Real-time tracking and in vivo visualization of β-galactosidase activity in colorectal tumor with a ratiometric near-infrared fluorescent probe

Development of “smart” noninvasive bioimaging probes for trapping specific enzyme activities is highly desirable for cancer therapy in vivo. Given that β-galactosidase (β-gal) is an important biomarker for cell senescence and primary ovarian cancers, we design an enzyme-activatable ratiometric near-infrared (NIR) probe (DCM-βgal) for the real-time fluorescent quantification and trapping of β-gal activity in vivo and in situ. DCM-βgal manifests significantly ratiometric and turn-on NIR fluorescent signals simultaneously in response to β-gal concentration, which makes it favorable for monitoring dynamic β-gal activity in vivo with self-calibration in fluorescent mode. We exemplify DCM-βgal for the ratiometric tracking of endogenously overexpressed β-gal distribution in living 293T cells via the <i>lacZ</i> gene transfection method and OVCAR-3 cells, and further realize real-time in vivo bioimaging of β-gal activity in colorectal tumor-bearing nude mice. Advantages of our system include light-up ratiometric NIR fluorescence with large Stokes shift, high photostability, and pH independency under the physiological range, allowing for the in vivo real-time evaluation of β-gal activity at the tumor site with high-resolution three-dimensional bioimaging for the first time. Our work provides a potential tool for in vivo real-time tracking enzyme activity in preclinical applications

Semi-Supervised Deep Learning Representations in Earth Observation Based Forest Management

In this study, we examine the potential of several self-supervised deep learning models in predicting forest attributes and detecting forest changes using ESA Sentinel-1 and Sentinel-2 images. The performance of the proposed deep learning models is compared to established conventional machine learning approaches. Studied use-cases include mapping of forest disturbance (windthrown forests, snowload damages) using deep change vector analysis, forest height mapping using UNet+ based models, Momentum contrast and regression modeling. Study areas were represented by several boreal forest sites in Finland. Our results indicate that developed methods allow to achieve superior classification and prediction accuracies compared to traditional methodologies and mimimize the amount of necessary in-situ forestry data

<p>Enhancing dimethyldichlorosilane production in Rochow-Muller reaction by adding ZnO-Sn-P co-promoter in CuO/SiO2</p>

Commercial nonsupported Cu-based catalysts have to be mixed with various promoters to enhance their catalytic performance in the Rochow-Muller reaction. However, considerable debates still exist at a fundamental level on how these promoters function. Herein, we systematically investigated the effects of ZnO, Sn, and P promoters on the catalytic property of the CuO/SiO2 catalyst for synthesizing dimethyldichlorosilane (M2) via the Rochow-Muller reaction. A series of CuO/SiO2 catalysts containing these promoters were prepared by the ball-milling method. The CuO/SiO2 catalyst with the coexistence of ZnO, P, and Sn promoters showed the highest catalytic activity, even superior to the commercial non supported Cu-based catalysts. Detailed characterizations showed the increased capability for oxygen adsorption on the CuO surface and dissociative chemisorption of methyl chloride led to the improved catalytic performance. This work deciphers the promoter mechanism and demonstrates a promising strategy for the efficient synthesis of M2.(C) 2022 Elsevier Inc. All rights reserved

<p>Enhancing dimethyldichlorosilane production in Rochow-Muller reaction by adding ZnO-Sn-P co-promoter in CuO/SiO2</p>

Commercial nonsupported Cu-based catalysts have to be mixed with various promoters to enhance their catalytic performance in the Rochow-Muller reaction. However, considerable debates still exist at a fundamental level on how these promoters function. Herein, we systematically investigated the effects of ZnO, Sn, and P promoters on the catalytic property of the CuO/SiO2 catalyst for synthesizing dimethyldichlorosilane (M2) via the Rochow-Muller reaction. A series of CuO/SiO2 catalysts containing these promoters were prepared by the ball-milling method. The CuO/SiO2 catalyst with the coexistence of ZnO, P, and Sn promoters showed the highest catalytic activity, even superior to the commercial non supported Cu-based catalysts. Detailed characterizations showed the increased capability for oxygen adsorption on the CuO surface and dissociative chemisorption of methyl chloride led to the improved catalytic performance. This work deciphers the promoter mechanism and demonstrates a promising strategy for the efficient synthesis of M2.(C) 2022 Elsevier Inc. All rights reserved

Meteorological conditions and structures of atmospheric boundary layer in October 2004 over Pearl River Delta area

High-level concentrations of air pollutants usually occur in autumn and winter over Peal River Delta (PRD), China. Atmospheric boundary layer observations were carried out at Qingyuan, Panyu and Xinken in PRD in October 2004. Wind speed, wind direction, air temperature and aerosol characteristics were measured by radio soundings and Raman LIDAR. The observational results showed that surface high-pressure system (anti-cyclone), descent motion outside of hurricane and sea breeze would result in the high-level concentrations. The averaged height of atmospheric boundary layer in nighttime was about 200 m, while in day time the maximal value was about 1200 m. The aerosol layer typically reached up to 1.5-3.0 km. The averaged aerosol optical depth was 0.91 at 532 nm wavelength and aerosol mainly originated from fossil fuel and biomass-burning emissions. The presence of anti-cyclone high-pressure systems and sea breeze lead to the formation of three inversion layers and two aerosol layers as well as quite specific vertical profiles of the wind velocity over Xinken station.Peer reviewe

GSH-Activated NIR Fluorescent Prodrug for Podophyllotoxin Delivery

Theranostic prodrug therapy enables the targeted delivery of anticancer drugs with minimized adverse effects and real-time <i>in situ</i> monitoring of activation of the prodrugs. In this work, we report the synthesis and biological assessment of the near-infrared (NIR) prodrug DCM-S-PPT and its amphiphilic copolymer (<i>m</i>PEG-DSPE)-encapsulated nanoparticles. DCM-S-PPT is composed of podophyllotoxin (PPT) as the anticancer moiety and a dicyanomethylene-4<i>H</i>-pyran (DCM) derivative as the NIR fluorescent reporter, which are linked by a thiol-specific cleavable disulfide bond. <i>In vitro</i> experiments indicated that DCM-S-PPT has low cytotoxicity and that glutathione (GSH) can activate DCM-S-PPT resulting in PPT release and a concomitant significant enhancement in NIR fluorescence at 665 nm. After being intravenously injected into tumor-bearing nude mice, DCM-S-PPT exhibited excellent tumor-activated performance. Furthermore, we have demonstrated that <i>m</i>PEG-DSPE as a nanocarrier loaded with DCM-S-PPT (<i>m</i>PEG-DSPE/DCM-S-PPT) showed even greater tumor-targeting performance than DCM-S-PPT on account of the enhanced permeability and retention effect. Its tumor-targeting ability and specific drug release in tumors make DCM-S-PPT a promising prodrug that could provide a significant strategy for theranostic drug delivery systems

Combined effect of boundary layer recirculation factor and stable energy on local air quality in the Pearl River Delta over southern China

<p>Atmospheric boundary layer (ABL) has a significant impact on the spatial and temporal distribution of air pollutants. In order to gain a better understanding of how ABL affects the variation of air pollutants, atmospheric boundary layer observations were performed at Sanshui in the Pearl River Delta (PRD) region over southern China during the winter of 2013. Two types of typical ABL status that could lead to air pollution were analyzed comparatively: weak vertical diffusion ability type (WVDAT) and weak horizontal transportation ability type (WHTAT). Results show that (1) WVDAT was featured by moderate wind speed, consistent wind direction, and thick inversion layer at 600~1000 m above ground level (AGL), and air pollutants were restricted in the low altitudes due to the stable atmospheric structure; (2) WHTAT was characterized by calm wind, varied wind direction, and shallow intense ground inversion layer, and air pollutants accumulated in locally because of strong recirculation in the low ABL; (3) recirculation factor (RF) and stable energy (SE) were proved to be good indicators for horizontal transportation ability and vertical diffusion ability of the atmosphere, respectively. Combined utilization of RF and SE can be very helpful in the evaluation of air pollution potential of the ABL.</p> <p><i>Implications</i>: Air quality data from ground and meteorological data collected from radio sounding in Sanshui in the Pearl River Delta showed that local air quality was poor when wind reversal was pronounced or temperature stratification state was stable. The combination of horizontal and vertical transportation ability of the local atmosphere should be taken into consideration when evaluating local environmental bearing capacity for air pollution.</p

Ni-Ni3P/SiO2 Catalyst for Highly Selective Production of Silicon Tetrachloride via Silicon Hydrochlorination

: SiHCl3 (TCS) and SiCl4 (STC), important chlorosilanes in the silicon industry, are currently produced by noncatalytic silicon hydrochlorination with a selectivity of 85% for TCS and 15% for STC approximately. It is a significant challenge to selectively produce TCS and STC with the desired ratio in one reactor to realize flexible manufacturing that meets the periodic market demands. In the present work, we develop a novel Ni-Ni3P/ SiO2 catalyst using a simple reduction synthesis method to produce STC selectively in Si hydrochlorination. The catalyst performance is evaluated under different industrial operating conditions. It shows that the Ni-Ni3P/SiO2 catalyst exhibits a selectivity higher than 90% for STC and a selectivity of <10% for TCS under the optimal conditions. The calculations based on the density functional theory show that P-modified Ni-based catalysts promote the breakage of HCl bonds and make the product favor STC instead of TCS. Therefore, it is possible to realize flexible manufacture of TCS and STC in one reactor by combining the CuO-based catalysts reported in our previous work to enhance TCS production and the Ni-Ni3P/SiO2 catalyst developed in this work to promote STC production

Structurally Rigid 9‑Amino-benzo[<i>c</i>]cinnoliniums Make Up a Class of Compact and Large Stokes-Shift Fluorescent Dyes for Cell-Based Imaging Applications

Classic fluorescent dyes, such as coumarin, naphthalimide, fluorescein, BODIPY, rhodamine, and cyanines, are cornerstones of various spectroscopic and microscopic methods, which hold a prominent position in biological studies. We recently found that 9-amino-benzo­[<i>c</i>]­cinnoliniums make up a novel group of fluorophores that can be used in biological studies. They are featured with a succinct conjugative push–pull backbone, a broad absorption band, and a large Stokes shift. They are potentially useful as a small-molecule alternative to R-phycoerythrin to pair with fluorescein in multiplexing applications