| 1. |
- Akselsson, Roland, et al.
(författare)
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Luftföroreningar vid svetsning
- 1977
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- PIXE-analyser kan utföras med utvecklad analysuppställning med noggrannhet och precision av c:a 10 % och med hög analyskapacitet. Ett dataprogram för evaluering av räntgenspektra presenteras. Inverkan av provtjocklek vid PIXE-analys av inhomogena prov har studerats och korrektioner föreslås. Fluorinnehållet i filterprov har bestämts, samtidigt med PIXE-analys, genom utnyttjande av en kärnfysikalisk reaktion som ger resultat med god noggrannhet och precision. Svetsaerosoler har karakteriserats m.h.a. PIXE, ESCA och TEM/EDAX. En uppställning för insamling av svetsaerosoler under utveckling och hittillsvarande resultat indikerar representativ provinsamling med god reproducerbarhet.
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| 2. |
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| 3. |
- Bergkvist, Max, 1976-
(författare)
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Studies on Polarised Light Spectroscopy
- 2019
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis project focuses on measurements of dermal microcirculation during vascular provocations with polarised light spectroscopy. This is done with a non-invasive method commercially available as Tissue viability imaging (TiVi) which measures concentration and oxygenation of red blood cells in the papillary dermis. Three studies were done with human subjects and one with an animal model, to validate and compare the TiVi technique with laser Doppler flowmetry, which is an established method of measuring dermal microcirculation.The TiVi consists of a digital camera with polarisation filters in front of the flash and lens, with software for analysis of the picture. When taking a picture with the TiVi, the polarised light that is reflected on the skin surface is absorbed by the second filter over the lens (which is perpendicular to the first filter) but a portion of light penetrates the surface of the skin and is scattered when it is reflected on tissue components. This makes the light depolarised, passes the second filter, and produces a picture for analysis. The red blood cell (RBC) has a distinct absorption pattern that differs between red and green colour compared to melanin and other components of tissue. This difference is used by the software that calculates differences in each picture element and produces a measure of output which is proportional to the concentration of red blood cells. The oxygenation of RBC can also be calculated, as there is a difference in absorption depending on oxygen state.The first paper takes up possible sources of error such as ambient light, and the angle and distance of the camera. The main experiment was to investigate how the local heating reaction is detected with TiVi compared to LDF.In the second paper arterial and venous stasis are examined in healthy subjects with TiVi.The Third paper is an animal study where skin flaps were raised on pigs, and the vascular pedicle is isolated to enable control of inflow and outflow of blood.The measurements were made during partial venous, total venous, and total arterial occlusion. The TiVi recorded changes in the concentration of RBC, oxygenation and heterogeneity and the results were compared with those of laser Doppler flowmetry.In the fourth paper oxygenation and deoxygenation of RBC: s was studied. Studies were made on the forearms of healthy subjects who were exposed to arterial and venous occlusion. Simultaneous measurements were made with TiVi and Enhanced perfusion and oxygen saturation or EPOS, which is a new device that combines laser Doppler flowmetry and diffuse reflectance spectroscopy in one probe.With TiVi, one can measure RBC concentration and oxygenation in the area of an entire picture or in one or multiple user defined regions of interest (ROI). Methods such as laser Doppler flowmetry makes single point measurements, which is a potential source of error both because of the heterogeneity of the microcirculation, and that the circulation be insufficient in the margins of the investigated area. TiVi has been able to measure venous stasis more accurately than laser Doppler flowmetry, and venous stasis is the more common reason for flaps to fail.The TiVi is an accurate way to measure the concentration of RBC and trends in oxygenation of the dermal microcirculation. It has interesting possible applications for microvascular and dermatological research, monitoring of flaps, and diagnosis of peripheral vascular disease. Future clinical studies are needed as well as development of the user interface.
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| 4. |
- Johansson, Gerd, et al.
(författare)
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Luftföroreningar vid svetsning
- 1978
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Beskrivning ges av utveckling av analysuppställning för PIXE-analys, kombinerad med metod för analys av fluor. Vidareutveckling av spektrumevalueringsprogram, HEX, presenteras. Beskrivning av utförda svetsröskarakteriseringar ges. Resultat redovisas för följande belagda elektroder: OK 48.00, OK 38.65 samt OK 61.41. För sistnämnda, rostfria elektrod, presenteras procedur för bestämning av kroms valenstal och löslighet.
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| 5. |
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| 6. |
- Sjöberg, Katrin, et al.
(författare)
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Measuring and using the RSSI of IEEE 802.11p
- 2010
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Ingår i: 17th World Congress on Intelligent Transport Systems, ITS 2010, Busan, South Korea, 25-29 October 2010.
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Konferensbidrag (refereegranskat)abstract
- The scalability of intelligent transport systems (ITS) applications is difficult to test in a field operational test (FOT) due to the high number of ITS equipped vehicles required. Therefore, computer simulations for evaluating different wireless communication technologies for ITS different applications can serve as a complement. In this paper we present results from lab measurements conducted on the CVIS hardware platform equipped with the upcoming standard IEEE 802.11p. We have measured the packet error rate versus the signal-to-noise ratio (SNR) for different packet lengths. This lab measurement is the first step towards an outdoor measurement campaign which also considers interference. The outdoor measurements will then be fed into a computer simulator together with a realistic channel model for evaluating the scalability of VANETs in a highway scenario.
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| 7. |
- Sjöberg, Thomas, et al.
(författare)
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Colorectal Cancer Cell Spheroids Co-Cultured with Molecularly Imprinted Fluorescent Particles Targeting Sialic Acid Show Preserved Cell Viability
- 2023
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Ingår i: Applied Sciences. - : MDPI. - 2076-3417. ; 13:9
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Tidskriftsartikel (refereegranskat)abstract
- In vitro cultured 3D models of CRC have been demonstrated to hold considerable worth in drug discovery, drug resistance analysis, and in studying cell-cell and cell-matrix interactions that occur in the tumor microenvironment. The 3D models resemble the in vivo physiological microenvironment by replicating the cell type composition and tissue architecture. Molecularly imprinted polymers (MIPs) have been investigated for use instead of antibodies against small non-immunogenic structures, such as sialic acid (SA). Glyco-conjugates including SA are present on all cells, and often deregulated on cancer cells. Here, we present a novel approach for targeting and detecting colorectal cancer cells (CRC) by using in vitro cultured HT29 3D spheroids co-cultured in vitro with either fluorescent MIPs targeting SA, SA-MIPs, or the two lectins targeting SA, MAL I, and SNA. Both formaldehyde-fixed and viable HT29 3D spheroids with or without SA-MIPs were imaged in 3D by confocal microscopy. The results revealed a preserved cell morphology and viability of the HT29 3D spheroids co-cultured in vitro with SA-MIPs. However, the lectins MAL I and SNA targeting the a-2,3 or a-2,6 SA glycosidic linkages, respectively, affected the cell viability when co-cultured with the viable HT29 3D spheroids, and no living cells could be detected. Here, we have shown that the SA-MIPs could be used as a safe and low-cost diagnostic tool for targeting and detecting cancer cells in a physiologically relevant 3D cancer model in vitro.
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| 8. |
- Turner, Charlotta, et al.
(författare)
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Subcritical water extraction and beta-glucosidase-catalyzed hydrolysis of quercetin glycosides in onion waste
- 2006
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Ingår i: Green Chemistry. - : Royal Society of Chemistry (RSC). - 1463-9262 .- 1463-9270. ; 8:11, s. 949-959
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Tidskriftsartikel (refereegranskat)abstract
- Onion waste is a renewable raw material, rich in different molecular species of the antioxidant quercetin. To utilize this resource, an environmentally sustainable procedure has been developed, using pressurized hot water to extract the quercetin species, followed by biocatalytic conversion of the quercetin glycosides to quercetin and carbohydrates. Two different recombinantly expressed thermostable beta-glucosidases, Thermotoga neapolitana beta-glucosidase A and B, were utilized as catalysts. These enzymes maintain activity at temperatures around 90 degrees C, and are therefore ideal to use in combination with hot water extraction. Our results, based on experimental design, showed that they converted quercetin glycosides to active quercetin in less than 10 min reaction time in water at 90 degrees C, pH 5.0. Experimental design showed that the optimal extraction conditions included three 5 min extraction cycles with water at 120 degrees C and 50 bars, giving a total extraction time of 15 min. Several different types of quercetin and isorhamnetin glycosides as well as kaempferol were detected in onion waste using LC-MS/MS analysis. After converting the different glycosidic compounds to their respective aglycones, the quercetin content was 10 to 50 mg g(-1) dry weight of onion waste (RSD 8%). In summary, our research demonstrates that subcritical water extraction followed by beta-glucosidase-catalyzed hydrolysis is a rapid method to determine the content of quercetin and isorhamnetin in onion samples, and is environmentally sustainable as it only uses water as solvent and enzymes as catalysts.
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