Search

Enzymatic polymerization of lignosulfonate (LS) has a high potential for various applications ranging from coatings to adhesives. Here, the effect of different ions in low concentrations on enzymatic polymerization of LS was investigated, including salt solutions consisting of mono‐ and dicarboxylic acids, sulfate, phosphate and chloride with sodium as counter ion. LS polymerization was followed by viscometry and size exclusion (SEC) chromatography. Interestingly, there was only a small effect of ions on the activity of the laccase on standard substrate ABTS, while the effect on polymerization of LS was substantially different. The presence of acetate led to a 39 % higher degree of polymerization (DP) for LS. Small angle X‐ray scattering (SAXS) revealed that the structure of the enzyme was largely unaffected by the ions, while the determination of the zeta potential showed that those ions conveying higher negative surface charges onto LS particles showed lower DPs, than those not affecting the surface charge. Further, electron paramagnetic resonance (EPR) spectroscopy showed 5‐times higher intensity in phenoxyl radicals for the monovalent ions compared to the divalent ones. It was concluded that the DPs of LS could be tuned in the presence of certain ions, by facilitating the interaction between the laccase substrate‐binding site and the LS molecules. [ABSTRACT FROM AUTHOR]

Background: Glyphosate (GLP) is a widely used herbicide with possible adverse effects on human health and the environment. In soils, GLP strongly adsorbs on clay‐sized minerals, depending on pH, the amount of organic carbon, as well as the contents and properties of Al and Fe oxyhydroxides and clay minerals. Many clay‐sized minerals have already been investigated regarding GLP adsorption behavior, but information on minerals commonly found in volcanic soils is still lacking. Aim: The aim of this study was to investigate for the first time the pH‐dependent adsorption of GLP on allophane and halloysite, typical minerals found in volcanic soils. Methods: GLP adsorption was studied in batch experiments at three pH values (5, 6, and 7). Synthetic allophanes with two different initial Al:Si ratios (1.4 and 1.8) and a halloysite were used as adsorbents. Results: The adsorption capacity (AC) increased with rising Al:Si ratio and decreasing pH. The AC of allophane was significantly higher than that of halloysite. GLP adsorption on allophane was larger than that reported for other clay minerals and Al and Fe oxyhydroxides, especially at low pH. The AC of halloysite was higher than reported for most other clay minerals. Conclusion: Different mineral formation pathways in volcanic soils, notably the formation of halloysite versus allophanes, strongly affect the soils' retention capacity for GLP. The high AC of allophanes may induce the low mobility of GLP in allophane‐containing soils. Long‐term use of GLP may accumulate the herbicide in these soils with potential effects on biodiversity and ecosystem services. [ABSTRACT FROM AUTHOR]

Nano-reinforcements in carbon fibre-reinforced polymer (CFRP) have proven to enhance the mechanical properties considering quasi-static, as well as fatigue load and, are a promising option with regard to CFRP performance optimisation. While general knowledge about the nanofiller content and its influence in CFRP is well documented, the use of alignment techniques for a specific orientation of the nano-reinforcements is still insufficiently studied. In this work, the influence of oriented carbon nanofibres (CNF) on the mechanical properties of bidirectional CFRP is investigated. CFRP was produced CNF-reinforced with and without orientation using a hot press, where an electric field was applied during curing. The laminates were characterised with respect to dispersion quality, pore volume, quasi-static properties (tensile and bending tests) and dynamic properties (fatigue tests). Electrical resistance measurement was applied together with digital image correlation and in situ computed tomography to generate knowledge about the fatigue-related damage evolution and evaluate the sensors for viable use of condition monitoring. Results show that the orientation of CNF has a significant impact on both quasi-static and fatigue properties, increasing the strength while reducing and slowing down the introduced damage. Orientation of nanofillers thus shows large optimization potential of mechanical properties of CFRP components. [ABSTRACT FROM AUTHOR]

Microparticles made from hydrogenated sunflower oil without essential oil and with different essential oil concentrations (75–300 g/kg; g of essential oil per kg of microparticles) were stored for 1 or 2 months at 25 or 37 °C. Before and after storage the essential oil concentration, flowability, optical appearance, melting behaviour and crystalline structure of the microparticles were investigated. Essential oil recovery, melting behaviour and crystalline structure were identical for the essential oil containing microparticles and were not affected during storage. The surface structure of the microparticles varied with their essential oil concentration. While the particles containing 75 g/kg essential oil were covered by erect fat crystals, those with 225 g/kg and higher were mostly smooth with some round shaped dumps. However, the surface of all essential oil containing microparticle batches had reached their final stage after production already and did not change during storage. Microparticles without essential oil presented two melting peaks; all microparticle batches with essential oil had one peak. Peaks in the X-ray scattering powder diffraction signal of the essential oil-free microparticles after production can be associated with the α-form of the hydrogenated vegetable oil. During storage, a conversion of the α-form to the stable β-form was observed. Microscopy showed that these microparticles also developed strong fat crystals throughout storage. The triglycerides in microparticles with essential oil seem to directly take on the stable β-form. The formation of robust microparticle agglomerates during storage was prevalently observed for the fat crystal forming product batches, meaning the products without or with low essential oil concentration. [ABSTRACT FROM AUTHOR]

Protein‐A chromatography is the most widely used chromatography step in downstream processing of antibodies. A deeper understanding of the influence of the surface topology on a molecular/nanoscale level on adsorption is essential for further improvement. It is not clear if the binding is homogenous throughout the entire bead network. We followed the protein absorption process and observed the formation of a protein layer on fibers of chromatography resin in a time‐resolved manner in nanoscale. To characterize the changes in the antibody‐protein‐A ligand complex, small angle X‐ray scattering was employed using a miniaturized X‐ray‐transparent chromatography column packed with a MabSelect SuRe resin. Antibody‐free MabSelect SuRe resin fiber had an average radius of 12 nm and the protein layer thickness resulting from antibody adsorption was 5.5 and 10.4 nm for fiber and junctions, respectively under applied native conditions. We hypothesize that an average of 1.2 antibodies were adsorbed per protein‐A ligand tetramer bound to the outermost units. In contrast to previous studies, it was therefore possible for the first time to directly correlate the nanostructure changes inside the column, which is otherwise a black box, with the adsorption and elution process. [ABSTRACT FROM AUTHOR]

Microparticles with different essential oil concentrations 0, 75, 150, 225 and 300 gkg−1, (g of essential oil per kg of microparticles), were produced by dispersing the essential oils within a hydrogenated vegetable fat matrix and forming spherical solid particles by spray-chilling. Size distribution, flowability, surface structure, essential oil recovery, melting properties and crystallinity of the microparticles were determined. With over 225 gkg−1 essential oil the microparticle surface became stickier, their flowability was reduced and the size distribution broadened. Gas chromatography showed that the essential oil recovery was always above 85% v/v. The surface structure of the microparticles was strongly affected by the essential oil concentration being smooth (225 gkg−1), comprising round-shaped dumps (300 gkg−1) or showing fat blooming (0, 75, 150 gkg−1). With essential oil, the formation of the β-polymorphic form of the triglycerides was supported leading to changes in the melting behaviour and the crystalline structure. [ABSTRACT FROM AUTHOR]

Die herkömmliche Bestimmung der Kristallvorzugsorientierung (kristallographische Textur) beruht auf Röntgenbeugung mit Flächendetektoren und 2D ‐ Daten. Echte, ortsaufgelöste 3D ‐ Informationen erfordern eine Probendrehung im Strahl. Dabei wird das beleuchtete Volumen ständig verändert und das Streusignal verschmiert, was die Bestimmung komplexer Strukturen verhindert. Diese Einschränkung lässt sich mit energieauflösender Laue ‐ Beugung umgehen. Es wurde eine Methode entwickelt, um einen großen Teil des reziproken Raums abzudecken und aus der Energie der Röntgenphotonen die dritte Raumdimension zu errechnen. Das Verfahren wurde auf Kohlenstofffasern und Hummerpanzer, als Beispiel für biomineralisiertes Gewebe, angewendet. Das besondere Potenzial dieser Methode liegt darin, dass sie nur eine einzige Messung erfordert, sowie am direkten Erfassen von 3D ‐ Informationen ohne Vorwissen über die Probe. Das Verfahren ermöglicht daher das Abrastern großer Proben mit komplexer Struktur und eröffnet die konzeptuelle Möglichkeit, Texturänderungen in situ zu verfolgen, z. B. während Kristallisationsvorgängen. Texturverarbeitungs ‐ Programm: Eine neue Methode zur Bestimmung der kristallographischen Textur auf Basis energieauflösender Laue ‐ Beugung nutzt die Krümmung der Ewald ‐ Kugel, um 3D ‐ Informationen ohne Probenrotation zu erhalten, wodurch eine vorher unerreichte räumliche Auflösung möglich wird. Das Prinzip wird anhand eines komplexen Kohlenstofffasersystems und eines biomineralisierten Hummerpanzers demonstriert. [ABSTRACT FROM AUTHOR]

Conventional analysis of the preferred orientation of crystallites (crystallographic texture) involves X-ray diffraction with area detectors and 2D data output. True 3D, spatially resolved information requires sample rotation in the beam, thus changing the probed volume, which introduces signal smearing and precludes the scanning of complex structures. This obstacle has been overcome by energy-dispersive Laue diffraction. A method has been devised to reach a large portion of reciprocal space and translate the X-ray photon energy into the missing third dimension of space. Carbon fibers and lobster exoskeleton as examples of biomineralized tissue have been analyzed. The major potential of this method lies in its 'one-shot' nature and the direct 3D information requiring no previous knowledge of the sample. It allows the texture of large samples with complex substructures to be scanned and opens up the conceptual possibility of following texture changes in situ, for example, during crystallization. [ABSTRACT FROM AUTHOR]

Carbon microparticles were produced from organosolv lignin at 2000 °C under argon atmosphere following oxidative thermostabilisation at 250 °C. Scanning electron microscopy, X-ray diffraction, small-angle X-ray scattering, and electro-conductivity measurements revealed that the obtained particles were electrically conductive and were composed of large graphitic domains. Poly(lactic acid) filled with various amounts of lignin-derived microparticles showed higher tensile stiffness increasing with particle load, whereas strength and extensibility decreased. Electric conductivity was measured at filler loads equal to and greater than 25% w/w. [ABSTRACT FROM AUTHOR]

Abstract: The development of the structure of silica/alumina gels was investigated by small angle X-ray scattering (SAXS) through all stages of the preparation process, that is gelation, aging, drying and calcination. Two series of gels were compared; the first was prepared from a single-source precursor, obtained by reaction of 3-oxoethyl-6-trimethoxysilyl-hexan-2-one (OTH-H) with Al(O s Bu)3. The gels of the second series were prepared from the same precursors, but under conditions where hydrodeacylation of OTH-H occurs. It turned out that both series showed a similar structural development of the gels. Immediately after the start of the reaction small primary particles are formed, the size of which (r =0.7±0.1nm) remains constant through the gelation and aging process. In some samples, Si(OEt)4 was added as an additional source for Si/O which was incorporated between the primary particles. Condensation proceeds by a slower aggregation of the primary particles, which initially form a rather open network. This network densifies during aging and drying. [Copyright &y& Elsevier]

Dispersion of carbon nanotubes and carbon nanofibers is a crucial processing step in the production of polymer-based nanocomposites and poses a great challenge due to the tendency of these nanofillers to agglomerate. Besides the well-established three-roll mill, the ultrasonic dispersion process is one of the most often used methods. It is fast, easy to implement, and obtains considerably good results. Nevertheless, damage to the nanofibers due to cavitation may lead to shortening and changes in the surface of the nanofillers. The proper application of the sonicator to limit damage and at the same time enable high dispersion quality needs dedicated knowledge of the damage mechanisms and characterization methods for monitoring nano-particles during and after sonication. This study gives an overview of these methods and indicates parameters to be considered in this respect. Sonication energy rather than sonication time is a key factor to control shortening. It seems likely that lower powers that are induced by a broader tip or plate sonicators at a longer running time would allow for proper dispersions, while minimizing damage. [ABSTRACT FROM AUTHOR]

Due to recent changing climate conditions and glazing of building facades, a rapid increase in the requirement of cooling systems can be observed. Still the main energy source for cooling are fossil fuels. In this article we report on a fully integrated approach of running a heat pump for actively cooling a test room by electric energy, generated by facade integrated photovoltaic modules, the "COOLSKIN" system. Photovoltaic facades are emission free in the operation phase, efficiently utilize otherwise unused surfaces, and portray a favorable method in terms of construction physics and the architectural design of buildings. Compared to existing systems, COOLSKIN is an entirely autonomous system where every component is located inside the facade structure which introduces a high level of plug and play character. In this article the analysis of the electric performance of the COOLSKIN system with respect to its operation under different environmental conditions is presented. The over all system efficiency was determined with 73.9%, compared to a simulated efficiency (PV*SOL) of 68.8%, and to the theoretically expected value of 85%. The system behavior is evaluated depending on photovoltaic output and the cooling demand. The analysis shows that a considerable amount of cooling demand could be decentrally fulfilled with photovoltaic energy, but environmental conditions as well as system layout have a considerable impact on system performance. [ABSTRACT FROM AUTHOR]

Application of low-cost carbon black from lignin highly depends on the materials properties, which might by determined by raw material and processing conditions. Four different technical lignins were subjected to thermostabilization followed by stepwise heat treatment up to a temperature of 2000 °C in order to obtain micro-sized carbon particles. The development of the pore structure, graphitization and inner surfaces were investigated by X-ray scattering complemented by scanning electron microscopy and FTIR spectroscopy. Lignosulfonate-based carbons exhibit a complex pore structure with nanopores and mesopores that evolve by heat treatment. Organosolv, kraft and soda lignin-based samples exhibit distinct pores growing steadily with heat treatment temperature. All carbons exhibit increasing pore size of about 0.5–2 nm and increasing inner surface, with a strong increase between 1200 °C and 1600 °C. The chemistry and bonding nature shifts from basic organic material towards pure graphite. The crystallite size was found to increase with the increasing degree of graphitization. Heat treatment of just 1600 °C might be sufficient for many applications, allowing to reduce production energy while maintaining materials properties. [ABSTRACT FROM AUTHOR]

Nanostructured metal assemblies on thin and ultrathin polymeric films enable state of the art technologies and have further potential in diverse fields. Rational design of the structure–function relationship is of critical importance but aggravated by the scarcity of systematic studies. Here, we studied the influence of the interplay between metal and polymer surface free energy and reactivity on the evolution of electric conductivity and the resulting morphologies. In situ resistance measurements during sputter deposition of Ag, Au, Cu and Ni films on ultrathin reticulated polymer films collectively reveal metal–insulator transitions characteristic for Volmer–Weber growth. The different onsets of percolation correlate with interfacial energy and energy of adhesion weakly but as expected from ordinary wetting theory. A more pronounced trend of lower percolation thickness for more reactive metals falls in line with reported correlations. Ex situ grazing incidence small angle X-ray scattering experiments were performed at various thicknesses to gain an insight into cluster and film morphology evolution. A novel approach to interpret the scattering data is used where simulated pair distance distributions of arbitrary shapes and arrangements can be fitted to experiments. Detailed approximations of cluster structures could be inferred and are discussed in view of the established parameters describing film growth behavior. [ABSTRACT FROM AUTHOR]

Dispersion of carbon nanotubes and carbon nanofibers is a crucial processing step in the production of polymer-based nanocomposites and poses a great challenge due to the tendency of nanofillers to agglomerate. One of the most effective methods for dispersion is the use of a three-roll mill, which is a well-established method and results in agglomerates below 5 µm. Nevertheless, this process is time-consuming and thus a limiting factor for industrial applications. Our aim was to establish an easy and efficient ultrasonic dispersion process, characterize the dispersion parameters, and compare both methods, ultrasonication and the three-roll mill. We applied rheological tests and analyzed the agglomerate sizes by an image fit of the microscopy images. All these analyses combined deliver a valuable set of information about the dispersion's quality and, therefore, allows the improvement and further adaptation of the dispersion process. [ABSTRACT FROM AUTHOR]

Multiscale ceramic-organic supercrystalline nanocomposites with two levels of hierarchy have been developed via self-assembly with tailored content of the organic phase. These nanocomposites consist of organically functionalized ceramic nanoparticles forming supercrystalline micron-sized grains, which are in turn embedded in an organic-rich matrix. By applying an additional heat treatment step at mild temperatures (250–350 °C), the mechanical properties of the hierarchical nanocomposites are here enhanced. The heat treatment leads to partial removal and crosslinking of the organic phase, minimizing the volume occupied by the nanocomposites' soft phase and triggering the formation of covalent bonds through the organic ligands interfacing the ceramic nanoparticles. Elastic modulus and hardness up to 45 and 2.5 GPa are attained, while the hierarchical microstructure is preserved. The presence of an organic phase between the supercrystalline grains provides a toughening effect, by curbing indentation-induced cracks. A mapping of the nanocomposites' mechanical properties reveals the presence of multiple microstructural features and how they evolve with heat treatment temperature. A comparison with non-hierarchical, homogeneous supercrystalline nanocomposites with lower organic content confirms how the hierarchy-inducing organic excess results in toughening, while maintaining the beneficial effects of crosslinking on the materials' stiffness and hardness. [ABSTRACT FROM AUTHOR]

Yak belly hair was proposed as a cheap substitute for human hair for the development of hair dyes, as its chemical composition closely resembles human hair in Raman spectroscopy. The absence of melanin in yak belly hair also leads to a strong reduction of fluorescence in Raman measurements, which is advantageous for the investigation of the effectivity of hair dyes. To assess the suitability for replacing human hair, we analyzed similarities and differences of both hair types with a variety of methods: Raman spectroscopy, to obtain molecular information; small-angle X-ray scattering to determine the nanostructure, such as intermediate filament distance, distance of lipid layers and nanoporosity; optical and scanning electron microscopy of surfaces and cross sections to determine the porosity at the microstructural level; and density measurements and tensile tests to determine the macroscopic structure, macroporosity and mechanical properties. Both types of hair are similar on a molecular scale, but differ on other length scales: yak belly hair has a smaller intermediate filament distance on the nanoscale. Most striking is a higher porosity of yak belly hair on all hierarchical levels, and a lower Young's modulus on the macroscale. In addition to the higher porosity, yak belly hair has fewer overlapping scales of keratin, which further eases the uptake of coloring. This makes, on the other hand, a comparison of coloring processes difficult, and limits the usefulness of yak belly hair as a substitute for human hair. [ABSTRACT FROM AUTHOR]

Structural and chemical deterioration and its impact on cell wall mechanics were investigated for visually intact cell walls (VICWs) in waterlogged archaeological wood (WAW). Cell wall mechanical properties were examined by nanoindentation without prior embedding. WAW showed more than 25% decrease of both hardness and elastic modulus. Changes of cell wall composition, cellulose crystallite structure and porosity were investigated by ATR-FTIR imaging, Raman imaging, wet chemistry, 13C-solid state NMR, pyrolysis-GC/MS, wide angle X-ray scattering, and N2 nitrogen adsorption. VICWs in WAW possessed a cleavage of carboxyl in side chains of xylan, a serious loss of polysaccharides, and a partial breakage of β-O-4 interlinks in lignin. This was accompanied by a higher amount of mesopores in cell walls. Even VICWs in WAW were severely deteriorated at the nanoscale with impact on mechanics, which has strong implications for the conservation of archaeological shipwrecks. [ABSTRACT FROM AUTHOR]

Carbon particles were produced from kraft lignin through carbonization of perfectly spherical, sub-micron beads obtained by aerosol flow. The structure of the resulting carbon particles was elucidated and compared to that derived from commercially available technical lignin powder, which is undefined in geometry. In addition to the smaller diameters of the lignin beads (<1 µm) compared to those of the lignin powder (100 µm), the former displayed a slightly higher structural order as revealed by X-ray diffraction and Raman spectroscopy. With regard to potential application in composite structures, the sub-micron carbon beads were clearly advantageous as a filler of cellulose nanopapers, which displayed better mechanical performance but with limited electrical conductivity. Compression sensing was achieved for this nanocomposite system. [ABSTRACT FROM AUTHOR]

Carbon nanotubes (CNT) provide an outstanding property spectrum which can be used to improve a wide range of materials. However, the transfer of properties from the nanoscale to a macroscopic material is a limiting factor. Different approaches of functionalizing the surface of a CNT can improve the interaction with the surrounding matrix but is connected to difficult and expensive treatments, which are usually inconvenient for industrial applications. Here, a simple and eco-friendly method is presented for the oxidation of CNT, where hydrogen peroxide (H2O2) is the only chemical needed and no toxic emissions are released. Also, the extensive step of the incorporation of CNT to an epoxy matrix is simplified to an ultrasonic dispersion in the liquid hardener component. The effectiveness is proven by mechanical tests of produced CNT/CFRP and compared to a conventional processing route. The combination of those simple and cost efficient strategies can be utilized to produce multiscale composites with improved mechanical performance in an ecological and economical way. [ABSTRACT FROM AUTHOR]

Kristallographische Textur. H. C. Lichtenegger et al. beschreiben in der Zuschrift auf S. 12376 ff. eine Methode zur Bestimmung der kristallographischen Textur auf der Grundlage der energiedispersiven Laue ‐ Beugung. Ohne Drehung der Probe können 3D ‐ Informationen erhalten werden. [ABSTRACT FROM AUTHOR]

The cover page of the journal "Angewandte Chemie International Edition" is presented, which offers information on the article "Photon Energy Becomes the Third Dimension in Crystallographic Texture Analysis," by Harald Rennhofer and others.

Biochar (BC) is increasingly used as soil amendment; however, its stability and alteration in the soil environment are still unclear. Here, we investigated BC decomposition and changes of BC characteristics during a long-term incubation experiment. 13 C-depleted BCs were incubated for two years in an acidic Planosol and a calcareous Chernozem, respectively. BC decomposition inferred from the C isotope signature of the incubated materials was marginal. Yet, small angle X-ray scattering showed that the surface roughness of the BCs increased over time. Mid-infrared spectra indicated changes in the BCs' molecular characteristics upon aging. There was an overall increase of infrared bands assigned to H- and O-containing functional groups, especially carboxylic groups. Contact angle measurements revealed that the hydrophobic surfaces of freshly produced BCs became more hydrophilic during soil incubation. Our results suggest that BC aging is strongly influenced by soil traits. In the more acidic Planosol, these aging processes were accelerated. [ABSTRACT FROM AUTHOR]

• Nanostructure of mineral in sclerosing osteosarcoma differs from healthy tissue. • Smaller mineral platelets in spite of higher mineralization indicate high turnover. • Crystal lattice distortions of bone mineral suggest different ion substitution. • Synchrotron-microbeam large-area fast scanning provides detailed microscope images. Osteosarcoma is the most common primary bone cancer type in humans. It is predominantly found in young individuals, with a second peak later in life. The tumour is formed by malignant osteoblasts and consists of collagenous, sometimes also mineralized, bone matrix. While the morphology of osteosarcoma has been well studied, there is virtually no information about the nanostructure of the tumour and changes in mineralization on the nanoscale level. In the present paper, human bone tissue inside, next to and remote from a sclerosing osteosarcoma was studied with small angle x-ray scattering, x-ray diffraction and electron microscopy. Quantitative evaluation of nanostructure parameters was combined with high resolution, large area mapping to obtain microscopic images with nanostructure parameter contrast. It was found that the tumour regions were characterized by a notable reduction in mineral particle size, while the mineral content was even higher than that in normal bone. Furthermore, the normal preferential orientation of mineral particles along the longitudinal direction of corticalis or trabeculae was largely suppressed. Also the bone mineral crystal structure was affected: severe crystal lattice distortions were detected in mineralized tumour tissue pointing to a different ion substitution of hydroxyl apatite in tumorous tissue than in healthy tissue. [ABSTRACT FROM AUTHOR]

Abstract Biochar (BC) is increasingly tested as a soil amendment for immobilization of heavy metals (HMs) and other pollutants. In our study, an acidic soil amended with wood chip-derived BC showed strongly enhanced Cu and Cd sorption after 15 months of aging under greenhouse conditions. X-ray absorption near edge structure suggested formation of Cu(OH) 2 and CuCO 3 and upon aging increasingly Cu sorption to the BC organic phase (from 9.2% to 40.7%) as main binding mechanisms of Cu on the BCs. In contrast, Cd was predominantly bound as CdCO 3 on the BCs even after 15 months (82.7%). We found indications by mid-infrared spectroscopy that the formation of organic functional groups plays a role for increased HM sorption on aged BCs. Yet, our data suggest that the accessibility of BC's pore network and reactive surfaces is likely to be the overriding factor responsible for aging-related changes in HM sorption capacity, rather than direct interactions of HMs with oxidized functional groups. We observed highly weathered BC surface structures with scanning electron microscopy along with strongly increased wettability of the BCs after 15 months of soil aging as indicated by a decrease of water contact angles (from 62.4° to 4.2°). Graphical abstract Image 1 Highlights • Soil aging of biochar increased Cu and Cd sorption capacity. • Increased access of dissolved metals to biochar pores upon aging. • Cu was increasingly sorbed to the biochar organic phase upon aging. • Cd was predominantly bound as CdCO 3 on the biochars even after aging. [ABSTRACT FROM AUTHOR]

Cutinases have shown potential for hydrolysis of the recalcitrant synthetic polymer polyethylene terephthalate (PET). We have shown previously that the rate of this hydrolysis can be enhanced by the addition of hydrophobins, small fungal proteins that can alter the physicochemical properties of surfaces. Here we have investigated whether the PET-hydrolyzing activity of a bacterial cutinase from Thermobifida cellulosilytica (Thc_Cut1) would be further enhanced by fusion to one of three Trichoderma hydrophobins, i.e., the class II hydrophobins HFB4 and HFB7 and the pseudo-class I hydrophobin HFB9b. The fusion enzymes exhibited decreased kcat values on soluble substrates (p-nitrophenyl acetate and p-nitrophenyl butyrate) and strongly decreased the hydrophilicity of glass but caused only small changes in the hydrophobicity of PET. When the enzyme was fused to HFB4 or HFB7, the hydrolysis of PET was enhanced>16-fold over the level with the free enzyme, while a mixture of the enzyme and the hydrophobins led only to a 4-fold increase at most. Fusion with the non-class II hydrophobin HFB9b did not increase the rate of hydrolysis over that of the enzyme-hydrophobin mixture, but HFB9b performed best when PET was preincubated with the hydrophobins before enzyme treatment. The pattern of hydrolysis by the fusion enzymes differed from that of Thc_Cut1 as the concentration of the product mono(2-hydroxyethyl) terephthalate relative to that of the main product, terephthalic acid, increased. Small-angle X-ray scattering (SAXS) analysis revealed an increased scattering contrast of the fusion proteins over that of the free proteins, suggesting a change in conformation or enhanced protein aggregation. Our data show that the level of hydrolysis of PET by cutinase can be significantly increased by fusion to hydrophobins. The data further suggest that this likely involves binding of the hydrophobins to the cutinase and changes in the conformation of its active center. [ABSTRACT FROM AUTHOR]

The promising applications of core-shell nanoparticles in the biological and medical field have been well investigated in recent years. One remaining challenge is the characterization of the structure of the hydrated polymer shell. Here we use small-angle X-ray scattering (SAXS) to investigate iron oxide core-poly(ethylene glycol) brush shell nanoparticles with extremely high polymer grafting density. It is shown that the shell density profile can be described by a scaling model that takes into account the locally very high grafting density near the core. A good fit to a constant density region followed by a star-polymer-like, monotonously decaying density profile is shown, which could help explain the unique colloidal properties of such densely grafted core-shell nanoparticles. SAXS experiments probing the thermally induced dehydration of the shell and the response to dilution confirmed that the observed features are associated with the brush and not attributed to structure factors from particle aggregates. We thereby demonstrate that the structure of monodisperse core-shell nanoparticles with dense solvated shells can be well studied with SAXS and that different density models can be distinguished from each other.