| 1. |
- Aspers, Patrik, et al.
(författare)
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Market Fashioning
- 2020
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Ingår i: Theory and society. - : Springer Science and Business Media LLC. - 0304-2421 .- 1573-7853. ; 49, s. 417-438
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Tidskriftsartikel (refereegranskat)abstract
- How do markets come about? This article offers a first systematic analysis of three different ideal types of market fashioning: mutual adjustment, organization, and fields. Although aspects of these are identifiable in most empirical markets, these three ideal types provide analytic tools for students of real markets and marketplaces. After going through this comprehensive literature, it is argued that mutual adjustment, which refers to non-planned processes, is affinity with markets in which products are differentiated, for example, producer markets. Organization refers to process driven by attempts to decide for others and shows affinity with markets for standardized and homogenous products, for example, stock exchanges. Organization also accounts for the making of marketplaces. The broader notion of fields does not refer to any specific process, but accounts for the context of market fashioning and its respective power struggles.
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| 2. |
- Aspers, Patrik, et al.
(författare)
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Wie entstehen Märkte? Ein Vergleich idealtypischer Erklärungsansätze in Ökonomie und Wirtschaftssoziologie : [How do markets emerge? A comparison of ideal-typical explanations in economics and economic sociology]
- 2022
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Ingår i: Berliner Journal für Soziologie. - : Springer Science and Business Media LLC. - 0863-1808 .- 1862-2593. ; 32:4, s. 533-562
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Tidskriftsartikel (refereegranskat)abstract
- In Theorien des Ökonomischen wird die Frage nach der Entstehung von Märkten vergleichsweise randständig behandelt. Wie der Artikel zeigt, lassen sich die dominanten Erklärungsmuster in drei Gruppen zusammenfassen, die jeweils einem idealtypischen Leitkonzept der Marktgestaltung folgen: wechselseitige Anpassung, Organisation und soziale Felder. Während Theorien der wechselseitigen Anpassung von der quasi-natürlichen Genese von Märkten im Prozess reziproker Anerkennungsprozesse der Marktteilnehmer ausgehen, fokussieren Organisationstheorien die bewusste Gestaltung relevanter Institutionen, insbesondere, aber nicht nur durch den Staat. Die durch Bourdieu und Fligstein inspirierte Theorie sozialer Felder nimmt die außerökonomische Einbettung von Marktentstehungsprozessen in den Blick, liefert jedoch keinen genuinen Beitrag zur Interpretation solcher Prozesse im engeren Sinne. Der eingehende analytische Vergleich der jeweiligen Literatur zeigt die Anwendbarkeit der jeweiligen Erklärungsmuster. So betrifft das Phänomen der wechselseitigen Anpassung vor allem ungeplante Prozesse und Märkte mit starker Produktdifferenzierung, das Phänomen der Organisation hingegen vor allem „gerahmte“ Märkte für standardisierte Produkte sowie Wertpapiermärkte. Theorien sozialer Felder adressieren übergreifend den sozialen Kontext und die Machtkämpfe, in denen Märkte als politisch-kulturelle Strukturen ausgehandelt werden. Auf Basis dieser Beobachtung plädiert der Beitrag für eine integrierende Perspektive, die die Vorteile der jeweiligen Ansätze ohne Reduktion auf ein Paradigma in sich vereint.
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| 3. |
- Bengtsson, Alexander, et al.
(författare)
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Comparison of contrast-to-noise ratios of different detection methods in ultrasound optical tomography
- 2022
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Ingår i: Biomedical Optics Express. - 2156-7085. ; 13:9, s. 4834-4850
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Tidskriftsartikel (refereegranskat)abstract
- Ultrasound optical tomography (UOT) is a hybrid imaging modality based on interaction between ultrasound and light, with a potential to extend optical imaging capabilities in biological tissues to depths of several centimeters. Several methods have been developed to detect the UOT signal. To better understand their potential for deep tissue imaging, we present a theoretical contrast-to-noise comparison between the spectral hole burning, single-shot off-axis holography, speckle contrast, and photorefractive detection methods for UOT. Our results indicate that spectral hole burning filters have the potential to reach the largest imaging depths. We find that digital off-axis holography and photorefractive detection can have good contrast-to-noise ratio at significant depths. The speckle contrast method has a smaller penetration depth comparatively.
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| 4. |
- Bengtsson, Alexander
(författare)
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Material and technique development for ultrasound optical tomography using spectral hole burning filters
- 2022
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The molecular sensitivity provided by optical photons has potential advantages in medical diagnostics, for example, in distinguishing healthy from cancerous tissue. However, scattering resulting from inhomogeneities in the refractive index of tissues prevents spatially resolved optical measurements in biological material, except at very shallow depths. This thesis presents research on a medical imaging technique called ultrasound optical tomography (UOT), which overcomes the limit on resolution resulting from scattering by combining photons and ultrasound. Photons are locally frequency shifted (tagged) by ultrasonic waves inside the tissue. Optical contrast can be obtained with ultrasonic spatial resolution by detecting these tagged photons. In this work, the tagged photons were detected using narrowband optical passband filters created in rare-earth-ion-doped crystals using spectral hole burning techniques. The thesis presents UOT measurements using Pr3+:Y2SiO5 filters operating at 606 nm, which characterize the signal strength under various well-controlled experimental conditions. Improved understanding of the performance of an optimized UOT set-up based on spectral hole burning was obtained by fitting experimental data with theoretical models, indicating that imaging depths of several centimetres should be possible in biological tissues. A theoretical comparison of the many UOT methods described in the literature is presented. The findings indicate that spectral hole burning filters may have better contrast-to-noise scaling, and thus potentially greater imaging depths, than other UOT methods such as digital off-axis holography, photorefractive holography, and speckle contrast imaging. A major challenge for spectral-hole-burning filter-based UOT to become useful for in vivo applications, is to identify and develop crystals capable of supporting the required high-contrast filters at wavelengths within the optical window for tissue (~650-950 nm). Experimental values of the filter contrast obtained in UOT measurements in this wavelength range have so far been limited to 14 dB. Based on spectroscopic measurements, Tm3+:LaF3 is proposed as a candidate for UOT filtering at 690 and 797 nm. Measurements show that a filter contrast above 50 dB is possible at the 690 nm transition for a collimated laser beam. The high filter contrast of Tm3+:LaF3 is expected to be important for the future development of UOT using spectral hole burning filters.
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| 5. |
- Bengtsson, Jenny, et al.
(författare)
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Chemical Recycling of a Textile Blend from Polyester and Viscose, Part II : Mechanism and Reactivity during Alkaline Hydrolysis of Textile Polyester
- 2022
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Ingår i: Sustainability. - : MDPI. - 2071-1050. ; 14:11
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Tidskriftsartikel (refereegranskat)abstract
- Chemical recycling of textiles holds the potential to yield materials of equal quality and value as products from virgin feedstock. Selective depolymerization of textile polyester (PET) from regenerated cellulose/PET blends, by means of alkaline hydrolysis, renders the monomers of PET while cellulose remains in fiber form. Here, we present the mechanism and reactivity of textile PET during alkaline hydrolysis. Part I of this article series focuses on the cellulose part and a possible industrialization of such a process. The kinetics and reaction mechanism for alkaline hydrolysis of polyester packaging materials or virgin bulk polyester are well described in the scientific literature; however, information on depolymerization of PET from textiles is sparse. We find that the reaction rate of hydrolysis is not affected by disintegrating the fabric to increase its surface area. We ascribe this to the yarn structure, where texturing and a low density assures a high accessibility even without disintegration. The reaction, similar to bulk polyester, is shown to be surface specific and proceeds via endwise peeling. Finally, we show that the reaction product terephthalic acid is pure and obtained in high yields. © 2022 by the authors.
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| 6. |
- Bondza, Saskia, et al.
(författare)
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A simple experimental method for measuring the thermal sensitivity of single-mode fibers
- 2020
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Ingår i: Review of Scientific Instruments. - : AIP Publishing. - 0034-6748 .- 1089-7623. ; 91:10
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Tidskriftsartikel (refereegranskat)abstract
- We present a simple technique to experimentally determine the optical-path length change with temperature for optical single-mode fibers. Standard single-mode fibers act as natural low-finesse cavities, with the Fresnel reflection of the straight cleaved surfaces being ∼3%, for the laser light coupled to them. By measuring the intensity variations due to interference of light reflected from the fiber front and end surfaces, while ramping the ambient temperature, the thermal sensitivity of the optical-path length of the fiber can be derived. Light was generated by a narrow linewidth, low drift laser. With our fairly short test fibers, we found that it was possible to reach a relative precision of the temperature sensitivity, compared to a reference fiber, on the 0.4%-2% scale and an absolute precision of 2%-5%, with the potential to improve both by an order of magnitude. The results for single-acrylate, dual-acrylate, and copper- and aluminum-coated fibers are presented. Values are compared with analytic models and results from a finite element method simulation. With the aid of these measurements, a simple fiber-interferometer, which is insensitive to thermal drifts, could be constructed.
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| 7. |
- Haglund, Åsa, 1976, et al.
(författare)
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Are blue and ultraviolet VCSELs a reality or just a dream?
- 2020
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Blue-emitting vertical-cavity surface-emitting lasers (VCSELs) with high optical output powers and decent threshold current densities have recently been demonstrated, but the power efficiency is still below 10%. We will give an overview of the challenges to realize high-performing devices and summarize state-of-the-art results, including our schemes for optically guided devices that are used in the best blue VCSELs today. In addition, we will present our method to simultaneously achieve high-reflectivity mirrors and good control over the cavity length for ultraviolet VCSELs. This has resulted in, to the best of our knowledge, the shortest VCSEL emission wavelength around 310 nm.
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| 8. |
- Haglund, Åsa, 1976, et al.
(författare)
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Recent progress for blue VCSELs and challenges to move to UV
- 2020
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- We will summarize state-of-the-art results in III-nitride-based vertical-cavity surface-emitting lasers (VCSELs) and the main challenges in going from blue to ultraviolet-emitting devices. In particular we will highlight how to reduce threshold current densities by using optically guided cavities and our method to simultaneously achieve high-reflectivity mirrors and good control over the cavity length for AlGaN-based ultraviolet VCSELs. The latter has resulted in the shortest emission wavelength from a VCSEL at around 310 nm. This claim of lasing is supported by a nonlinear increase in output power versus pump power and a simultaneous beam width and spectral narrowing around threshold.
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| 9. |
- Hedlund, Malin, et al.
(författare)
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Type I IFN system activation in newborns exposed to Ro/SSA and La/SSB autoantibodies in utero
- 2020
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Ingår i: RMD Open. - : BMJ. - 2056-5933. ; 6:1
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: In utero exposure of the fetus to Ro/La autoantibodies may lead to congenital heart block (CHB). In the mother, these autoantibodies are associated with activation of the type I interferon (IFN)-system. As maternal autoantibodies are transferred to the fetus during pregnancy, we investigated whether the type I IFN-system is activated also in newborns of anti-Ro/La positive mothers, and whether fetal IFN activation is affected by maternal immunomodulatory treatment.METHODS: Blood drawn at birth from anti-Ro/La positive mothers, their newborns and healthy control pairs was separated into plasma and peripheral blood mononuclear cells (PBMC). PBMC were analysed directly or cultured. mRNA expression was analysed by microarrays, cell surface markers by flow cytometry, and IFNα levels by immunoassays.RESULTS: We observed increased expression of IFN-regulated genes and elevated plasma IFNα levels not only in anti-Ro/La positive women, but also in their newborns. CD14+ monocytes of both anti-Ro/La positive mothers and their neonates showed increased expression of Sialic acid-binding Ig-like lectin-1, indicating cellular activation. Notably, the IFN score of neonates born to mothers receiving immunomodulatory treatment was similar to that of controls, despite persistent IFN activation in the mothers. In both maternal and neonatal PBMC, IFNα production was induced when cells were cultured with anti-Ro/La positive plasma.CONCLUSIONS: Ro/La autoantibody-exposed neonates at risk of CHB have signs of an activated immune system with an IFN signature. This study further demonstrates that neonatal cells can produce IFNα when exposed to autoantibody-containing plasma, and that maternal immunomodulatory treatment may diminish the expression of IFN-regulated genes in the fetus.
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| 10. |
- Hill, David, et al.
(författare)
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Acousto-optic interaction strengths in optically scattering media using high pressure acoustic pulses
- 2021
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Ingår i: Biomedical Optics Express. - 2156-7085. ; 12:6, s. 3196-3213
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Tidskriftsartikel (refereegranskat)abstract
- Ultrasound optical tomography (UOT) is a developing medical imaging technique with the potential to noninvasively image tissue oxygenation at depths of several centimeters in human tissue. To accurately model the UOT imaging, it is necessary the calculate the signal produced by the interaction between ultrasound and light in the scattering medium. In this paper we present a rigorous description for modeling this process for ultrasound pulses in the non-linear regime with peak pressures ranging up to the medical safety limit. Simulation results based on the presented model agree well with measurements performed with fully characterized ultrasound pulses. Our results also indicate that the UOT modeling process can be accurately simplified by disregarding the acoustically induced movement of scatterers. Our results suggest that the explored model and its software implementation can be used as a virtual lab to aid future development of pulses and UOT imaging algorithms.
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