4,524 research outputs found
Potential technology directions of molecular metals
Journal ArticleIn the past decade, anisotropic molecular conductors have been found which possess unusual electrical, optical, magnetic, and in some cases mechanical properties. Exploiting these properties for specific devices is inevitable, and a number of diverse applications of molecular metals have been reported over the past few years
Development and test of advanced composite components. Center Directors discretionary fund program
This report describes the design, analysis, fabrication, and test of a complex bathtub fitting. Graphite fibers in an epoxy matrix were utilized in manufacturing of 11 components representing four different design and layup concepts. Design allowables were developed for use in the final stress analysis. Strain gage measurements were taken throughout the static load test and correlation of test and analysis data were performed, yielding good understanding of the material behavior and instrumentation requirements for future applications
Niche evolution reveals disparate signatures of speciation in the âgreat speciatorâ (whiteâeyes, Aves: Zosterops )
ACKNOWLEDGEMENTS J.O.E. and L.L. coordinated and secured project funding with the support from J.S.C.; we thank AT Peterson and CH Graham and two reviewers for critical feedback on earlier stages of the manuscript. The project was funded by the Research Foundation â Flanders (FWO; 1527918N & G042318N). J.O.E. received additional funds by an FWO Postdoctoral Fellowship (12G4317N). The authors declare no conflict of interest. No permits were needed to conduct the re- search presented here. DATA AVAILABILITY STATEMENT All data are available from open source platforms. Raw GBIF.org occurrence data used for this work (as accessed on 21st October 2016) can be accessed through GBIF Occurrence Download http://doi.org/10.15468/dl.erwqs6. We have deposited the prepared data used for this work on FigShare accessible through https://doi.org/10.6084/m9.figshare.13042031.v1 as well as R scripts for data analysis in a GitHub repository accessible through https://github.com/JOEngler/ZostiNicheEvol.Peer reviewedPublisher PD
Absolute lymphocyte and neutrophil counts in neonatal ischemic brain injury
Objectives: This study aimed to identify differences in absolute neutrophils, lymphocytes, and neutrophil-to-lymphocyte ratio between neonates with two forms of ischemic brain injury, hypoxic-ischemic encephalopathy, and acute ischemic stroke, compared to controls. We also aimed to determine whether this neutrophil/lymphocyte response pattern is associated with disease severity or is a consequence of the effects of total-body cooling, an approved treatment for moderate-to-severe hypoxic-ischemic encephalopathy. Methods: A retrospective chart review of 101 neonates with hypoxic-ischemic encephalopathy+total-body cooling (n=26), hypoxic-ischemic encephalopathy (n=12), acute ischemic stroke (n=15), and transient tachypnea of the newborn (n=48) was conducted; transient tachypnea of the newborn neonates were used as the control group. Absolute neutrophil count and absolute lymphocyte count at three time-intervals (0â12, 12â36, and 36â60 h after birth) were collected, and neutrophilto-lymphocyte ratio was calculated. Results: Hypoxic-ischemic encephalopathy+total-body cooling neonates demonstrated significant time-interval-dependent changes in absolute lymphocyte count and neutrophil-to-lymphocyte ratio levels compared to transient tachypnea of the newborn and acute ischemic stroke patients. Pooled analysis of absolute lymphocyte count for neonates with acute ischemic stroke and hypoxic-ischemic encephalopathy (not hypoxic-ischemic encephalopathy+total-body cooling) revealed that absolute lymphocyte count changes occurring at 0â12h are likely due to disease progression, rather than total-body cooling treatment. Conclusion: These data suggest that the neutrophil/lymphocyte response is modulated following neonatal ischemic brain injury, representing a possible target for therapeutic intervention. However, initial severity of hypoxic-ischemic encephalopathy among these patients could also account for the observed changes in the immune response to injury. Thus, additional work to clarify the contributions of cooling therapy and disease severity to neutrophil/lymphocyte response following hypoxicischemic encephalopathy in neonates is warranted
Power-Law Rheology of Isolated Nuclei with Deformation Mapping of Nuclear Substructures
Force-induced changes in genome expression as well as remodeling of nuclear architecture in development and disease motivate a deeper understanding of nuclear mechanics. Chromatin and green fluorescent protein-lamin B dynamics were visualized in a micropipette aspiration of isolated nuclei, and both were shown to contribute to viscoelastic properties of the somatic cell nucleus. Reversible swelling by almost 200% in volume, with changes in salt, demonstrates the resilience and large dilational capacity of the nuclear envelope, nucleoli, and chromatin. Swelling also proves an effective way to separate the mechanical contributions of nuclear elements. In unswollen nuclei, chromatin is a primary force-bearing element, whereas swollen nuclei are an order of magnitude softer, with the lamina sustaining much of the load. In both cases, nuclear deformability increases with time, scaling as a power lawâthus lacking any characteristic timescaleâwhen nuclei are either aspirated or indented by atomic force microscopy. The nucleus is stiff and resists distortion at short times, but it softens and deforms more readily at longer times. Such results indicate an essentially infinite spectrum of timescales for structural reorganization, with implications for regulating genome expression kinetics
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IL-17A produced by αÎČ T cells drives airway hyper-responsiveness in mice and enhances mouse and human airway smooth muscle contraction.
Emerging evidence suggests that the T helper 17 (T(H)17) subset of αÎČ T cells contributes to the development of allergic asthma. In this study, we found that mice lacking the αvÎČ8 integrin on dendritic cells did not generate T(H)17 cells in the lung and were protected from airway hyper-responsiveness in response to house dust mite and ovalbumin sensitization and challenge. Because loss of T(H)17 cells inhibited airway narrowing without any obvious effects on airway inflammation or epithelial morphology, we examined the direct effects of T(H)17 cytokines on mouse and human airway smooth muscle function. Interleukin-17A (IL-17A), but not IL-17F or IL-22, enhanced contractile force generation of airway smooth muscle through an IL-17 receptor A (IL-17RA)-IL-17RC, nuclear factor Îș light-chain enhancer of activated B cells (NF-ÎșB)-ras homolog gene family, member A (RhoA)-Rho-associated coiled-coil containing protein kinase 2 (ROCK2) signaling cascade. Mice lacking integrin αvÎČ8 on dendritic cells showed impaired activation of this pathway after ovalbumin sensitization and challenge, and the diminished contraction of the tracheal rings in these mice was reversed by IL-17A. These data indicate that the IL-17A produced by T(H)17 cells contributes to allergen-induced airway hyper-responsiveness through direct effects on airway smooth muscle
Surface probe measurements of the elasticity of sectioned tissue, thin gels and polyelectrolyte multilayer films : correlations between substrate stiffness and cell adhesion
Surface probe measurements of the elasticity of thin-film matrices as well as biological samples prove generally important to understanding cell attachment across such systems. To illustrate this, sectioned arteries were probed by Atomic Force Microscopy (AFM) within the smooth muscle cell (SMC)-rich medial layer, yielding an apparent Youngâs modulus Emedia ~ 5-8 kPa. Polyacrylamide gels with Egel spanning several-fold above and below this range were then cast 5-70 ÎŒm thick and coated with collagen: SMC spreading shows a hyperbolic dependence in projected cell area versus Egel. The modulus that gives half-max spreading is E1/2-spread ~ 8-10 kPa, proving remarkably close to Emedia. More complex, layer-by-layer micro-films of poly(L-lysine)/hyaluronic acid were also tested and show equivalent trends of increased SMC spreading with increased stiffness. Adhesive spreading of cells thus seems to correlate broadly with the effective stiffness of synthetic materials and tissues
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