161 research outputs found

    Therapeutic effects of phlorotannins in the treatment of neurodegenerative disorders

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    Phlorotannins are natural polyphenolic compounds produced by brown marine algae and are currently found in nutritional supplements. Although they are known to cross the blood–brain barrier, their neuropharmacological actions remain unclear. Here we review the potential therapeutic benefits of phlorotannins in the treatment of neurodegenerative diseases. In mouse models of Alzheimer’s disease, ethanol intoxication and fear stress, the phlorotannin monomer phloroglucinol and the compounds eckol, dieckol and phlorofucofuroeckol A have been shown to improve cognitive function. In a mouse model of Parkinson’s disease, phloroglucinol treatment led to improved motor performance. Additional neurological benefits associated with phlorotannin intake have been demonstrated in stroke, sleep disorders, and pain response. These effects may stem from the inhibition of disease-inducing plaque synthesis and aggregation, suppression of microglial activation, modulation of pro-inflammatory signaling, reduction of glutamate-induced excitotoxicity, and scavenging of reactive oxygen species. Clinical trials of phlorotannins have not reported significant adverse effects, suggesting these compounds to be promising bioactive agents in the treatment of neurological diseases. We therefore propose a putative biophysical mechanism of phlorotannin action in addition to future directions for phlorotannin research

    Effects of nanofluids containing graphene/graphene-oxide nanosheets on critical heat flux

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    The superb thermal conduction property of graphene establishes graphene as an excellent material for thermal management. In this paper, we selected graphene/graphene oxide nanosheets as the additives in nanofluids. The authors interestingly found that the highly enhanced critical heat flux (CHF) in the nanofluids containing graphene/graphene-oxide nanosheets (GON) cannot be explained by both the improved surface wettability and the capillarity of the nanoparticles deposition layer. Here we highlights that the GON nanofluid can be exploited to maximize the CHF the most efficiently by building up a characteristically ordered porous surface structure due to its own self-assembly characteristic resulting in a geometrically changed critical instability wavelength.open363

    Multifunctional nanoparticles as a tissue adhesive and an injectable marker for image-guided procedures

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    Tissue adhesives have emerged as an alternative to sutures and staples for wound closure and reconnection of injured tissues after surgery or trauma. Owing to their convenience and effectiveness, these adhesives have received growing attention particularly in minimally invasive procedures. For safe and accurate applications, tissue adhesives should be detectable via clinical imaging modalities and be highly biocompatible for intracorporeal procedures. However, few adhesives meet all these requirements. Herein, we show that biocompatible tantalum oxide/silica core/shell nanoparticles (TSNs) exhibit not only high contrast effects for real-time imaging but also strong adhesive properties. Furthermore, the biocompatible TSNs cause much less cellular toxicity and less inflammation than a clinically used, imageable tissue adhesive (that is, a mixture of cyanoacrylate and Lipiodol). Because of their multifunctional imaging and adhesive property, the TSNs are successfully applied as a hemostatic adhesive for minimally invasive procedures and as an immobilized marker for image-guided procedures.

    The First Successful Transapical Aortic Valve Implant in Korea

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    Transcatheter aortic valve implantation is an alternative to open heart surgery in high risk patients with severe aortic stenosis. High mortality and complications related to cardiopulmonary bypass for conventional open heart surgery can be avoided with this new less invasive technique. In case of concomitant severe arterial disease, the transapical approach is recommended rather than transfemoral access. An 80-yr-old man with symptomatic aortic stenosis and who had very high surgical risk factors such as diabetes mellitus, hypertension, a history of stroke, bronchial asthma including poor pulmonary function and hepatocellular carcinoma was treated with a transapical aortic valve replacement. The expected mortality in this patient was 25.4% by Euroscore if we performed the conventional aortic valve surgery. The patient was discharged and was well at the 45 follow-up days. We report the first case of successful transcatheter transapical aortic valve implantation which is available recently in Korea

    Enhanced Crystallinity of Epitaxial Graphene Grown on Hexagonal SiC Surface with Molybdenum Plate Capping

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    The crystallinity of epitaxial graphene (EG) grown on a Hexagonal-SiC substrate is found to be enhanced greatly by capping the substrate with a molybdenum plate (Mo-plate) during vacuum annealing. The crystallinity enhancement of EG layer grown with Mo-plate capping is confirmed by the significant change of measured Raman spectra, compared to the spectra for no capping. Mo-plate capping is considered to induce heat accumulation on SiC surface by thermal radiation mirroring and raise Si partial pressure near surface by confining the sublimated Si atoms between SiC substrate and Mo-plate, which would be the essential contributors of crystallinity enhancementclose0

    The effect of periodontitis on recipient outcomes after kidney transplantation

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    Background Recent several reports have demonstrated that periodontitis is prevalent and adversely affects the survival in patients with chronic kidney disease (CKD) or end-stage kidney disease. However, its impact on transplant outcomes remains uncertain. Methods This retrospective cohort study included 136 and 167 patients, respectively, who underwent living donor kidney transplantation (KT) at Seoul National University Hospital from July 2012 to August 2016 and Korea University Hospital from April 2008 to October 2018. We divided patients into three groups according to stages of periodontitis based on a new classification system. Results Patients with severe periodontitis were older, had a higher prevalence of diabetes, a higher body mass index and C-reactive protein level, a lower cardiac output, and were more likely to be smokers, indicating its association with chronic systemic inflammation. After KT, stage IV periodontitis was independently associated with a lower incidence of acute T cell-mediated rejection, suggesting the possible effect of periodontitis on immune function. However, 1-year and 3-year estimated glomerular filtration rates were not different. Among the KT recipients followed up more than 3 years, new-onset cardiovascular disease occurred in nine patients, and coronary artery disease occurred more frequently in patients with stage IV periodontitis. However, diabetes was the independent predictor of new-onset coronary artery disease in multivariate logistic regression analysis. Conclusion Our findings showed that periodontitis might be an important player in determining posttransplant outcomes in recipients. Further interventional trials to test whether treating periodontitis could modify transplant outcome are needed
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