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high harmonic generation

D Melancon, Z S Bagheri, R B Johnston, L Liu, M Tanzer, D Pasini
Porous biomaterials can be additively manufactured with micro-architecture tailored to satisfy the stringent mechano-biological requirements imposed by bone replacement implants. In a previous investigation, we introduced structurally porous biomaterials, featuring strength five times stronger than commercially available porous materials, and confirmed their bone ingrowth capability in an in-vivo canine model. While encouraging, the manufactured biomaterials showed geometric mismatches between their internal porous architecture and that of its as-designed counterpart, as well as discrepancies between predicted and tested mechanical properties, issues not fully elucidated...
September 16, 2017: Acta Biomaterialia
Emerson Coy, Piotr Graczyk, Luis Yate, Karol Załęski, Jacek Gapiński, Piotr Kuświk, Sławomir Mielcarek, Feliks Stobiecki, Bogusław Mróz, Cesar Ferrater, Stefan Jurga
Gd2(MoO4)3 (GMO) is a well-studied multiferroic material that exhibits full ferroelectric and ferroelastic behavior at room temperature. However, its difficult stabilization in thin films has prevented the study and exploitation of its multiferroic properties in different architectures. Here, we report on the study of GMO thin films deposited on Si(001) substrates by Pulsed Laser Deposition (PLD). The physicochemical properties of the films are discussed and studied. Results obtained by X-ray diffraction, X-ray photoelectron spectroscopy, high resolution transmission microscopy and second harmonic generation show that the orthorhombic (β'-GMO) multiferroic phase can be stabilized and homogenized by post deposition thermal reconstruction...
September 18, 2017: Scientific Reports
Claudio Vergari, Jessica C Mansfield, Daniel Chan, Andrew Clarke, Judith R Meakin, Peter C Winlove
Needle puncture of the intervertebral disc can initiate a mechanical and biochemical cascade leading to disc degeneration. Puncture's mechanical effects have been shown near the puncture site, mechanical effects should be observed far, relative to needle size, from the puncture site, given the disc-wide damage induced by the stab. The aim of this work was to quantify these far-field effects, and to observe the local structural damage provoked by the needle. Strips of cow tail annulus fibrosus underwent two consecutive mechanical loadings to 5% tensile strain; fifteen samples were punctured in a radial direction with a randomly assigned needle between the two loadings (needle gauges between 19 and 23)...
September 13, 2017: Acta Biomaterialia
Nico J Claassens, Melvin F Siliakus, Sebastiaan K Spaans, Sjoerd C A Creutzburg, Bart Nijsse, Peter J Schaap, Tessa E F Quax, John van der Oost
High-level, recombinant production of membrane-integrated proteins in Escherichia coli is extremely relevant for many purposes, but has also been proven challenging. Here we study a combination of transcriptional fine-tuning in E. coli LEMO21(DE3) with different codon usage algorithms for heterologous production of membrane proteins. The overexpression of 6 different membrane proteins is compared for the wild-type gene codon usage variant, a commercially codon-optimized variant, and a codon-harmonized variant...
2017: PloS One
Daniela Rupp, Nils Monserud, Bruno Langbehn, Mario Sauppe, Julian Zimmermann, Yevheniy Ovcharenko, Thomas Möller, Fabio Frassetto, Luca Poletto, Andrea Trabattoni, Francesca Calegari, Mauro Nisoli, Katharina Sander, Christian Peltz, Marc J Vrakking, Thomas Fennel, Arnaud Rouzée
Coherent diffractive imaging of individual free nanoparticles has opened routes for the in situ analysis of their transient structural, optical, and electronic properties. So far, single-shot single-particle diffraction was assumed to be feasible only at extreme ultraviolet and X-ray free-electron lasers, restricting this research field to large-scale facilities. Here we demonstrate single-shot imaging of isolated helium nanodroplets using extreme ultraviolet pulses from a femtosecond-laser-driven high harmonic source...
September 8, 2017: Nature Communications
Matthew D Perkins, Dane Elles, George Badlissi, Amin Mivehchi, Jason Dahl, Stephen Licht
In this paper, we investigate the effect of operating near a solid boundary on the forces produced by harmonically oscillating thrust generating foils. A rolling and pitching foil was towed in a freshwater tank in a series of experiments with varying kinematics. Hydrodynamic forces and torques were measured in the free stream and at varying distances from a solid boundary, and changes in mean lift and thrust were found when the foil approached the boundary. The magnitude of this ground effect exhibited a strong nonlinear dependence on the distance between the foil and the boundary...
September 4, 2017: Bioinspiration & Biomimetics
Clara Correa-Soto, Niraj S Trasi, Paul D Schmitt, Yongchao Su, Zhen Liu, Elise Miller, Narayan Variankaval, Patrick J Marsac, Garth J Simpson, Lynne S Taylor
Various techniques have been used to detect crystallization in amorphous solid dispersions (ASD). However, most of these techniques do not enable the detection of very low levels of crystallinity (<1%). The aim of the current study was to compare the sensitivity of second harmonic generation (SHG) microscopy with powder X-ray diffraction (XRPD) in detecting the presence of crystals in low drug loading amorphous solid dispersions. Amorphous solid dispersions of the poorly water soluble compounds, flutamide (FTM, 15wt...
August 24, 2017: Journal of Pharmaceutical and Biomedical Analysis
Gediminas Galinis, Jergus Strucka, Jonathan C T Barnard, Avi Braun, Roland A Smith, Jon P Marangos
Thin liquid sheet jet flows in vacuum provide a new platform for performing experiments in the liquid phase, for example X-ray spectroscopy. Micrometer thickness, high stability, and optical flatness are the key characteristics required for successful exploitation of these targets. A novel strategy for generating sheet jets in vacuum is presented in this article. Precision nozzles were designed and fabricated using high resolution (0.2 μm) 2-photon 3D printing and generated 1.49 ± 0.04 μm thickness, stable, and <λ/20-flat jets in isopropanol under normal atmosphere and under vacuum at 5 × 10(-1) mbar...
August 2017: Review of Scientific Instruments
Yongming Zao, Qi Ouyang, Jiawei Chen, Xinglan Zhang, Shuaicheng Hou
This paper investigates the design and implementation of an improved series-parallel inductor-capacitor-inductor (LsCpLp) resonant circuit power supply for excitation of electromagnetic acoustic transducers (EMATs). The main advantage of the proposed resonant circuit is the absence of a high-permeability dynamic transformer. A high-frequency pulsating voltage gain can be achieved through a double resonance phenomenon. Both resonant tailing behavior and higher harmonics are suppressed by the improved resonant circuit, which also contributes to the generation of ultrasonic waves...
August 2017: Review of Scientific Instruments
J Schmidt, A Guggenmos, S H Chew, A Gliserin, M Högner, M F Kling, J Zou, C Späth, U Kleineberg
We present a newly developed high harmonic beamline for time-, angle-, and carrier-envelope phase-resolved extreme ultraviolet photoemission spectroscopy on solid targets for the investigation of ultrafast band structure dynamics in the low-fs to sub-fs time regime. The source operates at a repetition rate of 10 kHz and is driven by 5 fs few-cycle near-infrared laser pulses generating high harmonic radiation with photon energies up to 120 eV at a feasible flux. The experimental end station consists of a complementary combination of photoelectron detectors which are able to spectroscopically address electron dynamics both in real and in k-space...
August 2017: Review of Scientific Instruments
Yun-Yi Pai, Anthony Tylan-Tyler, Patrick Irvin, Jeremy Levy
1 Overview 1 1.1 Introduction 1 1.1.1 Oxide growth techniques are rooted in search for high-Tc superconductors 2 1.1.2 First reports of interface conductivity 2 1.2 2D physics 2 1.3 Emergent properties of oxide heterostructures and nanostructures 3 1.4 Outline 3 2 Relevant properties of SrTiO3 3 2.1 Structural properties and transitions 3 2.2 Ferroelectricity, Paraelectricity and Quantum Paraelectricity 4 2.3 Electronic structure 5 2.4 Defects 6 2...
August 30, 2017: Reports on Progress in Physics
Gui-Ming Pan, Da-Jie Yang, Li Zhou, Zhong-Hua Hao, Qu-Quan Wang
We theoretically study the gain-assisted double plasmonic resonances to enhance second harmonic generation (SHG) in a centrosymmetric multilayered silver-dielectric-gold-dielectric (SDGD) nanostructure. Introducing gain media into the dielectric layers can not only compensate the dissipation and lead to giant amplification of surface plasmons (SPs), but also excite local quadrupolar plasmon which can boost SHG by mode matching. Specifically, as the quadrupolar mode dominates SHG in our nanostructure, under the mode matching condition, the intensity of second harmonic near-field can be enhanced by 4...
August 29, 2017: Scientific Reports
Stefan Kroboth, Kelvin J Layton, Feng Jia, Sebastian Littin, Huijun Yu, Jurgen Hennig, Maxim Zaitsev
OBJECTIVE: Recently, matrix gradient coils (also termed multi-coils or multi-coil arrays) were introduced for imaging and B0 shimming with 24, 48 and even 84 coil elements. However, in imaging applications, providing one amplifier per coil element is not always feasible due to high cost and technical complexity. In this simulation study we show that an 84-channel matrix gradient coil (head insert for brain imaging) is able to create a wide variety of field shapes even if the number of amplifiers is reduced...
August 23, 2017: IEEE Transactions on Medical Imaging
Yu Zhou, Di Wu, Yihan Zhu, Yujin Cho, Qing He, Xiao Yang, Kevin Herrera, Zhaodong Chu, Yu Han, Michael C Downer, Hailin Peng, Keji Lai
Piezoelectric and ferroelectric properties in the two-dimensional (2D) limit are highly desired for nanoelectronic, electromechanical, and optoelectronic applications. Here we report the first experimental evidence of out-of-plane piezoelectricity and ferroelectricity in van der Waals layered α-In2Se3 nanoflakes. The noncentrosymmetric R3m symmetry of the α-In2Se3 samples is confirmed by scanning transmission electron microscopy, second-harmonic generation, and Raman spectroscopy measurements. Domains with opposite polarizations are visualized by piezo-response force microscopy...
September 13, 2017: Nano Letters
Riccardo Cicchi, Francesco S Pavone
Second-harmonic generation (SHG) microscopy is a powerful microscopy technique for imaging collagen and other biological molecules using a label-free approach. SHG microscopy offers the advantages of a nonlinear imaging modality together with those ones of a coherent technique. These features make SHG microscopy the ideal tool for imaging collagen at high resolution and for characterizing its organization at various hierarchical levels. Considering that collagen organization plays a crucial role in fibrosis and in its development, it would be beneficial for the researcher working in the field of fibrosis to have a manual listing crucial points to be considered when imaging collagen using SHG microscopy...
2017: Methods in Molecular Biology
Doyeon Bang, Eun-Jung Jo, SoonGweon Hong, Ju-Young Byun, Jae Young Lee, Min-Gon Kim, Luke P Lee
Frequency upconversion activated with Lanthanide has attracted attention in various real-world applications, because it is far simpler and more efficient than traditional nonlinear susceptibility-based frequency upconversion, such as second harmonic generation. However, the quantum yield of frequency upconversion of Lanthanide-based upconversion nanoparticles remains inefficient for practical applications, and spatial control of upconverted emission is not yet developed. To overcome this limitation, we developed asymmetric hetero-plasmonic nanoparticles (AHPNs) consisting of plasmonic antennae in nanocrescent shapes on the Lanthanide-based upconversion nanoparticle (UC) for efficiently delivering excitation light to the UC core by nanofocusing of light and generating asymmetric frequency upconverted emission concentrated toward the tip region...
August 21, 2017: Nano Letters
Hongwen Xuan, Chen Qu, Shinji Ito, Yohei Kobayashi
We report a 10 kHz, 10.5 W deep ultraviolet (DUV) laser at 258 nm with a pulse duration of 3 ns by fourth-harmonic generation (FHG) in a CsLiB6O10 crystal with high-conversion efficiency. The fundamental laser is at 1030 nm with 35 W output power consisting of a Yb:YAG ceramics thin rod amplifier. The M(2) of the DUV laser was confirmed to be <1.5. To the best of our knowledge, this is the best beam quality for DUV laser power higher than 10 W generated by FHG of a solid-state laser, as well as the highest conversion efficiency of 31% from infrared to DUV so far...
August 15, 2017: Optics Letters
Omri Wolf, Salvatore Campione, Yuanmu Yang, Igal Brener
Optical nonlinearities are intimately related to the spatial symmetry of the nonlinear media. For example, the second order susceptibility vanishes for centrosymmetric materials under the dipole approximation. The latter concept has been naturally extended to the metamaterials' realm, sometimes leading to the (erroneous) hypothesis that second harmonic (SH) generation is negligible in highly symmetric meta-atoms. In this work we aim to show that such symmetric meta-atoms can radiate SH light efficiently. In particular, we investigate in-plane centrosymmetric meta-atom designs where the approximation for meta-atoms breaks down...
August 14, 2017: Scientific Reports
Yazhou Wang, Jianfeng Li, Kundong Mo, Yanyan Wang, Fei Liu, Yong Liu
We demonstrate a high repetition rate passive harmonic mode-locking (HML) based on nonlinear polarization evolution (NPE) technique in a Tm-doped ring fiber laser cavity. Small net anomalous cavity dispersion based on dispersion compensation benefited the generation of high repetition rate HML due to the low soliton splitting threshold. Stable HML with a repetition rate of up to 14.5 GHz and a super-mode suppression (SSR) of 19 dB was obtained at the center wavelength of 1982.3 nm, which is about ten times of state of the art at 2 μm band mode-locking fiber laser to our best knowledge...
August 10, 2017: Scientific Reports
Yalun Wang, Xiao Han, Wang Xi, Jinyu Li, Anna Wang Roe, Ping Lu, Jun Qian
Deep-tissue imaging is of great significance to biological applications. In this paper, a deep-red emissive luminogen 2,3-bis(4'-(diphenylamino)-[1,1'-biphenyl]-4-yl) fumaronitrile (TPATCN) with aggregation-induced emission (AIE) feature is prepared. TPATCN molecules were then encapsulated within a polymeric matrix of Pluronic F-127 to form nanoparticles (NPs). TPATCN NPs exhibit bright three-photon fluorescence (3PF) in deep-red region, together with high chemical stability, good photostability, and biocompatibility...
August 10, 2017: Advanced Healthcare Materials
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