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Search results for: Quantum dots
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Quantum dots in gas sensing a review
PublicationAir pollution becomes an increasing problem in the recent years. There is a need to develop more sensitive gas sensors. Much effort has been performed to develop different types of gas sensors, such as electrochemical sensors or polymer sensors. One of the most promising approaches to improve sensors performance is the application of the nanostructures as sensing materials. State of the art of quantum...
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Quantum dots for photocatalysis: synthesis and environmental applications
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Two-electron entanglement in elliptically deformed quantum dots
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Correlation and Entanglement in Elliptically Deformed Two-Electron Quantum Dots
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Sharp transitions in low-number quantum dots Bayesian magnetometry
PublicationWe consider Bayesian estimate of static magnetic field, characterized by a prior Gaussian probability distribution, in systems of a few electron quantum dot spins interacting with infinite temperature spin environment via hyperfine interaction. Sudden transitions among optimal states and measurements are observed. Usefulness of measuring occupation levels is shown for all times of the evolution, together with the role of entanglement...
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Natural carbon-based quantum dots and their applications in drug delivery: A review
PublicationNatural carbon based quantum dots (NCDs) are an emerging class of nanomaterials in the carbon family. NCDs have gained immense acclamation among researchers because of their abundance, eco-friendly nature, aqueous solubility, the diverse functionality and biocompatibility when compared to other conventional carbon quantum dots (CDs).The presence of different functional groups on the surface of NCDs such as thiol, carboxyl, hydroxyl,...
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Natural carbon-based quantum dots and their applications in drug delivery: A review
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Fabrication of Durable Ordered Ta2O5 Nanotube Arrays Decorated with Bi2S3 Quantum Dots
PublicationOne of the most important challenges in the fabrication of ordered tantalum pentaoxide (Ta2O5) nanotube arrays (NTs) via the electrochemical method is the formation of nanotubes that adhere well to the Ta substrate. In this paper, we propose a new protocol that allows tight-fitting Ta2O5 nanotubes to be obtained through the anodic oxidation of tantalum foil. Moreover, to enhance their activity in the photocatalytic reaction, in...
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Optical and photocatalytic properties of rare earth metal-modified ZnO quantum dots
PublicationA series of novel ZnO quantum dots modified with rare earth metals was successfully prepared by a simple sol-gel approach. The effects of types (Eu, Er, Tb, Yb, Ho, La) and amounts (from 0.09 to 0.45 mmol) of lanthanides on the optical properties, structural characterization and photocatalytic activity of ZnO/RE QDs were systematically investigated. The X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Fourier transform...
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Fabrication of Durable Ordered Ta2O5 Nanotube Arrays Decorated with Bi2S3 Quantum Dots
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Optical and photocatalytic properties of rare earth metal-modified ZnO quantum dots
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Entanglement in S states of two-electron quantum dots with Coulomb impurities at the center
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Synergy between AgInS2 quantum dots and ZnO nanopyramids for photocatalytic hydrogen evolution and phenol degradation
PublicationDespite the unique properties of single semiconductor nanomaterials and quantum dots, poor photocatalytic activity has characterized them and the fabrication of nanocomposites has become necessary to enhance their photocatalytic performance. Thus, AgInS2 quantum dots (AIS QDs, 4.0±1.6 nm), have been successfully prepared and loaded onto ZnO nanopyramids (ZnO NPy). The effect of the nominal amount of AIS QDs decorating ZnO NPy on...
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Effect of selective doping on the spatial dispersion of donor-induced quantum dots in Si nanoscale transistors
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Stannates, titanates and tantalates modified with carbon and graphene quantum dots for enhancement of visible-light photocatalytic activity
PublicationMost efforts in heterogeneous photocatalysis are focused on development of new and stable photoactive materials efficient in degradation of various pollutants under visible-light irradiation. In this regard, the wide-bandgap perovskite semiconductors, i.e., SrTiO3 (titanate), SrSnO3 (stannate) and AgTaO3 (tantalate), were prepared by a solvothermal method, and then modified with carbon quantum dots (CQDs) or graphene quantum dots...
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Remarkable visible-light induced hydrogen generation with ZnIn2S4 microspheres/CuInS2 quantum dots photocatalytic system
PublicationA new and active material in the form of ZnIn2S4 microspheres decorated by CuInS2 quantum dots have been obtained by hydrothermal method for the first time. The optimum amount of CuInS2 quantum dots (1.13 wt.%) introduced into rection medium during ZnIn2S4 microspheres synthesis increased the photocatalytic H2 generation rate by 2.5 times than that of bare ZnIn2S4 photocatalysis under visible light irradiation. This sample exhibited...
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A magnetic imprinted polymer nano-adsorbent with embedded quantum dots and mesoporous carbon for the microextraction of triazine herbicides
PublicationA magnetic molecularly imprinted polymer (MMIP) adsorbent incorporating amino-functionalized magnetite nanoparticles, nitrogen-doped graphene quantum dots and mesoporous carbon (MIP@MPC@NGQDs@ Fe3O4–NH2) was fabricated to extract triazine herbicides from fruit juice. The embedded magnetite nanoparticles simplified the isolation of the adsorbent from the sample solution. The N-GQDs and MPC enhanced adsorption by affinity binding...
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Urchin-like TiO2 structures decorated with lanthanide-doped Bi2S3 quantum dots to boost hydrogen photogeneration performance
PublicationThe formation of heterojunctions between wide- and narrow-bandgap photocatalysts is commonly employed to boost the efficiency of photocatalytic hydrogen generation. Herein, the photoactivity of urchin-like rutile particles is increased by decorating with pristine as well as Er- or Yb-doped Bi2S3 quantum dots (QDs) at varied QD loadings (1–20 wt%) and doping degrees (1–15 mol%), and the best hydrogen evolution performance is achieved at...
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Highly Visible-Light-Photoactive Heterojunction Based on TiO2 Nanotubes Decorated by Pt Nanoparticles and Bi2S3 Quantum Dots
PublicationA heterojunction with excellent visible light response and stability based on titanium dioxide nanotubes (TiO2 NTs), bismuth sulfide quantum dots (Bi2S3 QDs), and platinum nanoparticles (Pt NPs) is proposed. Both Pt NPs (3.0 ± 0.2 nm) and Bi2S3 QDs (3.50 ± 0.20 nm) are well distributed on the (i) top parts, (ii) inner walls, and (iii) outer walls of the TiO2 NTs. Visible-light-induced photoreaction was initialized by excitation...
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Core/Shell Quantum Dots Encapsulated in Biocompatible Oil-Core Nanocarriers as Two-Photon Fluorescent Markers for Bioimaging
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Foliate-Targeting Quantum Dots-β-Cyclodextrin Nanocarrier for Efficient Delivery of Unsymmetrical Bisacridines to Lung and Prostate Cancer Cells
PublicationTargeted drug delivery by nanocarriers molecules can increase the efficiency of cancer treatment. One of the targeting ligands is folic acid (FA), which has a high affinity for the folic acid receptors, which are overexpressed in many cancers. Herein, we describe the preparation of the nanoconjugates containing quantum dots (QDs) and β-cyclodextrin (β-CD) with foliate-targeting properties for the delivery of anticancer compound...
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Quantum Dots as a Good Carriers of Unsymmetrical Bisacridines for Modulating Cellular Uptake and the Biological Response in Lung and Colon Cancer Cells
PublicationNanotechnology-based drug delivery provides a promising area for improving the efficacy of cancer treatments. Therefore, we investigate the potential of using quantum dots (QDs) as drug carriers for antitumor unsymmetrical bisacridine derivatives (UAs) to cancer cells. We examine the influence of QD–UA hybrids on the cellular uptake, internalization (Confocal Laser Scanning Microscope), and the biological response (flow cytometry...
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The Effect of AgInS2, SnS, CuS2, Bi2S3 Quantum Dots on the Surface Properties and Photocatalytic Activity of QDs-Sensitized TiO2 Composite
PublicationThe eect of type (AgInS2, SnS, CuS2, Bi2S3) and amount (5, 10, 15 wt%) of quantum dots (QDs) on the surface properties and photocatalytic activity of QDs-sensitized TiO2 composite, was investigated. AgInS2, SnS, CuS2, Bi2S3 QDs were obtained by hot-injection, sonochemical, microwave, and hot-injection method, respectively. To characterize of as-prepared samples high-resolution transmission electron microscopy (HRTEM), scanning...
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Anti-fouling and permeable polyvinyl chloride nanofiltration membranes embedded by hydrophilic graphene quantum dots for dye wastewater treatment
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Ti/TiO2 nanotubes sensitized PbS quantum dots as photoelectrodes applied for decomposition of anticancer drugs under simulated solar energy
PublicationOne of the challenges in research into photoelectrocatalytic (PEC) degradation of pollutants is finding the appropriate photoanode material, which has a significant impact on the process efficiency. Among all others, photoelectrodes based on an ordered TiO2 nanotube arrays are a promising material due to well-developed surface area and efficient charge separation. To increase the PEC activity of this material, the SILAR method was...
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The effects of bifunctional linker and reflux time on the surface properties and photocatalytic activity of CdTe quantum dots decorated KTaO3 composite photocatalysts
PublicationNovel CdTe-KTaO3composite photocatalysts were successfully synthesized by using thioglycolic acid(TGA) or 3-mercaptopropionic acid (MPA) as linker molecules which facilitated attachment of CdTequantum dots to the surface of KTaO3nanocubes. The as-prepared photocatalysts were characterizedby UV–vis diffuse reflectance spectroscopy (DRS), X-ray diffraction (XRD), scanning electron microscopy(SEM), transmission electron microscopy...
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Effect of synthesis method parameters on properties and photoelectrocatalytic activity under solar irradiation of TiO2 nanotubes decorated with CdS quantum dots
PublicationThe growing research interest on photoelectrocatalysis has encouraged the search for new materials with high activity and the development of methods for their synthesis. The successive ionic layer adsorption and reaction (SILAR) method is an effective way to synthesize materials with photoelectrocatalytic (PEC) properties that are active under visible radiation. Therefore, studies on the impact of the parameters of the SILAR method...
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Preparation and photocatalytic properties of BaZrO 3 and SrZrO 3 modified with Cu 2 O/Bi 2 O 3 quantum dots
PublicationIn this study, we report a novel method of BaZrO3 and SrZrO3 surface modification by two different types of quantum dots (QDs, Cu2O and Bi2O3), which improved the photocatalytic performance of the obtained materials under UV-Vis light irradiation. Pristine BaZrO3 and SrZrO3 were prepared by the hydrothermal method. The deposition of Cu2O- and Bi2O3-QDs was carried out by chemical reduction. The morphology of the nanoparticles was...
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Quantum dots conjugates with unsymmetrical bisacridines enhance cytotoxicity of these antitumor compounds in lung cancer cells and have protecting effects on normal cells
PublicationBackground: In recent years, with the rapid development of nanotechnology and its extensive applications in the medicine, nanocarriers for anticancer drug delivery have gained a great importance. Spherical semiconductor nanocrystals, frequently called quantum dots (QDs) are very attractive nanomaterials for bioimaging applications and they possess properties as potential candidates for drug carrier. Unsymmetrical bisacridines (UAs),...
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Comparative study of donor-induced quantum dots in Si nano-channels by single-electron transport characterization and Kelvin probe force microscopy
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Experimental and DFT insights into an eco-friendly photocatalytic system toward environmental remediation and hydrogen generation based on AgInS2 quantum dots embedded on Bi2WO6
PublicationBismuth tungstate (Bi2WO6) can work as a photocatalyst but suffers from rapid recombination of photogenerated charge carriers. Herein, density functional theory (DFT) simulations revealed that the formation of a thermodynamically stable AgInS2(112)/Bi2WO6(010) heterojunction could promote charge separation and enhance the photoactivity of Bi2WO6. To confirm these theoretical predictions, a new type of photocatalysts in the form...
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Capping ligand initiated CuInS2 quantum dots decoration on, ZnIn2S4 microspheres surface under different alkalinity levels resulting in different hydrogen evolution performance
PublicationSurface distribution of quantum dots (QDs) at the semiconductor matrix caused by synthesis condition (e.g. pH of solution during coupling) could lead to different photocatalytic activity. Thus, achieving an optimal covering of semiconductor matrix by QDs has been challenging. Herein, the influence of the alkalinity level of aqueous decoration medium for the coupling of mercaptoundecanoic acid (MUA) capped CuInS2 quantum dots (CIS)...
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New Unsymmetrical Bisacridine Derivatives Noncovalently Attached to Quaternary Quantum Dots Improve Cancer Therapy by Enhancing Cytotoxicity toward Cancer Cells and Protecting Normal Cells
PublicationThe use of nanoparticles for the controlled drug delivery to cells has emerged as a good alternative to traditional systemic delivery. Quantum dots (QDs) offer potentially invaluable societal benefits such as drug targeting and in vivo biomedical imaging. In contrast, QDs may also pose risks to human health and the environment under certain conditions. Here, we demonstrated that unique combination of nanocrystals core components...
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Quantum and carbon dots conjugated molecularly imprinted polymers as advanced nanomaterials for selective recognition of analytes in environmental, food and biomedical applications
PublicationSamples with complex matrix analyzed during explanation of pathogenesis of various diseases and food or environmental monitoring request advanced analytical and instrumental devices. Among the materials used for described purposes, quantum (QDs) or carbon dots (CDs) layered by molecularly imprinted polymer (MIP) shells have gained widespread attention. Unique optical and physicochemical properties of QDs/CDs together with high...
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Cytotoxicity of C-2028, QDgreen-FA, QDred-FA, QDgreen-FA-C-2028 and QDred-FA-C-2028 aginst H460 cancer cells
Open Research DataThis study presents absorbance values of formazan product (converted from MTT) which corresponds the cytotoxicity of C-2028, QDgreen-FA, QDred-FA, QDgreen-FA-C-2028 and QDred-FA-C-2028 aginst H460 cancer cells. FA (folic acid) was used as a linker between quantum dots (QDs) and compound (C-2028) at different concentration (50-200 µM).
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Cytotoxicity of QDgreen-holo-Tf, QDred-holo-Tf, QDgreen-holo-Tf-C-2028 and QDred-holo-Tf-C-2028 aginst H460 cancer cells_method of synthesis 1
Open Research DataThis study presents absorbance values of formazan product (converted from MTT) which corresponds the cytotoxicity of QDgreen-holo-Tf, QDred-holo-Tf, QDgreen-holo-Tf-C-2028 and QDred-holo-Tf-C-2028 aginst H460 cancer cells (method of synthesis 1). Holo-Tf (transferrin) was used as a linker between quantum dots (QDs) and compound (C-2028).
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Cytotoxicity of C-2028, QDgreen, QDred, QDgreen-FA, QDred-FA, QDgreen-FA-C-2028 and QDred-FA-C-2028 aginst LNCaP cancer cells
Open Research DataThis study presents absorbance values of formazan product (converted from MTT) which corresponds the cytotoxicity of C-2028, QDgreen, QDred, QDgreen-FA, QDred-FA, QDgreen-FA-C-2028 and QDred-FA-C-2028 aginst LNCaP cancer cells. FA (folic acid) was used as a linker between quantum dots (QDs) and compound (C-2028) at different concentration (50-200 µM).
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Cytotoxicity of C-2028, QDgreen, QDred, QDgreen-FA, QDred-FA, QDgreen-FA-C-2028 and QDred-FA-C-2028 aginst Du-145 cancer cells
Open Research DataThis study presents absorbance values of formazan product (converted from MTT) which corresponds the cytotoxicity of C-2028, QDgreen, QDred, QDgreen-FA, QDred-FA, QDgreen-FA-C-2028 and QDred-FA-C-2028 aginst H460 cancer cells. FA (folic acid) was used as a linker between quantum dots (QDs) and compound (C-2028) at different concentration (50-200 µM).
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Cytotoxicity of C-2028, QDgreen, QDred, QDgreen-CD-FA, QDred-CD-FA, QDgreen-CD-FA-C-2028 and QDred-CD-FA-C-2028 aginst LNCaP cancer cells
Open Research DataTis study presents absorbance values of formazan product (converted from MTT) which corresponds the cytotoxicity of C-2028, QDgreen, QDred, QDgreen-CD-FA, QDred-CD-FA, QDgreen-CD-FA-C-2028 and QDred-CD-FA-C-2028 aginst LNCaP cancer cells. FA (folic acid) with cyclodextrin (CD) was used as a linker between quantum dots (QDs) and compound (C-2028).
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Cytotoxicity of C-2028, QDgreen, QDred, QDgreen-CD-FA, QDred-CD-FA, QDgreen-CD-FA-C-2028 and QDred-CD-FA-C-2028 aginst Du-145 cancer cells
Open Research DataTis study presents absorbance values of formazan product (converted from MTT) which corresponds the cytotoxicity of C-2028, QDgreen, QDred, QDgreen-CD-FA, QDred-CD-FA, QDgreen-CD-FA-C-2028 and QDred-CD-FA-C-2028 aginst LNCaP cancer cells. FA (folic acid) with cyclodextrin (CD) was used as a linker between quantum dots (QDs) and compound (C-2028).
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Cytotoxicity of C-2028, QDgreen, QDred, QDgreen-CD-FA, QDred-CD-FA, QDgreen-CD-FA-C-2028 and QDred-CD-FA-C-2028 aginst H460 cancer cells
Open Research DataThis study presents absorbance values of formazan product (converted from MTT) which corresponds the cytotoxicity of C-2028, QDgreen, QDred, QDgreen-CD-FA, QDred-CD-FA, QDgreen-CD-FA-C-2028 and QDred-CD-FA-C-2028 aginst H460 cancer cells. FA (folic acid) with cyclodextrin (CD) was used as a linker between quantum dots (QDs) and compound (C-2028).
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Cytotoxicity of C-2028, QDgreen, QDred, QDgreen-CD-FA, QDred-CD-FA, QDgreen-CD-FA-C-2028 and QDred-CD-FA-C-2028 aginst MRC-5 normal cells
Open Research DataTis study presents absorbance values of formazan product (converted from MTT) which corresponds the cytotoxicity of C-2028, QDgreen, QDred, QDgreen-CD-FA, QDred-CD-FA, QDgreen-CD-FA-C-2028 and QDred-CD-FA-C-2028 aginst MRC-5 normal cells. FA (folic acid) with cyclodextrin (CD) was used as a linker between quantum dots (QDs) and compound (C-2028).
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Cytotoxicity of QDgreen-holo-Tf-C-2028 and QDred-holo-Tf-C-2028 aginst H460 cancer cells_method of synthesis 2
Open Research DataThis study presents absorbance of formazan product (converted from MTT) which corresponds the cytotoxicity of QDgreen-holo-Tf-C-2028 and QDred-holo-Tf-C-2028 aginst H460 cancer cells (method of synthesis 2). Holo-Tf (transferrin) was used as a linker between quantum dots (QDs) and compound (C-2028).
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Cytotoxicity of QDgreen-holo-Tf-C-2028 and QDred-holo-Tf-C-2028 aginst H460 cancer cells_method of synthesis 3
Open Research DataThis study presents absorbance of formazan product (converted from MTT) which corresponds the cytotoxicity of QDgreen-holo-Tf-C-2028 and QDred-holo-Tf-C-2028 aginst H460 cancer cells (method of synthesis 3). Holo-Tf (transferrin) was used as a linker between quantum dots (QDs) and compound (C-2028).
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Design, Synthesis, and Enzymatic Evaluation of Novel ZnO Quantum Dot-Based Assay for Detection of Proteinase 3 Activity
PublicationHerein, the synthesis and application of functionalized quantum dot-based protease probes is described. Such probes are composed of nontoxic ZnO nanocrystals decorated by amino groups followed by linker and labeled peptide attachment. Spherical NH2-terminated ZnO quantum dots (QDs) with the average size ranging from 4 to 8 nm and strong emission centered at 530 nm were prepared using the sol−gel method. The fluorescence of ZnO...
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N-doped graphene quantum dot-decorated MOF-derived yolk-shell ZnO/NiO hybrids to boost lithium and sodium ion battery performance
PublicationSurface engineering at the nanoscale to obtain robust interface between metal oxides and quantum dots is essential for improving the performance and stability of battery materials. Herein, we designed and prepared novel N-doped graphene quantum dot-modified ZnO/NiO anode materials with a well-defined yolk-shell structure for lithium and sodium-ion batteries. NG QDs were assembled on the ZnO/NiO microspheres using three different...
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Sudden death of effective entanglement
PublicationSudden death of entanglement is a well-known effect resulting from the finite volume of separable states. We study the case when the observer has a limited measurement capability and analyze the effective entanglement (i.e., entanglement minimized over the output data). We show that in the well-defined system of two quantum dots monitored by single-electron transistors, one may observe a sudden death of effective entanglement when...
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Nanostructures fabrication with use of electrical AFM litography
Open Research DataIn the last 10 years, one of the nanotechnological trends has been observed, consisting in the development of new variants of computer memory systems with high capacity and speed of access, using quantum dots. One of the techniques for creating nanodots and other nanostructures is based on the use of an atomic force microscope acting as a lithographic...
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Superconductivity and appearance of negative magnetocaloric effect in Ba1–xKxBiO3 perovskites, doped by Y, La and Pr
PublicationRecently, substantial attention is given to the bismuth-based perovskites for variety of electronic applications. The perovskites are used for quantum dots displays (QLED), photovoltaic systems and superconducting (HTS) devices. In this paper comprehensive studies of Ba1–xKxBi1–yREyO3 bismuth perovskites (REBKBO, RE = Y , La or Pr) are reported. Apart from structural anomalous behavior at low temperatures, the electronic properties...
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Stable nanoconjugates of transferrin with alloyed quaternary nanocrystals Ag–In–Zn–S as a biological entity for tumor recognition
PublicationOne way to limit the negative effects of anti-tumor drugs on healthy cells is targeted therapy employing functionalized drug carriers. Here we present a biocompatible and stable nanoconjugate of transferrin anchored to Ag-In-Zn-S quantum dots modified with 11-mercaptoundecanoic acid (Tf-QD) as a drug carrier versus typical anticancer drug, doxorubicin. Detailed investigations of Tf-QD nanoconjugates without and with doxorubicin...