840 research outputs found

    Engineering of Klebsiella oxytoca capable of simultaneous utilization of multiple sugars for the production of 2, 3- Butanediol

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    From various biomasses such as lignocellulose and microalgae, many kinds of monosaccharides including glucose, galactose, xylose, mannose, ribose, rhamnose, and fucose can be obtained. Among them, galactose and xylose are the major carbon sources except for glucose in nature, and both sugars can serve as additive for the production of desired chemicals in the glucose-based fermentation. However, in many microorganisms, the glucose hampers utilization of galactose and xylose until depletion of glucose owing to Carbon Catabolite Repression (CCR) mechanism, which has been a big hurdle for the development of bioprocess utilizing multiple carbon sugars. Here, we developed Klebsiella oxytoca capable of simultaneous utilization of three sugars including glucose, galactose and xylose for the fermentative production of 2,3-butanediol which is a vital platform compound, used as liquid fuel and chemical raw material. To eliminate CCR and utilize multiple sugars, the phosphotransferase system (PTS) which is the main transporter for glucose was disrupted, in which cells could uptake glucose through alternative pathway and the transport system for other sugars could be activated. To verify the removal of CCR by disruption of PTS, the engineered strain was cultivated with two or three sugars and, we found that the simultaneous consumption of galactose and xylose was achieved although glucose consumption rate was decreased a little. At the time point of complete consumption of glucose, most galactose was also consumed and, about 30 % of xylose was consumed before glucose depletion. Under the simultaneous utilization of galactose and xylose along with glucose, 2,3-butaneidol was also successfully produced as high as 0.3 g/g, which yield is similar as that in cultivation with glucose as a sole carbon source. To the best of our knowledge, this is the first example of CCR elimination in K. oxytoca and, we think that our strategy sheds new light on an engineering of K. oxytoca for commercial exploitation of biomass to produce value-added products

    Peculiar Mammographic and Ultrasonographic Findings of a Retained Silastic Drain in the Breast

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    Foreign bodies, such as surgical sponges or drains, are sometimes retained after surgical procedures.1 Retention of a drain in the breast tissue postoperatively is an unusual complication. This report describes two cases of characteristic sonographic findings related to retained silastic drains following breast surgery

    Large-Scale Plasma Polymer Coating on Heat Exchanger Fins for Improving the Wettability

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    This research presents the results of the recently developed large-scale hydrophilic polymer coating by plasma polymerization, optimum plasma zone (OPZ) process. The excellent hydrophilicity of heat exchanger fin surface could give good effects to efficient drainage of condensate water as well as heat transfer performance. The hydrophilicity of layer treated by large-scale OPZ system is excellent irrespective of line speed from 0.6 m/min to 2.4 m/min. The good lateral uniformity of the hydrophilicity could be acquired in large scale OPZ treatment. The application of OPZ technique to the heat exchanger could enhance the efficiency of heat transfer, resulting from decrease of pressure drop. Due to long-term durability of hydrophilicity, the heat transfer performance improved by OPZ process cannot be deteriorated with operation cycle

    Possible link between Arctic Sea ice and January PM10 concentrations in South Korea

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    In this study, we investigated the possible teleconnection between PM10 concentrations in South Korea and Arctic Sea ice concentrations at inter-annual time scales using observed PM10 data from South Korea, NCEP R2 data, and NOAA Sea Ice Concentration (SIC) data from 2001 to 2018. From the empirical orthogonal function (EOF) analysis, we found that the first mode (TC1) was a large-scale mode for PM10 in South Korea and explained about 27.4% of the total variability. Interestingly, the TC1 is more dominantly influenced by the horizontal ventilation effect than the vertical atmospheric stability effect. The pollution potential index (PPI), which is defined by the weighted average of the two ventilation effects, is highly correlated with the TC1 of PM10 at a correlation coefficient of 0.75, indicating that the PPI is a good measure for PM10 in South Korea at inter-annual time scales. Regression maps show that the decrease of SIC over the Barents Sea is significantly correlated with weakening of high pressure over the Ural mountain range region, the anomalous high pressure at 500 hPa over the Korean peninsula, and the weakening of the Siberian High and Aleutian low. Moreover, these patterns are similar to the correlation pattern with the PPI, suggesting that the variability of SIC over the Barents Sea may play an important role in modulating the variability of PM10 in South Korea through teleconnection from the Barents Sea to the Korean peninsula via Eurasia

    Dieulafoy's Lesion of Jejunum: Presenting Small Bowel Mass and Stricture

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    Dieulafoy's lesion is an uncommon cause of gastrointestinal bleeding. Hemorrhage occurs through mucosal erosion from an abnormally dilated submucosal artery. Although Dieulafoy's lesion is usually located in the stomach, it may occur anywhere in the gastrointestinal tract. We report here on a case of jejunal Dieulafoy's lesion presenting as a mass and short segment stricture on CT and enteroclysis

    The Safety and Efficiency of the Ultrasound-guided Large Needle Core Biopsy of Axilla Lymph Nodes

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    PURPOSE: To evaluate the safety and efficiency of the Ultrasound (US)-guided large needle core biopsy of axilla lymph nodes. MATERIALS AND METHODS: From March 2004 to September 2005, 31 patients underwent the US-guided core biopsy for axilla lymph nodes. Twenty five lesions out of 31 were detected during breast US, and 6 of 31 cases were palpable. Lymph nodes were classified based on their shape and cortical morphology. The core biopsy of axilla lymph nodes was performed on suspicious lymph nodes found during breast ultrasonography to find out whether the patients had a history of breast cancer or not. Among the 31 patients, 16 patients were associated with breast cancer. The lesion sizes varied from 0.6 cm to 3.3 cm (mean=1.59+/-0.76 cm). US-guided core biopsies were performed with 14 G needles with an automated biopsy gun. Total 3 or 5 specimens were obtained. RESULTS: Among the 31 cases of axilla lymph nodes core biopsies, 11 cases showed malignant pathology. Seven out of 11 cases were metastatic lymph nodes from breast cancer; 2 cases were from primary unknown and 2 cases from lymphomas. On the other hand, 20 histopathologic results of axilla lesions were benign: subacute necrotizing lymphadenitis (n=2), dermatopathic lymphadenitis (n=1), reactive hyperplasia (n=10) and free of carcinoma (n=7). CONCLUSION: The US-guided large needle core biopsy of axilla lesions is safe and effective for the pathological evaluation. The core biopsy is believed to be easy to perform if suspicious lymph nodes or mass lesions are found in the axillaope

    Permanent Hydrophilic Surface Formation by Ion Assisted Reaction

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    Since totally wettable hydrophilic polymer surfaces from hydrophobic polymers (PMMA, PTFE, PET and PC) have been demonstrated for the first time at Materials Research Society meeting, 1995 Fall meeting, Boston, the application of ion assisted reaction (IAR), in which energetic ions (0.5~1.5 keV) are irradiated on materials with blowing reactive gases near the irradiating surfaces, has been extended to various polymer, ceramic and metal for creating permanent hydrophilic surfaces. The surface energy was measured by Youngs equation and the highest energy, Es, of 60~70 mN/m, which is similar to surface energy of water (Es of H2O : 72 mN/m) is obtained by controlling ion dose, energy, and amount of blown gas. The higher surface energy of materials possesses the more wettable surface, and relation between wettability and adhesion has been discussed. The remarkable result is the strong adhesion of inert nonattachable material such as Pt on the modified surface. The improvements of adhesions, wettability and surface energy are mainly due to polar force and hydrophilic functional groups such as C=O, (C=O)-O, C-O, etc. on the modified surface without surface damage by surface analyses. Advantages of the method are (1) high reproducibility, (2) simplicity, (3) changing ability of wettability degree, and (4) easy connection to conventional semiconductor process line. Improvements of efficiencies by changing heat transfer coefficients have been presented for the compact heat exchanger system

    Develop to Term Rat Oocytes Injected with Heat-Dried Sperm Heads

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    This study investigated the development of rat oocytes in vitro and in vivo following intracytoplasmic injection of heads from spermatozoa heat-dried at 50ยฐC for 8 h and stored at 4ยฐC in different gas phases. Sperm membrane and chromosome are damaged by the process of heat-drying. Oocyte activation and cleavage of oocytes were worse in oocytes injected with spermatozoa heat-dried and stored for 1 week than unheated, fresh spermatozoa, but in heat-dried spermatozoa, there were no differences in these abilities of oocytes between the samples stored in nitrogen gas and in air. The oocytes injected with heat-dried spermatozoa stored for 1 week could develop to the morula and blastocyst stages without difference between the samples stored in nitrogen gas and in air after artificial stimulation. Cleavage of oocytes and development of cleaved embryos were higher when heat-dried spermatozoa were stored for 3 and 6 months in nitrogen gas than in air. However, the ability of injected oocytes to develop to the morula and blastocyst stages was not inhibited even when heat-dried spermatozoa stored in both atmosphere conditions for as long as 6 months were used. When 2-cell embryos derived from oocytes injected with heads from spermatozoa heat-dried and stored for 1 week and 1 month were transferred, each 1 of 4 recipients was conceived, and the conceived recipients delivered 1 live young each. These results demonstrate that rat oocytes can be fertilized with heat-dried spermatozoa and that the fertilized oocytes can develop to term
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