• Applied Chemistry for Engineering
• /
• v.16 no.5
• /
• pp.689-692
• /
• 2005

In order to improve the electrochemical performances of Li-ion batteries when spinel $LiMn_2O_4$ is employed as a cathode active material, binary conductive agents were prepared using two different particle-sized carbons like Super P Black and $Vulcan^{(R)}$ XC-72R. The electrochemical performances of the $LiMn_2O_4$ cell system using binary conductive agents were evaluated in terms of specific charge and discharge capacities and cycle life. The cell with binary conductive agent in the 3:7 weight ratios of Super P Black and $Vulcan^{(R)}$ XC-72R showed better electrochemical performances due to the proper combination of ionic diffusion rate and electric contact.

• Polymer(Korea)
• /
• v.36 no.6
• /
• pp.739-744
• /
• 2012

In this work, we prepared the carbons from synthesized styrene-acrylonitrile carbon precursor. The prepared carbons were chemically activated, and then the activated SAN-based carbons were named as A-SANs. The activations were carried out at different temperatures to investigate the effect of activation temperature on the surface and electrochemical properties of the activated SAN-based carbons for using as an electrode of electric double layer capacitors (EDLC). The characteristics of A-SAN were determined by X-ray diffraction (XRD), scanning electron microscopy (SEM), surface area and pore size analysis. Also, the electrochemical behaviors were observed by cyclic voltammetry and galvanostatic charge-discharge method. From the results, the A-SAN 700 showed excellent electrochemical property and the highest specific capacitance, but these properties decreased when the activation temperature was above $700^{\circ}C$. This is due to the fact that the activation at a temperature over $700^{\circ}C$ causes deformation of micropore structures.

• Journal of Gastric Cancer
• /
• v.20 no.3
• /
• pp.267-276
• /
• 2020

Purpose: The American College of Surgeons National Surgical Quality Improvement Program (ACS NSQIP) risk calculator is useful in predicting postoperative adverse events. However, its accuracy in specific disorders is unclear. We validated the ACS NSQIP risk calculator in patients with gastric cancer undergoing curative laparoscopic surgery. Materials and Methods: We included 207 consecutive early gastric cancer patients who underwent laparoscopic gastrectomy between January 2018 and January 2019. The preoperative characteristics and risks of the patients were reviewed and entered into the ACS NSQIP calculator. The estimated risks of postoperative outcomes were compared with the observed outcomes using C-statistics and Brier scores. Results: Most of the patients underwent distal gastrectomy with Roux-en-Y reconstruction (74.4%). We did not observe any cases of mortality, venous thromboembolism, urinary tract infection, renal failure, or cardiac complications. The other outcomes assessed were complications such as pneumonia, surgical site infections, any complications requiring re-operation or hospital readmission, the rates of discharge to nursing homes/rehabilitation centers, and the length of stay. All C-statistics were <0 and the highest was for pneumonia (0.65; 95% confidence interval: 0.58-0.71). Brier scores ranged from 0.01 for pneumonia to 0.155 for other complications. Overall, the risk calculator was inconsistent in predicting the outcomes. Conclusions: The ACS NSQIP surgical risk calculator showed low predictive ability for postoperative adverse events after laparoscopic gastrectomy for patients with early gastric cancer. Further research to adjust the risk calculator for these patients may improve its predictive ability.

• Bulletin of the Korean Chemical Society
• /
• v.35 no.5
• /
• pp.1349-1355
• /
• 2014

A three-dimensional (3D) $Co_3O_4$/mildly oxidized multiwalled carbon nanotubes (moCNTs)/reduced mildly oxidized graphene oxide (rmGO) ternary composite was prepared via a simple and green hydrolysishydrothermal approach by mixing $Co(Ac)_2{\cdot}4H_2O$ with moCNTs and mGO suspension in mixed ethanol/$H_2O$. As characterized by scanning electron microscopy and transmission electron microscopy, $Co_3O_4$ nanoparticles with size of 20-100 nm and moCNTs are effectively anchored in mGO. Cyclic voltammetry and galvanostatic charge-discharge measurements were adopted to investigate the electrochemical properties of $Co_3O_4$/moCNTs/rmGO ternary composite in 6 M KOH solution. In a potential window of 0-0.6 V vs. Hg/HgO, the composite delivers an initial specific capacitance of 492 $Fg^{-1}$ at 0.5 $Ag^{-1}$ and the capacitance remains 592 $Fg^{-1}$ after 2000 cycles, while the pure $Co_3O_4$ shows obviously capacitance fading, indicating that rmGO and moCNTs greatly enhance the electrochemical performance of $Co_3O_4$.

• Clinical and Experimental Pediatrics
• /
• v.61 no.11
• /
• pp.348-354
• /
• 2018

Purpose: The purpose of this study was to identify the causes, symptoms, and complications of hypoproteinemia to prevent hypoproteinemia and provide appropriate treatment to children with atopic dermatitis. Methods: Children diagnosed with atopic dermatitis with hypoproteinemia and/or hypoalbuminemia were retrospectively reviewed. The patients' medical records, including family history, weight, symptoms, treatment, complications, and laboratory test results for allergies and skin cultures, were examined. Results: Twenty-six patients (24 boys) were enrolled. Seven cases had growth retardation; 7, keratoconjunctivitis; 6, aural discharges; 5, eczema herpeticum; 4, gastrointestinal tract symptoms; and 2, developmental delays. In 21 cases, topical steroids were not used. According to the blood test results, the median values of each parameter were elevated: total IgE, 1,864 U/mL; egg white-specific IgE, $76.5kU_A/L$; milk IgE, $20.5kU_A/L$; peanut IgE, $30kU_A/L$; eosinophil count, $5,810/{\mu}L$; eosinophil cationic protein, $93.45{\mu}g/L$; and platelet count, $666.5{\times}10^3/{\mu}L$. Serum albumin and total protein levels decreased to 2.7 g/dL and 4.25 g/dL, respectively. Regarding electrolyte abnormality, 10 patients had hyponatremia, and 12, hyperkalemia. Systemic antibiotics were used to treat all cases, and an antiviral agent was used in 12 patients. Electrolyte correction was performed in 8 patients. Conclusion: Hypoproteinemia accompanying atopic dermatitis is common in infants younger than 1 year and may occur because of topical steroid treatment continuously being declined or because of eczema herpeticum. It may be accompanied by growth retardation, keratoconjunctivitis, aural discharge, and eczema herpeticum and can be managed through skin care and topical steroid application without intravenous albumin infusion.

• Journal of Environmental Health Sciences
• /
• v.41 no.5
• /
• pp.305-313
• /
• 2015

Objectives: The objective of this study is to identify toxicants causing acute toxicity in effluents from the aluminum rolling industry that violate the discharge limits in Korea. Methods: Whole effluent toxicity tests (WET) were conducted on effluent discharged from the aluminum rolling industry following the US EPA WET test methods. We collected effluent samples three times and evaluated acute toxicity by using Daphnia magna. We employed toxicity identification evaluation (TIE) procedures to identify toxicants causing toxicity in the effluent. Results: No specific chemical groups were identified in the seven different manipulations applied to the of wastewater effluent samples showing 1.3 toxic units (TU) according to the TIE phase I procedures. Water quality parameters for water hardness, electric conductivity and heavy metals (Mn) were 4,322 mg/l as $CaCO_3$, 11.39 mS/cm, and $5,551{\mu}g/l$, respectively. Considering water hardness and reference toxicity, high concentrations of Mn can be disqualified from the causative toxicants. Consequently, high ionic concentrations of $Na^+$(1,648 mg/l), $Ca^{2+}$(1,048 mg/l), $Mg^{2+}$(1,428 mg/l) and $SO_4{^{2-}}$(7,472 mg/l) were identified to be causative toxicants. Water hardness and electric conductivity exceed the $EC_{50}$ value obtained by biological toxicity tests using Daphnia magna. Conclusion: According to TIE procedures, high salt concentration is determined to be a major toxicant in the effluent of agro-industrial wastewater treatment plants receiving wastewater from the aluminum rolling industry.

• Applied Chemistry for Engineering
• /
• v.27 no.4
• /
• pp.439-443
• /
• 2016

In this report, $MnO_2$ nanoparticle-deposited functionalized graphene sheets were prepared and their superior electrochemical performances were demonstrated by cyclic voltammetry, galvanostatic charge-discharge, and impedance analysis. Ionic liquids were employed to functionalize the surface of reduced graphene oxides (RGOs), leading to prevention of the aggregation of RGO sheets and abundant growth sites for deposition of $MnO_2$ nanoparticles. As-prepared $MnO_2/RGO$ nanocomposites were characterized using scanning electron microscope, transition electron microscope, X-ray photoelectron spectroscopy, and X-ray diffraction. Electrochemical properties of $MnO_2/RGO$ electrode were evaluated using $Na_2SO_4$ electrolyte under a three-electrode system. The $MnO_2/RGO$ electrode showed a high specific capacitance (251 F/g), a high rate capability (80.5% retention), and long-term stability (93.6% retention).

• Restorative Dentistry and Endodontics
• /
• v.27 no.6
• /
• pp.587-599
• /
• 2002

Extracellular single unit recordings were made from the ventral posteromedial thalamic (VPM) nociceptive neurons to determine mechanoreceptive field (RF) and response properties. A total of 44 VPM thalamic nociceptive neurons were isolated from rats anesthetized with urethane-chloralose. Based on responses to various mechanical stimuli including touch, pressure and pinch applied to the RF, 32 of 44 neurons were classified as nociceptive specific (NS) neuron. The other 12 neurons, classified as wide dynamic range (WDR), showed a graded response to increasingly intense stimuli, with a maximum discharge to noxious pinch. The VPM nociceptive neurons showed various spontaneous activity ranged from 0-6 Hz. They were located throughout the VPM, and had an contralateral RF including mainly intraoral (and perioral) regions. The RF size was relatively small, and very few neurons had a receptive field involving 3 trigeminal divisions. The NS neurons activated only by pressure and pinch stimuli had high mechanical thresholds compared to WDR neurons activated also by touch stimuli. The VPM nociceptive neurons were tested with suprathershold graded mechanical stimuli. Most of 21 NS and 8 WDR neurons showed a progressive increase in number of spikes as mechanical stimulus intensity was increased. In some neurons, the responses reached a peak before the highest intensity was given. Application of 5 mM $CoCl_2{\;}(10{\;}{\mu}\ell)$ solution to the trigeminal subnucleus caudalis did not produce any significant changes in the spontaneous activity, RF size, mechanical threshold, and response to suprathreshold mechanical stimuli of 9 VPM nociceptive neurons tested. 17 of 33 VPM nociceptive neurons responded to noxious heat as well as noxious mechanical stimuli applied to their RF. Application of the mustard oil, a small-fiber excitant and inflammatory irritant, to the right maxillary first molar tooth pulp induced an immediate but short-lasting neuronal discharges upto approximately 4 min in 16 of 42 VPM nociceptive neurons. These results suggest that VPM thalamic nucleus may contribute to the sensory discriminative aspect of orofacial nociception.

• Journal of the Korean Crystal Growth and Crystal Technology
• /
• v.30 no.4
• /
• pp.123-130
• /
• 2020

Nano seed incorporated in micro-sized 4BS (Tetrabasic lead Sulfate) seed was applied to the positive electrode active material and compared with Nano 4BS seed (NS). The dispersion of NS decreased due to the aggregation phenomenon, while the nano seed incorporated in micro-sized 4BS seed (INS) could confirm excellent dispersion. As the content of INS increased, the particle size of the active material became small and constant, which was confirmed through SEM and particle size analysis. The specific surface area for the reaction was increased and the high-rate discharge and lifetime characteristics were improved. In order to confirm the variation in particle size distribution in the plate manufacturing process, internal resistance and voltage were measured for 200 AGM lead-acid batteries, and it was confirmed that batteries quality variation decreased.

• Journal of the Korean Electrochemical Society
• /
• v.5 no.1
• /
• pp.1-6
• /
• 2002

Silver doped vanadium pentoxides with a doping ratio Ag/V ranging from 0.03 to 0.11 were synthesized by sol-gel process, and $Li/Ag_xV_2O_5$ cell was investigated by the electrochemical methods. It appears to be amorphous layered material and entangled fibrous textures has been grown to form anisotropic corrugated fibrils. NMR measurements revealed that several different kinds of $Li^+$ ions exist in the lithium intercalated xerogel electrodes and the average cell potential was about 3.0V vs. $Li/Li^+$. The cell capacity of the silver doped $Ag_xV_2O_5$ xerogel cathodes was more than 359 mAh/g at discharge current 10mA/g and cycle efficiency $94\%$ was achieved.