• Journal of the Korean Vacuum Society
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• v.18 no.1
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• pp.37-43
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• 2009

Temperature and injection current dependence of electroluminescence(EL) spectral intensity of the $In_xGa_{1-x}N$/GaN multi-quantum wells(MQW) have been studied over a wide temperature range and as a function of injection current level. It is found that a temperature-dependent variation pattern of the EL efficiency under very low and high injection currents shows a drastic difference. This unique EL efficiency variation pattern with temperature and current can be explained field effects due to the driving forward bias in presence of internal(piezo and spontaneous polarization) fields. Increase of the indium content in $In_xGa_{1-x}N$/GaN multiple quantum wells gives rise to a redshift of 80 meV and 22 meV for green and blue MQW, respectively. It can be explained by carrier localization by potential fluctuation of multiple quantum well and MQW structures also shows a keen difference owing to the different indium content in InGaN/GaN MQW.

• Journal of Life Science
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• v.20 no.7
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• pp.977-982
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• 2010

We investigated the anti-cancer effects of two dibenzocyclooctadiene lignans, gomisin A and gomisin N, isolated from Schizandra chinensis Baill, in human promyelocytic U937 cells. Gomisin N, but not gomisin A, inhibited cell growth in a concentration-dependent manner, which was associated with the induction of G1 arrest of the cell cycle. G1 arrest induced by gomisin N was correlated with down-regulation of cyclin E, cyclin-dependent kinase (Cdk) 2 and Cdk4, and a concomitant up-regulation of Cdk inhibitors such as p16 (INK4A) and p21 (WAF1/CIP1). Furthermore, gomisin N inhibited phosphorylation of retinoblastoma protein (pRB) and p130, and expression of transcription factor E2Fs. The results indicated that growth inhibition by gomisin N is related to cell cycle arrest at G1 in U937 cells and these findings suggest that gomisin N may be a useful chemotherapeutic agent.

• KSBB Journal
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• v.21 no.1 s.96
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• pp.34-41
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• 2006

The aim of this study is the development of biological removal process of methyl ethyl ketone (MEK) in odor gas, which is generated from the waste food recycling process. To develop the removal process of odor gas, MEK, the selection of proper biofilter support was carried out. When the biofilter equipment was passed by synthetic odor gas composed of 250 ppm of MEK, the maximum removal was achieved to $586.6g-MEK/m^3\;hr$ for polypropylene fibril as support. Under the same experimental conditions, the maximum removal in polyurethane support was obtained to $359.7 g-MEK/m^3\;hr$. Finally, the maximum removal in volcanic stone support was $56.2g-MEK/m^3\;hr$.

• Applied Microscopy
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• v.39 no.3
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• pp.219-226
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• 2009

The ultrastructure of spermatogenesis and sperm in Cichlasoma managuensis belonging to Cichlidae was investigated by light and electron microscopes. The testis of C. managuensis contained numerous testicular cysts, and spermatogenesis was synchronized in these testicular cysts. In the case of spermatogonia, the nucleus was comparatively large ellipsoidal, and mitochondria showed a marked development. The size of primary spermatocyte was smaller than that of spermatogonia, and that of secondary spermatocyte was smaller than that of primary spermatocyte. The chromatin of spermatocyte was highly condensed according to their development. The nucleus with electron-dense was round shape. In spermiogenesis, flagella started to be formed and chromatin was more condensed. The mitochondria were rearranged in a middle piece. The sperm was formed by loss of cytoplasm. The head of mature sperm was a spherical shape and had not acrosome. The microtubules of flagella were arranged 9+2 structure. Also, the tail of sperm have lateral fins.

• Journal of Veterinary Clinics
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• v.28 no.5
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• pp.533-537
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• 2011

A 13-year-old, female, Shih-tzu and a 10-year-old, female, Yorkshire terrier were presented with ulcerative keratitis caused by corneal endothelial degeneration. Generalized corneal edema, conjunctival hyperemia, focal corneal pigmentation, corneal neovascularization, sub-epithelial bullae, and positive fluorescein staining were observed during ophthalmic examinations. Thermokeratoplasty was performed on the overall edematous corneas. Healing of the cornea was completed within 25 days and corneal ulceration has not recurred after healing of the cornea in both cases. Other ocular complications were not observed except for a slight increase in corneal pigmentation. According to this study, thermokeratoplasty could be an effective treatment for corneal ulceration secondary to corneal endothelial diseases in dogs.

• Journal of The Korean Ophthalmological Society
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• v.59 no.12
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• pp.1181-1184
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• 2018

Purpose: To present a rare case of tear drainage since birth from a lacrimal ductule fistula, which is the first report in the Republic of Korea. Case summary: A 3-month-old female who presented with discharge of clear fluid from a small skin opening lateral to the right upper eyelid since birth visited the outpatient clinic. The patient was healthy and was receiving no medication. She was born on gestation age 35 weeks and 3 days. No other specific history or other ophthalmic abnormality was found. On examination, a small skin orifice approximately 2 mm diameter and no sign of infection or discoloration was observed. To relieve this symptom, the patient underwent a fistulectomy under general anesthesia. Histopathological examination of the surgical specimen was performed. The patient's symptom subsided postoperatively without recurrence. Conclusions: This is the first report in the Republic of Korea of tears draining from a lacrimal ductule fistula since birth and the subsequent clinical treatment procedures.

• Korean Journal of Ophthalmology
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• v.32 no.6
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• pp.506-516
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• 2018

Purpose: We measured the thicknesses of the ganglion cell and inner plexiform layer (GCIPL), the macula, and the retinal nerve fiber layer (RNFL) using spectral-domain optical coherence tomography in patients with idiopathic macula holes to analyze the repeatability of these measurements and compare them with those of the fellow eye. Methods: We evaluated 85 patients who visited our retinal clinic. The patients were divided into two groups according to their macular hole size: group A had a size of $<400{\mu}m$, while group B had a size of ${\geq}400{\mu}m$. Repeatability was determined by comparing the thicknesses of the GCIPL, macula, and RNFL with those of the normal fellow eye. Results: The average central macular thickness in patients with macular holes was significantly thicker than that in the normal fellow eye ($343.8{\pm}78.6$ vs. $252.6{\pm}62.3{\mu}m$, p < 0.001). The average thickness of the GCIPL in patients with macular holes was significantly thinner than that in the normal fellow eye ($56.1{\pm}23.4$ vs. $77.1{\pm}12.8{\mu}m$, p < 0.001). There was no significant difference in the average RNFL thickness between eyes with macular holes and fellow eyes ($92.4{\pm}10.0$ vs. $95.5{\pm}10.7{\mu}m$, p = 0.070). There were also no significant differences in the thicknesses of the GCIPL and RNFL among the two groups (p = 0.786 and p = 0.516). The intraclass correlation coefficients for the macula and RNFL were 0.994 and 0.974, respectively, in patients with macular holes, while that for the GCIPL was 0.700. Conclusions: Macular contour change with macular hole results in low repeatability and a tendency of thinner measurement regarding GCIPL thickness determined via spectral-domain optical coherence tomography. The impact of changes in the macular shape caused by macular holes should be taken into consideration when measuring the GCIPL thickness in patients with various eye diseases such as glaucoma and in those with neuro-ophthalmic disorders.

• Journal of the Korea Society of Computer and Information
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• v.26 no.9
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• pp.155-166
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• 2021

Recently, digital health care technology is spreading and developing in various fields. Therefore, in this paper, we realized that the field to which digital healthcare technology is not applied is the field of optometry, and implemented a digital healthcare optometry system for precise lens manufacturing. A device called Phoroptor is used to manufacture the lens, and this device sets the lens by measuring the visual acuity of the person who requested the glasses. And when the person to be measured wears glasses, a device called a PD meter is used to align the pupil center and lens focus. However, there is a limit to the convenience of precise lens production and optometry due to the absence of a database and program that can accumulate and analyze the PD measurement error, inconvenience and error due to manual control of the Phoroptor, and optometric information. Therefore, in this paper, PD meter design for more accurate PD measurement, Phoroptor design and Phoroptor control application design for automatic Phoroptor control, and a database and analysis program that automatically set lenses using optometry information for each subject had been designed. Based on this, ultimately, a digital healthcare optometry system using an optometry database has been implemented.

• Journal of Korean Neurosurgical Society
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• v.66 no.1
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• pp.72-81
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• 2023

Objective : Ischemia and hemorrhage of pituitary adenomas (PA) caused important clinical syndrome. However, the differences on clinical characteristics and surgical outcomes between these two kinds apoplexy were less reported. Methods : A retrospective analysis was made of patients with pituitary apoplexy between January 2013 and June 2018. Baseline and clinical characteristics before surgery were reviewed. All patients underwent transsphenoidal surgery and were followed up at least 1 year. Results : Total 67 cases (5.8%) among 1147 pituitary tumor patients were enrolled, which consisted of 28 (~2.4%) ischemic PA and 39 (~3.4%) hemorrhagic PA. There were more male patients in the ischemic group compared with hemorrhagic group (78.6% vs 53.8%, p=0.043). However, the mean age, tumor size and functional tumor ratio were significant higher in the hemorrhagic group. Headache was more common in ischemic PA (82.1%) than that of hemorrhagic PA (51.3%, p=0.011). Magnetic resonance imaging findings found that mucosal thickening and enhancement of the sphenoid sinus was observed in 15 ischemic PA patients (n=27, 55.6%), but none in patients with hemorrhagic PA (n=38, p<0.0001). It was worth noting that the rate of pre-surgical hypopituitarism in ischemic PA patients were seemed higher than that in hemorrhagic PA patients, but not significant. The two groups got a total tumor resection rate at 94.1% and 92.9%, independently. No significant difference on the operative time, blood loss in operation and complications in perioperative period was observed in two groups. After operation, cranial nerve symptoms recovered to normal at 81.8% of ischemic PA patients and 82.6% of hemorrhagic PA patients. Importantly, the incidence of postoperative hypopituitarism partially decreased in both groups, among which the rate of hypothyroidism in ischemic PA patients significantly decreased from 46.4% to 18.5% (p=0.044). Conclusion : Patients with ischemic PA presented different clinical characteristics to the hemorrhagic ones. Transsphenoidal surgery should be considered for the patients with neuro-ophthalmic deficits and might benefit for pituitary function recovery of the apoplectic adenoma patients, especially pituitary thyroid axis in ischemic PA patients.

• Journal of The Korean Ophthalmological Society
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• v.58 no.11
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• pp.1313-1316
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• 2017

Purpose: To report fundus photography using a smartphone in an infant with abusive head trauma. Case summary: An 8-month-old male infant presented to the emergency room with decreased consciousness and epileptic seizures that the parents attributed to a fall from a chair. He had no external wounds or fractures to the skull or elsewhere. However, computerized tomography of the brain revealed an acute subdural hematoma in the right cranial convexity and diffuse cerebral edema, leading to a midline shift to the left and effacement of the right lateral ventricle and basal cistern. The attending neurosurgeon promptly administered a decompressive craniectomy. Immediately after the emergency surgery, a fundus examination revealed numerous multi-layered retinal hemorrhages in the posterior pole extending to the periphery in each eye. He also had white retinal ridges with cherry hemorrhages in both eyes. We acquired retinal photographs using the native camera of a smartphone in video mode. The photographer held the smartphone with one hand, facing the patient's eye at 15-20 cm, and held a 20 diopter condensing lens at 5 cm from the eye in the other hand. Our documentation using a smartphone led to a diagnosis of abusive head trauma and to obtain the criminal's confession, because the findings were specific for repetitive acceleration-deceleration forces to an infant's eye with a strong vitreoretinal attachment. Conclusions: This ophthalmic finding had a key role in the diagnosis of abusive head trauma. This case presented the diagnostic use of a smartphone for fundus photography in this important medicolegal case.