Nanocrystal seeding: A low temperature route to polycrystalline Si films

A novel method is presented for growth of polycrystalline silicon films on amorphous substrates at temperatures of 540–575 °C. Grain nucleation and grain growth are performed in two steps, using Si nanocrystals as nuclei ("seeds"). The nanocrystal seeds are produced by excimer laser photolysis of disilane in a room temperature flow cell. Film (grain) growth occurs epitaxially on the seeds in a separate thermal chemical vapor deposition (CVD) step, with growth rates 10–100 times higher than similar CVD growth rates on crystal Si. Grain size and CVD growth rates are dependent on seed coverage, for seed coverage <0.2 monolayers

Permission form synopses to improve parents' understanding of research: a randomized trial.

ObjectiveWe hypothesized that, among parents of potential neonatal research subjects, an accompanying cover sheet added to the permission form (intervention) would increase understanding of the research, when compared to a standard form (control).Study designThis pilot study enrolled parents approached for one of two index studies: one randomized trial and one observational study. A one-page cover sheet described critical study information. Families were randomized 1:1 to receive the cover sheet or not. Objective and subjective understanding and satisfaction were measured.ResultsThirty-two parents completed all measures (17 control, 15 intervention). There were no differences in comprehension score (16.8±5.7 vs 16.3±3.5), subjective understanding (median 6 vs 6.5), or overall satisfaction with consent (median 7 vs 6.5) between control and intervention groups (all P&gt;0.50).ConclusionA simplified permission form cover sheet had no effect on parents' understanding of studies for which their newborns were being recruited

Probing Light Atoms at Sub-nanometer Resolution: Realization of Scanning Transmission Electron Microscope Holography

Atomic resolution imaging in transmission electron microscopy (TEM) and scanning TEM (STEM) of light elements in electron-transparent materials has long been a challenge. Biomolecular materials, for example, are rapidly altered when illuminated with electrons. These issues have driven the development of TEM and STEM techniques that enable the structural analysis of electron beam-sensitive and weakly scattering nano-materials. Here, we demonstrate such a technique, STEM holography, capable of absolute phase and amplitude object wave measurement with respect to a vacuum reference wave. We use an amplitude-dividing nanofabricated grating to prepare multiple spatially separated electron diffraction probe beams focused at the sample plane, such that one beam transmits through the specimen while the others pass through vacuum. We raster-scan the diffracted probes over the region of interest. We configure the post specimen imaging system of the microscope to diffraction mode, overlapping the probes to form an interference pattern at the detector. Using a fast-readout, direct electron detector, we record and analyze the interference fringes at each position in a 2D raster scan to reconstruct the complex transfer function of the specimen, t(x). We apply this technique to image a standard target specimen consisting of gold nanoparticles on a thin amorphous carbon substrate, and demonstrate 2.4 angstrom resolution phase images. We find that STEM holography offers higher phase-contrast of the amorphous material while maintaining Au atomic lattice resolution when compared with high angle annular dark field STEM.Comment: 9 pages, 5 figures in main text, 1 supplemental figure in the appendi

Synthesizing Skyrmion Molecules in Fe-Gd Thin Films

We show that properly engineered amorphous Fe-Gd alloy thin films with perpendicular magnetic anisotropy exhibit room-temperature skyrmion molecules, or a pair of like-polarity, opposite-helicity skyrmions. Magnetic mirror symmetry planes present in the stripe phase, instead of chiral exchange, determine the internal skyrmion structure and the net achirality of the skyrmion phase. Our study shows that stripe domain engineering in amorphous alloy thin films may enable the creation of skyrmion phases with technologically desirable properties.Comment: 15 pages, 6 figures. Accepted for publication in Applied Physics Letter

Interpretable and efficient contrast in scanning transmission electron microscopy with a diffraction grating beamsplitter

Efficient imaging of biomolecules, 2D materials and electromagnetic fields depends on retrieval of the phase of transmitted electrons. We demonstrate a method to measure phase in a scanning transmission electron microscope using a nanofabricated diffraction grating to produce multiple probe beams. The measured phase is more interpretable than phase-contrast scanning transmission electron microscopy techniques without an off-axis reference wave, and the resolution could surpass that of off-axis electron holography. We apply the technique to image nanoparticles, carbon sub- strates and electric fields. The contrast observed in experiments agrees well with contrast predicted in simulations

Optimizing Multi-Photon Fluorescence Microscopy Light Collection from Living Tissue by Non-Contact Total Emission Detection (TEDII)

Farrando Sicilia, Jordi; Fuente Fuente, Carlo

Non-pharmacological self-management for people living with migraine or tension-type headache:a systematic review including analysis of intervention components

ObjectivesTo assess the effect of non-pharmacological self-management interventions against usual care, and to explore different components and delivery methods within those interventionsParticipantsPeople living with migraine and/or tension-type headacheInterventionsNon-pharmacological educational or psychological self-management interventions; excluding biofeedback and physical therapy. We assessed the overall effectiveness against usual care on headache frequency, pain intensity, mood, headache related disability, quality of life, and medication consumption in meta-analysis. We also provide preliminary evidence on the effectiveness of intervention components and delivery methods.Results We found a small overall effect for the superiority of self-management interventions over usual care, with a SMD of-0.36 (-0.45 to -0.26) for pain intensity; -0.32 (-0.42 to -0.22) for headache related disability, 0.32 (0.20 to 0.45) for quality of life and a moderate effect on mood (SMD = 0.53 (-0.66 to -0.40)). We did not find an effect on headache frequency (SMD = -0.07 (-0.22 to 0.08). Assessment of components and characteristics suggests a larger effects on pain intensity in interventions that included explicit educational components (-0.51 (-0.68 to -0.34) versus -0.28 (-0.40 to -0.16)); mindfulness components (-0.50 (-0.82 to -0.18) versus 0.34 (-0.44 to -0.24) and in interventions delivered in groups versus one-to-one delivery (0.56 (-0.72 to -0.40) versus -0.39 (-0.52 to -0.27) and larger effects on mood in interventions including a CBT component with a SMD of -0.72 (-0.93 to -0.51) compared to those without CBT -0.41 (-0.58 to -0.24). Conclusion Overall we found that self-management interventions for migraine and tension-type headache are more effective than usual care in reducing pain intensity, mood, and headache related disability. Preliminary findings also suggest that including CBT, mindfulness and educational components in interventions, and delivery in groups may increase effectiveness.RegistrationPROSPERO 2016:CRD4201604129

D’Agents: Security in a Multiple-Language, Mobile-Agent System

Abstract. Mobile-agent systems must address three security issues: protecting an individual machine, protecting a group of machines, and protecting an agent. In this chapter, we discuss these three issues in the context of D’Agents, a mobile-agent system whose agents can be written in Tcl, Java and Scheme. (D’Agents was formerly known as Agent Tcl.) First we discuss mechanisms existing in D’Agents for protecting an individual machine: (1) cryptographic authentication of the agent’s owner, (2) resource managers that make policy decisions based on the owner’s identity, and (3) secure execution environments for each language that enforce the decisions of the resource managers. Then we discuss our planned market-based approach for protecting machine groups. Finally we consider several (partial) solutions for protecting an agent from a malicious machine.