Examining the moderating effect of individual-level cultural values on users’ acceptance of E-learning in developing countries: a structural equation modeling of an extended technology acceptance model

In this study, we examine the effects of individual-level culture on the adoption and acceptance of e-learning tools by students in Lebanon using a theoretical framework based on the Technology Acceptance Model (TAM). To overcome possible limitations of using TAM in developing countries, we extend TAM to include subjective norms (SN) and quality of work life constructs as additional constructs and a number of cultural variables as moderators. The four cultural dimensions of masculinity/femininity (MF), individualism/collectivism, power distance and uncertainty avoidance were measured at the individual level to enable them to be integrated into the extended TAM as moderators and a research model was developed based on previous literature. To test the hypothesised model, data were collected from 569 undergraduate and postgraduate students using e-learning tools in Lebanon via questionnaire. The collected data were analysed using the structural equation modelling technique in conjunction with multi-group analysis. As hypothesised, the results of the study revealed perceived usefulness (PU), perceived ease of use (PEOU), SN and quality of work life to be significant determinants of students’ behavioural intention (BI) towards e-learning. The empirical results also demonstrated that the relationship between SN and BI was particularly sensitive to differences in individual-cultural values, with significant moderating effects observed for all four of the cultural dimensions studied. Some moderating effects of culture were also found for both PU and PEOU, however, contrary to expectations the effect of quality of work life was not found to be moderated by MF as some previous authors have predicted. The implications of these results to both theory and practice are explored in the paper

Early Detection and Progression of Subclinical Atherosclerosis in Psoriasis (EDSAP): protocol for an observational, single-centre, prospective cohort study.

Introduction Life expectancy of patients with psoriasis is reduced by 4–5 years due to cardiovascular disease with an increased risk of myocardial infarction at an earlier age compared with the general population. This increased risk is independent of traditional cardiovascular risk factors and higher in moderate-to-severe forms of psoriasis. Inflammation may play a key role in the development of atherosclerosis in these patients. Methods and analysis A prospective cohort study, Early Detection and Progression of Subclinical Atherosclerosis in Psoriasis (EDSAP), was initiated in January 2020 to investigate the presence and progression of subclinical atherosclerosis in patients with psoriasis. 120 patients aged 30–65 years and eligible for biological treatment have been recruited at Hospital Ramón y Cajal in Madrid, Spain. Patients undergo a baseline visit, and 1-year follow-up visit after starting biological therapy. Each visit includes: assessment of cardiovascular risk factors, screening for subclinical atherosclerosis by two-dimensional/three-dimensional ultrasound of carotid and femoral arteries, cardiac CT of coronary arteries and blood sampling. All baseline visits were completed by December 2022, and the remaining follow-up visits will be concluded by the end of 2023. The EDSAP study aims to identify new molecular and imaging markers associated with the presence of atherosclerosis and its progression in a chronic inflammatory state such as psoriasis. This has the potential to: (1) help improve primary cardiovascular prevention strategies in these patients; (2) understand the effect of biological drugs on the cardiovascular system; and (3) serve as a model for understanding atherosclerosis in other chronic inflammatory diseases.569 K

Isolated rod dysfunction associated with a novel genotype of CNGB1

Purpose: To describe the clinical and electrophysiological features of an unusual retinopathy in a patient with a novel genotype of CNGB1, mutations in which are implicated in autosomal recessive retinitis pigmentosa (rod-cone dystrophy). Observations: A 61-year old asymptomatic woman was referred to the inherited retinal disorders clinic because of peripheral retinal pigmentary changes. She had normal visual acuity and color vision. Clinical examination and detailed imaging of the macula were normal, but there was atrophy of the outer retina in the periphery with sparse intra-retinal pigmentation. Electroretinography (ERG) revealed undetectable rod responses, with normal cone-mediated responses. The pattern ERG was normal. Genetic analysis identified two previously unreported variants in CNGB1: (c.2258T > A, p.[Leu753*] and c.807G > C, p.[Gln269His]), shown to be in trans. Conclusions and importance: This report describes a functionally cone-isolated retina in an adult, apparently hemizygous for a novel missense mutation in CNGB1, a novel phenotype for this gene. The p.[Gln269His] allele is the first missense change, within the glutamic acid-rich protein (GARP) domain of CNGB1, to be associated with retinal disease in humans

CERKL-associated retinal dystrophy: Genetics, Phenotype and Natural History

PURPOSE: To analyze the clinical characteristics, natural history, and genetics of CERKL-associated retinal dystrophy in the largest series to date. DESIGN: Multicenter retrospective cohort study. SUBJECTS: 47 patients (37 families) with likely disease-causing CERKL variants METHODS: Review of clinical notes, ophthalmic images, and molecular diagnosis from two international centres. MAIN OUTCOME MEASURES: Visual function, retinal imaging and characteristics were evaluated and correlated. RESULTS: The mean age at the first visit was 29.6 + 13.9 years and the mean follow-up time was 9.1 + 7.4 years. The most frequent initial symptom was central vision loss (40%) and the most common retinal feature was well-demarcated areas of macular atrophy (57%). Seventy percent of the participants had double-null genotypes and 64% had electrophysiological assessment. Amongst the latter, 53% showed similar severity of rod and cone dysfunction, 27% revealed a rod-cone, 10% a cone-rod, and 10% a macular dystrophy dysfunction pattern. Patients without double-null genotypes tended to have fewer pigment deposits and included a higher proportion of older patients with a relatively mild electrophysiological phenotype. Longitudinal analysis showed that over half of the cohort lost 15 ETDRS letters or more in at least one eye during the first 5 years of follow up. CONCLUSIONS: The phenotype of CERKL-retinal dystrophy is broad, encompassing isolated macular disease to severe retina-wide involvement, with a range of functional phenotypes, generally not fitting in the rod-cone/cone-rod dichotomy. Disease onset is often earlier, with more severe retinal degenerative changes and photoreceptor dysfunction, in nullizygous cases

Ceramide synthase TLCD3B is a novel gene associated with human recessive retinal dystrophy

PURPOSE: Previous studies suggest that ceramide is a proapoptotic lipid as high levels of ceramides can lead to apoptosis of neuronal cells, including photoreceptors. However, no pathogenic variant in ceramide synthases has been identified in human patients and knockout of various ceramide synthases in mice has not led to photoreceptor degeneration. METHODS: Exome sequencing was used to identify candidate disease genes in patients with vision loss as confirmed by standard evaluation methods, including electroretinography (ERG) and optical coherence tomography. The vision loss phenotype in mice was evaluated by ERG and histological analyses. RESULTS: Here we have identified four patients with cone-rod dystrophy or maculopathy from three families carrying pathogenic variants in TLCD3B. Consistent with the phenotype observed in patients, the Tlcd3bKO/KO mice exhibited a significant reduction of the cone photoreceptor light responses, thinning of the outer nuclear layer, and loss of cone photoreceptors across the retina. CONCLUSION: Our results provide a link between loss-of-function variants in a ceramide synthase gene and human retinal dystrophy. Establishment of the Tlcd3b knockout murine model, an in vivo photoreceptor cell degeneration model due to loss of a ceramide synthase, will provide a unique opportunity in probing the role of ceramide in survival and function of photoreceptor cells

Asymptotic Expansions for Stationary Distributions of Perturbed Semi-Markov Processes

New algorithms for computing of asymptotic expansions for stationary distributions of nonlinearly perturbed semi-Markov processes are presented. The algorithms are based on special techniques of sequential phase space reduction, which can be applied to processes with asymptotically coupled and uncoupled finite phase spaces.Comment: 83 page