keyword
MENU ▼
Read by QxMD icon Read
search

Femtosecond laser

keyword
https://www.readbyqxmd.com/read/29147002/capturing-an-initial-intermediate-during-the-p450nor-enzymatic-reaction-using-time-resolved-xfel-crystallography-and-caged-substrate
#1
Takehiko Tosha, Takashi Nomura, Takuma Nishida, Naoya Saeki, Kouta Okubayashi, Raika Yamagiwa, Michihiro Sugahara, Takanori Nakane, Keitaro Yamashita, Kunio Hirata, Go Ueno, Tetsunari Kimura, Tamao Hisano, Kazumasa Muramoto, Hitomi Sawai, Hanae Takeda, Eiichi Mizohata, Ayumi Yamashita, Yusuke Kanematsu, Yu Takano, Eriko Nango, Rie Tanaka, Osamu Nureki, Osami Shoji, Yuka Ikemoto, Hironori Murakami, Shigeki Owada, Kensuke Tono, Makina Yabashi, Masaki Yamamoto, Hideo Ago, So Iwata, Hiroshi Sugimoto, Yoshitsugu Shiro, Minoru Kubo
Time-resolved serial femtosecond crystallography using an X-ray free electron laser (XFEL) in conjunction with a photosensitive caged-compound offers a crystallographic method to track enzymatic reactions. Here we demonstrate the application of this method using fungal NO reductase, a heme-containing enzyme, at room temperature. Twenty milliseconds after caged-NO photolysis, we identify a NO-bound form of the enzyme, which is an initial intermediate with a slightly bent Fe-N-O coordination geometry at a resolution of 2...
November 17, 2017: Nature Communications
https://www.readbyqxmd.com/read/29141390/-the-clinical-analysis-of-corneal-interface-fluid-syndrome-after-laser-lamellar-corneal-refractive-surgery
#2
K J Lin, J Chen, W Lin, X D Lin, Y M Zhou, L D Zheng, Y Tong
Objective: To analysis, the clinical characteristics, refractive changes, and clinical treatment of interface fluid syndrome after laser lamellar corneal refractive surgery. Methods: During Dec. 2010 to Apr. 2016. In total 6 cases(9 eyes), 3 cases were bilateral, 3 cases were unilateral. Five patients were male and 1 was female. The age of the patients ranged from 20 to 29 years was (24.83±4.02) years. Six cases(9 eyes)of IFS were diagnosed at our hospital. The history and complete ophthalmic examination that include Slit-lamp examination, Slit-lamp photography, refraction, corneal thickness measurement, corneal endothelial cell counting, IOP, anterior segment OCT(AS-OCT), exams were recorded...
November 11, 2017: [Zhonghua Yan Ke za Zhi] Chinese Journal of Ophthalmology
https://www.readbyqxmd.com/read/29140363/snapshot-second-harmonic-generation-polarimeter-based-on-spectral-analysis
#3
Matthieu Dubreuil, Sylvain Rivet, Yann Le Grand
A new high-speed second-harmonic generation (SHG) polarimetric method is reported. It is based on the spectral analysis of the SHG radiation emitted by a nonlinear medium excited with circularly polarized femtosecond laser pulses. The setup uses only passive components for polarization encoding and a fast spectrometer for spectral analysis. The method is validated on a z-cut quartz plate, then on a collagen-rich biological tissue with a view to single image polarization-resolved SHG microscopy.
November 15, 2017: Optics Letters
https://www.readbyqxmd.com/read/29140361/self-referenced-octave-wide-subharmonic-gap-optical-parametric-oscillator-centered-at-3%C3%A2-%C3%A2-%C3%AE-m-and-pumped-by-an-er-fiber-laser
#4
Qitian Ru, Zachary E Loparo, XiaoSheng Zhang, Sean Crystal, Subith Vasu, Peter G Schunemann, Konstantin L Vodopyanov
We report an octave-wide mid-IR spectrum (2.3-4.8 μm) obtained from a subharmonic optical parametric oscillator (OPO) based on a newly developed nonlinear crystal, orientation-patterned gallium phosphide (OP-GaP), which was synchronously pumped by a femtosecond 1560 nm fiber laser. We proved that the octave-wide output is in the form of a single frequency comb. The observed f-to-2f frequency beats, originating directly from the OPO, can be used for self-referencing and phase locking of the pump laser comb with no need for supercontinuum generation...
November 15, 2017: Optics Letters
https://www.readbyqxmd.com/read/29140359/ns-duration-transient-bragg-gratings-in-silica-fibers
#5
Avishay Shamir, Aviran Halstuch, Yonatan Sivan, Amiel A Ishaaya
We demonstrate, for the first time to our knowledge, fast all-optical switching in standard silica fibers, based on a transient Bragg grating. The grating is implemented in the fiber using an immunization photo-pretreatment process, followed by side illumination with femtosecond laser pulses through a suitable phase mask. Each pulse is nonlinearly absorbed, creating a thermal grating that is washed out by thermal diffusion. Reflections measured from such gratings are characterized by a very fast rise time, nanoseconds duration, and a high extinction ratio...
November 15, 2017: Optics Letters
https://www.readbyqxmd.com/read/29140342/fiber-format-dual-comb-coherent-raman-spectrometer
#6
Nicola Coluccelli, Christopher R Howle, Kenneth McEwan, Yuchen Wang, Toney Teddy Fernandez, Alessio Gambetta, Paolo Laporta, Gianluca Galzerano
We demonstrate a fiber-format system for dual-comb coherent anti-Stokes Raman scattering spectroscopy. The system is based on two ytterbium fiber (Yb) femtosecond lasers at repetition frequencies of 94 MHz, a Yb amplifier, and a photonic crystal fiber for spectral broadening and generation of pulses with a central wavelength of 1040 nm and durations in the sub-20-fs regime. We observed Raman spectra of acetonitrile and ethyl acetate with spectral coverage from 100 to 1300  cm(-1), resolution of 8  cm(-1), and a signal-to-noise ratio of around 100, when averaging over 10 acquisitions...
November 15, 2017: Optics Letters
https://www.readbyqxmd.com/read/29140334/carrier-envelope-offset-stabilization-of-a-ghz-repetition-rate-femtosecond-laser-using-opto-optical-modulation-of-a-sesam
#7
Sargis Hakobyan, Valentin J Wittwer, Kutan Gürel, Aline S Mayer, Stéphane Schilt, Thomas Südmeyer
We demonstrate, to the best of our knowledge, the first carrier-envelope offset (CEO) frequency stabilization of a GHz femtosecond laser based on opto-optical modulation (OOM) of a semiconductor saturable absorber mirror (SESAM). The 1.05-GHz laser is based on a Yb:CALGO gain crystal and emits sub-100-fs pulses with 2.1-W average power at a center wavelength of 1055 nm. The SESAM plays two key roles: it starts and stabilizes the mode-locking operation and is simultaneously used as an actuator to control the CEO frequency...
November 15, 2017: Optics Letters
https://www.readbyqxmd.com/read/29137707/use-of-chemical-conversion-for-determination-of-nitrated-aromatic-hydrocarbons-using-femtosecond-ionization-mass-spectrometry
#8
Takuya Fujii, Tomoko Imasaka, Totaro Imasaka
A sample containing nitrated aromatic hydrocarbons (NPAHs) was injected into the sample inlet port of a gas chromatograph (GC), along with hydrazine, a reducing reagent. The analytes that eluted from the GC column were measured by mass spectrometry (MS) using an ultraviolet femtosecond laser as the ionization source. When no reducing reagent was used, large numbers of polycyclic aromatic hydrocarbons (PAHs) including NPAHs were observed in the two-dimensional GC/MS display. In contrast, when hydrazine was present, reduced forms of NPAHs, which included amino PAHs, were detected...
December 15, 2017: Analytica Chimica Acta
https://www.readbyqxmd.com/read/29134403/femtosecond-lenticule-extraction-performed-on-a-wrong-meridian-and-effectively-reversed-by-excimer-laser-ablation
#9
Alper Agca, Yusuf Yildirim, Burçin Kepez Yildiz, Dilek Yasa, Ali Demircan, Ahmet Demirok
No abstract text is available yet for this article.
November 13, 2017: Lasers in Medical Science
https://www.readbyqxmd.com/read/29131161/rapid-virtual-hematoxylin-and-eosin-histology-of-breast-tissue-specimens-using-a-compact-fluorescence-nonlinear-microscope
#10
Lucas C Cahill, Michael G Giacomelli, Tadayuki Yoshitake, Hilde Vardeh, Beverly E Faulkner-Jones, James L Connolly, Chi-Kuang Sun, James G Fujimoto
Up to 40% of patients undergoing breast conserving surgery for breast cancer require repeat surgeries due to close to or positive margins. The lengthy processing required for evaluating surgical margins by standard paraffin-embedded histology precludes its use during surgery and therefore, technologies for rapid evaluation of surgical pathology could improve the treatment of breast cancer by reducing the number of surgeries required. We demonstrate real-time histological evaluation of breast cancer surgical specimens by staining specimens with acridine orange (AO) and sulforhodamine 101 (SR101) analogously to hematoxylin and eosin (H&E) and then imaging the specimens with fluorescence nonlinear microscopy (NLM) using a compact femtosecond fiber laser...
November 13, 2017: Laboratory Investigation; a Journal of Technical Methods and Pathology
https://www.readbyqxmd.com/read/29124264/laser-structured-janus-wire-mesh-for-efficient-oil-water-separation
#11
Yu-Qing Liu, Dong-Dong Han, Zhi-Zhen Jiao, Yan Liu, Hao-Bo Jiang, Xuan-Hang Wu, Hong Ding, Yong-Lai Zhang, Hong-Bo Sun
We report here the fabrication of a Janus wire mesh by a combined process of laser structuring and fluorosilane/graphene oxide (GO) modification of the two sides of the mesh, respectively, toward its applications in efficient oil/water separation. Femtosecond laser processing has been employed to make different laser-induced periodic surface structures (LIPSS) on each side of the mesh. Surface modification with fluorosilane on one side and GO on the other side endows the two sides of the Janus mesh with distinct wettability...
November 10, 2017: Nanoscale
https://www.readbyqxmd.com/read/29123680/hit-detection-in-serial-femtosecond-crystallography-using-x-ray-spectroscopy-of-plasma-emission
#12
H Olof Jönsson, Carl Caleman, Jakob Andreasson, Nicuşor Tîmneanu
Serial femtosecond crystallography is an emerging and promising method for determining protein structures, making use of the ultrafast and bright X-ray pulses from X-ray free-electron lasers. The upcoming X-ray laser sources will produce well above 1000 pulses per second and will pose a new challenge: how to quickly determine successful crystal hits and avoid a high-rate data deluge. Proposed here is a hit-finding scheme based on detecting photons from plasma emission after the sample has been intercepted by the X-ray laser...
November 1, 2017: IUCrJ
https://www.readbyqxmd.com/read/29123676/merging-single-shot-xfel-diffraction-data-from-inorganic-nanoparticles-a-new-approach-to-size-and-orientation-determination
#13
Xuanxuan Li, John C H Spence, Brenda G Hogue, Haiguang Liu
X-ray free-electron lasers (XFELs) provide new opportunities for structure determination of biomolecules, viruses and nanomaterials. With unprecedented peak brilliance and ultra-short pulse duration, XFELs can tolerate higher X-ray doses by exploiting the femtosecond-scale exposure time, and can thus go beyond the resolution limits achieved with conventional X-ray diffraction imaging techniques. Using XFELs, it is possible to collect scattering information from single particles at high resolution, however particle heterogeneity and unknown orientations complicate data merging in three-dimensional space...
November 1, 2017: IUCrJ
https://www.readbyqxmd.com/read/29123375/sequential-keraring-implantation-and-corneal-cross-linking-for-the-treatment-of-keratoconus-in-children-with-vernal-keratoconjunctivitis
#14
Mortada A Abozaid
Purpose: The purpose of this study was to assess the safety and efficacy of femtosecond laser-assisted Keraring implantation followed by transepithelial accelerated corneal collagen cross-linking (CXL) for the treatment of keratoconus in children with vernal keratoconjunctivitis (VKC). Study design: This is a prospective interventional non-comparative case series. Patients and methods: Eighteen eyes of 11 children with keratoconus and VKC were included in this study...
2017: Clinical Ophthalmology
https://www.readbyqxmd.com/read/29121878/comparison-of-femtosecond-laser-assisted-corneal-intrastromal-xenotransplantation-and-the-allotransplantation-in-rhesus-monkeys
#15
He Jin, Liangping Liu, Hui Ding, Miao He, Chi Zhang, Xingwu Zhong
BACKGROUND: In our previous study, we showed that both allogeneic and autogeneic small-incision femtosecond laser-assisted corneal intrastromal transplantation are safe and effective surgeries. However, the results of small-incision femtosecond laser-assisted intrastromal xenotransplantation have not yet been explored. Additionally, we suggest that glycerol-dehydrated corneal lamellae might provide a possible alternative for this xenogenic implantation approach. METHODS: Corneal inlay lamellae were produced from rabbits and humans using femtosecond laser-assisted surgeries and were dehydrated in glycerol for 1 week at 4 °C...
November 9, 2017: BMC Ophthalmology
https://www.readbyqxmd.com/read/29120720/advanced-cataract-learning-experience-in-united-states-ophthalmology-residency-programs
#16
Adam J Yen, Saras Ramanathan
This study examined resident exposure to and competency in new techniques for cataract removal and intraocular lens (IOL) implantation. A questionnaire was sent to 116 United States ophthalmology program directors and completed by 71. In response to the questionnaire, program directors reported that 95.3% of their graduating seniors were competent to select and implant toric IOLs and 52.3% were competent to implant capsular tension rings (CTRs). Divide and conquer (56.6%) and stop and chop (25.4%) dominated phacoemulsification teaching...
October 2017: Journal of Cataract and Refractive Surgery
https://www.readbyqxmd.com/read/29120718/wound-healing-in-rabbit-corneas-after-flapless-refractive-lenticule-extraction-with-a-345%C3%A2-nm-ultraviolet-femtosecond-laser
#17
Christian M Hammer, Corinna Petsch, Jörg Klenke, Katrin Skerl, Christian Wüllner, Christof Donitzky, Friedrich Paulsen, Michael Scholz, Theo Seiler, Friedrich E Kruse, Johannes Menzel-Severing
PURPOSE: To characterize corneal wound healing in a rabbit model after flapless refractive lenticule extraction with a 345 nm ultraviolet femtosecond laser. SETTING: Departments of Ophthalmology and Anatomy II, University of Erlangen-Nürnberg and Wavelight GmbH, Erlangen, Germany. DESIGN: Experimental study. METHODS: Flapless refractive lenticule extraction was performed in 1 eye each of 20 New Zealand white rabbits (-5...
October 2017: Journal of Cataract and Refractive Surgery
https://www.readbyqxmd.com/read/29120710/femtosecond-laser-implantation-of%C3%A2-a%C3%A2-340-degree-intrastromal-corneal-ring%C3%A2-segment-in-keratoconus-short-term%C3%A2-outcomes
#18
Mohammad Mehdi Sadoughi, Bahram Einollahi, Amir Reza Veisi, Mohammad Zare, Mohammad Reza Sedaghat, Danial Roshandel, Neda Einollahi, Javad Rezaei
PURPOSE: To evaluate the short-term outcomes of femtosecond laser-assisted implantation of a 340-degree intracorneal ring (ICR) (Keraring) in patients with keratoconus. SETTING: Four centers in Iran. DESIGN: Prospective case series. METHODS: All cases had implantation of the 340-degree ICR after tunnel creation with a femtosecond laser. The uncorrected (UDVA) and corrected (CDVA) distance visual acuities, sphere, cylinder, manifest refraction spherical equivalent (MRSE), mean keratometry (K), steep K, and flat K were evaluated preoperatively and 1, 3, and 6 months postoperatively...
October 2017: Journal of Cataract and Refractive Surgery
https://www.readbyqxmd.com/read/29120645/coherent-two-quantum-two-dimensional-electronic-spectroscopy-using-incoherent-light
#19
Darin James Ulness, Daniel B Turner
Two-quantum two-dimensional electronic spectroscopy (2Q 2D ES) may provide a measure of electron-correlation energies in molecules. Attempts to obtain this profound but elusive signal have relied on experimental implementations using femtosecond laser pulses, which induce an overwhelming background signal of nonresonant response. Here we explore theoretically the signatures of electron correlation in coherent 2Q 2D ES measurements that use spectrally incoherent light, I(4) 2Q 2D ES. One can use such fields to suppress nonresonant response, and therefore this method may better isolate the desired signature of electron correlation...
November 9, 2017: Journal of Physical Chemistry. A
https://www.readbyqxmd.com/read/29120231/impact-of-clear-corneal-incision-morphology-on-incision-site-descemet-membrane-detachment-in-conventional-and-femtosecond-laser-assisted-phacoemulsification
#20
Jeewan S Titiyal, Manpreet Kaur, Priyanka Ramesh, Pooja Shah, Ruchita Falera, Lalit M S Bageshwar, Ashutosh Kinkar, Namrata Sharma
PURPOSE: To assess intraoperative morphology of clear corneal incisions (CCI) and its impact on incision-site descemet membrane detachment (DMD) in conventional phacoemulsification and femtosecond laser-assisted cataract surgery (FLACS). METHODS: Prospective comparative study of 129 eyes that underwent either conventional phacoemulsification (Group I, n = 77) or FLACS (Group II, n = 52) was undertaken at an apex tertiary care ophthalmic setup. In group I, a 2...
November 9, 2017: Current Eye Research
keyword
keyword
31972
1
2
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read
×

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"