• 월간산업보건
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• s.275
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• pp.29-31
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• 2011

Perchloryl fluoride의 직업적 노출기준 TLV-TWA 3 ppm(13 $mg/m^3$)과 TLV-STEL 6 ppm (25 $mg/m^3$)은 hydrogen fluoride와의 구조 유사성을 근거로 권고하였다. 이 수준은 호흡기계 기관지 자극 가능성을 최소화하는 수준이며 이는 실험동물 연구를 기초하였다. Perchloryl fluoride에 노출된 개, 몰모트, 흰쥐 그리고 생쥐에서 유발된 독성 증상 및 징후는 폐충혈, 부종, 호흡곤란, 청색증 그리고 비장, 간, 신장, 골수에서의 혈철소증이다. TLV-STEL은 폐에 대한 악영향과 플루오르 침착증에 대한 안전을 좀 더 확보하기 위하여 권고하였다. "피부흡수(skin)"와 "감작제(SEN)" 그리고 발암성에 대한 경고주석을 설정하기에는 유용한 자료가 부족하다.

• Korean Journal of Optics and Photonics
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• v.29 no.3
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• pp.99-103
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• 2018

Optical coherence elastography (OCE) is based on optical coherence tomography (OCT), which is a noninvasive, high-resolution, cross-sectional imaging technique. In this paper, we have developed dynamic optical coherence elastography to measure elasticity, a mechanical property of tissue, by phase difference. A piezoelectric actuator was used for sinusoidal mechanical loading of samples. Before applying this method to biomaterial, we assessed the feasibility of OCE with samples of sponge, eraser, and sharp lead. Cross-sectional and phase-difference images of the sample were obtained under sinusoidal loading. The strain rate was calculated from the phase-difference information. To obtain the envelope of the phase-difference oscillations along the horizontal direction, Hilbert transformation was performed at each depth. The elevation of the envelope was represented by color mapping, and we could measure the relative elasticity within the sample by comparing the elevations. Finally, there was an advantage when we calculated the shear rate using self-interference in the sample arm, instead of the interference between sample and reference arms.

• Applied Chemistry for Engineering
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• v.30 no.6
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• pp.698-706
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• 2019

Over the last few decades, there have been a lot of efforts to develop soft actuators, which can be external stimuli-responsive and applied to the human body. In order to fabricate medical soft actuators with a dynamic precision control, the 3D crosslinked poly(acrylic acid) (PAAc)/poly(vinyl alcohol) (PVA)/poly(ethylene glycol) (PEG) hydrogels were synthesized in this study by using a radiation technique without noxious chemical additives or initiators. After irradiation, all hydrogels showed high gel fraction over 75% and the ATR-FTIR spectra indicated that PAAc/PVA/PEG hydrogels were successfully synthesized. In addition, the gel fraction, equilibrium water content, and compressive strength were measured to determine the change in physical properties of PAAc/PVA/PEG hydrogels according to the irradiation dose and content ratio of constituents. As the irradiation dose and amount of poly(ethylene glycol) diacrylate (PEGDA) increased, the PAAc/PVA/PEG hydrogels showed a high crosslinking density and mechanical strength. It was also confirmed that PAAc/PVA/PEG hydrogels responded to electrical stimulation even at a low voltage of 3 V. The bending behavior of hydrogels under an electric field can be controlled by changing the crosslinking density, ionic group content, applied voltage, and ionic strength of swelling solution.

• Applied Microscopy
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• v.42 no.1
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• pp.9-16
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• 2012

The goal of this study was to identify neurotransmitters in endings (p-endings) presynaptic to low-threshold mechanoreceptive vibrissa afferents in the laminae III/IV of cat trigeminal caudal nucleus (Vc). Rapidly-adapting vibrissa afferents were intra-axonally labeled after electrophysiological identification, and postembedding immunogold staining with antisera against ${\gamma}$-aminobutyric acid (GABA) and glycine was performed, followed by quantitative ultrastructural analysis of p-endings presynaptic to the labeled vibrissa afferent terminals. Sixteen p-endings, which are presynaptic to the HRP-labeled vibrissa afferent terminals, were analyzed in this study: Eight p-endings (50%, 8/16) were immunopositive to GABA but immunonegative to glycine (GABA+ p-ending), and remaining 8 p-endings (50%, 8/16) exhibited immunoreactivity to both GABA and glycine. Bouton volume of the p-endings was not significantly different between the two groups. However, the p-endings differed from each other in relative content of GABA and glycine. These findings suggest that low-threshold mechanoreceptive information conveyed through vibrissa afferent at Vc is presynaptically modulated by GABA and/or glycine, and that degree of presynaptic modulation may differ among each vibrissa afferent terminal.

• Applied Microscopy
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• v.39 no.2
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• pp.141-147
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• 2009

The antennae of millipedes have a prominent function in detecting various types of environmental stimuli, and structural modification of the antennae is closely associated with the degree of sense recognition. Although the biological significance of the antennal sensillae to millipedes are widely understood, the structure and function of the antennal sensillae are still not clear and more precise analysis is required. We have analysed the ultrastructural characteristics of the antennal sensillae in a millipede Anaulaciulus koreanus koreanus using field emission scanning electron microscopy (FESEM). According to their morphological and substructural features, we could identify three different types of antennal sensillae as follows: trichoid sensilla (TS), chaetiform sensilla (CS) and basiconic sensilla (BS). The TS on the articles are long, blunt-tipped, almost straight hairs with deep longitudinal grooves in their lower parts whereas, the CS are long, sickleshaped bristles with longitudinal grooves acuminating toward the tip. The BS can be subdivided further into three subtypes which are the large-sized basiconic sensilla ($BS_1$), the small-sized basiconic sensillae ($BS_2$) and the spiniform basiconic sensillae ($BS_3$). The BS between the terminal segment and distal margins of the other segments are clearly discriminated in this species.

• Journal of rehabilitation welfare engineering & assistive technology
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• v.9 no.4
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• pp.265-273
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• 2015

Children with autistic spectrum disorder(ASD) have a strength in visual process and systemizing, and they show interest toward things and machines. Therefore, robots have been suggested as a useful tool for the rehabilitation of the children with ASD. A robot can attract children's interest and attention, and it can provide simplified social stimulus. A robot can be applied repetitively, and programmed for the special needs of an individual child. In this study, we review literature related to the use of robots for the rehabilitation of children with ASD. For this purpose, related literature was searched with the keywords of autism and robot. We selected eleven domestic papers, and analyzed their contents to identify robots, stimulus of robots, experiment process and dependent variables.

• Transactions of the Korean Society of Mechanical Engineers
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• v.15 no.6
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• pp.1967-1974
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• 1991

When the functional electrical stimulation is employed to recover mobility to the plegic, it is very important to understand functions of the selected muscles. I have investigated how a muscle acts to accelerate the body segments, since the body segements are connected by joints so that contraction of a muscle not only rotates the segments to which it is attached but also causes other segments to rotate by creation a reaction force at every joint, which is called the inertial coupling. I found that a single-joint muscle always acts to accelerate the spanned joint in the same direction as the joint torque produced by the muscle. However, a double-joint muscle can act to accelerate the spanned joint in the opposite direction to the joint torque produced by the muscle depending on (1) the body position, (2) the body-segmental parameters, and (3) the type of the movement. Investigating the condition number of the inertia matrix of the body-segmental model gave us some insights into how controllable the body-segmental system is for different values of the factors mentioned above. The results suggested that the upright position is the most undesirable position to independently control the three segments(trunk, thigh and shank) and that the controllability is the most sensitive to variation of the shank length and the trunk mass, which implies that accuracy is required particularly when we estimate these two body-segmental parameters before the paralyzed muscles are innervated by using electrical stimulation.

• Journal of the Korean Society of Radiology
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• v.16 no.6
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• pp.787-797
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• 2022

The purpose of this study was to confirm the reduction of pain and symptom relief of Parkinson's disease by vertically stimulating the spine through the application of a mechanical bed capable of thermal and massage stimulation. For this purpose, after confirming the segmental motion of the spine due to the use of a medical combination stimulation bed for Parkinson's disease patients, VAS, ODI, gait ability, and spiral drawing tests were performed, and the relationship between the variables was identified. In the 10-day visual analog scale and evaluation of low back pain dysfunction, the average trend of decreasing after bed use was confirmed. For walking ability, a decrease in the moving time and an increase in the moving distance were observed. In the spiral drawing test, the mean test time after using bed was significantly lower than before. As a result, it suggested the possibility of using it as an auxiliary method for recovery and pain relief of Parkinson's disease patients due to spinal segmental movement with mechanical heating and massage. However, this study is a preliminary study, and there is a small number of subjects, so additional research is needed that considers the number and condition of future subjects in detail.

• Journal of the korean academy of Pediatric Dentistry
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• v.31 no.2
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• pp.299-303
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• 2004

The conventional drilling method of caries removal makes vibration and thermal stimuli, so that children are afraid of dental treatment. Recently, various non-invasive caries removal techniques of alternatives to traditional methods are introduced and chemo-mechanical caries removal is one of them. $Carisolv^{TM}$ comprises a gel that is composed of three different amino acids and a low concentration of sodium hypochlorite and specially-designed hand instruments. This report describes two cases of dental caries treatment with $Carisolv^{TM}$. The carious dentin was eliminated with $Carisolv^{TM}$ gel with instruments and then composite resin restoration was conducted.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2000.06a
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• pp.1261-1267
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• 2000

외부에서 자극이 가해질 때 상전이(phase transformations)하는 방식으로 대응하는 재료들이 최근 다양하게 연구되고 있다. 예를 들어 형상기억합금은 주변 온도의 변화에 대응하여 그 형상을 변화시키는데 이 과정은 미시적으로는 격자의 형태가 - 예를 들면 정방형 격자에서 입방형격자로 혹은 그 반대로 - 변화하는 과정이다. 강유전체 역시 외부에서 인가되는 전계의 변화에 대응하여 그 격자구조가 변하는데 그와 함께 기계적 변형이 동반하게 된다. 본 논문에서는 상전이를 하는 재료에 적용될 수 있는 1차원 구성방정식을 강유전체의 예를 들어 제시하고 간단한 계산결과를 보이기로 한다. 본 모델을 확장하여 강유전체에서의 분극역전(polarization reversals)에 대한 3차원 유한요소 모델을 개발하고 응용하려는 시도가 이루어지고 있다.