Bruhnjefferson4053

Health benefits have been associated with the consumption of omega-3 polyunsaturated fatty acids (PUFA). Linseed oil is rich in long chain omega-3 PUFA, but can generate toxic compounds due to its high susceptibility to oxidation. The nature of the emulsifier can affect both lipolysis and oxidation during digestion since these phenomena occur at the oil-water interface. The objective of this study was to compare the effect of low-molecular weight surfactants (cetyltrimethylammonium bromide (CTAB), Citrem), protein (sodium caseinate, fish gelatin) and polysaccharides (gum arabic, modified starch) on the structure of linseed oil emulsions, lipolysis and formation of reactive oxidation species during in vitro digestion. The emulsion stabilized with Citrem underwent extensive coalescence in the gastric phase, which strongly decreased the extent of lipid digestion and reduced the formation of oxidation markers relative to other emulsions. Emulsions stabilized by proteins and modified starch showed aggregation with partial coalescence in the gastric phase, but protein-stabilized emulsions showed better resistance to oxidation. This study shows that emulsifier properties affect the susceptibility of the emulsion to aggregation and coalescence in the gastrointestinal environment, and strongly influence the extent of lipid digestion and the formation of reactive oxidation products. These findings point out the importance of the choice of the emulsifier to control the lipid digestibility and the protection of sensible lipids thus promoting optimal nutritional properties in omega-3-enriched foods.Trodusquemine is an aminosterol known to prevent the binding of misfolded protein oligomers to cell membranes and to reduce their toxicity in a wide range of neurodegenerative diseases. Its precise mechanism of action, however, remains unclear. To investigate this mechanism, we performed confocal microscopy, fluorescence resonance energy transfer (FRET) and nuclear magnetic resonance (NMR) measurements, which revealed a strong binding of trodusquemine to large unilamellar vesicles (LUVs) and neuroblastoma cell membranes. Then, by combining quartz crystal microbalance (QCM), fluorescence quenching and anisotropy, and molecular dynamics (MD) simulations, we found that trodusquemine localises within, and penetrates, the polar region of lipid bilayer. This binding behaviour causes a decrease of the negative charge of the bilayer, as observed through ζ potential measurements, an increment in the mechanical resistance of the bilayer, as revealed by measurements of the breakthrough force applied with AFM and ζ potential measurements at high temperature, and a rearrangement of the spatial distances between ganglioside and cholesterol molecules in the LUVs, as determined by FRET measurements. These physicochemical changes are all known to impair the interaction of misfolded oligomers with cell membranes, protecting them from their toxicity. Taken together, our results illustrate how the incorporation in cell membranes of sterol molecules modified by the addition of polyamine tails leads to the modulation of physicochemical properties of the cell membranes themselves, making them more resistant to protein aggregates associated with neurodegeneration. More generally, they suggest that therapeutic strategies can be developed to reinforce cell membranes against protein misfolded assemblies.DNAzymes were previously identified by in vitro selection for a variety of chemical reactions, including several biologically relevant peptide modifications. However, finding DNAzymes for peptide lysine acylation is a substantial challenge. By using suitably reactive aryl ester acyl donors as the electrophiles, here we used in vitro selection to identify DNAzymes that acylate amines, including lysine side chains of DNA-anchored peptides. Some of the DNAzymes can transfer a small glutaryl group to an amino group. These results expand the scope of DNAzyme catalysis and suggest the future broader applicability of DNAzymes for sequence-selective lysine acylation of peptide and protein substrates.To investigate the effects of chirality on the phase behavior of ionic plastic crystals and ionic liquids, salts of a chiral sandwich complex with various anions were synthesized. The synthesized salts have the general chemical formula [Ru(C5H5)(C6H5CHCH3OCH3)]X (X = CB11H12, CF3BF3, PF6, CPFSA (= [double bond, length as m-dash]CF2(SO2CF2)2N)), where the ruthenium complex possesses a chiral substituent. The racemates of the salts with the CB11H12, CF3BF3, and PF6 anions crystallized as a solid solution, racemic compound, and conglomerate, respectively. The (S)-enantiomer and the racemate of the CB11H12 salt exhibited phase transitions to the ionic plastic phase and melted at high temperatures. Further, this salt exhibited polymorphism, as crystallographically investigated. Most of the other salts were ionic liquids exhibiting no plastic phase. The CPFSA salt was liquid and exhibited glass transition at low temperatures.Ultrafast intersystem crossing (ISC) in transition metal complexes leads to a long-lived active state with a high yield, which leads to efficient light energy conversion. The detailed mechanism of ISC may lead to a rational molecular design of superior transition metal complexes. Coherent nuclear wave packets observed in femtosecond time-resolved spectroscopies provide important information on the excited-state dynamics. In particular, analyzing the nuclear wave packets in both the reactant and the product may unveil the molecular dynamics of an ultrafast reaction. In this study, experimental evidence proving the reaction coordinates of the ultrafast ISC of ruthenium(ii) complexes is presented using coherent vibrational spectroscopy with a quantum chemical simulation of coherent vibrational motion. We observed vibrational modes strongly coupled to the ISC, whose vibrational coherences undergo remarkable attenuation after the ISC. The coupled modes contain metal-ligand stretching or symmetry breaking components, and the faster ISC rates of lower-symmetry ruthenium(ii) complexes support the significance of the latter.The physical properties of membranes of hybrid polymer lipid vesicles are so far relatively unknown. Since their discovery a decade ago, many studies have aimed to show their great potential in many fields of application, but so far, few systematic studies have been carried out to decipher the relationship between the molecular characteristics of the components (molar mass, chemical nature, and architecture of the copolymer), the membrane structure and its properties. In this work, we study the association of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) and poly(dimethylsiloxane)-b-poly(ethylene oxide) (PDMS-b-PEO) diblock copolymers of different molar masses in giant hybrid vesicles and establish a complete phase diagram of the membrane structure. We also measured the mechanical properties of the giant hybrid unilamellar vesicle (GHUV) through micropipette aspiration at different lipid/polymer compositions. Thanks to a previous work using triblock PEO-b-PDMS-b-PEO copolymers, we were able to reveal the effect of the architecture of the block copolymer on membrane structure and properties. Besides, the association of diblock copolymers PDMS-b-PEO and POPC leads to the formation of hybrid vesicles with unprecedented membrane toughness.We develop an optical image tracking technique for the simultaneous observation of a wide area in proximity to the electrode, and study the growth of bubbles during hydrogen gas evolution in alkaline water electrolysis. Using a diffusion model we can successfully extract the concentration profile of dissolved hydrogen gas as a function of distance from the electrode. The obtained concentrations agree well with the values by the electrochemical method.The cross-dehydrogenative arylation of benzylic C-H bonds with arenes provides straightforward access to synthetically useful 1,1-diarylmethanes, from readily available starting materials. Current approaches suffer from limited substrate scope, requirement for large excesses of alkyl arene and/or non-trivial reaction set up. We report a transition metal-free cross-dehydrogenative arylation of benzylic C-H bonds using alkyl benzene derivatives and electron-rich arenes as coupling partners. The method proceeds through the in situ generation of a reactive benzyl fluoride intermediate which then reacts with the nucleophilic arene. The reaction tolerates a wide variety of functional groups including unprotected polar functionality and has been applied to the late-stage benzylation of several biologically relevant molecules.The efficiency of the fluorescence sensitivity of a sensor may be tuned by the modulation of the steric and electronic parameters in the structure. In this study, the thiophenyl Schiff base (E)-N1-(phenyl(pyridin-2-yl)methyl)-N2-(thiophen-2-ylmethylene)benzene-1,2-diamine (HL') exhibited very high selectivity and a sensitive fluorescence enhancement towards Fe3+ with violet emission (λem, 385 nm; LOD, 3.8 nM). On the other hand, the naphthyl Schiff base (E)-1-(((2-((phenyl(pyridin-2-yl)methyl)amino)phenyl)imino)methyl)naphthalen-2-ol (H2L) exhibited fluorescence sensitivity towards Al3+, showing blue emission (λem, 502 nm; LOD, 3.3 nM) in H2O (HEPES buffer, pH 7.4) medium. The emission enhancement of HL' upon binding to Fe3+ may be considered to be due to the restriction of intramolecular rotation, while the selectivity of H2L towards Al3+ may be due to the turn on emission through the restriction of excited state intramolecular proton transfer (ESIPT) and the introduction of chelation enhanced fluorescence (CHEF). Furthermore, DFT computation supported the sensing strategy and the probes were applied for intracellular detection of Fe3+ and Al3+ in HepG2 cell lines.The all-vanadium redox flow battery is considered to be a dispersive and non-perennial energy source due to its grid reliability, high efficiency, standalone modular design, and excellent cycling stability. However, the large vanadium ionic size and relatively high viscosity lead to poor compatibility with most carbon-based microporous electrodes, resulting in sluggish mass diffusion and unsatisfied capacitance retention. Herein, a novel cross-coupled porous graphene aerogel is proposed via the NaNO3-template pore engineering strategy. The microscopic observations and N2 adsorption-desorption isotherms validate the successful regulation of the surface area and porous structure, with the addition of different porogen contents (6.25-25 g L-1). The vanadium redox flow battery delivers a specific capacity of 163.4 mA h g-1 (5.6 A h L-1) at a current density of 25 mA cm-2, surpassing most previously reported batteries with a similar reactor volume. This method holds great promise for the better design and preparation of porous electrodes, and potential suitable applications.The photochemistry of molecules with peptide bonds is of both theoretical and experimental interest. Among these molecules, formamide (HCONH2) has been frequently selected as a representative in the study of proteins. Because several fundamental questions remained unanswered, particularly the role of thermal energy, the unimolecular photodissociations of HCONH2 were studied using the CASPT2(6,9)/aug-cc-pVDZ method and transition state theory (TST). The theoretical results verify that C-N dissociation is both kinetically and thermodynamically favorable in the S1 state. In addition, the dissociated radical products (HCO and NH2) could be precursors in the other dissociation channels owing to their high reactivities. The NH3-CO and NH3-OC H-bond complexes were reportedly observed to display the highest quantum yield in a UV experiment because the processes for determining the rates of isomerization dissociations of HCO and NH2 (which involve formyl hydrogen transfer) are spontaneous and kinetically favorable. Similarly, the van der Waals complex between HNCO and H2 represents the common end product with HCO and NH2 as the precursors.