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https://www.readbyqxmd.com/read/28630909/dynamic-fracture-of-tantalum-under-extreme-tensile-stress
#1
Bruno Albertazzi, Norimasa Ozaki, Vasily Zhakhovsky, Anatoly Faenov, Hideaki Habara, Marion Harmand, Nicholas Hartley, Denis Ilnitsky, Nail Inogamov, Yuichi Inubushi, Tetsuya Ishikawa, Tetsuo Katayama, Takahisa Koyama, Michel Koenig, Andrew Krygier, Takeshi Matsuoka, Satoshi Matsuyama, Emma McBride, Kirill Petrovich Migdal, Guillaume Morard, Haruhiko Ohashi, Takuo Okuchi, Tatiana Pikuz, Narangoo Purevjav, Osami Sakata, Yasuhisa Sano, Tomoko Sato, Toshimori Sekine, Yusuke Seto, Kenjiro Takahashi, Kazuo Tanaka, Yoshinori Tange, Tadashi Togashi, Kensuke Tono, Yuhei Umeda, Tommaso Vinci, Makina Yabashi, Toshinori Yabuuchi, Kazuto Yamauchi, Hirokatsu Yumoto, Ryosuke Kodama
The understanding of fracture phenomena of a material at extremely high strain rates is a key issue for a wide variety of scientific research ranging from applied science and technological developments to fundamental science such as laser-matter interaction and geology. Despite its interest, its study relies on a fine multiscale description, in between the atomic scale and macroscopic processes, so far only achievable by large-scale atomic simulations. Direct ultrafast real-time monitoring of dynamic fracture (spallation) at the atomic lattice scale with picosecond time resolution was beyond the reach of experimental techniques...
June 2017: Science Advances
https://www.readbyqxmd.com/read/28630409/two-dimensional-fluorescence-spectroscopy-of-uranium-isotopes-in-femtosecond-laser-ablation-plumes
#2
Mark C Phillips, Brian E Brumfield, Nicole LaHaye, Sivanandan S Harilal, Kyle C Hartig, Igor Jovanovic
We demonstrate measurement of uranium isotopes in femtosecond laser ablation plumes using two-dimensional fluorescence spectroscopy (2DFS). The high-resolution, tunable CW-laser spectroscopy technique clearly distinguishes atomic absorption from (235)U and (238)U in natural and highly enriched uranium metal samples. We present analysis of spectral resolution and analytical performance of 2DFS as a function of ambient pressure. Simultaneous measurement using time-resolved absorption spectroscopy provides information on temporal dynamics of the laser ablation plume and saturation behavior of fluorescence signals...
June 19, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28629164/cataract-surgery-performed-by-high-frequency-ldv-z8-femtosecond-laser-safety-efficacy-and-its-physical-properties
#3
Bojan Pajic, Zeljka Cvejic, Brigitte Pajic-Eggspuehler
BACKGROUND: The aim of our study was to investigate the safety and efficacy of the LDV Z8 femtosecond laser in cataract surgery compared to the conventional procedure. METHODS: This prospective study was performed at the Swiss Eye Research Foundation, Eye Clinic ORASIS, Reinach, Switzerland. The study included 130 eyes from 130 patients: 68 treated with femtosecond laser-assisted cataract surgery (FLACS) using the FEMTO LDV Z8 and 62 treated with conventional phacoemulsification...
June 18, 2017: Sensors
https://www.readbyqxmd.com/read/28628129/high-speed-fixed-target-serial-virus-crystallography
#4
Philip Roedig, Helen M Ginn, Tim Pakendorf, Geoff Sutton, Karl Harlos, Thomas S Walter, Jan Meyer, Pontus Fischer, Ramona Duman, Ismo Vartiainen, Bernd Reime, Martin Warmer, Aaron S Brewster, Iris D Young, Tara Michels-Clark, Nicholas K Sauter, Abhay Kotecha, James Kelly, David J Rowlands, Marcin Sikorsky, Silke Nelson, Daniel S Damiani, Roberto Alonso-Mori, Jingshan Ren, Elizabeth E Fry, Christian David, David I Stuart, Armin Wagner, Alke Meents
We report a method for serial X-ray crystallography at X-ray free-electron lasers (XFELs), which allows for full use of the current 120-Hz repetition rate of the Linear Coherent Light Source (LCLS). Using a micropatterned silicon chip in combination with the high-speed Roadrunner goniometer for sample delivery, we were able to determine the crystal structures of the picornavirus bovine enterovirus 2 (BEV2) and the cytoplasmic polyhedrosis virus type 18 polyhedrin, with total data collection times of less than 14 and 10 min, respectively...
June 19, 2017: Nature Methods
https://www.readbyqxmd.com/read/28622316/corneal-densitometry-after-photorefractive-keratectomy-laser-assisted-in-situ-keratomileusis-and-small-incision-lenticule-extraction
#5
F Poyales, N Garzón, J Mendicute, I Illarramendi, P Caro, O Jáñez, F Argüeso, A López
PurposeThe aim of this study was to gain greater insight into the corneal densitometry changes occurring as a result of refractive surgery and to compare these changes across three widely used surgical techniques, namely, photorefractive keratectomy (PRK), laser-assisted in situ keratomileusis with a femtosecond laser (LASIK-FS), or ReLEx small-incision lenticule extraction (ReLEx SMILE).Patients and methodsThree hundred and thirty-six patients (184 male and 152 female patients) participated in this study. They were split into three groups according to the refractive surgery technique they had undergone: LASIK-FS (74 patients), PRK (153 patients), and ReLEx SMILE (109 patients)...
June 16, 2017: Eye
https://www.readbyqxmd.com/read/28621306/targeted-two-photon-chemical-apoptotic-ablation-of-defined-cell-types-in-vivo
#6
Robert A Hill, Eyiyemisi C Damisah, Fuyi Chen, Alex C Kwan, Jaime Grutzendler
A major bottleneck limiting understanding of mechanisms and consequences of cell death in complex organisms is the inability to induce and visualize this process with spatial and temporal precision in living animals. Here we report a technique termed two-photon chemical apoptotic targeted ablation (2Phatal) that uses focal illumination with a femtosecond-pulsed laser to bleach a nucleic acid-binding dye causing dose-dependent apoptosis of individual cells without collateral damage. Using 2Phatal, we achieve precise ablation of distinct populations of neurons, glia and pericytes in the mouse brain and in zebrafish...
June 16, 2017: Nature Communications
https://www.readbyqxmd.com/read/28618605/measurements-of-ionization-states-in-warm-dense-aluminum-with-betatron-radiation
#7
M Z Mo, Z Chen, S Fourmaux, A Saraf, S Kerr, K Otani, R Masoud, J-C Kieffer, Y Tsui, A Ng, R Fedosejevs
Time-resolved measurements of the ionization states of warm dense aluminum via K-shell absorption spectroscopy are demonstrated using betatron radiation generated from laser wakefield acceleration as a probe. The warm dense aluminum is generated by irradiating a free-standing nanofoil with a femtosecond optical laser pulse and was heated to an electron temperature of ∼20-25 eV at a close-to-solid mass density. Absorption dips in the transmitted x-ray spectrum due to the Al^{4+} and Al^{5+} ions are clearly seen during the experiments...
May 2017: Physical Review. E
https://www.readbyqxmd.com/read/28616700/evaluation-of-irradiation-effects-of-near-infrared-free-electron-laser-of-silver-alloy-for-dental-application
#8
Takao Kuwada-Kusunose, Alisa Kusunose, Masanobu Wakami, Chikako Takebayashi, Haruhiko Goto, Masahiro Aida, Takeshi Sakai, Keisuke Nakao, Kyoko Nogami, Manabu Inagaki, Ken Hayakawa, Kunihiro Suzuki, Toshiro Sakae
In the application of lasers in dentistry, there is a delicate balance between the benefits gained from laser treatment and the heat-related damage arising from laser irradiation. Hence, it is necessary to understand the different processes associated with the irradiation of lasers on dental materials. To obtain insight for the development of a safe and general-purpose laser for dentistry, the present study examines the physical effects associated with the irradiation of a near-infrared free-electron laser (FEL) on the surface of a commonly used silver dental alloy...
June 14, 2017: Lasers in Medical Science
https://www.readbyqxmd.com/read/28615924/comparison-of-the-frequency-of-use-of-a-pupil-expansion-device-with-and-without-an-intracameral-phenylephrine-and-ketorolac-injection-1-0-3-at-the-time-of-routine-cataract-surgery
#9
Frank A Bucci, Breanne Michalek, Angel T Fluet
PURPOSE: The objective of this study is to evaluate whether a phenylephrine and ketorolac injection 1%/0.3% (phenyl/keto injection) (Omidria(®)) prior to capsulotomy decreases the need for the Malyugin Ring(®) to manage small pupils. SETTING: Bucci Laser Vision Institute, Wilkes-Barre, PA, USA. DESIGN: Retrospective analysis of cataract surgeries performed by a single surgeon at a single center. METHODS: A historical control group of 1,004 consecutive cases (December 2013 to February 2015) did not receive a phenyl/keto intracameral injection prior to capsulotomy and were compared with 915 consecutive cases in the treatment group (June 2015 to April 2016) for the rate of use of the Malyugin Ring...
2017: Clinical Ophthalmology
https://www.readbyqxmd.com/read/28614344/self-starting-dropout-free-harmonic-mode-locked-soliton-fiber-laser-with-a-low-timing-jitter
#10
Qiang Hao, Yunfeng Wang, Peng Luo, Hong Hu, Heping Zeng
We demonstrate a simple, but robust, self-starting environmentally stable passive harmonic mode-locked femtosecond Er-fiber laser with a scalable repetition rate of up to the 10th harmonic and >50  dB of supermode suppression. The repetition rate of short- and long-term operation for each harmonic appears to have no pulse dropout. Furthermore, at as low as 0.8 and 2.1 mHz standard deviation, the repetition rate is achieved by using the pump-induced nonlinearity to modulate the refractive index of the gain fiber...
June 15, 2017: Optics Letters
https://www.readbyqxmd.com/read/28614309/femtosecond-laser-one-step-direct-writing-cylindrical-microlens-array-on-fused-silica
#11
Zhi Luo, Ji'an Duan, Chunlei Guo
We demonstrate an efficient method for fabricating high-quality cylindrical microlens arrays (CMLAs) on the surface of fused silica, fully based on spatially shaping of a femtosecond laser beam from Gaussian to Bessel distribution. As the envelope of shaped spatial intensity distribution matches the profile of cylindrical microlens perfectly, a CMLA with more than 50 uniform microlenses is fabricated by simple line scanning. The radius and height of these microlens units can be finely controlled by adjusting the power of laser pulses...
June 15, 2017: Optics Letters
https://www.readbyqxmd.com/read/28611133/long-term-clinical-outcome-of-femtosecond-laser-assisted-lamellar-keratectomy-with-phototherapeutic-keratectomy-in-anterior-corneal-stromal-dystrophy
#12
Jonghyun Lee, Jin Hyoung Kim, Doh Lee, Ji Woong Chang, Joo Youn Shin, Ji Won Seo, Min Hwan Seo, Nam Ju Moon
PURPOSE: To evaluate long-term outcome of femtosecond laser-assisted lamellar keratectomy (FLK) with phototherapeutic keratectomy (PTK) in patients with anterior corneal stromal dystrophies. METHODS: A total of 10 eyes from seven patients who underwent FLK were included. The patients had suffered from recurrent corneal erosion or visual disturbance in anterior corneal dystrophies (five Avellino dystrophies and two lattice dystrophies). Planar-shaped lamellar keratectomy was performed using femtosecond laser...
June 13, 2017: British Journal of Ophthalmology
https://www.readbyqxmd.com/read/28608030/intracorneal-ring-segment-depth-in-keratoconus-patients-a-long-term-follow-up-study
#13
Saied Shahhoseini, Hassan Hashemi, Soheila Asgari
PURPOSE: To compare the actual depth of the tunnel created with femtosecond laser for intracorneal ring segment (ICRS) implantation with the target depth in keratoconus patients. METHODS: In this mix design study, eligible keratoconus patients were identified through chart review. The inclusion criterion was a history of ICRS implantation with femtosecond laser more than 6 months prior to enrollment. Participants underwent anterior segment optical coherence tomography using Spectralis (Heidelberg Engineering GmbH, Heidelberg, Germany) for depth measurement defined as the distance from the anterior corneal surface to anterior rim of the ring...
June 12, 2017: International Ophthalmology
https://www.readbyqxmd.com/read/28604979/femtosecond-laser-assisted-cataract-in-vitreoretinal-surgery
#14
Stanislao Rizzo, Daniela Bacherini, Francesco Faraldi, Marco Pellegrini, Cesare Mariotti
PURPOSE: To assess the safety and surgical results of femtosecond laser-assisted phacovitrectomy. METHODS: Fifteen patients over 50 years of age with coexisting vitreoretinal pathologies and cataract underwent combined femtosecond laser-assisted cataract extraction and sutureless 25-G and 27-G vitreoretinal surgery. RESULTS: The indication for surgery was macular hole in 6 patients, epiretinal membrane in 6, vitreous hemorrhage in 2, and retinal detachment in 1...
June 2, 2017: European Journal of Ophthalmology
https://www.readbyqxmd.com/read/28602334/intraindividual-comparative-analysis-of-the-visual-performance-after-cataract-surgery-with-implantation-of-a-trifocal-and-a-bifocal-intraocular-lens
#15
Ghada Al-Khateeb, Mehdi Shajari, Thomas Kohnen
Presbyopia-treating intraocular lenses (IOLs) are now widely available and offer high predictability at all distances, better visual outcomes, and high patient satisfaction. In most patients, the same multifocal IOL is implanted bilaterally. In certain circumstances, such as during complex surgeries, it is important to be prepared with a backup plan to maintain surgical expectations. We report 3 patients who had femtosecond laser-assisted cataract surgeries in both eyes. The complicated eye had implantation of a bifocal IOL and the fellow eye of a trifocal IOL...
May 2017: Journal of Cataract and Refractive Surgery
https://www.readbyqxmd.com/read/28601345/comparison-of-12-month-anatomic-and-functional-results-between-z6-femtosecond-laser-assisted-and-manual-trephination-in-deep-anterior-lamellar-keratoplasty-for-advanced-keratoconus
#16
A Blériot, E Martin, P Lebranchu, K Zimmerman, L Libeau, M Weber, B Vabres, I Orignac
The management of severe keratoconus requires corneal transplantation, for which the gold standard is deep anterior lamellar keratoplasty (DALK), preserving the healthy Descemet's membrane and endothelium. The safety and reproducibility of corneal cuts have been improved by the evolution of femtosecond lasers in refractive surgery, and femtosecond laser in DALK would seem to provide the same advantages over the manual method. In our retrospective study, we compare functional and anatomical results of femtosecond-assisted DALK versus manual trephination DALK in patients with keratoconus in stage 4 of the Krumeich classification...
June 7, 2017: Journal Français D'ophtalmologie
https://www.readbyqxmd.com/read/28597901/a-perspective-for-investigating-photo-induced-molecular-dynamics-from-within-with-femtosecond-free-electron-lasers
#17
Nora Berrah
Photo-induced molecular dynamics can now be investigated using free electron lasers (FELs) whose attributes are unprecedented brightness, few femtosecond pulses duration and in the near future few hundreds of attosecond pulse duration. These relatively new tools are utilized to investigate photon-induced physical and chemical processes by ionizing inner-shell electrons and thus unlocking molecular dynamics from within.
June 9, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28595155/multielectron-dissociative-ionization-of-methane-and-formaldehyde-molecules-with-optimally-tailored-intense-femtosecond-laser-pulses
#18
E Irani, A Anvari, R Sadighi-Bonabi, M Monfared
The multielectron dissociative ionization of CH4 and CH2O molecules has been investigated using optimum convolution of different dual tailored short laser pulses. Based on three dimensional molecular dynamics simulations and TDDFT approach, the dissociation probability is enhanced by designing the dual chirped-chirped laser pulses and chirped-ordinary laser pulses for formaldehyde molecule. However, it is interesting to notice that the sensitivity of enhanced dissociation probability into different tailored laser pulses is not significant for methane molecule...
May 31, 2017: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
https://www.readbyqxmd.com/read/28594697/comparison-of-femtosecond-laser-enabled-descemetorhexis-and-manual-descemetorhexis-in-descemet-membrane-endothelial-keratoplasty
#19
Adi Einan-Lifshitz, Nir Sorkin, Tanguy Boutin, Mahmood Showail, Armand Borovik, Murad Alobthani, Clara C Chan, David S Rootman
PURPOSE: To introduce a novel method to perform descemetorhexis in Descemet membrane endothelial keratoplasty (DMEK) using the femtosecond laser and to compare it with Descemet membrane endothelial keratoplasty performed with manual descemetorhexis (M-DMEK). METHODS: A retrospective medical chart review of 2 groups of patients who underwent DMEK surgery combined with cataract surgery secondary to Fuchs corneal endothelial dystrophy and cataract: 17 patients underwent femtosecond laser-enabled descemetorhexis Descemet membrane endothelial keratoplasty (FE-DMEK) and 89 patients underwent DMEK surgery with M-DMEK...
July 2017: Cornea
https://www.readbyqxmd.com/read/28590837/regulation-and-measurement-of-the-heat-generated-by-automatic-tooth-preparation-in-a-confined-space
#20
Fusong Yuan, Jianqiao Zheng, Yuchun Sun, Yong Wang, Peijun Lyu
OBJECTIVE: The aim of this study was to assess and regulate heat generation in the dental pulp cavity and circumambient temperature around a tooth during laser ablation with a femtosecond laser in a confined space. BACKGROUND DATA: The automatic tooth preparing technique is one of the traditional oral clinical technology innovations. In this technique, a robot controlled an ultrashort pulse laser to automatically complete the three-dimensional teeth preparing in a confined space...
June 2017: Photomedicine and Laser Surgery
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