THE KINEMATIC ANALYSIS OF 500M SPRINT START IN 2005 WORLD SHORT TRACK SPEED SKATING CHAMPIONSHIP

A field study was performed attempting a kinematic estimation for six female foreign skaters, who participated in the 500m female final round competition. The three dimensional motion analysis with DLT method was executed using four video cameras for analyzing the actual competition situation. The following conclusions are drawn; the elapsed time by phase in start motion of the foreign skaters appeared shorter than those of Korean skaters, so the start training of Korean skaters should be strengthened. Also the displacement of COG in the foreign skaters appeared shorter than those of Korean skaters. The velocity of COG and maximum velocity of skate blade of foreign skaters are faster than those of Korean skaters. And the foreign skaters showed the superior early velocity change

A micromachined flow shear-stress sensor based on thermal transfer principles

Microhot-film shear-stress sensors have been developed by using surface micromachining techniques. The sensor consists of a suspended silicon-nitride diaphragm located on top of a vacuum-sealed cavity. A heating and heat-sensing element, made of polycrystalline silicon material, resides on top of the diaphragm. The underlying vacuum cavity greatly reduces conductive heat loss to the substrate and therefore increases the sensitivity of the sensor. Testing of the sensor has been conducted in a wind tunnel under three operation modes-constant current, constant voltage, and constant temperature. Under the constant-temperature mode, a typical shear-stress sensor exhibits a time constant of 72 μs

Micro thermal shear stress sensor with and without cavity underneath

Micro hot-film shear-stress sensors have been designed and fabricated by surface micromachining technology compatible with IC technology. A poly-silicon strip, 2 µm x 80 µm, is deposited on the top of a thin silicon nitride film and functions as the sensor element. By using sacrificial-layer technique, a cavity (vacuum chamber), 200 x 200 x 2 µm^3, is placed between the silicon nitride film and silicon substrate. This cavity significantly decreases the heat loss to the substrate. For comparison purposes, a sensor structure without a cavity has also been designed and fabricated on the same chip. Theoretical analyses for the two vertical structures with and without a cavity show that the former has a lower frequency response and higher sensitivity than the latter. When the sensor is operated in constant temperature mode, the cut-off frequencies can reach 130 k-Hz and 9 k-Hz respectively for the sensors without and with cavities

Impact factor of Korean Journal of Pediatrics on Korean Medical Citation Index and Science Citation Index of Web of Science

PurposeThe total number of times a paper is cited, also known as the impact factor (IF) of a medical journal, is widely implied in evaluating the quality of a research paper. We evaluated the citation index data as an IF of Korean J Pediatr in Korean Medical Citation Index (KoMCI) and JCI of Web of Science.MethodsWe calculated the IF of Korean J Pediatr at KoMCI supervised by Korean Association of Medical Journal Editors. And we estimated the IF of Korean J Pediatr by the JCI of Web of Science although it was never officially reported.ResultsThe IF of Korean J Pediatr on KoMCI has increased from 0.100 in the year 2000, to 0.205 in 2008, and 0.326 in 2009. Although the IF of Korean J Pediatr was 0.006 in 2005, 0.018 in 2006, 0.028 in 2008, 0.066 in 2009, and 0.018 in 2010 according to the JCI of Web of Science, the number of citations are steadily increasing.ConclusionUnderstanding and realizing the current status will be a stepping stone for further improvement. The next objective of the Korean J Pediatr is to become registered in the SCI or SCIE. Increasing the IF according to the JCI of Web of Science is crucial in order to achieve this goal

Fluidic shear-stress measurement using surface-micromachined sensors

A poly-silicon hot-film shear-stress sensor insulated by a vacuum-chamber underneath has been designed and fabricated by the surface micromachining technology. The sensor is operated at both constant current and constant temperature modes. The dynamic performance (including time constant and cut-off frequency) measurement, calibration, and temperature compensation of the sensor have been realized

A surface-micromachined shear stress imager

A new MEMS shear stress sensor imager has been developed and its capability of imaging surface shear stress distribution has been demonstrated. The imager consists of multi-rows of vacuum-insulated shear stress sensors with a 300 /spl mu/m pitch. This small spacing allows it to detect surface flow patterns that could not be directly measured before. The high frequency response (30 kHz) of the sensor under constant temperature bias mode also allows it to be used in high Reynolds number turbulent flow studies. The measurement results in a fully developed turbulent flow agree well with the numerical and experimental results previously published

C-reactive Protein Overexpression in the Background Liver of Hepatitis B Virus–Associated Hepatocellular Carcinoma Is a Prognostic Biomarker

Background Chronic hepatitis B virus (HBV) infection is a leading cause of hepatocellular carcinoma (HCC). Peripheral blood C-reactive protein (CRP) concentration and CRP overexpression in HCC cells are proven to be prognostic markers for HCC, but the significance of CRP expression in non-neoplastic hepatocytes, which are the primary origin of CRP, has not been studied. This study was conducted to determine the clinicopathologic significance of CRP immunoreactivity in the background liver of HBV-associated HCC. Methods CRP immunostaining was done on tissue microarrays of non-neoplastic liver tissues obtained from surgically resected, treatment-naïve HBV-associated HCCs (n = 156). The relationship between CRP immunoreactivity and other clinicopathologic parameters including cancer-specific survival was analyzed. CRP immunoreactivity was determined using a 4-tier grading system: grades 0, 1, 2, and 3. Results CRP was positive in 139 of 156 cases (89.1%) of non-neoplastic liver in patients with HCCs: grade 1 in 83 cases (53.2%); grade 2 in 50 cases (32.1%); and grade 3 in six cases (3.8%). The patients with diffuse CRP immunoreactivity (grade 3) had decreased cancer-specific survival (p = .031) and a tendency for shorter interval before early recurrence (p = .050). The degree of CRP immunoreactivity correlated with serum CRP concentration (p < .001). Conclusions CRP immunoreactivity in non-neoplastic liver is a novel biomarker for poor cancer-specific survival of HBV-associated HCC and correlates with serum CRP concentration

Micro thermal shear stress sensor with and without cavity underneath

Micro hot-film shear-stress sensors have been designed and fabricated by surface micromachining technology compatible with IC technology. A poly-silicon strip, 2 µm x 80 µm, is deposited on the top of a thin silicon nitride film and functions as the sensor element. By using sacrificial-layer technique, a cavity (vacuum chamber), 200 x 200 x 2 µm^3, is placed between the silicon nitride film and silicon substrate. This cavity significantly decreases the heat loss to the substrate. For comparison purposes, a sensor structure without a cavity has also been designed and fabricated on the same chip. Theoretical analyses for the two vertical structures with and without a cavity show that the former has a lower frequency response and higher sensitivity than the latter. When the sensor is operated in constant temperature mode, the cut-off frequencies can reach 130 k-Hz and 9 k-Hz respectively for the sensors without and with cavities