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  • 3151.
    Xia, Wei
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Qin, Tao
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Suska, Felicia
    Engqvist, Håkan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Bioactive spheres: the way of treating dentin hypersensitivity2016Inngår i: ACS biomaterials science and engineering, ISSN 2373-9878, Vol. 2, nr 5, s. 734-740Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Sealing exposed dental tubules is the most effective and long-term way to relieve the pain induced by dental sensitivity. A bioactive hollow sphere (strontium substituted calcium phosphate) was synthesized and added in toothpaste to study its effect on dental hypersensitivity via tooth tubules occlusion and mineralization. The size of spheres is perfect for penetrating into dental tubules, reaching to 20 pm into the tubules. The exposed dental tubules were occluded by spheres and new apatite layer after 3 days brushing. The spheres attached to the surface of dentin and the mineralized surface contained two layers, a porous layer followed by a dense apatite layer. The porous layer can be dissolved in an acidic solution, but the following dense layer could be kept even after soaking in an acid solution. In conclusion, Sr-substituted calcium phosphate spheres could be a good candidate for at-home treatment of dental hypersensitivity.

  • 3152.
    Xie, Haiyan
    et al.
    Dept. of Physics, Lund University, Sweden.
    Haj-Hosseini, Neda
    Linköpings universitet, Institutionen för medicinsk teknik, Biomedicinsk instrumentteknik. Linköpings universitet, Tekniska högskolan.
    Richter, Johan
    Linköpings universitet, Institutionen för medicinsk teknik. Linköpings universitet, Tekniska högskolan. Östergötlands Läns Landsting, Sinnescentrum, Neurokirurgiska kliniken US.
    Wårdell, Karin
    Linköpings universitet, Institutionen för medicinsk teknik, Biomedicinsk instrumentteknik. Linköpings universitet, Tekniska högskolan.
    Andersson-Engels, Stefan
    Dept. of Physics, Lund University, Sweden.
    Fluorescence spectroscopy for guiding malignant brain tumour resection with Optical Touch Pointer2010Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Glioblastoma multiforme (GBM), a highly malignant primary brain tumor, is difficult to distinguish from from its surrounding functioning tissue under direct vision in the operating field, since it grows in an infiltrative growth pattern. The main challenge in the surgical treatment of GBM is to fully resect the tumor and avoid neurological impairment. In this paper we extend previous proof-of-principle studies by extending the clinical potential of OTP with the introduction of more sophisticated multivariate analysis schemes. The aim is to distinguish tumor and healthy tissue as well as possible using singular value decomposition (SVD) and cluster analysis methods.

  • 3153. Xie, L.
    et al.
    Zheng, Li-rong
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Industriell och Medicinsk Elektronik.
    Yang, G.
    Hybrid integration technology for wearable sensor systems2016Inngår i: Internet of Things and Advanced Application in Healthcare, IGI Global , 2016, s. 98-137Kapittel i bok, del av antologi (Annet vitenskapelig)
    Abstract [en]

    Personalized and pervasive healthcare devices help seamlessly integrate healthcareand wellness into the daily life, independent of time and space. Silicon IntegratedCircuit (IC) has been used in many advanced healthcare applications due to thecompact size and ultra-low power consumption. Meanwhile, printed electronics(PE) is considered as a promising approach enabling cost-effective manufacturingof thin, flexible, and light-weight devices. A hybrid integration of IC and PE providesa new solution for the future wearable healthcare devices. In this chapter, firstlya customized bio-sensing IC is demonstrated, which can detect and process variousbio-signals; secondly, the feasibility and performance of using inkjet printingtechnology as enabling technology has been examined for the fabrication of flexiblebio-sensing devices. Finally, a wearable and flexible Bio-Patch is presented byleveraging hybrid integration of PE and bio-sensing IC. In-vivo test results showthat the flexible Bio-Patch provides high quality ECG signal comparable with theone gained by bedside ECG machine.

  • 3154.
    Xie, Li
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Elektroniksystem. KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, VinnExcellence Center for Intelligence in Paper and Packaging, iPACK.
    Yang, Geng
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Elektroniksystem. KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, VinnExcellence Center for Intelligence in Paper and Packaging, iPACK.
    Xu, Linlin
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, VinnExcellence Center for Intelligence in Paper and Packaging, iPACK.
    Seoane, Fernando
    KTH, Skolan för teknik och hälsa (STH), Medicinsk teknik, Medicinska sensorer, signaler och system.
    Chen, Qiang
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Elektroniksystem. KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, VinnExcellence Center for Intelligence in Paper and Packaging, iPACK.
    Zheng, Lirong
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Elektroniksystem. KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, VinnExcellence Center for Intelligence in Paper and Packaging, iPACK. State Key Laboratory of ASICs and Systems, Fudan University, 200433, Shanghai, China .
    Characterization of dry biopotential electrodes2013Inngår i: Proceedings of the Annual International Conference of the IEEE Engineering in Medicine and Biology Society, EMBS, 2013, s. 1478-1481Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Driven by the increased interest in wearable long-term healthcare monitoring systems, varieties of dry electrodes are proposed based on different materials with different patterns and structures. Most of the studies reported in the literature focus on proposing new electrodes and comparing its performance with commercial electrodes. Few papers are about detailed comparison among different dry electrodes. In this paper, printed metal-plate electrodes, textile based electrodes, and spiked electrodes are for the first time evaluated and compared under the same experimental setup. The contact impedance and noise characterization are measured. The in-vivo electrocardiogram (ECG) measurement is applied to evaluate the overall performance of different electrodes. Textile electrodes and printed electrodes gain comparable high-quality ECG signals. The ECG signal obtained by spiked electrodes is noisier. However, a clear ECG envelope can be observed and the signal quality can be easily improved by backend signal processing. The features of each type of electrodes are analyzed and the suitable application scenario is addressed.

  • 3155.
    Xie, Yuting
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska fakulteten. Sichuan University.
    An Automatic Localization Algorithm for Ultrasound Breast Tumors Based on Human Visual Mechanism2017Inngår i: Sensor of Journals, ISSN 1424-8220, Vol. 17, nr 5Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Human visual mechanisms (HVMs) can quickly localize the most salient object in natural images, but it is ineffective at localizing tumors in ultrasound breast images. In this paper, we research the characteristics of tumors, develop a classic HVM and propose a novel auto-localization method. Comparing to surrounding areas, tumors have higher global and local contrast. In this method, intensity, blackness ratio and superpixel contrast features are combined to compute a saliency map, in which a Winner Take All algorithm is used to localize the most salient region, which is represented by a circle. The results show that the proposed method can successfully avoid the interference caused by background areas of low echo and high intensity. The method has been tested on 400 ultrasound breast images, among which 376 images succeed in localization. This means this method has a high accuracy of 94.00%, indicating its good performance in real-life applications. 

  • 3156. Xing, Zhe
    et al.
    Xue, Ying
    Dånmark, Staffan
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik.
    Finne-Wistrand, Anna
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik.
    Arvidson, Kristina
    Hellem, Solve
    Yang, Zhuang-Qun
    Mustafa, Kamal
    Comparison of short-run cell seeding methods for poly(L-lactide-co-1,5-dioxepan-2-one) scaffold intended for bone tissue engineering2011Inngår i: International Journal of Artificial Organs, ISSN 0391-3988, E-ISSN 1724-6040, Vol. 34, nr 5, s. 432-441Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Constructs intended for bone tissue engineering are influenced by the initial cell seeding procedure. The seeding method should be rapid, convenient, improve cell spatial distribution, and have no negative effects on cellular viability and differentiation. This study aimed to compare the effect of short-run seeding methods (centrifuge and vortex) with a static method on the scaffolds prepared from poly(L-lactide-co-1,5-dioxepan-2-one) by solvent-casting particulate-leaching (SCPL) technique. Human osteoblast-like cells (HOB) were seeded by the three methods described above. The seeding efficiency was determined by attached cell numbers. Cellular proliferation was analyzed by WST-1 and dsDNA assay. Cell distribution was examined by scanning electron (SEM) and fluorescence microscopy. Expression of Alkaline Phosphatase (ALP), Collagen type I (Col I), Osteocalcin (OC) and Proliferating Cell Nuclear Antigen (PCNA) were determined by real time RT-PCR. Results indicated that centrifuge and vortex increased seeding efficiency and had no negative effects on cellular viability. The data obtained by the fluorescence microscope confirmed the SEM results that the vortex method improved cell distribution through the scaffolds more than the other two methods (p<0.05). The RT-PCR results showed no significant differences on the expression of mRNA between the three methods of the above markers. The vortex method was found to be a simple and feasible seeding method for the poly(L-lactide-co-1,5-dioxepan-2-one) scaffolds.

  • 3157. Xiong, Changsheng
    et al.
    Sjöberg, Birgitta Janero
    Linköpings universitet, Institutionen för medicin och hälsa, Klinisk fysiologi. Linköpings universitet, Hälsouniversitetet. Linköpings universitet, Centrum för medicinsk bildvetenskap och visualisering, CMIV. Östergötlands Läns Landsting, Hjärt- och Medicincentrum, Fysiologiska kliniken US.
    Sveider, Per
    Linköpings universitet, Institutionen för medicinsk teknik.
    Ask, Per
    Linköpings universitet, Institutionen för medicinsk teknik, Fysiologisk mätteknik. Linköpings universitet, Tekniska högskolan.
    Loyd, Dan
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Mekanisk värmeteori och strömningslära. Linköpings universitet, Tekniska högskolan.
    Wranne, Bengt
    Linköpings universitet, Institutionen för medicin och vård, Klinisk fysiologi. Linköpings universitet, Hälsouniversitetet. Östergötlands Läns Landsting, Hjärt- och Medicincentrum, Fysiologiska kliniken US.
    Problems in timing of respiration with the nasal thermistor technique.1993Inngår i: Journal of the American Society of Echocardiography, ISSN 0894-7317, E-ISSN 1097-6795, Vol. 6, nr 2, s. 210-216Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    When one analyzes transvalvular and venous flow velocity patterns, it is important to relate them to respiration. For this reason a nasal thermistor technique is often used, although it is known that this signal is delayed in relation to intrathoracic pressure changes. The magnitude and variation in delay have not been investigated previously and were, therefore, studied in a model experiment in 10 normal subjects, in 10 patients with obstructive, and in 10 patients with restrictive pulmonary disease. Esophageal pressure variations measured with an air-filled balloon served as a gold standard for intrathoracic pressure changes. During basal conditions there was, for both patient groups and normal subjects, a considerable delay of the thermistor signal. The average delay for all subjects was 370 msec with a wide variation (from 120 to 720 msec). At higher breathing frequencies the delay shortened to 310 msec (P < 0.01) but there was still a wide variation (ranging from 200 to 470 msec). Theoretic calculations show that the delay caused by the respiratory system accounts for only a minor portion of the total delay. Model experiments confirmed that the response characteristics of the thermistor probes limit the accuracy in timing of respiration. The total delay with the investigated thermistor technique is too long and variable to fulfil clinical demands.

  • 3158.
    Xu, Cheng
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Medicinsk avbildning.
    A Segmented Silicon Strip Detector for Photon-Counting Spectral Computed Tomography2012Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Spectral computed tomography with energy-resolving detectors has a potential to improve the detectability of images and correspondingly reduce the radiation dose to patients by extracting and properly using the energy information in the broad x-ray spectrum. A silicon photon-counting detector has been developed for spectral CT and it has successfully solved the problem of high photon flux in clinical CT applications by adopting the segmented detector structure and operating the detector in edge-on geometry. The detector was evaluated by both the simulation and measurements.

    The effects of energy loss and charge sharing on the energy response of this segmented silicon strip detector with different pixel sizes were investigated by Monte Carlo simulation and a comparison to pixelated CdTe detectors is presented. The validity of spherical approximations of initial charge cloud shape in silicon detectors was evaluated and a more accurate statistical model has been proposed.

    A photon-counting energy-resolving application specific integrated circuit (ASIC) developed for spectral CT was characterized extensively by electrical pulses, pulsed laser and real x-ray photons from both the synchrotron and an x-ray tube. It has been demonstrated that the ASIC performs as designed. A noise level of 1.09 keV RMS has been measured and a threshold dispersion of 0.89 keV RMS has been determined. The count rate performance of the ASIC in terms of count loss and energy resolution was evaluated by real x-rays and promising results have been obtained.

    The segmented silicon strip detector was evaluated using synchrotron radiation. An energy resolution of 16.1% has been determined with 22 keV photons in the lowest flux limit, which deteriorates to 21.5% at an input count rate of 100 Mcps mm−2. The fraction of charge shared events has been estimated and found to be 11.1% for 22 keV and 15.3% for 30 keV. A lower fraction of charge shared events and an improved energy resolution can be expected by applying a higher bias voltage to the detector.

  • 3159.
    Xu, Cheng
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Medicinsk avbildning.
    Danielsson, Mats
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Medicinsk avbildning.
    Karlsson, Staffan
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Medicinsk avbildning.
    Svensson, Christer
    Bornefalk, Hans
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Medicinsk avbildning.
    Preliminary evaluation of a silicon strip detector for photon-counting spectral CT2012Inngår i: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, ISSN 0168-9002, E-ISSN 1872-9576, Vol. 677, s. 45-51Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    An edge-on silicon strip detector designed for photon-counting spectral computed tomography (CT) is presented. Progress on the development of an application specific integrated circuit (ASIC) to process the pulses and sort them into energy bins is reported upon. The ASIC and detector are evaluated in terms of electronic noise, energy resolution, count rate linearity under high-frequency periodic pulses, threshold variation and gain. The high-frequency periodic pulses are injected both by means of an external pulse generator and a pulsed laser illuminating the silicon diode. The pulsed laser system has similar to 100 ps pulse width and thus generates near instantaneous pulses in the diode, thus mimicking real X-ray conversions. The evaluation shows a low thermal noise level of 0.77 key RMS, an energy resolution of 1.5 keV RMS when electron-hole pairs are generated in the detector diode by the laser injection. The test results furthermore indicate a good energy-discriminating capability of the detector with the thresholds spread out, assigning the external pulses to higher and higher energy bins as the pulse intensity is increased.

  • 3160.
    Xu, Jia Cheng
    et al.
    KTH, Skolan för teknik och hälsa (STH).
    Jildenbäck, Manne
    KTH, Skolan för teknik och hälsa (STH).
    Förbättring av energieffektivitet vid gång: En studie på patienter med höftledsartros efter total höftledsplastik2017Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [en]

    Hip osteoarthritis is a common disease associated with everyday pain and limited mobility. This causes a change in gait characteristics during walking, which tends to give a lower energy efficiency than normal. For patients with hip osteoarthritis, hip arthroplasty is considered a last option due to the related risks of a surgery.

    To investigate whether the patients show signs of improvement after the surgery, through an energy efficiency standpoint, data have been collected through a gait analysis. In this study, gait analysis was performed on a healthy reference group to obtain reference data. Data from the patient group, which consisted of patients with hip osteoarthritis pre- and post surgery using total hip arthroplasty, THA, was given by Karolinska Institutet. To determine if THA is an appropriate action, data from the patients were compared to the reference data.

    By performing and collecting data through a gait analysis on a healthy reference group and on patients with hip osteoarthritis pre- and post surgery using total hip arthroplasty, THA, this study has investigated whether the patients show signs of improvement after the surgery and also if the patients differentiate from the reference group through an energy efficiency standpoint. This is used to determine whether THA is an appropriate action.

     The study showed a difference in energy efficiency pre- and post surgery. An obvious improvement after THA was shown in most of the patients (p = 0,0094). However, 36 % showed in at least one case, decreased- or an unchanged value in energy efficiency. Although, through an average standpoint only two patients showed decreased efficiency, but the patients after THA only reached an energy efficiency that was approximately half the efficiency of the reference group.

    The results in this study indicates that further studies are necessary. Considerable alternatives to THA, especially surface hip arthroplasty, SRA, as well as parameters such as pain and mobility should be examined with respect to energy efficiency. Until then, hip arthroplasty should still be considered a last option for patients.

  • 3161.
    Xu, Jiahua
    et al.
    Sahlgrenska University Hospital, Göteborg.
    Moonen, Mchaela
    Sahlgrenska University Hospital, Göteborg.
    Johansson, Åke
    Sahlgrenska University Hospital, Göteborg.
    Gustafsson, Agnetha
    Sahlgrenska University Hospital, Göteborg.
    Bake, Björn
    Sahlgrenska University Hospital, Göteborg.
    Quantitative analysis of inhomogeneity in ventilation SPET2001Inngår i: European Journal of Nuclear Medicine, ISSN 0340-6997, E-ISSN 1432-105X, Vol. 28, nr 12, s. 1795-1800Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The aim of this study was to evaluate a method for quantification of inhomogeneity in ventilation single-photon emission tomography (SPET). Nine emphysematous patients, nine life-long non-smokers and nine smokers were included in the study. The SPET investigation was performed after 50 MBq (99m)Tc-Technegas had been inhaled by each subject in the supine position. A single-head gamma camera, equipped with a general-purpose parallel-hole collimator using 64 projections (20 s each) over 360 degrees, was used. Data were acquired in 128x128 matrices. Attenuation correction was applied based upon computed tomography (CT) density maps. Lung regions of interest were delineated manually on CT images and then positioned on SPET images. Several attenuation-corrected transaxial SPET slices (thickness 1 cm, spacing 3.5 cm) were reconstructed. Each SPET slice was divided into several 2x2x1 cm(3) elements. Inhomogeneity was assessed by the coefficient of variation (CV) of the pixel counts within these elements (micro-level) and the CV of the total counts of the elements (macro-level). Micro-level CVs in non-smokers varied between 1% and 41%, whereas they were dispersed over a wide range (1%-600%) in emphysematous patients. In seven smokers, the frequency distribution of micro-level CVs was within the normal range, whereas in the other two smokers the values were between the normal range and the range in emphysematous patients. The pooled mean values of micro-level CVs and macro-level CVs in each subject clearly separated the patients from the others. Parametric images of micro-level CV indicated the localisation and severity of ventilation inhomogeneity. We conclude that the present method enables quantification and localisation of regional inhomogeneity in ventilation SPET images.

  • 3162.
    Xu, Jiahua
    et al.
    Sahlgrenska University Hospital, Göteborg.
    Moonen, Michaela
    Sahlgrenska University Hospital, Göteborg.
    Johansson, Åke
    Sahlgrenska University Hospital, Göteborg.
    Gustafsson, Agnetha
    Linköpings universitet, Institutionen för medicin och hälsa, Medicinsk radiofysik. Linköpings universitet, Hälsouniversitetet. Östergötlands Läns Landsting, Centrum för kirurgi, ortopedi och cancervård, Radiofysikavdelningen US.
    Bake, Björn
    Sahlgrenska University Hospital, Göteborg.
    Quantitative analysis oh inhomogenity in ventilation SPECT2002Konferansepaper (Annet vitenskapelig)
  • 3163.
    Xu, Jin Wei
    et al.
    Bioinformatics Research Group School of Engineering and Information Technology The University of New South Wales Canberra, ACT 2600, Australia .
    Pham, Tuan D.
    Bioinformatics Research Group School of Engineering and Information Technology The University of New South Wales Canberra, Australia .
    Zhou, Xiaobo
    The Methodist Hospital Research Institute Cornell University Houston, TX 77030, USA.
    A double thresholding method for cancer stem cell detection2011Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Image analysis of cancer cells is important for cancer diagnosis and therapy, because it recognized as the most efficient and effective way to observe its proliferation. For the purpose of adaptive and accurate cancer cell image segmentation, a double threshold segmentation method is proposed in this paper. Based on a single gray-value histogram of the RGB color space, a double threshold, the key parameters of threshold segmentation can be fixed by a fitted-curve of the RGB component histogram. As reasonable thresholds confirmed, binary segmentation dependent on two thresholds, will be put into practice and result in binary image. With the post-processing of mathematical morphology and division of whole image, the better segmentation result can be finally achieved. By the comparison with other advanced segmentation methods such as level set and active contour, the proposed double thresholding has been found as the simplest strategy with shortest processing time as well as highest accuracy. The proposed method can be effectively used in the detection and recognition of cancer stem cells in images.

  • 3164.
    Xu, Jinwei
    et al.
    School of Engineering and Information Technology, The University of New South Wales, Canberra, Australia.
    Pham, Tuan D
    School of Computer Science and Engineering, Research Center for Advanced Information Science and Technology, The University of Aizu, Aizu-Wakamatsu City, Fukushima, Japan.
    Robust impulse-noise filtering for biomedical images using numerical interpolation2012Inngår i: Image Analysis and Recognition: 9th International Conference, ICIAR 2012, Aveiro, Portugal, June 25-27, 2012. Proceedings, Part II / [ed] Aurélio Campilho; Mohamed Kamel, Springer Berlin/Heidelberg, 2012, s. 146-155Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Analysis of molecular and medical images is an important area of interdisciplinary research. Accurate interpretation and understanding of those images is increasingly demanding because it opens doors to accurate diagnoses of diseases and novel biomedical discovery. During the image collection, imaging devices are quite often interfered by various noise sources. Impulse noise degrades biomedical image details such as edges, contours and texture. In this paper we present a robust technique for filtering impulse-noise degraded biomedical images. The proposed filter is based on noise detector and cubic interpolation. Experimental results on several types of biomedical images and comparisons with several existing noise-filtering models have demonstrated that not only the proposed filter is effective for noise removal but also for image detail preservation.

  • 3165. Xu, Jinwei
    et al.
    Pham, Tuan D
    School of Computer Science and Engineering Research Center for Advanced Information Science and Technology The University of Aizu Aizu-Wakamatsu City, Fukushima, 965-8580, Japan.
    Robust impulse-noise filtering for biomedical images using numerical interpolation2012Inngår i: Image Analysis and Recognition / [ed] Campilho, Aurélio and Kamel, Mohamed, Berlin, Heidelberg: Springer Berlin/Heidelberg, 2012, s. 146-155Kapittel i bok, del av antologi (Annet vitenskapelig)
    Abstract [en]

    Analysis of molecular and medical images is an important area of interdisciplinary research. Accurate interpretation and understanding of those images is increasingly demanding because it opens doors to accurate diagnoses of diseases and novel biomedical discovery. During the image collection, imaging devices are quite often interfered by various noise sources. Impulse noise degrades biomedical image details such as edges, contours and texture. In this paper we present a robust technique for filtering impulse-noise degraded biomedical images. The proposed filter is based on noise detector and cubic interpolation. Experimental results on several types of biomedical images and comparisons with several existing noise-filtering models have demonstrated that not only the proposed filter is effective for noise removal but also for image detail preservation.

  • 3166.
    Y Banaem, Hossein
    et al.
    Tehran University of Medical Science, Iran.
    Ahmadian, Alireza
    Tehran University of Medical Science, Iran.
    Saberi, Hooshangh
    Tehran University of Medical Science, Iran.
    Daneshmehr, Alireza
    University of Tehran, Iran.
    Khodadad, Davood
    Tehran University of Medical Science, Iran.
    Brain tumor modeling: glioma growth and interaction with chemotherapy2011Inngår i: International Conference on Graphic and Image Processing (ICGIP 2011) / [ed] Yi Xie, Yanjun Zheng, 2011, artikkel-id 82851MKonferansepaper (Fagfellevurdert)
    Abstract [en]

    In last decade increasingly mathematical models of tumor growths have been studied, particularly on solid tumors which growth mainly caused by cellular proliferation. In this paper we propose a modified model to simulate the growth of gliomas in different stages. Glioma growth is modeled by a reaction-advection-diffusion. We begin with a model of untreated gliomas and continue with models of polyclonal glioma following chemotherapy. From relatively simple assumptions involving homogeneous brain tissue bounded by a few gross anatomical landmarks (ventricles and skull) the models have been expanded to include heterogeneous brain tissue with different motilities of glioma cells in grey and white matter. Tumor growth is characterized by a dangerous change in the control mechanisms, which normally maintain a balance between the rate of proliferation and the rate of apoptosis (controlled cell death). Result shows that this model closes to clinical finding and can simulate brain tumor behavior properly.

  • 3167.
    Yadav, Priti
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Mekanik. KTH, Skolan för teknikvetenskap (SCI), Centra, BioMEx.
    Shefelbine, Sandra J.
    Ponten, Eva
    Gutierrez-Farewik, Elena
    KTH, Skolan för teknikvetenskap (SCI), Mekanik. KTH, Skolan för teknikvetenskap (SCI), Centra, BioMEx. Department of Women’s and Children’s Health, Pediatric Orthopaedic Surgery Karolinska Institutet Stockholm Sweden.
    Influence of muscle groups' activation on proximal femoral growth tendency2017Inngår i: Biomechanics and Modeling in Mechanobiology, ISSN 1617-7959, E-ISSN 1617-7940, Vol. 16, nr 6, s. 1869-1883Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Muscle and joint contact force influence stresses at the proximal growth plate of the femur and thus bone growth, affecting the neck shaft angle (NSA) and femoral anteversion (FA). This study aims to illustrate how different muscle groups' activation during gait affects NSA and FA development in able-bodied children. Subject-specific femur models were developed for three able-bodied children (ages 6, 7, and 11 years) using magnetic resonance images. Contributions of different muscle groups-hip flexors, hip extensors, hip adductors, hip abductors, and knee extensors-to overall hip contact force were computed. Specific growth rate for the growth plate was computed, and the growth was simulated in the principal stress direction at each element in the growth front. The predicted growth indicated decreased NSA and FA (of about over a four-month period) for able-bodied children. Hip abductors contributed the most, and hip adductors, the least, to growth rate. All muscles groups contributed to a decrease in predicted NSA (similar to 0.01 degrees-0.04 degrees and FA (similar to 0.004 degrees-0.2 degrees), except hip extensors and hip adductors, which showed a tendency to increase the FA (similar to 0.004 degrees-0.2 degrees). Understanding influences of different muscle groups on long bone growth tendency can help in treatment planning for growing children with affected gait.

  • 3168. Yamazaki, Junya
    et al.
    Gilgien, Matthias
    Kleiven, Svein
    KTH, Skolan för teknik och hälsa (STH), Medicinsk teknik, Neuronik.
    McIntosh, Andrew S.
    Nachbauer, Werner
    Müller, Erich
    Bere, Tone
    Bahr, Roald
    Krosshaug, Tron
    Analysis of a Severe Head Injury in World Cup Alpine Skiing: A Case Report.2015Inngår i: Medicine & Science in Sports & Exercise, ISSN 0195-9131, E-ISSN 1530-0315, Vol. 47, nr 6, s. 1113-1118Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Traumatic brain injury (TBI) is the leading cause of death in alpine skiing. It has been found that helmet use can reduce the incidence of head injuries between 15% and 60%. However, knowledge on optimal helmet performance criteria in World Cup alpine skiing is currently limited owing to the lack of biomechanical data from real crash situations. Purpose: This study aimed to estimate impact velocities in a severe TBI case in World Cup alpine skiing. Methods: Video sequences from a TBI case in World Cup alpine skiing were analyzed using a model-based image matching technique. Video sequences from four camera views were obtained in full high-definition (1080p) format. A three-dimensional model of the course was built based on accurate measurements of piste landmarks and matched to the background video footage using the animation software Poser 4. A trunk-neck-head model was used for tracking the skier's trajectory. Results: Immediately before head impact, the downward velocity component was estimated to be 8 m.s(-1). After impact, the upward velocity was 3 m.s(-1), whereas the velocity parallel to the slope surface was reduced from 33 m.s(-1) to 22 m.s(-1). The frontal plane angular velocity of the head changed from 80 radIsj1 left tilt immediately before impact to 20 rad.s(-1) right tilt immediately after impact. Conclusions: A unique combination of high-definition video footage and accurate measurements of landmarks in the slope made possible a high-quality analysis of head impact velocity in a severe TBI case. The estimates can provide crucial information on how to prevent TBI through helmet performance criteria and design.

  • 3169.
    Yan, Hongji
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Polymerkemi.
    New insights into principles of scaffolds design for bone application2016Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    This thesis presents deeper insights into bone applicable biomaterials’ design. Poor affinity of BMP-2 towards scaffolds required supra-physiological dose administration. Though molecules containing sulfate could sustain BMP-2 release, side effects occurred due to BMP-2 supra-dose, or these sulfate-containing biomolecules.

    Improved affinity between BMP-2 and scaffolds was first witnessed by using an acidic carrier (paper I). Hyaluronic acid (HA) hydrazone derived hydrogels having a pH of 4.5-loaded BMP-2 showed sustained release of bioactive BMP-2 in vitro and enhanced bone formation in vivo, while pH 7 HA hydrogels showed Fickian behavior and less bone formation in vivo. Computational evaluation revealed stronger electrostatic interactions between BMP-2, and HA were predominant at pH 4.5, whereas, weaker Van der Waals interactions played a key role at pH 7.

    During the pre-bone formation phase, endogenous cell responses to pH 4.5 and 7 with or without BMP-2 were investigated. HA hydrogels exhibited extraordinary biocompatibility and recruitment of neutrophils, monocytes, macrophages and stromal cells regardless of hydrogels’ pH and BMP-2 presence.  The different inflammatory responses to HA hydrogels were observed (Appendix).

    Thiol derivatives can cleave the disulfide bond of BMP-2 to generate inactive monomeric BMP-2. In paper II, thiol-acrylate chemistry-based HA hydrogels (HA-SH) were compared to hydrazone-based HA hydrogels as BMP-2 carriers. Thiol modified HA disrupted BMP-2 integrity and bioactivity. HA-SH hydrogels with BMP-2 exhibited less bioactive BMP-2 release in vitro and induced less bone formation in vivo.

    Accumulated evidence has shown great osteogenic potential of lithium ions (Li). In paper III, we coordinated Li onto HA-PVA hydrazone hydrogels (Li-gel); Li-gel enhanced 3D cultured hMSCs osteogenic differentiation and induced higher bone formation in CAM defect model.

    Instead of BMP-2 protein, delivery of BMP-2-coding-plasmid can produce BMP-2 over a long term at a closer physiological level. Yet, efficient gene delivery reagents are needed. In paper IV, two novel gene delivery nanoplexes were developed by post coating DNA-nanoplexes with chondroitin sulfate (CS). To ensure the stability, aldehyde-modified CS (CS-CHO) reacted with free amines of pDNA/PEI complexes. We provided first evidence that CS-CHO coated nanoplexes controlled the release from endosomes, which is essential for higher transfection efficiency.

  • 3170.
    Yan, Hongji
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström.
    Hulsart-Billström, Gry
    Rekha, Tripathi
    Stefanie, Inglis
    Wang, Shujiang
    Stoddart, Martin J.
    Oreffo, Richard
    Hilborn, Jöns
    Varghese, Oommen P.
    Lithium hyaluronate hydrogels enhance osteogenesis in vitro and ex vivoManuskript (preprint) (Annet (populærvitenskap, debatt, mm))
    Abstract [en]

    Lithium is a clinical drug for bipolar disorders and can enhance bone mass, promote osteogenesis of MSCs through inhibiting the Wnt/β-catenin signalling inhibitor GSK 3β. However, the systemic administration of lithium can trigger severe side-effects. Local administration has been attempted in the treatment of bone defects in animal models with positive outcomes. In this study, we explored a pre-manufactured hydrogel system containing the Li ion (Li-gel) in bone applications. Human MSCs cultured in this Li-gel exhibited enhanced osteogenic differentiation. Furthermore, this Li-gel was used to treat chick embryo chorioallantoic membrane (CAM) femur defects and enhanced the bone healing process. 

  • 3171.
    Yan, Hongji
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Polymerkemi.
    Paidikondala, Maruthibabu
    Hulsart-Billström, Gry
    Larsson, Sune
    Hilborn, Jöns
    Varghese, Oommen P.
    The choice of crosslinking chemistry for hydrogel development influences BMP-2 stability and bioactivity in vivoManuskript (preprint) (Annet (populærvitenskap, debatt, mm))
    Abstract [en]

    Site-specific administration of bone morphogenetic protein-2 (BMP-2) at the site of a bone fracture via scaffolds can minimise systemic side-effects and exhibit sustained biological effects. While this method requires sufficient scaffolds to preserve the BMP-2 structure and tuned release patterns, the incorporation of thiol-acrylate chemistry has shown great success in scaffold synthesis. However, thiolates attack the sulphur atoms of disulphide bonds, displacing the other sulphur atom and forming a new disulphide bond, hence at physiological conditions, thiol-modified scaffold components could potentially attack inter-chain disulphide bonds of BMP-2 by thiol-exchange reactions. This therefore led us to compare hyaluronic acid (HA) hydrogels synthesised via thiol-acrylate (HA-S) and hydrazone crosslinking chemistry (HA-H) formed BMP-2 carriers. The study revealed the integrity of BMP-2 dimer structures can be disrupted and reveals the osteogenic capacity of BMP-2 by HA derivatives (HA-SH). BMP-2 bioactivity released from HA-S hydrogels are decreased when compared to HA-H hydrogels. This was further confirmed via the rat ectopic bone model, showing that bone volume was significantly higher when induced by HA-H hydrogels with BMP-2 than compared to HA-S hydrogel with BMP-2. This study gives new insights into scaffolds synthesis, showing that biomolecule bioactivity needs to be considered when choosing a chemistry for scaffolds synthesis. 

  • 3172.
    Yan, Hongji
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Polymerkemi.
    Tommaso, Casalini
    Hulsart-Billström, Gry
    Wang, Shujiang
    Salvalaglio, Matteo
    Larsson, Sune
    Hilborn, Jöns
    Varghese, Oommen P.
    Tuning biomaterial pH for regulating BMP-2 stability and bioactivity in vitro and in vivoManuskript (preprint) (Annet (populærvitenskap, debatt, mm))
    Abstract [en]

    The poor affinity of rhBMP-2 to the scaffolds leads to high dose administration requirement resulted in massive side effects has been the hurdle for successful clinic translation for treating delayed unions or remained non-union at bone defect. Optimizing the scaffolds with the purpose of obtaining optimal BMP2 dose and release have been addressed as critical for BMP-2 administration, however, the results are contradictory concerning whether bone formation is more beneficial from burst or controlled release of BMP2. While this might be due to these studies incorporated other bioactive molecules onto scaffolds to immobilize BMP-2.  In this study, we report the affinities of rhBMP-2 to the scaffolds can be improved by only tuning the pH of hyaluronic acid (HA) hydrazone crosslinking hydrogel without addition of other molecules. Neo bone induced by BMP-2 showed significantly higher volume with more impact structure and vascularization in pH 4.5 HA hydrogel compared to that in pH7 HA hydrogel. The mechanisms were demonstrated by In vitro BMP-2 release followed by diffusion quantitative calculation and computational simulation methods. Initial burst release of BMP-2 from pH 7 HA hydrogels with the fitting of Fickian behavior while sustained release from pH 4.5 HA hydrogel was observed. Computational stimulation revealed this is due to the protonation state of BMP2 at pH 4.5 resulted in stronger electrostatic interaction with negatively charged groups along the backbone of hyaluronic acid molecules compared to at pH 7. This study gives new direction to scaffolds designing for basic bioactive protein applications in future.  

  • 3173.
    Yang, Geng
    et al.
    Zhejiang Univ, Coll Mech Engn, State Key Lab Fluid Power & Mechatron Syst, Hangzhou 310058, Zhejiang, Peoples R China..
    Jiang, Mingzhe
    Univ Turku, Dept Future Technol, SF-20500 Turku, Finland..
    Ouyang, Wei
    Inst Pasteur, Imaging & Modeling Unit, F-75015 Paris, France..
    Ji, Guangchao
    KTH, Skolan för teknik och hälsa (STH).
    Xie, Haibo
    Zhejiang Univ, Coll Mech Engn, State Key Lab Fluid Power & Mechatron Syst, Hangzhou 310058, Zhejiang, Peoples R China..
    Rahmani, Amir M.
    Univ Calif Irvine, Dept Comp Sci, Irvine, CA 92697 USA.;TU Wien, Inst Comp Technol, A-1040 Vienna, Austria..
    Liljeberg, Pasi
    Univ Turku, Dept Future Technol, SF-20500 Turku, Finland..
    Tenhunen, Hannu
    KTH, Skolan för teknik och hälsa (STH). Univ Turku, Dept Future Technol, SF-20500 Turku, Finland..
    IoT-Based Remote Pain Monitoring System: From Device to Cloud Platform2018Inngår i: IEEE journal of biomedical and health informatics, ISSN 2168-2194, E-ISSN 2168-2208, Vol. 22, nr 6, s. 1711-1719Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Facial expressions are among behavioral signs of pain that can be employed as an entry point to develop an automatic human pain assessment tool. Such a tool can be an alternative to the self-report method and particularly serve patients who are unable to self-report like patients in the intensive care unit and minors. In this paper, a wearable device with a biosensing facial mask is proposed to monitor pain intensity of a patient by utilizing facial surface electromyogram (sEMG). The wearable device works as a wireless sensor node and is integrated into an Internet of Things (IoT) system for remote pain monitoring. In the sensor node, up to eight channels of sEMG can be each sampled at 1000 Hz, to cover its full frequency range, and transmitted to the cloud server via the gateway in real time. In addition, both low energy consumption and wearing comfort are considered throughout the wearable device design for long-term monitoring. To remotely illustrate real-time pain data to caregivers, a mobile web application is developed for real-time streaming of high-volume sEMG data, digital signal processing, interpreting, and visualization. The cloud platform in the system acts as a bridge between the sensor node and web browser, managing wireless communication between the server and the web application. In summary, this study proposes a scalable IoT system for real-time biopotential monitoring and a wearable solution for automatic pain assessment via facial expressions.

  • 3174. Yang, Geng
    et al.
    Li, Xie
    Mäntysalo, Matti
    Zhou, Xiaolin
    Pang, Zhibo
    Xu, Li Da
    Kao-Walter, Sharon
    Blekinge Tekniska Högskola, Sektionen för ingenjörsvetenskap, Avdelningen för maskinteknik.
    Chen, Qiang
    Zheng, Lirong
    A Health-IoT Platform Based on the Integration of Intelligent Packaging, Unobtrusive Bio-Sensor and Intelligent Medicine Box2014Inngår i: IEEE Transactions on Industrial Informatics, ISSN 1551-3203, E-ISSN 1941-0050, Vol. 10, nr 4, s. 2180-2191Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In-home healthcare services based on the Internet-of-Things (IoT) have great business potential; however, a comprehensive platform is still missing. In this paper, an intelligent home-based platform, the iHome Health-IoT, is proposed and implemented. In particular, the platform involves 1) an open-platform-based intelligent medicine box (iMedBox) with enhanced connectivity and interchangeability for the integration of devices and services, 2) intelligent pharmaceutical packaging (iMedPack) with communication capability enabled by passive radio-frequency identification (RFID) and actuation capability enabled by functional materials, and 3) flexible and wearable bio-medical sensor device (Bio-Patch) enabled by the state-of-the-art inkjet printing technology and system-on-chip. The proposed platform seamlessly fuses IoT devices (e.g., wearable sensors, intelligent medicine packages, etc.) with in-home healthcare services (e.g., telemedicine) for an improved user experience and service efficiency. The feasibility of the implemented iHome Health-IoT platform has been proven in field trials.

  • 3175.
    Yang, Geng
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Elektroniksystem. KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, VinnExcellence Center for Intelligence in Paper and Packaging, iPACK.
    Xie, Li
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Elektroniksystem. KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, VinnExcellence Center for Intelligence in Paper and Packaging, iPACK.
    Mäntysalo, Matti
    Department of Electronics, Tampere University of Technology.
    Chen, Jian
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Elektroniksystem. KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, VinnExcellence Center for Intelligence in Paper and Packaging, iPACK.
    Tenhunen, Hannu
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Elektroniksystem. KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, VinnExcellence Center for Intelligence in Paper and Packaging, iPACK.
    Zheng, Li-Rong
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Elektroniksystem. KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, VinnExcellence Center for Intelligence in Paper and Packaging, iPACK.
    Bio-Patch Design and Implementation Based on a Low-Power System-on-Chip and Paper-Based Inkjet Printing Technology2012Inngår i: IEEE transactions on information technology in biomedicine, ISSN 1089-7771, E-ISSN 1558-0032, Vol. 16, nr 6, s. 1043-1050Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This paper presents the prototype implementation of a Bio-Patch using fully integrated low-power System-on-Chip (SoC) sensor and paper-based inkjet printing technology. The SoC sensor is featured with programmable gain and bandwidth to accommodate a variety of bio-signals. It is fabricated in a 0.18-µm standard CMOS technology, with a total power consumption of 20 µW from a 1.2 V supply. Both the electrodes and interconnections are implemented by printing conductive nano-particle inks on a flexible photo paper substrate using inkjet printing technology. A Bio-Patch prototype is developed by integrating the SoC sensor, a soft battery, printed electrodes and interconnections on a photo paper substrate. The Bio-Patch can work alone or operate along with other patches to establish a wired network for synchronous multiple-channel bio-signals recording. The measurement results show that electrocardiogram and electromyogram are successfully measured in in-vivo tests using the implemented Bio-Patch prototype.

  • 3176.
    Yang, Liyun
    KTH, Skolan för teknik och hälsa (STH).
    Development and validation of a novel iOS application for measuring arm inclination2015Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Work in demanding postures is a known risk factor for work-related musculoskeletal disorders (MSDs), specifically work with elevated arms may cause neck/shoulder disorders. Such a disorder is a tragedy for the individual, and costly for society. Technical measurements are more precise in estimating the work exposure, than observation and self-reports, and there is a need for uncomplicated methods for risk assessments. The aim of this project was to develop and validate an iOS application for measuring arm elevation angle.

    Such an application was developed, based on the built-in accelerometer and gyroscope of the iPhone/iPod Touch. The application was designed to be self-exploratory. Directly after a measurement, 10th, 50th and 90th percentiles of angular distribution and median angular velocity, and percentage of time above 30°, 60°, and 90° are presented. The focused user group, ergonomists, was consulted during the user interface design phase. Complete angular datasets may be exported via email as text files for further analyses.

    The application was validated by comparison to the output of an optical motion capture system for four subjects. The two methods correlated above 0.99, with absolute error below 4.8° in arm flexion and abduction positions. During arm swing movements, the average root-mean-square differences (RMSDs) were 3.7°, 4.6° and 6.5° for slow (0.1 Hz), medium (0.4 Hz) and fast (0.8 Hz) arm swings, respectively. For simulated painting, the mean RMSDs was 5.5°.

    Since the accuracy was similar to other tested field research methods, this convenient and “low-cost” application should be useful for ergonomists, for risk assessments or educational use. The plan is to publish this iOS application on Apple Store (Apple Inc.) for free. New user feedback may further improve the user interface.

  • 3177.
    Yang, Liyun
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Medicinteknik och hälsosystem, Ergonomi. Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden.
    Borgström, D.
    Forsman, Mikael
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Medicinteknik och hälsosystem, Ergonomi. Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden.
    Validation and comparison of three positioning protocols of inertial measurement units for measuring trunk movement2019Inngår i: 20th Congress of the International Ergonomics Association, IEA 2018, Springer, 2019, s. 205-211Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Postures and movements of the trunk are of ergonomic concern when evaluating the risks at work. Technical measurement methods can be used for measurements of trunk movements for long duration with high accuracy, and are therefore increasingly used in practice and research. However, currently there is no standardized protocol for the sensor placement for trunk measurement. Three placement protocols of inertial measurement units (IMUs), including placement on C7, T4 and sternum (St), in combination with S1 spinous process, were compared with an optical motion capture (OMC) system. Four subjects performed a movement test including forward to backward bending, sideward bending and twisting of the trunk, and a symmetrical lifting task. Root-mean-square differences (RMSDs) and Pearson’s correlation were calculated between the two systems. For the movement tests, the RMSDs of the forward inclination at the 10th, 50th and 90th percentiles from the three IMUs were all smaller than 7.3°. Larger differences were shown for C7 of the sideward inclination at 90th percentile (10.8°). Also for the twisting, larger differences were shown, especially for C7-S1 and T4-S1 (RMSD = 16.5° and 19.8°). For the lifting tests of forward inclination, St had the smallest differences compared to OMC (RMSDs &lt; 4.1°), while slightly larger errors were found for C7 and T4 at the 90th percentile (RMSDs = 8.1° and 8.2°). Different positioning protocols seem to have a slightly different effect on the measurement accuracy of trunk movement. Considerations should be taken when comparing results across studies applying different protocols.

  • 3178.
    Yang, Liyun
    et al.
    KTH, Skolan för teknik och hälsa (STH), Hälso- och systemvetenskap, Ergonomi.
    Grooten, W. J. A.
    Forsman, M.
    An iPhone application for upper arm posture and movement measurements2017Inngår i: Applied Ergonomics, ISSN 0003-6870, E-ISSN 1872-9126, Vol. 65, s. 492-500Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    There is a need for objective methods for upper arm elevation measurements for accurate and convenient risk assessments. The aims of this study were (i) to compare a newly developed iOS application (iOS) for measuring upper arm elevation and angular velocity with a reference optical tracking system (OTS), and (ii) to compare the accuracy of the iOS incorporating a gyroscope and an accelerometer with using only an accelerometer, which is standard for inclinometry. The iOS-OTS limits of agreement for static postures (9 subjects) were -4.6° and 4.8°. All root mean square differences in arm swings and two simulated work tasks were <6.0°, and all mean correlation coefficients were >0.98. The mean absolute iOS-OTS difference of median angular velocity was <13.1°/s, which was significantly lower than only using an accelerometer (<43.5°/s). The accuracy of this iOS application compares well to that of today's research methods and it can be useful for practical upper arm measurements.

  • 3179.
    Yang, Liyun
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Medicinteknik och hälsosystem, Ergonomi.
    Lu, Ke
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH).
    Forsman, Mikael
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Medicinteknik och hälsosystem, Ergonomi.
    Lindecrantz, Kaj
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Industriell bioteknologi.
    Seoane, Fernando
    Ekblom, Örjan
    Eklund, Jörgen
    Development of smart wearable systems for physiological workload assessment using heart rate and accelerometryManuskript (preprint) (Annet vitenskapelig)
  • 3180.
    Yang, Zhen
    KTH, Skolan för teknik och hälsa (STH).
    Ståställningens påverkan på lederna i de nedre extremiteterna: en pilotstudie2013Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [sv]

    Barn med en allvarlig cerebral pares (CP) diagnos har begränsad eller obefintlig förmåga att stå självständigt. Tillståndet medför även en stor risk för subluxation i höftlederna. En befintlig teori bland ortopeder och sjukgymnaster idag är att hjälpmedel för ståträning för barn med CP, såsom ståskal, med höfter i ett abducerade läge kan motverka höftledernas negativa utveckling. Hittills saknas det dock vetenskapliga bevis för denna teori.

    TeamOlmed Barn & Ungdom tillverkar ståskal med 30 graders abduktionsvinkel enligt teorin ovan. Men kunskaperna inom området är begränsade och företaget önskade undersöka om hypotesen stämmer och hur de biomekaniska förutsättningarna påverkas av ståskalen.

    Detta examensarbete fokuserar på olika ståställningar i abduktion för en frisk person och dess inverkan i de nedre extremiteterna i syfte att undersöka den befintliga teorin. Rörelseanalyssystemet Vicon Nexus användes för datainsamling och analys av moment kring knälederna. Vid analys av krafterna i höftlederna användes OpenSim, ett simuleringsprogram för det muskuloskeletala systemet i 3D.

    Resultatet från Vicon visar att knäna har ett inre varusmoment i frontalplanet, vilket är ofarligt för knälederna, i såväl abducerade som vanlig höftposition. Simuleringsresultatet från OpenSim visar att kraftvektorernas riktningar ändras i samband med ändringar av abduktionsvinklar. Detta betyder att kraftvektorernas riktningar i höfterna, uttryckta i femurs koordinatsystem, är snarlika för ståpositioner med olika abduktionsvinklar. Beloppet av kontaktkraften ökade dock med ökande höftabduktionsvinkel.

    Momenten som uppstår vid olika ståställningar är ofarliga för knälederna och kraftvektorernas riktningar i höfterna är oberoende av abduktionsvinklarna för en frisk person. Den enda skillnaden i höftbelastning med stående i höftabduktion var ökade belopp av höftkontaktkrafter. För att noggrannt kunna utvärdera huruvida en ökad kontaktkraft kan påverka höftens tendens att migrera ur led, samt huruvida liknande observationer finns hos patienter med CP skador i sina ståskal, krävs det vidare studier. Tack vare observationerna av denna pilotstudie kan man ställa mer relevanta studiefrågor kring biomekaniska mekanismer i en större studie med barn med CP-diagnoser.

  • 3181.
    Yanlun, Zhu
    et al.
    Shanghai Jiao Tong University.
    Lingzhi, Kong
    Shanghai Jiao Tong University.
    Fatemeh, Farhadi
    Shanghai Jiao Tong University.
    Xia, Wei
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Chang, Jiang
    Shanghai Institute of ceramics, Chinese academy of sciences.
    Yaohua, He
    Shanghai Jiao Tong University.
    Haiyan, Li
    Shanghai Jiao Tong University.
    An injectable continuous stratified structurally and functionally biomimetic construct for enhancing osteochondral regeneration2018Inngår i: Biomaterials, ISSN 0142-9612, E-ISSN 1878-5905, Vol. 192, s. 149-158Artikkel i tidsskrift (Fagfellevurdert)
  • 3182.
    Yavari, Nazila
    et al.
    Department of Physics, Lund Institute of Technology, Lund, Sweden.
    Dam, J. S.
    National Laser Centre, CSIR, Pretoria, South Africa.
    Antonsson, Johan
    Linköpings universitet, Institutionen för medicinsk teknik, Biomedicinsk instrumentteknik. Linköpings universitet, Tekniska högskolan.
    Wårdell, Karin
    Linköpings universitet, Institutionen för medicinsk teknik, Biomedicinsk instrumentteknik. Linköpings universitet, Tekniska högskolan.
    Anderson-Engels, Stefan
    Department of Physics, Lund Institute of Technology, Lund, Sweden.
    In vitro measurements of optical properties of porcine brain using a novel compact device2005Inngår i: Medical and Biological Engineering and Computing, ISSN 0140-0118, E-ISSN 1741-0444, Vol. 43, nr 5, s. 658-666Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Knowledge of the optical properties of tissues can be applied in numerous medical and scientific fields, including cancer diagnostics and therapy. There are many different ways of determining the optical properties of turbid media. The paper describes measurements of the optical properties of porcine brain tissue using novel instrumentation for simultaneous absorption and scattering characterisation of small turbid samples. Integrating sphere measurements are widely used as a reference method for determination of the optical properties of relatively thin turbid samples. However, this technique is associated with bulky equipment, complicated measuring techniques, interference compensation techniques and inconvenient sample handling. It is believed that the sphere for some applications can be replaced by a new, compact device, called the combined angular and spatially resolved head sensor, to measure the optical properties of thin turbid samples. The results compare very well with data obtained with an integrating sphere for well-defined samples. The instrument was shown to be accurate to within 12% for μa and 1% for μ s in measurements of intralipid-ink samples. The corresponding variations of data were 17% and 2%, respectively. The reduced scattering coefficient for porcine white matter was measured to be 100 cm−1 at 633 nm, and the value for coagulated brain tissue was 65 cm−1. The corresponding absorption coefficients were 2 and 3 cm−1, respectively.

  • 3183.
    Ye, Luming
    KTH, Skolan för teknik och hälsa (STH), Medicinsk teknik.
    Perception Metrics in Medical Imaging2012Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
  • 3184.
    Ynnerman, Anders
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska fakulteten. Linköpings universitet, Centrum för medicinsk bildvetenskap och visualisering, CMIV.
    Rydell, Thomas
    Persson, Anders
    Linköpings universitet, Institutionen för medicin och hälsa, Avdelningen för radiologiska vetenskaper. Linköpings universitet, Medicinska fakulteten. Linköpings universitet, Centrum för medicinsk bildvetenskap och visualisering, CMIV. Östergötlands Läns Landsting, Diagnostikcentrum, Röntgenkliniken i Linköping.
    Ernvik, Aron
    Forsell, Camilla
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska fakulteten.
    Ljung, Patric
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska fakulteten.
    Lundström, Claes
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska fakulteten. Linköpings universitet, Centrum för medicinsk bildvetenskap och visualisering, CMIV.
    Multi-Touch Table System for Medical Visualization2015Inngår i: Eurographics 2015: Dirk Bartz Prize, Eurographics - European Association for Computer Graphics, 2015Konferansepaper (Annet vitenskapelig)
    Abstract [en]

    Medical imaging plays a central role in a vast range of healthcare practices. While the usefulness of 3D visualizations is well known, the adoption of such technology has previously been limited in many medical areas. This paper, awarded the Dirk Bartz Prize for Visual Computing in Medicine 2015, describes the development of a medical multi-touch visualization table that successfully has reached its aim to bring 3D visualization to a wider clinical audience. The descriptions summarize the targeted clinical scenarios, the key characteristics of the system, and the user feedback obtained.

  • 3185. Yong, Y.S.
    et al.
    Aravazhi, S.
    Vázquez-Córdova, S.A.
    García-Blanco, S.M.
    Pollnau, Markus
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik. Integrated Optical MicroSystems Group, MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, Enschede, Netherlands.
    Highly Yb-doped KGd(WO4)2 thin-film amplifier2015Inngår i: CLEO: Science and Innovations 2015, Optical Society of America, 2015Konferansepaper (Fagfellevurdert)
    Abstract [en]

    We report record-high small-signal gain of 1050 dB/cm at 981 nm wavelength in a KGd<inf>0.425</inf>Yb<inf>0.575</inf>(WO<inf>4</inf>)<inf>2</inf> thin film. The sensitivity of gain to the shift of beam-focus position, which is critical under non-waveguiding conditions, is investigated.

  • 3186. Yousafzai, Muhammad Sulaiman
    et al.
    Coceano, Giovanna
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik.
    Bonin, Serena
    Niemela, Joseph
    Scoles, Giacinto
    Cojoc, Dan
    Investigating the effect of cell substrate on cancer cell stiffness by optical tweezers2017Inngår i: Journal of Biomechanics, ISSN 0021-9290, E-ISSN 1873-2380, Vol. 60, s. 266-269Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The mechanical properties of cells are influenced by their microenvironment. Here we report cell stiffness alteration by changing the cell substrate stiffness for isolated cells and cells in contact with other cells. Polydimethylsiloxane (PDMS) is used to prepare soft substrates with three different stiffness values (173, 88 and 17 kPa respectively). Breast cancer cells lines, namely HBL-100, MCF-7 and MDA-MB-231 with different level of aggressiveness are cultured on these substrates and their local elasticity is investigated by vertical indentation of the cell membrane. Our preliminary results show an unforeseen behavior of the MDA-MB-231 cells. When cultured on glass substrate as isolated cells, they are less stiff than the other two types of cells, in agreement with the general statement that more aggressive and metastatic cells are softer. However, when connected to other cells the stiffness of MDA-MB-231 cells becomes similar to the other two cell lines. Moreover, the stiffness of MDA-MB-231 cells cultured on soft PDMS substrates is significantly higher than the stiffness of the other cell types, demonstrating thus the strong influence of the environmental conditions on the mechanical properties of the cells. 

  • 3187.
    Yousefi, Hossein
    et al.
    Tehran University of Medical Sciences (TUMS), Iran.
    Ahmadian, Alireza
    Tehran University of Medical Sciences (TUMS), Iran.
    Khodadad, Davood
    Luleå University of Technology ; Exceptional Talents Development Centre, Iran.
    Saberi, Hooshangh
    Tehran University of Medical Sciences (TUMS), Iran ; Spinal Injuries Repair Research Centre, Iran.
    Daneshmehr, Alireza
    University of Tehran, Iran.
    An Optimised Linear Mechanical Model for Estimating Brain Shift Caused by Meningioma Tumours2013Inngår i: International Journal of Biomedical Science and Engineering, ISSN 2376-7227, Vol. 1, nr 1, s. 1-9Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Estimation of brain deformation plays an important role in computer-aided therapy and image-guided neurosurgery systems. Tumour growth can cause brain deformation and change stress distribution in the brain. Biomechanical models exist that use a finite element method to estimate brain shift caused by tumour growth. Such models can be categorised as linear and non-linear models, both of which assume finite deformation of the brain after tumour growth. Linear models are easy to implement and fast enough to for applications such as IGS where the time is a great of concern. However their accuracy highly dependent on the parameters of the models in this paper, we proposed an optimisation approach to improve a naive linear model to achieve more precise estimation of brain displacements caused by tumour growth. The optimisation process has improved the accuracy of the model by adapting the brain model parameters according to different tomour sizes.We used patient-based tetrahedron finite element mesh with proper material properties for brain tissue and appropriate boundary conditions in the tumour region. Anatomical landmarks were determined by an expert and were divided into two different sets for evaluation and optimisation. Tetrahedral finite element meshes were used and the model parameters were optimised by minimising the mean square distance between the predicted locations of the anatomical landmarks derived from Brain Atlas images and their actual locations on the tumour images. Our results demonstrate great improvement in the accuracy of an optimised linear mechanical model that achieved an accuracy rate of approximately 92%.

  • 3188.
    Yousefi-Banaem, Hossein
    et al.
    Isfahan University of Med. Sci., Iran.
    Kermani, Saeed
    Isfahan University of Med. Sci., Iran.
    Sarrafzadeh, Omid
    Isfahan University of Med. Sci., Iran.
    Khodadad, Davood
    Luleå University of Technology.
    An improved spatial FCM algorithm for cardiac image segmentation2013Inngår i: 13th Iranian Conference on Fuzzy Systems (IFSC), 2013, IEEE Press, 2013Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Image segmentation is one of challenging field in medical image processing. Segmentation of cardiac wall is one of challenging work and it is very important step in evaluation of heart functionality by existing methods. For cardiac image analysis, Fuzzy C- Means (FCM) algorithm proved to be superior over the other clustering approaches in segmentation field. However, the nave FCM algorithm is sensitive to noise because of not considering the spatial information in the image. In this paper an improved FCM algorithm is formulated by incorporating the spatial domain neighborhood information into the membership function for clustering (ISFCM). In this paper we applied improved Fuzzy c-Means with spatial information for left ventricular wall segmentation. Obtained results showed that the proposed method can segment cardiac wall automatically with acceptable accuracy. The comparison of proposed method with nave FCM proved that ISFCM can segment with more accuracy than nave FCM.

  • 3189.
    Ytreberg, Erik
    et al.
    Chalmers University of Technology, Sweden.
    Lagerström, Maria
    Chalmers University of Technology, Sweden; Stockholm University, Sweden.
    Holmqvist, Albin
    RISE - Research Institutes of Sweden, Biovetenskap och material, Kemi, material och ytor.
    Eklund, Brita
    Stockholm University, Sweden.
    Elwing, Hans
    University of Gothenburg, Sweden.
    Dahlström, Magnus
    RISE - Research Institutes of Sweden, Biovetenskap och material, Kemi, material och ytor.
    Dahl, Peter
    University of Gothenburg, Sweden.
    Dahlström, Mia
    RISE - Research Institutes of Sweden, Biovetenskap och material, Kemi, material och ytor.
    A novel XRF method to measure environmental release of copper and zinc from antifouling paints2017Inngår i: Environmental Pollution, ISSN 0269-7491, E-ISSN 1873-6424, Vol. 225, s. 490-496Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The release of copper (Cu) and zinc (Zn) from vessels and leisure crafts coated with antifouling paints can pose a threat to water quality in semi-enclosed areas such as harbors and marinas as well as to coastal archipelagos. However, no reliable, practical and low-cost method exists to measure the direct release of metals from antifouling paints. Therefore, the paint industry and regulatory authorities are obliged to use release rate measurements derived from either mathematical models or from laboratory studies. To bridge this gap, we have developed a novel method using a handheld X-Ray Fluorescence spectrometer (XRF) to determine the cumulative release of Cu and Zn from antifouling paints. The results showed a strong linear relationship between XRF Kα net intensities and metal concentrations, as determined by ICP-MS. The release of Cu and Zn were determined for coated panels exposed in harbors located in the Baltic Sea and in Kattegat. The field study showed salinity to have a strong impact on the release of Cu, i.e. the release increased with salinity. Contrary, the effect of salinity on Zn was not as evident. As exemplified in this work, the XRF method also makes it possible to identify the governing parameters to the release of Cu and Zn, e.g. salinity and type of paint formulation. Thus, the XRF method can be used to measure environmentally relevant releases of metallic compounds to design more efficient and optimized antifouling coatings.

  • 3190.
    Yu, Donggang
    et al.
    Bioinformatics Applications Research Centre, James Cook University Townsville, Australia.
    Pham, Tuan D
    Bioinformatics Applications Research Centre, James Cook University Townsville, Australia.
    Zhou, Xiaobo
    HCNR Centre for Bioinformatics Harvard Medical School, Boston, USA.
    Detection and Analysis of Cell Nuclear Phases2008Inngår i: Knowledge-Based Intelligent Information and Engineering Systems: 12th International Conference, KES 2008, Zagreb, Croatia, September 3-5, 2008, Proceedings, Part I / [ed] Ignac Lovrek, Robert J. Howlett and Lakhmi C. Jain, Springer Berlin/Heidelberg, 2008, s. 401-408Kapittel i bok, del av antologi (Fagfellevurdert)
    Abstract [en]

    Automated analysis of molecular images has increasingly become an important research in computational life science. In this paper some new and efficient algorithms for detecting and analyzing cell phases of high-content screening are presented. The conceptual frameworks are based on the morphological features of cell nuclei. Furthermore, the novel detecting and analyzing strategies of feed-forward and feed-back of cell phases are proposed based on grey feature, cell shape, geometrical features and difference information of corresponding neighbor frames. Experiment results tested the efficiency of the new method.

  • 3191.
    Yu, Donggang
    et al.
    School of Design, Communication and Information Technology, The University of Newcastle, Callaghan, NSW 2308, Australia.
    Pham, Tuan D
    School of Information Technology and Electrical Engineering, ADFA, The University of New South Wales, Canberra, ACT 2600, Australia.
    Zhou, Xiaobo
    HCNR Centre for Bioinformatics, Harvard Medical School, Boston, MA 02215, USA.
    Wong, Stephen TC
    HCNR Centre for Bioinformatics, Harvard Medical School, Boston, MA 02215, USA.
    Recognition and analysis of cell nuclear phases for high-content screening based on morphological features2009Inngår i: NOVA. The University of Newcastle’s Digital Repository, ISSN 0031-3203, Vol. 42, nr 4, s. 498-508Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Automated analysis of molecular images has increasingly become an important research in computational life science. In this paper some new and efficient algorithms for recognizing and analyzing cell phases of high-content screening are presented. The conceptual frameworks are based on the morphological features of cell nuclei. The useful preprocessing includes: smooth following and linearization; extraction of morphological structural points; shape recognition based morphological structure; issue of touching cells for cell separation and reconstruction. Furthermore, the novel detecting and analyzing strategies of feed-forward and feed-back of cell phases are proposed based on gray feature, cell shape, geometrical features and difference information of corresponding neighbor frames. Experiment results tested the efficiency of the new method.

  • 3192.
    Yu, Jun
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för matematik och matematisk statistik.
    Spatiotemporal modelling in MRI measurements for cancer therapy assessment2016Konferansepaper (Fagfellevurdert)
  • 3193.
    Yu, Jun
    et al.
    Biostokastikum, SLU.
    Östlund, Nils
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Centrum för medicinsk teknik och fysik (CMTF). Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Radiofysik.
    Löthgren, Pia
    Biostokastikum, SLU.
    Wavelet based noise reduction and parameter estimation in magnetic resonance signals2010Konferansepaper (Fagfellevurdert)
  • 3194.
    Yu, Sicong
    et al.
    KTH, Skolan för teknik och hälsa (STH), Hälso- och systemvetenskap.
    Hamid Muhammed, Hamed
    KTH, Skolan för teknik och hälsa (STH), Hälso- och systemvetenskap.
    Comparison of Pre- and Post-Reconstruction Denoising Approaches in Positron Emission Tomography2016Inngår i: THE 1ST 2016 INTERNATIONAL CONFERENCE ON BIOMEDICAL ENGINEERING (IBIOMED 2016), IEEE, 2016, s. 63-68Konferansepaper (Fagfellevurdert)
    Abstract [en]

    In Positron Emission Tomography (PET), image quality is highly degraded by noise. Therefore, two main PETimage denoising approaches can be used: pre- and postreconstruction denoising. In the pre-reconstruction approach the PET sinogram is denoised before forwarding it to the image reconstruction algorithm. On the other hand, the reconstructed PET-image is denoised in the post-reconstruction approach. In this study, comparison of image quality of the resulting images of the pre- and post-reconstruction approaches is performed. In both types of approaches, the Gaussian filter, the Non-Local Means filter (NLM), the Block-Matching and 3D filter (BM3D), the K-Nearest Neighbors Filter (KNN) and the Patch Confidence K-Nearest Neighbors Filter (PCkNN) are utilized. These approaches are evaluated on a simulated PET-phantom dataset, a real-life physical thorax-phantom PET dataset as well as a reallife MicroPET-scan dataset of a mouse. The performance is measured using the Signal-to-Noise Ratio (SNR) in addition to the Contrast-to-Noise Ratio (CNR) in the resulting images.

  • 3195.
    Yu, Sicong
    et al.
    KTH, Skolan för teknik och hälsa (STH), Hälso- och systemvetenskap, Systemsäkerhet och organisation.
    Hamid Muhammed, Hamed
    KTH, Skolan för teknik och hälsa (STH), Hälso- och systemvetenskap.
    Noise Type Evaluation in Positron Emission Tomography Images2016Inngår i: THE 1ST 2016 INTERNATIONAL CONFERENCE ON BIOMEDICAL ENGINEERING (IBIOMED 2016), IEEE, 2016, s. 101-106Konferansepaper (Fagfellevurdert)
    Abstract [en]

    In Positron Emission Tomography (PET), the coincident emission of gamma photon pairs constitutes the useful signals that should be detected and processed to reconstruct the desired PET images of the studied objects. However, along with the useful signal, noise is also generated and added to the detected signals that are sorted with respect to their line-ofresponse and arranged as a sinogram for each two-dimensional slice. In this paper, the type and properties of noise in PET sinogram data will be evaluated. Furthermore, the effect of the used linear and non-linear image denoising and reconstruction procedures on the type of noise will be analyzed. For this purpose, the Gaussian filter, the Median filter, the Patch Confidence k-Nearest Neighbor filter (PCkNN) and the Block Matching 3D filter (BM3D) were used to denoise PET image data, as well as the maximum likelihood expectation maximization algorithm (MLEM) and the Filtered Back Projection algorithm (FBP) to reconstruct the PET images.

  • 3196.
    Yuan, Qiantailang
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH).
    The Performance of the Depth Camera in Capturing Human Body Motion for Biomechanical Analysis2018Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Three-dimensional human movement tracking has long been an important topic in medical and engineering field. Complex camera systems such as Vicon can be used to retrieve very precise motion data. However, the system is more commercial-oriented with a high cost. Besides, it would also be tedious and cumbersome to wear the special markers and suits for tracking. Therefore, there's an urgent need to investigate a cost-effective and markless tool for motion tracking.

    Microsoft Kinect provides a promising solution with a vast variety of libraries, allowing quick development of 3-D spatial modeling and analysis such as moving skeleton possible. For example, the kinematics of the joints such as acceleration, velocity, and angle changes can be deduced from the spatial position information acquired by the camera. In order to validate whether the Kinect system is sufficient for the analysis in practice, a micro-controller platform Arduino along with Intel® Curie™ IMU (Inertial Measurement Unit) module is developed. In particular, the velocity and Euler angels of joint movements, as well as head orientations are measured and compared between the two systems. In this paper, the goal is to present (i) the use of Kinect Depth sensor for data acquisition, (ii) post-processing with the retrieved data, (iii) validation of the Kinect camera.

    Results show that the RMS error of the velocity tracking ranges from 1.78% to 23.34%, presenting a good agreement of measurement between the two systems. Moreover, the relative error of the angle tracking is between 4.0% and 24.3%. The results of the head orientations tracking are hard to perform a mathematical analysis due to the noise and invalid data from the camera caused by the loss of tracking. Overall, the accuracy of joint movement tracked by the Kinect camera, particularly velocity, is proved to be acceptable and the depth camera has been found to be an effective tool for kinematic measurement as a cost-effective option. A platform and workflow are now established, thus making future work regarding validation and application possible when the advanced hardware is available.

  • 3197. Yuen, Pikkei
    Pushing the limits of antibioticsusceptibility testing: - an image analysis approach2015Independent thesis Advanced level (professional degree), 20 poäng / 30 hpOppgave
  • 3198. Yumi Hayashi, S
    et al.
    Mazza do Nascimento, M
    B. L. B,
    Riella, M
    Larsson, M
    Bjällmark, Anna
    Seeberger, A
    Nowak, J
    Lindholm, B
    Brodin, L-Å
    The prevalence of intraventricular dyssynchrony, detected by tissue synchronization imaging, in hemodialysis, peritoneal dialysis and chronic kidney disease stages 3 and 4.2009Konferansepaper (Annet vitenskapelig)
  • 3199. Yumi Hayashi, S
    et al.
    Mazza do Nascimento, M
    Lind, B
    Riella, M
    Larsson, M
    Bjällmark, Anna
    Seeberger, A
    Nowak, J
    Lindholm, B
    Brodin, L-Å
    Improvement of left ventricular synchronicity, assessed by tissue synchronization imaging, after a single hemodialysis session in chronic hemodialysis patients.2009Konferansepaper (Annet vitenskapelig)
  • 3200. Yumi Hayashi, S
    et al.
    Mazza do Nascimento, M
    Lind, B
    Riella, M
    Larsson, M
    Bjällmark, Anna
    Seeberger, A
    Nowak, J
    Lindholm, B
    Brodin, L-Å
    The prevalence of right ventricular dysfunction and the acute effect of HD on right ventricular function in CKD2009Konferansepaper (Annet vitenskapelig)
616263646566 3151 - 3200 of 3295
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