3,056 research outputs found

    First R and I Lights and Their Photometric Analyses of GSC 02393-00680

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    We obtained complete RR and II light curves of GSC 02393-00680 in 2008 and analyzed them with the 2003 version of the W-D code. It is shown that GSC 02393-00680 is a W-type shallow contact binary system with a high mass ratio q=1.600q=1.600 and a degree of contact factor f=5.0f=5.0%(\pm1.3%). It will be a good example to check up on the TRO theory. A period investigation based on all available data suggests that the system has a small-amplitude period oscillation (A3=0.d0030A_3=0.^{d}0030; T3=1.92T_3=1.92years). This may indicate it has a moderate mass close third body, which is similar to XY Leo

    p38α MAPK regulates proliferation and differentiation of osteoclast progenitors and bone remodeling in an aging-dependent manner.

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    Bone mass is determined by the balance between bone formation, carried out by mesenchymal stem cell-derived osteoblasts, and bone resorption, carried out by monocyte-derived osteoclasts. Here we investigated the potential roles of p38 MAPKs, which are activated by growth factors and cytokines including RANKL and BMPs, in osteoclastogenesis and bone resorption by ablating p38α MAPK in LysM+monocytes. p38α deficiency promoted monocyte proliferation but regulated monocyte osteoclastic differentiation in a cell-density dependent manner, with proliferating p38α-/- cultures showing increased differentiation. While young mutant mice showed minor increase in bone mass, 6-month-old mutant mice developed osteoporosis, associated with an increase in osteoclastogenesis and bone resorption and an increase in the pool of monocytes. Moreover, monocyte-specific p38α ablation resulted in a decrease in bone formation and the number of bone marrow mesenchymal stem/stromal cells, likely due to decreased expression of PDGF-AA and BMP2. The expression of PDGF-AA and BMP2 was positively regulated by the p38 MAPK-Creb axis in osteoclasts, with the promoters of PDGF-AA and BMP2 having Creb binding sites. These findings uncovered the molecular mechanisms by which p38α MAPK regulates osteoclastogenesis and coordinates osteoclastogenesis and osteoblastogenesis

    2-[3-Hy­droxy-4-(2-hy­droxy­eth­oxy)phen­yl]-4,4,5,5-tetra­methyl-2-imidazoline-1-oxyl 3-oxide

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    In the title compound, C15H21N2O5, the imidazoline ring displays a twisted conformation. The mean plane of the imidazoline ring makes a dihedral angle of 22.55 (5)° with the benzene ring. In the crystal, O—H⋯O and C—H⋯O hydrogen bonds link the mol­ecules into a layer parallel to the bc plane

    Sesquiterpenes from the marine red alga Laurencia composita.

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    Four new chamigrane derivatives, laurecomin A (1). laurecomin B (2), laurecomin C (3), and laurecomin D (4), one new naturally occurring sesquiterpene, 2,10-dibromo-3-chloro-7-chamigren-9-ol acetate (5), and three known halogenated structures, deoxyprepacifenol (6), 1-bromoselin-4(14),11-diene (7), and 9-bromoselin-4(14).11-diene (8), were isolated from the marine red alga Laurencia cornposita collected from Pingtan Island, China. The structures of these compounds were unambiguously established by 1D, 2D NMR and mass spectroscopic techniques. The bioassay results showed that 2 was active against both brine shrimp and fungus Colletotrichum lagenarium. (C) 2012 Elsevier B.V. All rights reserved.Four new chamigrane derivatives, laurecomin A (1). laurecomin B (2), laurecomin C (3), and laurecomin D (4), one new naturally occurring sesquiterpene, 2,10-dibromo-3-chloro-7-chamigren-9-ol acetate (5), and three known halogenated structures, deoxyprepacifenol (6), 1-bromoselin-4(14),11-diene (7), and 9-bromoselin-4(14).11-diene (8), were isolated from the marine red alga Laurencia cornposita collected from Pingtan Island, China. The structures of these compounds were unambiguously established by 1D, 2D NMR and mass spectroscopic techniques. The bioassay results showed that 2 was active against both brine shrimp and fungus Colletotrichum lagenarium. (C) 2012 Elsevier B.V. All rights reserved

    The environments of Type Ia supernovae with different relative equivalent width of Si II feature in their spectra

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    Although type Ia supernovae are so important in many astrophysical field, e.g. in cosmology, their explosion mechanism and progenitor system are still unclear. In physics, the relative equivalent width (REW) of the Si II 635.5 nm absorption feature reflects the velocity interval of silicon in the supernova ejecta and then may provide constraints on the explosion mechanism of SNe Ia. In this paper, we divide the SNe Ia into broad line (BL) and normal line (NL) subsamples based on their REW of Si II 635.5 nm absorption lines around maximum light, and find that the BL SNe Ia have a dimmer mean brightness than NL ones, which possibly results from their different metallicities. However, based on the pixel statistics study on the environments of two subsamples, we do not find any significant potential difference on the environments between BL and NL SNe Ia, which implies that the explosion mechanism of SNe Ia could be independent of their progenitor populations.Comment: 17 pages, 13 figures, accepted for publication in Ap

    Mesenchymal stem cells promote incision wound repair in a mouse model

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    Purpose: To investigate the wound healing process via the application of mesenchymal stem cells (MSCs) in a mouse model.Methods: MSCs were collected from the bone marrow of the femur and tibia of 6 – 12-week-old C57BL/6 mice. Full-thickness cutaneous wounds (4 × 2 cm) were made by incision on the dorsal side of the mice. The wound was then subjected to one of four random treatments: phosphate-buffered saline (PBS) solution, 3T3 fibroblasts, naive MSCs, or interferon gamma-activated MSCs. Chalkley method was used to determine vascular density. A score was given, for each field examined, for CD31-positive areas, and the results of blind analysis were confirmed by independent analysis of a second evaluator.Results: The tensile strength of the wound area was significantly lower in older versus younger mice (p ≤ 0.0007). Only one quarter of the mean force was required to disrupt wound integrity in older mice compared to young mice. Treatment with MSCs showed positive effects on wound healing. Activated MSCs showed the greatest efficacy at a dosage of 5 × 104 activated MSCs/8 cm2 of wound area or 6, 250 cells/cm2.Conclusion: The results suggest that MSC therapies enhance the tissue regeneration capacity in mice, especially in older populations, through effective transdifferentiation into the epithelium.Keywords: Mesenchymal stem cell, wound healing, mous

    Bile dynamics within the biliary tract and microfluidic-based bile component detection: A review

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    Bilestones are solid masses found in the gallbladder or biliary tract, which block the normal bile flow and eventually result in severe life-threatening complications. Studies have shown that bilestone formation may be related to bile flow dynamics and the concentration level of bile components. The bile flow dynamics in the biliary tract play a critical role in disclosing the mechanism of bile stasis and transportation. The concentration of bile composition is closely associated with processes such as nucleation and crystallization. Recently, microfluidic-based biosensors have been favored for multiple advantages over traditional bench-top detection assays for their less sample consumption, portability, low cost, and high sensitivity for real-time detection. Here, we reviewed the developments in bile dynamics study and microfluidics-based bile component detection methods. These studies may provide valuable insights into the bilestone formation mechanisms and better treatment, alongside our opinions on the future development of in vitro lithotriptic drug screening of bilestones and bile characterization tests
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