61 research outputs found

    Survey of Period Variations of Superhumps in SU UMa-Type Dwarf Novae

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    We systematically surveyed period variations of superhumps in SU UMa-type dwarf novae based on newly obtained data and past publications. In many systems, the evolution of superhump period are found to be composed of three distinct stages: early evolutionary stage with a longer superhump period, middle stage with systematically varying periods, final stage with a shorter, stable superhump period. During the middle stage, many systems with superhump periods less than 0.08 d show positive period derivatives. Contrary to the earlier claim, we found no clear evidence for variation of period derivatives between superoutburst of the same object. We present an interpretation that the lengthening of the superhump period is a result of outward propagation of the eccentricity wave and is limited by the radius near the tidal truncation. We interpret that late stage superhumps are rejuvenized excitation of 3:1 resonance when the superhumps in the outer disk is effectively quenched. Many of WZ Sge-type dwarf novae showed long-enduring superhumps during the post-superoutburst stage having periods longer than those during the main superoutburst. The period derivatives in WZ Sge-type dwarf novae are found to be strongly correlated with the fractional superhump excess, or consequently, mass ratio. WZ Sge-type dwarf novae with a long-lasting rebrightening or with multiple rebrightenings tend to have smaller period derivatives and are excellent candidate for the systems around or after the period minimum of evolution of cataclysmic variables (abridged).Comment: 239 pages, 225 figures, PASJ accepte

    Why Are Outcomes Different for Registry Patients Enrolled Prospectively and Retrospectively? Insights from the Global Anticoagulant Registry in the FIELD-Atrial Fibrillation (GARFIELD-AF).

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    Background: Retrospective and prospective observational studies are designed to reflect real-world evidence on clinical practice, but can yield conflicting results. The GARFIELD-AF Registry includes both methods of enrolment and allows analysis of differences in patient characteristics and outcomes that may result. Methods and Results: Patients with atrial fibrillation (AF) and ≥1 risk factor for stroke at diagnosis of AF were recruited either retrospectively (n = 5069) or prospectively (n = 5501) from 19 countries and then followed prospectively. The retrospectively enrolled cohort comprised patients with established AF (for a least 6, and up to 24 months before enrolment), who were identified retrospectively (and baseline and partial follow-up data were collected from the emedical records) and then followed prospectively between 0-18 months (such that the total time of follow-up was 24 months; data collection Dec-2009 and Oct-2010). In the prospectively enrolled cohort, patients with newly diagnosed AF (≤6 weeks after diagnosis) were recruited between Mar-2010 and Oct-2011 and were followed for 24 months after enrolment. Differences between the cohorts were observed in clinical characteristics, including type of AF, stroke prevention strategies, and event rates. More patients in the retrospectively identified cohort received vitamin K antagonists (62.1% vs. 53.2%) and fewer received non-vitamin K oral anticoagulants (1.8% vs . 4.2%). All-cause mortality rates per 100 person-years during the prospective follow-up (starting the first study visit up to 1 year) were significantly lower in the retrospective than prospectively identified cohort (3.04 [95% CI 2.51 to 3.67] vs . 4.05 [95% CI 3.53 to 4.63]; p = 0.016). Conclusions: Interpretations of data from registries that aim to evaluate the characteristics and outcomes of patients with AF must take account of differences in registry design and the impact of recall bias and survivorship bias that is incurred with retrospective enrolment. Clinical Trial Registration: - URL: http://www.clinicaltrials.gov . Unique identifier for GARFIELD-AF (NCT01090362)

    Risk profiles and one-year outcomes of patients with newly diagnosed atrial fibrillation in India: Insights from the GARFIELD-AF Registry.

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    BACKGROUND: The Global Anticoagulant Registry in the FIELD-Atrial Fibrillation (GARFIELD-AF) is an ongoing prospective noninterventional registry, which is providing important information on the baseline characteristics, treatment patterns, and 1-year outcomes in patients with newly diagnosed non-valvular atrial fibrillation (NVAF). This report describes data from Indian patients recruited in this registry. METHODS AND RESULTS: A total of 52,014 patients with newly diagnosed AF were enrolled globally; of these, 1388 patients were recruited from 26 sites within India (2012-2016). In India, the mean age was 65.8 years at diagnosis of NVAF. Hypertension was the most prevalent risk factor for AF, present in 68.5% of patients from India and in 76.3% of patients globally (P < 0.001). Diabetes and coronary artery disease (CAD) were prevalent in 36.2% and 28.1% of patients as compared with global prevalence of 22.2% and 21.6%, respectively (P < 0.001 for both). Antiplatelet therapy was the most common antithrombotic treatment in India. With increasing stroke risk, however, patients were more likely to receive oral anticoagulant therapy [mainly vitamin K antagonist (VKA)], but average international normalized ratio (INR) was lower among Indian patients [median INR value 1.6 (interquartile range {IQR}: 1.3-2.3) versus 2.3 (IQR 1.8-2.8) (P < 0.001)]. Compared with other countries, patients from India had markedly higher rates of all-cause mortality [7.68 per 100 person-years (95% confidence interval 6.32-9.35) vs 4.34 (4.16-4.53), P < 0.0001], while rates of stroke/systemic embolism and major bleeding were lower after 1 year of follow-up. CONCLUSION: Compared to previously published registries from India, the GARFIELD-AF registry describes clinical profiles and outcomes in Indian patients with AF of a different etiology. The registry data show that compared to the rest of the world, Indian AF patients are younger in age and have more diabetes and CAD. Patients with a higher stroke risk are more likely to receive anticoagulation therapy with VKA but are underdosed compared with the global average in the GARFIELD-AF. CLINICAL TRIAL REGISTRATION-URL: http://www.clinicaltrials.gov. Unique identifier: NCT01090362

    Materiał wypełniający z popiołem lotnym i żużlem jako środkiem smarnym w przeciskaniu rur pod kwaśnymi gruntami siarczanowymi

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    The pipe jacking method is relatively reasonable among trenchless construction methods. For the application of this method, the acid sulfate soils have negative impacts on filling materials (one of the cement materials) injected into the tail-void which are over-cutting areas formed to reduce the friction between the pipes and the surrounding soils. In this study, the application of fly ash and slag is discussed to minimize the effect of sulfur acid to filling materials. As the results of the experiments, the addition of fly ash and slag can control the gelling time and prevent the reduction of uniaxial strength of filling materials under the acid sulfate soils. In addition, the filling materials added slag lowered frictional resistance compared to that of fly ash. Filling materials with the lower frictional resistance are preferred to apply for the smooth pipe jacking constructions. Therefore, filling materials added slag would show better performance than that of fly ash under the acid sulfate soils due to its lower frictional resistance.Metoda przeciskania rur jest zaliczana do metod budowy bezwykopowej. W przypadku zastosowania tej metody kwaśne gleby siarczanowe mają negatywny wpływ na materiały wypełniające (jeden z materiałów cementowych) wstrzykiwane w pustkę końcową, które są obszarami utworzonymi w celu zmniejszenia tarcia między rurami a otaczającymi glebami. W artykule omówiono zastosowanie popiołu lotnego i żużla w celu zminimalizowania wpływu kwasu siarkowego na materiały wypełniające. W wyniku eksperymentów stwierdzono, że dodanie popiołu lotnego i żużla pozwala na kontrolowanie czasu żelowania i zapobiega zmniejszeniu jednoosiowej wytrzymałości materiałów wypełniających. Ponadto dodany materiał wypełniający obniżył opór tarcia w porównaniu z popiołem lotnym. W przypadku gładkich konstrukcji rurowych zaleca się stosowanie materiałów wypełniających o niższym oporze tarcia. Dlatego dodany żużel z materiałów wypełniających wykazywałby lepszą wydajność niż popioły lotne ze względu na niższy opór tarcia

    Study on Control of Wall Deflection in Earth Stepped-Twin Retaining Wall Using Anchor Method by means of Numerical Simulation

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    The demand for specific earth retaining wall methods is increasing along with the advancement and overcrowding of underground space use such as the presence of adjacent structures in an urban area. To cope with this, the method named earth stepped-twin retaining wall is increasingly being applied. However, there is a concern about the workplace if the earth pressure causes a heaving and pressing phenomenon from both ends of the retaining wall in the earth stepped-twin retaining wall. Therefore, we proposed the application of an anchor method that contains the inner and outer walls by using numerical simulation. The effects of the difference in soil properties, the horizontal distance between the outer and inner walls, and the depth of the outer wall embedment on the anchor were investigated. The results of this study show that the wall deflection of the inner wall could improve by adopting the anchor support. Besides, it was found that the inner wall can be efficiently suppressed by adopting the hybrid system with anchors and struts according to the soil properties, horizontal distance, and the depth of the outer wall

    Extracellular Vesicles from Amnion-Derived Mesenchymal Stem Cells Ameliorate Hepatic Inflammation and Fibrosis in Rats

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    Background. There are no approved drug treatments for liver fibrosis and nonalcoholic steatohepatitis (NASH), an advanced stage of fibrosis which has rapidly become a major cause of cirrhosis. Therefore, development of anti-inflammatory and antifibrotic therapies is desired. Mesenchymal stem cell- (MSC-) based therapy, which has been extensively investigated in regenerative medicine for various organs, can reportedly achieve therapeutic effect in NASH via paracrine action. Extracellular vesicles (EVs) encompass a variety of vesicles released by cells that fulfill functions similar to those of MSCs. We herein investigated the therapeutic effects of EVs from amnion-derived MSCs (AMSCs) in rats with NASH and liver fibrosis. Methods. NASH was induced by a 4-week high-fat diet (HFD), and liver fibrosis was induced by intraperitoneal injection of 2 mL/kg 50% carbon tetrachloride (CCl4) twice a week for six weeks. AMSC-EVs were intravenously injected at weeks 3 and 4 in rats with NASH (15 μg/kg) and at week 3 in rats with liver fibrosis (20 μg/kg). The extent of inflammation and fibrosis was evaluated with quantitative reverse transcription polymerase chain reaction and immunohistochemistry. The effect of AMSC-EVs on inflammatory and fibrogenic response was investigated in vitro. Results. AMSC-EVs significantly decreased the number of Kupffer cells (KCs) in the liver of rats with NASH and the mRNA expression levels of inflammatory cytokines such as tumor necrosis factor- (Tnf-) α, interleukin- (Il-) 1β and Il-6, and transforming growth factor- (Tgf-) β. Furthermore, AMSC-EVs significantly decreased fiber accumulation, KC number, and hepatic stellate cell (HSC) activation in rats with liver fibrosis. In vitro, AMSC-EVs significantly inhibited KC and HSC activation and suppressed the lipopolysaccharide (LPS)/toll-like receptor 4 (TLR4) signaling pathway. Conclusions. AMSC-EVs ameliorated inflammation and fibrogenesis in a rat model of NASH and liver fibrosis, potentially by attenuating HSC and KC activation. AMSC-EV administration should be considered as a new therapeutic strategy for chronic liver disease

    Human VAP-C Negatively Regulates Hepatitis C Virus Propagation▿

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    Human vesicle-associated membrane protein-associated protein (VAP) subtype A (VAP-A) and subtype B (VAP-B) are involved in the regulation of membrane trafficking, lipid transport and metabolism, and the unfolded protein response. VAP-A and VAP-B consist of the major sperm protein (MSP) domain, the coiled-coil motif, and the C-terminal transmembrane anchor and form homo- and heterodimers through the transmembrane domain. VAP-A and VAP-B interact with NS5B and NS5A of hepatitis C virus (HCV) through the MSP domain and the coiled-coil motif, respectively, and participate in the replication of HCV. VAP-C is a splicing variant of VAP-B consisting of the N-terminal half of the MSP domain of VAP-B followed by the subtype-specific frameshift sequences, and its biological function has not been well characterized. In this study, we have examined the biological functions of VAP-C in the propagation of HCV. VAP-C interacted with NS5B but not with VAP-A, VAP-B, or NS5A in immunoprecipitation analyses, and the expression of VAP-C inhibited the interaction of NS5B with VAP-A or VAP-B. Overexpression of VAP-C impaired the RNA replication of the HCV replicon and the propagation of the HCV JFH1 strain, whereas overexpression of VAP-A and VAP-B enhanced the replication. Furthermore, the expression of VAP-C was observed in various tissues, whereas it was barely detected in the liver. These results suggest that VAP-C acts as a negative regulator of HCV propagation and that the expression of VAP-C may participate in the determination of tissue tropism of HCV propagation
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