Sanfordbarbee4373

The citrate-based tissue adhesive, synthesized by citric acid, diol, and dopamine, is a kind of mussel-inspired adhesive. The adhesion of mussel-inspired adhesive is not completely dependent on 3, 4-dihydroxyphenylalanine (Dopa) groups. The backbone structure of the adhesive also greatly affects the adhesion. In this study, to explore the effects of hydrophobicity and hydrophilicity of the backbone structure on adhesion, we prepared a series of citrate-based tissue adhesives (POEC-d) by changing the molar ratio of two diols, 1, 8-octanediol (O) and poly(ethylene oxide) (E), which formed hydrophobic segment units and hydrophilic segment units, respectively, in the molecule structure. The properties of cured adhesives showed that the adhesive with high E units had high swelling, rapid degradation, and low cohesion. In the adhesion strength measurement on the porcine skin, the adhesive with higher hydrophobicity was more likely to perform better. For the interfacial adhesion, hydrophilicity was conducive to the diffusion and penetration on the skin surface, but hydrophobic interaction showed a stronger effect to adhere with skin and hydrophobic association increased the adhesive concentration on the interface; for the bulk cohesion, hydrophobicity led to coacervation, promoting the Dopa-quinone coupling for cross-linking. In this amphipathic, citrate-based, soft-tissue adhesive system, when the feed ratio of hydrophilic segment was lower than 0.7, the coacervation could be formed through hydrophobic interaction, forming an efficient underwater adhesion system similar to that of mussels.A novel strategy for the synthesis of (E)-3-((arylsulfonyl)methyl)-4-substituted benzylidenechromene derivatives via a metal-free radical annulation reaction of oxygen-containing 1,7-enynes with thiosulfonates has been developed. The reaction shows broad substrate scope, wide functional group tolerance, and moderate to excellent yields. Moreover, thiosulfonates were well driven to achieve the bifunctionalization reaction of oxo-1,7-enynes which derived from aliphatic alkynes. In addition, the (E)-configuration of the products was highly controlled by the structure of 1,7-enyne.Asymmetric hydrogenation of conjugated enones is one of the most efficient and straightforward methods to prepare optically active ketones. In this study, chiral bidentate Ir-N,P complexes were utilized to access these scaffolds for ketones bearing the stereogenic center at both the α- and β-positions. Excellent enantiomeric excesses, of up to 99%, were obtained, accompanied with good to high isolated yields. Challenging dialkyl substituted substrates, which are difficult to hydrogenate with satisfactory chiral induction, were hydrogenated in a highly enantioselective fashion.The field of micromotors has been growing exponentially with increased emphasis on biomedical applications, with various in vivo demonstrations of targeted drug delivery, biosensing, and gene delivery, among others. In parallel, these micromotors have been recently used for probing the rheological properties of both intra- and extracellular environments. Here, we demonstrate the application of magnetic micromotors for investigation of rheological properties of human blood. While there are several techniques to sense mechanical properties of blood, such as deformability of the red blood cells, this is the first experimental observation of using micromotors for these biophysical investigations. We hope that this will lead to a better understanding of the nature of interactions of micromotors with biological systems and expand the scope of micromotors for probing other related systems, such as interstitial fluids and other complex biological fluids.We previously described BCLConf, a knowledge-based conformation sampling algorithm utilizing a small molecule fragment rotamer library derived from the Cambridge Structural Database (CSD, license required), as a component of the BioChemical Library (BCL) cheminformatics toolkit. This paper describes substantial improvements made to the BCLConf algorithm and a transition to a rotamer library derived from molecules in the Crystallography Open Database (COD, no license required). We demonstrate the performance of the new BCLConf on native conformer recovery in the Platinum dataset of high-quality protein-ligand complexes. This set of 2859 structures has previously been used to assess the performance of over a dozen conformer generation algorithms, including the Conformator, Balloon, RDKit DG, ETKDG, Confab, Frog2, MultiConf-DOCK, CSD conformer generator, ConfGenX-OPSL3 force field, Omega, excalc, iCon, and MOE. These benchmarks suggest that the CSD conformer generator is at the state of the art of reported conformer generators. Our results indicate that the improved BCLConf significantly outperforms the CSD conformer generation algorithm at binding conformer recovery across a range of ensemble sizes and with similarly fast rates of conformer generation. BCLConf is now distributed with the COD-derived rotamer library and is free for academic use. selleck chemicals The BCL can be downloaded at http//meilerlab.org/bclcommons for Windows, Linux, or Apple operating systems. BCLConf can now also be accessed via webserver at http//meilerlab.org/bclconf.UV-vis absorption and magnetic circular dichroism (MCD) spectra of octakis thioethyl "free base" porphyrazine H2OESPz and its metal complexes MOESPz (M = Mg, Zn, Ni, Pd, Cu), as well as of [MnOESPz(SH)] were recorded. In the last case, MCD proved to have quite good sensitivity to the coordination of this complex with 1-methylimidazole (1-mim) in benzene. Time-dependent density functional theory (TDDFT) calculations were carried out for the considered porphyrazine complexes and showed good performance on comparing with MCD and UV-vis experimental spectra, even in the open-shell Cu and Mn cases. Calculations accounted for the red shift observed in the thioalkyl compounds and allowed us to reveal the role of sulfur atoms in spectroscopically relevant molecular orbitals and to highlight the importance of the conformations of the thioethyl external groups. Calculated MCD spectra of [MnOESPz(SH)] confirm the Mn(III) → Mn(II) redox process, which leads to the [Mn(OESPz)(1-mim)2] species, and the relevance of the spin state for MCD is revealed.Stimulating tunable room-temperature phosphorescence (RTP) is still a challenge in photochromic systems, which is vital for multifunctional coordination materials. Herein, we synthesized two new photochromic chain complexes through self-assembly of the nonphotochromic 1,3,5-tris(4-pyridyl)benzene ligand, diphosphonate, and Ln(III) ions (1 for Ln(III) = Dy and 2 for Ln(III) = Gd). Both compounds showed fast photoresponses with the color turning from yellow to dark gray with a reversible decoloration by heating or storage in the dark. The electron transfer photochromic behavior with the generated stable radicals was further confirmed by the room-temperature UV-vis and electron paramagnetic resonance spectra. Furthermore, via tuning the generation and disappearance of stable radicals, reversible room-temperature fluorescence and phosphorescence for both compounds were switched by light irradiation and a thermal treatment, with an enhanced intensity for RTP and a decrease in fluorescence during the duration of Xe-lamp light irradiation. This work provides a new strategy that photogenerated radicals could promote and enhance RTP properties in functional materials.To meet various requirements for electron transfer (ET) at the substrate/electrolyte interface, mixed redox couples assigned to different functions have been applied. While in all studies the mixed redox species had different redox potentials, such redox systems inherently lose energy by ET between the species. We report interfacial ET kinetics employing mixed-ligand electrolytes based on Co2+/3+ complexes with mixtures of dimethyl- and dinonyl-substituted bipyridyl (bpy) ligands with the same redox potential. The ET rates of the mixed electrolytes decrease with the increasing ratio of the dinonyl-bpy ligand, with substrates adsorbed by molecules without alkyl chains due to a blocking effect. However, when the molecules on substrates have four alkyl chains, the ET rate between the molecules and the electrolytes with increasing ratio of the dinonyl-bpy ligand is enhanced. The substrate-dependent behavior is explained by selective intermolecular interactions. link2 The results open design flexibility for mixed-redox electrolyte systems to control ET at multi-substrate interfaces and provide a novel means to tune ET rates simultaneously for various ET processes in a system without losing energy by the ET.A redox neutral Co(III)-catalyzed annulation of α,β-unsaturated oxime ether with alkyne has been reported. Multisubstituted pyridines were synthesized in good yields without the use of any heavy metal oxidants. The developed methodology tolerates a variety of functional groups. Notably, this transformation has been applied to the late-stage modification of the bioactive molecule dehydropregnenolone.Reduced-scaling methods are needed to make accurate and systematically improvable coupled cluster linear response methods for the calculation of molecular properties tractable for large molecules. In this paper, we examine the perturbed pair natural orbital-based PNO++ approach that creates an orbital space optimized for response properties derived from a lower-cost field-perturbed density matrix. We analyze truncation errors in correlation energies, dynamic polarizabilities, and specific rotations from a coupled cluster singles and doubles (CCSD) reference. We find that incorporating a fixed number of orbitals from the pair natural orbital (PNO) space into the PNO++ method-a new method presented here, the "combined PNO++" approach-recovers accuracy in the CCSD correlation energy while preserving the well-behaved convergence behavior of the PNO++ method for linear response properties.Membranes are ubiquitous structures in cells. The effects of membranes on various functional molecules have been reported, but their behaviors under macromolecular crowding and cell-sized confinement have not fully been understood. In this study, we model an intracellular environment by crowding micrometer-sized droplets and investigate the effects of membrane properties on molecular diffusion. The molecular diffusion inside small droplets covered with a lipid layer of phosphatidylcholine (PC) becomes slower compared with that of the corresponding bulk solutions under a crowding condition of polysaccharide dextran but not of its monomer unit, glucose. The addition of a poly(ethylene glycol) conjugated lipid (PEGylated lipid) to the PC membrane significantly alters the degree of slow diffusion observed inside small droplets of concentrated dextran. link3 Interestingly, the change is not monotonic against dextran concentration; that is, the PEGylated membrane increases and decreases the degree of slow diffusion with increasing dextran concentration. We explain the nonmonotonic alternation from the increase in effective dextran concentration and the hindered temporal adsorption of dextran to the membrane. Because diffusion alteration by adding PEGylated lipid is observed for condensed small droplets of linear polymer PEG and hydrophilic protein bovine serum albumin, the phenomenon is general for other polymer systems as well. Furthermore, our findings may facilitate the understanding of intracellular molecular behaviors based on membrane effects as well as the development of numerous applications using polymer droplets.