2,347 research outputs found

    A High Precision Test Method And The Related Equipment For Smart Water Meters

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    We are now developing a smart water meter dedicated to smart water grid systems. The primary goal of our reseach is to make the smart water meters with higher precision compared with typical water meters. For instance, the range of the allowable measurement errors for the flow rate in the lower zone of the second level precision water meter is set to +-5% by the Korea Standard. However, with ours the range is decreased to +- 3% for the same condition. Therefore it is necessary to build a high precision test method and the related equipment for evaluating the performance of our developing water meters. Both the international standards, ISO-4063-3 and OIML-R049-2 specifications, define the performance tests that are intended to verify that water meters with electronic devices perform and functions as intended in a specified environment and under specified conditions.However, most of the test equipments in Korea does not satisfy completely both of the international standards. In addition, they opt to adopt volumetric measurement method instead of mass measurement method which typically induces a better result for the uncertainty in measurement. In this paper, we present a test method with the mass measurement system. Reference water flow will be measured as a mass by using the load cell. Each smart water meter sends the massured flow reguarly to the centralized system through Zigbee communication protocol. We expect that our proposed test method and equipment fully satisfies the Korea standard as well as both of the international standards

    The Effects of Loranthus parasiticus

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    This study is undertaken to evaluate cognitive enhancing effect and neuroprotective effect of Loranthus parasiticus. Cognitive enhancing effect of Loranthus parasiticus was investigated on scopolamine-induced amnesia model in Morris water maze test and passive avoidance test. We also examined the neuroprotective effect on glutamate-induced cell death in HT22 cells by MTT assay. These results of Morris water maze test and passive avoidance test indicated that 10 and 50 mg/kg of Loranthus parasiticus reversed scopolamine-induced memory deficits. Loranthus parasiticus also protected against glutamate-induced cytotoxicity in HT22 cells. As a result of in vitro test for elucidating possible mechanism, Loranthus parasiticus inhibited AChE activity, ROS production, and Ca2+ accumulation. Loranthus parasiticus showed memory enhancing effect and neuroprotective effect and these effects may be related to inhibition of AChE activity, ROS level, and Ca2+ influx

    Nanostructured Iron Sulfide/N, S Dual-Doped Carbon Nanotube-Graphene Composites as Efficient Electrocatalysts for Oxygen Reduction Reaction

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    Nanostructured FeS dispersed onto N, S dual-doped carbon nanotube-graphene composite support (FeS/N,S:CNT-GR) was prepared by a simple synthetic method. Annealing an ethanol slurry of Fe precursor, thiourea, carbon nanotube, and graphene oxide at 973 K under N-2 atmosphere and subsequent acid treatment produced FeS nanoparticles distributed onto the N, S-doped carbon nanotube-graphene support. The synthesized FeS/N,S:CNT-GR catalyst exhibited significantly enhanced electrochemical performance in the oxygen reduction reaction (ORR) compared with bare FeS, FeS/N,S:GR, and FeS/N,S:CNT with a small half-wave potential (0.827 V) in an alkaline electrolyte. The improved ORR performance, comparable to that of commercial Pt/C, could be attributed to synergy between the small FeS nanoparticles with a high activity and the N, S-doped carbon nanotube-graphene composite support providing high electrical conductivity, large surface area, and additional active sites

    Skin care benefits of bioactive compounds isolated from Zanthoxylum piperitum DC. (Rutaceae)

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    Purpose: To investigate skin care efficacies of Zanthoxylum pipetitum extract and isolated compounds. Methods: Ethanol extracts of leaves, branches and fruits of what were partitioned into n-hexane, chloroform, ethyl acetate, n-butanol and aqueous layers and some fractions were further analyzed to isolate five compounds. The isolated compounds were identified based on the proton and carbon nuclear magnetic resonance (NMR) spectra. Cosmetic efficacy tests of the extracts and isolated compounds were evaluated by in vitro tests. Results: Phytochemical studies of the chloroform and ethyl acetate layers led to the isolation of five compounds; quercitrin (1), afzelin (2), hydroxy-α-sanshool (3), α-sanshool (4) and hyperoside (5). In activity tests, the extracts showed inhibitory activity against inflammation response and melanin synthesis, and induction of procollagen type I C-peptide (PIP). Among the isolated compounds, hydroxy-α-sanshool (3) and α-sanshool (4) displayed significant anti-inflammatory activity. Conclusion: The results demonstrate that Z. piperitum extract and its active compounds possess a significant potential as a cosmeeutical agent for enhancing skin quality

    Normal stress difference-driven particle focusing in nanoparticle colloidal dispersion

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    Colloidal dispersion has elastic properties due to Brownian relaxation process. However, experimental evidence for the elastic properties, characterized with normal stress differences, is elusive in shearing colloidal dispersion, particularly at low Peclet numbers (Pe < 1). Here, we report that single micrometer-sized polystyrene (PS) beads, suspended in silica nanoparticle dispersion (8 nm radius; 22%, v/v), laterally migrate and form a tightly focused stream by the normal stress differences, generated in pressure-driven microtube flow at low Pe. The nanoparticle dispersion was expected to behave as a Newtonian fluid because of its ultrashort relaxation time (2 mu s), but large shear strain experienced by the PS beads causes the notable non-Newtonian behavior. We demonstrate that the unique rheological properties of the nanoparticle dispersion generate the secondary flow in perpendicular to mainstream in a noncircular conduit, and the elastic properties of blood plasma-constituting protein solutions are elucidated by the colloidal dynamics of protein molecules

    Observation of First-Order Metal-Insulator Transition without Structural Phase Transition in VO_2

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    An abrupt first-order metal-insulator transition (MIT) without structural phase transition is first observed by current-voltage measurements and micro-Raman scattering experiments, when a DC electric field is applied to a Mott insulator VO_2 based two-terminal device. An abrupt current jump is measured at a critical electric field. The Raman-shift frequency and the bandwidth of the most predominant Raman-active A_g mode, excited by the electric field, do not change through the abrupt MIT, while, they, excited by temperature, pronouncedly soften and damp (structural MIT), respectively. This structural MIT is found to occur secondarily.Comment: 4 pages, 4 figure

    Effects of Psychiatric Factors on Patient-Reported Outcomes after Surgical Correction of Lumbar Degenerative Kyphosis

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    Study DesignA prospective study.PurposeTo identify associations between psychiatric factors and patient-reported outcomes after corrective surgery in patients with lumbar degenerative kyphosis (LDK).Overview of LiteratureThus far, to the best of our knowledge, patient factors that may help predict patient-reported outcomes after corrective surgery for LDK have not been studied.MethodsWe prospectively investigated 46 patients with LDK who underwent surgical correction with a minimum follow-up of 2 years. Demographic data were collected. Short form-36, mental component scores (MCS), physical component scores (PCS), Scoliosis Research Society-22 (SRS-22) scores, and Roland-Morris Disability Questionnaire (RMDQ) scores were determined before the surgery and after 2 years of follow-up. Psychiatric conditions were preoperatively evaluated using the Zung depression scale (ZDS) and Zung anxiety scale (ZAS). Patients were divided into two groups (with or without psychiatric issues), according to baseline ZDS and ZAS scores.ResultsPatients included 43 women and 3 men. Twelve patients were deemed to have psychiatric problems (P group) and 34 patients had no psychiatric problems (NP group). No significant intergroup differences were found in MCS, PCS, SRS-22, and RMDQ scores preoperatively. However, at the 2-year follow-up, a significant intergroup difference was observed between PCS and RMDQ scores. Multiple regression analysis revealed that only the presence of a preoperative psychiatric problem can predict PCS and RMDQ scores. Other factors, such as, gender, age, body mass index, bone mineral density, osteotomy site, number of fusion segments, and instrumented levels did not affect PCS or RMDQ scores.ConclusionsThe presence of a psychiatric factor may be an important risk factor underlying poor physical and pain scores after corrective surgery in patients with LDK. The findings presented here suggest that psychiatric factors should be evaluated prior to surgery for determining the risk of a poor outcome

    Interferometric detection of prostate specific antigen based on enzyme immunoassay

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    AbstractInterferometric detection of Prostate-specific antigen (PSA) based on enzyme immunoassay are investigated. Refractive index changes of substrate are measured for PSA detection. Michelson scheme of optical interferometer was used so as to be applicable to a disposable fluidic chip. When interferometer is used for the measurements of refractive index changes, the detection is over 8 times more sensitive than that of absorbance changes for the same amount of target protein

    THE EFFECTS OF WEARING ROLLER SHOES ON GROUND REACTION FORCE CHARACTERISTICS DURING WALKING

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    Roller shoes have become increasingly popular among children and it features retractable wheels which allowing the user to walk or roll without changing the footwear. Maintaining balance during forward walking with roller shoes is not an easy task. To prevent falling backward, the user needs to lock the knees and tighten the ankles and thighs while the upper body is slightly leaning forward. Constant walking with roller shoes forces the user to walk in a manner much different from normal gait. Prolonged exposure to un-natural stresses on human body forces our body to evolve by strengthening those incorrect, and temporary functions (Clement et aI., 1981). For children, the chronic stress may lead to serious injuries in the lower extremity later in life. If any potential' of injury exists in a movement it is critical to examine the associated forces that may lead to injury. To the best of our knowledge, the effects of wearing roller shoes on ground reaction forces (GRF) characteristics have rarely been studied, especially in the youth population. Thus, the purpose of this study was to compare GRF characteristics during walking wearing jogging and roller shoes

    Plant growth promotion and Penicillium citrinum

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    <p>Abstract</p> <p>Background</p> <p>Endophytic fungi are known plant symbionts. They produce a variety of beneficial metabolites for plant growth and survival, as well as defend their hosts from attack of certain pathogens. Coastal dunes are nutrient deficient and offer harsh, saline environment for the existing flora and fauna. Endophytic fungi may play an important role in plant survival by enhancing nutrient uptake and producing growth-promoting metabolites such as gibberellins and auxins. We screened roots of <it>Ixeris repenes </it>(L.) A. Gray, a common dune plant, for the isolation of gibberellin secreting endophytic fungi.</p> <p>Results</p> <p>We isolated 15 endophytic fungi from the roots of <it>Ixeris repenes </it>and screened them for growth promoting secondary metabolites. The fungal isolate IR-3-3 gave maximum plant growth when applied to waito-c rice and <it>Atriplex gemelinii </it>seedlings. Analysis of the culture filtrate of IR-3-3 showed the presence of physiologically active gibberellins, GA<sub>1</sub>, GA<sub>3</sub>, GA<sub>4 </sub>and GA<sub>7 </sub>(1.95 ng/ml, 3.83 ng/ml, 6.03 ng/ml and 2.35 ng/ml, respectively) along with other physiologically inactive GA<sub>5</sub>, GA<sub>9</sub>, GA<sub>12</sub>, GA<sub>15</sub>, GA<sub>19</sub>, GA<sub>20 </sub>and, GA<sub>24</sub>. The plant growth promotion and gibberellin producing capacity of IR-3-3 was much higher than the wild type <it>Gibberella fujikuroi</it>, which was taken as control during present study. GA<sub>5</sub>, a precursor of bioactive GA<sub>3 </sub>was reported for the first time in fungi. The fungal isolate IR-3-3 was identified as a new strain of <it>Penicillium citrinum </it>(named as <it>P. citrinum </it>KACC43900) through phylogenetic analysis of 18S rDNA sequence.</p> <p>Conclusion</p> <p>Isolation of new strain of <it>Penicillium citrinum </it>from the sand dune flora is interesting as information on the presence of <it>Pencillium </it>species in coastal sand dunes is limited. The plant growth promoting ability of this fungal strain may help in conservation and revegetation of the rapidly eroding sand dune flora. <it>Penicillium citrinum </it>is already known for producing mycotoxin citrinin and cellulose digesting enzymes like cellulase and endoglucanase, as well as xylulase. Gibberellins producing ability of this fungus and the discovery about the presence of GA<sub>5 </sub>will open new aspects of research and investigations.</p
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