The Effect of Peripheral CRF Peptide and Water Avoidance Stress on Colonic and Gastric Transit in Guinea Pigs

Zahid Hussain,박효진,김혜원,허철웅,이영주 연세대학교의과대학 2017 Yonsei medical journal Vol.58 No.4

Functional dyspepsia (FD) and irritable bowel syndrome (IBS) are common gastrointestinal (GI) diseases; however, there is frequent overlap between FD and IBS patients. Emerging evidence links the activation of corticotropin releasing factor (CRF) receptors with stress-related alterations of gastric and colonic motor function. Therefore, we investigated the effect of peripheral CRF peptide and water avoidance stress (WAS) on upper and lower GI transit in guinea pigs. Dosages 1, 3, and 10 μg/kg of CRF were injected intraperitoneally(IP) in fasted guinea pigs 30 minutes prior to the intragastric administration of charcoal mix to measure upper GI transit. Colonic transits in non-fasted guinea pigs were assessed by fecal pellet output assay after above IP CRF doses. Blockade of CRF receptorsby Astressin, and its effect on GI transit was also analyzed. Guinea pigs were subjected to WAS to measure gastrocolonic transit in different sets of experiments. Dose 10 μg/kg of CRF significantly inhibited upper GI transit. In contrast, there was dose dependentacceleration of the colonic transit. Remarkably, pretreatment of astressin significantly reverses the effect of CRF peptide on GI transit. WAS significantly increase colonic transit, but failed to accelerate upper GI transit. Peripheral CRF peptide significantly suppressed upper GI transit and accelerated colon transit, while central CRF involved WAS stimulated only colonic transit. Therefore,peripheral CRF could be utilized to establish the animal model of overlap syndrome.

Effect of Viscous Drag on Mooring Line Restoring Forces

Zahid Ullah,Naik Muhammad,Dong-Ho Choi 대한토목학회 2016 대한토목학회 학술대회 Vol.2016 No.10

PKR as a Regulator of Inflammasome Activation

Zahid Manzoor,Young-Sang Koh 대한미생물학회 2013 Journal of Bacteriology and Virology Vol.43 No.2

The Effect of Trimebutine on the Overlap Syndrome Model of Guinea Pigs

( Zahid Hussain ),( Da Hyun Jung ),( Young Ju Lee ),( Hyojin Park ) 대한소화기기능성질환·운동학회(구 대한소화관운동학회) 2018 Journal of Neurogastroenterology and Motility (JNM Vol.24 No.4

Background/Aims Functional dyspepsia (FD) and irritable bowel syndrome (IBS) are common gastrointestinal (GI) disorders and these patients frequently overlap. Trimebutine has been known to be effective in controlling FD co-existing diarrhea-dominant IBS, however its effect on overlap syndrome (OS) patients has not been reported. Therefore, we investigated the effect of trimebutine on the model of OS in guinea pigs. Methods Male guinea pigs were used to evaluate the effects of trimebutine in corticotropin-releasing factor (CRF) induced OS model. Different doses (3, 10, and 30 mg/kg) of trimebutine were administered orally and incubated for 1 hour. The next treatment of 10 μg/kg of CRF was intraperitoneally injected and stabilized for 30 minutes. Subsequently, intragastric 3 mL charcoal mix was administered, incubated for 10 minutes and the upper GI transit analyzed. Colonic transits were assessed after the same order and concentrations of trimebutine and CRF treatment by fecal pellet output assay. Results Different concentrations (1, 3, and 10 μg/kg) of rat/human CRF peptides was tested to establish the OS model in guinea pigs. CRF 10 μg/kg was the most effective dose in the experimental OS model of guinea pigs. Trimebutine (3, 10, and 30 mg/kg) treatment significantly reversed the upper and lower GI transit of CRF induced OS model. Trimebutine significantly increased upper GI transit while it reduced fecal pellet output in the CRF induced OS model. Conclusions Trimebutine has been demonstrated to be effective on both upper and lower GI motor function in peripheral CRF induced OS model. Therefore, trimebutine might be an effective drug for the treatment of OS between FD and IBS patients. (J Neurogastroenterol Motil 2018;24:669-675)

Microstructural characterization of mullite and anorthitebased Porcelain tile using regional clay

Zahide Bayer Ozturk 한양대학교 세라믹연구소 2016 Journal of Ceramic Processing Research Vol.17 No.6

The study focused on using of regional clay (Nevsehir/Turkey) instead of different clay and kaolin to prepare porcelain tilesalong with dolomite and albite. Considering the variation of regional clay with other clay and kaolin the physical properties,phase-microstructure analysis and the determination of sintering temperatures by means of optical dilatometer of sampleswere studied. Uni-axially pressed samples were exposed to firing regime at 1205 oC for 42 min and tested to comply with ISO10545 tile standards. The crystal phases were detected as quartz, anorthite and mullite. The mechanical strength was foundto increase as the mullite content. When the Nevsehir’s clay content in the starting composition added, glassy matrix becamericher in kaolinite glass and earth-alkaline oxide favorably affected the sintering temperatures. Almost all technologicalproperties and sintering behavior of new compositions demonstrated the suitability of Nevsehir clay as a potential raw materialfor ceramic tile industry. This regional clay is affect to microstructure and crystalline phases of tile bodies.

Enhanced Predictive Modelling of Steel Corrosion in Concrete in Submerged Zone Based on a Dynamic Activation Approach

Zahid Mohammad Mir,Daniel Hoche,Celestino Gomes,Rui Sampaio,Alexandre C. Bastos,Philippe Maincon,M. G. S. Ferreira,Mikhail L. Zheludkevich 한국콘크리트학회 2019 International Journal of Concrete Structures and M Vol.13 No.1

A numerical model for enhanced service life prediction of concrete infrastructure is presented which includes transient analysis of processes during corrosion initiation as well as propagation stage. The temporal and spatial transition of Steel–Concrete Interface during depassivation events is described by a randomly varying chloride threshold function. As such random activation events can be accounted for, rather than having to pre-describe the anode size and location as in many existing models. The aim of the study is to investigate random spatial activation events in concrete structures in submerged zones based on dynamically changing boundary conditions on the rebar surface to control transition from passive to active state. Investigations are carried out to realize the sustainability of corrosion processes in limiting oxygen concentrations in dissolved seawater. The model showcases the numerical architecture, the associated concept of randomly varying chloride threshold and predicts that among other factors, the rate of oxygen strongly influences corrosion rate in submerged locations.

An investigation of the effect of alkaline oxides on porcelain tiles using factorial design

Zahide Bayer Ozturk 한양대학교 세라믹연구소 2012 Journal of Ceramic Processing Research Vol.13 No.5

In this study, the effect of alkaline oxides (MgO, CaO, Na2O and K2O) was investigated in porcelain tile compositions. Talc (MgO) and dolomitic clay (CaO, MgO) were added to porcelain tile compositions instead of feldspar (Na2O, K2O). In the experiments 21 × 32 mixed-level factorial design was used, the individual effects of three main factors and their interactions were determined. The effect of the amount of talc (0, 2, 4 wt. %), dolomitic clay (0, 2, 4 wt. %) and firing conditions (1, 2) on porcelain tile properties were examined. Firing shrinkage, water absorption and the strength of samples were studied by means of factorial design. The porosity and bulk density of samples, color measurement and SEM analyses of these samples were also investigated. It was found that the strength increased and water absorption decreased by means of alkaline oxides variation in the porcelain tile body. According to factorial design, it has been found that the amount of dolomitic clay and talc are the main factors affecting the strength, firing shrinkage and water absorption values. It appeared that the magnitude of these properties were dependent on the amount of alkaline-earth oxides (CaO, MgO).

단순 2단계 공정으로 합성한 그래핀 강화 CuNi 복합재료

( Zahid Hussaina ),이정수 ( Jung-soo Lee ),최병상 ( Byung-sang Choi ) 조선대학교 공학기술연구원 2021 공학기술논문지 Vol.14 No.4

In this work, a three-dimensionally interconnected network of graphene-reinforced CuNi (3DiGr-CuNi) composite was fabricated by a simple two-step process in which Cu and Ni powders were compacted into a disk by applying an appropriate compaction pressure, followed by chemical vapor deposition. By using various characterization tools such as optical microscopy, scanning electron microscopy, and X-ray diffraction analysis, it was found that there are certain optimum conditions for producing a three-dimensionally interconnected network of grapheme (3DiGr) in a CuNi matrix. It was also shown that a slightly modified surface of the three-dimensionally reinforced composite can be used as a cathode in fuel cells. In addition, it was found that the thermal conductivity of the 3DiGr-CuNi composite was ~58% higher than that of PM CuNi alloy (without reinforcement), which can be explained by the ability of 3DiGr to provide conducting channels for electron mobility. Moreover, the 3DiGr-CuNi composite showed lower corrosion current density and negative potential during a potentiodynamic polarization experiment, indicating better corrosion resistance than PM CuNi alloy. Uniaxial tensile tests showed 14.8% and 14.5% higher yield and tensile strengths, respectively, of the 3DiGr-CuNi composite compared with PM CuNi alloy.

Face Spoofing Attack Detection Using Spatial Frequency and Gradient-Based Descriptor

( Zahid Ali ),( Unsang Park ) 한국인터넷정보학회 2019 KSII Transactions on Internet and Information Syst Vol.13 No.2

Biometric recognition systems have been widely used for information security. Among the most popular biometric traits, there are fingerprint and face due to their high recognition accuracies. However, the security system that uses face recognition as the login method are vulnerable to face-spoofing attacks, from using printed photo or video of the valid user. In this study, we propose a fast and robust method to detect face-spoofing attacks based on the analysis of spatial frequency differences between the real and fake videos. We found that the effect of a spoofing attack stands out more prominently in certain regions of the 2D Fourier spectra and, therefore, it is adequate to use the information about those regions to classify the input video or image as real or fake. We adopt a divide-conquer-aggregate approach, where we first divide the frequency domain image into local blocks, classify each local block independently, and then aggregate all the classification results by the weighted-sum approach. The effectiveness of the methodology is demonstrated using two different publicly available databases, namely: 1) Replay Attack Database and 2) CASIA-Face Anti-Spoofing Database. Experimental results show that the proposed method provides state-of-the-art performance by processing fewer frames of each video.

Bacterial 23S Ribosomal RNA, a Ligand for Toll-like Receptor 13

Zahid Manzoor,Young-Sang Koh 대한미생물학회 2012 Journal of Bacteriology and Virology Vol.42 No.4

Toll-like receptors are required for detection of pathogen-associated molecular patterns and play critical roles in protection of host from infection. Murine TLR13 was recently reported to be involved in recognition of bacterial 23S ribosomal RNA sequence that is the binding site of different antibiotics.