719 research outputs found

    Pure iron grains are rare in the universe

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    The abundant forms in which the major elements in the universe exist have been determined from numerous astronomical observations and meteoritic analyses. Iron (Fe) is an exception, in that only depletion of gaseous Fe has been detected in the interstellar medium, suggesting that Fe is condensed into a solid, possibly the astronomically invisible metal. To determine the primary form of Fe, we replicated the formation of Fe grains in gaseous ejecta of evolved stars by means of microgravity experiments. We found that the sticking probability for formation of Fe grains is extremely small; only several atoms will stick per hundred thousand collisions, so that homogeneous nucleation of metallic Fe grains is highly ineffective, even in the Fe-rich ejecta of Type Ia supernovae. This implies that most Fe is locked up as grains of Fe compounds or as impurities accreted onto other grains in the interstellar medium

    Construction of Identity and Time Perspective for College Students

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    Past studies dealing with the effects of time perspective on identity construction have lacked a time integration point of view. This paper presents the effects from the perspective of college students and arrives at the following conclusions. (1) Achievement and diffusion status have intermixed both high and low time integration groups. (2) However, foreclosure status has a relatively high integration, whereas moratorium status has a low integration. The above conclusions suggest that for foreclosure and moratorium status, time integration is more important as compared to achievement and diffusion status. On the other hand, some problems are indicated on the scale with respect to categorizing four identity statuses. Finally, the paper discusses several suggestions for future studies

    Contribution of fly ash to mortar strength development under steam and internal curing

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    The purpose of this study is to quantitatively evaluate the effects of steam curing and internal curing on contribution of fly ash to strength development of mortar by using cementing efficiency factor (k-value) that represents strength development performance as a binder of fly ash. In addition, the pozzolanic reaction of fly ash was evaluated from the viewpoint of calcium hydroxide consumption by using thermogravimetry and differential thermal analysis as well as the degree of fly ash reaction by using selective dissolution method. The result indicated that steam curing improved early compressive strength and internal curing improved compressive strength and k-value at all ages. Also, a linearrelationship between the degree of fly ash reaction and the k-value was shown regardless of the age and the replacement ratio of fly ash

    Ovariectomy enhances renal cortical expression and function of cyclooxygenase-2

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    Ovariectomy enhances renal cortical expression and function of cyclooxygenase-2.BackgroundCyclooxygenase-2 (COX-2) inhibitors are used as analgesics in postmenopausal women, who develop edema and require a salt-restricted diet. This study was performed to determine the renal expression of COX-2 and on COX-2–dependent regulation of renal blood flow (RBF) in ovariectomized rats.MethodsSprague-Dawley rats were divided into 4 groups: sham-operated rats fed a normal-salt diet (Sh+NS) or a low-salt diet (Sh+LS), and bilaterally ovariectomized rats fed a normal-salt diet (Ox+NS) or a low-salt diet (Ox+LS) (N = 6 in each group). Estrogen replacement therapy was performed on other ovariectomized rats. A renal clearance study was performed in anesthetized animals.ResultsOvariectomy increased renal cortical COX-2 expression independently of dietary salt intake (Sh+NS <Ox+N; Sh+LS <Ox+LS). Inhibition of COX-2 by NS398 reduced the urinary excretion of 6-keto-prostaglandin F1α in all 4 groups, although the reduction was greater in the Ox+LS group than in the Ox+NS and Sh+LS groups, which in turn had a greater reduction than the Sh+NS group. RBF significantly decreased in every group except the Sh+NS group, but no effect on blood pressure, inulin clearance, or urinary sodium excretion was seen. The decrease in RBF was significantly greater in the Ox+LS group than in the Sh+LS and Ox+NS group. The decrease in RBF was dependent on cortical RBF in the Sh+LS and Ox+NS groups, and on both cortical and medullary RBF in the Ox+LS group. Estrogen replacement therapy reversed the ovariectomy-induced changes.ConclusionEstrogen-dependent COX-2 expression plays an important role in the RBF regulation in female rats

    Immunohistochemical Analysis of CXCR4 Expression in Fibrohistiocytic Tumors

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    Functional chemokine receptors are expressed in many malignant tumors. These receptors promote tumor growth and metastasis in response to endogenous chemokines. We analyzed the expression of CXCR4, CCR6 and CCR7 in fibrohistiocytic tumors, including dermatofibrosarcoma protuberance (DFSP), malignant fibrous histiocytoma (MFH), dermatofibroma (DF) using immunohistochemistry. We also investigated the relationship between CXCR4 and CD34, the latter of which is an immunohistochemical marker for DFSP. We observed a higher expression of CXCR4 in DFSP and MFH as compared with DF. Interestingly, a significantly higher expression of CXCR4 was detected in relapsed DFSP than in non-relapsed DFSP, but no significant differences were detected between non-relapsed DFSP and DFSP with CD34 immunostaining. Moreover, MFH had strong immunoreactivity for CXCR4, CCR6 and CCR7. These findings suggest that the assessment of CXCR4 immunoreactivity in fibrohistiocytic tumors is a useful tool for predicting tumor aggressiveness

    Pastiche Steel Ensemble on Tour

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    Kennesaw State University School of Music presents Pastiche Steel Ensemble, a diverse group of pannists and musicians hailing from different countries around the world and transcends stereotypes surrounding the limitations of the steelpan while breaking boundaries of steelpan performance with original compositions, arrangements, and familiar music.https://digitalcommons.kennesaw.edu/musicprograms/1693/thumbnail.jp

    Characteristic expression of twelve rice PR1 family genes in response to pathogen infection, wounding, and defense-related signal compounds (121/180)

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    Pathogenesis-related (PR) proteins have been used as markers of plant defense responses, and are classified into 17 families. However, precise information on the majority members in specific PR families is still limited. We were interested in the individual characteristics of rice PR1 family genes, and selected 12 putatively active genes using rice genome databases for expressed genes. All were upregulated upon compatible and/or incompatible rice-blast fungus interactions; three were upregulated in the early infection period and four in the late infection period. Upon compatible rice–bacterial blight interaction, four genes were upregulated, six were not affected, and one was downregulated. These results are in striking contrast to those among 22 ArabidopsisPR1 genes where only one gene was pathogen-inducible. The responses of individual genes to salicylic acid, jasmonic acid, and ethylene induced defense signaling pathways in rice are likely to be different from those in dicot plants. Transcript levels in healthy leaves, roots, and flowers varied according to each gene. Analysis of the partially overlapping expression patterns of rice PR1 genes in healthy tissues and in response to pathogens and other stresses would be useful to understand their possible functions and for use as characteristic markers for defense-related studies in rice

    Updating International Japan Studies Education with ICT Tools: A Problem-based Learning Approach to Teaching about Akutagawa Ryunosuke's “Hana” and Japanese Modernization

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    This paper describes a PBL-based active learning approach using ICT tools for Japanese education that is appropriate for the digital age. Based on the existing literature on PBL, we designed a two-week PBL program in which a total of eight learners in three distinct countries (Japan, Spain, and China) collaboratively studied and read Hana (“The Nose”), a short story published by the Japanese writer Ryunosuke Akutagawa, to gain insight into the nature of Japanese modernization. Despite their limited prior exposure to Japanese classics, all learners clearly demonstrated a recognizable improvement in their understanding of the text at the end of the PBL program through the mid and final presentations. They also provided positive evaluations of their PBL experiences. Some remaining issues are discussed based on these data and instructors’ reflections on PBL

    Opposing role of condensin hinge against replication protein A in mitosis and interphase through promoting DNA annealing

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    Condensin is required for chromosome dynamics and diverse DNA metabolism. How condensin works, however, is not well understood. Condensin contains two structural maintenance of chromosomes (SMC) subunits with the terminal globular domains connected to coiled-coil that is interrupted by the central hinge. Heterotrimeric non-SMC subunits regulate SMC. We identified a novel fission yeast SMC hinge mutant, cut14-Y1, which displayed defects in DNA damage repair and chromosome segregation. It contains an amino acid substitution at a conserved hinge residue of Cut14/SMC2, resulting in diminished DNA binding and annealing. A replication protein A mutant, ssb1-418, greatly alleviated the repair and mitotic defects of cut14-Y1. Ssb1 protein formed nucleolar foci in cut14-Y1 cells, but the number of foci was diminished in cut14-Y1 ssb1-418 double mutants. Consistent with the above results, Ssb1 protein bound to single-strand DNA was removed by condensin or the SMC dimer through DNA reannealing in vitro. Similarly, RNA hybridized to DNA may be removed by the SMC dimer. Thus, condensin may wind up DNA strands to unload chromosomal components after DNA repair and prior to mitosis. We show that 16 suppressor mutations of cut14-Y1 were all mapped within the hinge domain, which surrounded the original L543 mutation site
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