Search

The use of natural gas as an alternative fuel in dual-fuel compression-ignition engines can lead to a substantial reduction in the majority of pollutant emissions compared to fossil fuels, while the thermal efficiency of the engine can be maintained at adequate levels. Its usage has increased widely in recent years, and significant efforts have been made to investigate the inherent physical and chemical processes that take place during this engine’s combustion, as well as the parameters that affect the operation of the engine and use natural gas as energy source. The scope of this study is to investigate the effect of EGR temperature (cold and hot) and rate (10% and 20%) on the performance characteristics and emissions of a dual-fuel compression-ignition engine operating at a specific engine operating point under dual-fuel (diesel–natural gas) conditions. For this reason, a phenomenological two-zone combustion model was developed. The results of the model were validated against the experimental data obtained from a single-cylinder direct-injection, turbocharged compression-ignition dual-fuel research engine operated under part-load conditions (IMEP = 0.52 Mpa and engine speed = 1500 rpm) and at various replacement percentages of diesel using methane (which was treated as a natural gas surrogate). The model results were in good agreement with the experimental results, revealing the ability of the model to be used in the aforementioned EGR analysis. The results of the study revealed that engine operation with 10% cold EGR does not significantly affect the engine performance characteristics, and combined with the addition of 80% gaseous fuel energy, can lead to a substantial reduction in NO and soot emissions, with a moderate increase in CO emissions. On the other hand, a significant finding of the present work is that engine operation with hot EGR under the investigated operating conditions, even though it had a beneficial effect on NO-specific emissions, led to a reduction in engine efficiency and may raise issues regarding the mechanical strength of the engine.

Given the widespread popularity of videogames, research attempted to assess their effects on cognitive and affective abilities, especially in children and adolescents. Despite numerous correlational studies, robust evidence on the causal relationship between videogames and cognition remains scarce, hindered by the absence of a comprehensive assessment tool for gaming skills across various genres. In a sample of 347 adolescents, this study aimed to develop and validate the Gaming Skill Questionnaire (GSQ) and assess the impact of gaming skills in six different genres (sport, first-person shooters, role-playing games, action-adventure, strategy, and puzzle games) on cognitive and affective abilities of adolescents. The GSQ exhibited strong reliability and validity, highlighting its potential as a valuable tool. Gaming skills positively affected executive function, memory, overall cognition, cognitive flexibility, and emotion recognition, except for empathy. Various game genres had different effects on cognitive and affective abilities, with verbal fluency influenced mainly by sports, executive functions by action, strategy, and puzzle, and emotion recognition positively impacted by action and puzzle but negatively by sports and strategy games. Both age and gaming skills influenced cognitive flexibility, with gaming having a greater effect. These intriguing genre-specific effects on cognitive and affective functioning postulate further research with GSQ's contribution.

Poor social skills in autism spectrum disorder (ASD) are associated with reduced independence in daily life. Current interventions for improving the social skills of individuals with ASD fail to represent the complexity of real-life social settings and situations. Virtual reality (VR) may facilitate social skills training in social environments and situations similar to those in real life; however, more research is needed to elucidate aspects such as the acceptability, usability, and user experience of VR systems in ASD. Twenty-five participants with ASD attended a neuropsychological evaluation and three sessions of VR social skills training, which incorporated five social scenarios with three difficulty levels. Participants reported high acceptability, system usability, and user experience. Significant correlations were observed between performance in social scenarios, self-reports, and executive functions. Working memory and planning ability were significant predictors of the functionality level in ASD and the VR system's perceived usability, respectively. Yet, performance in social scenarios was the best predictor of usability, acceptability, and functionality level. Planning ability substantially predicted performance in social scenarios, suggesting an implication in social skills. Immersive VR social skills training in individuals with ASD appears to be an appropriate service, but an errorless approach that is adaptive to the individual's needs should be preferred.

Background: Primary Sjogren's syndrome (SS) is an autoimmune disease with a strong predilection for lymphoma development, with earlier disease onset being postulated as an independent risk factor for this complication. Variations of the Leukocyte immunoglobulin-like receptor A3 (LILRA3) gene have been previously shown to increase susceptibility for both SS and non-Hodgkin B-cell lymphoma (B-NHL) in the general population. We aimed to investigate whether variations of the LILRA3 gene could predispose for lymphoma development in the context of SS., Methods: Study population, all of Greek origin, included 101 SS cases with a current or previous diagnosis of lymphoma (SS-lymphoma, SS-L) and 301 primary SS patients not complicated by lymphoma (SS-non-lymphoma, SS-nL). All SS patients fulfilled the 2016 SS American College of Rheumatology/European league against Rheumatism (ACR/EULAR) classification criteria. A total of 381 healthy controls (HC) of similar age/sex/race distribution were also included. On the basis of the age of SS onset and the presence or absence of adverse predictors for lymphoma development, SS patients were further stratified into younger (≤40 years) and older (>40 years) age of disease onset, as well as into high/medium and low risk groups. Polymerase chain reaction (PCR) was implemented for the detection of the following LILRA3 gene variants: homozygous non-deleted or functional wild type (+/+) heterozygous (+/-) and homozygous deleted (-/-). LILRA3 serum protein levels were quantitated by enzyme-linked immunosorbent assay (ELISA) in 85 individuals (29 SS-L, 35 SS-nL patients and 21 HC)., Results: While no statistically significant differences were detected in the overall frequency of LILRA3 gene variants between SS-L, SS-nL and HC groups, LILRA3 serum protein levels were increased in the SS-L group compared to HC (1.27 ± 1.34 vs. 0.38 ± 0.34 ng/mL, p -value: 0.004). After stratification according to the age of SS onset and history of lymphoma, as well as the presence or absence of adverse predictors for lymphoma development, the prevalence of the functional LILRA3 gene variant was found to be significantly increased in the young onset SS-L group compared to the HC of similar age and sex distribution (100% vs. 82.9%, p = 0.03), as well as in the high/medium risk SS compared to the low risk SS (91.3 vs. 78.3%, p = 0.0012). Of note, young onset SS-L and SS-nL groups displayed higher LILRA3 serum levels compared to their older counterparts ( p -values: 0.007 and 0.0005, respectively)., Conclusion: The functional LILRA3 gene variant increases susceptibility to SS-related lymphoma development in patients with a disease onset of <40 years old, implying that genetically determined deranged immune responses in younger SS individuals could underly their pronounced risk for lymphoma development.