Harderhorn2837

The quenching phenomenon of nucleobase-tagged fluorophores on h-BN and Al_hBN sheets was investigated by TD-DFT calculations using the same level of theory. The thymine-tagged fluorophore upon adsorption to the pristine h-BN sheet was found to be blue-shifted (∼43 nm); however, the guanine-tagged fluorophore with Al_hBN showed a remarkable difference from other nucleobase-tagged fluorophores in the absorption and emission spectrum. Guanine-tagged fluorophores showed a smaller blue shift (∼7 nm) in the absorption spectrum; however, it showed a larger red shift (∼55 nm) than the other nucleobase-tagged fluorophores on Al_hBN sheets and can be useful in recognizing a sequence-specific phenomenon as a fluorescent biosensor of DNA and RNA to ascertain the presence of such nucleobases.The real-time, dynamic optical visualization of lesions and margins ensures not only complete resection of the malignant tissues but also better preservation of the vital organs/tissues during surgical procedures. Most imaging probes with an "always-on" signal encounter high background noise due to their non-specific accumulation in normal tissues. By contrast, activatable molecular probes only "turn on" their signals upon reaction with the targeted biomolecules that are overexpressed in malignant cells, offering high target-to-background ratios with high specificity and sensitivity. This review summarizes the recent progress of activatable molecular probes in surgical imaging and diagnosis. The design principle and mechanism of activatable molecular probes are discussed, followed by specific emphasis on applications ranging from fluorescence-guided surgery to endoscopy and tissue biopsy. Finally, potential challenges and perspectives in the field of activatable molecular probe-enabled surgical imaging are discussed.A simple dissolved inorganic carbon (DIC) measurement method featuring self-calibration function via an electrodialytic bicarbonate eluent generator (cEDG) is described. It is based on gas diffusion flow analysis system that uses conductometric detection for sensing the resultant conductivity changes of the effluent caused by CO2 penetration. The standard carbon sources with concentration ranging from 0.1 to 6 mM produced online by cEDG are for DIC calibration, eliminating manual preparation.A simple but efficient fluorogenic probe is reported for accurate imaging of ulcerative colitis via hypoxia detection. The hypoxia produced by ulcerative colitis can lead to the upregulation of nitroreductase (NTR). NB-NO2 provides a unique response to NTR, enabling accurate imaging of Dextran sulphate sodium (DSS)-induced ulcerative colitis in vivo.The FMN riboswitch is a novel drug target for the design of new antibiotics, and efforts have been made to design new charged and uncharged ligands. Uncharged ligands have shown advantages of not requiring any transporter for intracellular transport or proteins for their phosphorylation. 5FDQD (5-(3-(4-fluorophenyl)butyl)-7,8-dimethylpyrido(3,4-b)quinoxaline-1,3(2H,5H)-dione) is a recently reported neutral ligand for the FMN riboswitch active against Clostridium difficile infection in mice. However, the crystal structure of the 5FDQD bound FMN riboswitch is not available, and the mechanism of ligand binding and triggering the function of the riboswitch is not well understood. We have examined 5FDQD for its binding affinity with the FMN riboswitch using the well-tempered metadynamics (WT-MtD) simulation technique. The crystal structure of the FMN riboswitch shows that the FMN interacts with the J4/5 region through the phosphate group with G62; however, the uncharged ligands take advantage of π-π stacking interchieve superior binding affinity with the FMN riboswitch.How solvent motions affect the dynamics of chemical reactions in which the solute undergoes a substantial shape change is a fundamental but elusive issue. This work utilizes reactive simulation and Grote-Hynes theory to explore the effect of solvent motions on the dynamics of the Diels-Alder reaction (in the reverse direction, this reaction involves very substantial solute expansion) in aprotic solvents. The results reveal that the solvent environment is not sufficiently constraining to influence transition state passage dynamics, with the calculated transmission coefficients being close to unity. Even when solvent motions are suppressed or artificially slowed down, the solvent only affects the reaction dynamics in the transition state region to a very small extent. The only notable effect of solvent occurs far from the transition state region and corresponds to caging of the reactants within the reactant well.We trace a polymorphic phase change in solid ammonia films through the emergence of a Frenkel exciton at 194.4 nm, for deposition temperatures of 48 K, 50 K and 52 K. Observations on a timescale of hours give unparalleled access to the individual processes of nucleation and the phase change itself. The excitonic transition is forbidden in the low temperature phase, but greater flexing of the solid state structure in the higher temperature phase makes the transition allowed, as the nano-crystals approach ∼30 unit cells through nucleation. We find activation energies of 21.7 ± 0.6 kJ mol-1 for nucleation and 22.8 ± 0.6 kJ mol-1 for the phase change, corresponding to the breaking of two to three hydrogen bonds.Bacterial infection of wounds delays the healing process, increases the risk of chronic trauma associated with pain and complications, and offers a breeding ground for drug-resistant bacteria. A rapid and effective eradication of the bacterial species in the wound area is thus important. Herein, we designed a phototherapeutic antibacterial platform based on peptides and copper sulfide nanodots (CuS NDs) for multi-mechanistic eradication of bacteria colonized on the wound surface. The antimicrobial peptide weaves into a network in the form of a hydrogel, which supports CuS NDs to generate heat and produce reactive oxygen species (ROS) under the irradiation of near-infrared light (NIR). The heat and ROS generated in situ act as non-contact-based antibacterial factors and together with contact-based antimicrobial peptides cause irreversible membrane destruction, cell content damage, and thermal ablation of the bacteria. Lastly, nanodot-doped peptide hydrogels combined with collagen showed complete bacterial elimination and significantly accelerated wound healing in a splint-fixed mouse infection model.Fluorescent gold nanoclusters are promising nanomaterials for biomedical applications but confronted with low emission efficiency and poor surface functionality. Herein, three kinds of highly luminescent and functionalized gold nanocluster nano-assembled structures were fabricated by poly-l-arginine surface engineering for luminescence improvement. Triparanol purchase The assembly is employed for imaging the glutathione molecule in cells and living organisms with low background and high sensitivity.Protein crystals have attracted a great deal of attention as solid biomaterials because they have porous structures created by regular assemblies of proteins. The lattice structures of protein crystals are controlled by designing molecular interfacial interactions via covalent bonds and non-covalent bonds. Protein crystals have been functionalized as templates to immobilize foreign molecules such as metal nanoparticles, metal complexes, and proteins. These hybrid crystals are used as functional materials for catalytic reactions and structural analysis. Furthermore, in-cell protein crystals have been studied extensively, providing progress in rapid protein crystallization and crystallography. This review highlights recent advances in crystal engineering for protein crystallization and generation of solid functional materials both in vitro and within cells.SnO2 is one of the most promising catalysts for CO2 electroreduction. However, the intrinsic low electrical conductivity and weak CO2 adsorption and activation capability have rendered the reaction kinetically sluggish and inefficient. To surmount these hurdles, herein, W was incorporated into SnO2 nanosheets to modulate the electronic structures. Compared with pristine SnO2, the p-band centre of W-doped SnO2 was elevated towards the Fermi level, accompanied by the reduction in the band gap and work function. As a result, both the CO2 adsorption and the electron transfer process were promoted, thus lowering the activation energy barrier for CO2 reduction. Benefitting from these, a maximum faradaic efficiency of 87.8% was achieved for HCOOH at -0.9 V vs. the RHE. Meanwhile, the current density and energy efficiency approached 20.92 mA cm-2 and 60%, respectively. Such performances could sustain for 14 h without obvious fading and exceeded pristine SnO2 and most reported Sn-based catalysts. Tafel slope and reaction order analyses further suggested that the reaction proceeded following a stepwise electron-proton transfer pathway with the formation of CO2˙- as the rate determining step. This work demonstrated the effectiveness of electronic structure tuning in promoting the catalytic performances of p-block metal oxides and contributed to the development of efficient catalysts for sustainable energy conversion and carbon neutrality.Two dye-loaded metal-organic capsules constructed with different spatial sizes and functional groups simulated the enzymatic substrate activation for hydrogenation of nitroarenes with the kinetics obeying the Michaelis-Menten mechanism.The olivine phosphate LiCoPO4 is a prospective cathode material in high-voltage lithium-ion batteries. During lithium diffusion, the ions must overcome the diffusion energy barrier near the surface and in the bulk. Experimental studies have shown that Fe doping can enhance the electrochemical performance of LiCoPO4 with a doping concentration of x = 0.2 (LiFe0.2Co0.8PO4). DFT calculations can provide detailed understanding of the lithium diffusion mechanism, structural stability, and electronic properties for Fe-doped LiCoPO4 and elucidate the origins for this improvement from a microscopic viewpoint. In this study, the electronic structure of Fe-doped LiCoPO4 was calculated via first principles and compared with that of pristine LiCoPO4. To investigate the surface properties of LiCoPO4, surface energies with low indices were calculated. The results showed that the (010) surface has the lowest surface energy. Minimum energy diffusion pathways and energy barriers were calculated using the NEB method. Our calculations showed that the energy barrier for lithium-ion diffusion can be reduced by Fe doping modification. Furthermore, we investigated the diffusion processes of polarons and lithium ions migrating simultaneously. This study has implications for further application of LiCoPO4 as a cathode material.We recently developed [A. Ferté, et al., J. Phys. Chem. Lett., 2020, 11, 4359] a method to compute single site double core hole (ssDCH or K-2) spectra. We refer to that method as NOTA+CIPSI. In the present paper this method is applied to the O K-2 spectrum of the CO2 molecule, and we use this as an example to discuss in detail its convergence properties. Using this approach, theoretical spectra in excellent agreement with the experimental one are obtained. Thanks to a thorough interpretation of the shake-up states responsible for the main satellite peaks and through comparison with the O K-2 spectrum of CO, we can highlight the clear signature of the two non-equivalent carbon oxygen bonds in the oxygen ssDCH CO2 dication.