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Reducing substances play crucial roles in various physiological processes and serve as essential components in the antioxidant defense mechanisms within organisms. Nonetheless, accurately detecting and distinguishing between these substances present a notable challenge due to the presence of potential interferences in complex samples. In response to this challenge, a novel multisignal sensing platform and sensor array have been developed, leveraging fluorescent polydopamine nanoparticles (FPDA) and MnO2 nanozyme. The MnO2/FPDA nanoplatform possesses exceptional catalytic activity and the ability to modulate ratiometric fluorescence in the presence of o-phenylenediamine (OPD), offering a platform with dual-channel output signals in ratiometric fluorescence and UV absorbance. Upon introduction of H2O2, the MnO2 undergoes transformation into Mn2+, thereby reducing the oxidase-like activity of MnO2 and reinstating the fluorescence of FPDA. Notably, this platform exhibits detection ranges for H2O2 from 5 to 500 and 15 to 500 μM, with corresponding detection limits of 3.18 and 10.67 μM using fluorescence and colorimetric channels, respectively. This setup has been deployed for quantifying H2O2 in milk and cell lysates, showcasing its versatility as a universal analysis tool for other reducing agents like ascorbic acid. Furthermore, a sensor array has been developed based on MnO2/FPDA/OPD, demonstrating a robust capacity to effectively differentiate and identify five reducing agents effectively. This sensor array also exhibits strong performance in discriminating reducing substances within intricate or authentic samples, such as oranges and cell lysates, underscores its practical utility. This study offers significant insights into the development of sensing platforms for the selectively detecting specific reducing species in real samples or deploying sensor arrays for distinguishing multiple components within authentic samples. Such advancements pave the way for enhanced analysis and screening of reducing substances in cellular and food samples. [ABSTRACT FROM AUTHOR]

The studies about the seven-coordinate iron and manganese complexes with the acyclic and rigid [H.sub.2]dapsox (2,6-diacetylpyridinebis(semioxamazide)) ligand which demonstrate their ability to catalytically decompose superoxide is presented.

The analysis and characterization of Ru(II) compounds are described. It is found that these compounds exhibited a single quasi-reversible Ru(super III)/(super II) wave and legand-localized waves corresponding to the sequential reduction of the dimine ligans

One-pot total syntheses of the quinazolinobenzodiazepine alkaloids sclerotigenin (plusmn) circumdatin F, and (plusmn)-asperlicin C via novel microwave-assisted domino reactions are achieved in 55%, 32% and 20% yields, respectively, from commercially available starting materials. A two-step total synthesis of (plusmn)-benzomalvin A is accomplished with an overall yield of 16%.

The structures and energies of hydrated oxalate clusters, C2O4(super 2-)(H2O)n, n = 6-12, are obtained by density functional theory (DFT) calculations and compared to SO4(super 2-)(H2O)n. A number of important and distinctive futures in C2O4(super 2-)(H2O)n that affect both the structure and the solvation energy are present.

Grb10 is a direct substrate of mitogen-activated protein kinase. In vivo labeling and two-dimensional phosphoeptide mapping studies revealed Ser(super 150) and Ser(super 476) of human Grb10zeta as two in vivo phosphorylation sites.

Planewave/ pseudopotential-based density functional theory is used to analyze the chemisorption of singlet O2 on the sidewall of a series of zigzag (n,0) Single Walled Carbon Nanotubes (SWNTs) (n=6 -15). The results suggested that by introducing two epoxy groups onto the wall of the carbon nanotubes of 1nm diameter, through oxidation reaction with singlet O2, provide possibility of chemical functionalization and cause complete breaking of C-C bond near the adsorption sites.

The utilization of lithium, valproic acid (VPA) and molecular biology tools, such as glycogen synthase kinase 3beta (GSK3beta) kinase-deficient construct, GSK3beta antisense oligonucleotide (ASO) and GSK3beta transgenic, to investigate the involvement of GSK3beta activity in amyloid precursor protein (APP) processing that is observed in HEK293 cells and in the brains of PDAPP transgenic mice are reported. Lithium is one of the most widely used mood-stabilizing agents for the treatment of bipolar disorder.

The chemisorption of NO2 on carbon nanotubes is studied by modeling the interaction between NO2 and N2O4 with an infinitely long (8,0) single-walled carbon nanotube, using planewave/pseudopotential-based density functional theory (DFT). The results indicate that the (8,0) tube is more reactive toward NO2 than graphite, due to the curvature on the rolled graphene sheet.

This study has developed two interfaces to connect small-size thin-layer chromatography (TLC) with electrospray ionization mass spectrometry (ES-MS) for the continuous analysis of organic mixtures. The interfaces are (1) two bound optical fibers inserted into the C18-bonded particles at the exit of a small TLC channel and (2) a small commercial TLC strip with a sharpened tip. A reservoir continuously supplied a makeup solution to the tip of the TLC channel. The high voltage required for electrospray ionization was introduced into the makeup solution or mobile phase through a Pt wire, and electrospray was generated at the tip of the bonded optical fibers and at the sharp end of the TLC strip. Since small-size TLC channels were used, the elution time was short and less than 0.2 [micro]L of the sample solution and 200 [micro]L of the eluting solvent were required. Organic mixtures were separated successfully and detected on-line using the TLC/ES-MS techniques.

Excessive exposure to ultraviolet (UV) rays in sunlight is harmful to human skin. The development of an intelligent UV monitor that can detect the solar UV intensity in real time is highly desirable for human health and safety. In this work, a sunlight-responsive paper-based color-switching film (PCSF) is developed by combining color-switchable titania/hydrated tungsten oxide (THTO) heteronanoparticles with a sticker paper substrate. The THTO heteronanoparticles with an average size of 10 nm are distributed tightly on the surface of the paper substrate. Owing to the advantages of the excellent sensitivity and selectivity to solar UV radiation of THTO heteronanoparticles and the high flexibility of the paper substrate, the PCSF shows great potential for solar UV radiation monitors. With the solar UV intensity increasing from 0.75 to 3.25 mW·cm-2, the color of PCSF changes from colorless to blue and even dark blue. Moreover, the color change of the PCSF under solar UV irradiation featuring 40 s is calibrated to indicate the solar UV radiation intensity. Taking the advantage of the excellent sensitivity and selectivity to solar UV radiation, high reversibility, flexibility, and low cost, we further demonstrate the application of the PCSF as a reusable wristband for smart solar UV radiation monitors. This work provides a way for solar UV radiation monitors that could provide naked-eye monitoring of real-time personal solar UV radiation. [ABSTRACT FROM AUTHOR]

Ag2Te quantum dots (QDs) are important near-infrared (NIR) luminescent materials, which have exhibited great potential for biomedical imaging due to the narrow band gap and low in vivo toxicity. However, it remains a challenge to obtain Ag2Te QDs with uniform size and high photoluminescence quantum yield (PLQY). Herein, a thiolate etching strategy is proposed for the synthesis of high-quality Ag2Te QDs emitting in the second NIR (NIR-II) window. Taking advantage of the activity of a thiol ligand, 1-dodecanethiol, Ag-(I)-thiolate could trigger the association of Ag-(I) with Te on the surface of cubic PbTe QDs and subsequent decomposition of PbTe QDs, resulting in a ripening process for the formation of uniform Ag2Te nanocrystals. The as-prepared Ag2Te exhibited low toxicity and excellent optical properties in the NIR-II window (1300 nm and PLQY = 7%), allowing for the noninvasive in vivo imaging of microvessels (71 μm) with high clarity. This work not only provides a tool for deep tissue fluorescence imaging but also proposes a facile route for the preparation of metal telluride nanocrystals. [ABSTRACT FROM AUTHOR]

A structure-based design of novel memapsin 2 inhibitors that incorporate methylsulfony alanine as the P(sub 2)-ligand and pyrazole and oxazole-derived heterocycles as the P(sub 3)-ligands is reported. This structure-based design led to the development of very potent and highly selective memapsin 2 inhibitors and X-ray structural analysis of protein-inhibitor complexes has uncovered potentially important molecular interactions useful in the design of selectivity against other aspartyl proteases.