| 1. |
- Akiyama, Kazunori, et al.
(author)
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First Sagittarius A* Event Horizon Telescope Results. II. EHT and Multiwavelength Observations, Data Processing, and Calibration
- 2022
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In: Astrophysical Journal Letters. - : American Astronomical Society. - 2041-8213 .- 2041-8205. ; 930:2
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Journal article (peer-reviewed)abstract
- We present Event Horizon Telescope (EHT) 1.3 mm measurements of the radio source located at the position of the supermassive black hole Sagittarius A* (Sgr A*), collected during the 2017 April 5-11 campaign. The observations were carried out with eight facilities at six locations across the globe. Novel calibration methods are employed to account for Sgr A*'s flux variability. The majority of the 1.3 mm emission arises from horizon scales, where intrinsic structural source variability is detected on timescales of minutes to hours. The effects of interstellar scattering on the image and its variability are found to be subdominant to intrinsic source structure. The calibrated visibility amplitudes, particularly the locations of the visibility minima, are broadly consistent with a blurred ring with a diameter of similar to 50 mu as, as determined in later works in this series. Contemporaneous multiwavelength monitoring of Sgr A* was performed at 22, 43, and 86 GHz and at near-infrared and X-ray wavelengths. Several X-ray flares from Sgr A* are detected by Chandra, one at low significance jointly with Swift on 2017 April 7 and the other at higher significance jointly with NuSTAR on 2017 April 11. The brighter April 11 flare is not observed simultaneously by the EHT but is followed by a significant increase in millimeter flux variability immediately after the X-ray outburst, indicating a likely connection in the emission physics near the event horizon. We compare Sgr A*'s broadband flux during the EHT campaign to its historical spectral energy distribution and find that both the quiescent emission and flare emission are consistent with its long-term behavior.
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| 2. |
- Botvinik-Nezer, Rotem, et al.
(author)
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Variability in the analysis of a single neuroimaging dataset by many teams
- 2020
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In: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 582, s. 84-88
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Journal article (peer-reviewed)abstract
- Data analysis workflows in many scientific domains have become increasingly complex and flexible. Here we assess the effect of this flexibility on the results of functional magnetic resonance imaging by asking 70 independent teams to analyse the same dataset, testing the same 9 ex-ante hypotheses(1). The flexibility of analytical approaches is exemplified by the fact that no two teams chose identical workflows to analyse the data. This flexibility resulted in sizeable variation in the results of hypothesis tests, even for teams whose statistical maps were highly correlated at intermediate stages of the analysis pipeline. Variation in reported results was related to several aspects of analysis methodology. Notably, a meta-analytical approach that aggregated information across teams yielded a significant consensus in activated regions. Furthermore, prediction markets of researchers in the field revealed an overestimation of the likelihood of significant findings, even by researchers with direct knowledge of the dataset(2-5). Our findings show that analytical flexibility can have substantial effects on scientific conclusions, and identify factors that may be related to variability in the analysis of functional magnetic resonance imaging. The results emphasize the importance of validating and sharing complex analysis workflows, and demonstrate the need for performing and reporting multiple analyses of the same data. Potential approaches that could be used to mitigate issues related to analytical variability are discussed. The results obtained by seventy different teams analysing the same functional magnetic resonance imaging dataset show substantial variation, highlighting the influence of analytical choices and the importance of sharing workflows publicly and performing multiple analyses.
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| 3. |
- Villa, Luisa L., et al.
(author)
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Quadrivalent vaccine against human papillomavirus to prevent high-grade cervical lesions
- 2007
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In: New England Journal of Medicine. - 0028-4793 .- 1533-4406. ; 356:19, s. 1915-1927
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Journal article (peer-reviewed)abstract
- BACKGROUND: Human papillomavirus types 16 (HPV-16) and 18 (HPV-18) cause approximately 70% of cervical cancers worldwide. A phase 3 trial was conducted to evaluate a quadrivalent vaccine against HPV types 6, 11, 16, and 18 (HPV-6/11/16/18) for the prevention of high-grade cervical lesions associated with HPV-16 and HPV-18. METHODS: In this randomized, double-blind trial, we assigned 12,167 women between the ages of 15 and 26 years to receive three doses of either HPV-6/11/16/18 vaccine or placebo, administered at day 1, month 2, and month 6. The primary analysis was performed for a per-protocol susceptible population that included 5305 women in the vaccine group and 5260 in the placebo group who had no virologic evidence of infection with HPV-16 or HPV-18 through 1 month after the third dose (month 7). The primary composite end point was cervical intraepithelial neoplasia grade 2 or 3, adenocarcinoma in situ, or cervical cancer related to HPV-16 or HPV-18. RESULTS: Subjects were followed for an average of 3 years after receiving the first dose of vaccine or placebo. Vaccine efficacy for the prevention of the primary composite end point was 98% (95.89% confidence interval [CI], 86 to 100) in the per-protocol susceptible population and 44% (95% CI, 26 to 58) in an intention-to-treat population of all women who had undergone randomization (those with or without previous infection). The estimated vaccine efficacy against all high-grade cervical lesions, regardless of causal HPV type, in this intention-to-treat population was 17% (95% CI, 1 to 31). CONCLUSIONS: In young women who had not been previously infected with HPV-16 or HPV-18, those in the vaccine group had a significantly lower occurrence of high-grade cervical intraepithelial neoplasia related to HPV-16 or HPV-18 than did those in the placebo group.
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| 4. |
- Arayeshnia, Amir, et al.
(author)
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Miniaturized CPW-fed bowtie slot antenna for wearable biomedical applications
- 2020
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In: 2020 14th European Conference on Antennas and Propagation (EuCAP). - 9788831299008
-
Conference paper (peer-reviewed)abstract
- A miniaturized, low -profile, flexible, and wearable ultra-wideband antenna for biomedical applications is proposed. The antenna is designed to operate in wearable conditions with the presence of multilayer biological tissues. A meandering technique is employed to reduce the electrical size of the antenna. The operational band of the proposed antenna is 0.5-4.5 GHz, while its dimensions are as small as 21x19.25x0.025 mm3. The antenna is simulated using a commercial full-wave simulator (CST Microwave Studio), fabricated on Polyethylene terephthalate (PET), and tested in realistic scenarios. The simulation and measurement results are in good compliance with each other.
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| 5. |
- Asan, Noor Badariah, 1984-, et al.
(author)
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Effect of Thickness Inhomogeneity in Fat Tissue on In-Body Microwave Propagation
- 2018
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In: Proceedings of the 2018 IEEE/MTT-S International Microwave Biomedical Conference (IMBIOC). - Philadelphia, USA : IEEE. - 9781538659182 ; , s. 136-138
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Conference paper (peer-reviewed)abstract
- In recent studies, it has been found that fat tissue can be used as a microwave communication channel. In this article, the effect of thickness inhomogeneities in fat tissues on the performance of in-body microwave communication at 2.45 GHz is investigated using phantom models. We considered two models namely concave and convex geometrical fat distribution to account for the thickness inhomogeneities. The thickness of the fat tissue is varied from 5 mm to 45 mm and the Gap between the transmitter/receiver and the starting and ending of concavity/convexity is varied from 0 mm to 25 mm for a length of 100 mm to study the behavior in the microwave propagation. The phantoms of different geometries, concave and convex, are used in this work to validate the numerical studies. It was noticed that the convex model exhibited higher signal coupling by an amount of 1 dB (simulation) and 2 dB (measurement) compared to the concave model. From the study, it was observed that the signal transmission improves up to 30 mm thick fat and reaches a plateau when the thickness is increased further.
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| 6. |
- Asan, Noor Badariah, 1984-, et al.
(author)
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Effects of Blood Vessels on Fat Channel Microwave Communication
- 2018
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In: 2018 IEEE Conference on Antenna Measurements & Applications (CAMA). - : IEEE. - 9781538657959
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Conference paper (peer-reviewed)abstract
- This study aims to investigate the reliability of intra-body microwave propagation through the fat tissue in presence of blood vessels. Here, we consider three types of blood vessels with different sizes. We investigate the impact of the number of blood vessels and their alignment on the transmission of microwave signals through the fat channel. In our study, we employ two probes that act as a transmitter and a receiver. The probes are designed to operate at the Industrial, Scientific, and Medical radio band (2.45 GHz). For a channel length of 100 mm, our results indicate that the presence of the blood vessels may increase the channel path loss by similar to 1.5 dB and similar to 4.5 dB when the vessels are aligned and orthogonally aligned with the fat channel, respectively.
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| 7. |
- Asan, Noor Badariah, 1984-, et al.
(author)
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Fat-IntraBody Communication at 5.8 GHz : Verification of Dynamic Body Movement Effects using Computer Simulation and Experiments
- 2021
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In: IEEE Access. - : IEEE. - 2169-3536. ; 9, s. 48429-48445
-
Journal article (peer-reviewed)abstract
- This paper presents numerical modeling and experimental validation of the signal path loss at the 5.8 GHz Industrial, Scientific, and Medical (ISM) band, performed in the context of fat-intrabody communication (fat-IBC), a novel intrabody communication platform using the body-omnipresent fat tissue as the key wave-guiding medium. Such work extends our previous works at 2.0 and 2.4 GHz in the characterization of its performance in other useful frequency range. In addition, this paper also includes studies of both static and dynamic human body movements. In order to provide with a more comprehensive characterization of the communication performance at this frequency, this work focuses on investigating the path loss at different configurations of fat tissue thickness, antenna polarizations, and locations in the fat channel. We bring more realism to the experimental validation by using excised tissues from porcine cadaver as both their fat and muscle tissues have electromagnetic characteristics similar to those of human with respect to current state-of-art artificial phantom models. Moreover, for favorable signal excitation and reception in the fat-IBC model, we used topology optimized waveguide probes. These probes provide an almost flat response in the frequency range from 3.2 to 7.1 GHz which is higher than previous probes and improve the evaluation of the performance of the fat-IBC model. We also discuss various aspects of real-world scenarios by examining different models, particularly homogeneous multilayered skin, fat, and muscle tissue. To study the effect of dynamic body movements, we examine the impact of misalignment, both in space and in wave polarization, between implanted nodes. We show in particular that the use of fat-IBC techniques can be extended up in frequency to a broadband channel at 5.8 GHz.
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| 8. |
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| 9. |
- Brown, Darron R., et al.
(author)
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The Impact of Quadrivalent Human Papillomavirus (HPV; Types 6, 11, 16, and 18) L1 Virus-Like Particle Vaccine on Infection and Disease Due to Oncogenic Nonvaccine HPV Types in Generally HPV-Naive Women Aged 16-26 Years
- 2009
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In: Journal Of Infectious Diseases. - : Oxford University Press (OUP). - 0022-1899 .- 1537-6613. ; 199:7, s. 926-935
-
Conference paper (peer-reviewed)abstract
- Background. Human papillomavirus (HPV)-6/11/16/18 vaccine reduces the risk of HPV-6/11/16/18-related cervical intraepithelial neoplasia (CIN) 1-3 or adenocarcinoma in situ (AIS). Here, its impact on CIN1-3/AIS associated with nonvaccine oncogenic HPV types was evaluated. Methods. We enrolled 17,622 women aged 16-26 years. All underwent cervicovaginal sampling and Pap testing at regular intervals for up to 4 years. HPV genotying was performed for biopsy samples, and histological diagnoses were determined by a pathology panel. Analyses were conducted among subjects who were negative for 14 HPV types on day 1. Prespecified analyses included infection of >= 6 months' duration and CIN1-3/AIS due to the 2 and 5 most common HPV types in cervical cancer after HPV types 16 and 18, as well as all tested nonvaccine types. Results. Vaccination reduced the incidence of HPV-31/45 infection by 40.3% (95% confidence interval [CI], 13.9% to 59.0%) and of CIN1-3/AIS by 43.6% (95% CI, 12.9% to 64.1%), respectively. The reduction in HPV-31/33/45/52/58 infection and CIN1-3/AIS was 25.0% (95% CI, 5.0% to 40.9%) and 29.2% (95% CI, 8.3% to 45.5%), respectively. Efficacy for CIN2-3/AIS associated with the 10 nonvaccine HPV types was 32.5% (95% CI, 6.0% to 51.9%). Reductions were most notable for HPV-31. Conclusions. HPV-6/11/16/18 vaccine reduced the risk of CIN2-3/AIS associated with nonvaccine types responsible for similar to 20% of cervical cancers. The clinical benefit of cross-protection is not expected to be fully additive to the efficacy already observed against HPV-6/11/16/18-related disease, because women may have >1 CIN lesion, each associated with a different HPV type.
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| 10. |
- Calzone, Rocco, et al.
(author)
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Innovations in Biomedicine : Measuring Physiological Parameters Becomes As Simple As Applying A Plaster on the Body
- 2019
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In: Proceedings Of The 2019 International Conference On Electromagnetics In Advanced Applications (ICEAA). - New York : IEEE. - 9781728105635 ; , s. 1443-1446
-
Conference paper (peer-reviewed)abstract
- Electromagnetic applications play an essential role in medical research. As a response to the consistent increase in the number of people suffering from various diseases, the medical research is always looking for better diagnostic tools, expedited information transfer technologies, accurate prognosis devices, efficient patient management system and other alternative medicine strategies. In this context, the H2020 Project SINTEC proposes a soft intelligent epidermal communication platform where two main innovations are integrated: soft epidermal electronics and the intra-body communication based on fat tissue as a transmission channel. This proposed platform will host miniaturized, conformal and flexible sensing and data transfer technologies to enable real-time monitoring of certain vital parameters at any time (while doing sport, sleeping or watching television without having to go to a health specialized facility and/or using different devices such as a pulse oximetry, heart rate monitor and thermometer). As part of the phantom development, empirical models relating bioimpedance signals to other physiological signals (ECG, Sp02, Blood Pressure, etc.) is being studied and will be used to optimize phantom -based demonstrators as close as possible to human subjects. To this end, proper characterization of bioimpedance signals in different human subjects is crucial to devise such empirical models. This work presents preliminary results in four human volunteers, with different weight, gender and age, using two types of electrodes configurations. These results show that bioimpedance signals correlate well with volunteer's metadata as predicted by previous works. Finally, the communication through the FAT-channel and also comparisons with the traditional Freespace BLE (Bluetooth Low Energy) protocol will be demonstrated.
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| 11. |
- Dematties, Dario, et al.
(author)
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A Computational Theory for the Emergence of Grammatical Categories in Cortical Dynamics
- 2020
-
In: Frontiers in Neural Circuits. - : FRONTIERS MEDIA SA. - 1662-5110. ; 14
-
Journal article (peer-reviewed)abstract
- A general agreement in psycholinguistics claims that syntax and meaning are unified precisely and very quickly during online sentence processing. Although several theories have advanced arguments regarding the neurocomputational bases of this phenomenon, we argue that these theories could potentially benefit by including neurophysiological data concerning cortical dynamics constraints in brain tissue. In addition, some theories promote the integration of complex optimization methods in neural tissue. In this paper we attempt to fill these gaps introducing a computational model inspired in the dynamics of cortical tissue. In our modeling approach, proximal afferent dendrites produce stochastic cellular activations, while distal dendritic branches-on the other hand-contribute independently to somatic depolarization by means of dendritic spikes, and finally, prediction failures produce massive firing events preventing formation of sparse distributed representations. The model presented in this paper combines semantic and coarse-grained syntactic constraints for each word in a sentence context until grammatically related word function discrimination emerges spontaneously by the sole correlation of lexical information from different sources without applying complex optimization methods. By means of support vector machine techniques, we show that the sparse activation features returned by our approach are well suited-bootstrapping from the features returned by Word Embedding mechanisms-to accomplish grammatical function classification of individual words in a sentence. In this way we develop a biologically guided computational explanation for linguistically relevant unification processes in cortex which connects psycholinguistics to neurobiological accounts of language. We also claim that the computational hypotheses established in this research could foster future work on biologically-inspired learning algorithms for natural language processing applications.
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| 12. |
- Dematties, Dario, et al.
(author)
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Deep Learning of Nanopore Sensing Signals Using a Bi-Path Network
- 2021
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In: ACS Nano. - : American Chemical Society (ACS). - 1936-0851 .- 1936-086X. ; 15:9, s. 14419-14429
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Journal article (peer-reviewed)abstract
- Temporal changes in electrical resistance of a nanopore sensor caused by translocating target analytes are recorded as a sequence of pulses on current traces. Prevalent algorithms for feature extraction in pulse-like signals lack objectivity because empirical amplitude thresholds are user-defined to single out the pulses from the noisy background. Here, we use deep learning for feature extraction based on a bipath network (B-Net). After training, the B-Net acquires the prototypical pulses and the ability of both pulse recognition and feature extraction without a priori assigned parameters. The B-Net is evaluated on simulated data sets and further applied to experimental data of DNA and protein translocation. The B-Net results are characterized by small relative errors and stable trends. The B-Net is further shown capable of processing data with a signal-to-noise ratio equal to 1, an impossibility for threshold-based algorithms. The B-Net presents a generic architecture applicable to pulse-like signals beyond nanopore currents.
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| 13. |
- Ebrahimizadeh, Javad, et al.
(author)
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Electromagnetic Time-Reversal Technique for Monitoring Skull Healing Stages
- 2019
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In: 2019 13th European Conference On Antennas And Propagation (EuCAP). - : IEEE. - 9788890701887
-
Conference paper (peer-reviewed)abstract
- This paper provides a novel non-resonant spectroscopy technique for monitoring of the healing process in skull defects created in cranial surgery. Currently, there is not such a method and information on the healing process which is vital to avoid further complications and for a better understanding of the process. During the healing, which can take several months, the thickness and the permittivity of the skull varies. The proposed approach makes use of the approximated Dyadic Green's function integral equation for deriving the variations in permittivity of the skull. The scattered electric field from the defect is collected using Time-Reversal Array (TRA) in order to produce the Multi-StaticData Matrix (MDM). The singular value decomposition on the MDM matrix based on time reversal operator (TRO) decomposition (known under French acronym DORT), provides information of the permittivity of the defect. The problem of the sensing the defect response after the cranial surgery is formulated for multi-layer medium and it will be shown that the dominant singular values are corresponding to the permittivity of the defect. Finally, the veracity of the theory is clarified by conducting a numerical simulation for a planar multi-layer medium consisting of skin, skull brain and a defect embedded in the skull. We show that the dominant singular values corresponding to the defect permittivity vary significantly which conclude that the dominant singular value can be a good criterion for monitoring the skull healing stages.
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| 14. |
- Ebrahimizadeh, Javad, et al.
(author)
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Pathloss Calculation for Fat-Intra Body Communication Using Poynting Vector Theory
- 2020
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In: 2020 14th European Conference on Antennas and Propagation (EuCAP). - 9788831299008
-
Conference paper (peer-reviewed)abstract
- Recently, Fat-based Intra-Body Communication (Fat-IBC) has been proposed and studied in terms of its reliability in simulation and laboratory settings. We, in this work, try to address another important aspect of communication, namely pathloss, in the context of fat-IBC. The present paper provides numerical and experimental modeling of pathloss through the fat layer using the Poynting Vector theory and the Multi-layer dielectric Green's function (MGF). To calculate the pathloss based on Poynting vector theory, the electromagnetic field distribution through the involved media should be known. The present paper exploits the EM fields using MGF theory or commercial software CST Microwave Studio 2019. Finally, experimental measurement is done on ex-vivo tissue made of porcine skin, fat and muscle at the frequency range of 5 GHz - 6 GHz. The average measured pathloss is around 5.5 dB/cm which has good compliance with the theoretical Poynting vector pathloss estimation.
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| 15. |
- Ebrahimizadeh, Javad, et al.
(author)
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Time Reversal Microwave Imaging of Realistic Numerical Head Phantom for Bone Flap Healing Follow-up
- 2020
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In: 2020 IEEE MTT-S International Microwave Biomedical Conference (IMBioC). - 9781728158662 - 9781728158679
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Conference paper (peer-reviewed)abstract
- This paper presents the feasibility of using a microwave imaging system for monitoring bone mineralization progress overtime after craniotomy surgery. Any variation in the composition of the bone flap can be monitored as a variation in the intensity of the image. A simulation is conducted on a head structure derived from a numerical head phantom based on anatomically realistic MRI-derived FDTD models using commercial CST 2019 software. For simulation, a defect is provided in the skull layer surrounded by a 9-elements antenna. Applying Space-Frequency Time Reversal (TR) method, the image of defect is constructed for different permittivity of the defect ranging from 16 to 36. Results show that the image intensity at the defect location will decrease as the permittivity of the defect decreases.
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| 16. |
- Engstrand, Johan, et al.
(author)
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End-to-End Transmission of Physiological Data from Implanted Devices to a Cloud-Enabled Aggregator Using Fat Intra-Body Communication in a Live Porcine Model
- 2022
-
In: 2022 16TH EUROPEAN CONFERENCE ON ANTENNAS AND PROPAGATION (EUCAP). - : Institute of Electrical and Electronics Engineers (IEEE). - 9788831299046 - 9781665416047
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Conference paper (peer-reviewed)abstract
- This article presents, for the first time, the end-to-end transmission of physiological data from implanted antennas mimicking sensors to a cloud-enabled aggregator device using fat intra-body communication (fat-IBC). The experiment was performed on a live porcine model in full accordance with ethical standards. Measurement data from two different sensors were collected and sent through a fat-IBC network. The fat-IBC network consisted of three nodes, of which two used antennas implanted in the fat tissue of a live porcine model and one used an on-body antenna placed on the skin. The sensor data was forwarded via Bluetooth Low Energy to an Intel Health Application Platform device, which in turn forwarded the encrypted data to a web server. The experimental results demonstrate that the fat channel can be used in an end-to-end communication scheme, which could involve relaying of sensor data from an implanted device to an external web server.
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| 17. |
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| 18. |
- Gaffoglio, Rossella, et al.
(author)
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Compact Optimized Antenna Solution for Radiation Coupling Improvement in the Subcutaneous Fat Layer
- 2023
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In: 2023 17th European Conference on Antennas and Propagation, EuCAP. - : IEEE. - 9788831299077 - 9781665475419
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Conference paper (peer-reviewed)abstract
- Fat intra-body communication (Fat-IBC) aims at confining microwave propagation to the subcutaneous adipose tissue layer for the creation of a safe high-speed, high-bandwidth data transmission link through the body. This technique can be exploited to connect implantable medical devices and to implement a two-way transmission of recorded neural data and sensory stimulation signals between brain and robotic limbs. In this paper, a compact printed antenna solution for non-invasive tests of the Fat-IBC on non-human primates (NHPs) is proposed. This antenna is a printed monopole with a triangular radiating element embedded into a rigid brick, properly optimized to favor the radiation coupling in a 5mm-thick fat layer and minimize the signal propagation through the air. A promising wave coupling in the adipose tissue is achieved and a compact realizable layout is finalized for future prototyping and testing.
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| 19. |
- Giannetta, H. M. R., et al.
(author)
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Study of the electrical parameters drift due to mechanical stress in coupled conductors path on flexible polymeric substrate
- 2022
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In: 2022 Argentine Conference on Electronics (CAE). - : Institute of Electrical and Electronics Engineers (IEEE). - 9781728173351 - 9781728192659 ; , s. 37-40
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Conference paper (peer-reviewed)abstract
- In this work, the behavior of the drift in electrical impedance values of a coupled device constituting a flat rectangular inductor surrounded by a coupled antenna while subjected to mechanical stresses of over 10,000 bending-stretching cycles has been studied. It has shown correlation with mechanical aging and also is influenced by temperature variations on the device surface. The impact of the mechanical stress was studied separately for the bending-stretching and relaxation phases, considering in both cases the effect of temperature changes and mechanical stress, in order to obtain an adjustment equation for the measured experimental data.. From the fit, it was observed that when using an exponential function for the drift effect due to mechanical stress, the experimental curve was fitted with R-2=0.91 for the bending-stretching phase and R-2=0.79 for the relaxation phase.
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| 20. |
- Joseph, Laya, et al.
(author)
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Non-Invasive Transmission Based Tumor Detection Using Anthropomorphic Breast Phantom at 2.45 GHz
- 2020
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In: 2020 14th European Conference on Antennas and Propagation (EuCAP). - 9788831299008 - 9781728137124
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Conference paper (peer-reviewed)abstract
- Breast cancer detection using microwave imaging techniques is a widely explored research field. In this paper, we propose the development of a heterogeneous, semi-solid and stable breast phantom with skin, fat, muscle and spherical tumor inclusion models and a transmission-based sensing method for non-invasive tumor detection. The proposed breast phantom emulates the anatomical, physical and dielectric properties as human breast tissues. The dielectric properties of the breast phantom is measured using open ended coaxial slim probe from Keysight Technologies and is compared with the Nello Carrara Institute of Applied Physics (IFAC) data in the frequency range of 500 MHz - 20GHz. The S 21 scattering parameter is measured and studied for a normal breast phantom and the breast phantom with tumor inclusion models representing its different growth stages using Topology Optimized Planar Antenna (TOPA) based probe. The measurements are done by using FieldFox microwave analyzer (N9918A) by Keysight Technologies. The study shows S 21 amplitude variation of 2 - 12 dB for tumor inclusion models of size ranging from 4mm - 16mm diameter with respect to normal breast model. This study indicates that with further development, transmission-based methods can be used for preliminary screening of breast tumor.
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| 21. |
- Joura, Elmar A., et al.
(author)
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HPV antibody levels and clinical efficacy following administration of a prophylactic quadrivalent HPV vaccine
- 2008
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In: Vaccine. - : Elsevier BV. - 1873-2518 .- 0264-410X. ; 26:52, s. 6844-6851
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Journal article (peer-reviewed)abstract
- The efficacy of the quadrivalent Human Papillomavirus (HPV) vaccine is thought to be mediated by humoral immunity. We evaluated the correlation between quadrivalent HPV vaccine-induced serum anti-HPV responses and efficacy. 17,622 women were vaccinated at day 1, and months 2 and 6. At day I and at 6-12 months intervals for up to 48 months, subjects underwent Papanicolaou and genital HPV testing. No immune correlate of protection could be found due to low number of cases. Although 40% of vaccine subjects were anti-HPV 18 seronegative at end-of-study, efficacy against HPV 18-related disease remained high (98.4%; 95% CI: 90.5-100.0) despite high attack rates in the placebo group. These results suggest vaccine-induced protection via immune memory, or lower than detectable HPV 18 antibody titers. (C) 2008 Elsevier Ltd. All rights reserved.
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| 22. |
- Kommata, Varvara, et al.
(author)
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QRS dispersion detected in ARVC patients and healthy gene carriers using 252-leads body surface mapping : an explorative study of a potential diagnostic tool for arrhythmogenic right ventricular cardiomyopathy
- 2021
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In: Pacing and Clinical Electrophysiology. - : Wiley. - 0147-8389 .- 1540-8159. ; 44:8, s. 1355-1364
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Journal article (peer-reviewed)abstract
- BACKGROUND: The diagnosis of ARVC remains complex requiring both imaging and electrocardiographic (ECG) techniques. The purpose was therefore to investigate whether QRS dispersion assessed by body surface mapping (BSM) could be used to detect early signs of ARVC, particularly in gene carriers.METHODS: ARVC patients, gene carriers without a history of arrhythmias or structural cardiac changes and healthy controls underwent 12-lead resting ECG, signal-averaged ECG, echocardiographic examination, 24-hours Holter monitoring, and BSM with electrocardiographic imaging. All 252-leads BSM recordings and 12-leads ECG recordings were manually analyzed for QRS durations and QRS dispersion.RESULTS: Eight controls, 12 ARVC patients with definite ARVC and 20 healthy gene carriers were included. The ECG-QRS dispersion was significantly greater in ARVC patients (42 vs. 25 ms, p < .05), but failed to fully differentiate them from controls. The BSM-derived QRS dispersion was also significantly greater in ARVC patients versus controls (65 vs. 29 ms, p < .05) and distinguished 11/12 cases from controls using the cut-off 40msec. The BSM derived QRS dispersion was abnormal (> 40 ms) in 4/20 healthy gene carriers without signs of ARVC, which may indicate early depolarization changes.CONCLUSIONS: QRS dispersion, when assessed by BSM versus 12-lead ECG, seem to better distinguish ARVC patients from controls, and could potentially be used to detect early ARVC in gene carriers. Further studies are required to confirm the value of BSM-QRS dispersion in this respect.
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| 23. |
- Kommata, Varvara, et al.
(author)
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The repolarization pattern of ARVC patients, healthy gene carriers and controls as analyzed with a 252-leads Body Surface Mapping Vest
- 2020
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In: European Heart Journal. - : Oxford University Press (OUP). - 0195-668X .- 1522-9645. ; 41:Supplement_2
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Journal article (peer-reviewed)abstract
- Background: Repolarization abnormalities have a central role on the diagnosis of ARVC according to recent HRS consensus document from 2019 stating that T wave inversion in the right precordial leads is a major criteria if it appears in V1-V3 or a minor criteria if it appears in only V1-V2.Purpose: The aim of our study was to investigate whether repolarization patterns as recorded by a Body Surface Mapping (BSM) system consisting of a vest with 252 ECG leads, could differentiate ARVC patients and even gene carriers from normal individuals. Our hypothesis is that the method can potentially identify repolarization disturbances earlier or better than conventional 12-lead ECG.Method: 12 definite ARVC patients, 20 healthy gene carriers and 8 family members who tested negative for the family mutation (controls) were included. All patients underwent 12-lead ECG, including right precordial leads (V4R) and BSM recordings. Repolarization (T-wave polarity and concordance with QRS complex vector) was analyzed qualitatively in all BSM recordings, the results of which were displayed on a color code map (fig.1).Results: The mean age was 49.6, 43.6 and 38.8 years in ARVC patients, healthy gene carriers and controls, respectively. The number of males in the three groups were 8/12, 8/20 and 5/8, respectively.All 8 controls had similar repolarization patterns with negative and concordant T waves on the right back panel, and T waves that successively changed from negative concordant (green) to positive disconcordant (red) and finally positive concordant (blue) on the left front panel (pattern 1). All 12 ARVC patients had different repolarization patterns as compared to the controls. Two of these patients had no apparent repolarization changes on conventional 12 lead ECG. The pattern type 2 repolarization, as defined by same pattern as the controls at the right back panel but different pattern at the front left panel was seen in 3/12 ARVC patients. The remaining 9 ARVC patients had different repolarization patterns both on the front and on the back panel (pattern 3). Among gene carriers, 15 had a normal repolarization pattern (pattern 1) and 5 demonstrated an abnormal repolarization pattern (4 had pattern type 2 and one pattern 3) despite normal surface ECG.Conclusions: Using BSM recordings, abnormal repolarization patterns can be detected in all ARVC patients, even in those without repolarization changes on conventional surface ECG. The observation that 25% of gene carriers had divergent repolarization patterns, may indicate an early stage of the disease, and be used as an early diagnostic marker of the disease. Further and larger studies are warranted to confirm these observations.
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| 24. |
- Madannejad, Alireza, et al.
(author)
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Reflectometry Enhancement by Saline Injection in Microwave-based Skin Burn Injury Diagnosis
- 2020
-
In: 2020 14th European Conference on Antennas and Propagation (EuCAP). - 9788831299008
-
Conference paper (peer-reviewed)abstract
- This paper provides a novel solution for increasing the difference between the contrast of permittivity of normal skin and burnt skin using injected saline. The paper makes use of injecting saline water into healthy tissue surrounding the burnt part to increase the conductivity contrast of the healthy tissue compared to the burnt area. After 5 minutes passed by injecting the saline, it will he distributed through the normal tissues while the burnt tissues are not able to absorb the saline. Therefore, the level of permittivity contrast between the healthy tissue and burnt tissue increase drastically which is useful for microwave noninvasive diagnosis.
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| 25. |
- Mandal, Bappaditya, et al.
(author)
-
A Low Profile Button Antenna with Back Radiation Reduced By FSS
- 2020
-
In: 2020 14th European Conference on Antennas and Propagation (EuCAP). - 9788831299008 - 9781728137124
-
Conference paper (peer-reviewed)abstract
- In this article, a button antenna with a reflective frequency selective surface(FSS) is proposed to reduce its back radiation. The proposed antenna is low in profile, circularly polarized and designed for Wi-Fi and WLAN applications. The radiating element is made of copper sheet, while a transparent acrylic fibre sheet is used as a substrate. The antenna is fed by a coaxial line, and the FSS layer is designed on jeans material. The patch type FSS with split ring shape has also been designed to operate in the Wi-Fi and WLAN frequency hand (5.250-5.850 GHz) with the centre frequency of 5.51 GHz. The FSS reduces hack radiation of the antenna by 4 dB. The antenna with FSS is fabricated, and a measured gain of 2.9dBi is obtained that matches well with the theoretical value. The antenna is miniaturized by around 61.15% by the slits. To achieve circular polarization characteristic Defected Ground Structure (DGS) slots etched at the ground plane of the triangular patch. The measured impedance bandwidth is 190MHz, and the 3dB axial-ratio (AR) bandwidth is 160MHz, respectively.
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| 26. |
- Mandal, Bappaditya, et al.
(author)
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Low Profile Implantable Antenna for Fat Intra-Body Communication
- 2020
-
In: 2020 14th European Conference on Antennas and Propagation (EuCAP). - 9788831299008 - 9781728137124
-
Conference paper (peer-reviewed)abstract
- A flexible low profile biocompatible implantable antenna for fat intra-body communication is presented. This article gives an idea of fat channel communication at different distances. The antenna is designed on 0.25 mm thick low loss taconic material. The antenna is covered by 0.1 mm thick PDMS (Polydimethylsiloxane) to ensure biocompatibility with human tissue. A coplanar wave (CPW) microstrip line is used to feed the antenna. This antenna has been optimized to operate at the 2.4 GHz hand frequency in the human three -layer tissue model The simulation, as well as measurement, were done at a minimum distance of 10 mm, and the maximum distance of 70mm between of two implantable antennas. The measured path loss of the fat channel by using the proposed implantable antenna is estimated to be almost 2.5 dB per centimetre. The measured bandwidth of the proposed antenna found to be 660 MHz.
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| 27. |
- Mathur, Parul, et al.
(author)
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An Efficient Method for Computing the Interaction of Open Ended Circular Waveguide with a Layered Media
- 2018
-
In: Progress In Electromagnetics Research Letters. - : E M W PUBLISHING. - 1937-6480. ; 76, s. 55-61
-
Journal article (peer-reviewed)abstract
- This article presents a new method for studying the near-field electromagnetic interaction between a dielectric filled open ended circular waveguide (OECW) and a layered dielectric structure. The proposed model is based on plane wave spectrum theory using a novel and computationally efficient two step integration method. The first integral, involving multiple singularities in the integration path, is efficiently solved using a deformed elliptical integration path which encircles the singularities of the integral. The infinite domain tail integral involving the slowly converging integrand is further solved using an efficient trigonometric transformation. The proposed OECW based method is capable of determining the unknown material properties of any layered dielectric medium, and hence finds application in nondestructive evaluation of materials.
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| 28. |
- Mathur, Parul, et al.
(author)
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NDECOAX : A software package for nondestructive evaluation of stratified dielectric media
- 2019
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In: SoftwareX. - : Elsevier. - 2352-7110. ; 9, s. 187-192
-
Journal article (peer-reviewed)abstract
- This article presents a software package based on the C++ language for accurate computation of material properties of a stratified media using an open ended coaxial probe (OECP). Since OECP is one of the most commonly used sensors for evaluation of materials today, the program developed can be customized for real time nondestructive evaluation of materials. The main contribution of this article is a computationally efficient software for solving an infinite domain integral with multiple singularities based on plane wave spectrum theory. The computed results for aperture admittance of the coaxial probe using the developed software show good agreement with both measurements and results from a commercial solver using the finite element method (FEM). It is also proved that, the execution time per frequency point of the developed code is much faster than FEM. (C) 2019 The Authors. Published by Elsevier B.V.
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| 29. |
- Mattsson, Viktor
(author)
-
Data-Driven Methods for Microwave Sensor Devices in Musculoskeletal Diagnostics
- 2024
-
Doctoral thesis (other academic/artistic)abstract
- Microwave sensors can be used within medicine as they use non-ionizing radiation, are often low cost, and can be designed for a specific purpose. The application of microwave sensors for diagnostics and monitoring can be improved using appropriate data analysis. The multi-layered structure of the human body makes the measurements on people complex. A tremendous effort is required to create an analytical model of the body. In this context a data-driven approach, building a model that learns from previous measurements, is more suitable to analyze the data. This thesis aims to address statistical and data-driven approaches based on microwave sensor data for biomedical applications.A significant part of this thesis deals with microwave sensors for assessing muscle quality. It details the progress from initial clinical campaign to the creation of a machine learning algorithm to assess the local body composition. Such a device would be suitable for screening age-related muscle disorders like sarcopenia and muscle atrophy. Statistical analysis following the initial clinical campaign revealed no significant differences in the microwave data. Therefore, new sensor designs were evaluated. The most promising sensor was used in a small clinical campaign where it was able to detect a change in muscle size for one patient with multiple measurements over time. Successive measurements followed on tissue emulating phantoms and volunteers. For data analysis a machine learning algorithm was designed to predict the skin, fat, and muscle properties. This changes the aim from assessing muscle quality to assessing local body composition. For phantom data the algorithm was accurate for skin and fat and for volunteer data for fat and muscle. Crucially, the algorithm also performed better with more data available, meaning that results should improve if more data is collected.Microwave sensors have also been employed to assess bone. The first of two applications was to monitor the bone healing progression post surgery treating craniosynostosis. No substantial conclusions could be drawn from the statistical analysis most likely due to measurement uncertainties. The second application used a purpose-built setup for controlled measurements in ex vivo bone samples submerged in liquid, to simulate an in vivo environment. The purpose was to estimate the dielectric properties of bone. The derived bone properties were lower than expected, probably due to air trapped inside the sample.
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| 30. |
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| 31. |
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| 32. |
- Mattsson, Viktor, et al.
(author)
-
Machine Learning Powered Microwave Device for Local Body Composition Assessment
- 2023
-
In: IEEE Sensors Journal. - 1530-437X .- 1558-1748. ; , s. 1-1
-
Journal article (peer-reviewed)abstract
- In this paper a standalone microwave device is evaluated for its ability to assess local body composition with the ultimate goal to assess muscle quality. Data have been collected from volunteers who were measured on their thigh using the microwave device and ultrasound. A machine learning algorithm with three stages is designed that utilizes the stacked nature of the tissues in the thigh to predict skin and fat thickness and the cross-sectional area of the rectus femoris muscle. The input to the algorithm is the signal response from the microwave sensor and also the prediction from the previous layers. The ultrasound measurements are used as the ground truth labels for each tissue to train the machine learning models. The measurements were performed with two sensors, where usage of the combined data from both sensors produced the best results for fat and muscle, 0.57 and 0.63 in R 2 score, respectively. In the drop analysis, a step where a select proportion of the data is temporarily removed, the identified models showed increased scores with a larger amount of data available indicating the learning of the models improves with more data. Although the results are encouraging more data is ultimately needed to further study the algorithm.
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| 33. |
- Mattsson, Viktor, et al.
(author)
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MAS : Standalone Microwave Resonator to Assess Muscle Quality
- 2021
-
In: Sensors. - : MDPI. - 1424-8220. ; 21:16
-
Journal article (peer-reviewed)abstract
- Microwave-based sensing for tissue analysis is recently gaining interest due to advantages such as non-ionizing radiation and non-invasiveness. We have developed a set of transmission sensors for microwave-based real-time sensing to quantify muscle mass and quality. In connection, we verified the sensors by 3D simulations, tested them in a laboratory on a homogeneous three-layer tissue model, and collected pilot clinical data in 20 patients and 25 healthy volunteers. This report focuses on initial sensor designs for the Muscle Analyzer System (MAS), their simulation, laboratory trials and clinical trials followed by developing three new sensors and their performance comparison. In the clinical studies, correlation studies were done to compare MAS performance with other clinical standards, specifically the skeletal muscle index, for muscle mass quantification. The results showed limited signal penetration depth for the Split Ring Resonator (SRR) sensor. New sensors were designed incorporating Substrate Integrated Waveguides (SIW) and a bandstop filter to overcome this problem. The sensors were validated through 3D simulations in which they showed increased penetration depth through tissue when compared to the SRR. The second-generation sensors offer higher penetration depth which will improve clinical data collection and validation. The bandstop filter is fabricated and studied in a group of volunteers, showing more reliable data that warrants further continuation of this development.
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| 34. |
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| 35. |
- Mattsson, Viktor, et al.
(author)
-
Muscle Analyzer System : Exploring Correlation Between Novel Microwave Resonator and Ultrasound-based Tissue Information in the Thigh
- 2022
-
In: 2022 16TH EUROPEAN CONFERENCE ON ANTENNAS AND PROPAGATION (EUCAP). - : Institute of Electrical and Electronics Engineers (IEEE). - 9788831299046
-
Conference paper (peer-reviewed)abstract
- A microwave sensor to safely measure quality of muscle tissue for diagnosis and screening of diseases and medical conditions characterized by fat infiltration in muscle is presented. Fat infiltration in muscle may be seen by a lower dielectric constant of muscle at microwave frequencies corresponding to the large contrast between fat and muscle tissues. A planar resonator based on a bandstop filter and optimized to noninvasively interrogate muscle in the thigh on tissue quality is proposed. Currently, a study based on clinical trials is carried out, and, here, we present a preliminary correlation between skin and fat thicknesses and rectus femoris cross sectional area (CSA) measured with ultrasound and the proposed sensor's resonance frequency. CST simulations based on the ultrasound information guide the analysis. We see that although there are signs of a potential correlation between CSA and resonance, skin and fat variability is still an issue to overcome.
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| 36. |
- Mattsson, Viktor, et al.
(author)
-
Neural Network Approach for Dielectric Characterization of Tissues in Microwave Frequencies using Coplanar Waveguide Transmission
- 2020
-
In: 2020 14th European Conference on Antennas and Propagation (EuCAP). - 9788831299008
-
Conference paper (peer-reviewed)abstract
- This paper presents an extension to previous work, using neural networks to characterize materials in microwave frequencies, to extend the applicability of a deep learning model to be able to characterize the dielectric properties of biological tissues. A neural network model using convolutional and fully connected layers is designed to predict the permittivity and loss tangent using the scattering parameters from a coplanar waveguide transmission sensor. Simulated data from the sensor provide a large dataset, with a wide range of values for the permittivity and loss tangent, which is used to train and test the model. The trained network is validated by predicting the output parameters on the test set. Compared with previous work, by using convolutional layers the applicable parameter space is vastly extended while keeping satisfying levels of accuracy. A complete system with a trained network is proposed to be used in a lab or in clinics.
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| 37. |
- Mohd Shah, Syaiful Redzwan, 1984-, et al.
(author)
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Microwave-Sensor-Based Clinical Measurements for Monitoring Post-Craniotomy Bone Development in Pediatric Craniosynostosis Patients
-
Journal article (peer-reviewed)abstract
- The bone density analysis system is a new method to analyze the amount of bone healed in cranial vault defects. Craniotomy creates such defects to treat pediatric patients with craniosynostosis. This method uses the variations in the resonance of a microwave sensor attached to the area under test in the patient. Data were collected from infants treated for craniosynostosis through craniotomy surgery in clinical trials. The data, which consist of resonance parameters (frequency, amplitude, and Q-factor) is collected using a microwave-based biomedical sensor. This sensor could detect changes in the resonance as changes in the permittivity of the various tissues at the ISM band. By observing differences between a reference and target defect points, bone healing over time could be accessed. In this paper, we analyze the validity of a proposed Computational Simulation Technology (CST) based numerical model for the sensor and extend the clinical data analysis from previous works with our bone density analysis system. The validity of the model is analyzed by comparing its outcomes to available measurements from numerical simulations, phantoms mimicking living tissues and clinical trial. In the data analysis, a hypothesis is formulated and tested regarding the healing over time. By deriving a set of parameters for each collected dataset in the clinical trials, a distinct pattern was found which shows visible changes such as edema and tissue thickening over the course of the healing process with this technique. Moreover, we manage to distinguish significant differences between the reference and defect points after the craniosynostosis surgery.
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| 38. |
- Muñoz, Nubia, et al.
(author)
-
Impact of Human Papillomavirus (HPV)-6/11/16/18 Vaccine on All HPV-Associated Genital Diseases in Young Women.
- 2010
-
In: Journal of the National Cancer Institute. - : Oxford University Press (OUP). - 1460-2105 .- 0027-8874. ; 102, s. 325-339
-
Journal article (peer-reviewed)abstract
- Background The impact of the prophylactic vaccine against human papillomavirus (HPV) types 6, 11, 16, and 18 (HPV6/11/16/18) on all HPV-associated genital disease was investigated in a population that approximates sexually naive women in that they were "negative to 14 HPV types" and in a mixed population of HPV-exposed and -unexposed women (intention-to-treat group). Methods This analysis studied 17 622 women aged 15-26 years who were enrolled in one of two randomized, placebo-controlled, efficacy trials for the HPV6/11/16/18 vaccine (first patient on December 28, 2001, and studies completed July 31, 2007). Vaccine or placebo was given at day 1, month 2, and month 6. All women underwent cervicovaginal sampling and Papanicolaou (Pap) testing at day 1 and every 6-12 months thereafter. Outcomes were any cervical intraepithelial neoplasia; any external anogenital and vaginal lesions; Pap test abnormalities; and procedures such as colposcopy and definitive therapy. Absolute rates are expressed as women with endpoint per 100 person-years at risk. Results The average follow-up was 3.6 years (maximum of 4.9 years). In the population that was negative to 14 HPV types, vaccination was up to 100% effective in reducing the risk of HPV16/18-related high-grade cervical, vulvar, and vaginal lesions and of HPV6/11-related genital warts. In the intention-to-treat group, vaccination also statistically significantly reduced the risk of any high-grade cervical lesions (19.0% reduction; rate vaccine = 1.43, rate placebo = 1.76, difference = 0.33, 95% confidence interval [CI] = 0.13 to 0.54), vulvar and vaginal lesions (50.7% reduction; rate vaccine = 0.10, rate placebo = 0.20, difference = 0.10, 95% CI = 0.04 to 0.16), genital warts (62.0% reduction; rate vaccine = 0.44, rate placebo = 1.17, difference = 0.72, 95% CI = 0.58 to 0.87), Pap abnormalities (11.3% reduction; rate vaccine = 10.36, rate placebo = 11.68, difference = 1.32, 95% CI = 0.74 to 1.90), and cervical definitive therapy (23.0% reduction; rate vaccine = 1.97, rate placebo = 2.56, difference = 0.59, 95% CI = 0.35 to 0.83), irrespective of causal HPV type. Conclusions High-coverage HPV vaccination programs among adolescents and young women may result in a rapid reduction of genital warts, cervical cytological abnormalities, and diagnostic and therapeutic procedures. In the longer term, substantial reductions in the rates of cervical, vulvar, and vaginal cancers may follow.
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| 39. |
- Perez, Mauricio D., et al.
(author)
-
Head-compliant microstrip split ring resonator for non-invasive healing monitoring after craniosynostosis-based surgery
- 2020
-
In: HEALTHCARE TECHNOLOGY LETTERS. - : INST ENGINEERING TECHNOLOGY-IET. - 2053-3713. ; 7:1, s. 29-34
-
Journal article (peer-reviewed)abstract
- A soft and highly directive, proximity-coupled split-ring resonator fabricated with a liquid alloy, copper and polydimethylsiloxane (PDMS) is presented. The same was designed for sensing osteogenesis of calvarial bone. As dielectric properties of bone grafts in ossifying calvarial defects should change during the osteogenesis process, devices like this could monitor the gradual transformation of the defect into bone by differentiating changes in the dielectric properties as shifts in the resonance frequency. Computational Software Technology (CST) Microwave Studio (R)-based simulation results on computational head models were in good agreement with laboratory results on head phantom models, which also included the comparison with an in-vivo measurement on the human head. A discussion based on an inductive reasoning regarding dynamics' considerations is provided as well. Since the skin elasticity of newborn children is high, stretching and crumpling could be significant. In addition, due to typical head curvatures in newborn children, bending should not be a significant issue, and can provide higher energy focus in the defect area and improve conformability. The present concept could support the development of soft, cheap and portable follow-up monitoring systems to use in outpatient hospital and home care settings for post-operative monitoring of bone healing after reconstructive surgical procedures.
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| 40. |
- Perez, Mauricio D., et al.
(author)
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Microwave Sensors for New Approach in Monitoring Hip Fracture Healing
- 2017
-
In: 2017 11th European Conference On Antennas And Propagation (EUCAP). - : IEEE. - 9788890701870 ; , s. 1838-1842
-
Conference paper (peer-reviewed)abstract
- Cyber-Physical System (CPS) applications in lower-extremity bony-fracture rehabilitation systems require real-time biophysical data. Emerging and interesting solutions are microwave approaches that provide good contrast between hard and soft tissues and between local anomalies inside tissues. Preliminarily some contacting non-invasive planar methods have been investigated in their feasibility of detecting human tissues variations with promising results. In this work we introduce two new microwave planar sensors for a new approach of hip fracture healing follow-up tool. They are designed for improved resolution and penetration at frequencies between 1 to 3 GHz in detecting variations in bone, muscle or fat tissues that are expected during a rehabilitation process. The resonant devices are optimized using Frequency Domain Reflectometry and CST (R) environment and validated using clinical trials with volunteers. The new approach is validated using clinical trials with volunteers and patients. These outcomes further emphasize the feasibility of devising systems for fracture rehabilitation.
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| 41. |
- Perez, Mauricio D., et al.
(author)
-
New Approach for Clinical Data Analysis of Microwave Sensor Based Bone Healing Monitoring System in Craniosynostosis Treated Pediatric Patients
- 2018
-
In: 2018 IEEE Conference On Antenna Measurements & Applications (CAMA). - : IEEE. - 9781538657959
-
Conference paper (peer-reviewed)abstract
- In the BDAS project one of the goals is to provide a solution to the monitoring bone healing issue complementing current techniques. Data have been collected in clinical trials from infants treated for Craniosynostosis by a craniotomy surgery. The data are collected with a biomedical sensor based in microwave technology. This sensor could be able to sense changes in the composition of the different tissues in the upper-hemisphere of the head by noticing a difference in the propagation of the microwaves, as the bone injury from the craniotomy heals over time. In this thesis, we analyse the clinical data in BDAS project incorporating new approaches with respect to previous analysis methods. These new approaches could give new insight into the proposed solution, but more analysis need to be done.
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| 42. |
- Perez, Mauricio D., et al.
(author)
-
Phantom-based evaluation of a planar microwave sensor for non-invasive intracranial pressure monitoring
- 2023
-
In: 2023 IEEE MTT-S International Microwave Biomedical Conference, IMBioC. - : IEEE. - 9781665492171 - 9781665492188 ; , s. 1-3
-
Conference paper (peer-reviewed)abstract
- Intracranial pressure (ICP) measurements are essential to improve current clinical decision schemes in different scenarios: hospital, home, sports field, military field, etc. ICP is fundamental for understanding cerebrospinal fluid (CSF) mechanics and modelling better physiological conditions. Nowadays, several studies have focused on developing non-invasive ICP monitoring methods (nICP) based on different sensing modalities with advantages and disadvantages. Some works have focused on microwave-based sensing; among them is the application of NASA SansEC spectroscopy technology. This work extends previous results on this technology to nICP. Notably, in a simple phantom-based experiment and with a square spiral planar resonator sensor, pressure values up to 48 mmHg could be achievable. The phantom-based experiment consists of a large column tank gradually filled with a liquid that mimics the cerebrospinal fluid (CSF) based on data from the Italian database IFAC. Microwave-based methods for non-invasive intracranial pressure monitoring could be instrumental as tools that can be easily embedded and worn and give indications of brain health to trigger proper care in the future.
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| 43. |
- Rangaiah, Pramod, et al.
(author)
-
92 Mb/s Fat-Intrabody Communication (Fat-IBC) With Low-Cost WLAN Hardware
- 2024
-
In: IEEE Transactions on Biomedical Engineering. - : Institute of Electrical and Electronics Engineers (IEEE). - 0018-9294 .- 1558-2531. ; 71:1, s. 89-96
-
Journal article (peer-reviewed)abstract
- The human subcutaneous fat layer, skin and muscle together act as a waveguide for microwave transmissions and provide a low-loss communication medium for implantable and wearable body area networks (BAN). In this work, fat-intrabody communication (Fat-IBC) as a human body-centric wireless communication link is explored. To reach a target 64 Mb/s inbody communication, wireless LAN in the 2.4 GHz band was tested using low-cost Raspberry Pi single-board computers. The link was characterized using scattering parameters, bit error rate (BER) for different modulation schemes, and IEEE 802.11n wireless communication using inbody (implanted) and onbody (on the skin) antenna combinations. The human body was emulated by phantoms of different lengths. All measurements were done in a shielded chamber to isolate the phantoms from external interference and to suppress unwanted transmission paths. The BER measurements show that, except when using dual on-body antennas with longer phantoms, the Fat-IBC link is very linear and can handle modulations as complex as 512-QAM without any significant degradation of the BER. For all antenna combinations and phantoms lengths, link speeds of 92 Mb/s were achieved using 40 MHz bandwidth provided by the IEEE 802.11n standard in the 2.4 GHz band. This speed is most likely limited by the used radio circuits, not the Fat-IBC link. The results show that Fat-IBC, using low-cost off-the-shelf hardware and established IEEE 802.11 wireless communication, can achieve high-speed data communication within the body. The obtained data rate is among the fastest measured with intrabody communication.
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| 44. |
- Rangaiah, Pramod, et al.
(author)
-
Dielectric Characterization and Statistical Analysis of Ex-Vivo Burnt Human Skin Samples for Microwave Sensor Development
- 2023
-
In: IEEE Access. - : IEEE. - 2169-3536. ; 11, s. 4359-4372
-
Journal article (peer-reviewed)abstract
- The dielectric properties of skin tissues in relation to different degrees of burn are a necessary prerequisite for designing non-invasive microwave sensing modalities. Due to the difficulties in obtaining human tissue samples, such databases are largely unavailable. To bridge the knowledge gap in this field, we attempt to create a dielectric database of various burn-degree skin samples and their statistical analysis in this work. This research is part of the European "Senseburn " project, which aims to create a non-invasive diagnostic tool that can measure the severity and depth of burns on humans in a clinical setting. In this work, several ex-vivo burnt samples were collected from the Uppsala University Hospital (Akademiska sjukhuset, Sweden). Out of that, eight samples with different degrees of burns in various human body locations were selected for the analysis. The dielectric characterization of the categorized samples was done using an Keysight N1501A dielectric open-end co-axial probe Kit. The dielectric characterization was made from 500 MHz to 10 GHz with 1001 points. The measurement was made systematically, and the clinician feedback forms were gathered and analyzed throughout the process. The measurement data followed the FASTCLUS procedure, which was initially analyzed using density plot, convergence, and cubic clustering criteria. For the statistical analysis, 11 frequency points were considered for eight samples. The results of the fundamental statistical analysis using the FASTCLUS procedure resulted in 88 data sets. Later, data sets were analyzed in sample-wise clusters. Every sample was made with two clusters, i.e., cluster 1, which consisted of healthy sectors, and cluster 2, which consisted of burnt sectors. We made the linear approximations for the sample-wise clusters and found the constant real permittivity difference. Furthermore, we found a pattern in the constant real permittivity differences of every sample that is proportional to the burn degrees. This information is needed in order to identify optimization parameters, i.e., the sensitivity with respect to dielectric difference for various burn degrees. For this purpose, extensive measurement campaigns across the microwave frequency band from 500 MHz - 10 GHz were conducted. Based on the analysis of dielectric data, each skin region of interest (ROI) has its own dielectric properties. Additionally, we developed a proof of concept non-invasive flexible microwave sensor based on the dielectric database collected from burnt ex-vivo human tissue samples. In this way, we could distinguish between phantoms with different dielectric properties in the burned human tissue sample range.
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| 45. |
- Rangaiah, Pramod K. B., et al.
(author)
-
Clustering of Dielectric and Colour Profiles of an Ex-vivo Burnt Human Skin Sample
- 2020
-
In: 14th European Conference on Antennas and Propagation (EuCAP). - 9788831299008 - 9781728137124
-
Conference paper (peer-reviewed)abstract
- This work aims to introduce two techniques to characterize human burnt skin based on permittivity measurement and image processing. The first method is the sectorized measurement of permittivity (dielectric profiling, DEP) by using an open-end coaxial probe technique. The second method is the analysis of color variation in the burnt skin sample through image processing. Statistical analysis is done using tools such as Analysis of Variance (ANOVA), k-means, in order to classify, evaluate the data. As part of the classification, the experimental data are clustered into five groups based on the distribution of means (dielectric profiles) and centroids (color profiles). The color image is converted into a gray image and resized to a one-dimensional array. Furthermore, the analysis is done based on the intensity range, various centroid values, and silhouette analysis. The clustering results we obtained with these two methods can be used for comparing the dielectric characteristics with the color variation of the burnt human skin to assess burn degree.
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| 46. |
- Rangaiah, Pramod K. B., et al.
(author)
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Design of constant width branch line directional coupler for the microwave sensing application
- 2020
-
In: 14th European Conference on Antennas and Propagation (EuCAP). - 9788831299008 - 9781728137124
-
Conference paper (peer-reviewed)abstract
- This paper investigates the design of directional branch-line coupler using constant width multiple sections of series and open microstrip line stubs. This device is operating at the center frequency of 2.45 GHz. The designed coupler is having good performance for the frequency band 2-3 GHz. The proposed design is compared with a typical branch line coupler and shows the improved performance. The design is simulated and fabricated on the Fibreglass-resin laminate (FR4) substrate of height 1.5 mm. The results of simulated and experimented circuits are discussed and analyzed. The circuit is measured using Combination Analyzer N9918A Field Fox Handheld Microwave Analyzer. The proposed topology is easy to design and fabricate with a planar microstrip line technology. The designed coupler shows the good results at 2.45GHz i.e. S 11 = -61.26 dB, S 21 = -45 dB, S 31 = -2dB and S 41 = -4.5dB. The main target of this work is to design a coupler to differentiate between transmitted and reflected signals in the split ring resonator (SRR) sensor for Bone Density Measurement Analysis (BDAS) system.
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| 47. |
- Rangaiah, Pramod, et al.
(author)
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Preliminary Analysis of Burn Degree Using Non-invasive Microwave Spiral Resonator Sensor for Clinical Applications
- 2022
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In: Frontiers in Medical Technology. - : Frontiers Media S.A.. - 2673-3129. ; 4
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Journal article (peer-reviewed)abstract
- The European "Senseburn" project aims to develop a smart, portable, non-invasive microwave early effective diagnostic tool to assess the depth(d) and degree of burn. The objective of the work is to design and develop a convenient non-invasive microwave sensor for the analysis of the burn degree on burnt human skin. The flexible and biocompatible microwave sensor is developed using a magnetically coupled loop probe with a spiral resonator (SR). The sensor is realized with precise knowledge of the lumped element characteristics (resistor (R), an inductor (L), and a capacitor (C) RLC parameters). The estimated electrical equivalent circuit technique relies on a rigorous method enabling a comprehensive characterization of the sensor (loop probe and SR). The microwave resonator sensor with high quality factor (Q) is simulated using a CST studio suite, AWR microwave office, and fabricated on the RO 3003 substrate with a standard thickness of 0.13 mm. The sensor is prepared based on the change in dielectric property variation in the burnt skin. The sensor can detect a range of permittivity variations (ε r 3-38). The sensor is showing a good response in changing resonance frequency between 1.5 and 1.71 GHz for (ε r 3 to 38). The sensor is encapsulated with PDMS for the biocompatible property. The dimension of the sensor element is length (L) = 39 mm, width (W) = 34 mm, and thickness (T) = 1.4 mm. The software algorithm is prepared to automate the process of burn analysis. The proposed electromagnetic (EM) resonator based sensor provides a non-invasive technique to assess burn degree by monitoring the changes in resonance frequency. Most of the results are based on numerical simulation. We propose the unique circuit set up and the sensor device based on the information generated from the simulation in this article. The clinical validation of the sensor will be in our future work, where we will understand closely the practical functioning of the sensor based on burn degrees. The senseburn system is designed to support doctors to gather vital info of the injuries wirelessly and hence provide efficient treatment for burn victims, thus saving lives.
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| 48. |
- Redzwan Mohd Shah, Syaiful, et al.
(author)
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Improved Sensor for Non-invasive Assessment of Burn Injury Depth Using Microwave Reflectometry
- 2019
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In: 2019 13th European Conference on Antennas and Propagation (EuCAP). - 9788890701887
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Conference paper (peer-reviewed)abstract
- The European project “Senseburn” aims to develop a non-invasive diagnostic instrument for assessing the depth and propagation of human burns in the clinical scenario. This article introduces an improved flexible microwave split-ring resonator-based sensor, as a new development in this project. The excitation system and the fabrication process are the major improvements with respect to its precedent microwave sensor, both based in polydimethylsiloxane (PDMS) and copper. Both improvements are introduced together with the design of the sensor and of the experimental setup. Human tissue emulating phantoms are designed, fabricated, validated, and employed to emulate different burn depths and to validate the conceptual functionality of the proposed sensor. The Keysight dielectric probe 85070E is employed for the phantom validation. The analysis suggests that the sensor could estimate the burn depth. Future works will be carried out with ex vivo human tissues.
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| 49. |
- Redzwan, Syaiful, et al.
(author)
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Analysis of Thickness Variation in Biological Tissues using Microwave Sensors for Health Monitoring Applications
- 2019
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In: IEEE Access. - 2169-3536. ; 7, s. 156033-156043
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Journal article (peer-reviewed)abstract
- Microwave sensing technique is a possible and attractive alternative modality to standard Xrays,magnetic resonance imaging, and computed tomography methods for medical diagnostic applications.This technique is beneficial since it uses non-ionizing radiation and that can be potentially used for themicrowave healthcare system. The main purpose of this paper is to present a microwave sensing techniqueto analyze the variations in biological tissue thickness, considering the effect of physiological and biologicalproperties on microwave signals. With this goal, we have developed a two-port non-invasive sensor systemcomposed of two split ring resonators (SRRs) operating at an Industrial, Scientific, and Medical frequencyband of 2.45 GHz. The system is verified using the amplitude and phase of the transmitted signal in ex-vivomodels, representing different tissue thicknesses. Clinical applications such as the diagnosis of muscularatrophy can be benefitted from this study.
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| 50. |
- Redzwan, Syaiful, et al.
(author)
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Initial in-vitro trial for intra-cranial pressure monitoring using subdermal proximity-coupled split-ring resonator
- 2018
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In: IMBioc 2018 - 2018 IEEE/MTT-S International Microwave Biomedical Conference. - : Institute of Electrical and Electronics Engineers (IEEE). - 9781538659182 ; , s. 73-75
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Conference paper (peer-reviewed)abstract
- Intra cranial pressure (ICP) monitoring is used in treating severe traumatic brain injury (TBI) patients. All current clinical available measurement methods are invasive presenting considerable social costs. This paper presents a preliminary investigation of the feasibility of ICP monitoring using an innovative microwave-based non-invasive approach. A phantom mimicking the dielectric characteristics of human tissues of the upper part of the head at low microwave frequencies is employed together to a proof-of-concept prototype based on the proposed approach consisting in a readout system and a sub-dermally implanted passive device, both based in split ring resonator techniques. This study shows the potential of our approach to detect two opposite pressure variation stages inside the skull. The employed phantom model needs to be improved to support finer variations in the pressure and better phantom parts, principally for the skull mimic and the loss tangent of all mimics.
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