• Bulletin of the Korean Chemical Society
• /
• v.34 no.8
• /
• pp.2425-2430
• /
• 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.

• Tuberculosis and Respiratory Diseases
• /
• v.51 no.5
• /
• pp.462-465
• /
• 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.

• Structural Engineering and Mechanics
• /
• v.26 no.4
• /
• pp.459-477
• /
• 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.

• Archives of Pharmacal Research
• /
• v.23 no.4
• /
• pp.374-380
• /
• 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.

• Mass Spectrometry Letters
• /
• v.4 no.3
• /
• pp.55-58
• /
• 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.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2005.10a
• /
• pp.560-563
• /
• 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.

• Bulletin of the Korean Chemical Society
• /
• v.35 no.8
• /
• pp.2585-2588
• /
• 2014

• Journal of The Korean Astronomical Society
• /
• v.40 no.4
• /
• pp.153-155
• /
• 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.

• Particle and aerosol research
• /
• v.8 no.1
• /
• pp.29-35
• /
• 2012

The Faraday cup electrode of different size has been developed and evaluated to investigate the diffusion effect of particles by Brownian motion in a particle beam mass spectrometer(PBMS). Particles which focused and accelerated by aerodynamic lens are charged to saturation in an electron beam, and then deflected electrostatically into a Faraday cup detector for measurement of the particle current. The concentration of particles is converted from currents detected by Faraday cup. Measurements of particle current as a function of deflection voltage are combined with measured relationships between particle velocity and diameter, charge and diameter, and mass and diameter, to determine the particle size distribution. The particle currents were measured using 5, 10, 20, 40 mm sized Faraday cup that can be move to one direction by motion shaft. The current difference for each sizes as a function of position was compared to figure out diffusion effect during transport. Polystyrene latex(PSL) 100, 200 nm sized standard particles were used for evaluation. The measurement using 5 mm sized Faraday cup has the highest resolution in a diffusion distance and the smaller particles had widely diffused.

• The Bulletin of The Korean Astronomical Society
• /
• v.42 no.1
• /
• pp.37.2-37.2
• /
• 2017

The gravitational radiation capture between unequal mass black holes without spins is investigated with numerical relativistic simulations, and compared with the Post-Newtonian approximations. The parabolic approximation which assumes that the gravitational radiation from a weakly hyperbolic orbit is the same as that from the parabolic orbit is adopted. Using the radiated energies from the parabolic orbit simulations, we have obtained the impact parameters (b) of the gravitational radiation captures for weakly hyperbolic orbits with respect to the initial energy. The most energetic encounters occur around the boundary between the direct merging and the fly-by orbits, and we find that several percent of the total ADM initial energy can be emitted at the peak. The equal mass BHs emit more energies than unequal mass BHs at the same initial orbital angular momentum in the case of the fly-by orbits. The impact parameters obtained with numerical relativity deviate from those in Post-Newtonian when the encounter is very strong ($b{\leq}100M$), and the deviations are more conspicuous at the high mass ratio.