• Maxillofacial Plastic and Reconstructive Surgery
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• v.15 no.3
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• pp.217-228
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• 1993

The purpose or this study was to observe the histological alteration of Langerhans cells on wound healing process in applying low energy laser irradiation. For this study, 50 Spraque-Dewly rats, weighing 150Gm or more were devided into control, experimental control group(0), 47.5Hz(1), 190Hz(3), 380Hz(5), 760Hz(7), lased group. All the experimental animals were made excision wound on buccal mucosa, 2mm depth, and lased with stoma laser (904nm, semconductor type ASGaAI, Sedalac France) 47.5Hz, 380Hz, 960Hz, 3minutes one time respectively except experimental control group. After the experiment, experimental animals were sacrificed after 24hours, 48hours, 72hours on each. Taken specimens were embedden in paraffin, sectioned 6-8u in thickness. And the langerhans cell were detected using ant S-100 protein antibody, and histochemically processed with Avidin Biotin complex method. All the Langerhan cells were calculated under light microspe in 400 multiplication field and standard deviation, probability test between each group were evaluated using statistical analysis system(S.A.S)program. Following results were obtained. 1. Langerhan cells were increased in experimental control group compared to that in control group(P<0.01). 2. 24hour after experiments, Langerhans cell were decreased compare to that in control group and control experimental group 5, 1, 3. Probability test shows significance between control experimental and 5, 1, 3 group on a =0.05 range. 3. 48our after experiment, Langerhans cells were decreased compare to that on experimental control group, and probability test shows significance between control experimental and 3, 7, 5 group an a=0.05 range. 4. 72hour after experiments, Langerhans cells were decreased compare to that on experimental control group and probability test on group comparison shows significance between control experimental and 1, 5 and 1 between 3, 7 between 3, and 5, between 7, respeilively on a=0.05 range. 5. Langerhans cells number in experimental group were decreased compare to that on experimental control group in applying laser irradiation.

• Transactions of the Society of Information Storage Systems
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• v.1 no.2
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• pp.127-131
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• 2005

We report a nanometer scale mark formation using a $PtO_x$ thin film or a TbFeCo rare-earth transition metal film and the mechanism. The multi-layer samples($ZnS-SiO_2/PtOx/ZNS-SiO_2,\;ZnS-SiO_2/TbFeCo/ZnS-SiO_2$) were prepared with a magnetron sputtering method on a polycarbonate or a glass substrate. By laser irradiation of approximately a few nanoseconds, nanometer scale marks were fabricated. During the fabrication process, the thin films were thermally reacted or inter-diffused during the laser irradiation. 75 nm bubble marks in the PtOx multi-layer sample by an approximately 4-ns laser irradiation. Inside the bubble mark, Pt particles with a few nanometer sizes are distributed. The $50{\sim}100$ nm bubble marks in the TbFeCo multi-layer sample by a few nanosecond laser irradiations. We will report the detail structure of the samples, the bubble mark formation process and the mechanism.

• Journal of the Optical Society of Korea
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• v.12 no.4
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• pp.309-313
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• 2008

We studied the sapphire and germanium fibers to determine which optical fiber best transmits Erbium:YAG laser for intracorporeal lithotripsy. Human calculi were ablated with an Erbium:YAG laser in contact mode using two fibers. Optical outputs at the distal end of fibers were measured before and after laser lithotripsy. Upon the irradiation on the calculus with the 50 mJ and 100 mJ pulse energy, the output energy at the distal end of germanium fiber declined to approximately 50% of the input energy. For the sapphire fiber, the output energy at the distal end remained unchanged with 100 mJ input energy; however the output energy had dropped to 50% for 200 mJ input energy. In order to examine how the types of target tissue affect the fiber damage, the sapphire fiber was tested for the irradiation on soft tissue and water as well. No energy decline was observed during soft tissue and water irradiation. We also characterized ablation craters with both optical fibers. Both fibers produced similar craters on calculi in terms of depth and diameter. Sapphire fibers are better suited than germanium fibers for Erbium:YAG lithotripsy in terms of the fiber damage.

• Journal of Sensor Science and Technology
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• v.22 no.5
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• pp.357-363
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• 2013

An ultraviolet pulsed laser ablation of polyimide film coated with platinum has been used to enhance the sensitivity for the application as an electrochemical biosensor. Densely packed cones are formed on polyimide surface after UV irradiation which results in increase of surface area. In order to apply the sensitivity improvement of laser ablated polyimide film electrodes, the glucose oxidase modified biosensor was fabricated by using an encapsulation in the gel matrix through sol-gel transition of tetraethoxysliane on the surface of laser ablated polyimide film. The optimum conditions for glucose determination have been characterized with respect to the applied potential and pH. The linear range and detection limit of glucose detection were from 2.0 mM to 18.0 mM and 0.18 mM, respectively. The sensitivity of glucose biosensors fabricated with laser ablated polyimide film is about three times higher than that of plain polyimide film due to increase in surface area by laser ablation.

• Transactions of Materials Processing
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• v.28 no.1
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• pp.27-33
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• 2019

The effect of hardening methods and process parameters on surface hardening of a Ti-6Al-4V Alloy has been investigated in this study. To characterize the effectiveness of the respective surface hardening methods, samples of a Ti-6Al-4V alloy were self-quenched, laser-nitrided, laser-carburized, laser-carbonitrided at the same laser irradiation conditions. This experimental procedure was followed by comparing the microstructural evolutions and mechanical properties of the respective samples after the laser surface hardenings. The hardening characteristics of the respective laser surface hardenings were well defined in this study, and the hardness was significantly influenced by the reaction compounds and laser energy density.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 1998.04a
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• pp.292-299
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• 1998

Case hardening behavior of tool steel(SK5) was investigated after YAG laser irradiation. In the case of beam passes, martensite formed in the melt zone and in former pearlite regions of the austenization zone exhibited very high Vickers Hardness values. The molten depth and radius, micro structure, hardness were investigated as a function of defocusing distance, pulse width, and power density.

• 한국정보디스플레이학회:학술대회논문집
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• 2006.08a
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• pp.838-841
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• 2006

Orientational alignment patterns proved that they are very useful for realizing diverse properties of liquid crystals. Here we tried to produce the patterns combining interfered laser light and double irradiations. A photo-isomerizable polymer doped with azo dye, which induce uniform liquid crystal alignment to the uniform laser irradiation, was used as the alignment layer. Double irradiations into two orthogonal directions brought the orientation patterns similar to the checkerboard. It indicates the possibility of bistability on those patterns.

• Proceedings of the Korean Society of Laser Processing Conference
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• 2001.05a
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• pp.22-26
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• 2001

• Proceedings of the Korean Society of Laser Processing Conference
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• 2002.11a
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• pp.109-113
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• 2002

• Medical Lasers
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• v.10 no.3
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• pp.132-137
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• 2021

The effects of low-level laser irradiation on cells and tissues, known as photobiomodulation therapy (PBMT), are the basis of photomedicine. Several investigations have evaluated the therapeutic effects of PBMT for neuronal regeneration and differentiation in animal models and humans. Recently, intranasal PBMT (iN-PBMT) has shown potential as a treatment method for neurologic disorders. In this review, we have summarized the various modes of iN-PBMT delivery and their application in the treatment of brain disorders.