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This study investigates how the course format change caused by covid-19 pandemic affected learning behaviors and performance of college students enrolled in a large introductory history course. Clickstream log files capturing how students were interacting with online learning contents were analyzed to identify the learning behaviors of students before and after the mid-semester course format change. The non-parametric regression model was developed to examine the relationship between learning performance of students and course format change. Although the frequency of accessing learning resources decreased during the first three weeks after the course format change, it had a relatively small effect on the learning performance of students. The quantile regression model indicates the mid-semester course format change is associated with about 3.3% decrease in the learning performance of students. These results suggest that students were quite resilient and their learning during the pandemic was not as bad as we feared.

The generation of antigen-specific cytotoxic T lymphocyte (CTL) responses is required for successful cancer vaccine therapy. In this regard, ligands of Toll-like receptors (TLRs) have been suggested to activate adaptive immune responses by modulating the function of antigen-presenting cells (APCs). Despite their therapeutic potential, the development of TLR ligands for immunotherapy is often hampered due to rapid systemic toxicity. Regarding the safety concerns of currently available TLR ligands, finding a new TLR agonist with potent efficacy and safety is needed. A unique structural domain (UNE-C1) was identified as a novel TLR2/6 in the catalytic region of human cysteinyl-tRNA synthetase 1 (CARS1) using comprehensive approaches, including RNA sequencing, the human embryonic kidney (HEK)-TLR Blue system, pull-down, and ELISA. The potency of its immunoadjuvant properties was analyzed by assessing antigen-specific antibody and CTL responses. In addition, the efficacy of tumor growth inhibition and the presence of the tumor-infiltrating leukocytes were evaluated using E.G7-OVA and TC-1 mouse models. The combined effect of UNE-C1 with an immune checkpoint inhibitor, anti-CTLA-4 antibody, was also evaluated in vivo. The safety of UNE-C1 immunization was determined by monitoring splenomegaly and cytokine production in the blood. Here, we report that CARS1 can be secreted from cancer cells to activate immune responses via specific interactions with TLR2/6 of APCs. A unique domain (UNE-C1) inserted into the catalytic region of CARS1 was determined to activate dendritic cells, leading to the stimulation of robust humoral and cellular immune responses in vivo. UNE-C1 also showed synergistic efficacy with cancer antigens and checkpoint inhibitors against different cancer models in vivo. Further, the safety assessment of UNE-C1 showed lower systemic cytokine levels than other known TLR agonists. We identified the endogenous TLR2/6 activating domain from human cysteinyl-tRNA synthetase CARS1. This novel TLR2/6 ligand showed potent immune-stimulating activity with little toxicity. Thus, the UNE-C1 domain can be developed as an effective immunoadjuvant with checkpoint inhibitors or cancer antigens to boost antitumor immunity.

In low-dose cone beam computed tomography (CT), the insufficient number of photons inevitably results in noise, which reduces the accuracy of disease diagnosis. One approach to improving the image quality of CT images acquired using a low-dose protocol involves the utilization of a reconstruction algorithm that efficiently reduces noise. In this study, we modeled the Feldkamp–Davis–Kress (FDK) algorithm using various filters and projection angles and applied it to the reconstruction process using CT simulation. To quantitatively evaluate the quality of the reconstruction images, we measured the coefficient of variation (COV), and signal-to-noise ratio (SNR) in the air, brain, and bone regions to evaluate the noise level. Furthermore, we calculated root mean square error (RMSE), universal image quality index (UQI), and blind/referenceless image spatial quality evaluator (BRISQUE) as similarity and no-reference evaluation. The Hann filter of the FDK algorithm showed superior performance in terms of COV, SNR, RMSE, and UQI compared to the other filters. In addition, when analyzing the COV and SNR results, we observed that image quality increased significantly at projection angles smaller than approximately 2.8°. Moreover, based on BRISQUE results, we confirm that the Shepp–Logan filter exhibited the most superior performance. In conclusion, we believe that the application of the Hann filter in the FDK reconstruction process offers significant advantages in improving the image quality acquired under a low-dose protocol, and we expect that our study will be a preliminary study of no-reference evaluation of CT reconstruction images. [ABSTRACT FROM AUTHOR]

Noise in computed tomography (CT) is inevitably generated, which lowers the accuracy of disease diagnosis. The non-local means approach, a software technique for reducing noise, is widely used in medical imaging. In this study, we propose a noise reduction algorithm based on fast non-local means (FNLMs) and apply it to CT images of a phantom created using 3D printing technology. The self-produced phantom was manufactured using filaments with similar density to human brain tissues. To quantitatively evaluate image quality, the contrast-to-noise ratio (CNR), coefficient of variation (COV), and normalized noise power spectrum (NNPS) were calculated. The results demonstrate that the optimized smoothing factors of FNLMs are 0.08, 0.16, 0.22, 0.25, and 0.32 at 0.001, 0.005, 0.01, 0.05, and 0.1 of noise intensities, respectively. In addition, we compared the optimized FNLMs with noisy, local filters and total variation algorithms. As a result, FNLMs showed superior performance compared to various denoising techniques. Particularly, comparing the optimized FNLMs to the noisy images, the CNR improved by 6.53 to 16.34 times, COV improved by 6.55 to 18.28 times, and the NNPS improved by 10−2 mm2 on average. In conclusion, our approach shows significant potential in enhancing CT image quality with anthropomorphic phantoms, thus addressing the noise issue and improving diagnostic accuracy. [ABSTRACT FROM AUTHOR]

Gamification, the use of game design elements in non-gaming context, has been introduced to education as a novel teaching and learning approach to engage learners. Current literature has focused on finding ways to afford the playfulness and gamefulness of gamification. This paper has studied college students' perceptions of pleasure in learning to explore the underlying aspects of enjoyment in their learning experiences. Based upon the playful experiences (PLEX) design framework (Arrasvuori et al., 2011), we distributed an online survey to 235 college students and used Principal Component Analysis (PCA) to find four underlying aspects of pleasurable learning experiences among the participants: instruction (Cronbach's a = 0.84), instructors' teaching styles (Cronbach's a = 0.87), learning effectiveness (Cronbach's a = 0.71), and collaboration (Cronbach's a = 0.71). This scale can be used for gamification designers to identify the key game design elements for their target learners. We have also examined the effects of gender, majors, computer skills, and gaming habits on participants' preferences for pleasure in learning. Majors resulted in statistically significant differences among the participants' attitudes towards collaboration (F(6, 212) = 5.84, p < 0.001, Eta-square = 0.14). The implications of the findings are also discussed in the paper.

Cinematic rendering (CR) is a new 3D post-processing technology widely used to produce bone computed tomography (CT) images. This study aimed to evaluate the performance quality of CR in bone CT images using blind quality and noise level evaluations. Bone CT images of the face, shoulder, lumbar spine, and wrist were acquired. Volume rendering (VR), which is widely used in the field of diagnostic medical imaging, was additionally set along with CR. A no-reference-based blind/referenceless image spatial quality evaluator (BRISQUE) and coefficient of variation (COV) were used to evaluate the overall quality of the acquired images. The average BRISQUE values derived from the four areas were 39.87 and 46.44 in CR and VR, respectively. The difference between the two values was approximately 1.16, and the difference between the resulting values increased, particularly in the bone CT image, where metal artifacts were observed. In addition, we confirmed that the COV value improved by 2.20 times on average when using CR compared to VR. This study proved that CR is useful in reconstructing bone CT 3D images and that various applications in the diagnostic medical field will be possible. [ABSTRACT FROM AUTHOR]

This study investigated health-related quality of life and identified factors affecting it among people with the HIV in South Korea. A total of 243 people living with HIV participated in this cross-sectional survey. Data were collected from five hospitals between November 2021 and August 2022 using structured online questionnaires. Data were analyzed using descriptive statistics, Mann-Whitney U test, Kruskal-Wallis test, Spearman's rho analysis, and Tobit regression analysis because a significant ceiling effect was observed for the dependent variable. The mean score for the health-related quality of life was 75.74 ± 16.48. The significant factors that positively influence the health-related quality of life were "employment" (B = 4.57, p =.035), "not participating in the self-help group" (B = 6.10, p =.004), "higher self-efficacy for managing symptoms" (B = 1.32, p =.036), "higher self-efficacy for getting support/help" (B = 0.95, p =.035), and "higher self-efficacy for managing fatigue" (B = 2.80, p <.001) in the Tobit regression analysis. The results suggest that interventions to increase self-efficacy should involve developing programs and policies for people living with HIV. There is a need for efforts to provide healthcare services linked to employment support, as well as to establish a social environment in which they can work without stigma. Further, self-help groups could be utilized as intervention channels. [ABSTRACT FROM AUTHOR]