Blue Light and Eye Damage: A Review on the Impact of Digital Device Emissions

The pandemic and lockdown caused by COVID-19 accelerated digitalization. Personal digital devices, emitting high-energy light, namely in the blue wavelength, have raised concerns about possible harmful effects on users' eyes. Scientific research history has shown a relationship between exposure to blue light and changes in ocular structures. The main goal of this review is to examine frequent and prolonged exposure to blue radiation from computers, tablets and smartphones and its consequences on vision and ocular structures. Bibliographic research was carried out on changes induced by blue light in ocular structures, the cornea, the crystalline lens and the retina based on the following scientific databases: BioOne Complete™;Google Scholar™;Paperity™;PubMed™;and ScienceOpen™. The most significant studies on blue light and ocular damage were selected and reviewed. The most relevant bibliographic data were analyzed and summarized and some gaps in the theme of blue light from digital devices were identified. The experimental need to acquire additional new data is suggested. The hypothesis that continued use of digital devices enriched with blue light may interfere with the biological tissues of the cornea, crystalline lens, or retina is not clarified in the available scientific evidence. Therefore, additional studies are needed to answer this problem. © 2023 by the authors.

Diode laser in management of loss of taste sensation in patients with post-COVID syndrome: a randomized clinical trial.

OBJECTIVE: Loss of taste (ageusia) is a symptom observed following recovery from COVID-19 infection. The loss of taste and smell sensation may negatively affect patients' quality of life (QoL). The present study aimed to evaluate the effectiveness of the Diode Laser in managing loss of taste sensation in patients with post-COVID syndrome versus the placebo. MATERIAL AND METHOD: The study sample was 36 patients who complained of persistent loss of taste sensation following COVID-19. The patients were randomly assigned to one of the two groups according to the received treatment: Group I (laser treatment) and Group II (light treatment), with each patient receiving a diode laser treatment or placebo from the same operator. Taste sensation was subjectively measured after treatment for four weeks. RESULTS: The results demonstrated a significant difference between both groups regarding taste restoration after one month (p = 0.041), with Group II having a significantly higher percentage of cases 7 (38.9%) with partial taste restoration. In contrast, a significantly higher proportion of Group I 17 cases (94.4%) had complete taste restoration (p < 0.001). CONCLUSION: The present study concluded that using a Diode laser 810 nm aided in a more rapid recovery from loss of taste dysfunction.

Intelligent optimization design of electron barrier layer for AlGaN-based deep-ultraviolet light-emitting diodes

AlGaN-based deep-ultraviolet light-emitting diodes (DUV LEDs) are widely used in sterilization, sensing,water purification, medical treatment, non-line of sight (NLOS) communication and many other fields.Especially it has been reported that the global novel coronavirus (COVID-19) can be effectively inactivated bythe DUV light with a wavelength below 280 nm (UVC) within a few seconds, which has also attracted greatattention. However, the external quantum efficiency (EQE) of UVC LED is still at a low level, generally notmore than 10%. As an important component of EQE, internal quantum efficiency (IQE) plays a crucial role inrealizing high-performance DUV-LED. In order to improve the IQE of AlGaN-based DUV-LED, this workadopts an electron blocking layer (EBL) structure based on InAlGaN/AlGaN superlattice. The results showthat the superlattice EBL structure can effectively improve the IQE compared with the traditional single-layerand double-layer EBL structure for the DUV-LED. On this basis, the optimization method based on JAYAintelligent algorithm for LED structure design is proposed in this work. Using the proposed design method, theInAlGaN/AlGaN superlattice EBL structure is further optimized to maximize the LED' s IQE. It isdemonstrated that the optimized superlattice EBL structure is beneficial to not only the suppression of electronleakage but also the improvement of hole injection, leading to the increase of carrier recombination in the activeregion. As a result, the IQE of the DUV-LED at 200 mA injection current is 41.2% higher than that of thesingle-layer EBL structure. In addition, the optimized structure reduces IQE at high current from 25% to 4%.The optimization method based on intelligent algorithm can break through the limitation of the current LEDstructure design and provide a new method to improve the efficiency of AlGaN-based DUV-LED.

Covid-19 Mppt Algorithm Application to Solar Energy Conversion System

Alternative energy alternatives to traditional energy sources like coal and fossil fuels include solar PV and wind energy conversion systems. The solar and wind energy conversion system's maximum power may be obtained by activating the converters. There are several MPPT (Maximum Power Point Tracking) regulating methods for solar and wind energy conversion systems. For solar PV energy conversion systems, this study suggests two MPPT controlling techniques: Covid-19 MPPT and FLC-based MPPT. The two MPPT methods that are suggested are put into practise using MATLAB. The first Covid-19 approach that has been developed combines aspects of hill climbing and progressive conductance methods. Calculate the direction of the perturbation for the PV modules' operation using the incremental conductance approach. The method of ascending hills is straightforward and involves fewer variables. When dI/dV equals the incremental conductance, the Maximum Power Point (MPP) is attained using the incremental conductance approach. In the hill climbing approach, the MPP is determined by comparing the power in the present and the past. Both incremental conductance and change of power are taken into account in the proposed Covid-19 MPPT regulating approach to obtain the MPP. With this hybrid approach, solar PV generates the most electricity possible under all conditions of temperature and irradiance. As a result, the planned Covid-19 technique moves forward as intended and swiftly reaches the MPP.Copyright © 2022, Anka Publishers. All rights reserved.

Investigation of Ultraviolet-C light-emitting diode for airborne disinfection in air duct

Given the current coronavirus (COVID-19) situation around the world, we may have to face a long-term battle with coronavirus. It is necessary to prepare and stay resilient with some other techniques to improve air quality in buildings, especially in clinics and hospitals. In this paper, we have developed Ultraviolet-C (UVC) light-emitting diode (LED) modules which can be implemented in air ducts in heating, ventilation, and air conditioning system for airborne disinfection. An LED module is designed with LED panels as the basic unit so that it is easy to scale up to accommodate for air ducts with different sizes. Both experiments and simulations are carried out to study its disinfection performance. The results show that more than 76% and 85% of the pathogen can be inactivated within 60 and 90 min, respectively, in a meeting room with a volume of 107 m3 by using one LED module. Simulations for two LED modules show that the disinfection efficacy is more than two times compared to that of one LED module. In addition to the pathogen used in the experiments, the disinfection performance of the LED module for inactivation of SARS-CoV-2 virus based on the literature is investigated numerically. It shows that more than 99.70% of pathogens receive UV dose larger than 4.47 J/m2, leading to an almost 89.10% disinfection rate for SARS-CoV-2 virus within one hour using the two LED modules in the same meeting room. © 2023 Author(s).

Design and Development of Polymer-Based Optical Fiber Sensor for GAIT Analysis

In the present scenario like COVID-19 pandemic, to maintain physical distance, the gait-based biometric is a must. Human gait identification is a very difficult process, but it is a suitable distance biometric that also gives good results at low resolution conditions even with face features that are not clear. This study describes the construction of a smart carpet that measures ground response force (GRF) and spatio-temporal gait parameters (STGP) using a polymer optical fiber sensor (POFS). The suggested carpet contains two light detection units for acquiring signals. Each unit obtains response from 10 nearby sensors. There are 20 intensity deviation sensors on a fiber. Light-emitting diodes (LED) are triggered successively, using the multiplexing approach that is being employed. Multiplexing is dependent on coupling among the LED and POFS sections. Results of walking experiments performed on the smart carpet suggested that certain parameters, including step length, stride length, cadence, and stance time, might be used to estimate the GRF and STGP. The results enable the detection of gait, including the swing phase, stance, stance length, and double supporting periods. The suggested carpet is dependable, reasonably priced equipment for gait acquisition in a variety of applications. Using the sensor data, gait recognition is performed using genetic algorithm (GA) and particle swarm optimization (PSO) technique. GA- and PSO-based gait template analyses are performed to extract the features with respect to the gait signals obtained from polymer optical gait sensors (POGS). The techniques used for classification of the obtained signals are random forest (RF) and support vector machine (SVM). The accuracy, sensitivity, and specificity results are obtained using SVM classifier and RF classifier. The results obtained using both classifiers are compared. © 2023 Mamidipaka Hema et al.

Intelligent optimization design of electron barrier layer for AlGaN-based deep-ultraviolet light-emitting diodes

AlGaN-based deep-ultraviolet light-emitting diodes (DUV LEDs) are widely used in sterilization, sensing, water purification, medical treatment, non-line of sight (NLOS) communication and many other fields. Especially it has been reported that the global novel coronavirus (COVID-19) can be effectively inactivated by the DUV light with a wavelength below 280 nm (UVC) within a few seconds, which has also attracted great attention. However, the external quantum efficiency (EQE) of UVC LED is still at a low level, generally not more than 10%. As an important component of EQE, internal quantum efficiency (IQE) plays a crucial role in realizing high-performance DUV-LED. In order to improve the IQE of AlGaN-based DUV-LED, this work adopts an electron blocking layer (EBL) structure based on InAlGaN/AlGaN superlattice. The results show that the superlattice EBL structure can effectively improve the IQE compared with the traditional single-layer and double-layer EBL structure for the DUV-LED. On this basis, the optimization method based on JAYA intelligent algorithm for LED structure design is proposed in this work. Using the proposed design method, the InAlGaN/AlGaN superlattice EBL structure is further optimized to maximize the LED' s IQE. It is demonstrated that the optimized superlattice EBL structure is beneficial to not only the suppression of electron leakage but also the improvement of hole injection, leading to the increase of carrier recombination in the active region. As a result, the IQE of the DUV-LED at 200 mA injection current is 41.2% higher than that of the single-layer EBL structure. In addition, the optimized structure reduces IQE at high current from 25% to 4%. The optimization method based on intelligent algorithm can break through the limitation of the current LED structure design and provide a new method to improve the efficiency of AlGaN-based DUV-LED. © 2023 Chinese Physical Society.

Solar desalination/purification (solar stills, humidification-dehumidification, solar disinfection) in high altitude during COVID19: Insights of gastrointestinal manifestations and systems' mechanism.

From the starting of the pandemic different transmission routes of the pathogen was brought into the spotlight by researchers from different disciplines. This matter in high-altitudes was more boosted as the main parameters were not exactly realized. In this review we are about to highlight the possibility of consuming contaminated water generated form solar water desalination/disinfection systems in highlands. Three systems including solar still, solar disinfection (which experimented by the authors in 2019 in high altitude) and humidification-dehumidification were consider in this context. Ascribe to the risks of pathogens transmission in solar desalination/disinfection systems where the water resources are heavily polluted in every corner of the world, highlighting the risk of consuming water in high-altitude where there are many other parameters associated with spread of pathogen is of great importance. As it was reported, reliability of solar desalination and solar water disinfections systems against contaminated water by the novel coronavirus remained on the question because the virus can be transmitted by vapor in solar stills due to tiny particle size (60-140 nm) and would not be killed by solar disinfections due to low-temperature of operation <40 °C while for HDH contamination of both water and air by sars-cov-2 could be a concern. Although the SARS-CoV-2 is not a waterborne pathogen, its capability to replicate in stomach and infection of gastrointestinal glandular suggested the potential of transmission via fecal-oral. Eventually, it was concluded that using solar-based water treatment as drinking water in high altitude regions should be cautiously consider and recommendations and considerations are presented. Importantly, this critical review not only about the ongoing pandemic, but it aims is to highlight the importance of produced drinking water by systems for future epidemic/pandemic to prevent spread and entering a pathogen particularly in high-altitude regions via a new routes.

COVID-19 pandemic lesson learned- critical parameters and research needs for UVC inactivation of viral aerosols.

The COVID-19 pandemic highlighted public awareness of airborne disease transmission in indoor settings and emphasized the need for reliable air disinfection technologies. This increased awareness will carry in the post-pandemic era along with the ever-emerging SARS-CoV variants, necessitating effective and well-defined protocols, methods, and devices for air disinfection. Ultraviolet (UV)-based air disinfection demonstrated promising results in inactivating viral bioaerosols. However, the reported data diversity on the required UVC doses has hindered determining the best UVC practices and led to confusion among the public and regulators. This article reviews available information on critical parameters influencing the efficacy of a UVC air disinfection system and, consequently, the required dose including the system's components as well as operational and environmental factors. There is a consensus in the literature that the interrelation of humidity and air temperature has a significant impact on the UVC susceptibility, which translate to changing the UVC efficacy of commercialized devices in indoor settings under varying conditions. Sampling and aerosolization techniques reported to have major influence on the result interpretation and it is recommended to use several sampling methods simultaneously to generate comparable and conclusive data. We also considered the safety concerns and the potential safe alternative of UVC, far-UVC. Finally, the gaps in each critical parameter and the future research needs of the field are represented. This paper is the first step to consolidating literature towards developing a standard validation protocol for UVC air disinfection devices which is determined as the one of the research needs.

Interest of drug checking supply: Results of 3 years of activity in Geneva

Aim: Swiss drug policy aims to reduce recreational drug consumption and its negative consequences. The strategy is based on a four pillars concept: prevention, therapy, harm reduction and repression. Among harm reduction programs drug checking (DC) facilities have emerged, allowing drug users to check the presence of adulterants or other non-expected substances, and to gain information concerning the purity of the product, without encouraging drug consumption. In 2019, one DC opened in Geneva (Switzerland) after receiving an authorization from the Federal Office of Public Health, and the results of 3 years of activity are presented. Method(s): Drug users brought samples anonymously to DC. Samples were send to the laboratory for analyses, and results are transmitted to DC, where drug users could obtained and discussed the results. Samples were dissolved in methanol, and a general unknown screening was performed by using gas chromatography coupled to mass spectrometry (GC-MS) directly and after acetylation. Depending of the substances, quantitative analyses were performed by using GC-MS, liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS), or liquid chromatography coupled to diode array detector (LC-DAD). Result(s): A total of 883 samples were analyzed from June 2019 to April 2022. The majority of samples were powders (67%), tablets (11%), plants (8%), and blotting papers (6%). For 71 samples (8%) the detected substances did not correspond to those announced by consumers, and in 23 samples (3%), no psychoactive substances were detected. Cocaine was detected in 290 samples (33%), with a median purity of 75%. In these samples, 11% contained also levamisole, 11% caffeine, and 7% phenacetin. Sympathomimetics were detected in 278 samples (31%). MDMA (16%), amphetamine (4.8%), 3-MMC (3.3%), 2C-B (2.6%), and 4-MMC (1.4%) were the most detected substances in this group of substances. MDMA was detected in powder specimen with a median purity of 85%, and in tablet form with a median amount of 133 mg (range: 3-320 mg). More rarely, methamphetamine, MDEA, 6-APB, 2C-D, 2C-E, BOD, 2-Br-4,5-DMPEA, DOB, DOC, DOM, MBDB, 3-FA, 5-MMPA, 5-MAPB, and 4-CMC were observed. Cannabinoids were detected in 84 samples (9.5%), and among these samples, 11 contained synthetic cannabinoids [5-Fluoro-MDMB-PINACA (3 cases);MDMB-4en-PINACA (8 cases)]. LSD and other hallucinogenic substances (1cP-LSD, psilocin, DMT, 4-ACO-DMT, 4-HO-MET) were detected in 85 samples (9.6%). Ketamine was detected in 68 cases (7.7%), with a median purity of 76%. Heroin was detected in 64 cases (7.2%), with a median purity of 20%. Benzodiazepines (alprazolam or etizolam) were detected in 7 cases (0.8%). The DC activity reached out to consumers who were not yet connected to prevention structures. The prevalence of the detected substances in the DC samples analyzed confirmed roughly what was known about the local market for illicit substances. However, some unexpected results were observed, such as the number of samples containing ketamine, or some new psychoactive substances. Interestingly, a couple of months after the beginning of COVID pandemic, 2 synthetic cannabinoids never detected before in Western Switzerland were observed, showing the interest of the DC facility in a harm reduction strategy, and more generally for public health prevention. Conclusion(s): Knowledge concerning the market of illicit psychoactive substances is complex and often difficult to assess. In this context, the analyses carried out for the Geneva DC have demonstrated a definite interest in better knowing and understanding the dynamics of the illicit substance market, complementing other information from police and customs seizures, wastewater analyses, used needle analyses, suspected DUID case analyses, clinical toxicology case analyses and postmortem case analyses. Copyright © 2022

Application of photobiomodulation therapy in acupuncture

Photobiomodulation (PBM) therapy is a therapeutic method that can produce a range of physiological effects in cells and tissues using certain wavelengths. The reparative benefits of PBM therapy include wound healing, bone regeneration, pain reduction, and the mitigation of inflammation. Advances in the development of laser instruments, including the use of high-intensity lasers in physiotherapy, have recently led to controllable photothermal and photomechanical treatments that enable therapeutic effects to be obtained without damaging tissue. The combination of PBM therapy with acupuncture may provide new perspectives for investigating the underlying therapeutic mechanisms of acupuncture and promote its widespread application.

Implication of cell culture methods and biases on UV inactivation of viruses.

Inactivation of human respiratory viruses in air and on surfaces is important to control their spread. Exposure to germicidal ultraviolet (UV-C) light damages viral nucleic acid rendering them non-infectious. Most of the recent viral inactivation studies have not considered potential artifacts caused by interactions between UV-C light and culture media used to suspend and deposit virus on surfaces. We show that the reactive oxygen and nitrogen species (ROS and RNS) form when commonly used virus culture media is exposed to 265 nm irradiation from light emitting diodes (LEDs) at UV-C doses (4 or 40 mJ/cm2) commonly considered to achieve multiple log-inactivation of virus. Surface viral inactivation values were enhanced from 0.49 to 2.92 log10 of viruses in DMEM, EMEM or EMEM-F as compared to absence of culture media (only suspended in Tris-buffer). The mechanisms responsible for the enhanced surface inactivate is hypothesized to involve photo-activation of vitamins and dyes present in the culture media, deposited with the virus on surfaces to be disinfected, which produce ROS and RNS. Given the rapidly growing research and commercial markets for UV-C disinfecting devices, there is a need to establish surface disinfecting protocols that avoid viral inactivation enhancement artifacts associated with selection and use of common cell culture media in the presence of UV-C light. This study addresses this weak link in the literature and highlights that inadequate selection of virus suspension media may cause a bias (i.e., over-estimation) for the UV-C dosages required for virus inactivation on surfaces.

The Wavelength-Based Inactivation Effects of a Light-Emitting Diode Module on Indoor Microorganisms.

With the increased incidence of infectious disease outbreaks in recent years such as the COVID-19 pandemic, related research is being conducted on the need to prevent their spread; it is also necessary to develop more general physical-chemical control methods to manage them. Consequently, research has been carried out on light-emitting diodes (LEDs) as an effective means of light sterilization. In this study, the sterilization effects on four types of representative bacteria and mold that occur indoors, Bacillus subtilis, Escherichia coli, Penicillium chrysogenum, and Cladosporium cladosporidides, were confirmed using LED modules (with wavelengths of 275, 370, 385, and 405 nm). Additionally, power consumption was compared by calculating the time required for 99.9% sterilization of each microorganism. The results showed that the sterilization effect was high, in the order 275, 370, 385, and 405 nm. The sterilization effects at 385 and 405 nm were observed to be similar. Furthermore, when comparing the power consumption required for 99.9% sterilization of each microorganism, the 275 nm LED module required significantly less power than those of other wavelengths. However, at 405 nm, the power consumption required for 99.9% sterilization was less than that at 370 nm; that is, it was more efficient and similar to or less than that at 385 nm. Additionally, because 405 nm can be applied as general lighting, it was considered to have wider applicability and utility compared with UV wavelengths. Consequently, it should be possible to respond to infectious diseases in the environment using LEDs with visible light wavelengths.

Smart Access Control System For Covid Safety Smart Access Control System during Covid

During the period of prevailing unsettled COVID pandemic, the countries and states started to plan reopening during which necessitates the non-contact temperature evaluation gadgets as a part of a preliminary look at access points to identify the humans with elevated body temperatures. Despite the utilization of these devices, temperature assessment restricted the impact on lowering the spread of COVID-19. Non-contact temperature measuring devices are used to measure the temperature of any person. Detection of a high temperature is one huge manner to pick out a person who might also have COVID-19 contamination. In this project, a room environment is created in which certain precautions are taken. A laser diode and receiver are used to detect the entrance of a person, and the system also detects the body temperature of the entering person. If the temperature is less than a threshold temperature entry for the person is permitted or else the entry is denied. This system also has a feature where it permits only a pre-determined number of persons inside the room. It also facilities to view the allowed temperature, the number of people to be allowed in the room and the number of people present actively using a Bluetooth App. This system aimed to be useful to combat the spread of COVID infections. © 2022 IEEE.

IoT-Galvanized pandemic special E-Toilet for generation of sanitized environment

The entire world is enmeshing the pandemic COVID-19, which affected the public health and it is spread all over the world. Every country’s authority is making more and more efforts towards maintaining the public health as well as mental health and are developing the vaccination to control the COVID-19. As COVID-19 is an infected disease for which a sanitized environment must be chosen at top most priority to prevent infection. Most of the countries are facing the problem of incrementing the infection rate of COVID due to griminess problems. Most healthcare industries are also working to create a sanitized environment with incorporation of the Internet of Things (IoT) which is resulting in the smart health care appliances for generating the sanitized environment. In this paper the researchers have developed an IoT- Galvanized Pandemic Special E-Toilet for generation of sanitized environment which resolves the issues of griminess problem. The proposed architecture has been comprising with three levels of working methodology as Occupancy Check, Auto Flush and Auto control of Appliances using Mobile Application. It is implemented using a raspberry pi board, Arduino Uno as a core unit of the system with interfacing the peripherals: IR sensor, Ultrasonic sensor and HC05 Bluetooth module, servo motor, Relay module, CFL lamp and LED. The proposed architecture has been simulated individually using single piece of sensor, then later assembled all the peripheral together and simulated. The proposed architecture can be used in field of education, industries, corporate offices, multiplexes, hospitals etc. [ FROM AUTHOR] Copyright of Journal of Discrete Mathematical Sciences & Cryptography is the property of Taylor & Francis Ltd and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full . (Copyright applies to all s.)

On the performance and reliability of state-of-the-art commercial UV-C LEDs for disinfection purposes

In the last year the market of ultraviolet (UV) light-emitting diodes (LEDs) had a huge increase due to the higher demand of devices caused by the pandemic crisis. In fact, it was demonstrated that UV LEDs, and in particular UV-B and UV-C LEDs, could be used as efficient sources for the disinfection of surfaces against Sars-CoV-2. In this work, we investigated electrical, optical and spectral degradation mechanisms in a series of commercial UV-C LEDs (275 nm - 280 nm) available on market. We present an exhaustive comparison of the main sample characteristics, studying their evolution when the LEDs are submitted to constant current stress tests (for about 350 h) at the absolute maximum current indicated in the respective datasheets. In particular, we carried out an extensive set of measurements, including current-voltage (I-V), optical power-current (L-I) and power spectral density (PSD) characteristics at various steps of stress, combined with the analysis of the drive voltage during the tests and of the thermal droop of the devices. We found: (i) a set of LEDs with a promising L80 of 10000 min (about 170 h), (ii) the presence of parasitic peaks and bands in all devices, ascribed to radiative recombination outside the QWs, and (iii) a substantial increase in thermal droop in all LEDs due to a decrease in injection efficiency and an increase in SRH recombination events during the stress tests. © 2022 SPIE. All rights reserved.

The Prevalence of Digital Eye Strain of Ukrainian Students and the Possibility of its Reduction

An analysis of the prevalence of Digital Eye Strain (DES) among Ukrainian students (320 students) during the COVID-19 pandemic was made. A comprehensive examination and treatment of 70 students (140 eyes) with to DES at the age of 18 to 25 years, was carried out. Group 1 consisted of 26 students (52 eyes) and group 2 – of 44 (88 eyes). All students underwent a course of laser stimulation (LS) using a diode laser (10 daily sessions were performed on a CM-4.3 device, λ=650 nm, W=0.4 mW/cm², t=300 s). The students of the 2 group were recommended additionally after LS to use for 3 months the vitamin-antioxidant complex Nutrof® Forte, 1 capsule once a day. The prevalence of Digital Eye Strain with more than 6 symptoms reaches 84.4% in this sample of students, which is associated with a young age (18–25 years old), hard and long visual work and active use of digital gadgets and computers during distance learning. This high prevalence of DES underlines the importance of awareness raising and encourages the introduction of targeted screening for DES among students. The course of treatment, including the intake of a vitamin-antioxidant complex of the AREDS formula with resveratrol and vitamin D3, can significantly improve visual acuity, increase accommodation reserves, reduce spasm of intraocular vessels by normalizing the balance of the functioning of the sympathetic and parasympathetic parts of the autonomic nervous system and significantly reduce or even eliminate the existing Digital Eye Strain symptoms. © 2021, Professionalnye Izdaniya. All rights reserved.

SpO2 Measurement: Non-Idealities and Ways to Improve Estimation Accuracy in Wearable Pulse Oximeters

The blood oxygen saturation level (SpO2) has become one of the vital body parameters for the early detection, monitoring, and tracking of the symptoms of coronavirus diseases 2019 (COVID-19) and is clinically accepted for patient care and diagnostics. Pulse oximetry provides non-invasive SpO2 monitoring at home and ICUs without the need of a physician/doctor. However, the accuracy of SpO2 estimation in wearable pulse oximeters remains a challenge due to various non-idealities. We propose a method to improve the estimation accuracy by denoising the red and IR signals, detecting the signal quality, and providing feedback to hardware to adjust the signal chain parameters like LED current or transimpedance amplifier gain and enhance the signal quality. SpO2 is calculated using the red and infrared photoplethysmogram (PPG) signals acquired from the wrist using Texas Instruments AFE4950EVM. We introduce the green PPG signal as a reference to obtain the window size of the moving average filter for baseline wander removal and as a timing reference for peak and valley detection in the red and infrared PPG signals. We propose the improved peak and valley detection algorithm based on the incremental merge segmentation algorithm. Kurtosis, entropy, and Signal-to-noise ratio (SNR) are used as signal quality parameters, and SNR is further related to the variance in the SpO2 measurement. A closed-loop implementation is performed to enhance signal quality based on the signal quality parameters of the recorded PPG signals. The proposed algorithm aims to estimate SpO2 with a variance of 1% for the pulse oximetry devices. IEEE

Rapid blood-oxygenation-saturation measurement using radially polarized light from light-emitting diodes

Photoplethysmography (PPG) is an optical technique that monitors oxygen saturation levels that is captured by pulse oximeters and some wearables such as smartwatches. The technique has been shown to overestimate oxyhemoglobin saturation in patients with darker skin, potentially leading to silent hypoxia and a disproportionately higher number of deaths in black and brown COVID-19 patients. We demonstrate a novel PPG technique that uses radially polarized light created by light-emitting diodes (LEDs) to address this problem. Our method performs single-shot, multiple polarization measurements using a single wavelength. We present a new use for vector-beams as well as the first demonstration of vector-beam generation using LEDs. © COPYRIGHT SPIE. Downloading of the is permitted for personal use only.

Benzene and NOx photocatalytic-assisted removal using indoor lighting conditions

Modern life-style is creating an indoor generation: human beings spend approximately 90% of their time indoors, almost 70% of which is at home – this trend is now exacerbated by the lockdowns/restrictions imposed due to the COVID-19 pandemic. That large amount of time spent indoors may have negative consequences on health and well-being. Indeed, poor indoor air quality is linked to a condition known as sick building syndrome. Therefore, breathing the freshest air possible is of outmost importance. Still, due to reduced ventilation rates, indoor air quality can be considerably worse than outdoor. Heating, ventilation, and air conditioning (HVAC), air filtration systems and a well-ventilated space are a partial answer. However, these approaches involve only a physical removal. The photocatalytic mineralization of pollutants into non-hazardous, or at least less dangerous compounds, is a more viable solution for their removal. Titanium dioxide, the archetype photocatalytic material, needs UVA light to be ‘activated’. However, modern household light emitting diode lamps irradiate only in the visible region of the solar spectrum. We show that the surface of titanium dioxide nanoparticles modified with copper oxide(s) and graphene has promise as a viable way to remove gaseous pollutants (benzene and nitrogen oxides) using a common light emitting diode bulb, mimicking real indoor lighting conditions. Titanium dioxide, modified with 1 mol% CuxO and 1 wt% graphene, proved to have a stable photocatalytic degradation rate, three times higher than that of unmodified titania. Materials produced in this research work are thus strong candidates for offering a safer indoor environment. © 2022 Elsevier Ltd