Effect of Convalescent Plasma Therapy on Mortality and Viral Load in Severely Ill Patients with COVID-19.

The use of convalescent plasma (CP) appeared to be a promising, easily available and safe way of treatment of severe COVID-19 at the onset of the pandemic in early 2020. Conducted in 2020 and 2021, our study of 52 severely to critically ill COVID-19 patients who received CP plasma as a treatment and of 97 controls found no difference in 30-day or 90-day mortality rates. A significant viral load drop in most patients (4.7 log10 [p<0.001] copies/ml) was observed following CP administration. Retrospective analysis of selected inflammatory markers and immunoglobulins showed higher C-reactive protein levels among the study group, and their decrease on Day 7.

Influence of Strain Rate on Plastic Deformation of the Flange in Steel Road Barrier.

This study investigates the influence of strain rate on plastic deformation developed in the flange of a steel road barrier. This effect can be investigated by the use of the uniaxial tensile test. It was found that the strain rate increases yield as well as ultimate strength and gently drops down the elongation at break. Moreover, the accelerated strain rate is connected with matrix heating and increasing the Taylor-Quinney coefficient. Despite the valuable matrix heating and the higher Taylor-Quinney coefficient at the higher strain rates, samples necking is initiated earlier and dislocation density is higher. Flange grains become preferentially aligned along the direction of uniaxial stress, especially at the higher plastic strains. Finally, surface Zn protective layer delamination is initiated quite early beyond the yielding. It is considered that the cracks are due to the different response of the Zn allayer and underlying steel matrix on the plastic straining. Increasing strain rate attenuates the degree of Zn layer delamination.

An Application of a Magnetic Impulse for the Bending of Metal Sheet Specimens.

Currently, classical methods for the creation of various shapes and bending angles of metal sheet parts are applied. They are represented by the so-called all-metal forming tools. Non-standard methods, which in some cases exceed conventional technical solutions, are used in the practice to a minor extent. This is an area of interest from the point of view of ecology, because the shaping process performed in this way does not burden the environment in any considerable way. The knowledge presented in this work is obtained based on experiments in laboratory conditions. The list of literature contains mainly works from the recent period. The research represents a contribution to the great mosaic of magnetism. The aim of the current paper is to also verify the possibilities of the suitability of a special tool in the formation of metal sheet specimens using the application of the so-called forming with a free core. Additional benefits of the experimental work and their results are anticipated. The contribution is complemented by detailed calculations and diagrams. The practical contribution and research is that the device used for forming has been successfully tested. It turns out that the presented method is suitable for further development. The method has proven that is it suitable for industrial applications where simple shapes are produced.

Investigation of Forging Metal Specimens of Different Relative Reductions Using Ultrasonic Waves.

Forgings produced in industry are an irreplaceable basis for subsequent elaborating on machine tools. The quality of the semi-finished product produced by forging is a necessary prerequisite for ensuring the final quality of the final product because the forging can produce some defects. The presented paper is aimed at investigation of selected characteristics of forging steel specimens for various levels of their relative reduction. Ultrasound testing belongs to methods for investigation of structure changes, including defects. Experimental investigation, using both the attenuation and velocity measurements, verify that the reduction of specimens' material can have an effect on the propagation of ultrasound waves passing through the specimen body. The procedure of steel samples forging corresponds accordingly to the process of their hardening. The increase of toughness after relative reduction of forging in the range of 10-50% is with highest probability caused by the strength matrices development due to the relatively important deformation hardening. It is evident that the deformation hardening is almost the same after every 10% addition of relative reduction. Experiments are supplemented by Barkhausen noise detection and metallographic characteristics of the samples. While differences between the Barkhausen noise values are in principle relatively small and significant differences are only in the values of the position of the envelope, there is maximum coincidence with ultrasonic investigation.

Early postdenervation depolarization develops faster at endplates of hibernating golden hamsters where spontaneous quantal and non-quantal acetylcholine release is very small.

The hyperpolarization produced by the application of curare to the postsynaptic membrane of the diaphragm neuromuscular synapse (H-effect) is a measure of non-quantal release (NQR) of acetylcholine (ACh) from the motor nerve ending. In mouse diaphragm, H-effect was 9.3 mV, significantly lower in awake hamsters (7.1 mV) and very small (1.1 mV) in hibernating hamsters. Also, the initial resting membrane potential (RMP) after dissection was highest in mouse (81.5 mV, inside negative), significantly smaller in awake hamsters (77.9 mV) and lowest in hibernating hamsters (75.1 mV). The early postdenervation depolarization of muscle fiber RMP to about 66-68 mV developed with half-decay time (T1/2) of 120 min in mouse, more rapidly in active hamsters (T1/2=60 min) and even faster in hibernating hamsters (T1/2=25 min) muscles. This reciprocal correlation between the H-effect and the rate of early depolarization indicates that non-quantal release is important for maintaining the resting membrane potential [Vyskocil, F. 2003. Early postdenervation depolarization is controlled by acetylcholine and glutamate via nitric oxide regulation of the chloride transporter. Neurochem. Res. 28, 575-585]. The amplitude of H-effect in mouse and hamster was proportional to the spontaneous quantal release. The frequency of miniature endplate potentials was highest in mouse (1.6 s-1), much smaller in awake hamsters (0.51 s-1) and very small in hibernating hamsters (0.08 s-1). This is in accordance with the idea that non-quantal release depends on the number of vesicles fused with the presynaptic membrane during quantal release [Edwards et al., 1985; Ferguson, S.M., Savchenko, V., Apparsundaram, S., Zwick, M., Wright J., Heilman, C.J., Yi, H., Levey, A.I., Blakely R.D. Vesicular localization and activity-dependent trafficking of presynaptic choline transporters. J. Neurosci. 23 (2003) 9697-9709].