726 research outputs found

    MRI Visualization of Whole Brain Macro- and Microvascular Remodeling in a Rat Model of Ischemic Stroke: A Pilot Study

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    Using superparamagnetic iron oxide nanoparticles (SPION) as a single contrast agent, we investigated dual contrast cerebrovascular magnetic resonance imaging (MRI) for simultaneously monitoring macro- and microvasculature and their association with ischemic edema status (via apparent diffusion coefficient [ADC]) in transient middle cerebral artery occlusion (tMCAO) rat models. High-resolution T1-contrast based ultra-short echo time MR angiography (UTE-MRA) visualized size remodeling of pial arteries and veins whose mutual association with cortical ischemic edema status is rarely reported. ??R2?????R2*-MRI-derived vessel size index (VSI) and density indices (Q and MVD) mapped morphological changes of microvessels occurring in subcortical ischemic edema lesions. In cortical ischemic edema lesions, significantly dilated pial veins (p???=???0.0051) and thinned pial arteries (p???=???0.0096) of ipsilateral brains compared to those of contralateral brains were observed from UTE-MRAs. In subcortical regions, ischemic edema lesions had a significantly decreased Q and MVD values (p???<???0.001), as well as increased VSI values (p???<???0.001) than normal subcortical tissues in contralateral brains. This pilot study suggests that MR-based morphological vessel changes, including but not limited to venous blood vessels, are directly related to corresponding tissue edema status in ischemic stroke rat models

    Three-dimensional flow phenomena in a wire-wrapped 37-pin fuel bundle for SFR

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    AbstractThree-dimensional flow phenomena in a wire-wrapped 37-pin fuel assembly mock-up of a Japanese loop-type sodium-cooled fast reactor, Monju, were investigated with a numerical analysis using a general-purpose commercial computational fluid dynamics code, CFX. Complicated and vortical flow phenomena in the wire-wrapped 37-pin fuel assembly were captured by a Reynolds-averaged Navier–Stokes flow simulation using a shear stress transport turbulence model. The main purpose of the current study is to understand the three-dimensional complex flow phenomena in a wire-wrapped fuel assembly to support the license issue for the core design. Computational fluid dynamics results show good agreement with friction factor correlation models. The secondary flow in the corner and edge subchannels is much stronger than that in an interior subchannel. The axial velocity averaged in the corner and edge subchannels is higher than that averaged in the interior subchannels. Three-dimensional multiscale vortex structures start to be formed by an interaction between secondary flows around each wire-wrapped pin. Behavior of the large-scale vortex structures in the corner and edge subchannels is closely related to the relative position between the hexagonal duct wall and the helically wrapped wire spacer. The small-scale vortex is axially developed in the interior subchannels. Furthermore, a driving force on each wire spacer surface is closely related to the relative position between the hexagonal duct wall and the wire spacer

    Glucose repression of the Escherichia coli sdhCDAB operon, revisited: regulation by the CRP·cAMP complex

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    Expression of the Escherichia coli sdhCDAB operon encoding the succinate dehydrogenase complex is regulated in response to growth conditions, such as anaerobiosis and carbon sources. An anaerobic repression of sdhCDAB is known to be mediated by the ArcB/A two-component system and the global Fnr anaerobic regulator. While the cAMP receptor protein (CRP) and Cra (formerly FruR) are known as key mediators of catabolite repression, they have been excluded from the glucose repression of the sdhCDAB operon. Although the glucose repression of sdhCDAB was reported to involve a mechanism dependent on the ptsG expression, the molecular mechanism underlying the glucose repression has never been clarified. In this study, we re-examined the mechanism of the sdhCDAB repression by glucose and found that CRP directly regulates expression of the sdhCDAB operon and that the glucose repression of this operon occurs in a cAMP-dependent manner. The levels of phosphorylated enzyme IIA(Glc) and intracellular cAMP on various carbon sources were proportional to the expression levels of sdhC-lacZ. Disruption of crp or cya completely abolished the glucose repression of sdhC-lacZ expression. Together with data showing correlation between the intracellular cAMP concentrations and the sdhC-lacZ expression levels in several mutants and wild type, in vitro transcription assays suggest that the decrease in the CRP·cAMP level in the presence of glucose is the major determinant of the glucose repression of the sdhCDAB operon

    Effect of the Ratio of Raw Material Components on the Physico-chemical Characteristics of Emulsion-type Pork Sausages

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    This study was conducted to investigate the effects of raw material ratio on the physicochemical characteristics of emulsion-type pork sausages. Experiment design was divided into 12 treatments, based on protein level (P), fat level (3P, 3.5P, and 4P), and water level (4P+10, 4P+15, 4P+20, and 4P+25). The pH and shear force values were significantly higher in T7 (3.5P fat and 4P+20 water) than those of other treatments. The lightness and redness were greatly reduced by increasing the quantity of water. The treatments containing 3P fat and 4P+20 water had the highest values of cohesiveness, springiness, gumminess, and chewiness. On the whole, when the protein (P) and fat (3P, 3.5P, 4P) levels were fixed, an increase over the appropriate moisture level deteriorated many physicochemical characteristics

    A Case of Inadvertent Anterior Chamber and Corneal Stromal Injection with Antibiotics during Cataract Operation

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    Purpose: To report a case of inadvertent anterior chamber and cornea stromal injection with high dose antibiotics and steroids during cataract operation. Methods: During cataract operation on a 78 year-old female patient, high dose gentamicin (20 mg/0.5 ml) and dexamethasone (2 mg/0.5 ml) were inadvertently injected into the anterior chamber and cornea stroma when making cornea edema for sealing of the incision sites. Anterior chamber irrigation with balanced salt solution (BSS) was immediately administered. On postoperative day one, extensive cornea edema was noted, and best-corrected visual acuity was 0.2. Descemet's membrane folds were observed around the corneal incision sites. Topical 5% NaCl and 1% prednisolone were started. Results: Four weeks postoperatively, corneal edema began to reduce significantly. At four months postoperatively, corneal edema fully resolved, and best-corrected visual acuity was 0.8. However, some Descemet's membrane folds still remained, and a decrease in the number of endothelial cells was noted by specular microscope. Conclusions: In this case involving anterior chamber and cornea stromal injection with high dose antibiotics and steroids, immediate anterior chamber irrigation with balanced salt solution seemed an appropriate management, and the patient's long-term visual acuity appears good. To prevent such mistakes, precise labeling of all solutions and use of different syringe needles should be considered.ope

    Evaluation of a Sodium–Water Reaction Event Caused by Steam Generator Tubes Break in the Prototype Generation IV Sodium-cooled Fast Reactor

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    AbstractThe prototype generation IV sodium-cooled fast reactor (PGSFR) has been developed by the Korea Atomic Energy Research Institute. This reactor uses sodium as a reactor coolant to transfer the core heat energy to the turbine. Sodium has chemical characteristics that allow it to violently react with materials such as a water or steam. When a sodium–water reaction (SWR) occurs due to leakage or breakage of steam generator tubes, high-pressure waves and corrosive reaction products are produced, which threaten the structural integrity of the components of the intermediate heat-transfer system (IHTS) and the safety of the primary heat-transfer system (PHTS). In the PGSFR, SWR events are included in the design-basis event. This event should be analyzed from the viewpoint of the integrities of the IHTS and fuel rods. To evaluate the integrity of the IHTS based on the consequences of the SWR, the behaviors of the generated high-pressure waves are analyzed at the major positions of a failed IHTS loop using a sodium–water advanced analysis method-II code. The integrity of the fuel rods must be consistently maintained below the safety acceptance criteria to avoid the consequences of the SWR. The integrity of the PHTS is evaluated using the multidimensional analysis of reactor safety-liquid metal reactor code to model the whole plant

    Two Cases of Primary Nasopharyngeal Tuberculosis

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    Nasopharyngeal tuberculosis can arise from both a primary infection and a secondary spread via the lymphatic or hematogenous system from a primary pulmonary lesion. Primary nasopharyngeal tuberculosis is rare and difficult to detect earlier because of the nonspecific presentations of the disease. As upper airway tuberculosis can be contagious, early initial diagnosis and suspicion of the physicians are needed in clinical practice. Recently, we successfully diagnosed and treated the disease by antitubercular medications of two cases of primary nasopharyngeal tuberculosis. Herein, we report our experience with a literature review

    Anti-proliferative effects of Bifidobacterium adolescentis SPM0212 extract on human colon cancer cell lines

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    <p>Abstract</p> <p>Background</p> <p>Lactic acid bacteria (LAB) are beneficial probiotic organisms that contribute to improved nutrition, microbial balance, and immuno-enhancement of the intestinal tract, as well as anti-tumor activity. The aim of the present work was to study the growth inhibition of tumor cells by butanol extract of <it>Bifidobacterium adolescentis </it>isolated from healthy young Koreans.</p> <p>Methods</p> <p>The anti-proliferative activity of <it>B. adolescentis </it>isolates was assessed by XTT assays on three human colon cancer cell lines (Caco-2, HT-29, and SW480). The effects of <it>B. adolescentis </it>SPM0212 butanol extract on tumor necrosis factor-α (TNF-α) and nitric oxide (NO) production were tested using the murine macrophage RAW 264.7 cell line.</p> <p>Results</p> <p>The butanol extract of <it>B. adolescentis </it>SPM0212 dose-dependently inhibited the growth of Caco-2, HT-29, and SW480 cells by 70%, 30%, and 40%, respectively, at 200 μg/mL. Additionally, the butanol extract of <it>B. adolescentis </it>SPM0212 induced macrophage activation and significantly increased the production of TNF-α and NO, which regulate immune modulation and are cytotoxic to tumor cells.</p> <p>Conclusion</p> <p>The butanol extract of <it>B. adolescentis </it>SPM0212 increased activity of the host immune system and may improve human health by helping to prevent colon cancer as a biological response modifier.</p

    Compositional assessment of carotenoid-biofortified rice using substantial equivalence

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    One important aspect in assessing the safety of genetically modified (GM) crops for human consumption is characterizing their nutrient composition. A β-carotene-biofortified rice was generated by inserting phytoene synthase (Psy) and carotene desaturase (Crtl) genes isolated from Capsicum and Pantoea into the genome of a conventional variety of rice (Nakdongbyeo). Nutrients (proximates, amino acids, fatty acids, minerals, and vitamins), anti-nutritive components (trypsin inhibitors and phytic acid), and ferulic acid in GM rice were compared with those in the parent line Nakdongbyeo. Statistical comparisons to test for equivalence showed that all of the analyzed components in the GM plants were equivalent to those in its non-transgenic counterpart, and most nutritional components fell within the range of values reported for other commercial lines, indicating the safety of the GM plant.Key words: Genetically modified crop, β-Carotene, Transgenic rice, Nutrient, Substantial equivalence
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