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1.
Sustainability ; 14(9):4954, 2022.
Article in English | ProQuest Central | ID: covidwho-1843009

ABSTRACT

Road transport is in most cases the only available transport option in rural regions with undeveloped railway infrastructure. The problem of choosing the structure of the logistics chain is one of the most important ones that forwarding companies must solve when planning freight transportation. Due to political peculiarities, transportation of goods by road through the territory of Kazakhstan must be carried out by national forwarders, which results in centralizing the decision-making process and shifting the tasks of designing the structure of supply chains to the Kazakh forwarding companies. In this paper, we develop a mathematical model to solve the problem of choosing the right structure for a logistics chain. The proposed model considers the existing legal constraints in the region. Based on a simulated demand for cargo deliveries from China to Russia, we use a numerical example to show how to justify the structure of the logistics chain characterized by minimal total costs of the companies involved in the delivery process.

2.
Mathematics ; 10(9):1366, 2022.
Article in English | ProQuest Central | ID: covidwho-1843006

ABSTRACT

In recent decades, AIDS has been one of the main challenges facing the medical community around the world. Due to the large human deaths of this disease, researchers have tried to study the dynamic behaviors of the infectious factor of this disease in the form of mathematical models in addition to clinical trials. In this paper, we study a new mathematical model in which the dynamics of CD4+ T-cells under the effect of HIV-1 infection are investigated in the context of a generalized fractal-fractional structure for the first time. The kernel of these new fractal-fractional operators is of the generalized Mittag-Leffler type. From an analytical point of view, we first derive some results on the existence theory and then the uniqueness criterion. After that, the stability of the given fractal-fractional system is reviewed under four different cases. Next, from a numerical point of view, we obtain two numerical algorithms for approximating the solutions of the system via the Adams-Bashforth method and Newton polynomials method. We simulate our results via these two algorithms and compare both of them. The numerical results reveal some stability and a situation of lacking a visible order in the early days of the disease dynamics when one uses the Newton polynomial.

3.
Atmospheric Chemistry and Physics ; 22(9):6291-6308, 2022.
Article in English | ProQuest Central | ID: covidwho-1842977

ABSTRACT

The Chinese government recently proposed ammonia (NH3) emission reductions (but without a specific national target) as a strategic option to mitigate fine particulate matter (PM2.5) pollution. We combined a meta-analysis of nationwide measurements and air quality modeling to identify efficiency gains by striking a balance between controlling NH3 and acid gas (SO2 and NOx) emissions. We found that PM2.5 concentrations decreased from 2000 to 2019, but annual mean PM2.5 concentrations still exceeded 35 µg m-3 at 74 % of 1498 monitoring sites during 2015–2019. The concentration of PM2.5 and its components were significantly higher (16 %–195 %) on hazy days than on non-hazy days. Compared with mean values of other components, this difference was more significant for the secondary inorganic ions SO42-, NO3-, and NH4+ (average increase 98 %). While sulfate concentrations significantly decreased over this period, no significant change was observed for nitrate and ammonium concentrations. Model simulations indicate that the effectiveness of a 50 % NH3 emission reduction for controlling secondary inorganic aerosol (SIA) concentrations decreased from 2010 to 2017 in four megacity clusters of eastern China, simulated for the month of January under fixed meteorological conditions (2010). Although the effectiveness further declined in 2020 for simulations including the natural experiment of substantial reductions in acid gas emissions during the COVID-19 pandemic, the resulting reductions in SIA concentrations were on average 20.8 % lower than those in 2017. In addition, the reduction in SIA concentrations in 2017 was greater for 50 % acid gas reductions than for the 50 % NH3 emission reductions. Our findings indicate that persistent secondary inorganic aerosol pollution in China is limited by emissions of acid gases, while an additional control of NH3 emissions would become more important as reductions of SO2 and NOx emissions progress.

4.
International Journal of Molecular Sciences ; 23(9):4485, 2022.
Article in English | ProQuest Central | ID: covidwho-1842816

ABSTRACT

Schizandrol A (SZA) and schizandrol B (SZB) are two active ingredients of Wuzhi capsule (WZC), a Chinese proprietary medicine commonly prescribed to alleviate tacrolimus (FK-506)-induced hepatoxicity in China. Due to their inhibitory effects on cytochrome P450 (CYP) 3A enzymes, SZA/SZB may display drug–drug interaction (DDI) with tacrolimus. To identify the extent of this DDI, the enzymes’ inhibitory profiles, including a 50% inhibitory concentration (IC50) shift, reversible inhibition (RI) and time-dependent inhibition (TDI) were examined with pooled human-liver microsomes (HLMs) and CYP3A5-genotyped HLMs. Subsequently, the acquired parameters were integrated into a physiologically based pharmacokinetic (PBPK) model to quantify the interactions between the SZA/SZB and the tacrolimus. The metabolic studies indicated that the SZB displayed both RI and TDI on CYP3A4 and CYP3A5, while the SZA only exhibited TDI on CYP3A4 to a limited extent. Moreover, our PBPK model predicted that multiple doses of SZB would increase tacrolimus exposure by 26% and 57% in CYP3A5 expressers and non-expressers, respectively. Clearly, PBPK modeling has emerged as a powerful approach to examine herb-involved DDI, and special attention should be paid to the combined use of WZC and tacrolimus in clinical practice.

5.
Journal of Clinical Laboratory Analysis ; 36(5), 2022.
Article in English | ProQuest Central | ID: covidwho-1842755

ABSTRACT

BackgroundThis study aimed to compare the testing strategies for COVID‐19 (i.e., individual, simple pooling, and matrix pooling) in terms of cost.MethodsWe simulated the total expenditures of each testing strategy for running 10,000 tests. Three parameters were used: positive rate (PR), pool size, and test cost. We compared the total testing costs under two hypothetical scenarios in South Korea. We also simulated country‐specific circumstances in India, South Africa, South Korea, the UK, and the USA.ResultsAt extreme PRs of 0.01% and 10%, simple pooling was the most economic option and resulted in cost reductions of 98.0% (pool size ≥80) and 36.7% (pool size = 3), respectively. At moderate PRs of 0.1%, 1%, 2%, and 5%, the matrix pooling strategy was the most economic option and resulted in cost reductions of 97.0% (pool size ≥88), 86.1% (pool size = 22), 77.9% (pool size = 14), and 59.2% (pool size = 7), respectively. In both hypothetical scenarios of South Korea, simple pooling costs less than matrix pooling. However, the preferable options for achieving cost savings differed depending on each country's cost per test and PRs.ConclusionsBoth pooling strategies resulted in notable cost reductions compared with individual testing in most scenarios pertinent to real‐life situations. The appropriate type of testing strategy should be chosen by considering the PR of COVID‐19 in the community and the test cost while using an appropriate pooling size such as five specimens.

6.
Atmospheric Chemistry and Physics ; 22(9):6151-6165, 2022.
Article in English | ProQuest Central | ID: covidwho-1841631

ABSTRACT

The COVID-19 (coronavirus disease 2019) European lockdowns have led to a significant reduction in the emissions of primary pollutants such as NO (nitric oxide) and NO2 (nitrogen dioxide). As most photochemical processes are related to nitrogen oxide (NOx≡ NO + NO2) chemistry, this event has presented an exceptional opportunity to investigate its effects on air quality and secondary pollutants, such as tropospheric ozone (O3). In this study, we present the effects of the COVID-19 lockdown on atmospheric trace gas concentrations, net ozone production rates (NOPRs) and the dominant chemical regime throughout the troposphere based on three different research aircraft campaigns across Europe. These are the UTOPIHAN (Upper Tropospheric Ozone: Processes Involving HOx and NOx) campaigns in 2003 and 2004, the HOOVN1 -https://media.proquest.com/media/hms/PFT/1/Q2apM?_a=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&_s=4R%2BrSLBAOWkAv60BD6umfsLkEuQ%3D

7.
Fractals ; : 1, 2022.
Article in English | Academic Search Complete | ID: covidwho-1840612

ABSTRACT

In this paper, the dynamical behavior of Middle East respiration syndrome coronavirus (MERS-CoV) via a sense of Caputo fractal-fractional order system of differential equation is established. A novel approach of fractional operator known as fractal-fractional Riemann–Liouville derivative is applied to the model considered. Moreover, fractal-fractional derivative is applied to the said problem. Furthermore, the existence and uniqueness of the solution of the considered model are verified by the fixed-point theory approach. The local and global stability of developed system are investigated with the help of the Ulam–Hyers stability technique from nonlinear functional analysis. The fractal-fractional type Adams–Bashforth iterative method is used to establish the numerical solution of said problem. The proposed model is simulated by considering different fractal dimensions (휃) and fractional order (δ), converging to the integer order. Hence, it is evident that all the compartmental quantities possess convergence and stability in fractal-fractional form. Moreover, the Fractal-fractional techniques may also be used as a powerful technique/tool to investigate the global dynamics of the disease. However, it can be concluded from the results that quick recovery is possible for human population in the pandemic if there is no animal interaction with humans. In future, we are planning to extend the reported analysis to other fractional (fractal-fractional) operators. Furthermore, the behavior of different infectious models can also be analyzed with the help of newly developed scheme at different fractional orders lying between 0 and 1. [ FROM AUTHOR] Copyright of Fractals is the property of World Scientific Publishing Company 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.)

8.
ACS Applied Electronic Materials ; 4(4):1732-1740, 2022.
Article in English | Scopus | ID: covidwho-1839488

ABSTRACT

Since its beginning, various countries have gone through multiple waves of surging COVID-19 infections. With the emergence of variants like Delta and Omicron, the disease is highly contagious and has the ability to spread at an alarming rate. In such scenarios, a quick and effective detection system is highly desirable. In this study, we present the concept of a surface plasmon resonance (SPR) based sensing system that can be utilized efficiently and reliably for the detection of SARS-CoV-2 antigens. The SPR system offers multiple advantages like real-time and label-free sensing of analytes and commercial systems have been in the market for more than two decades. Antireflective coatings (ARCs) have a number of application areas because of their unique properties. But they have seldom been used in the area of SPR sensing Hence, with the help of simulation, we make use of these coatings as intermediate layers and propose an enhanced sensing scheme by making use of ARCs of TiO2and SiO2and perovskite materials-BaTiO3, PbTiO3, and SrTiO3. We found that, using TiO2, SiO2, and PbTiO3, a maximum sensitivity of 392 degRIU-1can be obtained which is 5.29-fold enhancement as compared to the standard SPR arrangement using gold. © 2022 ACS Applied Electronic Materials. All right reserved.

9.
Embase; 2022.
Preprint in English | EMBASE | ID: ppcovidwho-336002

ABSTRACT

Objective: To evaluate the benefits of vaccination on the case fatality rate (CFR) for COVID-19 infections. Design: Multivariate modeling of data from electronic medical records Setting: 130 medical centers of the United States Department of Veterans Affairs Participants: 339,772 patients with COVID-19 confirmed by nucleic acid amplification testing as of September 30, 2021 Methods: The primary outcome was death within 60 days of the diagnosis. Patients were considered vaccinated if they had completed a full series >= 14 days prior to diagnosis. Cases presenting in July - September of 2021 were considered to have the delta variant. Logistic regression was used to derive adjusted odds ratios (OR) for vaccination and infection with delta versus earlier variants. Models were adjusted for demographic traits, standard comorbidity indices, selected clinical terms, and 3 novel parameters representing all prior diagnoses, all prior vital signs/baseline laboratory tests, and current outpatient treatment. Patients with a delta infection were divided into 8 cohorts based upon the time from vaccination to diagnosis (in 4-week blocks). A common model was used to estimate the odds of death associated with vaccination for each cohort relative that of all unvaccinated patients. Results: 9.1% of subjects had been fully vaccinated, and 21.5% were presumed to have the delta variant. 18,120 patients (5.33%) died within 60 days of their diagnoses. The adjusted OR for delta infection was 1.87 +/- 0.05 which corresponds to a relative risk of 1.78. The overall adjusted OR for prior vaccination was 0.280 +/- 0.011 corresponding to a relative risk of 0.291. The study of vaccine cohorts with a delta infection showed that the raw CFR rose steadily after 10-14 weeks. However, the OR for vaccination remained stable for 10-34 weeks. Conclusions: Our study confirms that delta is substantially more lethal than earlier variants and that vaccination is an effective means of preventing COVID death. After adjusting for major selection biases, we found no evidence that the benefits of vaccination on CFR declined over 34 weeks.

10.
Embase; 2021.
Preprint in English | EMBASE | ID: ppcovidwho-335896

ABSTRACT

Background: Despite the vaccination process in Germany, a large share of the population is still susceptible to SARS-CoV-2. In addition, we face the spread of novel variants. Until we overcome the pandemic, reasonable mitigation and opening strategies are crucial to balance public health and economic interests. Methods: We model the spread of SARS-CoV-2 over the German counties by a graph-SIR-type, metapopulation model with particular focus on commuter testing. We account for political interventions by varying contact reduction values in private and public locations such as homes, schools, workplaces, and other. We consider different levels of lockdown strictness, commuter testing strategies, or the delay of intervention implementation. We conduct numerical simulations to assess the effectiveness of the different intervention strategies after one month. The virus dynamics in the regions (German counties) are initialized randomly with incidences between 75-150 weekly new cases per 100,000 inhabitants (red zones) or below (green zones) and consider 25 different initial scenarios of randomly distributed red zones (between 2 and 20 % of all counties). To account for uncertainty, we consider an ensemble set of 500 Monte Carlo runs for each scenario. Results: We find that the strength of the lockdown in regions with out of control virus dynamics is most important to avoid the spread into neighboring regions. With very strict lockdowns in red zones, commuter testing rates of twice a week can substantially contribute to the safety of adjacent regions. In contrast, the negative effect of less strict interventions can be overcome by high commuter testing rates. A further key contributor is the potential delay of the intervention implementation. In order to keep the spread of the virus under control, strict regional lockdowns with minimum delay and commuter testing of at least twice a week are advisable. If less strict interventions are in favor, substantially increased testing rates are needed to avoid overall higher infection dynamics. Conclusions: Our results indicate that local containment of outbreaks and maintenance of low overall incidence is possible even in densely populated and highly connected regions such as Germany or Western Europe. While we demonstrate this on data from Germany, similar patterns of mobility likely exist in many countries and our results are, hence, generalizable to a certain extent.

11.
Embase; 2021.
Preprint in English | EMBASE | ID: ppcovidwho-335857

ABSTRACT

Contact tracing, where exposed individuals are followed up to break ongoing transmission chains, is a key pillar of outbreak response for infectious disease outbreaks. Unfortunately, these systems are not fully effective, and infections can still go undetected as people may not remember all their contacts or contacts may not be traced successfully. A large proportion of undetected infections suggests poor contact tracing and surveillance systems, which could be a potential area of improvement for a disease response. In this paper, we present a method for estimating the proportion of infections that are not detected during an outbreak. Our method uses next generation matrices that are parameterized by linked contact tracing data and case line-lists. We validate the method using simulated data from an individual-based model and then investigate two case studies: the proportion of undetected infections in the SARS-CoV-2 outbreak in New Zealand during 2020 and the Ebola epidemic in Guinea during 2014. We estimate that only 5.26% of SARS-CoV-2 infections were not detected in New Zealand during 2020 (95% credible interval: 0.243 - 16.0%) but depending on assumptions 39.0% or 37.7% of Ebola infections were not detected in Guinea (95% credible intervals: 1.69 - 87.0% or 1.7 - 80.9%).

12.
Embase; 2021.
Preprint in English | EMBASE | ID: ppcovidwho-335847

ABSTRACT

Low- and middle-income countries (LMICs) remain of high potential for hotspots for COVID-19 deaths and emerging variants given the inequality of vaccine distribution and their vulnerable healthcare systems. We aim to evaluate containment strategies that are sustainable and effective for LMICs. We constructed synthetic populations with varying contact and household structures to capture LMIC demographic characteristics that vary across communities. Using an agent-based model, we explored the optimal containment strategies for rural and urban communities by designing and simulating setting-specific strategies that deploy rapid diagnostic tests, symptom screening, contact tracing and physical distancing. In low-density rural communities, we found implementing either high quality (sensitivity > 50%) antigen rapid diagnostic tests or moderate physical distancing could contain the transmission. In urban communities, we demonstrated that both physical distancing and case finding are essential for containing COVID-19 (average infection rate < 10%). In high density communities that resemble slums and squatter settlements, physical distancing is less effective compared to rural and urban communities. Lastly, we demonstrated contact tracing is essential for effective containment. Our findings suggested that rapid diagnostic tests could be prioritised for control and monitor COVID-19 transmission and highlighted that contact survey data could guide strategy design to save resources for LMICs. An accompanying open source R package is available for simulating COVID-19 transmission based on contact network models.

13.
Embase; 2021.
Preprint in English | EMBASE | ID: ppcovidwho-335732

ABSTRACT

Background Mass community testing for SARS-CoV-2 by lateral flow devices (LFDs) aims to reduce prevalence in the community. However its effectiveness as a public heath intervention is disputed. Method Data from a mass testing pilot in the Borough of Merthyr Tydfil in late 2020 was used to model cases, hospitalisations, ICU admissions and deaths prevented. Further economic analysis with a healthcare perspective assessed cost-effectiveness in terms of healthcare costs avoided and QALYs gained. Results An initial conservative estimate of 360 (95% CI: 311-418) cases were prevented by the mass testing, representing a would-be reduction of 11% of all cases diagnosed in Merthyr Tydfil residents during the same period. Modelling healthcare burden estimates that 24 (16 - 36) hospitalizations, 5 (3-6) ICU admissions and 15 (11-20) deaths were prevented, representing 6.37%, 11.1% and 8.2%, respectively of the actual counts during the same period. A less conservative, best-case scenario predicts 2333 (1764-3115) cases prevented, representing 80% reduction in would-be cases. Cost effectiveness analysis indicates 108 (80-143) QALYs gained, an incremental cost ratio of £2,143 (£860-£4,175) per QALY gained and net monetary benefit of £6.2m (£4.5m-£8.4m). In the best-case scenario, this increases to £15.9m (£12.3m-£20.5m). Conclusions A non-negligible number of cases, hospitalisations and deaths were prevented by the mass testing pilot. Considering QALYs gained and healthcare costs avoided, the pilot was cost-effective. These findings suggest mass testing with LFDs in areas of high prevalence (>2%) is likely to provide significant public health benefit. It is not yet clear whether similar benefits will be obtained in low prevalence settings or with vaccination rollout.

14.
Embase; 2022.
Preprint in English | EMBASE | ID: ppcovidwho-335650

ABSTRACT

BACKGROUND Debate about the level of asymptomatic severe acute respiratory syndrome coronavirus 2 (SARSCoV-2) infection continues. The amount of evidence is increasing and study designs have changed over time. We updated a living systematic review to address three questions: (1) Amongst people who become infected with SARS-CoV-2, what proportion does not experience symptoms at all during their infection? (2) What is the infectiousness of asymptomatic and presymptomatic, compared with symptomatic, SARS-CoV-2 infection? (3) What proportion of SARS-CoV-2 transmission in a population is accounted for by people who are asymptomatic or presymptomatic? METHODS AND FINDINGS The protocol was first published on 1 April 2020 and last updated on 18 June 2021. We searched PubMed, Embase, bioRxiv and medRxiv, aggregated in a database of SARS-CoV-2 literature, most recently on 6 July 2021. Studies of people with PCR-diagnosed SARS-CoV-2, which documented symptom status at the beginning and end of follow-up, or mathematical modelling studies were included. Studies restricted to people already diagnosed, of single individuals or families, or without sufficient follow-up were excluded. One reviewer extracted data and a second verified the extraction, with disagreement resolved by discussion or a third reviewer. Risk of bias in empirical studies was assessed with a bespoke checklist and modelling studies with a published checklist. All data syntheses were done using random effects models. Review question (1): We included 130 studies. Heterogeneity was high so we did not estimate a mean proportion of asymptomatic infections overall (interquartile range 14-50%, prediction interval 2-90%), or in 84 studies based on screening of defined populations (interquartile range 20-65%, prediction interval 4-94%). In 46 studies based on contact or outbreak investigations, the summary proportion asymptomatic was 19% (95% CI 15-25%, prediction interval 2-70%). (2) The secondary attack rate in contacts of people with asymptomatic infection compared with symptomatic infection was 0.32 (95% CI 0.16-0.64, prediction interval 0.11-0-95, 8 studies). (3) In 13 modelling studies fit to data, the proportion of all SARS-CoV-2 transmission from presymptomatic individuals was higher than from asymptomatic individuals. Limitations of the evidence include high heterogeneity and high risks of selection and information bias in studies that were not designed to measure persistently asymptomatic infection, and limited information about variants of concern or in people who have been vaccinated. CONCLUSIONS Based on studies published up to July 2021, most SARS-CoV-2 infections were not persistently asymptomatic and asymptomatic infections were less infectious than symptomatic infections. Summary estimates from meta-analysis may be misleading when variability between studies is extreme and prediction intervals should be presented. Future studies should determine the asymptomatic proportion of SARS-CoV-2 infections caused by variants of concern and in people with immunity following vaccination or previous infection. Without prospective longitudinal studies with methods that minimise selection and measurement biases, further updates with the study types included in this living systematic review are unlikely to be able to provide a reliable summary estimate of the proportion of asymptomatic infections caused by SARS-CoV-2.

15.
J Food Biochem ; : e14219, 2022 May 11.
Article in English | MEDLINE | ID: covidwho-1840460

ABSTRACT

The current COVID-19 pandemic is severely threatening public healthcare systems around the globe. Some supporting therapies such as remdesivir, favipiravir, and ivermectin are still under the process of a clinical trial, it is thus urgent to find alternative treatment and prevention options for SARS-CoV-2. In this regard, although many natural products have been tested and/or suggested for the treatment and prophylaxis of COVID-19, carotenoids as an important class of natural products were underexplored. The dietary supplementation of some carotenoids was already suggested to be potentially effective in the treatment of COVID-19 due to their strong antioxidant properties. In this study, we performed an in silico screening of common food-derived carotenoids against druggable target proteins of SARS-CoV-2 including main protease, helicase, replication complex, spike protein and its mutants for the recent variants of concern, and ADP-ribose phosphatase. Molecular docking results revealed that some of the carotenoids had low binding energies toward multiple receptors. Particularly, crocin had the strongest binding affinity (-10.5 kcal/mol) toward the replication complex of SARS-CoV-2 and indeed possessed quite low binding energy scores for other targets as well. The stability of crocin in the corresponding receptors was confirmed by molecular dynamics simulations. Our study, therefore, suggests that carotenoids, especially crocin, can be considered an effective alternative therapeutics and a dietary supplement candidate for the prophylaxis and treatment of SARS-CoV-2. PRACTICAL APPLICATIONS: In this study, food-derived carotenoids as dietary supplements have the potential to be used for the prophylaxis and/or treatment of SARS-CoV-2. Using in silico techniques, we aimed at discovering food-derived carotenoids with inhibitory effects against multiple druggable sites of SARS-CoV-2. Molecular docking experiments against main protease, helicase, replication complex, spike protein and its mutants for the recent variants of concern, and ADP-ribose phosphatase resulted in a few carotenoids with multitarget inhibitory effects. Particularly, crocin as one of the main components of saffron exhibited strong binding affinities to the multiple drug targets including main protease, helicase, replication complex, mutant spike protein of lineage B.1.351, and ADP-ribose phosphatase. The stability of the crocin complexed with these drug targets was further confirmed through molecular dynamics simulations. Overall, our study provides the preliminary data for the potential use of food-derived carotenoids, particularly crocin, as dietary supplements in the prevention and treatment of COVID-19.

16.
Perfusion ; : 2676591221093868, 2022 May 11.
Article in English | MEDLINE | ID: covidwho-1840789

ABSTRACT

BACKGROUND: Extracorporeal membrane oxygenation (ECMO) is a supportive therapy used in the most severe forms of acute respiratory distress syndrome. Due to its intrinsic complexity and relatively low annual volume, simulation is essential for efficient and appropriate ECMO management. COVID-19 has limited the opportunities for high-fidelity in-person simulation training when many hospitals are looking to expand their ECMO services to battle the ongoing pandemic. To meet this demand, the National Cardiovascular Center Harapan Kita, Jakarta, Indonesia, conducted a 3-day ECMO course entailing online didactic lectures (adult and paediatric stream), water drills and telesimulation. PURPOSE: The purpose of the study is to report the evaluation result of this novel model of education during COVID-19 outbreak. DATA COLLECTION: Participants were given an ECMO knowledge pre-course and post-course test and a telesimulation evaluation survey at the conclusion and these data were collected. RESULTS: The course was attended by 104 physicians, critical care nurses and perfusionists. Pre-course and post-course assessments showed a significant improvement in ECMO knowledge (60.0% vs 73.3%, respectively). Overall, the participants rated the telesimulation positively, and most found it acceptable to in-person simulation training considering the pandemic restrictions. CONCLUSION: Despite the complexities of ECMO, our recent experience demonstrates ECMO education and simulation delivered online is feasible, welcomed and supportive of a change in ECMO training course format. As we incorporate more innovative digital technologies, telesimulation may further enhance the quality of future ECMO training.

17.
Applied Sciences ; 12(9):4255, 2022.
Article in English | ProQuest Central | ID: covidwho-1837989

ABSTRACT

The spread of emerging self-limiting infectious diseases is closely related to medical resources. This paper introduces the concept of safe medical resources, i.e., the minimum medical resources that are needed to prevent the overburden of medical resources, and explores the impacts of medical resources on the spread of emerging self-limiting infectious diseases. The results showed that when the isolation rate of hospitalized patients who have mild infections is low, increasing the isolation rate of patients with severe infections requires safe more medical resources. On the contrary, when the isolation rate of hospitalized patients with mild infections is at a high level, increasing the isolation rate of patients with severe infections results in a decrease in safe medical resources. Furthermore, when the isolation rates of patients with mild and severe infections increase simultaneously, safe medical resources decrease gradually. That is to say, when the medical resources are at a low level, it is more necessary to improve the isolation rates of infected individuals so as to avoid the phenomenon of overburdened medical resources and control the spread of emerging infectious diseases. In addition, overwhelmed medical resources increase the number of deaths. Meanwhile, for different emerging self-limiting infectious diseases, as long as the recovery periods are the same, safe medical resources also remain the same.

18.
Applied Sciences ; 12(9):4308, 2022.
Article in English | ProQuest Central | ID: covidwho-1837824

ABSTRACT

With the rapid expansion of prefabricated construction in China, significant changes in safety performance are still unapparent for numerous prefabricated constructions, and safety accidents are constantly exposed in public. The ignorance of interactions among safety risks impedes efficacious improvement, which instructs the need for a thorough analysis of these interactions based on complex network theory. This paper starts with the identification of 37 safety risks refined through literature review and expert interviews, and 90 interrelationships among them verified by virtue of the questionnaire survey, laying a foundation for the establishment of a prefabricated construction safety risk network (PCSRN). The topological analysis results prove that PCSRN is a scale-free as well as a small-world network, which indicates the high-efficiency propagation and diffusion among safety risks in prefabricated constructions. Moreover, eight critical nodes are identified with four different ranking criteria, and corresponding safety strategies are proposed to address them. The developed method not only provides a novel insight to interpret the safety risks of prefabricated construction but also has the potential to advance safety performance of this sector.

19.
International Journal of Electrical and Computer Engineering ; 11(5):3828-3837, 2021.
Article in English | ProQuest Central | ID: covidwho-1837763

ABSTRACT

In 2020 the COVID-19 pandemic has suddenly stopped society and changed human interaction. In this work, a thermoelectric generator wearable device for early fever detection symptoms is presented as a possible solution to avoid higher propagation of this disease. To identify a possible fever symptom, numerical and parametric simulations are developed using a highquality-refined hexahedral mesh. At first, a 2-pair-leg thermoelectric module has undergone simulations to establish temperature conditions, open-circuit voltage, and power output generation;and secondly, these previous results are extrapolated for a larger thermoelectric module containing 28 pair-leg of N-P type material. The numerical study shows that a maximum value of electrical power of 60.70 mW was reached for 28-pair-leg N-P type thermocouples under a constant temperature difference of 20 K.

20.
Mathematics ; 10(9):1459, 2022.
Article in English | ProQuest Central | ID: covidwho-1837595

ABSTRACT

This paper presents a solution for the modelling, implementation and simulation of the fractional-order process of producing the enriched 13C isotope, through the chemical exchange between carbamate and carbon dioxide. To achieve the goal of implementation and simulation of the considered process, an original solution for the approximation of fractional-order systems at the variation of the system’s differentiation order is proposed, based on artificial intelligence methods. The separation process has the property of being strongly non-linear and also having fractional-order behaviour. Consequently, in the implementation of the mathematical model of the process, the theory associated with the fractional-order system’s domain has to be considered and applied. For learning the dynamics of the structure parameters of the fractional-order part of the model, neural networks, which are associated with the artificial intelligence domain, are used. Using these types of approximations, the simulation and the prediction of the produced 13C isotope concentration dynamics are made with high accuracy. In order to prove the efficiency of the proposed solutions, a comparation between the responses of the determined model and the experimental responses is made. The proposed model implementation is made based on using four trained neural networks. Moreover, in the final part of the paper, an original method for the online identification of the separation process model is proposed. This original method can identify the process of fractional differentiation order variation in relation to time, a phenomenon which is quite frequent in the operation of the real separation plant. In the last section of the paper, it is proven that artificial intelligence methods can successfully sustain the system model in all the scenarios, resulting in the feasible premise of designing an automatic control system for the 13C isotope concentration, a method which can be applied in the case of other industrial applications too.

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