• Title/Summary/Keyword: Center-of-mass

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Low Intensity Resistance Exercise Training with Blood Flow Restriction: Insight into Cardiovascular Function, and Skeletal Muscle Hypertrophy in Humans

  • Park, Song-Young;Kwak, Yi Sub;Harveson, Andrew;Weavil, Joshua C.;Seo, Kook E.
    • The Korean Journal of Physiology and Pharmacology
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    • v.19 no.3
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    • pp.191-196
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    • 2015
  • Attenuated functional exercise capacity in elderly and diseased populations is a common problem, and stems primarily from physical inactivity. Decreased function and exercise capacity can be restored by maintaining muscular strength and mass, which are key factors in an independent and healthy life. Resistance exercise has been used to prevent muscle loss and improve muscular strength and mass. However, the intensities necessary for traditional resistance training to increase muscular strength and mass may be contraindicated for some at risk populations, such as diseased populations and the elderly. Therefore, an alternative exercise modality is required. Recently, blood flow restriction (BFR) with low intensity resistance exercise (LIRE) has been used for such special populations to improve their function and exercise capacity. Although BFR+LIRE has been intensively studied for a decade, a comprehensive review detailing the effects of BFR+LIRE on both skeletal muscle and vascular function is not available. Therefore, the purpose of this review is to discuss previous studies documenting the effects of BFR+LIRE on hormonal and transcriptional factors in muscle hypertrophy and vascular function, including changes in hemodynamics, and endothelial function.

Optimum Fabrication Conditions and Reheating Characteristic of Semi-Solid Al-Zn-Mg-(Sc) Alloy by Inclined Cooling Plate (경사냉각판을 이용한 Al-Zn-Mg-(Sc) 반응고 합금 제조의 최적화 및 재가열 특성)

  • Kim, Tae-Hun;Shim, Sung-Yong;Park, Hyung-Won;Lim, Su-Gun
    • Journal of Korea Foundry Society
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    • v.29 no.5
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    • pp.213-219
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    • 2009
  • Optimum conditions for production of semi-solid Al-Zn-Mg alloy billets was carried out by the Taguchi design method. And, Al-Zn-Mg alloy billets contained Sc (free, 0.1 and 0.3 mass %) were fabricated at optimum conditions. Evolution of microstructure in semi-solid state was investigated through various liquid fractions, holding times and holding temperatures. The Al-Zn-Mg alloy billets reheated at $615^{\circ}C$ during 30min are grain growth and it was fractured due to increasing liquid fraction before quenching. And, during reheating up to $600^{\circ}C$, grain growth of Al-Zn-Mg alloy billets contained Sc (0.1 and 0.3 mass %) was not occurred in comparison with those of Al-Zn-Mg alloy without Sc. It was thought that $Al_3Sc$ phases have a pinning effect in grain boundary and Sc content of 0.1 mass% is able to inhibit grain growth effectively through reheating process.

Schwannoma of the Heart

  • Hwang, Su Kyung;Jung, Sung-Ho
    • Journal of Chest Surgery
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    • v.47 no.2
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    • pp.141-144
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    • 2014
  • We present a case of a 55-year-old woman who complained of chest pain at rest. A mass was detected adjacent to her left atrium. The mass was completely excised, and a pathologic examination revealed it to be a schwannoma. Schwannomas are tumors that originate in the nerve sheath and are rarely detected in the heart. Here, we describe a rare case of primary schwannoma of the left atrium.

Rapid Determination of Imatinib in Human Plasma by Liquid Chromatography-Tandem Mass Spectrometry: Application to a Pharmacokinetic Study

  • Yang, Jeong Soo;Cho, Eun Gi;Huh, Wooseong;Ko, Jae-Wook;Jung, Jin Ah;Lee, Soo-Youn
    • Bulletin of the Korean Chemical Society
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    • v.34 no.8
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    • pp.2425-2430
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    • 2013
  • A simple, fast and robust analytical method was developed to determine imatinib in human plasma using liquid chromatography-tandem mass spectrometry with electrospray ionization in the positive ion mode. Imatinib and labeled internal standard were extracted from plasma with a simple protein precipitation. The chromatographic separation was performed using an isocratic elution of mobile phase involving 5.0 mM ammonium formate in water-5.0 mM ammonium formate in methanol (30:70, v/v) over 3.0 min on reversed-stationary phase. The detection was performed using a triple-quadrupole tandem mass spectrometer in multiple-reaction monitoring mode. The developed method was validated with lower limit of quantification of 10 ng/mL. The calibration curve was linear over 10-2000 ng/mL ($R^2$ > 0.99). The method validation parameters met the acceptance criteria. The spiked samples and standard solutions were stable under conditions for storage and handling. The reliable method was successfully applied to real sample analyses and thus a pharmacokinetic study in 27 healthy Korean male volunteers.

Optimal assessment and location of tuned mass dampers for seismic response control of a plan-asymmetrical building

  • Desu, Nagendra Babu;Dutta, Anjan;Deb, S.K.
    • Structural Engineering and Mechanics
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    • v.26 no.4
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    • pp.459-477
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    • 2007
  • A bi-directional tuned mass damper (BTMD) in which a mass connected by two translational springs and two viscous dampers in two orthogonal directions has been introduced to control coupled lateral and torsional vibrations of asymmetric building. An efficient control strategy has been presented in this context to control displacements as well as acceleration responses of asymmetric buildings having asymmetry in both plan and elevation. The building is idealized as a simplified 3D model with two translational and a rotational degrees of freedom for each floor. The principles of rigid body transformation have been incorporated to account for eccentricity between center of mass and center of rigidity. The effective and robust design of BTMD for controlling the vibrations in structures has been presented. The redundancy of optimum design has been checked. Non dominated sorting genetic algorithm (NSGA) has been used for tuning optimum stages and locations of BTMDs and its parameters for control of vibration of seismically excited buildings. The optimal locations have been observed to be reasonably compact and practically implementable.

A Case of Severe Cough-induced Abdominal Wall Hematoma (심한 기침에 의해 발생한 복벽 혈종 1예)

  • Son, Jun-Hyuk;Baik, Jae-Joong;Yang, Keum-Yeoi;Ryu, Kwang-Won;Joo, Young-Jin;Choi, Seung-Min;Kim, Sang-Cheol;Chung, Yeon-Tae
    • Tuberculosis and Respiratory Diseases
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    • v.51 no.5
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    • pp.462-465
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    • 2001
  • Severe cough may contribute to serious complications such as pneumothorax, pneumomediastinum, rib fracture, subconjunctival hemorrhage, subdural hemorrhage and cough syncope. However abdominal wall hematoma is a rare complication. Because it usually presents with abdomianal pain, abdominal wall hematoma needs to be differentiated from the acute surgical abdomen. A 78-year old woman was admitted with right lower quadrant abdominal pain and a palpable mass for several days. She experienced abdominal pain after violent coughing associated with an upper respiratory tract infection. Abdominal computed tomography revealed an approximately $7{\times}4cm$ sized, ill-defined, soft tissue density lesion in the right lower posterolateral abdominal wall. An abdominal wall hematoma was diagnosed. After admission, she had persistent right lower abdominal pain and an increasing mass. The mass was surgically removed and she was discharged without complications. In summary, when a patient complains of abdominal pain after severe coughing, an abdominal wall hematoma as a differential diagnosis must be considered.

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Identification of Propentofylline Metabolites in Rats by Gas Chromatography/Mass Spectrometry

  • Kwon, Oh-Seung;Ryu, Jae-Chun
    • Archives of Pharmacal Research
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    • v.23 no.4
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    • pp.374-380
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    • 2000
  • Propentofylline (PPF, 3-methyl-1-(5-oxohexyl)-7-propylxanthine) has been reported to be a compound for treatment of both vascular dementia and dementia of the Alzheimer type. The short half-life (about 15 min) of PPF at the terminal elimination phase and poor bioavailability after oral administration of PPF to rabbits (Kim et al., 1992) suggest in part that this drug takes the extensive first-pass metabolism in the liver. In addition, the metabolic pathway for PPF remains unclear. The objective of this experiment is to identify urinary metabolites of PPF in rats. For the identification of the metabolites, rat urine was collected after oral administration of 100${m}g/kg$ PPF. PPF metabolite, 3-methyl-1-(5-hydroxyhexyl)-7-propylxanthine, was synthesized and confirmed by gas chromatography/mass spectroscopy (GC/MS) and $^1H$ nuclear magnetic resonance spectroscopy. The urinary metabolites of PPF were extracted with diethyl ether and identified by electron impact and chemical ionization GC/MS. One urinary metabolite was confirmed to be 3-methyl-1-(5-hydroxyhexyl)-7-propylxanthine by synthesized authentic compound. Several metabolites of monohydroxy- and dihydroxy-PPF were identified based on mass fragmentation of both intact and trimethylsilylated derivatives of PPF metabolites and the novel structure of these metabolites is suggested based on mass spectra.

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Liquid Chromatography-tandem Mass Spectrometry for Quantification of Dioscin in Rat Plasma

  • Kong, Tae Yeon;Ji, Hye Young;Choi, Sang-Zin;Son, Miwon;Lee, Hye Suk
    • Mass Spectrometry Letters
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    • v.4 no.3
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    • pp.55-58
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    • 2013
  • Dioscin is a biologically active steroidal saponin with anticancer and hepatoprotective effects. A rapid, selective, and sensitive liquid chromatographic method with electrospray ionization tandem mass spectrometry was developed for the quantification of dioscin in rat plasma. Dioscin was extracted from rat plasma using ethyl acetate at acidic pH. The analytes were separated on a Halo C18 column using gradient elution of acetonitrile and 0.1% formic acid and detected by tandem mass spectrometry in selected reaction monitoring mode. The standard curve was linear ($r^2$ = 0.998) over the concentration range of 1-100 ng/mL. The lower limit of quantification was 1.0 ng/mL using 50 ${\mu}L$ of plasma sample. The coefficient of variation and relative error for intra- and inter-assay at four QC levels were 1.3 to 8.0% and -5.4 to 10.0%, respectively. This method was applied successfully to the pharmacokinetic study of dioscin after oral administration of dioscin at a dose of 29.2 mg/kg in male Sprague-Dawley rats.

A Study on Rotating Balancing of High-speed spindle by using $ADAMS^(R)$ ($ADAMS^(R)$를 이용한 초고속 스핀들의 회전 밸런싱 (Balancing)에 대한 연구)

  • Cho Y.D.;Chung W.J.;Lee C.M.;Yoon S.H.;Whang Y.K.;Park G.B.
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2005.10a
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    • pp.560-563
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    • 2005
  • According to the demand of the high productivity, the interest of manufacturing skills is growing in industrial society. Especially the high-speed spindle in machining center becomes important these days. The rotating accuracy of the spindle in machining center concerns the centrifugal force. In detail explaining, it is influenced by the unbalance mass. In this study, we could find changes of the vibration caused by condition (increased mass, rotating speed, position) of unbalance mass and verify it using a software - $ADAMS^(R)$ With this study, it will help workers on the spot solve the problems concerning unbalance mass.

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THE ARCHES CLUSTER MASS FUNCTION

  • Kim, Sung-Soo S.;Figer, Donald F.;Kudritzki, Rolf P.;Naharro, F.
    • Journal of The Korean Astronomical Society
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    • v.40 no.4
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    • pp.153-155
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    • 2007
  • We have analyzed H and $K_s$-band images of the Arches cluster obtained using the NIRC2 instrument on Keck with the laser guide star adaptive optics (LGS AO) system. With the help of the LGS AO system, we were able to obtain the deepest ever photometry for this cluster and its neighborhood, and derive the background-subtracted present-day mass function (PDMF) down to $1.3M_{\bigodot}$ for the 5"-9" annulus of the cluster. We find that the previously reported turnover at $6M_{\bigodot}$ is simply due to a local bump in the mass function (MF), and that the MF continues to increase down to our 50 % completeness limit ($1.3M_{\bigodot}$) with a power-law exponent of ${\Gamma}$ = -0.91 for the mass range of 1.3 < M/$M_{\bigodot}$ < 50. Our numerical calculations for the evolution of the Arches cluster show that the ${\Gamma}$ values for our annulus increase by 0.1-0.2 during the lifetime of the cluster, and thus suggest that the Arches cluster initially had ${\Gamma}$ of $-1.0{\sim}-1.1$, which is only slightly shallower than the Salpeter value.