Search

Micro-spectral analysis and fluorescence decay experiments of beech and oak chips as well as their main constituents lignin and cellulose are reported. While the lignin spectrum shows two fluorescence bands of almost identical intensity around 500 nm and 560 nm, the cellulose spectrum is dominated by a band around 500 with a less pronounced shoulder at 560 nm, whose intensity increases with the amount of residual lignin. Fluorescence decay kinetics are bi-exponential with lifetimes around 0.5 ns and 2.5 ns and an increasing contribution of the short-lived component with an increasing amount of lignin. Both data sets indicate that a quantification of residual lignin in cellulose samples obtained after decomposition of beech wood appears possible in a concentration range of 2–10 %. This may provide a non-destructive and label-free test of the quality of decomposition.

Recently, an African ancestry-specific Parkinson disease (PD) risk signal was identified at the gene encoding glucocerebrosidase (GBA1). This variant (rs3115534-G) is carried by ~50% of West African PD cases and imparts a dose-dependent increase in risk for disease. The risk variant has varied frequencies across African ancestry groups but is almost absent in European and Asian ancestry populations. GBA1is a gene of high clinical and therapeutic interest. Damaging biallelic protein-coding variants cause Gaucher disease and monoallelic variants confer risk for PD and dementia with Lewy bodies, likely by reducing the function of glucocerebrosidase. Interestingly, the African ancestry-specific GBA1risk variant is a noncoding variant, suggesting a different mechanism of action. Using full-length RNA transcript sequencing, we identified partial intron 8 expression in risk variant carriers (G) but not in nonvariant carriers (T). Antibodies targeting the N terminus of glucocerebrosidase showed that this intron-retained isoform is likely not protein coding and subsequent proteomics did not identify a shorter protein isoform, suggesting that the disease mechanism is RNA based. Clustered regularly interspaced short palindromic repeats editing of the reported index variant (rs3115534) revealed that this is the sequence alteration responsible for driving the production of these transcripts containing intron 8. Follow-up analysis of this variant showed that it is in a key intronic branchpoint sequence and, therefore, has important implications in splicing and disease. In addition, when measuring glucocerebrosidase activity, we identified a dose-dependent reduction in risk variant carriers. Overall, we report the functional effect of a GBA1noncoding risk variant, which acts by interfering with the splicing of functional GBA1transcripts, resulting in reduced protein levels and reduced glucocerebrosidase activity. This understanding reveals a potential therapeutic target in an underserved and underrepresented population.

Graphical Abstract:

Niemann-Pick type C1 disease (NPC1 [OMIM 257220]) is a rare and severe autosomal recessive disorder, characterized by a multitude of neurovisceral clinical manifestations and a fatal outcome with no effective treatment to date. Aiming to gain insights into the genetic aspects of the disease, clinical, genetic, and biomarker PPCS data from 602 patients referred from 47 countries and diagnosed with NPC1 in our laboratory were analyzed. Patients’ clinical data were dissected using Human Phenotype Ontology (HPO) terms, and genotype–phenotype analysis was performed. The median age at diagnosis was 10.6 years (range 0–64.5 years), with 287 unique pathogenic/likely pathogenic (P/LP) variants identified, expanding NPC1allelic heterogeneity. Importantly, 73 P/LP variants were previously unpublished. The most frequent variants detected were: c.3019C > G, p.(P1007A), c.3104C > T, p.(A1035V), and c.2861C > T, p.(S954L). Loss of function (LoF) variants were significantly associated with earlier age at diagnosis, highly increased biomarker levels, and a visceral phenotype (abnormal abdomen and liver morphology). On the other hand, the variants p.(P1007A) and p.(S954L) were significantly associated with later age at diagnosis (p< 0.001) and mildly elevated biomarker levels (p≤ 0.002), consistent with the juvenile/adult form of NPC1. In addition, p.(I1061T), p.(S954L), and p.(A1035V) were associated with abnormality of eye movements (vertical supranuclear gaze palsy, p≤ 0.05). We describe the largest and most heterogenous cohort of NPC1 patients published to date. Our results suggest that besides its utility in variant classification, the biomarker PPCS might serve to indicate disease severity/progression. In addition, we establish new genotype–phenotype relationships for “frequent” NPC1variants.

Lignin is a complex macromolecule that possesses a high potential for various material-based applications in the near future. In order to retrieve this potential, more detailed knowledge about the structural composition of lignin is required. One possible way to solve this problem is the application of ultrahigh resolving analysis methods such as Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS). In most studies from the last years, mainly dissolved lignin compounds, which only represent a fraction of the overall sample, were utilized for MS investigations. In this study, both soluble and insoluble lignin compounds of three different lignins (Kraft and Lignoboost lignins) were analyzed by electrospray ionization (ESI) and graphite-assisted laser desorption/ionization (GALDI) in combination with FT-ICR-MS. The different MS analyses demonstrated that ESI- and liquid GALDI-MS analyses can assist in the characterization of lignin molecules, which possess a high solubility in solvents of high polarity. In contrast, solid GALDI-MS provides insights about less polar molecules that have a low solubility in most solvents. Due to this higher molecular range of analyzable lignin compounds, the novel results will, hopefully, help to improve our understanding of the lignin structure and to utilize this interesting biopolymer in a more expedient and efficient way in the future.

Gas sensors based on micro‐electromechanical systems (MEMS) offer advantages such as a broad spectrum of potentially sensitive materials and analytes, easy miniaturization and integration, high sensitivity, and low costs. This paper introduces a novel MEMS sensor platform utilizing a suspended gate field effect transistor (SGFET) transducer. In this approach, the flexible gate membrane of the SGFET is coated with a sensitive material exhibiting responsive swelling behavior. For the proof of concept, kraft lignin hydrogel is chosen as a biorenewable material for humidity sensing. A precision dispensing technique is used to deposit kraft lignin hydrogel on the SGFETs. The sensor measurements yield reversible shifts in the sensor's output current of up to 9% in response to 5000 ppm water vapor. The results successfully demonstrate the feasibility of this new sensing platform. A novel MEMS sensor platform utilizing a suspended gate field effect transistor (SGFET) transducer is introduced. In this approach, the flexible gate membrane of the SGFET is coated with a sensitive material exhibiting responsive swelling behavior. For the proof of concept, kraft lignin hydrogel is chosen as a biorenewable material for humidity sensing.

Thin films of cellulose ferulate were designed to study the formation of dehydrogenation polymers (DHPs) on anchor groups of the surface. Trimethylsilyl (TMS) cellulose ferulate with degree of substitution values of 0.35 (ferulate) and 2.53 (TMS) was synthesized by sophisticated polysaccharide chemistry applying the Mitsunobu reaction. The biopolymer derivative was spin-coated into thin films to yield ferulate moieties on a smooth cellulose surface. Dehydrogenative polymerization of coniferyl alcohol was performed in a Quartz crystal microbalance with a dissipation monitoring device in the presence of H2O2and adsorbed horseradish peroxidase. The amount of DHP formed on the surface was found to be independent of the base layer thickness from 14 to 75 nm. Pyrolysis-GC-MS measurements of the DHP revealed β-O-4 and β-5 linkages. Mimicking lignification of plant cell walls on highly defined model films enables reproducible investigations of structure–property relationships.

Supercapacitors with carbonaceous electrode materials represent an efficient energy storage system with a long lifetime and high power density. In this work, we elaborated a route to prepare hard carbons with specified surface properties and tailored pore structures using pyrolysis of cellulose and cellulose acetate microspheres, which are environmentally friendly and sustainable materials in comparison to other carbon sources. In order to enhance the specific surface area of carbons, a facile activation with various amounts of KOH was carried out. Carbonized cellulose acetate without activation shows specific surface areas of about 440 m2g–1and after activation up to 1200 m2g–1. Activated carbon electrodes provide a specific capacitance of 186 F g–1at a scan rate of 10 mV s–1in symmetric supercapacitors with an aqueous 4 M KOH electrolyte, providing a high energy density of 40 Wh kg–1at a power density of 15 kW kg–1. While using neutral electrolytes (1 M Li2SO4and 1 M Na2SO4), a capacitance of 120 F g–1was achieved with a maximal power density of 21 kW kg–1. Since many parameters influence the electrochemical performance of carbons, a correlation between synthesis conditions, structural, and electrochemical properties was elaborated. Overall, it was shown that carbons, based on spherical cellulose and cellulose acetate microparticles, represent promising electrode materials for aqueous supercapacitors in terms of their simple and reliable preparation procedure and electrochemical performance.

In a previous paper we have demonstrated that the easily-synthesized class of iron(0) cyclopentadienone complexes constitutes a promising catalyst platform for the electrochemical conversion of CO2to CO and H2O. One of the unusual features of these catalysts is that catalysis proceeds efficiently in aprotic electrolytes in the absence of acidic additives. Herein we present a detailed study of the underlying catalytic mechanisms. Using a combination of FTIR spectroelectrochemistry, DFT calculations, and nonelectrochemical control experiments, we have identified a number of catalytic intermediates including the active species and the product of catalyst deactivation. On the basis of these insights, we have carried out digital simulations in order to decipher the voltammetric profiles of the iron(0) cyclopentadienones. Further control experiments revealed that the anodic oxidation of the electrolyte constitutes the terminal proton source for the formation of CO and H2O. Taken together, our results suggest a competition between two coexisting catalytic pathways, one of which proceeds via a hitherto unknown Fe–Fe dimer as an active species.

Cracks, formed during the drying of particulate films, can reduce the effectiveness or even render products useless. We present a novel, generic approach to suppress crack formation in thin films made from hard particle suspensions, which are otherwise highly susceptible to cracking, using the capillary force between particles present when a trace amount of an immiscible liquid is added to a suspension. This secondary liquid preserves the particle cohesion, modifying the structure and increasing the drying rate. Crack-free films can be produced at thicknesses much greater than the critical cracking thickness for a suspension without capillary interactions, and even persists after sintering. This capillary suspension strategy is applicable to a broad range of materials, including suspensions of metals, semiconductive and ceramic oxides, or glassy polymeric particles, and can be easily implemented in many industrial processes since it is based on well-established unit operations. Promising fields of application include ceramic foils and printed electronic devices.

In this work the influence of the SoC and the SoH on the thermal runaway was analyzed in depth (SoC 30–100 % /SoH 75–100 %). Generally, the results show a decrease in the strength of the TR reactions with decreasing SoC/SoH.

The performance of symmetric supercapacitors with activated carbon electrodes, obtained from cellulose acetate microspheres as a precursor, has been studied using neutral aqueous sodium sulphate solutions as electrolytes. Although water-based electrolytes can safely operate in a broad temperature range, studies of supercapacitors beyond conventional room temperature conditions are rather limited, while most of investigations are focused on ionic liquids as electrolytes. However, since water represents a cheap, easy to handle and environmentally friendly solvent, detailed temperature investigations of supercapacitors with aqueous electrolytes are of importance. In the present work, we evaluated the behaviour of supercapacitors with electrolytes having various Na2SO4concentrations, in a temperature range between 0 °C and 60 °C. Since stable and safe operation of supercapacitors with carbon electrodes exclusively depends on the electrolyte properties at these non-ambient conditions, the electrolytes were characterized with regard to their conductivity and viscosity at various temperatures. Activated carbon materials were produced by a one-step carbonization procedure of home-made cellulose acetate microspheres (CAM) using KOH as an activator, which was added to cellulose acetate microspheres in form of a solution for better homogenization. Supercapacitors with a neutral 1 M Na2SO4solution as the best electrolyte composition were tested between 0 °C and 60 °C and provided specific capacitances between 91 F g−1and 117 F g−1, demonstrating a good cycling stability with a retention of at least 95 % of the initial capacitance over 2000 cycles. Energy densities of 16.6 Wh kg−1at a power density of 16 kW kg−1are provided at 25 °C, whereas the energy density is improved at 60 °C to 21.5 Wh kg−1at a slightly lower power density of 13.7 kW kg−1. No sign of electrochemical corrosion of battery housings was observed after cycling, in contrast to acid-based electrolytes with H2SO4tested for comparison.

The biofunctionalization of CdSe/CdS/ZnS quantum dots and Fe3O4nanocrystals using a novel ligand system based on polyisoprene-block-poly(ethylene oxide) ligands is described. The synthesis includes a partial ligand exchange of the hydrophobic nanocrystals with amino-functionalized polyisoprene ligands, followed by seeded micelle formation of the diblock-copolymers in water. The resulting water-soluble quantum dots showed fluorescence quantum efficiencies in the 40 to 50% range and extraordinary fluorescence stability in the biological environment after cross-linking of the polyisoprene moiety of the ligand shell. No toxicity was detected by water-soluble tetrazolium (WST8) and lactate dehydrogenase (LDH) assays, even at very high nanoparticle concentrations, and almost no nonspecific cell adhesion was detected. The ligand shell was further coupled to the antigen-related cell adhesion molecule (CEACAM) specific monoclonal antibody T84.1. The so-conjugated Fe3O4nanocrystals allowed in vitroand in vivotumor targeting by magnetic resonance imaging.

Eine Polymerbürstenschichtauf der Oberfläche von Nanopartikeln macht diese mit der Polymermatrix mischbar. Über die Länge der angebundenen Polymerketten lässt sich der Abstand zwischen benachbarten Nanopartikeln genau einstellen (siehe Bild).

Mixing in: Attachment of a polymer‐brush layer to the surface of nanoparticles makes the nanoparticles miscible with the polymer matrix. Adjusting the length of the attached polymer chains enables exact control of the distance between adjacent nanoparticles (see picture).

Radiolabeled vesamicol analogs are promising candidates as ligands for the vesicular acetylcholine transporter (VAChT) to enable in vivoimaging of early cholinergic degenerations in brain. The 4‐fluorobenzoyl‐substituted azaspirovesamicol derivative FBASV is one out of six novel vesamicol analogs and demonstrated most appropriate in vitrobinding data. 18F‐radiolabeling was performed by microwave‐assisted nucleophilic aromatic substitution of the corresponding nitro precursor and two methods were developed for the purification of [18F]FBASV. Utilizing method A, the remaining nitro precursor was reduced to its corresponding amine, which was separated via semi‐preparative HPLC on a conventional RP column. In method B a phenyl column was used for the direct separation of [18F]FBASV and its nitro precursor, resulting in a change of the elution order and better separation parameters. Thus, [18F]FBASV was synthesized with a RCY of 16–18%, a specific activity >300 GBq/µmol, and a radiochemical purity of >99.5% suitable for future in vivostudies. Copyright © 2011 John Wiley & Sons, Ltd.

Therapeutic apheresis is established as supportive therapy for various diseases, such as hypercholesterolemia, autoimmune diseases, liver failure, and sepsis. In combined membrane‐adsorption systems, the patient's plasma is continuously separated from whole blood by means of a hollow fiber filter, and pathogenic factors are removed from the plasma by selective or specific adsorbents. While adsorbent particles with a size range of 300–800 µm are used in conventional systems, we are currently developing a system based on adsorbent microparticles (1–5 µm), the Microspheres‐Based Detoxification System (MDS). The characteristics of the matrix used for immobilization of specific ligands influence the performance of the resulting adsorbents. Desirable matrix characteristics are an open porous structure with an inner surface accessible for target molecules, mechanical stability, narrow particle size distribution, and ease of derivatization. In addition, biocompatibility is a critical issue, since the particles are in direct contact with the patient's plasma. Cellulose represents an ideal support matrix, as it combines all the above‐mentioned features, and cellulosic polymers are widely applied in medicine and generally regarded as biocompatible. Cellulose microparticles can be activated using e.g. sodium periodate and functionalized with Polymyxin B or anti‐tumor necrosis factor (TNF) antibodies to generate specific adsorbents for endotoxins or TNF. In summary, cellulose microparticles represent an excellent matrix as basis for adsorbent development in blood purification.

Summary:A new kind of very fine disperse porous bead cellulose is modified by chemical treatments to 2,3‐dialdehyde cellulose, carboxymethyl and dihydrogenphosphate cellulose. Model drugs like benzocaine and prazosin are coupled to these modified bead celluloses by covalent and ionic linkage, respectively and compressed to tablets. Compression mixtures with low loaded benzocaine conjugates release with medium rate. Linkage of prazosin cation to the anionic derivatives of bead cellulose leads to fast release of poor soluble ionic drug.

Summary:Cellulose derivatives having carboxyl‐ or carboxymethyl‐ and sulphate groups were synthesized with control of reaction conditions to regulate the distribution of substituents and molecular weights of the products. Sodium cellulose sulphates (NaCS) were synthesized through acetosulphation of cellulose or direct sulphating of cellulose and cellulose‐2.5‐acetate (C2.5A). The properties of the products were controlled by choice of starting materials and reaction parameters like reaction temperature and duration. Cellulose sulphates containing carboxyl groups were prepared through oxidation with 2,2,6,6‐tetramethylpiperidine‐1‐oxyl radical (TEMPO)/NaBr/NaClO in water or through carboxymethylation with chloroacetic acid after alkali treatment with sodium hydroxide. The biological activity of the products was analyzed with a binding assay to fibroblast growth factor (b‐FGF). It was found that NaCS with maximum O‐6‐sulfation and intermediate to high O‐2‐sulfation was able to bind b‐FGF comparable to natural heparin. Products being sulphated and afterwards carboxymethylated at all three positions were also able to bind substantial quantities of b‐FGF.

Summary: Pulp reactivity is a kinetic term and is always connected with a certain derivatization process. The quality and hence the market value of the pulp is determined by such characteristics as α‐ cellulose content, solubility, brightness, ash content, as well as the amount of soluble material in dichloromethane. However, solubility data, especially S18and S10values do not characterise dissolving pulp reactivity. These are indicative of pulp solubility and provide some information regarding losses of material during pulp processing. One way by which the pulp reactivity for viscose making can be characterised is the investigation of the mercerisation step. Following the mercerisation kinetics by help of the molecular weight distribution of cellulose II the behaviour especially of the high molecular weight cellulose gives information regarding the accessibility and therefore, about the reactivity of the pulp aside from losses in low molecular weight cellulose. This behaviour will be shown on different pulps and the physicochemical background will be discussed in relation to results obtained from wide angle X‐ray scattering and Raman investigations. The influence of the behaviour of the pulp during mercerising on the viscose process, and the molecular weight distribution of the viscose including the distribution of the xanthogenate groups along the chain was investigated and will also be discussed.

The involvement of gamma amino butyric acid (GABA) receptors in a variety of neurological and psychiatric diseases has promoted the development and use of radiolabelled benzodiazepines (BZ) for brain imaging by PET. However, these radioligands are unable to distinguish between the various subtypes of GABAA receptors. Novel non‐BZ such as the pyrazolo‐pyrimidine indiplon proved to be selective for the α1‐subunit of the GABAA receptor. Here, we describe the syntheses of four novel 18F‐labelled indiplon derivatives. Radiosyntheses were performed via n.c.a. 18F‐nucleophilic substitution starting from the tosyl, bromo, and 4‐nitrobenzoyl precursors to obtain fluorine substituted N‐alkylamide side chain derivatives of indiplon, followed by multistep purification using semi‐preparative high‐performance liquid chromatography and solid phase extraction. Tosyl and bromo precursors were converted into 18F‐labelled indiplon derivatives with good and reproducible radiochemical yield (RCY) (35–70%, decay corrected), high radiochemical purity (≥98.5%), and high specific activity ( > 150 GBq/µmol). By contrast, a low RCY (5–10%) and specific activity (10–15 GBq/µmol) were achieved for the 4‐nitrobenzoyl precursor. Copyright © 2008 John Wiley & Sons, Ltd.

Regioselectively substituted cellulose sulfates in C2/3‐, C2/6‐, or C6‐position of the anhydroglucose unit are accessible by certain synthesis routes. Thereby, products with different properties and various application areas are resulted. Important characteristics of cellulose sulfates regarding their applications are solubility (e.g. in water), rheological behavior, different interaction with low or high molecular cations, thermo reversible gel formation, enzymatic degradability, anticoagulant and antiviral activity. In C6‐position substituted cellulose sulfates can be synthesized in principle by acetosulfation. The acetosulfation is a quasi‐homogeneous synthesis proceeding under gradually dissolution of the cellulose by using different reactivity of the primary and secondary OH‐groups as soon as converting cellulose acetate sulfates. After precipitation of the polymer the acetyl groups are cleaved in alkaline solution. The focus of our study was firstly the investigation of the acetosulfation in different polar aprotic solvents by various sulfating and acetylating agents. In general it should be investigated if C6 substituted cellulose sulfates can be obtained by acetosulfation with different solvents and agents. The products were characterized by 13C‐NMR and Raman spectroscopy.

Cellulose acetate is one of the most important esters of cellulose. Depending on the way it has been processed cellulose acetate can be used for great varies of applications (e.g. for films, membranes or fibers). The properties of the applied cellulose acetates are very important for these applications. A special field for using cellulose acetate is the synthesis of porous, spherical particles, so called cellulose beads. Different types of technical cellulose acetates were used and their ability to form such cellulose beads was characterized. First the different types of cellulose acetates were characterized by means of solubility; turbidity and degree of substitution. In addition the molar mass and the distribution of substituents along the polymeric chain were analyzed. Next, the cellulose beads were synthesized within an emulsion process using these different cellulose acetates. Then the properties (particle size, porosity, morphology) of the cellulose beads were determined. Finally, the relationship between the characteristic of cellulose acetates and properties of cellulose beads was investigated.

Reductive coupling reactions between 4‐[18F]fluoro‐benzaldehyde ([18F]1) and different alcohols by use of decaborane (B10H14) as reducing agent have the potential to synthesize 4‐[18F]fluoro‐benzylethers in one step. [18F]1 was synthesized from 4‐trimethylammonium benzaldehyde (triflate salt) via a standard fluorination procedure (K[18F]F/Kryptofix® 222) in dimethylformamide at 90°C for 25 min and purified by solid‐phase extraction. Subsequently, reductive etherifications of [18F]1 were performed as one‐step reactions with primary and secondary alcohols, mediated by B10H14 in acetonitrile at 60°C. Various 4‐[18F]fluorobenzyl ethers (6 examples are shown) were obtained within 1–2 h reaction time in decay‐corrected radiochemical yields of 12–45%. Copyright © 2006 John Wiley & Sons, Ltd.

Xylan is the predominant hemicellulose component in the residues of annual plants, e.g., in oat spelts xylan amounts to 35–40% of the total mass. For our investigation xylan was separated through alkaline extraction of oat spelts. Our aim was to synthesize water‐soluble hemicellulose derivatives from oat spelts xylan preferably under heterogeneous conditions. Esterification was used for derivatization. The synthesises were optimised by variation of the temperature, reaction time and the molar ratios to achieve complete solubility, with good reproducibility and in good yields. Other modification possibilities and application areas of xylan from oat spelts could be proved.

Abstract A Raman crystallinity index – XcRaman – characterizing the degree of crystallinity of partially crystalline cellulose I samples was created, utilizing the crystallinity dependence of CH2 bending modes. For calibration, physical mixtures containing different mass fractions of crystalline cellulose I and its amorphous form were prepared. Crystallinities from 0 to 60% were generated. Relative intensity ratios of the Raman lines I and I characterizing crystalline and amorphous parts of cellulose I correlated linearly with the mass fraction of crystalline cellulose I of the mixtures. XcRaman values of microcrystalline celluloses of different origins and varying degree of crystallinity correlated reasonably with results obtained from NMR spectroscopy (XcNMR values).

FT Raman spectroscopy and micro spectroscopy were used for the investigation of cellulose, cellulose derivatives and cellulosic plant fibres. Lattice structures of cellulose, polymorphic modifications I and II, as well as amorphous structure, were clearly identified by means of FT Raman vibrational spectra. Chemometric models were developed utilizing univariate calibration as well as methods of multivariate data analyses of FT Raman spectral data for the fast prediction of cellulose properties. Cellulose properties like the degree of crystallinity XcRaman, the degree of substitution DSCMC, DSACand cellulose reactivity were determined.

Molten inorganic salt hydrates are highly efficient solvents forcellulose. The carboxymethylation of the polymer dissolved in this new group ofcellulose solvents was investigated. The homogeneous carboxymethylation ofcellulose in molten LiClO4•3H2O using sodiummonochloroacetate in the presence of NaOH is possible. The formation of CMC wasconfirmed by FT- Raman spectroscopy. Structure analysis by means of HPLC afterchain degradation showed the formation of CMC with a DS of 2 after a shortreaction time of 4 h. The derivatives exhibit a statisticaldistribution of substituents along the polymer chain if prepared in moltenLiClO4•3H2O as solvent. A substituent distributioninthe order C-6 > C-2 ≈ C-3 for anhydroglucose units (AGU) was concludedfrom 1H-NMR measurements. The synthesis of CMC in the swellingmediumLiCl•xH2O (2 ≤ x ≤ 5) yields polymers with astatistical distribution of functional groups along the chain. The watercontentof the salt melts has a dramatic influence on the DSCMC.

The surface polarity of native celluloses has been investigated by the following solvatochromic dyes: dicyano-bis (1,10)-phenanthroline iron (II) Fe(phen)2 (CN)2 (1), bis(4-N,N-dimethylamino)-benzophenone (2), and cou-marine 153 (3). Linear Solvation Energy (LSE) relationships and the UV/Vis data have been used to characterize the surface polarity of different native cellulose batches in terms of the empirical Kamlet–Taft polarity parameters α (hydrogen bond acidity), β (hydrogen bond basicity), and π * (dipolarity/polarizability). α, β, π *and calculated Reichardt's E T (30) values are reported for various native and regenerated cellulose samples with different degrees of crystallinity. The degree of crystallinity of the cellulose samples has been determined by X-ray. The microcrystalline environment of cellulose can be exactly parameterized in terms of the α, β and π *values. It shows a fairly strong acidity α and a low dipolarity/polarizability. For the amorphous sections smaller α and larger π * values are observed. The correspondence of the empirical polarity parameters determined has been discussed in relation to results from pyrene fluorescence and zetapotential measurements.

Molten salt hydrates proved to be alternative solvents to cellulose. Toinvestigate the reasons for this dissolving ability, information about thesolvent–cellulose interactions is essential. As well as 13CHR NMR, 7Li NMR was used to obtain further insight into thisproblem.After comparing several molten salt hydrates, the 7Li NMR spectrarevealed a smaller shielding of the lithium cation for not dissolving than fordissolving and swelling cellulose systems. In most solvent systems theshieldingat the 7Li nuclei increases with the cellulose concentration. 2D7Li-1H HOESY NMR was successfully applied to verify thepresence of cellobiose, used as a model compound for cellulose, in the firstco-ordination sphere of the lithium cation.

This is a report of the combined use of NIR FT Raman spectroscopy and X-ray diffraction measurements (WAXS) to investigate the polymorphic transformation of cellulose I into cellulose II. For this reason samples of cellulose I were swelled in different concentrations of NaOH and dissolved in different molten inorganic salts hydrates (LiCl·2ZnCl2·6H2O, LiClO4·3H2O, LiSCN·2,5H2O and ZnCl2·4H2O). NIR FT Raman spectra of the alkali treated samples were recorded. They characterize the pure modifications cellulose I and II as well as mixtures of the two polymorphic phases. The results of the Raman measurements were confirmed by X-ray scattering. The paper demonstrates that FT Raman vibrational spectroscopy is a powerful, rapid analytical method which may be used to follow the polymorphic transformation of cellulose I into cellulose II.

The behavior of cellulose in molten salt hydrates, e. g., LiClO4*3 H2O, ZnCl2*4 H2O, LiCl*5 H2O and mixtures of thiocyanates was investigated. Melts, which give rise to a swelling or dissolution of the cellulose were the focus of interest. The melt composition and species, the water amount and the structure of the coordination sphere of the cation of the molten salt hydrate as well as the acidity influence the solubility of the cellulose in molten salt systems. The interactions between cellulose and species of the melts were determined by solution state ¹³C NMR measurements at temperatures between 65°C and 140°C. Each regenerated cellulose showed other but specific properties which were characterized by wide angle X-ray Scattering (WAXS), solid-state NMR (¹³C CP/MAS NMR), molecular weight distribution, surface-area determinations and scanning electron microscopy (SEM).

The robust thermoresponsive and bioactive surfaces for tissue engineering by combining poly-N-isopropylacrylamide (PNIPAM) and cellulose sulfate (CS) remain highly in demand but not yet realized. Herein, PNIPAM-grafted cellulose sulfates (PCSs) with diverse degrees of substitution ascribed to sulfate groups (DSS) are synthesized for the first time. Higher sulfated PCS2 generally forms larger aggregates than lower sulfated PCS1 at their cloud point temperatures (TCP) of around 33 °C, whereas PCS1 leads to larger aggregates at body temperature (37 °C). Via the layer-by-layer (LbL) technique, biocompatible polyelectrolyte multilayers (PEMs) composed of PCSs as polyanions in combination with poly-l-lysine (PLL) or quaternized chitosan (QCHI) as polycations were fabricated. The resulting surfaces contained a more intermingled structure of polyanions with both polycations, while higher sulfated cellulose derivatives (CS2 and PCS2) displayed greater stability. Studies on toxicity and biocompatibility of PEM using 3T3 mouse fibroblasts showed a lower cytotoxicity of PEM with PCS2 and CS2 than PCS1 and CS1. Furthermore, the PEM using PCS2 particularly in combination with QCHI demonstrated excellent biocompatibility that is promising for new bioactive, thermoresponsive coatings on biomaterials and substrata for culturing adhesion-dependent cells.