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Boel McClure posted an update 5 hours, 4 minutes ago
A water-soluble probe, TPA-1OH, with aggregation-induced emission activity is synthesized and used for expedient real-time fluorescence in situ visualization of latent fingerprints (LFPs). A TPA-1OH aqueous solution exhibits nonfluorescence in pure water while strong fluorescence upon molecular aggregation induced by addition of poor solvent. Fluorescence images of LFPs on a variety of substrates, including rough surfaces such as walls, bricks, and paper, are developed under 405 nm light, by soaking in or spraying with a TPA-1OH aqueous solution (30 μM) without any necessity of organic cosolvents and post-treatment steps. The probe is noncytotoxic at a concentration lower than 50 μM. The development process of LFPs is demonstrated by real-time fluorescence in situ imaging. The exponential relationship between the relative fluorescence intensity and time is deduced from the fitting curve. The LFP images developed by TPA-1OH are evident and intact enough to allow that the level 1-3 details are displayed and analyzed. Noteworthily, the level 3 details of LFPs such as the fingerprint ridge width and the characteristics of the sweat pores are evidently visible under fluorescence microscopy. Even the nanoscopic details exceeding level 3 are visualized under super-resolution microscopy with sub-50 nm optical resolution.Fluoropolymers have found broad applications for many decades. Considerable efforts have focused on expanding access toward main-chain fluorinated polymers. In contrast to previous polymerizations of gaseous fluoroethylenes conducted at elevated temperatures and with high-pressure metallic vessels, we here report the development of a photoorganocatalyzed reversible-deactivation radical alternating copolymerization of chlorotrifluoroethylene (CTFE) and vinyl ethers (VEs) at room temperature and ambient pressure by exposing to LED light irradiation. This method enables the synthesis of various fluorinated alternating copolymers with low Đ and high chain-end fidelity, allowing an iterative switch of the copolymerization between “ON” and “OFF” states, the preparation of fluorinated block alternating copolymers, as well as postsynthetic modifications.The matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI MSI) technique has attracted intense interest in the visualization of drug distribution in tissues. Its capability to spatially resolve individual molecules makes it a unique tool in drug development and research. MEK inhibitor However, low drug content and severe ion suppression in tissues hinder its broader application to resolve drug tissue distribution, especially small molecule drugs with a molecular weight below 500 Da. In this work, an integrated tissue pretreatment protocol was developed to enhance the detection of central nervous system drugs in the mouse brain using MALDI MSI. To evaluate the protocol, brain sections from mice dosed intraperitoneally with donepezil, tacrine, clozapine, haloperidol, and aripiprazole were used. The tissue sections were pretreated serially by washing with ammonium acetate solution, incubation with trifluoroacetic acid vapor, and n-hexane washing before MALDI MSI. Compared with the untreated sample, the signal intensities for the test drugs increased by 4.7- to 31.5-fold after pretreatment. Besides the enhancement of signal intensity, fine optimization of pretreatment time and washing solvents preserved the spatial distribution of target drug molecules. The utility of the developed protocol also provided tissue-specific distribution for five drugs which were well resolved when imaged by MALDI MS.The objective of this study was to evaluate whether whole raw milk originating from Holstein dairy cows affected by lameness alters its composition. A total of 20 healthy control cows and 6 cows diagnosed with lameness were selected out of 100 sampled cows in a nested case control study at 2 weeks postpartum, and whole raw milk samples were collected and analyzed with direct inject/liquid chromatography-tandem mass spectrometry and nuclear magnetic resonance. In total, 168 metabolites were identified and quantified using an in-house mass spectrometry library. A total of 35 of the identified metabolites decreased versus control cows. Only two metabolites (i.e., sn-glycero-3-phosphocholine and phosphatidylethanolamine ae C421) were increased in the milk of lame cows. In conclusion, milk metabotyping of lame cows revealed significant changes in multiple milk components, including amino acids, lipids, and biogenic amines. Most of the milk compounds identified as altered were lowered, suggesting deflection of nutrients from the mammary gland to the host needs for healing lameness-associated pathological processes.In this study, we demonstrate for the first time the fabrication of carboxylated chitosan nanocrystals (ChsNC) with high degree of deacetylation (DDA) at >80% and narrow size distribution. We also studied its application as a sustainable support material for metal-based catalysts. Carboxylated chitin nanocrystals (ChNCs) were initially prepared through partial cleavage of glycosidic bonds in chitin by ammonium persulfate, with concurrent oxidation of chitin C6 primary alcohols to produce carboxylate groups on the surface of the ChNCs. ChsNCs were subsequently prepared using an alkaline deacetylation procedure in the presence of NaBH4 to preserve the nanorod structure of the biomaterial. The resulting nanocrystals feature both carboxyl and amino functional groups. Transmission electron microscopy (TEM), X-ray diffraction (XRD), and Fourier-transform infrared (FTIR) spectroscopy were used to determine the morphology and composition of these carboxylated ChNCs and ChsNCs. Subsequently, we tested the ability of the as-made ChsNCs as a biomass-based catalyst support for Au nanoparticles (NPs) using the 4-nitrophenol reduction and the aldehyde-amine-alkyne (A3) coupling reactions to demonstrate its capabilities in regard to the ones of cellulose nanocrystals (CNCs). In particular, Au NPs over ChsNCs featured the highest turnover frequency (TOF) value for the 4-nitrophenol reduction reported for all Au-based catalysts supported on carbon-based systems. Spectroscopic and imaging techniques confirmed the importance of precisely controlling the redox state of Au as it is being deposited to afford a highly disperse active site on the bionano-support.