75 research outputs found

    Investigation Of Desirable Arrangement Of Thermoelectric Modules For The Radiant Cooling Panel

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    The thermoelectric module radiant cooling panel (TEM-RCP) is an alternative of the conventional hydraulic radiant cooling panels which has advantages of no refrigerant, no chemical reactions, and no moving parts. In addition, it has merits of easy control, fast response through direct heat absorption from TEM without water. However, there are few guidelines for designing the TEM-RCP and no study suggested how to arrange the thermoelectric modules for the radiant cooling panel. Therefore, this study aims to propose the desirable arrangement of thermoelectric modules for radiant cooling panel. To achieve this purpose, the design methods for TEM-RCP was developed based on the semi-black box model of TEM and 2D finite difference method. The mock up model of TEM-RCP was constructed to validate the proposed model and results. The TEM-RCP we constructed is composed of 7 TEMs, the aluminium plate, the heat sink attaching on the TEMs, duct and fan. The panel temperature is maintained in 16 at the cold side of TEM and rejected heat from hot side of TEM is removed by using fan. The design point we focused was the distribution of panel temperature according to the ASHRAE Handbook. Therefore, we investigated optimal array and distance between TEMs not to excess the maximum temperature difference 3 across a given grid. As a result, it is revealed that the triangular grid is the best grid for even temperature distribution of TEM-RCP and the optimal distance between TEMs is 0.2 m to 0.3 m according to the room condition and operation characteristics of TEM. The optimized results is verified using the mock up model of TEM-RCP in the laboratory experiments

    A Kinematic Perspective on the Formation Process of the Stellar Groups in the Rosette Nebula

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    peer reviewedStellar kinematics is a powerful tool for understanding the formation process of stellar associations. Here, we present a kinematic study of the young stellar population in the Rosette nebula using recent Gaia data and high-resolution spectra. We first isolate member candidates using the published mid-infrared photometric data and the list of X-ray sources. A total of 403 stars with similar parallaxes and proper motions are finally selected as members. The spatial distribution of the members shows that this star-forming region is highly substructured. The young open cluster NGC 2244 in the center of the nebula has a pattern of radial expansion and rotation. We discuss its implication on the cluster formation, e.g., monolithic cold collapse or hierarchical assembly. On the other hand, we also investigate three groups located around the border of the H II bubble. The western group seems to be spatially correlated with the adjacent gas structure, but their kinematics is not associated with that of the gas. The southern group does not show any systematic motion relative to NGC 2244. These two groups might be spontaneously formed in filaments of a turbulent cloud. The eastern group is spatially and kinematically associated with the gas pillar receding away from NGC 2244. This group might be formed by feedback from massive stars in NGC 2244. Our results suggest that the stellar population in the Rosette Nebula may form through three different processes: the expansion of stellar clusters, hierarchical star formation in turbulent clouds, and feedback-driven star formation

    Identifying a low-risk group for parametrial involvement in microscopic Stage IB1 cervical cancer using criteria from ongoing studies and a new MRI criterion

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    This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited.Abstract Background There are currently three ongoing studies on less radical surgery in cervical cancer: ConCerv, GOG-278, and SHAPE. The aim of this study was to evaluate the performance of the criteria used in ongoing studies retrospectively and suggest a new, simplified criterion in microscopic Stage IB1 cervical cancer. Methods A retrospective analysis was performed in 125 Stage IB1 cervical cancer patients who had no clinically visible lesions and were allotted based on microscopic findings after conization. All patients had magnetic resonance imaging (MRI) after conization and underwent type C2 radical hysterectomy. We suggested an MRI criterion for less radical surgery candidates as patients who had no demonstrable lesions on MRI. The rates of parametrial involvement (PMI) were estimated for patients that satisfied the inclusion criteria for ongoing studies and the MRI criterion. Results The rate of pathologic PMI was 5.6% (7/125) in the study population. ConCerv and GOG-278 identified 11 (8.8%) and 14 (11.2%) patients, respectively, as less radical surgery candidates, and there were no false negative cases. SHAPE and MRI criteria identified 78 (62.4%) and 74 (59.2%) patients, respectively, as less radical surgery candidates; 67 patients were identified as less radical surgery candidates by both sets of criteria. Of these 67 patients, only one had pathologic PMI with tumor emboli. Conclusions This study suggests that the criteria used in three ongoing studies and a new, simplified criterion using MRI can identify candidates for less radical surgery with acceptable false negativity in microscopic Stage IB1 disease

    A Case of Non-Functioning Huge Adrenocortical Carcinoma Extending Into Inferior Vena Cava and Right Atrium

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    Primary adrenocortical carcinoma (ACC) is a rare tumor and its usual sites of metastasis are the lung (71%), lymph node (68%), liver (42%), and bone (26%). However, intracaval invasion extending into the right atrium is very rare and spontaneous regression of tumor burden in adrenal carcinoma is also rare. We report a case of ACC with direct invasion of the inferior vena cava and right atrium. A 34-yr-old male patient presented with progressive dyspnea, weight loss, and poor oral intake over 3 months. Non-functioning ACC with direct invasion of the inferior vena cava and right atrium was confirmed by imaging, pathologic, and hormonal study. Chemo-radio-therapy was attempted. However, tumor burden was not changed, but rather toxic hepatitis and thrombocytopenia were developed. His subjective symptoms and general conditions were improved after 1 month of conservative management and the patient was discharged. During clinical follow-up, this tumor showed spontaneous regression

    Lycopene Inhibits Reactive Oxygen Species-Mediated NF-κB Signaling and Induces Apoptosis in Pancreatic Cancer Cells

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    Generation of excess quantities of reactive oxygen species (ROS) caused by mitochondrial dysfunction facilitates rapid growth of pancreatic cancer cells. Elevated ROS levels in cancer cells cause an anti-apoptotic effect by activating survival signaling pathways, such as NF-κB and its target gene expression. Lycopene, a carotenoid found in tomatoes and a potent antioxidant, displays a protective effect against pancreatic cancer. The present study was designed to determine if lycopene induces apoptosis of pancreatic cancer PANC-1 cells by decreasing intracellular and mitochondrial ROS levels, and consequently suppressing NF-κB activation and expression of NF-κB target genes including cIAP1, cIAP2, and survivin. The results show that the lycopene decreased intracellular and mitochondrial ROS levels, mitochondrial function (determined by the mitochondrial membrane potential and oxygen consumption rate), NF-κB activity, and expression of NF-κB-dependent survival genes in PANC-1 cells. Lycopene reduced cell viability with increases in active caspase-3 and the Bax to Bcl-2 ratio in PANC-1 cells. These findings suggest that supplementation of lycopene could potentially reduce the incidence of pancreatic cancer

    Empirical Analysis for the Heat Exchange Effectiveness of a Thermoelectric Liquid Cooling and Heating Unit

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    This study aims to estimate the performance of thermoelectric module (TEM) heat pump for simultaneous liquid cooling and heating and propose empirical models for predicting the heat exchange effectiveness. The experiments were conducted to investigate and collect the performance data of TEM heat pump where the working fluid was water. A total of 57 sets of experimental data were statistically analyzed to estimate the effects of each independent variable on the heat exchange effectiveness using analysis of variance (ANOVA). To develop the empirical model, the six design parameters were measured: the number of transfer units (NTU) of the heat exchangers (i.e., water blocks), the inlet water temperatures and temperatures of water blocks at the cold and hot sides of the TEM. As a result, two polynomial equations predicting heat exchange effectiveness at the cold and hot sides of the TEM heat pump were derived as a function of the six selected design parameters. Also, the proposed models and theoretical model of conventional condenser and evaporator for heat exchange effectiveness were compared with the additional measurement data to validate the reliability of the proposed models. Consequently, two conclusions have been made: (1) the possibility of using the TEM heat pump for simultaneous cooling and heating was examined with the maximum temperature difference of 30 °C between cold and hot side of TEM, and (2) it is revealed that TEM heat pump has difference with the conventional evaporator and condenser from the comparison results between the proposed models and theoretical model due to the heat conduction and Joule effect in TEM
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