Metal Ir coatings on endocardial electrode tips, obtained by MOCVD

The present work demonstrates the application of the Metal-Organic Chemical Vapor Deposition technique to fabricate metal iridium coatings onto the pole tips of endocardial electrodes. Using iridium (III) acetylacetonate as volatile precursor, the target coatings were successfully applied to the working surface of cathodes and anodes of pacemaker electrodes in the flow type reactor in hydrogen atmosphere at deposition temperature of 550°C. The coating samples were characterized by means of XRD, SEM, Raman- and XPS-spectroscopies. The formation of non-textured coatings with fractal-like morphology and 7-24 nm crystallite size has been realized. The electrochemical properties of the coatings were investigated by cyclic voltammetry and electrochemical impedance spectroscopy. The charge storage capacity values of the electrochemically activated samples were 17.0-115 mC·cm–2 and 14.4-76.5 mC·cm–2 for measurements carried out in 0.1M sulfuric acid and in phosphate buffer saline solutions, respectively. A comparison of some characteristics of the samples obtained with commercially available cathode of pacemaker electrodes is also presented

The Semantic and Etymological Peculiarities of the Verbs of Blame

The article deals with the semantic analysis of the verbs of blame (brawl, castigate, condemn, curse, damn, lecture, rate, rebuke, reprehend, reprimand, reproach, reprobate, reprove, row, strafe, swear, trounce) in the perspective of semantics, as well as etymology. In accordance with the dominant cross-disciplinary approach to the linguistic research, the semantics of the verbs under study is analyzed in correlation with the relevant extra-linguistic data. It reveals the necessity of using some data of cognitive linguistics together with etymological methods of semantic analysis. The complex of cognitive and etymological methods helps to determine the functioning of the verbs in different kinds of discourse, and to find the closest equivalent in the Russian language

Tickborne Pathogen Detection, Western Siberia, Russia

Ixodes and Dermacentor ticks harbor Borrelia, Anaplasma/Ehrlichia, Bartonella, and Babesia species

Effect of Amino Group Charge on the Photooxidation Kinetics of Aromatic Amino Acids

The kinetics of the photooxidation of aromatic amino acids histidine (His), tyrosine (Tyr), and tryptophan (Trp) by 3,3′,4,4′-benzophenonetetracarboxylic acid (TCBP) has been investigated in aqueous solutions using time-resolved laser flash photolysis and time-resolved chemically induced dynamic nuclear polarization. The pH dependence of quenching rate constants is measured within a large pH range. The chemical reactivities of free His, Trp, and Tyr and of their acetylated derivatives, <i>N</i>-AcHis, <i>N</i>-AcTyr, and <i>N</i>-AcTrp, toward TCBP triplets are compared to reveal the influence of amino group charge on the oxidation of aromatic amino acids. The bimolecular rate constants of quenching reactions between the triplet-excited TCBP in the fully deprotonated state and tryptophan, histidine, and tyrosine with a positively charged amino group are <i>k</i>_q = 2.2 × 10⁹ M^–1 s^–1 (4.9 < pH < 9.4), <i>k</i>_q = 1.6 × 10⁹ M^–1 s^–1 (6.0 < pH < 9.2), and <i>k</i>_q = 1.5 × 10⁹ M^–1 s^–1 (4.9 < pH < 9.0), respectively. Tryptophan, histidine, and tyrosine with a neutral amino group quench the TCBP triplets with the corresponding rate constants <i>k</i>_q = 8.0 × 10⁸ M^–1 s^–1 (pH > 9.4), <i>k</i>_q = 3.0 × 10⁸ M^–1 s^–1 (pH > 9.2), and <i>k</i>_q = (4.0–10.0) × 10⁸ M^–1 s^–1 (9.0 < pH < 10.1) that are close to those for the N-acetylated derivatives. Thus, it has been established that the presence of charged amino group changes oxidation rates by a significant factor; i.e., His with a positively charged amino group quenches the TCBP triplets 5 times more effectively than <i>N</i>-AcHis and His with a neutral amino group. The efficiency of quenching reaction between the TCBP triplets and Tyr and Trp with a positively charged amino group is about 3 times as high as that of both Tyr and Trp with a neutral amino group, <i>N</i>-AcTyr and <i>N</i>-AcTrp

PCR Detection of Borrelia burgdorferi Sensu Lato, Tick-Borne Encephalitis Virus, and the Human Granulocytic Ehrlichiosis Agent in Ixodes persulcatus Ticks from Western Siberia, Russia

PCR assays were used to test adult Ixodes persulcatus ticks from Western Siberia, Russia, for Borrelia burgdorferi sensu lato, tick-borne encephalitis virus (TBEV), and the human granulocytic ehrlichiosis (HGE) agent. Of the 150 ticks that were studied, 38% were infected with B. burgdorferi, 46% were infected with TBEV, and 8% were infected with the HGE agent. These three pathogens were distributed in the ticks independently of one another

Biological Studies of New Implant Materials Based on Carbon and Polymer Carriers with Film Heterostructures Containing Noble Metals

This paper presents pioneering results on the evaluation of noble metal film hetero-structures to improve some functional characteristics of carbon-based implant materials: carbon-composite material (CCM) and carbon-fiber-reinforced polyetheretherketone (CFR-PEEK). Metal-organic chemical vapor deposition (MOCVD) was successfully applied to the deposition of Ir, Pt, and PtIr films on these carriers. A noble metal layer as thin as 1 µm provided clear X-ray imaging of 1–2.5 mm thick CFR-PEEK samples. The coated and pristine CCM and CFR-PEEK samples were further surface-modified with Au and Ag nanoparticles (NPs) through MOCVD and physical vapor deposition (PVD) processes, respectively. The composition and microstructural features, the NPs sizes, and surface concentrations were determined. In vitro biological studies included tests for cytotoxicity and antibacterial properties. A series of samples were selected for subcutaneous implantation in rats (up to 3 months) and histological studies. The bimetallic PtIr-based heterostructures showed no cytotoxicity in vitro, but were less biocompatible due to a dense two-layered fibrous capsule. AuNP heterostructures on CFR-PEEK promoted cell proliferation in vitro and exhibited a strong inhibition of bacterial growth (p < 0.05) and high in vitro biocompatibility, especially Au/Ir structures. AgNP heterostructures showed a more pronounced antibacterial effect, while their in vivo biocompatibility was better than that of the pristine CFR-PEEK, but worse than that of AuNP heterostructures

Application of Biocompatible Noble Metal Film Materials to Medical Implants: TiNi Surface Modification

Recently, film materials based on the combination of noble metals have showed promising results for surface modification of medical implants, allowing both to improve biocompatibility and to acquire the increased antibacterial effect. An important challenge here is to combine the developed coating morphology, which is favorable for biological response, with a high protective function, which, on the contrary, requires a compact coating microstructure. In this work, we aimed to solve this problem with respect to the TiNi implant material. We have tested two types of compact thin sublayers: Iridium (Ir’), formed by metal-organic chemical vapor deposition (MOCVD), and gold (Au), formed by physical vapor deposition (PVD). Subsequently these sublayers were coated with a developed-columnar-iridium (Ir) by MOCVD. Features of the microstructure, chemical and phase composition of all these film materials were studied using powder X-ray diffraction (XRD), scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). The changes in the characteristics of TiNi martensitic transformation due to MOCVD experiments were also studied by differential scanning calorimetry (DSC). The biocompatibility of Ir’/TiNi, Au/TiNi, Ir/Ir’/TiNi, Ir/Au/TiNi samples was assessed by cytoxicity testing (Man-1 cells) and measuring of nickel content in the biological extracts. The application of both sublayers effectively reduces the release of nickel, which was previously shown for Ir/TiNi samples. This prevents the toxic effect. Note that the Ir’ sublayer better protects against nickel release, while the Au sublayer promotes cell proliferation