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Composite Membrane Containing a Proton Conductive Oxide for Direct Methanol Fuel Cell
Peck, Dong-Hyun,Cho, Sung-Yong,Kim, Sang-Kyung,Jung, Doo-Hwan,Kim, Jeong-Soo The Korean Electrochemical Society 2008 한국전기화학회지 Vol.11 No.1
The composite membrane for direct methanol fuel cell (DMFC) was developed using $H_3O^+-{\beta}"-Al_2O_3$ powder and perfluorosulfonylfluroride copolymer (Nafion) resin. The perfluorosulfonylfluroride copolymer (Nafion) resin was mixed with $H_3O^+-{\beta}"-Al_2O_3$ powder and it was made to sheet form by hot pressing. The electrodes were prepared with 60 wt% PtRu/C and 60wt% Pt/C catalysts for anode and cathode, respectively. The morphology and the chemical composition of the composite membrane have been investigated by using SEM and EDXA, respectively. The composite membrane and $H_3O^+-{\beta}"-Al_2O_3$ were analyzed by using FT-IR and XRD. The methanol permeability of the composite membranes was also measured by gas chromatography (GC). The performance of the MEA containing the composite membrane (2wt% $H_3O^+-{\beta}"-Al_2O_3$) was higher than that of normal pure Nafion membrane at high operating temperature (e.g. $110^{\circ}C$), due to the homogenous distribution of $H_3O^+-{\beta}"-Al_2O_3$, which decreased the methanol permeability through the membrane and enhanced the water contents in the composite membrane.
Peck, Jacquelin,Sapp, Kaitlin,Wilsey, Alexander,Wilsey, Michael The Korean Society of Pediatric Gastroenterology 2019 Pediatric gastroenterology, hepatology & nutrition Vol.22 No.1
Buried bumper syndrome is a rare but potentially severe complication of percutaneous endoscopic gastrostomy tube insertion. Though this complication is uncommon, it may lead to pressure necrosis, bleeding, perforation, peritonitis, sepsis, or death. Each case of buried bumper syndrome is unique in terms of patient comorbidities and anatomic positioning of the buried bumper. For this reason, many approaches have been described in the management of buried bumper syndrome. In this case report, we describe the case of an adolescent Caucasian female who developed buried bumper syndrome three years after undergoing percutaneous endoscopic gastrostomy insertion. We review diagnosis and management of buried bumper syndrome and describe a novel technique for bumper removal in which we use a guide wire in combination with external traction to maintain a patent gastrostomy lumen while removing the internal percutaneous endoscopic gastrostomy bumper.
Endoscopic Balloon Dilation for Treatment of Congenital Antral Web
Peck, Jacquelin,Khalaf, Racha,Marth, Ryan,Phen, Claudia,Sosa, Roberto,Cordero, Francisco Balsells,Wilsey, Michael The Korean Society of Pediatric Gastroenterology 2018 Pediatric gastroenterology, hepatology & nutrition Vol.21 No.4
Congenital antral webs are a rare but relevant cause of gastric outlet obstruction in infants and children. The condition may lead to feeding refusal, vomiting, and poor growth. Due to the relative rarity of the disease, cases of congenital antral web are frequently misdiagnosed or diagnosed with significant delay as physicians favorably pursue diagnoses of pyloric stenosis and gastric ulcer disease, which are more prevalent. We report a case of an eight-month-old female who presented with persistent non-bilious emesis, feeding difficulties, and failure to thrive and was discovered to have an antral web. The web was successfully treated with endoscopic balloon dilation, which resolved her symptoms. Two years later, the patient remains asymptomatic and is thriving with weight at the 75th percentile for her age.
Peck Loo Kiew,Zainal Ahmad,Mashitah Mat Don 한국생물공학회 2013 Biotechnology and Bioprocess Engineering Vol.18 No.2
Fractional factorial design (FFD) was applied to evaluate the effects of various process parameters in influencing the extraction efficiency of pepsin soluble collagen (PSC) from muscles of cultured catfish (Clarias gariepinus×C. macrocephalus). Result of the first order factorial design showed that acetic acid concentration, acid extraction time, acetic acid to muscles ratio, and stirring speed posed significant effect (P<0.05) on the yield of PSC obtained at the end of the extraction process. Two different artificial intelligence techniques namely artificial neural network (ANN) and genetic algorithm (GA) were then integrated for optimizing the extraction conditions to obtain the highest yield of PSC. The ANN was trained using the back propagation algorithm. A model was successfully generated with R2 value of 0.9527 and MSE value of 0.1672 for unseen data set, implying a good generalization of the network. Input parameters of the established ANN model were subsequently optimized using GA. The hybrid of ANN-GA model predicted a maximum extraction yield of PSC at 238.25 mg/g under the following conditions: an acetic acid concentration of 0.70 M, the acetic acid to muscles ratio of 25.78 mL/g,and the stirring speed of 432.50 rpm. Verification of the optimization showed the percentage error differences between the experimental and predicted values were less than 5%, indicating excellent modeling, predicting ability and optimization by the ANN-GA model.
MEASUREMENT OF ICE PACKING FACTOR OF AQUEOUS SOLUTION WITH ICE SLURRY USING REFRACTIVE INDEX
Peck, Jong-Hyeon,Kang, Chae-Dong,Hong, Hi-Ki The Society of Air-Conditioning and Refrigerating 2010 International Journal Of Air-Conditioning and Refr Vol.18 No.2
In the present work, a new method is proposed for the measurement of the ice packing factor (IPF) of an ice slurry using the index of refraction. The purpose of the new method is to improve the resolution of the measurement and to increase its resistance to electric noise as compared to the standard IPF measurement technique that relies on the measurement of the freezing temperature. These two methods are similar in that they both obtain a concentration of aqueous solution from the measured physical quantities and calculate the IPF using the relationship between concentration and IPF. Both methods were also compared with the results from the calorimeter method obtaining the IPF directly. The two methods are in good agreement (within 5%), which demonstrate the validity of the newly proposed method.
Peck, Jacquelin,Nguyen, Anh Thy H.,Dey, Aditi,Amankwah, Ernest K.,Rehman, Mohamed,Wilsey, Michael The Korean Society of Pediatric Gastroenterology 2021 Pediatric gastroenterology, hepatology & nutrition Vol.24 No.1
Purpose: Percutaneous endoscopic gastrostomy (PEG) tube placements are commonly performed pediatric endoscopic procedures. Because of underlying disease, these patients are at increased risk for airway-related complications. This study compares patient characteristics and complications following initial PEG insertion with general endotracheal anesthesia (GETA) vs. anesthesia-directed deep sedation with a natural airway (ADDS). Methods: All patients 6 months to 18 years undergoing initial PEG insertion within the endoscopy suite were considered for inclusion in this retrospective cohort study. Selection of GETA vs. ADDS was made by the anesthesia attending after discussion with the gastroenterologist. Results: This study included 168 patients (GETA n=38, ADDS n=130). Cohorts had similar characteristics with respect to sex, race, and weight. Compared to ADDS, GETA patients were younger (1.5 years vs. 2.9 years, p=0.04), had higher rates of severe American Society of Anesthesiologists (ASA) disease severity scores (ASA 4-5) (21% vs. 3%, p<0.001), and higher rates of cardiac comorbidities (39.5% vs. 18.5%, p=0.02). Significant associations were not observed between GETA/ADDS status and airway support, 30-day readmission, fever, or pain medication in unadjusted or adjusted models. GETA patients had significantly increased length of stay (eβ=1.55, 95% confidence interval [CI]=1.11-2.18) after adjusting for ASA class, room time, anesthesia time, fever, and cardiac diagnosis. GETA patients also had increased room time (eβ=1.20, 95% CI=1.08-1.33) and anesthesia time (eβ=1.50, 95% CI=1.30-1.74) in adjusted models. Conclusion: Study results indicate that younger and higher risk patients are more likely to undergo GETA. Children selected for GETA experienced longer room times, anesthesia times, and hospital length of stay.
Peck Loo Kiew,Mat Don Mashitah,Zainal Ahmad 한국응용생명화학회 2014 Applied Biological Chemistry (Appl Biol Chem) Vol.57 No.1
The empirical kinetic models for the pepsin solublecollagen extraction from the skin of cultured hybrid catfish (Clarissp.) were studied using four two-parametric models, namely thepower law, parabolic diffusion, Peleg’s and Elovich’s models. ThePeleg’s model was found to be the best model capable of predictingthe extraction data with R2 >0.9, p-value >2.0%, and RMSD<10.0%, respectively. Kinetic models based on the second orderrate equation were successfully developed to describe the extractionprocesses with different processing variables. Extraction rateconstant, initial extraction rate and equilibrium concentrations fordifferent acetic acid concentrations, liquid to solid ratios, andpepsin dosages were predicted. The verification of the developedmodels showed that the experimental values agreed with thepredicted ones, with percentage error differences in the range of0.03–3.91%.
Isolation and Characterization of Collagen from the Skin of Malaysian catfish (Hybrid Clarias sp.)
Peck Loo Kiew,Mat Don Mashitah 한국응용생명화학회 2013 Applied Biological Chemistry (Appl Biol Chem) Vol.56 No.4
Acid soluble collagen (ASC) and pepsin soluble collagen (PSC) were isolated from the skin of hybrid Clarias sp. with the yields of 18.11±0.32 and 26.69±0.54% (wet weight basis), respectively. Both collagens were characterized as type I collagen, containing α1 and α2 chains. Presence of high molecular weight crosslinks were observed in the gel electrophoresis of both collagens. Fourier transform infrared spectra of both collagens were almost similar, suggesting that pepsin hydrolysis did not disrupt the triple helical structure. The amino acid analysis showed glycine was the most abundant, with 207/1000 and 223/1000 residues present in ASC and PSC, respectively. The amounts of imino acids were 185/1000 residues for both. Thermal denaturation temperatures were determined to be 31.5 and 31.0oC, respectively. Both collagens exhibited high solubility in acidic pH (1–5) and below 4% (w/v) NaCl concentration.