Resveratrol attenuates lipopolysaccharide-induced dysfunction of blood-brain barrier in endothelial cells via AMPK activation

Min Hu,Bo Liu 대한생리학회-대한약리학회 2016 The Korean Journal of Physiology & Pharmacology Vol.20 No.4

Resveratrol, a phytoalexin, is reported to activate AMP-activated protein kinase (AMPK) in vascular cells. The blood-brain barrier (BBB), formed by specialized brain endothelial cells that are interconnected by tight junctions, strictly regulates paracellular permeability to maintain an optimal extracellular environment for brain homeostasis. The aim of this study was to elucidate the effects of resveratrol and the role of AMPK in BBB dysfunction induced by lipopolysaccharide (LPS). Exposure of human brain microvascular endothelial cells (HBMECs) to LPS (1μg/ml) for 4 to 24 hours week dramatically increased the permeability of the BBB in parallel with lowered expression levels of occluding and claudin-5, which are essential to maintain tight junctions in HBMECs. In addition, LPS significantly increased the reactive oxygen species (ROS) productions. All effects induced by LPS in HBVMCs were reversed by adenoviral overexpression of superoxide dismutase, inhibition of NAD(P)H oxidase by apocynin or gain-function of AMPK by adenoviral overexpression of constitutively active mutant (AMPK-CA) or by resveratrol. Finally, upregulation of AMPK by either AMPK-CA or resveratrol abolished the levels of LPS-enhanced NAD(P)H oxidase subunits protein expressions. We conclude that AMPK activation by resveratrol improves the integrity of the BBB disrupted by LPS through suppressing the induction of NAD(P)H oxidase-derived ROS in HBMECs.

Generation of Realistic Terrain Based on LOD Simplification and Fractal

Min, Hu,Zhen, Wang Society for Computational Design and Engineering 2008 International Journal of CAD/CAM Vol.8 No.1

Based on the study of Digital Elevation Simplification Model and fractal theory, this paper put forward a new method to simulate complex terrain. That use simplified DEM data to construct terrain frame based on the quad tree at first, and then use fractal to generate the details of every node of the tree. In the process of construction, the LOD theory is used to simplify the terrain and get its typical data. According to the change of view position and direction, the paper gives a new way to judge the visibility of the surface patch. Experimental results show that this algorithm is simple, efficient and supports the real time dynamic simulation of terrain model.

Preparation of Monolithic Carbon Xerogels with Graphene Oxide for Electrode Application

Huang Minhu,윤태호 한국고분자학회 2019 한국고분자학회 학술대회 연구논문 초록집 Vol.44 No.1

Specific Capacitance of Monolithic Carbon Xerogel from Resorcinol and Formaldehyde with Mildly Oxidized Graphene for Supercapacitor Electrode

Huang Minhu,윤태호 한국고분자학회 2019 한국고분자학회 학술대회 연구논문 초록집 Vol.44 No.2

Diagnosis of inflammatory bowel disease in Asia: the results of a multinational web-based survey in the 2nd Asian Organization for Crohn`s and Colitis (AOCC) meeting in Seoul

( Eun Soo Kim ),( Minhu Chen ),( Jun Lee ),( Chang-kyun Lee ),( You Sun Kim ) 대한장연구학회 2016 Intestinal Research Vol.14 No.3

Background/Aims: As the number of Asian patients with inflammatory bowel disease (IBD) has increased recently, there is a growing need to improve IBD care in this region. This study is aimed at determining how Asian countries are currently dealing with their IBD patients in terms of diagnosis. Methods: A questionnaire was designed by the organizing committee of Asian Organization for Crohn’s and Colitis, for a multinational web-based survey conducted between March 2014 and May 2014. Results: A total of 353 Asian medical doctors treating IBD patients responded to the survey (114 in China, 88 in Japan, 116 in Korea, and 35 in other Asian countries). Most of the respondents were gastroenterologists working in an academic teaching hospital. While most of the doctors from China, Japan, and Korea use their own national guidelines for IBD diagnosis, those from other Asian countries most commonly adopt the European Crohn’s Colitis Organisation’s guideline. Japanese doctors seldom adopt the Montreal classification for IBD. The most commonly used activity scoring system for ulcerative colitis is the Mayo score in all countries except China, whereas that for Crohn’s disease (CD) is the Crohn’s Disease Activity Index. The most available tool for small-bowel evaluation in CD patients differs across countries. Many physicians administer empirical antituberculous medications before the diagnosis of CD. Conclusions: The results of this survey demonstrate that Asian medical doctors have different diagnostic approaches for IBD. This knowledge would be important in establishing guidelines for improving the care of IBD patients in this region.

Comparisons of the volumetric efficiency and combustion characteristics between CNG-DI and CNG-PFI engines

Song, Jingeun,Choi, Minhu,Park, Sungwook Elsevier 2017 Applied thermal engineering Vol.121 No.-

<P><B>Abstract</B></P> <P>In the present study, the volumetric efficiency and combustion characteristics of compressed natural gas (CNG) direct injection (DI) and port fuel injection (PFI) were compared. In a single-cylinder engine, various fuel injection timings were tested for each fuel injection position, and the volumetric efficiency of each test condition was calculated from the intake flow rate. The one-dimensional simulation program AMESim was also used to further investigate the intake process. Experimental and numerical results showed that the volumetric efficiency was not influenced by the position of the injector. For the early fuel injection, before the intake valve close (IVC), the volumetric efficiencies of the DI and PFI were similar to each other; the averaged volumetric efficiencies were both about 38.62% and the standard deviations of volumetric efficiency were less than 0.2%. However, as the fuel injection timing was retarded after the IVC, the volumetric efficiency of DI increased while the volumetric efficiency of PFI was kept constant or slightly decreased. The increase in the volumetric efficiency was due to the fact that the fuel volume did not occupy the cylinder volume during the intake stroke. Combustion was stable for all the test conditions. The coefficient of variation of the indicated mean effective pressure (COV<SUB>IMEP</SUB>) was lower than 1.5%. The highest fuel conversion efficiency was observed for late fuel direct injection, after the IVC, due to the fastest combustion. Thus, by applying the late fuel injection timing after IVC, the CNG-DI could have a higher volumetric efficiency and fuel conversion efficiency than the CNG-PFI.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Volumetric efficiencies of DI and PFI were similar for early injection conditions. </LI> <LI> 1D simulation code (AMESim) was used to investigate the intake process in detail. </LI> <LI> For various injection timings, the volumetric efficiency of PFI was kept constant. </LI> <LI> Late fuel DI increased volumetric efficiency and fuel conversion efficiency. </LI> <LI> DI after IVC was the best injection strategy for high engine power and efficiency. </LI> </UL> </P>

자율주행 알고리즘 개발을 위한 인공지능모델 개발키트

조흥래(Heungrae Cho),오민후(Minhu Oh),박재민(Jaemin Park) 한국자동차공학회 2022 한국자동차공학회 학술대회 및 전시회 Vol.2022 No.11

Expectation for mass production of the autonomous vehicle is getting bigger as artificial intelligence technology is getting more sophisticated. For a mass production of autonomous vehicle, it is important to secure hardware acceleration cores based on neural processing unit in embedded system and recognition algorithm software based on data coming from real time end point sensors. Especially precision of recognition algorithm running on neural processing unit and work-flow efficiency for algorithm development is essential to make a success in mass production of autonomous vehicle. To respond promptly to automotive mass production process while developing vision recognition algorithm based on artificial intelligent model, it is needed to set up efficient development infra environment to reduce time consumed in implementing, training, analyzing and testing artificial intelligent model. In this paper, development concept, software architecture and functional description of artificial intelligent model development kit for training and analyzing various models are introduced as well as direction of improvement in artificial intelligent model development kit to maximize development speed and synergy effect of related work area. The artificial intelligent model development kit introduced in this paper includes training, analyzing, evaluation, and release tools for artificial intelligent model development. From now on, let’s call artificial intelligent model development kit as AI MDK simply. The goal of AI MDK introduced in this paper is to make explainable AI model development environment infra, other than seeing AI model as a black box as conventionally regarded.

Esophageal Baseline Impedance Reflects Mucosal Integrity and Predicts Symptomatic Outcome With Proton Pump Inhibitor Treatment

( Chenxi Xie ),( Daniel Sifrim ),( Yuwen Li ),( Minhu Chen ),( Yinglian Xiao ) 대한소화기기능성질환·운동학회(구 대한소화관운동학회) 2018 Journal of Neurogastroenterology and Motility (JNM Vol.24 No.1

Background/Aims Esophageal baseline impedance, which is decreased in gastroesophageal reflux disease (GERD) patients, is related to the severity of acid reflux and the integrity of the esophageal mucosa. The study aims to compare the baseline impedance and the dilated intercellular spaces (DIS) within patients with typical reflux symptoms and to evaluate the correlation of baseline impedance with DIS, esophageal acid exposure, as well as the efficacy of proton pump inhibitor (PPI) treatment. Methods Ninety-two patients and 10 healthy controls were included in the study. Erosive esophagitis (EE) was defined by esophageal mucosal erosion under upper endoscopy. Patients without mucosa erosion were divided into groups with pathologic acid reflux (non-erosive reflux disease [NERD]) or with hypersensitive esophagus. The biopsies of esophageal mucosa were taken 2-4 cm above the gastroesophageal junction Z-line during upper endoscopy for DIS measurement. All the patients received esomeprazole 20 mg twice-daily treatment for 8 weeks. The efficacy of esomeprazole was evaluated among all patients. Results The intercellular spaces were dilated in both EE and NERD patients (P < 0.05). The value 0.73 mm could be used as the cut-off DIS value to distinguish patients from controls (area under the curve [AUC] = 0.849, P < 0.01). One thousand seven hundred sixty-four ohms could be used as the cut-off impedance values to distinguish patients from controls (AUC = 0.794, P < 0.01). The baseline impedance was decreased in both EE patients and NERD patients, and negatively correlated to the acid exposure time (r = -0.527, P < 0.05). There was a weak correlation between DIS and baseline impedance (r = -0.230, P < 0.05). “Baseline impedance > 1764 Ω” was an independent predictor for PPI failure (OR, 11.9; 95% CI, 2.4-58.9; P < 0.01). Conclusions The DIS and decreased baseline impedance was observed in patients with mucosa erosion or pathological acid reflux. The baseline impedance reflected the mucosal integrity, it was more sensitive to esophageal acid exposure. Patients with high impedance might not benefit from the PPI treatment. (J Neurogastroenterol Motil 2018;24:43-50)

Asian Organization for Crohn’s and Colitis and Asia Pacific Association of Gastroenterology consensus on tuberculosis infection in patients with inflammatory bowel disease receiving anti-tumor necrosis factor treatment. Part 1: risk assessment

( Dong Il Park ),( Tadakazu Hisamatsu ),( Minhu Chen ),( Siew Chien Ng ),( Choon Jin Ooi ),( Shu Chen Wei ),( Rupa Banerjee ),( Ida Normiha Hilmi ),( Yoon Tae Jeen ),( Dong Soo Han ),( Hyo Jong Kim ) 대한장연구학회 2018 Intestinal Research Vol.16 No.1

Because anti-tumor necrosis factor (anti-TNF) therapy has become increasingly popular in many Asian countries, the risk of developing active tuberculosis (TB) among anti-TNF users may raise serious health problems in this region. Thus, the Asian Organization for Crohn’s and Colitis and the Asia Pacific Association of Gastroenterology have developed a set of consensus statements about risk assessment, detection and prevention of latent TB infection, and management of active TB infection in patients with inflammatory bowel disease (IBD) receiving anti-TNF treatment. Twenty-three consensus statements were initially drafted and then discussed by the committee members. The quality of evidence and the strength of recommendations were assessed by using the Grading of Recommendations Assessment, Development, and Evaluation methodology. Web- based consensus voting was performed by 211 IBD specialists from 9 Asian countries concerning each statement. A consensus statement was accepted if at least 75% of the participants agreed. Part 1 of the statements comprised 2 parts: risk of TB infection Recommenda-during anti-TNF therapy, and screening for TB infection prior to commencing anti-TNF therapy. These consensus statements will help clinicians optimize patient outcomes by reducing the morbidity and mortality related to TB infections in patients with IBD receiving anti-TNF treatment. (Intest Res 2018;16:4-16)

Relationship Between Salivary Pepsin Concentration and Esophageal Mucosal Integrity in Patients With Gastroesophageal Reflux Disease

( Yu-wen Li ),( Daniel Sifrim ),( Chenxi Xie ),( Minhu Chen ),( Ying-lian Xiao ) 대한소화기기능성질환·운동학회(구 대한소화관운동학회) 2017 Journal of Neurogastroenterology and Motility (JNM Vol.23 No.4

Background/Aims Increased salivary pepsin could indicate an increase in gastro-esophageal reflux, however, previous studies failed to demonstrate a correlation between salivary pepsin concentrations and 24-hour esophageal acid exposure. This study aims to detect the salivary pepsin and to evaluate the relationship between salivary pepsin concentrations and intercellular spaces (IS) in different gastroesophageal reflux disease phenotypes in patients. Methods A total of 45 patients and 11 healthy volunteers were included in this study. All subjects underwent upper gastrointestinal endoscopy, 24-hour ambulatory multichannel impedance-pH (MII-pH) monitoring, and salivary sampling at 3-time points during the 24-hour MII-pH monitoring. IS were measured by transmission electron microscopy, and salivary pepsin concentrations were determined by enzyme-linked immunosorbent assay. Results The IS measurements were greater in the esophagitis (EE), non-erosive reflux disease (NERD), and hypersensitive esophagus (HO) groups than in the functional heartburn (FH) and healthy volunteer groups, and significant differences were indicated. Patients with NERD and HO had higher average pepsin concentrations compared with FH patients. A weak correlation was determined between IS and salivary pepsin among patients with NERD (r = 0.669, P = 0.035). Conclusions We confirmed the presence of a higher level of salivary pepsin in patients with NERD than in patients with FH. Salivary pepsin concentrations correlated with severity of mucosal integrity impairment in the NERD group. We suggest that in patients with NERD, low levels of salivary pepsin can help identify patients with FH, in addition the higher the pepsin concentration, the more likely the severity of dilated IS. (J Neurogastroenterol Motil 2017;23:517-525)