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Wen-Hsuan Kuan, Li-Ting Kao, Jing-Yun Wang, Kuei-Huei Lin
We report a passively mode-locked erbium-doped fiber laser with pulse widths switchable from 473 fs to 76.8 ns, where the fundamental mode-locking, noise-like pulse, nanosecond mode-locking, and dual-width mode-locking (DML) are obtained by adjusting a polarization controller. Co-existence of femto- and nano-second pulses in DML is attributed to the gain balancing. Analytic modeling of the fiber laser with the cubic-quintic Ginzburg-Landau equation is presented, in which the pulse widths are calculated as functions of dispersion, self-phase modulation (SPM), cubic saturable absorption (SA), and quintic SA...
January 15, 2018: Optics Letters
K Dirian, S Bauroth, A Roth, Z Syrgiannis, F Rigodanza, M Burian, H Amenitsch, D I Sharapa, M Prato, T Clark, D M Guldi
The aggregation and the photophysics of a water soluble perylenediimide (PDI) derivative that features two bromine substituents in the bay positions has been probed. Non-fluorescent aggregates were found to be present at concentrations of 1.0 × 10-5 M. In situ small-angle X-ray scattering (SAXS) measurements and complementary molecular modeling showed the presence of PDI aggregates. In their singlet excited states, the PDI aggregates are characterized by distinct transient fingerprints and rapid deactivation, as revealed by pump-probe experiments on the femto-, pico-, nano-, and microsecond timescales...
January 12, 2018: Nanoscale
Anna Zieleniewska, Shannon Harper, Dennis Arnold, Dirk Michael Guldi
At the focal point of this work was photophysical characterization of three meso-meso two-atom-bridged diporphyrins (1-3). Detailed investigations by means of cyclic voltammetry, absorption, fluorescence, and femto-/nano-second transient absorption spectroscopy revealed the discrepancy in electronic communication in a series of meso-meso two-atom-bridged porphyrins in the ground state and in the excited state. In the ground state, the azo-bridge facilitates the strongest electronic communication between the two porphyrins...
January 4, 2018: Chemistry: a European Journal
Min-Ji Kang, Yong-Eun Lee, Jun-Sub Choi, Choun-Ki Joo
In femtosecond laser-assisted cataract surgery, the parameter such as horizontal spot spacing and energy level can be adjusted. Although there have been several studies reported on various laser systems, showing the effects of varying energy levels and horizontal spot spacing on lens capsulotomy cut edges, none have been reported on the Catalys laser system (Abbott Medical Optics, Inc., Santa Ana, CA). The aim of this study is to evaluate, using scanning electron microscopy (SEM), the quality of the cut edges of the laser lens capsulotomy obtained using the Catalys Laser System, using different horizontal spot spacing and energy levels, and to determine the ideal parameters based on SEM results...
2018: PloS One
Yusaku Hontani, Matthias Broser, Arita Silapetere, Benjamin S Krause, Peter Hegemann, John T M Kennis
Anion channelrhodopsins (ACRs) are of great interest due to their ability to inhibit electrical signaling in optogenetic experiments. The photochemistry of ACRs is currently poorly understood and an improved understanding would be beneficial for rational design of ACRs with modified properties. Activation/deactivation of ACRs involves a series of photoreactions ranging from femtoseconds to seconds, thus real-time observation is essential to comprehend the full complexity of the photochemical processes. Here we investigate the photocycle of an ACR from Proteomonas sulcata (PsACR1), which is valuable for optogenetic applications due to the red-shifted absorption and action spectra compared to the prototype ACRs from Guillardia theta: GtACR1 and GtACR2, and the fast channel closing properties...
November 22, 2017: Physical Chemistry Chemical Physics: PCCP
Taito Osaka, Takashi Hirano, Yuki Morioka, Yasuhisa Sano, Yuichi Inubushi, Tadashi Togashi, Ichiro Inoue, Kensuke Tono, Aymeric Robert, Kazuto Yamauchi, Jerome B Hastings, Makina Yabashi
Temporal coherence is one of the most fundamental characteristics of light, connecting to spectral information through the Fourier transform relationship between time and frequency. Interferometers with a variable path-length difference (PLD) between the two branches have widely been employed to characterize temporal coherence properties for broad spectral regimes. Hard X-ray interferometers reported previously, however, have strict limitations in their operational photon energies, due to the specific optical layouts utilized to satisfy the stringent requirement for extreme stability of the PLD at sub-ångström scales...
November 1, 2017: IUCrJ
Zhenjie Wu, Rui Yang, Di Zu, Shuqing Sun
The development of highly sensitive and rapid methods for detecting DNA is of critical importance. Here, we describe a strategy for the digital detection of target DNA at the femto-molar level. Individual DNA molecules were encoded with a single gold nanorod (AuNR), separated and enriched by magnetic immune-separation. The coding gold nanorods were then de-hybridized and dispersed into a gold nanosphere (AuNS) solution at a certain concentration, and both gold nanoparticles were immobilized on glass slides for dark-field microscopic imaging...
November 7, 2017: Scientific Reports
Suhee Kim, Jeong Won Park, Alastair W Wark, Sung Hwa Jhung, Hye Jin Lee
The multiplexed detection of protein biomarkers in plasma present over a range of clinically relevant concentrations continues to be difficult for surface-based bioaffinity detection platforms such as surface plasmon resonance (SPR). As well as nonspecific adsorption, challenges include quantitative comparison between targets whose concentrations differ by orders of magnitude, regenerating SPR chips after plasma exposure, and the two- or four-channel limitation of many commercial SPR instruments limiting sample throughput...
November 7, 2017: Analytical Chemistry
Mohammad Ghoreishi, Afsaneh Naderi Beni, Zahra Naderi Beni, Alireza Zandi, Farzan Kianersi
The purpose of this study is to compare visual outcomes of myopic refractive surgery, using tissue saving (TS), a standard ablation profile by a Technolas 217z100, and aberration smart ablation (ASA), an aspheric algorithm by a MEL 80 excimer laser in two eyes of one patient. In this prospective interventional paired-eye controlled study, a total of 100 eyes of 50 participants with myopia with or without astigmatism underwent thin-flap Femto-LASIK, using a Femto LDV femtosecond laser (Ziemer Ophthalmic Systems AG, Port, Switzerland)...
December 2017: Lasers in Medical Science
Jing Zhang, Yue-Hua Zhou, Yan Zheng, Qian Liu
AIM: To compare the speed of visual recovery following myopic thin-flap LASIK with four femtosecond lasers. METHODS: Eighty-eight eyes of 46 patients who were consecutively scheduled for bilateral LASIK with the IntraLase FS60 (Group 1), Femto LDV Crystal Line (Group 2), Wavelight FS200 (Group 3) and VisuMax (Group 4) femtosecond lasers were enrolled in. Monocular uncorrected distance visual acuity (UDVA), best-corrected distant visual acuity (CDVA), refraction, contrast sensitivity and higher-order aberrations (HOAs) were evaluated at 1, 3d, 1wk and 1mo postoperatively...
2017: International Journal of Ophthalmology
Apeng Chen, Kyle B Lynch, Jiangtao Ren, Zhijian Jia, Yu Yang, Joann J Lu, Shaorong Liu
Single-cell analysis has attracted increasing attention because of cell heterogeneities. Various strategies have been developed for analyzing single cells, but most of these analytical processes kill the cells. Tools that can qualitatively and quantitatively measure the cellular contents without killing the cell are highly demanding because they enable us to conduct single-cell time-course studies (e.g., to examine how a cell responds to a therapy before, during, and after a treatment). Here we develop a femto-liter (fL) pipet to serve this purpose...
October 4, 2017: Analytical Chemistry
Maria Carmina Scala, Marina Sala, Agostina Pietrantoni, Antonia Spensiero, Simone Di Micco, Mariangela Agamennone, Alessia Bertamino, Ettore Novellino, Giuseppe Bifulco, Isabel M Gomez-Monterrey, Fabiana Superti, Pietro Campiglia
Bovine lactoferrin is a biglobular multifunctional iron binding glycoprotein that plays an important role in innate immunity against infections. We have previously demonstrated that selected peptides from bovine lactoferrin C-lobe are able to prevent both Influenza virus hemagglutination and cell infection. To deeper investigate the ability of lactoferrin derived peptides to inhibit Influenza virus infection, in this study we identified new bovine lactoferrin C-lobe derived sequences and corresponding synthetic peptides were synthesized and assayed to check their ability to prevent viral hemagglutination and infection...
September 6, 2017: Scientific Reports
Yulin Lei, Jie Hou, Xiuyun Zheng
Objective Decentered flaps are rarely reported after femtosecond laser-assisted in situ keratomileusis flap procedures. We present a patient with a decentered flap after preparation of a corneal flap using the Femto LDV technique. Methods The 22-year-old man required a redo operation because of a decentered corneal flap. It was performed the same day at the patient's insistence and with his consent. The new corneal flap for the redo surgery was prepared using the femtosecond laser technique and IntraLase. Results Uncorrected visual acuity for each eye was 1...
January 1, 2017: Journal of International Medical Research
Mohammad Ghoreishi, Zahra Naderi Beni, Afsaneh Naderi Beni, Farzan Kianersi
PURPOSE: To compare the visual and refractive outcomes after FEMTOLASIK with and without iris registration. METHODS: In this randomized, prospective, comparative, contralateral eye study, 118 eyes of 59 patients with myopia and myopic astigmatism underwent LASIK using the Femto LDV femtosecond laser (160 µm) and the MEL80 with or without iris registration. For each patient, iris registration FEMTOLASIK was performed on one eye and non-iris registration FEMTOLASIK was performed on the other eye, assigned at random...
September 5, 2017: International Ophthalmology
Kaitlin T Wozniak, Noah Elkins, Daniel R Brooks, Daniel E Savage, Scott MacRae, Jonathan D Ellis, Wayne H Knox, Krystel R Huxlin
Blue-intra-tissue refractive index shaping (Blue-IRIS) is a new approach to laser refractive correction of optical aberrations in the eye, which alters the refractive index of the cornea rather than changing its shape. Before it can be implemented in humans, it is critical to establish whether and to what extent, Blue-IRIS damages the cornea. Here, we contrasted the impact of -1.5 D cylinder refractive corrections inscribed using either Blue-IRIS or femtosecond laser in-situ keratomileusis (femto-LASIK) on corneal cell viability...
August 31, 2017: Experimental Eye Research
Maciej Dąbrowski, Yanan Dai, Hrvoje Petek
Experimental methods for ultrafast microscopy are advancing rapidly. Promising methods combine ultrafast laser excitation with electron-based imaging or rely on super-resolution optical techniques to enable probing of matter on the nano-femto scale. Among several actively developed methods, ultrafast time-resolved photoemission electron microscopy provides several advantages, among which the foremost are that time resolution is limited only by the laser source and it is immediately capable of probing of coherent phenomena in solid-state materials and surfaces...
September 6, 2017: Journal of Physical Chemistry Letters
Hassan Sabbah, Anthony Bonnamy, Dimitris Papanastasiou, Jose Cernicharo, Jose-Angel Martín-Gago, Christine Joblin
We developed a new analytical experimental setup called AROMA (Astrochemistry Research of Organics with Molecular Analyzer) that combines laser desorption/ionization techniques with ion trap mass spectrometry. We report here on the ability of the apparatus to detect aromatic species in complex materials of astrophysical interests and characterize their structures. A limit of detection of 100 femto-grams has been achieved using pure polycyclic aromatic hydrocarbon (PAH) samples, which corresponds to 2x10(8) molecules in the case of coronene (C24H12)...
July 1, 2017: Astrophysical Journal
Meng Zhou, Chenjie Zeng, Matthew Y Sfeir, Mircea Cotlet, Kenji Iida, Katsuyuki Nobusada, Rongchao Jin
Understanding the correlation between the atomic structure and optical properties of gold nanoclusters is essential for exploration of their functionalities and applications involving light harvesting and electron transfer. We report the femto-nanosecond excited state dynamics of a periodic series of face-centered cubic (FCC) gold nanoclusters (including Au28, Au36, Au44, and Au52), which exhibit a set of unique features compared with other similar sized clusters. Molecular-like ultrafast Sn → S1 internal conversions (i...
August 15, 2017: Journal of Physical Chemistry Letters
Mohamed Hosny, Fayrouz Aboalazayem, Hoda El Shiwy, Mohsen Salem
PURPOSE: The purpose of the study was to determine the accuracy of intraocular pressure (IOP) measurement after small incision lenticule extraction (SMILE) using Goldmann applanation tonometry (GAT) and ocular response analyzer (ORA). METHODS: This is a prospective clinical study that was conducted on 30 eyes in the interval between February 2016 and September 2016. The age of the patients ranged between 19 and 40 years. The patients underwent SMILE surgery using the femto laser...
2017: Clinical Ophthalmology
Maximilian Wolf, Astrid Herrmann, Andreas Hirsch, Dirk M Guldi
Porphyrin arrays consisting of three peripheral Zinc porphyrins (ZnPs) and a central free base porphyrin (H2P)-all rigidly linked to each other-serve as light-harvesting antennas as well as electron donors and are flexibly coupled to an electron-accepting C60 to realize the unidirectional flow of (i) excited-state energy from the ZnPs at the periphery to the H2P, (ii) electrons to C60, and (iii) holes to H2P and, subsequently, to ZnP. Dynamics following photoexcitation are elucidated by time-resolved transient absorption measurements on the femto-, pico-, nano-, and microsecond time scales and are examined by multiwavelength as well as target analyses...
August 15, 2017: Journal of the American Chemical Society
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