| 1. |
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| 2. |
- Abbaspour Asadollah, Sara, et al.
(författare)
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Evaluation of surface EMG-based recognition algorithms for decoding hand movements
- 2019
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Ingår i: Medical and Biological Engineering and Computing. - : Springer. - 0140-0118 .- 1741-0444. ; 58:1, s. 83-100
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Tidskriftsartikel (refereegranskat)abstract
- Myoelectric pattern recognition (MPR) to decode limb movements is an important advancement regarding the control of powered prostheses. However, this technology is not yet in wide clinical use. Improvements in MPR could potentially increase the functionality of powered prostheses. To this purpose, offline accuracy and processing time were measured over 44 features using six classifiers with the aim of determining new configurations of features and classifiers to improve the accuracy and response time of prosthetics control. An efficient feature set (FS: waveform length, correlation coefficient, Hjorth Parameters) was found to improve the motion recognition accuracy. Using the proposed FS significantly increased the performance of linear discriminant analysis, K-nearest neighbor, maximum likelihood estimation (MLE), and support vector machine by 5.5%, 5.7%, 6.3%, and 6.2%, respectively, when compared with the Hudgins’ set. Using the FS with MLE provided the largest improvement in offline accuracy over the Hudgins feature set, with minimal effect on the processing time. Among the 44 features tested, logarithmic root mean square and normalized logarithmic energy yielded the highest recognition rates (above 95%). We anticipate that this work will contribute to the development of more accurate surface EMG-based motor decoding systems for the control prosthetic hands. [Figure not available: see fulltext.].
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| 3. |
- Abbaspour, S., et al.
(författare)
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Real-Time and Offline Evaluation of Myoelectric Pattern Recognition for the Decoding of Hand Movements
- 2021
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Ingår i: Sensors. - : MDPI AG. - 1424-8220. ; 21:16
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Tidskriftsartikel (refereegranskat)abstract
- Pattern recognition algorithms have been widely used to map surface electromyographic signals to target movements as a source for prosthetic control. However, most investigations have been conducted offline by performing the analysis on pre-recorded datasets. While real-time data analysis (i.e., classification when new data becomes available, with limits on latency under 200-300 milliseconds) plays an important role in the control of prosthetics, less knowledge has been gained with respect to real-time performance. Recent literature has underscored the differences between offline classification accuracy, the most common performance metric, and the usability of upper limb prostheses. Therefore, a comparative offline and real-time performance analysis between common algorithms had yet to be performed. In this study, we investigated the offline and real-time performance of nine different classification algorithms, decoding ten individual hand and wrist movements. Surface myoelectric signals were recorded from fifteen able-bodied subjects while performing the ten movements. The offline decoding demonstrated that linear discriminant analysis (LDA) and maximum likelihood estimation (MLE) significantly (p < 0.05) outperformed other classifiers, with an average classification accuracy of above 97%. On the other hand, the real-time investigation revealed that, in addition to the LDA and MLE, multilayer perceptron also outperformed the other algorithms and achieved a classification accuracy and completion rate of above 68% and 69%, respectively.
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| 4. |
- Absil, Olivier, et al.
(författare)
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An update on the VORTEX project
- 2015
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Ingår i: Techniques and Instrumentation for Detection of Exoplanets VII. - : SPIE.
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Konferensbidrag (refereegranskat)abstract
- In this talk, we will review the on-going activities within the VORTEX teamat the University of Liège and Uppsala University. The VORTEX project aimsto design, manufacture, test, and exploit vector vortex phase masks madeof sub-wavelength gratings (aka the Annular Groove Phase Mask, AGPM)for the direct detection and characterization of extrasolar planets. This talkwill specifically report on the commissioning of several AGPMs on infraredcameras equipping 10-m class telescopes, including the VLT, the LBT andthe Keck. We will describe the in-lab and on-sky performance of the AGPMs,and discuss first scientific observations. We will also report on the lessonslearned from the on-sky operation of our vortices, and discuss ways toimprove their performance. The potential of our coronagraphic devices inthe context of future extremely large telescopes and space missions will alsobe addressed.
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| 5. |
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| 6. |
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| 7. |
- Absil, Olivier, et al.
(författare)
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The VORTEX project : first results and perspectives
- 2014
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Ingår i: Adaptive Optics Systems IV. - : SPIE. - 9780819496164
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Konferensbidrag (refereegranskat)abstract
- Vortex coronagraphs are among the most promising solutions to perform high contrast imaging at small angular separations from bright stars. They feature a very small inner working angle (down to the diffraction limit of the telescope), a clear 360 degree discovery space, have demonstrated very high contrast capabilities, are easy to implement on high-contrast imaging instruments, and have already been extensively tested on the sky. Since 2005, we have been designing, developing and testing an implementation of the charge-2 vector vortex phase mask based on concentric sub-wavelength gratings, referred to as the Annular Groove Phase Mask (AGPM). Science-grade mid-infrared AGPMs were produced in 2012 for the first time, using plasma etching on synthetic diamond substrates. They have been validated on a coronagraphic test bench, showing broadband peak rejection up to 500: 1 in the L band, which translates into a raw contrast of about 6 x 10(-5) at 2 lambda/D. Three of them have now been installed on world-leading diffraction-limited infrared cameras, namely VLT/NACO, VLT/VISIR and LBT/LMIRCam. During the science verification observations with our L-band AGPM on NACO, we observed the beta Pictoris system and obtained unprecedented sensitivity limits to planetary companions down to the diffraction limit (0 : 1 0 0). More recently, we obtained new images of the HR 8799 system at L band during the AGPM first light on LMIRCam. After reviewing these first results obtained with mid-infrared AGPMs, we will discuss the short-and mid-term goals of the on-going VORTEX project, which aims to improve the performance of our vortex phase masks for future applications on second-generation high-contrast imager and on future extremely large telescopes (ELTs). In particular, we will briefly describe our current efforts to improve the manufacturing of mid-infrared AGPMs, to push their operation to shorter wavelengths, and to provide deeper starlight extinction by creating new designs for higher topological charge vortices. Within the VORTEX project, we also plan to develop new image processing techniques tailored to coronagraphic images, and to study some pre- and post-coronagraphic concepts adapted to the vortex coronagraph in order to reduce scattered starlight in the final images.
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| 8. |
- Absil, Oliver, et al.
(författare)
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Three years of harvest with the vector vortex coronagraph in the thermal infrared
- 2016
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Ingår i: Ground-Based and Airborne Instrumentation for Astronomy VI. - : SPIE - International Society for Optical Engineering. - 9781510601963 ; , s. 1-14
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Konferensbidrag (refereegranskat)abstract
- For several years, we have been developing vortex phase masks based on sub-wavelength gratings, known as Annular Groove Phase Masks. Etched onto diamond substrates, these AGPMs are currently designed to be used in the thermal infrared (ranging from 3 to 13 μm). Our AGPMs were first installed on VLT/NACO and VLT/VISIR in 2012, followed by LBT/LMIRCam in 2013 and Keck/NIRC2 in 2015. In this paper, we review the development, commissioning, on-sky performance, and early scientific results of these new coronagraphic modes and report on the lessons learned. We conclude with perspectives for future developments and applications.
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| 9. |
- Ackerley, Rochelle, 1980, et al.
(författare)
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Case Studies in Neuroscience: Sensations elicited and discrimination ability from nerve cuff stimulation in an amputee over time
- 2018
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Ingår i: Journal of Neurophysiology. - : American Physiological Society. - 0022-3077 .- 1522-1598. ; 120:1, s. 291-295
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Tidskriftsartikel (refereegranskat)abstract
- The present case study details sensations elicited by electrical stimulation of peripheral nerve axons using an implanted nerve cuff electrode, in a participant with a transhumeral amputation. The participant uses an osseointegrated electromechanical interface, which enables skeletal attachment of the prosthesis and long-term, stable, bidirectional communication between the implanted electrodes and prosthetic arm. We focused on evoking somatosensory percepts, where we tracked and quantified the evolution of perceived sensations in the missing hand. which were evoked from electrical stimulation of the nerve, for over 2 yr. These sensations included small, pointlike areas of either vibration or pushing, to larger sensations over wider areas, indicating the recruitment of a few and many afferents, respectively. Furthermore, we used a two-alternative forced choice paradigm to measure the level of discrimination between trains of brief electrical stimuli, to gauge what the participant could reliably distinguish between. At best, the participant was able to distinguish a 05-Hz difference and on average acquired a 3.8-Hz just-noticeable difference at a more stringent psychophysical level. The current work shows the feasibility for long-term sensory feedback in prostheses, via electrical axonal stimulation, where small and relatively stable percepts were felt that may be used to deliver graded sensory feedback. This opens up opportunities for signaling feedback during movements (e.g., for precision grip), but also for conveying more complex cutaneous sensations. such as texture. NEW & NOTEWORTHY We demonstrate the long-term stability and generation of sensations from electrical peripheral nerve stimulation in an amputee. through an osseointegrated implant. We find that perceived tactilelike sensations could be generated for over 2 yr. in the missing hand. This is useful for prosthetic development and the implementation of feedback in artificial body parts.
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| 10. |
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| 11. |
- Ahkami, Bahareh, et al.
(författare)
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Electromyography-Based Control of Lower Limb Prostheses: A Systematic Review
- 2023
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Ingår i: IEEE Transactions on Medical Robotics and Bionics. - 2576-3202. ; 5:3, s. 547-562
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Tidskriftsartikel (refereegranskat)abstract
- Most amputations occur in lower limbs and despite improvements in prosthetic technology, no commercially available prosthetic leg uses electromyography (EMG) information as an input for control. Efforts to integrate EMG signals as part of the control strategy have increased in the last decade. In this systematic review, we summarize the research in the field of lower limb prosthetic control using EMG. Four different online databases were searched until June 2022: Web of Science, Scopus, PubMed, and Science Direct. We included articles that reported systems for controlling a prosthetic leg (with an ankle and/or knee actuator) by decoding gait intent using EMG signals alone or in combination with other sensors. A total of 1,331 papers were initially assessed and 121 were finally included in this systematic review. The literature showed that despite the burgeoning interest in research, controlling a leg prosthesis using EMG signals remains challenging. Specifically, regarding EMG signal quality and stability, electrode placement, prosthetic hardware, and control algorithms, all of which need to be more robust for everyday use. In the studies that were investigated, large variations were found between the control methodologies, type of research participant, recording protocols, assessments, and prosthetic hardware.
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| 12. |
- Ahkami, Bahareh, 1994, et al.
(författare)
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Extra-neural signals from severed nerves enable intrinsic hand movements in transhumeral amputations
- 2022
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Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 12:1
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Tidskriftsartikel (refereegranskat)abstract
- Robotic prostheses controlled by myoelectric signals can restore limited but important hand function in individuals with upper limb amputation. The lack of individual finger control highlights the yet insurmountable gap to fully replacing a biological hand. Implanted electrodes around severed nerves have been used to elicit sensations perceived as arising from the missing limb, but using such extra-neural electrodes to record motor signals that allow for the decoding of phantom movements has remained elusive. Here, we showed the feasibility of using signals from non-penetrating neural electrodes to decode intrinsic hand and finger movements in individuals with above-elbow amputations. We found that information recorded with extra-neural electrodes alone was enough to decode phantom hand and individual finger movements, and as expected, the addition of myoelectric signals reduced classification errors both in offline and in real-time decoding.
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| 13. |
- Ahkami, Bahareh, 1994, et al.
(författare)
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Locomotion Decoding (LocoD) An Open-Source Modular Platform for Researching Control of Lower Limb Assistive Devices.
- 2023
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Ingår i: Computer Methods and Programs in Biomedicine. - 1872-7565 .- 0169-2607.
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Tidskriftsartikel (refereegranskat)abstract
- Background and Objective: Commercially available motorized prosthetic legs use exclusively non-biological signals to control movements, such as those provided by load cells, pressure sensors, and inertial measurement units (IMUs). Despite that the use of biological signals of neuromuscular origin can provide more natural control of leg prostheses, these signals cannot yet be captured and decoded reliably enough to be used in daily life. Indeed, decoding motor intention from bioelectric signals obtained from the residual limb holds great potential, and therefore the study of decoding algorithms has increased in the past years with standardized methods yet to be established. Methods: In the absence of shared tools to record and process lower limb bioelectric signals, such as electromyography (EMG), we developed an open-source software platform to unify the recording and processing (pre-processing, feature extraction, and classification) of EMG and non-biological signals amongst researchers with the goal of investigating and benchmarking control algorithms. We validated our locomotion decoding (LocoD) software by comparing the accuracy in the classification of locomotion mode using three different combinations of sensors (1 = IMU+EMG, 2 = EMG, 3 = IMU). EMG and non-biological signals (from the IMU and pressure sensor) were recorded while able-bodied participants (n = 21) walked on different surfaces such as stairs and ramps, and this data set is also released publicly along this publication. LocoD was used for all recording, pre-processing, feature extraction, and classification of the recorded signals. We tested the statistical hypothesis that there was a difference in predicted locomotion mode accuracy between sensor combinations using the Wilcoxon signed-rank test. Results: We found that the sensor combination 1 (EMG+IMU) led to significantly more accurate and improved locomotion mode prediction (Accuracy=93.4 ± 3.9) than using EMG (Accuracy= 74.56 ± 5.8) or IMU alone (Accuracy=90.77 ± 4.6) with p-value < 0.001. Conclusions: Our results support previous research and validate the functionality of LocoD as an open-source and modular platform to research control algorithms for prosthetic legs that incorporate bioelectric signals.
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| 14. |
- Ahkami, Bahareh, 1994, et al.
(författare)
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Probability-Based Rejection of Decoding Output Improves the Accuracy of Locomotion Detection During Gait
- 2023
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Ingår i: Proceedings of the Annual International Conference of the IEEE Engineering in Medicine and Biology Society, EMBS. - 1557-170X.
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Konferensbidrag (refereegranskat)abstract
- Prosthetic users need reliable control over their assistive devices to regain autonomy and independence, particularly for locomotion tasks. Despite the potential for myoelectric signals to reflect the users' intentions more accurately than external sensors, current motorized prosthetic legs fail to utilize these signals, thus hindering natural control. A reason for this challenge could be the insufficient accuracy of locomotion detection when using muscle signals in activities outside the laboratory, which may be due to factors such as suboptimal signal recording conditions or inaccurate control algorithms.This study aims to improve the accuracy of detecting locomotion during gait by utilizing classification post-processing techniques such as Linear Discriminant Analysis with rejection thresholds. We utilized a pre-recorded dataset of electromyography, inertial measurement unit sensor, and pressure sensor recordings from 21 able-bodied participants to evaluate our approach. The data was recorded while participants were ambulating between various surfaces, including level ground walking, stairs, and ramps. The results of this study show an average improvement of 3% in accuracy in comparison with using no post-processing (p-value < 0.05). Participants with lower classification accuracy profited more from the algorithm and showed greater improvement, up to 8% in certain cases. This research highlights the potential of classification post-processing methods to enhance the accuracy of locomotion detection for improved prosthetic control algorithms when using electromyogram signals.Clinical Relevance-Decoding of locomotion intent can be improved using post-processing techniques thus resulting in a more reliable control of lower limb prostheses.
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| 15. |
- Ahmed, Kirstin, 1974, et al.
(författare)
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Validation of IMU against optical reference and development of an open source pipeline: Proof of concept case report in transfemoral amputation fitted with a Percutaneous Osseointegrated Implant
- 2024
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Ingår i: Journal of NeuroEngineering and Rehabilitation. - 1743-0003.
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Tidskriftsartikel (refereegranskat)abstract
- Background Systems that capture motion under laboratory conditions limit validity in real-world environments. Mobile motion capture solutions such as Inertial Measurement Units (IMUs) can progress our understanding of "real" human movement. IMU data must be validated in each application to interpret with clinical applicability; this is particularly true for diverse populations. Our IMU analysis method builds on the OpenSim IMU Inverse Kinematics toolkit integrating the Versatile Quaternion-based Filter and incorporates realistic constraints to the underlying biomechanical model. We validate our processing method against the reference standard optical motion capture in participants with transfemoral amputation fitted with a Percutaneous Osseointegrated Implant (POI) and without amputation. Results Average RMSE between the two systems from the amputated participant (TFA) on the amputated and the intact sides were 2.35 ° (IQR = 1.45 °) and 3.59 ° (IQR = 2.00 °) respectively. Equivalent results without amputation (WA) were 2.26 ° (IQR = 1.08 °). Joint level average RMSE between the two systems from the TFA ranged from 1.66 ° to 3.82 ° and from 1.21 ° to 5.46 ° WA. In plane average RMSE between the two systems from the TFA ranged from 2.17 ° (coronal) to 3.91 ° (sagittal) and from 1.96 ° (transverse) to 2.32 ° (sagittal) WA. CMC results between the two systems in the TFA ranged from 0.74 to > 0.99 and from 0.72 to > 0.99 WA and resulted in ‘excellent’ similarity in each data set average, in every plane and at all joint levels. Normalized RMSE between the two systems from the TFA ranged from 3.40 % (knee level) to 54.54 % (pelvis level) and from 2.18 % to 36.01 % WA. Conclusions We offer a modular processing pipeline that enables the addition of extra layers, facilitates changes to the underlying biomechanical model, and can accept raw IMU data from any vendor. We successfully validate the pipeline using data, for the first time, from a TFA participant using a POI. We have proved our hypothesis that by using this novel pipeline we can validate IMU motion capture data, to a clinically acceptable degree.
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| 16. |
- Aimonen, Kukka, et al.
(författare)
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Role of Surface Chemistry in the In Vitro Lung Response to Nanofibrillated Cellulose
- 2021
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Ingår i: Nanomaterials. - : MDPI. - 2079-4991. ; 11:2
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Tidskriftsartikel (refereegranskat)abstract
- Wood-derived nanofibrillated cellulose (NFC) has emerged as a sustainable material with a wide range of applications and increasing presence in the market. Surface charges are introduced during the preparation of NFC to facilitate the defibrillation process, which may also alter the toxicological properties of NFC. In the present study, we examined the in vitro toxicity of NFCs with five surface chemistries: nonfunctionalized, carboxymethylated, phosphorylated, sulfoethylated, and hydroxypropyltrimethylammonium-substituted. The NFC samples were characterized for surface functional group density, surface charge, and fiber morphology. Fibril aggregates predominated in the nonfunctionalized NFC, while individual nanofibrils were observed in the functionalized NFCs. Differences in surface group density among the functionalized NFCs were reflected in the fiber thickness of these samples. In human bronchial epithelial (BEAS-2B) cells, all NFCs showed low cytotoxicity (CellTiter-GloVR luminescent cell viability assay) which never exceeded 10% at any exposure time. None of the NFCs induced genotoxic effects, as evaluated by the alkaline comet assay and the cytokinesis-block micronucleus assay. The nonfunctionalized and carboxymethylated NFCs were able to increase intracellular reactive oxygen species (ROS) formation (chloromethyl derivative of 2 ',7 '-dichlorodihydrofluorescein diacetate assay). However, ROS induction did not result in increased DNA or chromosome damage.
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| 17. |
- Al-Tashi, Mohammed, et al.
(författare)
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Classroom-ready open-source educational exoskeleton for biomedical and control engineering
- 2024
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Ingår i: Automatisierungstechnik. - 0178-2312. ; 72:5, s. 460-475
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Tidskriftsartikel (refereegranskat)abstract
- In recent years, robotic arm exoskeletons have emerged as promising tools, finding widespread application in the rehabilitation of neurological disorders and as assistive devices for everyday activities, even alleviating the physical strain on labor-intensive tasks. Despite the growing prominence of exoskeletons in everyday life, a notable knowledge gap exists in the availability of open-source platforms for classroom-ready usage in educational settings. To address this deficiency, we introduce an open-source educational exoskeleton platform aimed at Science, Technology, Engineering, and Mathematics (STEM) education. This platform represents an enhancement of the commercial EduExo Pro by AUXIVO, tailored to serve as an educational resource for control engineering and biomedical engineering courses.
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| 18. |
- Andersson, Martin G. I., et al.
(författare)
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Effects of sterilization on dissolved organic carbon (DOC) composition and bacterial utilization of DOC from lakes
- 2018
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Ingår i: Aquatic Microbial Ecology. - : Inter-Research Science Center. - 0948-3055 .- 1616-1564. ; 82:2, s. 199-208
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Tidskriftsartikel (refereegranskat)abstract
- Sterilization of dissolved organic carbon (DOC) is an essential step in research on interactions between DOC and organisms, for example where the effect of different microbial communities on DOC is studied or vice versa. However, few studies have gone beyond acknowledging that sterilization of DOC influences its characteristics. Here, we aimed to provide further knowledge that enables scientists to better tailor their sterilization methods to their research question. To meet this aim, we conducted a sterilization experiment with DOC from 4 boreal lakes treated with 4 sterilization methods, i.e. 2 filtrations (0.2 µm, 0.1 µm) and 2 autoclaving approaches (single and double autoclaving with a single pH adjustment). Quantity and spectroscopic properties of DOC, before and after sterilization, were studied, and DOC was further tested as a substrate for bacterial growth. We found that the filtration methods better preserved the different DOC measures. In contrast, autoclaving caused major inconsistent shifts in both qualitative and quantitative measures of DOC, as well as an increase of the maximum abundance of bacteria in growth experiments. Nonetheless, there remains a trade-off between retaining the quality of DOC and achieving sterile conditions. Therefore, the sterilization method of choice should be guided by the scientific question at hand.
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| 19. |
- Andersson, Martin, et al.
(författare)
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Response and effect interactions between bacterial communities and organic matter
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- The interaction between bacteria and dissolved organic matter (DOM) is crucial for the global carbon cycling. Despite decades of research there are, however, few consistent patterns regarding the relationship between bacterial diversity and community composition and DOM. Here we hypothesized that one reason for such inconsistences among studies is that bacterial communities can adapt to a DOM source over time, whereby a change in the functioning of a community can be, at least partly, decoupled from its composition and diversity. To test this idea we performed a reciprocal transplant experiment with medium (i.e. DOM source) and bacterial communities from two boreal lakes. In this experiment the two communities were allowed to adapt to their indigenous and their foreign source of DOM over 42 days. Bacterial community composition (BCC) was measured throughout the experiment. In addition we measured the capacity of the communities to use DOM, in repeated short (5 days) separated bioassays. The results show a response of bacterial community composition to the DOM sources which was influenced by the origin of the community. In contrast, we could not show an effect of BCC on DOM-processing and functional performance. Indeed, communities of different origin processed the two DOM sources equally well even at the beginning of the experiment. This work demonstrates that the DOM pool can be a strong selective force for BCC but not vice versa.
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| 20. |
- Andersson, Martin, et al.
(författare)
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The relative importance of richness and BCC for DOC degradation
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- The importance of biodiversity has been of primary interest for ecologist the last 20 years, giving rise to biodiversity ecosystem function (BEF) studies. Within the traditional field of ecology reoccurring patterns have emerged but within microbial ecology the importance of species richness for functioning is still poorly understood with few consistent patterns. In this study we examined the effect of species richness for dissolved organic matter degradation in lakes. This was examined within a smaller span of species richness compared to what is typically in microbial BEF experiments. Bacterial communities of reduced species richness were exposed to a range of DOC environments to test if reduced richness changed the functioning of communities and if the effect was similar among DOC environments. This was conducted in a full factorial design of 3 levels, with 6 dilutions, 5 media and 3 inocula resulting in 90 treatments. Overall, richness and community composition appeared to have effects on DOC degradation, but these effects were minor compared to the variation caused by the different DOC sources. Further, the importance of species richness varied among media and, thus, the chemical complexity of the environment influenced the biodiversity-ecosystem functioning relationship.
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| 21. |
- Arrázola, Macarena S., et al.
(författare)
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Axonal degeneration is mediated by necroptosis activation
- 2019
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Ingår i: The Journal of Neuroscience. - 0270-6474. ; 39:20, s. 3832-3844
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Tidskriftsartikel (refereegranskat)abstract
- Axonal degeneration, which contributes to functional impairment in several disorders of the nervous system, is an important target for neuroprotection. Several individual factors and subcellular events have been implicated in axonal degeneration, but researchers have so far been unable to identify an integrative signaling pathway activating this self-destructive process. Through pharmacological and genetic approaches, we tested whether necroptosis, a regulated cell-death mechanism implicated in the pathogenesis of several neurodegenerative diseases, is involved in axonal degeneration. Pharmacological inhibition of the necroptotic kinase RIPK1 using necrostatin-1 strongly delayed axonal degeneration in the peripheral nervous system and CNS of wild-type mice of either sex and protected in vitro sensory axons from degeneration after mechanical and toxic insults. These effects were also observed after genetic knock-down of RIPK3, a second key regulator of necroptosis, and the downstream effector MLKL (Mixed Lineage Kinase Domain-Like). RIPK1 inhibition prevented mitochondrial fragmentation in vitro and in vivo, a typical feature of necrotic death, and inhibition of mitochondrial fission by Mdivi also resulted in reduced axonal loss in damaged nerves. Furthermore, electrophysiological analysis demonstrated that inhibition of necroptosis delays not only the morphological degeneration of axons, but also the loss of their electrophysiological function after nerve injury. Activation of the necroptotic pathway early during injury-induced axonal degeneration was made evident by increased phosphorylation of the downstream effector MLKL. Our results demonstrate that axonal degeneration proceeds by necroptosis, thus defining a novel mechanistic framework in the axonal degenerative cascade for therapeutic interventions in a wide variety of conditions that lead to neuronal loss and functional impairment.
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| 22. |
- Attermeyer, Katrin, et al.
(författare)
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Carbon dioxide fluxes increase from day to night across European streams
- 2021
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Ingår i: Communications Earth & Environment. - : Springer Nature. - 2662-4435. ; 2:1
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Tidskriftsartikel (refereegranskat)abstract
- Globally, inland waters emit over 2 Pg of carbon per year as carbon dioxide, of which the majority originates from streams and rivers. Despite the global significance of fluvial carbon dioxide emissions, little is known about their diel dynamics. Here we present a large-scale assessment of day- and night-time carbon dioxide fluxes at the water-air interface across 34 European streams. We directly measured fluxes four times between October 2016 and July 2017 using drifting chambers. Median fluxes are 1.4 and 2.1mmolm(-2) h(-1) at midday and midnight, respectively, with night fluxes exceeding those during the day by 39%. We attribute diel carbon dioxide flux variability mainly to changes in the water partial pressure of carbon dioxide. However, no consistent drivers could be identified across sites. Our findings highlight widespread day-night changes in fluvial carbon dioxide fluxes and suggest that the time of day greatly influences measured carbon dioxide fluxes across European streams. Diel patterns can greatly impact total stream carbon dioxide emissions, with 39% greater carbon dioxide flux during the night-time relative to the day-time, according to a study of 34 streams across Europe.
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| 23. |
- Attermeyer, Katrin, et al.
(författare)
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Organic Carbon Processing During Transport Through Boreal Inland Waters : Particles as Important Sites
- 2018
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Ingår i: Journal of Geophysical Research - Biogeosciences. - 2169-8953 .- 2169-8961. ; 123:8, s. 2412-2428
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Tidskriftsartikel (refereegranskat)abstract
- The degradation and transformation of organic carbon (C) in inland waters result in significant CO2 emissions from inland waters. Even though most of the C in inland waters occurs as dissolved organic carbon (DOC), studies on particulate organic carbon (POC) and how it influences the overall reactivity of organic C in transport are still scarce. We sampled 30 aquatic ecosystems following an aquatic continuum including peat surface waters, streams, rivers, and lakes. We report DOC and POC degradation rates, relate degradation patterns to environmental data across these systems, and present qualitative changes in dissolved organic matter and particulate organic matter during degradation. Microbial degradation rates of POC were approximately 15 times higher compared to degradation of DOC, with POC half-lives of only 17 +/- 3 (mean +/- SE) days across all sampled aquatic ecosystems. Rapid POC decay was accompanied by a shift in particulate C: N ratios, whereas dissolved organic matter composition did not change at the time scale of incubations. The faster degradation of the POC implies a constant replenishment to sustain natural POC concentrations. We suggest that degradation of organic matter transported through the inland water continuum might occur to a large extent via transition of DOC into more rapidly cycling POC in nature, for example, triggered by light. In this way, particles would be a dominant pool of organic C processing across the boreal aquatic continuum, partially sustained by replenishment via flocculation of DOC.
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| 24. |
- Attermeyer, Katrin, et al.
(författare)
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Potential terrestrial influence on transparent exopolymer particle (TEP) concentrations in boreal freshwaters
- 2019
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Ingår i: Journal of limnology. - : Wiley. - 1129-5767 .- 1723-8633. ; 64:6, s. 2455-2466
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Tidskriftsartikel (refereegranskat)abstract
- Transparent exopolymer particles (TEP) are ubiquitous in aquatic ecosystems and contribute, for example, to sedimentation of organic matter in oceans and freshwaters. Earlier studies indicate that the formation of TEP is related to the in situ activity of phytoplankton or bacteria. However, terrestrial sources of TEP and TEP precursors are usually not considered. We investigated TEP concentration and its driving factors in boreal freshwaters, hypoth- esizing that TEP and TEP precursors can enter freshwaters via terrestrial inputs. In a field survey, we measured TEP concentrations and other environmental factors across 30 aquatic ecosystems in Sweden. In a mesocosm experi- ment, we further investigated TEP dynamics over time after manipulating terrestrial organic matter input and light conditions. The TEP concentrations in boreal freshwaters ranged from 83 to 4940 μg Gum Xanthan equivalent L−1, which is comparable to other studies in freshwaters. The carbon fraction in TEP in the sampled boreal freshwaters is much higher than the phytoplanktonic carbon, in contrast to previous studies in northern temperate and Medi- terranean regions. Boreal TEP concentrations were mostly related to particulate organic carbon, dissolved organic carbon, and optical indices of terrestrial influence but less influenced by bacterial abundance, bacterial production, and chlorophyll a. Hence, our results do not support a major role of the phytoplankton community or aquatic bac- teria on TEP concentrations and dynamics. This suggests a strong external control of TEP concentrations in boreal freshwaters, which can in turn affect particle dynamics and sedimentation in the recipient aquatic ecosystem.
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| 25. |
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| 26. |
- Ayarza, Puy, et al.
(författare)
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Evolution of the Iberian Massif as deduced from its crustal thickness and geometry of a mid-crustal (Conrad) discontinuity
- 2021
-
Ingår i: Solid Earth. - : Copernicus Publications. - 1869-9510 .- 1869-9529. ; 12:7, s. 1515-1547
-
Tidskriftsartikel (refereegranskat)abstract
- Y Normal incidence seismic data provide the best images of the crust and lithosphere. When properly designed and continuous, these sections greatly contribute to understanding the geometry of orogens and, along with surface geology, unraveling their evolution. In this paper we present the most complete transect, to date, of the Iberian Massif, the westernmost exposure of the European Variscides. Despite the heterogeneity of the dataset, acquired during the last 30 years, the images resulting from reprocessing the data with a homogeneous workflow allow us to clearly define the crustal thickness and its internal architecture. The Iberian Massif crust, formed by the amalgamation of continental pieces belonging to Gondwana and Laurussia (Avalonian margin), is well structured in the upper and lower crust. A conspicuous mid-crustal discontinuity is clearly defined by the top of the reflective lower crust and by the asymptotic geometry of reflections that merge into it, suggesting that it has often acted as a detachment. The geometry and position of this discontinuity can give us insights into the evolution of the orogen (i.e., of the magnitude of compression and the effects and extent of later-Variscan gravitational collapse). Moreover, the limited thickness of the lower crust below, in central and northwestern Iberia, might have constrained the response of the Iberian microplate to Alpine shortening. Here, this discontinuity, featuring a Vp (P-wave velocity) increase, is observed as an orogen-scale boundary with characteristics compatible with those of the globally debated Conrad discontinuity.
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| 27. |
- Ayarza, P., et al.
(författare)
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Geophysical constraints on the structure of a limited ocean-continent subduction zone at the north Iberian margin
- 2004
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Ingår i: Tectonics. ; 23, s. 1010-
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Tidskriftsartikel (refereegranskat)abstract
- Late Cretaceous to Cenozoic convergence between Iberia and Europe led to the partial closure of the Bay of Biscay with limited southward subduction of oceanic crust below the North Iberian Margin. Inclined sub-Moho reflections and diffractions observed in deep seismic reflection profiles shot across the margin are especially well represented in two reflection profiles: ESCIN-3.2 and ESCIN-3.3. These two profiles have been chosen to test if the sub-Moho reflections correspond to true primary deep events and, provided that they are reflecting off the subduction zone, to investigate its deep structure. Spectral analysis together with travel time estimation and migration allow us to characterize a number of these sub-Moho events as deep-source, low-frequency (∼19 Hz), reflections and diffractions. Synthetic seismograms were generated by three-dimensional seismic modeling of a sub-Moho southward dipping surface, interpreted to correspond to the top of subducted oceanic crust. Comparison between the real and synthetic data show that inclined, low-frequency sub-Moho reflections in both, ESCIN-3.2 and ESCIN-3.3 profiles may correspond to reflections from southward subducted Bay of Biscay oceanic crust. Geoid, free-air gravity, and absolute topography modeling provides additional constraints on the lithospheric-scale structure of this limited ocean-continent subduction zone beneath the North Iberian Margin.
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| 28. |
- Bengtsson, Mia M., et al.
(författare)
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Interactive effects on organic matter processing from soils to the ocean : are priming effects relevant in aquatic ecosystems?
- 2018
-
Ingår i: Hydrobiologia. - : Springer. - 0018-8158 .- 1573-5117. ; 822:1, s. 1-17
-
Forskningsöversikt (refereegranskat)abstract
- Organic matter (OM) is degraded during transport from soils to oceans. However, there are spatial and temporal variabilities along the aquatic continuum, which hamper the development of carbon cycling models. One concept that has been applied in this context is the priming effect (PE), describing non-additive effects on OM degradation after mixing sources of contrasting bioavailability. Studies on the aquatic PE report divergent results from positive (increased OM degradation rates) to neutral, to negative (decreased OM degradation rates) effects upon mixing. Here, we aim to condense the outcomes of these studies on aquatic PE. Based on a literature review, we discuss differences in the reported PEs across freshwater and marine ecosystems, identifying system-specific features that could favour non-additive effects on OM degradation. Using a quantitative meta-analysis approach, we evaluated the occurrence, direction (positive vs. negative) and magnitude of aquatic PE. The meta-analysis revealed a mean PE of 12.6%, which was not significantly different from zero across studies. Hence, mixing of contrasting OM sources in aquatic ecosystems does not necessarily result in a change in OM degradation rates. Therefore, we suggest to focus on molecular and microbial diversity and function, which could provide a better mechanistic understanding of processes driving OM interactions.
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| 29. |
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| 30. |
- Birkby, J. L., et al.
(författare)
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WTS-2 b: a hot Jupiter orbiting near its tidal destruction radius around a K dwarf
- 2014
-
Ingår i: Monthly Notices of the Royal Astronomical Society. - : Oxford University Press (OUP). - 1365-2966 .- 0035-8711. ; 440:2, s. 1470-1489
-
Tidskriftsartikel (refereegranskat)abstract
- We report the discovery of WTS-2 b, an unusually close-in 1.02-d hot Jupiter (M-P = 1.12M(J), R-P = 1.30R(J)) orbiting a K2V star, which has a possible gravitationally bound M-dwarf companion at 0.6 arcsec separation contributing similar to 20 per cent of the total flux in the observed J-band light curve. The planet is only 1.5 times the separation from its host star at which it would be destroyed by Roche lobe overflow, and has a predicted remaining lifetime of just similar to 40 Myr, assuming a tidal dissipation quality factor of Q(*)' = 10(6).Q(*)' is a key factor in determining how frictional processes within a host star affect the orbital evolution of its companion giant planets, but it is currently poorly constrained by observations. We calculate that the orbital decay of WTS-2 b would correspond to a shift in its transit arrival time of T-shift similar to 17 s after 15 yr assuming Q(*)' = 10(6). A shift less than this would place a direct observational constraint on the lower limit of Q(*)' in this system. We also report a correction to the previously published expected T-shift for WASP-18 b, finding that T-shift = 356 s after 10 yr for Q(*)' = 10(6), which is much larger than the estimated 28 s quoted in WASP-18 b discovery paper. We attempted to constrain Q(*)' via a study of the entire population of known transiting hot Jupiters, but our results were inconclusive, requiring a more detailed treatment of transit survey sensitivities at long periods. We conclude that the most informative and straightforward constraints on Q(*)' will be obtained by direct observational measurements of the shift in transit arrival times in individual hot Jupiter systems. We show that this is achievable across the mass spectrum of exoplanet host stars within a decade, and will directly probe the effects of stellar interior structure on tidal dissipation.
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| 31. |
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| 32. |
- Björkquist, Anna, et al.
(författare)
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Towards Implementation of a Home-Based Phantom Limb Pain Treatment Facilitated by Textile-Electrode System - A Case Study
- 2023
-
Ingår i: Caring is Sharing — Exploiting the Value in Data for Health and Innovation. - : IOS Press. - 9781643683881 - 9781643683898 ; , s. 682-683
-
Konferensbidrag (refereegranskat)abstract
- This case study reports the use of a new textile-electrode system for self-administered Phantom Motor Execution (PME) treatment at home in one patient with Phantom Limb Pain (PLP). In follow-up interviews, the patient reported reduced pain, increased mobility, and improved mental health, and aspects such as motivation, usability, support, and treatment outcome, could be recognized from an earlier study as crucial for successful implementation and adoption of the home-based long-term treatment. The findings are of interest to developers, providers, users, and researchers planning home-based clinical studies and/or scenarios based on technology-assisted treatment.
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| 33. |
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| 34. |
- Boni, Irene, et al.
(författare)
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Restoring Natural Forearm Rotation in Transradial Osseointegrated Amputees
- 2018
-
Ingår i: IEEE Transactions on Neural Systems and Rehabilitation Engineering. - 1558-0210 .- 1534-4320. ; 26:12, s. 2333-2341
-
Tidskriftsartikel (refereegranskat)abstract
- Osseointegrated transradial prostheses have the potential to preserve the natural range of wrist rotation, which improves the performance of activities of daily living and reduces compensatory movements that potentially lead to secondary health problems over time. This is possible by enabling the radius and the ulna bone to move with respect to each other, restoring the functionality of the original distal-radioulnar joint. In this paper, we report on psychophysics tests performed on an osseointegrated transradial amputee with the aim to understand the extent of mobility of the implants that is required to preserve the natural forearm rotation. Based on these experiments, we designed and developed an attachment device between the implants and the hand prosthesis that serves as an artificial distal radio-ulnar joint. This device was fitted on an osseointegrated transradial amputee and its functionality assessed by means of the Southampton Hand Assessment Procedure (SHAP) and the Minnesota Manual Dexterity test (MMDT). We found that the axial rotation of the implants is required to preserve forearm rotation, to distribute loads equally over the two implants (60% radius - 40% ulna), and to enable loading of the implants without unpleasant feelings for the patient. Higher function was recorded when our attachment device enabled forearm rotation: SHAP from 61 to 71, MMDT from 258s to 231s. Natural forearm rotation can be successfully restored in transradial amputees by using osseointegration and our novel mechanical attachment to the hand prosthesis.
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| 35. |
- Bravo, Andrea G., et al.
(författare)
-
The interplay between total mercury, methylmercury and dissolved organic matter in fluvial systems : A latitudinal study across Europe
- 2018
-
Ingår i: Water Research. - : Elsevier. - 0043-1354 .- 1879-2448. ; 144, s. 172-182
-
Tidskriftsartikel (refereegranskat)abstract
- Large-scale studies are needed to identify the drivers of total mercury (THg) and monomethyl-mercury (MeHg) concentrations in aquatic ecosystems. Studies attempting to link dissolved organic matter (DOM) to levels of THg or MeHg are few and geographically constrained. Additionally, stream and river systems have been understudied as compared to lakes. Hence, the aim of this study was to examine the influence of DOM concentration and composition, morphological descriptors, land uses and water chemistry on THg and MeHg concentrations and the percentage of THg as MeHg (%MeHg) in 29 streams across Europe spanning from 41°N to 64°N. THg concentrations (0.06–2.78 ng L−1) were highest in streams characterized by DOM with a high terrestrial soil signature and low nutrient content. MeHg concentrations (7.8–159 pg L−1) varied non-systematically across systems. Relationships between DOM bulk characteristics and THg and MeHg suggest that while soil derived DOM inputs control THg concentrations, autochthonous DOM (aquatically produced) and the availability of electron acceptors for Hg methylating microorganisms (e.g. sulfate) drive %MeHg and potentially MeHg concentration. Overall, these results highlight the large spatial variability in THg and MeHg concentrations at the European scale, and underscore the importance of DOM composition on mercury cycling in fluvial systems.
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| 36. |
- Bravo, Andrea G., et al.
(författare)
-
The interplay between total mercury, methylmercury and dissolved organic matter in fluvial systems : A latitudinal study across Europe
- 2018
-
Ingår i: Water Research. - : Pergamon. - 0043-1354 .- 1879-2448. ; 144, s. 172-182
-
Tidskriftsartikel (refereegranskat)abstract
- Large-scale studies are needed to identify the drivers of total mercury (THg) and monomethyl-mercury (MeHg) concentrations in aquatic ecosystems. Studies attempting to link dissolved organic matter (DOM) to levels of THg or MeHg are few and geographically constrained. Additionally, stream and river systems have been understudied as compared to lakes. Hence, the aim of this study was to examine the influence of DOM concentration and composition, morphological descriptors, land uses and water chemistry on THg and MeHg concentrations and the percentage of THg as MeHg (%MeHg) in 29 streams across Europe spanning from 41°N to 64 °N. THg concentrations (0.06–2.78 ng L−1) were highest in streams characterized by DOM with a high terrestrial soil signature and low nutrient content. MeHg concentrations (7.8–159 pg L−1) varied non-systematically across systems. Relationships between DOM bulk characteristics and THg and MeHg suggest that while soil derived DOM inputs control THg concentrations, autochthonous DOM (aquatically produced) and the availability of electron acceptors for Hg methylating microorganisms (e.g. sulfate) drive %MeHg and potentially MeHg concentration. Overall, these results highlight the large spatial variability in THg and MeHg concentrations at the European scale, and underscore the importance of DOM composition on mercury cycling in fluvial systems.
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| 37. |
- Brown, Shannon, et al.
(författare)
-
Intarsia-sensorized band and textrodes for real-time myoelectric pattern recognition
- 2016
-
Ingår i: Engineering in Medicine and Biology Society (EMBC), 2016 IEEE 38th Annual International Conference of the. - : Institute of Electrical and Electronics Engineers (IEEE). - 1557-170X. - 9781457702204 ; , s. 6074-6077
-
Konferensbidrag (refereegranskat)abstract
- Surface Electromyography (sEMG) has applications in prosthetics, diagnostics and neuromuscular rehabilitation. Self-adhesive Ag/AgCl are the electrodes preferentially used to capture sEMG in short-term studies, however their long-term application is limited. In this study we designed and evaluated a fully integrated smart textile band with electrical connecting tracks knitted with intarsia techniques and knitted textile electrodes. Real-time myoelectric pattern recognition for motor volition and signal-to-noise ratio (SNR) were used to compare its sensing performance versus the conventional Ag-AgCl electrodes. After a comprehending measurement and performance comparison of the sEMG recordings, no significant differences were found between the textile and the Ag-AgCl electrodes in SNR and prediction accuracy obtained from pattern recognition classifiers.
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| 38. |
- Brown, Shannon, et al.
(författare)
-
Intarsia-Sensorized Band and Textrodes for the Acquisition of Myoelectric Signals
- 2016
-
Ingår i: The Second International Conference on Smart Portable, Wearable, Implantable and Disability-oriented Devices and Systems. - : International Academy, Research and Industry Association (IARIA). - 9781612084800 ; , s. 14-19
-
Konferensbidrag (refereegranskat)abstract
- Surface Electromyography (sEMG) has applications in prosthetics, diagnostics and neuromuscular rehabilitation, and has been an increasing area of study. This study attempts to use a fully integrated smart textile band with electrical connecting tracks knitted with intarsia techniques to evaluate the quality of sEMG acquired by knitted textile electrodes. Myoelectric pattern recognition for motor volition and signal-to-noise ratio (SNR) were used to compare its sensing performance versus the conventional Ag-AgCl electrodes. Overall no significant differences were found between the textile and the Ag-AgCl electrodes in SNR and prediction accuracy obtained from pattern recognition classifiers. On average the textile electrodes produced a high prediction accuracy, >97% across all movements, which is equivalent to the accuracy obtained with conventional gel electrodes (Ag-AgCl). Furthermore the SNR for the Maximum Voluntary Contraction did not differ considerably between the textile and the Ag-AgCl electrodes.
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| 39. |
- Buist, Mirka, et al.
(författare)
-
Development and Validation of a Wearable Device to Provide Rich Somatosensory Stimulation for Rehabilitation After Sensorimotor Impairment
- 2023
-
Ingår i: IEEE Transactions on Biomedical Circuits and Systems. - : Institute of Electrical and Electronics Engineers (IEEE). - 1932-4545 .- 1940-9990. ; 17:3, s. 547-557
-
Tidskriftsartikel (refereegranskat)abstract
- Training sensory discrimination of the skin has the potential to reduce chronic pain due to sensorimotor impairments and increase sensorimotor function. Currently, there is no such device that can systematically provide rich skin stimulation suitable for a training protocol for individuals with amputation or major sensory impairment. This study describes the development and validation of a non-invasive wearable device meant to repeatedly and safely deliver somatosensory stimulations. The development was guided by a structured design control process to ensure the verifiability and validity of the design outcomes. Two sub-systems were designed: 1) a tactile display for touch and vibration sensations, and 2) a set of bands for sliding, pressure, and strain sensations. The device was designed with a versatile structure that allows for its application on different body parts. We designed a device-paired interactive computer program to enable structured sensory training sessions. Validation was performed with 11 individuals with intact limbs whose upper arm tactile sensitivity was measured over 5 training sessions. Tactile discrimination and perception threshold were measured using the standard 2-point discrimination and Semmes-Weinstein monofilament tests, respectively. The results of the monofilament test showed a significant improvement (p = 0.011), but the improvement was not significant for the 2-point discrimination test(p = 0.141). These promising results confirm the potential of the proposed training to increase the sensory acuity in the upper arms of individuals with intact limbs. Further studies will be conducted to determine how to transfer the findings of this work to improve the pain and/or functional rehabilitation in individuals with sensorimotor impairments.
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| 40. |
- Buist, Mirka, et al.
(författare)
-
Development and Validation of a Wearable Device to Provide Rich Somatosensory Stimulation for Rehabilitation After Sensorimotor Impairment
- 2023
-
Ingår i: Ieee Transactions on Biomedical Circuits and Systems. - 1932-4545. ; 17:3, s. 547-557
-
Tidskriftsartikel (refereegranskat)abstract
- Training sensory discrimination of the skin has the potential to reduce chronic pain due to sensorimotor impairments and increase sensorimotor function. Currently, there is no such device that can systematically provide rich skin stimulation suitable for a training protocol for individuals with amputation or major sensory impairment. This study describes the development and validation of a non-invasive wearable device meant to repeatedly and safely deliver somatosensory stimulations. The development was guided by a structured design control process to ensure the verifiability and validity of the design outcomes. Two sub-systems were designed: 1) a tactile display for touch and vibration sensations, and 2) a set of bands for sliding, pressure, and strain sensations. The device was designed with a versatile structure that allows for its application on different body parts. We designed a device-paired interactive computer program to enable structured sensory training sessions. Validation was performed with 11 individuals with intact limbs whose upper arm tactile sensitivity was measured over 5 training sessions. Tactile discrimination and perception threshold were measured using the standard 2-point discrimination and Semmes-Weinstein monofilament tests, respectively. The results of the monofilament test showed a significant improvement (p = 0.011), but the improvement was not significant for the 2-point discrimination test(p = 0.141). These promising results confirm the potential of the proposed training to increase the sensory acuity in the upper arms of individuals with intact limbs. Further studies will be conducted to determine how to transfer the findings of this work to improve the pain and/or functional rehabilitation in individuals with sensorimotor impairments.
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| 41. |
- Buist, Mirka, et al.
(författare)
-
Novel Wearable Device for Mindful Sensorimotor Training: Integrating Motor Decoding and Somatosensory Stimulation for Neurorehabilitation
- 2024
-
Ingår i: IEEE Transactions on Neural Systems and Rehabilitation Engineering. - : Institute of Electrical and Electronics Engineers (IEEE). - 1558-0210 .- 1534-4320. ; 32, s. 1515-1523
-
Tidskriftsartikel (refereegranskat)abstract
- Sensorimotor impairment is a prevalent condition requiring effective rehabilitation strategies. This study introduces a novel wearable device for Mindful Sensorimotor Training (MiSMT) designed for sensory and motor rehabilitation. Our MiSMT device combines motor training using myoelectric pattern recognition along sensory training using two tactile displays. This device offers a comprehensive solution, integrating electromyography and haptic feedback, lacking in existing devices. The device features eight electromyography channels, a rechargeable battery, and wireless Bluetooth or Wi-Fi connectivity for seamless communication with a computer or mobile device. Its flexible material allows for adaptability to various body parts, ensuring ease of use in diverse patients. The two tactile displays, with 16 electromagnetic actuators each, provide touch and vibration sensations up to 250 Hz. In this proof-of-concept study, we show improved two-point discrimination after 5 training sessions in participants with intact limbs (p=0.047). We also demonstrated successful acquisition, processing, and decoding of myoelectric signals in offline and online evaluations. In conclusion, the MiSMT device presents a promising tool for sensorimotor rehabilitation by combining motor execution and sensory training benefits. Further studies are required to assess its effectiveness in individuals with sensorimotor impairments. Integrating mindful sensory and motor training with innovative technology can enhance rehabilitation outcomes and improve the quality of life for those with sensorimotor impairments.
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| 42. |
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| 43. |
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| 44. |
- Carlomagno, Brunella, et al.
(författare)
-
Design and performance simulations of mid-IR AGPMs for ELT/METIS applications
- 2015
-
Konferensbidrag (refereegranskat)abstract
- The direct detection of exoplanets requires the use of dedicated, highcontrast imaging instruments. In this context, vector vortex coronagraphs(VVCs) are considered to be among the most promising solutions to reachhigh contrast at small angular separations. They feature a small innerworking angle (down to 0.9 lambda/D), high throughput, clear off-axis360° discovery space, and are simple to implement. The AGPM (AnnularGroove Phase Mask) is an implementation of the vortex phase mask, whichprovides achromaticity over an appreciable spectral range thanks to the useof sub-wavelength gratings. The grating profile can be optimized based onthe rigorous coupled wave analysis (RCWA) to achieve a quasi-achromaticphase shift up to a very broad band (L+M band: 3.5-5.1μm). These deviceshave been manufactured onto CVD diamond substrates, using reactiveion etching. In this communication, I will first present the latest RCWAConference 9605: Techniques and Instrumentationfor Detection of Exoplanets VIIR eturn to Contents +1 360 676 3290 · help@spie.org 631simulations performed in the L, M and N spectral bands, and for somecombinations of these bands. The resulting optimized AGPMs could beperfectly integrated in the E-ELT/METIS instrument, which aims at detectingand characterizing exoplanets by direct imaging. The target contrast forMETIS is <1e-4 at 2 lambda/D (~40 mas in L band), which translates into apeak rejection rate of few hundreds for the AGPMs. Secondly, the opticalpropagation within the METIS instrument will be studied to determine theperformances of a vortex coronagraph at the focus of METIS. In particular,the effect of the central obstruction, spiders, missing E-ELT segments,and pointing jitter will be analysed, together with the sensitivity to tip-tilt.Finally, the atmosphere and the AO contributions will be considered toobtain more realistic results.
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| 45. |
- Carlomagno, Brunella, et al.
(författare)
-
End-to-end simulations of the E-ELT/METIS coronagraphs
- 2016
-
Ingår i: Adaptive Optics Systems V. - : SPIE - International Society for Optical Engineering. ; , s. 1-10
-
Konferensbidrag (refereegranskat)abstract
- The direct detection of low-mass planets in the habitable zone of nearby stars is an important science case for future E-ELT instruments such as the mid-infrared imager and spectrograph METIS, which features vortex phase masks and apodizing phase plates (APP) in its baseline design. In this work, we present end-to-end performance simulations, using Fourier propagation, of several METIS coronagraphic modes, including focal-plane vortex phase masks and pupil-plane apodizing phase plates, for the centrally obscured, segmented E-ELT pupil. The atmosphere and the AO contributions are taken into account. Hybrid coronagraphs combining the advantages of vortex phase masks and APPs are considered to improve the METIS coronagraphic performance.
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| 46. |
- Carlomagno, Brunella, et al.
(författare)
-
Mid-IR AGPMs for ELT applications
- 2014
-
Ingår i: GROUND-BASED AND AIRBORNE INSTRUMENTATION FOR ASTRONOMY V. - : SPIE. - 9780819496157
-
Konferensbidrag (refereegranskat)abstract
- The mid-infrared region is well suited for exoplanet detection thanks to the reduced contrast between the planet and its host star with respect to the visible and near-infrared wavelength regimes. This contrast may be further improved with Vector Vortex Coronagraphs (VVCs), which allow us to cancel the starlight. One flavour of the VVC is the AGPM (Annular Groove Phase Mask), which adds the interesting properties of subwavelength gratings (achromaticity, robustness) to the already known properties of the VVC. In this paper, we present the optimized designs, as well as the expected performances of mid-IR AGPMs etched onto synthetic diamond substrates, which are considered for the E-ELT/METIS instrument.
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| 47. |
- Carlomagno, Brunella, et al.
(författare)
-
Performance evaluation of mid-IR vortex coronagraphs with centrally obscured segmented pupils
- 2015
-
Konferensbidrag (refereegranskat)abstract
- In its original design, the E-ELT/Metis instrument envisages a vortex coronagraph in the mid-IR regime for detection and characterization of exoplanets, with a contrast of 1e-4 at 2 lambda/D (~40 mas in L band). The AGPM (Annular Groove Phase Mask) is a vortex phase mask with impressive characteristics: small inner working angle, high throughput, achromaticity. A non-perfectly circular pupil and non-flat input wavefront result in a starlight leakage, degrading the performance of the vortex coronagraph. In this work, we present end-to-end performance simulations using Fourier optical propagation to determine the quality of the starlight rejection obtained with an infrared vortex coronagraph. We first analyse the performance facing E-ELT pupil variations (segmentations, central obscuration, spiders, missing segments), then pointing jitter and random adaptive optics residual phase screens are introduced to derive more realistic performance. Finally, more advanced concepts of the infrared vortex coronagraph are presented, in order to compensate for performance degradation.
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| 48. |
- Casas-Ruiz, Joan P., et al.
(författare)
-
A tale of pipes and reactors : Controls on the in-stream dynamics of dissolved organic matter in rivers
- 2017
-
Ingår i: Limnology and Oceanography. - : Wiley. - 0024-3590 .- 1939-5590. ; 62, s. S85-S94
-
Tidskriftsartikel (refereegranskat)abstract
- The potential for rivers to alter the flux of dissolved organic matter (DOM) from land to ocean is widely accepted. Yet anticipating when and where rivers behave as active reactors vs. passive pipes of DOM stands as a major knowledge gap in river biogeochemistry, resulting in uncertainties for global carbon models. Here, we investigate the controls on in-stream DOM dynamics by evaluating changes in DOM concentration and composition along several reaches of a medium-sized river network over one full hydrological year. Roughly half of the observations over time and space showed active reactor conditions and, among these, similar pro-portion of gains and losses was measured. High water residence times promoted the active over passive behavior of the reaches, while DOM properties and nitrate availability determined whether they supplied or removed DOM from the river. Among different DOM fractions, protein-like DOM both of terrestrial and aquatic origin seemed to drive bulk DOM patterns. Our study emphasizes the role of water residence time as a physical constraint for in-stream processes, and provides new insights into the key factors governing the net balance between in-stream gains and losses of DOM in rivers.
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| 49. |
- Casas-Ruiz, Joan P., et al.
(författare)
-
Drought-induced discontinuities in the source and degradation of dissolved organic matter in a Mediterranean river
- 2016
-
Ingår i: Biogeochemistry. - : Springer Science and Business Media LLC. - 0168-2563 .- 1573-515X. ; 127:1, s. 125-139
-
Tidskriftsartikel (refereegranskat)abstract
- The composition of dissolved organic matter (DOM) in rivers results from the different sources and in-stream transformations along the land to ocean aquatic continuum. Riverine DOM sources are highly dependent on the hydrological connection between the river channel and the surrounding terrestrial ecosystems, but how the lack of this connectivity (e.g., during drought episodes) affects the sources and biodegradation of DOM in rivers remains unclear. Here we identified the DOM sources as well as the different DOM pools that are respired along a Mediterranean river during drought by combining absorbance-fluorescence spectroscopy, size-exclusion chromatography, biodegradation assays, and stable and radiocarbon isotopes. DOM composition was highly heterogeneous along the river in response to different sources and in-stream processes in each distinct aquatic environment (i.e., isolated water pools, running waters, and impounded waters in weirs). The reduced hydrological connectivity with terrestrial ecosystems promoted the influence of autochthonous DOM sources. Still, tree leaves from overhanging canopies stood out as an important terrestrial DOM source, especially in sites where water residence time was high such as isolated pools and weirs. Degradation of leaf leachates was a relevant process in these sites, whereas autochthonous DOM and groundwater millennial DOM (> 1300 year B.P.) seemed to be degraded in running waters. Overall, our results highlight that the drought-induced hydrological disconnection entails a great spatial heterogeneity in the sources of DOM, which at the same time determines the different DOM pools that are respired in each environment along the river.
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| 50. |
- Castellá, Bruno Femenía, et al.
(författare)
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Commissioning and first light results of an L’-band vortex coronagraph with the Keck II adaptive optics NIRC2 science instrument
- 2016
-
Ingår i: Adaptive Optics Systems V. - : SPIE - International Society for Optical Engineering.
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Konferensbidrag (refereegranskat)abstract
- On March 2015 an L'-band vortex coronagraph based on an Annular Groove Phase Mask made up of a diamond sub-wavelength grating was installed on NIRC2 as a demonstration project. This vortex coronagraph operates in the L' band not only in order to take advantage from the favorable star/planet contrast ratio when observing beyond the K band, but also to exploit the fact that the Keck II Adaptive Optics (AO) system delivers nearly extreme adaptive optics image quality (Strehl ratios values near 90%) at 3.7 mu m. We describe the hardware installation of the vortex phase mask during a routine NIRC2 service mission. The success of the project depends on extensive software development which has allowed the achievement of exquisite real-time pointing control as well as further contrast improvements by using speckle nulling to mitigate the effect of static speckles. First light of the new coronagraphic mode was on June 2015 with already very good initial results. Subsequent commissioning nights were interlaced with science nights by members of the VORTEX team with their respective scientific programs. The new capability and excellent results so far have motivated the VORTEX team and the Keck Science Steering Committee (KSSC) to offer the new mode in shared risk mode for 2016B.
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