Assessing the usability of virtual learning environments in higher education

Context: E-learning is an integral part of the modern higher education system, and therefore it is essential that students and staff are able to use systems that support E-learning, such as Virtual Learning Environments (VLEs), effectively. Usability is essential to ensure effective use of these systems and is often assessed by means of subjective questions. Although developed mainly for industry use, the Technology Acceptance Model (TAM) and System Usability Scale (SUS) questionnaire are often used to assess E-learning systems. Goal: The main goal of this thesis is to assess the usability of a VLE platform currently used in universities (Blackboard) and identify the most common and appropriate methods used to assess a VLE platform’s usability. Another aim is to investigate whether there are extensions to common usability models and methods (such as the SUS and TAM) that could improve their accuracy, including the potential of combining them with more objective measures such as number of clicks, time taken and open-ended questions. Method: The literature on VLE usability evaluation was reviewed using a mapping study methodology to identify the usability methods and factors that have been used previously. Informed by the findings of this study, a set of usability questionnaires have been developed, used and evaluated, with 101 student respondents recruited from all the Schools at Keele University participating in the first study (Chapter Four) and 162 in the second study (Chapter Five). A standard usability questionnaire and a novel form of observation were then combined to record 25 participants’ interactions with the VLE (Chapter Six) while they completed a set of representative tasks in two sessions that were held eight weeks apart. These interactions were then compared. Results: The results indicate that the VLE performed below the average usability expectation score (SUS score of 62.52) but is still considered as ‘acceptable’. Twenty-seven free text responses were also obtained in the first study and a thematic analysis of comments revealed very negative views of the VLE as well as areas for improvement. In the second study, it was found that perceived enjoyment (PE) and usability were jointly related to the perceived usefulness (PU), although the association was relatively weak. Perceived enjoyment and learnability were jointly associated with perceived ease of use (PEOU), with the association accounting for 39% of the variation in PEOU. Usability was related to PE but learnability was not. Overall, the original TAM can be improved by the addition of learnability, PE and usability as they have a positive effect on TAM. In the final study, the task success rate was relatively high (i.e. 82.3% in session 1); however, an average participant took 3.6 times longer to complete the set of tasks than a competent user. Furthermore, task time, clicks and success rate improved only marginally in the second session (which was at the end of the semester). However, when compared with the analysis of the results from the standard usability questionnaires (subjective measures), participants stated that they were satisfied with the usability of the system, contradicting the objective measures (number of clicks, task time and success rate). Conclusions: Using subjective measures alone, in the form of standard usability questionnaires, to assess the usability of a complex system can conceal significant issues. Usability assessment should therefore be based on actual performance against a defined baseline and combined with forms of qualitative feedback such as free text responses. Evaluating the effect of usability on E-learning is complicated. The studies conducted in this thesis have provided valuable guidance on how to measure the usability of VLEs. Suggestions for future work on the usability of VLEs as well as appropriate recommendations are provided

Integrated mixing machine for sulfur concrete production

The production of sulfur concrete (SC) from its ingredient materials requires controlled heating and mixing conditions at a temperature level of 130°-150 °C. Although this process considered to be common and applicable at the industrial level, it is difficult at the laboratory/research level. This paper presents the design and manufacturing details of a relatively inexpensive laboratory machine for heating and mixing sulfur concrete. The different components of the machine are described in detail to help researchers to produce high-quality sulfur concrete. In this work, the quality of the machine is verified through experimental testing of the physical and mechanical properties of different prepared SC mixtures. Thus, the homogeneity and mixing efficiency required a certain level of workability, and the full controlling of temperature during the production process has been realized. The machine is proven to be efficient, safe, and durable. The comparative study on the physical and mechanical properties of the prepared SC relative to other SC of the same ingredients but heated and mixed through other small-scale machines, showed the superiority of the mixing machine in the production of high strength concrete

Ethnic and Gender Disparities in the Uptake of Transcatheter Aortic Valve Replacement in the United States

Introduction: Little is known about ethnic and gender disparities for transcatheter aortic valve replacement (TAVR) procedures in the United States. Methods: We queried the Nationwide Inpatient Sample (NIS) database (2011–2014) to identify patients who underwent TAVR. We described the temporal trends in the uptake of TAVR procedures among various ethnicities and genders. Results: Our analysis identified 39,253 records; 20,497 (52.2%) were men and 18,756 (47.8%) were women. Among all TAVRs, 87.2% were Caucasians, 3.9% were African Americans (AA), 3.7% were Hispanics, and 5.2% were of other ethnicities. We found a significant rise in the trend of TAVRs in all groups: in Caucasian men (coefficient = 0.946, p \u3c 0.001), Caucasian women (coefficient = 0.985, p \u3c 0.001), AA men (coefficient = 0.940, p \u3c 0.001), AA women (coefficient = 0.864, p \u3c 0.001), Hispanic men (coefficient = 0.812, p = 0.001), Hispanic women (coefficient = 0.845, p \u3c 0.001). Hence, the uptrend was most significant among Caucasian women, and relatively least significant among Hispanic men. Multivariate regression analysis was conducted to evaluate in-hospital mortality among different groups after adjusting for demographics and baseline characteristics. After multivariable regression for baseline characteristics overall, the in-hospital mortality per 100 TAVRs was highest among Hispanic men 5.5%, followed by Caucasian women 5.0%, Hispanic women 4.6%, AA women 3.7%, AA men 3.4%, and Caucasian men 3.38% (adjusted p value = 0.004). Conclusions: In this observational study, we demonstrated that there is evidence of ethnic and gender differences in the overall uptake and adjusted mortality of TAVRs in the United States

Surfactant-Free Peroxidase-Mediated Enzymatic Polymerization of a Biorenewable Butyrolactone Monomer via a Green Approach:Synthesis of Sustainable Biobased Latexes

A green surfactant-free one-pot horseradish peroxidase-mediated enzymatic polymerization is successfully applied to produce a sustainable and thermally stable biobased high average molar mass poly(α-methylene-γ-butyrolactone) (PMBL) at ambient conditions in water for the first time. The initiation step required only very low concentrations of hydrogen peroxide and 2,4-pentanedione water-soluble initiator to generate the keto-enoxy radicals responsible for forming the primary latex particles. The polymer nanoparticles can be seen as monodisperse, and the biobased latexes are colloidally stable and likely stabilized by the adsorption of 2,4-pentanedione moieties on the particle surfaces. Polymerizations in air produced a 98% yield of PMBL after only 3 h, highlighting the relevance of molecular oxygen. An array of characterization techniques such as dynamic light scattering (DLS), Fourier transform infrared (FTIR), 1H, 13C, and HSQC two-dimensional (2D) nuclear magnetic resonance (NMR), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and size-exclusion chromatography (SEC) are used to confirm the properties of the synthesized latexes. The PMBL exhibited high thermal stability, with only a 5% weight loss at 340 °C and a glass-transition temperature of 200 °C, which is double that of polymethyl methacrylate (PMMA). This research provides an interesting pathway for the synthesis of sustainable biobased latexes via enzymes in a green environment using just water at ambient conditions and the potential use of the polymer in high-temperature applications.</p

Surfactant-Free Peroxidase-Mediated Enzymatic Polymerization of a Biorenewable Butyrolactone Monomer via a Green Approach:Synthesis of Sustainable Biobased Latexes

A green surfactant-free one-pot horseradish peroxidase-mediated enzymatic polymerization is successfully applied to produce a sustainable and thermally stable biobased high average molar mass poly(α-methylene-γ-butyrolactone) (PMBL) at ambient conditions in water for the first time. The initiation step required only very low concentrations of hydrogen peroxide and 2,4-pentanedione water-soluble initiator to generate the keto-enoxy radicals responsible for forming the primary latex particles. The polymer nanoparticles can be seen as monodisperse, and the biobased latexes are colloidally stable and likely stabilized by the adsorption of 2,4-pentanedione moieties on the particle surfaces. Polymerizations in air produced a 98% yield of PMBL after only 3 h, highlighting the relevance of molecular oxygen. An array of characterization techniques such as dynamic light scattering (DLS), Fourier transform infrared (FTIR), 1H, 13C, and HSQC two-dimensional (2D) nuclear magnetic resonance (NMR), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and size-exclusion chromatography (SEC) are used to confirm the properties of the synthesized latexes. The PMBL exhibited high thermal stability, with only a 5% weight loss at 340 °C and a glass-transition temperature of 200 °C, which is double that of polymethyl methacrylate (PMMA). This research provides an interesting pathway for the synthesis of sustainable biobased latexes via enzymes in a green environment using just water at ambient conditions and the potential use of the polymer in high-temperature applications.</p

Surfactant-Free Peroxidase-Mediated Enzymatic Polymerization of a Biorenewable Butyrolactone Monomer via a Green Approach:Synthesis of Sustainable Biobased Latexes

A green surfactant-free one-pot horseradish peroxidase-mediated enzymatic polymerization is successfully applied to produce a sustainable and thermally stable biobased high average molar mass poly(α-methylene-γ-butyrolactone) (PMBL) at ambient conditions in water for the first time. The initiation step required only very low concentrations of hydrogen peroxide and 2,4-pentanedione water-soluble initiator to generate the keto-enoxy radicals responsible for forming the primary latex particles. The polymer nanoparticles can be seen as monodisperse, and the biobased latexes are colloidally stable and likely stabilized by the adsorption of 2,4-pentanedione moieties on the particle surfaces. Polymerizations in air produced a 98% yield of PMBL after only 3 h, highlighting the relevance of molecular oxygen. An array of characterization techniques such as dynamic light scattering (DLS), Fourier transform infrared (FTIR), 1H, 13C, and HSQC two-dimensional (2D) nuclear magnetic resonance (NMR), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and size-exclusion chromatography (SEC) are used to confirm the properties of the synthesized latexes. The PMBL exhibited high thermal stability, with only a 5% weight loss at 340 °C and a glass-transition temperature of 200 °C, which is double that of polymethyl methacrylate (PMMA). This research provides an interesting pathway for the synthesis of sustainable biobased latexes via enzymes in a green environment using just water at ambient conditions and the potential use of the polymer in high-temperature applications.</p

Case Report: Guillain–Barré Syndrome Associated With COVID-19

Guillain–Barré syndrome (GBS) is a potentially fatal, immune-mediated disease of the peripheral nervous system that is usually triggered by infection. Only a small number of cases of GBS associated with COVID-19 infection have been published. We report here five patients with GBS admitted to the Neurology, Psychiatry, and Neurosurgery Hospital, Assiut University/Egypt from July 1 to November 20, 2020. Three of the five patients were positive for SARS-CoV-2 following polymerase chain reaction (PCR) of nasopharyngeal swabs on day of admission and another one had a high level of IgM and IgG; all had bilateral ground-glass opacities with consolidation on CT chest scan (GGO) and lymphopenia. All patients presented with two or more of the following: fever, cough, malaise, vomiting, and diarrhea with variable duration. However, there were some peculiarities in the clinical presentation. First, there were only 3 to 14 days between the onset of COVID-19 symptoms and the first symptoms of GBS, which developed into flaccid areflexic quadriplegia with glove and stocking hypoesthesia. The second peculiarity was that three of the cases had cranial nerve involvement, suggesting that there may be a high incidence of cranial involvement in SARS-CoV-2-associated GBS. Other peculiarities occurred. Case 2 presented with a cerebellar hemorrhage before symptoms of COVID-19 and had a cardiac attack with elevated cardiac enzymes following onset of GBS symptoms. Case 5 was also unusual in that the onset began with bilateral facial palsy, which preceded the sensory and motor manifestations of GBS (descending course). Neurophysiological studies showed evidence of sensorimotor demyelinating polyradiculoneuropathy, suggesting acute inflammatory polyneuropathy (AIDP) in all patients. Three patients received plasmapheresis. All of them had either full recovery or partial recovery. Possible pathophysiological links between GBS and COVID-19 are discussed

Pre- and in-hospital delays in the use of thrombolytic therapy for patients with acute ischemic stroke in rural and urban Egypt

BackgroundReducing pre- and in-hospital delays plays an important role in increasing the rate of intravenous thrombolysis (IVT) in patients with acute ischemic stroke. In Egypt, the IVT rate has increased steadily but is still far away from an ideal rate.AimThe study aimed to investigate the factors associated with pre- and in-hospital delays of IVT among patients with acute ischemic stroke coming from urban and rural communities.MethodsThis prospective, multicenter, observational cohort study was conducted from January 2018 to January 2019. Patients with acute ischemic stroke, who did not receive IVT, were included in the study. Patients were recruited from three large university stroke centers in Egypt, Assiut (south of Egypt), Tanta (north of Egypt), both serving urban and rural patients, and the University Hospital in Cairo (capital city), only serving an urban community. All participants underwent the National Institutes of Health Stroke Scale and full neurological assessment, urgent laboratory investigations, and computed tomography or magnetic resonance imaging to confirm the stroke diagnosis. The patients were subjected to a structured questionnaire that was designed to determine the parameters and time metrics for the pre- and in-hospital delays among patients from rural and urban regions.ResultsA total of 618 patients were included in the study, of which 364 patients (58.9%) lived in rural regions and 254 (41.1%) in urban regions. General demographic characteristics were similar between both groups. Approximately 73.3% of patients who arrived within the therapeutic time window were urban patients. The time from symptom onset till hospital arrival (onset to door time, ODT) was significantly longer among rural patients (738 ± 690 min) than urban patients (360 ± 342 min). Delayed onset to alarm time (OAT), initial misdiagnosis, and presentation to non-stroke-ready hospitals were the most common causes of pre-hospital delay and were significantly higher in rural patients. For patients arriving within the time window, the most common causes of in-hospital delays were prolonged laboratory investigations and imaging duration.ConclusionThe limited availability of stroke-ready hospitals in rural Egypt leads to delays in stroke management, with subsequent treatment inequality of rural patients with acute stroke