• Advances in nano research
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• v.7 no.4
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• pp.233-240
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• 2019

The present research work reports in-vitro anti-cancer activity of biologically synthesized ZnO nanoparticles (ZnO NPs) against human carcinoma cells viz SCC-40, SK-MEL-2 and SCC-29B using Sulforhodamine-B (SRB) Assay. ZnO NPs were synthesized by a unique and novel biological route using Temperature-gradient phenomenon where the extract of combination of Catharanthus roseus (L.) G. Don (C. roseus), Azadirachta indica (A. indica), Ficus religiosa (F. religiosa) and NaOH solution were used as synthesis medium. The morphology of the ZnO NPs was characterized by Transmission Electron Microscopy (TEM). TEM images reveal that particle size of the samples reduces from 76 nm to 53 nm with the increase in reaction temperature and 68 nm to 38 nm with the increase in molar concentration of NaOH respectively. XRD study confirms the presence of elements and reduction in crystallite size with increase in reaction temperature and NaOH concentration. The diffraction peaks show broadening and a slight shift towards lower Bragg angle ($2{\theta}$) which represents the reduction in crystallite size as well as presence of uniform strain. The FTIR spectra of the extract show transmittance peak fingerprint of Zn-O bond and presence of bioactive molecules These NPs exhibit inhibition greater than 50% for SCC-40, SK-MEL-2 and SCC-29B cell lines and more than 50% cell kill for SCC-29B cells at concentrations < $80{\mu}g/ml$. Nanoparticles with smallest size have shown better anti-cancer activity and peculiar cell-selectivity. The combination of extracts of these plants with ZnO NPs can be used in targeted drug delivery as an effective anti-cancer agent, a potential application in cancer treatment.

• Journal of Advanced Navigation Technology
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• v.23 no.4
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• pp.273-280
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• 2019

There are many studies that use structure health monitoring to reduce maintenance costs for aircraft and to increase aircraft utilization. Many studies on FBG sensors are also being conducted. However, if the FBG sensor is installed inside the composite, voids will occur between the layers of the composite, resulting in signal split problem. In addition, the FBG sensor is not affected by electromagnetic waves, but will produce electromagnetic noise caused by electronic equipment during post-processing. In this paper, to reduce the error caused by these noises, the stationary wavelet transform, which has the characteristics of movement immutability and is efficient in nonlinear signal analysis, is presented. And in the above situation, we found that noise rejection performance of stationary wavelet transform was better compared with the wavelet packet transform.

• Journal of Advanced Navigation Technology
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• v.24 no.6
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• pp.465-470
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• 2020

Complex materials are widely used in aviation industries where lightweighting is essential because they have lighter properties than metals. However, composite materials can cause defects such as internal void formation, poor adhesive mixing, and non-adhesive parts during the production process, and there is a risk of micro-cracking and interlayer separation due to low energy impact. Therefore, a structural damage test is essential. As a result, structural integrity monitoring using FBG is drawing attention. Compared to conventional electrical sensors, FBG has the advantage of being more corrosion-resistant and multiplexed without being affected by electrical noise. However, interloggers measuring FBG are expensive and have a large disadvantage because they are made on the premise of measuring large structures. In this paper, low-cost interloggers were designed for use in unmanned or small aircraft using optical switche, WDM filter, and LTFs, and compared to conventional high-priced interrogator.

• Progress in Medical Physics
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• v.33 no.4
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• pp.108-113
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• 2022

Purpose: Proton therapy has been used for optimal cancer treatment by adapting its Bragg-peak characteristics. Recently, a tissue-sparing effect was introduced in ultrahigh-dose-rate (FLASH) radiation; the high-energy transmission proton beam is considered in proton FLASH therapy. In measuring high-energy/ultrahigh-dose-rate proton beam, Faraday Cup is considered as a dose-rate-independent measurement device, which has been widely studied. In this paper, the feasibility of the simply designed Faraday Cup (Poor Man's Faraday Cup, PMFC) for transmission proton FLASH therapy is investigated. Methods: In general, Faraday cups were used in the measurement of charged particles. The simply designed Faraday Cup and Advanced Markus ion chamber were used for high-energy proton beam measurement in this study. Results: The PMFC shows an acceptable performance, including accuracy in general dosimetric tests. The PMFC has a linear response to the dose and dose rate. The proton fluence was decreased with the increase of depth until the depth was near the proton beam range. Regarding secondary particles backscatter from PMFC, the effect was negligible. Conclusions: In this study, we performed an experiment to investigate the feasibility of PMFC for measuring high-energy proton beams. The PMFC can be used as a beam stopper and secondary monitoring system for transmission proton beam FLASH therapy.

• Progress in Medical Physics
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• v.33 no.4
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• pp.80-87
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• 2022

Purpose: Proton therapy has different relative biological effectiveness (RBE) compared with X-ray treatment, which is the standard in radiation therapy, and the fixed RBE value of 1.1 is widely used. However, RBE depends on a charged particle's linear energy transfer (LET); therefore, measuring LET is important. We have developed a LET measurement method using the inefficiency characteristic of an EBT3 film on a proton beam's Bragg peak (BP) region. Methods: A Gafchromic EBT3 film was used to measure the proton beam LET. It measured the dose at a 10-cm pristine BP proton beam in water to determine the quenching factor of the EBT3 film as a reference beam condition. Monte Carlo (MC) calculations of dose-averaged LET (LET_d) were used to determine the quenching factor and validation. The dose-averaged LETs at the 12-, 16-, and 20-cm pristine BP proton beam in water were calculated with the quenching factor. Results: Using the passive scattering proton beam nozzle of the National Cancer Center in Korea, the LET_d was measured for each beam range. The quenching factor was determined to be 26.15 with 0.3% uncertainty under the reference beam condition. The dose-averaged LETs were measured for each test beam condition. Conclusions: We developed a method for measuring the proton beam LET using an EBT3 film. This study showed that the magnitude of the quenching effect can be estimated using only one beam range, and the quenching factor determined under the reference condition can be applied to any therapeutic proton beam range.

• Progress in Medical Physics
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• v.33 no.4
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• pp.114-120
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• 2022

Purpose: Particle beam therapy is advantageous over photon therapy. However, adequately delivering therapeutic doses to tumors near critical organs is difficult. Nanoparticle-aided radiation therapy can be used to alleviate this problem, wherein nanoparticles can passively accumulate at higher concentrations in the tumor tissue compared to the surrounding normal tissue. In this study, we investigate the dose enhancement effect due to gold nanoparticle (GNP) when Carbon-12, He-4, and proton beams are irradiated on GNP. Methods: First, monoenergetic Carbon-12 and He-4 ion beams of energy of 283.33 MeV/u and 150 MeV/u, respectively, and a proton beam of energy of 150 MeV were irradiated on a water phantom of dimensions 30 cm×30 cm×30 cm. Subsequently, the secondary-particle information generated near the Bragg peak was recorded in a phase-space (phsp) file. Second, the obtained phsp file was scaled down to a nanometer scale to irradiate GNP of diameter 50 nm located at the center of a 4 ㎛×4 ㎛×4 ㎛ water phantom. The dose enhancement ratio (DER) was calculated in intervals of 1 nm from the GNP surface. Results: The DER of GNP computed at 1 nm from the GNP surface was 4.70, 4.86, and 4.89 for Carbon-12, He-4, and proton beams, respectively; the DER decreased rapidly with increasing distance from the GNP surface. Conclusions: The results indicated that GNP can be used as radiosensitizers in particle beam therapy. Furthermore, the dose enhancement effect of the GNP absorbed by tumor cells can aid in delivering higher therapeutic doses.

• Journal of the Semiconductor & Display Technology
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• v.22 no.4
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• pp.103-107
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• 2023

To solve the reliability problem of organic devices that are often used outdoors, multifunctional gas barriers that block reactive gases such as moisture and oxygen and reflect harmful light such as ultraviolet rays are needed. In this study, ALD nanolaminate-based optically functional n-DBR was developed to overcome the poor gas permeability of polymer substrates and protect organic devices from harmful light. n-DBR not only achieved a WVTR of 8.76 × 10^-6 g·m^-2·day^-1, but also showed a visible light transmittance of 94.3% and an ultraviolet ray blocking ability of 2.67%. In particular, n-DBR based on a nanolaminate structure maintained its permeability characteristics even in a high temperature and high humidity environment despite being used as a layer of Al₂O₃. This functional barrier Structure can not only be used as a functional encapsulation barrier for the reliability of organic devices, but can also be used as a tinting film for vehicles.

• The Journal of Korean Society for Radiation Therapy
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• v.25 no.2
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• pp.107-113
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• 2013

Purpose: To verify accuracy of respiratory gated proton therapy by measuring and analyzing proton beam delivered when respiratory gated proton therapy is being performed in our institute. Materials and Methods: The plan data of 3 patients who took respiratory gated proton therapy were used to deliver proton beam from proton therapy system. The manufactured moving phantom was used to apply respiratory gating system to reproduce proton beam which was partially irradiated. The key characteristics of proton beam, range, spreat-out Bragg peak (SOBP) and output factor were measured 5 times and the same categories were measured in the continuous proton beam which was not performed with respiratory gating system. Multi-layer ionization chamber was used to measure range and SOBP, and Scanditronix Wellhofer and farmer chamber was used to measure output factor. Results: The average ranges of 3 patients (A, B, C), who had taken respiratory gated proton therapy or not, were (A) 7.226, 7.230, (B) 12.216, 12.220 and (C) 19.918, 19.920 $g/cm^2$ and average SOBP were (A) 4.950, 4.940, (B) 6.496, 6.512 and (C) 8.486, 8.490 $g/cm^2$. And average output factor were (A) 0.985, 0.984 (B) 1.026, 1.027 and (C) 1.138, 1.136 cGy/MU. The differences of average range were -0.004, -0.004, -0.002 $g/cm^2$, that of SOBP were 0.010, -0.016, -0.004 $g/cm^2$ and that of output factor were 0.001, -0.001, 0.002 cGy/MU. Conclusion: It is observed that the range, SOBP and output factor of proton beam delivered when respiratory gated proton therapy is being performed have the same beam quality with no significant difference compared to the proton beam which was continuously irradiated. Therefore, this study verified the quality of proton beam delivered when respiratory gated proton therapy and confirmed the accuracy of proton therapy using this.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.43 no.1
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• pp.79-86
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• 2017

This study is related to a lamellar liquid crystal make-up cleansing formulation with a hologram-like unique appearance between two polarizing plates. Make-up cleansing formulations with a lamellar liquid crystal phase have been extensively studied for a long time, but there have been limitations in practical commercialization because of increasing turbidity and viscosity. In this study, to solve this problem, alkyl chains of surfactants were modified to increase the fluidity of the liquid crystal phase, and electrostatic repulsion force was increased by introducing anionic surfactant. The lamellar liquid crystal make-up cleansing formulation which introduced anionic surfactants can easily inhibit crystallization through electrostatic repulsion force, thereby showing excellent stability overtime, maintaining transparent appearance and viscosity. In addition, we have newly introduced an in vitro cleansing evaluation method using fluorescent material and in vivo imaging system (IVIS) for objective and quantitative cleansing ability evaluation. The excellent cleansing ability of lamellar liquid crystal cleansing formulation has been confirmed by newly developed evaluation method. On the other hand, when lamellar liquid crystal make-up cleansing formulation was placed between orthogonally arranged two polarizing plates, a specific pattern like a hologram can be observed. This phenomenon is presumably interpreted as the interference between the visible light passing through the liquid crystal formulation and the lamellar structure. The lamellar structure of cleansing formulation was confirmed by SAXS analysis, exhibiting Bragg spacing ratio of 1 : 2. The lamellar liquid crystal make-up cleansing formulation prepared in this study would be useful for future application in make-up cleansing due to its excellent stability, cleansing ability, and unique hologram-like pattern placed between two polarizing plates.

• The Journal of Korean Society for Radiation Therapy
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• v.30 no.1_2
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• pp.97-105
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• 2018

Purpose : Proton Therapy using Bragg-peak, because it has distinct characteristics in providing maximum dosage for tumor and minimal dosage for normal tissue, a medical imaging system that can quantify changes in patient position or treatment area is of paramount importance to the treatment of protons. The purpose of this research is to evaluate the usefulness of the algorithm by comparing the image matching through the set-up and in-house code through the existing dips program by producing a Matlab-based in-house registration code to determine the error value between dips and DRR to evaluate the accuracy of the existing treatment. Materials and Methods : Thirteen patients with brain tumors and head and neck cancer who received proton therapy were included in this study and used the DIPS Program System (Version 2.4.3, IBA, Belgium) for image comparison and the Eclipse Proton Planning System (Version 13.7, Varian, USA) for patient treatment planning. For Validation of the Registration method, a test image was artificially rotated and moved to match the existing image, and the initial set up image of DIPS program of existing set up process was image-matched with plan DRR, and the error value was obtained, and the usefulness of the algorithm was evaluated. Results : When the test image was moved 0.5, 1, and 10 cm in the left and right directions, the average error was 0.018 cm. When the test image was rotated counterclockwise by 1 and $10^{\circ}$, the error was $0.0011^{\circ}$. When the initial images of four patients were imaged, the mean error was 0.056, 0.044, and 0.053 cm in the order of x, y, and z, and 0.190 and $0.206^{\circ}$ in the order of rotation and pitch. When the final images of 13 patients were imaged, the mean differences were 0.062, 0.085, and 0.074 cm in the order of x, y, and z, and 0.120 cm as the vector value. Rotation and pitch were 0.171 and $0.174^{\circ}$, respectively. Conclusion : The Matlab-based In-house Registration code produced through this study showed accurate Image matching based on Intensity as well as the simple image as well as anatomical structure. Also, the Set-up error through the DIPS program of the existing treatment method showed a very slight difference, confirming the accuracy of the proton therapy. Future development of additional programs and future Intensity-based Matlab In-house code research will be necessary for future clinical applications.