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| 2. |
- Filho, Luimar, et al.
(författare)
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The effect of N, C, Cr, and Nb content on silicon nitride coatings for joint applications
- 2020
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Ingår i: Materials. - : MDPI AG. - 1996-1944. ; 13:8
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Tidskriftsartikel (refereegranskat)abstract
- Ceramic coatings are an alternative to achieve or maintain a high wear resistance of metallic surfaces, and simultaneously allow for a reduction in metal ion release. Silicon nitride based (SiNx) coatings deposited by high power impulse magnetron sputtering (HiPIMS) have shown potential for use in joint implants seen from an improved chemical stability in combination with a good adhesion. The aim of this study was to investigate the effect of N, C, Cr and Nb content on the tribocorrosive performance of 3.7 to 8.8 µm thick SiNx coatings deposited by HiPIMS onto CoCrMo discs to improve the mechanical properties and/or chemical stability of SiNx .Coating composition was evaluated by X-ray photoelectron spectroscopy (XPS) and the surface roughness by Vertical Scanning Interferometry (VSI). Hardness and Young’s modulus were investigated by nanoindentation and coating adhesion was measured by scratch tests. Multidirectional wear tests against UHMWPE pins were performed for 2 million cycles in bovine serum solution (25%) at 37°C, at an estimated contact pressure of 2.1 MPa.Coatings with a relatively low hardness tended to fail earlier in the wear test, due to chemical reactions and eventually dissolution, accelerated by the tribological contact. In fact, while no definite correlation could be observed between coating composition (N: 42.6-55.5 at%, C: 0-25.7 at%, Cr: 0 or 12.8 at%, and Nb: 0-24.5 at%) and wear performance, it was apparent that high-purity and/or -density coatings (i.e. low oxygen content and high nitrogen content) were desirable to prevent coating and/or counter surface wear. Coatings deposited with a higher energy fulfilled the target profile in terms of low surface roughness (Ra<20nm), adequate adhesion (Lc2>30N), chemical stability over time in the tribocorrosive environment, as well as low polymer wear, presenting potential for a future application in joint bearings.
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| 4. |
- Kaufman, Darrell, et al.
(författare)
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A global database of Holocene paleotemperature records
- 2020
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Ingår i: Scientific Data. - : Springer Science and Business Media LLC. - 2052-4463. ; 7:1
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Tidskriftsartikel (refereegranskat)abstract
- A comprehensive database of paleoclimate records is needed to place recent warming into the longer-term context of natural climate variability. We present a global compilation of quality-controlled, published, temperature-sensitive proxy records extending back 12,000 years through the Holocene. Data were compiled from 679 sites where time series cover at least 4000 years, are resolved at sub-millennial scale (median spacing of 400 years or finer) and have at least one age control point every 3000 years, with cut-off values slackened in data-sparse regions. The data derive from lake sediment (51%), marine sediment (31%), peat (11%), glacier ice (3%), and other natural archives. The database contains 1319 records, including 157 from the Southern Hemisphere. The multi-proxy database comprises paleotemperature time series based on ecological assemblages, as well as biophysical and geochemical indicators that reflect mean annual or seasonal temperatures, as encoded in the database. This database can be used to reconstruct the spatiotemporal evolution of Holocene temperature at global to regional scales, and is publicly available in Linked Paleo Data (LiPD) format.
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| 5. |
- Schmidt, Susann, et al.
(författare)
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SiNx Coatings Deposited by Reactive High Power Impulse Magnetron Sputtering: Process Parameters Influencing the Nitrogen Content
- 2016
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Ingår i: ACS Applied Materials and Interfaces. - : AMER CHEMICAL SOC. - 1944-8244 .- 1944-8252. ; 8:31, s. 20386-20396
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Tidskriftsartikel (refereegranskat)abstract
- Reactive high power impulse magnetron sputtering (rHi-PIMS) was used to deposit silicon nitride (SiNx) coatings for biomedical applications. The SiNx growth and plasma characterization were conducted in an industrial coater, using Si targets and N-2 as reactive gas. The effects of different N-2-to-Ar flow ratios between 0 and 0.3, pulse frequencies, target power settings, and substrate temperatures on the discharge and the N content of SiNx coatings were investigated. Plasma ion mass spectrometry shows high amounts of ionized isotopes during the initial part of the pulse for discharges with low N-2-to-Ar flow ratios of amp;lt;0.16, while signals from ionized molecules rise with the N-2-to-Ar flow ratio at the pulse end and during pulse off times. Langmuir probe measurements show electron temperatures of 2-3 eV for nonreactive discharges and 5.0-6.6 eV for discharges in transition mode. The SiNx coatings were characterized with respect to their composition, chemical bond structure, density, and mechanical properties by X-ray photoelectron spectroscopy, X-ray reflectivity, X-ray diffraction, and nanoindentation, respectively. The SiNx deposition processes and coating properties are mainly influenced by the Nz-to-Ar flow ratio and thus by the N content in the SiNx films and to a lower extent by the HiPIMS frequencies and power settings as well as substrate temperatures. Increasing N2-to-Ar flow ratios lead to decreasing growth rates, while the N content, coating densities, residual stresses, and the hardness increase. These experimental findings were corroborated by density functional theory calculations of precursor species present during rHiPIMS.
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| 6. |
- Schwerzmann, Markus, et al.
(författare)
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Recommendations for advance care planning in adults with congenital heart disease: a position paper from the ESC Working Group of Adult Congenital Heart Disease, the Association of Cardiovascular Nursing and Allied Professions (ACNAP), the European Association for Palliative Care (EAPC), and the International Society for Adult Congenital Heart Disease (ISACHD).
- 2020
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Ingår i: European heart journal. - : Oxford University Press (OUP). - 1522-9645 .- 0195-668X. ; 41:43, s. 4200-4210
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Tidskriftsartikel (refereegranskat)abstract
- Survival prospects in adults with congenital heart disease (CHD), although improved in recent decades, still remain below expectations for the general population. Patients and their loved ones benefit from preparation for both unexpected and predictable deaths, sometimes preceded by a prolonged period of declining health. Hence, advance care planning (ACP) is an integral part of comprehensive care for adults with CHD. This position paper summarizes evidence regarding benefits of and patients' preferences for ACP and provides practical advice regarding the implementation of ACP processes within clinical adult CHD practice. We suggest that ACP be delivered as a structured process across different stages, with content dependent upon the anticipated disease progression. We acknowledge potential barriers to initiate ACP discussions and emphasize the importance of a sensitive and situation-specific communication style. Conclusions presented in this article reflect agreed expert opinions and include both patient and provider perspectives.
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