• Wind and Structures
• /
• v.34 no.2
• /
• pp.231-257
• /
• 2022

Transmission lines systems are important components of the electrical power infrastructure. However, these systems are vulnerable to damage from high wind events such as hurricanes. This study presents the results from a 1:50 scale aeroelastic model of a multi-span transmission lines system subjected to simulated hurricane winds. The transmission lines system considered in this study consists of three lattice towers, four spans of conductors and two end-frames. The aeroelastic tests were conducted at the NSF NHERI Wall of Wind Experimental Facility (WOW EF) at the Florida International University (FIU). A horizontal distortion scaling technique was used in order to fit the entire model on the WOW turntable. The system was tested at various wind speeds ranging from 35 m/s to 78 m/s (equivalent full-scale speeds) for varying wind directions. A system identification (SID) technique was used to evaluate experimental-based along-wind aerodynamic damping coefficients and compare with their theoretical counterparts. Comparisons were done for two aeroelastic models: (i) a self-supported lattice tower, and (ii) a multi-span transmission lines system. A buffeting analysis was conducted to estimate the response of the conductors and compare it to measured experimental values. The responses of the single lattice tower and the multi-span transmission lines system were compared. The coupling effects seem to drastically change the aerodynamic damping of the system, compared to the single lattice tower case. The estimation of the drag forces on the conductors are in good agreement with their experimental counterparts. The incorporation of the change in turbulence intensity along the height of the towers appears to better estimate the response of the transmission tower, in comparison with previous methods which assumed constant turbulence intensity. Dynamic amplification factors and gust effect factors were computed, and comparisons were made with code specific values. The resonance contribution is shown to reach a maximum of 18% and 30% of the peak response of the stand-alone tower and entire system, respectively.

• Journal of Microbiology and Biotechnology
• /
• v.33 no.6
• /
• pp.797-805
• /
• 2023

Species belonging to the Vernonia (Asteraceae), the largest genus in the tribe Vernonieae (consisting of about 1,000 species), are widely used in food and medicine. These plants are rich sources of bioactive sesquiterpene lactones and steroid saponins, likely including many as yet undiscovered chemical components. A phytochemical investigation resulted in the separation of three new stigmastane-type steroidal saponins (1 - 3), designated as vernogratiosides A-C, from whole plants of V. gratiosa. Their structures were elucidated based on infrared spectroscopy (IR), one-dimensional (1D) and two-dimensional nuclear magnetic resonance (2D NMR), high-resolution electrospray ionization mass spectrometry (HR-ESI-MS), and electronic circular dichroism analyses (ECD), as well as chemical reactivity. Molecular docking analysis of representative saponins with α-glucosidase inhibitory activity was performed. Additionally, the intended substances were tested for their ability to inhibit α-glucosidase activity in a laboratory setting. The results suggested that stigmastane-type steroidal saponins from V. gratiosa are promising candidate antidiabetic agents.

• Journal of the Korean Society of Radiology
• /
• v.84 no.3
• /
• pp.550-564
• /
• 2023

MRI is currently the imaging modality of choice to evaluate rectal cancer after neoadjuvant treatment. The purposes of restaging MRI are to assess the resectability of rectal cancer and to decide whether organ preservation strategies can be applied in patients with a complete clinical response. This review article indicates the key MRI features needed to evaluate rectal cancer after neoadjuvant treatment using a systematic approach. Assessment of primary tumor response including MRI findings to predict a complete response is discussed. Additionally, MRI evaluation of the relationship between the primary tumor and adjacent structures, lymph node response, extramural venous invasion, and tumor deposits after neoadjuvant treatment is presented. Knowledge of these imaging features and their clinical relevance may help radiologists provide an accurate and clinically valuable interpretation of restaging rectal MRI.

• Annals of Hepato-Biliary-Pancreatic Surgery
• /
• v.26 no.3
• /
• pp.285-288
• /
• 2022

Three-dimensional (3D) modeling of the liver can be especially useful for both the surgeon and patient to understand the actual location of the tumor and planning the resection plane. Virtual reality (VR) can enhance the understanding of 3D structures and create an environment where the user can focus on contents provided. In the present study, a VR platform was developed using Unreal Engine 4 software (Epic Games, Potomac, MD, USA). Patient's liver based on magnetic resonance image was imported as a 3D model that could distinguish liver parenchyma, vascular structure, and cancer. Preoperative education videos for patients were developed. They could be viewed inside the VR platform. To evaluate the usefulness of VR education program for patients undergoing liver resection for hepatocellular carcinoma, a randomized clinical trial evaluating the knowledge and anxiety of the patient was designed. The case presented in this report was the first experience of performing the VR education program and examining the knowledge and anxiety using questionnaires. When the knowledge score increased, the anxiety score also increased after the education program. Based on findings of this pilot case study, the timing and place where the questionnaire will be answered can be modified for formal initiation of the randomized controlled study to examine the usefulness of VR in patient education.

• Korean Journal of Acupuncture
• /
• v.41 no.3
• /
• pp.68-78
• /
• 2024

Objectives : Acupuncture is recognized as a significant therapeutic method in traditional medicine, underscoring the importance of precise understanding of acupoint locations and anatomical structures. The aim of this study is to investigate trends in anatomical studies of acupoint using imaging devices in China through literature search. Methods : This study utilized Chinese databases CNKI, WANFANG, and WEIPU to search for articles. The analysis focused on the publication status of articles by year, types of imaging devices, research subjects and methods, and criteria for acupoint locations. Results : A total of 15 articles were selected in this study. The first article was published in 1996. Articles were published at a rate of less than one per year until 2020, but rapidly increased to three and six in 2021 and beyond. Studies using ultrasonography were the most prevalent, followed by Magnetic Resonance Imaging(MRI) and Computed Tomography(CT) scans. There were eight studies conducted on healthy volunteers, six studies observing both healthy volunteers and cadavers, and also studies involving patients with specific medical conditions. Various criteria were employed to determine acupoint locations, including the WHO standard, national administration of traditional Chinese medicine nomenclature and location of acupoints, as well as references from literature. Conclusions : In China, researches are actively being conducted to observe the anatomical structure of acupoints using various imaging devices. Recent trends indicate an increase in studies utilizing ultrasound and there is a growing focus on exploring the locations that elicit the sensation of "obtaining qi" rather than just the anatomical locations of acupoints. Through this study, it is hoped that the appropriate utilization of imaging devices will lead to various studies aimed at elucidating the characteristics of the anatomical tissues actually stimulated during acupuncture, thereby increasing the safety and efficacy of acupuncture treatments.

• The Journal of Korean Physical Therapy
• /
• v.18 no.6
• /
• pp.1-11
• /
• 2006

Purpose: This study compared the effects of non-cold and cold conditions on the viscoelastic properties of tendon structures in vivo. Methods: Seven male subjects perfomed plantar flesion exercise with maximal isokinetic voluntary contraction, which consisted of muscle contraction for 6 see and relaxation for 60 secs, 10 times for 1 set, Totally 10 sets were repeated. Before and after each task, the elongation of the tendon and aponeurosis of the medial gastrocnemius muscle (MG) was directly measured by ultrasonography. (The relationship between the estimated tendon force and tendon elongation.) Tendon cross-sectional area and ankle joint moment arm were obtained from magnetic resonance imaging (MRI). The tendon force was calculated from the joint moments and the tendon moment arm and stress was obtained by dividing force by cross-sectional areas (CSA). The strain was measured from the displacements normalized to tendon length. Results: After cooling, the tendon force was larger in cold than non-cold. The value of the tendon stiffness of MVC were significantly higher under the cold condition than under the non-cold condition. The maximal strain and stress of $7.4{\pm}0.7%$ and $36.4{\pm}1.8$ MPa in non-cold and $7.8{\pm}8.5%,\;31.8{\pm}1.1$ MPa in cold (P<0.05). Conclusion: This study shows for the first time that the muscle endurance in cooling increases the stiffness and Young's modulus of human tendons. The improvement in muscle endurance with cooling was directly related to muscle and tendon.

• BMB Reports
• /
• v.34 no.1
• /
• pp.73-79
• /
• 2001

Transcriptional activation domains are known to be inherently "unstructured" with no tertiary structure. A recent NMR study, however, has shown that the transactivation domain in human p53 is populated with an amphipathic helix and two nascent turns. This suggests that the presence of such local secondary structures within the overall "unstructured" structural framework is a general feature of acidic transactivation domains. These pre-existing local structures in p53, formed selectively by positional conserved hydrophobic residues that are known to be critical for transcriptional activity, thus appear to constitute the specific structural motifs that regulate recognition of the p53 transactivation domain by target proteins. Here, we report the results of a NMR structural comparison between the native human p53 transactivation domain and an inactive mutant (22L,23W$\rightarrow$22R,23S). Results show that the mutant has an identical overall structural topology as the native protein, to the extent that the amphipathic helix formed by the residues 18T 26L within the native p53 transactivating domain is preserved in the double mutant. Therefore, the lack of transcriptional activity in the double mutant should be ascribed to the disruption of the essential hydrophobic contacts between the p53 transactivation domain and target proteins due to the (22L,23W$\rightarrow$22R,23S) mutation.

• Progress in Medical Physics
• /
• v.9 no.1
• /
• pp.47-53
• /
• 1998

Nuclear Medicine Images have comparatively poor spatial resolution, making it difficult to relate the functional information which they contain to precise anatomical structures. Anatomical structures useful in the interpretation of SPECT /PET Images were radiolabelled. PET/SPECT Images Provide functional information, whereas MRI mainly demonstrate morphology and anatomical. Fusion or Image Registration improves the information obtained by correlating images from various modalities. Brain Scan were studied on one or more occations using MRI and SPECT. The data were aligned using a point pair methods and surface matching. SPECT and MR Images was tested using a three dimensional water fillable Hoffman Brain Phantom with small marker and PET and MR Image was tested using a patient data. Registration of SPECT and MR Images is feasible and allows more accurate anatomic assessment of sites of abnormal uptake in radiolabeled studies. Point based registration was accurate and easily implemented three dimensional registration of multimodality data set for fusion of clinical anatomic and functional imaging modalities. Accuracy of a surface matching algorithm and homologous feature pair matching for three dimensional image registration of Single Photon Emission Computed Tomography Emission Computed Tomography (SPECT), Positron Emission Tomography (PET) and Magnetic Resonance Images(MRD was tested using a three dimensional water fill able brain phantom and Patients data. Transformation parameter for translation and scaling were determined by homologous feature point pair to match each SPECT and PET scan with MR images.

• Journal of the Korea Concrete Institute
• /
• v.18 no.4 s.94
• /
• pp.489-496
• /
• 2006

Graft copolymerized polycarboxylate(PC)-type superplasticizers which have carboxylic acid with $\pi$ bond among the molecular structure and polyethyleneglycol methyl ether methacrylate(PMEM) were synthesized by free radical reaction. To investigate their chemical structures and molecular weights, PCs were analyzed by FT-IR(fourier transform spectrometer), C-NMR(nuclear magnetic resonance spectrometer) and GPC(gel permeation chromatograpy). When types of carboxylic acids(methacrylic acid, acrylic acid, maleic anhydride, and itaconic acid) and molar ratios of carboxylic acid/PMEM) were varied, adsorptive and fluid characteristics in cement paste were discussed. As the molar ratio of carboxylic acid/PMEM) was higher, amount adsorbed on the cement particles and the fluidity of cement paste by mini-slump spread testing method were increased. When main chain of PC was methacrylic acid, a larger amount was adsorbed on the cement particles. PCs with acrylic acid as main chain showed higher dispersing power. However, it was confirmed that PCs with dicarboxylic acids(maleic anhydride, itaconic acid) didn't have good adsorption and dispersibility.

• Korean Journal of Optics and Photonics
• /
• v.34 no.6
• /
• pp.241-247
• /
• 2023

We examine the spectral characteristics of laser-induced periodic surface structures (LIPSSs) formed on an amorphous silicon film irradiated by a 355-nm nanosecond laser. A Gaussian beam with a diameter of 196 ㎛ is used to perform a two-dimensional raster scan. The laser's pulse number is varied from 190 to 280, and its intensity is adjusted within 100-130 mJ/cm². LIPSSs with a periodicity of approximately 330 nm form on the surface of the Si film, aligned perpendicular to the laser's polarization. Transmission spectra of the samples show dips around 700 nm for transverse electric polarization and around 500 nm for transverse magnetic polarization. The features are investigated with a one-dimensional-grating model using a rigorous coupled-wave analysis. Simulations confirm that the observed dips are due to the resonant modes, depending on the polarization.