Temporomandibular Disorder and Cerebellopontine Angle Meningioma: Perspectives from Three Medical Specialists

Introduction. The relevance of the study is due to the complexity of the differential diagnosis of Kosten's syndrome and meningioma in the area of the cerebellar bridge angle of the brain, as well as the severe suffering of patientsThe purpose of our study: development of an algorithm for the approach to the differential diagnosis of meningioma of the cerebellar angle and Kosten's syndrome.Materials and methods. To accomplish the set tasks, we examined 22 patients who complained of headache, hearing impairment, sensation of tinnitus, pain and crepitus in the temporomandibular joint during movements of the lower jaw, paresthesia of the oral and nasal mucosa. All patients were assigned studies: cone-beam computed tomography (CBCT) and magnetic resonance imaging (MRI) of the TMJ according to indications.Results. Since complaints can lead patients to see doctors of various specialties, it is necessary to be able to differentiate between Costen's syndrome and a tumor of the cerebral pons-cerebral angle. In Costen's syndrome, the pain most often has an aching character, in contrast to the volumetric formations of the brain, in which the pain is burning, spreading along the branches of the facial or trigeminal nerve. One of the main methods of excluding a brain tumor is magnetic resonance imaging.Conclusions. The most significant modern method for diagnosing Costen's syndrome and meningioma of the cerebellopontine angle is magnetic resonance imaging (MRI) of the TMJ and the brain. Differential signs of Costen's syndrome are distal displacement of the head of the lower jaw, diagnosed by CBCT and MRI, as well as displacement of the articular disc (determined by MRI). A meningioma of the cerebellopontine angle is indicated by the burning nature of pain in half of the face, as well as confirmation of the diagnosis by magnetic resonance imaging of the brain

Electrospinning piezoelectric fibers for biocompatible devices

The field of nanotechnology has been gaining great success due to its potential in developing new generations of nanoscale materials with unprecedented properties and enhanced biological responses. This is particularly exciting using nanofibers, as their mechanical and topographic characteristics can approach those found in naturally occurring biological materials. Electrospinning is a key technique to manufacture ultrafine fibers and fiber meshes with multifunctional features, such as piezoelectricity, to be available on a smaller length scale, thus comparable to subcellular scale, which makes their use increasingly appealing for biomedical applications. These include biocompatible fiber-based devices as smart scaffolds, biosensors, energy harvesters, and nanogenerators for the human body. This paper provides a comprehensive review of current studies focused on the fabrication of ultrafine polymeric and ceramic piezoelectric fibers specifically designed for, or with the potential to be translated toward, biomedical applications. It provides an applicative and technical overview of the biocompatible piezoelectric fibers, with actual and potential applications, an understanding of the electrospinning process, and the properties of nanostructured fibrous materials, including the available modeling approaches. Ultimately, this review aims at enabling a future vision on the impact of these nanomaterials as stimuli-responsive devices in the human body

Получение полых полуфабрикатов изделий из медных сплавов электротехнического назначения способом винтовой прокатки

The article proposes a process for obtaining semi-finished products in the form of pipes made of copper alloys for electrical applications using the screw rolling method. The paper presents the results of experimental piercing and rolling of pipe samples made of Cu–0.75Cr copper alloy billets with a diameter of 45 mm. The 43.5×10.0 mm samples obtained after piercing using a two-roll screw rolling mill had exact geometrical dimensions: outer diameter deviation at the front end was up to 1 %, at the back end – up to 2.4 %; relative variation in wall thickness at the front end was 0.3÷0.5 %, at the rear end – 0.5÷1.0 %. Then pierced pipe samples were rolled using a three-roll radial-shear rolling (RSR) mini mill with a different total degree of reduction – samples were obtained with an outer diameter of 30, 25 and 18 mm. The reduction process was analyzed from the point of view of internal hole stability and deformation. In case of 30 % relative reduction of the outer diameter, rolling without a mandrel is accompanied by wall thickening. In this case, inner diameter deviations are within acceptable limits. The experiments on obtaining samples from the Cu–0.75Cr alloy by screw piercing and reduction in the RSR mill show that this scheme can be implemented in principle in industry. At the same time it is necessary to define more exactly deformation parameters (degree of deformation, choice of reduction scheme) to obtain a quality product. Various options for heat treatment (HT) of the obtained pipe samples and the effect of the HT method on electrical conductivity and hardness are considered. Samples after piercing had a conductivity of 59.3 % IACS. The maximum electrical conductivity of 76.7 % IACS was obtained on samples after quenching from a temperature of 1020 °C and aging at 450 °C for 3 h. The results of the work show the fundamental possibility of obtaining semi-finished products from copper alloys for electrical purposes using the screw rolling method.Предложен способ получения полуфабрикатов в виде труб из медных сплавов электротехнического назначения методом винтовой прокатки. Представлены результаты экспериментальной прошивки и прокатки образцов труб из заготовок медного сплава Cu–0,75Cr диаметром 45 мм. Полученные образцы размером 43,5×10,0 мм после прошивки в двухвалковом стане винтовой прокатки имели точные геометрические размеры: отклонение по наружному диаметру на переднем конце – до 1 %, на заднем конце – до 2,4 %, относительная поперечная разностенность на переднем конце составила 0,3÷0,5 %, на заднем конце – 0,5÷1,0 %. Далее прошитые образцы труб были прокатаны на трехвалковом министане радиально-сдвиговой прокатки (РСП) с разной суммарной степенью обжатия – получены образцы с наружным диаметром 30, 25 и 18 мм. Процесс редуцирования проанализирован с точки зрения стабильности и формоизменения внутреннего отверстия. При относительном обжатии наружного диаметра на 30 % прокатка без оправки сопровождается увеличением толщины стенки. При этом отклонения внутреннего диаметра находятся в допустимых пределах. Проведенные эксперименты по получению образцов из сплава Cu–0,75Cr способом винтовой прошивки и редуцирования в стане РСП показывают, что данная схема может быть принципиально реализована в промышленности. В то же время для получения качественного продукта необходимо уточнение параметров деформации (степени деформации, выбора схемы редуцирования). Рассмотрены различные варианты термообработки (ТО) полученных образцов труб и влияние способа ТО на электропроводность и твердость. Образцы после прошивки имели электропроводность 59,3 % IACS. Максимальная электропроводность 76,7 % IACS получена на образцах после закалки с температуры 1020 °С и старения при 450 °С в течение 3 ч. Результаты работы показывают принципиальную возможность получения полуфабрикатов изделий из медных сплавов электротехнического назначения способом винтовой прокатки

Modeling and Synchrotron Data Analysis of Modified Hydroxyapatite Structure

The results are based on the first principal modeling and calculations for hydroxyapatite (HAP) nanostructures as native as well surface modified, charged and having various defects (H and OH vacancies, H internodes). HAP structures having being studied using Local Density Approximation (LDA) method with calculations of Density of States (DOS) allow us analyzing the experimental forbidden energy gap (Eg) and work function data. Molecular modeling by HyperChem is confirmed by photoelectron monochromatic measurements up to 6 eV and photoluminescence (PL) data from synchrotron DESY experimental data up to 30 eV values. Brief analysis of the influence of heating, microwave radiation, hydrogenation, x-rays and synchrotron radiation on HAP surface is presented in this work. New data of the structure of modified hydroxyapatite are obtained. The determined energy levels for H internodes is EH-int ~ Ev + (1.5–2.0) eV, while for OH vacancy energy is in the range of EOH-vac ~ Ev ~ Ev + (2.9–3.4) eV inside the forbidden zone Eg. The analysis of PL emission allows us to conclude that these energies are close to observed main PL spectral line 420 nm (2.95 eV), and consequently OH vacancy could play the leading role in the surface energy levels changes and charging. But the influence of the inserted hydrogen is revealed too through excitation from most deep valence band levels due to existence of close overlapped molecular orbital with phosphorus atoms in the excited states. Both defects are observed by PL emission spectrum under synchrotron excitation energy in diapason ~8.5–14.5 eV

An Attempt to Produce the Implanted 22\text{}^{22}Na Source for Positron Spectrometry

Preliminary results of $\text{}^{22}$Na implantation into the metal foils in order to produce the positron source for annihilation experiments are presented

Modified Hydroxyapatite Structure and Properties: Modeling and Synchrotron Data Analysis of Modified Hydroxyapatite Structure

First principle modeling and calculations of hydroxyapatite both native and surface modified and having various defects (OH vacancies, H inter-nodes) were performed. Local Density Approximation method used with calculations of Density of States allows us to analyze the experimental obtained work function data. Molecular modeling was confirmed by photo-electron measurements up to 6.5eV and photoluminescence experimental data from synchrotron DESY up to 30eV. Brief analysis of the influence of heating, microwave radiation, hydrogenation, and synchrotron radiation on hydroxyapatite surface is presented in this work. New data on the structure of modified hydroxyapatite are obtained