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McLean, VA, United States

Choi W.,Langley High School | Lee J.H.,Luminescent
Technical Proceedings of the 2013 NSTI Nanotechnology Conference and Expo, NSTI-Nanotech 2013 | Year: 2013

Rapid single nucleotide polymorphism (SNP) with 1, 1'-oxalylimidazole chemiluminescence (ODI-CL) detection was developed for the early diagnosis of human mad-cow disease. Mutated single strand DNA (ssDNA) sequence discovered from patients having human mad-cow disease rapidly hybridize with complementary probe conjugated with chemiluminescent dye. The hybridization between target ssDNA and complementary probe was dependent on four different variables such as pH, temperature, incubation time, and the type of nanoparticles (e.g., multi-walled carbon nanotubes, graphene oxide) capable of capturing mismatched ssDNAs and excess complementary probe. However, three different types of mismatched ssDNAs also slowly hybridize with complementary probe with the increase of incubation time. The problem was solved by using ODI-CL detection instead of fluorescence detection of conventional SNP because ODI-CL is about 100 times more sensitive than fluorescence. In other words, it was possible to reduce the interaction between mismatched ssDNAs and complementary probe with short incubation time (15 minutes) using highly sensitive ODI-CL detection. Based on the results, in conclusion, it is expected that SNP with ODI-CL can be applied as a cost-effective, rapid, and simple analytical method to diagnose and prognose various diseases. Source

Rosen R.,West Virginia University | Swiggum J.,West Virginia University | McLaughlin M.A.,West Virginia University | Lorimer D.R.,West Virginia University | And 67 more authors.
Astrophysical Journal | Year: 2013

We present the discovery and timing solutions of five new pulsars by students involved in the Pulsar Search Collaboratory, a NSF-funded joint program between the National Radio Astronomy Observatory and West Virginia University designed to excite and engage high-school students in Science, Technology, Engineering, and Mathematics (STEM) and related fields. We encourage students to pursue STEM fields by apprenticing them within a professional scientific community doing cutting edge research, specifically by teaching them to search for pulsars. The students are analyzing 300 hr of drift-scan survey data taken with the Green Bank Telescope at 350 MHz. These data cover 2876 deg2 of the sky. Over the course of five years, more than 700 students have inspected diagnostic plots through a web-based graphical interface designed for this project. The five pulsars discovered in the data have spin periods ranging from 3.1 ms to 4.8 s. Among the new discoveries are PSR J1926-1314, a long period, nulling pulsar; PSR J1821+0155, an isolated, partially recycled 33 ms pulsar; and PSR J1400-1438, a millisecond pulsar in a 9.5 day orbit whose companion is likely a white dwarf star. © 2013. The American Astronomical Society. All rights reserved. Source

Choi J.,Langley High School | Choi J.,Luminescent | Kim Y.-T.,Clemson University | Lee J.H.,Luminescent
Analyst | Year: 2010

A novel competitive 1,1′-oxalyldiimidazole (ODI) chemiluminescent enzyme immunoassay (CLEIA) was developed as a method for rapid and simple screening of melamine in milk. Fat existing in milk acts as an inhibitor in the competitive binding interaction of melamine and anti-melamine in the presence of melamine-conjugated horseradish peroxidase. Thus, the calibration curve and sensitivity of competitive ODI CLEIA for the quantification of melamine in fat free milk were wider and better than those in milk containing fat. However, a centrifuge is not a good method for removing the inhibitor because a portion of the melamine is also removed with the fat. The incubation time (20 min) for the competitive binding interaction of anti-melamine and melamine in 20% milk diluted with PBS buffer of pH 7.4 was longer than that (10 min) in 100% milk even though the sensitivity of the former was better than latter. The limit of detection (1.12 ppb) determined in rapid ODI CLEIA (dynamic range: 3.8-125 ppb) for the quantification of melamine in 20% milk not containing fat was lower than those (6.3 and 9.0 ppb) calculated in relatively time-consuming luminol CLEIA and enzyme-linked immunosorbent assay (ELISA). Also, we expect that ODI-CLEIA (dynamic range: 62.5-2000 ppb) capable of directly quantifying melamine in 100% milk without any pretreatment can be applied as a new and simple method for rapid screening of melamine in milk. © 2010 The Royal Society of Chemistry. Source

Spassova M.A.,U.S. Environmental Protection Agency | Miller D.J.,U.S. National Institutes of Health | Nikolov A.S.,Langley High School
Oxidative Medicine and Cellular Longevity | Year: 2015

We have developed a kinetic model to investigate how DNA repair processes and scavengers of reactive oxygen species (ROS) can affect the dose-response shape of prooxidant induced DNA damage. We used as an example chemical KBrO 3 which is activated by glutathione and forms reactive intermediates that directly interact with DNA to form 8-hydroxy-2-deoxyguanosine DNA adducts (8-OH-dG). The single strand breaks (SSB) that can result from failed base excision repair of these adducts were considered as an effect downstream from 8-OH-dG. We previously demonstrated that, in the presence of effective base excision repair, 8-OH-dG can exhibit threshold-like dose-response dependence, while the downstream SSB can still exhibit a linear dose-response. Here we demonstrate that this result holds for a variety of conditions, including low levels of GSH, the presence of additional SSB repair mechanisms, or a scavenger. It has been shown that melatonin, a terminal scavenger, inhibits KBrO 3 -caused oxidative damage. Our modeling revealed that sustained exposure to KBrO 3 can lead to fast scavenger exhaustion, in which case the dose-response shapes for both endpoints are not substantially affected. The results are important to consider when forming conclusions on a chemical's toxicity dose dependence based on the dose-response of early genotoxic events. © 2015 Maria A. Spassova et al. Source

Son Y.,Pusan National University | Nam J.-S.,Pusan National University | Jang M.-K.,Pusan National University | Jung I.-A.,Langley High School | And 2 more authors.
Bioscience, Biotechnology and Biochemistry | Year: 2013

In this study, we evaluated the antiobesity effects of Vigna nakashimae (VN) extract and elucidated the underlying mechanisms. VN extract suppressed adipocyte differentiation and significantly attenuated the expression of adipogenic genes in 3T3-L1 cells. It decreased the expression of peroxisome proliferatoractivated receptor γ (PPARγ) and its target genes in fully differentiated 3T3-L1 cells. Moreover, it enhanced the phosphorylation of AMP-activated protein kinase (AMPK) and acetyl CoA carboxylase (ACC), and increased the expression of fatty acid oxidation genes. In high-fat diet (HFD) fed mice, VN extract suppressed HFD-induced increases in body weight, epididymal fat tissue weight, and hepatic lipid levels, and decreased the plasma levels of triacylglycerols, fatty acid, total cholesterol, and inflammatory cytokines. Consistently with in vitro study results, VN extract prevented HFDinduced increases in the expression of PPARγ and its target genes, and restored the decrease in the phosphorylation of AMPK and ACC in epididymal fat and liver tissues. These findings suggest that Vigna nakashimae prevents obesity through suppression of PPARγ expression and activation of AMPK, and that it might be a useful dietary supplement for the prevention of obesity. Source

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