1,463 research outputs found

    Stimuli Responsive Shape Memory Microarchitectures

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    Shape memory polymers (SMPs) respond to heat by generating programmable movement in devices that require substantial deformation and operate at transient temperatures, including stents and embolization coils. To enable their use in small‐scale applications like retinal vasculature stenting, shape transformations must occur in SMPs with complex 3D geometries with nanoscale features. This work describes the synthesis and sculpting of a benzyl methacrylate‐based SMP into 3D structures with <800 nm characteristic critical dimensions via two photon lithography. Dynamic nanomechanical analysis of 8 ”m‐diameter cylindrical pillars reveal the initiation of this SMP's glass transition at 60 °C. Shape memory programming of the characterized pillars as well as complex 3D architectures, including flowers with 500 nm thick petals and cubic lattices with 2.5 ”m unit cells and overall dimensions of 4.5 ”m × 4.5 ”m × 10 ”m, demonstrate an 86 +/− 4% characteristic shape recovery ratio. These results reveal a pathway toward SMP devices with nanoscale features and arbitrary 3D geometries changing shape in response to temperature

    Inclusive Recovery in US Cities

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    Some cities have harnessed economic recoveries to improve on inclusion, or the opportunity for all residents—particularly historically excluded populations—to benefit from and contribute to economic prosperity. In this report, we conduct the first empirical analysis of how economic health and inclusion interact in US cities over several decades. We report on trends in economic health and inclusion across many cities and within a smaller subset of cities that have experienced an economic recovery. To better understand whether and how an economic recovery can support inclusive outcomes, we delve deeper into four cities that improved on inclusion measures during their recovery. Through discussions with individuals, an in-person convening, and a review of literature, we identify key lessons and common building blocks that can support progress on inclusion during a city's economic recovery

    Access routes and reported decision criteria for lumbar epidural drug injections: a systematic literature review

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    Purpose: To review lumbar epidural drug injection routes in relation to current practice and the reported criteria used for selecting a given approach. Material and methods: This was a HIPPA-compliant study. Employing a systematic search strategy, the MEDLINE and EMBASE databank as well as the Cochrane Library were searched for studies on epidural drug injections. The following data were noted: access route, level of injection, use of image guidance, and types and doses of injected drugs. Justifications for the use of a particular route were also noted. Data were presented using descriptive statistics. Results: A total of 1,211 scientific studies were identified, of which 91 were finally included (7.5%). The interlaminar access route was used in 44 of 91 studies (48.4%), the transforaminal in 37 of 91 studies (40.7%), and the caudal pathway in 26 of 91 studies (28.6%). The caudal pathway was favored in the older studies whereas the transforaminal route was favored in recent studies. Decision criteria related to correct needle placement, concentration of injected drug at lesion site, technical complexity, costs, and potential complications. Injection was usually performed on the level of the lesion using local anesthetics (71 of 91 studies, 78.0%), steroids (all studies) and image guidance (71 of 91 studies, 78%). Conclusions: The most commonly used access routes for epidural drug injection are the interlaminar and transforaminal pathways at the level of the pathology. Transforaminal routes are being performed with increasing frequency in recent year

    Symptoms Relevant to Surveillance for Ovarian Cancer

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    To examine how frequently and confidently healthy women report symptoms during surveillance for ovarian cancer. A symptoms questionnaire was administered to 24,526 women over multiple visits accounting for 70,734 reports. A query of reported confidence was included as a confidence score (CS). Chi square, McNemars test, ANOVA and multivariate analyses were performed. 17,623 women completed the symptoms questionnaire more than one time and \u3e 9500 women completed it more than one four times for \u3e 43,000 serially completed questionnaires. Reporting ovarian cancer symptoms was ~245 higher than ovarian cancer incidence. The positive predictive value (0.073%) for identifying ovarian cancer based on symptoms alone would predict one malignancy for 1368 cases taken to surgery due to reported symptoms. Confidence on the first questionnaire (83.3%) decreased to 74% when more than five questionnaires were completed. Age-related decreases in confidence were significant (p \u3c 0.0001). Women reporting at least one symptom expressed more confidence (41,984/52,379 = 80.2%) than women reporting no symptoms (11,882/18,355 = 64.7%), p \u3c 0.0001. Confidence was unrelated to history of hormone replacement therapy or abnormal ultrasound findings (p = 0.30 and 0.89). The frequency of symptoms relevant to ovarian cancer was much higher than the occurrence of ovarian cancer. Approximately 80.1% of women expressed confidence in what they reported

    Differential expression of paralog RNA binding proteins establishes a dynamic splicing program required for normal cerebral cortex development

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    : sam68 and SLM2 are paralog RNA binding proteins (RBPs) expressed in the cerebral cortex and display similar splicing activities. however, their relative functions during cortical development are unknown. we found that these RBPs exhibit an opposite expression pattern during development. sam68 expression declines postnatally while SLM2 increases after birth, and this developmental pattern is reinforced by hierarchical control of sam68 expression by SLM2. analysis of sam68:Slm2 double knockout (Sam68:Slm2dko) mice revealed hundreds of exons that respond to joint depletion of these proteins. moreover, parallel analysis of single and double knockout cortices indicated that exons regulated mainly by SLM2 are characterized by a dynamic splicing pattern during development, whereas sam68-dependent exons are spliced at relatively constant rates. dynamic splicing of SLM2-sensitive exons is completely suppressed in the sam68:Slm2dko developing cortex. sam68:Slm2dko mice die perinatally with defects in neurogenesis and in neuronal differentiation, and develop a hydrocephalus, consistent with splicing alterations in genes related to these biological processes. thus, our study reveals that developmental control of separate sam68 and Slm2 paralog genes encoding homologous RBPs enables the orchestration of a dynamic splicing program needed for brain development and viability, while ensuring a robust redundant mechanism that supports proper cortical development

    The Future of Heliophysics Research through Targeted use of Constellations

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    This white paper seeks to outline the benefits and challenges of constellations, ranging from the Heliophysics System Observatory, to constellations consisting of a small number of spacecraft, to large-number constellations. In moving toward this constellation era, investments are required by our sponsors to best enable our continued scientific advancement in Solar and Space Physics

    A technique to train new oculomotor behavior in patients with central macular scotomas during reading related tasks using scanning laser ophthalmoscopy: immediate functional benefits and gains retention

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    BACKGROUND: Reading with a central scotoma involves the use of preferred retinal loci (PRLs) that enable both letter resolution and global viewing of word. Spontaneously developed PRLs however often privilege spatial resolution and, as a result, visual span is commonly limited by the position of the scotoma. In this study we designed and performed the pilot trial of a training procedure aimed at modifying oculomotor behavior in subjects with central field loss. We use an additional fixation point which, when combined with the initial PRL, allows the fulfillment of both letter resolution and global viewing of words. METHODS: The training procedure comprises ten training sessions conducted with the scanning laser ophthalmoscope (SLO). Subjects have to read single letters and isolated words varying in length, by combining the use of their initial PRL with the one of an examiner's selected trained retinal locus (TRL). We enrolled five subjects to test for the feasibility of the training technique. They showed stable maculopathy and persisting major reading difficulties despite previous orthoptic rehabilitation. We evaluated ETDRS visual acuity, threshold character size for single letters and isolated words, accuracy for paragraphed text reading and reading strategies before, immediately after SLO training, and three months later. RESULTS: Training the use of multiple PRLs in patients with central field loss is feasible and contributes to adapt oculomotor strategies during reading related tasks. Immediately after SLO training subjects used in combination with their initial PRL the examiner's selected TRL and other newly self-selected PRLs. Training gains were also reflected in ETDRS acuity, threshold character size for words of different lengths and in paragraphed text reading. Interestingly, subjects benefited variously from the training procedure and gains were retained differently as a function of word length. CONCLUSION: We designed a new procedure for training patients with central field loss using scanning laser ophthalmoscopy. Our initial results on the acquisition of newly self-selected PRLs and the development of new oculomotor behaviors suggest that the procedure aiming primarily at developing an examiner's selected TRL might have initiated a more global functional adaptation process

    Hundreds of variants clustered in genomic loci and biological pathways affect human height

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    Most common human traits and diseases have a polygenic pattern of inheritance: DNA sequence variants at many genetic loci influence the phenotype. Genome-wide association (GWA) studies have identified more than 600 variants associated with human traits, but these typically explain small fractions of phenotypic variation, raising questions about the use of further studies. Here, using 183,727 individuals, we show that hundreds of genetic variants, in at least 180 loci, influence adult height, a highly heritable and classic polygenic trait. The large number of loci reveals patterns with important implications for genetic studies of common human diseases and traits. First, the 180 loci are not random, but instead are enriched for genes that are connected in biological pathways (P = 0.016) and that underlie skeletal growth defects (P < 0.001). Second, the likely causal gene is often located near the most strongly associated variant: in 13 of 21 loci containing a known skeletal growth gene, that gene was closest to the associated variant. Third, at least 19 loci have multiple independently associated variants, suggesting that allelic heterogeneity is a frequent feature of polygenic traits, that comprehensive explorations of already-discovered loci should discover additional variants and that an appreciable fraction of associated loci may have been identified. Fourth, associated variants are enriched for likely functional effects on genes, being over-represented among variants that alter amino-acid structure of proteins and expression levels of nearby genes. Our data explain approximately 10% of the phenotypic variation in height, and we estimate that unidentified common variants of similar effect sizes would increase this figure to approximately 16% of phenotypic variation (approximately 20% of heritable variation). Although additional approaches are needed to dissect the genetic architecture of polygenic human traits fully, our findings indicate that GWA studies can identify large numbers of loci that implicate biologically relevant genes and pathways.
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