• Korean Journal of Community Nutrition
• /
• v.7 no.4
• /
• pp.527-538
• /
• 2002

Body antioxidant status is an important factor in the prevention of many chronic diseases caused by oxidative stress, especially in the elderly and is affected by health-related habits, such as smoking, drinking and regular physical activity. The aim of this study was to investigate the relationship between these health-related habits and plasma antioxidant status in the elderly. Plasma antioxidant status was examined by determining plasma levels of antioxidant vitamins (vitamin C, A, E, $\beta$ -carotene), total antioxidant status (TAS) and thiobarbituric acid-reactive substance (TBARS) . The subjects included 225 elderly persons aged over 60 yews (63 males, 162 females) living in the Ulsan area. They were interviewed to collect data on their general characteristics and health behaviors such as smoking, exercise and alcohol consumption by means of questionnaires. Their dietary intakes were obtained by means of semi-quantitative food frequency questionnaires (FFQ) The study population was divided into two or three groups according to their smoking, drinking, and exercise status. The ratio of smoker, drinker and exerciser was 16.7%, 31.0% and 44.2% respectively. The dietary antioxidant vitamin intakes were not significantly different among groups of smoking and drinking status, but tended to be higher in non-smokers and non-drinkers than in smokers and drinkers. Plasma vitamin C and $\beta$ -carotene levels were significantly higher in non-smokers, but Plasma vitamin A and TBARS levels were significantly lower in non-smokers than in smokers. Plasma TAS was not significantly different among the smoking groups, but showed a tendency to decrease with an increase in the number of packyear. Plasma vitamin C and $\beta$ -carotene levels of the non-drinkers were higher than those of drinkers and past-drinkers, but plasma vitamin A, C, E, TAS and TBARS showed no difference among the groups of drinker. All vitamin intakes of the exercisers were slightly higher than those of the non-exercisers, but vitamin C intake was significantly higher in female exercisers than in non-exercisers. Plasma $\beta$ -carotene levels were significantly higher in male exercisers and plasma vitamin A, C, E, TAS and TBARS levels tended to be higher in exercisers than in non-exercisers. These results suggested that change to non-smoker, modulation of alcohol consumption and regular exercise could enhance antioxidant defences against reactive oxygen species and might increase the likelihood of a healthier life span.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.13 no.7
• /
• pp.716-725
• /
• 2002

In this paper, we showed the applicability of power symmetric MSSI(Mid-Span Spectral Inversion) to the long-haul WDM system with the channel interference due to FWM(Four Wave Mixing). And we showed the degree of performance improvement. We used 1 dB EOP(Eye-Opening Penalty) criterion so as to evaluate the degree of compensation dependent on the variation of chirp parameter of optical pulse for the various input power in high speed tansmission system. And we evaluated the maximum input power of channel be able to be the signal to crosstalk noise (SNR) above 20 dB in the transmission link with the channel interference due to FWM. Consequently the proposed MSSI compensation method is capable to transmitting the total 68 WDM channels simultaneously with a 0.4 nm channel spacing and 5.3 dBm maximum input power in a 10 Gbps transmission link. Therefore the proposed power symmetric MSSI compensation method may be very useful for the implementation of long-haul wideband WDM transmission systems with relatively high power and improved performance.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.27 no.2
• /
• pp.170-175
• /
• 2016

In order to transmit baseband signals through frequency dividing devices, we studied the transfer function of the device in the term of the baseband signal distortion. From the analysis, it is shown that the magnitude of the envelope signal is related to the mixer gain and the insertion loss of the low pass filter whilst the phase is the additional function with the 1/2 of the phase delay. For the purpose of the verification of the study, we designed a dynamic frequency divider at 1,400 MHz. The operating frequency range of the device is closely related to the conversion gain of mixers and the amplitude of input signal, and becomes wide as the conversion gain of mixers increases. The designed frequency divider operates between 0.9 GHz and 3.2 GHz, for -14.5 dBm input power. The circuit shows 20 mW power dissipation at $V_{DD}=2.5V$, and the simulation result shows that an amplitude modulated signal at 1,400 MHz with the modulation index of 0.9 was successfully downconverted to 700 MHz.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.24 no.9
• /
• pp.883-891
• /
• 2013

In wireless smart phone charging scenario, the transmitter pad is larger than the size of the receiver pad. Thus, it is important to supply a constant power to the receiver regardless of its location. In this paper, we propose a new method to regulate the receiver's power by adjusting a drain bias of class E power amplifier. The proposed LF-band wireless power transfer system is as follows: a buck converter power supply which is controlled by a pulse width modulation(PWM) IC TL494, a class E amplifier using a low cost IRF510 power MOSFET, a transmitter coil whose dimension is $16cm{\times}18cm$, a receiver coil whose dimension is $6cm{\times}8cm$, and a full bridge rectifier using Schottky diodes. A measured performance show a maximum output power of 4 W and system efficiency of 67 % if we fix the bias voltage. If we adjust the bias voltage, the received power can be maintained at a constant power of 2 W regardless of receiver pad location.

• International Journal of Oral Biology
• /
• v.31 no.4
• /
• pp.113-118
• /
• 2006

In the primary sensory neuron of the mesencephalic trigeminal nucleus (MTN), the peripheral axon supplies a large number of annulospiral endings surrounding intrafusal fibers encapsulated in single muscle spindles while the central axon sends only a few number of synapses onto single ${\alpha}-motoneurons({\alpha}-MNs)$. Therefore, the ${\alpha}-{\gamma}$ linkage is thought to be very crucial in the jaw-closing movement. Spike activity in a ${\gamma}-motoneuron\;({\gamma}-MN)$ would induce a large number of impulses in single peripheral axons by activating many intrafusal fibers simultaneously, subsequently causing an activation of ${\alpha}-MNs$ in spite of the small number of synapses. Thus, the activity of ${\gamma}-MNs$ may be vital for modulation of jaw-closing movements. Independently of such a spindle activity modulated by ${\gamma}-MNs$, somatic depolarization in MTN neurons is known to trigger the oscillatory spike activity. Nevertheless, the trafficking of these spikes arising from the two distinct sources of MTN neurons is not well understood. In this short review, switching among multiple functional modes of MTN neurons is discussed. Subsequently, it will be discussed which mode can support the ${\alpha}-{\gamma}$ linkage. In our most recent study, simultaneous patch-clamp recordings from the soma and axon hillock revealed a spike-back-propagation from the spike-initiation site in the stem axon to the soma in response to a somatic current pulse. The persistent $Na^+$ current was found to be responsible for the spike-initiation in the stem axon, the activation threshold of which was lower than those of soma spikes. Somatic inputs or impulses arising from the sensory ending, whichever trigger spikes in the stem axon first, would be forwarded through the central axon to the target synapse. We also demonstrated that at hyperpolarized membrane potentials, 4-AP-sensitive $K^+$ current ($IK_{4-AP}$) exerts two opposing effects on spikes depending on their origins; the suppression of spike initiation by increasing the apparent electrotonic distance between the soma and the spike-initiation site, and the facilitation of axonal spike invasion at higher frequencies by decreasing the spike duration and the refractory period. Through this mechanism, the spindle activity caused by ${\gamma}-MNs$ would be safely forwarded to ${\alpha}-MNs$. Thus, soma spikes shaped differentially by this $IK_{4-AP}$ depending on their origins would reflect which one of the two inputs was forwarded to the target synapses.

• International Journal of Oral Biology
• /
• v.31 no.4
• /
• pp.127-133
• /
• 2006

[ $H_2O_2$ ], a member of reactive oxygen species (ROS), is known to be involved in the mediation of physiological functions in a variety of cell types. However, little has been known about the physiological role of $H_2O_2$ in exocrine cells. Therefore, in the present study, the effect of $H_2O_2$ on cholecystokinin (CCK)-evoked $Ca^{2+}$ mobilization and amylase release was investigated in rat pancreatic acinar cells. Stimulation of the acinar cells with sulfated octapeptide form of CCK (CCK-8S) induced biphasic increase in amylase release. Addition of $30\;{\mu}M\;H_2O_2$ enhanced amylase release caused by 10 pM CCK-8S, but inhibited the amylase release induced by CCK-8S at concentrations higher than 100 pM. An ROS scavenger, $10\;{\mu}M$ Mn(III)tetrakis(4-benzoic acid)porphyrin chloride, increased amylase release caused by CCK-8S at concentrations higher than 100 pM, although lower concentrations of CCK-8S-induced amylase release was not affected. To examine whether the effect of $H_2O_2$ on CCK-8S-induced amylase release was exerted via modulation of intracellular $Ca^{2+}$ signaling, we measured the changes in intracellular $Ca^{2+}$ concentration $([Ca^{2+}]_i)$ in fura-2 loaded acinar cells. Although $30\;{\mu}M\;H_2O_2$ did not induce any increase in $[Ca^{2+}]_i$ by itself, it increased the frequency and amplitude of $[Ca^{2+}]_i$ oscillations caused by 10 pM CCK-8S. However, $30\;{\mu}M\;H_2O_2$ had little effect on 1 nM CCK-8S-induced increase in $[Ca^{2+}]_i$. ROS scavenger, 1 mM N-acetylcysteine, did not affect $[Ca^{2+}]_i$ changes induced by 10 pM or 1 nM CCK-8S. Therefore, it was concluded that $30\;{\mu}M\;H_2O_2$ enhanced low concentration of CCK-8S-induced amylase release probably by increasing $[Ca^{2+}]_i$ oscillations while it inhibited high concentration of CCK-8S-induced amylase release.

• International Journal of Oral Biology
• /
• v.41 no.3
• /
• pp.133-139
• /
• 2016

The ultrastructural parameters related to synaptic release of endings which are presynaptic to tooth pulp afferent terminals (p-endings) were analyzed to understand the underlying mechanism for presynaptic modulation of tooth pulp afferents. Tooth pulp afferents were labelled by applying wheat-germ agglutinin conjugated horseradish peroxidase to the rat right lower incisor, whereafter electron microscopic morphometric analysis with serial section and reconstruction of p-endings in the trigeminal oral nucleus was performed. The results obtained from 15 p-endings presynaptic to 11 labeled tooth pulp afferent terminals were as follows. P-endings contained pleomorphic vesicles and made symmetrical synaptic contacts with labeled terminals. The p-endings showed small synaptic release-related ultrastructural parameters: volume, $0.82{\pm}0.45{\mu}m^3$ ($mean{\pm}SD$); surface area, $4.50{\pm}1.76{\mu}m^2$; mitochondrial volume, $0.15{\pm}0.07{\mu}m^3$; total apposed surface area, $0.69{\pm}0.24{\mu}m^2$; active zone area, $0.10{\pm}0.04{\mu}m^2$; total vesicle number, $1045{\pm}668.86$; and vesicle density, $1677{\pm}684/{\mu}m^2$. The volume of the p-endings showed strong positive correlation with the following parameters: surface area (r=0.97, P<0.01), mitochondrial volume (r=0.56, P<0.05), and total vesicle number (r=0.73, P<0.05). However, the volume of p-endings did not positively correlate or was very weakly correlated with the apposed surface area (r=-0.12, P=0.675) and active zone area (r=0.46, P=0.084). These results show that some synaptic release-related ultrastructural parameters of p-endings on the tooth pulp afferent terminals follow the "size principle" of Pierce and Mendell (1993) in the trigeminal nucleus oralis, but other parameters do not. Our findings may demonstrate a characteristic feature of synaptic release associated with p-endings.

• Journal of the Korea Institute of Information Security & Cryptology
• /
• v.26 no.3
• /
• pp.679-691
• /
• 2016

As vehicle started to contain many different communication devices, collecting external information became possible in IoT environment. In such environment, remotely controling vehicle is possible when vehicle information is obtained by looking in to vehicle network through smart device. However, android based smart device applications are vulnerable to malicious modulation and redistribution. Modulated android application can lead to vehicle information disclosure that could bring about vehicle control accident which becomes threat to drivers. furthermore, since vehicles today does not contain security methods to protect it, they are very vulnerable to security threats which can cause serious damage to users and properties. In this paper, many different vehicle management android applications that are sold in Google Play has been analyzed. With this information, possible threats that could happen in vehicle management applications are being analysed to prove the risks. the experiment is done on actual vehicle to prove the risks. Also, access control method to protect the vehicle against malicious actions that could happen through external network in IoT environment is suggested in the paper.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.18 no.7
• /
• pp.1557-1564
• /
• 2014

In this paper, we propose a signal detection technique based on the parallel orthogonal matching pursuit (POMP) is proposed for generalized shift space keying (GSSK) systems, which is a modified version of the orthogonal matching pursuit (OMP) that is widely used as a greedy algorithm for sparse signal recovery. The signal recovery problem in the GSSK systems is similar to that in the compressed sensing (CS). In the proposed POMP technique, multiple indexes which have the maximum correlation between the received signal and the channel matrix are selected at the first iteration, while a single index is selected in the OMP algorithm. Finally, the index yielding the minimum residual between the received signal and the M recovered signals is selected as an estimate of the original transmitted signal. POMP with Quantization (POMP-Q) is also proposed, which combines the POMP technique with the signal quantization at each iteration. The proposed POMP technique induces the computational complexity M times, compared with the OMP, but the performance of the signal recovery significantly outperform the conventional OMP algorithm.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2017.05a
• /
• pp.523-526
• /
• 2017

In modern recently technology, 3D-Audio is used to enhance immersion in Virtual Reality. This includes interest of people about VR and AR, which related to the field of computer graphics. In fact, a lot of research has been carried out in recent years into a 3D sound field. However, the existing 3D generator device used for virtual reality does not contain Doppler effect occurred by the sound comes to or leave from a listener, while an angle from the listener and the altitude of the source sound are applied. Therefore, this paper present 3D real sound utilizing Doppler effect with spatial-rotation-speaker. We map the source sound in 3D-space into a real space where a user stays and present 3D real sound by manipulating with rotation angle, phase difference, sound output volume of the sound in 3D-space, according to the location of a virtual source sound. Utilizing both natural Doppler effect of rotating sound that is occurring by spatial-rotation-speaker and artificial Doppler effect generated by frequency-modulation of sound quality could improving the virtual reality for sound condition for perspective listening.