Search results for "Biomedical engineering"
showing 10 items of 2020 documents
A new Frequency Domain Measure of Causality based on Partial Spectral Decomposition of Autoregressive Processes and its Application to Cardiovascular…
2019
We present a new method to quantify in the frequency domain the strength of directed interactions between linear stochastic processes. This issue is traditionally addressed by the directed coherence (DC), a popular causality measure derived from the spectral representation of vector autoregressive (AR) processes. Here, to overcome intrinsic limitations of the DC when it needs to be objectively quantified within specific frequency bands, we propose an approach based on spectral decomposition, which allows to isolate oscillatory components related to the pole representation of the vector AR process in the Z-domain. Relating the causal and non-causal power content of these components we obtain…
Polarization-sensitive hyperspectral imaging of human skin: From system design to clinical validation (Conference Presentation)
2020
We present the development and validation of a new approach for quantitative functional imaging of human skin based on the machine learning technique for the analysis of the hyperspectral skin images. The considered skin parameters include blood volume fraction, blood oxygenation, melanin content, and the epidermal layer thickness. Additionally, the degree of residual polarization of the reflected light has been analyzed. The validity of the approach has been confirmed by the initial preclinical tests with the tissue-mimicking phantoms, functional in-vivo skin tests, and pilot clinical study of type II diabetic patients. The proposed technique has great potential to be implemented in clinic…
Researches Regarding the Usage of Titanium Alloys in Cranial Implants
2014
In the last few decades, the concept of flexible manufacturing has started to gain more and more attention, as an adaptation of production methods to the increasingly varied demands by customers. Therefore, new procedures have been introduced as alternatives to the classical ones, a very promising one being incremental forming [. A possible application for this new procedure, targeted by the authors of this paper, is the manufacturing of custom-shaped prosthetic parts for use in various areas of human medicine. Such prostheses can have a functional role, when they target the replacing of a functional component of the human body, or an esthetic role, when they target the solving of problems …
Textureless macula swelling detection with multiple retinal fundus images
2011
Retinal fundus images acquired with nonmydriatic digital fundus cameras are versatile tools for the diagnosis of various retinal diseases. Because of the ease of use of newer camera models and their relatively low cost, these cameras can be employed by operators with limited training for telemedicine or point-of-care (PoC) applications. We propose a novel technique that uses uncalibrated multiple-view fundus images to analyze the swelling of the macula. This innovation enables the detection and quantitative measurement of swollen areas by remote ophthalmologists. This capability is not available with a single image and prone to error with stereo fundus cameras. We also present automatic alg…
A study on the effect of contact pressure during physical activity on photoplethysmographic heart rate measurements
2020
Heart rate (HR) as an important physiological indicator could properly describe global subject&rsquo
Semi-automated and interactive segmentation of contrast-enhancing masses on breast DCE-MRI using spatial fuzzy clustering
2022
Abstract Multiparametric Magnetic Resonance Imaging (MRI) is the most sensitive imaging modality for breast cancer detection and is increasingly playing a key role in lesion characterization. In this context, accurate and reliable quantification of the shape and extent of breast cancer is crucial in clinical research environments. Since conventional lesion delineation procedures are still mostly manual, automated segmentation approaches can improve this time-consuming and operator-dependent task by annotating the regions of interest in a reproducible manner. In this work, a semi-automated and interactive approach based on the spatial Fuzzy C-Means (sFCM) algorithm is proposed, used to segme…
Synthesis of Silver Gallium Selenide (AgGaSe2) Nanotubes and Nanowires by Template-Based Electrodeposition
2020
In this work, a systematic investigation of the different parameters that control the electrodeposition processes was carried out at the aim to synthetizing AgGaSe₂ nanostructures. We found that pH is a key parameter to control both the morphology and composition of the nanostructures. Low pH favours mainly the formation of Ag2Se nanotubes with a scarce mechanical stability, while multi-phase nanowires well anchored to the substrate were obtained at higher pH. We also found that it was necessary to increase dramatically the concentration of the gallium precursor into the deposition bath in order to obtain AgGaSe₂ owing to lower redox potential of the Ga3+/Ga couple than Ag2+/Ag and Se4+/Se.…
In vivo measurement of gastric fluid volume in anesthetized dogs
2020
Abstract The drug solubility is critical for the Biopharmaceutics Classification System (BCS), yet the criteria for solubility have not been precisely defined for dogs. In particular, the gastric fluid volume (GFV) of dogs which is used to measure the solubility has not been quantified in vivo. The aim of the work is to measure the GFV using magnetic resonance imaging (MRI) from 12 Beagle dogs weighing 9–12 kg (6 male and 6 female). We found that the average GFV within this weight range was 24.0 ± 4.2 mL. The result can be used for the BCS studies of canine drugs and also serves as a reference for other species.
Electrical stimulation with motility analysis of five parts of the gastrointestinal tract ; First evaluation of an experimental protocol in a porcine…
2018
Abstract Gastrointestinal (GI) motility disorders are frequent and clinically significant conditions with impairment of patient’s quality of life. Examples range from upper GI symptoms such as dysphagia and gastroparesis to lower GI manifestations, namely chronic-intestinal pseudo obstruction, diarrhea and constipation. Furthermore, postoperative motility disorders are common. Currently, available pharmacological or dietetic treatment options are limited. Since GI motility is based on myoelectric activity, electrical stimulation (ES) is a promising alternative. Numerous studies have demonstrated suitable pacing strategies and parameters in different GI segments. However, results of multiloc…
Photo-thermal effects in gold nanorods/DNA complexes
2015
An ingenious combination of plasmonic nanomaterials and one of the most relevant biological systems, deoxyribonucleic acid (DNA) is achieved by bioconjugating gold nanorods (GNRs) with DNA via electrostatic interaction between positively charged GNRs and negatively charged short DNA. The obtained system is investigated as a function of DNA concentration by means of gel electrophoresis, zeta-potential, DNA melting and morphological analysis. It turns out that the obtained bioconjugated systems present both effective electric charge and aggregate size that are particularly amenable for gene therapy and nanomedicine applications. Finally, the effect of the localized (photo-thermal heating) and…