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Bibin Bintang Andriana,Tat Wei Tay,Ishii Maki,Mohammad Abdul Awal,Yoshiakira Kanai,Masamichi Kurohmaru,Yoshihiro Hayashi 대한수의학회 2004 Journal of Veterinary Science Vol.5 No.3
In this study, the effects of mono(2-ethylhexyl) phthalate (MEHP), one of metabolites of di(2-ethylhexyl) phthalate, on immature Shiba goat testes in vitro were examined. The testes of 2-month-old Shiba goats were cut into smaller pieces, and seeded in medium. At 1, 3, 6 and 9 hr after administration of MEHP at various concentrations (0,100 nmol · ml−1, 1 nmol · ml−1, and 1 × 10−3 nmol · ml−1, respectively), the specimens were obtained for light and transmission electron microscopic observations. As a result, at 1 hr after exposure to MEHP, the vacuolization and nuclear membrane rupture appeared in Sertoli cells. Such alterations tended to gradually increase in number in timeand dose-dependent manners. Moreover, by MEHP treatment, apoptotic spermatogenic cells (characterized with chromatin condensation, cytoplasm shrinkage without membrane rupture, still functioning cell organelles, and packed cell contents in membrane-bounded bodies), apoptotic Sertoli cells (characterized with nuclear membrane lysis, nuclear condensation), necrotic spermatogenic cells (characterized with swollen and ruptured mitochondria, plasma membrane lysis, spilt cell contents, and chromatin clumps), and necrotic Sertoli cells (characterized with marginated chromatins along the nuclear membrane, ruptured vesicles within the MNB, some swollen and ruptured cell organelles, e.g. mitochondria) could be identified. Conclusively, ultrastructurally the treatment with MEHP at low concentration tends to lead spermatogenic and Sertoli cells to apoptosis, whereas that at high concentration tends to lead spermatogenic and Sertoli cells to necrosis. Thus, the testicular tissue culture is advantageous for screening testicular toxicity of chemicals.
Patient-Specific Selective Tumor Heating for Liver Cancer Treatment with RF Hyperthermia
Bibin Prasad,Jung Kyung Kim 한국가시화정보학회 2015 한국가시화정보학회 학술발표대회 논문집 Vol.2015 No.12
Hyperthermia is a type of cancer treatment in which body tissue is exposed to higher temperatures to damage and kill cancer cells. Minimally invasive treatment of solid tumors, especially in the human organs, remains clinically challenging, despite a variety of treatment modalities are available. In the present study a non-invasive selective heating of tumor by sparing the normal cells was investigated with experimental and numerical approaches. A cylindrical tissuemimicking tumor phantom gel was prepared for the selectivity test and a patient-specific simulation on real human anatomy model, which was reconstructed and segmented from computed tomography (CT) image, was used to determine the thermal distribution in liver tumor during radiofrequency (RF) heating. An RF electrode at 13.56 MHz frequency was used as the heat source for the experiment and simulations were performed with the aid of the multiphysiscs simulation platform Sim4Life. Experimental results depict the selective heating of the tumor and the same was validated with that of simulations. A high temperature rise was achieved for the liver tumor from the patientspecific simulation which elucidated the high energy absorption of malignant tissue compared to the normal surrounding tissues and thereby regional heating of RF hyperthermia was demonstrated in a real human anatomy. The study also exhibits the effect of electrodes with different sizes and power modulation, which paves a way for effective treatment planning. The calculated thermal dose values depicts the damage of malignant tissues in the liver and no normal tissues were damaged during heating, which gives more realistic outcomes for clinical applications.
Properties and Performance of Eco-Friendly Hydro-Fluoro-Olefin (HFO) Refrigerant-R1234yf: Part I
Bibin B. S.,Gundabattini Edison 대한설비공학회 2021 International Journal Of Air-Conditioning and Refr Vol.29 No.3
The creation of new age refrigerants might be the answer to the issue of an Earth-wide rise in temperature. Hence, while choosing new refrigerants a careful process is required. The general effect of any refrigerant substance on global warming, energy efficiency, ozone depletion, cost-effectiveness, chemical stability, and safety ought to be assessed. This paper sums up the experimental and numerical investigations directed with the globally accepted R1234yf refrigerant. The paper’s principal points are to assess the capability of the hydro-fluoro-olefin (HFO) refrigerant mainly R1234yf utilized in the refrigeration system (vapor compression systems, domestic refrigeration system) and to explore its utilization as an eco-friendly refrigerant. In the vapor compression refrigeration system, the cooling capacity and coefficient of performance of R1234yf are found to be less, 9% and 11%, respectively compared to that of R134a. But the power consumption of the system with R1234yf increased between 1.6% and 6.7% when compared to R134a. This paper likewise assists with recognizing the gap in the past research works and explores the possibilities for additional works.
Prasad, Bibin,Kim, Subin,Cho, Woong,Kim, Suzy,Kim, Jung Kyung Elsevier 2018 Journal of thermal biology Vol.74 No.-
<P><B>Abstract</B></P> <P>Computational techniques can enhance personalized hyperthermia-treatment planning by calculating tissue energy absorption and temperature distribution. This study determined the effect of tumor properties on energy absorption, temperature mapping, and thermal dose distribution in mild radiofrequency hyperthermia using a mouse xenograft model. We used a capacitive-heating radiofrequency hyperthermia system with an operating frequency of 13.56 MHz for in vivo mouse experiments and performed simulations on a computed tomography mouse model. Additionally, we measured the dielectric properties of the tumors and considered temperature dependence for thermal properties, metabolic heat generation, and perfusion. Our results showed that dielectric property variations were more dominant than thermal properties and other parameters, and that the measured dielectric properties provided improved temperature-mapping results relative to the property values taken from previous study. Furthermore, consideration of temperature dependency in the bio heat-transfer model allowed elucidation of precise thermal-dose calculations. These results suggested that this method might contribute to effective thermoradiotherapy planning in clinics.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Effect of tumor property is investigated in radiofrequency hyperthermia. </LI> <LI> Dielectric property variations in tumor should be considered carefully in hyperthermia-treatment planning. </LI> <LI> Dielectric property variation and temperature dependency could improve the accuracy of thermal dose calculations. </LI> <LI> Our study contributes to effective thermoradiotherapy planning in clinics. </LI> </UL> </P>
Patient-specific simulation of highintensity focused ultrasound for head and neck cancer ablation
Abdul Mohizin,Bibin Prasad,Suzy Kim,김중경 대한기계학회 2023 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.37 No.4
This study used acoustic and biothermal simulations on reconstructed geometry of a patient with squamous cell carcinoma to investigate the feasibility of using high-intensity focused ultrasound (HIFU) for the thermal ablation of cancerous tumors in the oral cavity. Herein, the effect of HIFU treatment on a patient diagnosed with head and neck cancer was investigated using a commercialized finite-difference time-domain (FDTD) tool. The potential application of spherical and cylindrical transducer geometries with curvature radii ranging from 64 to 100 mm was investigated. The effect of frequency variation (from 0.2 to 1.5 MHz) on the thermal ablation characteristics of a spherical transducer was explored. The study also explored the influence of surrounding tissue structures on transducer motion by placing transducers in different positions. The spherical transducers were found to have focused acoustic energy deposition and their deposited acoustic energy was revealed to increase with frequency. Consequently, a higher ablation volume was realized due to the longer exposure time for the lower frequencies. Interference from bone structures can cause focal shifts or distortions in the deposited acoustic energy. However, no significant secondary hotspot regions were observed. Therefore, the investigated technique has the potential to be used for the successful noninvasive treatment of similar head and neck cancers.