100 research outputs found
Validity of a Novel Digitally Enhanced Skills Training Station for Freehand Distal Interlocking
Background and Objectives: Freehand distal interlocking of intramedullary nails is technically
demanding and prone to handling issues. It requires precise placement of a screw through the nail
under fluoroscopy guidance and can result in a time consuming and radiation expensive procedure.
Dedicated training could help overcome these problems. The aim of this study was to assess construct
and face validity of new Digitally Enhanced Hands-On Surgical Training (DEHST) concept and
device for training of distal interlocking of intramedullary nails. Materials and Methods: Twenty-nine
novices and twenty-four expert surgeons performed interlocking on a DEHST device. Construct
validity was evaluated by comparing captured performance metricsânumber of X-rays, nail hole
roundness, drill tip position and drill hole accuracyâbetween experts and novices. Face validity was
evaluated with a questionnaire concerning training potential and quality of simulated reality using
a 7-point Likert scale. Results: Face validity: mean realism of the training device was rated 6.3 (range
4â7). Training potential and need for distal interlocking training were both rated with a mean of
6.5 (range 5â7), with no significant differences between experts and novices, p 0.234. All participants
(100%) stated that the device is useful for procedural training of distal nail interlocking, 96% wanted
to have it at their institution and 98% would recommend it to colleagues. Construct validity: total
number of X-rays was significantly higher for novices (20.9 6.4 versus 15.5 5.3, p = 0.003). Success
rate (ratio of hit and miss attempts) was significantly higher for experts (novices hit: n = 15; 55.6%;
experts hit: n = 19; 83%, p = 0.040). Conclusion: The evaluated training device for distal interlocking of
intramedullary nails yielded high scores in terms of training capability and realism. Furthermore,
construct validity was proven by reliably discriminating between experts and novices. Participants
indicate high further training potential as the device may be easily adapted to other surgical tasks
Validity of a Novel Digitally Enhanced Skills Training Station for Freehand Distal Interlocking.
Background and Objectives: Freehand distal interlocking of intramedullary nails is technically demanding and prone to handling issues. It requires precise placement of a screw through the nail under fluoroscopy guidance and can result in a time consuming and radiation expensive procedure. Dedicated training could help overcome these problems. The aim of this study was to assess construct and face validity of new Digitally Enhanced Hands-On Surgical Training (DEHST) concept and device for training of distal interlocking of intramedullary nails. Materials and Methods: Twenty-nine novices and twenty-four expert surgeons performed interlocking on a DEHST device. Construct validity was evaluated by comparing captured performance metrics-number of X-rays, nail hole roundness, drill tip position and drill hole accuracy-between experts and novices. Face validity was evaluated with a questionnaire concerning training potential and quality of simulated reality using a 7-point Likert scale. Results: Face validity: mean realism of the training device was rated 6.3 (range 4-7). Training potential and need for distal interlocking training were both rated with a mean of 6.5 (range 5-7), with no significant differences between experts and novices, p ℠0.234. All participants (100%) stated that the device is useful for procedural training of distal nail interlocking, 96% wanted to have it at their institution and 98% would recommend it to colleagues. Construct validity: total number of X-rays was significantly higher for novices (20.9 ± 6.4 versus 15.5 ± 5.3, p = 0.003). Success rate (ratio of hit and miss attempts) was significantly higher for experts (novices hit: n = 15; 55.6%; experts hit: n = 19; 83%, p = 0.040). Conclusion: The evaluated training device for distal interlocking of intramedullary nails yielded high scores in terms of training capability and realism. Furthermore, construct validity was proven by reliably discriminating between experts and novices. Participants indicate high further training potential as the device may be easily adapted to other surgical tasks
Effective Space Confinement by Inverse Miniemulsion for the Controlled Synthesis of Undoped and Eu -Doped Calcium Molybdate Nanophosphors: A Systematic Comparison with Batch Synthesis
The possibility to precisely control reaction outcomes for pursuing materials with well-defined features is a main endeavor in the development of inorganic materials. Confining reactions within a confined space, such as nanoreactors, is an extremely promising methodology which allows to ensure control over the final properties of the material. An effective room temperature inverse miniemulsion approach for the controlled synthesis of undoped and Eu3+-doped calcium molybdate crystalline nanophosphors was developed. The advantages and the efficiency of confined space in terms of controlling nanoparticle features like size, shape, and functional properties are highlighted by systematically comparing miniemulsion products with calcium molybdate particles obtained without confinement from a typical batch synthesis. A relevant beneficial impact of space confinement by miniemulsion nanodroplets is observed on the control of size and shape of the final nanoparticles, resulting in 12 nm spherical nanoparticles with a narrow size distribution, as compared to the 58 nm irregularly shaped and aggregated particles from the batch approach (assessed by TEM analysis). Further considerable effects of the confined space for the miniemulsion samples are found on the doping effectiveness, leading to a more homogeneous distribution of the Eu ions into the molybdate host matrix, without segregation (assessed by PXRD, XAS, and ICP-MS). These findings are finally related to the photoluminescence properties, which are evidenced to be closely dependent on the Eu content for the miniemulsion samples, as an increase of the relative intensity of the direct fâf excitation and a shortening of the lifetime (from 0.901 ms for 1 at. % to 0.625 ms for 7 at. % samples) with increasing Eu content are observed, whereas no relationship between these parameters and the Eu content is evidenced for the batch samples. All these results are ascribed to the uniform and controlled crystallization occurring inside each miniemulsion nanodroplet, as opposed to the less controlled nucleation and growth for a classic nonconfined approach
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Self-Assembly of Polymer-Modified FePt Magnetic Nanoparticles and Block Copolymers
The fabrication of nanocomposites containing magnetic nanoparticles is gaining interest as a model for application in small electronic devices. The self-assembly of block copolymers (BCPs) makes these materials ideal for use as a soft matrix to support the structural ordering of the nanoparticles. In this work, a high-molecular-weight polystyrene-b-poly(methyl methacrylate) block copolymer (PS-b-PMMA) was synthesized through anionic polymerization. The influence of the addition of different ratios of PMMA-coated FePt nanoparticles (NPs) on the self-assembled morphology was investigated using transmission electron microscopy (TEM) and small-angle X-ray scattering (SAXS). The self-assembly of the NPs inside the PMMA phase at low particle concentrations was analyzed statistically, and the negative effect of higher particle ratios on the lamellar BCP morphology became visible. The placement of the NPs inside the PMMA phase was also compared to theoretical descriptions. The magnetic addressability of the FePt nanoparticles inside the nanocomposite films was finally analyzed using bimodal magnetic force microscopy and proved the magnetic nature of the nanoparticles inside the microphase-separated BCP films
Self-Assembly of Polymer-Modified FePt Magnetic Nanoparticles and Block Copolymers
The fabrication of nanocomposites containing magnetic nanoparticles is gaining interest as a
model for application in small electronic devices. The self-assembly of block copolymers (BCPs) makes
these materials ideal for use as a soft matrix to support the structural ordering of the nanoparticles.
In this work, a high-molecular-weight polystyrene-b-poly(methyl methacrylate) block copolymer (PSb-PMMA) was synthesized through anionic polymerization. The influence of the addition of different
ratios of PMMA-coated FePt nanoparticles (NPs) on the self-assembled morphology was investigated
using transmission electron microscopy (TEM) and small-angle X-ray scattering (SAXS). The selfassembly of the NPs inside the PMMA phase at low particle concentrations was analyzed statistically,
and the negative effect of higher particle ratios on the lamellar BCP morphology became visible. The
placement of the NPs inside the PMMA phase was also compared to theoretical descriptions. The
magnetic addressability of the FePt nanoparticles inside the nanocomposite films was finally analyzed
using bimodal magnetic force microscopy and proved the magnetic nature of the nanoparticles inside
the microphase-separated BCP films
A Novel MultiâFunctional ThiopheneâBased Organic Cation as Passivation, Crystalline Orientation, and Organic Spacer Agent for LowâDimensional 3D/1D Perovskite Solar Cells
Recently, the mixed-dimensional (3D/2D or 3D/1D) perovskite solar cells using small organic spacers have attracted interest due to their outstanding long-term stability. Here, a new type of thiophene-based organic cation 2-(thiophene-2yl-)pyridine-1-ium iodide (ThPyI), which is used to fabricate mixed-dimensional 3D/1D perovskite solar cells, is presented. The ThPyI-based 1D perovskitoid is applied as a passivator on top of a 3D methyl ammonium lead iodide (MAPI) to fabricate surface-passivated 3D/1D perovskite films or added alone into the 3D perovskite precursor to generate bulk-passivated 3D MAPI. The 1D perovskitoid acts as a passivating agent at the grain boundaries of surface-passivated 3D/1D, which improves the power conversion efficiency (PCE) of the solar cells. Grazing incidence wide-angle X-ray scattering (GIWAXS) studies confirm that ThPyI triggers the preferential orientation of the bulk MAPI slabs, which is essential to enhance charge transport. Champion bulk-passivated 3D and surface-passivated 3D/1D devices yield 14.10% and 19.60% PCE, respectively. The bulk-passivated 3D offers favorable stability, with 84% PCE retained after 2000 h without encapsulation. This study brings a new perspective to the design of organic spacers having a different binding motif and a passivation strategy to mitigate the impact of defects in hybrid 3D/1D perovskite solar cells
Morphology and photoluminescence study of titania nanoparticles
Titania nanoparticles are prepared by solâgel chemistry with a poly(ethylene oxide) methyl ether methacrylate-block-poly(dimethylsiloxane)-block-poly(ethylene oxide) methyl ether methacrylate triblock copolymer acting as the templating agent. The solâgel componentsâhydrochloric acid, titanium tetraisopropoxide, and triblock copolymerâare varied to investigate their effect on the resulting titania morphology. An increased titania precursor or polymer content yields smaller primary titania structures. Microbeam grazing incidence small-angle X-ray scattering measurements, which are analyzed with a unified fit model, reveal information about the titania structure sizes. These small structures could not be observed via the used microscopy techniques. The interplay among the solâgel components via our triblock copolymer results in different sized titania nanoparticles with higher packing densities. Smaller sized titania particles, (âŒ13â20 nm in diameter) in the range of exciton diffusion length, are formed by 2% by weight polymer and show good crystallinity with less surface defects and high oxygen vacancies
Formation of Al nanostructures on Alq3: An in situ grazing incidence small angle X-ray scattering study during radio frequency sputter deposition
6 pags., 4 figs., 1 sch.The formation of metal/organic interfaces is a complicated process involving chemical interaction, physical nucleation and diffusion, and thin film growth. It is closely related to the performance of organic electronic devices. To understand this process, we investigate the system of aluminum (Al) and tris(8-hydroxyquinolinato)aluminum (Alq3) as a model, owing to the well-known strong chemical interaction between both and their close technological relevance to organic light emitting devices. By using grazing small angle incidence X-ray scattering (GISAXS), we follow the Al thin film development on top of Alq3 during radio frequency (rf) sputter deposition in real-time and without interrupting the growth process. Three growth stages have been clearly distinguished: Al diffusion into Alq3, Al/Alq3 complex agglomeration and self-assembled Al pillar nanostructure thin film development. Thus in situ GISAXS yields the fundamental insights into the formation of the metal/organic interface for small organic semiconductor devices, prepared via vacuum based deposition techniques. © 2013 American Chemical Society.S.Y. acknowledges the Knut och Alice Wallenberg foundation for the kindfinancial support. P.M.-B., E.M., and K.S.acknowledge financial support by TUM.solar in the frame ofthe Bavarian Collaborative Research ProjectâSolar technologiesgo HybridâČâČ(SolTec) and by the GreenTech Initiative(Interface Science for Photovoltaics - ISPV) of the EuroTechUniversities. Portions of this research were carried out at thelight source PETRA III at DESY, a member of the Helmholtz Association (HGF). Dr. David Babonneau is acknowledged forhelpful discussion, and Erik Braden for the XRR measurementsPeer reviewe
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