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We consider a nonstationary problem of determination of temperature in a circular concentric cylindrical channel of infinite length with thermally insulated surfaces filled with a moving medium under the influence of inductive heating of a conductor in the form of a cylindrical helical line (helix) synchronously rotating about the axis of symmetry of the channel. Problems of this kind are encountered in the process of thermal treatment of biomaterials with the use of the pyrolysis reaction when the helical surface of an auger moving a material mixture is inductively heated by electromagnetic fields. We solve these problem by using the Laplace integral transform with respect to time, Fourier integral transform with respect to the axial coordinate, and Fourier-Bessel expansions with respect to the angular and radial coordinates. It is shown that the temperature in the channel is, as a rule, described by a linearly increasing function of time. Weak oscillations caused by the rotation of the heated helix are imposed on this component. Low-amplitude oscillations of temperature are described by double Fourier-Bessel series whose coefficients are determined via the roots of a transcendental equation containing cross products of the derivatives of Bessel and Neumann functions. These roots are numerically determined by the 'regula falsi' method. The numerical analysis reveals a substantial influence of the radius, pitch, and the angular rotational velocity of the helix, and the linear velocity of the medium in the channel on the formation of space and time characteristics of the microstructure of temperature field. In particular, we establish the conditions leading to the resonant amplification of the amplitude of quasimonochromatic oscillations of temperature in the channel. Keywords: auger reactor, auger spiral, electric heating, nonstationary temperature field, mathematical modeling, numerical analysis., Introduction The problem of improvement of the technological processes of pyrolysis processing of various types of wastes and biomasses explains the necessity of comprehensive model and experimental investigations in this [...]

A surgical procedure for the repair of damaged periodontal tissue is Guided Tissue Regeneration (GTR), which involves the use of a barrier membrane to prevent soft tissue ingrowth and create a space for slow regeneration of periodontium and bone. GTR membrane should have pores able to facilitate the diffusion of fluids, oxygen, nutrients, and bioactive substances for cell growth, but also be impermeable to epithelial cells or gingival fibroblasts, which could overpopulate the defect space and inhibit infiltration and activity of boneforming cells. In this paper, a bilayer PLGA membrane was realized by coupling the dip coating and electrospinning techniques. The rough layer of the double-sided structure was electrospun on the previously prepared smooth dip-coated membrane. A rotating drum collector at two rotating speeds was used to generate different fibers orientation. The bilayer membrane with different superimposed surfaces was successfully fabricated and characterized from a morphological, physicochemical, and the mechanical point of view. Performed analyses revealed that the membrane possesses suitable properties, especially from mechanical point of view, for its possible use as a scaffold for the GTR of periodontum. A high fiber alignment and improved mechanical properties with respect to available GTR membranes characterized the product resulting from this study. KEYWORDS biodegradable, biological applications of polymers, biomaterials, dental polymers, electrospinning, mechanical properties, 1 | INTRODUCTION The untreated periodontal disease such as chronic periodontitis can provoke loss of gingival tissue, connective tissue, alveolar bone, and periodontal ligaments and consequently the destruction of periodontium, [...]

Determination of macro- and trace elements in various biological fluids, including saliva and blood serum, is widely used for medical diagnostics and assessment of the impact of anthropogenic factors on human health. The most popular methods of spectral analysis have several disadvantages, including the need in sample preparation. As an alternative, we proposed a direct (without digestion) analysis of biofluids by arc atomic emission spectrometry using the dry residue method. The experimentally found optimal amount of the spectral buffer (0.15 mg of NaCl) and current strength (20 A) ensure a high-intensity analytical signal and a better limit of detection. The selected conditions also neutralize the effect of the saliva and serum matrix on the parameters of the arc plasma (temperature and electron concentration), which enables the use of standard aqueous solutions of element salts for plotting calibration curves. When 150 [micro]L of a whole saliva sample is applied to one end of the electrode, the limits of detection are at the level of no more than 1 [micro]g/L for Ag, Al, Cd, Cu, Fe, Mn, and Zn and several micrograms per liter for Cr, Pb, and Ti. No more than 50 [micro]L of blood serum can be applied to the electrode end face; the limits of detection, in this case, are three times higher. We assessed the accuracy of the determination of trace elements in real samples of saliva and blood serum. Additionally, a possibility of determining macroelements (Ca, Mg, P, Si) in saliva is demonstrated., Author(s): S. S. Savinov [sup.1], A. I. Drobyshev [sup.1] Author Affiliations: (1) grid.15447.33, 0000 0001 2289 6897, Institute of Chemistry, St. Petersburg State University, , 199034, St. Petersburg, Russia Trace [...]

Purpose To develop evidence-based clinical practice recommendations regarding transfusion practices and transfusion in bleeding critically ill adults. Methods A taskforce involving 15 international experts and 2 methodologists used the GRADE approach to guideline development. The taskforce addressed three main topics: transfusion support in massively and non-massively bleeding critically ill patients (transfusion ratios, blood products, and point of care testing) and the use of tranexamic acid. The panel developed and answered structured guideline questions using population, intervention, comparison, and outcomes (PICO) format. Results The taskforce generated 26 clinical practice recommendations (2 strong recommendations, 13 conditional recommendations, 11 no recommendation), and identified 10 PICOs with insufficient evidence to make a recommendation. Conclusions This clinical practice guideline provides evidence-based recommendations for the management of massively and non-massively bleeding critically ill adult patients and identifies areas where further research is needed., Author(s): Alexander P. J. Vlaar [sup.1], Joanna C. Dionne [sup.2] [sup.3] [sup.4] [sup.21], Sanne de Bruin [sup.1], Marije Wijnberge [sup.1] [sup.5], S. Jorinde Raasveld [sup.1], Frank E. H. P. van [...]