| 1. |
- Bartkowiak, T., et al.
(författare)
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Establishing functional correlations between multiscale areal curvatures and coefficients of friction for machined surfaces
- 2018
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Ingår i: Surface Topography: Metrology and Properties. - 2051-672X. ; 6:3
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Tidskriftsartikel (refereegranskat)abstract
- The objective of this research is to determine the strengths of correlation, and their variation with scale, between friction coefficients and topographic characterization parameters, calculated using statistical representations of multiscale areal curvatures. The surfaces are created by milling and manual polishing. Coefficients of friction were measured during bending under tension tests. Surfaces were measured with a white light interferometer. Curvature tensors were calculated using a normal based method adapted for multiscale analysis. Three different regions were analyzed from each of eight samples. Curvature tensor parameters: principal, mean, and Gaussian curvatures were calculated for scales between 0.78 and 47.08 μm. These statistical measures of the curvatures were regressed against the coefficient of friction. Three different analyses were performed, taking into account entire curvature distributions, only negative or positive values and curvatures of top heights. Strong correlations (R2 > 0.85 for many and as large as 0.96) were found for the standard deviations for all four curvature measures when entire distributions were considered. These results suggest that the frictional responses of surfaces could be related to the variance of their topographic curvatures. Average curvature parameters correlate strongly with coefficients of friction for negative values. Curvatures calculated from top regions present strong correlations for both mean and standard deviation of maximal, mean and Gaussian curvatures. This supports the use of multiscale curvature tensor methods for characterizing interactions between surface topography and tribological performance.
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| 2. |
- Berglund, E Carina, et al.
(författare)
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Oral administration of methylphenidate blocks the effect of cocaine on uptake at the Drosophila dopamine transporter.
- 2013
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Ingår i: ACS chemical neuroscience. - : American Chemical Society (ACS). - 1948-7193. ; 4:4, s. 566-74
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Tidskriftsartikel (refereegranskat)abstract
- Although our understanding of the actions of cocaine in the brain has improved, an effective drug treatment for cocaine addiction has yet to be found. Methylphenidate binds the dopamine transporter and increases extracellular dopamine levels in mammalian central nervous systems similar to cocaine, but it is thought to elicit fewer addictive and reinforcing effects owing to slower pharmacokinetics for different routes of administration between the drugs. This study utilizes the fruit fly model system to quantify the effects of oral methylphenidate on dopamine uptake during direct cocaine exposure to the fly CNS. The effect of methylphenidate on the dopamine transporter has been explored by measuring the uptake of exogenously applied dopamine. The data suggest that oral consumption of methylphenidate inhibits the Drosophila dopamine transporter and the inhibition is concentration dependent. The peak height increased to 150% of control when cocaine was used to block the dopamine transporter for untreated flies but only to 110% for methylphenidate-treated flies. Thus, the dopamine transporter is mostly inhibited for the methylphenidate-fed flies before the addition of cocaine. The same is true for the rate of the clearance of dopamine measured by amperometry. For untreated flies the rate of clearance changes 40% when the dopamine transporter is inhibited with cocaine, and for treated flies the rate changes only 10%. The results were correlated to the in vivo concentration of methylphenidate determined by CE-MS. Our data suggest that oral consumption of methylphenidate inhibits the Drosophila dopamine transporter for cocaine uptake, and the inhibition is concentration dependent.
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| 3. |
- Berglund, Johan C, 1978, et al.
(författare)
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Milled die steel surface roughness correlation with steel sheet friction
- 2010
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Ingår i: CIRP Annals - Manufacturing Technology. - Bern : Elsevier BV. - 1726-0604 .- 0007-8506. ; 59:1, s. 577-580
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Konferensbidrag (refereegranskat)abstract
- This work investigates correlations between the surface topography of milled steel dies and friction with steel sheet. Several die surfaces were prepared by milling. Friction was measured in bending under tension testing. Linear regression coefficients (R^2) between the friction and texture characterization parameters were tested. None of the height, spacing, material volume, void or segmentation parameters showed good correlations. Developed area, rms surface gradient, relative area and complexity showed strong correlations (R^2 > 0.7). For area-scale fractal complexity the correlation increases markedly at scales below 200 μm^2, with a maximum R^2 of 0.9 at 50 μm^2.
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| 4. |
- Berglund, Johan C, 1978, et al.
(författare)
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On discovering relevant scales in surface roughness measurement : an evaluation of a band-pass method
- 2010
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Ingår i: Scanning. - London : John Wiley & Sons. - 0161-0457 .- 1932-8745. ; 32:4, s. 244-249
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Tidskriftsartikel (refereegranskat)abstract
- When characterizing surfaces and searching for correlations to functional properties, such as friction, finding the right scale of roughness for evaluation can improve correlations. However, in traditional roughness parameter analysis, a wide range of scales, or all scales of topography in the surface roughness measurements are evaluated together. In this study a multi-scale method using a series of band-pass filters is employed for finding scales of topography with strong correlations to friction.
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| 5. |
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| 6. |
- Brown, Christopher A., et al.
(författare)
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Multiscale analyses and characterizations of surface topographies
- 2018
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Ingår i: CIRP Annals - Manufacturing Technology. - : Elsevier BV. - 1726-0604 .- 0007-8506. ; 67:2, s. 839-862
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Tidskriftsartikel (refereegranskat)abstract
- This work studies multiscale analyses and characterizations of surface topographies from the engineering and scientific literature with an emphasis on production engineering research and design. It highlights methods that provide strong correlations between topographies and performance or topographies and processes, and methods that can confidently discriminate topographies that were processed or that perform differently. These methods have commonalities in geometric characterizations at certain scales, which are observable with statistics and measurements. It also develops a semantic and theoretical framework and proposes a new system for organizing and designating multiscale analyses. Finally, future possibilities for multiscale analyses are discussed.
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| 7. |
- Gaines, Hans, et al.
(författare)
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Six-week follow-up after HIV-1 exposure: a position statement from the Public Health Agency of Sweden and the Swedish Reference Group for Antiviral Therapy
- 2016
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Ingår i: Infectious Diseases. - : Informa UK Limited. - 2374-4235 .- 2374-4243. ; 48:2, s. 93-98
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Forskningsöversikt (refereegranskat)abstract
- In 2014 the Public Health Agency of Sweden and the Swedish Reference Group for Antiviral Therapy (RAV) conducted a review and analysis of the state of knowledge on the duration of follow-up after exposure to human immunodeficiency virus (HIV). Up until then a follow-up of 12 weeks after exposure had been recommended, but improved tests and new information on early diagnosis motivated a re-evaluation of the national recommendations by experts representing infectious diseases and microbiology, county medical officers, the RAV, the Public Health Agency, and other national authorities. Based on the current state of knowledge the Public Health Agency of Sweden and the RAV recommend, starting in April 2015, a follow-up period of 6 weeks after possible HIV-1 exposure, if HIV testing is performed using laboratory-based combination tests detecting both HIV antibody and antigen. If point-of-care rapid HIV tests are used, a follow-up period of 8 weeks is recommended, because currently available rapid tests have insufficient sensitivity for detection of HIV-1 antigen. A follow-up period of 12 weeks is recommended after a possible exposure for HIV-2, since presently used assays do not include HIV-2 antigens and only limited information is available on the development of HIV antibodies during early HIV-2 infection. If pre- or post-exposure prophylaxis is administered, the follow-up period is recommended to begin after completion of prophylaxis. Even if infection cannot be reliably excluded before the end of the recommended follow-up period, HIV testing should be performed at first contact for persons who seek such testing.
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| 8. |
- Hentati-Sundberg, Jonas, et al.
(författare)
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Seabird surveillance: combining CCTV and artificial intelligence for monitoring and research
- 2023
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Ingår i: Remote Sensing in Ecology and Conservation. - : Wiley. - 2056-3485. ; 9:4, s. 568-581
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Tidskriftsartikel (refereegranskat)abstract
- Ecological research and monitoring need to be able to rapidly convey information that can form the basis of scientifically sound management. Automated sensor systems, especially if combined with artificial intelligence, can contribute to such rapid high-resolution data retrieval. Here, we explore the prospects of automated methods to generate insights for seabirds, which are often monitored for their high conservation value and for being sentinels for marine ecosystem changes. We have developed a system of video surveillance combined with automated image processing, which we apply to common murres Uria aalge. The system uses a deep learning algorithm for object detection (YOLOv5) that has been trained on annotated images of adult birds, chicks and eggs, and outputs time, location, size and confidence level of all detections, frame-by-frame, in the supplied video material. A total of 144 million bird detections were generated from a breeding cliff over three complete breeding seasons (2019–2021). We demonstrate how object detection can be used to accurately monitor breeding phenology and chick growth. Our automated monitoring approach can also identify and quantify rare events that are easily missed in traditional monitoring, such as disturbances from predators. Further, combining automated video analysis with continuous measurements from a temperature logger allows us to study impacts of heat waves on nest attendance in high detail. Our automated system thus produces comparable, and in several cases significantly more detailed, data than those generated from observational field studies. By running in real time on the camera streams, it has the potential to supply researchers and managers with high-resolution up-to-date information on seabird population status. We describe how the system can be modified to fit various types of ecological research and monitoring goals and thereby provide up-to-date support for conservation and ecosystem management.
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| 9. |
- Majdi, Soodabeh, 1980, et al.
(författare)
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Electrochemical Measurements of Optogenetically Stimulated Quantal Amine Release from Single Nerve Cell Varicosities in Drosophila Larvae
- 2015
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Ingår i: Angewandte Chemie International Edition. - : Wiley. - 1433-7851 .- 1521-3773. ; 54:46, s. 13609-13612
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Tidskriftsartikel (refereegranskat)abstract
- The nerve terminals found in the body wall of Drosophila melanogaster larvae are readily accessible to experimental manipulation. We used the light-activated ion channel, channelrhodopsin-2, which is expressed by genetic manipulation in TypeII varicosities to study octopamine release in Drosophila. We report the development of a method to measure neurotransmitter release from exocytosis events at individual varicosities in the Drosophila larval system by amperometry. A microelectrode was placed in a region of the muscle containing a varicosity and held at a potential sufficient to oxidize octopamine and the terminal stimulated by blue light. Optical stimulation of TypeII boutons evokes exocytosis of octopamine, which is detected through oxidization at the electrode surface. We observe 22700 +/- 4200 molecules of octopamine released per vesicle. This system provides a genetically accessible platform to study the regulation of amine release at an intact synapse.
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| 10. |
- Makos, Monique A., et al.
(författare)
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Chemical measurements in Drosophila
- 2009
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Ingår i: TrAC - Trends in Analytical Chemistry. - 0165-9936. ; 28:11, s. 1223-1234
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Tidskriftsartikel (refereegranskat)abstract
- The fruit fly, Drosophila melanogaster, has been extensively used as a model organism in genetics research and has significantly contributed to understanding molecular, cellular and evolutionary aspects of human behavior. Recently, research has focused on developing analytical methods to obtain highly sensitive chemical quantification along with spatiotemporal information from Drosophila melanogaster. We review a number of these advances in capillary electrophoresis, high-performance liquid chromatography, mass spectrometry, and technologies involving intact organisms, including in vivo electrochemistry.
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