• KSTLE International Journal
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• v.1 no.2
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• pp.69-75
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• 2000

The paper compares topography, phase contrast and force spectroscopy in atomic force microscopy data for evaluating the microheterogeneity of surface layer. The worn surface of ion-plated TiN coating was measured using both a laboratory-built and a commercial AFM. The results of analysis revealed structural and micromechanical heterogeneity of the worn surfaces. We demonstrated that the phase image allows relatively qualitative estimation of elastic modulus of the sample surface. The tribolayer formed in the worn surface possessed much lower stiffness than the original coating. It is shown that the most stable phase imaging is provided with a stiff cantilever. In this case, phase contrast is well conditioned, first of all, by microheterogeneity of elastic properties of the investigated surfaces. In this study an attempt was also made to correlate the results of phase imaging with that of the farce spectroscopy. The joint analysis of information on the surface properties obtained by the phase imaging and quantitative data measured with the force spectroscopy methods allows a better understanding of the nature of the surface micromechanical heterogeneity.

• Biomolecules & Therapeutics
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• v.19 no.2
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• pp.149-154
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• 2011

Matrix assisted laser desorption ionization (MALDI) mass spectrometry is commonly used to analyze biological molecules such as proteins, peptides and lipids from cells or tissue. Recently MALDI Imaging mass spectrometry (IMS) has been widely applied for the identification of different drugs and their metabolites in tissue. This special feature has made MALDI-MS a common choice for investigation of the molecular histology of pathological samples as well as an important alternative to other conventional imaging methods. The basic advantages of MALDI-IMS are its simple technique, rapid acquisition, increased sensitivity and most prominently, its capacity for direct tissue analysis without prior sample preparation. Moreover, with ms/ms analysis, it is possible to acquire structural information of known or unknown analytes directly from tissue sections. In recent years, MALDI-IMS has made enormous advances in the pathological field. Indeed, it is now possible to identify various changes in biological components due to disease states directly on tissue as well as to analyze the effect of treated drugs. In this review, we focus on the advantages of MALDI tissue imaging over traditional methods and highlight some motivating findings that are significant in pathological studies.

• Applied Microscopy
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• v.46 no.3
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• pp.134-139
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• 2016

Detailed structural and molecular imaging of intact organs has incurred academic interest because the associated technique is expected to provide innovative information for biological investigation and pathological diagnosis. The conventional methods for volume imaging include reconstruction of images obtained from serially sectioned tissues. This approach requires intense manual work which involves inevitable uncertainty and much time to assemble the whole image of a target organ. Recently, effective tissue clearing techniques including CLARITY and ACT-PRESTO have been reported that enables visualization of molecularly labeled structures within intact organs in three dimensions. The central principle of the methods is transformation of intact tissue into an optically transpicuous and macromolecule permeable state without loss of intrinsic structural integrity. The rapidly evolving protocols enable morphological analysis and molecular labeling of normal and pathological characteristics in large assembled biological systems with single-cell resolution. The deep tissue volume imaging will provide fundamental information about mutual interaction among adjacent structures such as connectivity of neural circuits; meso-connectome and clinically significant structural alterations according to pathologic mechanisms or treatment procedures.

• Korean Journal of Radiology
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• v.25 no.2
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• pp.189-198
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• 2024

Objective: To investigate the prognostic utility of radiomics features extracted from ¹⁸F-fluorodeoxyglucose (FDG) PET/CT combined with clinical factors and metabolic parameters in predicting progression-free survival (PFS) and overall survival (OS) in individuals diagnosed with extranodal nasal-type NK/T cell lymphoma (ENKTCL). Materials and Methods: A total of 126 adults with ENKTCL who underwent ¹⁸F-FDG PET/CT examination before treatment were retrospectively included and randomly divided into training (n = 88) and validation cohorts (n = 38) at a ratio of 7:3. Least absolute shrinkage and selection operation Cox regression analysis was used to select the best radiomics features and calculate each patient's radiomics scores (RadPFS and RadOS). Kaplan-Meier curve and Log-rank test were used to compare survival between patient groups risk-stratified by the radiomics scores. Various models to predict PFS and OS were constructed, including clinical, metabolic, clinical + metabolic, and clinical + metabolic + radiomics models. The discriminative ability of each model was evaluated using Harrell's C index. The performance of each model in predicting PFS and OS for 1-, 3-, and 5-years was evaluated using the time-dependent receiver operating characteristic (ROC) curve. Results: Kaplan-Meier curve analysis demonstrated that the radiomics scores effectively identified high- and low-risk patients (all P < 0.05). Multivariable Cox analysis showed that the Ann Arbor stage, maximum standardized uptake value (SUVmax), and RadPFS were independent risk factors associated with PFS. Further, β2-microglobulin, Eastern Cooperative Oncology Group performance status score, SUVmax, and RadOS were independent risk factors for OS. The clinical + metabolic + radiomics model exhibited the greatest discriminative ability for both PFS (Harrell's C-index: 0.805 in the validation cohort) and OS (Harrell's C-index: 0.833 in the validation cohort). The time-dependent ROC analysis indicated that the clinical + metabolic + radiomics model had the best predictive performance. Conclusion: The PET/CT-based clinical + metabolic + radiomics model can enhance prognostication among patients with ENKTCL and may be a non-invasive and efficient risk stratification tool for clinical practice.

• The Korean Journal of Applied Statistics
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• v.34 no.2
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• pp.127-139
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• 2021

Independent Component Analysis is a popular statistical method to separate independent signals from the mixed data, and Group Independent Component Analysis is an its multi-subject extension of Independent Component Analysis. It has been applied Functional Magnetic Resonance Imaging data and provides promising results. However, classical Group Independent Component Analysis works poorly when outliers exist on data which is frequently occurred in Magnetic Resonance Imaging scanning. In this study, we propose a robust version of the Group Independent Component Analysis based on ROBPCA. Through the numerical studies, we compare proposed method to the conventional method, and verify the robustness of the proposed method.

• The Journal of Korean Academy of Prosthodontics
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• v.38 no.3
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• pp.291-309
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• 2000

Statement of problem. There were several studies on the effects of irradiation to peri-implant bone tissue. However, no clear biological effect of irradiation on peri-implant bone tissue was reported yet. Purpose. This study compared the effect of irradiation on the surrounding tissue of a HA-coated implant fixture with controls. Material and methods. 6 Steri-Oss implants were implanted into the femur of 6 mongrels. The implanted dogs were divided into three groups and received irradiation. After 1 month, 2months and 4 months healing period, the histologic examination and mobility test and digital radiographic imaging analyses were performed to compare the control and experimental group respectively. Results. The irradiated group showed slower healing than control group in light microscopic observations. The mobility test demonstrated significant less number (Periotest) in control group than that of irradiated groups. The digital radiographic imaging analysis showed that the bone density of irradiated group was higher than control group. Conclusion. Generally, control group showed favorable biological response and less mobility than irradiated group. The conflict result of bone density value were measured by the digital radiographic imaging analysis. The digital radiographic imaging analysis needs more research in future.

• Fisheries and Aquatic Sciences
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• v.14 no.3
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• pp.218-225
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• 2011

Dual frequency identification sonar (DIDSON) is an imaging sonar that has been used for numerous fisheries investigations in a diverse range of freshwater and marine environments. The main purpose of DIDSON is fish counting, fish sizing, and fish behavioral studies. DIDSON records video-quality data, so processing power for handling the vast amount of data with high speed is a priority. Therefore, a semiautomated analysis of DIDSON data for fish counting, sizing, and fish behavior in Echoview (fisheries acoustic data analysis software) was accomplished using testing data collected on the Rakaia River, New Zealand. Using this data, the methods and algorithms for background noise subtraction, image smoothing, target (fish) detection, and conversion to single targets were precisely illustrated. Verification by visualization identified the resulting targets. As a result, not only fish counts but also fish sizing information such as length, thickness, perimeter, compactness, and orientation were obtained. The alpha-beta fish tracking algorithm was employed to extract the speed, change in depth, and the distributed depth relating to fish behavior. Tail-beat pattern was depicted using the maximum intensity of all beams. This methodology can be used as a template and applied to data from BlueView two-dimensional imaging sonar.

• The Korean Journal of Physiology and Pharmacology
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• v.23 no.4
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• pp.237-249
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• 2019

Confirming the direct link between neural circuit activity and animal behavior has been a principal aim of neuroscience. The genetically encoded calcium indicator (GECI), which binds to calcium ions and emits fluorescence visualizing intracellular calcium concentration, enables detection of in vivo neuronal firing activity. Various GECIs have been developed and can be chosen for diverse purposes. These GECI-based signals can be acquired by several tools including two-photon microscopy and microendoscopy for precise or wide imaging at cellular to synaptic levels. In addition, the images from GECI signals can be analyzed with open source codes including constrained non-negative matrix factorization for endoscopy data (CNMF_E) and miniscope 1-photon-based calcium imaging signal extraction pipeline (MIN1PIPE), and considering parameters of the imaged brain regions (e.g., diameter or shape of soma or the resolution of recorded images), the real-time activity of each cell can be acquired and linked with animal behaviors. As a result, GECI signal analysis can be a powerful tool for revealing the functions of neuronal circuits related to specific behaviors.

• Mass Spectrometry Letters
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• v.14 no.4
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• pp.147-152
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• 2023

The increasing demand for two-dimensional imaging analysis using optical or electronic microscopic techniques has led to an increase in the use of simple one-dimensional and two-dimensional mass spectrometry imaging. Among these imaging methods, secondary-ion mass spectrometry (SIMS) has the best spatial resolution using a primary ion beam with a relatively insignificant beam diameter. Until recently, SIMS, which uses high-energy primary ion beams, has not been used to analyze molecules. However, owing to the development of cluster ion beams, it has been actively used to analyze various organic molecules from the surface. Researchers and commercial SIMS companies are developing cluster ion beams to analyze biological samples, including amino acids, peptides, and proteins. In this study, a water droplet ion beam for surface analysis was realized. Water droplets ions were generated via electrospraying in a vacuum without desolvation. The generated ions were accelerated at an energy of 10 keV and collided with the target sample, and secondary ion mass spectra were obtained for the generated ions using ToF-SIMS. Thus, the proposed water droplet ion-beam device showed potential applicability as a primary ion beam in SIMS.

• Molecules and Cells
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• v.41 no.7
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• pp.676-683
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• 2018

Cilia are highly specialized antennae-like organelles that extend from the cell surface and act as cell signaling hubs. Intraflagellar transport (IFT) is a specialized form of intracellular protein trafficking that is required for the assembly and maintenance of cilia. Because cilia are so important, mutations in several IFT components lead to human disease. Thus, clarifying the molecular functions of the IFT proteins is a high priority in cilia biology. Live imaging in various species and cellular preparations has proven to be an important technique in both the discovery of IFT and the mechanisms by which it functions. Live imaging of Drosophila cilia, however, has not yet been reported. Here, we have visualized the movement of IFT in Drosophila cilia using time-lapse live imaging for the first time. We found that NOMPB-GFP (IFT88) moves according to distinct parameters depending on the ciliary segment. NOMPB-GFP moves at a similar speed in proximal and distal cilia toward the tip (${\sim}0.45{\mu}m/s$). As it returns to the ciliary base, however, NOMPB-GFP moves at ${\sim}0.12{\mu}m/s$ in distal cilia, accelerating to ${\sim}0.70{\mu}m/s$ in proximal cilia. Furthermore, while live imaging NOMPB-GFP, we observed one of the IFT proteins required for retrograde movement, Oseg4 (WDR35), is also required for anterograde movement in distal cilia. We anticipate our time-lapse live imaging analysis technique in Drosophila cilia will be a good starting point for a more sophisticated analysis of IFT and its molecular mechanisms.