Fourth Peak Research Articles

Latent class analysis of hospitalization, ICU admission, and mortality among COVID-19 patients in Iran

Identifying COVID-19 patients’ clinical phenotypes based on characteristics and comorbidities, as well as their differences, helps in terms of clinical care and potential crises. Our goal is to use Latent Class Analysis (LCA) to identify COVID-19 patient profiles based on demographics, symptoms, and comorbidities, and evaluate their correlation with ICU admission, hospitalization duration, and mortality in a cross-sectional study. We included hospitalized patients with positive SARS-CoV-2 tests in two referral hospitals in the south of Iran between January 2020 and July 2021. Data from 7,968 patients were evaluated in two time-specific intervals, known as “stratum,” based on the point at which the COVID-19 fourth peak and vaccinations were nearly initiated. After applying LCA, three classes identified the most at-risk individuals, including elderly women with hypertension, diabetes, and heart disease, and elderly men with heart and lung conditions, compared to two classes of healthier, younger individuals. Hospital stays were longer in the first stratum compared with the second (P-value = 0.043). ICU admission during the first stratum was significantly higher than in the second stratum (P < 0.001) and lower in classes one and two in the first stratum compared to class three (reference class). Mortality rates were not significantly different between strata (P = 0.054). Hospital stays and mortality rates significantly differed between the classes in each first and second stratum (P < 0.001). Using LCA to investigate COVID-19 patients has provided valuable insights into different patterns and outcomes of the disease. Patient variables, including age, gender, and comorbidities, were associated with greater mortality and ICU admission, which can assist in resource allocation and vaccination planning.

Performance of limestone calcined clay cement (LC3) made with CO2-mineralized concrete slurry waste

Concrete slurry waste (CSW) is an under-recycled material with great potential to be substitute ordinary Portland cement (OPC) after proper treatment. In this study, dehydrated CSW (DCSW) was used to mineralize CO2 and the carbonated product was used to prepare limestone calcined clay cement (LC3). The results showed that the CaCO3 content of carbonated DCSW (CDCSW) reached ∼57.7% after mineralization for 8.5 h. During carbonation the Portlandite peak disappeared after 1.5 h, and the Mc_AFm peak disappeared after 3.5 h. The alite and belite peaks gradually diminished, with a weak diffraction remaining at 8.5 h. Replacing limestone with CDCSW led to a decrease of 14.7% in fluidity, at a plasticizer dosage of 1.3%. The compressive strength of LC3-cdcsw mortar specimens was higher than those of LC3-limestone specimens at all ages. The effective chloride diffusion coefficient of LC3-cdcsw was also promisingly small (1.08 × 10−11 m2/s). The comprehensive properties (grey correlation degree) of LC3-cdcsw were 17.82% lower than that of OPC, but 17.73% higher than that of ordinary LC3. At 28 d, the contents of monocarboaluminate for LC3-cdcsw and LC3-limestone are 11.2% and 9.5%, respectively. The fourth thermal decomposition peak of LC3 system is higher than that of OPC, and the peak intensity of LC3-cdcsw is lower than that of LC3-limestone. Our work explores the pathway of carbon sequestration in concrete slurry waste for the preparation low-carbon and durable cementitious materials.

Examining the detectability of ringing on highly eccentric exoplanets

Context. Eccentric exoplanets offer an opportunity to study the response of an atmosphere to changing thermal forcing and the robustness of the super-rotating equatorial jet seen on tidally locked hot Jupiters. However, the atmospheric dynamics on eccentric planets strongly depend on the planetary rotation period, which is difficult to constrain observationally. The ringing phenomenon, whereby the observed emission increases and decreases after the periastron passage as the flash-heated hemisphere rotates into and out of view, can provide a tight constraint on rotation. Aims. We studied five highly eccentric transiting exoplanets HAT-P-2 b, HD 80606 b, TOI-3362 b, TOI-4127 b and HD 17156 b to find which displays strong ringing signals that are sufficiently strong for the James Webb Space Telescope (JWST) to detect. Methods. We implemented the treatment of eccentricity and non-synchronous rotation in the non-grey climate model expeRT/MITgcm and generated synthetic light curves. Results. We find four detectable ringing peaks on HD 80606 b and some undetectable ringing on TOI-4127 b and HD 17156 b. The lack of clouds, photo-chemistry and obliquity in our models may have led us to overestimate the amplitude of the ringing however. The strength of the ringing signal is mostly determined by the eccentricity, planetary rotation period, planet-to-star radius ratio and apparent magnitude of the system. We searched for more exoplanets that could show ringing but found no candidates as promising as HD 80606 b. Conclusions. We recommend prioritising HD 80606 b as a target for ringing with JWST. A baseline of five days after the periastron passage would capture three ringing peaks, which is sufficient to tightly constrain the planetary rotation period. An extension to seven days would add a fourth peak, which would allow us to verify the rotation period.

A hybrid network with DNN and WGAN for supercontinum prediction

In this paper, a Hybrid Network is reported for predicting the output pulse shape parameters of the supercontinuum in optical fibers. The network incorporates the Wasserstein generative adversarial network (WGAN) and the deep neural network (DNN) with a TCN layer. The WGAN augments a limited set of original data, while the designed DNN accurately predicts supercontinuum. The simulation results show the spectra agreement (Agm) of the predictions by individual DNN is 89% and the root mean square error (RMSE) is 0.1092. After retraining with WGAN's extended dataset, the Agm of DNN predictions is improved to 98% and the RMSE is reduced to 0.0513. The input pump power corresponding to the appearance of the fourth soliton peak can be predicted by the retrained DNN. Numerical analysis demonstrates the effectiveness and generalization ability of a Hybrid Network in predicting pulse parameters. The network fits the propagation dynamics in the spectral domain of SC, which provides a promising tool for further research in this field.

Studies on the Malting Parameters of Two Acha Species Digitaria exilis and Digitaria iburua

The malting parameters of two acha species (Digitaria exilis-white and Digitaria iburua-black), a small annual herbaceous indigenous African cereal grain were studied. This study was aimed at assessing the brewing potential of the two acha species. The research was carried out in Microbiology Laboratory of Nnamdi Azikiwe University, Awka. The brewing properties assessed were; moisture content, cold water extract, hot water extract, diastatic power, total nitrogen, cold water soluble protein, total soluble protein and free amino nitrogen. Extraction, digestion, titration, colorimetric and spectrophotometric methods were used to assess the above brewing properties. The moisture content of the white species malt (11.0 - 12.4%) was higher than that of the black (10.3 – 11.2%) and increased with germination time but decreased after the peak (4th) day. The lower moisture content of the black acha malts gave a resultant effect of more extract production from cold water extract ( CWE 27.5, 30.10%), hot water extract (HWE 278, 304ol/kg) and diastatic power (DP 19 ,23oL) of the two acha malts on the fourth (peak) day of germination. The peak values for total nitrogen (1.6, 1.75%), cold water soluble protein (120, 128%), total soluble protein (6.2, 7.5%) and free amino nitrogen (FAN 105, 114.5%) were also higher for the black acha on the peak day of germination. The correlation studies between the HWE (R2=0.9903, 0.9551), Cold water soluble protein (CWS-P- R2= 0.9809, 0.9285) and Diastatic power for the black and white species, respectively, were positively significant depicting a strong relationship between the correlated parameters. The black acha malt recorded more extract yield than the white acha and the result of the two acha species assessed showed that they possess brewing properties.

Hepatoprotective effect of protein extract of the Potamogeton perfoliatus L. against carbon-tetrachloride-induced hepatic injury in mice

This article demonstrates the hepatoprotective action of the protein extract of the aquatic plant Potamogeton perfoliatus L. based on the histopathologic changes in the liver of mice with CCl4-induced liver damage. Using the chromatography, 4 fractions of the protein extract were obtained. It has been suggested that a fourth fraction corresponding to low molecular weight protein should most likely exhibit hepatoprotective properties. SDS-PAGE of P. perfoliatus L. revealed a protein with molecular weight of 21 kDa corresponding to the fourth peak of a chromatogram.

Difference in impact on emergency department visits following four major peaks of COVID-19 cases

Objective: Several variants of SARS-CoV-2 have emerged since its first appearance in 2019, greatly impacting healthcare systems across the globe. Previous literature indicated a substantial decline in emergency department (ED) visits in hospitals since the start of the COVID-19 pandemic. However, little research has been done to compare different variants’ (Ancestral, Alpha, Delta, Omicron, etc.) impact on patients presenting to the ED. Thus, the purpose of this retrospective observational study is to compare the changes in total ED volume following four major peaks of SARS-CoV-2 infection within a multi-hospital health system.Methods: Utilizing electronic healthcare record (EHR) data, total ED visits (484,268) and COVID-19 case counts (24,358) were collected and analyzed to compare ED census and COVID-19 trends across four years and four variant peak periods, from January 2019 to June 2022.Results: Results showed that ED visits declined after the first two major peaks (Ancestral and Alpha) in COVID-19 cases, which was consistent with national trends and prevailing literature. In contrast, ED visits increased following the fourth major peak (Omicron) in COVID-19 cases.Conclusions: The increase in ED visits following the fourth major peak was inconsistent with previous literature and trends. This may be attributed to the severity differences between variants, increased vaccination uptake, newly adopted public countermeasures, and evolving perceptions of safety and fear regarding COVID-19. These results underscore the critical importance for health administrators and policy planners to be cognizant of new strategies that alleviate barriers to receiving emergency care, especially during times of crisis.

A negative stiffness structure with multi-stable characteristic

This work proposes a straw-shaped structure (SS) inspired by the folds of straw. Two samples named SSⅠ and SSⅡ with 5 and 5.5 layers of conical structures, respectively, are prepared using selective laser sintering (SLS) technology. SSⅠ and SSⅡ can spontaneously recover to their original shapes after compression experiments. With the thickness of 0.6 and 3.0 mm for the upper and lower parts of cells, the peak and valley forces of SSII (SS-3.0-0.6) during compression and tension alternate periodically. The first and second valley forces of SS-3.0-0.6 are −16.1 and −20.2 N during compression, and its second, fifth and fourth peak forces are 30.2, 4.3 and 0.8 N during tension. SS-3.0-0.6 exhibits significant NS and multi-stable properties in both compression and tension, and it is easier to be stretched than compressed. The deformation mode of the folded structure is similar to stacked porcelain bowls. Through a reasonable design of geometric parameters, the folding order and deformation mode as well as the number of stable state of the SSII models can be customized. In addition, the potential applications of SSs are also discussed, and this work provides a valuable reference for the study of NS structures.

MgCl2-MXene based nanohybrid composite for efficient thermochemical heat storage application

Thermochemical heat storage is a practical approach for overcoming the challenge in solar energy applications. Herein, we synthesize a novel MgCl2/MXene (Ti3C2Tx) composite sorbent by impregnation method for low-temperature thermochemical heat storage application. Various techniques, including Thermogravimetric coupled with Differential Scanning Calorimetric (TG-DSC), X-Ray, Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM) were applied to characterize the mechanical and thermal properties of MgCl2/MXene composites. The result showed that Ti3C2Tx possess a larger specific surface area and the hydrophilic groups allow maximum MgCl2 adsorption without structural distortion. The TG-DSC studies showed that the fourth DSC peak of MgCl2 (181.33 °C) is shifted in composites MX/Mg 15 % (159.63 °C) and MX/Mg 10 %, (141.67 °C) toward lower dehydration temperature. The cyclicability study demonstrated that in the 10 consecutive rehydration cycles, MgCl2 shows 45 % decrease in the enthalpy, while Mg/MX 10 % and Mg/MX 15 % composites record 4 % and 10 % decrease, respectively. Water uptake kinetics highlighted that at 85 % RH, the highest water sorption was recorded for Mg/MX 15 % where it absorbs 2.21 g/g mass. The energy storage density result reveals that the maximum loading rate of MgCl2·6H2O reaches 97.6 wt% for Mg/MX 15 % showed the highest enthalpy 2227 J/g at 85 % RH. Therefore, all the results indicate that MXene-based salt composites play an important role in thermochemical heat storage application, leading to a potential candidate for long-term heat storage.

GReek Anaesthesiologists's Burnout EPidemic within the COVID-19 pandemic (GRABEP study); a multicenter study on burn out prevalence among Greek anesthesiologists and association with personality traits.

COVID-19 pandemic resulted in an unprecedented crisis with extreme distress for the frontline physicians and increased risk of developing burnout. Burnout has a negative impact on patients and physicians, posing a substantial risk in patient safety, quality of care and physicians' overall wellbeing. We evaluated burnout prevalence and possible predisposing factors among anaesthesiologists in the COVID-19 referral university/tertiary hospitals in Greece. In this multicenter, cross-sectional study we have included anaesthesiologists, involved in the care of patients with COVID-19, during the fourth peak of the pandemic (11/2021), in the 7 referral hospitals in Greece. The validated Maslach Burnout Inventory (MBI) and Eysenck Personality Questionnaire (EPQ) were used. The response rate was 98% (116/118). More than half of the respondents were females (67.83%, median age 46 years). The overall Cronbach's alpha for MBI and EPQ was 0.894 and 0.877, respectively. The majority (67.24%) of anaesthesiologists were assessed as "high risk for burnout" and 21.55% were diagnosed with burnout syndrome. Almost half participants experienced high levels of all three dimensions of burnout; high emotional exhaustion (46.09%), high depersonalization (49.57%) and high levels of low personal accomplishment (43.49%). Multivariate logistic analysis revealed that neuroticism was an independent factor predicting "high risk for burnout" as well as burnout syndrome, whereas the "Lie scale" of EPQ exhibited a protective effect against burnout. Burnout prevalence in Greek anaesthesiologists working in COVID-19 referral hospitals during the fourth peak of the pandemic was high. Neuroticism was predictive of both "high risk for burnout" and "burnout syndrome".

Socio-demographical Profile of 7285 SARS-Cov-2 Positive Early Cases; Comparison with National Four Epidemic Waves.

Background: Objectives were to investigate aspects of the COVID-19 epidemics via testing the individuals who were referred to Aramesh Medical Laboratory in Tehran and to integrate the molecular results with epidemiological data since the beginning of the epidemic. Methods: In this cross-sectional Study 77528 outpatients were referred to Aramesh Medical laboratory by physicians for the diagnosis of SARS-CoV-2 infection between March 2019 and May 2021. Viral acid nucleic extracted from nasal and throat specimens and subsequently amplified using Reverse Transcriptase Real-Time PCR. Laboratory data including Ct values compared with epidemic peaks of COVID-19 countrywide. Statistical Analysis was done by SPSS 21 Software. Results: 14312 (18.46%) tested positive.36.5% of the positive cases were in the 30 to 39 years old age group. The positive result rate was significantly different based on months, ranging from 6% to 28%, compatible with four recognized epidemic peaks encompassing the end of March through the first week of April (first epidemic peak), from June to July 2020 (second epidemic peak), October until mid of November 2020 (third epidemic wave) followed by the end of April to May 2021 (until the end period of study, in the middle of 4th peak). In 37.8% of cases, the Ct value was between 21 and 28. Two separate trends were seen for Ct ≤ 25 and Ct ≤ 20 for the first and fourth epidemic peaks, respectively. There was an association between the number of total monthly positive results and total deaths in the country, especially with the second to third peaks (in the course of summer 2020) and fourth epidemic peak. Conclusion: It might be useful to consider laboratory admission rates as an indicator for changes in the epidemic level in the country to continue the SARS-CoV-2 surveillance in accordance with public decision-makers.

Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) antigen detection in the Emergency Department: data from a pediatric cohort during the fourth COVID-19 wave in Italy

BackgroundSevere Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) pandemic has been challenging health care systems and made it necessary to use rapid and cost-effective testing methods, particularly in Emergency Department (ED) settings. Rapid Antigen Diagnostic Tests (RADTs) are a valid alternative to the gold standard RT-PCR, even in pediatric populations. This retrospective observational study has been conducted on a pediatric cohort afferent to the ED of the San Giovanni di Dio and Ruggi d’Aragona University Hospital in Salerno, tested at Point of Care with RADT Panbio® (Abbott), from September 1st, 2021 to February 28th, 2022, analyzing the positivity rate and clinical features of the cohort, also in reference to the rise of positive cases observed in the aforementioned period, and to the introduction in Italy of SARS-CoV-2 vaccination for children and teens on December 16th, 2021.MethodsData regarding access to the pediatric ED were extracted from the hospital’s electronic database system. Parallel to this, we conducted a narrative literature search using PubMed database focusing on the use of RADT in pediatric ED and compared our data with the national pandemic trend.ResultsDuring the observation period, 1890 patients were tested for the presence of SARS-CoV-2 with RADT and the 2.7% of children resulted positive, with a peak in January 2022. The main symptoms in positive patients were: fever (n = 34; 66.7%), cough (n = 11; 21.5%), headache (n = 4; 7.8%), chest pain (n = 2; 3.9%) and abdominal pain (n = 1; 2%). Patients were divided into three different age groups (A, B, C) basing on the different access timing to vaccination; no statistically significant difference was detected in the distribution of positivity in these three groups (p > 0.05). Number of positive children in group A was greater in the post-vaccine group. Our data are concordant with the national trend of the pandemic showing a fourth wave peak in January 2022.ConclusionThe use of RADT as a first point-of-care screening may be helpful, time-saving and cost-sparing. Our study shows that, during the observation period, most children admitted to the ED for fever, actually tested positive for SARS-CoV-2 with a statistically greater difference than negative children. Instead, number of patients admitted for cough was statistically higher among negative than positive ones, probably due to the circulation of other respiratory viruses in children.

Disease Waves of SARS-CoV-2 in Iran Closely Mirror Global Pandemic Trends

Background: Complete SARS-CoV-2 genome sequencing in the early phase of the outbreak in Iran showed two independent viral entries. Subsequently, as part of a genome surveillance project, we aimed to characterize the genetic diversity of SARS-CoV-2 in Iran over one year after emerging. Methods: We provided 319 SARS-CoV-2 whole-genome sequences used to monitor circulating lineages in March 2020-May 2021 time interval. Results: The temporal dynamics of major SARS-CoV-2 clades/lineages circulating in Iran is comparable to the global perspective and represent the 19A clade (B.4) dominating the first disease wave, followed by 20A (B.1.36), 20B (B.1.1.413), 20I (B.1.1.7), leading the second, third and fourth waves, respectively. We observed a mixture of circulating B.1.36, B.1.1.413, B.1.1.7 lineages in winter 2021, paralleled in a fading manner for B.1.36/B.1.1.413 and a growing rise for B.1.1.7, prompting the fourth outbreak. Entry of the Delta variant, leading to the fifth disease wave in summer 2021, was detected in April 2021. This study highlights three lineages as hallmarks of the SARS-CoV-2 outbreak in Iran; B4, dominating early periods of the epidemic, B.1.1.413 (B.1.1 with the combination of [D138Y-S477N-D614G] spike mutations) as a characterizing lineage in Iran, and the co-occurrence of [I100T-L699I] spike mutations in half of B.1.1.7 sequences mediating the fourth peak. It also designates the renowned combination of G and GR clades’ mutations as the top recurrent mutations. Conclusion: In brief, we provided a real-time and comprehensive picture of the SARS-CoV-2 genetic diversity in Iran and shed light on the SARS-CoV-2 transmission and circulation on the regional scale.

Mental Health, Burnout, and Job Stressors Among Healthcare Workers During the COVID-19 Pandemic in Iran: A Cross-Sectional Survey.

IntroductionThe COVID-19 pandemic has caused increasing levels of mental health problems such as anxiety and depression among doctors, nurses and other healthcare workers in hospitals or health centers. The main objective of this study was to assess the mental health, job stressors, and burnout among healthcare workers in Iran.Materials and MethodsA cross-sectional study was performed in the primary healthcare centers and hospitals affiliated with six of the medical universities in Iran. The selection of participants was done using multi-center convenient sampling. The Patient Health Questionnaire-9, Generalized Anxiety Disorder-7, and Copenhagen Burnout Inventory were used for gathering data through an online platform. Data related to job stressors were obtained using a validated checklist. Data analysis was performed using Chi-square and multiple regression tests and the phi coefficient.ResultsThe results of our study showed that 53% of the healthcare workers of the hospitals and primary healthcare centers enrolled in our study either had generalized anxiety disorder or major depressive disorder or both disorders. Moderate and high levels of burnout were seen among 48.9% of the study participants. The prevalence of mental disorders and burnout were significantly higher among the female healthcare workers compared to the male (p = 0.0001) and a higher rate of mental disorder and burnout was also seen among healthcare workers of hospitals compared to those working in primary healthcare centers (p = 0.024). “Worry about children and old members of family,” “family worries for my health condition” and “lack of specific effective treatment for COVID-19” were found to be predictive of mental disorder and burnout. The most prevalent job stressor among the total sample was “low payment or income during the COVID-19 period”.ConclusionThe results of our study revealed high psychological distress and burnout among healthcare workers of the hospitals during the fourth peak of the COVID-19 pandemic in Iran. This study highlights the need for health officials to pay attention to the job stressors of healthcare workers and obliges them to perform effective interventions to address their needs and concerns.

High-ferrite Portland cement with slag: Hydration, microstructure, and resistance to sulfate attack at elevated temperature

Among the four mineral components in cement, C4AF has been demonstrated to have satisfactory corrosion resistance to sulfate attack. Here, high-ferrite Portland cement (HFPC) is used to prepare high corrosion-resistance cement-based materials. The hydration mechanisms and pore structures of HFPC pastes containing different slag dosages are studied at 20 °C, 40 °C, and 60 °C. The results indicate that the elevated temperature greatly stimulates the slag activity and significantly promotes the hydration of HFPC/slag blends. As the temperature increases, the heat curve of the cement pastes with high content slag shows a third or fourth exothermic peak. The hydration of pastes with more than 40% slag is controlled by the nucleation of hydrates in the acceleration stage and by the diffusion of ions in the deceleration stage above 40 °C. In addition, the HFPC pastes show excellent mechanical properties in a high-temperature environment. The HFPC pastes exhibit better sulfate attack resistance performance compared with pure ordinary Portland cement (OPC) ones. Therefore, the excellent performance of HFPC-based materials can be applied in the construction of concrete in mass under the environment of the South Sea in China, to solve the problems of high environmental temperature, large temperature differences, and sulfate attack.

Development and certification of a pharmacopoeial reference standard for primary structure identification of purified recombinant interferon beta-1b by peptide mapping

Medicines based on recombinant human interferons (rhIFNs) beta-1a and beta-1b are used as first-line treatment of multiple sclerosis. Meanwhile, rhIFN beta-1a and beta-1b have structural differences associated with the eukaryotic or prokaryotic expression systems, respectively. Pharmacopoeias require identification of the primary structure of recombinant proteins by peptide mapping, which involves the use of reference material. Currently, there is no international reference standard available for rhIFN beta-1b structural identification. The aim of the study was development and certification of a pharmacopoeial reference standard for identification of the amino acid sequence of purified rhIFN beta-1b by peptide mapping. Materials and methods: rhIFN beta-1b produced by GENERIUM and endoproteinase Glu-C from Staphylococcus aureus V8 were used in the study. The peptide mapping was performed using reverse-phase high-performance liquid chromatography (RP HPLC) and high-resolution mass spectrometry. Statistical evaluation of the results included calculation of the arithmetic mean, standard deviation, and coefficient of variation. Results: the authors developed and certified a Russian Pharmacopoeia reference standard for structural identification of rhIFN beta-1b (PhRS 3.2.00447). The certified characteristic is the range of retention times of characteristic peaks: the absolute retention time was 42.0–43.2 for the third (reference) peak, the relative retention time was 0.61–0.66 for the first peak, 0.68–0.73 for the second peak, 1.04–1.06 for the fourth peak, 1.14–1.15 for the fifth peak, 1.22–1.24 for the sixth peak, and 1.29–1.30 for the seventh peak. Conclusions: the authors developed requirements for the rhIFN beta-1b pharmacopoeial reference standard. The material chosen as the candidate reference standard was an intermediate rhIFN beta-1b product sampled before addition of human serum albumin. The quality control was carried out in accordance with the developed specification. The authors analysed the amino acid sequence of the molecule, confirmed the presence of the disulfi e bond, and obtained the certifi d characteristic of the reference standard. Comparative analysis of the peptide maps of the certified rhIFN beta-1b pharmacopoeial reference standard and the rhIFN beta-1a reference standard revealed differences between the maps, and, therefore, confirmed the relevance of the developed reference standard.

Quad-band terahertz metamaterial absorber using three parallel gold strips surrounded by two identical gold ring arcs

Quad-band terahertz metamaterial absorber with near-perfect absorption is given in this paper. It is designed by a patterned Au layer and a continuous Au film separated by an insulating dielectric layer, of which the patterned Au layer is consisted of three parallel Au strips (a longer and two shorter) surrounded by two Au ring arcs of the same size. Four separated terahertz absorption peaks with narrow bandwidths and large absorptance are realized. The first three absorption peaks are due to the fundamental modes of the Au strips and the Au ring arcs, while the fourth absorption peak is ascribed to the excitation of three-order resonance in the Au ring arcs. The field distributions of the four absorption peaks are presented to verify their physical mechanisms. The influence of geometrical dimensions of the proposed configuration on the performance of the quad-band light absorption is discussed. Moreover, considering the potential sensing applications, the sensing performance of the proposed absorption device is also explored. The suggested scheme could provide considerable application prospects in selective thermal radiation, spectral imaging, sensing, detecting, electromagnetic stealth, etc.

Treatment Technologies of Human Coronavirus: Myth or Realism

Since the outbreak of corona pandemic, in the absence of cure so far, many hit and trial techniques have been tried out for treating the disease COVID-19. In current scenario, numerous countries in the world are facing the fourth peak of the pandemic as Omicron, which is the new mutation of the Delta as the most dominant variant. As various medicine companies have declared different vaccines but none of them are claiming the hundred percent protection against this severe infection. In pursuit of the various available treatments, even rumour-mongering is thriving thick and fast. Many myths about treatment techniques were speeded through social media and people started to adopt them due to fear of psychosis and ignorance. The reported study focuses on the status of the pandemic world over so far, cause of COVID-19 including symptoms and testing mechanism, the insight on vulnerable section and the suggested protocol for them. It also highlights about the myths prevalent in the society and the fact check of the various treatment techniques adopted. This work also depicts the developmental status of COVID-19 vaccine all over the world and presents a comprehensive study of development of treatment technologies in order to pave way for researchers to work further in the quest of development of universal medicine(s) and vaccine(s) for treating the newly muted virus i.e., Omicron so that world becomes free of the menace or can commence normal life.

Introductory Models of COVID-19 in the United States

ABSTRACT Students develop and test simple kinetic models of the spread of coronavirus disease 2019 (COVID-19) caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus. Microsoft Excel is used as the modeling platform because it is nonthreatening to students and it is widely available. Students develop finite difference models and implement them in the cells of preformatted spreadsheets following a guided inquiry pedagogy that introduces new model parameters in a scaffolded step-by-step manner. That approach allows students to investigate the implications of new model parameters in a systematic way. Students fit the resulting models to reported cases per day data for the United States using least squares techniques with Excel's Solver. Using their own spreadsheets, students discover for themselves that the initial exponential growth of COVID-19 can be explained by a simplified unlimited growth model and by the susceptible-infected-recovered (SIR) model. They also discover that the effects of social distancing can be modeled using a Gaussian transition function for the infection rate coefficient and that the summer surge was caused by prematurely relaxing social distancing and then reimposing stricter social distancing. Students then model the effect of vaccinations and validate the resulting susceptible-infected-recovered-vaccinated (SIRV) model by showing that it successfully predicts the reported cases per day data from Thanksgiving through the holiday period up to 14 February 2021. The same SIRV model is then extended and successfully fits the fourth peak up to 1 June 2021, caused by further relaxation of social distancing measures. Finally, students extend the model up to the present day (27 August 2021) and successfully account for the appearance of the delta variant of the SARS-CoV-2 virus. The fitted model also predicts that the delta variant peak will be comparatively short, and the cases per day data should begin to fall off in early September 2021, counter to current expectations. This case study makes an excellent capstone experience for students interested in scientific modeling.

Modeling the Dynamics and Forecasting the fourth Peak of COVID-19 in Iran Using PSO Algorithm

Background and aims: Iran had passed the third peak of COVID-19 pandemic, and was probably witnessing the fourth peak at the time of this study. This study aimed to model the spread of COVID-19 in Iran in order to predict the short-term future trend of COVID-19 from April 23, 2021 to May 7, 2021. Methods: In this study, a modified SEIR epidemic spread model was proposed and the data on the number of cases reported by Iranian government from February 20, 2020 to April 23, 2021 were used to fit the proposed model to the reported data using particle swarm optimization (PSO) algorithm. Then the short-term future trend of COVID-19 cases were predicted by using the estimated parameters. Results: The results indicated that the effective reproduction number increased in Nowruz (i.e., Persian New Year, 1400) and it was estimated to be 1.28 in the given period. According to the results from the short-term prediction of COVID-19 cases, the number of active confirmed cases in the fourth peak was estimated to be 516411 cases on May 2, 2021. Conclusion: Following the results from our short-term prediction, implementing strict social distancing policies was found absolutely necessary for relieving the Iran’s health care system of the tremendous burden of COVID-19.