N2O Decomposition and Formation of NO x Species on Fe–ferrierite. Effect of NO and CO Addition on the Decomposition and the Role of Surface Species

The adsorption of CO and CO₂ on Pt supported on ZrO₂ and Ce/La-promoted ZrO₂ was studied using DRIFTS. The presence of both La and Ce resulted in a decrease in the adsorption of CO at room temperature after reduction at 350 °C. The reduction in the CO adsorption is ascribed to an increase in the support reducibility when La and Ce are both present. Reduction at 350 °C leads to the formation of oxygen defects in the dual promoted support which have been probed using DRIFTS to monitor CO₂ dissociation. Hydrogen assisted dissociation is demonstrated on the ZrO₂, CeZrO₂, and LaZrO₂ supports. In the absence of hydrogen, the presence of oxygen vacancies is shown to be necessary for CO₂ dissociation.     

TRIM25 and DEAD-Box RNA Helicase DDX3X Cooperate to Regulate RIG-I-Mediated Antiviral Immunity

The cytoplasmic retinoic acid-inducible gene-I (RIG-I)-like receptors (RLRs) initiate interferon (IFN) production and antiviral gene expression in response to RNA virus infection. Consequently, RLR signalling is tightly regulated by both host and viral factors. Tripartite motif protein 25 (TRIM25) is an E3 ligase that ubiquitinates multiple substrates within the RLR signalling cascade, playing both ubiquitination-dependent and -independent roles in RIG-I-mediated IFN induction. However, additional regulatory roles are emerging. Here, we show a novel interaction between TRIM25 and another protein in the RLR pathway that is essential for type I IFN induction, DEAD-box helicase 3X (DDX3X). In vitro assays and knockdown studies reveal that TRIM25 ubiquitinates DDX3X at lysine 55 (K55) and that TRIM25 and DDX3X cooperatively enhance IFNB1 induction following RIG-I activation, but the latter is independent of TRIM25’s catalytic activity. Furthermore, we found that the influenza A virus non-structural protein 1 (NS1) disrupts the TRIM25:DDX3X interaction, abrogating both TRIM25-mediated ubiquitination of DDX3X and cooperative activation of the IFNB1 promoter. Thus, our results reveal a new interplay between two RLR-host proteins that cooperatively enhance IFN-β production. We also uncover a new and further mechanism by which influenza A virus NS1 suppresses host antiviral defence.     

Preconditioning of AISI 304 stainless steel surfaces in the presence of flavins—Part I: Effect on surface chemistry and corrosion behavior

Stainless steel AISI 304 surfaces were studied after a mild anodic polarization for oxide growth in the presence and absence of two derivatives of vitamin B2 (riboflavin and flavin mononucleotide) that can be secreted by metal-reducing bacteria and act as a chelating agent for iron species. The alterations in oxide chemistry were studied by means of surface-sensitive techniques such as X-ray photoelectron spectroscopy and time-of-flight secondary ion mass spectrometry analysis. The complementary electrochemical characterization revealed a preferential growth of an oxide/hydroxide iron-rich film that is responsible for an altered pit initiation and nucleation behavior. These findings suggest that as the corrosion behavior is determined by the interplay of the chemical and electronic properties, only a mild anodic polarization in the presence of redox-active molecules is able to alter the chemical and electronic structure of the passive film formed on stainless steel AISI 304. This helps to achieve a profound understanding of the mechanisms of microbially influenced corrosion (MIC) and especially the possible effects of the redox-active biomolecules, as they may play an important role in the corrosion susceptibility of stainless steel surfaces.     

Continuous flame aerosol synthesis of carbon-coated nano-LiFePO4 for Li-ion batteries

Core–shell, nano-sized LiFePO₄-carbon particles were made in one step by scalable flame aerosol technology at 7 g/h. Core LiFePO₄ particles were made in an enclosed flame spray pyrolysis (FSP) unit and were coated in-situ downstream by auto thermal carbonization (pyrolysis) of swirl-fed C₂H₂ in an O₂-controlled atmosphere. The formation of acetylene carbon black (ACB) shell was investigated as a function of the process fuel-oxidant equivalence ratio (EQR). The core–shell morphology was obtained at slightly fuel-rich conditions (1.0<EQR<1.07) whereas segregated ACB and LiFePO₄ particles were formed at fuel-lean conditions (0.8<EQR<1). Post-annealing of core–shell particles in reducing environment (5 vol% H₂ in argon) at 700 °C for up to 4 h established phase pure, monocrystalline LiFePO₄ with a crystal size of 65 nm and 30 wt% ACB content. Uncoated LiFePO₄ or segregated LiFePO₄–ACB grew to 250 nm at these conditions. Annealing at 800 °C induced carbothermal reduction of LiFePO₄ to Fe₂P by ACB shell consumption that resulted in cavities between carbon shell and core LiFePO₄ and even slight LiFePO₄ crystal growth but better electrochemical performance. The present carbon-coated LiFePO₄ showed superior cycle stability and higher rate capability than the benchmark, commercially available LiFePO₄.     

Novel gelatin–alginate surgical sealants loaded with hemostatic agents

Surgical sealants are an integral part of the surgical toolbox. They are used mainly to seal tissues or suture lines. In the current research, we examined a novel surgical sealant based on the natural polymers gelatin and alginate, crosslinked with carbodiimide and loaded with hemostatic agents. Incorporation of the hemostatic agent montmorillonite significantly improved the ex vivo burst strength and the other physical properties (swelling ratio, weight loss, curing time, and viscosity) of the basic surgical sealant, due to the formation of nanocomposite structure. This novel system presents a new approach for improving the physical properties of surgical sealants.     

Scheduling directives: Accelerating shared-memory many-core processor execution

We consider many-core processors with a task-graph oriented programming model, whereby scheduling constraints among tasks are decided offline, and are then enforced by the runtime system using dedicated hardware. Here, exposing and beneficially exploiting fine grain data and control parallelism is increasingly important. Therefore, high expressive power for stating such constraints/directives, along with the ability to implement them in fast, simple hardware, is critical for success. In this paper, we focus on the relationship among different duplicable (multi-instance) tasks, which are used to express and exploit data parallelism. We extend the conventional Start-After-Complete (precedence) constraint to also be usable between replicas of different such tasks rather than only between entire tasks, thereby increasing the exposable parallelism. Additionally, we propose the parameterized Start-After-Start constraint, which can be used to control the degree of “lockstep” among multiple such tasks, e.g., in order to improve cache performance when the tasks work on the same data. Also, we briefly describe several additional interesting directives. Finally, we show that the directives can be supported efficiently in hardware. Hypercore, a very efficient CREW PRAM-like shared-cache architecture, which is very challenging because it has extremely fast dispatching for basic constraints, is used in the discussion. However, the new directives have broader applicability. Having shown the possibility of simple implementation and indications of benefit, this motivates further exploration of these directives and their implementation in hardware, as well as their support by programming tools.     

Time Domain Verification of Oscillator Circuit Properties

The application of formal methods to analog and mixed signal circuits requires efficient methods for constructing abstractions of circuit behaviors. This paper concerns the verification of properties of oscillator circuits. Generic monitor automata are proposed to facilitate the application of hybrid system reachability computations to characterize time domain features of oscillatory behavior, such as bounds on the signal amplitude and jitter. The approach is illustrated for a nonlinear tunnel-diode circuit model using PHAVer, a hybrid system analysis tool that provides sound verification results based on linear hybrid automata approximations and infinite precision computations.     

DNA interactions of a novel platinum drug, cis-[PtCl(NH3)2(N7-acyclovir)]+

We synthesized a novel platinum drug, cis-[PtCl(NH3)2(N7-ACV)]+, in which ACV is the antiviral drug acyclovir [a deoxyriboguanosine analogue, 9-(2-hydroxyethoxymethyl)guanine]. This new compound exhibits antiviral efficacy in vitro and exhibits an antitumor activity profile different from that of cisplatin [Metal-Based Drugs 2:249-256 (1995)]. To contribute to understanding the mechanisms underlying biological activity of this new compound, we studied modifications of natural and synthetic DNAs in cell-free media by cis-[PtCl(NH3)2(N7-ACV)]+ by various biochemical and biophysical methods. The results indicated that the major DNA adduct of cis-[PtCl(NH3)2(N7-ACV)]+ was a stable monofunctional adduct at guanine residues. In contrast to DNA adducts of other monodentate and clinically ineffective platinum(II) compounds, the adducts of cis-[PtCl(NH3)2(N7-ACV)]+ terminated in vitro DNA and RNA synthesis. In addition, although DNA adducts of cis-[PtCl(NH3)2(N7-ACV)]+ and cisplatin were different, some properties of DNA modified by either compound were qualitatively similar. Such similarities were not noticed if DNA modifications by other ineffective monofunctional platinum(II) complexes were investigated. Thus, the DNA binding mode of monofunctional cis-[PtCl(NH3)2(N7-ACV)]+ was different from that of other monofunctional but ineffective platinum(II) complexes. It has been suggested that the unique capability of cis-[PtCl(NH3)2(N7-ACV)]+ to modify DNA may be relevant to a distinct antitumor efficiency of this novel drug in comparison with cisplatin. It also has been suggested that at least some aspects of DNA interactions of cis-[PtCl(NH3)2(ACV)]+ revealed in the current study could be exploited in the search for and development of new antiviral platinum complexes containing, as a part of the coordination sphere, antiviral nucleosides.     

Is the response to cardiac pacing controlled by central venous temperature physiological?

Rate responsive cardiac pacemakers are capable of adapting their pacing rate according to metabolic demands in the physical effort and some of the sensors in use even according to such physiological stimuli in which the level of metabolism remains unchanged. Central blood temperature (CVT) could possibly represent a much-needed and searched ideal sensor, which truly reflects physiological processes. In order to verify the response of the thermistor sensor under various physiological conditions, 10 single-chamber VVIR pacemakers Thermos M 02 (Biotronik) were implanted since 1993 through 1995. Our group of patients consisted of 9 men and 1 women. 8 patients had chronic atrial fibrillation with bradycardia and ventricular chronotropic incompetence, 2 patients suffered from the 3rd degree atrioventricular block. The mean age at the time of implant was 62.4 (52-72) years, the mean follow-up period has amounted to 23 (2-32) months. The CVT response to physical exercise was proportional and smooth, especially in the strenuous physical effort. In contrast to some other sensors, CVT exhibited the physiological reaction also in situations in which the metabolic level did not change. It displayed a physiological circadian fluctuation of the pacing rate. Nevertheless, a markedly prolonged reaction time at the onset of physical exercise in the patients who were still "cold" was a shortcoming of this principle. The special sensor lead is a must and only the ventricular pacing is possible. Isolated CVT is not the ideal sensor but it be combined with fast sensors. It will undoubtedly be one of the sensors within the automatic multisensor pacemaker in the forseeable future. (Tab. 1, Fig. 1, Ref. 15.)     

First Hungarian experiences with positron emission tomography (PET) studies. Members of the PET working group

Diagnostic investigations commenced on the 28th of June 1994 in Hungary's and Central Europe's first PET Centre at the University Medical School of Debrecen. The Centre is equipped with a GE 4096 Plus whole body PET scanner. A metabolic tracer, 18F-deoxy-D-glucose (FDG), was used in the investigations. During the first 15 months 249 PET investigations were made in the Centre of which 242 were diagnostic and 7 normal subjects served as control for the patient studies with brain scans. The number of oncological indications (intra- and extracranial tumours, Hodgkin's lymphomas) was n = 105 (43.4% of the 242 diagnostic examinations), neurological investigations (without intracranial tumours) formed the dominant group (n = 117; 48.3%), whereas the number of cardiological indications was 20 (8.3%). The oncological studies included those of intracranial tumours (n = 76; 31.4%); thyroid tumours (n = 9; 3.7%); Hodgkin's lymphomas (n = 7; 2.9%) and other extracranial tumours (n = 13; 5.4%). The distribution of different neurological and psychiatric investigations was as follows: localization of focal epileptogen zone (n = 60; 24.8%); differential diagnosis of dementias (n = 30; 12.4%); exploration of cerebrovascular diseases (n = 10; 4.1%); and other neurological diseases (n = 17; 7.0%). The main objective of the cardiological PET investigations was the exploration of viable myocardium. The present paper overviews both the procedures (including administrative issues, as well) and the results of the first 249 FDG-PET investigations.