TY  - JOUR
A1  - Staab, Torsten E. M.
A1  - Lotter, Frank
A1  - Mühle, Uwe
A1  - Elsayed, Mohamed
A1  - Petschke, Danny
A1  - Schubert, Thomas
A1  - Ibrahim, Alaa M.
A1  - Krause-Rehberg, Reinhard
A1  - Kieback, Bernd
T1  - The decomposition process in high-purity Al-1.7 at.% Cu alloys with trace elements: preservation of quenched-in vacancies by In, Sn and Pb influencing the ​θ′formation
JF  - Journal of Materials Science
N2  - Aluminium-copper alloys of the 2xxx type receive their excellent mechanical properties by the formation of copper-rich precipitates during hardening. Size, distribution and crystal structure of the formed precipitates determine the final strength of those alloys. Adding traces of certain elements, which bind to vacancies, significantly influences the decomposition behaviour, i.e. the diffusion of the copper atoms. For high-purity ternary alloys (Al-1.7 at.% Cu-X), we investigate the interaction of copper and trace element atoms (X=In, Sn, and Pb) with quenched-in vacancies by Positron Annihilation Lifetime Spectroscopy (PALS). By employing Vickers microhardness, Differential Scanning Calorimetry (DSC) and Small Angle X-Ray Scattering (SAXS) we obtain a comprehensive picture of the decomposition process: opposite to predicted binding energies to vacancies by ab-initio calculations we find during ageing at room and elevated temperature a more retarded clustering of copper in the presence of In rather than for Sn additions, while Pb, having the highest predicted binding to vacancies, shows nearly no retarding effect compared to pure Al-Cu. If the latter would be due to a limited solubility of lead, it had to be below 2 ppm. Transmission Electron Microscopy (TEM) as imaging method complements our findings. Annealing the quenched Al-1.7 at.% Cu-X-alloys containing 100 ppm In or Sn at 150∘C leads to finely distributed θ′-precipitates on the nanoscale, since due to the trace additions the formation temperature of θ′ is lowered by more than 100∘C. According to TEM small agglomerates of trace elements (In, Sn) may support the early nucleation for the θ′-precipitates.
KW  - Aluminium-copper
KW  - alloys
KW  - trace elements
Y1  - 2021
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-269103
SN  - 1573-4803
VL  - 56
IS  - 14
ER  - 
TY  - JOUR
A1  - Dresen, Ellen
A1  - Pimiento, Jose M.
A1  - Patel, Jayshil J.
A1  - Heyland, Daren K.
A1  - Rice, Todd W.
A1  - Stoppe, Christian
T1  - Overview of oxidative stress and the role of micronutrients in critical illness
JF  - Journal of Parenteral and Enteral Nutrition
N2  - Inflammation and oxidative stress represent physiological response mechanisms to different types of stimuli and injury during critical illness. Its proper regulation is fundamental to cellular and organismal survival and are paramount to outcomes and recovery from critical illness. A proper maintenance of the delicate balance between inflammation, oxidative stress, and immune response is crucial for resolution from critical illness with important implications for patient outcome. The extent of inflammation and oxidative stress under normal conditions is limited by the antioxidant defense system of the human body, whereas the antioxidant capacity is commonly significantly compromised, and serum levels of micronutrients and vitamins significantly depleted in patients who are critically ill. Hence, the provision of antioxidants and anti-inflammatory nutrients may help to reduce the extent of oxidative stress and therefore improve clinical outcomes in patients who are critically ill. As existing evidence of the beneficial effects of antioxidant supplementation in patients who are critically ill is still unclear, actual findings about the most promising anti-inflammatory and antioxidative candidates selenium, vitamin C, zinc, and vitamin D will be discussed in this narrative review. The existing evidence provided so far demonstrates that several factors need to be considered to determine the efficacy of an antioxidant supplementation strategy in patients who are critically ill and indicates the need for adequately designed multicenter prospective randomized control trials to evaluate the clinical significance of different types and doses of micronutrients and vitamins in selected groups of patients with different types of critical illness.
KW  - critical illness
KW  - vitamins
KW  - vitamin C
KW  - inflammation
KW  - medical nutrition therapy
KW  - oxidative stress
KW  - selenium
KW  - trace elements
KW  - micronutrients
KW  - vitamin D
KW  - zinc
Y1  - 2023
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-318186
VL  - 47
SP  - S38
EP  - S49
ER  -