Enemarkreed5451

The functionalization of 3-(difluoromethyl)pyridine has been developed via direct deprotonation of -CHF2 with a lithiated base and subsequent trapping with various electrophiles in THF. In situ quenching gives access to 3-pyridyl-CF2-SiMe2Ph as a new silylated compound, which can be postfunctionalized with a fluoride source to obtain a larger library of 3-(difluoroalkyl)pyridines that could not be accessed via direct deprotonation.Linearly conjugated systems have long served as an archetype of conjugated materials, but suffer from two intrinsic structural problems potential instability due to intermolecular interactions and the flexibility of the C-C bonds connecting C═C bonds. Efforts to solve these problems have included the insertion of aromatic units as a part of the conjugation and the introduction of carbon bridges to stop the bond rotation. We report here B/N-doped p-arylenevinylene chromophores synthesized through the incorporation of a cyclopenta[c][1,2]azaborole framework as a part of the conjugated system. The ring strain intrinsic to this new skeleton both flattens and rigidifies the conjugation, and the B--N+ dative bond is much easier to form than a C-C bond, which simplifies the synthetic design. The B-N dative bond also reduces the HOMO-LUMO gap, thereby causing a significant redshift of the absorption and emission compared with their all-carbon congeners while retaining high photostability and high fluorescence quantum yield in both solution and film states. A doubly B/N-doped compound showed emission peaks at 540 nm with a small Stokes shift of 20 nm and a fluorescence quantum yield of 98%. The molecules serve as excellent lipophilic fluorescent dyes for live-cell imaging, showing a higher photostability than that of commercially available BODIPY-based dyes.We report rapid and sensitive phenotyping of bacterial response to antibiotic treatment at single-cell resolution by a Raman-integrated optical mid-infrared photothermal (MIP) microscope. Avexitide chemical structure The MIP microscope successfully detected biochemical changes of bacteria in specific to the acting mechanism of erythromycin with 1 h incubation. Compared to Raman spectroscopy, MIP spectroscopy showed a much larger signal-to-noise ratio at the fingerprint region at an acquisition speed as fast as 1 s per spectrum. The high sensitivity of MIP enabled detection of metabolic changes at antibiotic concentrations below minimum inhibitory concentration (MIC). Meanwhile, the single-cell resolution of the technique allowed observation of heteroresistance within one bacterial population, which is of great clinical relevance. This study showcases characterizing antibiotic response as one of the many possibilities of applying MIP microscopy to single-cell biology.An elevated activity of (bi)carbonate in soils and sediments (pCO2, ∼2%) above current atmospheric CO2 (∼0.04%) could influence the iron cycling in mineral-water interfacial chemistry. However, the impact of (bi)carbonate on mineral transformation is unclear. Here, a model short range-ordered iron oxyhydroxide, two-line ferrihydrite, was used to evaluate the impact of (bi)carbonate on mineral transformation at near-neutral pH using experimental geochemistry, X-ray diffraction, X-ray absorption spectroscopy, transmission electron microscopy, and Fourier transform infrared spectroscopy. Results showed that (bi)carbonate promoted the transformation of ferrihydrite to hematite and retarded the goethite formation. As pCO2 increased from 408 to 20,000 ppmv at 40 °C, the transformation efficiency of ferrihydrite increased from 53 to 95%, and the formation of hematite increased from 13 to 76%. During the formation of hematite, a terminal ligand on a Fe(III)O6 octahedral monomer such as a hydroxyl or water was displaced to form Fe(III)O6 octahedral dimers and/or polymers. Because the Fe-O bond of ≡(Fe-O)2-CO is much weaker than that of ≡Fe-O-H, the -O2CO group can be more easily replaced by two terminal -OH groups; the dehydration/rearrangement between Fe(III)O6 octahedral monomers was enhanced under high pCO2. Results suggest that high carbonate activity is an important geochemical parameter controlling the occurrence of hematite in oxic environments and, in turn, iron cycling in the critical zone.Biomarker-activatable theranostic formulations offer the potential for removing specific tumors with a high diagnostic accuracy and a significant pharmacological effect. Herein, we developed a novel activatable theranostic nanoformulation UAS-PD [upconversion nanophosphor (UCNP)-aptamer/ssDNA-pyropheophorbide-a (PPA)-doxyrubicin (DOX)], which can recognize specific cancer cells with sensitivity and trigger the localized photodynamic destruction and enhanced chemotherapy. UAS-PD was constructed by the conjugation of UCNPs and aptamer probes containing the photosensitizer PPA and the chemotherapeutic drug DOX. When cancer cells are present, the UAS-PD specifically binds to PTK7, an overexpressed protein present on the surface of cancer cells, through conformational recombination of the aptamer structure and switches its upconversion luminescence from 655 to 540 nm. This long-lived ratiometric optical signal provides an ultrasensitive detection limit as low as 3.9 nM for PTK7. Changes in the conformation of UAS-PD can also induce PPA to approach UCNPs, which can produce cytotoxic singlet oxygens under near-infrared excitation to destroy the cell membrane and enhance its permeability for the simultaneously released DOX that targets cellular DNA degradation, which results in a highly effective tumor-killing effect by synergistic extra-intracellular sequential damage.The twin, chemically orthogonal protein ligation domains, SpyCatcher and SnoopCatcher, were used to link two engineered proteins into poly(ethylene glycol) (PEG) hydrogels in order to control both endothelial cell adhesion and material-mediated pro-mitotic stimulation. SpyCatcher was appended with an N-terminal adhesion ligand RGDS to form RGDS-SC, and SnoopCatcher was appended with the vascular endothelial growth factor (VEGF)-mimetic peptide QK to form QK-SnpC. QK-SnpC formed a spontaneous covalent bond with SnoopTag peptide with 40% reaction efficiency, both in solution, in a PEG gel containing SnoopTag peptide, and in a PEG gel with both SnoopTag and SpyTag sites. QK-SnpC added to cell culture media enhanced endothelial cell proliferation compared to a negative control, and was statistically indistinguishable from the positive control of 130 pM VEGF165. Endothelial cells seeded onto PEG gels presenting both RGDS-SC and QK-SnpC showed ∼50% of cells actively proliferating (defined as Ki67+), compared to ∼31% of cells seeded on gels presenting RGDS-SC alone.