Salt-induced acceleration of chemical reactions in cellulose nanopores

Chemical reactions in charged nanopores, such as present in cellulose fibers, can be accelerated by adding an inert salt, that does not participate in the reaction. Due to a Donnan-like equilibrium between ions inside and outside the pores, the concentration of co-ions in the nanopores (having a charge of the same sign as that of the pore wall), is lower than the concentration in the bulk. The co-ion concentration in pores can be increased by adding an inert salt, which shifts the Donnan equilibrium. The increased concentration of reactants in pores results in faster reaction kinetics. Reactions of cellulose with periodate confirm these predictions.     

2,3,7,8,12,13-Hexakis[2-(2-methoxyethoxy)ethoxy]tricycloquinazoline: a discogen which allows enhanced levels of n-doping

A synthesis has been developed for 2,3,7,8,12,13-hexakis[2-(2-methoxyethoxy)ethoxy]-tricycloquinazoline (TCQ6EO2M) in which the ethylenoxy side chains are introduced before elaboration of the heterocylic core. This discogen gives a hexagonal columnar phase (Col_h) between 77 and 233°C. n-Doping using potassium metal is facilitated firstly by the electron poor/π-deficient nature of the core and secondly by the polyethylenoxy side chains which complex the potassium K⁺ counter-ions. The conductivity of the Col_h phase of TCQ6EO2M doped with 10 mol % potassium (σ _∥ = 1.1 x 10^-3 S m^-1) is substantially higher than that previously reported for 2,3,7,8,12,13-hexa(hexylthio)tricycloquinazoline doped with 6 mol % potassium (σ _∥ = 2.9 x 10^-5 S m^-1). Photoconductivity studies of TCQ6EO2M using a time of flight sample configuration show transient photocurrents for both holes and electrons. From these an upper limit on the mobility for the electrons is estimated as ~10^-4 cm² V^-1 s^-1 at 150°C which is of the same magnitude as that for hole mobilities in other columnar discotic liquid crystals.     

A new approach to untargeted integration of high resolution liquid chromatography–mass spectrometry data

Because of its high sensitivity and specificity, hyphenated mass spectrometry has become the predominant method to detect and quantify metabolites present in bio-samples relevant for all sorts of life science studies being executed. In contrast to targeted methods that are dedicated to specific features, global profiling acquisition methods allow new unspecific metabolites to be analyzed. The challenge with these so-called untargeted methods is the proper and automated extraction and integration of features that could be of relevance. We propose a new algorithm that enables untargeted integration of samples that are measured with high resolution liquid chromatography–mass spectrometry (LC–MS). In contrast to other approaches limited user interaction is needed allowing also less experienced users to integrate their data. The large amount of single features that are found within a sample is combined to a smaller list of, compound-related, grouped feature-sets representative for that sample. These feature-sets allow for easier interpretation and identification and as important, easier matching over samples. We show that the automatic obtained integration results for a set of known target metabolites match those generated with vendor software but that at least 10 times more feature-sets are extracted as well. We demonstrate our approach using high resolution LC–MS data acquired for 128 samples on a lipidomics platform. The data was also processed in a targeted manner (with a combination of automatic and manual integration) using vendor software for a set of 174 targets. As our untargeted extraction procedure is run per sample and per mass trace the implementation of it is scalable. Because of the generic approach, we envision that this data extraction lipids method will be used in a targeted as well as untargeted analysis of many different kinds of TOF-MS data, even CE- and GC–MS data or MRM. The Matlab package is available for download on request and efforts are directed toward a user-friendly Windows executable.     

Formation of cellulose microspheres and nanocrystals from mildly carboxylated fibers

Cellulose - The ultrastructure of mildly carboxylated swollen tracheids from which cellulose microspheres and cellulose nanocrystals (CNC) were formed was investigated. A mild etherification of...     

Production of textile filaments from carboxymethylated cellulosic pulps

Cellulose - Textile filaments were fabricated from a solution obtained from carboxymethylated cellulose dissolved in aqueous NaOH solution, by wet spinning in an acid coagulation bath. Spinning is...     

X-ray photoelectron spectroscopy and Raman microscopy of a ferroan platinum crystal from the Kondyor Massif,Russian Far East

X-ray Photoelectron Spectroscopy was used to study a ferroan platinum crystal from the Kondyor Massif, Russian Far East. Prior to the X-ray Photoelectron Spectroscopic analyses, the nature of the crystal was confirmed by X-ray diffraction. The survey scan showed mainly the presence of Pt and Fe, with smaller amounts of O and Si. The high resolutions spectra of the Pt 4f and Fe 2p showed 18.3 atom% Fe in the crystal, which puts the composition on the lower boundary for ferroan platinum and confirms earlier analyses using other methods such as Scanning Electron Microscopy-Energy Dispersive X-ray analysis/microprobe. The binding energy of the Pt 4f5/2 was 74.0?eV and Pt 4f7/2 70.5?eV, while the Fe 2p3/2 for metallic Fe was observed at 707.2?eV. The Fe 2p3/2 for metallic Fe was significantly sharper than that of Fe 2p3/2 at 710.7?eV associated with surface material. The Raman spectrum was dominated by the Pt–Pt stretching mode at 253?cm^?1. Changed orientation resulted in the observation of two bands at 127 and 139?cm^?1, interpreted as being due to stretching modes of two Pt–Pt bonds with the third bond to Fe and Pt fixed. The presence of Ca-Fe-Al-Mg-Si-O on the surface was probably associated with the presence of a clinopyroxene. These minerals can be expected since the crystal came originally from a clinopyroxenite-dunite matrix. The spectra showed a variety of interferences, e.g. Al 2p with Pt 4f, Mg 2p with Fe 3p, and Ca 2p1/2 with Mg Auger, making exact determinations of the ratios of these elements difficult.