Experimental study and numerical simulation of ion cyclotron heating of a hydrogen plasma in the T-11M tokamak

Results are presented from investigations of the possibility of heating a hydrogen plasma at the fundamental harmonic of the ion cyclotron frequency in the T-11M tokamak. The fluxes of charge-exchange atoms that escape from the plasma in the radial direction and across the toroidal magnetic field (transverse neutrals) were recorded by a Lakmus neutral particle analyzer. Measurements by the analyzer show that, during an RF pulse, the ion temperature increases by approximately 50–100 eV. Such plasma parameters as the ion temperature, rotation velocity, and isotopic composition were measured by a high-resolution spectrometer. According to the data from high-resolution spectroscopy, the ion temperature increases by approximately 150 eV. Results from numerical simulations of the ion cyclotron resonance heating of a hydrogen plasma in the T-11M tokamak are also given.     

Synovial T cell hyporesponsiveness to myeloid dendritic cells is reversed by preventing PD-1/PD-L1 interactions

Introduction

The aim of this study was to investigate PD-1/PD-L1 involvement in the hyporesponsiveness of rheumatoid arthritis (RA) synovial fluid (SF) CD4 T cells upon stimulation by thymic stromal lymphopoietin (TSLP)–primed CD1c myeloid dendritic cells (mDCs).

Methods

Expression of PD-1 on naïve (Tn), central memory (Tcm) and effector memory (Tem) CD4 T cell subsets was assessed by flow cytometry. PD-L1 expression and its regulation upon TSLP stimulation of mDCs from peripheral blood (PB) and SF of RA patients were investigated by quantitative RT-PCR and flow cytometry. The involvement of PD-1/PD-L1 interactions in SF T cell hyporesponsiveness upon (TSLP-primed) mDC activation was determined by cell culture in the presence of PD-1 blocking antibodies, with or without interleukin 7 (IL-7) as a recognized suppressor of PD-1 expression.

Results

PD-1 expression was increased on CD4 T cells derived from SF compared with PB of RA patients. TSLP increased PD-L1 mRNA expression in both PB and SF mDCs. PD-L1 protein expression was increased on SF mDCs compared with PB mDCs and was associated with T cell hyporesponsiveness. Blockade of PD-1, as well as IL-7 stimulation, during cocultures of memory T cells and (TSLP-primed) mDCs from RA patients significantly recovered T cell proliferation.

Conclusion

SF T cell hyporesponsiveness upon (TSLP-primed) mDC stimulation in RA joints is partially dependent on PD-1/PD-L1 interactions, as PD-1 and PD-L1 are both highly expressed on SF T cells and mDCs, respectively, and inhibiting PD-1 availability restores T cell proliferation. The potential of IL-7 to robustly reverse this hyporesponsiveness suggests that such proinflammatory cytokines in RA joints strongly contribute to memory T cell activation.     

Decay instability of a laser pulse propagating in a transverse direction in a magnetized plasma

The decay instability of a lser pulse propagating across an external magnetic field in a subscritical plasma is investigated analytically and numerically. It is shown that, when the relaxation of the pulse is taken into account, the hydrodynamic growth rate of the decay instability is slower than that obtained earlier in the constant-amplitude pump wave approximation. The results of numerical simulations by a particle-in-cell method demonstrate that an increase in the amplitude of the parametrically excited waves is accompanied by a decrease in their group velocity; in this case, up to 85% of the laser energy is converted into the energy of the plasma particles. It is found that, under resonance conditions, the magnetic field acts to increase the energy of the accelerated ions that escape from the plasma slab through its front boundary.     

The Role of Polygalacturonase (PG) in the Ripening of Apple Fruits

Polygalacturonase (PG) activity and changes in respiratory intensity of apple fruits were investigated. The respiratory rate was decreased to a preclimacteric minimum from 30 Aug. to 20 Sept., Then increased to a climacteric peak (20–30 Sept.) and again drop down gradually with approaching the senescence stage. The PG activity was undetectable in a developing fruit until the onset climacteric phase. It rose rapidly after harvest, and reaching its highest level on 27 Oct. Just a month after the climacteric peak. The PG activity fell gradually. The amount of the fractions of pectic acid in fruits changed with the modifications of PG activity. With the ripening of fruits, the content of alcohol-soluble small molecules of pectic acids was increased from 12 to 13 5 mg/100 g of tissue, while the amount of alcohol- insoluble large molecules of pectic acids reduced from 530 to 280/100 g of tissue. PG activity would indicate the destruction of cell walls and the separation of cells. The onset of softening of fruits occurred 20 days after the rise of PG activity. It is supposed that the process of softening is directly controlled by PG activity.     

A functional-morphologic analysis of reactive changes in nerve fibers during development of collateral circulation in nerves]

After stopping the blood circulation along the femoral artery the collateral blood circulation is developing unevenly in different nerves. It depends on the architectonics of blood vessels of the zone. In time the intravenous anastomosis in the distal part of the ischiatic nerve sharply increases. It is pulsing and compressing the nerve bundles and may have a negative influence on nerve fibres. Reactive morphological changes of the axis cylinder, myelin incisions and Ranvier's constrictions are found in such a nerve. The analysis has shown that the changes noted have a character of local non-specific process accompanying physiological manifestations of parabiosis.     

Effect of the antibodies to gangliosides on the Retzius neuron electrical activity and the functional activity of sodium channels for incoming current in leech

In the present study, the effect of antibodies to gangliosides on the Retzius neurons of the leech was investigated to study the spike activity and the functional activity of the Na-channels which generate the spike. A forty-minute incubation of the Retzius neurons in a 20% solution of antiganglioside serum in a Ringer solution provoked appearance of a double spike (a spike with two parts) connected with a decrease of the speed of the activation of the tetrodotoxin (TTX)-sensitive Nachannels. The high frequency synaptic activation of the neuron (10 Hz during 10 minutes) under the plasticity exchange of the gate system of the TTX-sensitive Na-channels. As a result of this, there was a disturbance of the habituation of the Retzius neuron to the high-frequency stimulation.     

Immune links in the system organization of behaviour

The work is devoted to the research of immune mechanisms in self-control of various functional systems of homeostatic and behavioral levels. Distinction of immune mechanisms in rats with different prognostic stress-resistance is established. Immunization of rats by conjugates of various neuromediators with bovine serum albumin selectively changes the animals stress-resistance. Participation cytokines in reactions of a brain's separate neurons and their interaction with a leading neuromediator - norepinephrine is established. Individual changes of pro- and anti-inflammatory cytokines in blood serum are shown in rats with different stress-resistance. There are revealed features of morphological distinctions of immunogenic structures small intestine fabrics in animals with various behavioral activity in the "Open field" test.