• Applied Chemistry for Engineering
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• v.33 no.1
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• pp.17-27
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• 2022

Fluorescence imaging is widely used to image cells or small animals due to its high temporal and spatial resolution. Because conventional fluorescence imaging uses visible light, the penetration depth of light within the tissue is low, phototoxicity may occur due to visible light, and the detection sensitivity is lowered due to interference by background autofluorescence. In order to overcome this limitation, long-wavelength light should be used, and fluorescence imaging using near-infrared-I (NIR-I) in the region of 700~900 nm has been developed. To further improve imaging quality, researchers are interested in using a longer wavelength light, near-infrared-II (NIR-II) ranging from 1000 to 1700 nm. In the NIR-II region, light scattering is further minimized, and the penetration depth of light in the tissue is improved up to about 10 mm, and autofluorescence of the tissue is reduced, enabling high sensitivity and resolution fluorescence imaging. In this review, among various NIR-II fluorescence imaging probes, inorganic nanoparticle-based probes with excellent photostability and easily tunable emission wavelength were described, focusing on single-walled carbon nanotubes, quantum dots, and lanthanide nanoparticles.

• Tuberculosis and Respiratory Diseases
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• v.60 no.6
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• pp.645-652
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• 2006

Objective: Patients with lung cancer have a relative high risk of developing secondary primary lung cancers. This study examined the additional value of autofluorescence bronchoscopy (AFB) for diagnosing synchronous lung cancers and premalignant lesions. Methods: Patients diagnosed with lung cancer from January 2005 to December 2005 were enrolled in this study. The patients underwent a lung cancer evaluation, which included white light bronchoscopy (WLB), followed by AFB. In addition to the primary lesions, any abnormal or suspicious lesions detected during WLB and AFB were biopsied. Results: Seventy-six patients had non-small cell lung cancer (NSCLC) and 23 had small cell lung cancer (SCLC). In addition to the primary lesions, 84 endobronchial biopsies were performed in 46 patients. Five definite synchronous cancerous lesions were detected in three patients with initial unresectable NSCLC and in one with SCLC. The secondary malignant lesions found in two patients were considered metastatic because of the presence of mediastinal nodes or systemic involvement. One patient with an unresectable NSCLC, two with a resectable NSCLC, and one with SCLC had severe dysplasia. The detection rate for cancerous lesions by the clinician was 6.0% (6/99) including AFB compared with 3.0% (3/99) with WLB alone. The prevalence of definite synchronized cancer was 4.0% (4/99) after using AFB compared with 2.0% (2/99) before, and the staging-up effect was 1.0% (1/99) after AFB. Since the majority of patients were diagnosed with advanced disease, the subjects with newly detected cancerous lesions did not have their treatment plans altered, except for one patient with a stage-up IV NSCLC who did not undergo radiotherapy. Conclusions: Additional AFB is effective in detecting early secondary cancerous lesions and is a more precise tool in the staging workup of patients with primary lung cancer than with WLB alone.

• Journal of the Korean Society of Visualization
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• v.11 no.2
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• pp.41-45
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• 2013

Two-photon microscopy (TPM) is minimally-invasive 3D fluorescence microscopy based on nonlinear excitation, and TPM can visualize cellular structures based on auto-fluorescence. Line-scanning TPM is one of high-speed TPM methods without sacrificing the image resolution by using spatial and temporal focusing. In this paper, we developed line-scanning TPM based on spatial and temporal focusing for auto-fluorescence imaging by exciting the tryptophan. Laser source for this system was an optical parametric oscillator (OPO) and it made near 570 nm femtosecond pulse laser. It had 200fs pulse width and 1.72 nm bandwidth, so that the achievable depth resolution was 2.41um and field of view (FOV) is 10.8um. From the characterization, our system has 3.0 um depth resolution and 12.3 um FOV. We visualized fixed leukocyte cell sample and compared with point scanning system.

• Korean Chemical Engineering Research
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• v.60 no.3
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• pp.398-406
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• 2022

The outer membrane of Gram-negative bacteria is the outermost layer of cellular environment in which numerous biophysical and biochemical processes are in action sustaining viability. Advances in cell engineering enable modification of bacterial genetic information that subsequently alters membrane physiology to adapt bacteria to specific purposes. Surface display of a functional molecule on the outer membranes is one of strategies that directs host cells to respond to a specific extracellular matter or stimulus. While intracellular expression of a functional peptide or protein fused to a membrane-anchoring motif is commonly practiced for surface display, the method is not readily applicable to exogenous or large proteins inexpressible in bacteria. Chemical conjugation at reactive groups naturally occurring on the membrane might be an alternative, but often compromises fitness due to non-specific modification of essential components. Herein, we demonstrated two distinct approaches that enable site-specific decoration of the outer membrane with a fluorescent agent in Escherichia coli. An unnatural amino acid genetically incorporated in a surface-exposed peptide could act as a chemoselective handle for bioorthogonal dye labeling. A surface-displayed α-helical domain originating from a part of a selected heterodimeric coiled-coil complex could recruit and anchor a green fluorescent protein tagged with a complementary α-helical domain to the membrane surface in a site- and hetero-specific manner. These methods hold a promise as on-demand tools to confer new functionalities on the bacterial membranes.

• The Journal of Korean Academy of Prosthodontics
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• v.59 no.3
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• pp.271-280
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• 2021

Purpose. The aim of this study was to evaluate the relationship between the patient's occlusion and a cracked tooth by using T-scan occlusal analysis and a quantitative light-induced fluorescence (QLF) technology. Materials and methods. This study was carried out on 51 patients having cracked teeth between January, 2019 and December, 2020. The tooth crack was determined with a Q-ray pen and QLF parameters (ΔF_max and ΔR_max) were obtained by a Q-ray software. T-scan tests were conducted to all subjects and then, the occlusal force and disclosing time were analyzed. Mann-Whitney U test was performed to compare the occlusal force and disclosing time between cracked teeth groups and contra-lateral normal teeth groups (α = .05). Mann-Whitney U test was performed to compare ΔF_max and ΔR_max according to the results of cold/bite tests (α = .05). A Spearman correlation analysis was run to determine the relationship between ΔF_max or ΔR_max and occlusal force or disclosing time (α=.05). Results. The mean occlusal force and disclosing time were significantly higher on cracked teeth than on normal teeth (P < .05). The ΔF_max or ΔR_max were not significantly different according to the results of cold/bite tests (P > .05). There was no correlation between ΔF_max or ΔR_max and occlusal force or disclosing time (P > .05). Conclusion. There was a significant relationship between occlusion and cracked tooth syndrome. QLF has the potential to be a valuable tool for the diagnosis of tooth crack in clinical practice.

• International journal of thyroidology
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• v.11 no.2
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• pp.92-98
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• 2018

Intraoperative identification and localization of parathyroid glands are crucial step in preventing postoperative hypocalcemia during thyroid and parathyroid surgery. If there is a method to predict the parathyroid's location rather than detecting and verifying with naked eye, it would make the operator easier to find and identify the parathyroid. Recently, near-infrared light imaging technologies have been introduced in the fields of thyroid and parathyroid surgery to predict the localization of the parathyroid. These are being conducted in two ways: autofluorescence imaging with a unique intrinsic fluorophore in the parathyroid tissues and fluorescence imaging with external fluorescence materials specially absorbed into parathyroid tissues. We are suggest that parathyroid glands can be detected by surgeon with NIR autofluorescence imaging even if they are covered by fibrofatty tissues before they are detected by surgeon's naked eye. These novel techniques are very useful to identify and preserve parathyroid glands during thyroidectomy. In this article, we reviewed the latest papers that describe autofluorescence imaging and exogenous ICG fluorescence imaging of parathyroid glands during thyroid and parathyroid surgery.

• Journal of the Microelectronics and Packaging Society
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• v.29 no.4
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• pp.55-61
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• 2022

There is a major interest in diagnostic technology for multiple cancers worldwide. In order to reduce the difficulty of cancer diagnosis, a liquid biopsy technology based on a microfluidic device using trace amounts of biofluids such as blood is being studied. And optical biosensing, which measures the concentration of analytes through fluorescence imaging using biofluids, requires various strategies to improve sensitivity, and specialists and equipment are needed to carry out these strategies. This leads to an increase in diagnostic and production costs, and it is necessary to develop a technology to solve this problem. In this paper, we design and propose a fluorescent multi-cancer diagnostic sensing platform structure that implements passive self-separation technology and molecular recognition activation functions by fluid mixing, only with the geometry and microfluidic phenomena of microchannels based on self-driven flow by capillary force. In order to check the parameters affecting the performance of the plasma separation part of the designed sensor, the hydrodynamic diameter of the channel and the viscosity of the fluid were set as variables to confirm the formation of plasma separation flow through simulation. And finally, we propose an optimal sensor platform structure.

• Nuclear Medicine and Molecular Imaging
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• v.43 no.5
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• pp.468-477
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• 2009

Purpose: Hydrodynamic-based procedure is a simple and effective gene delivery method to lead a high gene expression in liver tissue. Non-invasive imaging reporter gene system has been used widely with herpes simplex virus type 1 thymidine kinase (HSV1-tk) and its various substrates. In the present study, we investigated to image the expression of HSV1-tk gene with 5-(2-iodovinyD-2'-deoxyuridine (IVDU) in mouse liver by the hydrodynamicbased procedure. Materials and Methods: HSV1-tk or enhanced green fluorescence protein (EGFP) encoded plasmid DNA was transferred into the mouse liver by hydrodynaminc injection. At 24 h post-injection, RT-PCR, biodistribution, fluorescence imaging, nuclear imaging and digital wholebody autoradiography (DWBA) were performed to confirm transferred gene expression. Results: In RT-PCR assay using mRNA from the mouse liver, specific bands of HSV1-tk and EGFP gene were observed in HSV1-tk and EGFP expressing plasmid injected mouse, respectively. Higher uptake of radiolabeled IVDU was exhibited in liver of HSV1-tk gene transferred mouse by biodistribution study. In fluorescence imaging, the liver showed specific fluorescence signal in EGFP gene transferred mouse. Gamma-camera image and DWBA results showed that radiolabeled IVDU was accumulated in the liver of HSV1-tk gene transferred mouse. Conclusion: In this study, hydrodynamic-based procedure was effective in liver-specific gene delivery and it could be quantified with molecular imaging methods. Therefore, co-expression of HSV1-tk reporter gene and target gene by hydrodynamic-based procedure is expected to be a useful method for the evaluation of the target gene expression level with radiolabeled IVDU.

• Tuberculosis and Respiratory Diseases
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• v.61 no.3
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• pp.207-213
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• 2006

기존의 폐암 발생의 고위험군(나이. 흡연력, $FEV_1$, 가족력, 직업적 발암물질의 노출력, 기존의 폐암 및 두경부 종양)에 대한 저선량 나선식 CT와 기관지 내시경 검사로 선별 검사 시 폐암의 유병률은 높아야 2%내외이고 대부분 그보다 낮은 것으로 알려져 있다. 특이도는 49-90%, 양성예측률은 10%이하로 선별검사 시 불필요한 검사를 초래하고 그에 따른 이환률과 사망률을 증가시키며 비용적인 문제를 야기하는 것으로 알려져 있다. 이에 기존의 고위험군에 대해 대상 환자를 더욱 더 좁힐 필요가 있으며, 이는 실제 임상적으로 이용 가능한 생물학적 표지자의 개발의 필요성이 있다고 하겠다. 그러나 현재까지 알려진 폐암조기검진에 대한 각종 진단 수기 중애서 상기의 3가지 방법(저선량 MDCT, 자가형광기관지경 및 객담내 MAGE)을 한꺼번에 시행하는 program은 비용적인 문제는 있지만 시도해 볼 만한 방법이라고 생각된다.

• Journal of The Korean Ophthalmological Society
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• v.59 no.12
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• pp.1190-1194
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• 2018

Purpose: We report a case of unilateral, focal, pigmented paravenous retinochoroidal atrophy (PPRCA). Case summary: A 46-year-old female visited our clinic in complaint of a vague problem with her right eye identified during a general medical examination. The visual acuity (without correction) of both eyes was 1.0. Slit-lamp examination of both eyes revealed no specific signs. Fundus examination of the right eye revealed focal, bony-spicule-shaped retinochoroidal atrophy with pigmentation along the course of the superior retinal vein. A fundus autofluorescence examination revealed principally hypofluorescence with some hyperfluorescence at the margin of the atrophic retinochoroidal lesion. Optical coherence tomography revealed mixed clumping and atrophy of the retinal pigment epithelium (RPE) layer and thinning of the choriocapillaris layer. Fluorescence angiography revealed a window defect and blockage at the site of the lesion (the fluorescent material did not enter the lesion). The site of the window defect was in correlation with the atrophic RPE region. The site of the blockage at lesion also matched with the site of the regional pigment clumping. No definite leakage was observed. Conclusions: To the best of our knowledge, this is the first case of unilateral focal PPRCA reported from Korea.