Two constitutional structural schemes are proposed attempting to unify and rationalize a series of focused NMR and chromatographic determinations aimed at providing an integrated picture for the structure of softwood kraft lignin.

ABSTRACT:The mechanism (or mechanisms) of enthalpy− entropy (H/S) compensation in protein−ligand binding remains controversial, and there are still no predictive models (theoretical or experimental) in which hypotheses of ligand binding can be readily tested. Here we describe a particularly well-defined system of protein and ligandshuman carbonic anhydrase (HCA) and a series of benzothiazole sulfonamide ligands with different patterns of fluorinationthat we use to define enthalpy/entropy (H/S) compensation in this system thermodynamically and structurally. The binding affinities of these ligands (with the exception of one ligand, in which the deviation is understood) to HCA are, despite differences in fluorination pattern, indistinguishable; they nonetheless reflect significant and compensating changes in enthalpy and entropy of binding. Analysis reveals that differences in the structure and thermodynamic properties of the waters surrounding the bound ligands are an important contributor to the observed H/S compensation. These results support the hypothesis that the molecules of water filling the active site of a protein, and surrounding the ligand, are as important as the contact interactions between the protein and the ligand for biomolecular recognition, and in determining the thermodynamics of binding.

Lignin is the second most abundant natural polymer. Its use and targeted functionalisation within biomass refinery processes, however, still needs to be further explored and devel- oped. The oxidative functionalisation, and thus valorisation of lignin, is a very promising way to go, since it holds the possibilities to yield highly functionalised, monomeric or olig- omeric products that can serve as starting materials for other valorisation processes in the chemical and pharmaceutical industries. Gaining a profound knowledge about the struc- ture of lignin, being able to analyse structural features, and understanding the mechanisms that guide the reactions leading to the oxidative derivatisation, depolymerisation and func- tionalisation of lignin samples from different renewable sources are key requirements for developing successful valorisation protocols for lignin. In this review, we wish to revisit, and set into context, some important achievements in the field of oxidatively upgrading lignin. We will focus on organometal catalyses (MTO, salen complexes, POMs), biomimetic catalyses (porphyrins), and enzymatic catalyses (laccase, peroxidase) for upgrading lignin and lignin model compounds. Details of mechanistic implications and means of potential manipulations of reaction outcomes are discussed

The mechanism of lignin nanoprecipitation and subsequent self-assembly was elucidated by studying generation of lignin nanoparticles (LNPs) from aqueous ethanol. LNP formation was found to follow a kinetically controlled nucleation–growth mechanism in which large lignin molecules formed the initial critical nuclei. Using this information, we demonstrate entrapment of budesonide in LNPs and subsequent pH-triggered and surfactant-responsive release of this synthetic anti-inflammatory corticosteroid. Overall, our results not only provide a promising intestinal delivery system for budesonide but also deliver fundamental mechanistic understanding for the entrapment of actives in LNPs with controlled size and release properties.

This paper describes the fabrication and properties of "fluoroalkylated paper" ("R F paper") by vapor-phase silanization of paper with fluoroalkyl trichlorosilanes. R F paper is both hydrophobic and oleophobic: it repels water (θ app H 2 O >140°), organic liquids with surface tensions as low as 28 mN/m, aqueous solutions containing ionic and non-ionic surfactants, and complex liquids such as blood (which contains salts, surfactants, and biological material such as cells, proteins, and lipids). The propensity of the paper to resist wetting by liquids with a wide range of surface tensions correlates (with a few exceptions) with the length and degree of fluorination of the organosilane, and with the roughness of the paper. R F paper 2 maintains the high permeability to gases, and the mechanical flexibility of the untreated paper, and can be folded into functional shapes (e.g. microtiter plates and liquid-filled gas sensors).When impregnated with a perfluorinated oil, R F paper forms a "slippery" surface (paper slippery liquid-infused porous surface, or "paper SLIPS") capable of repelling liquids with surface tensions as low as 15 mN/m. The foldability of the paper SLIPS allows the fabrication of channels and flow switches to guide the transport of liquid droplets.

A newly developed ReactIR flow cell is reported as a convenient and versatile inline analytical tool for continuous flow chemical processing. The flow cell, operated with ATR technology, is attached directly into a reaction flow stream using standard OmniFit (HPLC) connections and can be used in combination with both meso- and microscale flow chemistry equipment. The iC IR analysis software (version 4.0) enables the monitoring of reagent consumption and product formation, aiding the rapid optimisation of procedures. Short-lived reactive intermediates can also be observed in situ, giving further mechanistic insight into complex transformations.

To liberate society from its dependence on fossil‐based fuels and materials it is pivotal to explore components of renewable plant biomass in applications that benefit from their intrinsic biodegradability, safety, and sustainability. Lignin, a byproduct of the pulp and paper industry, is a plausible material for carrying various types of cargo in small‐ and large‐scale applications. Herein, possibilities and constraints regarding the physical–chemical properties of the lignin source as well as modifications and processing required to render lignins suitable for the loading and release of pesticides, pharmaceuticals, and biological macromolecules is reviewed. In addition, the technical challenges, regulatory and toxicological aspects, and future research needed to realize some of the promises that nano‐ and microscaled lignin materials hold for a sustainable future are critically discussed.

This study has shown that ultrafiltration allows the selective extraction from industrial black liquors of lignin fraction with specific thermo-mechanical properties, which can be matched to the intended end uses. Ultrafiltration resulted in the efficient fractionation of kraft lignin according to its molecular weight, with an accumulation of sulfur-containing compounds in the lowmolecular weight fractions. The obtained lignin samples had a varying quantities of functional groups, which correlated with their molecular weight with decreased molecular size, the lignin fractions had a higher amount of phenolic hydroxyl groups and fewer aliphatic hydroxyl groups. Depending on the molecular weight, glass-transition temperatures (T g ) between 70 and 170 C were obtained for lignin samples isolated from the same batch of black liquor, a tendency confirmed by two independent methods, DSC, and dynamic rheology (DMA). The Fox-Flory equation adequately described the relationship between the number average molecular masses (M n ) and T g 's-irrespective of the method applied. DMA showed that low-molecular-weight lignin exhibits a good flow behavior as well as high-temperature crosslinking capability. Unfractionated and high molecular weight lignin (M w >5 kDa), on the other hand, do not soften sufficiently and may require additional modifications for use in thermal processings where melt-flow is required as the first step.