Electrochemical biosensor for detection of ampicillin in milk based on AuPt and DNA cycle dual-signal amplification strategy.

A biosensor is reported for electrochemical detection of ampicillin based on AuPt and DNA cycle dual-signal amplification strategy. Firstly, AuPt is prepared by reduction of chloroauric acid and chloroplatinic acid with serine-functionalized graphene quantum dot (SGQD). The resulting AuPt shows an excellent catalytic activity because of the synergy of Au and Pt.

Synthesis of histidine, serine and folic acid-functionalized and boron and iron-doped graphene quantum dot with excellent optical behavior and peroxidase-like activity for colorimetric and fluorescence detection of HO in food.

Low fluorescence under visible light excitation and catalytic activity limit many applications of graphene quantum dots in optical detection, biosensing, catalysis and biomedical. The paper reports design and synthesis of histidine, serine and folic acid-functionalized and boron and iron-doped graphene quantum dot (Fe/B-GQD-HSF). The Fe/B-GQD-HSF shows excellent fluorescence behavior and peroxidase-like activity.

Self-powered sensing platform for monitoring uric acid in sweat using cobalt nanocrystal-graphene quantum dot-TiCT monolithic film electrode with excellent supercapacitor and sensing behavior.

The synthesis of cobalt nanocrystal-graphene quantum dot-TiCT monolithic film electrode (Co-GQD-TiCT) is reported via self-assembly of TiCT nanosheets induced by protonated arginine-functionalized graphene quantum dot and subsequent reduction of cobalt (III). The resulting Co-GQD-TiCT shows good monolithic architecture, mechanical property, dispersibility and conductivity. The structure achieves excellent supercapacitor and sensing behavior.

Designing of multifunctional graphene quantum dot-polyvinyl alcohol-polyglycerol luminescent film for fluorescence detection of pH in sweat.

Background: Wound infection, skin disease, renal failure, cancer, cystic fibrosis, and other pathologies may induce obvious pH changes in sweat. Thus, tracking skin pH changes can help monitor human health in a convenient manner. Owing to their biocompatibility, easy preparation, and sensitive response to pH changes, graphene quantum dots (GQDs) have received increased attention in the optical detection of pH changes.

Quantitative analysis of a posterior fossa teratomas with unusual CT and MR Characteristics--illustrative case.

Background: Intracranial teratomas or other cystic lesions with atypical imaging manifestations can still be frequently seen clinically. The specific reasons for unusual imaging manifestations need to be further explored.

Observations: A case of adult teratoma in the posterior fossa with unusual imaging manifestations was reported.

Trap remediation of CuBiO nanopolyhedra surface self-coordination by HO: an innovative signaling mode for cathodic photoelectrochemical bioassay.

This work conveys a new philosophy of surface self-coordination mediated trap remediation for innovative cathodic photoelectrochemical (PEC) signal transduction. Initially, the surface trap states of CuBiO nanopolyhedra resulting from dangling bonds can function as charge carrier recombination centers, which suppress the carrier separation efficiency and result in a low photocurrent output. Particularly, hydrogen peroxide (HO) spontaneously interacts with the uncoordinated Cu(II) on the surface of CuBiO, enabling efficient elimination of dangling bonds and remedy of trap states, thereby outputting intensified photocurrent readout.

The Influencing Effect of Tourism Economy on Green Development Efficiency in the Yangtze River Delta.

In the context of ecological priority and green development strategy, accelerating the upgrading of tourism structure and promoting the development of ecotourism is an important guarantee to achieve green and low-carbon economic growth and high-quality development. On the basis of constructing comprehensive evaluation indicators of tourism development (TD) and green development efficiency (GDE), this study analyzed the impulse response relationship between TD and GDE and the impact effect of TD on GDE in the Yangtze River Delta region from 2000-2018. Findings showed that: (1) During the study period, TD generally exhibited a W-shaped fluctuating upward trend and GDE showed a staggered evolution of upward and downward fluctuations, while both regional gaps of TD and GDE continued to decrease.

Highly sensitive and selective electrochemical aptasensor with gold-aspartic acid, glycine acid-functionalized and boron-doped graphene quantum dot nanohybrid for detection of α-amanitin in blood.

Poisonous mushroom may cause fatal harm to human and animal, but its rapid detection still faces a great challenge. The paper reports synthesis of gold-aspartic acid, glycine acid-functionalized and boron-doped graphene quantum dot nanohybrid (AGB-GQD@Au) for the electrochemical detection of α-amanitin. AGB-GQD was prepared by pyrolysis and then reacted with chloroauric acid to produce gold nanoparticles.

Invoking Cathodic Photoelectrochemistry through a Spontaneously Coordinated Electron Transporter: A Proof of Concept Toward Signal Transduction for Bioanalysis.

Most of the cathodic photoelectrochemical (PEC) bioassays rely on electron accepting molecules for signal stimuli; unfortunately, the performances of which are still undesirable. New signal transduction strategies are still highly expected for the further development of cathodic photoelectrochemistry as a potentially competitive method. This work represents a new concept of invoked cathodic photoelectrochemistry by a spontaneously formed electron transporter for innovative operation of the sensing strategy.

Recent Advances in g-C N -Based Photocatalysts for Pollutant Degradation and Bacterial Disinfection: Design Strategies, Mechanisms, and Applications.

Emerging photocatalytic technology promises to provide an effective solution to the global energy crisis and environmental pollution. Graphite carbon nitride (g-C N ) has gained extensive attention in the scientific community due to its excellent physical and chemical properties, attractive electronic band structure, and low cost. In this paper, research progress in design strategies for g-C N -based photocatalysts in the past five years is reviewed from the perspectives of nanostructure construction, element doping, and heterostructure construction.

Eccentricity forcing of East Asian monsoonal systems over the past 3 million years.

The East Asian summer monsoon and the precipitation it brings are relevant for millions of people. Because of the monsoon's importance, there has been a substantial amount of work attempting to describe the driving mechanisms behind its past variability. However, discrepancies exist, with speleothem-based East Asian monsoon reconstructions differing from those based on loess records from the Chinese Loess Plateau during the late Quaternary.

Electrochemical detection of carbendazim with mulberry fruit-like gold nanocrystal/multiple graphene aerogel and DNA cycle amplification.

An aptasensor for electrochemical detection of carbendazim is reported with mulberry fruit-like gold nanocrystal (MF-Au)/multiple graphene aerogel (MGA) and DNA cycle amplification. HAuCl was reduced by ascorbic acid in a CTAC solution containing KBr and KI and formed trioctahedron gold nanocrystal. The gold nanocrystal underwent structural evolution under enantioselective direction of L-cysteine.

Colorimetric detection of chlorpyrifos in peach based on cobalt-graphene nanohybrid with excellent oxidase-like activity and reusability.

Cobalt nanocrystal has been widely used as nano-enzyme for sensing and catalysis due to its high stability and low cost, but poor catalytic activity limits its applications in bioanalysis. The study reports one strategy for synthesis of cobalt-graphene nanohybrid. Histidine-functionalized graphene quantum dot (His-GQD) was bound to graphene sheet via π-π stacking and then combined with cobalt ions in the presence of cetyltrimethylammonium chloride to form stable complex and finally reduced under nitrogen to obtain Co-His-GQD-G.

Establishing Interfacial Charge-Transfer Transitions on Ferroelectric Perovskites: An Efficient Route for Photoelectrochemical Bioanalysis.

This work presents the concept of establishing interfacial charge-transfer transitions (ICTT) on ferroelectric perovskites for efficient photoelectrochemical (PEC) bioanalysis. The model system was exemplified by using representative lead titanate (PbTiO) and an enzyme tandem consisting of the isocitrate dehydrogenase (ICDH) and -hydroxybenzoate hydroxylase (PHBH). The enzymatic generation of protocatechuic acid (PCA) can coordinate onto the surface of the PbTiO and hence form the ICTT that enables direct ligand-to-metal charge transfer from the highest occupied molecular orbital (HOMO) of PCA to the conduction band (CB) of PbTiO under light irradiation.

A 2D donor-acceptor covalent organic framework with charge transfer for supercapacitors.

An electron donor-acceptor covalent organic framework (TTF-COF1) was constructed by the imine condensation of electron donor tetraformyl-tetrathiafulvalene (TTF-fo) and electron acceptor 2,6-diaminoanthraquinone (DAQ). TTF-COF1 has intramolecular charge transfer, offering capacitance of 752 F g at 1 A g and an energy density of 57 W h kg at a power density of 858 W kg.