55 research outputs found
The clinical and anatomical analysis of the reasons of unsatisfactory results of block anesthesia at lower jaw
Цель исследования состояла в изучении и анализе причин, которые снижают клиническую эффективность проводниковых анестезий на нижней челюсти. В ходе исследования был определён ряд факторов, ответственных за снижение эффективности анестезий и развитие осложнений. При препарировании сагиттальных распилов головы человека, а также компьютерной томографии были установлены области депонирования местноанестезирующего раствора. Исследования показали что, главным фактором является ряд особенностей анатомического строения целевого пункта мандибулярной анестезии и, как следствие, низкая локализация анестезирующего раствора в
области целевых нервов.Мета дослідження полягала у вивченні і аналізі причин, які знижують клінічну ефективність провідникової анестезії на нижній щелепі.
В ході дослідження були визначені ряд чинників, відповідальних за зниження ефективності анестезії і розвиток ускладнень. При препаруванні сагиттальних розпилів голови людини, а також комп'ютерній томографії були встановлені області депонування місцевоанестезуючого розчину.
Дослідження показали що, головним чинником є ряд особливостей анатомічної будови цільового пункту мандібулярной анестезії і, як наслідок, низька локалізація анестезуючого розчину в області цільових нервів. Ключові слова. провідникова анестезія, нижня щелепа, анатомічна будова.The aim of the investigation is to study and analyze the reasons, reducing clinical effectiveness of block anesthesia at lower jaw. At investigation the certain factors, responsible for the reduction of the efficiency of anesthesia and development of complications, were determined. The areas of depositing of local anesthetic solution were found at biotomy of sagittal section of human head and computed tomographic scanning. The studies have shown that the main factor is some peculiarities of anatomic structure of target point of mandibular anesthesia and, consequently, the low location of anesthetic solution at the area of target nerves
Spectroscopic and photoluminescence characterization of Eu 3+-doped monoclinic KY(WO4)2 crystal
Monoclinic 2 at% Eu-doped KY(WO4)2 is grown by top-seeded solution growth method. Polarizationresolved absorption and stimulated-emission cross-section spectra are determined for this crystal. Spectroscopic properties of Eu:KY(WO4)2 are modeled within conventional Judd–Ofelt theory, as well as theory of f–f transition intensities for systems with anomalously strong configuration interaction, yielding absorption oscillator strengths, luminescence branching ratios and radiative lifetime of 5D0 state. The impact of excited-state absorption from this state on possibility of laser operation is discussed. Photoluminescent properties of Eu:KY(WO4)2 are determined. This crystal provides intense red emission with CIE coordinates x¼0.670, y¼0.329
Spectroscopy of tetragonal Eu:NaGd(WO4)2 crystal
We report on growth and detailed spectroscopic study of Eu3ю-doped tetragonal sodium gadolinium double tungstate, Eu:NaGd(WO4)2, a new promising crystal for deep-red lasers. Large-volume crystal doped with 4.9 at.% Eu is grown by Czochralski method along the [001] crystallographic direction. Absorption of Eu3ю ions is studied at room temperature (RT) and at 6 K. For the absorption band related to the 7F1 / 5D1 transition suitable for pumping of Eu:NaGd(WO4)2, the maximum cross-section is sabs ј 1.2 _ 10_21 cm2 at 535.5 nm with the full width at half maximum (FWHM) of 3.1 nm (at RT, for E jj a polarization). For the 5D0 / 7F4 transition, the maximum stimulated-emission cross-section is sSE ј 1.6 _ 10_21 cm2 at 698.3 nm (RT, E jj c polarization). Lifetime of the 5D0 state is 490 ± 10 ms (at RT). Under UV excitation, Eu:NaGd(WO4)2 provides intense red emission with CIE coordinates (x ј 0.671, y ј 0.329)
Cardiac lymphatics in health and disease
The lymphatic vasculature, which accompanies the blood vasculature in most organs, is indispensable in the maintenance of tissue fluid homeostasis, immune cell trafficking, and nutritional lipid uptake and transport, as well as in reverse cholesterol transport. In this Review, we discuss the physiological role of the lymphatic system in the heart in the maintenance of cardiac health and describe alterations in lymphatic structure and function that occur in cardiovascular pathology, including atherosclerosis and myocardial infarction. We also briefly discuss the role that immune cells might have in the regulation of lymphatic growth (lymphangiogenesis) and function. Finally, we provide examples of how the cardiac lymphatics can be targeted therapeutically to restore lymphatic drainage in the heart to limit myocardial oedema and chronic inflammation.Peer reviewe
Композиционные материалы системы эпоксидная смола–W для радиационной защиты от гамма-излучения
Сomposite materials based on the epoxy resin–W system with varying W content (0–80 %) were obtained using the method of chemical curing. Microstructural investigations of the samples showed that with increasing W content there is a more uniform distribution of grains in the epoxy resin matrix could be observed. Agglomeration of W grains is noted for samples with filler content up to 40 %. Statistical analysis of the grain size of the initial W powder revealed that the probable diameter of W grains is 475 nm. The values of effective and relative densities of the experimental samples were obtained using the Archimedes method. The effective density varied from 1.16 to 4.36 g/cm3 with W powder content rising. The relative density values received ranged from 91 to 94 %, indica ting that there were no significant defects in the samples. X-ray diffraction analysis showed the presence of vcc-W and WO2 phases, indicating the oxidation of W in the thin surface layer of the powder. Calculation in Phy-X/PSD software allowed to evaluate the gamma radiation shielding efficiency for the epoxy resin–W system composite materials in 0.8–2.5 MeV energy range. It was observed that samples with filler content of 60 and 80 % were the most suitable for radiation shielding. It was found that the addition of W powder to the epoxy matrix contributed to the reduction of half attenuation layer values by 3.5 times from 9.448 to 2.672 cm for samples with 0 and 80 % W content, respectively, for 1.25 MeV radiation energy. The obtained results demonstrate the high efficiency of the proposed composite materials for shielding gamma radiation, which makes them a perspective candidate for manufacturing radiation shields.С использованием метода химического отверждения получены композиционные материалы на основе системы эпоксидная смола–W с варьированием содержания W от 0 до 80 %. Проведенное исследование микроструктуры образцов показало, что при увеличении содержания W наблюдается более равномерное распределение зерен в матрице эпоксидной смолы. Для образцов с содержанием наполнителя до 40 % отмечена агломерация зерен W. Статистический анализ размеров зерен исходного порошка W выявил, что вероятный их диаметр составляет 475 нм. Получены значения эффективной и относительной плотностей экспериментальных образцов с помощью метода Архимеда. Эффективная плотность изменялась в пределах от 1,16 до 4,36 г/см3 с увеличением содержания порошка W. Значения относительной плотности варьировались от 91 до 94 %, что свидетельствовало об отсутствии существенных дефектов при проведении испытания. Рентгеноструктурный анализ показал наличие фаз ОЦК-W и WO2, что указывает на окисление W в тонком поверхностном слое материала. Моделирование в программном обеспечении Phy-X/PSD позволило оценить эффективность экранирования от гамма-излучения композиционных материалов при энергии излучения в диапазоне 0,8–2,5 МэВ. Образцы с содержанием наполнителя 60 и 80 % оказались наиболее подходящими для создания экранов радиационной защиты. Обнаружено, что добавление порошка W в эпоксидную матрицу способствовало уменьшению значений слоя половинного ослабления в 3,5 раза с 9,448 до 2,672 см для образцов с содержанием W 0 и 80 % соответственно при энергии излучения гамма-квантов 1,25 МэВ. Полученные результаты демонстрируют высокую эффективность предложенных композиционных материалов в экранировании гамма-излучения, что делает их достойным вариантом для создания экранов радиационной защиты
Effect of the NO concentration on the ratio I₅₅₇.₇/I₄₂₇.₈ in auroras
We have examined the effect of the nitrogen oxide concentration on the ratio between λ557.7 nm and λ427.8 nm emission intensities in auroras caused by precipitating electron fluxes, using the numerical simulation method. The ratio I₅₅₇.₇/I₄₂₇.₈ has been shown to strongly depend on the NO concentration: the ratio decreases from 7 to 2 with increasing NO maximum concentration at the height profile from 10⁷ to 3·10⁹. This fact is in satisfactory agreement with experimental data.The effect of nitric oxide on the ratio has been demonstrated to occur through the excitation channel of the emission λ557.7 nm, namely, the dissociative recombination of the molecular oxygen ion O⁺₂+eₜₕ due to the ion deactivation by collision reaction with nitric oxide O⁺₂+NO
Atrio-aortic erosion caused by Amplatzer Atrial Septal Occluder - a case report
BACKGROUND In specialized centers, percutaneous closure using specific occluders is the first-choice treatment in atrial septal defects (ASD). Late complications after this intervention, such as erosion of the aorta or the atria, are rare and have not been sufficiently approached and dealt with in literature. In our clinic we have been faced with the problematic situation of diagnosing and treating such cases. That is why, we have decided to share our experience with other colleagues. CASE PRESENTATION We present two cases of severe late complications after percutaneous closure of atrial septal defects (ASD). In both cases, the atrial septal occluder (Amplatzer™ Atrial Septal Occluder Device, Abbott, Chicago USA) caused the erosion between the left atrium and the aortic root. The atrio-aortic erosion led to acute cardiac tamponade with upper venous congestion and shock. As the bleeding source remained undetectable for any imaging tools, a diagnostical sternotomy remained the only solution. The cause of the acute bleeding was discovered to be the erosion between the left atrium and the aortic root. The treatment consisted in the removal of the occluder, direct suturing of the perforated areas and the surgical closure of the remaining ASD. The patients fully recovered within the nine to fourteen days' hospital stay. Six months after surgery both patients were well and able to recover their daily routine. CONCLUSIONS The atrio-aortic erosion after percutaneous closure of atrial septal defects is a surgical emergency. The more so, since it can be complicated by the absence of specific symptoms. A key-element in the diagnosis of this rare pathology remains the medical history of the patient, which the surgeon has to consider thoroughly and launch the diagnostic sternotomy without delay
Features of stable diffuse arcs observed by means of auroral tomography
In this paper we study the spatial distribution of optical volume emission
rates and peculiarities of the luminosity intensity within weak diffuse
auroral arcs recovered by means of auroral tomography. The tomographic
images are obtained from sets of scanning multi-channel photometer data
obtained in February 1999 on the Kola Peninsula in Russia at three sites of
a chain extending 226 km along the geomagnetic meridian. The 427.8- and
557.7-nm emissions of a 15-s time resolution observed within one hour during
low geomagnetic activity are analyzed. We found that the intensity profile
of an individual arc along the geomagnetic meridian has an inverted-V-shape.
The luminosity maximum altitude decrease by 4–14 km at about 140 km distance
in the south-north direction can be observed during two or more diffuse
arcs. The parameters of the precipitating electron flux are obtained from an
integral equation, which determines the best relationship between the 427.8-nm
intensity height profile and an arbitrary particle energy spectrum. A
dimensionless function of the energy dissipation is used as the core in the
integral equation. The estimated average energy of electron flux, which
generated the isolated diffuse arc, is 1–2 keV higher in the central part of
the arc in comparison to values at its borders
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