• Applied Chemistry for Engineering
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• v.31 no.5
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• pp.539-544
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• 2020

A three-dimensional (3D) porous polyaniline (PANI) film was fabricated by a combined photo-and soft-lithography technique based on a large-area nanopillar array, followed by a controlled chemical dilute polymerization. The as-obtained 3D PANI film consisted of hierarchically interconnected PANI nanofibers, resulting in a 3D hierarchical nanoweb film with a large surface and open porous structure. Using electrochemical measurements, the resulting 3D PANI film was demonstrated as a flexible pH sensor electrode, exhibiting a high sensitivity of 60.3 mV/pH, which is close to the ideal Nernstian behavior. In addition, the 3D PANI electrode showed a fast response time of 10 s, good repeatability, and good selectivity. When the 3D PANI electrode was measured under a mechanically bent state, the electrode exhibited a high sensitivity of 60.4 mV/pH, demonstrating flexible pH sensor performance.

• Asian Pacific Journal of Cancer Prevention
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• v.17 no.4
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• pp.2061-2066
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• 2016

Purpose: To determine the significance of P57KIP2 immunohistochemistry expression in the histopathological diagnosis of hydatidiform mole. Materials and Methods: Hydatidiform mole patients at King Chulalongkorn Memorial Hospital between January 1999 and December 2011 were recruited. Two gynecologic pathologists reviewed histopathologic slides to confirm diagnosis. Formalin-fixed, paraffin-embedded tissue sections were stained using a bstandard immunostaining system with monoclonal antibodies against P57KIP2 protein. Correlations among pathological features, immunohistochemical expression and clinical data were analyzed. Results: One hundred and twenty-seven hydatidiform mole patients were enrolled. After consensus review, 97 cases were diagnosed as complet (CHM) and 30 cases as partial (PHM). Discordance between the first and final H&E diagnoses was found in 19 cases (14.9%, k= 0.578). Significant pathological features to classify the type of hydatidiform mole are central cisterns, trophoblastic proliferation, trophoblastic atypia, two populations of villi, fetal vessels and scalloped borders. After performing immunohistochemistry for P57KIP2, 107 cases were P57KIP2 negative and 20 cases positive. Discordant diagnoses between final H&E diagnosis and P57KIP2 immunohistochemistry was identified in 12 cases (9.4%). Sensitivity of final H&E diagnosis for CHM was 89.7%; specificity was 95.0%. PHM sensitivity and specificity of final H&E diagnosis was 95.0% and 89.7%, respectively. Conclusions: Histopathological diagnosis alone has certain limitations in accurately defining types of hydatidiform mole; P57KIP2 immunohistochemistry is practical and can be a useful adjunct to histopathology to distinguish CHM from non-CHM.

• Corrosion Science and Technology
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• v.12 no.5
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• pp.220-226
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• 2013

The uncertainty in statistical noise resistance measurement was evaluated for a type 316 stainless steel in NaCl solutions at room temperature. Sensitivity coefficients were determined for measurands or variables such as NaCl concentration, pH, solution temperature, surface roughness, inert gas flow rate and bias potential amplitude. The coefficients were larger for the variables such as NaCl concentration, pH, inert gas flow rate and solution temperature, and they were the major factors increasing the combined standard uncertainty of noise resistance. However, the contribution to the uncertainty in noise resistance measurement from the above variables was remarkably low compared to that from repeated measurements of noise resistance, and thus, it is difficult to lower the uncertainty in noise resistance measurement significantly by lowering the uncertainties related with NaCl concentration, pH, inert gas flow rate and solution temperature. In addition, the uncertainty in noise resistance measurement was high amounting to 17.3 % of the mean, indicating that the reliability in measurement of noise resistance is low.

• Journal of Chest Surgery
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• v.43 no.4
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• pp.345-355
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• 2010

Background: Extracellular and intracellular pH ($pH_o$ and $pH_i$), which can be changed in various pathological conditions such as hypoxia, affects vascular contractility. To elucidate the mechanism to alter vascular contractility by pH, the effects of pH on reactivity to vasocontracting agents, intracellular $Ca^{2+}$ influx, and $Ca^{2+}$ sensitivity in vascular smooth muscle were examined. Material and Method: Isometric contractions in rat superior mesenteric arteries (SMA) were observed. Intracellular $Ca^{2+}$ concentration ($[Ca^{2+}]_i$) was recorded by microfluorometer using Fura-2/acetoxylmethyl ester in muscle cells. $pH_o$ was increased from 7.4 to 7.8 or decreased to 6.9 or 6.4. $pH_i$ was decreased by applying $NH_4^+$ or propionic acid or modulated by changing $pH_o$ after increasing membrane permeability using $\beta$-escin. Result: Decreases in $pH_o$ from 7.4 to 6.9 or 6.4 shifted concentration-response curve by norepinephrine (NE) or serotonin (SE) to the right and significantly increased half maximal effective concentration (EC50) to NE or SE. Increase in $pH_o$ from 7.4 to 7.8 shifted concentration-response curve by norepinephrine (NE) or serotonin (SE) to the left and significantly reduced EC50 to NE or SE. NE increased $[Ca^{2+}]_i$ in cultured smooth muscle cells from SMA and the increased $[Ca^{2+}]_i$ was reduced by decreases in $pH_o$. NE-induced contraction was inhibited by $NH_4^+$, whereas the resting tension was increased by $NH_4^+$ or propionic acid. When the cell membrane of SMA was permeabilized using ${\beta}$-escin, SMA was contracted by increasing extracellular $Ca^{2+}$ concentration from 0 to $10{\mu}M$ and the magnitude of contraction was decreased by a decrease in $pH_o$ and vice versa. Conclusion: From these results, it can be concluded that a decrease in $pH_o$ might inhibit vascular contraction by reducing the reactivity of vascular smooth muscle to vasoactive agents, $Ca^{2+}$ influx and the sensitivity of vascular smooth muscle to $Ca^{2+}$.

• Analytical Science and Technology
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• v.5 no.2
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• pp.177-184
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• 1992

A preparation method and response characteristics of a glucose sensor which consisted of pH-ISFET and glucose oxidase-immobilized membrane were investigated. The pH-ISFET glucose sensor was fabricated by immbilizing bovine serum albumin and glucose oxidase with glutaraldehyde on gate of the pH-ISFET. Effects of pH and concentration of working buffer and enzyme load on the pontentiometric response of the pH-ISFET glucose sensor were examined. Response characteristics for the determination of glucose in synthetic physiological saline solution(pH 7.4) were as follows. That is the concentration range of linear response, slope of linear response(sensitivity), and response time were $1.0{\times}10^{-4}{\sim}6.0{\times}10^{-3}M $, 4.1 mV/decade, and 12~15 min., respectively.

• Bulletin of the Korean Chemical Society
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• v.30 no.9
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• pp.2032-2038
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• 2009

The amount of phenol and NaOH for the colorimetric determination of ammonia in Korean standard methods (KSM) is found to be highly excessive compared to the standard methods of several other countries. The absorbance of indophenol formed by the Berthelot reaction for ammonia analysis was measured under the various reaction conditions classified in experiment groups 1, 2, 3, 4 and KSM and American standards methods (ASM), and the relationships between the absorbance of indophenol and concentration of ammonia were compared. The amount of phenol can be reduced to 10 g (current 25 g in KSM) and NaOH can be reduced to 1.76 g (current 11 g in KSM) for the preparation of 200 mL phenate solution, and the absorbance sensitivity increased. The concentration of the phenol and NaOH correlatively affect the pH of the solution, which is a critical variable in achieving the maximum sensitivity and rapid and stable color development.

• Korean Journal of Veterinary Research
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• v.44 no.3
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• pp.441-448
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• 2004

DNase activity in Haemonchus contortus reproductive tissue was characterized and compared to that in whole worm. DNase activity in reproductive tissue was detected throughout pHs 4-10 with high activity under acidic conditions. The activity was not inhibited by 10 mM EDTA at pH 5.0, but largely inhibited by pH 7.0. The activity produced DNA fragments with mixtures of 3'-hydroxyls (OH) and 3'- phosphates (P) at each pH. Three distinct DNase activities were identified and had $M_rs$ of 34, 36 and 38.5 kDa in zymograms, which were distinguished according to pH requirement and sensitivity to EDTA. Among them, the 36 kDa reproductive tissue DNase had predominant activity at pH 5.0, but very weak at pH 7.0, and this activity was not inhibited by EDTA at pH 5.0. These characteristics of the 36 kDa reproductive tissue DNase resemble those of classic acidic DNases. In contrast, 36 kDa whole worm DNase activity had high activity at both pH 5.0 and 7.0. While the 36 kDa DNase activity at pH 5.0 was similar in both reproductive tissue and whole worm samples, the activity at pH 7.0 was predominantly detected in whole worm sample. This suggests that the 36 kDa whole worm DNase at pH 5.0 differs from that at pH 7.0. Thus, results indicate that the EDTA-insensitive 36 kDa DNase at pH 5.0 is specific for H. contortus reproductive tissue.

• BMB Reports
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• v.42 no.4
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• pp.223-226
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• 2009

We measured the pH-induced spectral changes of yeast iso-1-cytochrome c on silver nanoparticle surfaces using surface-enhanced resonance Raman scattering (SERRS) at 457.9 nm. At a pH of ~3, the Met80 ligand in yeast iso-1-cytochrome c is assumed to dissociate, leading to a marked conformational change as evidenced by the vibrational spectral shifts. The Soret band at ~410 nm in the UV-Vis spectrum shifted to ~396 nm at pH~3, indicating a transition from a low spin state to a high spin state from a weak interaction with a water molecule. Thus, SERRS spectroscopy can measure the pH-induced denaturalization of cyt c adsorbed on metal nanoparticle surfaces at a lower concentration with a better sensitivity than ordinary resonance Raman spectroscopy.

• Clinical and Experimental Reproductive Medicine
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• v.3 no.1
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• pp.13-19
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• 1976

Serum levels of human placental lactogen have been measured by hemagglutination-inhibition reaction in 67 normal pregnant state and in 15 postpartum 24 hour state, HAIR is less sensitive and reliable method than radioimmunoassay, but simple, rapid, less expensive and fairly accurate, so it is more helpful in screening of large antenatal population with or without high risk complications. 1) Sensitivity of HPL-HAIR test kit was $0.1{\mu}g$/ml of H.P.L. serum level and had no cross reaction to HCG or male serum or non-pregenant female or newborn infant, 2) H.P.L. value was around $2{\mu}g$/ml until 24th week of pregnancy and rose to $6{\sim}8$ ${\mu}g$/ml continuously until about 36th week of pregnancy and then slightly decreased or stationary. 3) H.P.L. value in postpartum 24 hour state was undetectable. 4) There was poor correlation between maternal serum H.P.L. value at term and baby weight.

• Journal of the Korean Chemical Society
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• v.36 no.6
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• pp.864-871
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• 1992

A preparation method and response characteristics of a urea sensor which consisted of pH-ISFET and urease-immobilized membrane were investigated. The pH-ISFET urea sensor was fabricated by immobilizing BSA and urease with glutaraldehyde on gate of the pH-ISFET. Effects of pH and concentration of working buffer and enzyme load on the pontentiometric response of the pH-ISFET urea sensor were examined. Response characteristics for the determination of urea in synthetic physiological saline solution (pH 7.4) were as follows. That is, the concentration range of linear response, slope of linear response (sensitivity), and response time were 5.0 ${\times}$ $10^{-4}$ ${\sim}$ 5.0 ${\times}$ $10^{-2}$M, 31.6 mV/decade and 4${\sim}$10 min, respectively.