Reduced graphene oxide (rGO) is one of the promising sensing elements for high-performance chemoresistive sensors because of its remarkable advantages such as high surface-to-volume ratio, ...outstanding transparency, and flexibility. In addition, the defects on the surface of rGO, including oxygen functional groups, can act as active sites for interaction with gaseous molecules. However, the major drawback of rGO-based sensors is the extremely sluggish and irreversible recovery to the initial state after a sensing event, which makes them incapable of producing repeatable and reliable sensing signals. Here, we show that pristine GO can be used as the active sensing material with reversible and high response to NO sub(2) at room temperature. First-principles calculations, in conjunction with experimental results, reveal the critical role of hydroxyl groups rather than epoxy groups in changing metallic graphene to the semiconducting GO. We show that the adaptive motions of the hydroxyl groups, that is, the rotation of these groups for the adsorption of NO sub(2) molecules and relaxation to the original states during the desorption of NO sub(2) molecules, are responsible for the fast and reversible NO sub(2) sensing behavior of GO. Our work paves the way for realizing high-response, reversible graphene-based room-temperature chemoresistive sensors for further functional convergence.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
This study evaluated the clinical outcomes of balloon-occluded retrograde transvenous obliteration (BRTO) for the treatment of hemorrhage from gastric varices (GV) in Korean patients with liver ...cirrhosis (LC).
We retrospectively analyzed data from 183 LC patients who underwent BRTO for GV bleeding in 6 university-based hospitals between January 2001 and December 2010.
Of the 183 enrolled patients, 49 patients had Child-Pugh (CP) class A LC, 105 had CP class B, and 30 had CP class C at the time of BRTO. BRTO was successfully performed in 177 patients (96.7%). Procedure-related complications (e.g., pulmonary thromboembolism and renal infarction) occurred in eight patients (4.4%). Among 151 patients who underwent follow-up examinations of GV, 79 patients (52.3%) achieved eradication of GV, and 110 patients (72.8%) exhibited marked shrinkage of the treated GV to grade 0 or I. Meanwhile, new-appearance or aggravation of esophageal varices (EV) occurred in 54 out of 136 patients who underwent follow-up endoscopy (41.2%). During the 36.0±29.2 months (mean±SD) of follow-up, 39 patients rebled (hemorrhage from GV in 7, EV in 18, nonvariceal origin in 4, and unknown in 10 patients). The estimated 3-year rebleeding-free rate was 74.8%, and multivariate analysis showed that CP class C was associated with rebleeding (odds ratio, 2.404; 95% confidence-interval, 1.013-5.704; P=0.047).
BRTO can be performed safely and effectively for the treatment of GV bleeding. However, aggravation of EV or bleeding from EV is not uncommon after BRTO; thus, periodic endoscopy to follow-up of EV with or without prophylactic treatment might be necessary in LC patients undergoing BRTO.
Mode conversion of high-power electromagnetic microwave (HPEM) was successfully accomplished using a coaxial-beam rotating antenna (COBRA) in an X-band relativistic backward-wave oscillator (RBWO). ...The mode conversion from the TM 01 mode to the circularly polarized TE 11 -likeness mode was identified by both cold test and hot test. To observe whether mode conversion is effective or not, the radiation pattern of TE 11 -likeness mode by COBRA lens was compared with the case of the radiation pattern of TM 01 mode using simple horn antenna. Their radiation patterns could be described by fluorescent lamps. The experimental results of radiation pattern measurements are shown to be in a reasonable agreement with the simulated one. The maximum value of RF output power appeared at the center of COBRA lens from the experimental results.
The molecular mechanisms of preconditioning-induced ischemic tolerance (PCIT) have yet to be elucidated. We investigated whether minimal expression levels of COX-2 induced by preconditioning trigger ...HO-1, thereby inducing the synthesis of cytoprotective proteins. We show that both COX-2 and HO-1 are induced in rat brains subjected to preconditioning by middle cerebral artery (MCA) occlusion for 10min followed by different amounts of reperfusion time (1–24h). Although preconditioning significantly reduced the brain infarct size against severe ischemia (24h MCA occlusion), pretreatment with the COX-2-selective inhibitor rofecoxib increased infarct size and abolished PCIT-induced COX-2 and HO-1 expression in vivo. We also found that PGE2 increased the phosphorylation of Akt, which was significantly inhibited by the PI3 kinase inhibitor LY294002. Taken together, we conclude that the kinetic changes in COX-2 induction during the reperfusion period following preconditioning may be important for ischemic tolerance.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Transglutaminase2 (TGase2) activates Rho-associated kinase (ROCK), an important mediator of ischemia–reperfusion (IR) injury, through polyamination of RhoA. Cystamine, an oxidized dimer of cysteamine ...inhibits the transamidation activity of TGase2. We examined whether addition of cystamine to an organ preservation solution protects rat cardiomyocyte cells (H9C2) from cell death in IR injury. H9C2 cells were stored under hypoxic conditions at 4
°C in laboratory-made preservation solution (SNU) or SNU solution supplemented with cystamine (SNU-C1), and cell preservation in the two solutions was compared by measuring the release of lactate dehydrogenase. The cells were preserved more effectively in SNU-C1 than in SNU solution. Cystamine inhibited the intracellular activity of TGase2 which increased during cold storage or reoxygenation. The inhibition of TGase2 by cystamine reduced the polyamination of RhoA, the interaction between RhoA and ROCK2, and F-actin formation. Cystamine also prevented the activation of caspases during cold storage. These results suggest that addition of cystamine to the organ preservation solution significantly enhances cardiomyocytes preservation apparently by inhibiting TGase2-mediated RhoA-ROCK pathway and that TGase2 may play an important role in IR injury by regulating ROCK.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
The thermoelectric properties of In4Se3 compounds were investigated, and their unique charge and thermal transport behaviours were interpreted in terms of condenson state for the first time. The ...effects of Sn-doping both on the carrier localization and lattice thermal conductivity were consistent with the proposed condenson model. Some important physical properties, such as the band gap energy of In4Se3 and the binding energy of the condenson state, are also presented.
Two new phenolic compounds, 4- O -glucopyranosyl-5- O -caffeoylshikimic acid (1) and 2,3-digalloyl oregonin (2), were isolated along with eight known phenolic compounds (3 – 10) from an 80% acetone ...extract of Alnus sibirica leaves. The chemical structures of these compounds were elucidated using 1D/2D nuclear magnetic resonance and high resolution-MS. The anti-oxidative activities of these compounds were determined by assaying their 1,1-diphenyl-2-picrylhydrazyl radical and nitroblue tetrazolium superoxide anion scavenging activity. All of the isolated phenolic compounds (1 – 10) exhibited potent anti-oxidative activities. In particular, 2 and 4, which are diarylheptanoids, and 10 which is ellagitannin exhibited excellent anti-oxidative activities with almost the same potency as that of the positive controls L -ascorbic acid and allopurinol.
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BFBNIB, GIS, IJS, KISLJ, NUK, PNG, UL, UM, UPUK
Introduction: Extracellular nucleotides are released and detectable in a high concentration within the tumor microenvironment. G protein-coupled P2Y sub(2) nucleotide receptor (P2Y sub(2)R) is ...activated equipotently by adenosine triphosphate (ATP) and uridine 5'-triphosphate (UTP), which mediate proinflammatory responses such as cell migration and proliferation. However, the role of P2Y sub(2)R in the process of cancer metastasis remains unclear. This study aimed to determine the role of P2Y sub(2)R in the proliferation, migration and invasion of highly metastatic MDA-MB-231 breast cancer cells through crosstalk with endothelial cells (ECs). Methods: ATP release and P2Y sub(2)R activity between high metastatic breast cancer cell MDA-MB-231 and low metastatic breast cancer cell MCF-7 were compared. Then, the role of P2Y sub(2)R on tumor growth and invasion via crosstalk with ECs was examined in vitro, using MDA-MB-231 cells and ECs transfected with control- or P2Y sub(2)R-siRNA, and in vivo, using an animal model injected with control-shRNA- or P2Y sub(2)R-shRNA-transfected MDA-MB-231 cells. Results: We found that this highly metastatic breast cancer cell line released higher levels of ATP and showed a higher P2Y sub(2)R activity in comparison to a low metastatic breast cancer cell line, MCF-7. In MDA-MB-231 cells, P2Y sub(2)R activation by ATP or UTP increased proliferation at 24 or 72 hours, which was abolished by P2Y sub(2)R knock-down. In addition, the adhesion of MDA-MB-231 cells to ECs and cell migration were both significantly increased by ATP or UTP through the expression of intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) in MDA-MB-231 or ECs but not in cells where P2Y sub(2)R was knocked down. Furthermore, ATP- or UTP-mediated activation of P2Y sub(2)R induced MDA-MB-231 invasion through ECs, increased matrix metalloproteinase-9 (MMP-9) activity and vascular endothelial growth factor (VEGF) production in MDA-MB-231 and induced the phosphorylation of vascular endothelial (VE)-cadherin in ECs. Tumor growth and metastasis to other tissues were dramatically reduced, and body weight was increased in mice injected with P2Y sub(2)R-shRNA-transfected MDA-MB-231 cells compared to mice injected with control shRNA-transfected MDA-MB-231 cells. Conclusion: This study suggests that P2Y sub(2)R may play an important role in cancer metastasis via modulation of the crosstalk between cancer cells and ECs.
Sn-precursor nanowires (NWs) were prepared by refluxing a solution containing tin oxalate (SnC
2O
4) and ethylene glycol. The precursor NWs were heat-treated at 600
°C, which successfully transformed ...them into SnO
2 NWs without undergoing any morphological change. The morphology of the SnO
2 NWs could be manipulated either by controlling the SnC
2O
4 concentration or by adding easily reducible noble metal salts, such as PdCl
3, AgNO
3 or RuCl
3·H
2O. The thicker and shorter SnO
2 NWs, which resulted from the use of a high SnC
2O
4 concentration during the preparation, showed lower gas sensitivity due to their decreased gas sensing surface area. The addition of catalytically active Pd, Ag, or Ru not only changed the gas sensitivity but also significantly shortened the gas recovery times. The gas sensing characteristics of the SnO
2 NWs were related to the NW morphology and, when applicable, the catalyst used.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
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