1,625 research outputs found
Virtual Earthquake Engineering Laboratory Capturing Nonlinear Shear, Localized Damage and Progressive Buckling of Bar
We embarked upon developing a novel parallel simulation platform that is rooted in microphysical mechanisms. Primarily aiming at large-scale reinforced-concrete structures exposed to cyclic loading, we sought to settle the question as to how to capture nonlinear shear, localized damage and progressive buckling of reinforcing bar. We proposed a tribology-inspired three-dimensional (3-D) interlocking mechanism in the well-established framework of multidirectional smeared crack models. Strong correlation between random material property and localized damage has been shown, notably at the global system level. An automated platform has been suggested to capture progressive buckling phenomena. Validation and applications straddle a wide range, from small laboratory tests to large-scale 3-D experiments, successfully offering a clear causal pathway between underlying physical mechanisms and the unresolved issues addressed above
Replica molding-based nanopatterning of tribocharge on elastomer with application to electrohydrodynamic nanolithography
Replica molding often induces tribocharge on elastomers. To date, this phenomenon has been studied only on untextured elastomer surfaces even though replica molding is an effective method for their nanotexturing. Here we show that on elastomer surfaces nanotextured through replica molding the induced tribocharge also becomes patterned at nanoscale in close correlation with the nanotexture. By applying Kelvin probe microscopy, electrohydrodynamic lithography, and electrostatic analysis to our model nanostructure, poly(dimethylsiloxane) nanocup arrays replicated from a polycarbonate nanocone array, we reveal that the induced tribocharge is highly localized within the nanocup, especially around its rim. Through finite element analysis, we also find that the rim sustains the strongest friction during the demolding process. From these findings, we identify the demolding-induced friction as the main factor governing the tribochargeās nanoscale distribution pattern. By incorporating the resulting annular tribocharge into electrohydrodynamic lithography, we also accomplish facile realization of nanovolcanos with 10ānm-scale craters
Effects of a multi-herbal extract on type 2 diabetes
<p>Abstract</p> <p>Background</p> <p>An aqueous extract of multi-hypoglycemic herbs of <it>Panax ginseng </it>C.A.Meyer, <it>Pueraria lobata, Dioscorea batatas Decaisne, Rehmannia glutinosa, Amomum cadamomum LinnĆ©, Poncirus fructus </it>and <it>Evodia officinalis </it>was investigated for its anti-diabetic effects in cell and animal models.</p> <p>Methods</p> <p>Activities of PPARĪ³ agonist, anti-inflammation, AMPK activator and anti-ER stress were measured in cell models and in <it>db/db </it>mice (a genetic animal model for type 2 diabetes).</p> <p>Results</p> <p>While the extract stimulated PPARĪ³-dependent luciferase activity and activated AMPK in C2C12 cells, it inhibited TNF-Ī±-stimulated IKKĪ²/NFkB signaling and attenuated ER stress in HepG2 cells. The <it>db/db </it>mice treated with the extract showed reduced fasting blood glucose and HbA<sub>1c </sub>levels, improved postprandial glucose levels, enhanced insulin sensitivity and significantly decreased plasma free fatty acid, triglyceride and total cholesterol.</p> <p>Conclusion</p> <p>The aqueous extract of these seven hypoglycemic herbs demonstrated many therapeutic effects for the treatment of type 2 diabetes in cell and animal models.</p
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Comparison of the Plasma Metabolome Profiles Between the Internal Thoracic Artery and Ascending Aorta in Patients Undergoing Coronary Artery Bypass Graft Surgery Using Gas Chromatography Time-of-Flight Mass Spectrometry.
BackgroundThe left internal thoracic artery (LITA) has been used as the first conduit of choice in coronary artery bypass grafting (CABG) because of excellent long-term patency and outcomes. However, no studies have examined substances other than nitric oxide that could be beneficial for the bypass conduit, native coronary artery or ischemic myocardium. This study was conducted to evaluate differences in metabolic profiles between the LITA and ascending aorta using gas chromatography-time of flight-mass spectrometry (GC-TOF-MS).MethodsTwenty patients who underwent CABG using the LITA were prospectively enrolled. Plasma samples were collected simultaneously from the LITA and ascending aorta. GC-TOF-MS based untargeted metabolomic analyses were performed and a 2-step volcano plot analysis was used to identify distinguishable markers from two plasma metabolome profiles. Semi-quantitative and quantitative analyses were performed using GC-TOF-MS and enzyme-linked immunosorbent assay, respectively, after selecting target metabolites based on the metabolite set enrichment analysis.ResultsInitial volcano plot analysis demonstrated 5 possible markers among 851 peaks detected. The final analysis demonstrated that the L-cysteine peak was significantly higher in the LITA than in the ascending aorta (fold change = 1.86). The concentrations of intermediate metabolites such as L-cysteine, L-methionine and L-cystine in the 'cysteine and methionine metabolism pathway' were significantly higher in the LITA than in the ascending aorta (2.0-, 1.4- and 1.2-fold, respectively). Quantitative analysis showed that the concentration of hydrogen sulfide (HāS) was significantly higher in the LITA.ConclusionThe plasma metabolome profiles of the LITA and ascending aorta were different, particularly higher plasma concentrations of L-cysteine and HāS in the LITA
SECBlock-IIoT : A Secure Blockchain-enabled Edge Computing Framework for Industrial Internet of Things
This work was supported by a National Research Foundation of Korea (NRF) grant funded by Korean Government (MSIT) (No. 2021R1A2C2014333).Postprin
The Risk of Stress Urinary Incontinence After Hysterectomy for Uterine Fibroids
Purpose We evaluated the relationship between previous hysterectomy for uterine fibroids and subsequent stress urinary incontinence (SUI). Methods This study analyzed national health insurance data. The hysterectomy group (aged 40 to 59) comprised patients who underwent hysterectomy for uterine fibroids between January 1, 2011 and December 31, 2014, and the control group (aged 40 to 59) comprised patients who visited a medical facility for a checkup during the same time span. One-to-one propensity score matching was performed to balance confounders. SUI was defined as the need for SUI surgery accompanied by a diagnosis code for SUI. Results After matching, 81,373 cases (hysterectomy group) and 81,373 controls (nonhysterectomy group) were enrolled. The mean follow-up period was 7.9 years for the cases and 7.8 years for the controls. The incidence of anti-incontinence surgery was slightly but significantly higher in the cases than in the controls (2.0% vs. 1.7%, P<0.001). Compared to the control group, abdominal hysterectomy significantly increased the likelihood of anti-incontinence surgery both before (hazard ratio [HR], 1.235; 95% confidence interval [CI], 1.116ā1.365) and after adjusting for confounders (HR, 1.215; 95% CI, 1.097ā1.347). In contrast, laparoscopic hysterectomy, laparoscopic hysterectomy with adnexal surgery, and abdominal hysterectomy with adnexal surgery were not associated with an increased rate of anti-incontinence surgery. The significant association between abdominal hysterectomy and an elevated rate of anti-incontinence surgery persisted even after stratifying patients by age group. Conclusions Prior abdominal hysterectomy without adnexal surgery was associated with an increased incidence of subsequent anti-urinary incontinence surgery
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