• The korean journal of orthodontics
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• v.51 no.2
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• pp.115-125
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• 2021

Objective: To evaluate the reasons influencing the preferences for a certain type of orthodontic appliance over another among prospective patients (PP) and orthodontists. Methods: A total of 49 PP and 51 orthodontists were asked about their preferences for the following appliances: clear aligners (CA), lingual metallic brackets (LMB), polycrystalline and monocrystalline ceramic brackets, and buccal metallic brackets (BMB). The participants rated the importance of 17 potential reasons that would explain their choices. The reasons that contributed most to these preferences were identified. Non-parametric tests (Fisher's exact, χ2 and Mann-Whitney tests) and multivariate analyses (regression and discriminant analysis) were used to assess the data (α = 0.05). Results: CA and BMB were the most chosen appliances by PP and orthodontists, respectively. LMB was the most rejected option among both groups of participants (p < 0.001). Rates of the importance of pain/discomfort, smile esthetics, finishing details, and feeding/speech impairment showed the highest differences between PP and orthodontists (p < 0.0005). Discriminant analyses showed that individuals who considered treatment time and smile esthetics as more important were more likely to prefer CA, while those who prioritized finishing details and cost were more likely to choose BMB (p < 0.05). Conclusions: Reasons related to comfort and quality of life during use were considered as more important by PP, while those related to the results and clinical performance of the appliances were considered as more relevant by orthodontists.

• Korean Journal of Applied Biomechanics
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• v.18 no.1
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• pp.159-168
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• 2008

The purpose of this study was to analyze the variables of plantar pressure distribution, the COG between Flying Sit Spin(FSS) and Flying Camel Spin(FCS) during a Figure Skating. In order to investigate the two types of spin mechanism in the Korea national of elite women Figure skaters(N=4), this study investigated the phase time, CA(contact area), MF(maximum force) Mean Force, and PP(peak pressure) Mean Force. The data was collected using PEDAR Mobile System which is the pressure distribution measuring devices. The obtained conclusions were as follow: During the two types of spins(FSS and FCS), the FCS is higher than the FSS on the MF(20%BW), PP(20%BW) variables during P4 phase, but the FSS is larger than the FCS in the CA, MF, and PP during P1, P2, P3 phase. Consequently, depend on the COP and the COG locations about the vertical ground reaction vector, the FCS comparatively excelled control of speed feedback than the FSS in the P4 phase.

• Korean Journal of Applied Biomechanics
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• v.30 no.4
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• pp.321-335
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• 2020

Objective: The purpose of this study was to investigate the effect of neck traction and foot type on plantar pressure distribution during walking. Method: Total of 24 data were collected from women working with a computer for more than 6 hours every day. Three groups by foot type were divided: Pes Planus, normal foot, and Pes Cavus. Depending on the foot type and cervical traction, plantar pressure variables were measured; CA, MF, PP, and CT. Each variable was divided into 12 masks. MANOVA was performed for the difference of plantar pressure variables by foot type, and a paired t-test was performed for the cervical traction within groups. Results: The total CA decreased in the Pes Planus (p<.001) and Pes Cavus (p<.05) groups. MF increased in the big toe (p<.01) and 2nd toe (p<.05) of the normal foot, and MF-3rd metatarsal decreased (p<.01). The MF-2nd toe (p<.01) and 3rd toe (p<.05) of Pes Cavus decreased. The PP decreased in 2nd toe (p<.05), 3rd toe (p<.01), and 4th toe (p<.05) of the Pes Cavus. In normal foot, the PP-3rd metatarsal (p<.05) and PP-4th metatarsal (p<.01) reduced. In Pes Planus, PP decreased in the hindfoot (p<.05). In Pes Cavus group wearing a neck-tractor, the CT-hindfoot increased (p<.05). Conclusion: There was a significant change in the plantar pressure change by foot type after neck traction. When walking with a neck-tractor, the heel impact was alleviated in the Pes Planus, and the Pes Cavus showed the smooth and effective propulsion in the push-off. Overall, weight acceptance was effectively performed when walking with neck-traction. It was also found that the neck-tractor corrects the alignment of the neck, thereby creating a more stable gait pattern.

• Proceedings of the Korean Society of Postharvest Science and Technology of Agricultural Products Conference
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• 2003.10a
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• pp.165.2-166
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• 2003

최소 가공 수박의 가공과 유통 중 품질 열화에 있어 가장 중요한 문제는 과육의 조직연화이다. 따라서 본 연구에서는 세포 분리를 제한하고 과실 조직의 경도를 유지시키는데 효과가 있는 것으로 알려져 있는 칼슘제제 중 calcium chloride, calcium lactate, CaO를 처리하여, 최소 가공 수박에서 조직연화로 발생되는 품질저하 억제에 가장 효과적인 칼슘제제를 알아보고자 하였다. 수박의 과육부위를 2cm의 정육면체 형태로 절단한 후, 0.5% calcium chloride, 0.5% calcium lactate, 0.05% CaO용액에 3분 동안 침지시켰다. 그리고 fan을 이용하여 상온에서 30분 동안 draining한 다음 PP tray에 담아 PP film로 sealing하고 $10^{\circ}C$에서 일주일간 저장하며 품질변화를 살펴보았다. 호흡특성은 0.05% CaO 및 0.5% calcium chloride용액을 처리한 구가 호흡률이 가장 낮게 나타났다. 가용성고형분은 처리 직후 처리구의 함량이 무처리구에 비해 다소 낮아지는 경향을 보였으나, 저장기간 중 0.5% calcium chloride 용액처리구는 다른 처리구에 비하여 큰 함량 변화 없이 당도가 일정 수준으로 유지되었다. pH 변화는 0.5% calcium chloride용액 처리구에서 변화가 가장 작았으며, 경도변화 역시 저장 초기값과 비교하였을 때보다 감소가 적게 일어나 다른 처리구에 비하여 연화 저해에 효과가 있는 것으로 확인되었다. 따라서 최소가공 수박에 대해 칼슘제제 중 calcium chloride용액 처리가 품질유지에 가장 효과적임을 알 수 있었다.

• Proceedings of the Polymer Society of Korea Conference
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• 2006.10a
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• pp.290-290
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• 2006

The toughening mechanisms of polypropylene (PP) containing 9.2 vol % of calcium carbonate ($CaCO_{3}$) nanoparticles were investigated using optical microscopy and transmission electron microscopy. Double-notch four-point bending (DN-4PB) Charpy impact specimens were utilized to study the fracture mechanism(s) responsible for the observed toughening effect. A detailed investigation reveals that the $CaCO_{3}$ nanoparticles act as stress concentrators to initiate massive crazes, followed by shear banding in PP matrix. These toughening mechanisms are responsible for the observed improved impact strength.

• Membrane and Water Treatment
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• v.4 no.2
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• pp.143-155
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• 2013

Four membranes were used to separate Chlorella sp. from their culture medium in cross-flow microfiltration (MF) experiments: cellulose acetate (CA), cellulose nitrate (CN), polypropylene (PP) and polyvinylidenefluoride (PVDF). It was found that the hydrophilic CA and CN membranes with a pore size of 1.2 ${\mu}m$ exhibited the best performances among all the membranes in terms of permeation flux. The hydrophobicity of each membrane material was determined by measuring the angle between the water (liquid) and membrane (solid). Contact angle measurements showed that deionized (DI) water had almost adsorbed onto the surfaces of the CA and CN membranes, which gave $0.00^{\circ}$ contact angle values. The PP and PVDF membranes were more hydrophobic, giving contact angle values of $95.97^{\circ}$ and $126.63^{\circ}$, respectively. Although the pure water flux increased with increasing pore diameter (0.8 < 1.2 < 3.0 ${\mu}m$) in hydrophilic CA and CN membranes, the best performance in term of filtration rate for filtering a microalgae suspension was attained by membranes with a pore size of 1.2 ${\mu}m$. The fouled membrane pore sizes and pore blocking were inspected using a scanning electron microscope (SEM). MF with large pore diameters was more sensitive to fouling that contributed to intermediate blocking, where the size of the membrane pores is almost equivalent to that of cells.

• The Korean Journal of Physiology and Pharmacology
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• v.4 no.6
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• pp.445-453
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• 2000

The present investigation tested the hypothesis that the activation of protein kinase G (PKG) leads to a phosphorylation of $Ca^{2+}-activated$ potassium channel $(K_{Ca}\;channel)$ and is involved in the activation of $K_{Ca}$ channel activity in cerebral arterial smooth muscle cells of the rabbit. Single-channel currents were recorded in cell-attached and inside-out patch configurations of patch-clamp techniques. Both molsidomine derivative 3-morpholinosydnonimine-N-ethylcarbamide $(SIN-1,\;50\;{\mu}M)$ and 8-(4-Chlorophenylthio)-guanosine-3',5'-cyclic monophosphate $(8-pCPT-cGMP,\;100\;{\mu}M),$ a membrane-permeable analogue of cGMP, increased the $K_{Ca}$ channel activity in the cell-attached patch configuration, and the effect was removed upon washout of the drugs. In inside-out patches, single-channel current amplitude was not changed by SIN-1 and 8-pCPT-cGMP. Application of ATP $(100\;{\mu}M),$ cGMP $(100\;{\mu}M),$ ATP+cGMP $(100\;{\mu}M\;each),$ PKG $(5\;U/{\mu}l),$ ATP $(100\;{\mu}M)+PKG\;(5\;U/{\mu}l),$ or cGMP $(100\;{\mu}M)+PKG\;(5\;U/{\mu}l)$ did not increase the channel activity. ATP $(100\;{\mu}M)+cGMP\;(100\;{\mu}M)+PKG\;(5\;U/{\mu}l)$ added directly to the intracellular phase of inside-out patches increased the channel activity with no changes in the conductance. The heat-inactivated PKG had no effect on the channel activity, and the effect of PKG was inhibited by 8-(4-Chlorophenylthio)-guanosine-3',5'-cyclic monophosphate, Rp-isomer $(Rp-pCPT-cGMP,\;100\;{\mu}M),$ a potent inhibitor of PKG or protein phosphatase 2A (PP2A, 1 U/ml). In the presence of okadaic acid (OA, 5 nM), PP2A had no effect on the channel activity. The $K_{Ca}$ channel activity spontaneously decayed to the control level upon washout of ATP, cGMP and PKG, and this was prevented by OA (5 nM) in the medium. These results suggest that the PKG-mediated phosphorylations of $K_{Ca}$ channels, or some associated proteins in the membrane patch increase the activity of the $K_{Ca}$ channel, and the activation may be associated with the vasodilating action.

• The Korean Journal of Physiology and Pharmacology
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• v.21 no.2
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• pp.259-265
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• 2017

Excessive influx and the subsequent rapid cytosolic elevation of $Ca^{2+}$ in neurons is the major cause to induce hyperexcitability and irreversible cell damage although it is an essential ion for cellular signalings. Therefore, most neurons exhibit several cellular mechanisms to homeostatically regulate cytosolic $Ca^{2+}$ level in normal as well as pathological conditions. Delayed rectifier $K^+$ channels ($I_{DR}$ channels) play a role to suppress membrane excitability by inducing $K^+$ outflow in various conditions, indicating their potential role in preventing pathogenic conditions and cell damage under $Ca^{2+}$-mediated excitotoxic conditions. In the present study, we electrophysiologically evaluated the response of $I_{DR}$ channels to hyperexcitable conditions induced by high $Ca^{2+}$ pretreatment (3.6 mM, for 24 hours) in cultured hippocampal neurons. In results, high $Ca^{2+}$-treatment significantly increased the amplitude of $I_{DR}$ without changes of gating kinetics. Nimodipine but not APV blocked $Ca^{2+}$-induced $I_{DR}$ enhancement, confirming that the change of $I_{DR}$ might be targeted by $Ca^{2+}$ influx through voltage-dependent $Ca^{2+}$ channels (VDCCs) rather than NMDA receptors (NMDARs). The VDCC-mediated $I_{DR}$ enhancement was not affected by either $Ca^{2+}$-induced $Ca^{2+}$ release (CICR) or small conductance $Ca^{2+}$-activated $K^+$ channels (SK channels). Furthermore, PP2 but not H89 completely abolished $I_{DR}$ enhancement under high $Ca^{2+}$ condition, indicating that the activation of Src family tyrosine kinases (SFKs) is required for $Ca^{2+}$-mediated $I_{DR}$ enhancement. Thus, SFKs may be sensitive to excessive $Ca^{2+}$ influx through VDCCs and enhance $I_{DR}$ to activate a neuroprotective mechanism against $Ca^{2+}$-mediated hyperexcitability in neurons.

• Journal of the Korean Home Economics Association
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• v.28 no.4
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• pp.41-50
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• 1990

Soy protein was isolated from Korean soy bean 'Chang ryub' and chemically modified with succinic anhydride. Functionality of the soy protein isolate(SPI), succinylated SPI(SPPI), and PP590(commercial) at various pH were investigated. The mechanical and sensory properties of soy bean curds made from several mixing ratio of succinylated soy bean milk were observed. The solubility of SPI significantly increased with succinylation. The solubility of PP590 was lower than that of SSPI. The solubility of SPPI increased significantly in 0.03M CaCl2 solution. The emulsifying activity of SSPI increased. On the range of pH above pI the emulsifying activity of PP590 was higher than that of SPI. There was no difference in emulsion stability among the groups. The foam expansion capacity of SPPI increased at higher pH than pI but the foam stability decreased significantly above pH 9. Mechanical texture profile analysis revealed the modified soy bean curds had the lower hardniss, chewiness and cohesiveness with increased modification. The mechanical characteristics of modified soy bean curds revealed generalized Maxwell Model of 7-elements or 5-elements. In sensory evaluation, the hardness, the springiness and acceptability of modified soy bean curds were lower significantly than those of control soy bean curd.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.3
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• pp.602-606
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• 2009

The absorption capacity and initial absorption rate in 5 %, 10%, 15 % and 20% $Na_{2}CO_{3}$ under the constant temperature at $40^{\circ}C$ and the initial absorption rate in mixture of different alkaline salts such as $KHCO_3$, $CaCO_3$ and $K_{2}CO_{3}$ were measured using batch type stirred cell contractor. 10% $Na_{2}CO_{3}$ showed the highest absorption capacity and $Na_{2}CO_{3}$ and $K_{2}CO_{3}$ showed the somewhat increased absorption capacity and initial absorption rate respectively. Further more, we have studied the effect of adding Pz and Pp to $Na_{2}CO_{3}$. The result showed that absorption rate of $CO_2$ was increased by adding these additives.