121 research outputs found

    Elastic and plastic stresses at weld sinkages and other discontinuities in pressure vessels

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    Mismatch and weld sinkage problems of pressure vessel geometric discontinuities studied in design graphs and test progra

    Elastic and plastic analysis of pressure vessel weld lands with mismatch

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    Elastic and plastic analysis of pressure vessel weld lands with mismatc

    New interfacial-gel copolymerization technique for steric GRIN polymer optical waveguides and lens arrays

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    Abstract: A synthetic polymeric lens was designed and fabricated based on a bio-inspired, "Age=5" human eye lens design by utilizing a nanolayered polymer film-based technique. The internal refractive index distribution of an anterior and posterior GRIN lens were characterized and confirmed against design by ”ATR-FTIR. 3D surface topography of the fabricated aspheric anterior and posterior lenses was measured by placido-cone topography and exhibited confirmation of the desired aspheric surface shape. Furthermore, the wavefronts of aspheric posterior GRIN and PMMA lenses were measured and simulated by interferometry and Zemax software, respectively. Their results show that the gradient index distribution reduces the overall wavefront error as compared a homogenous PMMA lens of an identical geometry. Finally, the anterior and posterior GRIN lenses were assembled into a bio-inspired GRIN human eye lens through which a clear imaging was possible

    Application of bone growth factors—the potential of different carrier systems

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    Aim The aim of the present review was to characterize the potential of different biomaterials as carriers for bone growth factors. Introduction Beyond mechanical and structural characteristics, one of the features that account for a potential carrier is the possibility to couple growth factor molecules to it. As simple adsorption of the growth factor to the carrier surface by soak loading produces a burst release of growth factors with rapid decrease of biological activity, the ability to accomplish controlled release of functional growth factor molecules is one of the crucial characteristics for an appropriate carrier material. Conclusion The variety of carrier materials requires different strategies to either couple growth factors to the material surface or to incorporate them into the carrier matrix. The present review outlines current technical approaches and discusses future trends in the use of carrier materials for bone growth factors

    Anti-citrullinated protein antibodies cause arthritis by cross-reactivity to joint cartilage

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    Today, it is known that autoimmune diseases start a long time before clinical symptoms appear. Anti-citrullinated protein antibodies (ACPAs) appear many years before the clinical onset of rheumatoid arthritis (RA). However, it is still unclear if and how ACPAs are arthritogenic. To better understand the molecular basis of pathogenicity of ACPAs, we investigated autoantibodies reactive against the C1 epitope of collagen type II (CII) and its citrullinated variants. We found that these antibodies are commonly occurring in RA. A mAb (ACC1) against citrullinated C1 was found to cross-react with several noncitrullinated epitopes on native CII, causing proteoglycan depletion of cartilage and severe arthritis in mice. Structural studies by X-ray crystallography showed that such recognition is governed by a shared structural motif "RG-TG" within all the epitopes, including electrostatic potential-controlled citrulline specificity. Overall, we have demonstrated a molecular mechanism that explains how ACPAs trigger arthritis

    Development of the rhopalial nervous system in Aurelia sp.1 (Cnidaria, Scyphozoa)

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    We examined the development of the nervous system in the rhopalium, a medusa-specific sensory structure, in Aurelia sp.1 (Cnidaria, Scyphozoa) using confocal microscopy. The rhopalial nervous system appears primarily ectodermal and contains neurons immunoreactive to antibodies against tyrosinated tubulin, taurine, GLWamide, and FMRFamide. The rhopalial nervous system develops in an ordered manner: the presumptive gravity-sensing organ, consisting of the lithocyst and the touch plate, differentiates first; the “marginal center,” which controls swimming activity, second; and finally, the ocelli, the presumptive photoreceptors. At least seven bilaterally arranged neuronal clusters consisting of sensory and ganglion cells and their neuronal processes became evident in the rhopalium during metamorphosis to the medusa stage. Our analysis provides an anatomical framework for future gene expression and experimental studies of development and functions of scyphozoan rhopalia

    Homotopic glial regulation of striatal projection neuron differentiation

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    We have studied the differentiation of striatal projection neurons in co-culture with expanded glia from different regions of the embryonic mouse telencephalon. Our results show that when striatal progenitors are cultured on glia derived from the same region as they originate (i.e. the lateral ganglionic eminence), the neurons formed exhibit long processes. This is not the case when the cells are co-cultured with glia derived from the adjacent telencephalic region, the medial ganglionic eminence. Moreover, expression of the striatal projection neuron marker, dopamine- and cAMP-regulated phosphoprotein (DARPP-32) was significantly enhanced in neurons cultured on the homotopic glia. Thus, glial cultures derived from the lateral ganglionic eminence positively regulate the differentiation of striatal projection neurons in vitro
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