Chemical characterization and ultrastructure study of pulp fibers

Understanding the ultrastructure and chemical characterization of pulp fibers is highly important in utilizing wood as a raw material in a wide scope of applications, such as forest biomass-based biorefineries and low-cost renewable materials. The observation of the ultrastructure is not possible without advanced microscopy and spectroscopy techniques. Therefore, this study focuses on exploring the ultrastructure of pulp fibers with helium ion microscopy (HIM) and scanning electron microscopy (SEM). For the analysis of chemical characterization in the pulp fibers, Raman spectroscopy, Fourier transform infrared spectroscopy (FT-IR), and X-ray photoelectron spectroscopy (XPS) were performed. For these studies, the pulp fiber samples were obtained mainly from three different wood species, i.e. spruce, birch and eucalyptus. They were received in the never dried state and dried with a critical point drier (CPD) to minimize pore collapse. The spectroscopy results showed a strong signal from crystalline cellulose and confirmed the absence of lignin after Kraft pulping and bleaching. However, with XPS about 2% of lignin was detected in eucalyptus pulp. The results obtained with the microscopy techniques are compared and indicating the nanofibril size, shape, surface roughness as well as their orientation in pulp fibers. To our knowledge, this is the first time that HIM is applied to study the ultrastructure of pulp fibers and compared against more conventional microscopy and spectroscopy techniques. The main differences between HIM and SEM were found to be related to the focusing and magnification. The individual nano- and microfibrils as well as their bundles were more easily visible with HIM than with SEM. Also, with HIM it was possible to get the total area in focus at once which was not the case with SEM. The increased understanding of the ultrastructure and chemical composition of wood pulp enhance the development of novel wood-based products and processes for their manufacture.     

Superhydrophobic polyolefin surfaces: controlled micro- and nanostructures

Superhydrophobic polyolefin surfaces were prepared by simultaneous micro- and nanostructuring. Electropolished aluminum foil was microstructured with a micro working robot and then anodized in polyprotic acid. The surface microstructure can be tailored by adjusting the settings of the micro working robot and the nanostructure by adjusting the parameters of the anodization procedure. Surface structuring was done by injection molding where a microstructured anodized aluminum oxide mold insert was used to pattern the surfaces. Structuring had a marked effect on the contact angle between the injection-molded polyolefins and water. When the optimized microstructure was covered with nanostructure, the static contact angle between polypropylene and water obtained a value of about 165 degrees and the sliding angle decreased to about 2.5 degrees. The superhydrophobic state was achieved.     

Chemical Proteomics and Phenotypic Profiling Identifies the Aryl Hydrocarbon Receptor as a Molecular Target of the Utrophin Modulator Ezutromid

Duchenne muscular dystrophy (DMD) is a fatal muscle‐wasting disease arising from mutations in the dystrophin gene. Upregulation of utrophin to compensate for the missing dystrophin offers a potential therapy independent of patient genotype. The first‐in‐class utrophin modulator ezutromid/SMT C1100 was developed from a phenotypic screen through to a Phase 2 clinical trial. Promising efficacy and evidence of target engagement was observed in DMD patients after 24 weeks of treatment, however trial endpoints were not met after 48 weeks. The objective of this study was to understand the mechanism of action of ezutromid which could explain the lack of sustained efficacy and help development of new generations of utrophin modulators. Using chemical proteomics and phenotypic profiling we show that the aryl hydrocarbon receptor (AhR) is a target of ezutromid. Several lines of evidence demonstrate that ezutromid binds AhR with an apparent K_D of 50 nm  and behaves as an AhR antagonist. Furthermore, other reported AhR antagonists also upregulate utrophin, showing that this pathway, which is currently being explored in other clinical applications including oncology and rheumatoid arthritis, could also be exploited in future DMD therapies.     

Forcing a Boolean algebra with predesigned automorphism group

For suitable groups we will show that one can add a Boolean algebra by forcing in such a way that is almost isomorphic to . In particular, we will give a positive answer to the following question due to J. Roitman: Is a possible number of automorphisms of a rich Boolean algebra?

     

Hardy's inequality for -functions on Riemannian manifolds

We prove that for every Riemannian manifold with the isoperimetric profile of particular type there holds an inequality of Hardy type for functions of the class . We also study manifolds satisfying Hardy's inequality and, in particular, we establish an estimate for the rate of growth of the weighted volume of the noncompact part of such a manifold.

     

Assembly of the Au-diphosphine helical cage molecules via alkynyl-μ4-methylydine ligand transformation

The assembly of the gold(I)-diphosphine cages occurs via unprecedented transformation of the alkynyls into the μ(4)-methylydine ligands under basic conditions. These compounds demonstrate the equilibrium between the P?M helical isomers and serve as hosts to accommodate small molecules (CH(2)Cl(2) and CS(2)).