• 한국정밀공학회지
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• 제23권4호
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• pp.124-131
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• 2006

A gerotor pump is suitable for oil hydraulics of machine tools, automotive engines, compressors, constructions and other various applications. Especially the pump is an essential machine element of an automotive engine to feed lubricant oil. The subject of this paper is the theoretical analysis of internal lobe pump whose the main components are the rotors: usually the outer one is characterized by lobes with circular shape, while the inner rotor profile is determined as conjugate to the other. For this reason the first topic presented here is the definition of the geometry of the rotors starting from the design parameters. The choice of these parameters is subject to some limitations in odor to limit the pressure angle between the rotors. Now we will consider the design optimization. The first step is the determination of the instantaneous flow rate as a function of the design parameter. This allows us to calculate three performance indexes commonly used far the study of positive displacement pumps: the flow rate irregularity, the specific flow rate, and the specific slipping. These indexes are used to optimize the design of the pump and to obtain the sets of optimum design parameter. Results obtained from the analysis enable the designer and manufacturer of oil pump to be more efficient in this field, and the system could serve as a valuable one for experts and as a dependable training aid for beginners.

• Journal of Chest Surgery
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• 제34권7호
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• pp.574-577
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• 2001

동성애로 인하여 인간면역결핍 바이러스에 감염된 54세 남자가 발열, 우측흉통을 주소로 응급실로 내원하였다. 흉부단순촬영상 우측 흉막삼출액이 관찰되어 폐쇄식 흉관삽입술을 시행하였으며 흉막액 세균배양검사에서 살모넬라와 대장균이 동정되었고 항생제 투여에도 불구하고 증상 호전이 없어 늑막전폐절제술을 시행하였다. 수술 후에 환자상태는 호전되는 양상이었으나 수술 후 10일째 부분발작을 보여 뇌 단층촬영을 시행하였으며 우측 전두엽과 좌측 전측두엽에 여러 개의 종괴가 관찰되었고 수술 후 12일째 의식이 저하되면서 급성 호흡부전으로 수술 후 14일째 사망하였다.

• 한국지구과학회지
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• 제30권1호
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• pp.1-9
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• 2009

이 논문은 우리나라의 중생대층과 신생대층에서 기록된 6속 22종의 은행류 화석을 최근까지 확립된 고생물학적 지식에 기초하여 재검토하고, 종의 다양성과 엽형 대해 논의하였다. 연구결과 은행류 화석은 중생대에서 4속 8종, 신생대에서 1속 1종으로 각각 재분류되었다. 중생대형 은행류의 엽신은 대부분 가는 열편으로 갈라져 있지만, 신생대형은 부채꼴 모양의 단엽형으로 나타난다.

• ALGAE
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• 제21권4호
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• pp.407-416
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• 2006

Low molecular weight carbohydrates, phycobilin pigments and cell structure using light and transmission electron microscopy were used to describe a new genus of unicellular red algae, Erythrolobus coxiae (Porphyridiales, Porphyrideophyceae, Rhodophyta). The nucleus of Erythrolobus is located at the cell periphery and the pyrenoid, enclosed by a cytoplasmic starch sheath, is in the cell center. The pyrenoid matrix contains branched tubular thylakoids and four or more chloroplast lobes extend from the pyrenoid along the cell periphery. A peripheral encircling thylakoid is absent. The Golgi apparatus faces outward at the cell periphery and is always associated with a mitochondrion. Porphyridium and Flintiella, the other members of the Porphyrideophyceae, also lack a peripheral encircling thylakoid and have an ER-mitochondria-Golgi association. The low molecular weight carbohydrates digeneaside and floridoside are present, unlike both Porphyridium and Flintiella, which have only floridoside. The phycobilin pigments B-phycoerythrin, R-phycocyanin and allophycocyanin are present, similar to Porphyridium purpureum. The cells have a slow gliding motility without changing shape and do not require substrate contact. The ultrastructural features are unique to members of the Porphyrideophyceae and recent molecular analyses clearly establish the validity of this new red algal class and the genus Erythrolobus.

• Journal of Korean Neurosurgical Society
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• 제29권12호
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• pp.1570-1576
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• 2000

Objective : To evaluate objectively the sites of injury in patients with posttraumatic olfactory deficits and to suggest the diagnostic procedure for evaluation of posttraumatic anosmia. Methods : Ten patients with posttraumatic olfactory dysfunction were examined by means of olfactory testing, sinoscopy, contrast filled paranasal sinus computed tomography(contrast filled PNS CT) and magnetic resonance imaging(MRI). Five normal persons without olfactory dysfunction were also evauluated. The aerodynamic patency of olfactory cleft was examined by contrast filled PNS CT. The olfactory system(oflactory bulbs, olfactory tracts, inferior frontal region, hippocampi, or temporal lobes) was investigated in detail with MRI. The difference in the size of the olfactory bulb between normal volunteers and anosmic patients was evaluated by Student's t test. Results : Contrast filled dynamic CT scan was useful method for the evaluation of dynamic patency of the olfactory cleft. Paranasal CT scan of the all anosmic patients showed dynamic reflux of contrast media in olfactory cleft on valsalva maneuver. For the largest cross-sectional area and great height, the difference in olfactory bulb size between normal volunteers and patients was statistically significant(p<0.001) in MRI study. Conclusion : Posttraumatic anosmia was completely evaluated by olfactory testing, sinoscopy, and contrast filled CT scan for differentiation between conductive type and neurogenic type. Neurogenic anosmia was confirmed by perfect localization with MRI study.

• Journal of Korean Neurosurgical Society
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• 제50권1호
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• pp.60-63
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• 2011

Seizure is a foreseeable risk in patients with brain lesion. However, seizure during treating non-brain lesion is not a familiar situation to neurosurgeon. Posterior reversible encephalopathy syndrome (PRES) is a relatively common situation after systemic chemotherapy. The aim of this study is to make neurosurgeons aware of this potential medical problem. A 52-year-old woman with advanced gastric cancer, presented with low back pain due to spinal metastasis at the 4th lumbar vertebra. Ten cycles of chemotherapy with FOLFOX (5-Fluoruracil/Oxaliplatin) had been completed 23 days ago. Two days before the planned operation, a generalized tonic clonic seizure occurred. She did not have a history of hypertension or seizure. The seizure was stopped with lorazepam 4mg. The brain magnetic resonance (MR) imaging showed high signal changes in both parieto-occipital lobes on the T2-weighted images, and these were partially enhanced, suggesting PRES. The surgery was preceded by treatment with an antiepileptic drug. The MR images, taken 1.5 months after the seizure, showed that the lesion was no longer present. At 3 month follow-up, no additional seizure attack occurred without any seizure medication. The possibility of a seizure attack should be considered if the patient has a history of chemotherapy.

• Journal of Korean Neurosurgical Society
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• 제56권4호
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• pp.348-352
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• 2014

High-flow vertebral arteriovenous fistulas (VAVF) are rare complications of cervical spine surgery and characterized by iatrogenic direct-communication of the extracranial vertebral artery (VA) to the surrounding venous plexuses. The authors describe two patients with VAVF presenting with ischemic presentation after C1 pedicle screw insertion for a treatment of C2 fracture and nontraumatic atlatoaxial subluxation. The first patient presented with drowsy consciousness with blurred vision. The diffusion MRI showed an acute infarction on bilateral cerebellum and occipital lobes. The second patient presented with pulsatile tinnitus, dysarthria and a subjective weakness and numbness of extremities. In both cases, digital subtraction angiography demonstrated high-flow direct VAVFs adjacent to C1 screws. The VAVF of the second case occurred near the left posterior inferior cerebellar artery originated from the persistent first intersegmental artery of the left VA. Both cases were successfully treated by complete occlusion of the fistulous portion and the involved segment of the left VA using endovascular coil embolization. The authors reviewed the VAVFs after the upper-cervical spine surgery including C1 screw insertion and the feasibility with the attention notes of its endovascular treatment.

• 대한기계학회논문집B
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• 제22권11호
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• pp.1610-1624
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• 1998

An axisymmetric jet is forced with two helical fundamental waves of identical frequency spinning in opposite directions and an additional axisymmetric sub harmonic wave. The subharmonic component rapidly grows downstream from subharmonic resonance with the fundamental, significantly depending on the initial phase difference. The variations of the subharmonic amplitude with the initial phase difference show cusp-like shapes. The amplification of the sub harmonic results in 'vortex pairing of helical modes'. Furthermore, azimuthal variation of the amplification induces an asymmetric jet cross-section. When the initial subharmonics is imposed with an initial phase difference close to a critical value, the jet-cross section evolves into a three-lobed shape. One lobe is generated by the enhanced vortex pairing and the other two lobes are generated by the delayed vortex pairing. Thus, it is confirmed that the initial phase difference between the fundamental and the subharmonic plays an important role in controlling the jet cross-section.

• Mycobiology
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• 제47권4호
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• pp.401-407
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• 2019

Two new species of the lichen genus Placolecis are discovered in China, namely P. kunmingensis An. C. Yin & Li S. Wang and P. sublaevis An. C. Yin & Li S. Wang. The new combination P. loekoesiana (S.Y. Kondr., Farkas, J.J. Woo & Hur) An. C. Yin is proposed. Placolecis kunmingensis is characterized by having simple, spherical or ellipsoid, hyaline spores, and pear-shaped pycnidia; while P. sublaevis can be distinguished by its thallus forming larger aggregations with slightly flattened lobes at the thallus margin, and urn-shaped pycnidia. Descriptions, a phylogenetic tree and a key are provided for all the known Placolecis species in China.

• Journal of Microbiology
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• 제43권3호
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• pp.266-271
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• 2005

In eukaryotic cells, various proteins are anchored to the plasma membrane through glycosylphosphatidylinositol (GPI). To study the biosynthetic pathways and modifications of GPI, various mutant cells have been isolated from the cells of Chinese hamster ovaries (CHO) supplemented with several exogenous genes involved in GPI biosynthesis using aerolysin, a toxin secreted from gram-negative bacterium Aeromonas hydrophila. Alpha toxin from Gram-positive bacterium Clostridium septicum is homologous to large lobes (LL) of aerolysin, binds GPI-anchored proteins and possesses a cell-destroying mechanism similar to aerolysin. Here, to determine whether alpha toxins can be used as an isolation tool of GPI-mutants, like aerolysin, CHO cells stably transfected with several exogenous genes involved in GPI biosynthesis were chemically mutagenized and cultured in a medium containing alpha toxins. We isolated six mutants highly resistant to alpha toxins and deficient in GPI biosynthesis. By genetic complementation, we determined that one mutant cell was defective of the second subunit of dolichol phosphate mannose synthase (DPM2) and other five cells were of a putative catalytic subunit of inositol acyltransferase (PIG-W). Therefore, C. septicum alpha toxins are a useful screening probe for the isolation of various GPI-mutant cells.