a study was conducted to replicate a previous Soviet study on effects from the injection of blood serum from RF-exposed rats on pregnancy and foetal and offspring development of rats, using a similar animal model and protocol. Our results showed the same general trends as the earlier study, suggesting possible adverse effects of the blood serum from exposed rats on pregnancy and foetal development of intact rats, however, application of these results in developing exposure standards is limited. Bioelectromagnetics 31:589-602, 2010. © 2010 Wiley-Liss, Inc