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Thomas P Nicholls, Johnathon C Robertson, Michael G Gardiner, Alex C Bissember
It has been reported that pulsed irradiation can improve photosynthetic activity and phytochemical production in plants. Intrigued and inspired by these observations, we postulated that pulsed irradiation strategies may have broader implications in organic synthesis. We report here the results of a proof-of-concept study demonstrating that pulsed LED irradiation enhances the efficiency of a visible light-mediated photoredox-catalysed reaction. The design and construction of an inexpensive multiphase circuit (∼US$5) enabling power and pulse frequency modulation, which is connected to light-emitting diodes (LEDs), provides a source of pulsed visible light...
April 19, 2018: Chemical Communications: Chem Comm
E Priglinger, J Maier, S Chaudary, C Lindner, C Wurzer, S Rieger, H Redl, S Wolbank, P Dungel
A highly interesting source for adult stem cells is adipose tissue, from which the stromal vascular fraction (SVF) - a heterogeneous cell population including the adipose-derived stromal/stem cells (ASC) - can be obtained. To enhance the regenerative potential of freshly isolated SVF cells low level light therapy (LLLT), was used. The effects of pulsed blue (475 nm), green (516 nm) and red light (635 nm) from light-emitting diodes (LEDs) applied on freshly isolated SVF were analyzed regarding cell phenotype, cell number, viability, adenosine triphosphate content, cytotoxicity and proliferation, but also osteogenic, adipogenic and pro-angiogenic differentiation potential...
March 31, 2018: Journal of Tissue Engineering and Regenerative Medicine
Sandra González-Casado, Olga Martín-Belloso, Pedro Elez-Martínez, Robert Soliva-Fortuny
The application of pulsed electric fields (PEFs) to whole tomatoes is proposed as a pre-processing treatment to obtain purees with high health-related properties. Tomato fruit was subjected to different electric field strengths (0.4, 1.2 and 2 kV cm-1) and number of pulses (5, 18 and 30 pulses). Tomatoes were stored at 4 °C for 24 h after PEF processing and then ground and mixed with 5% olive oil. The resulting tomato-based product was subjected to in vitro gastrointestinal digestion. PEF treatments significantly increased the amount and bioaccessible fraction of carotenoids in the derived product...
March 21, 2018: Food & Function
Sara V Tadayon, Elizabeth S Foreman, Craig Murray
Reactions of the simplest Criegee intermediate (CH2 OO) with a series of alcohols have been studied in a flash photolysis flow reactor. Laser photolysis of diiodomethane at 355 nm in the presence of molecular oxygen was used to produce CH2 OO, and the absolute number densities were determined as a function of delay time from analysis of broadband transient absorption spectra obtained using a pulsed LED. The kinetics for the reactions of CH2 OO with methanol, ethanol, and 2-propanol were measured under pseudo-first-order conditions at 295 K, yielding rate constants of (1...
January 11, 2018: Journal of Physical Chemistry. A
Sabrina Rohringer, Wolfgang Holnthoner, Sidrah Chaudary, Paul Slezak, Eleni Priglinger, Martin Strassl, Karoline Pill, Severin Mühleder, Heinz Redl, Peter Dungel
Low level light therapy receives increasing interest in the fields of tissue regeneration and wound healing. Several in vivo studies demonstrated the positive effects of LLLT on angiogenesis. This study aimed to investigate the underlying properties in vitro by comparing the effects of light therapy by light emitting diodes of different wavelengths on endothelial cells in vitro. Human umbilical vein endothelial cells were treated with either 475 nm, 516 nm or 635 nm light. Control cells were not illuminated...
September 6, 2017: Scientific Reports
Kristian J Sexton, Yan Zhao, Scott C Davis, Shudong Jiang, Brian W Pogue
The design of fluorescence imaging instruments for surgical guidance is rapidly evolving, and a key issue is to efficiently capture signals with high ambient room lighting. Here, we introduce a novel time-gated approach to fluorescence imaging synchronizing acquisition to the 120 Hz light of the room, with pulsed LED excitation and gated ICCD detection. It is shown that under bright ambient room light this technique allows for the detection of physiologically relevant nanomolar fluorophore concentrations, and in particular reduces the light fluctuations present from the room lights, making low concentration measurements more reliable...
May 1, 2017: Biomedical Optics Express
François-Xavier Joly, Kelsey L Kurupas, Heather L Throop
Macroclimate has traditionally been considered the predominant driver of litter decomposition. However, in drylands, cumulative monthly or annual precipitation typically fails to predict decomposition. In these systems, the windows of opportunity for decomposer activity may rather depend on the precipitation frequency and local factors affecting litter desiccation, such as soil-litter mixing. We used a full-factorial microcosm experiment to disentangle the relative importance of cumulative precipitation, pulse frequency, and soil-litter mixing on litter decomposition...
June 19, 2017: Ecology
Andres A Aguirre-Pablo, Meshal K Alarfaj, Er Qiang Li, J F Hernández-Sánchez, Sigurdur T Thoroddsen
We demonstrate the viability of using four low-cost smartphone cameras to perform Tomographic PIV. We use colored shadows to imprint two or three different time-steps on the same image. The back-lighting is accomplished with three sets of differently-colored pulsed LEDs. Each set of Red, Green & Blue LEDs is shone on a diffuser screen facing each of the cameras. We thereby record the RGB-colored shadows of opaque suspended particles, rather than the conventionally used scattered light. We subsequently separate the RGB color channels, to represent the separate times, with preprocessing to minimize noise and cross-talk...
June 16, 2017: Scientific Reports
Viktorija Vaštakaitė, Akvilė Viršilė, Aušra Brazaitytė, Giedrė Samuolienė, Julė Jankauskienė, Algirdas Novičkovas, Pavelas Duchovskis
A novel research of pulsed light-emitting diode (LED) lighting versus continuous lighting was conducted by analyzing phytochemical levels in microgreens. Red pak choi (Brassica rapa var. chinensis), mustard (Brassica juncea L.), and tatsoi (Brassica rapa var. rosularis) were grown indoors under HPS lamps supplemented with monochromatic (455, 470, 505, 590, and 627 nm) LEDs [total photosynthetic photon flux density (PPFD) of 200 ± 10 μmol m(-2) s(-1), for 16 h day(-1)]. For pulsed light treatments, the frequencies at 2, 32, 256, and 1024 Hz with a duty cycle of 50% monochromatic LEDs were applied...
August 9, 2017: Journal of Agricultural and Food Chemistry
Kimio Hirabayashi, Yoshinari Nagai, Tetsuya Mushya, Makoto Higashino, Yoshio Taniguchi
A study on the attraction of adult Propsilocerus akamusi midges to different-colored light traps was carried out from October 21 to November 15, 2013. The 6 colored lights used in light-emitting diode (LED) lamps were white, green, red, blue, amber, and ultraviolet (UV). The UV lamp attracted the most P. akamusi, followed by green, white, blue, amber, and red. A white pulsed LED light attracted only half the number of midges as did a continuous-emission white LED light. The result indicated that manipulation of light color, considering that the red LED light and/or pulsed LED light are not as attractive as the other colors, may be appropriate for the development of an overall integrated strategy to control nuisance P...
June 2017: Journal of the American Mosquito Control Association
Raquel Galante, Daniela Ghisleni, Patrizia Paradiso, Vitor D Alves, Terezinha J A Pinto, Rogério Colaço, Ana Paula Serro
Sterilization of hydrogels is challenging due to their often reported sensitivity to conventional methods involving heat or radiation. Although aseptic manufacturing is a possibility, terminal sterilization is safer in biological terms, leading to a higher overall efficiency, and thus should be used whenever it is possible. The main goal of this work was to study the applicability of an innovative ozone gas terminal sterilization method for silicone-based hydrogels and compare its efficacy and effects with those of traditional sterilization methods: steam heat and gamma irradiation...
September 1, 2017: Materials Science & Engineering. C, Materials for Biological Applications
Hui Liu, Yu Cao, Wei Li, Zhao Zhang, Erik Jeppesen, Wei Wang
Pulse inputs of heavy metals are expected to increase with a higher frequency of extreme climate events (heavy rain), leading to stronger erosion of contaminated and fertilized farmland soils to freshwaters, with potentially adverse effects on lake ecosystems. We conducted a 5-month mesocosm study to elucidate the responses of the submerged macrophyte Vallisneria spinulosa and phytoplankton to four different doses of cadmium (Cd): 0 (control), 0.05, 0.5, and 5 g m-2 (CK, I, II, and III, respectively) under mesotrophic conditions...
June 2017: Environmental Science and Pollution Research International
Yuriana Aguilar-Sanchez, Diego Fainstein, Rafael Mejia-Alvarez, Ariel L Escobar
In the heart, molecular signaling studies are usually performed in isolated myocytes. However, many pathological situations such as ischemia and arrhythmias can only be fully understood at the whole organ level. Here, we present the spectroscopic technique of local field fluorescence microscopy (LFFM) that allows the measurement of cellular signals in the intact heart. The technique is based on a combination of a Langendorff perfused heart and optical fibers to record fluorescent signals. LFFM has various applications in the field of cardiovascular physiology to study the heart under normal and pathological conditions...
March 8, 2017: Journal of Visualized Experiments: JoVE
J Rösner, A Liotta, E A Angamo, C Spies, U Heinemann, R Kovács
Dynamic alterations in flavin adenine dinucleotide (FAD) fluorescence permit insight into energy metabolism-dependent changes of intramitochondrial redox potential. Monitoring FAD fluorescence in living tissue is impeded by photobleaching, restricting the length of microfluorimetric recordings. In addition, photodecomposition of these essential electron carriers negatively interferes with energy metabolism and viability of the biological specimen. Taking advantage of pulsed LED illumination, here we determined the optimal excitation settings giving the largest fluorescence yield with the lowest photobleaching and interference with metabolism in hippocampal brain slices...
July 1, 2016: Journal of Microscopy
Sheraz Hussain, Mohammad Faizan Zahid, Arshalooz Jamila Rahman, Mehnaz Atiq Ahmed, Shahnaz Hamid Ibrahim
Mumps is an acute viral illness that follows a self-limiting course but up to 10% of cases have a complicated course with the involvement of other organ systems. Myocarditis is reported as a complication but the incidence has greatly fallen ever since the development of the mumps vaccine. A child presented to our department with parotid swelling and fever. Persistent tachycardia with irregular pulse led to further cardiac work up which showed decreased ejection fraction and raised serum cardiac enzymes, indicating myocardial damage...
January 2016: Journal of Ayub Medical College, Abbottabad: JAMC
Muath Nairat, Arkaprabha Konar, Vadim V Lozovoy, Warren F Beck, G J Blanchard, Marcos Dantus
Fast population transfer from higher to lower excited states occurs via internal conversion (IC) and is the basis of Kasha's rule, which states that spontaneous emission takes place from the lowest excited state of the same multiplicity. Photonic control over IC is of interest because it would allow direct influence over intramolecular nonradiative decay processes occurring in condensed phase. Here we tracked the S2 and S1 fluorescence yield for different cyanine dyes in solution as a function of linear chirp...
March 24, 2016: Journal of Physical Chemistry. A
Patrick Steiner, Andreas Ebneter, Lieselotte Erika Berger, Martin Zinkernagel, Boris Považay, Christoph Meier, Jens H Kowal, Carsten Framme, Ralf Brinkmann, Sebastian Wolf, Raphael Sznitman
PURPOSE: Selective retina therapy (SRT) is a novel treatment for retinal pathologies, solely targeting the RPE. During SRT, the detection of an immediate tissue reaction is challenging, as tissue effects remain limited to intracellular RPE photodisruption. Time-resolved ultra-high axial resolution optical coherence tomography (OCT) is thus evaluated for the monitoring of dynamic optical changes at and around the RPE during SRT. METHODS: An experimental OCT system with an ultra-high axial resolution of 1...
October 2015: Investigative Ophthalmology & Visual Science
S Chaudray, J Zipperle, A Islam, M Nimmervoll, L Karner, H Redl, S Bahrami, P Dungel
INTRODUCTION: Low-level light therapy (LLLT) is clinically used to attenuate inflammation and improve tissue repair processes. We aimed to evaluate the effects of red LED light on inflammatory response in a whole blood in vitro model as well as in isolated granulocytes. METHODS: Human whole blood was stimulated with 1ng/ml LPS for 4 h. Pulsed LED light (632 nm) was applied either 1 h or 4 h after LPS for 10 min. Granulocytes were stimulated with PMA or fMLP respectively, and treated with LED-light likewise...
October 2015: Shock
W Kyle Mitchell, Bethan E Phillips, John P Williams, Debbie Rankin, Jonathan N Lund, Daniel J Wilkinson, Kenneth Smith, Philip J Atherton
Essential amino acids (EAA) are responsible for skeletal muscle anabolic effects after nutrient intake. The pattern of appearance of EAA in blood, e.g., after intake of "slow" or "fast" protein sources or in response to grazing vs. bolus feeding patterns, may impact anabolism. However, the influence of this on muscle anabolism is poorly understood, particularly in older individuals. We determined the effects of divergent feeding profiles of EAA on blood flow, anabolic signaling, and muscle protein synthesis (MPS) in older men...
September 1, 2015: American Journal of Physiology. Endocrinology and Metabolism
Jinmyoung Joo, Xiangyou Liu, Venkata Ramana Kotamraju, Erkki Ruoslahti, Yoonkey Nam, Michael J Sailor
The luminescence lifetime of nanocrystalline silicon is typically on the order of microseconds, significantly longer than the nanosecond lifetimes exhibited by fluorescent molecules naturally present in cells and tissues. Time-gated imaging, where the image is acquired at a time after termination of an excitation pulse, allows discrimination of a silicon nanoparticle probe from these endogenous signals. Because of the microsecond time scale for silicon emission, time-gated imaging is relatively simple to implement for this biocompatible and nontoxic probe...
June 23, 2015: ACS Nano
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