• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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• v.8 no.1
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• pp.49-53
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• 1997

Aberrations in VOT measures in apraxia of speech are indicative of speech motor programming impairment. In English, overlaps of VOT between voiceless and voiced plosives have been frequently observed in patients with apraxia of speech. Unlike English, Korean plosives constitute trichotomy in terms of manner of production, that is, voiceless aspirated /p', t', k'/ ; voiceless or voiced, weakly aspirated /p-b, t-k, k-g/ ; or voiceless, heavily aspirated /p, t, k/. In this spectrographic study, VOT measures during Korean plosives produced by a patient with apraxia of speech were compared to those by age- and gender- matching normal subjects. The results indicated that there were partial overlaps between VOT of /b, d, g/ and those of /p, t, k/, implying that the errors were phonetic in nature. In addition, larger VOT variabilities in apraxia of speech compared to the normals were noted.

• Journal of the korean academy of Pediatric Dentistry
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• v.7 no.1
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• pp.47-51
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• 1980

The author have observed a case of supernumerary tooth occured between the maxillary right primary central Incisor and lateral incisor. Supernumerary permanent tooth is a common clinical finding, but supernumerary primary tooth is very rare. Supernumerary tooth result from aberrations in the initiation or proliferation period of the life cycle of the tooth.

• Journal of Korean Neurosurgical Society
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• v.61 no.3
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• pp.343-351
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• 2018

Diffuse intrinsic pontine glioma (DIPG) is a deadly paediatric brain cancer. Transient response to radiation, ineffective chemotherapeutic agents and aggressive biology result in rapid progression of symptoms and a dismal prognosis. Increased availability of tumour tissue has enabled the identification of histone gene aberrations, genetic driver mutations and methylation changes, which have resulted in molecular and phenotypic subgrouping. However, many of the underlying mechanisms of DIPG oncogenesis remain unexplained. It is hoped that more representative in vitro and preclinical models-using both xenografted material and genetically engineered mice-will enable the development of novel chemotherapeutic agents and strategies for targeted drug delivery. This review provides a clinical overview of DIPG, the barriers to progress in developing effective treatment, updates on drug development and preclinical models, and an introduction to new technologies aimed at enhancing drug delivery.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.19 no.5
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• pp.705-709
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• 2010

It is quite complex to draw the geometry of electron trajectories in electron optics because such trajectories have various aberrations that cannot be easily calculated. However, if we need to know roughly the geometry, the focal length and the principal planes in order to understand the properties of column, a simple numerical solution can be a useful method. We are developing the electron beam machining system based on SEM. In this paper, we show rough geometry, focal length and principal planes by a numerical solution for electron lens I in our column. These results will be utilized in developing a simulation program for electron optics.

• Environmental Analysis Health and Toxicology
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• v.15 no.4
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• pp.157-163
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• 2000

2- [(4- Cyanophenyl)amino] -3-chloro-1, 4- naphthalenedione (NQ-Y15) was asssayed for its genotoxic potential by using Salmonella typhimurium reversion assay and in vitro chromosome aberration test on Chinese hamster lung cells. In the Ames test, NQ-Y15 induced his + revertants of Salmonella typhimurium TA 98 and TA1537, reaching levels twice the negative control values. But, NQ-Y15 induced only his+ revertants of Salmonella typhimurium TA1537 more than twice the control values under the condition with metabolic activation system. In the cytogenetic test on chinese hamster lung cells. NQ -Y15 showed significant chromosomal aberrations, but the incidence was significantly reduced in the presence of metabolic activation.

• Korean Journal of Optics and Photonics
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• v.7 no.4
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• pp.305-313
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• 1996

Lens design method by using equivalent lenses was already introduced, but the method has a limitaion that all lenses should be in the air. Therefore, we often get improper solution in designing cemented lenses. In this study, the lens conversion from thick lens to equivalent lens and its reversal was generalized without any preconditions, and the third order aberration fomulrae were derived for the generalized equivalent lens system. The generalized equivalent lens conversion were applied to typical cemented doublet and triplet, and they show that the third order aberrations of the generalized equivalent lenses have better agreements with their corresponding thick lenses than the previous conversion method.

• Journal of the Optical Society of Korea
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• v.20 no.2
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• pp.234-238
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• 2016

A new method to design a low distortion, even relative illumination, optical see-through head-mounted display (HMD) with a freeform reflective mirror (FFRM) based on the two similar ellipsoids structure is proposed. The HMD we have realized has a simple structure which consists of two similar ellipsoid surfaces, an FFRM, a 7-piece co-axis relay lens, and an OLED. This structure can be applied to offset distortion, reach even relative illumination, and correct the off-axis aberrations. The HMD we finally have realized has a near 3% low distortion, a higher than 80% relative illumination, and a 40°×30° field of view (FOV).

• Journal of the Optical Society of Korea
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• v.15 no.3
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• pp.300-304
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• 2011

Optical microscopes are widely used for medical imaging these days, but biopsy is a lengthy process that causes many problems during the ex-vivo imaging procedure. The endo-microscope has been studied to increase accessibility to the human body and to get in-vivo images to use for medical diagnosis. This research proposes a multi-modal confocal endo-microscope for bio-medical imaging. We introduce the design process for a small endoscopic probe and a coupling mechanism for the probe to make the multi-modal confocal endo-microscope. The endoscopic probe was designed to decrease chromatic and spherical aberrations, which deteriorate the images obtained with the conventional GRIN lens. Fluorescence and reflectance images of various samples were obtained with the proposed endo-microscope. We evaluated the performance of the proposed endo-microscope by analyzing the acquired images, and demonstrate the possibilities of in-vivo medical imaging for early diagnosis.

• Journal of Plant Biology
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• v.8 no.1_2
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• pp.1-4
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• 1965

Beta-ray irradiation effects on structural changes of the chromosomes in root tip of rye, Secale cereale L., seedlings, particularly the frequency of chromosome bridge induction at anaphase stage treated with radioactive sulfur (S35) solutions were studied in this experiment. Among the four different concentrations of isotope solution, the lowest one, 0.4$\mu$c solution, has shown weak effect on the induction of chromosome aberration. On the other hand, higher concentration, 25.6$\mu$c solution, induced higher frequency of chromosome bridge induction as much as 4.3%. Concerning the relationship between the ages of after treatment and the ranges of concentration, the higher concentrations showed more pronounced effects than the lower ones.

• Korean Journal of Microbiology
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• v.17 no.3
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• pp.137-151
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• 1979

Germinating conidia of Aspergillus nidulans diploid heterozygous for color and other genetic markers were used to direct and distinguish genetic events such as mutation, mitotic crossingover and nondisjunction in a single test after treatment with N-methyl-N'-nitro-N-nitrosoguanidine (NG), mitomycin C(MC), and chloral hydrate(CH). The following results were obtained : 1. NG reduced the survival of conidia and increased the frequencies of miototic segregants about sevenfoli over the control ; among the mitotic segregants the predominant genetic event was mitotic crossingover. NG also produced many abnormal colonies, which appeared to be of the types caused by induced semidominant lethals or chromosomal aberrations, and the aneuploid types found spontaneously. 2. After treatment with MC the survival of conidia was reduced but few abnormal colonies were produced. The frequencies of miotic segregants were increased about threefold over the control ; in the mitotic segeregants the induced genetic event was mitotic crossingover. 3. CH gave no apparent effect on the survival of conidia and the frequencies of mitotic segregants. However, CH generated abnormal colonies, very greatly, which turned out to be of the aneuploid types. This result suggests that CH interferes with the normal distribution of chromosomes in mitosis.