Search

BACKGROUND: Since its first outbreak, coronavirus disease 2019 (COVID-19) has led to a great deal of published literature highlighting the short-term determinants of morbidity and mortality. Recently, several studies have reported radiological and functional sequelae from 3 months to 1 year among hospitalized COVID-19 survivors; however, long-term (more than 1 year) respiratory consequences in this population remain to be evaluated. OBJECTIVE: To assess the long-term radiological and pulmonary function outcomes of patients with COVID-19 2 years after resolution of the initial infection. METHODS: Hospitalized COVID-19 patients with moderate to severe disease who survived acute illness were included in this prospective and partially retrospective study. Clinical assessment, laboratory tests, high-resolution computed tomography scans, and pulmonary function tests (PFTs) were performed at baseline, followed by radiological and lung function assessments at 6 and 24 months. RESULTS: Among 106 enrolled participants (mean age 62 ± 13.5 years; males: 61), 44 (41.5%) and 27 (25.4%) underwent radiological assessment at 6 and 24 months, respectively. Overall, 22.6% (24) of patients had residual radiological abnormalities. Overt fibrosis was observed in 12.2% of patients. Computed tomography disease severity and extent diminished significantly at 6 (13 ± 6, P < 0.001) and 24 months (11 ± 6, P < 0.001) from baseline. PFTs were performed in 65 (61.3%), 22 (20.7%), and 34 (32%) patients at baseline, 6 and 24 months, respectively. Impaired diffusion capacity (median diffusion capacity for carbon monoxide: 60%, interquartile range [IQR]: 51–80), restrictive lung defect (mean total lung capacity: 73.4% ± 18% predicted), and reduced exercise tolerance (median 6-min walk distance: 360 m, IQR: 210–400) were the predominant features at baseline. With the exception of exercise tolerance, a statistically significant improvement was observed in lung function parameters at the extended follow-up (2 years). CONCLUSIONS: Hospitalized COVID-19 survivors are at increased risk of developing long-term pulmonary complications, including lung fibrosis. A protocol-based approach to the management of post-COVID-19 patients is mandatory to improve future outcomes.

The phenomenon of fine particle migration through the voids of the granule skeleton under the seepage force is called suffusion. Relative density, original fine particle content, and gap ratio are thought to play vital roles in the suffusion process. This paper investigates the effect of geometrical characteristics (i.e., original fine particle content, gap ratio, and relative density) on soil structure and mechanical performance (i.e., small strain shear modulus) using the bender element method technique. The small strain shear modulus (G0) is used as a mechanical parameter to evaluate the shear stress transmission of the soil structure along with the erosion process. The comparison between erosion percentage and vertical strain change suggests the alteration in soil fabric after soil erosion. The G0 monitoring results show that packings with a higher original fine particle content have a lower G0 value, whereas the gap ratio and relative density present a positive relationship with G0.

Bitumen has been used in different forms and with various properties in pavement as a binder material. Meanwhile, the properties of soil-rubber mixtures (SRM) have been extensively examined for applications in geotechnical and highway engineering. These applications range from serving as a lightweight fill material, subgrade layers in pavement, and foundation materials for geotechnical seismic isolation (GSI). However, a research gap exists in understanding the effect of the interaction between bitumen and rubber granules on their mechanical properties under a range of confining pressures. In this paper, a series of unconfined compressive strength (UCS) and monotonic triaxial tests were conducted. The results show that a bitumen content as low as 3% of the total mass can significantly increase the shear strength and cohesion of SRM and reduce the deformability. Moreover, the increase in the elastic modulus due to a 3–5% bitumen content is notably less than the reduction obtained from 25% to 45% rubber replacement, which is favourable for GSI applications. The shear strength and elastic modulus in gravel-based mixtures were found to be more sensitive to changes in rubber and bitumen content compared to sand-based mixtures. Conversely, the effect of confining pressure was more pronounced in sandy soil than in gravelly soil.

Abstract Solar energy has emerged as a pivotal player in the transition towards sustainable and renewable power sources. However, the efficiency and longevity of solar cells, the cornerstone of harnessing this abundant energy source, are intrinsically linked to their operating temperatures. This comprehensive review delves into the intricate relationship between thermal effects and solar cell performance, elucidating the critical role that temperature plays in the overall efficacy of photovoltaic systems. The primary objective of this review is to provide a comprehensive examination of how temperature influences solar cells, with a focus on its impact on efficiency, voltage, current output, and overall stability. By synthesizing existing knowledge and exploring recent advances in the field, we aim to elucidate the underlying mechanisms of thermal effects and offer insights into mitigating their adverse consequences. Our review encompasses a thorough discussion of the fundamentals of solar cells, including their operation and various types, before delving into the intricacies of thermal effects. We present an overview of experimental techniques for thermal analysis, factors influencing temperature variations, and strategies to alleviate thermal stresses. Additionally, we offer real-world case studies and discuss future trends and research directions, providing a comprehensive roadmap for advancing solar cell technology. In an era where the harnessing of solar energy has become increasingly vital, understanding and addressing thermal effects are imperative to maximize the efficiency and longevity of solar cells. This review article serves as a valuable resource for researchers, engineers, and policymakers by shedding light on the significance of thermal effects on solar cell performance and guiding the pursuit of innovative solutions in the quest for more efficient and sustainable photovoltaic systems.

Abstract In this study, we synthesized a novel corrosion inhibitor derived from thiophene and conducted a comprehensive evaluation of its inhibitory properties through both experimental and theoretical approaches. Our investigation encompassed experimental assessments employing Mass loss tests and electrochemical techniques. Additionally, we performed computational studies to delve into the electronic structure and bonding characteristics of the inhibitor, aiming to elucidate its inhibitory mechanism. Our findings revealed that the synthesized inhibitor displayed remarkable inhibitory efficiency, demonstrating its effectiveness in preventing the corrosion of mild steel. Specifically, the thiophene derivative exhibited an impressive inhibitory efficiency of 92.8%, underscoring its potential as a robust corrosion inhibitor for mild steel. Furthermore, this study delved into optimizing the conditions for employing the thiophene derivative as a corrosion inhibitor. Our investigation revealed that the most effective inhibition was achieved at a concentration of 0.5 mM and a temperature of 303 K. To elucidate the interaction between the inhibitor and the mild steel surface, we applied the Langmuir adsorption isotherm concept, shedding light on both the physical and chemical adsorption processes of the thiophene derivative on the metal's surface. Our investigations demonstrated that the addition of the inhibitor significantly reduced the corrosion rate of the metal. Our computational results further reinforced these experimental findings, indicating that the inhibitor formed stable adsorption complexes on the metal surface. This dual confirmation from experimental and computational approaches strengthens the confidence in the inhibitor's efficacy in mitigating corrosion.

Summary: Depolymerization and upcycling are promising approaches to managing plastic waste. However, quantitative measurements of reaction rates and analyses of complex product mixtures arising from depolymerization of polyolefins constitute significant challenges in this emerging field. Here, we detail techniques for recovery and analysis of products arising from batch depolymerization of polyethylene. We also describe quantitative analyses of reaction rates and products selectivity. This protocol can be extended to depolymerization of other plastics and characterization of other product mixtures including long-chain olefins.For complete details on the use and execution of this protocol, please refer to Sun et al.1 : Publisher’s note: Undertaking any experimental protocol requires adherence to local institutional guidelines for laboratory safety and ethics.

In this paper, a dual-band six-way power divider is designed with equal and unequal power division capabilities. The unequal design of the divider is capable of providing up to four different output levels at each band. Furthermore, it is capable of achieving band-distinct power division ratios. These capabilities are realized in the proposed divider by using dual-band pi-shaped impedance transformers. The S-parameters of the proposed divider are derived analytically, and its design procedure is explained in detail. Four prototypes operating at 0.9/1.4 GHz are designed and fabricated to demonstrate the divider’s capabilities. Simulation and measurements results of the four prototypes are presented. The measured output power levels of the four prototypes at each band are within 1 dB from their theoretical values. Also, good input matching (

Abstract Background Most mass gathering events have been suspended due to the SARS-CoV-2 pandemic. However, with vaccination rollout, whether and how to organize some of these mass gathering events arises as part of the pandemic recovery discussions, and this calls for decision support tools. The Hajj, one of the world's largest religious gatherings, was substantively scaled down in 2020 and 2021 and it is still unclear how it will take place in 2022 and subsequent years. Simulating disease transmission dynamics during the Hajj season under different conditions can provide some insights for better decision-making. Most disease risk assessment models require data on the number and nature of possible close contacts between individuals. Methods We sought to use integrated agent-based modeling and discrete events simulation techniques to capture risky contacts among the pilgrims and assess different scenarios in one of the Hajj major sites, namely Masjid-Al-Haram. Results The simulation results showed that a plethora of risky contacts may occur during the rituals. Also, as the total number of pilgrims increases at each site, the number of risky contacts increases, and physical distancing measures may be challenging to maintain beyond a certain number of pilgrims in the site. Conclusions This study presented a simulation tool that can be relevant for the risk assessment of a variety of (respiratory) infectious diseases, in addition to COVID-19 in the Hajj season. This tool can be expanded to include other contributing elements of disease transmission to quantify the risk of the mass gathering events.

A heuristic evaluation ‎ model is proposed for assessing the usability of the Top 10 Iraq university websites. ‎This model is based on 3 hierarchies of website usability criteria levels. The top hierarchy level consists of five website categories: design and layout, learnability, content, performance, and errors. In the middle hierarchy level 18 subcategories, and in the bottom hierarchy level 44 elements were described. The evaluation model utilized both automated tools and observation methods. To validate the results obtained by the proposed model, the selected universities were evaluated and scored according to the usability criteria of their websites. Besides the observation elements, the four automated tools (thinkwithgoogle, gtmetrix, tools. Pingdom, and webpagetest) were also used to assess the error and performance of the websites. The study showed that except for the University of Kufa and Baghdad University websites, the rest of the university websites failed to meet the applied website usability criteria levels of the proposed evaluation model.

Mupirocin is an antibacterial agent that has been documented to be effective in treating superficial skin infections. However, the main limitation of its application is bacterial resistance. Therefore, there is a need to determine a way to potentiate its efficiency. Accordingly, this obstacle led to this current investigation, which aims to find a way to improve the therapeutic action of mupirocin. This study focuses on the integration of tea tree oil with mupirocin to improve its antibacterial and wound healing capacities. Distinct nanoemulsions (NEs) were developed and the best of them were optimized using a central composite design (CCD) approach. The optimized NEs were mixed with a gel base to form a mupirocin-loaded nanoemulgel (NEG). The formulation was evaluated for characteristics including pH, viscosity, spreadability, and in vitro release over 6 h. The NEG was examined for its stability in two different conditions, namely at room temperature and refrigerated, for 3 months. Eventually, the NEG was inspected to determine its antibacterial and wound healing efficiencies. The developed mupirocin-loaded NEG exhibited good physical properties in terms of pH (6.13), viscosity (19,990 cP), spreadability (48.8 mm), and in vitro release over 6 h (51.4%). Moreover, it showed good stability with no significant difference in the evaluated parameters when stored for 3 months in the two conditions. Ultimately, mupirocin-loaded NEG prepared with tea tree oil exhibited a significant antibacterial influence in addition to good healing efficiency.

The corrosion inhibition potency of 1-(2-ethylamino-1,3,4-thiadiazol-5-yl)-3-phenyl-3-oxopropan (ETO) for mild steel in 1.0 M hydrochloric acid was investigated by applying weight loss techniques, and quantum chemical calculations. Conditions that determine the potential for corrosion inhibition, including; concentration, the structure of ETO, and solution temperature, were chosen for the study. The highest inhibitive efficacy of ETO was 98.4%, at the optimum concentration (500 ppm) and room temperature. ETO has superior corrosion inhibitive potency in the HCl environment, owing to the presence of the thiadiazole and benzene rings, in addition to carbonyl and amino groups. Applicable thermodynamical equations were used to calculate the activation energy, enthalpy, and entropy. The adsorption isotherms were applied to determine the Gibbs free energy difference. The experimental findings of the investigation revealed that the activation energy of an inhibited process was higher than for an uninhibited process. Furthermore, the increased inhibition efficiency with improving temperature, and the values of ΔGo, indicated that ETO molecules coated the mild steel surface in both chemical adsorption and physical interactions. The adsorption process on the mild steel surface obeys the Langmuir adsorption isotherm. Both experimental and density functional theory (DFT) findings in the current investigation are in excellent agreement.

Background: Type 2 diabetes mellitus (T2DM) is a leading cause of mortality and morbidity worldwide. Leptin, an adipokine with the primary function of regulating energy balance, is found to mediate insulin secretion and sensitivity in peripheral tissues. Aims: Hence, we aimed to determine the role of leptin in the development of insulin resistance (IR) in newly diagnosed T2DM patients and determine tumor necrosis factoralpha (TNF-?). Materials and methods: A case control study a total of 80 patients and 50 control groups, used Cobas E311 device to measure glucose, whereas HbA1c used D-10 hemoglobin Hba1c device whereas other parameters used ELISA methods were used to analyses 130 samples Results: Highly significant increase level of Fasting blood sugar, hemoglobin A1c, Insulin, Leptin and HOMA- insulin resistance whereas significant decrease level of TNF alpha and , Plasminogen activator inhibitors -1 in patient type two diabetes mellitus compared to the control group. Conclusion: increased the level of leptin levels while TNF-? levels were decreased in type 2 diabetes patients.

Background: The inflammatory mediators released by injured endothelium enhance the interaction of circulating leukocytes with endothelial cells and contribute to development and progression of atherosclerosis. In this study we designed to determine some interleukins (IL-1?, IL-5, IL-6 and IL-8) as diagnostic markers instable angina pectoris. Methods: The study was carried out on 30 patients who were diagnosed with stable angina pectoris (18 males and 12 females).They visited Nasiriya Heart Center throughout the period from the beginning of November 2021 to the end of April 2022, and 20 age matched healthy person (13 males and 7 females). IL-1?, IL-5, IL-6, IL-8 were assayed by an enzyme-linked immunosorbent assay (ELISA). Troponin I (cTnl) was determined by using monoclonal cTnI-specific antibody. D- dimer by electro-chemiluminescence method. CK-MB by monoclonal CK-MB-specific antibody. Myoglobin by monoclonal MYO-specific antibody. Results: Male and female patients with stable angina showed significantly elevated serum levels of troponin (P

Geotechnical structures made of granular material tend to be unsaturated during their service life. However, there is presently a lack of sufficient research and studies on their volumetric behavior under unsaturated conditions. In this study, loading and wetting induced volumetric behavior of granular materials in the unsaturated state was studied within a moisture content-based framework. Recycled crushed brick (CB) and excavation waste rock (WR) were the granular materials used in this research to promote sustainable construction. Several loading, unloading, and wetting state paths were investigated with respect to virgin compaction surfaces (VCS) developed using groups of compaction curves. The obtained experimental data was utilized to develop a constitutive model capable of predicting wetting-induced volume changes of granular materials in a net stress range of 100–4000 kPa and gravimetric moisture content range of 3.6% for WR, and 7.5% for CB to saturation. The model was verified by undertaking several independent state paths on independent materials and comparing the experimental responses with those predicted using the model. The proposed model is featured with simplicity in acquiring the model input parameters with the aim of filling the existing gap between the theoretical and real-life application of unsaturated soil mechanics. An application of the model can be the basis for the prediction of the settlement of a granular geotechnical structure that is being externally loaded and is subject to changes in moisture content due to climatic effects.

Abstract Background School testing for SARS-CoV-2 infection has become an important policy and planning issue as schools were reopened after the summer season and as the COVID-19 pandemic continues. Decisions to test or not to test and, if testing, how many tests, how often and for how long, are complex decisions that need to be taken under uncertainty and conflicting pressures from various stakeholders. Method We have developed an agent-based model and simulation tool that can be used to analyze the outcomes and effectiveness of different testing strategies and scenarios in schools with various number of classrooms and class sizes. We have applied a modified version of a standard SEIR disease transmission model that includes symptomatic and asymptomatic infectious populations, and that incorporates feasible public health measures. We also incorporated a pre-symptomatic phase for symptomatic cases. Every day, a random number of students in each class are tested. If they tested positive, they are placed in self-isolation at home when the test results are provided. Last but not least, we have included options to allow for full testing or complete self-isolation of a classroom with a positive case. Results We present sample simulation results for parameter values based on schools and disease related information, in the Province of Ontario, Canada. The findings show that testing can be an effective method in controlling the SARS-CoV-2 infection in schools if taken frequently, with expedited test results and self-isolation of infected students at home. Conclusions Our findings show that while testing cannot eliminate the risk and has its own challenges, it can significantly control outbreaks when combined with other measures, such as masks and other protective measures.

For the development effective and successful mobile learning applications, it is important to understand the users' requirements in different stages of usage. In this paper, we developed a new model to study the effect of different factors on mobile learning applications development at the three main stages of usage (static stage, interaction stage and transaction stage). The results of this study showed that each stage of the three stages, static, interaction, and transaction has different requirements in terms of system compatibility, security, information quality, awareness, perceived functional benefit, self-efficacy, perceived image, perceived uncertainty, availability of resources, and perceived trust. In addition, the results demonstrated that the requirements and perceptions of users towards the adoption and use of mobile learning application in the three stages significantly differ. The novelty of this research will be an added value to the body of knowledge and its implications will be vital for researchers and designers who are developing mobile learning applications.

This study aimed to alleviate the gap between the literature regarding the Social Networking Applications (SNAs) use for active collaboration and engagement as sustainability in higher education and task-technology-fit (TTF) and compatibility on their consequence on students' satisfaction and their performance impact its sustainability used in higher education. Although researchers have examined (SNAs) usage within multiple situations, the roles of (TTF) and compatibility as mediating variables have not been investigated through TAM model and constructivism theory on measuring education sustainability. Overall 602 students and researchers took part in this study, which were selected from public university. Using the method of structural equation modeling (SEM), we surveyed to discover the perception of students toward the (SNAs). Based on the results, the (SNAs) use for collaboration and engagement as sustainability in higher education, and TTF and compatibility positively impacted the student's learning performance on measuring education sustainability, and they were found to be completely pleased with the perceived ease of use and perceived usefulness. In conclusion, the role of TTF and compatibility presents positive influences performances related to sustainability for education; and both factors mediates associations among collaboration and engagement as sustainability in higher education, students' satisfaction on (SNAs) usage and students' performance related to sustainability for education. Therefore, their impact should be encouraged in learning processes in higher education institutions.

Prosopis farctais belonged to Mimosaceae family, commonly known as mesquite. It was chosen to investigate their effect on α-glucosidase inhibitory activity (in-vitro), serum glucose and liver functions. Roots, fruits, and leaves of P. farcta, were extracted by n-hexane, ethyl acetate, and methanol. α-glucosidase inhibition was analyzed by using ELISA technique then half maximal inhibitory concentration IC50 was found. The blood glucose levels were determined with a glucose analyzer model. The serum alkaline phosphatase (ALP), Alanine transaminase (ALT), aspartate aminotransferase (AST) and serum total bilirubin (TB) were estimated by using the Cobas diagnostic kit with a fully automated chemical analyzer. Diabetes was done by a single dose of 120 mg alloxan/kg b.w with subcutaneously injection. Ethyl acetate extracts of P. farcta showed the higher α-glucosidase inhibitory activity, and the best one was root extract. Treatments of the alloxan-induced diabetes rats were done by daily oral administration of different concentrations with P. farcta extracts of ethyl acetate for 28 days and the dose 200 mg/kg BW was the effective one. The root extract was the best one for reduction of serum glucose followed by leaves then fruits. Administration of root extract of P. farcta showed a decrease in the levels of ALP and TB in alloxan-induced diabetes rats. The fruit extract of P. farcta showed decreasing in the level of ALP in alloxan-induced diabetes rats. In conclusion, the P. farcta extracts for ethyl acetate have properties of hypoglycemic effect as well as improving some parameters related with diabetic complications of liver functions.

OBJECTIVES/BACKGROUND:. Extracorporeal membrane oxygenation is used as rescue therapy for patients with acute respiratory distress syndrome in whom conventional therapy has failed prior to an Extra Corporeal Membrane Oxygenator to rescue Lung Injury in Severe Acute Respiratory Distress Syndrome trial. Since then, extracorporeal membrane oxygenation has been incorporated as part of the standard treatment algorithm in many centers for patients with severe acute respiratory distress syndrome. Since the emergence of coronavirus disease 2019 in early 2020, extracorporeal membrane oxygenation has been used effectively as rescue therapy and as a bridge to recovery in some patients with refractory respiratory failure. DESIGN, SUBJECT, AND INTERVENTION:. We present a 38-year-old male healthcare worker diagnosed with coronavirus disease 2019 and progressed to critical condition with severe surgical emphysema on a high-flow nasal cannula with Fio2 100%, a flow of 40 L/min, and a maximum oxygen saturation of 88%. He was successfully treated by applying awake extracorporeal membrane oxygenation, without a need for invasive mechanical ventilation, to avoid worsening barotrauma and hemodynamic compromise potentially induced by positive pressure ventilation. MAIN RESULTS AND CONCLUSIONS:. To our knowledge, this is one of the first cases to be reported in the literature on the use of awake extracorporeal membrane oxygenation as a “treatment” for barotrauma due to severe acute respiratory distress syndrome in a coronavirus disease 2019 patient, without the need for invasive mechanical ventilation. In selected patients with severe respiratory failure, awake extracorporeal membrane oxygenation can be used as a salvage treatment and obviate the need for invasive mechanical ventilation.

Abstract Background Low-temperature swelling of cotton linter cellulose and subsequent gelatinization in trifluoroacetic acid (TFA) greatly enhance rates of enzymatic digestion or maleic acid–AlCl3 catalyzed conversion to hydroxymethylfurfural (HMF) and levulinic acid (LA). However, lignin inhibits low-temperature swelling of TFA-treated intact wood particles from hybrid poplar (Populus tremula × P. alba) and results in greatly reduced yields of glucose or catalytic conversion compared to lignin-free cellulose. Previous studies have established that wood particles from transgenic lines of hybrid poplar with high syringyl (S) lignin content give greater glucose yields following enzymatic digestion. Results Low-temperature (− 20 °C) treatment of S-lignin-rich poplar wood particles in TFA slightly increased yields of glucose from enzymatic digestions and HMF and LA from maleic acid–AlCl3 catalysis. Subsequent gelatinization at 55 °C resulted in over 80% digestion of cellulose in only 3 to 6 h with high-S-lignin wood, compared to 20–60% digestion in the wild-type poplar hybrid and transgenic lines high in guaiacyl lignin or 5-hydroxy-G lignin. Disassembly of lignin in woody particles by Ni/C catalytic systems improved yields of glucose by enzymatic digestion or catalytic conversion to HMF and LA. Although lignin was completely removed by Ni/C-catalyzed delignification (CDL) treatment, recalcitrance to enzymatic digestion of cellulose from the high-S lines was reduced compared to other lignin variants. However, cellulose still exhibited considerable recalcitrance to complete enzymatic digestion or catalytic conversion after complete delignification. Low-temperature swelling of the CDL-treated wood particles in TFA resulted in nearly complete enzymatic hydrolysis, regardless of original lignin composition. Conclusions Genetic modification of lignin composition can enhance the portfolio of aromatic products obtained from lignocellulosic biomass while promoting disassembly into biofuel and bioproduct substrates. CDL enhances rates of enzymatic digestion and chemical conversion, but cellulose remains intrinsically recalcitrant. Cold TFA is sufficient to overcome this recalcitrance after CDL treatment. Our results inform a ‘no carbon left behind’ strategy to convert total woody biomass into lignin, cellulose, and hemicellulose value streams for the future biorefinery.

This paper attempts to mitigate this gap within the literature concerning the use of social media for cyber engagement (CE) among students. Since students often become upset when network providers intervene, this paper aims to develop a model to measure ethics issues related to engagement with social media. The conducted survey examines social media use with regard to cyber engagement, cyberbullying behaviors, and being bullied, harassed, and stalked. To achieve the objective, this paper employed a questionnaire as the main data collection method and distributed it to 242 students, all of whom use social media. The findings were obtained via a quantitative research method, structural equation modeling, and partial least squares. The findings from our empirical study indicate that the assessment of discriminant validity has become an extensively acknowledged requirement for the analysis of latent variables’ relationships. Goodness of fit indices demonstrates a good fit of the model. Roughly more than half of students indicated they had been bullied, harassed, and stalked online. The proposed model will help campus administration and decision makers to formulate strategies that can significantly reduce cyber harassment among students.

This paper aims to explore and investigate the potential factors influencing students' behavioral intentions to use the e-learning system. This paper proposes an extended technology acceptance model (TAM) that has been tested and examined through the use of both innovation diffusion theory (IDT) and integrating TAM. This paper was conducted on 1286 students utilizing systems of e-learning in Malaysia. The findings were obtained via a quantitative research method. The findings illustrate that six perceptions of innovation characteristics, in particular, have impacts on students' e-learning system behavioral intention. The influences of the relative advantages, observability, trialability, perceived compatibility, complexity, and perceived enjoyment on the perceived ease of use is noteworthy. Moreover, the effects of the relative advantages, complexity, trialability, observability, perceived compatibility, and perceived enjoyment on the perceived usefulness have a strong impact. Therefore, the empirical results provide strong backing to the integrative approach between TAM and IDT. The findings suggest an extended model of TAM with IDT for the acceptance of the e-learning system used to improve the students' learning performance, which can help decision makers in higher education, universities, as well as colleges to evaluate, plan and execute the use of e-learning systems.

This paper aims to bridge the literature gap concerning the use of social media to conduct collaboration learning and explore its effect on student performance through cyberstalking (CS) and cyberbullying (CB). To achieve the study objective, this study employed a questionnaire as the main data collection method and distributed it to 538 university students based on both the technology acceptance model and constructivism theory, all of whom use social media. The findings were obtained via a quantitative research method, structural equation modeling. This study found a significant relationship between perceived usefulness, perceived ease of use, and perceived enjoyment with social media use for open learning. However, this study found a negative relationship from social media use on open learning that was dampened by CB, which is considered a dampening factor. Also, open learning was reported to be negatively influenced by perceived usefulness as CS was found to dampen the relationship with open learning.

Mobile learning applications have been growing in demand and popularity and have become a common phenomenon in modern educational systems, especially with the implementation of mobile learning projects. This study applies the Unified Theory of Acceptance and Use Technology (UTAUT) model to examine the effects of different factors that were identified from the literature on students' acceptance of mobile learning applications in higher education. The data was collected from a 697 university students responded to an online questionnaire. SEM method was used for data analysis. The results showed that perceived information quality, perceived compatibility, perceived trust, perceived awareness, and availability of resources, self-efficacy, and perceived security are the main motivators of students' acceptance of mobile learning system, and consequently success the implementation of mobile learning projects. Results from this study provide the necessary information as to how higher education institutions can enhance students' acceptance of mobile learning system in order to support the usage of mobile technologies in learning and teaching process. These results offer important implications for mobile learning acceptance and usage.

Self-amplified spontaneous-emission (SASE) free-electron lasers (FELs) deliver ultrashort pulses with femtosecond durations. Due to the fluctuating nature of the radiation properties of SASE FELs, characterizing FEL pulses on a single-shot basis is necessary. Therefore, we use terahertz streaking to characterize the temporal properties of ultrashort extreme ultraviolet pulses from the free-electron laser in Hamburg (FLASH). In this study, pulse duration as well as pulse energy are measured in a wavelength range from 8 to 34 nm as functions of undulators contributing to the lasing process. The results are compared to one-dimensional and three-dimensional, time-dependent FEL simulations.

Using traditional weight-loss tests, as well as different electrochemical techniques (potentiodynamic polarization and electrochemical impedance spectroscopy), we investigated the corrosion-inhibition performance of 2,2′-(1,4-phenylenebis(methanylylidene)) bis(N-(3-methoxyphenyl) hydrazinecarbothioamide) (PMBMH) as an inhibitor for mild steel in a 1 M hydrochloric acid solution. The maximum protection efficacy of 0.0005 M of PMBMH was 95%. Due to the creation of a protective adsorption layer instead of the adsorbed H2O molecules and acidic chloride ions, the existence of the investigated inhibitor reduced the corrosion rate and increased the inhibitory efficacy. The inhibition efficiency increased as the inhibitor concentration increased, but it decreased as the temperature increased. The PMBMH adsorption mode followed the Langmuir adsorption isotherm, with high adsorption-inhibition activity. Furthermore, the value of the ∆Gadso indicated that PMBMH contributed to the physical and chemical adsorption onto the mild-steel surface. Moreover, density functional theory (DFT) helped in the calculation of the quantum chemical parameters for finding the correlation between the inhibition activity and the molecular structure. The experimental and theoretical findings in this investigation are in good agreement.

The COVID-19 pandemic has been particularly threatening to patients with end-stage kidney disease (ESKD) on intermittent hemodialysis and their care providers. Hemodialysis patients who receive life-sustaining medical therapy in healthcare settings, face unique challenges as they need to be at a dialysis unit three or more times a week, where they are confined to specific settings and tended to by dialysis nurses and staff with physical interaction and in close proximity. Despite the importance and critical situation of the dialysis units, modelling studies of the SARS-CoV-2 spread in these settings are very limited. In this paper, we have used a combination of discrete event and agent-based simulation models, to study the operations of a typical large dialysis unit and generate contact matrices to examine outbreak scenarios. We present the details of the contact matrix generation process and demonstrate how the simulation calculates a micro-scale contact matrix comprising the number and duration of contacts at a micro-scale time step. We have used the contacts matrix in an agent-based model to predict disease transmission under different scenarios. The results show that micro-simulation can be used to estimate contact matrices, which can be used effectively for disease modelling in dialysis and similar settings.

The use of N-2-methylbenzylidene-4-antipyrineamine as an acid corrosion inhibitor for mild steel surfaces in hydrochloric acid is discussed in this article by means of weight loss, electrochemical impedance spectroscopy (EIS), and scanning electron microscopy (SEM) methods. The experimental findings exhibited that N-2-methylbenzylidene-4-antipyrineamine is a significant corrosion inhibitor for the mild steel in 1.0 M HCl solution and that its protection efficiency touches the peak at 5 × 10–4 M, exhibiting 91.8% for N-2-methylbenzylidene-4-antipyrineamine. The inhibitory efficiency increases as the inhibitor concentration rises and reduces as the temperature rises. Temperature has a significant impact on corrosion and blocking activities, which is extensively examined and explained. According to the gravimetric results, the examined inhibitor inhibits mild steel surface corrosion by providing a barrier at the metal–hydrochloric acid medium interface. Thermodynamic characteristics were combined with a quantum chemistry investigation using density functional theory to provide more insight into the inhibitory effect mechanism. The tested inhibitor adsorbs on the mild steel surface based on Langmuir’s adsorption isotherm method.

Towards the utilization of different parts of date palm biomass waste, low-concentration acid-alkali treatment was used to isolate the contained cellulose and α-cellulose. The cellulose yields achieved from the rachis, leaflet, and fiber parts of the biomass were 74.70%, 71.50%, and 73.82%, respectively, while the corresponding α-cellulose yields were 78.63%, 75.64%, and 70.40%, respectively. The cellulose samples were bleached and characterized by thermogravimetric analysis (TGA), Fourier-transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), and X-ray diffraction (XRD). The XRD results revealed high crystallinity of both the cellulose and α-cellulose samples, while the TGA thermograms indicated that the alkali treatment completely removed lignin and hemicelluloses from the rachis. The results of this study demonstrate the promise of using date palm biomass waste as raw material to produce cellulose and α-cellulose.

Social media users can be negatively affected by cyber harassment. These effects can cause emotional distress and lead people to stop using social network sites or to end their life. In addition, the users of this technology usually get upset when network providers interfere and consider such interference to be unfair. Therefore, this paper attempted to mitigate the gap in the literature concerning the use of social media for engaging in cyber harassment in the context of higher education. Therefore, the main objective was to develop a model that will bridge this gap. The model developed in this paper is based on the unified theory of acceptance and use of technology, theory of planned behavior, and technology support. To achieve the study's objectives, a questionnaire was used as the main data collection method, and it was distributed to 340 students who used social media. This paper argues that these decisions of interference can be handled by employing a method that users find sufficient and appropriate. In conclusion, this research specifically proposes a model for identifying the significant factors that are anticipated to play major roles in minimizing cyber harassment among Saudi students. The proposed model will help administrations and decision makers to formulate strategies that can significantly affect anti-cyber harassment among students.

A triazole heterocyclic compound namely 3-(4-ethyl-5-mercapto-1, 2, 4-triazol-3-yl)-1-phenylpropanone (EMTP) was examined for its corrosion protection of mild steel (MS) against 1 M hydrochloric acid medium using gravimetric techniques. EMTP exhibited excellent corrosion protection performance at low and high concentrations towards MS in HCl solution. Comparison of corrosion protection performance of EMTP and its parent triazole and temperature effects of on inhibition efficacy were also studied. EMTP has potential corrosion inhibitor for mild steel in 1.0 M hydrochloric acid solution with the highest protection efficacy of 97% at 303 K. The weight loss findings implied that EMTP protects the metal surface corrosion through the creation of a protective layer at the surface mild steel–corrosive solution interface. The inhibitive efficacy increases with the increase of inhibitor concentration and decreases with increased temperature. The adsorption of EMTP on the surface of MS follows Langmuir’s adsorption isotherm process. DFT method was conducted on EMTP molecule to calculate the quantum chemical parameters and to determine the relationship between the molecular structure of EMTP and protection performance. The molecular parameters, such as energy gap and frontier molecular orbital (highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO)), and the absolute electronegativity (χ) value from inhibitor molecules to unoccupied d-orbital of iron atoms on the mild steel surface were also determined and correlated with protection efficiency. The theoretical findings revealed that the protection performance of EMTP increased with the increase in HOMO energy, and the nitrogen, oxygen and sulfur atoms are most probable positions for bonding through giving electrons to the d-orbital of iron atoms on the mild steel surface.

The understanding of the public response to COVID-19 vaccines is the key success factor to control the COVID-19 pandemic. To understand the public response, there is a need to explore public opinion. Traditional surveys are expensive and time-consuming, address limited health topics, and obtain small-scale data. Twitter can provide a great opportunity to understand public opinion regarding COVID-19 vaccines. The current study proposes an approach using computational and human coding methods to collect and analyze a large number of tweets to provide a wider perspective on the COVID-19 vaccine. This study identifies the sentiment of tweets using a machine learning rule-based approach, discovers major topics, explores temporal trend and compares topics of negative and non-negative tweets using statistical tests, and discloses top topics of tweets having negative and non-negative sentiment. Our findings show that the negative sentiment regarding the COVID-19 vaccine had a decreasing trend between November 2020 and February 2021. We found Twitter users have discussed a wide range of topics from vaccination sites to the 2020 U.S. election between November 2020 and February 2021. The findings show that there was a significant difference between tweets having negative and non-negative sentiment regarding the weight of most topics. Our results also indicate that the negative and non-negative tweets had different topic priorities and focuses. This research illustrates that Twitter data can be used to explore public opinion regarding the COVID-19 vaccine.

Abstract Background Mass drug administration (MDA) appears to be effective in reducing the risk of malaria parasitaemia. This study reports on programmatic coverage and compliance of MDA using artemisinin-based combination therapy (ACT) in four shehias (smallest administration unit) that had been identified as hotspots through Zanzibar’s malaria case notification surveillance system. Methods Mass drug administration was done in four shehias selected on the basis of: being an established malaria hot spot; having had mass screening and treatment (MSaT) 2–6 weeks previously; and exceeding the epidemic alert threshold of 5 cases within a week even after MSaT. Communities were sensitized and MDA was conducted using a house-to-house approach. All household members, except pregnant women and children aged less than 2 months, were provided with ACT medicine. Two weeks after the MDA campaign, a survey was undertaken to investigate completion of ACT doses. Results A total of 8816 [97.1% of eligible; 95% confidence interval (CI) 96.8–97.5] people received ACT. During post MDA surveys, 2009 people were interviewed: 90.2% reported having completed MDA doses; 1.9% started treatment but did not complete dosage; 4.7% did not take treatment; 2.0% were absent during MDA and 1.2% were ineligible (i.e. infants

This study is dedicated to the research of vocabulary learning strategies (VLSs) employed by a group of Saudi Arabian learners in an EFL (English as a foreign language) context. The rationale for the study is to clarify a pronounced lack of research on the EFL context in Saudi Schools Abroad (SSA), and a dearth of prior research into VLSs in this context. In particular, this research intends to explore how do students at Saudi School Malaysia (SSM) employ VLSs in their actual learning process. Therefore, this study is conducted on cognitive theory of learning studies, the mental processes involved in the learning process. Moreover, this study conducted an analysis of studies dedicated to VLSs through secondary students at Saudi school in Malaysia based on previous research problems of models and theories. In addition, this study applied quantitative approach, and the questionnaire was conducted using 105 students. The results of this study revealed the percentage and frequency have further underscored this role and the significance of vocabulary learning in both students and teachers. Also, the results show that students at SSM have employed the five categories of VLSs at a medium level and almost at a close range.

Hydrogenation of succinic acid and maleic acid produces C4 value-added chemicals such as γ-butyrolactone and tetrahydrofuran. Here, unsupported ReOx nanoparticles transform succinic acid to γ-butyrolactone and tetrahydrofuran via catalytic transfer hydrogenation with isopropanol as a liquid phase hydrogen donor. This catalyst is also active for the sequential reaction of deoxydehydration and transfer hydrogenation in isopropanol, synthesizing renewable succinic acid and its esters from tartaric acid. One-step conversion of tartaric acid to γ-butyrolactone is achieved in a moderate yield and the possible reaction pathway is discussed.

Using the thermalgravimetric technique, we investigated the non-isothermal combustion kinetics of abundant and low-cost date palm wastes (leaflet, rachis, fibers, and their composite) as potential biomass energy sources. The kinetic and thermodynamic parameters were determined by Flynn–Wall–Ozawa (FWO), Kissinger–Akahila–Sunose (KAS), and Starink methods. Thermogravimetric analysis results showed a major peak for the degradation of volatiles between 127–138 °C with average percentage mass loss of 68.04 ± 1.5, 65.57 ± 0.6, 62.97 ± 5.5, and 59.26 ± 3.2, for rachis, composite, leaflet, and fibers, respectively. The FWO model showed the lowest activation energy, Eα, of 157 ± 25.6, 158 ± 25.7, 164 ± 40.1, and 169 ± 51.8 kJ mol−1 for the composite, rachis, leaflet, and fibers, respectively. The positive enthalpy values confirmed an endothermic pyrolysis reaction. For all models, a minimal difference of 4.40, 5.57, 6.55, and 7.51 kJ mol−1 between activation energy and enthalpy for rachis, fibers, composite, and leaflet ensued, respectively. The KAS model was best suited to describe chemical equilibrium with average ΔG values of 90.3 ± 28.8, 99.3 ± 34.9, 178.9 ± 27.3, and 186.5 ± 38.2 kJ mol−1 for rachis, fibers, composite, and leaflet, respectively. The reaction mechanism by the Malek and Popescu methods was ((g(α)=[−ln(1−α)]14) across the conversion range of 0.1–0.9 for all heating rates. The high energy content and volatile matter combined with low energy barriers make date palm waste a potential candidate in a biorefinery.

Abstract Background Indoor residual spraying (IRS) of households with insecticide is a principal malaria vector control intervention in Zanzibar. In 2006, IRS using the pyrethroid lambda-cyhalothrine was introduced in Zanzibar. Following detection of pyrethroid resistance in 2010, an insecticide resistance management plan was proposed, and IRS using bendiocarb was started in 2011. In 2014, bendiocarb was replaced by pirimiphos methyl. This study investigated the residual efficacy of pirimiphos methyl (Actellic® 300CS) sprayed on common surfaces of human dwellings in Zanzibar. Methods The residual activity of Actellic 300CS was determined over 9 months through bioassay tests that measured the mortality of female Anopheles mosquitoes, exposed to sprayed surfaces under a WHO cone. The wall surfaces included; mud wall, oil or water painted walls, lime washed wall, un-plastered cement block wall and stone blocks. Insecticide susceptibility testing was done to investigate the resistance status of local malaria vectors against Actellic 300CS using WHO protocols; Anopheline species were identified using PCR methods. Results Baseline tests conducted one-day post-IRS revealed 100 % mortality on all sprayed surfaces. The residual efficacy of Actellic 300CS was maintained on all sprayed surfaces up to 8 months post-IRS. However, the bioassay test conducted 9 months post-IRS showed the 24 h mortality rate to be ≤80 % for lime wash, mud wall, water paint and stone block surfaces. Only oil paint surface retained the recommended residual efficacy beyond 9 months post-IRS, with mortality maintained at ≥97 %. Results of susceptibility tests showed that malaria vectors in Zanzibar were fully (100 %) susceptible to Actellic 300CS. The predominant mosquito vector species was An. arabiensis (76.0 %) in Pemba and An. gambiae (83.5 %) in Unguja. Conclusion The microencapsulated formulation of pirimiphos methyl (Actellic 300CS) is a highly effective and appropriate insecticide for IRS use in Zanzibar as it showed a relatively prolonged residual activity compared to other products used for the same purpose. The insecticide extends the residual effect of IRS thereby making it possible to effectively protect communities with a single annual spray round reducing overall costs. The insecticide proved to be a useful alternative in insecticide resistance management plans.

Abstract Background Bendiocarb was introduced for the first time for Indoor Residual Spraying (IRS) in Tanzania in 2012 as part of the interim national insecticide resistance management plan. This move followed reports of increasingly alarming levels of pyrethroid resistance across the country. This study used the insecticide quantification kit (IQK) to investigate the intra-operational IRS coverage and quality of spraying, and decay rate of bendiocarb on different wall surfaces in Kagera region. Methods To assess intra-operational IRS coverage and quality of spraying, 104 houses were randomly selected out of 161,414 sprayed houses. A total of 509 samples (218 in Muleba and 291 in Karagwe) were obtained by scraping the insecticide samples from wall surfaces. To investigate decay rate, 66 houses (36 in Muleba and 30 in Karagwe) were selected and samples were collected monthly for a period of five months. Laboratory testing of insecticide concentration was done using IQKTM [Innovative Vector Control Consortium]. Results Of the 509 samples, 89.5% met the World Health Organization (WHO) recommended concentration (between 100–400 mg/m2) for IRS target dosage. The proportion of samples meeting WHO standards varied between Karagwe (84.3%) and Muleba (96.3%) (p

Abstract Background The type of sprayable surface impacts on residual efficacy of insecticide used in indoor residual spraying (IRS). However, there is limited data on common types of wall surfaces sprayed in Zanzibar and mainland Tanzania where IRS began in 2006 and 2007 respectively. The study investigated residual efficacy of micro-encapsulated lambda-cyhalothrin sprayed on common surfaces of human dwellings and domestic animal shelters in Zanzibar and mainland Tanzania. Methods An experimental hut was constructed with different types of materials simulating common sprayable surfaces in Zanzibar and mainland Tanzania. Surfaces included cement plastered wall, mud-daub, white-wash, wood, palm-thatch, galvanized iron-sheets, burnt-bricks, limestone and oil-paint. The World Health Organization (WHO) procedure for IRS was used to spray lambda-cyhalothrin on surfaces at the dose of 20–25 mg/m2. Residual efficacy of insecticide was monitored through cone bioassay using laboratory-reared mosquitoes; Kisumu strain (R–70) of Anopheles gambiae ss. Cone bioassay was done every fortnight for a period of 152 days. The WHO Pesticide Evaluation Scheme (WHOPES) threshold (80% mortality) was used as cut-off point for acceptable residual efficacy. Results A total of 5,800 mosquitoes were subjected to contact cone bioassay to test residual efficacy of lambda-cyhalothrin. There was a statistically significant variation in residual efficacy between the different types of wall surfaces (r = 0.24; p 20% of sprayable structures, two rounds of IRS using lambda-cyhalothrin should be considered. Further studies are required to investigate the impact of sprayable surfaces on residual efficacy of other insecticides commonly used for IRS in Zanzibar and mainland Tanzania.