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Zusammenfassung Ziel Etablierung von Referenzintervallen für Mangan (Mn) im Serum, Plasma und Vollblut bei adulten, gesunden Warmblutpferden mit bekannter Mn-Aufnahme und Vergleich von 2 analytischen Methoden der Mn-Bestimmung im Blut. Material und Methoden Zwischen Mai 2018 und November 2019 erfolgte auf 3 Gestüten bei 270 gesunden Pferden im Alter von 3–25 Jahren eine einmalige Blutprobenentnahme. In Vollblut, Plasma (Antikoagulans jeweils Lithium-Heparin [LH]) und Serum wurden die Mn-Konzentrationen mittels Massenspektrometrie mit induktiv gekoppeltem Plasma (ICP-MS) sowie mittels Atomabsorptionsspektrometrie (AAS) bestimmt. Die Referenzintervalle für jedes Substrat wurden nach den Empfehlungen der International Federation of Clinical Chemistry and Laboratory Medicine (IFCC) und des Clinical and Laboratory Standards Institute (CLSI) berechnet (Bereich zwischen 2,5- und 97,5-Perzentil der analysierten Mn-Blutkonzentration). Zeitgleich mit der Blutprobenentnahme wurden repräsentative Futterproben entnommen, um den Mn-Gehalt der korrespondierenden Fütterung zu bestimmen. Ergebnisse Die Pferde zeigten im Vollblut mit einer medianen Mn-Konzentration von 12,4 µg/l (Referenzintervall: 4,99–25,1 µg/l [AAS]; 5,99–25,3 µg/l [ICP-MS]) signifikant höhere Mn-Konzentrationen (p < 0,0001) als im korrespondierenden Serum (Median: 1,65 µg/l, Referenzintervall: 0,60–3,50 µg/l [AAS]; 1,11–2,96 µg/l [ICP-MS]) oder LH-Plasma (Median: 1,35 µg/l, Referenzintervall: 0,22–2,68 µg/l [AAS]; 0,59–2,45 µg/l [ICP-MS]). Im Methodenvergleich ergaben sich für LH-Plasma und Serum zwischen der AAS und der ICP-MS statistisch signifikante Abweichungen in den Mn-Bestimmungen, wohingegen sie für das Vollblut vergleichbare Ergebnisse lieferten. Schlussfolgerung und klinische Relevanz Vollblut weist durchschnittlich 10-fach höhere Mn-Konzentrationen auf als Serum oder LH-Plasma. Bei der Bewertung von Mn-Konzentrationen im Blut muss daher berücksichtigt werden, welches Probenmaterial analysiert wurde und welche Methode zur Anwendung kam, da in Serum und Plasma zwischen AAS und ICP-MS relevante Unterschiede auftreten können.

Testudinid herpesviruses (TeHVs) and ranaviruses are important pathogens of tortoises, but no treatments are available. Lysine may inhibit herpesvirus (HV) replication, although its effectivity has been questioned. Lactoferrin has antiviral activity against a range of viruses by inhibiting adsorption to cells. Media were supplemented with 6.25–10 mg/ml lysine and 0.625–1 mg/ml lactoferrin, individually or combined, and the effects measured against the replication of TeHV-1, TeHV-3, or a ranavirus in Terrapene heart cells (TH-1). Cytotoxicity testing was also carried out with the same concentrations. Lysine alone inhibited cell growth after 24 and 48 h, whereas lactoferrin only reduced cell growth after 24 h. TeHV-1 titers were only reduced by the addition of a combination of 10 mg/ml lysine and 1 mg/ml lactoferrin after 48 h (43.8% reduction) and by 10 mg/ml lysine (82.2% reduction). The same concentration of the combined substances led to an average reduction in TeHV-3 titers of 43.8% after 24 h and 68.4% after 48 h, respectively, while 10 mg/ml lysine led to an average reduction of 92.5% after 48 h. Lactoferrin alone did not reduce HV titers. Both concentrations of the combined substances led to titer reductions of the ranavirus (86.7–96.8%), and testing of the individual substances led to a reduction of 97.6% after 48 h with 10 mg/ml lysine and of 82.2% after 24 h with 1 mg/ml lactoferrin.

Introduction Phenobarbital is a commonly used anticonvulsant for the treatment of canine epileptic seizures. In addition to its central nervous system (CNS) depressing effects, long-term phenobarbital administration affects liver function. However, broader metabolic consequences of phenobarbital treatment are poorly characterized. Objectives To identify metabolic changes in the sera of phenobarbital-treated dogs and to investigate the relationship between serum phenobarbital concentration and metabolite levels. Methods Leftovers of clinical samples were used: 58 cases with phenobarbital concentrations ranging from 7.8 µg/mL to 50.8 µg/mL, and 25 controls. The study design was cross-sectional. The samples were analyzed by a canine-specific 1H NMR metabolomics platform. Differences between the case and control groups were evaluated by logistic regression. The linear relationship between metabolite and phenobarbital concentrations was evaluated using linear regression. Results Increasing concentrations of glycoprotein acetyls, LDL particle size, palmitic acid, and saturated fatty acids, and decreasing concentrations of albumin, glutamine, histidine, LDL particle concentration, multiple HDL measures, and polyunsaturated fatty acids increased the odds of the sample belonging to the phenobarbital-treated group, having a p-value .7. Albumin and glycoprotein acetyls had the best discriminative ability between the groups (AUC: .94). No linear associations between phenobarbital and metabolite concentrations were observed. Conclusion The identified metabolites are known to associate with, for example, liver and CNS function, inflammatory processes and drug binding. The lack of a linear association to phenobarbital concentration suggests that other factors than the blood phenobarbital concentration contribute to the magnitude of metabolic changes.

Summary Objective: The goal of this study was to establish reference intervals for blood parameters in rabbits based on data from routine diagnostic samples. Materials and methods: Data sets from 1679–2039 values for clinical chemistry and 937–1559 values for hematological parameters were evaluated using the statistical program Reference Limit Estimator 20151017. Results: The following reference intervals were calculated for hematology: erythrocytes 4.37–7.43 × 1012 cells/l; hematocrit 0.28–0.48 l/l; hemoglobin 89.63–153.82 g/l; leucocytes 2.71–12.23 × 109 cells/l; neutrophils 0.87–7.82 × 109 cells/l; lymphocytes 0.36–6.58 × 109 cells/l; monocytes 0.08–1.71 × 109 cells/l; eosi nophils 0.07–0.19 × 109 cells/l; basophils 0.06–1.1 × 109 cells/l; thrombocytes 225.45–905.3 × 109 cells/l. Calculated intervals for clinical chemistries were: alkaline phosphatase 9.05–94.68 U/l; aspartataminotransferase 3.75–32.44 U/l; creatine kinase 1.63–559.53 U/l; γ-glutamyltransferase 2.5–14.46 U/l; glutamatdehydrogenase 0.68–14.78 U/l; fructosamin 248.08–501.43 µmol/l; bile acid 0.76–19.63 μmol/l; total protein 48.66–73.64 g/l; urea 2.63–10.28 mmol/l; creatinine 51.38–154.35 µmol/l; calcium 3.02–4.3 mmol/l; magnesium 0.66–1.51 mmol/l; phosphorus 0.54–2.18 mmol/l; sodium 132.61– 154.0 mmol/l and potassium 3.52–6.04 mmol/l. Conclusion and clinical relevance: The calculation of intervals based on a large number of routine diagnostic samples allows the establishment of labora tory specific reference intervals without the use of experimental animals.

The evaluation of laboratory blood analytes is an important tool for health assessment in avian medicine. Unfortunately, there is a lack of suitable reference values for many zoo bird species. The goal of the present study was to establish reference intervals for a wide range of blood analytes in healthy black-headed ibis (Threskiornis melanocephalus) kept in a zoologic garden. Lithium heparinized blood samples from 15 individuals were collected, and 18 different clinical chemistry analytes were measured. New are especially the minimum and maximum values for bile acid (2.38-49.4 µmol/L), cholinesterase (439-1260 U/L), vitamin A (0.65-1.70 mg/L), vitamin E (26.3-52.5 mg/L), and capillary zone electrophoresis (prealbumin, 10.2-23.4%; albumin, 35.9-44.1%; A/G ratio, 1.07-1.69; α-, 15.7-20.0%; β-, 13.5-19.1%; γ-globulin, 6.08-11.3%). The measured values for clinical chemistry, vitamin, electrophoresis, and hematologic analytes are a basis for further studies and for diagnostics and clinical treatment in this ibis species.

The role of the perovskite lattice oxygen in the oxygen evolution reaction (OER) is systematically studied in the PrBaCo2O5+δ family. The reduced number of physical/chemical variables combined with in-depth characterizations such as neutron dif-fraction, O K-edge X-ray absorption spectroscopy (XAS), electron energy loss spectroscopy (EELS), magnetization and scanning transmission electron microscopy (STEM) studies, helps investigating the complex correlation between OER activity and a single perovskite property, such as the oxygen content. Larger amount of oxygen vacancies appears to facilitate the OER, possibly contributing to the mechanism involving the oxidation of lattice oxygen, i.e., the lattice oxygen evolution reaction (LOER). Furthermore, not only the number of vacancies but also their local arrangement in the perovskite lattice influences the OER activity, with a clear drop for the more stable, ordered stoichiometry., The X-ray absorption measurements were performed on the EPFL/PSI X-Treme beamline (O K-edge) and at the SuperXAS beamline (Co K-edge) at the Swiss Light Source, Paul Scherrer Institute, Villigen, Switzerland. The diffraction measurements were performed at the HRPT instrument at the Swiss spallation neutron source SINQ and at the MS-beamline at the Swiss Light Source at the Paul Scherrer Institute. The authors acknowledge the MS team for the measurements (Mesquik proposal 20182326). J.G. acknowledges Ramón y Cajal contract RYC-2012-11709 and the Severo Ochoa SEV-2015-0496 Project. The authors acknowledge the ICTS-CNME at UCM for offering access to their instruments and expertise and the Paul Scherrer Institute, for financial support through the internal CROSS project. T.J.S. thanks Innosuisse and the Swiss Competence Centre for Energy Research (SCCER) Heat & Electricity Storage.

IntroductionBacterial pathogens are often involved in dermatitis in reptiles. Exact identification of reptile-specific but otherwise uncommon bacterial species may be challenging. However, identification is crucial to evaluate the importance of the detected bacterial species.ObjectiveThe aim of this study was to assess the number of aerobic bacterial isolates cultured from skin-derived samples of reptiles which were not reliably identified by Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry (MALDI-TOF MS), and to determine their identity.Material and methodsRoutine bacterial diagnostics were performed on 235 skin samples, and 417 bacterial isolates were analysed by MALDI-TOF MS. The isolates were grouped into categories based on their first score: category I (≥ 2.00), category II (≥ 1.70 and < 2.00), and category III (< 1.70). Isolates from category III were further investigated by 16S rRNA gene sequencing and the following criteria were applied: query cover 100%, e-value rounded to 0.0 and sequence identity (%) > 98.00% for genus identification, and > 99.00% for species identification.ResultsThe majority of bacterial isolates were in category I (85.1%) or category II (8.4%). In category III (6.5%) results achieved at first by MALDI-TOF MS corresponded to the results of the molecular analysis in 8.0% of isolates at the species level and in 24.0% at the genus level. Bacterial isolates classified as category III were heterogenic in genus (e.g. Chryseobacterium, Devriesea, Pseudomonas, Staphylococcus, Uruburuella), and some have only been described in reptiles so far.ConclusionsMost of the aerobic bacterial isolates cultured from reptile skin achieved high scores by MALDI-TOF MS. However, in the majority of category III isolates MALDI-TOF MS results were different from those of the molecular analysis. This strengthens the need to carefully examine low-scored results for plausibility and to be familiar with the occurrence and morphology of relevant reptile-specific bacterial species (e.g. Devriesea agamarum) as well as with the limits of the database used.

The ability to localize selected chemical elements within individual components of functional matter is of great value to our understanding of material behavior. By means of resonant ptychographic X-ray computed tomography, we here provide such colocalization information with nanoscopic spatial resolution. Spatially correlated quantitative tomograms of electron density and iron concentration allowed the localization of native and feedstock-introduced iron impurities within the primary components of a prominent heterogeneous catalyst. Examinations found no direct evidence in favor of the currently suggested impurity-driven deactivation mechanisms of fluid catalytic cracking catalysts. The majority of iron impurities, present in the form of nanosized magnetite particulates, are found embedded in the outermost layer of an otherwise iron-poor, particle isolating amorphous silica–alumina envelope. Observations query both deactivation driven by impurity pore clogging and iron-impurity induced melting of catalys...

Portland-cement based concrete samples were incubated for 28 days (short-term) in microbially derived H2SO4 (pH 1.3–2.4) and chemically generated H2SO4 (pH 1.0 and 2.0) to investigate potential differences between the two acid attacks. Additionally, long-term biogenic experiments were performed over two, three and six months to evaluate the corrosion behavior over time. Corrosion was evaluated by visual, physical and chemical parameters, including laser ablation inductively coupled plasma mass spectrometry. The 28-day experiments revealed a pH-dependent degree of damage. No obvious differences between biologically and chemically generated H2SO4 were observed based on similar elemental distributions in the corrosion layers. For the long-term experiments, the corrosion primarily depended on the amount of H2SO4 produced by A. thiooxidans which varied within different set-ups. No linear relation between the degradation and incubation periods was observed. In all set-ups, gypsum was the main corrosion product and no microbial growth was observed within the corrosion layer.

ZusammenfassungGegenstand: In einem Line-Immunoassay mit sieben Antigenen sowie rekombinantem VlsE (variable major protein like sequence, expressed) und synthetischem C6-Peptid wurde die Präsenz Borreliaburgdorferi-spezifischer Antikörper (IgG) in kaninen Seren erfasst. Ziel der Studie war, die Antikörperantworten gegen das C6-Peptid und das VlsE-Protein zu vergleichen und zu evaluieren, ob diese divergieren, da Antikörper gegen die jeweiligen Antigene als spezifisch für eine stattgefundene Infektion mit Borrelien gelten. Material und Methoden: Es wurden 1355 Blutproben von Hunden analysiert, bei denen Verdacht auf eine Infektion mit Borrelien bestand. Die Testung erfolgte mittels eines Line-Immunoassays (IgG) mit neun Antigenen. Ergebnisse: Insgesamt 64,4% der Proben wurden als negativ bewertet, 16,4% als infiziert und 17,4% zeigten ein für eine Impfung spezifisches Bandenmuster. Bei 1,2% der Hunde lag sowohl eine Impfung als auch eine Infektion vor. Die am häufigsten positiv getesteten Banden waren p100 (24,3%), p31/OspA (18,5%), C6 (16,3%) und VlsE (13,9%). Bei 236 Hunden wurden Antikörper gegen das VlsE-Protein und/oder das C6-Peptid nachgewiesen. Während 73,3% dieser Hunde übereinstimmende Ergebnisse zwischen VlsE und C6 aufwiesen, unterschieden sich bei 26,7% die Resultate. Schlussfolgerung und klinische Relevanz: Die Testung mittels Line-Immunoassay erlaubt eine qualitative Analyse der unterschiedlichen IgG-Immunantworten gegen verschiedene Antigene. Die Resultate der Immunantworten gegen die als infektionsspezifisch geltenden Antigene VlsE und C6 divergierten bei mehr als 26% der positiv getesteten Hunde unserer Population, sodass zum Ausschluss oder der Bestätigung einer Infektion mit Borrelia burgdorferi möglichst unterschiedliche infektionsspezifische Banden berücksichtigt werden sollten.

Noble metals are added to boiling water reactors (BWRs) to mitigate stress corrosion cracking of structural components made from steels and Ni-based alloys and this technology is referred to as Noble Metal Chemical Addition (NMCA) or NobleChemTM. There is a growing concern that NMCA can cause unwanted harmful effects on the corrosion and hydrogen uptake properties of Zircaloy-2 fuel cladding. To investigate this, we have subjected Zircaloy-2 fuel claddings to out-of-pile BWR conditions in a custom-built autoclave. These claddings are oxidized in pressurized hot water (280 °C, 9 MPa) for 25, 60 and 150 days, wherein Pt nanoparticles (~10 nm) were simultaneously injected. Cross-sectional focused ion beam cuts made at the oxide-metal interface reveal that the oxide growth is not significantly influenced by the local Pt loadings (≤ 1 µg·cm-2). Surprisingly, an inverse correlation was observed between oxide thicknesses and metal's hydrogen contents. Interestingly, Pt catalysts have led to diminished hydrogen absorption in specimens with liner exposed to the hot water. Overall, Pt catalysts exhibited no detrimental effects on the corrosion rate and hydrogen absorption in Zircaloy-2.

The aim of this study was to investigate the relative role of chemically and microbially derived sulfuric acid (H 2 SO 4 ) corrosion on hardened cement paste representing a concrete binder. Cement stone disks were exposed to chemical H 2 SO 4 (pH 1.0 and 2.0) and biological H 2 SO 4 (pH 1.5–2.1). After 28 days, the degree of damage was evaluated by common visual-physical parameters and laser ablation-ICP-MS as a novel evaluation tool to assess changes in elemental distributions. The results revealed a pH-dependent degree of damage. The 4 mm thick disk at pH 1.0 was completely corroded. For the disks exposed to biogenic and chemical H 2 SO 4 at pH 2.0 an intact core remained with a similar thickness of the corrosion layer (1.8–2.0 mm) and sulfuric acid penetration depth (1.1–1.3 mm). Since the elemental distribution was similar in the corroded layer independent of applying biological or chemical H 2 SO 4 , no obvious differences between the two acid attacks were revealed.

A cationic monomeric surfactant (CMS) and a cationic gemini surfactant (CGS) were successfully synthesized and characterized. A comparison of the CMS and CGS metal corrosion inhibitory effects was carried out on the basis of protecting a metal surface from cultivated salinity (3.18% NaCl) and an environmental sulfidogenic bacterial activity in a reactor's bulk phase (planktonic) and on a metal surface (sessile). Environmental sulfidogenic bacterial consortia were originated from an oil-field water tank. The sulfidogenic bacterial activities were evaluated based on redox potential and sulfide concentrations in the reactor's bulk phase. In addition, changes in biofilm structures and constituents and the metal corrosion rate were determined to estimate changes on metal surfaces. Results in the reactor's bulk phases showed that at high surfactant (CMS, CGS) concentrations, a considerable decline in the redox potential was observed and the sulfide productivity was completely suppressed. The synthesized surfactants showed the highest metal corrosion inhibition efficiencies of 92% and 94% at concentrations of 10 mM and 1 mM for the CMS and the CGS, respectively. In addition, the synthesized CMS and CGS showed nonspecific antibacterial activity against Gram-positive and Gram-negative bacterial-standard strains.

Triggering or enhancing antitumor activity of tumor-associated macrophages is an attractive strategy for cancer treatment. We have previously shown that the cytokine interferon-γ (IFN-γ), a type II IFN, could synergize with toll-like receptor (TLR) agonists for induction of antitumor M1 macrophages. However, the toxicity of IFN-γ limits its clinical use. Here, we investigated whether the less toxic type I IFNs, IFN-α, and IFN-β, could potentially replace IFN-γ for induction of antitumor M1 macrophages. We measured in vitro the ability of type I and II IFNs to synergize with TLR agonists for transcription of inducible nitric oxide synthase (iNOS) mRNA and secretion of nitric oxide (NO) by mouse bone marrow-derived macrophages (BMDMs). An in vitro growth inhibition assay was used to measure both cytotoxic and cytostatic activity of activated macrophages against Lewis lung carcinoma (LLC) cancer cells. We found that both type I and II IFNs could synergize with TLR agonists in inducing macrophage-mediated inhibition of cancer cell growth, which was dependent on NO. The ability of high dose lipopolysaccharide (LPS) to induce tumoricidal activity in macrophages in the absence of IFN-γ was shown to depend on induction of autocrine type I IFNs. Antitumor M1 macrophages could also be generated in the absence of IFN-γ by a combination of two TLR ligands when using the TLR3 agonist poly(I:C) which induces autocrine type I IFNs. Finally, we show that encapsulation of poly(I:C) into nanoparticles improved its potency to induce M1 macrophages up to 100-fold. This study reveals the potential of type I IFNs for activation of antitumor macrophages and indicates new avenues for cancer immunotherapy based on type I IFN signaling, including combination of TLR agonists.

The experimental data on calcium phosphates formation were collected in dilute solution at constant pH (7.40) and temperature (37.0 °C) at different levels of ionic strength (IS). The evolution of the solid phase formation is described in detail using a thermodynamic-kinetic model. The thermodynamic model takes into account all relevant chemical species as well as Posner’s clusters; the kinetic model, based on the discretized population balance approach, accounts for the solid formation from solution. The experimental data are consistent with an initial formation of dicalcium phosphate dihydrate (DCPD, brushite), which dominates the nucleation rate, and its rapid transformation into octacalcium phosphate (OCP) or hydroxyapatite (HA), which dominates the growth rate. Depending on the experimental conditions and, including the influence of the IS level, OCP may be further transformed into apatite. The classical nucleation theory is able to describe the experimental results very well and the solid phase growth is limited by the diffusion of Ca2+ ions. The precipitation pathway described by a complete thermodynamic-kinetic model is expected to contribute to the understating of the in vivo osteogenesis. Statement of Significance The formation mechanism of calcium phosphates under biomimetic conditions is unraveled. The formation pathway is mathematically described based on a thermodynamic-kinetic model in which (i) the nucleation stages (primary and secondary) are dominated by the formation of dicalcium phosphate dihydrate (DCPD) and (ii) the fast growth stage is limited by the diffusion of Ca2+ ions under the driving force of octacalcium phosphate (OCP), or hydroxyapatite (HA), solubility. The obtained solid phase seems correlated to the activity coefficient of phosphate ions, thus to the ionic strength and local phosphate speciation. The model, being able to highlight the details of the precipitation pathway, is expected to contribute to the understanding of the apatitic phase formation in the biomineralization-biodemineralization processes under in-vivo conditions.

The release of secondary nano-objects formed during waste combustion processes is becoming a matter of concern, considering their known toxicity and the fact that the 100% efficiency of filtering systems is not always ensured. An increased cytotoxicity and genotoxicity on human peripheral blood lymphocytes is known particularly in the case of ZnO, which is often contained in paints and waterproof agents, heading to a relevant quantity present in the waste wood material. In this study, the behavior of ZnO nanoparticles during wood combustion and the effect of the reduction potential of generated carbon species on the release of secondarily formed ZnO-containing nano-objects were investigated. By hyphenating a modified scanning mobility particle sizer (SMPS) and inductively coupled mass spectrometry (ICP-MS), it was possible to obtain simultaneously size-resolved and chemical information on the emitted nanoparticles. Through the established correlation between SMPS and ICP-MS signals, Zn-containing particles were efficiently resolved from the combustion generated particles. Transmission electron microscopy (TEM) and energy-dispersive X-ray spectroscopy (EDS) on size-selected particles confirmed the SMPS and ICP-MS data. The use of electron diffraction allowed determining the structure of the crystalline materials as hexagonal ZnO. A possible mechanism of reduction of ZnO to Zn and further reformation as secondary nano-objects is proposed.

A cationic gemini surfactant was synthesized and characterized. The surfactant was successfully applied as a biocide against environmental sulfidogenic bacteria in the bulk phase (planktonic) and on the surface (biofilm). The activity of the synthesized surfactant was discussed based on the redox potential and the sulfide productivity in the bulk phase. The cultivated biofilm structure analysis and corrosion rate were estimated on the metal surface. The lowest metal corrosion rate was recognized at a concentration of 1 mM with a metal corrosion inhibition efficiency of 95%. The synthesized gemini surfactant prevented the biofilm formation at a concentration of 0.1 mM. The synthesized gemini surfactant displayed a broad spectrum antibacterial activity against Gram-positive and Gram-negative bacteria.

The application of a boron-doped diamond electrode in electrochemical water disinfection was investigated with respect to its inactivation potential of three indicator microorganisms. Drinking water and the effluent of a wastewater treatment plant spiked with Escherichia coli, Enterococcus faecium and Pseudomonas aeruginosa were electrolysed under different conditions in a batch reactor. All three bacteria species could be successfully inactivated in drinking water. The disinfection rate depended on the applied charge, with far more efficiency at high current densities (208 and 333 mA/cm2) under high ozone concentrations measured in contrast to low current densities (42 mA/cm2) where bacterial inactivation was rather driven by hydroxyl radicals. When oxidising a target pharmaceutical compound in the wastewater treatment plant effluent, the water matrix exhibited an ozone scavenging effect. The resulting decrease in the efficiency could not be detected for the disinfection experiments in the complex water matrix compared to drinking water, which indicates a different disinfection mechanism, probably due to reactive chlorine species.

Highly active and durable oxygen reduction catalysts are needed to reduce the costs and enhance the service life of polymer electrolyte fuel cells (PEFCs). This can be accomplished by alloying Pt with a transition metal (for example Ni) and by eliminating the corrodible, carbon-based catalyst support. However, materials combining both approaches have seldom been implemented in PEFC cathodes. In this work, an unsupported Pt-Ni alloy nanochain ensemble (aerogel) demonstrates high current PEFC performance commensurate with that of a carbon-supported benchmark (Pt/C) following optimization of the aerogel's catalyst layer (CL) structure. The latter is accomplished using a soluble filler to shift the CL's pore size distribution towards larger pores which improves reactant and product transport. Chiefly, the optimized PEFC aerogel cathodes display a circa 2.5-fold larger surface-specific ORR activity than Pt/C and maintain 90 % of the initial activity after an accelerated stress test (vs. 40 % for Pt/C).

The corrosion inhibitor 5-tolyltriazole (5-TTri) can have a detrimental impact on aquatic systems thus implying an acute need to reduce the effluent concentrations of 5-TTri. In this study, 5-TTri biodegradation was enhanced through acclimation and nutrient supply. Activated sludge communities (ASC) were setup in nine subsequent ASC generations. While generation two showed a lag phase of five days without biodegradation, generations four to nine utilized 5-TTri right after inoculation, with biodegradation rates from 3.3 to 5.2 mg L(-1)d(-1). Additionally, centrifuged AS supernatant was used to simulate the nutrient conditions in wastewater. This sludge supernatant (SS) significantly enhanced biodegradation, resulting in removal rates ranging from 3.2 to 5.0 mg L(-1)d(-1) without acclimation while the control groups without SS observed lower rates of ⩽ 2.2 mg L(-1)d(-1).

We present a method for monolithically integrating mismatched semiconductor materials with Si, coined three-dimensional (3D) heteroepitaxy. The method comprises the replacement of conventional, continuous epilayers by dense arrays of strain- and defect-free, micron-sized crystals. The crystals are formed by a combination of deep-patterning of the Si substrates and self-limited lateral expansion during the epitaxial growth. Consequently, the longstanding issues of crack formation and wafer bowing can be avoided. Moreover, threading dislocations can be eliminated by appropriately choosing pattern sizes, layer thicknesses and surface morphology, the latter being dependent on the growth temperature. We show this approach to be valid for various material combinations, pattern geometries and substrate orientations. We demonstrate that Ge crystals evolve into perfect structures away from the heavily dislocated interface with Si, by using a synchrotron X-ray beam focused to a spot a few hundred nanometers in size and by recording 3D reciprocal space maps along their height. Room temperature photoluminescence (PL) experiments reveal that the interband integrated PL intensity of the Ge crystals is enhanced by almost three orders of magnitude with respect to that of Ge epilayers directly grown on flat Si substrates. Electrical measurements performed on single heterojunction diodes formed between 3D Ge crystals and the Si substrate exhibit rectifying behavior with dark currents of the order of 1 mA/cm2. For GaAs the thermal strain relaxation as a function of pattern size is similar to that found for group IV materials. Significant differences exist, however, in the evolution of crystal morphology with pattern size, which more and more tends to a pyramidal shape defined by stable {111} facets with decreasing width of the Si pillars. © 2013 Elsevier B.V.

A novel cationic gemini surfactant (NCGS) was synthesized and characterized. The inhibitory effect of NCGS was evaluated on the basis of protecting a metal surface from the salinity (5.49 % NaCl) and the activity of environmental sulfidogenic bacteria which originated from an oil-field water tank. Sulfidogenic bacterial activities were determined based on sulfide production, redox potential, changes in biofilm structures and constituents and metal corrosion rate calculations. At high surfactant concentrations, the sulfide production was completely inhibited as well as a considerable drop in the redox potential was observed in the reactor’s bulk phase. A minimum inhibitory concentration of the NCGS was achieved at a concentration of 1 mM. The NCGS showed a high ability to inhibit a biofilm over the metal surface at a concentration of 0.1 mM. The lowest metal corrosion rate was detected at a concentration of 5 mM with a metal corrosion inhibition efficiency of 97 %. In addition the NCGS showed a nonspecific biocidal activity against Gram-positive and Gram-negative bacterial strains.

In this report we present a novel strategy in selective epitaxial growth on top of Si pillars, which results in a tessellated Ge film, composed by self-aligned micron-sized crystals in a maskless process. Modelling by rate equations the morphology evolution of fully facetted crystal profiles is extensively outlined, showing an excellent prediction of the peculiar role played by flux shielding among microcrystals, in the case of dense array configuration. Crack formation and substrate bending, caused by the mismatch in thermal expansion coefficients, are eliminated by the mechanical decoupling among individual microcrystals, which are also shown to be dislocation- and strain-free. The method has been also tested for Si 1− x Ge x alloys, with compositions ranging from pure silicon to pure germanium. There are ample reasons to believe that this approach could be extended to other material combinations and substrate orientations, actually providing a technology platform for several device applications.

Potential aerobic biodegradation mechanisms of the widely used polar, low-adsorptive sulfonamide antibiotic sulfamethoxazole (SMX) were investigated in activated sludge at bench scale. The study focused on (i) SMX co-metabolism with acetate and ammonium nitrate and (ii) SMX utilization when present as the sole carbon and nitrogen source. With SMX adsorption being negligible, elimination was primarily based on biodegradation. Activated sludge was able to utilize SMX both as a carbon and/or nitrogen source. SMX biodegradation was enhanced when a readily degradable energy supply (acetate) was provided which fostered metabolic activity. Moreover, it was raised under nitrogen deficiency conditions. The mass balance for dissolved organic carbon showed an incomplete SMX mineralization with two scenarios: (i) with SMX as a co-substrate, 3-amino-5-methyl-isoxazole represented the main stable metabolite and (ii) SMX as sole carbon and nitrogen source possibly yielded hydroxyl-N-(5-methyl-1,2-oxazole-3-yl)benzene-1-sulfonamide as a further metabolite.

Asymmetric separators with polysulfide barrier properties consisting of porous polypropylene grafted with styrenesulfonate (PP-g-PLiSS) were characterized in lithium-sulfur cells to assess their practical applicability. Galvanostatic cycling at different C-rates with and without an electrolyte additive and cyclic voltammetry were used to probe the electrochemical performance of the cells with the PP-g-PLiSS separators and to compare it with the performance of the cells utilizing state-of-the-art separator, Celgard 2400. Overall, it was found that regardless of the applied cycling rate, the use of the grafted separators greatly enhances the Coulombic efficiency of the cell. An appropriate Li-exchange-site (-SO3(-)) concentration at and near the surface of the separator was found to be essential to effectively suppress the polysulfide shuttle without sacrificing the Li-ion mobility through the separator and to improve the practical specific charge of the cell.

Single-stage nitritation–anammox combines the growth of aerobic ammonium-oxidizing bacteria (AOB) and anaerobic ammonium oxidizing bacteria (AnAOB) in one reactor. The necessary compromise of their milieu conditions often leads to the growth of nitrite-oxidizing bacteria (NOB). For this study, a sequencing batch reactor (SBR) for nitritation–anammox was operated for 180 days with sewage sludge reject water (removal capacity, 0.4 kg N m−3 day−1). The growth of NOB was favored by enhanced oxygen supply rather than extended aerobic phases. Suspended-type biomass from this SBR was taken regularly and sieved into three size fractions (all of them

While HRTEM is the well-established method to characterize the structure of dodecagonal tantalum (vanadium) telluride quasicrystals and their periodic approximants, phase-contrast imaging performed on an aberration-corrected scanning transmission electron microscope (STEM) represents a favorable alternative. The (Ta,V)151Te74 clusters, the basic structural unit in all these phases, can be visualized with high resolution. A dependence of the image contrast on defocus and specimen thickness has been observed. In thin areas, the projected crystal potential is basically imaged with either dark or bright contrast at two defocus values close to Scherzer defocus as confirmed by image simulations utilizing the principle of reciprocity. Models for square–triangle tilings describing the arrangement of the basic clusters can be derived from such images.

Ge-rich multiple quantum well heterostructures have been investigated as engineered material for efficient thermoelectric generators monolithically integrated on silicon substrates. Thick Ge/SiGe multilayers on Si substrates designed for lateral thermoelectric devices have been grown and characterized in which electrical and thermal conduction occur parallel to the heterostructure interfaces. In this study, an overview of the investigated structures is presented together with results from X-ray scattering and transmission electron microscopy experiments. These analyses confirm the high quality of the material and the uniformity of the structure over the whole deposited thickness. Important parameters in terms of the optimization of the material quality which could affect thermoelectric properties, such as the interfaces roughness and the threading dislocation density, have also been evaluated. Preliminary electrical and Seebeck coefficient measurements indicate the viability of this material for the realization of thermoelectric devices.

BACKGROUND: Emerging resistance to anticoagulant rodenticides may significantly impair house mouse (Mus musculus L.) control. As in humans and rats, sequence variants in the gene vitamin K epoxide reductase complex subunit 1 (VKORC1) of house mice are strongly implicated in the responses of mice to anticoagulants. This study gives a first overview of the distribution and frequency of such potentially resistance-conferring sequence variants in house mice, based on tissue samples from 30 populations in Germany, Switzerland and the Azores. RESULTS: Except for one population from south Germany, sequence variants were found in individuals from all locations sampled (29 out of 30 sites surveyed), with less than 10% of the individuals matching the wild-type genotype. The most frequent and widespread amino acid substitutions were Leu128Ser, Tyr139Cys and a group of linked sequence changes (Arg12Trp/Ala26Ser/Ala48Thr/Arg61Leu). Where these substitutions occurred as the sole variant, the proportion of homozygous individuals was 72-83%. CONCLUSIONS: An evaluation of published data revealed that the three most frequently found sequence variants are associated with a substantial loss of rodenticide efficacy of first-generation anticoagulants (e.g. warfarin, coumatetralyl), as well as the second-generation compound bromadiolone and most probably also difenacoum. Knowledge of the distribution and frequency of resistance-conferring sequence variants will stimulate their further functional characterisation and facilitate the choice of effective active substances for house mouse control.

We demonstrate mid-infrared emission from cascade structures based on InAs quantum dashes (QDashes) grown on tensile-strained AlInAs. The proposed design relies on a diagonal transition from the QDash ground state to the following quantum well. The measured electroluminescence is very broad and tunes strongly with the applied voltage. A comparison with an identical structure, where the dashes were replaced by a lattice-matched InGaAs quantum well (QW), shows quite different transport properties. A sharp alignment between the injector and the optical transition upper state is present in the QW sample, while the alignment is smoother in the QDash one. Moreover, the QW device exhibits a negative differential resistance not present in the QDash one. This can be attributed to the inhomogeneous nature of the QDashes. Decreasing the tunneling barrier between the QDashes and the following QW increases the injected current as does increasing the doping in the active region. A gain extrapolation from our electroluminescence measurements shows that these structures are promising for the development of quantum cascade lasers based on a 3D confined active region.

An error analysis for real surface area ( A m ) measurements of Pt 3 Co/C catalysts is presented. The real surface area was measured by X-ray diffraction (XRD), high resolution transmission electron microscopy (HRTEM), desorption of underpotential deposited hydrogen (H upd ) and CO-stripping voltammetry. All measurements were carried out after an electrochemical activation by cyclic voltammetry in perchloric acid. The real surface area decreases in the sequence A m (XRD) ∼ A m (HRTEM) > A m (CO-stripping) ∼ A m (H upd ). HRTEM provides the highest reliability of the investigated methods. The electrochemical methods are questionable for Pt 3 Co/C catalysts. They yield surface areas which are 23–30% lower than determined by HRTEM. The surface coverage of adsorbed H and CO is apparently lower on Pt 3 Co compared to Pt nanoparticles. Cyclic voltammetry of Pt 3 Co/C in alkaline electrolyte suggests that the surface of acid leached Pt 3 Co nanoparticles consists of pure Pt.

Silicon-rich SiGe alloys represent a promising platform for the development of large-area single-mode optical waveguides to be integrated in silicon-based optical circuits. We find that SiGe layers epitaxially grown on Si successfully guide radiation with a 1.55 μm wavelength, but, beyond a critical core thickness, their optical properties are strongly affected by the clustering of misfit dislocations at the interface between Si and SiGe, leading to a significant perturbation of the local refractive index. Transmission electron microscopy and micro-Raman spectroscopy, together with finite-element simulations, provide a complete analysis of the impact of dislocations on optical propagation. © 2009 Elsevier B.V. All rights reserved.

Electron microscopy studies are used to explore the morphology of thin poly(3,4-ethylenedioxythiophene) and polystyrene sulfonate acid (PEDOT:PSS) films. The figures show that the films are composed of grains with diameters in the range of about 50 nm. Energy dispersive X-ray spectroscopy analysis reveals that individual grains have a PEDOT-rich core and a PSS-rich shell with a thickness of about 5–10 nm. Atomic force microscopy (AFM) is then used to analyze the topography of fracture surfaces of ruptured PEDOT:PSS tensile specimens. These AFM scans also show that the films are composed of grains dispersed in a matrix. The investigations presented herein yield a picture of PEDOT:PSS morphology with unprecedented clarity.

PtCo3/C catalysts for oxygen reduction were prepared and heat-treated between 350 and 1000 °C under reductive conditions. The catalysts were activated by cyclic voltammetry, which resulted in the p...

A novel process of morphological evolution was observed on a polycrystalline platinum electrode surface during intensive potential perturbation in sulfuric acid electrolyte. The process was started from a smooth polycrystalline platinum surface, and ended up with a roughened overlayer which is composed of numerous morphological units. According to its appearance, the unit is named “feather-like morphology (FLM)” which contains finer structures at nanometer scale. The active surface area of platinum at different stages during the morphological evolution was estimated by cyclic voltammetry. Electron microscopic measurements provided both morphological details and crystallographic information.

Modern nanotechnology offers routes to create new artificial materials, widening the functionality of devices in physics, chemistry, and biology. Templated self-organization has been recognized as a possible route to achieve exact positioning of quantum dots to create quantum dot arrays, molecules, and crystals. Here we employ extreme ultraviolet interference lithography (EUV-IL) at a wavelength of lambda = 13.5 nm for fast, large-area exposure of templates with perfect periodicity. Si(001) substrates have been patterned with two-dimensional hole arrays using EUV-IL and reactive ion etching. On these substrates, three-dimensionally ordered SiGe quantum dot crystals with the so far smallest quantum dot sizes and periods both in lateral and vertical directions have been grown by molecular beam epitaxy. X-ray diffractometry from a sample volume corresponding to about 3.6 x 10(7) dots and atomic force microscopy (AFM) reveal an up to now unmatched structural perfection of the quantum dot crystal and a narrow quantum dot size distribution. Intense interband photoluminescence has been observed up to room temperature, indicating a low defect density in the three-dimensional (3D) SiGe quantum dot crystals. Using the Ge concentration and dot shapes determined by X-ray and AFM measurements as input parameters for 3D band structure calculations, an excellent quantitative agreement between measured and calculated PL energies is obtained. The calculations show that the band structure of the 3D ordered quantum dot crystal is significantly modified by the artificial periodicity. A calculation of the variation of the eigenenergies based on the statistical variation in the dot dimensions as determined experimentally (+/-10% in linear dimensions) shows that the calculated electronic coupling between neighboring dots is not destroyed due to the quantum dot size variations. Thus, not only from a structural point of view but also with respect to the band structure, the 3D ordered quantum dots can be regarded as artificial crystal.

In this work we address three dimensional heterojunctions demonstrating that photoluminescence from defect free Ge/SiGe multiple quantum well (MQW) micro crystals grown on deeply patterned Si(001) and Si(111) substrates exhibit similar radiative intensity and analogous spectral shape. The finite lateral size and faceted top morphology of the micro crystals guarantee the absence of dislo cations threading through the MQW structure and the dominance of radiative recombination at slanted {113} facets. Our approach yields superior optical quality in comparison to state of the art MQWs grown on SiGe/Si(001) linearly graded buffers.

We present a method to produce thin SiGe virtual substrates suitable for electronic applications. This method is based on the gas phase process of low-energy plasma-enhanced chemical vapor deposition. The strain-relaxed buffers are characterized by X-ray diffractometry, transmission electron microscopy and atomic force microscopy. We find threading dislocation densities lower than 3 � 10 8 cm � 2 and a surface rms roughness of 1.8 nm, for a buffer thickness of 500 nm. Room temperature electrical results are also presented, which are competitive with those obtained on SiGe buffers produced by other methods. r 2005 Elsevier B.V. All rights reserved.

We fabricate and demonstrate optically active quantum dots embedded in single nanowires. Observation of photon antibunching proves the zero dimensionality of these heterostructures that can be epitaxially grown on various substrates, including silicon. We show that the nanowire dots are intense single photon sources, typically an order of magnitude brighter than self-assembled quantum dots. Due to control over their composition, size, and position, nanowire dots are ideal building blocks for fully controlled quantum dot molecules.

We have investigated strain compensated Si/Si 0.2 Ge 0.8 multilayers, which were grown pseudomorphically on relaxed Si 0.5 Ge 0.5 pseudosubstrates by molecular beam epitaxy. The stability of these highly strained Si/SiGe structures upon in situ annealing has been measured by means of x-ray reflectivity (XRR) up to 830°C. The temporal evolution of XRR reciprocal space maps was recorded, and a gradual disappearance of the multilayer structure was detected after annealing for 7 h at a temperature of 790°C. From the temporal evolution of the optical constants of the layers, deduced from the simulations and fits of the specular reflectivity, we obtained an interdiffusion coefficient D = (1.01 ± 0.03) x 10 -21 m 2 s -1 at 790°C.

In this work, we present recent achievements on the low-temperature (∼300 °C) molecular beam epitaxial growth of high Ge content Si/SiGe modulation-doped multiple quantum well structures on Si 0.5 Ge 0.5 pseudosubstrates. High-resolution X-ray reflectivity and diffraction experiments performed at the Swiss Light Source synchrotron, as well as analysis by transmission electron microscopy, showed very good control of the growth parameters and interface r.m.s. roughness as low as 0.4 nm.

Si/SixGe1-x quantum well samples with various barrier and well widths as well as Ge concentrations (0.70 < x < 0.85) have been prepared by low temperature molecular beam epitaxy on relaxed buffer layers. Composition and thickness of the strain symmetrized structures are determined by transmission electron microscopy, X-ray diffraction and X-ray reflectivity. The unique set of structural parameters, determined with high accuracy in combination with polarization resolved intersubband absorption and photoluminescence spectra deduced from the same set of samples allows for a detailed comparison with k.p calculations. The observed shift of the band gap luminescence to lower energy with increasing Ge concentration in the well is found to agree very well with accepted values for the valence band offset of 0.72-0.74eV between Si and Ge pseudomorphically strained to Si 0.5 Ge 0.5 .

Low energy plasma enhanced chemical vapour deposition (LEPECVD) is a relatively new growth method, which has been used to create high quality epitaxial silicon germanium material on conventional Si(001) wafers. This material is eminently suitable for electronic devices. The best performance for n-type and p-type conduction is seen in tensile-strained Si and compressively strained Ge quantum wells, respectively. Since such quantum wells cannot be grown directly on a silicon substrate, a virtual substrate (VS) is first grown. The reactive conditions within the plasma make it possible to grow the VS at rates of up to 10 nms -1 independent of substrate temperature. The quantum wells were grown using a lower plasma intensity, at growth rates of approximately 0.3 nms -1 . The electrical properties of the material compare very well with molecular beam epitaxy (MBE) references, and hybrid material where the buffer is grown by LEPECVD and the electrically active layers are grown by MBE. In addition, the structural quality of the material is analysed by atomic force microscopy, transmission electron microscopy and defect etching.

For the design flexibility of SiGe based quantum cascade lasers high Ge composition Si/SiGe (x = 80%) superlattices are important. We present an X-ray small angle scattering and high-resolution X-ray diffraction study on strain compensated Si/Si1– x Gex multiple quantum well structures with Ge compositions (x up to 80%), grown on Si0.5Ge0.5 pseudo-substrates. To test the temperature stability of such layers occurring in processing steps, in-situ annealing X-ray reflectivity measurements were performed for temperatures up to 810 °C. From the analysis of the reflectivity data, we obtain the layer thicknesses and the interface roughness of the superlattices during annealing. Using a one dimensional diffusion equation, the Ge diffusion coefficient for these conditions was obtained. Furthermore, the strain status and Ge composition in the superlattice structure and in the SiGe buffer before and after annealing were determined from the symmetrical and asymmetrical reciprocal space maps.