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Photomodulation

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https://www.readbyqxmd.com/read/29945441/tunable-nonthermal-distribution-of-hot-electrons-in-a-semiconductor-injected-from-a-plasmonic-gold-nanostructure
#1
Scott Kevin Cushing, Chih-Jung Chen, Chung Li Dong, Xiang-Tian Kong, Alexander O Govorov, Ru-Shi Liu, Nianqiang Wu
For semiconductors photosensitized with organic dyes or quantum dots, transferred electrons are usually considered thermalized at the conduction band edge. This study suggests that the electrons injected from a plasmonic metal into a thin semiconductor shell can be nonthermal with energy up to the plasmon frequency. In other words, the electrons injected into the semiconductor are still hot carriers. Photomodulated X-ray absorption measurements of the Ti L2,3 edge are compared before and after excitation of the plasmon in Au@TiO2 core-shell nanoparticles...
July 24, 2018: ACS Nano
https://www.readbyqxmd.com/read/29869490/photochromic-dte-substituted-1-3-di-2-pyridyl-benzene-platinum-ii-complexes-photomodulation-of-luminescence-and-second-order-nonlinear-optical-properties
#2
Hong Zhao, Eleonora Garoni, Thierry Roisnel, Alessia Colombo, Claudia Dragonetti, Daniele Marinotto, Stefania Righetto, Dominique Roberto, Denis Jacquemin, Julien Boixel, Véronique Guerchais
We disclose a new family of photochromic cyclometalated platinum(II) complexes (PtDTE1 and PtDTE2), where a dithienylethene (DTE) unit is connected at the para-position of the central phenyl ring of (N^C^N) cyclometalated ligand, through two different linkages. Their syntheses are presented along with the X-ray characterizations of both the open and closed isomers of PtDTE1. The investigation of their photophysical properties is made, including absorption, photochromism, emission, and second-order nonlinear properties...
June 18, 2018: Inorganic Chemistry
https://www.readbyqxmd.com/read/29777942/photomodulation-multiple-sessions-as-a-promising-preventive-therapy-for-medication-related-osteonecrosis-of-the-jaws-after-tooth-extraction-in-rats
#3
Cristian Statkievicz, Luan Felipe Toro, João Martins de Mello-Neto, Daniela Pereira de Sá, Cláudio Aparecido Casatti, João Paulo Mardegan Issa, Luciano Tavares Angelo Cintra, Juliano Milanezi de Almeida, Maria José Hitomi Nagata, Valdir Gouveia Garcia, Leticia Helena Theodoro, Edilson Ervolino
The aim of this study was to evaluate the effects of photobiomodulation (PBM) with multiple sessions of low-level laser on the alveolar repair process of rats with major risk factors for medication-related osteonecrosis of the jaws (MRONJ). Senile rats received 0.45 mL of vehicle (VEH and VEH-PBM) or 0.45 mL of 100 μg/kg zoledronate (ZOL and ZOL-PBM) administrated intraperitoneally every two days during seven weeks. After three weeks of initiation of drug treatment the first lower left molar was extracted...
July 2018: Journal of Photochemistry and Photobiology. B, Biology
https://www.readbyqxmd.com/read/29730613/photomodulation-in-the-treatment-of-chronic-pain-in-patients-with-temporomandibular-disorder-protocol-for-cost-effectiveness-analysis
#4
Ana Paula Taboada Sobral, Camila Leal H de Godoy, Kristianne P Santos Fernandes, Sandra Kalil Bussadori, Raquel Agnelli Mesquita Ferrari, Anna Carolina Ratto Tempestini Horliana, Sonia F Monken, Lara J Motta
INTRODUCTION: Epidemiological data show that the signs and symptoms of temporomandibular disorder (TMD) start becoming apparent from 6 years of age, and during adolescence these signs and symptoms are similar to those of adults. The present study aims to estimate the direct costs for treatment of chronic muscle pain with photobiomodulation therapy, occlusal splint and placebo in patients with TMD; to evaluate the effectiveness of photobiomodulation therapy and occlusal splint for treatment of muscle pain in patients with TMD; to analyse the cost-effectiveness of the two proposed treatments for pain; and to describe and compare the results of the analyses of these treatments...
May 5, 2018: BMJ Open
https://www.readbyqxmd.com/read/29727579/caged-sirnas-with-single-crgd-modification-for-photoregulation-of-exogenous-and-endogenous-gene-expression-in-cells-and-mice
#5
Lijia Yu, Duanwei Liang, Changmai Chen, Xinjing Tang
RNA interference (RNAi) mediated gene silencing holds significant promise in gene therapy. It is very important to manually regulate the activity of small interference RNAs (siRNAs) in the controllable mode. Here, we designed and synthesized a series of caged siRNAs through bioconjugation of cyclo(Arg-Gly-Asp-d-Phe-Lys) (cRGD) peptide to the 5' end of siRNA through a photolabile linker. These cRGD modified caged siRNAs allowed for precise light-regulation of gene expression of two exogenous reporter genes (firefly luciferase and green fluorescent protein, GFP) and an endogenous gene (the mitosis motor protein, Eg5) in the integrin αv β3 positive cells...
July 9, 2018: Biomacromolecules
https://www.readbyqxmd.com/read/29629072/caged-circular-sirnas-for-photomodulation-of-gene-expression-in-cells-and-mice
#6
Liangliang Zhang, Duanwei Liang, Yuan Wang, Dong Li, Jinhao Zhang, Li Wu, Mengke Feng, Fan Yi, Luzheng Xu, Liandi Lei, Quan Du, XinJing Tang
By means of RNA interference (RNAi), small interfering RNAs (siRNAs) play important roles in gene function study and drug development. Recently, photolabile siRNAs were developed to elucidate the process of gene silencing in terms of space, time and degree through chemical modification of siRNAs. We report herein a novel type of photolabile siRNA that was synthesized through cyclizing two ends of a single stranded RNA with a photocleavable linker. These circular siRNAs became more resistant to serum degradation...
January 7, 2018: Chemical Science
https://www.readbyqxmd.com/read/29529555/laser-assisted-atom-probe-tomography-of-semiconductors-the-impact-of-the-focused-ion-beam-specimen-preparation
#7
J Bogdanowicz, A Kumar, C Fleischmann, M Gilbert, J Houard, A Vella, W Vandervorst
This paper demonstrates the increased light absorption efficiency of semiconducting atom probe tips resulting from focused-ion-beam (FIB) preparation. We use transmission electron microscopy to show that semiconducting tips prepared with FIB are surrounded with an amorphized shell. Photomodulated optical reflectance measurements then provide evidence that FIB-induced damage leads to an increase in both sub- and supra-bandgap light absorption efficiency. Using laser-assisted atom probe tomography (La-APT) measurements, we finally show that, for a nanoscale tip geometry, the laser-induced heating of a tip during La-APT is enhanced by the FIB preparation...
May 2018: Ultramicroscopy
https://www.readbyqxmd.com/read/29488297/photomodulating-gene-expression-by-using-caged-sirnas-with-single-aptamer-modification
#8
Liangliang Zhang, Changmai Chen, Xinli Fan, Xinjing Tang
Caged siRNAs incorporating terminal modification were rationally designed for photochemical regulation of gene silencing induced by RNA interference (RNAi). Through the conjugation of a single oligonucleotide aptamer at the 5' terminus of the antisense RNA strand, enhancement of the blocking effect for RNA-induced silencing complex (RISC) formation/processing was expected, due both/either to the aptamers themselves and/or to their interaction with large binding proteins. Two oligonucleotide aptamers (AS1411 and MUC-1) were chosen for aptamer-siRNA conjugation through a photolabile linker...
June 18, 2018: Chembiochem: a European Journal of Chemical Biology
https://www.readbyqxmd.com/read/29470065/synthesis-and-characterization-of-a-bidirectional-photoswitchable-antagonist-toolbox-for-real-time-gpcr-photopharmacology
#9
Niels J Hauwert, Tamara A M Mocking, Daniel Da Costa Pereira, Albert J Kooistra, Lisa M Wijnen, Gerda C M Vreeker, Eléonore W E Verweij, Albertus H De Boer, Martine J Smit, Chris De Graaf, Henry F Vischer, Iwan J P de Esch, Maikel Wijtmans, Rob Leurs
Noninvasive methods to modulate G protein-coupled receptors (GPCRs) with temporal and spatial precision are in great demand. Photopharmacology uses photons to control in situ the biological properties of photoswitchable small-molecule ligands, which bodes well for chemical biological precision approaches. Integrating the light-switchable configurational properties of an azobenzene into the ligand core, we developed a bidirectional antagonist toolbox for an archetypical family A GPCR, the histamine H3 receptor (H3 R)...
March 28, 2018: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/29280315/a-photoinduced-reversible-phase-transition-in-a-dipeptide-supramolecular-assembly
#10
Xianbao Li, Jinbo Fei, Youqian Xu, Dongxiang Li, Tingting Yuan, Guangle Li, Chenlei Wang, Junbai Li
Tunable supramolecular assembly has found various applications in biomedicine, molecular catalysis, optoelectronics, and nanofabrication. Unlike traditional covalent conjugation, non-covalent introduction of a photoswitchable moiety enables reversible photomodulation of non-photosensitive dipeptide supramolecular assembly. Under light illumination, a long-lived photoacid generator releases a proton and mediates the dissociation of dipeptide-based organogel, thereby resulting in sol formation. Under darkness, the photoswitchable moiety entraps a proton, resulting in gel regeneration...
February 12, 2018: Angewandte Chemie
https://www.readbyqxmd.com/read/29200269/viologen-based-photochromic-coordination-polymers-for-inkless-and-erasable-prints
#11
Wei-Qiu Kan, Shi-Zheng Wen, Yuan-Chun He, Chao-Yue Xu
Four coordination polymers, namely, [Zn(HL1)(L2)0.5 ]·H2 O (1), [Cd(HL1)(L2)0.5 ]·H2 O (2), [Zn(L1)(L3)0.5 ]·H2 O (3), and [Cd(L1)(L3)0.5 ] (4) (H3 L1 = (3,5-dicarboxyl-phenyl)-(4-(2'-carboxyl-phenyl)-benzyl)ether, H2 L2Cl2 = 1,1'-bis(4-carboxy-benzyl)-4,4'-bipyridinium dichloride, and L3Cl2 = 1,1'-dimethyl-4,4'-bipyridylium dichloride), have been synthesized hydrothermally. The structures of compounds 1-4 have been determined by single-crystal X-ray diffraction analyses, and further characterized by elemental analyses, infrared (IR) spectra, powder X-ray diffraction (PXRD) analyses, and thermogravimetric analyses...
December 18, 2017: Inorganic Chemistry
https://www.readbyqxmd.com/read/29147023/nitrogen-related-intermediate-band-in-p-rich-gan-x-p-y-as-1-x-y-alloys
#12
K Zelazna, M Gladysiewicz, M P Polak, S Almosni, A Létoublon, C Cornet, O Durand, W Walukiewicz, R Kudrawiec
The electronic band structure of phosphorus-rich GaNx Py As1-x-y alloys (x ~ 0.025 and y ≥ 0.6) is studied experimentally using optical absorption, photomodulated transmission, contactless electroreflectance, and photoluminescence. It is shown that incorporation of a few percent of N atoms has a drastic effect on the electronic structure of the alloys. The change of the electronic band structure is very well described by the band anticrossing (BAC) model in which localized nitrogen states interact with the extended states of the conduction band of GaAsP host...
November 16, 2017: Scientific Reports
https://www.readbyqxmd.com/read/29105169/photomodulation-of-dna-templated-supramolecular-assemblies
#13
Jenifer Rubio-Magnieto, Tuan-Anh Phan, Mathieu Fossépré, Valérie Matot, Jérémie Knoops, Thibaut Jarrosson, Pascal Dumy, Francoise Serein-Spirau, Claude Niebel, Sébastien Ulrich, Mathieu Surin
A new type of DNA ligand that contains a phosphate-binding group and a photoresponsive azobenzene moiety is reported. When the azobenzene is in trans configuration, the ligand binds to the minor groove of a double-stranded DNA, whereas it partially desorbs upon trans-cis isomerization with light. The ability to photoswitch the ligand upon interaction with DNA is evidenced by (chir)optical signatures, and deciphered by the differences of binding geometry, stability, and dynamics of the DNA/ligand complexes for the two isomers...
November 3, 2017: Chemistry: a European Journal
https://www.readbyqxmd.com/read/29065997/light-emitting-diode-585nm-photomodulation-inhibiting-melanin-synthesis-and-inducing-autophagy-in-human-melanocytes
#14
Li Chen, Zhongyi Xu, Min Jiang, Chengfeng Zhang, Xuan Wang, Leihong Xiang
BACKGROUND: Melasma is a common hyperpigmentation skin disease on face. Light-emitting diode (LED) photomodulation (585nm) is reported to be effective for the treatment of melasma. However, whether and how LED photomodulation would influence melanogenesis of human epidermal melanocytes (HEMs) is unknown. OBJECTIVE: To evaluate the effects of LED photomodulation (585nm) on melanogenesis in HEMs. METHODS: HEMs were irradiated with fluences of 0, 5, 10 and 20J/cm2 585nm LED light...
January 2018: Journal of Dermatological Science
https://www.readbyqxmd.com/read/28834225/controlling-plasmon-enhanced-fluorescence-via-intersystem-crossing-in-photoswitchable-molecules
#15
Mingsong Wang, Gregory Hartmann, Zilong Wu, Leonardo Scarabelli, Bharath Bangalore Rajeeva, Jeremy W Jarrett, Evan P Perillo, Andrew K Dunn, Luis M Liz-Marzán, Gyeong S Hwang, Yuebing Zheng
By harnessing photoswitchable intersystem crossing (ISC) in spiropyran (SP) molecules, active control of plasmon-enhanced fluorescence in the hybrid systems of SP molecules and plasmonic nanostructures is achieved. Specifically, SP-derived merocyanine (MC) molecules formed by photochemical ring-opening reaction display efficient ISC due to their zwitterionic character. In contrast, ISC in quinoidal MC molecules formed by thermal ring-opening reaction is negligible. The high ISC rate can improve fluorescence quantum yield of the plasmon-modified spontaneous emission, only when the plasmonic electromagnetic field enhancement is sufficiently high...
October 2017: Small
https://www.readbyqxmd.com/read/28593105/photobiomodulation-with-near-infrared-light-helmet-in-a-pilot-placebo-controlled-clinical-trial-in-dementia-patients-testing-memory-and-cognition
#16
Marvin H Berman, James P Halper, Trent W Nichols, H Jarrett, Alan Lundy, Jason H Huang
Alzheimer's disease (AD) is a common, chronic expensive debilitating neurodegenerative disease with no current treatments to prevent the physical deterioration of the brain and the consequent cognitive deficits. The current pathophysiology of Alzheimer's disease is the accumulation of neurofibrillary tangles (NFTs) of hyperphosphorylated tau protein and amyloid-beta (Aβ) plaques. Antibody therapy of Tau and Amyloid beta, vaccines and other methods to decrease Tau and or Amyloid have not been successful after considerable pharmaceutical and biotech efforts...
2017: Journal of neurology and neuroscience
https://www.readbyqxmd.com/read/28567253/photomodulation-of-bacterial-growth-and-biofilm-formation-using-carbohydrate-based-surfactants
#17
Yingxue Hu, Wenyue Zou, Villy Julita, Rajesh Ramanathan, Rico F Tabor, Reece Nixon-Luke, Gary Bryant, Vipul Bansal, Brendan L Wilkinson
Naturally occurring and synthetic carbohydrate amphiphiles have emerged as a promising class of antimicrobial and antiadhesive agents that act through a number of dynamic and often poorly understood mechanisms. In this paper, we provide the first report on the application of azobenzene trans-cis photoisomerization for effecting spatial and temporal control over bacterial growth and biofilm formation using carbohydrate-based surfactants. Photocontrollable surface tension studies and small angle neutron scattering (SANS) revealed the diverse geometries and dimensions of self-assemblies (micelles) made possible through variation of the head group and UV-visible light irradiation...
November 1, 2016: Chemical Science
https://www.readbyqxmd.com/read/28534738/optocontrol-of-glutamate-receptor-activity-by-single-side-chain-photoisomerization
#18
Viktoria Klippenstein, Christian Hoppmann, Shixin Ye, Lei Wang, Pierre Paoletti
Engineering light-sensitivity into proteins has wide ranging applications in molecular studies and neuroscience. Commonly used tethered photoswitchable ligands, however, require solvent-accessible protein labeling, face structural constrains, and are bulky. Here, we designed a set of optocontrollable NMDA receptors by directly incorporating single photoswitchable amino acids (PSAAs) providing genetic encodability, reversibility, and site tolerance. We identified several positions within the multi-domain receptor endowing robust photomodulation...
May 23, 2017: ELife
https://www.readbyqxmd.com/read/28531349/low-temperature-pm-irras-of-a-monolayer-on-au-spectra-of-c-18-d-37-sh
#19
Milan Mašát, Jin Wen, Zdeněk Sofer, Josef Michl
We describe an experimental setup suitable for the measurement of photomodulated IR reflection/absorption spectra of monolayers on a flat gold substrate at temperatures from room to 14 K. Results obtained for a monolayer of C18 D37 SH on gold are shown and compared with IR spectra of C18 D37 SH in a KBr pellet at these temperatures. Band widths are reduced by only ∼10%. Upon cooling below 100-150 K, the frequencies and intensities of vas (CD3 ) and vas (CD2 ) bands in the C-D stretching region in both types of spectra undergo reversible changes attributed to disappearance of gauche defects by analogy to the behavior of previously studied chains...
June 13, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
https://www.readbyqxmd.com/read/28493679/light-induced-fluorescence-modulation-of-quantum-dot-crystal-violet-conjugates-stochastic-off-on-off-cycles-for-multicolor-patterning-and-super-resolution
#20
Sungwook Jung, Joonhyuck Park, Jiwon Bang, Jae-Yeol Kim, Cheolhee Kim, Yongmoon Jeon, Seung Hwan Lee, Ho Jin, Sukyung Choi, Bomi Kim, Woo Jin Lee, Chan-Gi Pack, Jong-Bong Lee, Nam Ki Lee, Sungjee Kim
Photoswitching or modulation of quantum dots (QDs) can be promising for many fields that include display, memory, and super-resolution imaging. However, such modulations have mostly relied on photomodulations of conjugated molecules in QD vicinity, which typically require high power of high energy photons at UV. We report a visible light-induced facile modulation route for QD-dye conjugates. QD crystal violets conjugates (QD-CVs) were prepared and the crystal violet (CV) molecules on QD quenched the fluorescence efficiently...
June 7, 2017: Journal of the American Chemical Society
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