515 research outputs found
The Origin of Star Formation in Early-type Galaxies Inferred from Spatially Resolved Spectroscopy
We investigate the origin of star formation activity in early-type galaxies
with current star formation using spatially resolved spectroscopic data from
the Mapping Nearby Galaxies at APO (MaNGA) in the Sloan Digital Sky Survey
(SDSS). We first identify star-forming early-type galaxies from the SDSS
sample, which are morphologically early-type but show current star formation
activity in their optical spectra. We then construct comparison samples with
different combinations of star formation activity and morphology, which include
star-forming late-type galaxies, quiescent early-type galaxies and quiescent
late-type galaxies. Our analysis of the optical spectra reveals that the
star-forming early-type galaxies have two distinctive episodes of star
formation, which is similar to late-type galaxies but different from quiescent
early-type galaxies with a single star formation episode. Star-forming
early-type galaxies have properties in common with star-forming late-type
galaxies, which include stellar population, gas and dust content, mass and
environment. However, the physical properties of star-forming early-type
galaxies derived from spatially resolved spectroscopy differ from those of
star-forming late-type galaxies in the sense that the gas in star-forming
early-type galaxies is more concentrated than their stars, and is often
kinematically misaligned with stars. The age gradient of star-forming
early-type galaxies also differs from those of star-forming late-type galaxies.
Our findings suggest that the current star formation in star-forming early-type
galaxies has an external origin including galaxy mergers or accretion gas from
the cosmic web.Comment: 19 pages, 12 figures, Accepted for publication in Ap
The Connection between Star-Forming Galaxies, AGN Host Galaxies and Early-Type Galaxies in the SDSS
We present a study of the connection between star-forming galaxies, AGN host
galaxies, and normal early-type galaxies in the Sloan Digital Sky Survey
(SDSS). Using the SDSS DR5 and DR4plus data, we select our early-type galaxy
sample in the color versus color-gradient space, and we classify the spectral
types of the selected early-type galaxies into normal, star-forming, Seyfert,
and LINER classes, using several spectral line flux ratios. We investigate the
slope in the fundamental space for each class of early-type galaxies and find
that there are obvious differences in the slopes of the fundamental planes
(FPs) among the different classes of early-type galaxies, in the sense that the
slopes for Seyferts and star-forming galaxies are flatter than those for normal
galaxies and LINERs. This may be the first identification of the systematic
variation of the FP slope among the subclasses of early-type galaxies. The
difference in the FP slope might be caused by the difference in the degree of
nonhomology among different classes or by the difference of gas contents in
their merging progenitors. One possible scenario is that the AGN host galaxies
and star-forming galaxies are formed by gas-rich merging and that they may
evolve into normal early-type galaxies after finishing their star formation or
AGN activities.Comment: 5 pages with emulateapj, 2 figures, accepted for publication in the
Astrophysical Journal Letter
Overexpression of Arabidopsis thaliana brassinosteroid-related acyltransferase 1 gene induces brassinosteroid-deficient phenotypes in creeping bentgrass
Brassinosteroids (BRs) are naturally occurring steroidal hormones that play diverse roles in various processes during plant growth and development. Thus, genetic manipulation of endogenous BR levels might offer a way of improving the agronomic traits of crops, including plant architecture and stress tolerance. In this study, we produced transgenic creeping bentgrass (Agrostis stolonifera L.) overexpressing a BR-inactivating enzyme, Arabidopsis thaliana BR-related acyltransferase 1 (AtBAT1), which is known to catalyze the conversion of BR intermediates to inactive acylated conjugates. After putative transgenic plants were selected using herbicide resistance assay, genomic integration of the AtBAT1 gene was confirmed by genomic PCR and Southern blot analysis, and transgene expression was validated by northern blot analysis. The transgenic creeping bentgrass plants exhibited BR-deficient phenotypes, including reduced plant height with shortened internodes (i.e., semi-dwarf), reduced leaf growth rates with short, wide, and thick architecture, high chlorophyll contents, decreased numbers of vascular bundles, and large lamina joint bending angles (i.e., erect leaves). Subsequent analyses showed that the transgenic plants had significantly reduced amounts of endogenous BR intermediates, including typhasterol, 6-deoxocastasterone, and castasterone. Moreover, the AtBAT1 transgenic plants displayed drought tolerance as well as delayed senescence. Therefore, the results of the present study demonstrate that overexpression of an Arabidopsis BR-inactivating enzyme can reduce the endogenous levels of BRs in creeping bentgrass resulting in BR-deficient phenotypes, indicating that the AtBAT1 gene from a dicot plant is also functional in the monocot crop.111Ysciescopu
Anti-amyloidogenic effect of menaquinone-7 on betaamyloid production and aggregation
Purpose: To investigate the beneficial effects of menaquinone-7 (MK-7), an isoform of vitamin K2, against beta-amyloid (AΞ²) production and aggregation in Alzheimer's disease using in vitro assays. Methods: The cytotoxicity of MK-7 was determined by MTT assay. The amount of AΞ² produced and secreted into the supernatant by APP-CHO cells treated with MK-7 was evaluated by ELISA. The expression of Ξ²-secretases and ADAM10, a representative Ξ±-secretase, was determined using western blot analysis. The production of sAPPΞ² and sAPPΞ± fragments generated by Ξ²-secretases and Ξ±secretase, respectively, were also determined by western blot analysis. The effect on AΞ² aggregation was assessed using Thioflavin T (Th T) assay. Results: MK-7 (up to 75 nM) significantly decreased AΞ² production in APP-CHO cells. This was accompanied by decreased expression of Ξ²-secretase and lower production of sAPPΞ² (p < 0.05). However, expression of ADAM10 and production of sAPPΞ± were not significantly affected. In contrast, MK-7 significantly decreased AΞ² aggregation in a dose-dependent manner (p < 0.05). Conclusion: MK-7 exerts anti-amyloidogenic effects via decreased production and lower aggregation of AΞ² into oligomers and fibrils. Therefore, dietary supplementation with MK-7 may be beneficial for the prevention of Alzheimerβs disease
Nuclear starburst activity induced by elongated bulges in spiral galaxies
We study the effects of bulge elongation on the star formation activity in
the centers of spiral galaxies using the data from the Sloan Digital Sky Survey
Data Release 7. We construct a volume-limited sample of face-on spiral galaxies
with 19.5 mag at 0.02 0.055 by excluding barred galaxies,
where the aperture of the SDSS spectroscopic fibre covers the bulges of the
galaxies. We adopt the ellipticity of bulges measured by Simard et al. (2011)
who performed two-dimensional bulge+disc decompositions using the SDSS images
of galaxies, and identify nuclear starbursts using the fibre specific star
formation rates derived from the SDSS spectra. We find a statistically
significant correlation between bulge elongation and nuclear starbursts in the
sense that the fraction of nuclear starbursts increases with bulge elongation.
This correlation is more prominent for fainter and redder galaxies, which
exhibit higher ratios of elongated bulges. We find no significant environmental
dependence of the correlation between bulge elongation and nuclear starbursts.
These results suggest that non-axisymmetric bulges can efficiently feed the gas
into the centre of galaxies to trigger nuclear starburst activity.Comment: 9 pages, 7 figures, accepted for publication in MNRA
Aberrant phenotypes of transgenic mice expressing dimeric human erythropoietin
<p>Abstract</p> <p>Background</p> <p>Dimeric human erythropoietin (dHuEPO) peptides are reported to exhibit significantly higher biological activity than the monomeric form of recombinant EPO. The objective of this study was to produce transgenic (tg) mice expressing dHuEPO and to investigate the characteristics of these mice.</p> <p>Methods</p> <p>A dHuEPO-expressing vector under the control of the goat beta-casein promoter, which produced a dimer of human EPO molecules linked by a 2-amino acid peptide linker (Asp-Ile), was constructed and injected into 1-cell fertilized embryos by microinjection. Mice were screened using genomic DNA samples obtained from tail biopsies. Blood samples were obtained by heart puncture using heparinized tubes, and hematologic parameters were assessed. Using the microarray analysis tool, we analyzed differences in gene expression in the spleens of tg and control mice.</p> <p>Results</p> <p>A high rate of spontaneous abortion or death of the offspring was observed in the recipients of dHuEPO embryos. We obtained 3 founder lines (#4, #11, and #47) of tg mice expressing the <it>dHuEPO </it>gene. However, only one founder line showed stable germline integration and transmission, subsequently establishing the only transgenic line (#11). We obtained 2 F1 mice and 3 F2 mice from line #11. The dHuEPO protein could not be obtained because of repeated spontaneous abortions in the tg mice. Tg mice exhibited symptoms such as short lifespan and abnormal blood composition. The red blood cell count, white blood cell count, and hematocrit levels in the tg mice were remarkably higher than those in the control mice. The spleens of the tg mice (F1 and F2 females) were 11- and -21-fold larger than those of the control mice. Microarray analysis revealed 2,672 spleen-derived candidate genes; more genes were downregulated than upregulated (849/764). Reverse transcriptase-polymerase chain reaction (RT-PCR) and quantitative real-time PCR (qRT-PCR) were used for validating the results of the microarray analysis of mRNA expression.</p> <p>Conclusions</p> <p>In conclusion, dHuEPO tg mice caused excessive erythrocytosis that led to abnormal blood composition, short lifespan, and abnormal splenomegaly. Further, we identified 2,672 genes associated with splenomegaly by microarray analysis. These results could be useful in the development of dHuEPO-producing tg animals.</p
Reproducibility and diagnostic performance of the vascular index of superb microvascular imaging in real-time breast ultrasonography for evaluating breast masses
Purpose This study aimed to evaluate the reproducibility and diagnostic performance of a quantitative parameter of superb microvascular imaging (SMI) in real-time breast ultrasonography (US) for differentiating benign from malignant breast masses. Methods Eighty-seven breast masses in 75 patients who underwent both B-mode US and SMI before US-guided core needle biopsy were included in this study. Two radiologists performed B-mode US and measured the vascular index (VI) of SMI respectively for each lesion in real time. Intraobserver and interobserver agreements were analyzed for the VI of SMI. The diagnostic performance of B-mode US using the Breast Imaging Reporting and Database System lexicon and combined use with the VI of SMI was evaluated compared to pathology. Results The median VI of malignant masses (n=32) was significantly higher than that of benign masses (n=55) (7.6% and 2.6%, respectively; P<0.001). The intraobserver agreement for VI was excellent regardless of the pathology, size, or depth of the lesion. The interobserver agreement for VI was excellent regardless of the presence of a measurement interval. The interobserver agreement for the final diagnostic decision was improved by combining B-mode US and VI (ΞΊ=0.883) in comparison with B-mode US only (ΞΊ=0.617). Adding VI led to significant improvements in the specificity (87.2% vs. 52.7%, 83.6% vs. 49.0%), accuracy (89.7% vs. 69.3%, 84.0% vs. 65.9%) and positive predictive value (81.5% vs. 55.1%, 75.6% vs. 52.6%) of B-mode US for both observers compared with B-mode US alone (all, P=0.001). Conclusion The VI of SMI for real-time breast US is highly reproducible and leads to improved diagnostic performance for differentiating between benign and malignant breast lesions in combination with B-mode US
Acute Diffuse Phlegmonous Esophagogastritis: A Case Report
Acute phlegmonous infection of the gastrointestinal tract is characterized by purulent inflammation of the submucosa and muscular layer with sparing of the mucosa. The authors report a rare case of acute diffuse phlegmonous esophagogastritis, which was well diagnosed based on the typical chest computed tomographic (CT) findings and was successfully treated. A 48-yr-old man presented with left chest pain and dyspnea for three days. Chest radiograph on admission showed mediastinal widening and bilateral pleural effusion. The patient became febrile and the amount of left pleural effusion is increased on follow-up chest radiograph. Left closed thoracostomy was performed with pus drainage. A CT diagnosis of acute phlegmonous esophagogastritis was suggested and a surgery was decided due to worsening of clinical condition of the patient and radiologic findings. Esophageal myotomies were performed and the submucosal layer was filled with thick, cheesy materials. The patient was successfully discharged with no postoperative complication
ΠΡΠΎΡΡΠΎΠΉ ΠΈ ΡΡΡΠ΅ΠΊΡΠΈΠ²Π½ΡΠΉ ΠΌΠ΅ΡΠΎΠ΄ Π΄ΠΈΠ°Π·ΠΎΡΠΈΡΠΎΠ²Π°Π½ΠΈΡ-ΠΈΠΎΠ΄ΠΈΡΠΎΠ²Π°Π½ΠΈΡ Π°ΡΠΎΠΌΠ°ΡΠΈΡΠ΅ΡΠΊΠΈΡ Π°ΠΌΠΈΠ½ΠΎΠ² Π² Π²ΠΎΠ΄Π½ΡΡ ΠΏΠ°ΡΡΠ°Ρ ΠΏΠΎΠ΄ Π΄Π΅ΠΉΡΡΠ²ΠΈΠ΅ΠΌ ΡΠΈΡΡΠ΅ΠΌ: NaNO[2]/ΠΏ-ΡΠΎΠ»ΡΠΎΠ»ΡΡΠ»ΡΡΠΎΠΊΠΈΡΠ»ΠΎΡΠ° ΠΈ NaNO[2]/NaHSO[4]
ΠΡΠ΅Π΄Π»Π°Π³Π°Π΅ΡΡΡ Π½ΠΎΠ²ΡΠΉ, ΡΠ΄ΠΎΠ±Π½ΡΠΉ ΠΈ ΡΡΡΠ΅ΠΊΡΠΈΠ²Π½ΡΠΉ ΠΌΠ΅ΡΠΎΠ΄ ΠΏΠΎΠ»ΡΡΠ΅Π½ΠΈΡ Π°ΡΠΎΠΌΠ°ΡΠΈΡΠ΅ΡΠΊΠΈΡ
ΠΈΠΎΠ΄ΠΈΠ΄ΠΎΠ² ΠΈΠ· Π°Π½ΠΈΠ»ΠΈΠ½ΠΎΠ² ΡΠ΅Π°ΠΊΡΠΈΠ΅ΠΉ Π΄ΠΈΠ°Π·ΠΎΡΠΈΡΠΎΠ²Π°Π½ΠΈΡ-ΠΈΠΎΠ΄ΠΈΡΠΎΠ²Π°Π½ΠΈΡ ΠΏΠΎΠ΄ Π΄Π΅ΠΉΡΡΠ²ΠΈΠ΅ΠΌ NaNO[2]/KI/p-TsOH ΠΈΠ»ΠΈ NaHSO[4] ΠΏΡΠΈ 20 Β°Π‘ Π² Π²ΠΎΠ΄Π½ΠΎΠΉ ΠΏΠ°ΡΡΠ΅. Π Π°Π·ΡΠ°Π±ΠΎΡΠ°Π½Π½ΡΠΉ ΠΌΠ΅ΡΠΎΠ΄ ΠΎΡΠ²Π΅ΡΠ°Π΅Ρ ΡΡΠ΅Π±ΠΎΠ²Π°Π½ΠΈΡΠΌ "Π·Π΅Π»Π΅Π½ΠΎΠΉ Ρ
ΠΈΠΌΠΈΠΈ", ΠΏΡΠ΅Π΄ΡΡΠ²Π»ΡΠ΅ΠΌΡΠΌ ΠΊ ΡΠΎΠ²ΡΠ΅ΠΌΠ΅Π½Π½ΡΠΌ Ρ
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