• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.15 no.9
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• pp.906-913
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• 2004

FFT algorithm is the most popular ISAR imaging technique from radar data. It requires polar formatting technique to make a focused image of the target as MTRC(Moving Through Resolution Cell) causes a blurred image when the data is from the wide azimuth angle. But there exits the angle limit for the application of the polar formatting and we cannot obtain clear images if the range of the azimuth angle is too wide to process with polar, formatting. This paper analyses the relative merits of the polar formatting algorithm accompanied by interpolation to the CDT algorithm that needs not the interpolation.

• The Korean Journal of Nuclear Medicine
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• v.30 no.4
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• pp.532-540
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• 1996

목적 : 종양세포의 증식을 평가하기 위해 radiofluorinated ethyluracil (FEU)과 deoxyadenosine analogue(FAD)를 합성하여 종양의 영상화를 시도하였다. 대상 및 방법 : 5-(2-Fluoroethyl)uracil ([$^{18}F$]FEU)은 2, 4-dimethoxy-5-(2-hydroxyethyl) pyrimidine을 $K^{18}F$와 처리한 후 HBr로 가수분해하여 얻었으며 Fluorodeoxyadenosine은 adenosine의 triacetylated analogue를 $K^{18}F$와 처리하여 얻었다. 생물학적 조직분포는 유방암 세포(13762 NF, 100,000 cells per rat, im)를 쥐에 접종한 후 0.5, 1, 2 및 4시간에 주요장기를 적출하여 %ID/g을 측정하고 자가방사영상은 방사성의약품 투여 45분 후에 얻었다. PET 영상은 VX-2 종양을 접종한 가토를 이용하여 얻었다. In vitro cell proliferation assay는 사람의 말초단핵구를 이용하였다. 결 과 : In vitro assay상 ([$^{18}F$]FEU는 세포증식시 DNA/RNA에 결합함을 시사하였다. ([$^{18}F$]FAD와 ([$^{18}F$]FEU의 종양/비종양 방사능 섭취비는 시간경과에 따라 증가하였으며 ([$^{18}F$]FAD와 ([$^{18}F$]FEU를 이용한 자가방사영상과 ([$^{18}F$]FEU를 이용한 PET 영상에서 종양을 잘 관찰할 수 있었다. 결 론 : ([$^{18}F$]FAD 및 ([$^{18}F$]FEU를 이용하여 종양세포의 증식을 PET 영상에서 평가할 수 있으리라 사료된다.

• Investigative Magnetic Resonance Imaging
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• v.23 no.4
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• pp.367-373
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• 2019

Yolk sac tumors are rare malignant germ cell neoplasms that usually arise from the gonads. Extragonadal yolk sac tumors (EGYSTs) frequently occur in the mediastinum in post-pubertal females. EGYSTs in the pelvis are extremely rare, and to date, only thirteen cases have been reported in the English literature. Among them, the primary EGYST of the pelvic peritoneum in post-pubertal females has only been reported in ten cases. The present case describes a 26-year-old female diagnosed with primary peritoneal yolk sac tumor located in the rectouterine pouch. We report clinical and tumor imaging features, including ultrasound, computed tomography (CT), magnetic resonance images (MRI), positron emission tomography-computed tomography (PET-CT), and present a review of the literature.

• Molecules and Cells
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• v.42 no.4
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• pp.356-362
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• 2019

The binding of MS2 bacteriophage coat protein (MCP) to MS2 binding site (MBS) RNA stem-loop sequences has been widely used to label mRNA for live-cell imaging at single-molecule resolution. However, concerns have been raised recently from studies with budding yeast showing aberrant mRNA metabolism following the MS2-GFP labeling. To investigate the degradation pattern of MS2-GFP-labeled mRNA in mammalian cells and tissues, we used Northern blot analysis of ${\beta}$-actin mRNA extracted from the Actb-MBS knock-in and $MBS{\times}MCP$ hybrid mouse models. In the immortalized mouse embryonic cell lines and various organ tissues derived from the mouse models, we found no noticeable accumulation of decay products of ${\beta}$-actin mRNA compared with the wild-type mice. Our results suggest that accumulation of MBS RNA decay fragments does not always happen depending on the mRNA species and the model organisms used.

• Korean Journal of Clinical Laboratory Science
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• v.54 no.1
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• pp.1-8
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• 2022

Erythrocyte sedimentation rate (ESR) evaluation is a useful tool for monitoring disease activity in various inflammatory and non-inflammatory conditions. ESR is known to be influenced by a multitude of confounding factors. The present study aimed to assess the possible determinants of the ESR and its relationship with various risk factors involved in ischemic stroke. ESR and other hematological and biochemical parameters were investigated in 163 ischemic stroke patients (107 males and 56 females) selected based on imaging techniques including magnetic resonance imaging (MRI) or computed tomography (CT) scans. Statistical analysis was performed using the SPSS 16.0 software. Linear regression analysis showed a significant inverse relationship of hemoglobin (Hb) and hematocrit or packed cell volume (PCV) (P<0.001 for females; P<0.01 for males) with the ESR. It was observed that the red blood cell (RBC) count was not strongly correlated with the ESR (P<0.05 for both males and females). It was also observed that sex significantly affected the variables determining the ESR levels, whereas age had no effect. Gender differences were also observed with respect to Hb, RBC, PCV, mean corpuscular hemoglobin (MCH), mean corpuscular hemoglobin concentration (MCHC), and ESR. The possible determinants of higher ESR levels in ischemic stroke may be sex, Hb, hematocrit, and RBC count, but the role of other clinical and laboratory parameters cannot be underestimated.

• Clinical and Experimental Reproductive Medicine
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• v.49 no.4
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• pp.225-238
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• 2022

The ultimate goal of human assisted reproductive technology is to achieve a healthy pregnancy and birth, ideally from the selection and transfer of a single competent embryo. Recently, techniques for efficiently evaluating the state and quality of preimplantation embryos using time-lapse imaging systems have been applied. Artificial intelligence programs based on deep learning technology and big data analysis of time-lapse monitoring system during in vitro culture of preimplantation embryos have also been rapidly developed. In addition, several molecular markers of the secretome have been successfully analyzed in spent embryo culture media, which could easily be obtained during in vitro embryo culture. It is also possible to analyze small amounts of cell-free nucleic acids, mitochondrial nucleic acids, miRNA, and long non-coding RNA derived from embryos using real-time polymerase chain reaction (PCR) or digital PCR, as well as next-generation sequencing. Various efforts are being made to use non-invasive evaluation of embryo quality (NiEEQ) to select the embryo with the best developmental competence. However, each NiEEQ method has some limitations that should be evaluated case by case. Therefore, an integrated analysis strategy fusing several NiEEQ methods should be urgently developed and confirmed by proper clinical trials.

• Korean Journal of Head & Neck Oncology
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• v.40 no.1
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• pp.15-17
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• 2024

Clear cell carcinoma is a rare variant of salivary gland carcinoma, and its occurrence in the tongue base is even rarer. We present a case of a 55-year-old female patient with clear cell carcinoma of the tongue base. The patient initially presented with a 3-month history of palpable tongue mass, leading to her visit to the otolaryngology outpatient clinic. The patient underwent a complete resection of the tumor under general anesthesia. Postoperative follow-up imaging studies showed no evidence of recurrence. This case report highlights the diagnostic and management challenges associated with clear cell carcinoma of tongue base and demonstrates that a high index of suspicion is required to diagnose clear cell caricnoma, given its rarity and overlapping features with other clear cell neoplasms.

• The Korean Journal of Nuclear Medicine
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• v.34 no.1
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• pp.99-105
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• 2000

Computed tomography (CT) seems to be the best imaging modality to diagnose an enterovesical fistula, but is not always able to demonstrate enterovesical fistula itself. In this case report, we present Tc-99m HMPAO white blood cell (WBC) scintigraphic findings of an enterovesical fistula complicating Crohn's disease. A 22 year-old male presented with a one-month history of urinary symptoms such as dysuria, hematuria, and frequency. The patient had intermittent right lower quadrant pain, diarrhea and hematochezia. Enterovesical fistula was highly suggestive in pelvic CT which showed air density in the urinary bladder, but cystoscopy failed to find an opening of the fistula. Tc-99m HMPAO WBC scintigraphy for evaluation of inflammatory bowel disease incidentally demonstrated enterovesical fistular tract. Crohn's disease was later confirmed by histologic examination of the surgical specimen. In our patient, Tc-99m HMPAO WBC imaging was helpful in determining the location of the fistula as well as assessing the disease activity and extent of the Crohn's disease.

• Bulletin of the Korean Chemical Society
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• v.34 no.3
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• pp.815-819
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• 2013

Micropatterns of streptavidin and human epidermal carcinoma A431 cells were successfully imaged, as received and without any labeling, using cluster $Au_3{^+}$ ion beam-based time-of-flight secondary ion mass spectrometry (TOF-SIMS) together with a principal component analysis (PCA). Three different analysis ion beams ($Ga^+$, $Au^+$ and $Au_3{^+}$) were compared to obtain label-free TOF-SIMS chemical images of micropatterns of streptavidin, which were subsequently used for generating cell patterns. The image of the total positive ions obtained by the $Au_3{^+}$ primary ion beam corresponded to the actual image of micropatterns of streptavidin, whereas the total positive-ion images by $Ga^+$ or $Au^+$ primary ion beams did not. A PCA of the TOF-SIMS spectra was initially performed to identify characteristic secondary ions of streptavidin. Chemical images of each characteristic ion were reconstructed from the raw data and used in the second PCA run, which resulted in a contrasted - and corrected - image of the micropatterns of streptavidin by the $Ga^+$ and $Au^+$ ion beams. The findings herein suggest that using cluster-ion analysis beams and multivariate data analysis for TOF-SIMS chemical imaging would be an effectual method for producing label-free chemical images of micropatterns of biomolecules, including proteins and cells.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.08a
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• pp.53-53
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• 2011

This paper describes results for surface and bulk characterization of the most promising thin film solar cell material for high performance devices, (Ag,Cu) (In,Ga) Se2 (ACIGS). This material in particular exhibits a range of exotic behaviors. The surface and general materials science of the material also has direct implications for the operation of solar cells based upon it. Some of the techniques and results described will include scanning probe (AFM, STM, KPFM) measurements of epitaxial films of different surface orientations, photoelectron spectroscopy and inverse photoemission, Auger electron spectroscopy, and more. Bulk measurements are included as support for the surface measurements such as cathodoluminescence imaging around grain boundaries and showing surface recombination effects, and transmission electron microscopy to verify the surface growth behaviors to be equilibrium rather than kinetic phenomena. The results show that the polar close packed surface of CIGS is the lowest energy surface by far. This surface is expected to be reconstructed to eliminate the surface charge. However, the AgInSe2 compound has yielded excellent atomic-resolution images of the surface with no evidence of surface reconstruction. Similar imaging of CuInSe2 has proven more difficult and no atomic resolution images have been obtained, although current imaging tunneling spectroscopy images show electronic structure variations on the atomic scale. A discussion of the reasons why this may be the case is given. The surface composition and grain boundary compositions match the bulk chemistry exactly in as-grow films. However, the deposition of the heterojunction forming the device alters this chemistry, leading to a strongly n-type surface. This also directly explains unpinning of the Fermi level and the operation of the resulting devices when heterojunctions are formed with the CIGS. These results are linked to device performance through simulation of the characteristic operating behaviors of the cells using models developed in my laboratory.