Festelektrolytzellen mit gasförmigen Vergleichselektroden zur Messung der Sauerstoffaktivität in Eisenschmelzen

Kritische Überprüfung des Anwendungsbereichs von stabilisiertem Zirkonoxid, Mullit und Magnesiumoxid in einer Festelektrolytzelle mit Luft als Sauerstoffvergleichspotential. Nachweis der Sauerstoffdurchlässigkeit fester Elektrolyte und der Ausbildung von Sauerstoffdiffusionsschichten an der Phasengrenze Festelektrolyt/Eisenschmelze. Voraussetzungen für eine korrekturfreie elektrochemische Sauerstoffbestimmung in Eisenschmelzen bei Verwendung von gasförmigen Sauerstoffvergleichspotentialen.     

Excessive Adventitial and Perivascular Vascularisation Correlates with Vascular Inflammation and Intimal Hyperplasia

Albeit multiple studies demonstrated that vasa vasorum (VV) have a crucial importance in vascular pathology, the informative markers and metrics of vascular inflammation defining the development of intimal hyperplasia (IH) have been vaguely studied. Here, we employed two rat models (balloon injury of the abdominal aorta and the same intervention optionally complemented with intravenous injections of calciprotein particles) and a clinical scenario (arterial and venous conduits for coronary artery bypass graft (CABG) surgery) to investigate the pathophysiological interconnections among VV, myeloperoxidase-positive (MPO⁺) clusters, and IH. We found that the amounts of VV and MPO⁺ clusters were strongly correlated; further, MPO⁺ clusters density was significantly associated with balloon-induced IH and increased at calciprotein particle-provoked endothelial dysfunction. Likewise, number and density of VV correlated with IH in bypass grafts for CABG surgery at the pre-intervention stage and were higher in venous conduits which more frequently suffered from IH as compared with arterial grafts. Collectively, our results underline the pathophysiological importance of excessive VV upon the vascular injury or at the exposure to cardiovascular risk factors, highlight MPO⁺ clusters as an informative marker of adventitial and perivascular inflammation, and propose another mechanistic explanation of a higher long-term patency of arterial grafts upon the CABG surgery.     

Using a Polygenic Score to Predict the Risk of Developing Primary Osteoporosis

Osteoporosis (OP) is a multifactorial bone disease belonging to the metabolic osteopathies group. Using the polygenic score (PGS) approach, we combined the effects of bone mineral density (BMD) DNA loci, affecting osteoporosis pathogenesis, based on GEFOS/GENOMOS consortium GWAS meta-analysis. We developed models to predict the risk of low fractures in women from the Volga-Ural region of Russia with efficacy of 74% (AUC = 0.740; OR (95% CI) = 2.9 (2.353–3.536)), as well as the formation of low BMD with efficacy of 79% (AUC = 0.790; OR (95% CI) = 3.94 (2.993–5.337)). In addition, we propose a model that predicts fracture risk and low BMD in a comorbid condition with 85% accuracy (AUC = 0.850; OR (95% CI) = 6.6 (4.411–10.608)) in postmenopausal women.     

Recognition of a Clickable Abasic Site Analog by DNA Polymerases and DNA Repair Enzymes

Azide–alkyne cycloaddition (“click chemistry”) has found wide use in the analysis of molecular interactions in living cells. 5-ethynyl-2-(hydroxymethyl)tetrahydrofuran-3-ol (EAP) is a recently developed apurinic/apyrimidinic (AP) site analog functionalized with an ethynyl moiety, which can be introduced into cells in DNA constructs to perform labeling or cross-linking in situ. However, as a non-natural nucleoside, EAP could be subject to removal by DNA repair and misreading by DNA polymerases. Here, we investigate the interaction of this clickable AP site analog with DNA polymerases and base excision repair enzymes. Similarly to the natural AP site, EAP was non-instructive and followed the “A-rule”, directing residual but easily detectable incorporation of dAMP by E. coli DNA polymerase I Klenow fragment, bacteriophage RB69 DNA polymerase and human DNA polymerase β. On the contrary, EAP was blocking for DNA polymerases κ and λ. EAP was an excellent substrate for the major human AP endonuclease APEX1 and E. coli AP exonucleases Xth and Nfo but was resistant to the AP lyase activity of DNA glycosylases. Overall, our data indicate that EAP, once within a cell, would represent a replication block and would be removed through an AP endonuclease-initiated long-patch base excision repair pathway.     

Size and Methylation Index of Cell-Free and Cell-Surface-Bound DNA in Blood of Breast Cancer Patients in the Contest of Liquid Biopsy

Aberrantly methylated circulating DNA (cirDNA) has proven to be a good cancer marker, but its detection is limited by low concentrations, fragmentation, and insufficiency. Since the methylated cirDNA was shown to be more stable in circulation than the unmethylated one and was shown to bind with the blood cell surface, we studied the concentration, representation, and fragmentation of tumor-derived methylated DNA in cell-free and cell-surface-associated DNA. We found that long DNA fragments (more than 10 kb) are mainly associated with the surface of blood cells. However, in plasma short DNA fragments (100–1000 bp) were also found along with long DNA fragments. Isolation of short fragments after separation of cirDNA in 6% PAGE followed by quantitative PCR (L1 element) has shown that short DNA fragments in healthy females represent 22% versus 0.5–4.4% in breast cancer patients. The methylated form of the RARβ2 gene was detected only in long DNA fragments by Real-time TaqMan PCR of bisulfite-converted DNA. The methylation index of cirDNA from healthy women was estimated at 0%, 9%, and 7% in plasma, PBS-EDTA, and trypsin eluates from the surface of blood cells, respectively. The methylation index of breast cancer patients’ DNA was found to be 33%, 15%, and 61% in the same fractions confirming the overrepresentation of methylated DNA in csbDNA.     

Insertion of Calcium-Permeable AMPA Receptors during Epileptiform Activity In Vitro Modulates Excitability of Principal Neurons in the Rat Entorhinal Cortex

Epileptic activity leads to rapid insertion of calcium-permeable α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors (CP-AMPARs) into the synapses of cortical and hippocampal glutamatergic neurons, which generally do not express them. The physiological significance of this process is not yet fully understood; however, it is usually assumed to be a pathological process that augments epileptic activity. Using whole-cell patch-clamp recordings in rat entorhinal cortex slices, we demonstrate that the timing of epileptiform discharges, induced by 4-aminopyridine and gabazine, is determined by the shunting effect of Ca²⁺-dependent slow conductance, mediated predominantly by K⁺-channels. The blockade of CP-AMPARs by IEM-1460 eliminates this extra conductance and consequently increases the rate of discharge generation. The blockade of NMDARs reduced the additional conductance to a lesser extent than the blockade of CP-AMPARs, indicating that CP-AMPARs are a more significant source of intracellular Ca²⁺. The study’s main findings were implemented in a mathematical model, which reproduces the shunting effect of activity-dependent conductance on the generation of discharges. The obtained results suggest that the expression of CP-AMPARs in principal neurons reduces the discharge generation rate and may be considered as a protective mechanism.     

Exact,almost and delayed fault detection: an observer based approach

This paper considers the problem of fault detection and isolation in continuous- and discrete-time systems while using zero or almost zero threshold. A number of different fault detection and isolation problems using exact or almost exact disturbance decoupling are formulated. Solvability conditions are given for the formulated design problems together with methods for appropriate design of observer based fault detectors. The 𝓁-step delayed fault detection problem is also considered for discrete-time systems. Moreover, certain indirect fault detection methods such as unknown input observers, eigenstructure assignment, factorization, and parity equation approaches are generalized by including the almost estimation methods in addition to exact estimation methods. Copyright © 1999 John Wiley & Sons, Ltd.     

Performance of large‐scale biomass gasifiers in a biorefinery,a state‐of‐the‐art reference

The Gothenburg Biomass Gasification plant (2015) is currently the largest plant in the world producing biomethane (20 MW_biomethane) from woody biomass. We present the experimental data from the first measurement campaign and evaluate the mass and energy balances of the gasification sections at the plant. Measures improving the efficiency including the use of additives (potassium and sulfur), high‐temperature pre‐heating of the inlet streams, improved insulation of the reactors, drying of the biomass and introduction of electricity as a heat source (power‐to‐gas) are investigated with simulations. The cold gas efficiency was calculated in 71.7%LHV_daf using dried biomass (8% moist). The gasifier reaches high fuel conversion, with char gasification of 54%, and the fraction of the volatiles is converted to methane of 34%_mass. Because of the design, the heat losses are significant (5.2%LHV_daf), which affect the efficiency. The combination of potential improvements can increase the cold gas efficiency to 83.5%LHV_daf, which is technically feasible in a commercial plant. The experience gained from the Gothenburg Biomass Gasification plant reveals the strong potential biomass gasification at large scale. © 2017 The Authors. International Journal of Energy Research published by John Wiley & Sons Ltd.     

An Efficient and Simple Procedure for the Preparation of α‐Keto‐β‐lactams

The methods for the preparation of α‐keto‐β‐lactams described in the literature are generally specific for a particular target molecule and lack generality. A short route to several of these compounds has been developed and is described in this communication. The protocol based on an efficient cyclization procedure followed by hydrolysis and oxidation allows preparation of α‐keto‐β‐lactams 5a—g with sensitive substituents.     

Pendant functional group copolyether sulfones. II. Modified copolyether sulfones with aminoazobenzene units

Modified copolyether sulfones with bulky azo pendant groups were synthesized by a polycondensation reaction of some polysulfones containing aldehyde groups with p‐aminoazobenzene. The corresponding model compound and an azo oligomer were also prepared to compare their properties. The structure of the resulting compounds was confirmed by IR, ¹H‐NMR spectra, and elemental analyses. The polymers were characterized by reduced viscosity, thermogravimetric analysis, and differential scanning calorimetry. The photochemical behavior of the azoaromatic chromophores was followed by UV‐visible absorption spectroscopy. Two kinds of photoreactions (photoisomerization and photodecoloration) operate in these polymers. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 2009–2016, 2000