Separation of Hemicellulose and Cellulose from Wood Pulp by Means of Ionic Liquid/Cosolvent Systems

Pulp of high cellulose content, also known as dissolving pulp, is needed for many purposes, including the production of cellulosic fibers and films. Paper-grade pulp, which is rich in hemicellulose, could be a cheap source but must be refined. Hitherto, hemicellulose extraction procedures suffered from a loss of cellulose and the non-recoverability of unaltered hemicelluloses. Herein, an environmentally benign fractionation concept is presented, using mixtures of a cosolvent (water, ethanol, or acetone) and the cellulose dissolving ionic liquid 1-ethyl-3-methylimidazolium acetate (EMIM OAc). This cosolvent addition was monitored using Kamlet–Taft parameters, and appropriate stirring conditions (3 h at 60 °C) were maintained. This allowed the fractionation of a paper-grade kraft pulp into a separated cellulose and a regenerated hemicellulose fraction. Both of these exhibited high levels of purity, without any yield losses or depolymerization. Thus, this process represents an ecologically and economically efficient alternative in producing dissolving pulp of highest purity

Additional file 1: Table S1. of Comparison of targeted next-generation sequencing and Sanger sequencing for the detection of PIK3CA mutations in breast cancer

Genomic positions and the primer sequences. (XLS 45 kb

High-Performance Acetylated Ioncell‑F Fibers with Low Degree of Substitution

Cellulose acetate is one of the most important cellulose derivatives. Herein we present a method to access cellulose acetate with a low degree of substitution through a homogeneous reaction in the ionic liquid 1,5-diazabicyclo[4.3.0]­non-5-enium acetate ([DBNH]­[OAc]). This ionic liquid has also been identified as an excellent cellulose solvent for dry-jet wet fiber spinning. Cellulose was dissolved in [DBNH]­[OAc] and esterified in situ to be immediately spun into modified cellulose filaments with a degree of substitution (DS) value of 0.05–0.75. The structural properties of the resulting fibers, which are characterized by particularly high tensile strength values (525–750 MPa conditioned and 315–615 MPa wet) and elastic moduli between 10–26 GPa, were investigated by birefringence measurements, wide-angle X-ray scattering, and molar mass distribution techniques while their unique interactions with water have been studied through dynamic vapor sorption. Thus, an understanding of the novel process is gained, and the advantages are demonstrated for producing high-value products such as textiles, biocomposites, filters, and membranes

Role of Solvent Parameters in the Regeneration of Cellulose from Ionic Liquid Solutions

The ionic liquids 1-ethyl-3-methylimidazolium acetate [emim]­OAc, <i>N</i>,<i>N</i>,<i>N</i>,<i>N</i>-tetramethylguanidium propionate [TMGH]­EtCO₂, and <i>N</i>,<i>N</i>,<i>N</i>,<i>N</i>-tetramethylguanidium acetate [TMGH]­OAc, and the traditional cellulose solvent <i>N</i>-methylmorpholine <i>N</i>-oxide NMMO were characterized for their Kamlet–Taft (KT) values at several water contents and temperatures. For the ionic liquids and NMMO, thresholds of regeneration of cellulose solutions by water were determined using nephelometry and rheometry. Regeneration from wet IL was found to be asymmetric compared to dissolution into wet IL. KT parameters were found to remain almost constant at temperatures, between 20–100 °C, even at different water contents. Among the KT parameters, the β value was found to change most drastically, with an almost linear decrease upon addition of water. The ability of the mixtures to dissolve cellulose was best explained by the difference β–α (net basicity), rather than β alone. Regeneration of cellulose starts at thresholds values of approximately β < 0.8 (β–α < 0.35) and displayed four phases

Oscillating Ferrofluid Droplet Microrheology of Liquid-Immersed Sessile Droplets

The damped oscillations of liquid-immersed ferrofluid sessile droplets were studied with high-speed imaging experiments and analytical modeling to develop a novel microrheology technique. Droplet oscillations were induced with an external magnetic field, thereby avoiding transients in the resulting vibrational response of the droplet. By following the droplet relaxation with a high-speed camera, the frequency and relaxation time of the damped harmonic oscillations were measured. We extend upon existing analytical theories to describe our liquid-immersed sessile droplet system, and directly quantify the droplet relaxation with the viscosity of the internal and external fluid as well as the interfacial tension between these. The easily controllable magnetic droplets make our oscillating ferrofluid droplet technique a potential candidate for high-throughput microrheology and tensiometry in the future

Oscillating Ferrofluid Droplet Microrheology of Liquid-Immersed Sessile Droplets

The damped oscillations of liquid-immersed ferrofluid sessile droplets were studied with high-speed imaging experiments and analytical modeling to develop a novel microrheology technique. Droplet oscillations were induced with an external magnetic field, thereby avoiding transients in the resulting vibrational response of the droplet. By following the droplet relaxation with a high-speed camera, the frequency and relaxation time of the damped harmonic oscillations were measured. We extend upon existing analytical theories to describe our liquid-immersed sessile droplet system, and directly quantify the droplet relaxation with the viscosity of the internal and external fluid as well as the interfacial tension between these. The easily controllable magnetic droplets make our oscillating ferrofluid droplet technique a potential candidate for high-throughput microrheology and tensiometry in the future

Dialkyl Phosphate-Related Ionic Liquids as Selective Solvents for Xylan

Herein we describe a possibility of selective dissolution of xylan, the most important type of hemicellulose, from <i>Eucalyptus globulus</i> kraft pulp using ionic liquids (ILs). On the basis of the IL 1-butyl-3-methylimidazolium dimethyl phosphate, which is well-known to dissolve pulp, the phosphate anion was modified by substituting one oxygen atom for sulfur and selenium, respectively. This alteration reduces the hydrogen bond basicity of the IL and therefore prevents dissolution of cellulose fibers, whereas the less ordered xylan is still dissolved. ¹H NMR spectra of model solutions and Kamlet–Taft parameters were used to quantify the solvent polarity and hydrogen bond acceptor properties of the ILs. These parameters have been correlated to their ability to dissolve xylan and cellulose, which was monitored by ¹³C NMR spectroscopy. It was found that the selectivity for xylan dissolution increases to a certain extent with decreasing hydrogen-bond-accepting ability of anions of the ILs

Patient characteristics collected from the patient management software and the regional population-based cancer registry (n = 129).

<p>Patient characteristics collected from the patient management software and the regional population-based cancer registry (n = 129).</p

Immunohistochemical biomarker analysis: All immunohistochemical markers except Ki-67, TP53, and Survivin were analyzed using the semiquantitative scoring system described in the method section.

<p>Immunohistochemical biomarker analysis: All immunohistochemical markers except Ki-67, TP53, and Survivin were analyzed using the semiquantitative scoring system described in the method section.</p

Immunhistochemical and H&E staining of the TMA of gastric cancer specimens (200x).

<p>Poorly differentiated medullary cancer by H&E staining (A) and CD3 staining (B). TP53 mutated (C) and wildtype (D) tumor sample.</p