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- Nordborg, Jenni, 1970
(författare)
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Non-Linear Optical Titanyl Arsenates Crystal Growth and Properties
- 2000
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Crystals are appreciated not only for their appearance, but also for their unique physical properties which are utilized by the photonic industry in appliances that we come across every day. An important part of enabling the technical use of optical devices is the manufacture of crystals. This dissertation deals with a specific group of materials called the potassium titanyl phosphate (KTP) family, known for their non-linear optical and ferroelectric properties. The isomorphs vary in their linear optical and dielectric properties, which can be tuned to optimize device performance by forming solid solutions of the different materials. Titanyl arsenates have a wide range of near-infrared transmission which makes them useful for tunable infrared lasers. The isomorphs examined in the present work were primarily RbTiOAsO4 (RTA) and CsTiOAsO4 (CTA) together with the mixtures RbxCs1-xTiOAsO4 (RCTA). Large-scale crystals were grown by top seeding solution growth utilizing a three-zone furnace with excellent temperature control. Sufficiently slow cooling and constant upward lifting produced crystals with large volumes useable for technical applications. Optical quality RTA crystals up to 10 ´ 12 ´ 20 mm were grown. The greater difficulty in obtaining good crystals of CTA led to the use of mixed RCTA materials. The mixing of rubidium and cesium in RCTA is more favorable to crystal growth than the single components in pure RTA and CTA. Mixed crystals are rubidium-enriched and contain only 20 - 30 % of the cesium concentration in the flux. The cesium atoms show a preference for the larger cation site. The network structure is very little affected by the cation substitution; consequently, the non-linear optical properties of the Rb-rich isomorphic mixtures of RTA and CTA can be expected to remain intact. Crystallographic methods utilizing conventional X-ray tubes, synchrotron radiation and neutron diffraction have been employed to investigate the properties of the atomic structures. It was shown that, instead of two cation sites, there is a considerable distribution of the cations over additional sites related by pseudosymmetry. The cation disorder is temperature dependent and seems to be universal for the KTP family. Charge density maps for RTA reflect the anisotropy of non-linear susceptibility, which is greater in the directions with strong locally anti-symmetric components of the residual electron density. Accordingly, the Ti-O and As-O covalent bonds can be related to the linear and non-linear susceptibility of these materials.
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| 3. |
- Stenzinger, Albrecht, et al.
(författare)
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Implementation of precision medicine in healthcare—A European perspective
- 2023
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Ingår i: Journal of Internal Medicine. - 0954-6820 .- 1365-2796. ; 294:4, s. 437-454
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Forskningsöversikt (refereegranskat)abstract
- The technical development of high-throughput sequencing technologies and the parallel development of targeted therapies in the last decade have enabled a transition from traditional medicine to personalized treatment and care. In this way, by using comprehensive genomic testing, more effective treatments with fewer side effects are provided to each patient—that is, precision or personalized medicine (PM). In several European countries—such as in England, France, Denmark, and Spain—the governments have adopted national strategies and taken “top-down” decisions to invest in national infrastructure for PM. In other countries—such as Sweden, Germany, and Italy with regionally organized healthcare systems—the profession has instead taken “bottom-up” initiatives to build competence networks and infrastructure to enable equal access to PM. In this review, we summarize key learnings at the European level on the implementation process to establish sustainable governance and organization for PM at the regional, national, and EU/international levels. We also discuss critical ethical and legal aspects of implementing PM, and the importance of access to real-world data and performing clinical trials for evidence generation, as well as the need for improved reimbursement models, increased cross-disciplinary education and patient involvement. In summary, PM represents a paradigm shift, and modernization of healthcare and all relevant stakeholders—that is, healthcare, academia, policymakers, industry, and patients—must be involved in this system transformation to create a sustainable, non-siloed ecosystem for precision healthcare that benefits our patients and society at large.
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