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In this work, a Ti–29Nb–13Ta–4.6Zr–xO Gum Metal with two significantly different oxygen levels (388 and 3570 ppm) was investigated during deformation. The alloys were compressed during in situ high-energy X-ray diffraction using three different strain rates, 10−4, 10−3, and 10−1 s−1, in order to evaluate their influence on phase stability and mechanical properties. The influence of oxygen on the deformation process was also studied. Deformation takes place by twinning, stress-induced, and reverse martensitic transformation and was observed, for some samples, a spinodal decomposition of the β-phase during elastic deformation. The mechanical properties were similar for the different rates employed when considering the same oxygen level. The alloy with a higher amount of oxygen, however, showed a substantial increase in mechanical strength, with a yield strength of around 680 MPa, which is more than three times higher than for the specimen with 388 ppm of oxygen.
Postoperative cognitive impairment is among the most common medical complications associated with surgical interventions – particularly in elderly patients. In our aging society, it is an urgent medical need to determine preoperative individual risk prediction to allow more accurate cost–benefit decisions prior to elective surgeries. So far, risk prediction is mainly based on clinical parameters. However, these parameters only give a rough estimate of the individual risk. At present, there are no molecular or neuroimaging biomarkers available to improve risk prediction and little is known about the etiology and pathophysiology of this clinical condition. In this short review, we summarize the current state of knowledge and briefly present the recently started BioCog project (Biomarker Development for Postoperative Cognitive Impairment in the Elderly), which is funded by the European Union. It is the goal of this research and development (R&D) project, which involves academic and industry partners throughout Europe, to deliver a multivariate algorithm based on clinical assessments as well as molecular and neuroimaging biomarkers to overcome the currently unsatisfying situation.
Recent studies suggest that the use of vegetable oils at expense of fish oil in aquaculture feeds might have potential negative effects on fish redox homeostasis and adiposity. Resveratrol (RESV) is a lipid-soluble phytoalexin present in fruits and vegetables with proven in vivo antioxidant function in animals. The present study aims to assess the potential use of RESV in Atlantic salmon feeds. To this end, post-smolt salmons with an initial BW of 148±3 g were fed four experimental diets for 15 weeks. A diet low in fish oil served as a control and was supplemented with 0, 0.5, 1.5 and 2.5 g/kg of RESV, respectively. The effect of the experimental diets on animal performance, tissue fatty acid composition, and the expression of genes encoding proteins involved in antioxidant signalling, lipid peroxidation, and metabolism were studied. Resveratrol significantly reduced feed intake and final BW of the salmon. Feeding RESV did not affect the sum of saturated and monounsaturated fatty acids or total lipids in the fillet. While the content of total polyunsaturated fatty acids was not affected, the percentages of some fatty acids in the liver and fillet were changed by RESV. Furthermore, in liver, the relative expression of glutathione peroxidase 4b, nuclear factor-like 2, and arachidonate 5-lipoxygenase remained unchanged across treatment groups. In conclusion, the negative impact of dietary RESV on FI and hence reduction of the BW discourages its inclusion in low fish oil diets for Atlantic salmon.
The mainstay of management of epistaxis refractory to first aid and cautery is intranasal packing. This review aimed to identify evidence surrounding nasal pack use.
A systematic review of the literature was performed using standardised methodology.
Twenty-seven eligible articles were identified relating to non-dissolvable packs and nine to dissolvable packs. Nasal packing appears to be more effective when applied by trained professionals. For non-dissolvable packs, the re-bleed rates for Rapid Rhino and Merocel were similar, but were higher with bismuth iodoform paraffin paste packing. Rapid Rhino packs were the most tolerated non-dissolvable packs. Evidence indicates that 96 per cent of re-bleeding occurs within the first 4 hours after nasal pack removal. Limited evidence suggests that dissolvable packs are effective and well tolerated by patients. There was a lack of evidence relating to: the duration of pack use, the economic effects of pack choice and the appropriate care setting for non-dissolvable packs.
Rapid Rhino packs are the best tolerated, with efficacy equivalent to nasal tampons. FloSeal is easy to use, causes less discomfort and may be superior to Merocel in anterior epistaxis cases. There is no strong evidence to support prophylactic antibiotic use.
The initial assessment of epistaxis patients commonly includes: first aid measures, observations, focused history taking, and clinical examinations and investigations. This systematic review aimed to identify evidence that informs how the initial assessment of these patients should be conducted.
A systematic review of the literature was performed using a standardised methodology and search strategy.
Seventeen articles were included. Factors identified were: co-morbidity, intrinsic patient factors, coagulation screening and ice pack use. Hypertension and anticoagulant use were demonstrated to adversely affect outcomes. Coagulation screening is useful in patients on anticoagulant medication. Four studies could not be accessed. Retrospective methodology and insufficient statistical analysis limit several studies.
Sustained ambulatory hypertension, anticoagulant therapy and posterior bleeding may be associated with recurrent epistaxis, and should be recorded. Oral ice pack use may decrease severity and can be considered as first aid. Coagulation studies are appropriate for patients with a history of anticoagulant use or bleeding diatheses.
There is variation regarding the use of surgery and interventional radiological techniques in the management of epistaxis. This review evaluates the effectiveness of surgical artery ligation compared to direct treatments (nasal packing, cautery), and that of embolisation compared to direct treatments and surgery.
A systematic review of the literature was performed using a standardised published methodology and custom database search strategy.
Thirty-seven studies were identified relating to surgery, and 34 articles relating to interventional radiology. For patients with refractory epistaxis, endoscopic sphenopalatine artery ligation had the most favourable adverse effect profile and success rate compared to other forms of surgical artery ligation. Endoscopic sphenopalatine artery ligation and embolisation had similar success rates (73–100 per cent and 75–92 per cent, respectively), although embolisation was associated with more serious adverse effects (risk of stroke, 1.1–1.5 per cent). No articles directly compared the two techniques.
Trials comparing endoscopic sphenopalatine artery ligation to embolisation are required to better evaluate the clinical and economic effects of intervention in epistaxis.
The reliability of InAlGaN multiple quantum well LEDs emitting around 308 nm has been investigated. The UV-B LEDs were stressed at constant current and current density, while the heat sink temperature was varied between 15°C and 80°C. The results reveal two different modes of the decrease of the optical power during aging. First, a fast reduction of the optical power within the first 100 h (mode 1) can be observed, followed by a slower degradation for operation times >100 h (mode 2). Mode 1 can be described as an initial degradation activation process which saturates after a certain time, whereas the second degradation mode can be described by a square-root time dependence of the optical power, suggesting a diffusion process to be involved. Both degradation modes are accompanied by changes of the I-V characteristic, particularly the reverse-bias leakage current and the drive voltage. Furthermore, the degradation behavior is strongly influenced by the temperature. Both, the maximum reduction of the optical power and the increase of the leakage current become stronger at higher temperatures.
In this contribution, we present an effective strategy for assembling and integrating functional, in situ formed micro- and nanosized structures. Microfluidic platforms are employed to form anisotropic hybrid structures and coordination polymers at the interface of two precursor streams. Microstamps, embedded in the microfluidic device and actuated by pressure, provide a facile and reliable technology for structure trapping, localization and integration.
The melt spinning technique (MST) combined with post annealing processes is evaluated for the development of thermoelectric nanocomposites. The evaluated ones are based on two components almost immiscible in solid state but with crystallographic correlation. One is taken from the V-VI-components system and the other one from the IV-VI-components system. This concept was applied to p-(Bi0,2Sb0,8)2Te3 and to p-[(Bi0,2Sb0,8)2Te3]1-xPbTex composites. MST samples of all types were characterised for some structural and thermoelectric properties. All V-VI materials are clearly textured after MST and show no deterioration concerning the thermoelectric properties even after subsequent annealing processes. Structural analysis of p-[(Bi0,2Sb0,8)2Te3]1-xPbTex composites gave significant hints for oriented precipitates of a IV-VI-rich phase incorporated into the V-VI-rich matrix. The thermoelectric figure of merit of the evaluated composites could be enhanced by suitable annealing procedures of both the quenched bulk materials and the melt spin material.
In this communication we illustrate the main steps required for the preprocessing of the Lyot Project Coronagraph data, starting from the raw data to the reduced data.
We then discuss the estimation of the performance on direct, unocculted data, by measuring the Strehl Ratio on these images. We show that Strehl Ratios of the order of 80% can be obtained for the best images in the H Band, using the AEOS telescope adaptive optics, and the Kermit infrared camera.
We then present a few methods to estimate the dynamic range in coronagraphic images, and their results are discussed.
In previous work, we described a protocol for measuring biofilm formation on opaque and non-opaque surfaces using reflected light. In the present work, we used the reflectance assay to assess biofilm formation for 14 strains of Enterococcus and compared our results with those obtained using a Crystal Violet (CV) assay. In general, the results for the two assays were in agreement: both identified the same Enterococcus strain as the highest biofilm-forming strain and the same two strains as the lowest biofilm-forming strains. However, two Enterococcus strains identified as high biofilm formers by the CV assay were not identified as such by the reflectance assay. A single numerical value was obtained for each of the reflectance assay results that corresponded well with the confluence of a biofilm (and presumably its depth) using phase contrast microscopy.
One of the major issues of joint implants is their loss (detachment) and subsequent failure after a limited number of years in application. Understanding and improving cell adhesion to implanting materials to extend lifespan, lubrication, and self-regeneration properties are therefore substantially important. In this research, we investigate effects of surface properties, such as wettabilty and texture on cell culture for the purpose of biotribological applications. Materials used are polyurethane, polyvinyl alcohol, and glass. Surface analysis indicates that surface structures have profound impact on cells growth.
A simple and natural explanation for the dynamics and morphology of the Local Group Dwarf Spheroidal galaxies, Draco (Dra) and Ursa Minor (UMi), is that they are weakly unbound stellar systems with no significant dark matter component. A gentle, but persistent, Milky Way (MW) tide has left them in their current kinematic and morphological state (the “parametric tidal excitation”). A new test of a dark matter dominated dS potential follows from a careful observation of the “clumpiness” of the dS stellar surface density.
Recently developed Zr-based metallic glass composites containing a ductile phase demonstrate improved mechanical properties such as high strength combined with good ductility compared to the glass monoliths. Zr-Nb-Cu-Ni-Al amorphous powders with bcc phase precipitates were obtained by high pressure gas atomization. Formation of the bcc phase in the amorphous matrix strongly depends on the material composition and cooling rates during solidification. Melt spinning using various wheel speeds selected to simulate the cooling rates during gas atomization was used to define a specific composition for gas atomization. Gas atomized powders were consolidated by warm extrusion. Various processing conditions including starting powder particle size, extrusion temperature and extrusion ratio were examined to obtain materials having various microstructural features. Structure and thermal stability of consolidated bulk metallic glass composites as well as selected mechanical properties will be discussed.
The effect of Al on the crystallization behavior of (Zr0.616Ti0.087 Nb0.027Cu0.15Ni0.12)100−xAlx melt-spun glassy ribbons with x = 7.5, 5, 2.5 and 0 was investigated by differential scanning calorimetry, x-ray diffraction and transmission electron microscopy. The devitrification of the ribbons is characterized by the formation of a metastable quasicrystalline phase during the first stage of the crystallization process even for the alloy with x = 0. Therefore, Al is not essential for quasicrystal formation in the present alloys. However, it affects the properties of the amorphous as well as of the quasicrystalline phase. With decreasing Al content, the temperature range of stability of the quasicrystalline phase increases whereas the thermal stability of the amorphous phase decreases together with a slight decrease of the extension of the supercooled liquid region. Thus, it is concluded that although the addition of Al improves the stability of the glassy phase, it has no beneficial effect on the formation of quasicrystals.
Medium-range order and quasicrystal formation in Zr57Cu20Al10Ni8Ti5 and Zr59Cu20Al10Ni8Ti3 metallic glasses are investigated by means of nuclear magnetic resonance (NMR). The samples are prepared by rapid solidification and annealed to induce primary quasicrystal formation. 27Al and 63Cu NMR spectra and spin relaxation curves are recorded before and after the annealing process. The spectral width of 27Al and 63Cu NMR spectra is relatively small and can be taken as a proof for the presence of medium-range order in these metallic glasses. By simulations of 27Al and 63Cu NMR second moments in various binary Al and Cu compounds the medium-range orders L12 AlZr3 and C11b CuZr2 can be identified in both as-quenched metallic glasses. After heat treatment both metallic glasses show considerable changes in the 63Cu NMR second moments, whereas the 27Al NMR second moments show only relatively small changes. Furthermore, the 63Cu NMR second moment after heat treatment in Zr57Cu20Al10Ni8Ti5 is about half as large as in Zr59Cu20Al10Ni8Ti3 indicating different types of crystallization during heat treatment.
General arguments for optimized coronagraphy in the search for planets are presented. First, off-axis telescopes provide the best telescopic platforms for use with coronagraphy, and telescope fabrication technology now allows the fabrication of such telescopes with diameters of up to 6.5 m. We show that in certain circumstances a smaller telescope with an off-axis primary has a signal-to-noise advantage compared with larger Cassegrain telescopes. Second, to fully exploit the advantages of the coronagraph for suppressing stray light, it is necessary to use a high Strehl ratio adaptive optics system. This can be best achieved initially with modest aperture telescopes of 3–4 m in diameter. Third, application of simultaneous differential imaging and simultaneous polarimetric techniques are required to reach the photon-limit of coronagraphic imaging. These three developments, if pursued together, will yield significant improvements in the search for planets.
We report on the microstructure, the thermal stability and the mechanical properties of slowly cooled Zr-Nb-Cu-Ni-Al alloys with ductile bcc phase precipitates embedded in a glassy or nanocrystalline matrix. The samples were prepared in form of rods by injection casting into a copper mold. The phase formation and the microstructure of the composite material were investigated by X-ray diffraction, EDX analysis and scanning and transmission electron microscopy. The thermal stability was examined by differential scanning calorimetry and the mechanical behavior was investigated by compression tests under quasistatic loading at room temperature. The formation of bcc phase dendrites and a glassy or nanocrystalline matrix is strongly governed by the alloy composition and the actual cooling rate during solidification. Besides, changes in composition and cooling rate lead to different volume fraction and size of the bcc phase precipitates and, hence, to different values of yield strength, elastic and plastic strain. The samples with nanocrystalline matrix show a homogeneous distribution of the bcc phase precipitates over the whole cross-section and exhibit higher yield strength and plastic strain than the samples containing an amorphous matrix. Illustrated by the presented results we show the possibility of obtaining tailored mechanical properties by control of composition and solidification conditions.