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Background/aims: Gastrointestinal bleeding (GIB) risk for non-vitamin K antagonist oral anticoagulants (NOACs) compared with warfarin is largely unknown. We aimed to determine the risk of overall and post-polypectomy GIB for NOACs and warfarin., Methods: Using the Korean National Health Insurance database, we created a cohort of patients who were newly prescribed NOACs or warfarin between July 2015 and December 2017 using propensity score matching (PSM). Kaplan-Meier analysis with log-rank test was performed to compare the risk of overall and post-polypectomy GIB between NOACs (apixaban, dabigatran, and rivaroxaban) and warfarin. Post-polypectomy GIB was defined as bleeding within 1 month after gastrointestinal endoscopic polypectomy., Results: Out of 234,206 patients taking anticoagulants (187,687 NOACs and 46,519 warfarin), we selected 39,764 pairs of NOACs and warfarin users after PSM. NOACs patients showed significantly lower risk of overall GIB than warfarin patients (log-rank P<0.001, hazard ratio, 0.86; 95% confidence interval, 0.78-0.94; P=0.001). Among NOACs, apixaban showed the lowest risk of GIB. In the subgroup of 7,525 patients who underwent gastrointestinal polypectomy (lower gastrointestinal polypectomy 93.1%), 1,546 pairs were chosen for each group after PSM. The NOACs group showed a high risk of post-polypectomy GIB compared with the warfarin group (log-rank P=0.001, hazard ratio, 1.97; 95% confidence interval, 1.16-3.33; P=0.012)., Conclusions: This nationwide, population-based study demonstrates that risk of overall GIB is lower for NOACs than for warfarin, while risk of post-polypectomy GIB is higher for NOACs than for warfarin.

Objective: Amniotic mesenchymal stromal cells (AMSCs) can be obtained from the mesoderm of human amniotic membrane. AMSCs derived from term baby show increased expression of genes associated with apoptosis and senescence. The objective of this study was to examine gene expression profiles of AMSCs derived from preterm (preterm AMSCs) and term labors (term AMSCs) and analyze common and different mechanisms., Materials and Methods: We isolated and cultured AMSCs from 43 placentas: 27 from term labor and 16 from preterm labor. Microarray analysis and gene network analysis were performed to compare gene expression profile (GEP) of preterm (n = 6) with term AMSCs (n = 10). Senescence-associated gene (CDKN2A and CDKN2B) expression was also measured by reverse transcription quantitative PCR., Results: GEP demonstrated that preterm AMSCs showed upregulation of nicotinamide adenine dinucleotide biosynthetic process and downregulation of extracellular matrix, cholesterol import and transport, lipid storage, and maintenance of location. CDKN2A and CDKN2B genes showed similar expression levels between term and preterm AMSCs. CDKN2A gene expression was correlated with CDKN2B expression and population doubling time. Compared to term AMSCs, preterm AMSCs showed significantly different expression of genes associated with inflammatory response which could be one of the major players in labor events., Conclusion: Increased CDKN2A expression in AMSCs is associated with placental membrane aging which participates in both preterm and term labor. To the best of our knowledge, this is the first report to demonstrate the association of AMSCs with labor., Competing Interests: Declaration of competing interest The authors declare that they have no competing interests., (Copyright © 2021. Published by Elsevier B.V.)

Precise control of light is indispensable to modern optical communication devices especially as the size of such devices approaches the subwavelength scale. Plasmonic devices are suitable for the development of these optical devices due to the extreme field confinement and its ability to be controlled by tuning the carrier density at the metal/dielectric interface. Here, an electro-ionic controlled plasmonic device consisting of Au/graphene/ion-gel is demonstrated as an optical switch, where an external electric field modulates the real part of the electrical conductivity. The graphene layer enhances charge penetration and charge separation at the Au/graphene interface resulting in an increased photoinduced voltage. The ion-gel immobilized on the Au/graphene further enables the electrical tunability of plasmons which modulates the intensity of the reflected laser light. This work paves the way for developing novel plasmonic electro-optic switches for potential applications such as integrated optical devices.

A theoretical model based on the coupled mode theory is presented to calculate the absorption in a graphene embedded 1D guided-mode-resonance (GMR) structure that does not require a back reflector. The optimized graphene-GMR structure can absorb up to 70% of the incident light which far exceeds the already reported results without using any back-metal reflector or Bragg mirror. The theoretical analysis is valid for binary gratings and pyramidal gratings which are patterned using an interference lithography system. We experimentally validate our theoretical results and analyze the influence of the geometrical parameters to achieve critical coupling for the enhanced absorption.