153 research outputs found

    Boundary Setting for Ecosystem Services by Factor Analysis: A Case Study in Seocheon, South Korea

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    Ecosystem service assessment maps are an important form of data, showing the flow and characteristics of ecosystem services. However, there has been a lack of research on the spatial boundaries of synergetic and trade-off relationships among different types of ecosystem services based on the microscopic characteristics of ecosystem maps. Therefore, the boundaries of ecosystems were identified in this study using factor analysis of indicators in ecosystem service maps. Ecosystems were mapped for each indicator in each cell, and then factor analysis was used to combine all indicators into one map. Analysis of Seocheon in central South Korea shows the boundaries of two ecosystem types: a mountainous region with abundant underground water and carbon stocks that lack rice paddies, and flatlands with high crop production and a lack of scenic views. The spatial types of ecosystems in which synergy and trade-offs occur were identified by indicator, and these can be used as evidentiary material for spatial planning in order to maximize the function of each ecosystem service

    Pneumatosis intestinalis after adult liver transplantation

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    Pneumatosis intestinalis is an uncommon disorder characterized by an accumulation of gas in the bowel wall. We described three cases undertaking liver transplantation. The patients developed diarrhea in three cases and high fever in two. An abdominal X-ray and computed tomography scan demonstrated extensive pneumatosis intestinalis in the colon with pneumoperitoneum mimicking hollow organ perforation. However, the patients had no abdominal symptoms and there was no evidence of peritonitis. The infection work-up was negative except one case with cytomegalovirus antigenemia. After one week of conservative management including bowel rest and antibiotic therapy, their pneumoperitoneum resolved spontaneously without any complication. Pneumatosis intestinalis should be considered as a differential diagnosis after adult liver transplantation with patients suffering from watery diarrhea and fever. Pneumoperitoneum, air-density in mesentery and retroperitoneum in patients with pneumatosis intestinalis without signs of peritonitis improved with conservative management, which included bowel rest and antibiotic therapy

    Cardiac tamponade caused by tuberculosis pericarditis in renal transplant recipients

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    A 50-year-old male, renal transplant recipient, was admitted with fever and chest discomfort. At admission, chest radiologic finding was negative and echocardiography showed minimal pericardial effusion. After 2 days of admission, chest pain worsened and blood pressure fell to 60/40 mmHg. Emergency echocardiography showed a large amount of pericardial effusion compressing the entire heart. Pericardiocentesis was performed immediately. Mycobacterium tuberculosis was isolated from pericardial fluid. Tuberculosis pericarditis should be considered as the cause of cardiac tamponade in renal transplant recipients, even with the absence of pericardial effusion in the initial study or suggestive history

    Withdrawal of Immunosuppression in Pediatric Liver Transplant Recipients in Korea

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    Purpose: We identified pediatric liver transplant recipients with successful withdrawal of immunosuppression who developed tolerance in Korea. Materials and Methods: Among 105 pediatric patients who received liver transplantation and were treated with tacrolimus-based immunosuppressive regimens, we selected five (4.8%) patients who had very low tacrolimus trough levels. Four of them were noncompliant with their medication and one was weaned off of immunosuppression due to life threatening posttransplant lymphoproliferative disorder. We reviewed the medical records with regard to the relationship of the donor-recipients, patient characteristics and prognosis, including liver histology, and compared our data with previous reports. Results: Four patients received the liver transplantation from a parent donor and one patient from a cadaver donor. A trial of withdrawal of the immunosuppressant was started a median of 45 months after transplantation (range, 14 months to 60 months), and the period of follow up after weaning from the immunosuppressant was a median of 32 months (range, 14 months to 82 months). None of the five patients had rejection episodes after withdrawal of the immunosuppression; they maintained normal graft function for longer than 3 years (median, 38 months; range, 4 to 53 months). The histological findings of two grafts 64 and 32 months after weaning-off of the medication showed no evidence of chronic rejection. Conclusion: The favorable markers for successful withdrawal of immunosuppression were 1) long-term (> 3 years) stable graft function, 2) no rejection for longer than 1 year after withdrawal of immunosuppression

    A SpÀtzle-processing enzyme required for toll signaling activation in Drosophila innate immunity

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    The Toll receptor was originally identified as an indispensable molecule for Drosophila embryonic development and subsequently as an essential component of innate immunity from insects to humans. Although in Drosophila the Easter protease processes the pro-SpÀtzle protein to generate the Toll ligand during development, the identification of the protease responsible for pro-SpÀtzle processing during the immune response has remained elusive for a decade. Here, we report a protease, called SpÀtzle-processing enzyme (SPE), required for Toll-dependent antimicrobial response. Flies with reduced SPE expression show no noticeable pro-SpÀtzle processing and become highly susceptible to microbial infection. Furthermore, activated SPE can rescue ventral and lateral development in embryos lacking Easter, showing the functional homology between SPE and Easter. These results imply that a single ligand/receptor-mediated signaling event can be utilized for different biological processes, such as immunity and development, by recruiting similar ligand-processing proteases with distinct activation modes

    Subchronic inhalation toxicity of gold nanoparticles

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    <p>Abstract</p> <p>Background</p> <p>Gold nanoparticles are widely used in consumer products, including cosmetics, food packaging, beverages, toothpaste, automobiles, and lubricants. With this increase in consumer products containing gold nanoparticles, the potential for worker exposure to gold nanoparticles will also increase. Only a few studies have produced data on the <it>in vivo </it>toxicology of gold nanoparticles, meaning that the absorption, distribution, metabolism, and excretion (ADME) of gold nanoparticles remain unclear.</p> <p>Results</p> <p>The toxicity of gold nanoparticles was studied in Sprague Dawley rats by inhalation. Seven-week-old rats, weighing approximately 200 g (males) and 145 g (females), were divided into 4 groups (10 rats in each group): fresh-air control, low-dose (2.36 × 10<sup>4 </sup>particle/cm<sup>3</sup>, 0.04 ÎŒg/m<sup>3</sup>), middle-dose (2.36 × 10<sup>5 </sup>particle/cm<sup>3</sup>, 0.38 ÎŒg/m<sup>3</sup>), and high-dose (1.85 × 10<sup>6 </sup>particle/cm<sup>3</sup>, 20.02 ÎŒg/m<sup>3</sup>). The animals were exposed to gold nanoparticles (average diameter 4-5 nm) for 6 hours/day, 5 days/week, for 90-days in a whole-body inhalation chamber. In addition to mortality and clinical observations, body weight, food consumption, and lung function were recorded weekly. At the end of the study, the rats were subjected to a full necropsy, blood samples were collected for hematology and clinical chemistry tests, and organ weights were measured. Cellular differential counts and cytotoxicity measurements, such as albumin, lactate dehydrogenase (LDH), and total protein were also monitored in a cellular bronchoalveolar lavage (BAL) fluid. Among lung function test measurements, tidal volume and minute volume showed a tendency to decrease comparing control and dose groups during the 90-days of exposure. Although no statistically significant differences were found in cellular differential counts, histopathologic examination showed minimal alveoli, an inflammatory infiltrate with a mixed cell type, and increased macrophages in the high-dose rats. Tissue distribution of gold nanoparticles showed a dose-dependent accumulation of gold in only lungs and kidneys with a gender-related difference in gold nanoparticles content in kidneys.</p> <p>Conclusions</p> <p>Lungs were the only organ in which there were dose-related changes in both male and female rats. Changes observed in lung histopathology and function in high-dose animals indicate that the highest concentration (20 ÎŒg/m<sup>3</sup>) is a LOAEL and the middle concentration (0.38 ÎŒg/m<sup>3</sup>) is a NOAEL for this study.</p

    Segmented tomographic evaluation of structural degradation of carbon support in proton exchange membrane fuel cells

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    The variation of the three-dimensional (3D) structure of the membrane electrode of a fuel cell during proton exchange cycling involves the corrosion/compaction of the carbon support. The increasing degradation of the carbon structure continuously reduces the electrocatalytic performance of proton exchange membrane fuel cells (PEM-FCs). This phenomenon can be explained by performing 3D tomographic analysis at the nanoscale. However, conventional tomographic approaches which present limited experimental feasibility, cannot perform such evaluation and have not provided sufficient structural information with statistical significance thus far. Therefore, a reliable methodology is required for the 3D geometrical evaluation of the carbon structure. Here, we propose a segmented tomographic approach which employs pore network analysis that enables the visualization of the geometrical parameters corresponding to the porous carbon structure at a high resolution. This approach can be utilized to evaluate the 3D structural degradation of the porous carbon structure after cycling in terms of local surface area, pore size distribution, and their 3D networking. These geometrical parameters of the carbon body were demonstrated to be substantially reduced owing to the cycling-induced degradation. This information enables a deeper understanding of the degradation phenomenon of carbon supports and can contribute to the development of stable PEM-FC electrodes. (C) 2022 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by ELSEVIER B.V. and Science Press

    High-performance and scalable metal-chalcogenide semiconductors and devices via chalco-gel routes

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    We report a general strategy for obtaining high-quality, large-areametal-chalcogenide semiconductor films from precursors combining chelated metal salts with chalcoureas or chalcoamides. Using conventional organic solvents, such precursors enable the expeditious formation of chalco-gels,which are easily transformed into the corresponding highperformance metal-chalcogenide thin films with large, uniform areas. Diverse metal chalcogenides and their alloys (MQx: M = Zn, Cd, In, Sb, Pb; Q = S, Se, Te) are successfully synthesized at relatively low processing temperatures (&amp;lt;400°C). The versatility of this scalable route is demonstrated by the fabrication of large-area thin-film transistors (TFTs), optoelectronic devices, and integrated circuits on a 4-inch Si wafer and 2.5-inch borosilicate glass substrates in ambient air using CdS, CdSe, and In2Se3 active layers. The CdSe TFTs exhibit a maximum field-effect mobility greater than 300 cm2 V-1 s-1 with an on/off current ratio of &amp;gt;107 and good operational stability (threshold voltage shift &amp;lt; 0.5 V at a positive gate bias stress of 10 ks). In addition,metal chalcogenide-based phototransistors with a photodetectivity of &amp;gt;1013 Jones and seven-stage ring oscillators operating at a speed of ∌2.6 MHz (propagation delay of &amp;lt; 27 ns per stage) are demonstrated. © 2018 The Authors.1
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