Plasma Reflectarrays

This paper investigates the design of four different configurations of plasma reflectarrays. The results provide insight into different radiation characteristics of plasma reflectarrays. The proposed unit cell consists of a cubic glass box filled with argon gas energized with applied AC voltage. The reflectarray reflection coefficient phase variation is achieved by varying the plasma frequency of the energized gas. Four plasma reflectarrays for satellite applications at 12 GHz are proposed (centre feed centre beam, centre feed offset beam, offset feed centre beam, and finally, offset feed offset beam). The finite integration technique is used to analyse the plasma reflectarray.     

Plasma membrane microdomains

Several lines of evidence indicate that the lipids in the plasma membrane of animal cells are inhomogeneously distributed, and that various types of specialized lipid domains play an important role in many biological processes. The characteristics of these domains, such as size, composition and dynamics, are currently under active investigation. It appears that there are many different types of membrane domains in the plasma membrane, and perhaps the entire membrane should be viewed as a mosaic of microdomains.     

Plasma relativistic microwave electronics

The principles of plasma relativistic microwave electronics based on the stimulated Cherenkov emission of electromagnetic waves during the interaction of a relativistic electron beam with a plasma are formulated. A theory of relativistic Cherenkov plasma microwave oscillators and amplifiers is developed, and model experimental devices are elaborated and investigated. The emission mechanisms are studied theoretically. The efficiencies and frequency spectra of relativistic Cherenkov plasma microwave oscillators and ampli-fiers are calculated. The theoretical predictions are confirmed by the experimental data: the power of the devices attains 500 MW, the microwave frequency can be continuously tuned over a wide band with an upper-to-lower boundary frequency ratio of 7 (from 4 to 28 GHz), and the emission frequency bandwidth can be varied from several percent to 100 percent. These microwave sources have no analogs in vacuum microwave electronics.     

High-Density Helicon Plasma Source for Linear Plasma Generators

Plasma Physics Reports - Results of experiments on a linear facility with a helicon plasma source operating at a frequency of 13.56 MHz and a power of up to 15 kW are reported. In the experiments,...     

Plasma protein fractionation

The fractionation of blood plasma yields a number of therapeutic proteins which together constitute a billion dollar world-wide market. Conventional plasma fractionation procedures are being replaced by more sophisticated chromatographic techniques. The application of genetic engineering and these new downstream processing techniques is likely to lead to improved products of higher purity and stability, with less likelihood of contamination by viruses and at lower cost per therapeutic dose.     

Plasma equilibrium with barriers

The recently proposed concept of the transport barrier formation in a tokamak plasma as a bifurcation of the equilibrium state with a change in the toroidal magnetic field over the entire plasma column, including the plasma edge, is analyzed. The analysis is performed in the cylindrical approximation. It is shown that, in the framework of the discussed concept, all of the equilibrium solutions are continuous functions of the parameters involved, bifurcations are absent, and the result is determined by the model assumptions that are necessary in order to make the task self-contained. Removing even part of these restrictive assumptions can substantially change the result. Under typical conditions, the effect of the plasma rotation on the plasma equilibrium is negligibly small. Besides, from the viewpoint of the formal analysis of the force balance, the rotation does not facilitate but, in contrast, hampers the formation of a positive pressure jump.     

离心式机械单采血浆管路、贮存袋的研究

目的：研究单采血浆中两种耗材－管路和贮存袋，材料和方法：以压力监测器接头（DPM）、导管流量和贮存袋耐寒性的研究关键。并与国内外同类产品或材料作比较，结果：DPM必须具有适宜的透气性（感应时间≤2s）、阻血性（能耐受40Kpa,40s），滤除率（0.5um粒子，≥90％），导管流量的准确性（与机器设定值误差＜5％），稳定性（采集过程中流量误差＜5％）可通过控制导管内径（3.08-3.24mm)和选择弹性PVC材料来解决，贮存袋选用耐寒PVC料。扫描电镜证实韧性断裂。结论：研制成的管路和PCS^2机器适配能取代进口同类产品，研制的贮存袋能低温保存血浆，破损率小于2‰。     

Studying How Plasma Jets are Generated in a Plasma Focus

Plasma Physics Reports - Plasma bunches with the characteristic size of approximately 1 mm and electron density larger than 1019 cm–3 are registered by the laser sounding methods on a...     

质膜钙离子ATP酶

钙离子(Ca2+)是重要的第二信使,通过与效应蛋白的结合和解离,以及在不同细胞器之间的穿梭运动而精确调控细胞活动,参与多种重要生命过程。细胞内具有精确调节Ca2+时空分布的调控系统。在静息状态下,细胞内的游离Ca2+浓度约为100 nmol/L;而当细胞受到信号刺激后,胞内的Ca2+浓度可上升至1000 nmol/L甚至更高。细胞中存在多种跨膜运送Ca2+的膜蛋白,以精确调节Ca2+浓度的时空动态变化,其中,细胞质膜上的多种Ca2+通道(包括电压门控通道、受体门控通道、储存控制通道等),以及内质网/肌质网和线粒体等胞内"钙库"膜上的雷诺丁受体、三磷酸肌醇受体等膜蛋白复合物,均可提升胞内Ca2+浓度,而细胞质膜上的钠钙交换体、质膜Ca2+-ATP酶、"钙库"膜上的内质网Ca2+-ATP酶、线粒体Ca2+单向转运体等,可将Ca2+浓度降低至静息态水平。质膜钙ATP酶是向细胞外运送Ca2+的关键膜蛋白,本文将对其结构、功能及其酶活性的调控机制做一简要综述。     

Plasma fibronectin in hemoblastosis

Fibronectin (FN) is a glycoprotein whose plasma concentrations are reduced in many pathological conditions. In patients with hemoblastosis plasma FN was correlated with some clinical and biological parameters (stage of the disease, hepatosplenomegaly, infections and DIC), in order to assess its value as a tumor marker. The results suggest a poor relationship between FN levels and the course of the disease. However, the behaviour of the protein in relation with treatment was dynamic.     

Supernonlinear Waves in Plasma

A new class of nonlinear waves in plasma??supernonlinear waves (SNWs) characterized by the nontrivial topology of their phase portraits??has been revealed. The topological classification of such waves is given, and suitable notation for them is proposed. It is demonstrated using several examples that SNWs can exist in the form of plasma waves of different physical nature, e.g., electrostatic (ion-acoustic) and MHD (Alfvén) waves. It is shown that a necessary condition for the existence of SNWs is the presence of at least three different charged plasma components (electrons, positrons, ions, dust grains, etc.). As the number of plasma components increases, the topology of the SNW phase portrait becomes more complicated. Typical indications of SNWs are given, which make is possible to easily reveal such waves experimentally.     

Skin Effects in a Dusty Plasma

A multifluid MHD model is applied to study the magnetic field dynamics in a dusty plasma. The motion of plasma electrons and ions is treated against the background of arbitrarily charged, immobile dust grains. When the dust density gradient is nonzero and when the inertia of the ions and electrons and the dissipation from their collisions with dust grains are neglected, we are dealing with a nonlinear convective penetration of the magnetic field into the plasma. When the dust density is uniform, the magnetic field dynamics is described by the nonlinear diffusion equations. The limiting cases of diffusion equations are analyzed for different parameter values of the problem (i.e., different rates of the collisions of ions and electrons with the dust grains and different ratios between the concentrations of the plasma components), and some of their solutions (including self-similar ones) are found. The results obtained can also be useful for research in solid-state physics, in which case the electrons and holes in a semiconductor may be analogues of plasma electrons and ions and the role of dust grains may be played by the crystal lattice and impurity atoms.     

Effect of Dielectric and Liquid on Plasma Sterilization Using Dielectric Barrier Discharge Plasma

Plasma sterilization offers a faster, less toxic and versatile alternative to conventional sterilization methods. Using a relatively small, low temperature, atmospheric, dielectric barrier discharge surface plasma generator, we achieved ≥6 log reduction in concentration of vegetative bacterial and yeast cells within 4 minutes and ≥6 log reduction of Geobacillus stearothermophilus spores within 20 minutes. Plasma sterilization is influenced by a wide variety of factors. Two factors studied in this particular paper are the effect of using different dielectric substrates and the significance of the amount of liquid on the dielectric surface. Of the two dielectric substrates tested (FR4 and semi-ceramic (SC)), it is noted that the FR4 is more efficient in terms of time taken for complete inactivation. FR4 is more efficient at generating plasma as shown by the intensity of spectral peaks, amount of ozone generated, the power used and the speed of killing vegetative cells. The surface temperature during plasma generation is also higher in the case of FR4. An inoculated FR4 or SC device produces less ozone than the respective clean devices. Temperature studies show that the surface temperatures reached during plasma generation are in the range of 30°C–66°C (for FR4) and 20°C–49°C (for SC). Surface temperatures during plasma generation of inoculated devices are lower than the corresponding temperatures of clean devices. pH studies indicate a slight reduction in pH value due to plasma generation, which implies that while temperature and acidification may play a minor role in DBD plasma sterilization, the presence of the liquid on the dielectric surface hampers sterilization and as the liquid evaporates, sterilization improves.     

High-Power X-Ray Line Radiation of the Plasma Produced in a Collision of High-Energy Plasma Flows

Results are presented from experimental studies of a pulsed source of soft X-ray (SXR) emission with photon energies in the range of 0.4–1 keV and an output energy of 2–10 kJ. SXR pulses with a duration of 10–15 μs were generated in collisions of two plasma flows propagating toward one another in a longitudinal magnetic field. The plasma flows with velocities of (2–4) × 10⁷ cm/s and energy contents of 70–100 kJ were produced by two electrodynamic coaxial accelerators with pulsed gas injection. Nitrogen and neon, as well as their mixtures with deuterium, were used as working gases. The diagnostic equipment is described, and the experimental results obtained under different operating conditions are discussed. In particular, X-ray spectroscopy was used to study the high-temperature plasma produced in a collision of two plasma flows. The observed intensities of spectral lines are compared with the results of detailed kinetic calculations performed in a steady-state approximation. The calculations of the nitrogen and neon kinetics have shown that the electron temperature of a nitrogen plasma can be most conveniently determined from the intensity ratio of the resonance lines of He- and H-like nitrogen ions, while that of a neon plasma, from the intensity ratio between the resonance line of He-like Ne IX ions and the 3p?2s line of Li-like Ne VIII ions. In the experiments with plasma flows containing nitrogen ions, the electron temperature was found to be ≈120 eV, whereas in the experiments with plasma flows containing neon ions, it was 160–170 eV.     

Plasma enzymes inactivating alkaloids

It was shown that rat blood plasma contains two enzymes that inactivate alkaloids by transforming them into N-oxides. Both enzymes are hemoproteins: one of them consists of three different polypeptides with Mr of 63, 35 and 12 kD, while the other one is a single polypeptide with Mr of 73 kD. Both enzymes exhibit cooperative properties.     

Moment Aberrations of Magnetoelectrostatic Plasma Lenses

The moment and geometric aberrations of magnetoelectrostatic plasma lenses are studied by computer modeling. Conditions are determined such that these aberrations can be made substantially lower, in which case the cross-sectional area of a focused beam can be reduced by a factor of 10⁵ and the ion current density at the focus of a lens can amount to 10³ A/cm².     

Stability of a Planar Plasma Crystal

Plasma Physics Reports - The stability of a planar plasma crystal in an external confining force field is investigated. Particles are assumed to be located in the plasma with Maxwellian electrons...     

Plasma membrane-microfilament interaction in animal cells

Microfilament interactions with the plasma membranes of animal cells appear to vary with cell type and localization. In the erythrocyte, actin oligomers are associated with the membrane via spectrin and ankyrin. The ends of stress fibers in cultured cells, such as fibroblasts, are attached to the plasma membrane at focal adhesion sites and may involve the protein vinculin as a linking protein. In intestinal brush border microvilli a 110,000 dalton protein links the microfilament bundles to sites on the microvillus. A transmembrane complex containing actin stably associated with a cell surface glycoprotein can be isolated from ascites tumor cell microvilli and can be obtained still associated with microfilaments by gentle extraction and gradient centrifugation of the microvilli. These varied interaction mechanisms are believed to be needed to satisfy the different structural and dynamic requirements of the particular systems.     

Depletion of Plasma Albumin for Proteomic Analysis of Bothrops jararaca Snake Plasma

The proteomic analysis of plasma samples represents a challenge as a result of the presence of highly abundant proteins such as albumin. To enable the detection of biomarkers, which are commonly low-abundance proteins, in complex blood fluids, it is necessary to remove high-abundance proteins efficiently. Moreover, there is a range of about 10 orders of magnitude for the abundance of different protein species in serum. Here, we describe for the first time a study of reptilian albumin depletion using resins usually used in mammalian plasma depletion procedures. We performed the depletion of albumin from Bothrops jaraca plasma using the HiTrap Blue high-performance column (GE Healthcare Life Sciences, Piscataway, NJ, USA) and the kit Albumin & IgG Depletion SpinTrap column (GE Healthcare Life Sciences). In addition, proteomic approaches were used to analyze reptilian plasma. Our results showed that B. jararaca albumin bound to both columns, but those interactions were not enough to remove a large amount of albumin to reach an enrichment of low-abundance proteins. Although the depletion techniques used in this work were not the best to remove B. jararaca plasma albumin, our present work highlights the similarity between B. jararaca and mammalian albumin, contributing to the knowledge of comparative hemostatic proteins.     

Plasma membrane helps autophagosomes grow

The membrane origin of autophagosomes has long been a mystery and it may involve multiple sources. In this punctum, we discuss our recent finding that the plasma membrane contributes to the formation of pre-autophagic structures via clathrin-mediated endocytosis. Our study suggests that Atg16L1 interacts with clathrin heavy-chain/AP2 and is also localized on vesicles (positive for clathrin or cholera toxin B) close to the plasma membrane. Live-cell imaging studies revealed that the plasma membrane contributes to Atg16L1-positive structures and that this process and autophagosome formation are impaired by knockdowns of genes regulating clathrin-mediated endocytosis.