• The Korean Journal of Pain
• /
• v.21 no.1
• /
• pp.11-17
• /
• 2008

Background: Peripheral nerve injury induces up-regulation of the calcium channel alpha2delta (${\alpha}2{\delta}$) subunit and TRPM8 in the dorsal root ganglion (DRG) which might contribute to allodynia development. We investigated the expression of the ${\alpha}2{\delta}$ subunit and TRPM8 in the DRG of sympathetically maintained pain (SMP) and sympathetic independent pain (SIP) rat model. Methods: For the SMP model, the L5 and L6 spinal nerves were ligated tightly distal to the DRG. For the SIP model, the tibial and sural nerves were transected, while the common peroneal nerve was spared. After a 7 day postoperative period, tactile and cold allodynia were assessed using von Frey filaments and acetone drops, respectively. Expression of the ${\alpha}2{\delta}$ subunit and TRPM8 in the L5 and L6 DRG were subsequently examined by a Western blot. Results: There were no significant differences between the two models for the thresholds of tactile and cold allodynia. Expression of the ${\alpha}2{\delta}$ subunit in the ipsilateral DRG to the injury was increased as determined on a Western blot as compared to that in the contralateral or sham-operated DRG of the SMP model, but there was no difference in expression seen with the use of the SIP model. There was no difference in the expression of TRPM8 in the ipsilateral DRG to the injury and the contralateral or sham-operated DRG of either model. Conclusions: Up-regulation of the ${\alpha}2{\delta}$ subunit in injured DRG may play a role that contributes to tactile allodynia development in SMP, but not TRPM8 to cold allodynia after peripheral nerve injury.

• Korean Journal of Veterinary Research
• /
• v.33 no.3
• /
• pp.381-385
• /
• 1993

수의학 및 농업분야에서 널리 사용되고 있는 살충제인 amitraz의 효과를 척출 돼지 자궁근에서 검토하였다. Amitraz($10^{-8}{\sim}10^{-6}M$)는 발정정지기의 자궁근 수축성을 용량의존적으로 증가시켰다. Amitroaz의 이 효과는 yohimbine($10^{-8}{\sim}10^{-7}M$)에 의해 용량의존적으로 차단되었으나, prazosin($10^{-6}M$)에 의해서는 억제되지 않았다. 또한 $Ca^{2+}$-free Tyrode's solution에서나 verapamil($3{\times}10^{-5}M$)의 전처치에 의해서 amitraz의 수축효과는 완전히 억제되었다. 따라서 amitraz에 의한 발정정지기 돼지 자궁근의 수축은 ${\alpha}_2$-adrenoceptor가 중개하며 이 효과는 주로 $Ca^{2+}$ entry blocker에 감수성이 있는 $Ca^{2+}$ channel을 통한 extracellular $Ca^{2+}$ influx의 증가에 의한 것으로 여겨진다.

• Journal of the Korean Chemical Society
• /
• v.7 no.2
• /
• pp.159-164
• /
• 1963

The astatine isotopes produced in $He^3$ bombardment of bismuth were analysed with alpha ionization chamber and 100 channel pulse height analyser. The main product was $At^{209}$ formed by ($He^3$, 3n) reaction. Four other isotopes were also identified. Semi-quantitative calculation of relative yield of each isotope was attempted.

• Proceedings of the Korean Biophysical Society Conference
• /
• 2002.06b
• /
• pp.32-32
• /
• 2002

To understand the functional roles of the neuron-specific $\beta$-subunit of large-conductance calcium-activated potassium ($BK_{Ca}$) channel, we isolate the full-length complementary DNA of $\beta$4-subunit from rat brain library and investigated its effects on the function of $\alpha$-subunit (Slo). The deduced amino acid sequence of rat $\beta$4 (r$\beta$4), 210 amino acids in length, was closely related to those of $\beta$4 subunits in other mammalian species but showed only a limited sequence homology to the other $\beta$-subunits, $\beta$1 to $\beta$3.(omitted)d)

• Journal of Mechanical Science and Technology
• /
• v.20 no.2
• /
• pp.262-270
• /
• 2006

Direct numerical simulations (DNS) of turbulent channel flows up to $Re_{\tau}=1270$ are performed to investigate an elliptic feature and strain rate field on cross sections of coherent fine scale eddies (CFSEs) in wall turbulence. From DNS results, the CFSEs are educed and the strain rate field around the eddy is analyzed statistically. The principal strain rates (i.e. eigenvalues of the strain rate tensor) at the CFSE centers are scaled by the Kolmogorov length $\eta$ and velocity $U_k$. The most expected maximum (stretching) and minimum (compressing) eigenvalues at the CFSE centers are independent of the Reynolds number in each $y^+$ region (i. e. near-wall, logarithmic and wake regions). The elliptic feature of the CFSE is observed in the distribution of phase-averaged azimuthal velocity on a plane perpendicular to the rotating axis of the CFSE $(\omega_c)$. Except near the wall, phase-averaged maximum $(\gamma^{\ast}/\gamma_c^{\ast})$ and minimum $(\alpha^{\ast}/\alpha_c^{\ast})$ an eigenvalues show maxima on the major axis around the CFSE and minima on the minor axis near the CFSE center. This results in high energy dissipation rate around the CFSE.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.28 no.7C
• /
• pp.678-687
• /
• 2003

8SQAM(8-state Superposed Quadrature Amplitude Modulation) being a new modem technique for use in power and bandwidth limited digital communication system generates output signals which have a mか and continuous phase transition and a reduced envelope fluctuation by keeping correlation between amplitudes and phases of two subsequent symbols. Also, 8SQAM signal is free of inter-symbol interference(ISI), and has a compact power spectrum. Accordingly 8SQAM, as compared with a conventional 8PSK, is influenced a little by inter-modulation(IM), inter-symbol interference(ISI) and adjacent channel interference(ACI) in a nonlinearly amplified multi-channel(SCPC-FDMA) environment. In this paper, the performance of 8SQAM system in a nonlinearly amplified multi-channel interference environment is analyzed via computer simulation The simulation result shows that 8SQAM outperforms 8PSK with roll-off value of $\alpha$ = 0.3 by 2.7dB in CNR to maintain BER=1$\times$10$^{-4}$ when input back-off(IBO) of HPA is 1dB and channel space is 41.7% of the data bit rate(i.e., spectral efficiency = 2.40b/s/Hz).

• Proceedings of the Optical Society of Korea Conference
• /
• 1996.09a
• /
• pp.96-96
• /
• 1996

• Proceedings of the Korean Society of Developmental Biology Conference
• /
• 2003.10a
• /
• pp.100-100
• /
• 2003

Pluripotent embryonic stem (ES) cells differentiate spontaneously into beating cardiomyocytes via embryo-like aggregates. We describe the use of mouse embryonic stem (mES03) cells as a reproducible differentiation system for cardiomyocyte. To induce cardiomyocytic differentiation, mES03 cells were dissociated and allowed to aggregate (EB formation) at the presence of 0 75% dimethyl sulfoxide (DMSO) for 4 days and then another 4 days without DMSO (4+/4-). Thus treated EBs were plated onto gelatin-coated dish for differentiation. Spontaneously contracting colonies which appeared in approximately 4-5 days upon differentiation. Expression of cardiac-specific genes were determined by RT-PCR. Rebust expression of myosin light chain (MLC-2V), cardiac myosin heavy chain $\alpha$, cardiac muscle heavy polypeptide 7 $\beta(\beta$-MHC), cardiac transcription factor GATA4 and skeletal muscle-specific ${\alpha}_1$-subunit of the L-type calcium channel (${\alpha}_1 CaCh_{sm}$) were detected as early as 8 days after EB formation, but message of cardiac muscle-specific $\alpha$$_1$-subunit of the L-type calcium channel (${\alpha}_1$CaCh) were revealed at a low level. Strikingly, the expression of atrial natriuretic factor (ANF) was not detected. When spontaneous contracting cell masses were examined their electrophysiological features by patch-clamp technique, it showed ventricle-like action potential 17 days after the EB formation. This study indicates that mES03 cell-derived cardiomyocytes displayed biochemical and electrophysiological properties of cardiomyocytes and DMSO enhanced development of cardiomyocytes in 4+/4- method.

• Proceedings of the KSAR Conference
• /
• 2003.06a
• /
• pp.76-76
• /
• 2003

Pluripotent embryonic stem cells can differentiate into beating cardiomyocytes with proper culture conditions and stimulants via embryo-like aggregates. We describe here the use of mouse embryonic stem (mES03) cells as a reproducible differentiation system for cardiomyocyte. mES03 cells growing in colonies were dissociated and allowed to re-aggregated in suspension [embryoid body (EB) formation〕. To induce cardiomyocytic differentiation, cells were exposed to 0.75% dimethyl sulfoxide (DMSO) during EB formation for 4 days and then another 4 days without DMSO (4+/4-). Thus treated EB was plated onto gelatin-coated dishes for differentiation. Spontaneously contracting colonies which appeared in approximately 4~5 days upon differentiation were mechanically dissected, enzymatically dispersed, plated onto coverslips, and then incubated for another 48~72 hrs. By RT-PCR, robust expression of cardiac myosin heavy chain $\alpha$, cardiac muscle heavy polypeptide 7 $\beta$($\beta$-MHC), cardiac transcription factor GATA4, and skeletal muscle-specific $\alpha$$_1$-subunit of the L-type calcium channel ($\alpha$$_1$CaC $h_{sm}$ ) were detected as early as 8 days after EB formation, but message of cardiac muscle-specific $\alpha$$_1$-subunit of the L-type calcium channel ($\alpha$$_1$CaCh) were reveled at a low level. In contrast, expression of myosin light chain (MLC-2V) and atrial natriuretic factor (ANF) were not detected during EB formation for 8 days. However, a strong expression of the atrial-specific ANF gene was expressed from day 8 onward, which were remained constant in EB. (cardiac specialization and terminal differentiation stage). Electrophysiological examination of spontaneously contracting cells showed ventricle-like action potential 17 days after the EB formation. This study indicates that mES03 cell-derived cardiomyocytes via 4+/4- protocol displayed biochemical and electrophysiological properties of subpopulation of cardiomyocytes.

• Journal of Biomedical Engineering Research
• /
• v.29 no.1
• /
• pp.17-24
• /
• 2008

The aim of this paper is to report our preliminary results of investigating the spatial focalization of Zen-meditation EEG (electroencephalograph) in alpha band (8-13 Hz). For comparison, the study involved two groups of subjects, practitioners (experimental group) and non-practitioners (control group). To extract EEG alpha rhythm, wavelet analysis was applied to multi-channel EEG signals. Normalized alpha-power vectors were then constructed from spatial distribution of alpha powers, that were classified by Fuzzy C-means based algorithm to explore various brain spatial characteristics during meditation (or, at rest). Optimal number of clusters was determined by correlation coefficients of the membership-value vectors of each cluster center. Our results show that, in the experimental group, the incidence of frontal alpha activity varied in accordance with the meditation stage. The results demonstrated three different spatiotemporal modules consisting with three distinctive meditation stages normally recognized by meditation practitioners. The frontal alpha activity in two groups decreased in different ways. Particularly, monotonic decline was observed in the control group, and the experimental group showed increasing results. The phenomenon might imply various mechanisms employed by meditation and relaxation in modulating parietal alpha.