• 한국산학기술학회논문지
• /
• 제19권2호
• /
• pp.50-55
• /
• 2018

지진은 예보가 거의 불가능하고 짧은 시간동안 일어나 지진이 발생할 때 적극적인 대처를 할 시간적인 여유가 거의 없어 다른 자연재해에 비해 인명피해와 재산피해가 많이 발생한다. 최근 전 세계적으로 지진이 빈번하게 발생하고 있다. 이와 같이 지진의 증가에 따라 구조물의 안전성 확보에 대한 연구가 활발히 진행되고 있지만 상대적으로 비구조요소인 전기 시설 등에 대한 연구는 미비한 실정이다. 그리고 현재 국내의 전기설비는 지진에 대한 안전설계를 하지 않는 경우가 많아 지진이 발생했을 때 손상에 매우 취약하다. 따라서 본 연구에서는 ABAQUS를 통해 실제 수배전반과 유사하도록 모델링을 하였고 자연지진파를 이용하여 3D 동적비선형해석을 수행하였다. 송변전설비 내진설계 실무지침서의 지진구역I과 보통지반암 조건에 따르면 기능수행수준의 최대응답가속도는 0.157g이다. 하지만 본 연구에서 일반적인 수배전반에 대한 해석결과의 0.1g에서 한계상태 도달비율은 30%로 안전하다고 볼 수 없다. 그리고 해석결과를 통해 지진취약도를 도출하고 분석하였다. 도출된 지진취약도는 수배전반의 한계상태를 판별하는 정량적 근거로 제시하고 이와 관련된 연구의 기초자료로 활용되는데 목적을 가지고 있다.

• 치과방사선
• /
• 제24권1호
• /
• pp.67-77
• /
• 1994

The purpose of this study was to investigate the irradiatiion effects on the capillary and endothelial cell in the submandibular gland. Sprague-Dawley strain male rats were singly irradiated to their neck region with the dose of 5Gy by 6MV X-irradiation and sacrificed on the 6 hours, 12 hours, 1, 3, 7, and 14days after irradiation. The authors observed the histological changes of the capillary at H & E and PAS staining under a light microscope, and also observed the ultrastructural changes of the endothelial cell using a transmission electron microscope. The obtaining results were as follows: 1. In the light microscopic examination, the capillary density was slightly increased on the 1day after irradiation, and increased until the 7 days after irradiatiion. After then, capillary density was apparently decreased. 2. The reaction to PAS staining at acinar cells was decreased on the 6 hours after irradiation, and recovered on the 7days after irradiation. But reaction was decreased on the 14days after irradiation agan, after then, gradually recovered with days. 3. In the transmission electron microscopic examination, mild proliferation of cytoplasmic process of the endothelial cell and reduction in luminal size were observed just after irradiation. After then, nuclear degeneration, marked proliferation of cytoplasmic process, thickened basal lamina, and numerous cytoplasmic vesicles were observed on the 1day after irradiation. These changes were recovered to normal on the 14days after 5Gy group, but not with 10Gy irradiation group. And destruction of endothelial cell and loss of basal lamina were not observed in both groups. 4. From the above results, reduction in luminal size, proliferation of cytoplasmic process and thickening of basal lamina were observed as the irradiation effects on the capillary and endothelial cell of the submandibular gland. And also, these changes may induce increase in capillary number and endothelial permeability by means of increase of cytoplasmic vesicle formation. The changes appeared earlier and more prominent in 10Gy irradiated group than in 5Gy irradiated group.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
• /
• 제33권4호
• /
• pp.340-349
• /
• 2007

Free flap transplantation with microvascular anastomosis has been successfully performed by development of surgical technique, materials and postoperative monitoring equipments of flap. But success rate of microvascular anastomosis is influenced by various factors, and failure rate is about 5-10%. The most influential factor for success rate is surgical technique and other factors that influence failure of microvascular anastomosis are ischemic time of free flap, thrombus formation of anastomosis region and vascular spasm. In this study, vascular patency and thrombus formation in experimental micro-venous anastomosis, and endothelial repair were observed with histologic analysis, scanning electron microscopy, transmission electron microscopic examination. The results were obtained as follows: 1. In vascular patency test in 30 minute and 7 days after micro-venous anastomosis with heparin irrigation, all of 12 anastomosis site were good vascular patency. 2. In thrombus formation in 2 weeks group(Experimental I), 2 site of 6 cases were observed thrombus, and in 4 weeks group(Experimental II), 1 site of 6 cases were observed thrombus. 3. In histologic examination, normal vein(Control Group) showed continued internal elastic lamina, well formed thick smooth muscle layer and connective tissue. The group of 2 weeks after microvenous anastomosis(Experimental I) showd locally recovered internal lamina, discontinued internal lamina, disorganized smooth muscle cells and granulation tissue around suture silk. In the group of 4 weeks after micro-venous anastomosis(Experimental II), anastomosis site showed almostly continued internal lamina, disorganized smooth muscle cells and cicartrized tissue around suture silk. 4. In scanning electron microscope examination in 2 weeks(Experimental I) after micro-venous anastomosis, mesh fibrin formation showed near to endothelial cells, and in 4 weeks after micro-venous anastomosis(EXperimental II), numerous blood cells and fibrin mesh formation was seen associated with irregular endothelial cell arrangement. 5. In transmission electron microscope examination in 2 weeks after micro-venous anastomosis(Experimental I), irregular arrangement of smooth muscle cells was seen adjacent to collagenized tissue around suture silk. In 4 weeks after micro-venous anastomosis(Experimental II), denuded venous wall composed of relatively well arranged smooth muscle cells was covered by endothelial cells, but fibroblast cells and foreign body giant cells near to suture silk was remained. From the results obtained in this study, results of good vascular patiency and anti-thrombotic effect of heparin were obtained as a local irrigation solution, and repair of venous endothelial cell was observed in 2 weeks after micro-venous anastomosis.

• Applied Microscopy
• /
• 제37권4호
• /
• pp.249-258
• /
• 2007

이자섬은 이자를 구성하는 외분비조직에 둘러싸여 존재하는 내분비세포의 집단으로, 이자섬에서 분비되는 인슐린은 $\beta$세포에서 분비되는 호르몬이며, 세포질의 리보좀에서 합성되고 골지체를 경유하여 세포질로 방출되는 기작을 가지고 있다. 충분한 양의 이자섬 이식은 인슐린 의존형 당뇨병인 제1형 당뇨병에서 정상혈당을 회복시키고, 당뇨 합병증을 방지할 수 있는 치료방법으로 사용되고 있다. 하지만 당뇨병 환자에게 이식을 위한 이자섬의 양에 비해 공여자로부터 증여된 이자섬의 양은 제한적이다. 이러한 문제점은 이자섬의 증식으로 연구되고 있으나, 배양된 이자섬이 정상 조직내의 이자섬과 형태적 기능적으로 동일한 것인지에 관한 연구는 미비하였다. 따라서 본 연구에서는 분리된 이자섬과 배양된 이자섬을 구성하는 세포들의 내부구조의 변화를 주사전자현미경, 투과전자현미경을 이용하여 세포의 미세구조를 확인하고, 인슐린 항체를 이용한 $\beta$세포 내의 인슐린 분포양상을 확인하여 다음과 같은 결과를 얻었다. 분리된 이자섬의 $\beta$세포는 일반적인 핵 미토콘드리아, 세포질세망 그리고 인슐린 과립이 분포하고, 배양된 이자섬 $\beta$세포의 경우 분리된 이자섬에 비하여 일반적인 핵의 모습과 부피가 증가한 세포질과 미토콘드리아, 세포질세망 그리고 골지체의 발달이 이루어지는 것으로 관찰되었다. 인슐린 과립의 경우 분리된 이자섬에 비해 감소하며, 세포막 주위에 분포하는 것으로 관찰되었다. 배양된 이자섬에서 관찰되는 인슐린 과립 분포의 변화, 세포질세망의 증가, 골지체의 발달은 배양된 이자섬 $\beta$세포의 인슐린 생성 분비 기능의 향상과 부피의 증가가 이루어지기 위한 세포 내부의 형태적 변화가 이루어지는 것으로 추측된다.

• 농촌의학ㆍ지역보건
• /
• 제16권2호
• /
• pp.154-164
• /
• 1991

Albendazole is a broad spectrum anthelmintics with high activity against intestinal nematodes as well as tremtodes and cestodes infections. But so far wormicidal effect of albendazole against Paragonimus westermani is uncertain. The present study undertaken to observe the morphological changes of Paragonimus westermani which was obtained from experimentally infected with metacercariae isolated from Cambaroides similis and 9 of them were given albendazole 2 doses of 25mg/kg daily for the 2 days and 4 days from the day of 20 weeks after infection. The Paragonimus werms were collected from the lung of the cats which were autopsied at 24 hours after treatment. The fine structures of the collected worms were studied by means of scanning and transmission electron microscopy. The findings of the observations were compared with those of untreated worms. The results are as follows : 1) In the scanning electron microscopic(SEM) observations, the worms obtained from 2 days treated group showed many blebs which were formed on the surface of damaged tegument in between two suckers. Protrusion of oral sucker typically observed and surrounding tegumental ridges were damaged. 2) The worms obtained from 4 days treated group showed marked contraction revealing half size of normal worms. 3) The transmission electronmicroscopic(TEM) observations indicated that large blebs of irregular shapes were formed by the destruction of tegumental ridge of tegumental syncytium and also showed degeneration of mitochondriae. 4) Destruction of tegumental syncytium formation of blebs were usually observed in the ventral side of the worms. 5) Differentiation of tegumental layer and basement layer muscular layer and parenchymal layer around two suckers of worms obtained at 4 days treated group was difficult. 6) Many host cells invaded and destroyed the degenerated tegument by the occurrence of blebs or the exposed muscular layer of the worm after exfoliation of the tegument.

• 대한방사선기술학회지:방사선기술과학
• /
• 제39권4호
• /
• pp.623-630
• /
• 2016

방사선 피폭에 의한 간조직의 장해는 경화성 위축으로 복수가 발생하고 황달과 피로감이 수반된다. 이러한 장해에는 간세포의 형태학적 변화가 동반되고 소기관들의 손상이 연관되어 있다. 본 연구는 이러한 소기관들의 형태적 손상을 알아보고자 하였다. 특히 에너지 대사와 관련된 미토콘드리아와 세포질그물 핵막을 중심으로 관찰하였으며, 방사선 방어제 연구와 병행하였다. 방어제는 혈류 증가 작용이 있는 알리인을 투여하였다. 세포 관찰은 투과전자현미경을 활용하였다. 실험결과, 7 Gy 전신 조사에서 간세포의 핵막이 비후되고, 소기관들 주변에 염증성 변화가 관찰되었다. 20일 경과된 세포에서는 과산화소체와 미토콘드리아 막이 손상되었고 세포질에서 공포가 확인되었다. 30일 경과된 세포에서는 거대한 지방세포들이 관찰되었고. 조면소포체에는 리보솜이 분리된 것을 확인하였다. 알리인 투여 후 간세포에서는 핵막 주변에 많은 수의 조면소포체들이 선명하게 관찰되었고 핵막도 비후되지 않았다. 세포질에는 공포화되거나 염증성 증후들이 관찰되지 않았다. 미토콘드리아의 막손상도 없었으며 글리코겐도 정상적으로 확인되었다. 따라서 일부 방어효과가 있는 것으로 확인되었다.

• 한국통신학회논문지
• /
• 제31권10A호
• /
• pp.1003-1013
• /
• 2006

IEEE802.11g VoWLAN (Voice over Wireless LAN) 단말기는 802.11b 전용 단말기에 비해 통화시간이 30 % 이상 감소하는 문제점이 있어 통화시간이 문제로 대두되고 있다. 일반적으로, 802.11g에서는 멀티캐리어 방식인 OFDM (Orthogonal Frequency Division Multiplexing) 변조방식을 사용하여 54 Mbps속도로 전송하기 때문에 기존의 802.11b MAC (Medium Access Control) 전송방식과 비교하여 통화시간을 만족시키는 것이 어렵다. 본 논문에서는 802.11g 규격을 적용한 단말기에서 통화중 Power Save 방법으로 Holdover Time을 처음으로 제안하므로 통화시간을 만족시킨다. 다만, 통화 단말기 수 증가에 따른 네트워크 혼잡으로 경합 창 (contention window)이 많이 발생하여, Back-off 수 증가로 인한 통화품질(QoS)의 문제가 발생하지만, QoS 해결 방안으로 다운 링크 시 802.11 G.711 Sequence Number를 단말기 MAC 단에서 분석하여 손실율에 따른 Holdover Time을 가변 하는 방법을 제안하므로 이 문제를 해결한다. 802.11b/g 소비전류 분석과 통화 단말기 증가에 따른 네트워크 혼잡에 의한 MAC 파라미터 성능을 분석하며, VQT장비와AiroPeek를 이용하여 실제적인 데이터를 분석한다.

• 대한화장품학회지
• /
• 제46권2호
• /
• pp.133-145
• /
• 2020

본 연구는 용해도가 낮은 수용성 활성물질인 바이오틴(biotin)의 안정화 및 용해도 증가를 목적으로 나노리포좀을 활용하였다. 이번 실험을 통해 바이오틴 나노리포좀의 안정성에 pH가 큰 영향을 준다는 사실을 확인할 수 있었으며, pH 상승이 바이오틴 활성에 튼 영향을 미치지 않음을 확인하였다. 또한 제타사이저(zetasizer)로 입자크기, 제타전위(zeta potential) 및 다분산지수(polydispersity index)를 측정하여 안정성을 평가하였다. 입자크기는 평균 100 ~ 250 nm, 제타전위 -80 ~ -30 mV로 나노리포좀 제조가 가능함을 확인하였다. 바이오틴 나노리포좀 내의 바이오틴 캡슐화율(capsulation efficiency)을 측정하기 위해 dialysis membrane method (DMM)를 이용하여 평가하였으며, 이를 통해 알지닌을 첨가시킨 바이오틴 나노리포좀이 일반 바이오틴 나노리포좀보다 캡슐화율이 5 배 높은 것으로 측정되었다. 바이오틴 나노리포좀의 경피흡수율을 측정하기 위해 in vitro franz diffusion cell method를 통해 확인하였으며, cryogenic transmission electron microscopy (cryo - TEM)을 통해 바이오틴 나노리포좀이 잘 형성되었는지 확인하였다. 본 논문을 통하여 모발건강과 밀접한 관계가 있는 것으로 소개된 바이오틴을 약물전달체(drug delivery carrier)인 나노리포좀에 캡슐화시켜 기존의 낮은 용해도 및 석출되는 문제를 보완한 바이오틴 나노리포좀을 만들 수 있음을 확인하였다.

• 한국임상수의학회지
• /
• 제41권2호
• /
• pp.71-78
• /
• 2024

Changes in elimination behavior, including urination and defecation, are common clinical signs of numerous disorders in cats. Therefore, this study attempted to automatically measure the elimination behavior of cats using the litter box and develop an early warning system for the guardian in case of abnormalities. To construct an early warning system for abnormal changes through cat elimination behavior, it consisted of a litter box, an automatic sensor for data collection and data wifi transmission, a server for data analysis, and a mobile phone app for result transmission and early warning. To establish the reference interval (RI), the elimination behavior was monitored for more than 2 weeks using a motion sensor within a litter box in 37 healthy cats and 19 diseased cats. The data were expressed as daily total visits, daily total stay duration, average stay duration per elimination, weekly total visits, and weekly total stay duration. Healthy cats showed median daily total visits of 3 times/day (RI 1.0-7.0) and daily total stay duration of 192 s/day (RI 8.0-452.0). For weekly data, the median total visits were 20 times/week (RI 3.0-35.25) and the median total stay duration was 1,147 s/week (RI 80.0-2,249.5). The average stay duration per elimination was 59 s/elimination (RI 4.67-132.0). Diseased cats showed more frequent elimination behavior than healthy cats (p < 0.001). Otherwise, for each elimination, diseased cats had shorter stay durations than healthy cats (p < 0.001). This study established the RIs of elimination behavior parameters (frequency and duration) in healthy cats. The present study might help guardians and veterinarians detect changes in elimination behaviors in diseased cats at an early stage.

• The Korean Journal of Physiology and Pharmacology
• /
• 제1권6호
• /
• pp.625-637
• /
• 1997

Calcium ions are implicated in a variety of physiological functions, including enzyme activity, membrane excitability, neurotransmitter release, and synaptic transmission, etc. Calcium antagonists have been known to be effective for the treatment of exertional angina and essential hypertension. Selective and nonselective voltage-dependent calcium channel blockers also have inhibitory action on the acute and tonic pain behaviors resulting from thermal stimulation, subcutaneous formalin injection and nerve injury. This study was undertaken to investigate the effects of iontophoretically applied $Ca^{++}$ and its antagonists on the responses of WDR (wide dynamic range) cells to sensory inputs. The responses of WDR cells to graded electrical stimulation of the afferent nerve and also to thermal stimulation of the receptive field were recorded before and after iontophoretical application of $Ca^{++}$, EGTA, $Mn^{++}$, verapamil, ${\omega}-conotoxin$ GVIA, ${\omega}-conotoxin$ MVIIC and ${\omega}-agatoxin$ IVA. Also studied were the effects of a few calcium antagonists on the C-fiber responses of WDR cells sensitized by subcutaneous injection of mustard oil (10%). Calcium ions and calcium channel antagonists ($Mn^{++}$, verapamil, ${\omega}-conotoxin$ GVIA & ${\omega}-agatoxin$ IVA) current-dependently suppressed the C-fiber responses of WDR cells without any significant effects on the A-fiber responses. But ${\omega}-conotoxin$ MVIIC did not have any inhibitory actions on the responses of WDR cell to A-fiber, C-fiber and thermal stimulation. Iontophoretically applied EGTA augmented the WDR cell responses to C-fiber and thermal stimulations while spinal application of EGTA for about $20{\sim}30\;min$ strongly inhibited the C-fiber responses. The augmenting and the inhibitory actions of EGTA were blocked by calcium ions. The WDR cell responses to thermal stimulation of the receptive field were reduced by iontophoretical application of $Ca^{++}$, verapamil, ${\omega}-agatoxin$ IVA, and ${\omega}-conotoxin$ GVIA but not by ${\omega}-conotoxin$ MVIIC. The responses of WDR cells to C-fiber stimulation were augmented after subcutaneous injection of mustard oil (10%, 0.15 ml) into the receptive field and these sensitized C-fiber responses were strongly suppressed by iontophoretically applied $Ca^{++}$, verapamil, ${\omega}-conotoxin$ GVIA and ${\omega}-agatoxin$ IVA. These experimental findings suggest that in the rat spinal cord, L-, N-, and P-type, but not Q-type, voltage-sensitive calcium channels are implicated in the calcium antagonist-induced inhibition of the normal and the sensitized responses of WDR cells to C-fiber and thermal stimulation, and that the suppressive effect of calcium and augmenting action of EGTA on WDR cell responses are due to changes in excitability of the cell.