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Intense pulsed light

Valentina Lacivita, Amalia Conte, James G Lyng, Cristina Arroyo, Vittorio A Zambrini, Matteo A Del Nobile
The present study focused on the utilisation of High Intensity Light Pulses (HILP) treatment to preserve mozzarella cheese. First, the susceptibility of Pseudomonas fluorescens and Enterobacteriaceae to HILP (fluences from 0·39 to 28·0 J/cm2) in a transparent liquid was evaluated (in-vitro tests). Afterwards, the effects on inoculated mozzarella cheese were also assessed. Then untreated (Control) and HILP treated samples were packaged and stored at 10 °C for 2 weeks. Enterobacteriaceae, Pseudomonas spp. and pH were monitored during storage...
May 2018: Journal of Dairy Research
Alessandro Agostini, Jens Niklas, Tim Schulte, Marilena Di Valentin, Marco Bortolus, Eckhard Hofmann, Wolfgang Lubitz, Donatella Carbonera
The peridinin-chlorophyll-a protein (PCP) is a water-soluble light harvesting protein of the dinoflagellate Amphidinium carterae, employing peridinin (Per) as the main carotenoid to fulfil light harvesting and photo-protective functions. Per molecules bound to the protein experience specific molecular surroundings which lead to different electronic and spectral properties. In the refolded N89 L variant PCP (N89 L-RFPCP) a significant part of the intensity on the long wavelength side of the absorption spectrum is shifted to shorter wavelengths due to a significant change in the Per-614 site energy...
May 18, 2018: Biochimica et Biophysica Acta
Miguel A Rodríguez, Florian Denis-le Coarer, Ángel Valle
A first analysis of fluctuations of the light intensity of vertical-cavity surface-emitting lasers operating in a bistable regime reveals the presence of 1/f noise. In this regime the intensity fluctuates between two recently characterized states with residence times {τ_{1}} and {τ_{2}}. We identify three distinct processes. One of them presents a coherence enhancement phenomenon, and in the other two the distribution of residence times in one of the states follows either a power law P(τ_{1})∼τ_{1}^{-2} or P(τ_{2})∼τ_{2}^{-2}, and this is the cause of the 1/f shape in the spectral density of the intensity...
April 2018: Physical Review. E
Mihail Simion Beldean-Galea, Florina-Maria Copaciu, Maria-Virginia Coman
The textile industry uses many raw materials (natural and synthetic dyes and fibers) and different dyeing techniques that can be considered important pollutants with a negative impact on the environment (toxic working conditions, discharged wastewater, and contamination). Although synthetic dyes are intensively used, offer a wide range of colors and hues and properties of adhesion, longevity, and resistance to sunshine and chemical processes, and are cost-effective, they have begun to be restricted by many textile producers because they are nonbiodegradable and have toxic, carcinogenic, and mutagenic effects that generate some imbalances in plant, animal, and human life...
May 9, 2018: Journal of AOAC International
Briley Bourgeois, Sijun Luo, Brian Riggs, Yaping Ji, Shiva Adireddy, Kurt Schroder, Stan Farnsworth, Douglas B Chrisey, Matthew Escarra
This work reports a new technique for scalable and low temperature processing of nanostructured-TiO2 thin films, allowing for practical manufacturing of TiO2 based devices such as perovskite solar cells at low temperature or on flexible substrates. Dual layers of dense and mesoporous TiO2/graphitic oxide nanocomposite films are synthesized simultaneously using inkjet printing and pulsed photonic irradiation. Investigation of process parameters including precursor concentration (10-20 wt%) and exposure fluence (4...
May 8, 2018: Nanotechnology
Tamás Szidarovszky, Gabor J Halasz, Attila G Császár, Lorenz S Cederbaum, Agnes Vibok
Rovibronic spectra of the field-dressed homonuclear diatomic Na2 molecule is in- vestigated to identify direct signatures of the light-induced conical intersection (LICI) on the spectrum. The theoretical framework formulated allows the computation of the (1) field-dressed rovibronic states induced by a medium intensity continuous-wave laser light and the (2) transition amplitudes between these field-dressed states with respect to an additional weak probe pulse. The field-dressed spectrum features ab- sorption peaks resembling the field-free spectrum as well as stimulated emission peaks corresponding to transitions not visible in the field-free case...
May 7, 2018: Journal of Physical Chemistry Letters
Hiroyuki Katsuki, Nobuyuki Takei, Christian Sommer, Kenji Ohmori
Coherent control is a technique to manipulate wave functions of matter with light. Coherent control of isolated atoms and molecules in the gas phase is well-understood and developed since the 1990s, whereas its application to condensed matter is more difficult because its coherence lifetime is shorter. We have recently applied this technique to condensed matter samples, one of which is solid para-hydrogen ( p-H2 ). Intramolecular vibrational excitation of solid p-H2 gives an excited vibrational wave function called a "vibron", which is delocalized over many hydrogen molecules in a manner similar to a Frenkel exciton...
May 7, 2018: Accounts of Chemical Research
F Langer, C P Schmid, S Schlauderer, M Gmitra, J Fabian, P Nagler, C Schüller, T Korn, P G Hawkins, J T Steiner, U Huttner, S W Koch, M Kira, R Huber
As conventional electronics approaches its limits 1 , nanoscience has urgently sought methods of fast control of electrons at the fundamental quantum level 2 . Lightwave electronics 3 -the foundation of attosecond science 4 -uses the oscillating carrier wave of intense light pulses to control the translational motion of the electron's charge faster than a single cycle of light5-15 . Despite being particularly promising information carriers, the internal quantum attributes of spin 16 and valley pseudospin17-21 have not been switchable on the subcycle scale...
May 2018: Nature
David Rand, Marie Jakešová, Gur Lubin, Ieva Vėbraitė, Moshe David-Pur, Vedran Đerek, Tobias Cramer, Niyazi Serdar Sariciftci, Yael Hanein, Eric Daniel Głowacki
An efficient nanoscale semiconducting optoelectronic system is reported, which is optimized for neuronal stimulation: the organic electrolytic photocapacitor. The devices comprise a thin (80 nm) trilayer of metal and p-n semiconducting organic nanocrystals. When illuminated in physiological solution, these metal-semiconductor devices charge up, transducing light pulses into localized displacement currents that are strong enough to electrically stimulate neurons with safe light intensities. The devices are freestanding, requiring no wiring or external bias, and are stable in physiological conditions...
May 2, 2018: Advanced Materials
Daniel J Heath, Taimoor H Rana, Rupert A Bapty, James A Grant-Jacob, Yunhui Xie, Robert W Eason, Ben Mills
Subtractive femtosecond laser machining using multiple pulses with different spatial intensity profiles centred on the same position on a sample has been used to fabricate surface relief structuring. A digital micromirror device was used as an intensity spatial light modulator, with a fixed position relative to the sample, to ensure optimal alignment between successive masks. Up to 50 distinct layers, 335 nm lateral spatial resolution and 2.6 µm maximum depth structures were produced. The lateral dimensions of the structures are approximately 40 µm...
April 30, 2018: Optics Express
Raphaël Florentin, Vincent Kermene, Agnès Desfarges-Berthelemot, Alain Barthelemy
Ultrashort light pulse transport and amplification in a 1.3 m long step-index multimode fiber with gain and with weak coupling has been investigated. An adaptive shaping of the input wavefront, only based on the output intensity pattern, has led to an amplified pulse focused both in space (1/32) and in time (1/10) despite a strong modal group delay dispersion. Optimization of the input owing to the two-photon detection of the amplified signal permitted to excite the fastest and more intense principal mode of the fiber and to get an output pulse duration limited by group velocity dispersion...
April 16, 2018: Optics Express
Yingzi Zhang, Yulong Hou, Yanjun Zhang, Yanjun Hu, Liang Zhang, Xiaolong Gao, Huixin Zhang, Wenyi Liu
A quasi-distributed liquid leakage (QDLL) sensor in local area is proposed and experimentally demonstrated, providing a real-time yet low-cost method than the existing local QDLL sensor. The sensor mainly consists of a flexible lamp belt (FLB) with light-emitting diodes (LEDs) and a polymer optical fiber (POF) processed with side-coupling structures. The side-coupling structures are illuminated by the LEDs one by one, forming a series of sensing probes. The lights are side-coupled into the POF through the side-coupling structure and pulse sequences are obtained from the power meters connected to the both ends of the POF...
April 16, 2018: Optics Express
Zhaokun Wang, D N Wang, Fan Yang, Liujiang Li, Chun-Liu Zhao, Ben Xu, Shangzhong Jin, Shi-Ying Cao, Zhan-Jun Fang
A novel mode-locking method based on the nonlinear multimode interference in the stretched graded-index multimode optical fiber (GIMF) is proposed in this Letter. The simple device geometry, where the light is coupled in and out of the stretched GIMF via single-mode fibers, is demonstrated to exhibit the temporal intensity discrimination required for mode locking. The nonlinear saturable absorber (SA) characteristics of the device are controllable by simply adjusting the strength of the stretching applied. The modulation depth of the device, which consists of ∼23...
May 1, 2018: Optics Letters
Dongliang Lin, Fang Zhang, Weilin Cheng, Huijie Huang
Trapezoidal illumination is an effective approach to improve the integrated uniformity of light intensity in a step-and-scan lithographic system. When different laser pulses are utilized, the optimal trapezoidal illumination varies. In addition, if the coherence factor takes different values, the outline of the trapezoidal illumination varies as well, directly affecting the integrated uniformity of light intensity. To reduce the impact of variations in trapezoidal illumination, a newly designed method for generating arbitrary trapezoidal illuminations using variable slits is proposed...
April 10, 2018: Applied Optics
Bei Rong, Yun Tang, Ping Tu, Ruixing Liu, Jing Qiao, Wenjing Song, Rolando Toyos, Xiaoming Yan
OBJECTIVE: To determine the efficacy and safety of intense pulsed light (IPL) applied directly on the eyelids and meibomian gland expression (MGX) in treating meibomian gland dysfunction (MGD). BACKGROUND: IPL application on the periocular skin effectively improves meibomian gland secretion and tear film break-up time (TBUT) in patients with MGD/dry eye. METHODS: This prospective, randomized, double-masked, controlled study involved 44 patients...
April 24, 2018: Photomedicine and Laser Surgery
Hao Huang, Hongfeng Tang, Meiling Huang, Xiufen Zheng, Ruihua Wang, Yong Hu, Wenyi Lv
The effect of and the optimal parameters for intense pulsed light (IPL) with a 420-nm filter on an isolate of the fungus Trichophyton rubrum (T. rubrum) were examined in vitro. Colonies of T. rubrum were irradiated by using 420-nm IPL with various pulse numbers and energies. Colony areas were photographed and compared with those of untreated colonies to assess growth inhibition. Statistically significant inhibition of T. rubrum growth was detected in colonies treated with 12 pulses of greater than or equal to 12 J/cm2 ...
April 23, 2018: Lasers in Medical Science
Haizhou Ren, Farooq Khurum Shehzad, Yunshan Zhou, Lijuan Zhang, Arshad Iqbal, Yi Long
Herein, new all-inorganic transparent composite films with the formula (Zn2Al-LDH/{Mo132-Ac})n have been fabricated by a layer-by-layer method using the exfoliated Zn2Al-LDH monolayer nanosheets and Keplerate-type macroanion {Mo132-Ac}. They were characterized by UV-vis absorption spectroscopy, SEM, AFM, and XPS techniques. The Z-scan measurements, which were conducted under laser irradiation at a wavelength of 532 nm, a pulse width of 6 ns, a repetition rate of 10 Hz, and the light intensity at a focus E0 of 10 μJ, revealed that all the films had notable saturated absorption and self-defocusing effect with a large third-order optical nonlinear susceptibility χ(3)...
April 19, 2018: Dalton Transactions: An International Journal of Inorganic Chemistry
Ajay J Deshpande
Background: Acne vulgaris is a self-limiting, chronic inflammatory disorder of the pilosebaceous unit characterized by exacerbations and remissions. It is often the early manifestation of puberty, and in girls it appears relatively early. In women, acne tends to become aggravated during the menstrual period, pregnancy, and in those who are on progesterone. Acne treatment is divided into two parts: topical and systemic. For Grades 1 and 2 acne, topical treatment is sufficient, while for Grades 3 and 4 acne, systemic drugs such as tetracyclines and retinoids are required to control the symptoms...
April 2018: Journal of Clinical and Aesthetic Dermatology
Fabrizio Preda, Antonio Perri, Julien Réhault, Biplab Dutta, Jan Helbing, Giulio Cerullo, Dario Polli
We introduce a novel configuration for the broadband measurement of the optical activity of molecules, combining time-domain detection with heterodyne amplification. A birefringent common-path polarization-division interferometer creates two phase-locked replicas of the input light with orthogonal polarization. The more intense replica interacts with the sample, producing a chiral free-induction decay field, which interferes with the other replica, acting as a time-delayed phase-coherent local oscillator. By recording the delay-dependent interferogram, we obtain by a Fourier transform both the circular dichroism and circular birefringence spectra...
April 15, 2018: Optics Letters
Bryan P Yan, William H S Lai, Christy K Y Chan, Stephen Chun-Hin Chan, Lok-Hei Chan, Ka-Ming Lam, Ho-Wang Lau, Chak-Ming Ng, Lok-Yin Tai, Kin-Wai Yip, Olivia T L To, Ben Freedman, Yukkee C Poh, Ming-Zher Poh
BACKGROUND: We aimed to evaluate a novel method of atrial fibrillation (AF) screening using an iPhone camera to detect and analyze photoplethysmographic signals from the face without physical contact by extracting subtle beat-to-beat variations of skin color that reflect the cardiac pulsatile signal. METHODS AND RESULTS: Patients admitted to the cardiology ward of the hospital for clinical reasons were recruited. Simultaneous facial and fingertip photoplethysmographic measurements were obtained from 217 hospital inpatients (mean age, 70...
April 5, 2018: Journal of the American Heart Association
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