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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
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
Sharif Hashmani, Nauman Hashmani, Hina Rajani, Priyanka Ramesh, Junaid Ahmed Soomro, Syed Rashid Hussain Shah, Jaish Kumar, Sayed Mustafa Mahmood Shah
PURPOSE: To compare refractive outcomes, visual acuities, and satisfaction of patients between those treated with laser-assisted in situ keratomileusis (LASIK) using a Hansatome microkeratome (HM) and femto-assisted laser (FAL). METHODS: This was a retrospective analysis of 1,366 eyes in 687 patients who underwent LASIK with an HM (n=1,137) and an FAL (n=229) at the two centers of Hashmanis Hospital, Karachi, Pakistan. Refractive outcomes, including sphere, cylinder, and spherical equivalent in diopters (D), and visual acuities were assessed both preoperatively and at 1 month follow-up...
2017: Clinical Ophthalmology
Lisa Lautner, Kristyna Pluhackova, Nicolai K H Barth, Tilo Seydel, Wiebke Lohstroh, Rainer A Böckmann, Tobias Unruh
Neutron scattering is a powerful tool to study relaxation processes in biological membrane mimics in space and time. Combining different inelastic and quasielastic neutron scattering techniques, a large dynamic range can be covered: from atomic to mesoscopic lengths and from femto- to some hundreds of nanoseconds in time. This allows studies on e.g. the diffusion of lipids, the membrane undulation motions, the dispersion of sound waves in membranes as well as the mutual interactions of membrane constituents such as lipids, proteins, and additives...
June 1, 2017: Chemistry and Physics of Lipids
Avishek Saha, Alicia Moya, Axel Kahnt, Daniel Iglesias, Silvia Marchesan, Reinhold Wannemacher, Maurizio Prato, Juan J Vilatela, Dirk M Guldi
A new insight into photoinduced charge transfer processes across carbon nanotube@TiO2 interfaces has been gained based on experimental details from transient absorption spectroscopy. We show that photoinduced, interfacial hole transfer to carboxylic acid-functionalized multiwalled carbon nanotubes (oxMWCNTs) from TiO2 results in hole-doped oxMWCNTs and reduced TiO2. The latter is inferred from femto- and nanosecond transient absorption spectroscopy performed with oxMWCNT@TiO2 dispersions and complemented with investigations using methyl viologen and N,N,N',N'-tetramethyl-p-phenylenediamine as an electron scavenger and a hole scavenger, respectively...
June 1, 2017: Nanoscale
Martina Ebner, Siegfried Mariacher, Kai Januschowski, Katrin Boden, Anna-Maria Seuthe, Peter Szurman, Karl Thomas Boden
BACKGROUND: To evaluate intraocular pressure (IOP) using the application of a novel liquid patient interface for femtosecond laser-assisted cataract surgery with the FEMTO LDV Z8. METHODS: IOP was evaluated in enucleated porcine eyes prior, during and after the application of the Femto LDV Z8 liquid patient interface (Ziemer Ophthalmic Systems, Switzerland) using intracameral cannulation (n=20), intravitreal cannulation (n=20), rebound tonometry (n=20) and indentation tonometry (n=20)...
May 25, 2017: British Journal of Ophthalmology
Gabriel F Dorlhiac, Clyde Fare, Jasper J van Thor
Ultrafast spectroscopy offers temporal resolution for probing processes in the femto- and picosecond regimes. This has allowed for investigation of energy and charge transfer in numerous photoactive compounds and complexes. However, analysis of the resultant data can be complicated, particularly in more complex biological systems, such as photosystems. Historically, the dual approach of global analysis and target modelling has been used to elucidate kinetic descriptions of the system, and the identity of transient species respectively...
May 2017: PLoS Computational Biology
Alexander S Fokas, Daniel J Cole, Nicholas D M Hine, Stephen A Wells, Michael C Payne, Alex W Chin
Observation of excitonic quantum beats in photosynthetic antennae has prompted wide debate regarding the function of excitonic coherence in pigment-protein complexes. Much of this work focuses on the interactions of excitons with the femto-to-picosecond dynamical fluctuations of their environment. However, in experiments these effects can be masked by static disorder of the excited-state energies across ensembles, whose microscopic origins are challenging to predict. Here the excited-state properties of ∼2000 atom clusters of the Fenna-Matthews-Olson complex are simulated using a unique combination of linear-scaling density functional theory and constrained geometric dynamics...
May 11, 2017: Journal of Physical Chemistry Letters
Yohei Uemura, Daiki Kido, Akihiro Koide, Yuki Wakisaka, Yasuhiro Niwa, Shunsuke Nozawa, Kohei Ichiyanagi, Ryo Fukaya, Shin-Ichi Adachi, Tetsuo Katayama, Tadashi Togashi, Shigeki Owada, Makina Yabashi, Keisuke Hatada, Akihide Iwase, Akihiko Kudo, Satoru Takakusagi, Toshihiko Yokoyama, Kiyotaka Asakura
Ultrafast excitation of photocatalytically active BiVO4 was characterized by femto- and picosecond transient X-ray absorption fine structure spectroscopy. An initial photoexcited state (≪500 fs) changed to a metastable state accompanied by a structural change with a time constant of ∼14 ps. The structural change might stabilize holes on oxygen atoms since the interaction between Bi and O increases.
May 8, 2017: Chemical Communications: Chem Comm
Damien Laage, Thomas Elsaesser, James T Hynes
The structure and function of biomolecules can be strongly influenced by their hydration shells. A key challenge is thus to determine the extent to which these shells differ from bulk water, since the structural fluctuations and molecular excitations of hydrating water molecules within these shells can cover a broad range in both space and time. Recent progress in theory, molecular dynamics simulations, and ultrafast vibrational spectroscopy has led to new and detailed insight into the fluctuations of water structure, elementary water motions, and electric fields at hydrated biointerfaces...
July 2017: Structural Dynamics (Melville, N.Y.)
Avishek Saha, Muqing Chen, Marcus Lederer, Axel Kahnt, Xing Lu, Dirk M Guldi
An unprecedented family of novel electron-donor acceptor conjugates based on fullerenes as electron acceptors, on one hand, and triphenyl amines as electron donors, on the other hand, have been synthesized and characterized in a variety of solvents using steady state absorption/emission as well as transient absorption spectroscopy. These are unprecedented in terms of their outcome of radical ion pair formation, that is, the singlet versus triplet excited state. This was corroborated by femto/nanosecond pump probe experiments and by molecular orbital calculations...
February 1, 2017: Chemical Science
Zubair Shahid Bashir, Muhammad Hassaan Ali, Ayesha Anwar, Muhammad Hammad Ayub, Nadeem Hafeez Butt
Femtosecond laser has been introduced in refractive surgery to create a thin-hinged corneal flap without using any blade. The current review was planned to analyse and compare femtosecond-assisted laser in-situ keratomileusis (LASIK), the latest refractive procedure, with conventional techniques in refractive surgery. The analysis showed that femtosecond-assisted LASIK yielded more predictable corneal flaps, lesser ocular aberrations, better uncorrected visual acuity, lesser variations in intraocular pressure (IOP) and fewer chances of developing dry eyes...
April 2017: JPMA. the Journal of the Pakistan Medical Association
A Balestrazzi, A Balestrazzi, F Menicacci, G Cartocci, F Menicacci, P Michieletto, E Balestrazzi
PurposeTo evaluate the refractive and visual results of one-stage laser-assisted in situ keratomileusis with femtosecond laser (Femto-LASIK) for the correction of residual ametropia after deep anterior lamellar keratoplasty (DALK).MethodsThis retrospective study included 13 eyes of 12 patients, who underwent corneal Femto-LASIK to correct refractive errors after DALK. IntraLase FS150 was used to create a lamellar flap and excimer laser ablation for refractive correction was performed using the Star S4 IR Excimer Laser in eight cases and the Technolas 217z Excimer Laser in Tissue Saving mode in five cases...
April 7, 2017: Eye
Tushar Debnath, Deepa Sebastian, Sourav Maiti, Hirendra N Ghosh
Charge-transfer processes from photoexcited CdSe quantum dots (QDs) to phenol derivatives with electron- donating (4-methoxy) and -withdrawing (4-nitro) moieties have been demonstrated by using steady-state and time- resolved emission and femtosecond transient absorption spectroscopy. Steady-state and time-resolved emission studies suggest that in the presence of both 4-nitrophenol (4NP) and 4-methoxyphenol (4MP) CdSe QDs luminescence is quenched. Stern-Volmer analysis suggests both static and dynamic mechanisms are active for both the QD/phenol composites...
March 27, 2017: Chemistry: a European Journal
Xian-Sheng Ke, Taeyeon Kim, James T Brewster, Vincent M Lynch, Dongho Kim, Jonathan L Sessler
An expanded rosarian (P3P6) with a bowl-like conformation has been prepared and characterized in a one-pot procedure that involves condensing a bispyrrole pyridine precursor (P1P2) with benzaldehyde, followed by oxidation. Single crystal X-ray diffraction analysis reveals a bowl-like conformation in the solid state with an upper rim diameter defined by the meso-phenyl substituents of ca. 13.5 Å and a depth of roughly 6.3 Å. P3P6 forms both 1:1 and 2:1 complexes with C60 in the solid state. DFT reveals similar energies for the two binding modes...
March 24, 2017: Journal of the American Chemical Society
Mingxia Tian, Ping Ma, Guoying Mu
PURPOSE: To compare the visual acuity and contrast sensitivity (CS) after femto laser in situ keratomileusis (fLASIK) and orthokeratology (OK) in patients with low-to-moderate myopia. METHODS: A total of 68 patients were enrolled in this prospective cohort study. Of these, 40 eyes from 40 patients with low-to-moderate myopia underwent fLASIK and 28 eyes from 28 patients underwent OK. In addition to uncorrected distance visual acuity and corrected distance visual acuity, photopic and mesopic CS (with CSV-1000E) were tested before treatment and at 1, 3, and 6 months after treatment...
February 27, 2017: Eye & Contact Lens
Wataru Suzuki, Hiroaki Kotani, Tomoya Ishizuka, Kei Ohkubo, Yoshihito Shiota, Kazunari Yoshizawa, Shunichi Fukuzumi, Takahiko Kojima
Addition of 1 equiv of TFA to an acetone solution containing dodecaphenylporphyrin (H2 DPP) in the presence of 10 % MeOH (v/v) resulted in selective formation of a monoprotonated form (H3 DPP(+) ), in sharp contrast to protonation of H2 DPP directly affording a diprotonated form (H4 DPP(2+) ) in acetone in the absence of MeOH. The crucial role of MeOH for selective H3 DPP(+) formation was interpreted as hydrogen-bonding stabilization of H3 DPP(+) , since a MeOH molecule was found to form hydrogen bonds with an NH proton of H3 DPP(+) in the crystal...
February 7, 2017: Chemistry: a European Journal
B Meyer, K S Kunert
With a rate of less than 2 %, retreatment after SMILE is rare. If a touch-up is required, there are different options to choose from: surface ablation (PRK/LASEK) with Mitomycin C, the standard femto-flap procedure with the same parameters, the CIRCLE procedure, which extends the previous SMILE interface into a flap, or the innovative but off-label capless SMILE procedure, which preserves all the advantages of SMILE.
January 2017: Klinische Monatsblätter Für Augenheilkunde
M F Ciappina, J A Pérez-Hernández, A S Landsman, W A Okell, S Zherebtsov, B Förg, J Schötz, L Seiffert, T Fennel, T Shaaran, T Zimmermann, A Chacón, R Guichard, A Zaïr, J W G Tisch, J P Marangos, T Witting, A Braun, S A Maier, L Roso, M Krüger, P Hommelhoff, M F Kling, F Krausz, M Lewenstein
Recently two emerging areas of research, attosecond and nanoscale physics, have started to come together. Attosecond physics deals with phenomena occurring when ultrashort laser pulses, with duration on the femto- and sub-femtosecond time scales, interact with atoms, molecules or solids. The laser-induced electron dynamics occurs natively on a timescale down to a few hundred or even tens of attoseconds (1 attosecond  =  1 as  =  10(-18) s), which is comparable with the optical field. For comparison, the revolution of an electron on a 1s orbital of a hydrogen atom is  ∼152 as...
May 2017: Reports on Progress in Physics
Evgeni M Glebov, Ivan P Pozdnyakov, Svetlana G Matveeva, Alexei A Melnikov, Sergey V Chekalin, Marina V Rogozina, Vladislav V Yudanov, Vjacheslav P Grivin, Victor F Plyusnin
The photoaquation of the Os(IV)Cl6(2-) complex was studied by means of stationary photolysis, nanosecond laser flash photolysis and ultrafast kinetic spectroscopy. The Os(IV)Cl5(OH)(2-) complex was found to be the only reaction product. The quantum yield of photoaquation is rather low and wavelength-dependent. No impact of redox processes on photoaquation was revealed. The total characteristic lifetime of the process is about 80 ps. Three intermediates were recorded in the femto- and picosecond time domains and assigned to different Os(iv) species...
December 22, 2016: Photochemical & Photobiological Sciences
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