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https://www.readbyqxmd.com/read/28059773/attosecond-physics-at-the-nanoscale
#1
Marcelo F Ciappina, J Perez-Hernandez, Alexandra Landsman, William Okell, Sergey Zherebtsov, Benjamin Förg, Johannes Schötz, Lennart Seiffert, Thomas Fennel, Tahir Shaaran, Tomas Zimmermann, Alexis Chacón, Roland Guichard, Amelle Zair, John Tisch, J Marangos, Tobias Witting, Avi Braun, Stefan Maier, Luis Roso, Michael Krüger, Peter Hommelhoff, Matthias Kling, Ferenc Krausz, Maciej 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, 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...
January 6, 2017: Reports on Progress in Physics
https://www.readbyqxmd.com/read/28009886/primary-photophysical-and-photochemical-processes-for-hexachloroosmate-iv-in-aqueous-solution
#2
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
https://www.readbyqxmd.com/read/28006678/rapid-and-sensitive-detection-of-bisphenol-a-from-serum-matrix
#3
Xiaogang Lin, Cheng Cheng, Paul Terry, Jiangang Chen, Haochen Cui, Jayne Wu
Bisphenol A (BPA) is an endocrine disrupting compound that may have adverse developmental, reproductive, neurological, and immune system effects. Low-level exposure to BPA is ubiquitous in human populations due to its widespread use in consumer products. Therefore, highly sensitive methods are needed to quantify BPA in various matrices including water, serum, and food products. In this study, we developed a simple, rapid, highly sensitive and specific sensor based on an aptamer probe and AC electrokinetics capacitive sensing method that successfully detected BPA at femto molar (fM) levels, which is an improvement over prior work by a factor of 10...
December 10, 2016: Biosensors & Bioelectronics
https://www.readbyqxmd.com/read/27957338/comparison-of-the-optical-quality-between-small-incision-lenticule-extraction-and-femtosecond-laser-lasik
#4
Ying Jin, Yan Wang, Lulu Xu, Tong Zuo, Hua Li, Rui Dou, Jiamei Zhang
Purpose. To investigate the visual quality after SMILE and Femto-LASIK. Methods. About 123 eyes from 63 patients were enrolled in this study. The parameters were measured preoperatively and 1 week, 1 month, and 3 months postoperatively using Sirius System. Results. The MTF curve increase slightly from low to high frequency at 3 mm and 6 mm pupil diameter after SMILE surgery (P < 0.05) during the follow-up time comparing with the preoperative values. And the SR has a significant increase at various pupil diameters as well (P < 0...
2016: Journal of Ophthalmology
https://www.readbyqxmd.com/read/27911101/in-vivo-and-ex-vivo-evaluation-of-inflammation-and-apoptosis-induced-after-smile-procedures-for-different-refractive-error-range
#5
Leonardo Mastropasqua, Roberta Calienno, Claudia Curcio, Rodolfo Mastropasqua, Mario Nubile, Niccolò Salgari, Manuela Lanzini
PURPOSE: To detect corneal inflammation and apoptosis induced after small incision lenticule extraction (SMILE) at different refractive corrections for moderate to high values of myopia. METHODS: Fifty patients (50 eyes) suffering from medium to high myopia (spherical equivalent refraction from -3.75 to -10.00 diopters (D) with refractive astigmatism under -0.75 D) underwent SMILE in order to correct myopic error. In vivo evaluation was done by corneal confocal microscopy (IVCM) and ex vivo by immunohistochemistry...
December 2, 2016: Current Eye Research
https://www.readbyqxmd.com/read/27828513/hybrid-cavity-coupled-plasmonic-biosensors-for-low-concentration-label-free-and-selective-biomolecular-detection
#6
Abraham Vázquez-Guardado, Alexandra Smith, Wade Wilson, Jeanette Ortega, J Manuel Perez, Debashis Chanda
Simple optical techniques that can accurately and selectively identify organic and inorganic material in a reproducible manner are of paramount importance in biological sensing applications. In this work, we demonstrate that a nanoimprinted plasmonic pattern with locked-in dimensions supports sharp deterministic hybrid resonances when coupled with an optical cavity suitable for high sensitive surface detection. The surface sensing property of this hybrid system is quantified by precise atomic layer growth of aluminum oxide using the atomic layer deposition technique...
October 31, 2016: Optics Express
https://www.readbyqxmd.com/read/27827917/analytical-study-on-multi-tier-5g-heterogeneous-small-cell-networks-coverage-performance-and-energy-efficiency
#7
Zhu Xiao, Hongjing Liu, Vincent Havyarimana, Tong Li, Dong Wang
In this paper, we investigate the coverage performance and energy efficiency of multi-tier heterogeneous cellular networks (HetNets) which are composed of macrocells and different types of small cells, i.e., picocells and femtocells. By virtue of stochastic geometry tools, we model the multi-tier HetNets based on a Poisson point process (PPP) and analyze the Signal to Interference Ratio (SIR) via studying the cumulative interference from pico-tier and femto-tier. We then derive the analytical expressions of coverage probabilities in order to evaluate coverage performance in different tiers and investigate how it varies with the small cells' deployment density...
November 4, 2016: Sensors
https://www.readbyqxmd.com/read/27801688/current-and-effective-advantages-of-femto-phacoemulsification
#8
Ashvin Agarwal, Soosan Jacob
PURPOSE OF REVIEW: The purpose is to review the current and effective advantages of femtosecond laser-assisted cataract surgery (FLACS). RECENT FINDINGS: FLACS has advantages over manual phacoemulsification in its precision, and predictability and may be especially advantageous in difficult situations such as shallow anterior chamber, subluxated cataracts, white cataracts, and so on. However, the femtosecond capsulorhexis may not be as strong as a manual rhexis...
January 2017: Current Opinion in Ophthalmology
https://www.readbyqxmd.com/read/27768809/heteroleptic-copper-photosensitizers-why-an-extended-%C3%AF-system-does-not-automatically-lead-to-enhanced-hydrogen-production
#9
Martin Heberle, Stefanie Tschierlei, Nils Rockstroh, Mark Ringenberg, Wolfgang Frey, Henrik Junge, Matthias Beller, Stefan Lochbrunner, Michael Karnahl
A series of heteroleptic copper(I) photosensitizers of the type [(P^P)Cu(N^N)](+) with an extended π-system in the backbone of the diimine ligand has been prepared. The structures of all complexes are completely characterized by NMR spectroscopy, mass spectrometry, and X-ray crystallography. These novel photosensitizers were assessed with respect to the photocatalytic reduction of protons in the presence of triethylamine and [Fe3 (CO)12 ]. Although the solid-state structures and computational results show no significant impact of the π-extension on the structural properties, decreased activities were observed...
October 21, 2016: Chemistry: a European Journal
https://www.readbyqxmd.com/read/27699605/femtosecond-laser-assisted-lasik-versus-prk-for-high-myopia-comparison-of-18-month-visual-acuity-and-quality
#10
Hassan Hashemi, Reza Ghaffari, Mohammad Miraftab, Soheila Asgari
PURPOSE: To compare 18-month outcomes between femtosecond laser-assisted LASIK (femto-LASIK) and photorefractive keratectomy with mitomycin-C (PRK-MMC) for myopia of more than 7.0 D in terms of visual acuity and quality. METHODS: In this comparative nonrandomized clinical trial, 60 eyes from 30 patients (30 eyes in each group) were enrolled. The two procedures were compared in terms of 18-month changes in uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), manifest refraction spherical equivalent, ocular and corneal higher order aberrations (HOAs), and contrast sensitivity (CS)...
October 3, 2016: International Ophthalmology
https://www.readbyqxmd.com/read/27699099/optofluidic-chips-with-nanochannels-for-dynamic-molecular-detection-using-enhanced-fluorescence
#11
P A Postigo, R Alvaro, A Juarros, S Merino
The fabrication of a novel optofluidic chip using nanochannels optimized for DNA-stretched molecules and optical detection by enhanced fluorescence is reported. The chips are composed of a series of microchannels that allow the transport of molecules in the femto-liter per second inside a fluid or gas. The nanochannels are surrounded by a photonic crystal structure to enhance the emission of fluorescent light from the molecules, which can travel along the nanochannel, allowing for enhanced optical detection of the molecules in motion...
September 1, 2016: Biomedical Optics Express
https://www.readbyqxmd.com/read/27643602/-experience-with-introduction-of-smile-learning-phase-of-our-first-200-treatments
#12
S Taneri, S Kießler, A Rost, B Dick
Background: Small Incision Lenticule Extraction (SMILE) is a relatively new surgical method to correct myopia and myopic astigmatism. Although considered to be safe and effective, it is not yet popular. Potential reasons for its limited use could be that surgeons fear inferior results and a higher complication rate in the learning phase. Therefore we present our experiences with the treatment of our first 200 eyes, with special attention to refraction results, complications, and learning curve. Patients and Methods: 200 myopic or myopic astigmatic eyes of 102 patients were treated with SMILE...
September 19, 2016: Klinische Monatsblätter Für Augenheilkunde
https://www.readbyqxmd.com/read/27623280/microscale-loop-mediated-isothermal-amplification-of-viral-dna-with-real-time-monitoring-on-solution-gated-graphene-fet-microchip
#13
Dawoon Han, Rohit Chand, Yong-Sang Kim
Rapid and reliable molecular analysis of DNA for disease diagnosis is highly sought-after. FET-based sensors fulfill the demands of future point-of-care devices due to its sensitive charge sensing and possibility of integration with electronic instruments. However, most of the FETs are unstable in aqueous conditions, less sensitive and requires conventional Ag/AgCl electrode for gating. In this work, we propose a solution-gated graphene FET (SG-FET) for real-time monitoring of microscale loop-mediated isothermal amplification of DNA...
September 4, 2016: Biosensors & Bioelectronics
https://www.readbyqxmd.com/read/27555334/reversible-fmn-dissociation-from-escherichia-coli-respiratory-complex-i
#14
Peter J Holt, Rouslan G Efremov, Eiko Nakamaru-Ogiso, Leonid A Sazanov
Respiratory complex I transfers electrons from NADH to quinone, utilizing the reaction energy to translocate protons across the membrane. It is a key enzyme of the respiratory chain of many prokaryotic and most eukaryotic organisms. The reversible NADH oxidation reaction is facilitated in complex I by non-covalently bound flavin mononucleotide (FMN). Here we report that the catalytic activity of E. coli complex I with artificial electron acceptors potassium ferricyanide (FeCy) and hexaamineruthenium (HAR) is significantly inhibited in the enzyme pre-reduced by NADH...
November 2016: Biochimica et Biophysica Acta
https://www.readbyqxmd.com/read/27550793/the-photochemistry-of-sodium-ion-pump-rhodopsin-observed-by-watermarked-femto-to-submillisecond-stimulated-raman-spectroscopy
#15
Yusaku Hontani, Keiichi Inoue, Miroslav Kloz, Yoshitaka Kato, Hideki Kandori, John T M Kennis
Krokinobacter rhodopsin 2 (KR2) is a recently discovered light-driven Na(+) pump that holds significant promise for application as a neural silencer in optogenetics. KR2 transports Na(+) (in NaCl solution) or H(+) (in larger cation solution, e.g. in CsCl) during its photocycle. Here, we investigate the photochemistry of KR2 with the recently developed watermarked, baseline-free femto- to submillisecond transient stimulated Raman spectroscopy (TSRS), which enables us to investigate retinal chromophore dynamics in real time with high spectral resolution over a large time range...
September 21, 2016: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/27531291/femtosecond-laser-assisted-cataract-surgery-first-clinical-results-with-special-regard-to-central-corneal-thickness-endothelial-cell-count-and-aqueous-flare-levels
#16
Siegfried Mariacher, Martina Ebner, Anna-Maria Seuthe, Kai Januschowski, Ciprian Ivanescu, Natalia Opitz, Peter Szurman, Karl Thomas Boden
PURPOSE: To evaluate clinical data and outcomes after femtosecond laser-assisted cataract surgery with the recently introduced low-energy Femto LDV Z8 laser during a 3-month follow-up. SETTING: Knappschaft Eye Clinic Sulzbach, Knappschaft Hospital Saar GmbH, Sulzbach, Germany. DESIGN: Consecutive case series. METHODS: Femtosecond laser-assisted cataract surgery was performed using the low-energy femtosecond laser. Clinical data including objective refraction, corrected distance visual acuity, central corneal thickness (CCT), endothelial cell count (ECC), and aqueous flare were evaluated 1 day, 1 week, 4 weeks, and 3 months postoperatively...
August 2016: Journal of Cataract and Refractive Surgery
https://www.readbyqxmd.com/read/27516155/a-high-energy-charge-separated-state-of-1-70%C3%A2-ev-from-a-high-potential-donor-acceptor-dyad-a-catalyst-for-energy-demanding-photochemical-reactions
#17
Gary N Lim, Christopher O Obondi, Francis D'Souza
A high potential donor-acceptor dyad composed of zinc porphyrin bearing three meso-pentafluorophenyl substituents covalently linked to C60 , as a novel dyad capable of generating charge-separated states of high energy (potential) has been developed. The calculated energy of the charge-separated state was found to be 1.70 eV, the highest reported for a covalently linked porphyrin-fullerene dyad. Intramolecular photoinduced electron transfer leading to charge-separated states of appreciable lifetimes in polar and nonpolar solvents has been established from studies involving femto- to nanosecond transient absorption techniques...
September 12, 2016: Angewandte Chemie
https://www.readbyqxmd.com/read/27494682/-lasik-and-femto-lasik
#18
T Schlote, M Kynigopoulos
No abstract text is available yet for this article.
August 5, 2016: Klinische Monatsblätter Für Augenheilkunde
https://www.readbyqxmd.com/read/27466066/all-optical-switching-in-granular-ferromagnets-caused-by-magnetic-circular-dichroism
#19
Matthew O A Ellis, Eric E Fullerton, Roy W Chantrell
Magnetic recording using circularly polarised femto-second laser pulses is an emerging technology that would allow write speeds much faster than existing field driven methods. However, the mechanism that drives the magnetisation switching in ferromagnets is unclear. Recent theories suggest that the interaction of the light with the magnetised media induces an opto-magnetic field within the media, known as the inverse Faraday effect. Here we show that an alternative mechanism, driven by thermal excitation over the anisotropy energy barrier and a difference in the energy absorption depending on polarisation, can create a net magnetisation over a series of laser pulses in an ensemble of single domain grains...
2016: Scientific Reports
https://www.readbyqxmd.com/read/27456563/-riboflavin-photoprotection-with-cross-linking-effect-in-photorefractive-ablation-of-the-cornea
#20
I M Kornilovsky, A I Sultanova, A A Burtsev
UNLABELLED: Photorefractive ablation is inevitably accompanied by oxidative stress of the cornea and weakening of its biomechanical and photoprotective properties. AIM: To validate the expediency of riboflavin use in photorefractive ablation for photoprotection of the cornea and cross-linking. MATERIAL AND METHODS: The effects of riboflavin use in photorefractive ablation was first studied in a series of in vitro and in vivo experiments performed on 56 eyes of 28 rabbits, and then on 232 eyes of 142 patients with different degrees of myopia...
May 2016: Vestnik Oftalmologii
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