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High-angle deflection of metagrating-integrated laser emission for high-contrast microscopy

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Light(Science & Applications) 2023年第11期12卷 2434-2442页

作者： Mindaugas Juodėnas Erik Strandberg Alexander Grabowski Johan Gustavsson HanaŠípová-Jungová Anders larsson mikael Käll Department of Physics Chalmers University of Technology41296 GothenburgSweden Department of Microtechnology and Nanoscience Chalmers University of Technology41296 GothenburgSweden

Flat metaoptics components are looking to replace classical optics elements and could lead to extremely compact biophotonics devices if integrated with on-chip light sources and ***,using metasurfaces to shape light into wide angular range wavefronts with high efficiency,as is typically required in high-contrast microscopy applications,remains a *** we demonstrate curved GaAs metagratings integrated on vertical-cavity surface-emitting lasers(VCSELs)that enable on-chip illumination in total internal reflection and dark field *** on an unconventional design that circumvents the aspect ratio dependent etching problems in monolithic integration,we demonstrate off-axis emission centred at 60°in air and 63°in glass with>90%and>70%relative deflection efficiency,*** resulting laser beam is collimated out-of-plane but maintains Gaussian divergence in-plane,resulting in a long and narrow illumination *** show that metagrating-integrated VCSELs of different kinds can be combined to enable rapid switching between dark-field and total internal reflection *** approach provides a versatile illumination solution for high-contrast imaging that is compatible with conventional microscopy setups and can be integrated with biophotonics devices,such as portable microscopy,NIR-II range bioimaging,and lab-on-a-chip devices.

关键词： illumination deflection optics

Steroids reduce local inflammatory mediator secretion and mucosal permeability in collagenous colitis patients

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World Journal of Gastroenterology 2006年第43期12卷 7012-7018页

作者： Yesuf Taha Yngve Raab Marie Carlson Anders larsson mikael Lrdal Lars Lf Magnus Thrn Departments of Medical Sciences University Hospital Uppsala Sweden Department of Medicine KarolinskaInstitutet Karolinska University Hospital Huddinge Sweden Departments of Medical Sciences University Hospital Uppsala Sweden Departments of Clinical Chemistry University Hospital Uppsala Sweden Department of Medicine KarolinskaInstitutet Karolinska University Hospital Huddinge Sweden Center for Clinical Research Central Hospital Vsters Sweden Department of Surgery Karolinska Institutet South Stockholm General Hospital Stockholm Sweden

AIM：. To study the effect of oral steroids upon clinical response and rectal mucosa secretion of eosinophil cationic protein （ECP）, myeloperoxidase （NPO）, basic fibroblast growth factor （bFGF）, vascular endothelial growth factor （VEGF） and albumin in patients with collagenous colitis （CC）. METHODS： A segmental perfusion technique was used to collect perfusates from rectum of CC patients once before and twice （one and four weeks） after the start of steroid treatment. Clinical data was monitored and ECP, MPO, bFGF, VEGF and albumin concentrations were analyzed by immunochemical methods in perfusates and in serum. RESULTS： Steroids reduced the number of bowel movements by more than five times within one week and all patients reported improved subjective wellbeing at wk 1 and 4. At the same time, the median concentrations of ECP, bFGF, VEGF and albumin in rectal perfusates decreased significantly. MPO values were above the detection limit in only 3 patients before treatment and in none during treatment. VEGF, bFGF, ECP and albumin concentrations correlated with each other with the exception of ECP and albumin. A decrease of serum ECP and VEGF concentrations was also seen even if the overtime reduction was not significant.CONCLUSION： Oral steroid treatment in CC patients induced a simultaneous reduction of bowel movements and rectal release of ECP, bFGF, VEGF and albumin, suggesting that these polypeptides and increased mucosal permeability are important components of the pathophysiology in collagenous colitis.

关键词： Collagenous colitis Inflammatory mediator Steroid treatment Eosinophil cationic protein Basicfibroblast growth factor Vascular endothelial growthfactor

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Why do fish school？

Current Zoology 2012年第1期58卷 116-128页

作者： larsson, Matz The Cardiology Clinic Örebro University Hospital SE -701 85 Örebro Sweden The Institute of Environmental Medicine Karolinska Institute SE-171 77 Stockholm Sweden

Synchronized movements （schooling） emit complex and overlapping sound and pressure curves that might confuse the inner ear and lateral line organ （LLO） of a predator. Moreover, prey-fish moving close to each other may blur the elec- tro-sensory perception of predators. The aim of this review is to explore mechanisms associated with synchronous swimming that may have contributed to increased adaptation and as a consequence may have influenced the evolution of schooling. The evolu- tionary development of the inner ear and the LLO increased the capacity to detect potential prey, possibly leading to an increased potential for cannibalism in the shoal, but also helped small fish to avoid joining larger fish, resulting in size homogeneity and, accordingly, an increased capacity for moving in synchrony. Water-movements and incidental sound produced as by-product of locomotion （ISOL） may provide fish with potentially useful information during swimming, such as neighbour body-size, speed, and location. When many fish move close to one another ISOL will be energetic and complex. Quiet intervals will be few. Fish moving in synchrony will have the capacity to discontinue movements simultaneously, providing relatively quiet intervals to al- low the reception of potentially critical environmental signals. Besides, synchronized movements may facilitate auditory grouping of ISOL. Turning preference bias, well-functioning sense organs, good health, and skillful motor performance might be important to achieving an appropriate distance to school neighbors and aid the individual fish in reducing time spent in the comparatively less safe school periphery. Turning preferences in ancestral fish shoals might have helped fish to maintain groups and stay in for- mation, reinforcing aforementioned predator confusion mechanisms, which possibly played a role in the lateralization of the ver- tebrate brain [Current Zoology 58 （1）： 116-128, 2012].

关键词： Group synchrony Hearing in fish Lateral line Electro-sensory system Sensory reafference Lateralization

Scaling granular material with polygonal particles in discrete element modeling

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Particuology 2023年第4期75卷 151-164页

作者： Alireza Ahmadi Stefan larsson Carl Wersall KTH Royal Institute of Technology Division of Soil and Rock MechanicsBrinellvagen 2310044StockholmSweden

Despite advancements in computational resources,the discrete element method(DEM)still requires considerable computational time to solve detailed problems,especially when it comes to the large-scale *** addition to the geometry scale of the problem,the particle shape has a dramatic effect on the computational cost of ***,many studies have been performed with simplified spherical particles or *** scaling is an approach to increase the particle size to reduce the number of particles in the *** several particle scaling methods have been introduced,there are still some disagreements regarding their applicability to certain aspects of *** this study,the effect of particle scalping on the shear behavior of granular material is *** granular particles were scanned and imported as polygonal particles in the direct shear *** effect of particle size distri-bution,particle angularity,and the amount of scalping were *** results show that particle scalping can simulate the correct shear behavior of the model with significant improvement in computational ***,the accuracy of the scalping method depends on the particle angularity and particle size range.

关键词： Particle scaling Direct shear test Discrete element method PFC Polygonal shape Granular material

High performance highly strained InGaAs quantum-well ridge waveguide lasers

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Science China(Technological Sciences) 2005年第6期48卷 679-684页

作者： A. Uddin M. Sadeghi A. larsson School of Materials Engineering Nanyang Technological University Singapore 639798 Department of Microtechnology and Nanoscience Chalmers University of Technology S-412 96 Gte-borg Sweden

Highly strained InGaAs ridge waveguide lasers were fabricated with pulsed anodic oxidation. The laser structure was grown by molecular beam epitaxy (MBE) system. The output powers up to 50 mW per facet in CW mode were reached at room temperature for the 4 μm stripe lasers. The threshold current density of 300 A/cm2 was achieved with 600 μm cavity length. The emission wavelength at 100 mA was 1.19 μm. The slope efficiency was 0.45 W/A in linear output region of light-current characteristics. The laser characteristic temperature was 129 K (20°C–100°C).

关键词： highly strained, InGaAs quantum well, ridge waveguide lasers.

Spatial distribution modeling of subsurface bedrock using a developed automated intelligence deep learning procedure:A case study in Sweden

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Journal of Rock Mechanics and Geotechnical Engineering 2021年第6期13卷 1300-1310页

作者： Abbas Abbaszadeh Shahri Chunling Shan Emma Zall Stefan larsson Division of Rock Engineering Tyréns ABStockholmSweden Johan Lundberg AB UppsalaSweden Division of Soil and Rock Mechanics KTH Royal Institute of TechnologyStockholmSweden

Due to associated uncertainties,modelling the spatial distribution of depth to bedrock(DTB) is an important and challenging concern in many geo-engineering *** association between DTB,the safety and economy of design structures implies that generating more precise predictive models can be of vital *** the present study,the challenge of applying an optimally predictive threedimensional(3D) spatial DTB model for an area in Stockholm,Sweden was addressed using an automated intelligent computing design *** process was developed and programmed in both C++and Python to track their performance in specified tasks and also to cover a wide variety of diffe rent internal characteristics and *** comparison to the ordinary Kriging(OK) geostatistical tool,the superiority of the developed automated intelligence system was demonstrated through the analysis of confusion matrices and the ranked accuracies of different statistical *** re sults showed that in the absence of measured data,the intelligence models as a flexible and efficient alternative approach can account for associated uncertainties,thus creating more accurate spatial 3D models and providing an appropriate prediction at any point in the subsurface of the study area.

关键词： Automated intelligence system Predictive depth to bedrock(DTB)model Three-dimensional(3D)spatial distribution

Effects of spatial variation in cohesion over the concrete-rock interface on dam sliding stability

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Journal of Rock Mechanics and Geotechnical Engineering 2015年第6期7卷 659-667页

作者： Alexandra Krounis Fredrik Johansson Stefan larsson Division of Soil and Rock Mechanics KTH Royal Institute of Technology

The limit equilibrium method （LEM） is widely used for sliding stability evaluation of concrete gravitydams. Failure is then commonly assumed to occur along the entire sliding surface ***, the brittle behaviour of bonded concrete-rock contacts, in combination with the varying stressover the interface, implies that the failure of bonded dam-foundation interfaces occurs progressively. Inaddition, the spatial variation in cohesion may introduce weak spots where failure can be ***, the combined effect of brittle failure and spatial variation in cohesion on the overall shearstrength of the interface has not been studied previously. In this paper, numerical analyses are used toinvestigate the effect of brittle failure in combination with spatial variation in cohesion that is taken intoaccount by random fields with different correlation lengths. The study concludes that a possible existenceof weak spots along the interface has to be considered since it significantly reduces the overallshear strength of the interface, and implications for doing so are discussed.

关键词： Concrete gravity dam Sliding stability Cohesion Brittle failure Spatial variation

Automatic Delineation of the Clinical Target Volume and Organs at Risk in Rectal Cancer for Radiation Therapy Using Three-Dimensional Fully Convolutional Neural Networks

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Automatic Delineation of the Clinical Target Volume and Orga...

作者： Rasmus larsson 上海交通大学

学位级别：硕士

Rectal cancer is one of the forms of cancer that kills the highest amount of people every *** a disease,rectal cancer is highly complex with many factors deciding the outcome of the patient’s *** complexity mandates a multi-modality approach in its *** consensus in the medical community is to attack the cancer with a combination of surgery,chemotherapy,and radiation *** exact combination is a point of controversy and largely depend on the cancer *** therapy has nonetheless been shown to significantly reduce local recurrence rate in late stage rectal cancer if administered preoperatively.A major difficulty in radiation therapy planning is the proper delineation of the cancerous tissue for energy beam *** target volume（CTV）delineation is riddled with problems such as poor reproducibility and high time *** process of target volume delineation is traditionally done by radiation oncologists with years of *** alleviate their work burden,automatic segmentation software were *** available software for this purpose are currently dominated by algorithms based on one or many atlases used for registration to estimate the target *** deep learning algorithms,like convolutional neural networks（CNNs）,that are trained in a supervised fashion show potent results in medical image segmentation ***,their application in radiation therapy planning is *** few networks that have been investigated all utilize two-dimensional *** improve the performance,a three-dimensional network is therefore used in this *** West China Hospital provided the study with 379 CT scans with accompanying ground truth delineations of relevant region of interests（ROIs）performed by experienced radiation *** this workflow,65%of the provided CT scans were used for training of the network and the remaining 35%for *** 3D CNN used was the V-net and to test its feasibil

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Automatic Detection of Lung Nodules Using 3D Deep Convolutional Neural Networks

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Journal of Shanghai Jiaotong university(Science) 2019年第4期24卷 517-523页

作者： FU Ling MA Jingchen CHEN Yizhi larsson Rasmus ZHAO Jun School of Biomedical Engineering Shanghai Jiao Tong UniversityShanghai200240China SJTU-UIH Institute for Medical Imaging Technology Shanghai Jiao Tong UniversityShanghai200240China MED-X Research Institute Shanghai Jiao Tong UniversityShanghai200030China School of Technology and Health KTH Royal Institute of TechnologySE-10044StockholmSweden

Lung cancer is the leading cause of cancer deaths worldwide. Accurate early diagnosis is critical in increasing the 5-year survival rate of lung cancer, so the efficient and accurate detection of lung nodules,the potential precursors to lung cancer, is paramount. In this paper, a computer-aided lung nodule detection system using 3D deep convolutional neural networks(CNNs) is developed. The first multi-scale 11-layer 3D fully convolutional neural network(FCN) is used for screening all lung nodule candidates. Considering relative small sizes of lung nodules and limited memory, the input of the FCN consists of 3D image patches rather than of whole images. The candidates are further classified in the second CNN to get the final result. The proposed method achieves high performance in the LUNA16 challenge and demonstrates the effectiveness of using 3D deep CNNs for lung nodule detection.

关键词： lung nodule detection computer-aided detection (CAD) convolutional neural network (CNN) fully convolutional neural network (FCN)