Dalian University of Technology

About: Dalian University of Technology is a education organization based out in Dalian, China. It is known for research contribution in the topics: Catalysis & Finite element method. The organization has 60890 authors who have published 71921 publications receiving 1188356 citations. The organization is also known as: Dàlián Lǐgōng Dàxué.

Carbon Dots with Red Emission for Sensing of Pt2+, Au3+, and Pd2+ and Their Bioapplications in Vitro and in Vivo

Abstract: Red emissive carbon dots (CDs) have drawn more and more attention due to their good organ penetration depth and slight biological tissue photodamage. Herein, the fluorescent CDs with red emission were synthesized by the facile one-pot hydrothermal treatment of citric acid and neutral red and they show red fluorescence both in aqueous solution and solid state. The solution of CDs exhibits the quantum yield of 12.1%, good stability against photobleaching, and low cytotoxicity. As-prepared CDs can be used as a fluorescent probe for peculiar detection of Pt2+, Au3+, and Pd2+. Furthermore, the CDs show excellent biocompatibility, which were successfully used as hopeful bioimaging and biosensing of noble metal ions in PC12 cells and zebrafish.

Support Vector Echo-State Machine for Chaotic Time-Series Prediction

Abstract: A novel chaotic time-series prediction method based on support vector machines (SVMs) and echo-state mechanisms is proposed. The basic idea is replacing "kernel trick" with "reservoir trick" in dealing with nonlinearity, that is, performing linear support vector regression (SVR) in the high-dimension "reservoir" state space, and the solution benefits from the advantages from structural risk minimization principle, and we call it support vector echo-state machines (SVESMs). SVESMs belong to a special kind of recurrent neural networks (RNNs) with convex objective function, and their solution is global, optimal, and unique. SVESMs are especially efficient in dealing with real life nonlinear time series, and its generalization ability and robustness are obtained by regularization operator and robust loss function. The method is tested on the benchmark prediction problem of Mackey-Glass time series and applied to some real life time series such as monthly sunspots time series and runoff time series of the Yellow River, and the prediction results are promising

A highly selective red-emitting FRET fluorescent molecular probe derived from BODIPY for the detection of cysteine and homocysteine: an experimental and theoretical study

Abstract: A red-emitting BODIPY-based fluorescent-resonance-energy-transfer (FRET) molecular probe 1 for selective detection of cysteine and homocysteine was designed. The fluorescence OFF–ON switch is triggered by cleavage of the 2,4-dinitrobenzensulfonyl (DNBS) unit from the fluorophore by thiols. The FRET energy donor (λabs = 498 nm, λem = 511 nm) is a parent BODIPY moiety and the energy acceptor is based on 4-hydroxylstyryl BODIPY moiety (λabs = 568 nm, λem = 586 nm). The unique C–C linker between the energy donor and acceptor was established using a Suzuki cross-coupling reaction. A polyether chain was also introduced into the probe to improve solubility in aqueous solution. While probe 1 itself is non-fluorescent, in the presence of cysteine or homocysteine a red emission at 590 nm is switched on (excitation at 505 nm), producing a pseudo-Stokes shift of up to 77 nm, which is in stark contrast to the small Stokes shift (ca. 10 nm) observed for typical BODIPY dyes. Excitation of the energy donor leads to the red emission from the acceptor of the probe, and demonstrates a high energy transfer efficiency. The probe was used for in vivo fluorescent imaging of cellular thiols. The fluorescence sensing mechanism of the probe and the photophysical properties of the fluorescent intermediates were fully rationalized by DFT calculations. The lack of fluorescence of probe 1 is attributed to the dark excited state S1 (oscillator strength f = 0.0007 for S0 → S1, based on the optimized S1 state geometry), which is due to the electron sink effect of the DNBS moiety. Cleavage of the DNBS moiety from the fluorophore by thiols re-establishes the emissive S1 state of the fluorophore (f = 1.4317 for S0 → S1), thus the red emission can be observed in the presence of thiols (fluorescence is turned on). The FRET effect of the probe was rationalized by DFT calculations which indicated that upon excitation into the S4 excited state (localized on the energy donor unit), the S1 state (localized on the energy acceptor, i.e. styryl-BODIPY) is populated via internal conversion (IC), thus red emission from the styryl-BODIPY energy acceptor is observed (Kasha's rule).

Vertically Aligned Oxygenated-CoS2–MoS2 Heteronanosheet Architecture from Polyoxometalate for Efficient and Stable Overall Water Splitting

Abstract: To achieve efficient conversion of renewable energy sources through water splitting, low-cost, earth-abundant, and robust electrocatalysts for the oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) are required. Herein, vertically aligned oxygenated-CoS2–MoS2 (O-CoMoS) heteronanosheets grown on flexible carbon fiber cloth as bifunctional electrocatalysts have been produced by use of the Anderson-type (NH4)4[CoIIMo6O24H6]·6H2O polyoxometalate as bimetal precursor. In comparison to different O-FeMoS, O-NiMoS, and MoS2 nanosheet arrays, the O-CoMoS heteronanosheet array exhibited low overpotentials of 97 and 272 mV to reach a current density of 10 mA cm–2 in alkaline solution for the HER and OER, respectively. Assembled as an electrolyzer for overall water splitting, O-CoMoS heteronanosheets as both the anode and cathode deliver a current density of 10 mA cm–2 at a quite low cell voltage of 1.6 V. This O-CoMoS architecture is highly advantageous for a disordered structure, exposure of acti...