Neurovascular coupling (NVC) in the brain is well studied and is one of the physical stimulation responses triggered by the central nervous system. NVC, or functional hyperemia, is described as the local blood flow increase due to the release of vasodilator chemicals from neuronal cells into vessels. This behavior also exists in the retinal vasculature. However, it was only measured in the ipsilateral retina. Assessing photic stimulation in the contralateral retina can shed light on retina-retina or brain-retina neural pathways. Emerging technologies provide new ways of measuring this effect with high spatial and temporal resolution. Adaptive optics has been used in astronomy with great results. Yet, implementing this technology in retinal fundus imaging was revolutionary in providing extremely high spatial resolution images. The RTX1 ™ is an adaptive optics retinal camera capable of ipsilateral light flicker to stimulate photoreceptors and document the induced response. The NVC in the ipsilateral retina has been successfully assessed using this equipment. Using the RTX1™ with an external flickering device, it is possible to explore contralateral stimulation's effects. The first preliminary tests show a full working prototype (contralateral stimulation) with successful software integration into the RTX1TM. A set of images was acquired to fully document the entire procedure and evaluate all components. Further evaluation will be necessary to optimize flicker-related parameters in the quest for the ipsilateral NV C response.
This study aims to investigate the impact of compressive loading on endothelial cell migration pattern in angiogenesis using a meshless discretization technique, combined with a reaction-diffusion formulation. In silico models are highly valuable for understanding the dynamics of biological systems, and numerical models allow for testing different laboratory protocols and deducing which ones produce the best outcomes. In the proposed model, angiogenesis was simulated in response to a reaction-diffusion equation for vascular endothelial growth factor (VEGF) in a 5×5 mm 2 square domain and using the Radial Point Interpolation Method (RPIM). The compressive loading was applied as a hydrostatic pressure of around 0.0067 MPa, in a specific zone in the domain to simulate the domain stress-strain interactions. The effect of compressive loading on angiogenesis sprouting patterns is analysed, and the results show that compression load affects the VEGF diffusion gradient and increases the VEGF concentration in the region where the compression was applied, causing the capillary to move away from the VEGF release region. Overall, this study sheds light on the role of mechanical stimuli in angiogenesis and provides a basis for further research in this area.
The continuous monitoring of vital signals is crucial in the diagnosis of cardiovascular diseases. With the focus on a continuous and non-intrusive acquisition of ballistocardiographic signal, a mobile seat instrumentalized with optical fiber sensors based on fiber Bragg gratings (FBGs) is proposed. The development of a six-sensor network will allow the study of the feasibility of their positioning to aim a greater efficiency. To calculate the heart rate, a time domain algorithm was developed based on the determination of the period between J-peaks of the ballistocardiograph. This model was tested on ten volunteers, in a sitting position, with data acquisitions carried out in periods of three minutes. To evaluate its performance, the results were compared with a wearable reference system, obtaining an accuracy greater than 95% for the majority of the participants, thus verifying that the developed system overcame the proposed objective.
Mesh-based numerical methods have several limitations to simulate biofluids at a micro scale level, as they do not represent the multiphase component of them. In contrast, atomistic methods have the ability to simulate fluids with more than one phase, where the mesh is replaced by interacting particles. The LAMMPS code is a classical method of the molecular dynamics simulation, frequently used to assess the flow dynamics of particles. The main goal of this work is to compare the classical Molecular Dynamics (MD) with the finite volume method. Thus, for both type of simulations the same Newtonian fluid was used to assess the flow behavior along a hyperbolic contraction microchannel. The strain rate obtained for the flow rate of 0.22 and 1.00 ml/h have shown a good agreement between both methods.
Cardiac surgery equipment assists healthcare professionals in the surgical treatment of pathologies of the heart and blood vessels. This equipment is considered critical as the patient's life depends on it. Therefore, it is crucial that the equipment manager ensures it is always in the best operating conditions and in compliance with the applicable regulatory requirements (e.g., electrical safety requirements). Three of the most used cardiac surgery devices are the intra-aortic balloon pump, the extracorporeal circulation machine and the heat exchanger. This paper presents a compilation of relevant information about this equipment, including maintenance procedures and enumeration of the most common malfunctions, based on the analysis of maintenance reports covering the lifecycle of these devices.
This study presents non-invasive subject specific analysis using innovative tools from dynamic systems theory and image processing for sagittal plane anatomical marker tracking and digital filtering for detection of normalized phase differences of lower limb joint angular displacement and angular velocity coordination during long and short countermovement (CM) and muscle stretch-shortening cycle. Applied metrics captured at low-dimensional level (one variable - the phase) differences of CM neuromuscular control of lower limb joint coordination with greater dissimilarity between long and short CM, whereas no CM condition shares higher phase coordination at the hip, knee, ankle.
Sickle Cell anemia (SCA) is a hereditary hemoglobinopathy with formation of hemoglobin S, associated with severe health outcomes. Currently, induction of fetal hemoglobin (HbF) is one of the most promising therapeutic strategies. Here we aimed to assess the potential of the natural compound Quercetin, in transcriptional expression of globin and HbF regulatory/silencing genes. In this study, the K562 cell line was used as an SCA model. Cells were exposed to Quercetin at final concentrations of 0.2 and 20 µM, and Hydroxyurea (25 µg/mL) was used as a positive control. Cell viability and proliferation were assessed through trypan blue exclusion assay. Transcriptional expression was performed by RT-qPCR using specific primers. Significant differences were analyzed using a t-test. No cytotoxic effects were observed following exposure to Quercetin. Transcriptional analysis demonstrated that Quercetin affects mRNA levels of HbF regulatory/silencing genes with associated downregulation of BCL11A, MYB, KLF1 and HBB and upregulation of HBG and BGLT3, as well as alterations in the expression of miRNAs involved in HbF post-transcriptional regulation. Our results sustain Quercetin potential as an HbF inducer with associated upregulation of HbF-activators and decreased expression of HbF-inhibitors. These data support the need for further studies in order to confirm the potential of this compound as a new therapeutic option for $\beta$ -hemoglobinopathies in the future.
Wearable Health Devices (WHDs) are increasingly becoming an integral part of daily life and significantly contributing to self-monitoring in healthcare. WHDs have a wide range of applications, ranging from sports to clinical settings, where the monitoring of cardiovascular health, particularly through ECG, plays a crucial role. This study introduces a unique WHD called VitalSticker, which exhibits distinctive features such as having a comfortable tiny patch form-factor to be attached to the chest, collecting multiple vital signs with medical-grade quality (ECG, respiration, temperature and actigraphy) and seamlessly sending data to a companion app. This paper encompasses a detailed description of the hardware, firmware, and case design of the WHD. A study was conducted to assess the quality of the ECG signal acquired by VitalSticker, comparing it with the signal obtained from a CE medical-grade certified ambulatory device. The results demonstrate that our VitalSticker achieves similar medical-grade quality when compared to the reference device, surpassing its counterpart in several specifications. Furthermore, this study presents the successful implementation of an ECG baseline wander correction filter that runs on the tiny on-board wearable microcontroller without introducing any artifacts into the ECG signal, reducing the need for further processing for this outside the wearable patch.
Agriculture work is physically demanding and the sector workers have a high incidence of musculoskeletal disorders. The shift to Agriculture 5.0 and the advancement of precision agriculture have involved the digitalization of this industry, but tend to marginalise the workers, though they are still essential to more thorough tasks that cannot be automated. In order to tackle the necessity to support the monitoring of agriculture workers, we developed quantification algorithms, incorporated in a mobile application, which calculate metrics based on the signals gathered by wearable sensors. Our proximity to the Douro region lead us to focus on metrics that could be more meaningful for viniculture, namely the quantification of trunk inclinations and shear cuts, very common in this production. The developed algorithms showed an error of 1.36 ° for the calculus of inclination and 2.43 cuts for the prediction of cuts when tested with on-field data. These results suggest that the created system has the viability to be used by agricultures and give reliable feedback on their workers.
Pelvic organ prolapse (POP) is a disease that progressively affects women, creating a growing demand for the development of new devices and materials capable of diagnosing and treating the problem more quickly and effectively. The device currently undergoing validation is composed of a speculum equipped with multiple sensors, accoupled into the outer faces of the speculum blades, with the purpose to gauge the strength or muscular tension of the vaginal walls. The values measured by the device were of the same order of magnitude between ex vivo and in vivo study, values that vary between 0,15 and 1,33 N and tend to increase with the increment of the speculum opening. The device that has been developed has the capability to assess variations in the distribution of force in different spatial locations. The device has consistently provided reliable measurements, motivating us to continue improving and validating it.
Detecting and monitoring protein aggregates is important to evaluate disease progression, particularly in neurodegenerative disorders such as Parkinson's and Alzheimer's. Apart from the evaluation of disease progression, the detection of protein aggregates is used during the manufacturing process of some pharmaceutical formulations because it is extremely important to monitor the levels of protein aggregates given the potential immunogenic responses they can induce in the human body. The systems yet developed to detect these biological entities are often complex, expensive, and, in some cases, require specialized personnel to handle them. Thus, the application of such devices becomes difficult in resource-limited settings. Here we propose a simpler low-cost alternative - a smartphone-based fluorescence detection device - for the detection of protein aggregates. The results obtained with the developed system were consistent with measurements made with a commercial spectrometer, therefore proving the suitability of the proposed device for this application.
UV protection is crucial for sunglasses, and the World Health Organization and the International Commission on Non-Ionizing Radiation Protection have set safe limits for UV radiation exposure. We conducted a study using the SMARTS2 model to calculate solar UV irradiance on a vertical surface simulating sunglasses. The radiant exposure on the eye's surface was calculated for the 280nm-400nm range, following ICNIRP recommendations. Results showed that the tested lens failed to meet the UV-A safe limit, even after the aging process. Incorporating ICNIRP safe limits into standards is necessary for better UV protection. While the importance of UV protection when wearing sunglasses is emphasized, there is a lack of quantification regarding pupil dilation. We estimated pupil diameter and calculated UV influx through the pupil, considering surrounding luminance. Pupil diameter ranged from 2mm to 7.8mm, adjusting to brightness changes. At midday, when the sun is less direct, the pupil is larger. Wearing and not wearing sunglasses exhibited opposite behaviors, highlighting the need to understand how light attenuation affects pupil diameter through transmittance spectra analysis.
Instrumented canes have capabilities that allow them to provide functionalities beyond what a traditional cane can offer its user. This study presents a survey of existing instrumented canes, both of commercial and research nature. We identify the major types of features and functionalities offered by these canes, and also focus with particular interest on those offering capabilities aimed at improving the gait of Parkinson's patients, namely the provision of visual, auditory and tactile cues. We find that although special-purpose features dedicated to Parkinson's patients specific needs are commonly experimented with in research contexts, they are usually absent from commercially available solutions, which focus mainly on utility and emergency management features.
Using surface resonance (SPR) as a sensitivity enhancer, this work describes the development of a transmissive multimode optical fiber sensor with a gold (Au) thin film that measures glucose concentration. The fiber's cladding was initially removed, and an Au layer was then sputtered onto its surface to simultaneously excite SPR and reflect light, making the SPR sensor extremely sensitive to changes in the environment's refractive index. A range of glucose concentrations, from 0.0001 to 0.5000 g/ml, were tested on the sensor. A maximum sensitivity of 161.302 nm/(g/mL) was attained for the lowest glucose concentration, while the highest concentration yielded a sensitivity of 312.000 nm/(g/mL). The proposed sensor's compact size, high sensitivity, good stability and practicality make it a promising candidate for a range of applications, including detecting diabetes.
The diagnosis of infections in hospital or clinical settings usually involves a series of time-consuming steps, including biological sample collection, culture growth of the organism isolation and subsequent characterization. For this, there are diverse infection biomarkers based on blood analysis, however, these are of limited use in patients presenting confound processes as inflammatory process as occurring at intensive care units. In this preliminary study, the application of serum analysis by FTIR spectroscopy, to predict bacteraemia in 102 critically ill patients in an ICU was evaluated. It was analysed the effect of spectra pre-processing methods and spectral sub-regions on t-distributed stochastic neighbour embedding. By optimizing Support Vector Machine (SVM) models, based on normalised second derivative spectra of a smaller subregion, it was possible to achieve a good bacteraemia predictive model with a sensitivity and specificity of 76%. Since FTIR spectra of serum is acquired in a simple, economic and rapid mode, the technique presents the potential to be a cost-effective methodology of bacteraemia identification, with special relevance in critically ill patients, where a rapid infection diagnostic will allow to avoid the unnecessary use of antibiotics, which ultimately will ease the load on already fragile patients' metabolism.
Phytoplankton monitoring using fluorescence spectroscopy techniques has been frequently used over time. This monitoring is based on the detection of the main photosynthetic pigment, chlorophyll-a, as its concentration is widely used as a proxy of phytoplankton biomass in the water column. However, the fluorometers available for their measurement and use in the field are still quite expensive and bulky, which limit its in-situ and widespread use. This paper presents the development of a low-cost, simple and portable device for measuring phytoplankton chlorophyll-a concentration at sea. The fabricated device revealed a good performance for measuring chlorophyll-a concentrations, from 0.1 up to 75 µg/L with potential for in-situ, real-time and long-term monitoring.
Phytoplankton are microscopic marine algae that constitute the foundation of the aquatic food web. They are essential to drive life in the oceans but can also be harmful in the form of algae blooms, either by producing phytoplankton toxins or massive biomass proliferation. Microalgae cell size is a relevant morphologic trait that can help identifying species responsible for these blooms at early stages. Sorting microalgae based on cell size reduces the complexity of the sea water samples, making identification easier, and allows enrichment of the target size. This work reports the study and optimization of an inertial microfluidic device for size-based separation and concentration of microparticles/microalgae. It is demonstrated the suitability of the device for sorting and separation of microparticles/microalgae of varying sizes. Furthermore, the enrichment of microalgae was also demonstrated, achieving a 2.5-fold increase fluorescence detection with only one spiral passage. This method is well suited for integration in monitoring devices due to its easy fabrication and integration in miniaturized systems and has potential as a pre-sorting and enrichment step prior to analysis. In addition, it can be used to improve the monitoring performance of early harmful algal blooms, or detection of microplastics in the water.
The proposed new mechanism, BKS, converts the movement of rotation into linear movement, torque into compression by increasing the density of the mass on which it acts decreasing its original volume under measured conditions. The chosen material for BKS must be more resistant than the material on which it will be applied, making it possible to drill it. To do this, it makes the collected mass smaller than the original by cutting and breaking its original structure, forming granular solids, moving them like fluids into the internal volume of the BKS due to the insertion torque applied, increasing the coefficient of friction between these materials. This is an innovative simple machine that can compact particles within its internal volume, making the material collected denser under mechanical pressure. Previous experimental studies from the authors have shown that the BKS modifies its original surface, incorporating inside its volume the same material on which's applied, standardizing inner volume measurement under given precise conditions. With the introduction of this new simple machine, the possibility to create and develop new mechanical and biomechanical devices is expanded by applying the mechanical advantage determined in this work.
The assessment of differences between skeletal age and chronological age in childhood is often based on the comparison of the patient's left hand x-ray with a reference atlas, performed by a experienced professional. This procedure involves a manual image analysis, that can be subject to inter rater variability posing several problems for clinical applications. In this paper a new methodology for skeleton maturation estimation based on automatic hand X-ray assessment for pediatric applications on a low resource devices (e.g. mobile device) is proposed. The pipeline covers hand-area estimation and bone-area estimation to achieve maturation scores which are then indexed with references images, separately for male and female. The proposed approach is based on simple image processing functions always bearing in mind the application on a mobile context. The involved steps are thoroughly presented and all the used functions are explained. The performance of the system was then evaluated using the complete pipeline. The obtained results pointed to an average error rate of 15,38±3,31%, which is subject to improvements. In particular, contrast enhancement in some lower quality images still offers some challenges.
Plants gather and process information about their surroundings to make decisions that prioritize their well-being while considering the environment. These decisions are conveyed through electrical signals within and between cells, mainly in the form of action and variation potentials, in response to stimuli, including mechanical vibrations, changes in temperature, light intensity, and humidity. Although the ability of some plants, such as the Mimosa pudica, to react to sudden environmental stimuli (e.g., touch) is well known, their long-term electrical response under slow environmental changes remains not fully understood. Here, a multi-source monitoring system has been developed to collect and store electrical signals from the plant Mimosa pudica, and surrounding environmental temperature and humidity, over a period of approximately 5 days. A real-time dashboard shows the environmental temperature and variation potential (VP) from Mimosa pudica. The VP mimics the environmental temperature changes, with an associated delay. Our long-term physiological observations suggest that environmental temperature sensing in the plant Mimosa pudica can be monitored and is likely driven by bioelectricity.
