Search Results (3,238)

Gait phase recognition systems based on surface electromyographic signals (EMGs) are crucial for developing advanced myoelectric control schemes that enhance the interaction between humans and lower limb assistive devices. However, machine learning models used in this context, such as Linear Discriminant Analysis (LDA) and Support Vector Machine (SVM), typically experience performance degradation when modeling the gait cycle with more than just stance and swing phases. This study introduces a generalized phasor-based feature extraction approach (PHASOR) that captures spatial myoelectric features to improve the performance of LDA and SVM in gait phase recognition. A publicly available dataset of 40 subjects was used to evaluate PHASOR against state-of-the-art feature sets in a five-phase gait recognition problem. Additionally, fully data-driven deep learning architectures, such as Rocket and Mini-Rocket, were included for comparison. The separability index (SI) and mean semi-principal axis (MSA) analyses showed mean SI and MSA metrics of 7.7 and 0.5, respectively, indicating the proposed approach’s ability to effectively decode gait phases through EMG activity. The SVM classifier demonstrated the highest accuracy of 82% using a five-fold leave-one-trial-out testing approach, outperforming Rocket and Mini-Rocket. This study confirms that in gait phase recognition based on EMG signals, novel and efficient muscle synergy information feature extraction schemes, such as PHASOR, can compete with deep learning approaches that require greater processing time for feature extraction and classification. Full article

This review explores significant advancements in polymer science and fabrication processes that have enhanced the performance and broadened the application scope of microfluidic devices. Microfluidics, essential in biotechnology, medicine, and chemical engineering, relies on precise fluid manipulation in micrometer-sized channels. Recent innovations in polymer materials, such as flexible, biocompatible, and structurally robust polymers, have been pivotal in developing advanced microfluidic systems. Techniques like replica molding, microcontact printing, solvent-assisted molding, injection molding, and 3D printing are examined, highlighting their advantages and recent developments. Additionally, the review discusses the diverse applications of polymer-based microfluidic devices in biomedical diagnostics, drug delivery, organ-on-chip models, environmental monitoring, and industrial processes. This paper also addresses future challenges, including enhancing chemical resistance, achieving multifunctionality, ensuring biocompatibility, and scaling up production. By overcoming these challenges, the potential for widespread adoption and impactful use of polymer-based microfluidic technologies can be realized. Full article

This study was designed to examine the association between myocardial concentrations of the trace elements Cu, Fe, Mn, Mo, and Zn and the expression of mitochondrial unfolded protein response (UPRmt) elements and the age of patients who received heart transplantation or a left-ventricular assist device (ageHTx/LVAD). Inductively coupled plasma mass spectrometry was used to determine the concentration of Cu, Fe, Mn, Mo, and Zn in the myocardium of control subjects and patients undergoing heart transplantation or left-ventricular assist device (LVAD) implantation. We used ELISA to quantify the expression of UPRmt proteins and 4-Hydroxynonenal (4-HNE), which served as a marker of oxidative-stress-induced lipid peroxidation. Concentrations of Cu, Mn, Mo, and Zn were similar in the control and heart failure (HF) myocardium, while Fe showed a significant decrease in the HF group compared to the control. A higher cumulative concentration of Fe and Zn in the myocardium was associated with reduced age_HTx/LVAD, which was not observed for other combinations of trace elements or their individual effects. The trace elements Cu, Mn, and Zn showed positive correlations with several UPRmt proteins, while Fe had a negative correlation with UPRmt effector protease YME1L. None of the trace elements correlated with 4-HNE in the myocardium. The concentrations of the trace elements Mn and Zn were significantly higher in the myocardium of patients with dilated cardiomyopathy than in patients with ischemic cardiomyopathy. A higher cumulative concentration of Fe and Zn in the myocardium was associated with a younger age at which patients received heart transplantation or LVAD, potentially suggesting an acceleration of HF. A positive correlation between myocardial Cu, Mn, and Zn and the expression of UPRmt proteins and a negative correlation between myocardial Fe and YME1L expression suggest that these trace elements exerted their actions on the human heart by interacting with the UPRmt. An altered generation of oxidative stress was not an underlying mechanism of the observed changes. Full article

In end-stage heart failure, which is characterized by persistent or progressive ventricular dysfunction despite optimal medical therapy, a left ventricular assist device (LVAD) can be beneficial. Congestive heart failure provokes inflammatory and prothrombotic activation. The aim of this study was to evaluate the serum concentration of citrullinated histone 3 (CH3) representing neutrophil extracellular trap (NET) formation in patients referred for LVAD implantation. There were 10 patients with a median age of 61 (57–65) years enrolled in a prospective single-center analysis who underwent LVAD implantation. The CH3 plasma concentration was measured preoperatively and on the 1st and 7th postoperative days, followed by control measurements on the median (Q1–3) 88th (49–143) day. The preoperative CH3 concentration strongly correlated with brain natriuretic peptide (r = 0.879, p < 0.001). Significant differences in CH3 serum concentration were observed between pre- and postoperative measurements, including an increase on the first postoperative day (p < 0.001), as well as a decrease on the seventh day (p = 0.016) and in follow-up (p < 0.001). CH3 concentration, as a marker of NET formation, decreases after LVAD implantation. Full article

The H9 subtype of avian influenza virus (AIV) has been characterized by its rapid spread, wide range of prevalence, and continuous evolution in recent years, leading to an increasing ability for cross-species transmission. This not only severely impacts the economic benefits of the aquaculture industry, but also poses a significant threat to human health. Therefore, developing a rapid and sensitive detection method is crucial for the timely diagnosis and prevention of H9 AIVs. In this study, a real-time fluorescent reverse transcription recombinase-aided isothermal amplification (RT–RAA) technique targeting the hemagglutinin (HA) of H9 AIVs was established. This technique can be used for detection in just 30 min at a constant temperature of 42 °C, and it exhibits good specificity without cross-reactivity with other viruses. Sensitivity tests revealed that the detection limit of RT–RAA was 163 copies per reaction, and the visual detection limit was 1759 copies per reaction at a 95% confidence interval, both of which are capable of detecting low concentrations of standards. Furthermore, RT–RAA was applied to detect 155 clinical samples, and compared to real-time fluorescent quantitative PCR (RT–qPCR), RT–RAA demonstrated high accuracy, with a specificity of 100% and a kappa value of 0.96, indicating good correlation. Additionally, with the assistance of a portable blue imaging device, we can visually observe the amplification products, greatly facilitating rapid detection in resource-limited environments. The RT–RAA detection method developed in this study does not require expensive equipment or highly skilled staff, making it beneficial for the accurate and low-cost detection of H9 AIVs. Full article

This paper presents the development of the hardware and software architecture of a sixdegrees of freedom (DOF) parallel robot (PARA-SILSROB) by illustrating all the stages undertaken to achieve the experimental model of the robot. Based on the experimental model, the control architecture is also presented, which is primarily based on a master–slave control system through which the surgeon controls the robot using the master console composed of commercial peripheral components (two 3D Space Mouse devices, computer, and keyboard) integrated with the solution developed in this study and presented in this paper. The robot was developed also according to the surgical protocol and surgeon’s requirements, and for the functionality testing of the mechanical structure, two experimental stands were used. The first stand presented several surgical steps, such as manipulation, resection, and suture of experimental tissues (simulating real-life robot-assisted surgical maneuvers) using commercial instruments. The second stand presented a simulation of an esophagectomy for esophageal cancer and digestive reconstruction through a right intercostal approach. For this testing phase, the organs were created using 3D reconstruction, and their simplified models were 3D printed using PolyJet technology. Furthermore, the input trajectory generated using the master console was compared with the robot actuator’s movements and the obtained results were used for validation of the proposed robot control system. Full article

The operation of control devices in a water distribution network establishes a transient flow that leads to pressure oscillation during a certain time. Depending on the pressure wave’s amplitude, infrastructure can be exposed to dangerous pressure levels, collapsing or breaking the pipes. Predicting the maximum and minimum head pressure values caused by an operation can assist in the design of safety devices and increase the lifespan of the distribution network. Nevertheless, the calculation of the pressure wave magnitude based on hydraulic equations can be time consuming, reducing the possibility of an optimal approach for designing a protection system. In this sense, this study presents a data-driven model for predicting pressure values caused by transient flows in a water distribution network. The methodology is implemented using an ensemble tree linked to the XGBoost algorithm and it is applied in two case studies. Full article

As devices become more miniaturized and integrated, the heat flux density has increased, highlighting the issue of heat concentration, especially for low thermal conductivity gallium oxide (Ga₂O₃). This study utilizes diamond composite substrates with an AlN transition layer to assist Ga₂O₃ in rapid thermal dissipation. All samples were prepared using pulsed laser deposition (PLD) and annealed at 600–1000 °C. The microstructure, surface morphology, vacancy defects, and thermal characteristics of post-annealed Ga₂O₃ were then thoroughly investigated to determine the mechanism by which annealing temperature influences the heat transfer of heterostructures. The results demonstrate that increasing the annealing temperature can improve the crystallinity of Ga₂O₃ while also reducing oxygen vacancy defects from 20.6% to 9.9%. As the temperature rises to 1000 °C, the thermal conductivity of Ga₂O₃ reaches a maximum of 12.25 W/(m·K). However, the interface microstructure has no direct correlation with annealing temperature. At 700 °C, Ga₂O₃/diamond exhibits a maximum thermal boundary conductance of 127.06 MW/(m²·K). Higher temperatures (>800 °C) cause irregular mixtures to form near the heterointerface, intensifying phonon interface scattering and sharply deteriorating interfacial heat transfer. These findings contribute to a better understanding of the heterointerface thermal transfer influence mechanism and provide theoretical guidance for the thermal management design and physical analysis of Ga₂O₃-based power devices. Full article

Colonoscopy has a limited field of view because it relies solely on a small camera attached to the end of the scope and a screen displayed on a monitor. Consequently, the quality and safety of diagnosis and treatment depend on the experience and skills of the gastroenterologist. When a novice attempts to insert the colonoscope during the procedure, excessive pressure can sometimes be applied to the colon wall. This pressure can cause a medical accident known as colonic perforation, which the physician should prevent. We propose an assisting device that senses the pressure applied to the colon wall, analyzes the risk of perforation, and warns the physician in real time. Flexible pressure sensors are attached to the surface of the colonoscope shaft. These sensors measure pressure signals during a colonoscopy procedure. A simple signal processor is used to collect and process the pressure signals. In the experiment, a colonoscope equipped with the proposed device was inserted into a simulated colon made from a colon extracted from a pig. The processed data were visually communicated to the gastroenterologist via displays and light-emitting diodes (LEDs). The device helps the physician continuously monitor and prevent excessive pressure on the colon wall. In this experiment, the device appropriately generated and delivered warnings to help the physicians prevent colonic perforation. In the future, the device is to be improved, and more experiments will be performed in live swine models or humans to confirm its efficacy and safety. Full article

The C-MAC video stylet (Karl Storz KG, Tuttlingen, Germany) is proposed as a successor to the familiar retromolar intubation endoscope. With its flexible tip, it may be especially useful for patients with a limited mouth opening. An awake or sedated airway management technique is often preferred when a difficult airway is anticipated. Due to the challenges in preparation, sedation, topical airway anesthesia and the execution of such an airway management technique itself, these techniques are often clinically underused. The C-MAC video stylet seems to be well suited for an awake or sedated airway approach, as its handling is easier and faster than a flexible fiberscope. It does not exert pressure on the tongue as direct laryngoscopy or video laryngoscopy do. We report two cases of a difficult airway in which intubation was performed by using the C-MAC video stylet in sedated, spontaneously breathing patients. After a low dose of 3 mg midazolam IV, remimazolam was administered continuously (0.46–0.92 mg/kg/h). This was supplemented with a low dose of remifentanil (0.04–0.05 µg/kg/min). The Trachospray device (MedSpray Anesthesia BV, Enschede, The Netherlands) was used for topicalization of the upper airway by means of 4 mL of lidocaine 5%. In addition, a further 5 mL of lidocaine 5% was sprayed via an epidural catheter advanced through the oxygenation port of the C-MAC video stylet for further topicalization of the vocal cords and proximal part of the trachea. The well-coordinated steps described in these two cases may represent a blueprint and a good starting point for future studies with a larger number of patients. Full article

The biological system is not a perfect system, but it is a relatively complete system. It is difficult to realize the lower power consumption and high parallelism that characterize biological systems if lower-level information pathways are ignored. In this paper, we focus on the K, M and P pathways of visual signal processing from the retina to the lateral geniculate nucleus (LGN). We model the visual system at a fine-grained level to ensure efficient information transmission while minimizing energy use. We also implement a circuit-level distributed parallel computing model on FPGAs. The results show that we are able to transfer information with low energy consumption and high parallelism. The Artix-7 family of xc7a200tsbv484-1 FPGAs can reach a maximum frequency of 200 MHz and a maximum parallelism of 600, and a single receptive field model consumes only 0.142 W of power. This can be useful for building assistive vision systems for small and light devices. Full article

Background: Mandibular advancement devices (MADs) are considered a primary alternative treatment for adults with moderate to severe obstructive sleep apnea (OSA) who are unable to tolerate or do not respond to continuous positive airway pressure (CPAP) therapy, supported by substantial scientific evidence. While a range of designs and materials for MADs are commercially available, there is a lack of clear diagnostic guidelines to assist clinicians in selecting the most appropriate device based on a multidisciplinary evaluation of OSA patients. This narrative review seeks to outline the key characteristics of MADs that clinicians should evaluate during both the diagnostic and treatment phases for patients with OSA. Methods: An extensive search of academic databases was conducted to gather relevant studies that address therapeutic and diagnostic recommendations for the design and titration of MADs. The search was carried out across EMBASE, Scopus, PubMed, and Web of Science up to May 2024. From a total of 1445 identified citations, 1103 remained after duplicate removal. Based on the inclusion criteria, the full text of 202 articles was retrieved, and 70 studies were ultimately included in this review. The extracted data were organized to generate clinical insights, aimed at guiding orthodontists in optimizing diagnostic and decision-making processes for treating OSA patients with MADs. Results: The analysis led to the identification of key clinical questions that can assist orthodontists in enhancing their approach and choosing the appropriate appliance basing on the diagnosis and clinical dento-orofacial characteristics. Conclusions: Bibloc appliances could be preferred over mono-bloc devices due to the possibility of arranging the mandibular advancement according to the patient’s clinical condition and orofacial symptoms. Provisional devices could be used as screening tools to verify the patient’s adherence to the therapy. Regardless of the MAD design, type and programmed advancement, it must be under-lined that the rule of the orthodontist/dental specialist is secondary to the other sleep-medicine specialists (ORL, pulmonologist) and must be related to (1) a preliminary assessment of MAD usage (dental anatomical conditions), (2) testing a diagnostic MAD usable during a sleep examination (PSG or DISE), (3) final treatment with a definitive MAD. Full article

Effective training programs are essential for safely integrating exoskeletons (EXOs) in industrial workplaces. Since the effects of wearable systems depend highly upon their proper use, lack of training of end-users may cause adverse effects on users. We reviewed articles that incorporated training and familiarization protocols to train novices on proper operation/use of EXOs. Findings showed variation in training methods that were implemented to train study participants in EXO evaluation studies. Studies also indicate that multiple (up to four) sessions may be needed for novice EXO wearers to match movement patterns of experts, and training can offer benefits in enhancing motor learning in novices. Biomechanical assessments and ergonomic evaluations can be helpful in developing EXO-specific training protocols by determining training parameters (duration/number of sessions and task difficulty). Future directions include development of personalized training approaches by assessing user behavior/performance through integration of emerging sensing technologies. Application of simulators and use of data-driven approaches for customizing training protocols to individuals, tasks, and EXO design are provided along with a comprehensive training framework. Discussed elements in this article can be helpful to exoskeleton researchers in familiarizing novice users to EXOs prior to evaluation, and to practitioners in developing protocols for training workforce. Full article

Background: The HHUS market is very complex due to a multitude of equipment variants and several different device manufacturers. Only a few studies have compared different HHUS devices under clinical conditions. We conducted a comprehensive prospective observer study with a direct comparison of nine different HHUS devices in terms of B-scan quality, device handling, and software features under abdominal imaging conditions. Methods: Nine different HHUS devices (Butterfly iQ+, Clarius C3HD3, D5CL Microvue, Philips Lumify, SonoEye Chison, SonoSite iViz, Mindray TE Air, GE Vscan Air, and Youkey Q7) were used in a prospective setting by a total of 12 experienced examiners on the same subjects in each case and then assessed using a detailed questionnaire regarding B-scan quality, handling, and usability of the software. The evaluation was carried out using a point scale (5 points: very good; 1 point: insufficient). Results: In the overall evaluation, Vscan Air and SonoEye Chison achieved the best ratings. They achieved nominal ratings between “good” (4 points) and “very good” (5 points). Both devices differed significantly (p < 0.01) from the other seven devices tested. Among the HHUS devices, Clarius C3HD3 and Vscan Air achieved the best results for B-mode quality, D5CL Microvue achieved the best results for device handling, and SonoEye Chison and Vscan Air achieved the best results for software. Conclusions: This is the first comprehensive study to directly compare different HHUS devices in a head-to-head manner. While the majority of the tested devices demonstrated satisfactory performance, notable discrepancies were observed between them. In particular, the B-scan quality exhibited considerable variation, which may have implications for the clinical application of HHUS. The findings of this study can assist in the selection of an appropriate HHUS device for specific applications, considering the clinical objectives and acknowledging the inherent limitations. Full article

Gold-assisted exfoliation can fabricate centimeter- or larger-sized monolayers of van der Waals (vdW) semiconductors, which is desirable for their applications in electronic and optoelectronic devices. However, there is still a lack of control over the exfoliation processes and a limited understanding of the atomic-scale mechanisms. Here, we tune the MoS₂-Au interface using controlled external pressure and reveal two atomic-scale prerequisites for successfully producing large-area monolayers of MoS₂. The first is the formation of strong MoS₂-Au interactions to anchor the top MoS₂ monolayer to the Au surface. The second is the integrity of the covalent network of the monolayer, as the majority of the monolayer is non-anchored and relies on the covalent network to be exfoliated from the bulk MoS₂. Applying pressure or using smoother Au films increases the MoS₂-Au interaction, but may cause the covalent network of the MoS₂ monolayer to break due to excessive lateral strain, resulting in nearly zero exfoliation yield. Scanning tunneling microscopy measurements of the MoS₂ monolayer-covered Au show that even the smallest atomic-scale imperfections can disrupt the MoS₂-Au interaction. These findings can be used to develop new strategies for fabricating vdW monolayers through metal-assisted exfoliation, such as in cases involving patterned or non-uniform surfaces. Full article