Dynamic Inversion for Nonaffine-in-Control Systems via Time-Scale Separation. Part I

This paper presents a new method for approximate dynamic inversion of nonaffine-in-control systems via time-scale separation. The control signal is sought as a solution of the “fast” dynamics and is shown to asymptotically stabilize the original nonaffine system. Sufficient conditions are formulated, which satisfy the assumptions of the Tikhonov theorem in the theory of singular perturbations. Several examples illustrate the theoretical results.      

Actions and Roles of FSH in Germinative Cells

Follicle stimulating hormone (FSH) is produced by the pituitary gland in a coordinated hypothalamic–pituitary–gonadal (HPG) axis event, plays important roles in reproduction and germ cell development during different phases of reproductive development (fetal, neonatal, puberty, and adult life), and is consequently essential for fertility. FSH is a heterodimeric glycoprotein hormone of two dissociable subunits, α and β. The FSH β-subunit (FSHβ) function starts upon coupling to its specific receptor: follicle-stimulating hormone receptor (FSHR). FSHRs are localized mainly on the surface of target cells on the testis and ovary (granulosa and Sertoli cells) and have recently been found in testicular stem cells and extra-gonadal tissue. Several reproduction disorders are associated with absent or low FSH secretion, with mutation of the FSH β-subunit or the FSH receptor, and/or its signaling pathways. However, the influence of FSH on germ cells is still poorly understood; some studies have suggested that this hormone also plays a determinant role in the self-renewal of germinative cells and acts to increase undifferentiated spermatogonia proliferation. In addition, in vitro, together with other factors, it assists the process of differentiation of primordial germ cells (PGCLCs) into gametes (oocyte-like and SSCLCs). In this review, we describe relevant research on the influence of FSH on spermatogenesis and folliculogenesis, mainly in the germ cell of humans and other species. The possible roles of FSH in germ cell generation in vitro are also presented.     

The Effect of Low-Energy Laser-Driven Ultrashort Pulsed Electron Beam Irradiation on Erythropoiesis and Oxidative Stress in Rats

Anemia is a commonly observed consequence of whole-body exposure to a dose of X-ray or gamma irradiation of the order of the mean lethal dose in mammals, and it is an important factor for the determination of the survival of animals. The aim of this study was to unravel the effect of laser-driven ultrashort pulsed electron beam (UPEB) irradiation on the process of erythropoiesis and the redox state in the organism. Wistar rats were exposed to laser-driven UPEB irradiation, after which the level of oxidative stress and the activities of different antioxidant enzymes, as well as blood smears, bone marrow imprints and sections, erythroblastic islets, hemoglobin and hematocrit, hepatic iron, DNA, and erythropoietin levels, were assessed on the 1st, 3rd, 7th, 14th, and 28th days after irradiation. Despite the fact that laser-driven UPEB irradiation requires quite low doses and repetition rates to achieve the LD₅₀ in rats, our findings suggest that whole-body exposure with this new type of irradiation causes relatively mild anemia in rats, with subsequent fast recovery up to the 28th day. Moreover, this novel type of irradiation causes highly intense processes of oxidative stress, which, despite being relatively extinguished, did not reach the physiologically stable level even at the 28th day after irradiation due to the violations in the antioxidant system of the organism.     

Mobility study of amorphous polymers by high-resolution NMR at solid-state

Summary Mobility of amorphous polymers such as poly(vinyl chloride) (PVC), atactic polypropylene (PPA) and ethylene-propylene-diene terpolymer (EPDM) were studied by proton spin-lattice relaxation time (T₁ H), proton spin-lattice relaxation time in the rotating frame (T₁ ^H ), and dipolar dephasing pulse sequence. The data are discussed in terms of mobility and by the distribution of configurational sequences.     

Carbon nanotube/silica composites obtained by sol-gel and high-pressure techniques

The successful incorporation of functionalized single-walled carbon nanotubes (f-SWCNTs) into a silica matrix prepared by the sol-gel method is reported herein. SWCNTs produced through catalytic chemical-vapor deposition (CCVD) have been purified and functionalized with sulfuric, nitric and hydrochloric acids to ensure a good dispersion in an aqueous solution. The nanotube composites are prepared using three concentrations of f-SWCNTs (0.025, 0.050 and 0.075?wt%.) in a silica matrix, resulting in translucent monoliths after gelation. Dense, crack-free and hard compacts are obtained by high-pressure processing at 7.7?GPa and room temperature. Compared to the pure silica compact, compacts containing 0.025 and 0.050?wt% f-SWCNTs show an increased toughness of about 54% and 69%, respectively. The influence of f-SWCNTs on some microstructural aspects of the silica matrix has been studied using nitrogen adsorption/desorption isotherms. Raman spectroscopy has been applied to analyze the effect of the silica matrix and high-pressure compaction on the f-SWCNTs incorporated into the silica matrix. These measurements showed that f-SWCNTs remained in the silica matrix under pressure, suggesting an important interaction with the matrix.     

Collision Avoidance Based on Line-of-Sight Angle

This paper focuses on the problem of collision avoidance for Unmanned Aerial Vehicles (UAVs). The dynamics of the UAV are modeled as a Dubins vehicle flying at constant altitude. The angular velocity is used as control input in order to avert a possible collision with a single obstacle, while the speed is left as an extra degree of freedom to achieve some temporal requirements. The proposed control algorithm uses only the line-of-sight angle as feedback: in this sense, the main contribution of this paper is providing a solution to the collision avoidance problem that can be used in situations where it is not possible to measure data such as position and velocity of the obstacle. A theoretical analysis of the result is provided, followed by simulation results that validate the efficacy of the control strategy.     

Artemisia dracunculus L. essential oil phytochemical components trigger the activity of cellular antioxidant enzymes

Investigation of dietary biologically active phytochemicals is of interest due to the availability, low cost, and low rate of side effects of these substances. The main objective of this work was to investigate the influence of the essential oil (EO) extracted from the aerial parts of Artemisia dracunculus on the antioxidant capacity of cells as this plant is one of the most available and widely used as spice and in folk medicine. For this, BV-2 microglial wild type (WT) and acyl-CoA oxidase type 1 (ACOX1) deficient cells (Acox1^−/−) were used. Acox1^−/− cells were applied as the model of cellular oxidative damage. The main component of EO of A. dracunculus was estragole, which was reaching 84.9% in plants cultivated at high altitude Armenian landscape. IC₅₀ value of EO in 1,1-diphenyl-2-picrylhydrazyl assay was 94.2 µg/ml. Sub-cytotoxic concentration in the 3-(4, 5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide test for both BV-2 WT and Acox1^−/− cell lines was 5.10⁻¹ µg/ml. Seventy-two-hours treatment with EO leads to the increased viability (up to 12% in WT and up to 14% -in BV-2 Acox1^−/−cells). The 48-hr treatment increased the ACOX1 activity up to 70% in WT cells. Catalase and superoxide dismutase activities of both cell lines increased following the 24–48-hr treatment. These results indicate that A. dracunculus EO can be considered as a potential protective agent useful in preventive medicine.     

Kunitz-Type Peptides from Sea Anemones Protect Neuronal Cells against Parkinson’s Disease Inductors via Inhibition of ROS Production and ATP-Induced P2X7 Receptor Activation

Parkinson’s disease (PD) is a socially significant disease, during the development of which oxidative stress and inflammation play a significant role. Here, we studied the neuroprotective effects of four Kunitz-type peptides from Heteractis crispa and Heteractis magnifica sea anemones against PD inductors. The peptide HCIQ1c9, which was obtained for the first time, inhibited trypsin less than other peptides due to unfavorable interactions of Arg17 with Lys43 in the enzyme. Its activity was reduced by up to 70% over the temperature range of 60–100 °C, while HCIQ2c1, HCIQ4c7, and HMIQ3c1 retained their conformation and stayed active up to 90–100 °C. All studied peptides inhibited paraquat- and rotenone-induced intracellular ROS formation, in particular NO, and scavenged free radicals outside the cells. The peptides did not modulate the TRPV1 channels but they affected the P2X7R, both of which are considered therapeutic targets in Parkinson’s disease. HMIQ3c1 and HCIQ4c7 almost completely inhibited the ATP-induced uptake of YO-PRO-1 dye in Neuro-2a cells through P2X7 ion channels and significantly reduced the stable calcium response in these cells. The complex formation of the peptides with the P2X7R extracellular domain was determined via SPR analysis. Thus, these peptides may be considered promising compounds to protect neuronal cells against PD inductors, which act as ROS production inhibitors and partially act as ATP-induced P2X7R activation inhibitors.