• Journal of Biomedical Engineering Research
• /
• v.20 no.4
• /
• pp.495-502
• /
• 1999

We propose efficient speech signal processing algorithms and a system for cochlear implant in this paper. The outer and the middle car which perform amplifying, lowpass filtering and AGC, are modeled by an analog system, and the inner ear acting as a time-delayed multi filter and the transducer is implemented by the DSP circuit which enables real-time processing. Especially, the basilar membrane characteristic of the inner ear is modeled by a nonlinear filter bank, and then tonotopy and periodicity of the auditory system is satisfied by using a pitch-synchronous multi-spectra(PSMS) method. Moreover, most of the speech processing is performed by S/W so the system can be easily modified. And as our program is written in C-language, it can be easily transplanted to the system using other processors.

• Korean Journal of Ichthyology
• /
• v.27 no.3
• /
• pp.228-232
• /
• 2015

The structure of the ventricle in the heart of Hypomesus nipponensis was investigated by light and scanning electron microscope. The heart consisted of four consecutive chambers, the sinus venosus, atrium, ventricle and bulbus arteriosus. The wall of the ventricle was divided into endocardium, myocardium, subepicardium and epicardium. The valves were observed in the artrioventricular and bulboventricular junctions. The ventricular myocardium was an entirely spongy without coronary vessels. The trabecular network was formed with lumina included a central lumen and the trabecula was cylindrical shape. Collagen distribution was apparent in the subepicardium, artrioventricular valve and bulboventricular valve. But in the trabeculae, collagen distribution was observed partly in the base of the ventricle. Especially, the endocardial bridges were observed between trabeculae. These results might be considered that the structure of the ventricle in the heart of pond smelt is adapted to sedentary habit associated with its habitat and lifestyle.

• Proceedings of the Korean Institute of Surface Engineering Conference
• /
• 2018.06a
• /
• pp.82-82
• /
• 2018

광전소자용 투명전극으로 적용하기 위한 초박형 Al 박막에 대해서 기초연구를 수행하였다. 증착 전 챔버(chamber) 내 기저압력은 $3{\times}10^{-7}Torr$이하로 유지하였으며 Ar 불활성 기체의 유입을 통해 작업압력을 $1{\times}10^{-2}Torr$로 상승시켜 증착을 실시하였다. DC 마그네트론 스퍼터링법을 이용하여 유리기판상에 Al 박막의 증착을 실시하였으며, 박막의 두께가 3-12 nm인 Al 박막을 각각 형성하였다. 두께가 7 nm 일 때 면저항은 $135{\Omega}/{\square}$로 측정되었고 7 nm 이상인 두께의 박막은 두께가 증가할 때 면저항이 점진적으로 감소되는 경향을 확인할 수 있었다. 두께가 10 nm인 박막의 측정된 면저항은 $13.1{\Omega}/{\square}$로 두께 7 nm인 박막과 비교하였을 때 약 10배의 차이를 확인할 수 있었다. 두께 6 nm 이하인 박막은 면저항 측정이 불가능하였는데 이는 SEM 분석 결과, 연속박막을 이루지 못 하였기 때문이라고 결론을 내릴 수 있었으며, 두께 12 nm인 박막까지 완전한 연속박막이 형성되지 않았다. 각각의 박막에서 입자의 크기는 선 교차법(line intercept method)을 이용하여 시편당 평균 120개의 입자에 대한 평균값을 측정하였으며, 이론적으로 예상할 수 있는 바와 같이 두께가 증가할수록 입자크기도 비례하여 증가하게 되는 것을 확인할 수 있었다. 가시광선 파장영역 내 투과도의 경우, 3 nm 두께에서 평균 80% 이상의 투과도가 측정된 데 반하여, 4-5 nm 두께에서 평균 60%로 급격하게 감소되기 시작하며 그 이후, 두께 증가에 따라 투과도가 점진적으로 감소되는 경향을 확인할 수 있었다. 또한 Al 박막은 시간의 경과에 따른 표면의 산화가 진행되어 기존에 측정된 면저항보다 10-60%의 면저항이 증가하였는데 이는 두께가 얇을수록 더 산화의 영향을 많이 받기 때문에 나타난 결과로 보인다. 추후 산화방지막 및 빛반사방지막 층을 초박형 Al박막과 함께 Oxide/Metal/Oxide 구조로 형성하여 위와 같은 현상들을 해결하고 박막물성의 증진을 통해 투명전극에 적용을 목표로 한다.

• The Korean Journal of Zoology
• /
• v.31 no.2
• /
• pp.122-132
• /
• 1988

Ultrastructure of the cutaneous granular glands and production of their secretory granules in the water toad, Bufo steinegeri Schmidt, are studied with light and electron microscopes. Cutaneous granular glands of the water toad have gland cavity in dermis and gland duct in epidermis. Each gland cavity of the granular glands is consisted of 3 types of cells which are inner glandular epithelial cells, outermost myoepithelial cells and another kind of epithelial cells near the gland duct. Characteristically, cytoplasms of the glandular epitelial cells appeared multinucleated masses without differentiation into cells. Poisonous secretory graules excreated by the merocrine secretion are basicafly composed of 2 kinds of granules which are electron dense granules and electron lucent granules. These granules are fused each other and forming compounded structures. According to the granular size and differentiated levels, they are subdivided into 4 types of granules. Synthesis of these secretory granules is occurred at the smooth endoplasmic reticulums of the glandular epithelial cells and limiting membranes of these granules are also originated from these cell organelles.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
• /
• v.28 no.6
• /
• pp.434-439
• /
• 2002

Oral squamous cell carcinoma (OSCC) is one of the most common head and neck cancers. OSCC generally has a poor prognosis due to its tendency towards a local invasion and subsequent metastasis, which is mediated by multiple proteolytic enzymes and angiogenesis. Soy products contain high levels of isoflavonoids, including the tyrosine kinase inhibitor, genistein, which has been identified as a potent inhibitor of cell proliferation and in vitro angiogenesis. The purpose of this in vitro study is to evaluate the anti-cancer effect of genistein with respect to the angiogenesis and basement membrane invasion in OSCC. The highly invasive OSCC cell line, HSC-3 cells were cultured in the presence of $10{\mu}M$ genistein for 24h. To evaluate the effects of genistein on the invasiveness and the gelatinolytic activity, in vitro invasion assay and zymography were performed. In order to evaluate the effect on the VEGF and bFGF mRNA expression, RT-PCR and northern hybridization reaction, and chemiluminescence detection were applied. The in vitro invasion assay showed that the genistein treatment reduced the cellular invasion through the artificial basement membrane and significant difference between the control group and the genistein treated group was shown in MMP-2 activity. Especially, the 62 kDa activated form of MMP-2 in the control group was 1.8 times higher than that in the genistein treated group. The results of the northern blot analyses indicated that VEGF mRNA expression in the genistein treated group was significantly down regulated. This study showed that genistein inhibits angiogenesis and reduces basement membrane invasion in OSCC. It seems to support the possibility of genistein as an anti-cancer agent.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.33 no.2A
• /
• pp.98-106
• /
• 2008

To reduce the outage probability and to increase the transmission capacity, the importance of repeaters in cellular systems keeps increasing. Unlike optical repeaters which require wireline connections, RF repeaters are easy to install, have low limitations in location and also have a reduced operational expense such as the optical fiber maintenance cost. On the other hand, RF repeaters suffer the interference due to the feedback signals between the transmitter and receiver antennas, hence require an extra interference cancellation method when the amount of the feedback signal reduction by using the shielding is not sufficient. In this paper, a channel estimation method for two-path feedback interference signals in the ICS (Interference Cancellation System) repeaters using baseband signal processing is proposed and its performance is evaluated. When compared with the conventional method which estimates each multipath individually, the proposed method achieves 10 dB performance gain in terms of the normalized mean-squared-error.

• Journal of Veterinary Clinics
• /
• v.30 no.2
• /
• pp.107-110
• /
• 2013

A 6-year-old, castrated male Shih-tzu dog was presented due to left side facial paralysis with head tilt. Neurological examination revealed absence of facial sensation, menance response, and palpebral reflex on the left side. On magnetic resonance imaging (MRI), intracranial intra-arachnoid cyst (IIAC) was noted. The dog was poor response to steroid and dieuretic therapy. Based on characteristic historical and clinical findings, and excluding of other causes of acute facial nerve dysfunction, the dog was tentatively diagnosed as idiopathic facial paralysis. The clinical signs were improved gradually after acupuncture therapy with bee venom. Eight weeks after initial acupuncture with bee venom, the patient recovered sensory and neurological facial signs. This case report demonstrates that bee venom acupuncture for an idiopathic facial paralysis could be useful in a dog.

• Pediatric Infection and Vaccine
• /
• v.30 no.1
• /
• pp.1-11
• /
• 2023

Respiratory syncytial virus (RSV) is a pathogen with a high burden of disease and social cost among infants worldwide, but the development of a vaccine has been delayed. The recent understanding of the pathogenesis of RSV, progress in reverse genetics, and successful implementation of other maternal immunizations have prompted the recent rapid development of monoclonal antibodies (mAbs) and vaccines for RSV prevention. Phase 3 clinical trials for two next-generation mAbs (nirsevimab and clesrovimab) and two maternal RSV pre-F vaccines are currently underway or have been recently completed. Soon, we might be able to protect young infants through long-acting mAbs and/or maternal immunization. Additionally, the development of live-attenuated vaccine candidates that are capable of avoiding enhanced RSV disease is ongoing. We need to gain familiarity with these newly developed strategies and collect epidemiological data on domestic RSV to adequately prepare for a new era of RSV prevention.

• Childhood Kidney Diseases
• /
• v.8 no.2
• /
• pp.205-213
• /
• 2004

Purpose: To evaluate the clinical manifestations of various glomerular diseases in children, a clinicopathological study was performed in 52 children who had renal biopsy. The type and relative incidence of the glomerular pathologies were analyzed, and the clinical predictability and usefulness of renal biopsy in glomerular diseases were assessed. Methods: Medical records of fifty two children with renal disease who had undergone percutaneous renal biopsy under ultrasonic guidance at Chungnam University Hospital from October 1995 to August 2003 were reviewed. In addition, we compared the clinical findings before renal biopsy with the pathological diagnosis. Results: The male to female ratio was 1.6:1 and they were $9.8\pm2.6$ years old on average. The chief complaints for biopsy were hematuria in 22 cases which was the most common (42.3%), proteinuria in 16 cases(30.8%), and hematuria & proteinuria(26.9%). Among the 22 cases of hematuria, there were 15 cases of gross hematuria(68.2%) and 7 cases of microscopic hematuria(31.8%). In terms of histopathologic diagnosis, most of them were primary glomerular diseases(84.6%), which included IgA nephropathy(28.8%), thin glomerular basement membrane disease(25.0%), focal segmental glomerulosclerosis(FSGS)(11.5%), membranous proliferative glomerulonephritis(7.7%), minimal change lesion(3.8%), acute poststreptococcal glomerulonephritis(3.8%) and membranous glomerulonephritis(3.8%). The clinical manifestations and pathologic diagnosis were not correlated. Conclusion: The clinical manifestations could not predict the pathological diagnosis. Therefore, renal biopsy would be inevitable in diagnosis of glomerular diseases for effective management and assessment of prognosis.

• Tuberculosis and Respiratory Diseases
• /
• v.57 no.6
• /
• pp.543-552
• /
• 2004

Background : Airway remodeling of the asthmatic airway, the result of persistent inflammation in the bronchial wall, is associated with irreversible airway obstruction and the severity of asthma. Previous reports had represented that adminitering CpG-oligodeoxynucleotides (CpG-ODN) before sensitization or challenge by allergens inhibits the development of eosinophilic airway inflammation in a murine model of asthma, but the effects of CpG-ODNs on chronic inflammation and airway remodeling had not been characterized. To investigate the influence of CpG-ODNs on chronic inflammation and remodeling of the airway, we performed studies using a murine model of chronic allergen-induced asthma. Methods : Balb/C mice were sensitized to ovalbumin(OVA) and subsequently exposed to nebulized OVA by means of inhalation twice weekly for 7 weeks. CpG-ODNs($30{\mu}g$) was administered intraperitoneally at sensitization. After final inhalation, mice were evaluated for airway hyperresponsiveness, chronic airway inflammation and remodeling. Results : The mice exposed to chronic and recurrent airway challenge with OVA had persistent airway hyperresponsiveness, chronic inflammation and airway remodeling. Mice treated with CpG-ODNs exhibited decreased bronchial hyperresponsiveness, OVA-specific IgE, chronic inflammation and evidence of airway remodeling, including goblet cell hyperplasia and subepithelial fibrosis. Conclusion : CpG-ODNs was thought to prevent chronic inflammation and remodeling changes in a murine model of chronic asthma.