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Solid-state sodium batteries are currently gaining enormous interest as a lower-cost and more environmentally friendly alternative to lithium batteries. They contain significantly less critical rare elements in both the electrolyte and the active material. However, to date, there is no efficient material combination of metallic anode, cathode, and solid electrolyte for room temperature applications that does not require an additional liquid electrolyte while maintaining high energy density. NaPSiO-based glass-ceramics show high ionic conductivity at room temperature, good corrosion resistance against ambient humidity and CO2, and stability against metallic sodium. However, the conductivity mechanisms of this promising class of materials are currently poorly understood. Herein, high frequency impedance measurements up to 108 Hz shed light on the contributions of grains and grain boundaries to the total impedance, including the distribution of relaxation time constants of the fully crystallized material. In addition, analysis of the temperature dependence allows separation of electrode contributions and determination of activation energies for grain and grain boundary conductivities. Our study provides the basis for fine-tuning the stoichiometry of NaPSiO-based glass-ceramics in terms of maximizing the conductive phase fraction to optimize the performance of future solid-state sodium batteries.

Osteomyelitis caused by S. aureus is a severe infection of the bone, typically associated with severe bone function impairment, therapeutic failure, high morbidity, invalidity, and occasionally even death. The hallmark of staphylococcal osteomyelitis is the destruction of the cortical bone structures, yet the mechanisms contributing to this pathology are hitherto poorly understood.

The uniaxial viscosity is an important material property that has to be determined in order to understand the densification of a material during the sintering process. It depends simultaneously on temperature, relative density and grain size which complicates its determination. To determine its dependence on these three factors, bending creep tests are performed on pre-sintered 3Y-TZP specimens with different relative densities and grain sizes up to the corresponding pre-sintering temperatures. The uniaxial viscosity of 3Y-TZP specimens is calculated after obtaining the deflection rates. It is found that the uniaxial viscosity decreases with temperature according to the Arrhenius equation. In addition, the tetragonal to cubic phase transformation at temperature above 1300 °C leads to a decrease of the activation energy. Apart from that, the contribution of densification and grain growth to the increase of the uniaxial viscosity is quantitatively determined. When grain boundary diffusion dominates, the contribution of grain growth is up to 1.8 times that of densification to the uniaxial viscosity. Furthermore, it is found that Rahaman's model best fits the normalized uniaxial viscosity. At the end, an evolution profile of the uniaxial viscosity for polycrystalline materials during the sintering process is proposed to facilitate the analysis of the sintering shrinkage rate.

Staphylococcus aureus can invade and persist in non-professional phagocytes, thereby escaping host defense mechanisms and antibiotic treatment. The intracellular lifestyle of S. aureus contributes to the development of infection, e.g., in infective endocarditis or chronic osteomyelitis.

The density, microstructure, and ionic conductivity of solid electrolyte Li

Dense (Hf, Ta, Nb, Ti, V)C- and (Ta, Nb, Ti, V, W)C-based high-entropy carbides (HEC) were produced by three different sintering techniques: gas pressure sintering/sinter–HIP at 1900 °C and 100 bar Ar, vacuum sintering at 2250 °C and 0.001 bar as well as SPS/FAST at 2000 °C and 60 MPa pressure. The relative density varied from 97.9 to 100%, with SPS producing 100% dense samples with both compositions. Grain size measurements showed that the substitution of Hf with W leads to an increase in the mean grain size of 5–10 times the size of the (Hf, Ta, Nb, Ti, V,)C samples. Vacuum-sintered samples showed uniform grain size distribution regardless of composition. EDS mapping revealed the formation of a solid solution with no intermetallic phases or element clustering. X-ray diffraction analysis showed the structure of mostly single-phase cubic high-entropy carbides. Hardness measurements revealed that (Hf, Ta, Nb, Ti, V)C samples possess higher hardness values than (Ta, Nb, Ti, V, W)C samples.

Several methods to isolate monocytes from whole blood have been previously published, with different advantages and disadvantages. For the purpose of cytokine release assessment upon external stimulation, the use of monocyte preparations consisting of non-activated cells is prerequisite. Affinity-isolated monocyte preparations from peripheral blood mononuclear cells (PBMCs), obtained via positive or negative selection using magnetic beads, released pro-inflammatory cytokines such as TNF-α and IL-6 even without adding external stimuli, hindering any assessment of an effect of bacterial lipoproteins on cell stimulation. Hence, the cell preparation protocol was modified by adding a quiescence step on repellent surface culture plates, dampening any monocyte pre-activation. This protocol now provides a robust method to prepare silent yet fully activatable, pure monocyte populations for further use in stimulus-elicited activation experiments.

The electrochemical alkali ion exchange is a powerful technique to synthesize novel active materials for secondary batteries or to study Li/Na/K analogous intercalation compounds. Herein, we report for the first time the electrochemically conducted exchange of Li-ions by Na-ions within the host lattice of LiCoO2. Li–Na substitution in a potential range of 2.0–4.0 ​V vs. Na/Na+ leads to the formation of a Li/Na-mixed intercalation compound. Operando XRD measurements and ex-situ EDS-mappings indicate that the different ionic radii and the corresponding CoO2-layer distances forbid Li–Na mixing in the lattice, resulting in the emergence of Na- and Li-rich domains during Na-ion insertion. Charging and discharging of the resulting Li/Na-mixed intercalation compound is dominated by Na-insertion and extraction, while Li-ions remain in the lattice until it is completely depleted of Na-ions. These novel insights concerning competitive kinetics, thermodynamics and phase evolution behavior can be highly useful to understand similarities and differences of Na- and Li-insertion chemistries to develop materials for future Na-ion batteries based on the comprehensive scientific knowledge in Li-ion technology.

New sodium-based battery concepts require solid electrolytes as ion conducting separators. Besides NaSICON and β-Al

The oxidation behavior of pure and 0.2 wt% B-containing diamond powders was investigated by thermal analysis, SEM analysis, and Raman spectroscopy of partially oxidized diamonds. Boron-doped diamond exhibited a much higher oxidation stability than that of pure diamond. The maximum oxidation rate shifted from 773 °C for the pure diamond to 1118 °C for the B-doped diamond. SEM analysis of the surface of the partially oxidized diamonds revealed that the low boron content (0.2%) was sufficient for the formation of a protective B2O3 surface layer in the regions in which active oxidation took place. This layer was most probably the reason for the improved oxidation resistance.

The Staphylococcus aureus-related complex is formed by the Staphylococcus aureus, Staphylococcus schweitzeri, Staphylococcus argenteus, Staphylococcus roterodami and Staphylococcus singaporensis. Within this complex, S. schweitzeri is the only species mainly found in African wildlife, but it is rarely detected as a colonizer in humans or as a contaminant of fomites. The few detections in humans are most likely spillover events after contact with wildlife. However, since S. schweitzeri can be misidentified as S. aureus using culture-based routine techniques, it is likely that S. schweitzeri is under-reported in humans. The low number of isolates in humans, though, is consistent with the fact that the pathogen has typical animal adaptation characteristics (e.g., growth kinetics, lack of immune evasion cluster and antimicrobial resistance); however, evidence from selected in vitro assays (e.g., host cell invasion, cell activation, cytotoxicity) indicate that S. schweitzeri might be as virulent as S. aureus. In this case, contact with animals colonized with S. schweitzeri could constitute a risk for zoonotic infections. With respect to antimicrobial resistance, all described isolates were found to be susceptible to all antibiotics tested, and so far no data on the development of spontaneous resistance or the acquisition of resistance genes such the mecA/mecC cassette are available. In summary, general knowledge about this pathogen, specifically on the potential threat it may incur to human and animal health, is still very poor. In this review article, we compile the present state of scientific research, and identify the knowledge gaps that need to be filled in order to reliably assess S. schweitzeri as an organism with global One Health implications.

The project has created new technical approaches to manufacture large size transparent ceramic windows (transparency 85% and higher in the IR part of spectrum) using advanced consolidation techniques such as 3D printing (binder jet printing of green prototypes up to 120 mm in diameter) and spark plasma sintering (enable to form domes of 70 mm in diameter).

Silicon carbide ceramics have found widespread use due to their high corrosion stability. Both solid state-sintered silicon carbide, which has an extremely high corrosion resistance, and silicon-infiltrated silicon carbide are used for various applications. The latter material contains SiC as well as free silicon, which is less stable. Hence, in the present work, the corrosion behavior of silicon-infiltrated silicon carbide ceramics was investigated in NaOH solutions. Long-term corrosion experiments were conducted, and a method for analyzing the corrosion behavior in short-term experiments was developed. The short-term method is based on the accurate measurement of the corrosion depth by laser scanning microscopy on polished surfaces. The results of both methods were in good agreement. The advantage of the short-term method is that it provides information on changes in corrosion mechanisms and corrosion rates in the initial period and as a function of the impurities present. Preferential corrosion of Si at the interface to SiC was observed. TEM investigations revealed that this enhanced corrosion was caused by the segregation of impurities.

Nukleinsaure-Amplifikations-Techniken (NAT), wie die PCR, sind hochsensitiv sowie selektiv und stellen in der mikrobiologischen Diagnostik wertvolle Erganzungen zur kulturellen Anzucht und Serologie dar. Sie bergen aber gerade bei formalinfixiertem und in Paraffin eingebettetem Gewebe ein Risiko fur sowohl falsch negative als auch falsch positive Resultate, welches nicht immer richtig eingeschatzt wird. Daher haben Vertreter der Deutschen Gesellschaft fur Hygiene und Mikrobiologie (DGHM) und der Deutschen Dermatologischen Gesellschaft (DDG) einen Konsensus in Form einer Ubersichtsarbeit erarbeitet, wann eine NAT am Paraffinschnitt angezeigt und sinnvoll ist und welche Punkte dabei in der Praanalytik und Befundinterpretation beachtet werden mussen. Da bei Verdacht auf eine Infektion grundsatzlich Nativgewebe genutzt werden soll, ist die PCR am Paraffinschnitt ein Sonderfall, wenn beispielsweise bei erst nachtraglichaufgekommenem Verdacht auf eine Infektion kein Nativmaterial zur Verfugung steht und nicht mehr gewonnen werden kann. Mogliche Indikationen sind der histologisch erhobene Verdacht auf eine Leishmaniose, eine Infektion durch Bartonellen oder Rickettsien, oder ein Ecthyma contagiosum. Nicht sinnvoll ist oder kritisch gesehen wird eine NAT am Paraffinschnitt zum Beispiel bei Infektionen mit Mykobakterien oder RNA-Viren. Die Konstellation fur eine NAT aus Paraffingewebe sollte jeweils benannt werden, die erforderliche Pra-Analytik, die jeweiligen Grenzen des Verfahrens und die diagnostischen Alternativen bekannt sein. Der PCR-Befund sollte entsprechend kommentiert werden, um Fehleinschatzungen zu vermeiden.

Diamond-silicon nitride composite materials with 40 vol% of diamond with two different grain sizes (50 µm and 100 µm) were produced using the field-assisted sintering technique/spark plasma sintering (FAST/SPS). A diamond powder with a SiC coating was also used. For the pure matrix material and the composites, the microstructure and the wear behavior under dry oscillating sliding conditions were investigated with use of steel and silicon nitride balls as counter-body materials. The composite materials showed coefficients of friction (COFs) of as low as 0.1, substantially lower than the COFs (0.8–1.2) obtained for the matrix. The highest wear resistance (wear rate: 8*10-8 mm³/Nm) was observed for the composite material with the SiC-coated diamond particles due to the stronger bonding of the diamond particles to the matrix in this material.

Nucleic acid amplification techniques (NATs), such as PCR, are highly sensitive and specific methods that have become valuable supplements to culture and serology in the diagnosis of infectious disorders. However, especially when using formalin-fixed and paraffin-embedded tissue, these techniques are associated with both false-negative and false-positive results, a pitfall that is frequently misjudged. Representatives of the German Society of Hygiene and Microbiology (DGHM) and the German Society of Dermatology (DDG) therefore set out to develop a consensus - in the form of a review article - on the appropriate indications for NATs using paraffin-embedded tissue, its contraindications, and the key points to be considered in the pre- and post-analytical phase. Given that fresh, naive tissue is preferably to be used in the workup of a suspected infection, PCR analysis on paraffin sections represents an exception. The latter may be considered if an infection is suspected at a later point in time and fresh tissue has not been preserved or can no longer be obtained. Potential indications include confirmation of histologically suspected infections with Leishmania spp., Bartonella spp., Rickettsia spp., or in case of ecthyma contagiosum. Infections with, for example, mycobacteria or RNA viruses, on the other hand, are not considered useful indications for NATs using paraffin sections. In order to avoid misinterpretation of test results, it is essential that laboratory reports on NATs using paraffin-embedded tissue contain information on the indication/diagnostic circumstances, the required and chosen pre-analytical steps, the limitations of the method, and on diagnostic alternatives.

High quality α/β-Sialon materials were reproducible prepared using cost effective silicon nitride powders and an aqueous processing route. The influence of the powder quality (SN-E10, Silzot HQ, SicoNide P95H) on sintering and phase formation was investigated. With all 3 powders dense Sialon materials with nominal composition RxSi12-(m + n)Alm + nOnN16-n and m = 0.5 and n = 1 and 4 wt% excess rare earth additives could be prepared. The material based on Silzot HQ exhibits the highest α-Sialon content and subsequently the highest hardness due to the lower oxygen content of the starting powder. The microstructural analysis using XRD, FESEM including EDX- and EBSD-mapping reveal, that the α-Sialon grains are formed on existing α-Si3N4 grains of the starting powder. Anisotropic grain growth of the α-Sialon takes place therefore the differences in the microstructure depend strongly on the oxygen content but not from the α/β-content of the starting powders.

Stool-based rapid diagnostic tests (RDTs) for pathogenic intestinal protozoa (e.g. Cryptosporidium spp. and Giardia intestinalis) allow for prompt diagnosis and treatment in resource-constrained settings. Such RDTs can improve individual patient management and facilitate population-based screening programmes in areas without microbiological laboratories for confirmatory testing. However, RDTs are difficult to interpret in case of 'trace' results with faint test band intensities and little is known about whether such ambiguous results might indicate 'true' infections. In a longitudinal study conducted in poor neighbourhoods of Port Elizabeth, South Africa, a total of 1428 stool samples from two cohorts of schoolchildren were examined on the spot for Cryptosporidium spp. and G. intestinalis using an RDT (Crypto/Giardia DuoStrip; Coris BioConcept). Overall, 121 samples were positive for G. intestinalis and the RDT suggested presence of cryptosporidiosis in 22 samples. After a storage period of 9-10 months in cohort 1 and 2-3 months in cohort 2, samples were subjected to multiplex PCR (BD Max™ Enteric Parasite Panel, Becton Dickinson). Ninety-three percent (112/121) of RDT-positive samples for G. intestinalis were confirmed by PCR, with a correlation between RDT test band intensity and quantitative pathogen load present in the sample. For Cryptosporidium spp., all positive RDTs had faintly visible lines and these were negative on PCR. The performance of the BD Max™ PCR was nearly identical in both cohorts, despite the prolonged storage at disrupted cold chain conditions in cohort 1. The Crypto/Giardia DuoStrip warrants further validation in communities with a high incidence of diarrhoea.

Staphyloccocus aureus is a major human pathogen and a common cause for superficial and deep seated wound infections. The pathogen is equipped with a large arsenal of virulence factors, which facilitate attachment to various eukaryotic cell structures and modulate the host immune response. One of these factors is the extracellular adherence protein Eap, a member of the “secretable expanded repertoire adhesive molecules” (SERAM) protein family that possesses adhesive and immune modulatory properties. The secreted protein was previously shown to impair wound healing by interfering with host defense and neovascularization. However, its impact on keratinocyte proliferation and migration, two major steps in the re-epithelialization process of wounds, is not known. Here, we report that Eap affects the proliferation and migration capacities of keratinocytes by altering their morphology and adhesive properties. In particular, treatment of non-confluent HaCaT cell cultures with Eap resulted in cell morphology changes as well as a significant reduction in cell proliferation and migration. Eap-treated HaCaT cells changed their appearance from an oblong via a trapezoid to an astral-like shape, accompanied by decreases in cell volume and cell stiffness, and exhibited significantly increased cell adhesion. Eap had a similar influence on endothelial and cancer cells, indicative for a general effect of Eap on eukaryotic cell morphology and functions. Specifically, Eap was found to interfere with growth factor-stimulated activation of the mitogen-activated protein kinase (MAPK) pathway that is known to be responsible for cell shape modulation, induction of proliferation and migration of epithelial cells. Western blot analyses revealed that Eap blocked the phosphorylation of extracellular signal-regulated kinase 1 and 2 (Erk1/2) in keratinocyte growth factor (KGF)-stimulated HaCaT cells. Together, these data add another antagonistic mechanism of Eap in wound healing, whereby the bacterial protein interferes with keratinocyte migration and proliferation.

There is no agreement about the frequency of nosocomial infections and infections caused by multidrug resistant organisms (MDRO) in Germany. The aim of this review is to generate updated estimates of the national burden of these infections and to discuss them in an international context. The most important sources of this analysis are the data of the national prevalence studies conducted in various European countries and in the U.S. It can be assumed that there are between 400,000 and 600,000 patients with nosocomial infections each year in Germany. The mortality attributable to them is between 6000 and 15,000 patients. About 30,000 to 35,000 patients develop nosocomial infections caused by MDRO. Currently there are no robust data how many patients die each year because of MDRO infections. According to the best available estimate, the annual number may be between 1000 and 4000 cases. The problems of nosocomial infections and the increase of antimicrobial resistance are highly relevant and should not be belittled. However, an overestimation of this dangerous trend may lead to inappropriate use of limited resources.

Spark Plasma Sintering (SPS) of silicon nitride is affected by temperature non-uniformities within the powder compact, resulting in density and microstructure inhomogeneities. A double-pyrometer experimental setup reveals a temperature disparity of 100-200° C between the overheated outer surface of the die and the bottom of the upper punch, as a consequence of the electric current concentration through the die's wall characterizing the SPS of non-conductive powders utilizing conventional SPS tooling. A novel tooling design, consisting in the tailored drilling of axial cylindrical or ring-shaped holes within the punch, is individuated and optimized through a campaign of fully-coupled thermal, electrical and mechanical finite element simulations. The analysis of the numerical results, experimentally assessed, allows for a comprehensive understanding of the phenomena underlying radial temperature distributions in SPS and leads to the development of a technological solution for the uniformization of temperature distribution.

Multi-wire sawing has emerged as the leading technology in wafer production for a variety of semiconductor materials. This study investigates the process stability and efficiency of conventional semiconductor multi-wire slurry saws in routinely machining translucent, high-density alumina ceramics. The brittle and fine-grained translucent alumina ceramics with extreme hardness and wear resistance represents a major challenge for the process. The alumina ceramic substrates are used for sensor applications, energy storage technology and applications in power electronics. An ideal adaptation of the sawing process parameters to the workpiece properties guarantees the efficiency of the slurry sawing process and the quality of the ceramic wafers. An indicator of the efficiency and cutting ability of the sawing process is the size of the bow of the wire web. The first time was shown that the wire bow can be used for the characterization of the sawing processes for hard and brittle technical ceramics. It was found that a longer workpiece length, a higher number of wafers and stronger abrasive wear lead to an increased size of the bow. The rocking frequency has no measurable influence on the size of the bow. Knowledge of these relations is an extremely valuable tool in the sawing process development for hard and brittle technical ceramics.

Purpose: The incidence of Staphylococcus aureus skin and soft tissue infection (SSTI) is high in sub-Saharan Africa. This is fueled by a high prevalence of Panton-Valentine leukocidin (PVL), which can be associated with necrotizing disease. The aim was to describe the clinical presentation and the treatment of SSTI in the African setting and to identify challenges in the management. Methods: Patients (n = 319) were recruited in DR Congo (n = 56, 17.6%), Gabon (n = 89, 27.9%), Mozambique (n = 79, 24.8%) and Tanzania (n = 95, 29.8%) during the prospective observational StaphNet cohort study (2010–2015). A physician recorded the clinical management in standardized questionnaires and stratified the entity of SSTI into superficial (sSSTI) or deep-seated (dSSTI). Selected virulence factors (PVL, β hemolysin) and multilocus sequence types (MLST) were extracted from whole genome sequencing data. Results: There were 220/319 (69%) sSSTI and 99/319 (31%) dSSTI. Compared to sSSTI, patients with dSSTI were more often hospitalized (13.2 vs. 23.5%, p = 0.03), HIV-positive (7.6 vs. 15.9%, p = 0.11), and required more often incision and drainage (I&D, 45.5 vs. 76.5%, p = 0.04). The proportion of an adequate antimicrobial therapy increased marginally from day 1 (empirical therapy) to day 3 (definite therapy), for sSSTI (70.7 to 72.4%) and dSSTI (55.4 to 58.9%). PVL was a risk factor for I&D (OR = 1.7, p = 0.02) and associated with MLST clonal complex CC121 (OR = 2.7, p < 0.001). Conclusion: Appropriate antimicrobial agents and surgical services to perform I&D were available for the majority of patients. Results from susceptibility testing should be considered more efficiently in the selection of antimicrobial therapy.

Neben oxydischen Feuerfestwerkstoffen, die zurzeit fur die Auskleidung von Vergasungsreaktoren genutzt werden, sind Siliciumcarbid (SiC)- und Aluminiumnitrid (AlN)-Keramiken mogliche erfolgversprechende Alternativen fur Feuerfestanwendungen unter reduzierenden Bedingungen wie sie in Vergasungsreaktoren vorhanden sind. Daher wurden AlN-Werkstoffe mit unterschiedlichen Sinteradditiven, rekristallisierte SiC-Werkstoffe (RSiC) und auch RSiC-Werkstoffe, die mit Kohlenstoff und Zirkoniumdioxid infiltriert wurden, hergestellt und ihr Korrosionsverhalten im Kontakt mit verschiedenen Aschen getestet. Die Ergebnisse zeigten, dass die RSiC-Werkstoffe und besonders die infiltrierten RSiC-Werkstoffe eine extrem hohe Stabilitat sowohl gegenuber sauren als auch basischen Aschen aufweisen. Modifizierte RSiC-Werkstoffe haben daher ein hohes Potential fur Feuerfestanwendungen in verschiedenen Atmospharen.

Although Clostridium difficile is a major cause of diarrhoea, its epidemiology in tropical settings is poorly understood. Strain characterisation requires work-up in specialised laboratories, often after prolonged storage without properly maintained cold chain.; We screened 298 human faecal samples from Cote d'Ivoire using a rapid test for C. difficile glutamate dehydrogenase (GDH). GDH-positive samples were aerobically stored at disrupted cold chain conditions (mean duration: 11 days) before transfer to a reference laboratory for anaerobic culture, susceptibility testing, PCR assays and ribotyping.; Sixteen samples (5.4%) had a positive GDH screening test. C. difficile infection was confirmed in six specimens by culture and PCR, while no nucleic acids of C. difficile were detected in the culture-negative samples. Further analysis of stool samples harbouring toxigenic C. difficile strains confirmed that both GDH and toxins remained detectable for at least 28 days, regardless of storage conditions (aerobic storage at 4°C or 20°C).; Storage conditions only minimally affect recovery of C. difficile and its toxins in stool culture. A rapid GDH screening test and subsequent transfer of GDH-positive stool samples to reference laboratories for in-depth characterisation may improve our understanding of the epidemiology of C. difficile in the tropics.

Staphylococcus aureus is a major cause of nosocomial and community-acquired infections. The success of S. aureus as a pathogen is due in part to its many virulence determinants and resistance to antimicrobials. In particular, methicillin-resistant S. aureus has emerged as a major cause of infections and led to increased use of the antibiotics vancomycin and daptomycin, which has increased the isolation of vancomycin-intermediate S. aureus and daptomycin-nonsusceptible S. aureus strains. The most common mechanism by which S. aureus acquires intermediate resistance to antibiotics is by adapting its physiology and metabolism to permit growth in the presence of these antibiotics, a process known as adaptive resistance. To better understand the physiological and metabolic changes associated with adaptive resistance, six daptomycin-susceptible and -nonsusceptible isogenic strain pairs were examined for changes in growth, competitive fitness, and metabolic alterations. Interestingly, daptomycin nonsusceptibility coincides with a slightly delayed transition to the postexponential growth phase and alterations in metabolism. Specifically, daptomycin-nonsusceptible strains have decreased tricarboxylic acid cycle activity, which correlates with increased synthesis of pyrimidines and purines and increased carbon flow to pathways associated with wall teichoic acid and peptidoglycan biosynthesis. Importantly, these data provided an opportunity to alter the daptomycin nonsusceptibility phenotype by manipulating bacterial metabolism, a first step in developing compounds that target metabolic pathways that can be used in combination with daptomycin to reduce treatment failures.

Silicon carbide ceramics have found widespread use due to their high corrosion stability. Nevertheless, under certain conditions electrochemical corrosion is observed. Hence, in the present work a SiSiC ceramic and a composite material containing SiC as well as free carbon and Si were investigated in terms of microstructure and electrochemical corrosion behaviour. The SiC grains in the SiSiC exhibited a core-rim structure. The core and rim were formed from primary and secondary SiC, respectively, and had different corrosion stabilities due to the higher electrical conductivity of the rim. In contrast to the behaviour observed with pure chemical corrosion, under electrochemical conditions the Si showed a higher stability than the SiC in NaOH. Also, thicker protective SiO2 layers were formed in H2SO4 on the SiC grains than on the Si grains.

A combined experimental and numerical study is conducted to investigate temperature nonhomogeneities within a Spark Plasma Sintering tooling setup. Radial thermal gradients through a powder compact are encountered, a cause of microstructural nonuniformities in sintered specimens, which tend to become more significant when increasing the setup's characteristic size. In the insulating silicon nitride powder compact employed for the experimental procedures, a double pyrometer arrangement detects a strong temperature disparity between the overheated die and the area adjacent to the tooling's axis. A previous finite-element simulations campaign had individuated a possible solution in a novel punch design, consisting in the drilling of three concentric ring-shaped holes according to a specific geometrical pattern, whose efficacy is here experimentally verified. Further punch optimization strategies are drawn, involving a refinement of the three-rings geometry by linearly varying the drilled holes characteristic dimensions along the radial direction, or the selective coating and consequent insulation of the punch cross section with a thin layer of hexagonal boron nitride. Ideal configurations are identified, consisting in a concentration of the graphite punch's mass at its center by means of a tailored holes pattern, or in the coating of a portion of the conventionally shaped punch with boron nitride.

Objective.To establish the source and contamination routes resulting in positive clinical and surveillance microbiological cultures with carbapenem-resistant, GIM-1 metallo-β-lactamase–positiveAcinetobacter pitiiandAcinetobacter radioresistensfrom 21 patients in 8 departmentsDesign.Retrospective, descriptive study.Setting.A 1,300-bed tertiary care academic medical facility consisting of 90 buildings linked by a pneumatic transport system (PTS).Methods.Microbiological workup of the cluster strains included matrix-assisted laser desorption/ionization time-of-flight species identification, phenotypic carbapenemase tests, polymerase chain reaction–based genotyping of carbapenemase, and pulsed-field gel electrophoresis. Outbreak management procedures were employed according to institutional regulations.Results.The rarity of GIM-1Acinetobacterspecies in the hospital and region, the lack of epidemiological links between patients, and the fact that in some patients the apparent colonization was clearly nonnosocomial prompted the suspicion of a pseudo-outbreak. Numerous environmental cultures were positive for GIM-1-positiveAcinetobacter(including archived sample requisition forms, PTS capsules, cultures from line-diverter and dispenser stations, and sterilized transport capsules following PTS delivery). Moreover, it was observed that condensation fluid from subterranean PTS tubing resulted in water entry in PTS capsules, possibly conferring specimen contamination. After extensive system disinfection, environmental surveys of the PTS were negative, and no further positive patient specimens were encountered.Conclusions.This is the first report of a PTS-associated pseudo-outbreak. The large number of falsely positive patient-related specimens in conjunction with the potential hazard of airborne and contact spread of multidrug-resistant microorganisms (in this case, GIM-1 carbapenem-resistantAcinetobacterspecies) underscores the need for implementation of infection control–based monitoring and operating procedures in a hospital PTS.

Nucleic acid amplification techniques (NATs), such as PCR, are highly sensitive and specific methods that have become valuable supplements to culture and serology in the diagnosis of infectious disorders. However, especially when using formalin-fixed and paraffin-embedded tissue, these techniques are associated with both false-negative and false-positive results, a pitfall that is frequently misjudged. Representatives of the German Society of Hygiene and Microbiology (DGHM) and the German Society of Dermatology (DDG) therefore set out to develop a consensus - in the form of a review article - on the appropriate indications for NATs using paraffin-embedded tissue, its contraindications, and the key points to be considered in the pre- and post-analytical phase. Given that fresh, naive tissue is preferably to be used in the workup of a suspected infection, PCR analysis on paraffin sections represents an exception. The latter may be considered if an infection is suspected at a later point in time and fresh tissue has not been preserved or can no longer be obtained. Potential indications include confirmation of histologically suspected infections with Leishmania spp., Bartonella spp., Rickettsia spp., or in case of ecthyma contagiosum. Infections with, for example, mycobacteria or RNA viruses, on the other hand, are not considered useful indications for NATs using paraffin sections. In order to avoid misinterpretation of test results, it is essential that laboratory reports on NATs using paraffin-embedded tissue contain information on the indication/diagnostic circumstances, the required and chosen pre-analytical steps, the limitations of the method, and on diagnostic alternatives.

Nukleinsäure-Amplifikations-Techniken (NAT), wie die PCR, sind hochsensitiv sowie selektiv und stellen in der mikrobiologischen Diagnostik wertvolle Ergänzungen zur kulturellen Anzucht und Serologie dar. Sie bergen aber gerade bei formalinfixiertem und in Paraffin eingebettetem Gewebe ein Risiko für sowohl falsch negative als auch falsch positive Resultate, welches nicht immer richtig eingeschätzt wird. Daher haben Vertreter der Deutschen Gesellschaft für Hygiene und Mikrobiologie (DGHM) und der Deutschen Dermatologischen Gesellschaft (DDG) einen Konsensus in Form einer Übersichtsarbeit erarbeitet, wann eine NAT am Paraffinschnitt angezeigt und sinnvoll ist und welche Punkte dabei in der Präanalytik und Befundinterpretation beachtet werden müssen. Da bei Verdacht auf eine Infektion grundsätzlich Nativgewebe genutzt werden soll, ist die PCR am Paraffinschnitt ein Sonderfall, wenn beispielsweise bei erst nachträglichaufgekommenem Verdacht auf eine Infektion kein Nativmaterial zur Verfügung steht und nicht mehr gewonnen werden kann. Mögliche Indikationen sind der histologisch erhobene Verdacht auf eine Leishmaniose, eine Infektion durch Bartonellen oder Rickettsien, oder ein Ecthyma contagiosum. Nicht sinnvoll ist oder kritisch gesehen wird eine NAT am Paraffinschnitt zum Beispiel bei Infektionen mit Mykobakterien oder RNA-Viren. Die Konstellation für eine NAT aus Paraffingewebe sollte jeweils benannt werden, die erforderliche Prä-Analytik, die jeweiligen Grenzen des Verfahrens und die diagnostischen Alternativen bekannt sein. Der PCR-Befund sollte entsprechend kommentiert werden, um Fehleinschätzungen zu vermeiden.

Clonal clusters and gene repertoires of Staphylococcus aureus are essential to understand disease and are well characterized in industrialized countries but poorly analysed in developing regions. The objective of this study was to compare the molecular-epidemiologic profiles of S. aureus isolates from Sub-Saharan Africa and Germany. S. aureus isolates from 600 staphylococcal carriers and 600 patients with community-associated staphylococcal disease were characterized by DNA hybridization, clonal complex (CC) attribution, and principal component (PCA)-based gene repertoire analysis. 73% of all CCs identified representing 77% of the isolates contained in these CCs were predominant in either African or German region. Significant differences between African versus German isolates were found for alleles encoding the accessory gene regulator type, enterotoxins, the Panton-Valentine leukocidin, immune evasion gene cluster, and adhesins. PCA in conjunction with silhouette analysis distinguished nine separable PCA clusters, with five clusters primarily comprising of African and two clusters of German isolates. Significant differences between S. aureus lineages in Africa and Germany may be a clue to explain the apparent difference in disease between tropical/(so-called) developing and temperate/industrialized regions. In low-resource countries further clinical-epidemiologic research is warranted not only for neglected tropical diseases but also for major bacterial infections.

Background: The emergence of community-acquired Staphylococcus aureus infections is increasingly recognized as life threating problem worldwide. In Manhiça district, southern Mozambique, S. aureus is the leading cause of community-acquired bacteremia in neonates. Methods: Eighty-four S. aureus isolates from children less than 5 years admitted to Manhiça District Hospital from 2001 to 2009 were randomly selected and genetically characterized by DNA microarray and spa typing. Antimicrobial susceptibility was determined by VITEK 2. Results: Thirty-eight different spa types and 14 clonal complexes (CC) were identified. Spa-type t084 (n = 10; 12%) was the most predominant while CC8 (n = 18; 21%) and CC15 (n = 14; 16%) were the most frequent CCs. Mortality tended to be higher among children infected with CC45 (33.3%, 1/3) and CC8 (27.8%, 5/18). The majority of isolates possessed the accessory gene regulator I (45%) and belonged to either capsule type 8 (52%) or 5 (47%). Panton valentine leukocidin (PVL) encoding genes were detected in 30%. Antibiotic resistance was high for penicillin (89%), tetracycline (59%) and Trimethoprim Sulfamethoxazole (36%) while MRSA was uncommon (8%). Conclusions: Although MRSA were uncommon, we found high genetic diversity of methicillin susceptible S. aureus causing bacteremia in Mozambican children, associated with high resistance to the most available antibiotics in this community. Some CCs are likely to be more lethal indicating the need for prompt recognition and appropriate treatment.

Livestock-associated methicillin-resistant Staphylococcus aureus (LA-MRSA) of the clonal complex (CC) 398 became primarily known as colonizers of livestock animals. In the past few years, they have been increasingly introduced into hospitals with subsequent emergence of human infections. However, the (re-)adaptation to the human host is only incompletely understood. This study aimed to assess virulence properties of LA-MRSA CC398 by functional modeling of infection and colonization processes. A selection of 15 human LA-MRSA CC398 isolates and 11 pig-colonizing isolates were characterized regarding their virulence capacities and compared with human isolates of hospital-acquired (HA)-MRSA (CC5, CC22 and CC45) and community-associated (CA)-MRSA (CC8, CC30 and CC80) clonal lineages. Our investigations demonstrated that LA-MRSA CC398 adhered less efficient to human cells and human/bovine plasma fibronectin than CA-MRSA and HA-MRSA isolates. In contrast, the LA-MRSA CC398 isolates revealed a high cytotoxic potential comparable to certain CA-MRSA. Comparing the most prevalent LA-MRSA CC398 spa types (t011, t034, t108), isolates associated with spa t108 showed an increased adhesive and invasive potential paired with an increased ability to evade phagocytosis. The results underline both the pathogenic potential of LA-MRSA in general and the heterogeneity within the CC398 clade regarding the virulence characteristics of CC398 subpopulations. Assuming an ongoing (re-)adaptation to the human host combined with a huge reservoir of LA-MRSA CC398 in livestock and constant zoonotic transmission, the LA-MRSA CC398 lineage has the potential to pose a serious threat to human health.

The corrosion behaviour of the relatively new silicon carbide bonded diamond materials (ScD) was investigated in NaOH, H2SO4 and hydrothermal conditions and compared with that of conventional SSiC and SiSiC-materials. The corrosion resistance increases with decreasing diamond grain size. In H2SO4 all investigated materials show a very high corrosion resistance, whereas in NaOH and under hydrothermal conditions above 100 °C some leaching of residual silicon takes place. Nevertheless the fine grained ScD material exhibits a residual strength of 400 MPa after 200 h corrosion in NaOH at 90 °C. Under the same conditions the strength of the SiSiC-material reduces to 50 MPa. The silicon carbide-diamond composites demonstrate corrosion resistance superior to SiSiC and wear properties analogous to that of conventional superhard materials. This material would therefore be suitable for use in demanding corrosive wear applications.

We have used atomic-force microscopy (AFM) to probe the effect of peptidoglycan crosslinking reduction on the elasticity of the Staphylococcus aureus cell wall, which is of particular interest as a target for antimicrobial chemotherapy. Penicillin-binding protein 4 (PBP4) is a nonessential transpeptidase, required for the high levels of peptidoglycan crosslinking characteristic of S. aureus. Importantly, this protein is essential for β-lactam resistance in community-acquired, methicillin-resistant S. aureus (MRSA) strains but not in hospital-acquired MRSA strains. Using AFM in a new mode for recording force/distance curves, we observed that the absence of PBP4, and the concomitant reduction of the peptidoglycan crosslinking, resulted in a reduction in stiffness of the S. aureus cell wall. Importantly, the reduction in cell wall stiffness in the absence of PBP4 was observed both in community-acquired and hospital-acquired MRSA strains, indicating that high levels of peptidoglycan crosslinking modulate the overall structure and mechanical properties of the S. aureus cell envelope in both types of clinically relevant strains. Additionally, we were able to show that the applied method enables the separation of cell wall properties and turgor pressure.

Sintered silicon carbide ceramics have found widespread use due to their high corrosion stability. This corrosion stability can be affected by electrochemical processes. Electrochemical corrosion experiments conducted on an SSiC material in NaOH at different voltages and subsequent detailed investigation of the formed surfaces were carried out. Systematic local measurement of the corrosion rate was carried out using the AFM technique. The results revealed the recession of the SiC grain surfaces under anodic electrochemical loading, with the extents differing strongly from grain to grain. The recession rates were not found to correlate with the SiC grain orientations or polytypes. Rather, the data and the observed microstructure indicated that the behaviour was caused by variations in the resistivities of the grain boundaries.

A superplastic deformation of pre-sintered Si3N4-based nanocrystalline ceramics and Si3N4 nano-whisker reinforced composites has been investigated. Superplastic deformation tests have been carried out in the temperature range from 1500 to 1600 °C under 56 kN compression in nitrogen. During the tests, all nano-composites exhibited high rates of deformation (1.6–5.4×10−3 s−1) corresponding to high activation energy in the range of 538–699 kJ/mol. The composites enhanced by Si3N4 nano-whiskers exhibited the formation of anisotropic microstructure with anisotropic mechanical properties. The highest Vickers hardness ~19 GPa and lowest coefficient of dry wear 0.39 was exhibited by the TiN–Si3N4 nano-composite.

Field‐assisted sintering technology/Spark plasma sintering is a low voltage, direct current (DC) pulsed current activated, pressure‐assisted sintering, and synthesis technique, which has been widely applied for materials processing in the recent years. After a description of its working principles and historical background, mechanical, thermal, electrical effects in FAST/SPS are presented along with the role of atmosphere. A selection of successful materials development including refractory materials, nanocrystalline functional ceramics, graded, and non‐equilibrium materials is then discussed. Finally, technological aspects (advanced tool concepts, temperature measurement, finite element simulations) are covered.

The galvanic corrosion risk of metal/SiC-based ceramic coupling in 3.5 wt% NaCl aqueous solution is investigated. Electrochemical measurements as linear sweep voltammetry and galvanic corrosion tests according to DIN-50919 were used. The results clearly show that the resistivity of the SiC-based ceramic plays the key role in the understanding of galvanic corrosion between metal and ceramic. In all cases the ceramic represents the cathodic site of the coupling. The corrosion rate is dominated by the electrical resistance of the ceramic.

Sintered silicon carbide materials have found widespread use due to their high corrosion stability. This corrosion stability can be affected by electrochemical processes. Electrochemical corrosion experiments conducted on a SSiC material in H 2 SO 4 at different voltages and subsequent detailed investigation of the formed surfaces was carried out. The first time a systematic local measurement of the thickness of the oxide layers was carried out. The measurements revealed the formation of SiO 2 surface layers with thickness up to 125 μm. The measured values also showed a strong deviation from grain to grain. The thickness of the layers does not correlate with the crystallographic orientation of the grains or the SiC-polytypes. The data indicate that the behaviour is caused by the variation of the resistivity of the grain boundaries. The measured thicknesses as a function of the electrical charge transferred indicate that the electrochemical oxidation results in the SiO 2 and carbon dioxide.

Boron suboxide (B 6 O) based materials containing TiB 2 additions were produced in this study via two routes (non-reactive and reactive sintering) and were consolidated using a hot press, which was operated between the temperatures of 1800–1900 °C and at an applied pressure of 50 MPa for 20 min dwelling time. Relationships between the formed phases, microstructures and mechanical properties of the sintered materials were established. The density was higher in the reactive sintered materials with finer microstructure than in the non-reactive sintered counterpart. Generally, the mechanical properties of the B 6 O–TiB 2 materials were enhanced when compared to the pure B 6 O material.

New high-efficiency gasification reactors with higher temperatures and pressures and with different temperature cycles than previously require new types of refractory linings. Besides the oxide materials currently in use, SiC ceramics show great promise as refractories in the reducing atmospheres found in gasifiers. The behaviour of RSiC and SSiC materials was investigated in a flowing CO/H 2 -containing Ar atmosphere with three different ashes (from basic to strongly acidic) in the temperature range between 1000 °C and 1300 °C. After dwell times of up to 100 h the cross sections of the materials were analysed by SEM and EDS. The results showed the high stability of the materials in all ashes. The porous RSiC materials showed small amounts of infiltration depending on the ash composition, but no destruction of the necks between the SiC grains was observed. Thermodynamic calculations simulating the conditions prevailing in a gasification reactor yielded similar phases to those obtained in the corrosive conditions used in the experiments. Due to the strongly reducing conditions the sulphates in the starting ashes reduced to sulphides of much lower corrosion activity

Several (Ti,Ta)(C,N) cermets were prepared from Ti(C,N) and Ta powder with or without Ni. For comparison, Ti(C,N) with Ni were also prepared. The mixed powders were sintered at 1400–1500 °C by FAST/SPS up to a density higher than 99% theoretical density. The addition of Ta delays densification of Ti(C,N)-Ni cermets due to the formation of intermetallic phases. During sintering, the Ta was incorporated into the Ti(C,N), forming solid solution, thus changing the core-rim structure of the Ti(C,N) cermets. On the other hand, the Ta additions result in grain refinement and improved hardness (from 16.1 GPa to 17.8 GPa) and fracture toughness (from 5.5 MPa.m 1/2 to 6.9 MPa.m 1/2 ).

Mycobacterium chimaera, a non-tuberculous mycobacterium, was recently identified as causative agent of deep-seated infections in patients who had previously undergone open-chest cardiac surgery. Outbreak investigations suggested an aerosol-borne pathogen transmission originating from water contained in heater-cooler units (HCUs) used during cardiac surgery. Similar thermoregulatory devices are used for extracorporeal membrane oxygenation (ECMO) and M. chimaera might also be detectable in ECMO treatment settings. We performed a prospective microbiological study investigating the occurrence of M. chimaera in water from ECMO systems and in environmental samples, and a retrospective clinical review of possible ECMO-related mycobacterial infections among patients in a pneumological intensive care unit. We detected M. chimaera in 9 of 18 water samples from 10 different thermoregulatory ECMO devices; no mycobacteria were found in the nine room air samples and other environmental samples. Among 118 ECMO patients, 76 had bronchial specimens analysed for mycobacteria and M. chimaera was found in three individuals without signs of mycobacterial infection at the time of sampling. We conclude that M. chimaera can be detected in water samples from ECMO-associated thermoregulatory devices and might potentially pose patients at risk of infection. Further research is warranted to elucidate the clinical significance of M. chimaera in ECMO treatment settings.

The tricarboxylic acid cycle (TCA cycle) is a central metabolic pathway that provides energy, reducing potential, and biosynthetic intermediates. In Staphylococcus aureus, TCA cycle activity is controlled by several regulators (e.g. CcpA, CodY, and RpiRc) in response to the availability of sugars, amino acids, and environmental stress. Developing a bioinformatic search for additional carbon catabolite-responsive regulators in S. aureus, we identified a LysR-type regulator, catabolite control protein E (CcpE), with homology to the Bacillus subtilis CcpC regulator. Inactivation of ccpE in S. aureus strain Newman revealed that CcpE is a positive transcriptional effector of the first two enzymes of the TCA cycle, aconitase (citB) and to a lesser extent citrate synthase (citZ). Consistent with the transcriptional data, aconitase activity dramatically decreased in the ccpE mutant relative to the wild-type strain. The effect of ccpE inactivation on citB transcription and the lesser effect on citZ transcription were also reflected in electrophoretic mobility shift assays where CcpE bound to the citB promoter but not the citZ promoter. Metabolomic studies showed that inactivation of ccpE resulted in increased intracellular concentrations of acetate, citrate, lactate, and alanine, consistent with a redirection of carbon away from the TCA cycle. Taken together, our data suggest that CcpE is a major direct positive regulator of the TCA cycle gene citB.