Ultrasensitive Fluorescence Detection of Ascorbic Acid Using Silver Ion-Modulated High-Quality CdSe/CdS/ZnS Quantum Dots.

Improving the sensitivity of the fluorescence method for the detection of bioactive molecules is crucial in biochemical analysis. In this work, an ultrasensitive sensing strategy was constructed for the detection of ascorbic acid (AA) using high-quality 3-mercaptopropionic acid-capped CdSe/CdS/ZnS quantum dots (MPA-CdSe/CdS/ZnS QDs) as the fluorescent probe. The prepared water-soluble QDs exhibited a high photoluminescence quantum yield (PL QY) of up to 96%.

DNA tetrahedron-based dual-signal fluorescence detection of apoE4 gene sites on a microplate reader.

As a neurodegenerative disorder, Alzheimer's disease (AD) is characterized by cognitive dysfunction and behavioral impairment. Among the various genetic risk factors for AD, apoE4 gene plays a pivotal role in the onset and progression of AD, and detection of apoE4 gene holds significance for prevention and early diagnosis of AD. Herein, dual-signal fluorescence detection of fragments associated with apoE ε4 allele near codon 112 (Tc1) and codon 158 (Tc2) was achieved using DNA tetrahedron nanostructure (DTN).

Conversion of Photoluminescence Blinking Types in Single Colloidal Quantum Dots.

Almost all colloidal quantum dots (QDs) exhibit undesired photoluminescence (PL) blinking, which poses a significant obstacle to their use in numerous luminescence applications. An in-depth study of the blinking behavior, along with the associated mechanisms, can provide critical opportunities for fabricating high-quality QDs for diverse applications. Here the blinking of a large series of colloidal QDs is investigated with different surface ligands, particle sizes, shell thicknesses, and compositions.

A High-Quality CdSe/CdS/ZnS Quantum-Dot-Based FRET Aptasensor for the Simultaneous Detection of Two Different Alzheimer's Disease Core Biomarkers.

The simultaneous detection of two different biomarkers for the point-of-care diagnosis of major diseases, such as Alzheimer’s disease (AD), is greatly challenging. Due to the outstanding photoluminescence (PL) properties of quantum dots (QDs), a high-quality CdSe/CdS/ZnS QD-based fluorescence resonance energy transfer (FRET) aptasensor for simultaneously monitoring the amyloid-β oligomers (AβO) and tau protein was proposed. By engineering the interior inorganic structure and inorganic−organic interface, water-soluble dual-color CdSe/CdS/ZnS QDs with a near-unity PL quantum yield (>90%) and mono-exponential PL decay dynamics were generated.

Phylogenomics, plastome structure and species identification in Mahonia (Berberidaceae).

Background: Elucidating the phylogenetic relationships within species-rich genera is essential but challenging, especially when lineages are assumed to have been going through radiation events. Mahonia Nutt. (Berberidaceae) is a genus with cosmopolitan distribution, comprising approximately 100 species, two of which are known as Caulis Mahoniae (M.

Effect of 580 °C (20 h) Heat Treatment on Mechanical Properties of 25Cr2NiMo1V Rotor-Welded Joints of Oscillating Arc (MAG) Narrow Gap Thick Steel.

The thick plate narrow gap welding of 25Cr2NiMo1V rotor steel is achieved by metal active gas arc welding, in which the weld gap was 18.04-19.9 mm.

Clinical effect of warm needle penetration in treating knee osteoarthritis.

Objective: Our aim was to explore the clinical effect of warm needle penetration in treating knee osteoarthritis.

Methods: We randomly divided 118 patients with knee osteoarthritis into the observation group (n=59) and the control group (n=59). The observation group was treated with warm needle penetration combined with western medicine therapy, and the control group was only given western medicine therapy.

Evaluation of the effect of a three-color ladder management model for knee osteoarthritis in the community.

Objective: To explore the application effect of a three-color ladder management system for knee osteoarthritis in the community.

Methods: Eighty-six patients with knee osteoarthritis in our community were obtained for study and randomly grouped. The control group received routine management, while the research group received three-color ladder management for 12 months.

Enhancing Dielectric Screening for Auger Suppression in CdSe/CdS Quantum Dots by Epitaxial Growth of ZnS Shell.

Auger recombination is the main nonradiative process in multicarrier states of high-quality quantum dots (QDs). For the most-studied CdSe/CdS core/shell QDs, we effectively reduce the biexciton Auger rate by enhancing dielectric screening of band-edge carriers via epitaxial growth of additional ZnS shells. Super volume scaling of negative-trion Auger lifetime for CdSe/CdS core/shell QDs is achieved with the outermost ZnS shells.

Effects of interface-potential smoothness and wavefunction delocalization on Auger recombination in colloidal CdSe-based core/shell quantum dots.

Auger nonradiative recombination dominates decay of multicarrier states in high quality colloidal quantum dots (QDs) and thus is critical for many of their optical and optoelectronic applications. Controlling interface-potential smoothness and wavefunction delocalization are proposed as two main strategies for Auger engineering in core/shell QDs. Here, a series of CdSe-based core/shell QDs with nearly ideal optical quality of their single-exciton states are developed and applied for studying biexciton quantum yields and Auger nonradiative recombination rates.

Author Correction: Engineering Auger recombination in colloidal quantum dots via dielectric screening.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Engineering Auger recombination in colloidal quantum dots via dielectric screening.

Auger recombination is the main non-radiative decay pathway for multi-carrier states of colloidal quantum dots, which affects performance of most of their optical and optoelectronic applications. Outstanding single-exciton properties of CdSe/CdS core/shell quantum dots enable us to simultaneously study the two basic types of Auger recombination channels-negative trion and positive trion channels. Though Auger rates of positive trion are regarded to be much faster than that of negative trion for II-VI quantum dots in literature, our experiments find the two rates can be inverted for certain core/shell geometries.

Stoichiometry-Controlled InP-Based Quantum Dots: Synthesis, Photoluminescence, and Electroluminescence.

We introduce stoichiometry control within both core and shell regions of InP/ZnSe/ZnS core/shell/shell quantum dots (QDs) to advance their properties drastically, approaching those of state-of-the-art CdSe-based QDs. The resulting QDs possess near-unity photoluminescence quantum yield, monoexponential decay dynamics, narrow line width, and nonblinking at a single-dot level. Quantum-dot light-emitting diodes (QLEDs) with the InP/ZnSe/ZnS core/shell/shell QDs as emitters exhibit a peak external quantum efficiency of 12.

Genetic and chemical differentiation characterizes top-geoherb and non-top-geoherb areas in the TCM herb rhubarb.

Medicinal herbs of high quality and with significant clinical effects have been designated as top-geoherbs in traditional Chinese medicine (TCM). However, the validity of this concept using genetic markers has not been widely tested. In this study, we investigated the genetic variation within the Rheum palmatum complex (rhubarb), an important herbal remedy in TCM, using a phylogeographic (six chloroplast DNA regions, five nuclear DNA regions, and 14 nuclear microsatellite loci) and a chemical approach (anthraquinone content).

Deciphering Charging Status, Absolute Quantum Efficiency, and Absorption Cross Section of Multicarrier States in Single Colloidal Quantum Dots.

Upon photo- or electrical-excitation, colloidal quantum dots (QDs) are often found in multicarrier states due to multiphoton absorption, photocharging, or imbalanced carrier injection of the QDs. While many of these multicarrier states are observed in single-dot spectroscopy, their properties are not well studied due to random charging/discharging, emission intensity intermittency, and uncontrolled surface defects of single QDs. Here we report in situ deciphering of the charging status, precisely assessing the absorption cross section, and determining the absolute emission quantum yield of monoexciton and biexciton states for neutral, positively charged, and negatively charged single core/shell CdSe/CdS QDs.

A Two-Step Synthetic Strategy toward Monodisperse Colloidal CdSe and CdSe/CdS Core/Shell Nanocrystals.

CdSe magic-size clusters with close-shell surface and fixed molecular formula are well-known in the size range between ∼1 and 3 nm. By applying high concentration of cadmium alkanoates as ligands, a conventional synthetic system for CdSe nanocrystals was tuned to discriminate completion from initiation of atomic flat facets. This resulted in ∼4-13 nm CdSe nanocrystals with hexahedral shape terminated with low-index facets, namely three (100), one (110), and two (111) facets.

Morphological variation in leaf dissection of Rheum palmatum complex (Polygonaceae).

Aims: Rheum palmatum complex comprises all taxa within section Palmata in the genus Rheum, including R. officinale, R. palmatum, R.

Genetic variation in Rheum palmatum and Rheum tanguticum (Polygonaceae), two medicinally and endemic species in China using ISSR markers.

Aims: Both Rheum palmatum and R. tanguticum are important but endangered medicinal plants endemic to China. In this study, we aimed to (i) investigate the level and pattern of genetic variability within/among populations of those species; (ii) evaluate genetic differentiation between both species and its relationships and ascertain whether both species are consistent with their current taxonomical treatment as separate species; and (iii) discuss the implications for the effective conservation of two species.

Genetic diversity of the endemic and medicinally important plant Rheum officinale as revealed by Inter-Simpe Sequence Repeat (ISSR) Markers.

Rheum officinale Baill., an important but endangered medicinal herb, is endemic to China. Inter-simple sequence repeat (ISSR) markers were employed to investigate the genetic diversity and differentiation of 12 populations of R.