1,325 research outputs found

    Improving the Performance of the Space Surveillance Telescope as a Function of Seeing Parameter

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    This research paper investigates ways to improve the detection capability and predict the performance of the Space Surveillance Telescope (SST) system when it\u27s relocated to Exmouth, Australia. The dataset collected by the SST observing the Geosynchronous Earth Orbit (GEO) satellite, ANIK-F1, entering the earth\u27s eclipse is used to test the performance of the three existing and one new detection algorithm. The three existing algorithms are the point detection (Binary Hypothesis Test (BHT)), correlation detection (CD-BHT), and Multi-hypothesis Test using ten hypotheses (MHT10), and the new detection algorithm is the Multi-hypothesis Test using six hypotheses (MHT6). To improve the accuracy and validness of the comparison, a new method of obtaining the true atmospheric seeing parameter, terminator (point before the object entering the eclipse), and parameters used for the comparison are also investigated. It is found that the MHTs vastly outperform the BHTs, and the MHT6 offers a similar or improved performance over the MHT10, but requiring only half of the computing power

    How dsDNA breathing enhances its flexibility and instability on short length scales

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    We study the unexpected high flexibility of short dsDNA which recently has been reported by a number of experiments. Via the Langevin dynamics simulation of our Breathing DNA model, first we observe the formation of bubbles within the duplex and also forks at the ends, with the size distributions independent of the contour length. We find that these local denaturations at a physiological temperature, despite their rare and transient presence, can lower the persistence length drastically for a short DNA segment in agreement with experiment

    Recovery of Heavy Minerals from Korean Beach Sand

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    In order to establish the optimized recovery process for heavy minerals from beach sand, we investigated the physical separation methods such as gravity and magnetic separation followed by mineralogical characterization. There was clear relationship between the particle size and the heavy mineral content that the heavy minerals were mostly concentrated in the particles below 100mesh. Grav-ity separation using the spiral and shaking table sepa-rators made it possible to concentrate heavy minerals by rejecting the light and coarse particles consist mainly of quartz. The high-intensity magnetic separator and subsequent induced magnetic separator were applied to fractionate magnetic particles into three fractions accor-ding to their magnetic susceptibility. The content of TiO, of high magnetic susceptible ilmenite-rich fraction was 43.98wt.% while those of ZrO2 of non-magnetic and magnetic residue were 6.78wt.% and 3.11 wt. %. respectively

    Photocatalytic Ohmic layered nanocomposite for efficient utilization of visible light photons

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    The WO3/W/PbBi2Nb1.9Ti0.1O9 photocatalyst was fabricated by depositing the tungsten clusters over the p-type perovskite base material with the chemical vapor deposition method, and later partly oxidizing the surfaces of these clusters to obtain n-type WO3 overlayers and W metal layer as an Ohmic junction. This NCPC showed unprecedented high activity for the photocatalytic oxidation of water, photocurrent generation, and acetaldehyde decomposition under visible light irradiation (lambda >= 420 nm). (c) 2006 American Institute of Physicsclose313

    Failure of a Randomized, Double-Blind, Placebo-Controlled Study to Evaluate the Efficacy of H. pylori Eradication in H. pylori-Infected Patients with Functional Dyspepsia

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    BACKGROUND/AIMS: The role of Helicobacter pylori eradication in patients with functional dyspepsia (FD) is still uncertain. We originally planned a randomized clinical study to observe dyspeptic symptoms after H. pylori eradication therapy. However, we failed to complete the study; therefore, we analyzed the factors that affected the failure of the study. METHODS: Interviews and questionnaire surveys were conducted to analyze the factors that induced early termination from the study. RESULTS: Many patients were screened by gastroenterologists at 11 tertiary referral hospitals between July 2009 and August 2010; however, only 4 patients met the enrollment criteria. Most patients who visited our clinics had been experiencing FD symptoms for less than 6 months or were already taking medication. They also demanded to continue taking medications and using other drugs. Only 3 of the 4 patients signed informed consent. CONCLUSIONS: The application of the current Rome III criteria to FD is difficult to evaluate in Korean patients with dyspeptic symptoms because of the early medical evaluation. Most Korean patients who were diagnosed with FD by the Rome III criteria did not overcome their fear of being unable to use rescue medications during the study period.ope

    The PEX7-Mediated Peroxisomal Import System Is Required for Fungal Development and Pathogenicity in Magnaporthe oryzae

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    In eukaryotes, microbodies called peroxisomes play important roles in cellular activities during the life cycle. Previous studies indicate that peroxisomal functions are important for plant infection in many phytopathogenic fungi, but detailed relationships between fungal pathogenicity and peroxisomal function still remain unclear. Here we report the importance of peroxisomal protein import through PTS2 (Peroxisomal Targeting Signal 2) in fungal development and pathogenicity of Magnaporthe oryzae. Using an Agrobacterium tumefaciens-mediated transformation library, a pathogenicity-defective mutant was isolated from M. oryzae and identified as a T-DNA insert in the PTS2 receptor gene, MoPEX7. Gene disruption of MoPEX7 abolished peroxisomal localization of a thiolase (MoTHL1) containing PTS2, supporting its role in the peroxisomal protein import machinery. ΔMopex7 showed significantly reduced mycelial growth on media containing short-chain fatty acids as a sole carbon source. ΔMopex7 produced fewer conidiophores and conidia, but conidial germination was normal. Conidia of ΔMopex7 were able to develop appressoria, but failed to cause disease in plant cells, except after wound inoculation. Appressoria formed by ΔMopex7 showed a defect in turgor generation due to a delay in lipid degradation and increased cell wall porosity during maturation. Taken together, our results suggest that the MoPEX7-mediated peroxisomal matrix protein import system is required for fungal development and pathogenicity M. oryzae

    Profiles of Multidrug Resistance Protein-1 in the Peripheral Blood Mononuclear Cells of Patients with Refractory Epilepsy

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    BACKGROUND: About one third of patients with epilepsy become refractory to therapy despite receiving adequate medical treatment, possibly from multidrug resistance. P-glycoprotein, encoded by multidrug resistance protein-1 (MDR1) gene, at the blood brain barrier is considered as a major factor mediating drug efflux and contributing to resistance. Given that peripheral blood mononuclear cells (PBMNCs) express MDR1, we investigated a MDR1 status of PBMNCs in various subsets of epilepsy patients and demonstrated their association with clinical characteristics. METHODOLOGY/PRINCIPAL FINDINGS: Clinical and MDR1 data were collected from 140 patients with epilepsy, 30 healthy volunteers, and 20 control patients taking anti-epileptic drugs. PBMNCs were isolated, and basal MDR1 levels and MDR1 conformational change levels were measured by flow cytometry. MDR1 profiles were analyzed according to various clinical parameters, including seizure frequency and number of medications used in epilepsy patients. Epilepsy patients had a higher basal MDR1 level than non-epilepsy groups (p<0.01). Among epilepsy patients, there is a tendency for higher seizure frequency group to have higher basal MDR1 level (p = 0.059). The MDR1 conformational change level was significantly higher in the high-medication-use group than the low-use group (p = 0.028). Basal MDR1 (OR = 1.16 [95% CI: 1.060-1.268]) and conformational change level (OR = 1.11 [95% CI: 1.02-1.20]) were independent predictors for seizure frequency and number of medications, respectively. CONCLUSIONS/SIGNIFICANCE: The MDR1 profile of PBMNCs is associated with seizure frequency and medication conditions in patients with epilepsy

    Cinnamon extract induces tumor cell death through inhibition of NFκB and AP1

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    <p>Abstract</p> <p>Background</p> <p><it>Cinnamomum cassia </it>bark is the outer skin of an evergreen tall tree belonging to the family Lauraceae containing several active components such as essential oils (cinnamic aldehyde and cinnamyl aldehyde), tannin, mucus and carbohydrate. They have various biological functions including anti-oxidant, anti-microbial, anti-inflammation, anti-diabetic and anti-tumor activity. Previously, we have reported that anti-cancer effect of cinnamon extracts is associated with modulation of angiogenesis and effector function of CD8<sup>+ </sup>T cells. In this study, we further identified that anti-tumor effect of cinnamon extracts is also link with enhanced pro-apoptotic activity by inhibiting the activities NFκB and AP1 in mouse melanoma model.</p> <p>Methods</p> <p>Water soluble cinnamon extract was obtained and quality of cinnamon extract was evaluated by HPLC (High Performance Liquid Chromatography) analysis. In this study, we tested anti-tumor activity and elucidated action mechanism of cinnamon extract using various types of tumor cell lines including lymphoma, melanoma, cervix cancer and colorectal cancer <it>in vitro </it>and <it>in vivo </it>mouse melanoma model.</p> <p>Results</p> <p>Cinnamon extract strongly inhibited tumor cell proliferation <it>in vitro </it>and induced active cell death of tumor cells by up-regulating pro-apoptotic molecules while inhibiting NFκB and AP1 activity and their target genes such as <it>Bcl-2</it>, <it>BcL-xL </it>and <it>survivin</it>. Oral administration of cinnamon extract in melanoma transplantation model significantly inhibited tumor growth with the same mechanism of action observed <it>in vitro</it>.</p> <p>Conclusion</p> <p>Our study suggests that anti-tumor effect of cinnamon extracts is directly linked with enhanced pro-apoptotic activity and inhibition of NFκB and AP1 activities and their target genes <it>in vitro </it>and <it>in vivo </it>mouse melanoma model. Hence, further elucidation of active components of cinnamon extract could lead to development of potent anti-tumor agent or complementary and alternative medicine for the treatment of diverse cancers.</p
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