The case of a large left atrial myxoma complicated by a cardioembolic cerebral infarction

With the advent of echocardiography significantly increased frequency of in vivo diagnosis of cardiac myxomas. Needs awareness of cardiologists and experts of related specialties regarding the polymorphism of clinical manifestations, morphology, complications and other features of cardiac myxomas is the key to early diagnosis and successful treatment, because it is one of the few potentially curable tumors of the heart. Although a myxoma of the heart belongs among the most studied tumors, ongoing research on etiology, morphology, histogenesis mix, and given us a clinical case indicate the need for improved knowledge about mixomas in order to improve the diagnosis and treatment of patients with cardiac tumors.С появлением эхокардиографии существенно увеличилась частота прижизненной диагностики миксом сердца. Должная осведомленность кардиологов и специалистов смежных специальностей касательно полиморфизма клинических проявлений, морфологии, осложнений и других характеристик миксомы сердца является залогом ранней диагностики и успешного лечения, поскольку это одна из немногих потенциально излечимых опухолей сердца. Хотя миксома сердца принадлежит к наиболее изученным опухолям, продолжающиеся исследования в области этиологии, морфологии, гистогенеза миксом, а также приведенный нами клинический случай указывают на необходимость совершенствования знаний о миксомах в целях улучшения диагностики и лечения пациентов с опухолями сердца

L-Asparaginase Conjugates from the Hyperthermophilic Archaea <i>Thermococcus sibiricus</i> with Improved Biocatalytic Properties

This study investigated the effect of polycationic and uncharged polymers (and oligomers) on the catalytic parameters and thermostability of L-asparaginase from Thermococcus sibiricus (TsA). This enzyme has potential applications in the food industry to decrease the formation of carcinogenic acrylamide during the processing of carbohydrate-containing products. Conjugation with the polyamines polyethylenimine and spermine (PEI and Spm) or polyethylene glycol (PEG) did not significantly affect the secondary structure of the enzyme. PEG contributes to the stabilization of the dimeric form of TsA, as shown by HPLC. Furthermore, neither polyamines nor PEG significantly affected the binding of the L-Asn substrate to TsA. The conjugates showed greater maximum activity at pH 7.5 and 85 °C, 10–50% more than for native TsA. The pH optima for both TsA-PEI and TsA-Spm conjugates were shifted to lower pH ranges from pH 10 (for the native enzyme) to pH 8.0. Additionally, the TsA-Spm conjugate exhibited the highest activity at pH 6.5–9.0 among all the samples. Furthermore, the temperature optimum for activity at pH 7.5 shifted from 90–95 °C to 80–85 °C for the conjugates. The thermal inactivation mechanism of TsA-PEG appeared to change, and no aggregation was observed in contrast to that of the native enzyme. This was visually confirmed and supported by the analysis of the CD spectra, which remained almost unchanged after heating the conjugate solution. These results suggest that TsA-PEG may be a more stable form of TsA, making it a potentially more suitable option for industrial use

Near field of Hertzian dipole excited by impulse current

The angle dependence of near field radiated of Hertzian dipole excited by transient current is investigated. The more precise approximation in the solution for near field of the dipole is obtained in time domain by means of vector potential technique. As an example, the quickly decreasing excitation current case is considered

Analysis of fields reflected from model of human body surface using artificial neural network in time domain

The problem of determination of thickness a layer of layered medium by impulse irradiation is considered. The impulse fields reflected from the model of human body surface are analyzed by artificial neural network in time domain directly. The normal incidence of plane wave with Gaussian time form on the layered medium with losses is considered. The reflected electromagnetic field is obtained by FDTD method. Initial data for neural network analysis are the values of amplitude of electrical component of reflected field. As an example, the network is trained to determine the thickness of one of the layers of the medium. The stability of the determination in presence of interferences, experimental errors and instabilities of medium parameters is investigated by numerical simulation

Transient radiation from the open end of circular waveguide

The transient radiation from the open end of a circular waveguide is considered by simple analytical and direct numerical methods. The radiation of short pulse from the aperture is provided by calculation of special time form of field by means of modal basis method that permits to solve the problem of pulse evolution for positive and negative time with the use of Laplace transform. The radiation of the short pulse is calculated in Kirchhoff approximation and simulated by FDTD method. The frequency characteristics of the radiated field are considered