117 research outputs found
The Phase composition and microstructure of AlÏCoCrFeNiTi alloys for the development of high-entropy alloy systems
Alloying aluminum offers the possibility of creating low-density high-entropy alloys (HEAs). Several studies that focus on the system AlCoCrFeNiTi differ in their phase determination. The effect of aluminum on the phase composition and microstructure of the compositionally complex alloy (CCA) system AlxCoCrFeNiTi was studied with variation in aluminum content (molar ratios x = 0.2, 0.8, and 1.5). The chemical composition and elemental segregation was measured for the different domains in the microstructure. The crystal structure was determined using X-ray diffraction (XRD) analysis. To identify the spatial distribution of the phases found with XRD, phase mapping with associated orientation distribution was performed using electron backscatter diffraction. This made it possible to correlate the chemical and structural conditions of the phases. The phase formation strongly depends on the aluminum content. Two different body-centered cubic (bcc) phases were found. Texture analysis proved the presence of a face-centered cubic (fcc) phase for all aluminum amounts. The hard η-(Ni, Co)3Ti phase in the x = 0.2 alloy was detected via metallographic investigation and confirmed via electron backscatter diffraction. Additionally, a centered cluster (cc) with the A12 structure type was detected in the x = 0.2 and 0.8 alloys. The correlation of structural and chemical properties as well as microstructure formation contribute to a better understanding of the alloying effects concerning the aluminum content in CCAs. Especially in the context of current developments in lightweight high-entropy alloys (HEAs), the presented results provide an approach to the development of new alloy systems
Anodisation of Aluminium Alloys by Micro-Capillary Technique as a Tool for Reliable, Cost-Efficient, and Quick Process Parameter Determination
Anodisation is essential for improving surface properties of aluminium alloys and composites regarding wear and corrosion behaviour. Optimisation of the anodising process depends on microstructural constituents contained in aluminium alloys and represents a key task, consisting of the control of process parameters and electrolyte formulation. We applied the micro-capillary technique known from corrosion studies and modified it to form anodic aluminium oxide films on high-strength aluminium alloys in comparison to pure aluminium in sulphuric acid. A glass capillary with an opening of 800âÎŒm in diameter was utilized. Corresponding electrochemical measurements during potentiodynamic and potentiostatic anodisation revealed anodic current responses similar to conventional anodisation. The measurement of film thickness was adapted to the thin anodised spots using ellipsometry and energy dispersive X-ray analysis. Cross sections prepared by focused ion beam milling confirm the thickness results and show the behaviour of intermetallic phases depending on the anodising potential. Consequently, micro-capillary anodising proved to be an effective tool for developing appropriate anodisation conditions for aluminium alloys and composites because it allows quick variation of electrolyte composition by applying low electrolyte volumes and rapid film formation due to short process durations at small areas and more flexible variation of process parameters due to the used set-up
Review on Pediatric Malignant Focal Liver Lesions with Imaging Evaluation: Part II
Malignant focal liver lesions (FLLs) represent various kinds of epithelial and mesenchymal
tumors. In pediatric patients, the understanding of pediatric liver diseases and associated imaging
manifestations is essential for making accurate diagnosis and differential diagnosis. This paper will
discuss the latest knowledge of the common pediatric malignant FLLs, including undifferentiated
embryonal sarcoma, rhabdomyosarcoma, epithelioid hemangioendothelioma, angiosarcoma, and
malignant rhabdoid tumor. Medical imaging features are not only helpful for clinical diagnosis, but
can also be useful in the evaluation and follow-up of pre- and post-treatment. The future perspectives
of contrast-enhanced ultrasound (CEUS) enhancement patterns of FLLs in pediatric patients are also
mentioned
Review on Pediatric Malignant Focal Liver Lesions with Imaging Evaluation: Part I
Malignant focal liver lesions (FLLs) are commonly reported in adults but rarely seen in the
pediatric population. Due to the rarity, the understanding of these diseases is still very limited. In
children, most malignant FLLs are congenital. It is very important to choose appropriate imaging
examination concerning various factors. This paper will outline common pediatric malignant FLLs,
including hepatoblastoma, hepatocellular carcinoma, and cholangiocarcinoma and discuss them
against the background of the latest knowledge on comparable/similar tumors in adults. Medical
imaging features are of vital importance for the non-invasive diagnosis and follow-up of treatment
of FLLs in pediatric patients. The use of CEUS in pediatric patients for characterizing those FLLs
that remain indeterminate on conventional B mode ultrasounds may be an effective option in the
future and has great potential to be integrated into imaging algorithms without the risk of exposure
to ionizing radiation
Recently photoassimilated carbon and fungus-delivered nitrogen are spatially correlated in the ectomycorrhizal tissue of Fagus sylvatica
Ectomycorrhizal plants trade plantâassimilated carbon for soil nutrients with their fungal partners. The underlying mechanisms, however, are not fully understood. Here we investigate the exchange of carbon for nitrogen in the ectomycorrhizal symbiosis of Fagus sylvatica across different spatial scales from the root system to the cellular level. We provided (15)Nâlabelled nitrogen to mycorrhizal hyphae associated with one half of the root system of young beech trees, while exposing plants to a (13)CO(2) atmosphere. We analysed the shortâterm distribution of (13)C and (15)N in the root system with isotopeâratio mass spectrometry, and at the cellular scale within a mycorrhizal root tip with nanoscale secondary ion mass spectrometry (NanoSIMS). At the root system scale, plants did not allocate more (13)C to root parts that received more (15)N. Nanoscale secondary ion mass spectrometry imaging, however, revealed a highly heterogenous, and spatially significantly correlated distribution of (13)C and (15)N at the cellular scale. Our results indicate that, on a coarse scale, plants do not allocate a larger proportion of photoassimilated C to root parts associated with Nâdelivering ectomycorrhizal fungi. Within the ectomycorrhizal tissue, however, recently plantâassimilated C and fungusâdelivered N were spatially strongly coupled. Here, NanoSIMS visualisation provides an initial insight into the regulation of ectomycorrhizal C and N exchange at the microscale
Therapy-refractory Panton Valentine Leukocidin-positive community-acquired methicillin-sensitive Staphylococcus aureus sepsis with progressive metastatic soft tissue infection: a case report
We report a case of fulminant multiple organ failure including the Acute Respiratory Distress Syndrome (ARDS), haemodynamic, and renal failure due to community-acquired methicillin-sensitive Panton Valentine Leukocidin (PVL) positive spa-type 284 (ST121) Staphylococcus aureus septic shock. The patient's first clinical symptom was necrotizing pneumonia. Despite organism-sensitive triple antibiotic therapy with linezolid, imipenem and clindamycin from the first day of treatment, progressive abscess formation in multiple skeletal muscles was observed. As a result, repeated surgical interventions became necessary. Due to progressive soft tissue infection, the anti-microbial therapy was changed to a combination of clindamycin and daptomycin. Continued surgical and antimicrobial therapy finally led to a stabilisation of the patients' condition. The clinical course of our patient underlines the existence of a "PVL-syndrome" which is independent of in vitro Staphylococcus aureus susceptibility. The PVL-syndrome should not only be considered in patients with soft tissue or bone infection, but also in patients with pneumonia. Such a condition, which may easily be mistaken for uncomplicated pneumonia, should be treated early, aggressively and over a long period of time in order to avoid relapsing infection
Formkonstanz und Bedeutungswandel. ArchÀologische Fallstudien und medienwissenschaftliche Reflexionen
Der vorliegende Band initiiert ein interdisziplinÀres GesprÀch zu der Frage, unter welchen Bedingungen sich
Formenrepertoires und Semantiken von statuarischen Darstellungen, Sarkophagen und anderen medialen Figurationen im Spannungsfeld von Persistenz und Wandel historisch tradieren. Dabei wird das Problem von Formkonstanz und Bedeutungswandel in Fallstudien aus der doppelten Perspektive der ArchĂ€ologie und der Medientheorie behandelt. Im gemeinsamen Fokus steht die Aussage von BildentwĂŒrfen und Figurentypen im Wandel von Zeit und Aufstellungskontexten, aber auch im Wechsel von Formaten und Medien. Wenngleich Figuren und Darstellungsschemata aus einem bestimmten Anlass, fĂŒr einen bestimmten Kontext und mit einer spezifischen Bedeutung geschaffen worden sind, konnten sie in einer sekundĂ€ren Verwendung neu kontextualisiert und dadurch mit neuen Bedeutungen aufgeladen werden. Gerade Ăbertragungen dieser Art, bei denen die ursprĂŒnglich intendierten inhaltlichen BezĂŒge sich verschoben oder sogar vollstĂ€ndig verloren gingen, sicherten vielfach die nachhaltige Rezeption morder Werke
Römische Götterbilder der mittleren und spÀten Kaiserzeit
Die Götterbilder der fortgeschrittenen römischen Kaiserzeit folgen einer traditionellen Bildsprache, die durch die vorbildhaften Statuen der griechischen Klassik geprĂ€gt ist. Gleichzeitig unterscheiden sie sich signifikant von frĂŒheren Epochen: Vorbilder werden variiert, Elemente verschiedener Bildwerke miteinander kombiniert und eigene Bild- und ErzĂ€hlzusammenhĂ€nge neu geschaffen. Die Götterstatuen des 2. bis 4. Jahrhunderts n. Chr. erhalten immer mehr Attribute und dekorative Details; StatuenstĂŒtzen und Plinthen werden mit beigeordneten Figuren bereichert; statuarische Gruppen setzen HandlungsablĂ€ufe in Szene.
Die BeitrÀge dieses Bandes untersuchen, wie Götterbilder der mittleren und der spÀteren Kaiserzeit gewandelte religiöse Vorstellungen visualisieren und ihnen eine sinnlich erfahrbare PrÀsenz verleihen. Sie zeigen, wie sich damit Àltere Auffassungen vom Wesen der Götter stabilisieren, gleichzeitig aber auch neue religiöse Auffassungen manifest und verstetigt werden
Changes in the CFC inventories and formation rates of upper Labrador Sea Water, 1997-2001
Chlorofluorocarbon (component CFC-11) and hydrographic data from 1997, 1999, and 2001 are presented to track the large-scale spreading of the Upper Labrador Sea Water (ULSW) in the subpolar gyre of the North Atlantic Ocean. ULSW is CFC rich and comparatively low in salinity. It is located on top of the denser âclassicalâ Labrador Sea Water (LSW), defined in the density range ÏÎ = 27.68â27.74 kg mâ3. It follows spreading pathways similar to LSW and has entered the eastern North Atlantic. Despite data gaps, the CFC-11 inventories of ULSW in the subpolar North Atlantic (40°â65°N) could be estimated within 11%. The inventory increased from 6.0 ± 0.6 million moles in 1997 to 8.1 ± 0.6 million moles in 1999 and to 9.5 ± 0.6 million moles in 2001. CFC-11 inventory estimates were used to determine ULSW formation rates for different periods. For 1970â97, the mean formation rate resulted in 3.2â3.3 Sv (Sv ⥠106 m3 sâ1). To obtain this estimate, 5.0 million moles of CFC-11 located in 1997 in the ULSW in the subtropical/tropical Atlantic were added to the inventory of the subpolar North Atlantic. An estimate of the mean combined ULSW/LSW formation rate for the same period gave 7.6â8.9 Sv. For the years 1998â99, the ULSW formation rate solely based on the subpolar North Atlantic CFC-11 inventories yielded 6.9â9.2 Sv. At this time, the lack of classical LSW formation was almost compensated for by the strongly pronounced ULSW formation. Indications are presented that the convection area needed in 1998â99 to form this amount of ULSW exceeded the available area in the Labrador Sea. The Irminger Sea might be considered as an additional region favoring ULSW formation. In 2000â01, ULSW formation weakened to 3.3â4.7 Sv. Time series of layer thickness based on historical data indicate that there exists considerable variability of ULSW and classical LSW formation on decadal scales
How to perform Contrast-Enhanced Ultrasound (CEUS)
"How to perform contrast-enhanced ultrasound (CEUS)" provides general advice on the use of ultrasound contrast agents (UCAs) for clinical decision-making and reviews technical parameters for optimal CEUS performance. CEUS techniques vary between centers, therefore, experts from EFSUMB, WFUMB and from the CEUS LI-RADS working group created a discussion forum to standardize the CEUS examination technique according to published evidence and best personal experience. The goal is to standardise the use and administration of UCAs to facilitate correct diagnoses and ultimately to improve the management and outcomes of patients
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