163559 research outputs found
Sort by
Pathological implications of Porphyromonas gingivalis in Alzheimers disease and therapeutic potential of gingipain inhibitors
No full textPorphyromonas gingivalis is a key pathogen in periodontitis associated with Alzheimers disease (AD) through multiple mechanisms. Recent findings regarding the existence of its DNA and proteins in ADs brain tissues reveal its ability to breach the blood–brain barrier (BBB). This study overviews the potential mechanisms of action of P. gingivalis , including its direct migration to the brain via BBB disruption and indirect effects mediated by outer membrane vesicles carrying toxic components, such as gingipains, lipopolysaccharides, and fimbriae. The implications of P. gingivalis-induced neuroinflammation, amyloid-β aggregation, and tubulinassociated unit protein modification in AD pathology, together with emerging therapeutic strategies targeting gingipain, were also explored.N
Comparison of bioprosthetic valves in primary isolated aortic valve replacement: a nationwide study†
No full textOBJECTIVES This study aimed to comprehensively compare the early and long-term clinical outcomes of bovine pericardial valve (BOV) and porcine valve (POV), specifically during the primary isolated aortic valve replacement (AVR), using data from the Korean National Health Insurance Service (NHIS) database.METHODS Using the Korean NHIS claimed data, all adult patients (age >= 19) who underwent primary isolated AVR using bioprosthetic valve from 2003 to 2019 were identified and propensity-score matching (PSM) analysis was performed.RESULTS Overall, 5470 patients with BOV (n = 3947, group B) or POV (n = 1,523, group P) were enrolled, of whom 814 pairs were matched in a 1:1 ratio using PSM analysis. Early postoperative mortality and morbidities were comparable between the groups before and after PSM, considering inter-hospital clustering. The cumulative incidence of all-cause mortality was higher in group P than in group B in the total cohort (group B 5.3%/patient-years vs group P 6.4%/patient-years, adjusted hazard ratio: 1.20, P = 0.002), whereas those differences in all-cause mortality disappeared in PSM analysis (P = 0.24). The cumulative incidences of late stroke, reoperation and infective endocarditis were not significantly different between the groups in PSM populations.CONCLUSIONS In Korean national database cohort patients with primary isolated AVR, there was no significant difference in the early- and long-term clinical outcomes between BOV and POV. In surgical aortic valve replacement (AVR), bioprosthetic valves are core implants, especially those used in elderly patients because they do not require lifelong anticoagulation and have sufficient durability [1-3].N
Associations of metabolic variabilities and cardiovascular outcomes according to estimated glomerular filtration rate in chronic kidney disease: a nationwide observational cohort study
No full textBackground: The impact of baseline estimated glomerular filtration rate (eGFR) on the risk of adverse outcomes according to metabolic parameter variabilities in chronic kidney disease has rarely been investigated. Methods: We conducted a retrospective nationwide cohort study using the National Health Insurance System data in Korea from 2007 to 2013 to identify individuals with three or more health screenings. The metabolic components variability was defined as intraindividual variability between measurements using the variability independent of the mean. The metabolic variability score was defined as the total number of high-variability metabolic components. Multivariable-adjusted Cox regression analysis was conducted to evaluate the risks of all-cause mortality, myocardial infarction, and ischemic stroke. Results: During a mean follow-up of 6.0 +/- 0.7 years, 223,531 deaths, 107,140 myocardial infarctions, and 116,182 ischemic strokes were identified in 9,971,562 patients. Low eGFR categories and higher metabolic variability scores were associated with a higher risk of adverse outcomes. The degree of association between metabolic variability and adverse outcomes was significantly larger in those with low eGFR categories than in those with preserved eGFR (p for interaction < 0.001). Representatively, those with high metabolic variability in the eGFR of <15 mL/min/1.73 m(2) group showed a prominently higher risk for all-cause mortality (adjusted hazard ratio [aHR], 5.28; 95% confidence interval [CI], 4.02-6.94) when the degree was compared to the findings in those with preserved (eGFR of >= 60 mL/min/1.73 m(2)) kidney function (aHR, 2.55; 95% CI, 2.41-2.69). Conclusion: The degree of adverse association between metabolic variability and poor prognosis is accentuated in patients with impaired kidney function.Y
A Bias Correction Method for AMSR2 Brightness Temperature Over Global Ocean and Its Impact on Ocean Surface Roughness Estimation
No full textIt has been reported that brightness temperatures (TBs) measured by Advanced Microwave Scanning Radiometer 2 (AMSR2) show discrepancies compared to those measured by other microwave (MW) radiometers. To address this issue, the interconversion coefficients between AMSR2 and AMSR-E were developed by Japan Aerospace Exploration Agency (JAXA) and have been applied in many studies. Despite this, this study shows that the single differences (SDs) remain in AMSR2 TBs even after applying the JAXA-provided coefficients. In this study, a set of bias correction coefficients for AMSR2 is fit for each 20(degrees)x20(degrees) grid box to eliminate these residual SDs over the calm global ocean. The root-mean-square differences (RMSDs) between the observed and simulated TBs are significantly reduced after applying the bias correction scheme developed in this study by at least 64.40% at 7.3-GHz v-pol and at most 86.42% at 10.65-GHz v-pol during descending orbits. The estimation of two-scale roughness after the bias correction agrees with the physically expected values, demonstrating that the bias correction of AMSR2 TBs from this study can improve the accuracy of oceanic parameter estimation.Y
The Estimation of Quarterly Potential GDP using Industry-level Quarterly Total Factor Productivity Estimates in Korea
No full textThis study estimates the quarterly potential GDP of Korea from 2012 Q1 to 2023 Q4 by using industry-level total factor productivity (TFP) data. By referring to the EU KLEMS classification and Fernald (2014), this study constructs a quarterly capital stock and TFP database for 17 industries and adjusts their labor and capital inputs with proxy variables, namely, the labor intensity index and the capacity utilization index. This study compares models with and without input adjustments and reveals a post-pandemic decline in labor productivity and a slow capital input recovery. The adjusted model shows significantly high TFP contributions, which highlights the importance of input adjustments for accurate TFP analyses and potential GDP estimates. The GDP gap is negative during the pandemic period. Although the GDP gap became positive in 2023 Q4, the subsequent decline in the quarterly potential GDP growth indicates economic stagnation in Korea
Confined anionic electrons and their effect on physical properties of Ca2N bilayers with different stacking configurations
No full textCa2N is a unique two-dimensional material due to its confined anionic electrons. Unlike three-dimensional materials, the framework of Ca2N effectively confines the anionic electrons, leading to interesting physical and chemical properties. To study the electrical and optical properties of Ca2N bilayers with various stacking configurations, we used density functional theory calculations. This approach allowed us to investigate the behavior of anionic electrons located at the interlayer interface and at the surface. Using maximally localized Wannier functions to extract tight-binding parameters for each stacking configuration, we determined Hofstadter's butterfly patterns for each structure, which provide a valuable insight into the influence of an external magnetic field on the electronic band structure. This work paves the way for further exploration of experimentally feasible configurations and their potential applications.N
A unifying principle for global greenness patterns and trends
No full textVegetation cover regulates the exchanges of energy, water and carbon between land and atmosphere. Remotely-sensed fractional absorbed photosynthetically active radiation (fAPAR), a land-surface greenness measure, depends on carbon allocation to foliage while also controlling photon flux for photosynthesis. Here we use an equation with just two globally fitted parameters to describe annual maximum fAPAR as the smaller of a water-limited value transpiring a constant fraction of annual precipitation, and an energy-limited value maximizing annual plant growth. This minimalist description reproduces global greenness patterns and temporal trends in remote-sensing data, comparable to the best-performing dynamic global vegetation models. Widely observed greening is attributed principally to the influence of rising carbon dioxide on the light- and water-use efficiencies of photosynthesis; limited browning regions are attributed to drying. This research provides one key component of ecosystem function as a step towards more robust foundations for new-generation land ecosystem models.N
Remote Real-Time Training for Sustainable Cleft Operation in Rural Region of West Africa: Effective Webinar in the COVID-19 Pandemic
No full textIntroduction:The surgical requirement for cleft lip and palate repair remains unmet in many developing areas of the world, including remote regions of Ghana. This article reviews the utilization of Internet education and online consultation for cleft lip and palate surgical training in Sunyani Regional Hospital (SRH), Ghana.Methods:The cleft lip and palate treatment was promoted to patients in remote areas of Sunyani, Ghana region, through a charitable outreach program. These basic designs and settings were managed by local participants such as doctors, residents, nurses, and staff in SRH, Ghana.Results:From November 2014 to December 2020, the authors collaborated in surgical treatment for 84 cases that were diagnosed with unilateral cleft lip, bilateral cleft lip, hard and soft palate cleft, and microstomia. The type of surgery has varied and has included cheiloplasty, palatoplasty, and others. The average scores of esthetic outcome evaluation were nasal form=2.4, symmetry of the nose=2.9, and vermillion border=2.9. Through the program, the surgeons and residents became significantly more proficient at cleft lip and palate surgery. The seminar topics have covered essential and sustainable topics based on SRH's current needs and showed the effectiveness in the current coronavirus disease-19 pandemic situation.Conclusions:The shortage of orofacial cleft surgeons working in rural areas like Sunyani, Ghana, remains an obstacle that poses a challenge to any effort to improve health care quality in these rural communities. Sustainable remote education is essential for the training of local cleft surgeons to fill this local need; our collaborative and charitable program could be a recommended education design for cleft surgeons and institutes for their sustainable education.N
Enhancing Construction Managers' Risk Perception and Lowering Risk Tolerance toward Unsafe Behaviors Through Experiential Safety Training
No full textThe training effect can be enhanced when trainees/learners interact with real-world environments and construct personal knowledge from those direct experiences. Leveraging such experiential learning strategies for occupational training has been widely discussed due to its effectiveness. The construction industry has also been focusing on experiential safety training to address the limitations in conventional classroom-based training, such as passive learning and limited interaction with actual physical hazards. Recently, government organizations and construction companies have started to operate safety training facilities, where trainees can physically experience the negative consequences of unsafe behaviors (without actual injuries). Although the effect of experiential safety training at those facilities has been anecdotally noted, no study has empirically investigated its effectiveness in enhancing trainees' risk perception toward unsafe behaviors. To this end, this study examined the effectiveness of experiential safety training in enhancing construction managers' risk perception toward workers' unsafe behaviors and their intention to stop workers from working in dangerous situations. The results, based on answers to survey questions showing scene images of unsafe behavior related to the risk of a fall, show that construction managers who participated in experiential safety training perceived a higher risk regarding workers' unsafe behaviors in less obviously risky situations, and exhibited a stronger intention to immediately stop workers from working in subtly unsafe conditions. This study contributes empirical evidence about the effectiveness of experiential safety training at safety training centers, thereby promoting the wide adoption of experiential safety training and advancing safety engineering and management strategies in the construction industry.N
Videoconferencing Delivery of the Seoul Premarital Education Program During COVID-19: A Quasi-experimental Study Using Inverse Probability of Treatment Weighting
No full textThis study examined whether the Seoul Premarital Education Program (S-PEP) was effective when it was delivered via videoconferencing (VC) during the early COVID-19 period. S-PEP is a city-wide educational program designed to prevent marital distress by enhancing premarital readiness and relationship quality for couples. Because a randomized controlled trial was not realistic due to the pandemic, we recruited an intervention group and a no-intervention comparison group independently, who completed both the pre- and posttests. We then employed inverse probability of treatment weighting to derive two comparable groups. The weighted samples of 291 women and 228 men were analyzed separately using linear mixed models. The results showed that S-PEP via VC was effective in increasing levels of marital readiness for both women and men and in enhancing relationship confidence and satisfaction for women. Our findings suggest that VC can be a promising delivery strategy for curriculum-based group interventions for couples.Y