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Based on the highly specific interaction between concanavalin A (Con A) and glucose (Glu), a competitive electrochemiluminescence (ECL) biosensor was constructed for ultrasensitive detection of Con A. Nanocomposites with excellent electrocatalytic and photothermal properties were obtained by covalently bonding zinc oxide quantum dots (ZnO QDs) to vanadium carbide MXene (V2C MXene) surfaces. The modification of ZnO QDs hinders the aggregation of V2C MXene and increases the catalytic activity of oxygen reduction reaction, thus amplifying the luminol cathodic emission. In addition, the excellent photothermal performance of the V2C MXene-ZnO QDs can convert light energy into heat energy under the irradiation of 808 nm near infrared laser, thus increasing the temperature of the reaction system and accelerating the electron transfer process to realize the synergistic amplified homogeneous ECL system. This innovative work not only enriches the fundamental research on multifunctional MXene nanomaterials for biosensing, but also provides an effective strategy for ECL signal amplification. [ABSTRACT FROM AUTHOR]

The heavy-metal pollution of the consumer-electronics industry has been a serious environmental problem in China. Since 2010, Chinese ENGOs have taken a few measures to address this challenge. Under the influence of other stakeholders, Chinese ENGOs have only played a limited role. To further explore the potential of domestic ENGOs, it would be necessary to understand how they have approached the heavy-metal challenge and why their contribution has been moderate. By using the method of "process tracing," this paper presents a preliminary attempt to trace and generate localized knowledge of Chinese ENGOs' approach and the influence of other stakeholders. Specifically, this paper divides the actions of Chinese ENGOs into the following three phases: initial participation, progressive involvement of MNCs, and collaborative tracking and online disclosure. Then, it traces the participation of Chinese mass media, domestic suppliers, local governments, and communities. It argues that the following six constraining factors have contributed to shaping the limited role of those Chinese ENGOs: (1) the complexity of the consumer-electronics supplier network; (2) Chinese ENGOs' lack of leverage on MNCs; (3) Chinese ENGOs' shortage of financial and human resources under a broad agenda; (4) domestic mass media's lack of long-term interest; (5) reluctant participation of Chinese suppliers and local governments; and (6) conflicting interests within local communities. Three policy options for further exploring the potential of Chinese ENGOs are discussed, including financial and technical support, further engagement of international ENGOs, and supportive policy-making and interregional coordination by local governments. [ABSTRACT FROM AUTHOR]

A fluorescence quenching enhanced immunoassay has been developed to achieve ultrasensitive recognition of human epididymal 4 (HE4) modifying the fluorescence quencher. The carboxymethyl cellulose sodium-functionalized Nb2C MXene nanocomposite (CMC@MXene) was firstly introduced to quench the fluorescence signal of the luminophore Tb-Norfloxacin coordination polymer nanoparticles (Tb-NFX CPNPs). The Nb2C MXene nanocomposite as fluorescent nanoquencher inhibits the electron transfer between Tb and NFX to quench the fluorescent signal by coordinating the strongly electronegative carboxyl group on CMC with Tb (III) of Tb-NFX complex. Simultaneously, due to the superior photothermal conversion capability of CMC@MXene, the fluorescence signal has been further weakened by the photothermal effect driven non-radiative decay of the excited state under near-infrared laser irradiation. The constructed fluorescent biosensor based on CMC@MXene probe finally realized the enhanced fluorescence quenching effect, and achieved ultra-high sensitivity and selective detection of HE4, exhibiting a wide linear relationship with HE4 concentration on the logarithmic axis in the range of 10−5 to 10 ng/mL and a low detection limit of 3.3 fg/mL (S/N = 3). This work not only provides an enhanced fluorescent signal quenching method for the detection of HE4, but also provides novel insights for the design of fluorescent sensor toward different biomolecules. [ABSTRACT FROM AUTHOR]

As China has become the largest greenhouse gas (GHG) emitter in terms of total annual emissions, to promote GHG emissions reduction in China turns out to be crucial to the success of the global efforts to address climate change. This paper explores the development of the Chinese Domestic Voluntary Carbon Market (DVCM) in order to understand how carbon trading institutions have emerged and developed in China. To do this, it traces and analyzes the roles of the Chinese government and other key actors. Through process tracing and literature review, it argues that the pre-legislation and territorially fragmented development pattern of the Chinese DVCM has resulted from the activities of Chinese local governments and non-state actors under the policy experimentation approach adopted by the Chinese central government. It concludes with brief comments on the Chinese policy experimentation approach, and suggests that some measures can be taken to promote voluntary emissions reduction and policy learning. [ABSTRACT FROM AUTHOR]

A dual-readout immunosensor coupled with electrochemical impedance and temperature signal was successfully proposed to detect autoimmune hepatitis markers (ASGPR). Nb2C MXene with excellent conductivity, abundant surface functional groups, and extraordinary photothermal conversion efficiency, was designed to be a multifunctional biological probe, whose specific binding with antigen enhanced steric hindrance to generate electrochemical impedance signal, and at the same time, it had a strong optical response in the near-infrared band to achieve temperature output. In addition, poly(N-isopropyl acrylamide) (PNIPAM) was a temperature-sensitive polymer, which was adopted as the sensing matrix. When the multifunctional probe was specifically bound to the antigen, under 808-nm laser irradiation, the captured Nb2C MXene achieved photothermal conversion to increase the electrode surface temperature, and the conformation of PNIPAM changed from a free spiral to a spherical shape, further realizing double amplification of the EIS signal. Under the optimized experimental conditions, the impedance values and the temperature changes increased proportionally with the increase of the ASGPR concentration from 10−5 to 1 ng/mL, and the detection limit of the immunosensor was 3.3 × 10−6 ng/mL. The established dual-readout immunosensor exhibited good selectivity and acceptable stability and provided an effective detection method for autoimmune hepatitis marker detection. [ABSTRACT FROM AUTHOR]