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Red dot

Hua Wang, Chun Sun, Xingru Chen, Yu Zhang, Vicki L Colvin, Quinton Rice, Jaetae Seo, Shengyu Feng, Shengnian Wang, William W Yu
Carbon dots (CDs) usually emit a strong blue light and excitation wavelength dependent long wavelength lights. This significantly limits their applications because one has to use a series of different excitation light sources to get different colors and the long wavelength emissions are usually very weak. We found that one type of CDs synthesized from p-phenylenediamine could emit various long wavelength lights (green to red) independent of the excitation wavelength when dispersed in different solvents. The photoluminescence quantum yields of the same CDs were 10-35% in different solvents for different color emissions...
January 17, 2017: Nanoscale
Chang-Zheng Wang, Jia-Li Chen, Ying Tang, Yi Zang, Guo-Rong Chen, Tony D James, Jia Li, Changfeng Wu, Xiao-Peng He
A supramolecular, polymer dot based ensemble has been developed for the ratiometric detection of lectins and targeted delivery of glycoprobes. Self-assembly between a blue-emitting polymer dot and a red-emitting glycoprobe, results in an ensemble that shows red emission upon excitation of the polymer dot because of Förster Resonance Energy Transfer. Resulting in ratiometric detection of lectins in buffer solution as well as targeted delivery of the glycoprobe to cells that highly express a sugar receptor. Unlike conventional systems where both the agent and vector are co-delivered intracellularly, our ensemble developed here shows a receptor-controlled dissociation on the cell membrane...
January 17, 2017: ACS Applied Materials & Interfaces
Samer Bayda, Mohamad Hadla, Stefano Palazzolo, Vinit Kumar, Isabella Caligiuri, Emmanuele Ambrosi, Enrico Pontoglio, Marco Agostini, Tiziano Tuccinardi, Alvise Benedetti, Pietro Riello, Vincenzo Canzonieri, Giuseppe Corona, Giuseppe Toffoli, Flavio Rizzolio
Nanomedicine requires intelligent and non-toxic nanomaterials for real clinical applications. Carbon materials possess interesting properties but with some limitations due to toxic effects. Interest in carbon nanoparticles (CNPs) is increasing because they are considered green materials with tunable optical properties, overcoming the problem of toxicity associated with quantum dots or nanocrystals, and can be utilized as smart drug delivery systems. Using black tea as a raw material, we synthesized CNPs with a narrow size distribution, tunable optical properties covering visible to deep red absorption, non-toxicity and easy synthesis for large-scale production...
January 13, 2017: Journal of Controlled Release: Official Journal of the Controlled Release Society
Kuncheng Yang, Shanshan Wang, Yingyi Wang, Hong Miao, Xiaoming Yang
Herein, carbon dots (CD@Papain) from papain have been originally synthesized in aqueous solution along with a quantum yield of 6.2%, and showed cyan fluorescence at 435nm. Meanwhile, papain-templated Au nanoclusters (AuNCs@Papain) were prepared with the same precursor. On the basis of the two types of nanomaterials, CD@Papain and AuNCs@Papain have been designed to assemble as one nanosensor (termed as CD-AuNCs@Papain) through a typical cross-linking reaction. Significantly, it not only emitted the dual-emission fluorescent signals with the same excitation, but also can assay multiple targets through exhibiting cyan, yellow, and red emission respectively...
January 7, 2017: Biosensors & Bioelectronics
Joaquin Barrera, David Ibañez, Aranzazu Heras, Virginia Ruiz, Alvaro Colina
Changes in the optical properties of graphene quantum dots (GQD) during electrochemical reduction and oxidation were investigated by photoluminescence (PL) spectroelectrochemistry, which provided direct in situ evidence of the dependence of GQD luminescence on their redox state. We demonstrated that GQD PL intensity was enhanced upon reduction (quantum yield increased from 0.44 to 0.55) and substantially bleached during oxidation (quantum yield ∼0.12). Moreover, PL emission blue/red-shifted upon GQD reduction/oxidation, rendering information about electronic transitions involved in the redox processes, namely, the π → π* and the n → π* transitions between energy levels of the aromatic sp(2) domains and the functional groups, respectively...
January 11, 2017: Journal of Physical Chemistry Letters
Y Ma, M Laprise-Pelletier, J Lagueux, M Cote, M Fordin, L Beaulieu
PURPOSE: Gold nanoparticle (GNP) is a promising radiosensitizer that selectively boosts tumor dose in radiotherapy. Transmission electron microscopy (TEM) imaging observations recently revealed for the first time that GNP exists in vivo in the form of highly localized vesicles, instead of hypothetical uniform distribution. This work investigates the corresponding difference of energy deposition in proton therapy. METHODS: First, single vesicles of various radii were constructed by packing GNPs (as Φ50 nm gold spheres) in spheres and were simulated, as well as a single GNP...
June 2016: Medical Physics
Jayasmita Jana, Mainak Ganguly, Kuttay R S Chandrakumar, Gowravaram Mohan Rao, Tarasankar Pal
Attention has been directed toward electron-deficient boron doping in carbon dots (CDs) with the expectation of revealing new photophysical aspects in accordance with varying amounts of boron content. It has been emphatically shown that boron uptake in CDs varies with different boron precursors evolving altered emissive CDs. Boron doping in CDs causes definite surface defect due to the generation of electron-deficient states. Modified hydrothermal treatment of a mixture of ascorbic acid (AA) and different boron precursor compounds (borax/boric acid/sodium borate/sodium borohydride) produces different kinds of boron-doped CDs (BCDs)...
January 6, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
Ateet Dutt, Yasuhiro Matsumoto, G Santana-Rodríguez, Estrella Ramos, B Marel Monroy, J Santoyo Salazar
The impact of the surface reconstruction of the density distribution and photoluminescence of silicon quantum dots (QDs) embedded in a silicon oxide matrix (SiOx) has been studied. Annealing treatments carried out on the as-deposited samples provoked the effusion of hydrogen species. Moreover, depending on the surrounding density and coalescence of QDs, they resulted in a change in the average size of the particles depending on the initial local environment. The shift in the luminescence spectra all over the visible region (blue, green and red) shows a strong dependence on the resultant change in the size and/or the passivation environment of QDs...
January 4, 2017: Physical Chemistry Chemical Physics: PCCP
Joong Pill Park, Jae-Joon Lee, Sang-Wook Kim
We first report the GaAs/ZnSe and InxGa1-xAs/ZnSe core/shell structured colloidal quantum dots (CQDs). GaAs based CQD, which are hard to obtain by the chemical synthetic method, can be prepared successfully using the acetylacetonate complex of indium and gallium as cationic precursors. We control the indium contents, and the photoluminescence emission is tuned from orange to deep red. In0.2Ga0.8As/ZnSe core/shell QDs show the best quantum yield of 25.6%. A ZnSe outer shell protects the core and improves quantum yield, and it shows a large red shift owing to the quasi-type-I band structure...
December 28, 2016: Journal of the American Chemical Society
Utkarsh Jain, Anamika Singh, Naresh Kumar Kuchhal, Nidhi Chauhan
Excessive glucose present in the blood of diabetic patients binds with the hemoglobin of red blood cells resulting in the formation of glycated hemoglobin (HbA1c). Measurement of HbA1c levels may help in identifying the efficacy of the ongoing treatment and hence provide a better control over the disease. In the present study, we have synthesized a sensitive and stable scaffold, which consists of Au nanoparticles (GNPs)-dotted tubular TiO2, for the construction of an electrochemical HbA1c biosensor. 12-phosphotungstic acid has been used as a reducer after depositing well-dispersed GNPs on TiO2 nanotubes (TiO2 NTs) and an electron mediator by accelerating the electron transfer between the conductor and protein...
November 16, 2016: Analytica Chimica Acta
Astrid Foubert, Natalia V Beloglazova, Anna Gordienko, Mickael D Tessier, Emile Drijvers, Zeger Hens, Sarah De Saeger
A multiplex lateral flow immunoassay (LFIA) for the determination of the mycotoxins deoxynivalenol, zearalenone, and T2/HT2-toxin in barley was developed with luminescent quantum dots (QDs) as label. The synthesized QDs were hydrophilized by two strategies, that is, coating with an amphiphilic polymer or silica. The water-soluble QDs were compared with regard to their bioconjugation with monoclonal antibody (mAb) and were tested on a LFIA. Silica-coated QDs that contained epoxy groups were most promising. Therefore, green, orange, and red epoxy-functionalized silica-coated QDs were conjugated with anti-ZEN, anti-DON, and anti-T2 mAb, respectively...
December 12, 2016: Journal of Agricultural and Food Chemistry
Hao Jiang, Sheida Alan, Haleh Shahbazbegian, Jasbir N Patel, Bozena Kaminska
Inkjet printing of silver ink has been widely used to print conductive patterns in flexible electronic devices, and the printed patterns are commonly known to be colorless. We demonstrate that by printing a single type of ordinary silver nanoparticle ink on top of a substrate patterned with polymer nanostructures, the printed silver is molded by the nanostructures and gains robust structural colors. The colors are tunable by varying the geometries of nanostructures, and a broad range of visual colors can be achieved by mixing the red, green, and blue colors displayed from silver dots printed on different nanostructures...
November 22, 2016: ACS Nano
Hujia Cao, Junliang Ma, Lin Huang, Haiyan Qin, Renyang Meng, Yang Li, Xiaogang Peng
Single-molecular spectroscopy reveals that photoluminescence (PL) of a single quantum dot blinks, randomly switching between bright and dim/dark states under constant photoexcitation, and quantum dots photobleach readily. These facts cast great doubts on potential applications of these promising emitters. After ∼20 years of efforts, synthesis of nonblinking quantum dots is still challenging, with nonblinking quantum dots only available in red-emitting window. Here we report synthesis of nonblinking quantum dots covering most part of the visible window using a new synthetic strategy, i...
December 7, 2016: Journal of the American Chemical Society
Nilanjan Dey, Deepa Bhagat, Durgadas Cherukaraveedu, Santanu Bhattacharya
Red-light-emitting water-soluble semiconducting quantum dots (QDs) were synthesized by using a wide variety of commercially available thiol-type capping agents. QDs with a negatively charged nanosurface showed excellent selectivity for paraquat (PQ) at pH 7.4 over other commonly encountered pesticides/herbicides, including diquat (DQ). The presence of a 4,4'-bis-pyridinium unit in PQ enabled it to initiate long-range aggregation, thereby leading to the formation of nanostructures with excellent emission-quenching behavior...
January 3, 2017: Chemistry, An Asian Journal
Damien Wright, Alexis D J Makin, Marco Bertamini
Symmetry is a highly salient feature in the visual world, abundant in both man-made and natural objects. In particular, humans find reflectional symmetry most salient. Electrophysiological work on symmetry perception has identified a difference wave known as the Sustained Posterior Negativity (SPN) originating from extrastriate areas. Amplitude is more negative for symmetrical than random patterns, from around 200 msec after stimulus onset. For the first time, we report responses to patterns presented exclusively in one hemifield...
November 10, 2016: Cortex; a Journal Devoted to the Study of the Nervous System and Behavior
Kee Suck Suh, Jong Bin Park, Myeong Hyeon Yang, Soo Young Choi, Hyun Hwangbo, Min Soo Jang
Lichen aureus (LA) is a variant of pigmented purpuric dermatosis that is characterized clinically by rust macules, papules or plaques, mainly on the legs. In some cases, LA can be difficult to be distinguished from nummular eczema (NE) with the naked eye. Dermoscopy can be applied to skin lesions, revealing additional features that can be highly valuable for correct diagnosis. This study was conducted to investigate characteristic dermoscopic findings of LA and to identify distinctive features that can differentiate it from NE...
December 3, 2016: Journal of Dermatology
N Zhang, Y Yang, H Lu, Y Xiang, X Huang, R Hu, Z Chen, W Yuan, R Peng, J Peng, H Ai, K Liu
It is known that the autophagy-related protein 1 (ATG1) plays critical roles in the regulation of autophagy in mammals and yeast, whereas the function of ATG1 in lepidopteran insects is not well elucidated. Here Spodoptera litura ATG1 (SlATG1) and its interactions with other ATG proteins were characterized. Alternative splicing of SlAtg1 produced at least four transcript variants. Over-expression and RNA interference knockdown of SlAtg1 demonstrated that SlATG1 enhanced autophagy. SlATG1A-Green fluorescent protein (GFP) tagged localized in the cytoplasm and formed some punctuate dots, which were colocalized with red fluorescent protein mCherry tagged Spodoptera exigua ATG5 (SeATG5)...
November 30, 2016: Insect Molecular Biology
Norman Forschack, Søren K Andersen, Matthias M Müller
A key property of feature-based attention is global facilitation of the attended feature throughout the visual field. Previously, we presented superimposed red and blue randomly moving dot kinematograms (RDKs) flickering at a different frequency each to elicit frequency-specific steady-state visual evoked potentials (SSVEPs) that allowed us to analyze neural dynamics in early visual cortex when participants shifted attention to one of the two colors. Results showed amplification of the attended and suppression of the unattended color as measured by SSVEP amplitudes...
November 29, 2016: Journal of Cognitive Neuroscience
Gaofeng Liang, Yang Li, Wenpo Feng, Xinshuai Wang, Aihua Jing, Jinghua Li, Kaiwang Ma
Quantum dots (QDs) have been intensively investigated for bioimaging, drug delivery, and labeling probes because of their unique optical properties. In this study, CdSe/ZnS QDs-based nonviral vectors with the dual functions of delivering miR-26a plasmid and bioimaging were formulated by capping the surface of CdSe/ZnS QDs with polyethyleneimine (PEI). The PEI-coated QDs were capable of condensing miR-26a expression vector into nanocomplexes that can emit strong red luminescence when loaded with CdSe/ZnS QDs...
2016: International Journal of Nanomedicine
Tyler J Goodwin, Leaf Huang
No abstract text is available yet for this article.
December 10, 2016: Journal of Controlled Release: Official Journal of the Controlled Release Society
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