• Medical Lasers
• /
• v.10 no.4
• /
• pp.207-213
• /
• 2021

Background and Objectives This study was undertaken to assess the stability and efficacy of laser therapy (808 nm), Liquiband (a commercial topical skin adhesive product), and a combination treatment, for application in oral ulcers. Materials and Methods The oral ulcer rat animal model was used to determine the efficacy of photobiomodulation, Liquiband, or combination therapy. Ulcers were induced by injecting 60% acetic acid in the oral mucosa. Three days after ulcer confirmation, the chemically induced ulcers were treated with either laser (808 nm), Liquiband, or a combination of both, every two days for 8 days (4 sessions). Combination therapy was performed by first treating with laser followed by application of the Liquiband. Reduction in ulcer area size was subsequently determined, and animals were sacrificed at 5 and 10 days after the last administration, for histological observation of the extracted oral ulcer tissue samples. Results In this study, treatment with either laser (808 nm) or commercial Liquiband product as well as the combined treatment significantly enhanced oral ulcer healing in the rat animal model. The effect of laser treatment is mainly attributed to collagen synthesis, whereas application of the Liquiband promotes vascularization and formation of granulation tissue. Our results indicate that further optimization of the combined therapy could synergistically and significantly enhance oral ulcer healing. Conclusion Laser or Liquiband treatment of oral ulcer in the rat animal model exert different outcomes, but both methods confirm significant effects relative to the untreated group. The combined treatment group with laser and Liquiband showed marked oral ulcer healing, but further optimization is required to get highly significant results and establish the potential synergistic effect of the combination therapy, as compared to the individual enhancing effects of healing oral ulcers.

• The Korean Journal of Pain
• /
• v.3 no.2
• /
• pp.139-143
• /
• 1990

There are several methods for the treatment of herpetic neuralgia, but there is no method that results in complete remission. The laser has lately come into use to reduce several acute or chronic pains. Twenty six patients who suffered from herpetic neuralgia were treated with Ne-Ne and Ga Al AS lasers simultaneously 2 or 3 times per week. In order to determine the degree of pain relief, we used the visual analogue scale. The results were as follows. 1) Low level laser therapy (LLLT) was a non-invasive, simple method. 2) The improvement rate after 15 irrradiations of laser was 63%. 3) The Highest improvement rate (24%) was shown after one irradiation of laser. 4) Only one patient above age 60 (3.8%) developed postherpetic neuralgia. 5) There was no significant difference effects of LLLT between above and below the age of 60. 6) There was no complication during or after irradiation of laser.

• 한국정보디스플레이학회:학술대회논문집
• /
• 2008.10a
• /
• pp.993-994
• /
• 2008

Electrochromic (EC) devices are capable of reversibly changing their optical properties upon charge injection and extraction induced by the external voltage. The characteristics of the EC device, such as low power consumption, high coloration efficiency, and memory effects under open circuit status, make them suitable for use in a variety of applications including smart windows and electronic papers. Coloration due to reduction or oxidation of redox chromophores can be used for EC devices (e-paper), but the switching time is slow (second level). Recently, with increasing demand for the low cost, lightweight flat panel display with paper-like readability (electronic paper), an EC display technology based on dye-modified $TiO_2$ nanoparticle electrode was developed. A well known organic dye molecule, viologen, was adsorbed on the surface of a mesoporous $TiO_2$ nanoparticle film to form the EC electrode. On the other hand, ZnO is a wide bandgap II-VI semiconductor which has been applied in many fields such as UV lasers, field effect transistors and transparent conductors. The bandgap of the bulk ZnO is about 3.37 eV, which is close to that of the $TiO_2$ (3.4 eV). As a traditional transparent conductor, ZnO has excellent electron transport properties, even in ZnO nanoparticle films. In the past few years, one-dimension (1D) nanostructures of ZnO have attracted extensive research interest. In particular, 1D ZnO nanowires renders much better electron transportation capability by providing a direct conduction path for electron transport and greatly reducing the number of grain boundaries. These unique advantages make ZnO nanowires a promising matrix electrode for EC dye molecule loading. ZnO nanowires grow vertically from the substrate and form a dense array (Fig. 1). The ZnO nanowires show regular hexagonal cross section and the average diameter of the ZnO nanowires is about 100 nm. The cross-section image of the ZnO nanowires array (Fig. 1) indicates that the length of the ZnO nanowires is about $6\;{\mu}m$. From one on/off cycle of the ZnO EC cell (Fig. 2). We can see that, the switching time of a ZnO nanowire electrode EC cell with an active area of $1\;{\times}\;1\;cm^2$ is 170 ms and 142 ms for coloration and bleaching, respectively. The coloration and bleaching time is faster compared to the $TiO_2$ mesoporous EC devices with both coloration and bleaching time of about 250 ms for a device with an active area of $2.5\;cm^2$. With further optimization, it is possible that the response time can reach ten(s) of millisecond, i.e. capable of displaying video. Fig. 3 shows a prototype with two different transmittance states. It can be seen that good contrast was obtained. The retention was at least a few hours for these prototypes. Being an oxide, ZnO is oxidation resistant, i.e. it is more durable for field emission cathode. ZnO nanotetropods were also applied to realize the first prototype triode field emission device, making use of scattered surface-conduction electrons for field emission (Fig. 4). The device has a high efficiency (field emitted electron to total electron ratio) of about 60%. With this high efficiency, we were able to fabricate some prototype displays (Fig. 5 showing some alphanumerical symbols). ZnO tetrapods have four legs, which guarantees that there is one leg always pointing upward, even using screen printing method to fabricate the cathode.

• Medical Lasers
• /
• v.9 no.2
• /
• pp.172-178
• /
• 2020

Background and Objectives This study aimed at examining the effects of photobiomodulation therapy (PBMT) on glucose, cholesterol, triglycerides, and low- and high-density lipoprotein (LDL and HDL, respectively) levels in vitro. Materials and Methods A total of 38 serum samples collected in plain (n=10) and heparinized tubes (n=28) were subjected to PBMT at 60 Joules (J)/cm² for 2 min at 810 nm. The glucose and lipid profiles, cholesterol, triglycerides, LDL, and HDL of each sample was measured before and after PBMT. Results A statistically significant increase in glucose levels was observed in the PBMT-sera in 8 out of 10 samples in plain tubes. However, only two samples that were prepared in heparinized tubes showed an increase in glucose levels. The remaining heparinized samples that were exposed to PBMT presented lower glucose values. The treated sera exhibited a fluctuation in the lipid profiles after PBMT. However, high cholesterol levels were evident following PBMT. Similar trends with HDL and LDL in heparinized tubes were evident. Conclusion Together, the findings suggest that photobiomodulation exhibits an effect on glycemic and lipid profiles in vitro. Hence, the use of low-level laser therapy could have therapeutic potential. However, the differences between individual responses appear to indicate that the impact of PBMT may not always be beneficial.

• Journal of Dental Rehabilitation and Applied Science
• /
• v.33 no.2
• /
• pp.119-126
• /
• 2017

Purpose: The aim of the present study was to compare clinical antiplaque and antigingivitis effect between Light Emitting Diode (LED) electronic toothbrush and electronic toothbrush without LED for gingivitis and mild periodontitis patients. Materials and Methods: 30 patients included in this study. 15 patients in experimental group used LED electronic tooth brush which has red and white LED within its head, and other 15 patients in control group used same product which specially modified that function without LED. Clinical parameters ($L{\ddot{o}}e-Silness$ gingival index (GI), Quigley-Hein plaque index (PI)) were measured at the baseline, 2 weeks and 4 weeks later. Wilcoxon signed rank test and Mann-Whitney test were used for statistical analysis. Results: Compare of GI change between experimental and control group with time, both groups showed that reduced GI, but lower GI values detected at 2 weeks and 4 weeks later in experimental group than control group. And lower PI values detected at 4 weeks later in experimental group than control group, but not statistically significant. Conclusion: Based on these results and within the limits of this study, the electronic toothbrush with LED could reducing gingivitis in a short period and infer that decreasing plaque accumulation in a long period.

• Korean Journal of Optics and Photonics
• /
• v.16 no.1
• /
• pp.13-20
• /
• 2005

Fiber-Bragg-grating external cavity laser(FGL) modules were fabricated and experimentally analyzed. Proposed as a cost-effective solution for optical sources in the WDM-PON access network, FGL modules were packaged to TO-CAN type. We obtained a low threshold current of 13 mA, and an optical output power of 3.6 mW with a bias current of 60 mA at $25^{\circ}C$. The lasing wavelength dependencies on current and temperature were as small as 5.2 pm/mA and 30 pm/$^{\circ}C$, respectively. These change rates of the wavelength with the temperature and current are smaller than those of the DFB laser. Single-mode oscillations with the side-mode suppression ratio(SMSR) over 30 dB are maintained above the threshold current level. The FGL modules can be directly modulated at 155 Mbps, PRBS(2$^{23}$ -1) NRZ signal. Through the BER plots, we did not see the significant degradations before and after the transmission over 20km of the SMF at 155 Mb/s.

• Korean Journal of Optics and Photonics
• /
• v.32 no.5
• /
• pp.235-243
• /
• 2021

Photobiomodulation (PBM)-based therapy, which uses a phenomenon in which a light source of a specific wavelength band promotes ATP production in mitochondria, has attracted much attention in the fields of biology and medicine because of its effects on wound healing, inflammation reduction, and pain relief. Research on PBM-based therapy has mainly used lasers and light-emitting diodes (LEDs) as light sources and, despite the advantages of organic light-emitting diodes (OLEDs), there have been only a few cases where OLEDs were used in PBM-based therapy. In this research, the skin-care effect of PBM was analyzed using red (λ = 620 nm), green (λ = 525 nm), and blue (λ = 455 nm) OLED lighting modules, and was compared to the PBM effect of LEDs. We demonstrated the PBM-based skin-care effect of the red, green, blue OLED lighting modules by measuring the increase in the amount of collagen type-1 synthesis, the inhibition of melanin synthesis, and the suppression of nitric oxide generation, respectively.