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https://www.readbyqxmd.com/read/29041257/giant-optical-nonlinearity-in-dna-lyotropic-liquid-crystals
#1
Liana Lucchetti, Tommaso P Fraccia, Fabrizio Ciciulla, Francesco Simoni, Tommaso Bellini
We report the experimental evidence of nonlinear optical response in DNA lyotropic nematic liquid crystals. Pump-probe experiments indicate that the non-linearity is remarkably large. Quantitative assessment of the non-linear optical coefficient by transient optical grating demonstrates that the response is of the same order of the well-known Giant Optical Nonlinearity (GON) of thermotropic nematics. These results represent a further incentive to the current investigation of potential applications of DNA in biophotonics...
October 16, 2017: Optics Express
https://www.readbyqxmd.com/read/29029977/spontaneous-luminescence-color-change-in-the-firefly-luciferase-assay-system
#2
Pei-Han Liu, Pawel L Urban
The temporal effects of luciferase reaction luminescence have only been discussed in the context of light intensity (flash vs. glow). However, alterations in the color of the light emitted over the course of the luciferase reaction have not been reported. Here, we show a temporal change in the light color emitted during the reaction catalyzed by unmodified firefly luciferase when concentrations of one of the substrates, adenosine triphosphate (ATP), are gradually increased. The temporal color change from green to red occurs within the first few minutes of the luciferase reaction when an ATP-containing solution is either added or synthesized in situ with the aid of an autocatalytic reaction occurring simultaneously...
October 10, 2017: Analytical Biochemistry
https://www.readbyqxmd.com/read/29027407/challenges-in-translation-models-to-promote-translation
#3
Jürgen Popp, Dennis Matthews, Alfredo Martinez-Coll, Thomas Mayerhöfer, Brian C Wilson
We first discuss the main obstacles for clinical translation of biophotonics technologies, in particular, the different valleys of death, after which we present different examples of ways to bridge these gaps, remove the obstacles, and promote clinical translation.
October 2017: Journal of Biomedical Optics
https://www.readbyqxmd.com/read/29024604/the-avian-embryo-as-a-model-for-fetal-alcohol-spectrum-disorders
#4
Susan M Smith, George R Flentke
Prenatal alcohol exposure (PAE) remains a leading preventable cause of structural birth defects and permanent neurodevelopmental disability. The chick (Gallus gallus domesticus) is a powerful embryological research model and was possibly the first (Fere, 1895) in which alcohol's teratogenicity was demonstrated. Pharmacologically relevant alcohol exposures in the range of 20-70 mM (20-80 mg/egg) disrupt chick embryo growth, morphogenesis, and behavior, and the resulting phenotypes strongly parallel those of mammalian models...
October 12, 2017: Biochemistry and Cell Biology, Biochimie et Biologie Cellulaire
https://www.readbyqxmd.com/read/28981999/special-section-guest-editorial-advanced-laser-technologies-for-biophotonics
#5
Martin Leahy, Tia Keyes, Valery Tuchin, Alexander Priezzhev
This guest editorial introduces the special section on Advanced Laser Technologies for Biophotonics.
September 27, 2017: Journal of Biomedical Optics
https://www.readbyqxmd.com/read/28969095/mechanisms-of-phosphenes-in-irradiated-patients
#6
REVIEW
Thibaud Mathis, Stephane Vignot, Cecila Leal, Jean-Pierre Caujolle, Celia Maschi, Martine Mauget-Faÿsse, Laurent Kodjikian, Stéphanie Baillif, Joel Herault, Juliette Thariat
Anomalous visual perceptions have been reported in various diseases of the retina and visual pathways or can be experienced under specific conditions in healthy individuals. Phosphenes are perceptions of light in the absence of ambient light, occurring independently of the physiological and classical photonic stimulation of the retina. They are a frequent symptom in patients irradiated in the region of the central nervous system (CNS), head and neck and the eyes. Phosphenes have historically been attributed to complex physical phenomena such as Cherenkov radiation...
September 8, 2017: Oncotarget
https://www.readbyqxmd.com/read/28966864/accelerating-nonlinear-reconstruction-in-laminar-optical-tomography-by-use-of-recursive-svd-inversion
#7
Mengyu Jia, Jingying Jiang, Wenjuan Ma, Chenxi Li, Shuang Wang, Huijuan Zhao, Feng Gao
Image reconstruction in the most model-based biophotonic imaging modalities essentially poses an ill-posed nonlinear inverse problem, which has been effectively tackled in the diffusion-approximation-satisfied scenarios such as diffuse optical tomography. Nevertheless, a nonlinear implementation in high-resolution laminar optical tomography (LOT) is normally computationally-costly due to its strong dependency on a dense source-detector configuration and a physically-rigorous photon-transport model. To circumvent the adversity, we herein propose a practical nonlinear LOT approach to the absorption reconstruction...
September 1, 2017: Biomedical Optics Express
https://www.readbyqxmd.com/read/28949500/bioplasmonic-alloyed-nanoislands-using-dewetting-of-bilayer-thin-films
#8
Minhee Kang, Myeong-Su Ahn, Youngseop Lee, Ki-Hun Jeong
Unlike monometallic materials, bimetallic plasmonic materials offer extensive benefits such as broadband tuning capability or high environmental stability. Here we report a broad range tuning of plasmon resonance of alloyed nanoislands by using solid state dewetting of gold and silver bilayer thin films. Thermal dewetting after successive thermal evaporation of thin metal double-layer films readily forms AuAg-alloyed nano-islands with a precise composition ratio. The complete miscibility of alloyed nanoislands results in programmable tuning of plasmon resonance wavelength in a broadband visible range...
September 26, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28938734/hyperspectral-microscopy-can-detect-metabolic-heterogeneity-within-bovine-post-compaction-embryos-incubated-under-two-oxygen-concentrations-7-versus-20
#9
Melanie L Sutton-McDowall, Martin Gosnell, Ayad G Anwer, Melissa White, Malcolm Purdey, Andrew D Abell, Ewa M Goldys, Jeremy G Thompson
STUDY QUESTION: Can we separate embryos cultured under either 7% or 20% oxygen atmospheres by measuring their metabolic heterogeneity? SUMMARY ANSWER: Metabolic heterogeneity and changes in metabolic profiles in morula exposed to two different oxygen concentrations were not detectable using traditional fluorophore and two-channel autofluorescence but were detectable using hyperspectral microscopy. WHAT IS KNOWN ALREADY: Increased genetic and morphological blastomere heterogeneity is associated with compromised developmental competence of embryos and currently forms the basis for embryo scoring within the clinic...
October 1, 2017: Human Reproduction
https://www.readbyqxmd.com/read/28912561/luminophore-configuration-and-concentration-dependent-optoelectronic-characteristics-of-a-quantum-dot-embedded-dna-hybrid-thin-film
#10
Velu Arasu, Sreekantha Reddy Dugasani, Mallikarjuna Reddy Kesama, Ho Kyoon Chung, Sung Ha Park
To be useful in optoelectronic devices and sensors, a platform comprising stable fluorescence materials is essential. Here we constructed quantum dots (QDs) embedded DNA thin films which aims for stable fluorescence through the stabilization of QDs in the high aspect ratio salmon DNA (SDNA) matrix. Also for maximum luminescence, different concentration and configurations of core- and core/alloy/shell-type QDs were embedded within SDNA. The QD-SDNA thin films were constructed by drop-casting and investigated their optoelectronic properties...
September 14, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28895906/silicon-nitride-photonic-integration-platforms-for-visible-near-infrared-and-mid-infrared-applications
#11
Pascual Muñoz, Gloria Micó, Luis A Bru, Daniel Pastor, Daniel Pérez, José David Doménech, Juan Fernández, Rocío Baños, Bernardo Gargallo, Rubén Alemany, Ana M Sánchez, Josep M Cirera, Roser Mas, Carlos Domínguez
Silicon nitride photonics is on the rise owing to the broadband nature of the material, allowing applications of biophotonics, tele/datacom, optical signal processing and sensing, from visible, through near to mid-infrared wavelengths. In this paper, a review of the state of the art of silicon nitride strip waveguide platforms is provided, alongside the experimental results on the development of a versatile 300 nm guiding film height silicon nitride platform.
September 12, 2017: Sensors
https://www.readbyqxmd.com/read/28875533/expanding-anti-stokes-shifting-in-triplet-triplet-annihilation-upconversion-for-in%C3%A2-vivo-anticancer-prodrug-activation
#12
Ling Huang, Yang Zhao, He Zhang, Kai Huang, Jinyi Yang, Gang Han
A strategy to expand anti-Stokes shifting from the far-red to deep-blue region in metal-free triplet-triplet annihilation upconversion (TTA-UC) is presented. The method is demonstrated by in vivo titration of the photorelease of an anticancer prodrug. This new TTA system has robust brightness and the longest anti-Stokes shift of any reported TTA system. TTA core-shell-structured prodrug delivery capsules that benefit from these properties were developed; they can operate with low-power density far-red light-emitting diode light...
September 5, 2017: Angewandte Chemie
https://www.readbyqxmd.com/read/28873297/enhancing-upconversion-fluorescence-with-a-natural-bio-microlens
#13
Yuchao Li, Xiaoshuai Liu, Xianguang Yang, Hongxiang Lei, Yao Zhang, Baojun Li
Upconversion fluorescence has triggered extensive efforts in the past decade because of its superior physicochemical features and great potential in biomedical and biophotonic studies. However, practical applications of upconversion fluorescence are often hindered by its relatively low luminescence efficiency (<1%). Here, we employ a living yeast or human cell as a natural bio-microlens to enhance the upconversion fluorescence. The natural bio-microlens, which was stably trapped on a fiber probe, could concentrate the excitation light into a subwavelength region so that the upconversion fluorescence of core-shell NaYF4:Yb(3+)/Tm(3+) nanoparticles was enhanced by 2 orders of magnitude...
September 7, 2017: ACS Nano
https://www.readbyqxmd.com/read/28852136/high-predictive-values-of-rbc-membrane-based-diagnostics-by-biophotonics-in-an-integrated-approach-for-autism-spectrum-disorders
#14
Giorgia Giacometti, Carla Ferreri, Anna Sansone, Chryssostomos Chatgilialoglu, Carla Marzetti, Ellas Spyratou, Alexandros G Georgakilas, Marina Marini, Provvidenza M Abruzzo, Alessandra Bolotta, Alessandro Ghezzo, Renato Minguzzi, Annio Posar, Paola Visconti
Membranes attract attention in medicine, concerning lipidome composition and fatty acid correlation with neurological diseases. Hyperspectral dark field microscopy (HDFM), a biophotonic imaging using reflectance spectra, provides accurate characterization of healthy adult RBC identifying a library of 8 spectral end-members. Here we report hyperspectral RBC imaging in children affected by Autism Spectrum Disorder (ASD) (n = 21) compared to healthy age-matched subjects (n = 20), investigating if statistically significant differences in their HDFM spectra exist, that can comprehensively map a membrane impairment involved in disease...
August 29, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28715169/fabrication-of-biocompatible-functional-and-transparent-hybrid-films-based-on-silk-fibroin-and-epoxy-silane-for-biophotonics
#15
Robson R da Silva, Maurício Cavicchioli, Laís R Lima, Caio G Otoni, Hernane S Barud, Silvia H Santagneli, Agnieszka Tercjak, André C Amaral, Renata A Carvalho, Sidney J L Ribeiro
In this work we explored the fabrication of flexible and transparent hybrids of silk fibroin (SF) and epoxy-modified siloxane for photonic applications. It is well-known that regenerated SF solutions can form free-standing films with high transparency. Although SF has a restricted number of chemically reactive side groups, the main issues of as-cast pristine SF films regard the high solubility into aqueous media, brittleness, and low thermal stability. The design of SF films with enhanced functionality but high transparency triggers new opportunities on a broader range of applications in biophotonics...
August 8, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28708389/nanostructured-phthalocyanine-assemblies-with-protein-driven-switchable-photoactivities-for-biophotonic-imaging-and-therapy
#16
Xingshu Li, C-Yoon Kim, Seunghyun Lee, Dayoung Lee, Hyung-Min Chung, Gyoungmi Kim, Si-Hyun Heo, Chulhong Kim, Ki-Sung Hong, Juyoung Yoon
Switchable phototheranostic nanomaterials are of particular interest for specific biosensing, high-quality imaging, and targeted therapy in the field of precision nanomedicine. Here, we develop a "one-for-all" nanomaterial that self-assembles from flexible and versatile phthalocyanine building blocks. The nanostructured phthalocyanine assemblies (NanoPcTBs) display intrinsically unique photothermal and photoacoustic properties. Fluorescence and reactive oxygen species generation can be triggered depending on a targeted, protein-induced, partial disassembly mechanism, which creates opportunities for low-background fluorescence imaging and activatable photodynamic therapy...
August 9, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/28708170/widely-wavelength-tunable-fast-intensity-modulated-light-source-for-biophotonic-applications
#17
Tzu-Feng Huang, Sheng-Hao Tseng, Hsien-Yi Wang, Ming-Che Chan
High modulation depth, fast (megahertz to gigahertz), intensity-modulated light sources of various wavelengths within the 0.7-1.35 μm bio-penetration window are highly desirable for many biophotonic diagnosis systems. In this Letter, we present a novel scheme of a wavelength tunable, ultra-broadband light source which simply consists of a pump laser, a nonlinear fiber, and demodulation circuits. The working wavelength range of the light source is from 0.7 to 1.35 μm which covers a vast part of the bio-penetration window, and its modulation frequencies extends from tens of megahertz to gigahertz...
July 15, 2017: Optics Letters
https://www.readbyqxmd.com/read/28700348/mechanisms-of-phosphenes-in-irradiated-patients
#18
REVIEW
Thibaud Mathis, Stephane Vignot, Cecila Leal, Jean-Pierre Caujolle, Celia Maschi, Martine Mauget-Faÿsse, Laurent Kodjikian, Stéphanie Baillif, Joel Herault, Juliette Thariat
Anomalous visual perceptions have been reported in various diseases of the retina and visual pathways or can be experienced under specific conditions in healthy individuals. Phosphenes are perceptions of light in the absence of ambient light, occurring independently of the physiological and classical photonic stimulation of the retina. They are a frequent symptom in patients irradiated in the region of the central nervous system (CNS), head and neck and the eyes. Phosphenes have historically been attributed to complex physical phenomena such as Cherenkov radiation...
June 28, 2017: Oncotarget
https://www.readbyqxmd.com/read/28686275/power-dependent-upconversion-quantum-yield-of-nayf4-yb-3-er-3-nano-and-micrometer-sized-particles-measurements-and-simulations
#19
Martin Kaiser, Christian Würth, Marco Kraft, Iko Hyppänen, Tero Soukka, Ute Resch-Genger
Photophysical studies of nonlinear lanthanide-doped photon upconverting nanoparticles (UCNPs) increasingly used in biophotonics and photovoltaics require absolute measurements of the excitation power density (P)-dependent upconversion luminescence (UCL) and luminescence quantum yields (ΦUC) for quantifying the material performance, UCL deactivation pathways, and possible enhancement factors. We present here the P-dependence of the UCL spectra, ΦUC, and slope factors of the different emission bands of representative 25 nm-sized oleate-capped β-NaYF4:17% Yb(3+), 3% Er(3+) UCNPs dispersed in toluene and as powder as well as ΦUC of 3 μm-sized upconversion particles (UCμP), all measured with a newly designed integrating sphere setup, enabling controlled variation of P over four orders of magnitude...
July 20, 2017: Nanoscale
https://www.readbyqxmd.com/read/28676880/innovations-and-developments-in-dermatologic-non-invasive-optical-imaging-and-potential-clinical-applications
#20
Eric Tkaczyk
Most dermatologists are aware of the benefits of dermoscopy, and a few are familiar with laser-scanning confocal microscopy. Beyond confocal, there are fully 11 different categories of optical techniques that have been applied to clinical dermatology. This article first provides a comprehensive tabular overview of all these optical diagnostic technologies and then details 4 of the lesser known innovations that are already available or still in development (laser Doppler and speckle imaging, Raman spectroscopy, multiphoton microscopy, photoacoustic tomography), with some potential applications in clinical dermatology (blood flow monitoring, skin cancer diagnosis, composition measurements in atopic dermatitis, skin rejuvenation measurement, and noninvasive sentinel lymph node assessment in melanoma)...
July 5, 2017: Acta Dermato-venereologica
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