1,703 research outputs found

    Nitrate Reductase Activity, Nitrate Uptake and Iodine Speciation in the Marine Environment

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    The present method for the determination of new production (NP) by measuring the uptake of added 15NO3– suffers from a number of limitations. In an attempt to improve this situation, this research examined the possibility of estimating 15NO3– uptake by measuring the activity of nitrate reductase (NRA). In addition, because it has long been suspected that the biological reduction of IO3– to I– may be mediated by nitrate reductase (NR), this research investigated the ability of NR to catalyze the reduction of iodate to iodide. An improved method for the determination of NRA was developed. The sensitivity of this method is about five times higher than methods used in previous studies. NRA and 15NO3– uptake (NU) were determined over a wide range of nitrate concentrations in the East China Sea and in the adjoining Kuroshio Current in May, 1996. In light and nitrate-replete waters ([NO3–]\u3e1 ΞΌM, %PAR \u3e 10%, PAR: photosynthetically active radiance), NRA was linearly related to NP so that NRA may be used for estimating NP. A high ratio of NU/NRA was found in nitrate-depleted ([NO3–] \u3c 1 ΞΌM) and light-replete (%PAR \u3e 10%) conditions. The high ratio of NU/NRA data might have been caused by an overestimation of NU due to the stimulation of the addition of 15NO3– to nitrate-deficient water. This result revealed that NRA may be a reliable index for estimating new production in oligotrophic waters. In comparing NU in the literature with our NU values in different hydrographic realms, the NU values estimated from NRA fall well with recently reported values in similar types of waters. NRA and iodine speciation were measured in the East China Sea in May, 1996. The results suggest that the reduction of iodate to iodide in the upwelling areas is caused by the enzyme NR. In the process of iodate reduction, the depletion of iodate and the enrichment of iodide relative to the composition of the source water of a surface water mass represent an integration of NRA through the residence time of the water mass. A method for estimating the reduction of iodate to iodide by NR by using 125IO3– was developed. The reduction of IO3– to I– by NR was observed in the cultures of S. costatum and in natural phytoplankton assemblages. The rates were 0.008 to 0.019 n mol I– ΞΌg chl a–1 h–1 in natural samples. The iodate reduction rate was linearly related to NRA, suggesting that iodate reduction may be coupled to nitrate reduction

    An unusual timing for symptomatic chest pain in an adult chest wall myofibroma: a case report

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    INTRODUCTION: Myofibromas are benign mesenchymal neoplasms that can present as solitary and multicentric lesions. They can occur in several locations and can occur at any age from neonates to elderly patients. However, most of the lesions are found in neonates and babies. It rarely occurs in adults. CASE PRESENTATION: A 29-year-old Taiwanese man presented with persistent dull chest pain in his right lateral chest wall for 2 weeks. A chest X-ray showed a faint patchy opacity over the periphery of his right upper lung zone. Computed tomography and magnetic resonance imaging showed a lobulated mass at the intercostal space between his right fifth and sixth ribs with contrast enhancement and bone invasion. Malignancy could not be excluded. A percutaneous needle aspiration biopsy failed due to technique issues, so he underwent a thoracotomy and the tumor was excised with Marlex mesh repairs for the thoracic defect. Pathology confirmed a myofibroma without malignancy. He recovered uneventfully and no local recurrence was detected at the 1-year follow-up examination. CONCLUSIONS: Chest wall myofibroma presenting with chest pain has never been reported in adults. It is a challenge to differentiate myofibroma from malignancy in chest wall preoperatively, such as seen in our patient. To the best of our knowledge, this has not been previously reported in the scientific literature. Although myofibroma rarely occurs in the chest wall and adults, it must be suspected in any chest wall tumor presenting with chest pain

    On the Mass-Period Distributions and Correlations of Extrasolar Planets

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    In addition to fitting the data of 233 extra-solar planets with power laws, we construct a correlated mass-period distribution function of extrasolar planets, as the first time in this field. The algorithm to generate a pair of positively correlated beta-distributed random variables is introduced and used for the construction of correlated distribution functions. We investigate the mass-period correlations of extrasolar planets both in the linear and logarithm spaces, determine the confidence intervals of the correlation coefficients, and confirm that there is a positive mass-period correlation for the extrasolar planets. In addition to the paucity of massive close-in planets, which makes the main contribution on this correlation, there are other fine structures for the data in the mass-period plane.Comment: to be published in AJ, tentatively in December 200

    Out-Of-Band Management on UEFI System Firmware

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    The modern Redfish is a specification that utilize RESTful interface semantics to access data defined in model format to perform out-of-band (OOB) management through specific OOB software or hardware (such as Baseboard Management Controller, BMC). The OOB management allow users to configure system remotely when the system is in either power-off or power-on state. Industry can expect there are more and more pre-boot firmware drivers (like UEFI drivers) and system peripherals (such as PCI devices, PCI add-on-card and so on) support Redfish Schema/Configuration data model in the near future. This article describes the method to abstract the data communication/synchronization between UEFI drivers and OOB management on UEFI firmware environment. Furthermore, this article is not only restricted to single OOB management on system, the abstracts method described in this article is flexible and extensible to support multiple OOB management instances on one system simultaneously. Not only Redfish OOB management data model is supported, this article fulfills the requirements of any other data model of OOB managements such as OData XML/JSON data model, CIM-XML data model, 3rd party data model and etc

    Effects of natto extract on endothelial injury in a rat model

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    Vascular endothelial damage has been found to be associated with thrombus formation, which is considered to be a risk factor for cardiovascular disease. A diet of natto leads to a low prevalence of cardiovascular disease. The aim of the present study was to investigate the effects of natto extract on vascular endothelia damage with exposure to laser irradiation. Endothelial damage both in vitro and in vivo was induced by irradiation of rose bengal using a DPSS green laser. Cell viability was determined by MTS assay, and the intimal thickening was verified by a histological approach. The antioxidant content of natto extract was determined for the free radical scavenging activity. Endothelial cells were injured in the presence of rose bengal irradiated in a dose-dependent manner. Natto extract exhibits high levels of antioxidant activity compared with purified natto kinase. Apoptosis of laser-injured endothelial cells was significantly reduced in the presence of natto extract. Both the natto extract and natto kinase suppressed intimal thickening in rats with endothelial injury. The present findings suggest that natto extract suppresses vessel thickening as a synergic effect attributed to its antioxidant and anti-apoptosis properties

    A Novel Family of Cyst Proteins with Epidermal Growth Factor Repeats in Giardia lamblia

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    The biological goal of Giardia lamblia life cycle is differentiation into a cyst form (encystation) that can survive in the environment and infect a new host. Since cystic stages are key to transmission of parasites, this differentiation may be a target for interruption of the life cycle. Synthesis and assembly of the extracellular cyst wall are the major hallmarks of this important differentiation. During encystation, cyst wall structural proteins are coordinately synthesized and are mainly targeted to the cyst wall. However, only a few such proteins have been identified to date. In this study, we used a combination of bioinformatics and molecular approaches to identify new cyst structural proteins from G. lamblia and found a group of Epidermal Growth Factor (EGF)-like Repeats containing Cyst Proteins (EGFCPs). Interestingly, the levels of EGFCPs proteins increased significantly during encystation, which matches the characteristics of the Giardia cyst wall protein. Further characterization and localization studies suggest that EGFCPs may function like cyst wall proteins, involved in differentiation of G. lamblia trophozoites into cysts. Our results provide valuable information regarding the function of a new group of cyst proteins in parasite differentiation into cysts and help develop ways to interrupt the parasite life cycle
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