• Journal of Biomedical Engineering Research
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• v.23 no.3
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• pp.243-251
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• 2002

Synthetic zinc wave employs Pulsed plane wave as transmit beam with linear time delay curve. The received echoes in different transmit directions at different transmit times are superposed at imaging Points with Proper time delay compensation using synthetic focusing scheme. This scheme. which uses full aperture in transmit, obtains a high SNR image, and also features high lateral resolution by using two way dynamic focusing at all imaging depths. In this Paper, we consider the Problems in realization of synthetic zinc wave. Also. we have applied the scheme to obtain phantom and in-vivo images using a linear array of 5 MHz. In phantom test. experimental images show high resolution over a more extended imaging depth than conventional fixed Point transmit and receive dynamic focusing schemes In-vivo images show that the resolution could not overcome conventional focusing systems because of motion blurring and(or) aberration of tissue. but the frame rate tan be increased by a factor of more than 5 compared to conventional focusing schemes. with competitive resolution at all imaging depths .

• Bulletin of the Korean Chemical Society
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• v.27 no.5
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• pp.637-641
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• 2006

Although chiral separation has been one of the main topics of chromatographic practice for over twenty-five years, it still presents many difficulties. In this work, the ultrasonic dependence of chiral resolution was investigated at various temperatures to improve resolution and reduce analysis time. The chiral resolution was performed on recently commercialized two HPLC chiral stationary phases (CSP 1 and CSP 2) with the analogues of racemic N-acylnaphthylethylamines (1a-d) and racemic amino acid derivatives (2a-c, 3a-c) as analytes. The CSP 1 was prepared from a (R)-N-(3,5-dinitrobenzoyl)phenylglycinol and the CSP 2 was prepared from a (S)-N-3,5-(dinitrobenzoyl) leucine. From the comparison of the chromatographic results under sonic condition with those under non-sonic condition, we found that the ultrasound decreased the elution time in chiral chromatography at all temperatures and improved the enantioselectivity at high temperature (45, 50, 60 ${^{\circ}C}$).

• The Journal of the Acoustical Society of Korea
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• v.33 no.5
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• pp.300-308
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• 2014

Photoacoustic imaging is a useful tool for the diagnosis of atherosclerosis because it is capable of providing anatomical and pathological information at the same time. A photoacoustic signal detector is a pivotal element to achieve high spatial resolution, so that it should have broadband spectrum with a high center frequency. Since a photoacoustic imaging probe is directly inserted into blood vessel to diagnose atherosclerosis, the total size of the photoacoustic signal detector should be less than 1 mm. The main purpose of this paper is to demonstrate that PVDF can be used as an active material for the photoacoustic signal detector with a high frequency and broadband characteristic. The photoacoustic signal detector developed in this study was a single element ultrasound transducer with an aperture of $0.5{\times}0.5mm$ and the total size of 1 mm. In the design stage, the natural focal depth was adjusted for an effective focal area to cover the region of interest, i.e., 1~5 mm in depth. This was because geometrical focusing could not be used due to the small aperture. Through a pulse-echo test, it was ascertained that the developed photoacoustic signal detector has the -6 dB bandwidth ranging between 40.1 and 112.8 MHz and the center frequency of 76.83 MHz.

• Journal of Veterinary Clinics
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• v.40 no.2
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• pp.152-157
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• 2023

A two-year-old, spayed female, Bichon Frise, was referred for severe corneal edema and corneal ulcer in the left eye (OS). The cornea had gradually swelled over one week after phacoemulsification performed a month prior, and that was refractory to 5% sodium chloride eye drop instillation or temporary partial tarsorrhaphy. A complete ophthalmic examination was performed. Severe corneal edema with intrastromal bullae and moderate anterior chamber flare was found on slit-lamp biomicroscopy in the OS, which obstructed the fundus examination. Corneal thickness was measured using high-resolution ultrasound biomicroscopy. The thickness of the OS cornea was 2.74 mm. The "letter-box" conjunctival flap was planned. Dorsal and ventral superficial keratectomy followed by a hood conjunctival flap was performed. Topical and systemic antibiotics and 5% sodium chloride eye drops were prescribed. Decreased corneal thickness was observed at one week, two weeks, and two months postoperatively (1.53 mm, 1.32 mm, and 0.92 mm, respectively). There were no postoperative complications, such as ocular discomfort or recurrent corneal ulcers. The "letter-box" conjunctival flap, a type of superficial keratectomy and conjunctival advancement hood flap, effectively relieved the severe irreversible corneal edema. This could be a simple but effective surgical intervention for patients with endothelial cell damage especially after phacoemulsification.

• The Journal of Korean Orthopaedic Ultrasound Society
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• v.4 no.2
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• pp.101-110
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• 2011

To describe the background, mechanism, clinical results and complications of prolotheapy based on the literature review. Prolotherapy is a minimally invasive injection-based treatment of chronic musculoskeletal pain, including ligament and joint laxity. The mechanism of this injection-based technique is to initiate a local inflammatory response with resultant tissue healing. The used proliferants are classified by bio-mechanism to act in three different ways as osmotic, irritants, and chemotatics. The most commonly used proliferant is hyperosmolar (10~25%) dextrose to act by osmotic rupture of cells. High resolution ultrasound imaging of musculoskeletal structure provide a more accurate diagnosis. Also ultrasound-guided intervention provides a more high efficacy and low rate of complications. The most common complication is local pain at the injected site, that is self-limited and good responsive to anti-inflammatory agents. Other complications are rare. It is reported that prolotherapy appears safe when performed by an experienced clinician. Prolotherapy has grown in popularity and has received significant recent attention. However there are limited evidence-based data supporting the indication and efficacy of prolotherapy in the treatment of chronic musculoskeletal pain or soft tissue injuries. Future studies are necessary to determine whether prolotherapy can play an independent and definitive role in a treatment for chronic musculoskeletal pain.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.35S no.6
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• pp.66-71
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• 1998

High spatial resolution ultrasonic imaging is necessary in several fields of investigation, in order to permit greater precision of clinical diagnosis in the dermatology, ophthalmology etc. We present a B-mode scan system using sector scanning probe of 20MHz center frequency. This developed system allow the high resolution image of 250${\mu}m$ in lateral and 80${\mu}m$ in axial, which of display the size of a $5mm {\times} 5mm$ image with 20 frames/sec. We have shown the images of various structural elements of the human skin and of the nail. We have compared the skin images obtained for each of the different age and we have shown in a general with the age, the atrophy of the skin thickness and the appearance of the abnormal hypoechogene band under epidermis (named SENEB : Sub Epidermal Non Echogene Band).

• International Journal of Vascular Biomedical Engineering
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• v.4 no.2
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• pp.25-30
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• 2006

We intended to measure the IT, MT, and the IMT of carotid artery separately and tried to analyze the clinical significance. Two hundred and fifty consecutive patients (125 males, 125 females) underwent carotid artery scanning using high-resolution ultrasound. The images were off-line analyzed using B-mode ultrasound image processing, devised in our research. We measured the IT, MT, and IMT semi-automatically at the far wall of designated 1cm length of the right common carotid and calculated the average values over the 200 points. The IT (p < 0.05), MT (p < 0.05) as well as IMT (p < 0.01) of patients with atherosclerotic disease were significantly thicker than that of the patients without atherosclerotic disease. Patients with hypertension showed significantly thicker IT (p < 0.05), MT (p < 0.01), and IMT (p < 0.01) than that of the patients without hypertension. However, only IT was thicker in patients with smoking (p < 0.05) than that of the patients without smoking. Smoking was associated only with intima while hypertension was associated with the all three layer's thickness. This result suggests the atherosclerotic process can be different by cardiovascular risk factors.

• Korean Journal of Medicinal Crop Science
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• v.22 no.2
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• pp.147-153
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• 2014

The Ponciri fructus immaturus (Poncirus trifoliata Rafinesque) has been used in oriental medicine for uterine contraction, stomachache, abdominal distension and cardiovascular diseases. Two main compounds, poncirin and naringin were successfully analyzed by high performance liquid chromatography (HPLC) and carried out method validation according to ICH guideline. A successful resolution and retention times were obtained with a $C_{18}$ reversed phase column, at an $1m{\ell}min^{-1}$ flow rate, with a gradient elution of a mixture of methanol, water and acetonitrile. Poncirin and naringin showed good linearity ($R^2$ > 0.999) in relatively wide concentration ranged. The recovery of each compound was 95.81 ~ 101.48% with R.S.D. values less than 1.0%. The application of ultrasound-assisted extraction was shown to be more efficient in extracting poncirin and naringin from Ponciri fructus immaturus. The predicted optimal poncirin and naringin yield were poncirin 2.15%, naringin 1.65% under an extraction temperature of $40^{\circ}C$, an extraction time of 10 min in a solvent of 70% methanol.

• Journal of Biomedical Engineering Research
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• v.32 no.2
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• pp.158-164
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• 2011

Breast cancer is the most frequently appearing cancer in women, these days. To reduce mortality of breast cancer, periodic check-up is strongly recommended. X-ray mammography is one of powerful diagnostic imaging systems to detect 50~100 um micro-calcification which is the early sign of breast cancer. Although x-ray mammography has very high spatial resolution, it is not easy yet to distinguish cancerous tissue from normal tissues in mammograms and new tissue characterizing methods are required. Recently ultrasound elastography technique has been developed, which uses the phenomenon that cancerous tissue is harder than normal tissues. However its spatial resolution is not enough to detect breast cancer. In order to develop a new elastography system with high resolution we are developing x-ray elasticity imaging technique. It uses the small differences of tissue positions with and without external breast compression and requires an algorithm to detect tissue displacement. In this paper, computer simulation is done for preliminary study of x-ray elasticity imaging. First, 3D x-ray breast phantom for modeling woman's breast is created and its elastic model for FEM (finite element method) is generated. After then, FEM experiment is performed under the compression of the breast phantom. Using the obtained displacement data, 3D x-ray phantom is deformed and the final mammogram under the compression is generated. The simulation result shows the feasibility of x-ray elasticity imaging. We think that this preliminary study is helpful for developing and verifying a new algorithm of x-ray elasticity imaging.

• Journal of the Korean Institute of Telematics and Electronics
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• v.21 no.4
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• pp.65-71
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• 1984

The design formular of optical focusing systems cannot be applied to ultrasonic B scanners, which use broadband pulses instead of continuous wave. In this paper, a calculation method is studied for analyzing the propagation of ultrasonic broadband pulse excited by ultrasonic array transducers. Using the results, seveial design parameters such as the number of transducer elements, delay time, and the focal point are determined to obtain high resolution in the ultrasonic dynamic focusing system. A dynamic focusing system with low-noise switching characteristics; which attains lateral resolution of 2-3mm all along the axial direction up to 18 cm with a 3.5 MHz linear array transducer, was implemented.