131 research outputs found

    Changing the diameter of 3D printed tissue engineering scaffolds made via melt electrospinning writing

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    Introduction. Due to the structural complexity of the natural tissues, a production of anatomically accurate three-dimensional (3D) structures is a major challenge in tissue engineering. Previously a technology termed melt electrospinning writing (MEW), produced 3D constructs out of filaments sized from 0.8 μm up to 140 μm [1-3]. Here the fiber diameter control during MEW printing was investigated. Methods: Poly (ε-caprolactone) (PCL) fibers were printed with a custom-built MEW device [4] at 73 ± 1 °C temperature, 8.5 kV voltage difference and 6 mm distance between the nozzle and the collector. The polymer flowrate was controlled by the air pressure variation between 0.5 and 4 bar. For the different fiber stretching, collector speed was varied from 300 to 10000 mm/min. Results. Fiber diameter could be changed from 2.02±0.57 μm to 49.93±2.61 μm (Figure 1A). Multi-modal 3D printed structures, produced within a single print are shown in Figure 1B-D. Figure 1B demonstrates a grid pattern of 3 μm fibers overlaid with 30 μm fibers. Figure 1C and 1D shows that multidiameter fibers can be precisely stacked and rotated around each other. As an example of a 3D-printed construct, a tapered frame for spheroid capture is shown in Figure 1E; due to the different diameters, this construct has a larger pore size at the top compared to the bottom. Please click Additional Files below to see the full abstract

    Raman spectroscopy - A powerful tool for in situ planetary science

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    This paper introduces Raman spectroscopy and discusses various scenarios where it might be applied to in situ planetary missions. We demonstrate the extensive capabilities of Raman spectroscopy for planetary investigations and argue that this technique is essential for future planetary missions

    Magnetotransport properties of iron microwires fabricated by focused electron beam induced autocatalytic growth

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    We have prepared iron microwires in a combination of focused electron beam induced deposition (FEBID) and autocatalytic growth from the iron pentacarbonyl, Fe(CO)5, precursor gas under UHV conditions. The electrical transport properties of the microwires were investigated and it was found that the temperature dependence of the longitudinal resistivity (rhoxx) shows a typical metallic behaviour with a room temperature value of about 88 micro{\Omega} cm. In order to investigate the magnetotransport properties we have measured the isothermal Hall-resistivities in the range between 4.2 K and 260 K. From these measurements positive values for the ordinary and the anomalous Hall coefficients were derived. The relation between anomalous Hall resistivity (rhoAN) and longitudinal resistivity is quadratic, rhoAN rho^2 xx, revealing an intrinsic origin of the anomalous Hall effect. Finally, at low temperature in the transversal geometry a negative magnetoresistance of about 0.2 % was measured

    The health of women and girls determines the health and well-being of our modern world: A White Paper From the International Council on Women's Health Issues

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    The International Council on Women's Health Issues (ICOWHI) is an international nonprofit association dedicated to the goal of promoting health, health care, and well-being of women and girls throughout the world through participation, empowerment, advocacy, education, and research. We are a multidisciplinary network of women's health providers, planners, and advocates from all over the globe. We constitute an international professional and lay network of those committed to improving women and girl's health and quality of life. This document provides a description of our organization mission, vision, and commitment to improving the health and well-being of women and girls globally

    Isoforms of U1-70k control subunit dynamics in the human spliceosomal U1 snRNP

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    Most human protein-encoding genes contain multiple exons that are spliced together, frequently in alternative arrangements, by the spliceosome. It is established that U1 snRNP is an essential component of the spliceosome, in human consisting of RNA and ten proteins, several of which are post- translationally modified and exist as multiple isoforms. Unresolved and challenging to investigate are the effects of these post translational modifications on the dynamics, interactions and stability of the particle. Using mass spectrometry we investigate the composition and dynamics of the native human U1 snRNP and compare native and recombinant complexes to isolate the effects of various subunits and isoforms on the overall stability. Our data reveal differential incorporation of four protein isoforms and dynamic interactions of subunits U1-A, U1-C and Sm-B/B’. Results also show that unstructured post- ranslationally modified C-terminal tails are responsible for the dynamics of Sm-B/B’ and U1-C and that their interactions with the Sm core are controlled by binding to different U1-70k isoforms and their phosphorylation status in vivo. These results therefore provide the important functional link between proteomics and structure as well as insight into the dynamic quaternary structure of the native U1 snRNP important for its function.This work was funded by: BBSRC (OVM), BBSRC and EPSRC (HH and NM), EU Prospects (HH), European Science Foundation (NM), the Royal Society (CVR), and fellowship from JSPS and HFSP (YM and DAPK respectively)

    Minerology and Crystallography of Some Itokawa Particles Returned by the Hayabusa Mission

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    JAXA Hayabusa mission success-fully returned particles of the asteroid Itokawa to the earth in 2010. The recovered particles were carefully studied by the preliminary examination (PE) team and the obtained results are providing significant and unique information about the formation and evolution of meteorite parent bodies [1-6]. These particles further revealed that their mineral compositions and oxygen isotopes are close to those of equilibrated LL chon-drites [1,2], which matches with the observation at the orbit [7]. After the PE, JAXA distributed the samples as international AO study and we received 4 new and 3 PE particles. The new samples may contain some exot-ic components that have not been found by the PE study, and are of special interest. We have performed a detailed mineralogical and crystallographic study on these particles and here report the results

    Persona-driven information security awareness.

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    Because human factors are a root cause of security breaches in many organisations, security awareness activities are often used to address problematic behaviours and improve security culture. Previous work has found that personas are useful for identifying audience needs and goals, when designing and implementing awareness campaigns. We present a six-step security awareness process both driven by and centred around the use of personas. This can be embedded into business-as-usual activities, with 90-day cycles of awareness themes. We evaluated this process by using it to devise a security awareness campaign for a digital agency. Our results suggest a persona-centred security awareness approach is adaptable to business constraints, and contributes towards addressing security risks

    A simple dummy liver assist device prolongs anhepatic survival in a porcine model of total hepatectomy by slight hypothermia

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    <p>Abstract</p> <p>Background</p> <p>Advances in intensive care support such as therapeutic hypothermia or new liver assist devices have been the mainstay of treatment attempting to bridge the gap from acute liver failure to liver transplantation, but the efficacy of the available devices in reducing mortality has been questioned. To address this issue, the present animal study was aimed to analyze the pure clinical effects of a simple extracorporeal dummy device in an anhepatic porcine model of acute liver failure.</p> <p>Methods</p> <p>Total hepatectomy was performed in ten female pigs followed by standardized intensive care support until death. Five animals (dummy group, n = 5) underwent additional cyclic connection to an extracorporeal dummy device which consisted of a plasma separation unit. The separated undetoxified plasma was completely returned to the pigs circulation without any plasma substitution or exchange in contrast to animals receiving intensive care support alone (control group, n = 5). All physiological parameters such as vital and ventilation parameters were monitored electronically; laboratory values and endotoxin levels were measured every 8 hours.</p> <p>Results</p> <p>Survival of the dummy device group was 74 ± 6 hours in contrast to 53 ± 5 hours of the control group which was statistically significant (p < 0.05). Body temperature 24 hours after hepatectomy was significantly lower (36.5 ± 0.5°C vs. 38.2 ± 0.7°C) in the dummy device group. Significant lower values were measured for blood lactate (1.9 ± 0.2 vs. 2.5 ± 0.5 mM/L) from 16 hours, creatinine (1.5 ± 0.2 vs. 2.0 ± 0.3 mg/dL) from 40 hours and ammonia (273 ± 122 vs. 1345 ± 700 μg/dL) from 48 hours after hepatectomy until death. A significant rise of endotoxin levels indicated the onset of sepsis at time of death in 60% (3/5) of the dummy device group animals surviving beyond 60 hours from hepatectomy.</p> <p>Conclusions</p> <p>Episodes of slight hypothermia induced by cyclic connection to the extracorporeal dummy device produced a significant survival benefit of more than 20 hours through organ protection and hemodynamic stabilisation. Animal studies which focus on a survival benefit generated by liver assist devices should especially address the aspect of slight transient hypothermia by extracorporeal cooling.</p
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