4,779 research outputs found

    Prevalence and diagnosis of congenital uterine anomalies in women with reproductive failure: a critical appraisal

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    BACKGROUND: The prevalence of congenital uterine anomalies in women with reproductive failure remains unclear, largely due to methodological bias. The aim of this review is to assess the diagnostic accuracy of different methodologies and estimate the prevalence of congenital uterine anomalies in women with infertility and recurrent miscarriage (RM). METHODS: Studies from 1950-2007 were identified through a computer MEDLINE search; all relevant references were further reviewed. RESULTS: The most accurate diagnostic procedures are combined hysteroscopy and laparoscopy, sonohysterography (SHG) and possibly three-dimensional ultrasound (3D US). Two-dimensional ultrasound (2D US) and hysterosalpingography (HSG) are less accurate and are thus inadequate for diagnostic purposes. Preliminary studies (n=24) suggest MRI is a relatively sensitive tool. A critical analysis of studies suggests that the prevalence of congenital uterine anomalies is ~6.7% [confidence interval (CI) 95%, 6.0 – 7.4] in the general population, ~7.3% (CI 95%, 6.7 – 7.9) in the infertile population and ~16.7% (CI 95%, 14.8 – 18.6) in the recurrent miscarriage (RM) population. The arcuate uterus is the commonest anomaly in the general and RM population. In contrast, the septate uterus is the commonest anomaly in the infertile population, suggesting a possible association. CONCLUSION: Women with RM have a high prevalence of congenital uterine anomalies and should be thoroughly investigated. HSG and/or 2D US can be used as an initial screening tool. Combined hysteroscopy and laparoscopy, SHG and 3D US can be used for a definitive diagnosis. The accuracy and practicality of magnetic resonance imaging (MRI) remains unclear

    Cancellous bone from porous Ti6A|4V by multiple coating technique

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    A highly porous T{i}6Al4V with interconnected porous structure has been developed in our previous study. By using a so-called “Multiple coating” technique, the porous T{i}6Al4V can be tailored to resemble cancellous bone in terms of porous structure and mechanical properties. A thin layer of T{i}6Al4V slurry was coated on the struts of base porous T{i}6Al4V to improve the pore structure. After two additional coating, pore sizes ranged from 100 μm to 700 μm, and the porosity was decreased from ∼90% to ∼ 75%, while the compressive strength was increased from 10.3 ± 3.3 MPa to 59.4 ± 20.3 MPa and the Young's modulus increased from 0.8 ± 0.3 GPa to 1.8 ± 0.3 GPa. The pore size and porosity are similar to that of cancellous bone, meanwhile the compressive strength is higher than that of cancellous bone, and the Young's modulus is between that of cancellous bone and cortical bone. Porosity, pore size and mechanical properties can be controlled by the parameters in such multiple coating processes. Therefore the porous T{i}6Al4V with the characteristics of cancellous bone is expected to be a promising biomaterial for biomedical applications

    Case-based reasoning approach to estimating the strength of sustainable concrete

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    Continuing from previous studies of sustainable concrete containing environmentally friendly materials and existing modeling approach to predicting concrete properties, this study developed an estimation methodology to predicting the strength of sustainable concrete using an advanced case-based reasoning approach. It was conducted in two steps: (i) establishment of a case database and (ii) development of an advanced case-based reasoning model. Through the experimental studies, a total of 144 observations for concrete compressive strength and tensile strength were established to develop the estimation model. As a result, the prediction accuracy of the A-CBR model (i.e., 95.214% for compressive strength and 92.448% for tensile strength) performed superior to other conventional methodologies (e.g., basic case-based reasoning and artificial neural network models). The developed methodology provides an alternative approach in predicting concrete properties and could be further extended to the future research area in durability of sustainable concrete

    Catharanthus mosaic virus: A potyvirus from a gymnosperm, Welwitschia mirabilis

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    A virus from a symptomatic plant of the gymnosperm Welwitschia mirabilis Hook. growing as an ornamental plant in a domestic garden in Western Australia was inoculated to a plant of Nicotiana benthamiana where it established a systemic infection. The complete genome sequence of 9636 nucleotides was determined using high-throughput and Sanger sequencing technologies. The genome sequence shared greatest identity (83% nucleotides and 91% amino acids) with available partial sequences of catharanthus mosaic virus, indicating that the new isolate belonged to that taxon. Analysis of the phylogeny of the complete virus sequence placed it in a monotypic group in the genus Potyvirus. This is the first record of a virus from W. mirabilis, the first complete genome sequence of catharanthus mosaic virus determined, and the first record from Australia. This finding illustrates the risk to natural and managed systems posed by the international trade in live plants and propagules, which enables viruses to establish in new regions and infect new hosts

    Dynamical coupled-channel study of K+ Lambda photoproduction

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    Results for the reaction gamma p --> K+ Lambda, studied within a constituent quark model and a dynamical coupled-channel approach, are presented and compared with recent data. Issues related to the search for missing baryon resonances are briefly discussed and the role played by a third S_{11} resonance is underlined.Comment: To appear in the proceedings of BARYONS 2004, Palaiseau, France, 25-29 Oct 200

    Forced oscillations in a hydrodynamical accretion disk and QPOs

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    This is the second of a series of papers aimed to look for an explanation on the generation of high frequency quasi-periodic oscillations (QPOs) in accretion disks around neutron star, black hole, and white dwarf binaries. The model is inspired by the general idea of a resonance mechanism in the accretion disk oscillations as was already pointed out by Abramowicz & Klu{\'z}niak (\cite{Abramowicz2001}). In a first paper (P\'etri \cite{Petri2005a}, paper I), we showed that a rotating misaligned magnetic field of a neutron star gives rise to some resonances close to the inner edge of the accretion disk. In this second paper, we suggest that this process does also exist for an asymmetry in the gravitational potential of the compact object. We prove that the same physics applies, at least in the linear stage of the response to the disturbance in the system. This kind of asymmetry is well suited for neutron stars or white dwarfs possessing an inhomogeneous interior allowing for a deviation from a perfectly spherically symmetric gravitational field. We show by a linear analysis that the disk initially in a cylindrically symmetric stationary state is subject to three kinds of resonances: a corotation resonance, a Lindblad resonance due to a driven force and a parametric sonance. The highest kHz QPOs are then interpreted as the orbital frequency of the disk at locations where the response to the resonances are maximal. It is also found that strong gravity is not required to excite the resonances.Comment: Accepte

    Evolution of community structure in the world trade web

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    In this note we study the bilateral merchandise trade flows between 186 countries over the 1948-2005 period using data from the International Monetary Fund. We use Pajek to identify network structure and behavior across thresholds and over time. In particular, we focus on the evolution of trade "islands" in the a world trade network in which countries are linked with directed edges weighted according to fraction of total dollars sent from one country to another. We find mixed evidence for globalization.Comment: To be submitted to APFA 6 Proceedings, 8 pages, 3 Figure

    Anthropogenic point-source and non-point-source nitrogen inputs into Huai River basin and their impacts on riverine ammonia–nitrogen flux

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    This study provides a new approach to estimate both anthropogenic non-point-source and point-source nitrogen (N) inputs to the landscape, and determines their impacts on riverine ammonia-nitrogen (AN) flux, providing a foundation for further exploration of anthropogenic effects on N pollution. Our study site is Huai River basin of China, a water–shed with one of the highest levels of N input in the world. Multi-year average (2003-2010) inputs of N to the watershed are 27 200 ± 1100 kg N km-2 yr-1. Non-point sources comprised about 98 % of total N input, and only 2 % of inputs are directly added to the aquatic ecosystem as point sources. Fertilizer application was the largest non-point source of new N to the Huai River basin (69 % of net anthropogenic N inputs), followed by atmospheric deposition (20 %), N fixation in croplands (7 %), and N content of imported food and feed (2 %). High N inputs showed impacts on riverine AN flux: fertilizer application, point-source N input, and atmospheric N deposition were proved as more direct sources to riverine AN flux. Modes of N delivery and losses associated with biological denitrification in rivers, water consumption, interception by dams may influence the extent of export of riverine AN flux from N sources. Our findings highlight the importance of anthropogenic N inputs from both point sources and non-point sources in heavily polluted watersheds, and provide some implications for AN prediction and management.This study was financially supported by the Key Research Program of the Chinese Academy of Sciences (no. KZZD-EW-10-02-3), the 13th Five-Year Plan of Chinese Academy of Sciences (no. YSW2013B02) and State Key Laboratory of Urban and Regional Ecology scientific project (no. SKLURE2013-1-05). The authors wish to express their gratitude to the China Scholarship Council (201408110138) for funding the visiting venture that generated this paper, and to Huai River Basin Water Resources Protection Bureau and Hydrologic Information Center of Huai River Commission for providing water quality and hydrological data
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