Dots

Distribution by Scientific Domains

Kinds of Dots

  • InA quantum dot
  • InGaA quantum dot
  • cd quantum dot
  • cdse quantum dot
  • cdse/zns quantum dot
  • cdse/znse quantum dot
  • cdte quantum dot
  • colloidal quantum dot
  • double quantum dot
  • fluorescent quantum dot
  • gan quantum dot
  • gan/aln quantum dot
  • inas/gaas quantum dot
  • ingan quantum dot
  • inn quantum dot
  • quantum dot
  • self-assembled inas/gaas quantum dot
  • semiconductor quantum dot
  • silicon quantum dot
  • single inas/gaas quantum dot
  • single quantum dot
  • spherical quantum dot
  • yellow dot

  • Terms modified by Dots

  • dot array
  • dot blot
  • dot blot analysis
  • dot blot hybridization
  • dot embedded
  • dot laser
  • dot layer
  • dot molecule
  • dot pattern
  • dot structure
  • dot superlattice
  • dot system

  • Selected Abstracts


    Fractional CO2 laser: a novel therapeutic device upon photobiomodulation of tissue remodeling and cytokine pathway of tissue repair

    DERMATOLOGIC THERAPY, Issue 2009
    F. Prignano
    ABSTRACT Minimally ablative fractional laser devices have gained acceptance as a preferred method for skin resurfacing. Notable improvements in facial rhytides, photodamage, acne scarring, and skin laxity have been reported. The aim of the present work was to compare how different CO2 laser fluences, by modulating the secretory pathway of cytokines, are able to influence the wound-healing process, and how these fluences are associated with different clinical results. Eighteen patients, all with photodamaged skin, were treated using a fractional CO2 laser (SmartXide DOT, Deka M.E.L.A., Florence, Italy) with varying laser fluences (2.07, 2.77, and 4.15 J/cm2). An immunocytochemical study was performed at defined end points in order to obtain information about specific cytokines of the microenvironment before and after treatment. The secretory pathway of cytokines changed depending on the re-epithelization and the different laser fluences. Different but significant improvements in wrinkles, skin texture, and hyperpigmentation were definitely obtained when using 2.07, 2.77, and 4.15 J/cm2, indicating fractional CO2 laser as a valuable tool in photorejuvenation with good clinical results, rapid downtime, and an excellent safety profile. [source]


    An EM-like reconstruction method for diffuse optical tomography

    INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING, Issue 9 2010
    *Article first published online: 28 JUN 2010, Caifang Wang
    Abstract Diffuse optical tomography (DOT) is an optical imaging modality which provides the spatial distributions of optical parameters inside an object. The forward model of DOT is described by the diffusion approximation of radiative transfer equation, while the DOT is to reconstruct the optical parameters from boundary measurements. In this paper, an EM-like iterative reconstruction method specifically for the steady state DOT problem is developed. Previous iterative reconstruction methods are mostly based on the assumption that the measurement noise is Gaussian, and are of least-squares type. In this paper, with the assumption that the boundary measurements have independent and identical Poisson distributions, the inverse problem of DOT is solved by maximizing a log-likelihood functional with inequality constraints, and then an EM-like reconstruction algorithm is developed according to the Kuhn,Tucker condition. The proposed algorithm is a variant of the well-known EM algorithm. The performance of the proposed algorithm is tested with three-dimensional numerical simulation. Copyright 2010 John Wiley & Sons, Ltd. [source]


    Parallel Algorithms for Dynamic Shortest Path Problems

    INTERNATIONAL TRANSACTIONS IN OPERATIONAL RESEARCH, Issue 3 2002
    Ismail Chabini
    The development of intelligent transportation systems (ITS) and the resulting need for the solution of a variety of dynamic traffic network models and management problems require faster-than-real-time computation of shortest path problems in dynamic networks. Recently, a sequential algorithm was developed to compute shortest paths in discrete time dynamic networks from all nodes and all departure times to one destination node. The algorithm is known as algorithm DOT and has an optimal worst-case running-time complexity. This implies that no algorithm with a better worst-case computational complexity can be discovered. Consequently, in order to derive algorithms to solve all-to-one shortest path problems in dynamic networks, one would need to explore avenues other than the design of sequential solution algorithms only. The use of commercially-available high-performance computing platforms to develop parallel implementations of sequential algorithms is an example of such avenue. This paper reports on the design, implementation, and computational testing of parallel dynamic shortest path algorithms. We develop two shared-memory and two message-passing dynamic shortest path algorithm implementations, which are derived from algorithm DOT using the following parallelization strategies: decomposition by destination and decomposition by transportation network topology. The algorithms are coded using two types of parallel computing environments: a message-passing environment based on the parallel virtual machine (PVM) library and a multi-threading environment based on the SUN Microsystems Multi-Threads (MT) library. We also develop a time-based parallel version of algorithm DOT for the case of minimum time paths in FIFO networks, and a theoretical parallelization of algorithm DOT on an ,ideal' theoretical parallel machine. Performances of the implementations are analyzed and evaluated using large transportation networks, and two types of parallel computing platforms: a distributed network of Unix workstations and a SUN shared-memory machine containing eight processors. Satisfactory speed-ups in the running time of sequential algorithms are achieved, in particular for shared-memory machines. Numerical results indicate that shared-memory computers constitute the most appropriate type of parallel computing platforms for the computation of dynamic shortest paths for real-time ITS applications. [source]


    Ground truth hardware phantoms for validation of diffusion-weighted MRI applications

    JOURNAL OF MAGNETIC RESONANCE IMAGING, Issue 2 2010
    Pim Pullens MSc
    Abstract Purpose: To quantitatively validate diffusion-weighted MRI (DW-MRI) applications, a hardware phantom containing crossing fibers at a sub-voxel level is presented. It is suitable for validation of a large spectrum of DW-MRI applications from acquisition to fiber tracking, which is an important recurrent issue in the field. Materials and Methods: Phantom properties were optimized to resemble properties of human white matter in terms of anisotropy, fractional anisotropy, and T2. Sub-voxel crossings were constructed at angles of 30, 50, and 65 degrees, by wrapping polyester fibers, with a diameter close to axon diameter, into heat shrink tubes. We show our phantoms are suitable for the acquisition of DW-MRI data using a clinical protocol. Results: The phantoms can be used to succesfully estimate both the diffusion tensor and non-Gaussian diffusion models, and perform streamline fiber tracking. DOT (Diffusion Orientation Transform) and q-ball reconstruction of the diffusion profiles acquired at b = 3000 s/mm2 and 132 diffusion directions reveal multimodal diffusion profiles in voxels containing crossing yarn strands. Conclusion: The highly purpose adaptable phantoms provide a DW-MRI validation platform: applications include optimisation of acquisition schemes, validation of non-Gaussian diffusion models, comparison and validation of fiber tracking algorithms, and quality control in multi-center DWI studies. J. Magn. Reson. Imaging 2010;32:482,488. 2010 Wiley-Liss, Inc. [source]


    Dynamic analysis of GS-NS0 cells producing a recombinant monoclonal antibody during fed-batch culture

    BIOTECHNOLOGY & BIOENGINEERING, Issue 2 2007
    Scott H. Stansfield
    Abstract In this study we have analyzed the dynamic covariation of the mammalian cell proteome with respect to functional phenotype during fed-batch culture of NS0 murine myeloma cells producing a recombinant IgG4 monoclonal antibody. GS-NS0 cells were cultured in duplicate 10 L bioreactors (36.5C, 15% DOT, pH 7.0) for 335 h and supplemented with a continuous feed stream after 120 h. Cell-specific growth rate declined continuously after 72 h of culture. Cell-specific recombinant monoclonal antibody production rate (qP) varied sixfold through culture. Whilst qP correlated with relative recombinant heavy chain mRNA abundance up to 216 h, qP subsequently declined, independent of recombinant heavy chain or light chain mRNA abundance. GS-NS0 cultures were sampled at 48 h intervals between 24 and 264 h of culture for proteomic analyses. Total protein abundance and nascent polypeptide synthesis was determined by 2D PAGE of unlabeled proteins visualized by SYPRO Ruby and autoradiography of 35S-labeled polypeptides, respectively. Covariation of nascent polypeptide synthesis and abundance with biomass-specific cell growth, glucose and glutamate consumption, lactate and Mab production rates were then examined using two partial least squares regression models. Most changes in polypeptide synthesis or abundance for proteins previously identified by mass spectrometry were positively correlated with biomass-specific growth rate. We conclude that the substantial transitions in cell physiology and qP that occur during culture utilize a relatively constant complement of the most abundant host cell machines that vary primarily with respect to induced changes in cell growth rate. Biotechnol. Bioeng. 2007;97: 410,424. 2006 Wiley Periodicals, Inc. [source]


    Integrated Management of Physician-delivered Alcohol Care for Tuberculosis Patients: Design and Implementation

    ALCOHOLISM, Issue 2 2010
    Shelly F. Greenfield
    Background:, While the integration of alcohol screening, treatment, and referral in primary care and other medical settings in the U.S. and worldwide has been recognized as a key health care priority, it is not routinely done. In spite of the high co-occurrence and excess mortality associated with alcohol use disorders (AUDs) among individuals with tuberculosis (TB), there are no studies evaluating effectiveness of integrating alcohol care into routine treatment for this disorder. Methods:, We designed and implemented a randomized controlled trial (RCT) to determine the effectiveness of integrating pharmacotherapy and behavioral treatments for AUDs into routine medical care for TB in the Tomsk Oblast Tuberculosis Service (TOTBS) in Tomsk, Russia. Eligible patients are diagnosed with alcohol abuse or dependence, are newly diagnosed with TB, and initiating treatment in the TOTBS with Directly Observed Therapy-Short Course (DOTS) for TB. Utilizing a factorial design, the Integrated Management of Physician-delivered Alcohol Care for Tuberculosis Patients (IMPACT) study randomizes eligible patients who sign informed consent into 1 of 4 study arms: (1) Oral Naltrexone + Brief Behavioral Compliance Enhancement Therapy (BBCET) + treatment as usual (TAU), (2) Brief Counseling Intervention (BCI) + TAU, (3) Naltrexone + BBCET + BCI + TAU, or (4) TAU alone. Results:, Utilizing an iterative, collaborative approach, a multi-disciplinary U.S. and Russian team has implemented a model of alcohol management that is culturally appropriate to the patient and TB physician community in Russia. Implementation to date has achieved the integration of routine alcohol screening into TB care in Tomsk; an ethnographic assessment of knowledge, attitudes, and practices of AUD management among TB physicians in Tomsk; translation and cultural adaptation of the BCI to Russia and the TB setting; and training and certification of TB physicians to deliver oral naltrexone and brief counseling interventions for alcohol abuse and dependence as part of routine TB care. The study is successfully enrolling eligible subjects in the RCT to evaluate the relationship of integrating effective pharmacotherapy and brief behavioral intervention on TB and alcohol outcomes, as well as reduction in HIV risk behaviors. Conclusions:, The IMPACT study utilizes an innovative approach to adapt 2 effective therapies for treatment of alcohol use disorders to the TB clinical services setting in the Tomsk Oblast, Siberia, Russia, and to train TB physicians to deliver state of the art alcohol pharmacotherapy and behavioral treatments as an integrated part of routine TB care. The proposed treatment strategy could be applied elsewhere in Russia and in other settings where TB control is jeopardized by AUDs. If demonstrated to be effective, this model of integrating alcohol interventions into routine TB care has the potential for expanded applicability to other chronic co-occurring infectious and other medical conditions seen in medical care settings. [source]


    CONNECTING THE DOTS: TOWARDS ARCHAEOLOGICAL NETWORK ANALYSIS

    OXFORD JOURNAL OF ARCHAEOLOGY, Issue 3 2010
    TOM BRUGHMANS
    Summary In recent years network analysis has been applied in archaeological research to examine the structure of archaeological relationships of whatever sort. However, these archaeological applications share a number of issues concerning 1) the role of archaeological data in networks; 2) the diversity of network structures, their consequences and their interpretation; 3) the critical use of quantitative tools; and 4) the influence of other disciplines, especially sociology. This article concerns a deconstruction of past archaeological methods for examining networks. Through a case study of Roman table wares in the eastern Mediterranean, the article highlights a number of issues with network analysis as a method for archaeology. It urges caution regarding the uncritical application of network analysis methods developed in other disciplines and applied to archaeology. However, it stresses the potential benefits of network analysis for the archaeological discipline and acknowledges the need for specifically archaeological network analysis, which should be based on relational thinking and can be expanded with an archaeological toolset for quantitative analysis. [source]


    Horizontal Roadway Curvature Computation Algorithm Using Vision Technology

    COMPUTER-AIDED CIVIL AND INFRASTRUCTURE ENGINEERING, Issue 2 2010
    Yichang (James) Tsai
    However, collecting such data is time-consuming, costly, and dangerous using traditional, manual surveying methods. It is especially difficult to perform such manual measurement when roadways have high traffic volumes. Thus, it would be valuable for transportation agencies if roadway curvature data could be computed from photographic images taken using low-cost digital cameras. This is the first article that develops an algorithm using emerging vision technology to acquire horizontal roadway curvature data from roadway images to perform roadway safety assessment. The proposed algorithm consists of four steps: (1) curve edges image processing, (2) mapping edge positions from an image domain to the real-world domain, (3) calibrating camera parameters, and (4) calculating the curve radius and center from curve points. The proposed algorithm was tested on roadways having various levels of curves and using different image sources to demonstrate its capability. The ground truth curvatures for two cases were also collected to evaluate the error of the proposed algorithm. The test results are very promising, and the computed curvatures are especially accurate for curves of small radii (less than 66 m/200 ft) with less than 1.0% relative errors with respect to the ground truth data. The proposed algorithm can be used as an alternative method that complements the traditional measurement methods used by state DOTs to collect roadway curvature data. [source]


    Quantum Dot,Polymer Composites for Displays: Inkjet-Printed Quantum Dot,Polymer Composites for Full-Color AC-Driven Displays (Adv. Mater.

    ADVANCED MATERIALS, Issue 21 2009
    21/2009)
    Vladimir Bulovic and co-workers show on p. 2151 that colloidal quantum dot-polymer composites are used for inkjet print-deposition of high resolution, patterned, multicolored thin films in the fabrication of robust, bright, full-color AC-driven displays. The inside cover shows an inkjet nozzle with a quantum dot solution and a completed device on a flexible substrate under UV illumination, with inset examples of the achievable high resolution and patterning. [source]


    Inkjet-Printed Quantum Dot,Polymer Composites for Full-Color AC-Driven Displays

    ADVANCED MATERIALS, Issue 21 2009
    Vanessa Wood
    Colloidal quantum dot,polymer composites are used for inkjet-print deposition of high-resolution, patterned, multicolored thin films in the fabrication of robust, bright, full-color AC-driven displays. The left panel shows a photograph of a complete device on a flexible substrate under UV illumination, while the right panel shows photographs of the electroluminescence of red, green, and blue 80 mm2 pixels. [source]


    Photoluminescence Quenching Control in Quantum Dot,Carbon Nanotube Composite Colloids Using a Silica-Shell Spacer,

    ADVANCED MATERIALS, Issue 4 2006
    M. Grzelczak
    One-dimensional nanocomposite colloids are prepared by means of electrostatic self-assembly of CdTe nanocrystals on both carbon nanotubes (CNTs) and silica-coated CNTs (see Figure). The dense coverage of these linear nanoparticle assemblies minimizes the spacing between the nanocrystals, thereby facilitating efficient electronic and energy transfer along the nanotubes. [source]


    Quantum Dot-based Energy Transfer: Perspectives and Potential for Applications in Photodynamic Therapy

    PHOTOCHEMISTRY & PHOTOBIOLOGY, Issue 3 2006
    Anna C. S. Samia
    ABSTRACT Quantum dots have emerged as an important class of material that offers great promise to a diverse range of applications ranging from energy conversion to biomedicine. Here, we review the potential of using quantum dots and quantum dot conjugates as sensitizers for photodynamic therapy (PDT). The photophysics of singlet oxygen generation in relation to quantum dot-based energy transfer is discussed and the possibility of using quantum dots as photosensitizer in PDT is assessed, including their current limitations to applications in biological systems. The biggest advantage of quantum dots over molecular photosensitizers that comes into perspective is their tunable optical properties and surface chemistries. Recent developments in the preparation and photophysical characterization of quantum dot energy transfer processes are also presented in this review, to provide insights on the future direction of quantum dot-based photosensitization studies from the viewpoint of our ongoing research. [source]


    Binding energy of a hydrogenic donor impurity in an ellipsoidal finite-potential quantum dot

    PHYSICA STATUS SOLIDI (B) BASIC SOLID STATE PHYSICS, Issue 7 2007
    M. Barati
    Abstract In this article, the binding energy of a hydrogenic donor impurity in weakly oblate Ellipsoidal Quantum Dot (EQD), using the perturbation theory within the framework of effective mass approximation, is investigated. In this regard, the binding energies of 1S, 2S and 2P0 states for GaAs/AlxGa1,xAs structures, as functions of the dot radius and ellipticity constant, are calculated. Results show that variations of binding energies of a hydrogenic impurity with respect to the dot dimension are similar to the case of Spherical Quantum Dot (SQD). In addition, it is found that the binding energy is inversely proportional to the ellipticity constant. This behavior is more profound for 2P0 state, where, depending on the dot's dimensionality and ellipticity, the binding energy may become negative. ( 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]


    Living Yeast Cells as a Controllable Biosynthesizer for Fluorescent Quantum Dots

    ADVANCED FUNCTIONAL MATERIALS, Issue 15 2009
    Ran Cui
    Abstract There are currently some problems in the field of chemical synthesis, such as environmental impact, energy loss, and safety, that need to be tackled urgently. An interdisciplinary approach, based on different backgrounds, may succeed in solving these problems. Organisms can be chosen as potential platforms for materials fabrication, since biosystems are natural and highly efficient. Here, an example of how to solve some of these chemical problems through biology, namely, through a novel biological strategy of coupling intracellular irrelated biochemical reactions for controllable synthesis of multicolor CdSe quantum dots (QDs) using living yeast cells as a biosynthesizer, is demonstrated. The unique fluorescence properties of CdSe QDs can be utilized to directly and visually judge the biosynthesis phase to fully demonstrate this strategy. By such a method, CdSe QDs, emitting at a variety of single fluorescence wavelengths, can be intracellularly, controllably synthesized at just 30C instead of at 300C with combustible, explosive, and toxic organic reagents. This green biosynthetic route is a novel strategy of coupling, with biochemical reactions taking place irrelatedly, both in time and space. It involves a remarkable decrease in reaction temperature, from around 300 C to 30 C and excellent color controllability of CdSe photoluminescence. It is well known that to control the size of nanocrystals is a mojor challenge in the biosynthesis of high-quality nanomaterials. The present work demonstrates clearly that biological systems can be creatively utilized to realize controllable unnatural biosynthesis that normally does not exist, offering new insights for sustainable chemistry. [source]


    Plasma Nanoparticle Synthesis: Luminescent Colloidal Dispersion of Silicon Quantum Dots from Microwave Plasma Synthesis: Exploring the Photoluminescence Behavior Across the Visible Spectrum (Adv. Funct.

    ADVANCED FUNCTIONAL MATERIALS, Issue 5 2009
    Mater.
    The cover picture shows a view into the plasma zone of a microwave plasma reactor, which is used to synthesize macroscopic quantities of single crystalline silicon nanoparticles with a very high production rate. These nanoparticles exhibit bright luminescence across the visible spectrum. On page 696, the authors report that the emission of such silicon nanoparticles can be tuned by changing their size and surface chemistry. [source]


    Luminescent Colloidal Dispersion of Silicon Quantum Dots from Microwave Plasma Synthesis: Exploring the Photoluminescence Behavior Across the Visible Spectrum

    ADVANCED FUNCTIONAL MATERIALS, Issue 5 2009
    Anoop Gupta
    Abstract Aiming for a more practical route to highly stable visible photoluminescence (PL) from silicon, a novel approach to produce luminescent silicon nanoparticles (Si-NPs) is developed. Single crystalline Si-NPs are synthesized by pyrolysis of silane (SiH4) in a microwave plasma reactor at very high production rates (0.1,10,g,h,1). The emission wavelength of the Si-NPs is controlled by etching them in a mixture of hydrofluoric acid and nitric acid. Emission across the entire visible spectrum is obtained by varying the etching time. It is observed that the air oxidation of the etched Si-NPs profoundly affects their optical properties, and causes their emission to blue-shift and diminish in intensity with time. Modification of the silicon surface by UV-induced hydrosilylation also causes a shift in the spectrum. The nature of the shift (red/blue) is dependent on the emission wavelength of the etched Si-NPs. In addition, the amount of shift depends on the type of organic ligand on the silicon surface and the UV exposure time. The surface modification of Si-NPs with different alkenes results in highly stable PL and allows their dispersion in a variety of organic solvents. This method of producing macroscopic quantities of Si-NPs with very high PL stability opens new avenues to applications of silicon quantum dots in optoelectronic and biological fields, and paves the way towards their commercialization. [source]


    Photosensitization of TiO2 Nanostructures with CdS Quantum Dots: Particulate versus Tubular Support Architectures

    ADVANCED FUNCTIONAL MATERIALS, Issue 5 2009
    David R. Baker
    Abstract TiO2 nanotube arrays and particulate films are modified with CdS quantum dots with an aim to tune the response of the photoelectrochemical cell in the visible region. The method of successive ionic layer adsorption and reaction facilitates size control of CdS quantum dots. These CdS nanocrystals, upon excitation with visible light, inject electrons into the TiO2 nanotubes and particles and thus enable their use as photosensitive electrodes. Maximum incident photon to charge carrier efficiency (IPCE) values of 55% and 26% are observed for CdS sensitized TiO2 nanotube and nanoparticulate architectures respectively. The nearly doubling of IPCE observed with the TiO2 nanotube architecture is attributed to the increased efficiency of charge separation and transport of electrons. [source]


    Hydrothermal Route for Cutting Graphene Sheets into Blue-Luminescent Graphene Quantum Dots

    ADVANCED MATERIALS, Issue 6 2010
    Dengyu Pan
    Water-soluble graphene quantum dots (GQDs, ca. 10 nm in diameter) that exhibit bright blue photoluminescence (PL) are prepared by hydrothermal (chemical) cutting of oxidized graphene sheets (see figure). The mechanisms of the cutting and luminescence are discussed. This discovery of PL of GQDs may extend the range of application of graphene-based materials to optoelectronics and biological labeling. [source]


    Electroluminescent Cu-doped CdS Quantum Dots

    ADVANCED MATERIALS, Issue 28 2009
    Jan W. Stouwdam
    Incorporating Cu-doped CdS quantum dots into a polymer host produces efficient light-emitting diodes. The Cu dopant creates a trap level that aligns with the valence band of the host, enabling the direct injection of holes into the quantum dots, which act as emitters. At low current densities, the luminance efficiency maximizes at 9,cd A,1, providing an external quantum efficiency of 5%. [source]


    Quantum Dots: Self-Assembled Quantum Dot Molecules (Adv. Mater.

    ADVANCED MATERIALS, Issue 25-26 2009
    26/2009)
    The cover shows a 2D photoluminescence intensity map from a self-assembled lateral quantum dot molecule in an electric field applied along the molecular axis. The coupling of the two quantum dots is evidenced by intricate spectral line anticrossings, indicated by dotted lines, as reported in the review by Lijuan Wang and co-workers on p. 2601. A 3D AFM image of a lateral quantum dot molecule overlapped with the ground-state electron wavefunction is shown in the inset. [source]


    Highly Efficient Green-Light-Emitting Diodes Based on CdSe@ZnS Quantum Dots with a Chemical-Composition Gradient

    ADVANCED MATERIALS, Issue 17 2009
    Wan Ki Bae
    Highly efficient green-light-emitting diodes (LEDs) based on CdSe@ZnS quantum dots (QDs) with a chemical-composition gradient are demonstrated. Through the moderate control of QD coverage in multilayered devices, excellent device performance has been achieved. The color-saturated green-light emission (see figure for Commission Internationale de l'Eclairage (CIE) co-ordinates) is mainly from the QD layers (more than 99% of total emission). [source]


    Template-Guided Self-Assembly of Colloidal Quantum Dots Using Plasma Lithography

    ADVANCED MATERIALS, Issue 12 2009
    Michael Junkin
    A plasma lithography technique is developed to guide the self-assembly of colloidal quantum dots and other nanoscale building blocks, including fluorescent nanoparticles, gold nanoparticles, salts, and proteins. Plasma lithography enables the self-assembly of nanoscale materials onto soft and polymeric substrates with feature sizes as small as 100,nm. [source]


    Water-Soluble Silicon Quantum Dots with Wavelength-Tunable Photoluminescence

    ADVANCED MATERIALS, Issue 6 2009
    Zhenhui Kang
    H-terminated Si quantum dots (Si QDs) with 3,nm diameter are converted to water-soluble uniform-sized Si QDs after controlled oxidation in an EtOH/H2O2 solution. These dots present Si/SiOxHy core/shell nanostructures, and can be finely tuned to emit light in seven different colors due to the quantum size effect in the Si cores, exhibiting excellent photocatalytic activity in the visible range. [source]


    Aqueous Near-Infrared Fluorescent Composites Based on Apoferritin-Encapsulated PbS Quantum Dots,

    ADVANCED MATERIALS, Issue 19 2008
    Barbara Hennequin
    PbS nanocrystals entrapped in the hollow core of apoferritin protein cages are synthesized in aqueous solution by both reassembly and nanoreactor routes. In both cases, apoferritin limits the size of the PbS quantum dot it can encapsulate to 8 nm and provides a route to the creation of a stable near-infrared fluorescent composite. [source]


    Hybrid Light-Emitting Diodes from Microcontact-Printing Double-Transfer of Colloidal Semiconductor CdSe/ZnS Quantum Dots onto Organic Layers,

    ADVANCED MATERIALS, Issue 10 2008
    Aurora Rizzo
    A novel dry deposition approach is developed to transfer arrays of colloidal quantum dots onto organic thin films, as illustrated in the figure. A red light-emitting device combining inorganic and organic components is fabricated based on this simple transfer protocol. [source]


    Fabrication of Highly Ordered Silicon Oxide Dots and Stripes from Block Copolymer Thin Films,

    ADVANCED MATERIALS, Issue 4 2008
    S. Park
    A general route to fabricate highly ordered arrays of nanoscopic silicon oxide dots and stripes (see figure) from block copolymer thin films is described. Poly(styrene- b -4-vinylpyridine) thin films with cylindrical microdomains oriented normal and parallel to the surface were used as templates for the fabrication of nanoscopic silicon oxide, with polydimethylsiloxane as the inorganic precursor. [source]


    GdIII -Functionalized Fluorescent Quantum Dots as Multimodal Imaging Probes,

    ADVANCED MATERIALS, Issue 21 2006
    H. Yang
    Multimodal probes of GdIII -functionalized silica-coated CdS:Mn/ZnS quantum dots (see figure) that exhibit yellow fluorescence and strong paramagnetism are reported. High magnetic resonance imaging (MRI) contrast is exhibited by these quantum dots. These properties make for a probe that can operate in multiple modes, which is highly desirable for in,vivo bioimaging applications. [source]


    Fabrication of Stable Low-Density Silica Aerogels Containing Luminescent ZnS Capped CdSe Quantum Dots,

    ADVANCED MATERIALS, Issue 15 2006
    L. Sorensen
    Luminescent CdSe quantum dots of 2.5 and 6.0,nm dimension have been incorporated into a low-density silica aerogels matrix. The aerogels are formed from the supercritical CO2 extraction of an alcogel containing quantum dots surface passivated with 3-aminopropyltriethoxysilane. The resulting aerogels (see figure and cover) are low scattering and show intense, stable luminescence. [source]


    Templated and Hierarchical Assembly of CdSe/ZnS Quantum Dots,

    ADVANCED MATERIALS, Issue 15 2004
    Y. Babayan
    CdSe/ZnS nanocrystals have been assembled into mesoscale structures (see Figure). Templates with dimensions down to 100,nm are generated via phase-shifting photolithography using composite poly(dimethylsiloxane) masks. Upon removal of the template, the CdSe/ZnS structures are found to exhibit hierarchical order over square nanometers (self-assembly of nanocrystals), square micrometers (template shape), and square centimeters (arrays of template pattern). [source]


    2nd International Conference on Semiconductor Quantum Dots (QD 2002) in Tokyo, Japan, 30 September,3 October 2002

    PHYSICA STATUS SOLIDI (B) BASIC SOLID STATE PHYSICS, Issue 2 2003
    R. Heitz
    No abstract is available for this article. [source]