694 research outputs found

    Displacing and Disrupting: A Dialogue on Hmong Studies and Asian American Studies

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    This article summarizes a roundtable discussion of scholars that took place at the Association for Asian American Studies Conference in San Francisco, 2014. Hailing from various academic disciplines, the participants explored the relationship between the emerging field of Hmong/Hmong American Studies and Asian American Studies. Questions of interest included: In what ways has Asian American Studies informed Hmong/Hmong American Studies, or failed to do so? In what ways does Hmong/Hmong American Studies enrich/challenge Asian American Studies? What are the tensions between these two fields and other related fields? How do/should the new programs in Hmong/Hmong American Studies relate to the existing Asian American Studies programs regarding curriculum, activism and/or resource allocation

    Peptide:glycosaminoglycan hybrid hydrogels as an injectable intervention for spinal disc degeneration

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    Degeneration of the spinal discs is a major cause of back pain. During the degeneration process, there is a loss of glycosaminoglycans (GAGs) from the proteoglycan-rich gel in the disc’s nucleus, which adversely alters biomechanical performance. Current surgical treatments for back pain are highly invasive and have low success rates; there is an urgent need for minimally-invasive approaches that restore the physiological mechanics of the spine. Here we present an injectable peptide:GAG hydrogel that rapidly self-assembles in situ and restores the mechanics of denucleated intervertebral discs. It forms a gel with comparable mechanical properties to the native tissue within seconds to minutes depending on the peptide chosen. Unlike other biomaterials that have been proposed for this purpose, these hybrid hydrogels can be injected through a very narrow 25 G gauge needle, minimising damage to the surrounding soft tissue, and they mimic the ability of the natural tissue to draw in water by incorporating GAGs. Furthermore, the GAGs enhance the gelation kinetics and thermodynamic stability of peptide hydrogels, significantly reducing effusion of injected material from the intervertebral disc (GAG leakage of 8 ± 3% after 24 hrs when peptide present, compared to 39 ± 3% when no peptide present). In an ex vivo model, we demonstrate that the hydrogels can restore the compressive stiffness of denucleated bovine intervertebral discs. Compellingly, this novel biomaterial has the potential to transform the clinical treatment of back pain by resolving current surgical challenges, thus improving patient quality of life

    Quality care and safety know no borders

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    The public, governmental agencies, and payers expect medical professional organisations to develop practice guidelines and technical standards. The American College of Radiology proactively addresses these topics as well as other quality and safety interests including appropriateness criteria and accreditation. The College is also actively involved in development of a national radiology data base to collect data regarding quality and safety metrics in multiple areas. In addition, the College has developed RADPEER™, a simple, cost-effective process that allows peer review to be performed during the routine interpretation of current images. This paper discusses the efforts of the ACR in all of these areas

    MATERNAL PREVALENCE OF TOXOPLASMA ANTIBODY BASED ON ANONYMOUS NEONATAL SEROSURVEY - A GEOGRAPHICAL ANALYSIS

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    A total of 12902 neonatal samples collected on absorbent paper for routine metabolic screening were tested anonymously for antibodies to toxoplasma. Seroprevalence varied from 19.5% in inner London, to 11.6% in suburban London, and 7.6% in non-metropolitan districts. Much of this variation appeared to be associated with the proportions of livebirths in each district to women born outside the UK. However, additional geographical variation remained and seroprevalence in UK-born women was estimated to be 12.7% in inner London. 7.5% in suburban London, and 5.5% in non-metropolitan areas. These estimates are considerably lower than any previously reported in antenatal sera in the UK. The wide geographical variation highlights a need for further research to determine the relative importance of different routes of transmission

    Hydrodynamic Mixing Tunes the Stiffness of Proteoglycan‐Mimicking Physical Hydrogels

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    Self‐assembling hydrogels are promising materials for regenerative medicine and tissue engineering. However, designing hydrogels that replicate the 3–4 order of magnitude variation in soft tissue mechanics remains a major challenge. Here hybrid hydrogels are investigated formed from short self‐assembling β‐fibril peptides, and the glycosaminoglycan chondroitin sulfate (CS), chosen to replicate physical aspects of proteoglycans, specifically natural aggrecan, which provides structural mechanics to soft tissues. Varying the peptide:CS compositional ratio (1:2, 1:10, or 1:20) can tune the mechanics of the gel by one to two orders of magnitude. In addition, it is demonstrated that at any fixed composition, the gel shear modulus can be tuned over approximately two orders of magnitude through varying the initial vortex mixing time. This tuneability arises due to changes in the mesoscale structure of the gel network (fibril width, length, and connectivity), giving rise to both shear‐thickening and shear‐thinning behavior. The resulting hydrogels range in shear elastic moduli from 0.14 to 220 kPa, mimicking the mechanical variability in a range of soft tissues. The high degree of discrete tuneability of composition and mechanics in these hydrogels makes them particularly promising for matching the chemical and mechanical requirements of different applications in tissue engineering and regenerative medicine

    Evaluation of injectable nucleus augmentation materials for the treatment of intervertebral disc degeneration

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    Back pain affects a person's health and mobility as well as being associated with large health and social costs. Lower back pain is frequently caused by degeneration of the intervertebral disc. Current operative and non-operative treatments are often ineffective and expensive. Nucleus augmentation is designed to be a minimally invasive method of restoring the disc to its native healthy state by restoring the disc height, and mechanical and/or biological properties. The majority of the candidate materials for nucleus augmentation are injectable hydrogels. In this review, we examine the materials that are currently under investigation for nucleus augmentation, and compare their ability to meet the design requirements for this application. Specifically, the delivery of the material into the disc, the mechanical properties of the material and the biological compatibility are examined. Recommendations for future testing are also made

    Integrated Ecosystem Assessment: Lake Ontario Water Management

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    BACKGROUND: Ecosystem management requires organizing, synthesizing, and projecting information at a large scale while simultaneously addressing public interests, dynamic ecological properties, and a continuum of physicochemical conditions. We compared the impacts of seven water level management plans for Lake Ontario on a set of environmental attributes of public relevance. METHODOLOGY AND FINDINGS: Our assessment method was developed with a set of established impact assessment tools (checklists, classifications, matrices, simulations, representative taxa, and performance relations) and the concept of archetypal geomorphic shoreline classes. We considered each environmental attribute and shoreline class in its typical and essential form and predicted how water level change would interact with defining properties. The analysis indicated that about half the shoreline of Lake Ontario is potentially sensitive to water level change with a small portion being highly sensitive. The current water management plan may be best for maintaining the environmental resources. In contrast, a natural water regime plan designed for greatest environmental benefits most often had adverse impacts, impacted most shoreline classes, and the largest portion of the lake coast. Plans that balanced multiple objectives and avoided hydrologic extremes were found to be similar relative to the environment, low on adverse impacts, and had many minor impacts across many shoreline classes. SIGNIFICANCE: The Lake Ontario ecosystem assessment provided information that can inform decisions about water management and the environment. No approach and set of methods will perfectly and unarguably accomplish integrated ecosystem assessment. For managing water levels in Lake Ontario, we found that there are no uniformly good and bad options for environmental conservation. The scientific challenge was selecting a set of tools and practices to present broad, relevant, unbiased, and accessible information to guide decision-making on a set of management options

    Improved pregnancy rate with administration of hCG after intrauterine insemination: a pilot study

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    <p>Abstract</p> <p>Background</p> <p>In natural cycles, women conceive when intercourse takes place during a six-day period ending on the day of ovulation. The current practice in intrauterine insemination (IUI) cycles is to perform the IUI 24-36 hours after the hCG administration, when the ovulation is already imminent. In this study hCG was administered after the IUI, which more closely resembles the fertilisation process in natural cycles.</p> <p>Methods</p> <p>All the IUIs performed since the beginning of 2007 were analysed retrospectively. Our standard protocol has been to perform the IUI 24-32 hours after hCG administration. From the end of 2008, we started to inject hCG after the IUI at random. The main outcome measure was the result of a urinary pregnancy test. Generalized Estimating Equations (GEE) was used to identify independent factors affecting the cycle outcome.</p> <p>Results</p> <p>The analysis included 228 cycles with hCG administered before and 104 cycles hCG administered after the IUI. The pregnancy rates were 10.9% and 19.6% (P = 0.040), respectively. Independent factors (OR, 95% CI) affecting the cycle outcome were sperm count (2.65, 1.20-5.81), number of follicles > 16 mm at IUI (2.01, 1.07-3.81) and the time of hCG administration (2.21, 1.16-4.19).</p> <p>Conclusion</p> <p>Improved pregnancy rate was observed with administration of hCG after IUI.</p

    Reexamining the effects of gestational age, fetal growth, and maternal smoking on neonatal mortality

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    BACKGROUND: Low birth weight (<2,500 g) is a strong predictor of infant mortality. Yet low birth weight, in isolation, is uninformative since it is comprised of two intertwined components: preterm delivery and reduced fetal growth. Through nonparametric logistic regression models, we examine the effects of gestational age, fetal growth, and maternal smoking on neonatal mortality. METHODS: We derived data on over 10 million singleton live births delivered at ≥ 24 weeks from the 1998–2000 U.S. natality data files. Nonparametric multivariable logistic regression based on generalized additive models was used to examine neonatal mortality (deaths within the first 28 days) in relation to fetal growth (gestational age-specific standardized birth weight), gestational age, and number of cigarettes smoked per day. All analyses were further adjusted for the confounding effects due to maternal age and gravidity. RESULTS: The relationship between standardized birth weight and neonatal mortality is nonlinear; mortality is high at low z-score birth weights, drops precipitously with increasing z-score birth weight, and begins to flatten for heavier infants. Gestational age is also strongly associated with mortality, with patterns similar to those of z-score birth weight. Although the direct effect of smoking on neonatal mortality is weak, its effects (on mortality) appear to be largely mediated through reduced fetal growth and, to a lesser extent, through shortened gestation. In fact, the association between smoking and reduced fetal growth gets stronger as pregnancies approach term. CONCLUSIONS: Our study provides important insights regarding the combined effects of fetal growth, gestational age, and smoking on neonatal mortality. The findings suggest that the effect of maternal smoking on neonatal mortality is largely mediated through reduced fetal growth
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