This paper presents a numerical investigation of the characteristics of the two-dimensional laminar flow around two rotating circular cylinders in side-by-side arrangements. In order to consider the ...combined effects of the rotation and the spacing between two cylinders on the flow, numerical simulations are performed at a various range of absolute rotational speeds
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for four different gap spacings of 3, 1.5, 0.7 and 0.2 at Reynolds number of 100 showing the typical two-dimensional vortex shedding. As
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increases, the flow changes its condition from periodic to steady after a critical rotational speed, which depends on the gap spacing. In the cases of gap spacings of 3 and 0.2, the wake keeps the same pattern, until flow reaches the steady state. However, for the gap spacings of 1.5 and 0.7, the wake patterns change in the unsteady regimes. For the cases in which the flow is unsteady, the Strouhal number strongly depends on the gap. For a fixed gap spacing, the variation of the Strouhal number is significant when the wake pattern is changed according to the rotational speed. Regardless of the gap spacing, as
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increases, the lift increases and the drag decreases. Quantitative information about the flow variables such as the pressure coefficient and wall vorticity distributions on the cylinders is highlighted.
During photosynthesis, triose-phosphates (trioseP) exported from the chloroplast to the cytosol are converted to sucrose via cytosolic fructose-1,6-bisphosphatase (cFBPase). Expression analysis in ...rice suggests that OscFBP1 plays a major role in the cytosolic conversion of trioseP to sucrose in leaves during the day. The isolated OscFBP1 mutants exhibited markedly decreased photosynthetic rates and severe growth retardation with reduced chlorophyll content, which results in plant death. Analysis of primary carbon metabolites revealed both significantly reduced levels of sucrose, glucose, fructose and starch in leaves of these mutants, and a high accumulation of sucrose to starch in leaves of rice plants. In the oscfbp1 mutants, products of glycolysis and the TCA cycle were significantly increased. A partitioning experiment of ¹⁴C-labelled photoassimilates revealed altered carbon distributions including a slight increase in the insoluble fraction representing transitory starch, a significant decrease in the neutral fraction corresponding to soluble sugars and a high accumulation of phosphorylated intermediates and carboxylic acid fractions in the oscfbp1 mutants. These results indicate that the impaired synthesis of sucrose in rice cannot be sufficiently compensated for by the transitory starch-mediated pathways that have been found to facilitate plant growth in the equivalent Arabidopsis mutants.
During limb lengthening over an intramedullary nail, decisions regarding external fixator removal and weightbearing depend on the amount of callus seen at the lengthening area on radiographs. ...However, this method is subjective and objective evaluation of the amount of callus likely would minimize nail or interlocking screw breakage and refracture after fixator removal. We asked how many cortices with full corticalization of the newly formed bone at the lengthening area are needed to allow fixator removal and full weightbearing and how to radiographically determine the stage of corticalization. We retrospectively reviewed 17 patients (34 lengthenings) who underwent bilateral tibial lengthenings over an intramedullary nail. The average gain in length was 7.2 ± 3.4 cm. We determined the pixel value ratio (ratio of pixel value of regenerate versus the mean pixel value of adjacent bone) of the lengthened area on radiographs. There were no nail or screw breakage and refracture. Partial weightbearing with crutches was permitted when the pixel value ratio was 1 in two cortices and full weightbearing without crutches was permitted when the pixel value ratio was 1 in three cortices. The pixel value ratio on radiographs can be an objective parameter for callus measurement and may provide guidelines for the timing of external fixator removal. We cannot determine from our limited data the minimum pixel value in how many cortices would suggest safe removal, but we can say our criteria were not associated with subsequent refracture.
Gastroesophageal reflux is a commonly encountered condition, but detailed data on reflux symptoms in Asian countries are lacking.
To evaluate the prevalence and to document the clinical spectrum of ...endoscopic reflux esophagitis (RE).
A total 25,536 subjects underwent an upper gastrointestinal endoscopic examination as part of a health check, and completed a gastroesophageal reflux questionnaire. Endoscopic findings classified according to the Los Angeles (LA) classification and the data from gastroesophageal reflux questionnaire were analyzed.
On the basis of endoscopic findings, 2019 subjects (7.91%) were found to have RE: 5.87% in LA-A; 1.84% in LA-B; 0.18% in LA-C; and 0.02% in LA-D. Heartburn, acid regurgitation, chest pain, hoarseness, globus sensation, cough, and epigastric soreness were found to be associated with RE (P<0.05). Heartburn, acid regurgitation, and epigastric soreness were more frequent in LA-B than in LA-A (P<0.05). Epigastric soreness was most bothersome in LA-A and LA-B, and acid regurgitation was most bothersome in LA-C and LA-D (P<0.01). Heartburn, hoarseness, and globus sensation were more frequent in men with RE, and acid regurgitation was most common in women.
The prevalence of RE was found to be 7.91% in Korea, and the profiles of reflux symptoms were found to depend on grade of RE and sex.
Although the acceleration of bone regeneration by radiation has been reported, the mechanisms of action of radiation on bone are unclear. The present results indicate that ionizing ...radiation-stimulated differentiation could result from the generation of reactive oxygen species during radiation exposure. The free radical release is considered as the most important mechanism of bone effect by radiation treatment. In addition, we report that radiation induced transient activation of c-Jun N-terminal kinase/ stress-activated protein kinase (JNK/SAPK) activation and the transcription factor, AP-1. The JNK and AP-1 activation is mediated with radiation-released free radicals in ROS 17/2.8 osteoblasts. These results indicate that ionizing radiation at a single dose of up to 5 Gray stimulates differentiation of ROS 17/2.8 osteoblasts via free radial release which may affect JNK/SAPK and AP-1 activities.
Sulfur-rich copolymers based on poly(sulfur-random-1,3-diisopropenylbenzene) (poly(S-r-DIB)) were synthesized via inverse vulcanization to create cathode materials for lithium–sulfur battery ...applications. These materials exhibit enhanced capacity retention (1005 mAh/g at 100 cycles) and battery lifetimes over 500 cycles at a C/10 rate. These poly(S-r-DIB) copolymers represent a new class of polymeric electrode materials that exhibit one of the highest charge capacities reported, particularly after extended charge–discharge cycling in Li–S batteries.
The synthesis and precise structural characterization of highly ordered three-dimensional close-packed cage-type mesoporous silica is reported. The siliceous mesoporous material is proven to be ...commensurate with the face-centered-cubic Fm3m symmetry in high purity by a combination of experimental and simulated powder X-ray diffraction (XRD) and transmission electron microscopy (TEM) analyses. The cage-type calcined samples were additionally characterized by nitrogen physisorption. The aqueous synthesis method to prepare large cage mesoporous silica with cubic Fm3m structure is based on the use of EO106PO70EO106 triblock copolymer (F127) at low HCl concentrations, with no additional salts or organic additives. Here, emphasis is put on the low HCl concentration regime, allowing the facile thermodynamic control of the silica−triblock copolymer mesophase self-assembly. Further, simple application of hydrothermal treatments at various temperatures ranging from 45 to 150 °C enables the tailoring of the mesopore diameters and apertures. The combination of experimental and simulated XRD patterns and TEM images is confirmed to be a very powerful means for the accurate elucidation of the structure of new mesoporous materials.
To investigate whether p38 small-interfering RNA-loaded nanoparticles (p38 siRNA NPs) attenuate spinal nerve ligation (SNL)-induced neuropathic pain in rats by suppressing spinal microglia activation ...via p38 targeting.
After synthesizing p38 siRNA NPs with sonication, physical characteristics were measured for size and zeta potential. p38 siRNA NPs were then administrated intrathecally into SNL rats if they could reduce pain behavior excellently.
p38 siRNA NPs significantly reduced mechanical allodynia as well as microgliosis in the spinal dorsal horns of SNL rats, consistent with a downregulation of p38-related proinflammatory mediators.
As p38 in the spinal microglia plays a critical role in neuropathic pain, we expect that p38 siRNA NPs could be a promising tool for the treatment of neuropathic pain.
Chromosome microdissection and the reverse FISH technique is one of the most useful methods for the identification of structurally abnormal chromosomes. In particular, the laser microbeam ...microdissection (LMM) method allows rapid isolation of a target chromosome or a specific region of chromosomes without damage of genetic materials and contamination. Isolated chromosomes were directly amplified by the degenerate oligonucleotide-primed polymerase chain reaction (DOP-PCR), and then the FISH probes labeled with spectrum green- or spectrum red-dUTP were generated by nick-translation.
다자유도 곡선맞춤법을 이용한 감쇠보 모델의 실험 진동해석 민천홍(CHEON-HONG MIN); 박한일(HAN-IL PARK); 배수룡(SOO-RYONG BAE)
Han-guk haeyang gonghak hoeji (Online),
2008, Letnik:
22, Številka:
1
Journal Article
Recenzirano
Odprti dostop
It is important to reduce the vibration and noise of submarines and ships. For the purpose of noise reduction, various researches are actively being conducted on the employment of complex structures. ...However, in the case of numerical analysis for complex structures with damping materials, substantial errors can be generated by the absence of an exact damping model. Thus experimental model analysis is necessary for the verification of a numerical analysis for complex structures. In this research, vibration experiments are conducted in order to ascertain the vibration properties of cantilever beam attached damping materials. First, an initial value is obtained by using a direct linear method. Next, based on this initial value, the exact modal parameters of the cantilever beam are obtained by using the Newton-Raphson method.
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