While the textile based stretchable supercapacitors have been demonstrated as efficient charge storage devices, challenges in developing self powered wearable devices still exist. The present work ...describes a screen printed flexible and stretchable supercapacitor that can act as an energy buffering element for powering wearable fitness monitoring devices. The supercapacitor possesses interdigitated shaped intrinsically stretchable electrodes with free-standing serpentine interconnects. The symmetric supercapacitor relies on carbon nanotube and poly(aniline) as active materials and polyurethane as a stretch enduring binder. Such in-plane supercapacitors are realized by initially printing on a paper substrate, pre-coated with a water soluble layer, and then transferred onto a pre-strained elastomeric substrate. The supercapacitor showed excellent mechanical resiliency even though subjected to intense mechanical deformations. The electrode possessed highest areal capacitance of 167 mF/cm2 at a current density of 0.4 mA/cm2 and showed appreciable areal energy and power density of 14.9 μWh/cm2 and 0.29 mW/cm2, respectively. The supercapacitor showed conformal integration with the stretchable sweat band and which (3 devices, in series) can independently power a red light emitting diode. In combination with a flexible solar cell and a custom-made low power booster, the supercapacitor can continuously powers the wearable pulse rate sensor even in the presence of poor sunlight intensity.
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•Wearable, screen printed supercapacitor for self powering application•Interdigitated supercapacitor possesses serpentine shaped freestanding interconnects•Areal energy and power density of 14.9 μWh/cm2 and 0.29 mW/cm2, respectively•Energy buffering ability with a solar cell for powering a pulse rate sensor
Deformable electronic devices that are impervious to mechanical influence when mounted on surfaces of dynamically changing soft matters have great potential for next‐generation implantable ...bioelectronic devices. Here, deformable field‐effect transistors (FETs) composed of single organic nanowires (NWs) as the semiconductor are presented. The NWs are composed of fused thiophene diketopyrrolopyrrole based polymer semiconductor and high‐molecular‐weight polyethylene oxide as both the molecular binder and deformability enhancer. The obtained transistors show high field‐effect mobility >8 cm2 V−1 s−1 with poly(vinylidenefluoride‐co‐trifluoroethylene) polymer dielectric and can easily be deformed by applied strains (both 100% tensile and compressive strains). The electrical reliability and mechanical durability of the NWs can be significantly enhanced by forming serpentine‐like structures of the NWs. Remarkably, the fully deformable NW FETs withstand 3D volume changes (>1700% and reverting back to original state) of a rubber balloon with constant current output, on the surface of which it is attached. The deformable transistors can robustly operate without noticeable degradation on a mechanically dynamic soft matter surface, e.g., a pulsating balloon (pulse rate: 40 min−1 (0.67 Hz) and 40% volume expansion) that mimics a beating heart, which underscores its potential for future biomedical applications.
Deformable organic nanowire (NW) field‐effect transistors (FETs) with mechanical reliability are demonstrated with highly ductile and deformable NWs as the semiconductor. The NWs maintain a continuous structure under 100% strain in both channel length and width directions of the transistors. Stretchable FETs with single NWs are operated stably on a 3D soft matter substrate with dynamic volume expansion and contraction that mimics a beating heart.
Photoplethysmography (PPG) technology has been used to develop small, wearable, pulse rate sensors. These devices, consisting of infrared light-emitting diodes (LEDs) and photodetectors, offer a ...simple, reliable, low-cost means of monitoring the pulse rate noninvasively. Recent advances in optical technology have facilitated the use of high-intensity green LEDs for PPG, increasing the adoption of this measurement technique. In this review, we briefly present the history of PPG and recent developments in wearable pulse rate sensors with green LEDs. The application of wearable pulse rate monitors is discussed.
The measurement of physiological parameters is fundamental to assess the health status of an individual. The contactless monitoring of vital signs may provide benefits in various fields of ...application, from healthcare and clinical setting to occupational and sports scenarios. Recent research has been focused on the potentiality of camera-based systems working in the visible range (380-750 nm) for estimating vital signs by capturing subtle color changes or motions caused by physiological activities but invisible to human eyes. These quantities are typically extracted from videos framing some exposed body areas (e.g., face, torso, and hands) with adequate post-processing algorithms. In this review, we provided an overview of the physiological and technical aspects behind the estimation of vital signs like respiratory rate, heart rate, blood oxygen saturation, and blood pressure from digital images as well as the potential fields of application of these technologies. Per each vital sign, we provided the rationale for the measurement, a classification of the different techniques implemented for post-processing the original videos, and the main results obtained during various applications or in validation studies. The available evidence supports the premise of digital cameras as an unobtrusive and easy-to-use technology for physiological signs monitoring. Further research is needed to promote the advancements of the technology, allowing its application in a wide range of population and everyday life, fostering a biometrical holistic of the human body (BHOHB) approach.
As statins decrease the progression of sepsis and its related mortality, this study aimed to evaluate the effect of atorvastatin on survival and symptom improvement in hospitalized patients with ...COVID‐19. This randomized controlled trial was performed on 156 hospitalized patients with COVID‐19 in Bojnourd city in 2021. Patients were randomly divided into comparison (standard therapy: hydroxychloroquine + Kaletra®) and intervention groups (atorvastatin 20 mg, SD, plus standard therapy). The main outcomes were the rate of symptom improvement, duration of hospitalization, need for intubation, and mortality rate. In this study, seven patients died, two patients (2.6%) in the comparison group and five (6.6%) in the intervention group. The mean hospitalization days (p = 0.001), the pulse rate (p = 0.004), and the frequency of hospitalization in the ICU ward (18.4% vs. 1.3%) were longer and greater in the intervention group. The remission probability in the comparison group was greater (p = 0.0001). The median hospitalization days in the intervention group was longer (p < 0.001) and remission in the comparison group occurred 1.71 times sooner (hazard ratio = 1.70, 95% confidence interval = 1.22–2.38, p = 0.002). Totally, adding atorvastatin to the standard regime in this study increased hospitalization days and imposed negative effects on symptom improvement in hospitalized patients with COVID‐19.
The long-term clinical and physiological consequences of COVID-19 infection remain unclear. While fatigue has emerged as a common symptom following infection, little is known about its links with ...autonomic dysfunction. SARS-CoV-2 is known to infect endothelial cells in acute infection, resulting in autonomic dysfunction. Here we set out to test the hypothesis that this results in persistent autonomic dysfunction and is associated with post-COVID fatigue in convalescent patients.
We recruited 20 fatigued and 20 non-fatigued post-COVID patients (median age 44.5 years, 36/40 (90%) female, median time to follow up 166.5 days). Fatigue was assessed using the Chalder Fatigue Scale. These underwent the Ewing's autonomic function test battery, including deep breathing, active standing, Valsalva manoeuvre and cold-pressor testing, with continuous electrocardiogram and blood pressure monitoring, as well as near-infrared spectroscopy-based cerebral oxygenation. 24-hour ambulatory blood pressure monitoring was also conducted, and patients completed the generalised anxiety disorder-7 questionnaire. We assessed between-group differences in autonomic function test results and used unadjusted and adjusted linear regression to investigate the relationship between fatigue, anxiety, and autonomic test results.
We found no pathological differences between fatigued and non-fatigued patients on autonomic testing or on 24-hour blood pressure monitoring. Symptoms of orthostatic intolerance were reported by 70% of the fatigued cohort at the time of active standing, with no associated physiological abnormality detected. Fatigue was strongly associated with increased anxiety (p <0.001), with no patients having a pre-existing diagnosis of anxiety.
These results demonstrate the significant burden of fatigue, symptoms of autonomic dysfunction and anxiety in the aftermath of COVID-19 infection, but reassuringly do not demonstrate pathological findings on autonomic testing.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Abstract
Rotating Radio Transients are a relatively new subclass of pulsar characterized by sporadic bursting emission of single pulses. Here, we present a single-pulse analysis of a rotating radio ...transient, RRAT J0139+3336, using Five-hundred-meter Aperture Spherical radio Telescope at 1250 MHz. Within 3.32 hr of continuous observation, 152 single pulses were detected in RRAT J0139+3336, with the pulse rate of 45 pulses per hour. We perform a spectral analysis on the single pulses of this pulsar for the first time, finding its mean spectral indices to be −3.2 ± 0.2, which is steeper than most known pulsars. On a single-pulse basis, we produce the first polarimetric profile of this pulsar, which fits well with the rotating vector model. The single pulses are clearly affected by diffractive scintillation with a characteristic scintillation bandwidth of
v
sc
= 28 ± 9 MHz. The pulse energy distribution for RRAT J0139+3336 can be described by a log-normal model.
•A new bat algorithm based on iterative local search and stochastic inertial weight (ILSSIWBA) is proposed.•The global convergence of ILSSIWBA is proved by the convergence criteria of stochastic ...algorithm.•ILSSIWBA has remarkable advantages in optimization accuracy, solving speed and convergence stability.
Bat algorithm (BA) is a heuristic optimization algorithm based on swarm intelligence and the inspiration from the nature behavior of bats. It has some advantages including fast solving speed, high precision and only few parameters need to be adjusted. However, BA is easy to fall into local optima and has unstable optimization results due to low global exploration ability. In order to overcome these weakness, a new bat algorithm based on iterative local search and stochastic inertia weight (ILSSIWBA) is proposed in this paper. A kind of local search algorithm, called iterative local search (ILS) is introduced into the proposed algorithm. The ILS algorithm disturbs the local optimum and do some local re-search, so that the ILSSIWBA has strong ability to jump out of the local optima. In addition, a weight updating method, called stochastic inertia weight (SIW) is also introduced into the proposed algorithm. Considering the SIW in the velocity updating equation can enhance the diversity and flexibility of bat population, so that the ILSSIWBA has stable optimization results. Meanwhile, the pulse rate and loudness are modified to enhance the balance performance between global and local search. Moreover, the global convergence of ILSSIWBA is proved by the convergence criteria of stochastic algorithm. In the end, the ILSSIWBA is compared with directional bat algorithm (DBA) and other algorithms on 10 classic benchmark functions, CEC 2005 benchmark suite, and two real-world problems. The results show that ILSSIWBA has remarkable advantages in optimization accuracy, solving speed and convergence stability. This algorithm lays a solid foundation for solving modeling, optimization and control problems of complex systems.
In this paper, the novel concept of using heat flux sensors (HFS) to measure arterial pulse on the skin surface is validated. The heat flux (HF) signal is compared with simultaneously measured ...electrocardiogram (ECG) and photoplethysmography (PPG) signals during both rest and initial recovery from exercise. It is found that the waveform measured with the HF sensor above the radial artery has similar shape to PPG and demonstrates a clear temporal alignment between the HF pulse waves and both the PPG and ECG signals. Further, it is shown that HF measurement can be used to consistently track the arterial pulse at varying skin-to-ambient temperature gradients.
Objective: Atrial fibrillation (AF) causes marked risk for patients, while silent fibrillation may remain unnoticed if not suspected and screened. Development of comfortable yet accurate beat-to-beat ...heart rate (HR) monitoring with good AF detection sensitivity would facilitate screening and improve treatment. The purpose of this study was to evaluate whether a wrist-worn photoplethysmography (PPG) device can be used to monitor beat-to-beat HR accurately during post-operative treatment in patients suffering from AF and whether wrist-PPG can be used to distinguish AF from sinus rhythm (SR). Approach: Twenty-nine patients (14 with AF, 15 with SR, mean age 71.5 years) with multiple comorbidities were monitored during routine post-operative treatment. The monitoring included standard ECG, finger PPG monitoring and a wrist-worn PPG monitor with green and infrared light sources. The HR from PPG sensors was compared against ECG-derived HR. Main results: The wrist PPG technology had very good HR and beat detection accuracy when using green light. For the SR group, the mean absolute error (MAE) for HR was 1.50 bpm, and for the inter-beat intervals (IBI), the MAE was 7.64 ms. For the AF group, the MAE for HR was 4.28 bpm and for IBI, the MAE was 14.67 ms. Accuracy for the infrared (IR) channel was worse. Finger PPG provided similar accuracy for HR and better accuracy for the IBI. AF detection sensitivity using green light was 99.0% and the specificity was 93.0%. Performance can be improved by discarding unreliable IBI periods. Significance: Results suggest that wrist PPG measurement allows accurate HR and beat-to-beat HR monitoring also in AF patients, and could be used for differentiating between SR and AF with very good sensitivity.
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