• Journal of the Korean Institute of Telematics and Electronics
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• v.19 no.6
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• pp.33-40
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• 1982

Although ultrasonic CT is one of the useful techniques for tissue characterization, the reconstructed images, such as the velocity distribution and attenuation constant distribution, are degraded by reflection and refraction of ultrasonic beam. This paper studied the degradation effects on attenuation images using agar gel phantoms which were developed to evaluate ultrasonic CT. We found that the reconstructed attenuation constants at the center of the phantoms were less than the actual values by 0.6 dB/cm when phantom velocity differs by 25 m/s from surrounding saline. We also studied a correction method for refraction and phase cancellation effects, where the correction was made using the maximum value in the received subdata, as obtained by sub-arraying microprobes located at each sampling point. Using this method, we could obtain an improvement in the reconstructed image by the correction on the attenuation effect.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1994.04a
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• pp.292-292
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• 1994

Catecholamines acting through ${\beta}$-adrenergic receptors regulate a wide range of metabolic activities in mammalian tissue. Of the various receptors coupled to adenylate cyclase, the ${\beta}$-adrenergic receptors are the most extensively characterized and have been purified from both nonmammal ian and mammal inn sources. However, most studies of the molecular properties of ${\beta}$-adrenergic receptors have been confined to peripheral tissues. Less progress has been achieved in characterizing the brain ${\beta}$-adrenergic receptor The goal of the present study was, therefore, to purify and characterize the neurotransmitter receptor proteins. To achieve this goal, the following stepwise experiments were performed. At first, the membrane-bound ${\beta}$-adrenergic receptors were. solubi1ized from brain tissue. Secondly, conditions for affinity chromatography were determined to purify the solubilized receptors effectively. Finally, the large-scale purification was performed and the characteristics of the purified ${\beta}$-adrenergic receptor were examined.

• Proceedings of the KSME Conference
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• 2008.11a
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• pp.1692-1696
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• 2008

In this paper, we characterize the mechanical properties of PCL strand which is made by oscillating nozzle for tissue engineering scaffold. In order to increase the mechanical properties of the PCL strand, we designed an oscillating nozzle system for the 3D plotting system. First, we check the effect of the nozzle speed (3 to 8 mm/sec), frequency (0 or 300 Hz) and the oscillating amplitude (0 or 100 V) on the diameter of the PCL strand. Second, we observe the effect of the frequency (0, 100, 200 and 300 Hz) and the oscillating amplitude (0, 50 and 100 V) on the mechanical property of PCL strand. The mechanical properties and surface morphology of PCL strand made by oscillating nozzle are compared with the PCL strand made by normal nozzle using Nano-UTM and SEM.

• Mycobiology
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• v.39 no.3
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• pp.151-157
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• 2011

The endophytic fungal populations of different tissues of Taxus baccata grown at high altitudes in West Bengal, India were explored. These isolated fungal populations represented different genera, which were screened for taxol production using immunoassay technique. The culture AAT-TS-$4_1$ that produced taxol was identified as Gliocladium sp. based on its cultural, morphological characteristics, internal transcribed spacer, and 18S rRNA sequence analysis. Kinetics of taxol production as a function of culture growth were investigated.

• BMB Reports
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• v.41 no.12
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• pp.875-880
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• 2008

Mbu-3 is a novel mouse brain unigene that was identified by digital differential display. In this study, expression of the gene was chased through developmental stages and the protein product was identified in the brain. The cDNA sequence was 3,995-bp long and contained an ORF of 745 AA. Database searches revealed that the chicken SST273 gene containing LRR- and Ig-domain was an mbu-3 orthologue. Tissue specificity for the gene was examined in embryos and in brains at post-natal and adult stages. During the embryonic stages, mbu-3 was localized to the central nervous system in the brain and spinal cord. In the early post-natal stages, the gene was evenly expressed in the brain. However, with aging, expression was confined to specific regions, particularly the hippocampus. The protein was approximately 95 kDa as determined by Western blot analysis of brain extracts.

• Proceedings of the Korean Society of Toxicology Conference
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• 2003.10b
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• pp.122-122
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• 2003

Endometrial tissue is an interesting model for intrinsic and extrinsic factors, ie hormones and growth factors, involved in its normal pathologic development and its cyclic growth. The endometrial cells were isolated from endometrial tissue of the proliferative phase obtained by hysterectomy and separated stromal and epithelial cells.(omitted)

• Journal of Astronomy and Space Sciences
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• v.30 no.2
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• pp.107-112
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• 2013

Tissue equivalent proportional counter (TEPC) can measure the Linear Energy Transfer (LET) spectrum and calculate the equivalent dose for the complicated radiation field in space. In this paper, we developed and characterized a TEPC for radiation monitoring in International Space Station (ISS). The prototype TEPC which can simulate a 2 ${\mu}m$ of the site diameter for micro-dosimetry has been tested with a standard alpha source ($^{241}Am$, 5.5 MeV). Also, the calibration of the TEPC was performed by the $^{252}Cf$ neutron standard source in Korea Research Institute of Standards and Science (KRISS). The determined calibration factor was $k_f=3.59{\times}10^{-7}$ mSv/R.

• Proceedings of the Materials Research Society of Korea Conference
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• 2011.05a
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• pp.51.2-51.2
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• 2011

A novel electrospun nanofiber membrane was fabricated using combined poly (vinylphosphonic acid) (PVPA) and polyvinyl alcohol (PVA) intended for bone tissue engineering applications. PVPA is a proton-conducting polymer used as primer for bone implants and dental cements to prevent corrosion and brush abrasion. The phosphonate groups of PVPA have the ability to crosslink and attach itself to the hydroxyapatite surface facilitating faster integration of the biomaterial to the bone matrix. PVA was combined with PVPA to provide hydrophilicity, biocompatibility and improve its spinnability. To improve its mechanical strength, PVPA/PVA and neat PVA mixtures were combined to produce a multilayer scaffold. The physical and chemical properties of the of the fabricated matrix was investigated by SEM and TEM morphological analyses, tensile strength test, XRD, FT-IR spectra, swelling behavior and biodegradation rates, porosity and contact angle measurements. Biocompatibility was also examined in vitro by cytotoxicity and cell proliferation studies with MTT assay and cell adhesion behavior by SEM and confocal microscopy.

• Biomaterials and Biomechanics in Bioengineering
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• v.1 no.2
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• pp.63-71
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• 2014

This study aimed to develop a novel bioactive hybrid xerogel consisting of silk fibroin /$SiO_2-CaO-P_2O_5$ by sol-gel process at room temperature. Scanning electron microscopy (SEM), FT-IR Spectroscopy, pore measurement, mechanical property testing, in vitro bioactivity test and cytotoxicity assay were performed to characterize the xerogel for bone tissue engineering application. We have found that the xerogel possessed excellent pore structures and mechanical property. Once immersed in a simulated fluid (SBF), the xerogel exhibited profound bioactivity by inducing hydroxyapatite layers on its surfaces. The cell toxicity study also demonstrated that there was little toxic to MC3T3-E1 cells. These results indicate that silk fibroin /$SiO_2-CaO-P_2O_5$ hybrid xerogel potentially could be used as a bone tissue engineering material.

• Radiation Oncology Journal
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• v.37 no.2
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• pp.117-126
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• 2019

Purpose: The purpose of this study was to characterize and evaluate the clinical significance of volume changes of soft tissue sarcomas during radiation therapy (RT), prior to definitive surgical resection. Materials and Methods: Patients with extremity or pelvis soft tissue sarcomas treated at our institution from 2013 to 2016 with RT prior to resection were identified retrospectively. Tumor volumes were measured using cone-beam computed tomography obtained daily during RT. Linear regression evaluated the linearity of volume changes. Kruskal-Wallis tests, Mann-Whitney U tests, and linear regression evaluated predictors of volume change. Logistic and Cox regression evaluated volume change as a predictor of resection margin status, histologic treatment response, and tumor recurrence. Results: Thirty-three patients were evaluated. Twenty-nine tumors were high grade. Prior to RT, median tumor volume was 189 mL (range, 7.2 to 4,885 mL). Sixteen tumors demonstrated significant linear volume changes during RT. Of these, 5 tumors increased and 11 decreased in volume. Myxoid liposarcoma (n = 5, 15%) predicted decreasing tumor volume (p = 0.0002). Sequential chemoradiation (n = 4, 12%) predicted increasing tumor volume (p = 0.008) and corresponded to longer times from diagnosis to RT (p = 0.01). Resection margins were positive in three cases. Five patients experienced local recurrence, and 7 experienced distant recurrence, at median 8.9 and 6.9 months post-resection, respectively. Volume changes did not predict resection margin status, local recurrence, or distant recurrence. Conclusion: Volume changes of pelvis and extremity soft tissue sarcomas followed linear trends during RT. Volume changes reflected histologic subtype and treatment characteristics but did not predict margin status or recurrence after resection.