• Medical Lasers
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• v.10 no.1
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• pp.1-6
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• 2021

Intravital microscopy is a high-resolution imaging technique based on laser-scanning two-photon and confocal microscopy, which allows dynamic 3D cellular-level imaging of various biological processes in a living animal in vivo. This unique capability allows biomedical researchers to directly verify a hypothesis in a natural in vivo microenvironment at the cellular level in a physiological setting. During the last decade, intravital microscopy has become an indispensable technique in several fields of biomedical sciences such as molecular and cell biology, immunology, neuroscience, developmental, and tumor biology. The most distinct advantage of intravital microscopy is its capability to provide a longitudinal view of disease progression at the cellular-level with repeated intravital imaging of a single animal over time by saving the images after each session.

• Tuberculosis and Respiratory Diseases
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• v.53 no.4
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• pp.431-438
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• 2002

Background : In order to investigate the usefulness and safety of Natural Stent, we performed this study in a canine model of tracheal stenosis induced using Nd-YAG laser. Materials and Methods : After tracheal stenosis was induced in 12 Mongrel dogs using Nd-YAG laser, either Dumon (n=6) or Natural (n=6) stent was inserted into the trachea. To assess the degree of stent migration and mucostasis, bronchoscopy was performed every week for 4 weeks, after which all stents were removed. One week after stent removal, tracheal stenosis was evaluated by bronchoscopy. Results : The degree of stent migration was not different between the dogs with Dumon stent ($3.0{\pm}0.8$) and those with Natural ($2.0{\pm}1.0$), nor was the degree of mucostasis, at Dumon ($1.7{\pm}0.5$) and Natural Stent ($1.5{\pm}0.6$), respectively. One week after stent removal, the degree of tracheal stenosis was not different between the Dumon ($1.5{\pm}0.5$) and the Natural group ($1.0{\pm}0.4$). In addition, there was no death and the degree of tracheal stenosis remained always within the safe limit (less than 2.0) in all animals. Conclusion : In a canine model of tracheal stenosis induced using Nd-YAG laser, the usefulness and safety of Natural Stent were similar to those of Dumon Stent. A clinical trial is necessary to document the usefulness and safety of Natural Stent in patients with tracheal stenosis.

• Journal of Life Science
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• v.18 no.9
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• pp.1257-1262
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• 2008

Photodynamic therapy (PDT) is a treatment utilizing the generation of singlet oxygen and other reactive oxygen species (ROS), which selectively accumulated in target cells. Genistein, soy-derived phytoestrogen, is one of the anticancer agents found in soybean. In the current study, we investigated the effect of photofrin-induced PDT and genistein on apoptotic cell death in head and neck cell line (AMC-HN3) to confirm the photodynamic therapy of genistein. It was determined by MTT assay that the combination group had more cytotoxicity effect than PDT group alone. Combination of photofrin PDT and genistein induced apoptosis more when comparing with PDT alone. Our data also showed that ROS was increased in combination therapy, indicating apoptosis by mitochondrial damage. These results indicated that the combination of photofrin PDT and genistein showed more cytotoxic effect and induced apoptosis in head and neck cancer cell line.

• Radiation Oncology Journal
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• v.14 no.4
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• pp.299-306
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• 1996

Purpose : Respiratory symptoms related with malignant airway disease have been the main causes of lowered qualify of life and also sometimes may be life-threatening if not properly managed. The authors report the short-term experiences of endobronchial brachytherapy for symptomatic malignant airway obstruction using high dose rate after-loading brachytherapy unit. Materials and Methdos : Twenty-five Patients with symptomatic malignant airway obstruction were treated with endobronchial brachytherapy between the period of December 1994 and March 1996 at Department of Radiation Oncology of Samsung Medical Center Twenty-one ($84\%$) were patients with non-small cell lung cancer, three with tracheal malignancies, and one with recurrence of esophageal cancer. Twenty Patients were given elective external beam radiation therapy, while six were given endobronchial laser evaporation therapy on emergency bases in addition to endobronchial brachytherapy. Three procedures for each patient were planned and total of 70 procedures were completed. Results : Improvement rates of major respiratory symptoms after endobronchial brachytherapy procedures were $88\%$(22/25). $96\%$(22/23), $100\%$ (15/15), and $100\%$(9/9) for cough, dyspnea, hemoptysis and obstructive pneumonia, respectively. ECOG performance scores were improved in $56\%$ of total patients group, while there was no case with worsened ECOG score. Fifteen patients died and the median interval from the start of treatment to death was 4 months (range: $1\~17$ months), while that of ten survivors was 9 months (range $5\~19$ months). There were five patients with controlled intrathoracic disease, who have survived over one rear. All deaths were associated with uncontrolled local and/or distant disease. Four Patients died of massive fatal hemoptysis, three of who received emergency endobronchial laser evaporation therapy before the start of endobronchial brachytherapy. Conclusion : Endobronchial brachytherapy has been confirmed as an excellent palliative treatment modality improving respiratory symptoms as well as patients' general performance status. Based on the current observations, use of endobronchial brachytherapy in curative setting as a boost technique may be warranted.

• Proceedings of the KOSOMBE Conference
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• v.1995 no.05
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• pp.173-178
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• 1995

This paper relates the occidental constitutional theory to the oriental one, concluding their origins to be similar, and demonstrates a new method of constitutional diagnosis by O-Ring Measurement System Of Muscular Meridians and Laser Constitutional Diagnosis. It establishes Laser Constitutional Diagnosis(L.C.D) using laser beams according to the principles of acupuncture and Sa-Sang constitutional physiology under the effect of spatial morphological energy of geometric isomers. Finally, hypothetical theory of L.C.D. was experimented by the O-Ring Measurement Systems of Muscular Meridians(O-R MSMM). O-R MSMM has been specially devised to improve the manual O-Ring Test prevailing to distinguish energetic response by muscle tonicity. Statistically, it has been proved that the constitutional diagnosis with O-R MSMM was highly effective and objective in the clinical experiences.

• Transactions on Electrical and Electronic Materials
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• v.12 no.6
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• pp.241-244
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• 2011

An isolator transmits light in the forward direction and blocks light from passing in the reverse direction. It is regarded an essential optical component in medical, industrial, and research lasers for blocking reflection beams that cause optical damage and noise. It is also used as a communicative light intensifier to expand the lifespan of devices and enhance transmission quality. This study analyzed the characteristics of the core components in the construction of a polarization-independent isolator, namely, the walk-off polarizer and the Faraday rotator. Measurement of the extinction ratio of the resultant walk-off polarizer revealed that the ratio between the vertical and horizontal rays was 1,050:1 with a laser output of 0.032 W and 1,010:1 with a laser output of 2.68 W, thus presenting ratios similar to 1,000:1. In addition, the walk-off polarizer and Faraday rotator constructed in this study were used to compare output changes according to changes in power of input light and to check the penetration ratio. Results from the study presented variations in output value according to changes in power of input light. However, the average penetration ratio remained relatively consistent (~81.4%).

• Journal of the Korean Society for Precision Engineering
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• v.28 no.12
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• pp.1347-1352
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• 2011

Recently, as the aged population grows around the world, many medical instruments, devices, and their fabrication processes are developing. Among the devices, a drug delivery stent is a good example for precision machining. Conventional drug delivery stent has problem of the remaining polymer because the drug is coated on the surface with it. If the drug is impregnated into the micro hole array on the stent surface, the polymer can be perfectly eliminated. Micro sized holes are generally fabricated by laser machining however, the fabricated holes do not have an enough aspect ratio to contain the drug or a good surface finish to deliver the stend to blood vessel tissue. To overcome these problems, we propose a vibration-assisted machining mechanism with PZT (Piezoelectric Transducers) for abrication of micro sized holes better. The results indicated that the burr size can be significantly decreased with vibration assisted in nanosecond pulse laser drilling test.

• Journal of Biomedical Engineering Research
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• v.17 no.4
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• pp.499-506
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• 1996

Blood flow velocimeter is an essential device to measure the blood flow in skin tissue. In this study, we developed a high-speed LDV(laser Doppler Velocimeter) that has real time processing capability using a DSP(digital signal processing) chip and is able to continuously measure information about blood-flow based on a noninvasive method using self-mixing type laser diode. This LDV system has a simpler structure than any other typical blood flow velocimeter and is composed of new self-mixing probe, stabilizer circuits DSP board, and interf'ace boule We measured velocity of speaker-unit by operational frequencies to identify Doppler effect of this system, performed clinical experiment on bare finger tip and compared it with a commercial euipment BPM403A(USA).

• Medical Lasers
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• v.9 no.1
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• pp.65-70
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• 2020

Bronchial foreign body aspiration (BFA) is a common but emergent condition in infants and children. Furthermore, it can result in various complications such as atelectasis, pneumonia, bronchiectasis, and pneumothorax. Among these, pneumothorax is a very rare complication. However, it can be fatal without the swift implementation of appropriate treatment. We experienced a case of 16-month-old girl with an aspirated peanut. The foreign body was fixed in her left main bronchus. A CO₂ laser was used to safely cut and break the foreign body. Removal was successful after breaking it. But after the process, inflammatory tissue of the tracheal mucosa was ruptured. Bilateral tension pneumothorax followed after the rupture. The patient was treated with bilateral chest tube insertion. Here we present this BFA case with a rare and unexpected complication. We also review the appropriate literature.

• Medical Lasers
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• v.8 no.2
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• pp.74-79
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• 2019

Periorbital melasma is often refractory to treatment and highly associated with rebound hyperpigmentation or mottled hypopigmentation after laser treatment in Asian patients. In this report, we describe 2 patients with cluster-1 periorbital melasma and 1 patient with cluster-2 periorbital melasma who experienced remarkable clinical improvements after microwave-generated, atmospheric-pressure, non-thermal nitrogen plasma treatments. All patients exhibited limited clinical responses after combination treatments with topical bleaching agents, systemic oral tranexamic acid, and low-fluenced Q-switched neodymium (Nd):yttrium-aluminum-garnet (YAG) lasers. Low-energy nitrogen plasma treatment at 0.75 J elicited remarkable clinical improvement in the periorbital melasma lesions without post-laser therapy rebound hyperpigmentation and mottled hypopigmentation. We deemed that a single pass of nitrogen plasma treatment at 0.75 J induces mild microscopic thermal tissue coagulation and modification within the epidermis while preserving the integrity of the basement membrane in patients with periorbital melasma. Accordingly, nitrogen plasma-induced dermal tissue regeneration could play a role in the treatment of melasma lesions.