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Maghsoud H.,South Carolina Governors School for Science and Mathematics | Weiss A.,Winthrop University | Smith J.P.S.,Winthrop University | Litvaitis M.K.,University of New Hampshire | Fegley S.R.,North Carolina A&T State University
Invertebrate Biology | Year: 2014

Analysis of the meiofaunal food web is hampered because few prey have features that persist long enough in a predator's digestive tract to allow identification to species. Hence, at least for platyhelminth predators, direct observations of prey preference are almost nonexistent, and where they occur, prey identification is often limited to the phylum level. Studies using an in vitro approach are rare because they are extremely time-consuming and are subject to the criticism that predators removed from their natural environment may exhibit altered behaviors. Although PCR-based approaches have achieved wide application in food-web analysis, their application to meiofaunal flatworms suffers from a number of limitations. Most importantly, the microscopic size of both the predator and prey does not allow for removal of prey material from the digestive tract of the predator, and thus the challenge is to amplify prey sequences in the presence of large quantities of predator sequence. Here, we report on the successful use of prey-taxon-specific primers in diagnostic PCR to identify, to species level, specific prey items of 13 species of meiofaunal flatworms. Extension of this method will allow, for the first time, the development of a species-level understanding of trophic interactions among the meiofauna. © 2014, The American Microscopical Society, Inc.

Bateman H.R.,University of South Carolina | Liang Q.,University of South Carolina | Liang Q.,Nanjing University | Fan D.,University of South Carolina | And 2 more authors.
PLoS ONE | Year: 2013

Sparstolonin B (SsnB) is a novel bioactive compound isolated from Sparganium stoloniferum, an herb historically used in Traditional Chinese Medicine as an anti-tumor agent. Angiogenesis, the process of new capillary formation from existing blood vessels, is dysregulated in many pathological disorders, including diabetic retinopathy, tumor growth, and atherosclerosis. In functional assays, SsnB inhibited endothelial cell tube formation (Matrigel method) and cell migration (Transwell method) in a dose-dependent manner. Microarray experiments with human umbilical vein endothelial cells (HUVECs) and human coronary artery endothelial cells (HCAECs) demonstrated differential expression of several hundred genes in response to SsnB exposure (916 and 356 genes, respectively, with fold change ≥2, p<0.05, unpaired t-test). Microarray data from both cell types showed significant overlap, including genes associated with cell proliferation and cell cycle. Flow cytometric cell cycle analysis of HUVECs treated with SsnB showed an increase of cells in the G1 phase and a decrease of cells in the S phase. Cyclin E2 (CCNE2) and Cell division cycle 6 (CDC6) are regulatory proteins that control cell cycle progression through the G1/S checkpoint. Both CCNE2 and CDC6 were downregulated in the microarray data. Real Time quantitative PCR confirmed that gene expression of CCNE2 and CDC6 in HUVECs was downregulated after SsnB exposure, to 64% and 35% of controls, respectively. The data suggest that SsnB may exert its anti-angiogenic properties in part by downregulating CCNE2 and CDC6, halting progression through the G1/S checkpoint. In the chick chorioallantoic membrane (CAM) assay, SsnB caused significant reduction in capillary length and branching number relative to the vehicle control group. Overall, SsnB caused a significant reduction in angiogenesis (ANOVA, p<0.05), demonstrating its ex vivo efficacy. © 2013 Bateman et al.

Tong J.,China University of Mining and Technology | Tong J.,University of South Carolina | Bills Z.,South Carolina Governors School for Science and Mathematics | Zhang L.,University of South Carolina | And 3 more authors.
Ceramic Transactions | Year: 2015

A new kind of duel-phase electrochemical membrane comprised of a Gd-doped CeO2 (GDC) modified by Al2O3 and a carbonate has been investigated in this study for stable CO2 separation. A porous GDC was used as the membrane matrix and oxide-ion conductor, and a (LiNa)2CO3 eutectic molten carbonate (MC) was used as the carbonate-ion conductor. 5 mol% Al2O3 was added into GDC as a modifier to improve me wettability of GDC with MC so that the retention of MC and subsequently the flux stability can be further enhanced. A CO2 flux density as high as 0.23 ml·min-1· cm-2 at 650°C was achieved with a feeding gas of 50% N2-50%CO2. The CO2 flux measured under a simulated flue gas containing 10% CO2 at 650°C was 0.12-0.15 ml·min-1cm-2 and stable for 100 hours. O2 was also observed to permeate with CO2 through the membrane, but in a smaller fraction. A parallel mechanism for the concurrent O2-transport was proposed. Copyright © 2015 by The American Ceramic Society. All rights reserved.

Xu N.,University of South Carolina | Xu N.,University of Science and Technology Beijing | Li X.,University of South Carolina | Franks M.A.,South Carolina Governors School for Science and Mathematics | And 2 more authors.
Journal of Membrane Science | Year: 2012

One of the major concerns of consuming fossil fuels to produce useful form of energy is the emission of CO 2, a greenhouse gas that can cause climate change and ultimately threaten the survival of humanity. Controlling CO 2-emission is an urgent but only practical solution to stabilize CO 2 concentration in the atmosphere. In this paper, we report our effort to capture CO 2 from a simulated flue gas by utilizing a dual-phase mixed carbonate-ion and electron conducting membrane, namely molten carbonate and silver. The obtained CO 2 and O 2 flux densities are the highest among the published metal-molten carbonate systems and relatively stable over 80-h period. The measured CO 2 and O 2 flux densities not only exhibit similar activation energy but also have the ratio of 2:1, favorably confirming the surface electrochemical reaction of CO 2+1/2O 2+2e'=CO 3 2-. These results demonstrate the Ag-MC dual-phase composite as a promising high-flux membrane for high-temperature electrochemical CO 2 separation from flue gas with high selectivity. © 2012 Elsevier B.V.

Maximov V.D.,Clemson University | Reukov V.V.,Clemson University | Barry J.N.,Clemson University | Cochrane C.,South Carolina Governors School for Science and Mathematics | Vertegel A.A.,Clemson University
Nanotechnology | Year: 2010

Hyperlipidemia, a condition associated with atherosclerosis, can develop because of the lack of low density lipoprotein (LDL) receptors in hepatocytes. Since injected polymeric nanoparticles are quickly taken up by the liver Kupffer cells, we hypothesize that it is possible to enhance LDL delivery to the liver through the use of LDL-absorbing nanoparticles. Here, we demonstrate the feasibility of the proposed approach in vitro. We used biodegradable and biocompatible polylactide nanoparticles (∼100nm in diameter) with covalently attached apolipoprotein B100 antibody to adsorb LDLs at physiologically relevant concentrations. We showed that up to sixfold decreases of LDL levels can be achieved in vitro upon treatment of LDL suspensions (500mgdl -1) with anti-apoB100-nanoparticle conjugates. The study of the uptake of the antibody-nanoparticle-LDL complexes by cells was performed using a mouse macrophage cell line (RAW 264.7) as a model for liver Kupffer cells. We found that macrophages can quickly take up antibody-nanoparticle-LDL complexes and digest them within 24h. No evidence of cytotoxicity was observed for the experimental conditions used in this study. © 2010 IOP Publishing Ltd.

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