Red Emitting Solid-State CDs/PVP with Hydrophobicity for Latent Fingerprint Detection.

Fluorescent carbon dots (CDs) are a new type of photoluminescent nanomaterial. Solid-state CDs usually undergo fluorescence quenching due to direct π-π* interactions and superabundant energy resonance transfer. Therefore, the preparation of solid-state fluorescent CDs is a challenge, especially the preparation of long wavelength solid-state CDs. In this research, long wavelength emission CDs were successfully synthesized by solvothermal methods, and the prepared CDs showed good hydrophobicity. The composite solid-state CDs/PVP (Polyvinyl pyrrolidone) can emit strong red fluorescence, and the quantum yield (QY) of the CDs/PVP powder reaches 18.9%. The prepared CDs/PVP solid-state powder was successfully applied to latent fingerprint detection. The results indicate that the latent fingerprints developed by CDs/PVP powder have a fine definition and high contrast visualization effect, which proves that the prepared CDs/PVP has great application potential in latent fingerprint detection. This study may provide inspiration and ideas for the design of new hydrophobic CDs.

Carbon monoxide impurities in hydrogen detected with resonant photoacoustic cell using a mid-IR laser source.

We report on a photoacoustic sensor system based on a differential photoacoustic cell to detect the concentration of CO impurities in hydrogen. A DFB-QCL laser with a central wavelength of 4.61 µm was employed as an exciting source with an optical power of 21 mW. Different concentrations of CO gas mixed with pure hydrogen were injected into the photoacoustic cell to test the linear response of the photoacoustic signal to the CO concentration. The stability of the long-term operation was verified by Allan-Werle deviation analysis. The minimum detection limit (MDL, SNR=1) results 8 ppb at 1 s and reaches a sub-ppb level at 100 s of integration time. Dynamic response of the system is linear and has been tested up to the concentration of 6 ppm. Saturation conditions are expected to be reached for CO concentration larger than 100 ppm.

Toluene induces hormetic response of soil alkaline phosphatase and the potential enzyme kinetic mechanism.

Hormesis of soil enzyme that involved in heavy metal has been attracting much more attention for risk assessment of heavy metal toxicity, but insufficient studies were conducted to define the hormetic responses induced by toluene or other organic pollutions. The objectives of this study were to investigate the hormetic responses of soil enzyme induced by toluene and explore the potential enzyme kinetic mechanism. Soil alkaline phosphatase (ALP) activity was regarded as the endpoint to explore the hormetic responses under different doses of toluene (0.0, 0.1, 0.5, 1.0, 2.0, 3.0, 5.0, 10.0, 50.0 and 100.0 µL g-1). Subsequently, we conducted the experiments of enzymatic reaction kinetics and pure enzyme to further verify the potential mechanisms of soil ALP's hormesis. Results showed that ALP activities at 0.1-1.0 µL g-1 toluene were significantly increased in contrast to the control (0 µL g-1 toluene) (P < 0.05) at the exposure time of 30, 36, 48 and 54 h, with the maximum stimulation magnitudes of 24-43%. ALP activities were almost not affected by toluene (2-100 µL L-1) in the whole experimental period (6-54 h). Meanwhile, the values of catalytic efficiency (the radio Vmax/Km, Vmax: maximum reaction velocity and Km: Michaelis constant) and Vmax significantly increased compared with the control, but the value of Km decreased from 2.5 to 1.6. Overall, low dose toluene can induce hormesis of soil ALP. The potential reason is that low-dose toluene could enhance the combination of soil ALP and substrates. We believe that this study will provide a new viewpoint for ecological risk assessment of toluene contaminated soils.

Recent developments of small molecule EGFR inhibitors based on the quinazoline core scaffolds.

Progress in identifying and understanding the molecular and cellular causes of cancer has led to the discovery of anomalies that characterize cancer cells and that represent targets for the development of cancer therapeutics. One such target is the epidermal growth factor receptor (EGFR), a transmembrane protein that is frequently dysregulated in cancer cells and associated with the development, progression and aggressiveness of a number of malignancies. Inhibition of EGFR signaling has thus been identified as an attractive strategy in control of tumor proliferation, and over a decade of intense activity in the field has culminated in the discoveries and subsequent approvals of gefitinib and erlotinib for the treatment of non-small cell lung cancer. However, the drug's resistance to gefitinib and erlotinib has been clinically observed. Therefore, intensive efforts have been made in the discovery of novel potent and selective EGFR inhibitors. This review will focus on the developments of small molecule EGFR inhibitors based on the quinazoline core scaffolds in recent 5 years. Diverse EGFR inhibitors are classified as 4-anilinoquinazolines and 4-nonanilininoquinazolines, their biological data are described, and the structure-activity relationships (SARs) are discussed.