136 research outputs found

    Experimental Study of the Injection System for CO2 Geologic Storage Demonstration

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    AbstractThe worldwide issue of greenhouse gas reduction has recently drawn great attention to carbon capture and storage (CCS). Almost CCS studies have been focused in the capture technology of carbon dioxide and the geological investigation for underground storage. The study of mechanical injection system for carbon dioxide has not implemented nearly. We are intended to develop a ground system for underground injection of carbon dioxide. In this study, we made lab-scale underground injection system and implemented injection simulation test experimentally. The 10,000 ton/year pilot plant for geological storage of carbon dioxide will be designed on the base of these test results. Major components of the lab-scale underground injection system include a pressure pump and an in-line heater to bring liquid carbon dioxide into its supercritical state. Test results assure that this system readily achieves the designed injection pressure and temperature, showing satisfactory control performance

    Bistable switching of a polymer-walled liquid crystal phase grating cell

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    We report bistable switching of a liquid crystal (LC) phase grating cell. Polymer walls are formed in an LC cell by phase separation of an LC mixture, induced by the spatial difference of the elastic energy and electric field intensity. Bistable switching of a polymer-walled liquid crystal phase grating cell could be realized by applying vertical and in-plane electric fields

    Metabolic engineering of a reduced-genome strain of Escherichia coli for L-threonine production

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    © 2009 Lee et al; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution Licens

    The use of gold nanoparticle aggregation for DNA computing and logic-based biomolecular detection

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    The use of DNA molecules as a physical computational material has attracted much interest, especially in the area of DNA computing. DNAs are also useful for logical control and analysis of biological systems if efficient visualization methods are available. Here we present a quick and simple visualization technique that displays the results of the DNA computing process based on a colorimetric change induced by gold nanoparticle aggregation, and we apply it to the logic-based detection of biomolecules. Our results demonstrate its effectiveness in both DNA-based logical computation and logic-based biomolecular detection.the Ministry of Commerce, Industry and Energy through the Molecular Evolutionary Computing (MEC) Project the Ministry of Education and Human Resources Development (MOEHRD) under the BK21-IT Program The ICT at Seoul National University provided research facilities a Korea Research Foundation Grant funded by the Korean Government (MOEHRD, Basic Research Promotion) (KRF-2006-351-C00045

    Pig-to-Nonhuman Primate (NHP) Naked Islet Xenotransplantation

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    Islet transplantation is an established therapy for selected type 1 diabetes (T1D) patients with severe hypoglycemic unawareness and glycemic liability despite of insulin treatment. However, the donor organ is limited. Porcine islets are the best alternative source to overcome this limitation, and pig-to-nonhuman primate (NHP) naked islet xenotransplantation studies are being performed worldwide. Several studies including our own have presented successful proof-of-concept results based on immunosuppression regimen including the anti-CD154 monoclonal antibody. Particularly, long-term control of diabetes by adult porcine islet transplantation has been demonstrated in five consecutive monkeys, and the longest survival was ~1000 days after transplantation. Currently, pig-to-NHP islet xenotransplantation based on clinically applicable immunosuppression regimen is being pursued. In this chapter, we will describe all the procedures of pig-to-NHP naked islet xenotransplantation: (1) the porcine islet isolation from designated pathogen-free (DPF) miniature pigs, (2) diabetes induction in monkeys, (3) transplantation procedure via the portal vein, (4) immune monitoring comprising humoral and cellular immunity after porcine islet transplantation, and finally (5) liver biopsy and subsequent immunohistochemical procedure in detail

    Tunable Polarization-Dependent Loss Element Based on Acoustooptic Mode Coupling in a Polarization-Maintaining Fiber

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    Abstract-We demonstrate a tunable polarization-dependent loss (PDL) element based on the polarization-dependent coupling of the fundamental core mode to the cladding mode by the flexural acoustic wave in a polarization-maintaining fiber with an elliptical stress member. The resonant wavelength of PDL is tunable by adjusting the frequency of radio-frequency (RF) signal applied to the acoustic transducer, while the magnitude of PDL is variable by the voltage of the same RF signal. Over the wavelength from 1530 to 1570 nm, the variable ranges of PDL for two linear orthogonal polarizations are 16 and 17 dB, respectively

    Different contribution of extent of myocardial injury to left ventricular systolic and diastolic function in early reperfused acute myocardial infarction

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    BACKGROUND: We sought to investigate the influence of the extent of myocardial injury on left ventricular (LV) systolic and diastolic function in patients after reperfused acute myocardial infarction (AMI). METHODS: Thirty-eight reperfused AMI patients underwent cardiac magnetic resonance (CMR) imaging after percutaneous coronary revascularization. The extent of myocardial edema and scarring were assessed by T2 weighted imaging and late gadolinium enhancement (LGE) imaging, respectively. Within a day of CMR, echocardiography was done. Using 2D speckle tracking analysis, LV longitudinal, circumferential strain, and twist were measured. RESULTS: Extent of LGE were significantly correlated with LV systolic functional indices such as ejection fraction (r��=��-0.57, p��<��0.001), regional wall motion score index (r��=��0.52, p��=��0.001), and global longitudinal strain (r��=��0.56, p��<��0.001). The diastolic functional indices significantly correlated with age (r��=��-0.64, p��<��0.001), LV twist (r��=��-0.39, p��=��0.02), average non-infarcted myocardial circumferential strain (r��=��-0.52, p��=��0.001), and LV end-diastolic wall stress index (r��=��-0.47, p��=��0.003 with e') but not or weakly with extent of LGE. In multivariate analysis, age and non-infarcted myocardial circumferential strain independently correlated with diastolic functional indices rather than extent of injury. CONCLUSIONS: In patients with timely reperfused AMI, not only extent of myocardial injury but also age and non-infarcted myocardial function were more significantly related to LV chamber diastolic function.ope

    Transmembrane topology and oligomeric nature of an astrocytic membrane protein, MLC1

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    MLC1 is a membrane protein mainly expressed in astrocytes, and genetic mutations lead to the development of a leukodystrophy, megalencephalic leukoencephalopathy with subcortical cysts disease. Currently, the biochemical properties of the MLC1 protein are largely unknown. In this study, we aimed to characterize the transmembrane (TM) topology and oligomeric nature of the MLC1 protein. Systematic immunofluorescence staining data revealed that the MLC1 protein has eight TM domains and that both the N- and C-terminus face the cytoplasm. We found that MLC1 can be purified as an oligomer and could form a trimeric complex in both detergent micelles and reconstituted proteoliposomes. Additionally, a single-molecule photobleaching experiment showed that MLC1 protein complexes could consist of three MLC1 monomers in the reconstituted proteoliposomes. These results can provide a basis for both the high-resolution structural determination and functional characterization of the MLC1 protein.1

    Pneumatosis Intestinalis with Pneumoperitoneum Mimicking Intestinal Perforation in a Patient with Myelodysplastic Syndrome after Hematopoietic Stem Cell Transplantation

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    Pneumatosis intestinalis (PI) is an uncommon disorder characterized by an accumulation of gas in the bowel wall, and has been associated with a variety of disorders and procedures. We describe a 35-year-old man who undertook hematopoietic stem cell transplantation due to myelodysplastic syndrome. An abdominal X-ray demonstrated extensive PI with pneumoperitoneum mimicking hollow organ perforation. However, the patient had no abdominal symptoms and there was no evidence of peritoneal inflammation. After two weeks of conservative management, including bowel rest and antibiotics, his pneumoperitoneum resolved spontaneously without any complications. Of the many factors that affect the gastrointestinal tract mucosal integrity, intramural pressure, and bacterial flora-produced intraluminal gas interact to produce PI. If the condition is accompanied by bowel ischemia, portomesenteric venous gas, metabolic acidosis, and abdominal sepsis, or if PI is severe in extent immediate surgical intervention is indicated. The described case supports that a mechanical rather than a bacterial etiology underlies the pathogenesis of PI
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