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soft laser

Eduardo Oliva, Adrien Depresseux, Manuel Cotelo, Agustín Lifschitz, Fabien Tissandier, Julien Gautier, Gilles Maynard, Pedro Velarde, Stéphane Sebban
High-density, collisionally pumped plasma-based soft-x-ray lasers have recently delivered hundreds of femtosecond pulses, breaking the longstanding barrier of one picosecond. To pump these amplifiers an intense infrared pulse must propagate focused throughout all the length of the amplifier, which spans several Rayleigh lengths. However, strong nonlinear effects hinder the propagation of the laser beam. The use of a plasma waveguide allows us to overcome these drawbacks provided the hydrodynamic processes that dominate the creation and posterior evolution of the waveguide are controlled and optimized...
February 2018: Physical Review. E
Felix A Blyakhman, Nikita A Buznikov, Tatyana F Sklyar, Alexander P Safronov, Elizaveta V Golubeva, Andrey V Svalov, Sergey Yu Sokolov, Grigory Yu Melnikov, Iñaki Orue, Galina V Kurlyandskaya
Hydrogels are biomimetic materials widely used in the area of biomedical engineering and biosensing. Ferrogels (FG) are magnetic composites capable of functioning as magnetic field sensitive transformers and field assisted drug deliverers. FG can be prepared by incorporating magnetic nanoparticles (MNPs) into chemically crosslinked hydrogels. The properties of biomimetic ferrogels for multifunctional biosensor applications can be set up by synthesis. The properties of these biomimetic ferrogels can be thoroughly controlled in a physical experiment environment which is much less demanding than biotests...
March 15, 2018: Sensors
Yinfei Lu, Cornelius Louwrens Pieterse, Wesley Daniel Robertson, R J Dwayne Miller
We report the soft laser extraction and production of highly charged peptide and protein ions for mass spectrometry directly from bulk liquid water at atmospheric pressure and room temperature, using picosecond infrared laser ablation. Stable ion signal from singly charged small molecules, as well as highly charged biomolecular ions, from aqueous solutions at low laser pulse fluence (~0.3 J cm-2) is demonstrated. Sampling via single picosecond laser pulses is shown to extract less than 27 pL of volume from the sample, producing highly charged peptide and protein ions for mass spectrometry detection...
March 9, 2018: Analytical Chemistry
Yana Fu, Wuying Zhou, Wei Li, Xiaolei Lin, Qi Dai
RATIONALE: The incidence of cornea disorders after laser peripheral iridotomy (LPI) is extremely low. However, cornea Descemet membrane detachment (DMD) combined with corneal decompensation after LPI could still occur. PATIENT CONCERNS: A 69-year-old Chinese woman presented with persistent widespread corneal edema and inferior bullous lesions in her right eye for half a year. She had undergone LPI in both eyes 10 years ago for a prophylactic treatment. The patient received a detailed examination of vivo corneal confocal microscopy and sept-source optical coherence tomography (SS-OCT)...
March 2018: Medicine (Baltimore)
Jürgen Kampmeier, Jens Ulrich Werner, Peter Wagner, Gerhard K Lang, Detlef Russ
BACKGROUND: In microbial keratitis, thermal cautery leads to thermal necrosis associated with germ reduction. Subablative heating of the cornea using an Er : YAG laser or diode laser is an alternative option. Thermal effects and reproducibility of both procedures were investigated. MATERIAL AND METHODS: Thermal effects were monitored with an infrared imaging system. Temperature of stromal tissue of enucleated porcine eyes was measured. Effects of thermal injury were rated by microscopic photography and histopathologic examination...
March 7, 2018: Klinische Monatsblätter Für Augenheilkunde
Er-Jia Guo, Yaohua Liu, Changhee Sohn, Ryan D Desautels, Andreas Herklotz, Zhaoliang Liao, John Nichols, John W Freeland, Michael R Fitzsimmons, Ho Nyung Lee
Deliberate control of oxygen vacancy formation and migration in perovskite oxide thin films is important for developing novel electronic and iontronic devices. Here, it is found that the concentration of oxygen vacancies (VO ) formed in LaNiO3 (LNO) during pulsed laser deposition is strongly affected by the chemical potential mismatch between the LNO film and its proximal layers. Increasing the VO concentration in LNO significantly modifies the degree of orbital polarization and drives the metal-insulator transition...
March 7, 2018: Advanced Materials
Andrew Feeney, Margaret Lucas
The ability to design tuned ultrasonic devices that can be operated in the same mode at two different frequencies has the potential to benefit a range of applications, such as surgical cutting procedures where the penetration through soft then hard tissues could be enhanced by switching the operating frequency. The cymbal transducer has recently been adapted to form a prototype ultrasonic surgical cutting device that operates at a single frequency. In this paper, two different methods of configuring a dual-resonance cymbal transducer are detailed...
March 2018: IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
Joe Bennett
A testing methodology was developed to expose photopolymer resins and measure the cured material to determine two key parameters related to the photopolymerization process: Ec (critical energy to initiate polymerization) and Dp (penetration depth of curing light). Five commercially available resins were evaluated under exposure from 365 nm and 405 nm light at varying power densities and energies. Three different methods for determining the thickness of the cured resin were evaluated. Caliper measurements, stylus profilometry, and confocal laser scanning microscopy showed similar results for hard materials while caliper measurement of a soft, elastomeric material proved inaccurate...
December 2017: Additive Manufacturing
Marcel Heeger, Bonnie J Tyler, Martin Körsgen, Heinrich F Arlinghaus
In this study, the influence of two different cluster primary ions in laser secondary neutral mass spectrometry (Laser-SNMS) has been investigated. Despite the many advantages of Laser-SNMS, fragmentation of neutral organic molecules during both sputtering and photoionization has limited its efficiency for the study of large organic and biological molecules. Cluster ion sputtering, and in particular large argon gas cluster sputtering, has been proposed as a means of reducing this fragmentation. Molecules of 9-fluorenylmethoxycarbonyl-pentafluoro-l-phenylalanine were sputtered using Bi3 + and Ar2000 + cluster primary ions, and the desorbed neutral species ("secondary neutrals") were postionized using a 7...
March 2, 2018: Biointerphases
A Jonas, T Meurer, B Kanngießer, I Mantouvalou
The resolving power and relative efficiency of two off-axis reflection zone plates (RZPs) in the soft X-ray range between 1 nm and 5 nm were investigated. RZPs focus only a very narrow bandwidth around the design wavelength. By misaligning the RZP, the focused wavelength can be tuned through a much wider spectral range. Using a laser-produced plasma source, we demonstrate that a single RZP can be efficiently used for spectroscopy at arbitrary wavelengths in the investigated soft X-ray range.
February 2018: Review of Scientific Instruments
Adone Baroni
Xanthelasma palpebrarum is the most common type of xanthoma affecting the eyelids. It is characterized by asymptomatic soft yellowish macules, papules, or plaques over the upper and lower eyelids. Many treatments are available for management of xanthelasma palpebrarum, the most commonly used include surgical excision, ablative CO2 or erbium lasers, nonablative Q-switched Nd:YAG laser, trichloroacetic acid peeling, and radiofrequency ablation. This study aims to evaluate the effectiveness of RF ablation in the treatment of xanthelasma palpebrarum, with D...
March 1, 2018: Journal of Cosmetic Dermatology
Amélie Osio, Shuo Xu, Morad El Bouchtaoui, Christophe Leboeuf, Guillaume Gapihan, Christine Lemaignan, Guilhem Bousquet, Céleste Lebbé, Anne Janin, Maxime Battistella
Dermatofibrosarcoma protuberans (DFSP), amounting to 6% of all soft tissue sarcomas, has a slow growth rate, contrasting with a likelihood for local recurrence and a 10-20% evolution to higher-grade sarcoma, or "transformed DFSP" (DFSP-T). At molecular level, the characteristic COL1A1-PDGFB rearrangement, leading to sustained PDGFR signaling, is not linked to the evolutive potential. Here, we studied EGFR, another tyrosine kinase receptor, using laser-microdissection to select the different histologic components of DFSP (DFSP center, DFSP infiltrative periphery, DFSP-T higher-grade sarcoma), in 22 patients followed over 3 to 156 months...
February 2, 2018: Oncotarget
T Zogheib, R Jacobs, M M Bornstein, J O Agbaje, D Anumendem, Y Klazen, C Politis
Background: Three dimensional facial scanning is an innovation that provides opportunity for digital data acquisition, smile analysis and communication of treatment plan and outcome with patients. Objectives: To assess the applicability of 3D facial scanning as compared to 2D clinical photography. Materials & Methods: Sample consisted of thirty Caucasians aged between 25 and 50 years old, without any dentofacial deformities. Fifteen soft-tissue facial landmarks were identified twice by 3 observers on 2D and 3D images of the 30 subjects...
2018: Open Dentistry Journal
Marie Labat, Jean Blaise Brubach, Alessandra Ciavardini, Marie Emmanuelle Couprie, Erik Elkaim, Pierre Fertey, Tom Ferte, Philippe Hollander, Nicolas Hubert, Emmanuelle Jal, Claire Laulhé, Jan Luning, Olivier Marcouillé, Thierry Moreno, Paul Morin, Francois Polack, Pascale Prigent, Sylvain Ravy, Jean Paul Ricaud, Pascale Roy, Mathieu Silly, Fausto Sirotti, Amina Taleb, Marie Agnès Tordeux, Amor Nadji
The investigation of ultrafast dynamics, taking place on the few to sub-picosecond time scale, is today a very active research area pursued in a variety of scientific domains. With the recent advent of X-ray free-electron lasers (XFELs), providing very intense X-ray pulses of duration as short as a few femtoseconds, this research field has gained further momentum. As a consequence, the demand for access strongly exceeds the capacity of the very few XFEL facilities existing worldwide. This situation motivates the development of alternative sub-picosecond pulsed X-ray sources among which femtoslicing facilities at synchrotron radiation storage rings are standing out due to their tunability over an extended photon energy range and their high stability...
March 1, 2018: Journal of Synchrotron Radiation
Eduard Prat, Sven Reiche
X-ray free-electron lasers (FELs) are cutting-edge scientific tools able to generate transversely coherent radiation with very high power and ultra-short pulse durations. The self-seeding mechanism has been proven to increase the longitudinal coherence of the FEL radiation but its efficiency could be significantly improved, especially for soft X-rays. This paper proposes the enhancement of the performance of self-seeding by combining it with the harmonic generation mechanism. In particular, by starting the process with a subharmonic of the wavelength of interest, the coherence of the produced radiation is improved, the undulator beamline becomes more compact, and the monochromator realization is simplified...
March 1, 2018: Journal of Synchrotron Radiation
Nicolas Tancogne-Dejean, Angel Rubio
The generation of high-order harmonics from atomic and molecular gases enables the production of high-energy photons and ultrashort isolated pulses. Obtaining efficiently similar photon energy from solid-state systems could lead, for instance, to more compact extreme ultraviolet and soft x-ray sources. We demonstrate from ab initio simulations that it is possible to generate high-order harmonics from free-standing monolayer materials, with an energy cutoff similar to that of atomic and molecular gases. In the limit in which electrons are driven by the pump laser perpendicularly to the monolayer, they behave qualitatively the same as the electrons responsible for high-harmonic generation (HHG) in atoms, where their trajectories are described by the widely used semiclassical model, and exhibit real-space trajectories similar to those of the atomic case...
February 2018: Science Advances
J Y Liu, F Chen, Y J Ge, L Wei, S X Pan, H L Feng
OBJECTIVE: To evaluate the influence of the rough surface of dental implants prepared by selective laser melting (SLM) on early bone healing around titanium implants. METHODS: A total of sixteen titanium implants were involved in our research, of which eight implants were prepared by SLM (TIXOS Cylindrical, Leader-Novaxa, Milan, Italy; 3.3 mm×10 mm, internal hex) and the other eight were sandblasted, large-grit and acid-etched (SLA) implants (IMPLUS Cylindrical, Leader-Novaxa, Milan, Italy; 3...
February 18, 2018: Beijing da Xue Xue Bao. Yi Xue Ban, Journal of Peking University. Health Sciences
Zi-Yu Chen, Xiao-Ya Li, Bo-Yuan Li, Min Chen, Feng Liu
The production of intense isolated attosecond pulse is a major goal in ultrafast research. Recent advances in high harmonic generation from relativistic plasma mirrors under oblique incidence interactions gave rise to photon-rich attosecond pulses with circular or elliptical polarization. However, to achieve an isolated elliptical attosecond pulse via polarization gating using currently available long driving pulses remains a challenge, because polarization gating of high harmonics from relativistic plasmas is assumed only possible at normal or near-normal incidence...
February 19, 2018: Optics Express
Luca Poletto, Fabio Frassetto
The optical design of a plane-grating monochromator mainly intended for high resolution in the extreme ultraviolet and soft x-ray is presented. The configuration has three optical elements. It uses a uniform line-spaced plane grating illuminated in the converging light coming from a focusing concave mirror and an additional plane mirror that is needed to change the grating subtended angle to keep the system in focus on a fixed slit. The parameters of the focusing mirror are determined to introduce a coma that compensates for the coma given by the grating...
February 10, 2018: Applied Optics
Benjamin Zeeb, Vanessa Schöck, Nicole Schmid, Lisa Majer, Kurt Herrmann, Jörg Hinrichs, Jochen Weiss
Process-stable complexes composed of whey protein isolate (WPI) and sugar beet pectin have great potential as structuring agents or fat replacers in foods. The current study investigates the compatibility of heated WPI : pectin complexes in different meat matrices. Spreadable raw-fermented sausages and sliceable emulsion-type sausages were therefore manufactured containing biopolymer complexes with various WPI : pectin ratios r (2 : 1, 8 : 1). Macro- and microstructural properties of the meat dispersions were analyzed in terms of colour, texture, rheometry, sensory, and confocal laser scanning microscopy (CLSM) measurements...
February 22, 2018: Food & Function
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