• Journal of Astronomy and Space Sciences
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• v.39 no.3
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• pp.87-98
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• 2022

The Far-UltraViolet (FUV) imager onboard the Ionospheric Connection Explorer (ICON) spacecraft provides two-dimensional limb images of oxygen airglow in the nightside low-latitude ionosphere that are used to determine the oxygen ion density. As yet, no FUV limb imager has been used for climatological analyses of Equatorial Plasma Bubbles (EPBs). To examine the potential of ICON/FUV for this purpose, we statistically investigate small-scale (~180 km) fluctuations of oxygen ion density in its limb images. The seasonal-longitudinal variations of the fluctuation level reasonably conform to the EPB statistics in existing literature. To further validate the ICON/FUV data quality, we also inspect climatology of the ambient (unfiltered) nightside oxygen ion density. The ambient density exhibits (1) the well-known zonal wavenumber-4 signatures in the Equatorial Ionization Anomaly (EIA) and (2) off-equatorial enhancement above the Caribbean, both of which agree with previous studies. Merits of ICON/FUV observations over other conventional data sets are discussed in this paper. Furthermore, we suggest possible directions of future work, e.g., synergy between ICON/FUV and the Global-scale Observations of the Limb and Disk (GOLD) mission.

• Proceedings of the Korea Multimedia Society Conference
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• 2001.06a
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• pp.95-98
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• 2001

본 논문은 뇌의 축방향(axial sect ion)에 대하여 촬영한 뇌의 자기공명 영상(Magnetic Resonance Imaging)을 대상으로 뇌의 영역만을 분리하기 위한 방법을 제안하고 있다. MR영상은 슬라이스마다 다른 분포값을 가지기 때문에 각 슬라이스 별로 조직의 특성을 파악하여 뇌의 영역을 분리하였다. 히스토그램의 명암값 분포를 분석하여 배경과 뇌를 둘러싸고 있는 외피를 제거하고 라벨링(label1ing) 알고리즘을 적용하여 뇌만 분리 할 수 있도록 하는 마스크 영상을 만들어 이것을 이용하여 원영상으로부터 뇌의 영역만을 분리하였다.

• Bulletin of the Korean Chemical Society
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• v.34 no.3
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• pp.957-959
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• 2013

• Radiation Oncology Journal
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• v.16 no.4
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• pp.497-504
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• 1998

Purpose : To evaluate the usefulness of electronic portal imaging device through objective compare of the images acquired using an EPID and a conventional port film Materials and Methods : From Apr. to Oct. 1997, a total of 150 sets of images from 20 patients who received radiation therapy in the pelvis area were evaluated in the Inha University Hospital and Severance Hospital. A dual image recording technique was devised to obtain both electronic portal images and port film images simultaneously with one treatment course. We did not perform double exposure five to ten images were acquired from each patient. All images were acquired from posteroanterior (PA) view except images from two patients. A dose rate of 100-300 Mu/min and a 10-MV X-ray beam were used and 2-10 MUs were required to produce a verification image during treatment. Kodak diagnostic film with metal/film imaging cassette which was located on the top of the EPID detector was used for the port film. The source to detector distance was 140 cm. Eight anatomical landmarks (pelvic brim, sacrum, acetabulum. iliopectineal line, symphysis, ischium, obturator foramen, sacroiliac joint) were assessed. Four radiation oncologist joined to evaluate each image. The individual landmarks in the port film or in the EPID were rated - very clear (1), clear (2), visible (3), not clear (4), not visible (5). Results : Using an video camera based EPID system. there was no difference of image quality between no enhanced EPID images and port film images. However, when we provided some change with window level for the portal image, the visibility of the sacrum and obturator foramen was improved in the portal images than in the port film images. All anatomical landmarks were more visible in the portal images than in the port film when we applied the CLAHE mode enhancement. The images acquired using an matrix ion chamber type EPID were also improved image qualify after window level adjustment. Conclusion : The quality of image acquired using an electronic portal imaging device was comparable to that of the port film. When we used the enhance mode or window level adjustment. the image quality of the EPID was superior to that of the port film. EPID may replace the port film.

• Progress in Medical Physics
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• v.29 no.2
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• pp.53-58
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• 2018

This paper evaluates patient-specific quality assurance (PSQA) in the treatment of small and multiple tumors by the CyberKnife system with fixed collimators, using an ion chamber and EBT3 films. We selected 49 patients with single or multiple brain tumors, and the treatment plans include one to four targets with total volumes ranging from 0.12 cc to 3.74 cc. All PSQA deliveries were performed with a stereotactic dose verification phantom. The A16 microchamber (Standard Imaging, WI, USA) and Gafchromic EBT3 film (Ashland ISP Advanced Materials, NJ, USA) were inserted into the phantom to measure the point dose of the target and the dose distribution, respectively. The film was scanned 1 hr after irradiation by a film digitizer scanner and analyzed using RIT software (Radiological Imaging Technology, CO, USA). The acceptance criteria was <5% for the point dose measurement and >90% gamma passing rate using 3%/3 mm and relative dose difference, respectively. The point dose errors between the calculated and measured dose by the ion chamber were in the range of -17.5% to 8.03%. The mean point dose differences for 5 mm, 7.5 mm, and 10 mm fixed cone size was -11.1%, -4.1%, and -1.5%, respectively. The mean gamma passing rates for all cases was 96.1%. Although the maximum dose distribution of multiple targets was not shown in the film, gamma distribution showed that dose verification for multiple tumors can be performed. The use of the microchamber and EBT3 film made it possible to verify the dosimetric and mechanical accuracy of small and multiple targets. In particular, the correction factors should be applied to small fixed collimators less than 10 mm.

• Bulletin of the Korean Chemical Society
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• v.33 no.1
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• pp.143-148
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• 2012

The photodissociation dynamics of cyclopropyl bromide ($C_3H_5Br$) and cyclobutyl bromide ($C_4H_7Br$) at 234 nm was investigated. A two-dimensional photofragment ion-imaging technique coupled with a [2+1] resonanceenhanced multiphoton ionization scheme was utilized to obtain speed and angular distributions of the nascent $Br(^2P_{3/2})$ and $Br^*(^2P_{1/2})$ atoms. The recoil anisotropies for the Br and $Br^*$ channels were measured to be ${\beta}_{Br}=0.92{\pm}0.03$ and ${\beta}_{Br^*}=1.52{\pm}0.04$ for $C_3H_5Br$ and ${\beta}_{Br}=1.10{\pm}0.03$ and ${\beta}_{Br^*}=1.49{\pm}0.05$ for $C_4H_7Br$. The relative quantum yield for Br was found to be ${\Phi}_{Br}=0.13{\pm}0.03$ and for $C_3H_5Br$ and $C_4H_7Br$, respectively. The soft radical limit of the impulsive model adequately modeled the related energy partitioning. The nonadiabatic transition probability from the 3A' and 4A' potential energy surfaces was estimated and discussed.

• Bulletin of the Korean Chemical Society
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• v.34 no.10
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• pp.2900-2904
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• 2013

We present the synthesis and characterization of DTPA-bis(histidylamide) (1a), DTPA-bis(aspartamide) (1b), and their gadolinium complexes of the type $[Gd(L)(H_2O)]$ (2a:L = 1a; 2b:L = 1b). Thermodynamic stabilities and $R_1$ relaxivities of 2a-b compare well with Omniscan$^{(R)}$, a well-known commercial, extracellular (ECF) MRI CA which adopts the DTPA-bis(amide) framework for the chelate: $R_1$ = 5.5 and 5.1 $mM^{-1}$ for 2a and 2b, respectively. Addition of the Cu(II) ion to a solution containing 2b triggers relaxivity enhancement to raise $R_1$ as high as 15.3 $mM^{-1}$, which corresponds to a 300% enhancement. Such an increase levels off at the concentration beyond two equiv. of Cu(II), suggesting the formation of a trimetallic ($Gd/Cu_2$) complex in situ. Such a relaxivity increase is almost negligible with Zn(II) and other endogenous ions such as Na(I), K(I), Mg(II), and Ca(II). In vivo MR images and the signal-to-noise ratio (SNR) obtained with an aqueous mixture of 2b and Cu(II) ion in an 1:2 ratio demonstrate the potentiality of 2 as a copper responsive MRI CA.

• Bulletin of the Korean Chemical Society
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• v.30 no.12
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• pp.2962-2968
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• 2009

The photodissociation dynamics of 1,2-bromochloroethane ($C_2H_4BrCl$) was investigated near 234 nm. A two-dimensional photofragment ion-imaging technique coupled with a [2+1] resonance-enhanced multiphoton ionization scheme was utilized to obtain speed and angular distributions of the nascent Br($^2P_{3/2}$) and Br${\ast}($^2P_{1/2}$) atoms. The total translational energy distributions for the Br and Br${\ast}$ channels were well characterized by Gaussian functions with average translational energies of 100 and 84 kJ/mol, respectively. The recoil anisotropies for the Br and Br${\ast}$ channels were measured to be ${\beta}$ = 0.49 ${\pm}$ 0.05 for Br and 1.55 ${\pm}$ 0.05 for Br${\ast}$. The relative quantum yield for Br${\ast}$ was found to be ${\Phi}_{Br{\ast}}$ = 0.33 ${\pm}$ 0.03. The probability of nonadiabatic transition between A' states was estimated to be 0.46. The relevant nonadiabatic dynamics is discussed in terms of interaction between potential energy surfaces in Cs symmetry.

• Journal of the Korean Society of Radiology
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• v.9 no.4
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• pp.205-211
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• 2015

At a recent medical imaging technology, the major issue of X-ray diagnosis in breast cancer is the early detection of breast cancer and low patient's exposure dose. As one of studies to acquire a monochromatic X-ray, Technologies using multilayer mirror had been preceded. However, a uniform multilayer mirror that consists of uniform thin-film thickness can acquire a monochromatic X-ray only in the partial area corresponds to angle of incidence of white X-ray, so there are limits for X-ray imaging technology applications. In this study, we designed laterally graded multilayer mirror(below GML) that reflects same monochromatic X-ray over the entire area of thin-film mirror, which have the the thickness of the linear gradient that correspond to angle of incidence of white X-ray. By using ion-beam sputtering system added the mask control system we fabricated a GML which has size of $100{\times}100mm^2$. The GML is designed to achieve the monochromatic X-ray of 17.5kev energy and has thin-film thickness change from 4.62nm to 6.57nm(3.87nm at center). It reflects the monochromatic X-ray with reflectivity of more than 60 percent, FWHM of below 2.6keV and X-ray beam width of about 3mm. The monochromatic X-ray corresponded to 17.5keV using GML would have wide application in development of mammography system with high contrast and low dose.

• Biomolecules & Therapeutics
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• v.25 no.5
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• pp.497-503
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• 2017

Recent reports claimed that glucosylsphingosine (GS) is highly accumulated and specifically evoking itch-scratch responses in the skins of atopic dermatitis (AD) patients. However, it was unclear how GS can trigger itch-scratch responses, since there were no known molecular singling pathways revealed yet. In the present study, it was verified for the first time that GS can activate mouse serotonin receptor 2a (mHtr2a) and 2b (mHtr2b), but not 2c (mHtr2c) that are expressed in HEK293T cells. Specifically, effects of GS on all mouse serotonin receptor 2 subfamily were evaluated by calcium imaging techniques. The GS-induced intracellular calcium increase was dose-dependent, and antagonists such as ketanserin (Htr2a antagonist) and RS-127445 (Htr2b antagonist) significantly blocked the GS-induced responses. Moreover, the proposed GS-induced responses appear to be mediated by phospholipase C (PLC), since pretreatment of a PLC inhibitor U-73122 abolished the GS-induced responses. Additionally, the GS-induced calcium influx is probably mediated by endogenous TRPC ion channels in HEK293T cells, since pretreatment of SKF-96365, an inhibitor for TRPC, significantly suppressed GS-induced response. In conclusion, the present study revealed for the first time that GS can stimulate mHtr2a and mHtr2b to induce calcium influx, by utilizing PLC-dependent pathway afterwards. Considering that GS is regarded as a pruritogen in AD, the present study implicates a novel GS-induced itch signaling pathway.