"Direct" grafting of linear macromolecular "wedges" to the edge of pristine graphite to prepare edge-functionalized graphene-based polymer composites

The edges of pristine graphite were covalently grafted with para-poly(ether-ketone) (pPEK) in a mildly acidic polyphosphoric acid (PPA)/phosphorus pentoxide (P(2)O(5)) medium. The resulting pPEK grafted graphite (pPEK-g-graphite) showed that the pristine graphite had been exfoliated into a few layers of graphene platelets (graphene-like sheets), which were uniformly dispersed into a pPEK matrix. As a result, the tensile properties of pPEK-g-graphite films were greatly improved compared to those of controlled pPEK films. The origins of these enhanced mechanical properties were deduced from scanning electron microscope (SEM) images of fracture surfaces. Upon tracing wide-angle X-ray scattering (WAXS) patterns of the film under strain, the graphene-like sheets were further exfoliated by an applied shear force, suggesting that a toughening mechanism for the pPEK-g-graphite film occurred. This approach envisions that the "direct'' edge grafting of pristine graphite without pre-treatments such as corrosive oxidation and/or destructive sonication is a simple and efficient method to prepare graphene-based polymer composites with enhanced mechanical properties.close161

Comparative analysis of multiple classification models to improve PM10 prediction performance

With the increasing requirement of high accuracy for particulate matter prediction, various attempts have been made to improve prediction accuracy by applying machine learning algorithms. However, the characteristics of particulate matter and the problem of the occurrence rate by concentration make it difficult to train prediction models, resulting in poor prediction. In order to solve this problem, in this paper, we proposed multiple classification models for predicting particulate matter concentrations required for prediction by dividing them into AQI-based classes. We designed multiple classification models using logistic regression, decision tree, SVM and ensemble among the various machine learning algorithms. The comparison results of the performance of the four classification models through error matrices confirmed the f-score of 0.82 or higher for all the models other than the logistic regression model

The role of social support and social networks in smoking behavior among middle and older aged people in rural areas of South Korea: A cross-sectional study

<p>Abstract</p> <p>Background</p> <p>Although the number of studies on anti-smoking interventions has increased, studies focused on identifying social contextual factors in rural areas are scarce. The purpose of this study was to explore the role of social support and social networks in smoking behavior among middle and older aged people living in rural areas of South Korea.</p> <p>Methods</p> <p>The study employed a cross-sectional design. Participants included 1,057 adults, with a mean age of 60.7 years, residing in rural areas. Information on participants' tobacco use, stress, social support, and social networks was collected using structured questionnaires. The chi-square test, the t-test, ANOVA, and logistic regression were used for data analysis.</p> <p>Results</p> <p>The overall smoking prevalence in the study was 17.4% (men, 38.8%; women, 5.1%). Overall, stress was high among women, and social support was high among men. Smokers had high levels of social support (t = -2.90, p = .0038) and social networks (t = -2.22, p = .0271), as compared to non- and former smokers. Those in the high social support group were likely to be smokers (AOR = 2.21, 95% CI 1.15-4.26). Women with moderate social ties were less likely to smoke (AOR = 0.18, 95% CI 0.05-0.61).</p> <p>Conclusion</p> <p>There was a protective role of a moderate social network level among women, and a high level of social support was associated with smoking behaviors in rural areas. Findings suggest the need for a comprehensive understanding of the functions and characteristics of social contextual factors including social support and social networks in order to conduct more effective anti-smoking interventions in rural areas.</p

Inhibition of ATR Increases the Sensitivity to WEE1 Inhibitor in Biliary Tract Cancer

Purpose Currently, the DNA damage response (DDR) pathway represents a key target for new cancer drug development. Advanced biliary tract cancer (BTC) has a poor prognosis because of the lack of efficacious treatment options. Although DNA repair pathway alterations have been reported in many patients with BTC, little is known regarding the effects of DDR-targeted agents against BTC. Materials and Methods In this study, nine BTC cell lines were exposed to the WEE1 inhibitor (AZD1775). In vitro, MTT assay, colony-forming assay, cell cycle analysis, phospho-histone H3 staining assay, Transwell migration assay, and western blot were performed. Then, to enhance the antitumor effect of AZD1775, the combination treatment of WEE1 inhibitor and ataxia telangiectasia mutated and Rad3 related (ATR) inhibitor (AZD6738) was conducted using MTT assay and comet assay. Finally, HuCCT-1 and SNU2670 xenograft models were established to confirm the anti-tumor effect of AZD1775 alone. Furthermore, the combination treatment was also evaluated in SNU2670 xenograft models. Results AZD1775 blocked the phosphorylation of CDC2 and CDC25C in all cell lines, but significantly increased apoptosis and S phase arrest in sensitive cells. However, increased p-ATR and phosphorylated ataxia telangiectasia mutated levels were observed in less sensitive cells. In addition, in vitro and in vivo data illustrated that AZD1775 combined with AZD6738 exerted more potent anti-tumor effects than either drug alone. Although WEE1 inhibition has promising anti-tumor effects in some BTC cells, the addition of ATR inhibitors could enhance its efficacy. Conclusion Taken together, this study supports further clinical development of DDR-targeted strategies as monotherapy or combination regimens for BTC.

Acute perimyocarditis mimicking acute myocardial infarction in a 12-year-old boy with Duchenne muscular dystrophy

Differential diagnosis of chest pain in the pediatric population is important but can be challenging. A 12-year-old boy with Duchenne muscular dystrophy presented with chest pain, cardiac enzyme elevation, and convex ST elevations in the inferior leads with reciprocal ST depression in the anterior leads on electrocardiogram. Echocardiography on admission revealed normal left ventricular function. Suspecting acute myocardial infarction, we performed invasive coronary angiography, which revealed normal coronary arteries. A follow-up electrocardiogram showed an acute pericarditis pattern with concave ST elevations in most leads and PR depression, and follow-up echocardiography revealed global left ventricular dysfunction, suggestive of acute perimyocarditis. Ibuprofen was administered for acute pericarditis, and a continuous milrinone infusion was commenced for myocardial dysfunction. The chest pain improved by the next day, and the ST segment elevations normalized on day 4. Echocardiography on day 9 revealed improved left ventricular function. The patient was discharged on day 11, and he is doing well without chest pain through 12 months of follow-up. The last electrocardiogram showed normal sinus rhythm without ST change. Differential diagnosis of acute myocardial infarction and acute perimyocarditis is important for proper treatment strategies and the different prognoses of these two conditions

Cognitive Enhancing and Neuroprotective Effect of the Embryo of the Nelumbo nucifera

The aim of the present study was to evaluate the effect of ENS on cognitive impairment induced by scopolamine and its potential neuroprotective effect against glutamate-induced cytotoxicity in HT22 cell and to investigate the underlying mechanisms. ENS (3, 10, 30, and 100 mg/kg), scopolamine (1 mg/kg), and donepezil (1 mg/kg) were administered to mice during a test period. Scopolamine impaired memory and learning in a water maze test and a passive avoidance test. The neuroprotective effect of ENS (10 and 100 μg/mL) was investigated on glutamate-induced cell death in HT22 cells by MTT assay. We investigated acetylcholinesterase inhibition in hippocampus and antioxidant activity, ROS levels, and Ca2+ influx in HT22 cells to elucidate the potential mechanisms of ENS. We found that ENS significantly ameliorated scopolamine-induced memory impairment and inhibited AChE activity in hippocampus. In vitro, ENS showed potent neuroprotective effects against glutamate-induced neurotoxicity in the HT22 cell. In addition, ENS induced a decrease in ROS production and intercellular Ca2+ accumulation and showed DPPH radical and H2O2 scavenging activity. In conclusion, ENS showed both a memory improving effect and a neuroprotective effect. Our results indicate that ENS may be of use in the treatment and prevention of neurodegenerative disorders

The risk of newly diagnosed cancer in patients with rheumatoid arthritis by TNF inhibitor use: a nationwide cohort study

Background : Tumor necrosis factor (TNF) inhibitors use in patients with rheumatoid arthritis (RA) has raised safety concerns about cancer risk, but study results remain controversial. This largest nationwide study to date compared cancer risk in TNF inhibitor users to non-biologic disease-modifying anti-rheumatic drug (nbDMARD) users in Korean patients with RA. Methods : Data on all the eligible patients diagnosed with RA between 2005 and 2016 were retrieved from the Korean National Health Information Database. The one-to-one matched patients consisted of the matched cohort. The risks for developing all-type and site-specific cancers were estimated using incidence and incidence rate (IR) per 1000 person-years. Adjusted hazard ratio (HR) and 95% confidence interval (CI) were estimated using a Cox regression model. Results : Of the 22,851 patients in the before matching cohort, 4592 patients were included in the matched cohort. Treatment with TNF inhibitors was consistently associated with a lower risk of cancer than in the nbDMARD cohort (IR per 1000 person-years, 6.5 vs. 15.6; adjusted HR, 0.379; 95% CI, 0.255–0.563). The adjusted HR (95% CI) was significantly lower in the TNF inhibitor cohort than the nbDMARD cohort for gastrointestinal cancer (0.432; 0.235–0.797), breast cancer (0.146; 0.045–0.474), and genitourinary cancer (0.220; 0.059–0.820). Conclusions : The use of TNF inhibitors was not associated with an increased risk of cancer development, and rather associated with a lower cancer incidence in Korean patients with RA. Cautious interpretation is needed not to oversimplify the study results as cancer-protective effects of TNF inhibitors. A further study linking claims and clinical data is needed to confirm our results.This research was supported by a grant of the Korea Health Technology R&D Project through the Korea Health Industry Development Institute (KHIDI), funded by the Ministry of Health & Welfare, Republic of Korea (grant number: HC17C0069