• Nano
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• v.13 no.11
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• pp.1850131.1-1850131.19
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• 2018

In this paper, an electrochemical sensor for epinephrine (EP), a neurotransmitter was developed by anchoring molecularly imprinted polymeric matrix (MIP) on the surface of gold-coated quartz crystal electrode of electrochemical quartz crystal microbalance (EQCM) using starch nanoparticles (Starch NP) - reduced graphene oxide (RGO) nanocomposite as polymeric format for the first time. Use of EP in therapeutic treatment requires proper dose and route of administration. Proper follow-up of neurological disorders and timely diagnosis of them has been found to depend on EP level. The MIP sensor was developed by electrodeposition of starch NP-RGO composite on EQCM electrode in presence of template EP. As the imprinted sites are located on the surface, high specific surface area enables good accessibility and high binding affinity to template molecule. Differential pulse voltammetry (DPV) and piezoelectrogravimmetry were used for monitoring binding/release, rebinding of template to imprinted cavities. MIP-coated EQCM electrode were characterized by contact angle measurements, AFM images, piezoelectric responses including viscoelasticity of imprinted films, and other voltammetric measurements including direct (DPV) and indirect (using a redox probe) measurements. Selectivity was assessed by imprinting factor (IF) as high as 3.26 (DPV) and 3.88 (EQCM). Sensor was rigorously checked for selectivity in presence of other structurally close analogues, real matrix (blood plasma), reproducibility, repeatability, etc. Under optimized conditions, the EQCM-MIP sensor showed linear dynamic ranges ($1-10{\mu}M$). The limit of detection 40 ppb (DPV) and 290 ppb (EQCM) was achieved without any cross reactivity and matrix effect indicating high sensitivity and selectivity for EP. Hence, an eco-friendly MIP-sensor with high sensitivity and good selectivity was fabricated which could be applied in "real" matrices in a facile manner.

• Journal of Ginseng Research
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• v.43 no.1
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• pp.1-9
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• 2019

Background: Korean ginseng is an important cash crop in Asian countries. However, plant yield is reduced by pathogens. Among the Ilyonectria radicicola-species complex, I. mors-panacis is responsible for root-rot and replant failure of ginseng in Asia. The development of new methods to reveal the existence of the pathogen before cultivation is started is essential. Therefore, a quantitative real-time polymerase chain reaction method was developed to detect and quantify the pathogen in ginseng soils. Methods: In this study, a species-specific histone H3 primer set was developed for the quantification of I. mors-panacis. The primer set was used on DNA from other microbes to evaluate its sensitivity and selectivity for I. mors-panacis DNA. Sterilized soil samples artificially infected with the pathogen at different concentrations were used to evaluate the ability of the primer set to detect the pathogen population in the soil DNA. Finally, the pathogen was quantified in many natural soil samples. Results: The designed primer set was found to be sensitive and selective for I. mors-panacis DNA. In artificially infected sterilized soil samples, using quantitative real-time polymerase chain reaction the estimated amount of template was positively correlated with the pathogen concentration in soil samples ($R^2=0.95$), disease severity index ($R^2=0.99$), and colony-forming units ($R^2=0.87$). In natural soils, the pathogen was recorded in most fields producing bad yields at a range of $5.82{\pm}2.35pg/g$ to $892.34{\pm}103.70pg/g$ of soil. Conclusion: According to these results, the proposed primer set is applicable for estimating soil quality before ginseng cultivation. This will contribute to disease management and crop protection in the future.

• Journal of Preventive Medicine and Public Health
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• v.52 no.3
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• pp.179-187
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• 2019

Objectives: In the USA, certain races and ethnicities have a disproportionately higher gastric cancer burden. Selective screening might allow for earlier detection and curative resection. Among a USA-based multiracial and ethnic cohort diagnosed with non-cardia gastric cancer (NCGC), we aimed to identify factors associated with curable stage disease at diagnosis. Methods: We retrospectively identified endoscopically diagnosed and histologically confirmed cases of NCGC at Mount Sinai Hospital in New York City. Demographic, clinical, endoscopic and histologic factors, as well as grade/stage of NCGC at diagnosis were documented. The primary outcome was the frequency of curable-stage NCGC (stage 0-1a) at diagnosis in patients with versus without an endoscopy negative for malignancy prior to their index exam diagnosing NCGC. Additional factors associated with curable-stage disease at diagnosis were determined. Results: A total of 103 racially and ethnically diverse patients were included. Nearly 38% of NCGC were stage 0-Ia, 34% stage Ib-III, and 20.3% stage IV at diagnosis. A significantly higher frequency of NCGC was diagnosed in curable stages among patients who had undergone an endoscopy that was negative for malignancy prior to their index endoscopy that diagnosed NCGC, compared to patients without a negative endoscopy prior to their index exam (69.6% vs. 28.6%, p=0.003). A prior negative endoscopy was associated with 94.0% higher likelihood of diagnosing curable-stage NCGC (p=0.003). No other factors analyzed were associated with curablestage NCGC at diagnosis. Conclusions: Endoscopic screening and surveillance in select high-risk populations might increase diagnoses of curable-stage NCGC. These findings warrant confirmation in larger, prospective studies.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.13 no.6
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• pp.477-482
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• 2020

The human visual cortex has the characteristic that reacts sensitively to stimuli with special directional or temporal frequency changes while it is insensitive to selective stimuli of spatial phases. In this paper we implemented the model of complex cell using an image estimation iterative algorithm by Gabor wavelet transform. The performance of implemented model evaluated the consistency between the physiological experimental results in related papers. The implemented model is limited in the complete model of the receptive field in the retina where simple cells and complex cells are distributed together. But the implemented model express the reaction of the complex cells from the point of view of the detection of corners and edges.

• Applied Chemistry for Engineering
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• v.32 no.4
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• pp.456-460
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• 2021

A potentiometric sodium-ion (Na⁺) sensor was prepared using a screen-printing process with carbon and silver inks. The two-electrode configuration of the sensor resulted in potential differences in Na⁺ solutions according to Nernstian equation. The obtained Na⁺-sensor exhibited an ideal Nernstian sensitivity, fast response time, and low limit of detection. The Nernstian response was stable when the sensor was tested for repeatability and long-term durability. The Na⁺-selective membrane coated onto the carbon electrode selectively passed sodium ions against interfering ions, indicating an excellent selectivity. The portable Na⁺-sensor was finally fabricated using a printed circuit system, demonstrating the successful measurements of Na⁺ concentrations in various real samples.

• Animal Bioscience
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• v.36 no.7
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• pp.1120-1129
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• 2023

Objective: This study aimed to determine the protective efficacy of Buddha's Temple (BT) extract against tert-butyl hydroperoxide (t-BHP)-induced oxidative stress in Gallus gallus chicken embryo fibroblast cell line (DF-1) and its effects on the cell lipid metabolism. Methods: In this experimental study, Gallus gallus DF-1 fibroblast cells were pretreated with BT 10^-7 for 24 hours, followed by their six-hour exposure to t-BHP (100 μM). Water-soluble tetrazolium salt-8 (WST-8) assays were performed, and the growth curve was computed. The intracellular gene expression changes caused by BT extract were confirmed through quantitative polymerase chain reaction (qPCR). Flow cytometry, oil red O staining experiment, and thin-layer chromatography were performed for the detection of intracellular metabolic mechanism changes. Results: The WST-8 assay results showed that the BT pretreatment of Gallus gallus DF-1 fibroblast cell increased their cell survival rate by 1.08%±0.04%, decreased the reactive oxygen species (ROS) level by 0.93%±0.12% even after exposure to oxidants, and stabilized mitochondrial activity by 1.37%±0.36%. In addition, qPCR results confirmed that the gene expression levels of tumor necrosis factor α (TNFα), TIR domain-containing adapter inducing IFN-beta (TICAM1), and glucose-regulated protein 78 (GRP78) were regulated, which contributed to cell stabilization. Thin-layer chromatography and oil red O analyses showed a clear decrease in the contents of lipid metabolites such as triacylglycerol and free fatty acids. Conclusion: In this study, we confirmed that the examined BT extract exerted selective protective effects on Gallus gallus DF-1 fibroblast cells against cell damage caused by t-BHP, which is a strong oxidative inducer. Furthermore, we established that this extract significantly reduced the intracellular ROS accumulation due to oxidative stress, which contributes to an increase in poultry production and higher incomes.

• Advances in nano research
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• v.14 no.4
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• pp.313-327
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• 2023

Zinc metal organic framework (MOF_Zn)-loaded goad nanoparticles (AuNPs) sol (Au@MOF_Zn), which was characterized by TEM, Mapping, FTIR, XRD, and molecular spectrum, was prepared conveniently by solvothermal method. The results indicated that Au@MOF_Zn had a very strong catalytic effect with the nanoreaction of AuNPs formation between sodium oxalate (SO) and HAuCl4. AuNPs in the new indicator reaction had a strong resonance Rayleigh scattering (RRS) signal at 370 nm. The indicator AuNPs generated by this reaction, which had the most intense surface enhanced Raman scattering (SERS) peak at 1621 cm -1. The new SERS/RRS indicator reaction in combination with specific aptamer (Apt) to fabricate a sensitive and selective Au@MOF_Zn catalytic amplification-aptamer SERS/RRS assay platform for carbendazim (CBZ), with SERS/RRS linear range of 0.025-0.5 ng/mL. The detection limit was 0.02 ng/mL. Similarly, this assay platform has been also utilized to detect oxytetracycline (OTC) and profenofos (PF).

• Composites Research
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• v.36 no.3
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• pp.217-223
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• 2023

In this work, the preparation and its oil adsorption behavior of polyacrylonitrile-based carbon nanofiber sponge were investigated. The prepared carbon sponges showed excellent selective oil adsorption in the mixture of water and oil, and the adsorption capacity of reused carbon nanofiber sponge was also investigated. Further, carbon nanofiber sponge adsorbent with internally structured channel showed fast oil adsorption behavior due to a capillary phenomenon. After use, sponge adsorbent was heat-treated at 800℃ under N² and studied the possibility of a sensor for electrochemical detection of 4-aminophenol.

• Journal of the Korea Institute of Military Science and Technology
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• v.26 no.3
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• pp.246-251
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• 2023

RADAR(Radio Detection and Ranging) is an important system for surveillance and reconnaissance by detecting a reflected signal which obtains the range from the radar to the target, and the velocity of the target. The magnitude of the reflected signal varies due to the radar cross section of the target, characteristic of the transmission and reception antenna, distance between the radar and the target, and power and wavelength of the transmitted signal. Thus, the RCS is the important characteristic of the target to determine if the target can be observed by the RADAR system. It is based on the material and shape of the target. We have measured the reflection signal of a simple square-shaped (20 × 20 cm) target made of a new material, a gallium-based liquid metal alloy and compared that of well-known metals including copper, aluminum. The magnitude of reflected signal of the aluminum target was the largest and it was 2.4 times larger than that of the liquid metal target. We also investigated the effect of the shape by measuring reflectance of the F-22 3D model(~1/95 ratio) target covered with/without copper, aluminium, and liquid metal. The largest magnitude of the reflected signal measured from side-view with the copper-covered F-22 model was 2.6 times greater than that of liquid metal. The reflectance study of the liquid metal would be helpful for liquid metal-based frequency selective surface or metamaterials.

• Analytical Science and Technology
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• v.20 no.2
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• pp.164-169
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• 2007

A selective analytical method of LC/MS/MS has been applied to determine the levels of acrylamide in food products. Food samples were 17 including 6 potato chips, and 11 french fries. The analysis of food samples includes extraction with DDDW, clean-up using C18 and mixed ion exchange SPE cartridges and detection by liquid chromatography tandem mass spectrometry. The mobile phase was a mixture of 0.1 % acetic acid and 0.5 % methanol in water. The target ions were identified and determined by ESI mass spectrometer. The overall recoveries were ranged from 91 % to 101 % and the limit of quantitation was $10{\mu}g/kg$. Depending on food kinds, the levels of acrylamide were variable and the average was 0.71 mg/kg for potato chips, and 0.34 mg/kg for french fries.