J, Volume 6, Issue 1 (March 2023) – 15 articles

Rapid antigen testing (RAT) is a cost-effective and time-efficient method of identifying severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and therefore a critical part of infection control strategies. There is no published evidence evaluating the use of RAT during the Omicron wave of the COVID-19 pandemic for asymptomatic patients or its performance between waves. All patients presenting to an Emergency Department over a two-week period without COVID-19 symptoms were screened for SARS-CoV-2 using both the Abbott Panbio RAT as well as the gold standard reverse transcriptase real-time polymerase chain reaction (PCR). The Abbott Panbio RAT sensitivity was 13% (95% CI 0.028, 0.336) for asymptomatic patients. The use of this test in asymptomatic patients during the Omicron wave had a statistically significant reduction in sensitivity compared with two reports of the same test in previous waves (13% vs. 86%, p < 0.0001; 13% vs. 83%, p < 0.0001). As SARS-CoV-2 continues to mutate, the sensitivity of RATs are altered and needs to be continually re-evaluated for each variant of concern if they are to be used as part of an infection control strategy. Full article

When finger joints become immobile due to an accident during sports or a widespread disease such as rheumatoid arthritis, customised finger joint implants are to be created. In an automated process chain, implants will be produced from ceramic or metallic materials. Artificial intelligence-supported software is used to calculate three-dimensional models of the finger bones from two-dimensional X-ray images. Then, the individual implant design is derived from the finger model and 3D printed. The 3D printing process and the structures used are evaluated via model tests and the final implant design via a reliability calculation in a way to ensure that this is also possible via an AI process in the future. Using additive manufacturing with silicon nitride-based ceramics, model specimens and implants are produced via the lithography-based ceramic vat photopolymerisation process with full geometry or elements of triple periodic minimal surfaces structure. The model specimens are tested experimentally, and the loads are matched with a characteristic strength assuming a Weibull distribution of defects in the volume to generate and match failure probabilities. Calculated fracture forces of the silicon nitride-based ceramic structure was validated by comparison of simulation and tests, and the calculation can be used as a quality index for training of artificial intelligence in the future. The proposed method for individualized finger implant design and manufacturing may allow for correction of potential malpositions of the fingers in the future. Full article

The acute toxicity of the detergent Nittol^® 0.8, 1.0, 1.2, 1.4, 1.6, and 0.0 mg NTL/L of clean water on Heterobrunchus bidorsalis, 5.5 ± 0.3 g, 6.4 ± 0.5 cm were investigated, using semi-static bioassay, for 96 h in 50 L capacity plastic test bowls. The fingerlings of the same brood stock and age were collected from Onose Farms Limited, Ughelli, Delta State to the University Research Laboratory, Enugu Lat. 7.4 N; 8°7′5 and long 6°8′ E. 7°6′ W. The test fish were acclimatized for 14 days, and fed at 3% body weight once daily, on a 40% CP commercial diet. Feeding was suspended 24 h before and during the range finding and acute tests. The whole set-up was replicated three times, and no death was recorded during the acclimatization period and in the control. A total of 180 fingerlings were used, and 10 fingerlings were assigned to each replicate. The test set-up was monitored daily for water quality parameters, opercular ventilation, tail fin beat frequency, and mortality. Dose and time-dependent behavioural patterns exhibited by the test fish, during the exposure periods include rapid swimming, air gulping, loss of balance, and a period of convulsion before death. Significant elevation in pH and temperature, reduction of DO compared to the control (p < 0.05) in the water quality, and dose-dependent early elevation of the tail and fin movements declined towards the end of the experiment. The 96 h LC₅₀ was determined to be 1.41 mg/L, indicating that the detergent NTL is toxic to the test fish. The haematological parameters were significantly (p < 0.05) reduced in the treated ranges of RBC 5.20 ± 0.07–8.00 ± 0.02 × 10⁶ mm³, HB 7.53 ± 0.50–10.72 ± 0.14 g/dl, PCV 13.20 ± 0.8.50–18.00 ± 0.43 % below their elevated respective controls of 10.50 ± 0.01 × 10 ⁶ mm³, 11.00 ± 0.01 g/dl, and 23.48 ± 0.2.6 %. The white blood cells (WBC) recorded a significant (p < 0.05) increase in ranges of 23.72 ± 0.14–51.80 ± 1.9 × 10³ mm³ above the control value of 11.00 ± 0.01 × 10³ mm³ Therefore, values greater than the safe amount of 0.014 mg/L should not be allowed in the receiving culture waters for Heterobrunchus bidorsalis fingerlings. Full article

Background: The Coronavirus Disease 2019 (COVID-19) is a global pandemic that has killed over 1.5 million people worldwide. A constellation of multisystem involvement with SARS-CoV-2 has been reported. COVID-19 has been shown to affect the human nervous system, however, both the extent and severity of involvement have yet to be fully elucidated. In this manuscript, we aimed to better understand the effect of COVID-19 on neuro-respiratory status by studying COVID-19 patients who presented with central apnea. Methodology: We analyzed patient characteristics, clinical outcomes, laboratory results, and imaging results of three patients with symptomatic, PCR-proven COVID-19 and episodes of central apnea. Results: Of the three patients included in this study, two patients developed new central apnea, and one patient developed an exacerbation of underlying central apnea despite COVID-19 treatments with systemic steroids and remdesivir. All occurred, on average, 15 days after the onset of COVID-19 symptoms. At 1-year follow-up, all patients experienced complete resolution of apneic breathing. Conclusions: Physicians should be vigilant for the presentation of COVID-19 with central apnea. Central apnea may be a complication in patients with severe COVID-19 infection. More research is warranted to further understand this association. Full article

Recent attempts at searching for new materials have revealed a large class of materials that show topological behaviors with unusual physical properties and potential applications leading to enthralling discoveries both theoretically and experimentally. We computationally predict new three-dimensional topological compounds of space group 139(I/4mmm). After conducting a full volume optimization process by allowing the rearrangement of atomic positions and lattice parameters, the first-principles calculation with a generalized gradient approximation is utilized to identify multiple Dirac-type crossings around X and P symmetric points near Fermi energy. Importantly, the band inversion at point P is recognized. Further, we investigate the compound for topological crystalline insulating behavior by conducting surface state calculation and by investigating gapping behavior by increasing lattice parameters. Additionally, we perform formation energy, elastic properties, and phonon modes calculations to verify the structural, mechanical, and dynamical stability of the compounds. Therefore, we suggest compounds for further investigation and experimental realization. Full article

Solving nonlinear oscillations is a challenging task due to the mathematical complexity of the related differential equations. In many cases, determining the oscillation’s period requires the solution of complicated integrals using numerical methods. To avoid the complexity, there are many empirical equations in the literature that can be used instead of rigorous mathematical analysis to provide an acceptable approximation. In this paper, a recently developed method, He’s formulation, is applied to find the period in many different cases of nonlinear oscillators. The cases are those of the Duffing equation, the Helmholtz nonlinear oscillator, the simple pendulum and the case of a vertical oscillation under the influence of a nonlinear elastic force. The results of the method are accurate; thus, He’s formulation is a strong tool for solving nonlinear oscillations. Full article

Local communities in Mzimba District, Malawi, have limited access to healthcare services and often rely on traditional medical practice and medicinal plants (MPs) for most of their medical care. However, phytomedicines’ use has not been well documented. This study aimed to identify and document medicinal plants and the associated ethnobotanical knowledge. Ethnobotanical data were collected in seven localities (19 villages) in the T/A Mbelwa, Mzimba, from May to June 2021. Forty traditional healers, herbalists, and farmers selected purposively and by snowball sampling were interviewed through semi-structured interviews, field observations, group discussions, and guided field walks. Quantitative indices, viz. relative frequency of citation (RFC), use value (UV), relative importance (RI) values, informant consensus factors (ICFs), and fidelity levels (FLs), were used to analyze the data. Eighty MPs belonging to 43 families and 77 genera were recorded. The Leguminosae family showed the highest number of species (16), followed by Solanaceae, Rubiaceae, and Phyllanthaceae. Trees (35 species) and roots (62%) accounted for the most significant habit and part, respectively. Washing (29%) was the most common preparation method. The most cited plant was Zanthoxylum chalybeum (RFC = 0.80, UV = 0.28, RI = 1.66), followed by Cassia abbreviata (RFC = 0.68, UV = 0.35, RI = 1.50). Respiratory disorders showed the highest ICF (0.53), followed by general and unspecified disorders (0.31). Z. chalybeum, C. abbreviata, and Oldfieldia dactylophylla showed maximum FLs (100%) for treating malaria and dysentery. Phytochemical, bioassay, toxicity, and conservation studies are needed to assess medicinal plants’ safety, efficacy, and quality as steps toward discovering new promising therapeutic leads without neglecting conservation programs for their sustainable utilization. Full article

The negative chronotropic effects of eight Vaughan Williams Class I antiarrhythmic drugs were examined in guinea pig right atrial tissue preparations. The drugs decreased the spontaneous beating rate at concentrations overlapping with their therapeutic blood levels. Cibenzoline, aprindine, flecainide, and propafenone showed stronger effects; 10 µM of each drug decreased the beating rate to about 75% of initial values. Disopyramide, mexiletine, pilsicainide, and ranolazine showed weaker effects; 10 µM of each drug decreased the beating rate to about 90% of initial values. The potency of drugs correlated with the reported IC₅₀ values to block the L-type Ca²⁺ channel current rather than the Na⁺ and K⁺ channel currents. The reported IC₅₀ values for the blockade of the hyperpolarization-activated inward current (If) and the Na⁺-Ca²⁺ exchanger current were much higher than those for the blockade of the L-type Ca²⁺ channel current. These results indicate that the negative chronotropic effects of Class I antiarrhythmic drugs can be largely explained by their blockade of the L-type Ca²⁺ channel. Full article

Pulchellin is a plant biotoxin categorized as a type 2 ribosome-inactivating protein (RIPs) which potentially kills cells at very low concentrations. Biotoxins serve as targeting immunotoxins (IT), consisting of antibodies conjugated to toxins. ITs have two independent protein components, a human antibody and a toxin with a bacterial or plant source; therefore, they pose unique setbacks in immunogenicity. To overcome this issue, the engineering of epitopes is one of the beneficial methods to elicit an immunological response. Here, we predicted the tertiary structure of the pulchellin A-chain (PAC) using five common powerful servers and adopted the best model after refining. Then, predicted structure using four distinct computational approaches identified conformational B-cell epitopes. This approach identified some amino acids as a potential for lowering immunogenicity by point mutation. All mutations were then applied to generate a model of pulchellin containing all mutations (so-called PAM). Mutants’ immunogenicity was assessed and compared to the wild type as well as other mutant characteristics, including stability and compactness, were computationally examined in addition to immunogenicity. The findings revealed a reduction in immunogenicity in all mutants and significantly in N146V and R149A. Furthermore, all mutants demonstrated remarkable stability and validity in Molecular Dynamic (MD) simulations. During docking and simulations, the most homologous toxin to pulchellin, Abrin-A was applied as a control. In addition, the toxin candidate containing all mutations (PAM) disclosed a high level of stability, making it a potential model for experimental deployment. In conclusion, by eliminating B-cell epitopes, our computational approach provides a potential less immunogenic IT based on PAC. Full article

The two-parameter logistic (2PL) item response model is likely the most frequently applied item response model for analyzing dichotomous data. Linking errors quantify the variability in means or standard deviations due to the choice of items. Previous research presented analytical work for linking errors in the one-parameter logistic model. In this article, we present linking errors for the 2PL model using the general theory of M-estimation. Linking errors are derived in the case of log-mean-mean linking for linking two groups. The performance of the newly proposed formulas is evaluated in a simulation study. Furthermore, the linking error estimation in the 2PL model is also treated in more complex settings, such as chain linking, trend estimation, fixed item parameter calibration, and concurrent calibration. Full article

A lot of libraries for neural networks are written for Turing-complete programming languages such as Python, C++, PHP, and Java. However, at the moment, there are no suitable libraries implemented for a p-complete logical programming language L. This paper investigates the issues of polynomial-computable representation neural networks for this language, where the basic elements are hereditarily finite list elements, and programs are defined using special terms and formulas of mathematical logic. Such a representation has been shown to exist for multilayer feedforward fully connected neural networks with sigmoidal activation functions. To prove this fact, special p-iterative terms are constructed that simulate the operation of a neural network. This result plays an important role in the application of the p-complete logical programming language L to artificial intelligence algorithms. Full article

Foot-related problems are prevalent across the globe, and this issue is aggravated by the presence of diabetes mellitus. Diabetic-foot-related issues include extreme foot pain, plantar corns, and diabetic foot ulcers. To assess these conditions, accurate characterization of plantar pressure is required. In this work, an in-shoe, low-cost, and multi-material pressure measuring insole, based on a piezoresistive material, was developed. The device has a high number of sensors, and was tested on 25 healthy volunteers and 25 patients with different degrees of diabetes. The working range of the device was observed to be 5 kPa to 900 kPa, with an average hysteresis error of 3.25%. Plantar pressure was found to increase from healthy to diabetic volunteers, in terms of both standing and walking. In the case of the diabetic group, the-high pressure contact area was found to strongly and positively correlate (R² = 0.78) with the peak plantar pressure. During the heel strike phase, the diabetic volunteers showed high plantar pressure on the medial heel region. In regard to the toe-off phase, the central forefoot was found to be a prevalent site for high plantar pressure across the diabetic volunteers. The developed device is expected not only to assist in the prediction of diabetic ulceration or re-ulceration, but also to provide strategies and suggestions for foot pressure alleviation and pain mitigation. Full article

The current deployment of 5G NR in the frequency band 4800–4990 MHz in multiple countries near the coastlines indicated that there might be a potential risk of harmful interference impacting aeronautical and maritime systems located in international airspace and international waters. This raised numerous concerns about whether 5G NR system rollouts in that band need to be restricted by the power flux density limits created at the border of the territorial waters, which equals 12 nautical miles from the coastline. This work contains a case study based on the example of the Pacific region, where a simulation of aggregate interference from 5G NR base stations and user equipment deployed in the cities near the coastline using Monte Carlo analysis was conducted. The results of the study show that no harmful interference to the aeronautical and maritime services operating in international airspace and waters is expected even when the aircraft or vessels are located at the border of the territorial airspace and waters from the coastline. Therefore, no restriction to the 5G NR deployment in the coastline regions in the frequency band 4800–4990 MHz is required. Full article

Groundwater (GW) flooding mechanisms differ from river flooding, both spatially and temporally, and preventative methods against groundwater flooding must take this into account. Although groundwater flooding caused by a rise of river water seldom occurs, it can occasionally become severe and last for a long time if the river is significantly flooded. In the southwest portion of the research domain, Friedrichshafen, Germany, with a few urban communities, the level of the groundwater table was discovered to be roughly 1 m below the surface. In the study region, it is typical for the bottom level of the foundation of a single-story building to extend up to a depth of about 1.5 m. Therefore, flood mitigation methods are taken into account for the southwest portion of the study region. In this study, FEFLOW is used to explore the preventative methods for groundwater flooding caused by river water increase in urban settings, the spread of contamination, and the strategizing of effective mitigation solutions for flooding. The installation of a pumping well, drainage, and a barrier in the affected area are three different flood control strategies that are taken into consideration for the study area. Pumping well installation, reducing up to 1.5 m of hydraulic head, was found to be the most effective flood control measure locally in a small region. By contrast, removing groundwater by building drainage and barriers was shown to be ineffective for lowering the groundwater table over an extended region, and was significantly more expensive than the installation of wells. Additionally, when river flooding is taken into account, compared to the default scenario where no intake of water from the river is included along the western border of the study area, it was discovered that the spread of pollution (nitrate concentration) is significantly greater. Full article