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A crucial requirement for most engineering materials is the excellent balance of strength and toughness. By mimicking the hybrid hierarchical structure in nacre, a kind of nacre-like paper based on binary hybrid graphene oxide (GO)/sodium alginate (SA) building blocks has been successfully fabricated. Systematic evaluation for the mechanical property in different (dry/wet) environment/after thermal annealing shows a perfect combination of high strength and toughness. Both of the parameters are nearly many-times higher than those of similar materials because of the synergistic strengthening/toughening enhancement from the binary GO/SA hybrids. The successful fabrication route offers an excellent approach to design advanced strong integrated nacre-like composite materials, which can be applied in tissue engineering, protection, aerospace, and permeable membranes for separation and delivery.

Low-temperature, solution-based self-assembly of vanadia nanofibers yields a free-standing, ceramic paper with an outstanding combination of high strength, stiffness, and macroscopic flexibility. Its excellent mechanical performance results from a brick-and-mortar like architecture, which combines strong covalent bonding within the single-crystalline nanofibers with an intricate hydrogen bonding network between them.

In this work, we prepare cellulose nanopapers of high mechanical performance and with the electrical conductivity of a semiconductor. Cellulose nanofibers (CNF) from bleached softwood pulp were coated with polypyrrole (PPy) via in situ chemical polymerization, in presence of iron chloride (III) as oxidant agent. The structure and morphology of nanopapers were studied, as well as their thermal, mechanical and conductive properties. Nanopaper from pure CNF exhibited a very high tensile response (224 MPa tensile strength and 14.5 GPa elastic modulus). The addition of up to maximum 20% of polypyrrole gave CNF/PPy nanopapers of high flexibility and still good mechanical properties (94 MPa strength and 8.8 GPa modulus). The electrical conductivity of the resulting CNF/PPy nanopaper was of 5.2 10 −2 S cm −1 , with a specific capacitance of 7.4 F g −1 . The final materials are strong and conductive nanopapers that can find application as biodegradable flexible thin-film transistor (TFT) or as flexible biosensor.

Modification of properties of old newspaper (ONP) deinked pulp with laccase and histidine was investigated. It was found that the optimum conditions for laccase–histidine treatment were: the concentration of laccase 0.9 U/g dry pulp, the concentration of histidine 1% relative to the dry pulp, room temperature, reaction time 1.5 h, pH 7, the pulp consistency 5% and O2 atmosphere. The results also showed that, in the optimum conditions, compared to the control pulp, the wet tensile strength, the carboxyl group content and water retention value of ONP treated with laccase and histidine were increased by 55.1%, 39.1% and 45.7%, respectively. Moreover, environmental scanning microscope images showed that more collapse and more fibrillation were observed on the laccase–histidine-treated fiber surface than the control samples, which led to form better bonding between fibers in handsheets resulting in the increase of the paper strength of laccase–histidine-treated ONP pulp.

The effects of neodymium:yttrium-aluminium-garnet (Nd:YAG) laser and silicon carbide (SiC) paper on the surface micro-topography of titanium-6 aluminium-4 vanadium (Ti6Al4V) alloy were examined in relation to the response of bone cells. The study was performed in three distinct stages: (1) after surface treatment of samples by laser and SiC paper, the surface hardness, surface roughness, corrosion resistance and surface tension were evaluated; (2) the growth of mouse connective tissue fibroblast cells (L-929) on untreated and treated samples was assessed in vitro; (3) the response of goat osteoblast cells to untreated and treated implanted samples was assessed in vivo. The surface roughness varied between 7 +/- 0.02 for laser-treated samples (LTSs) at 140 J cm(-2) and 21.8 +/- 0.05 for mechanically treated samples (MTSs). The surface hardness was found to vary from 377 Vickers hardness number (VHN) for MTSs to 850 VHN for LTSs. A corrosion potential of -0.21V was achieved for the LTSs compared with -0.51V for the MTSs. The LTSs exhibited a more hydrophilic behaviour (i.e. wettability) than did the MTSs. No cytotoxicity effect, unlike for the MTSs, was observed for the LTSs. The results of in vivo tests indicated longitudinal growth of osteoblast cells along the grooves on the samples formed by the SiC paper, and multidirectional spreading of the cells on the LTSs.

Significant enhancement in mechanical stiffness (10-200%) and fracture strength (approximately 50%) of graphene oxide paper, a novel paperlike material made from individual graphene oxide sheets, can be achieved upon modification with a small amount (less than 1 wt %) of Mg(2+) and Ca(2+). These results can be readily rationalized in terms of the chemical interactions between the functional groups of the graphene oxide sheets and the divalent metals ions. While oxygen functional groups on the basal planes of the sheets and the carboxylate groups on the edges can both bond to Mg(2+) and Ca(2+), the main contribution to mechanical enhancement of the paper comes from the latter.

The removal of old glue from paper artworks is of paramount importance for the preservation of its integrity during the restoration process. Wet cleaning is one of the traditional methods, although it may cause damages on artworks. In this work, an advantageous alternative method, based on the use of a rigid hydrogel, for a simple and localized removal of starch paste from paper supports is presented. The use of an appropriate hydrogel allows to overcome many of the problems faced by restorers minimizing damages, through a controlled release of water to the artwork, and a simple and not invasive application and removal. At the same time, the specific and targeted enzyme activity leads to a significant reduction in the application time of the cleaning procedure. In this context, experiments were carried out applying Gellan hydrogel carrying α-amylase enzyme on several paper samples soiled with starch paste. To assess the cleaning efficacy of the proposed hydrogel, we have used a multidisciplinary approach, by means of spectroscopic techniques, scanning electron microscopy, chromatographic analysis, and pH investigations.

The objective of the study was to improve fruit quality, including health compounds, by improving light utilization for fruit crops under hail net. Four reflective mulches including plastics such as Extenday® and a bio-degradable paper were spread in the alleyways of a cv. 'Gala Mondial' apple orchard on 10 August 2010 5 weeks before anticipated harvest.Reflective mulch affected neither fruit firmness nor sugar, but accelerated starch breakdown, indicative of riper fruits (smaller Streif index), compared with the uncovered grass alleyway (control). Reflective mulches also improved fruit quality such as red coloration of cv. 'Gala Mondial' apples. This was due to significantly enhanced flavonoids and anthocyanins. Flavonoids increased up to 52.4% in the Extenday® treatment (29.2 nmol cm(-2) in the grass control versus 44.5 nmol cm(-2) fruit peel with reflective mulch). Similarly, reflective mulch improved anthocyanin content in cv. 'Gala Mondial' peel up to 66% compared to grass control (14.5 nmol cm(-2) in control fruit versus 24.1 nmol cm(-2) with reflective mulch). The reflective mulch did not affect chlorophyll and carotenoid content in the 'Gala' fruit peel.Overall, the application of reflective mulches improved fruit quality in terms of better coloration and health compounds and accelerated ripening, leading to higher market value.

In this study, we investigated the statistical relationship between nanostructure variations of carbon nanotube buckypaper-polymer (BPP) composites and their resulting elastic properties. A statistical simulation was developed to predict the elastic properties of a single-layer BPP lamina and extrapolated to the resultant bulk composite part. The stochastic characteristics of BPP composite nanostructure were quantified from experimental observations and used to generate the input for each simulation set performed. The Mori-Tanaka method was used to calculate the stiffness tensor within the buckypaper-polymer region, and a Monte-Carlo simulation was applied to generate the probability distribution for the effective stiffness tensor within each BPP lamina. Classical laminate theory was then employed to predict the effective elastic response for a multi-layered BPP composite laminate. The theoretical predictions were compared with experimental data, and the resulting trends for the effective tensile modulus between experimental and theoretical corresponded well with each other.

The paper describes results obtained in the development of a previous research. We study here, in fast firing, the sintering behaviour and measure some properties of tiles containing a mixture of 60 wt% of paper mill sludge and 40 wt% of glass cullet. The behaviour of this material is compared to those displayed by materials obtained by the same mixture added with 10, 20 and 30 wt% of a natural red clay. In parallel, the same properties are measured also on a reference blend, which is presently used to produce commercial tiles. We show that powders containing 60 wt% of paper sludge and 40 wt% of glass cullet to which 30 wt% of clay is added give rise to materials that display a stable sintering process and have good hardness and strength and therefore could be used for the industrial production of tiles.

Introduction: The amelogenin proteins secreted by ameloblasts during dental enamel development are required for normal enamel structure. Amelx null (KO) mice have hypoplastic, disorganized enamel similar to that of human patients with mutations in the AMELX gene, and provide a model system for studies of the enamel defect amelogenesis imperfecta. Because many amelogenin proteins are present in developing enamel due to RNA alternative splicing and proteolytic processing, understanding the function of individual amelogenins has been challenging. Purpose: Our objective was to better understand the role of LRAP, a 59 amino acid leucine-rich amelogenin peptide, in the development of enamel. Approach: Teeth from transgenic mice that express LRAP under control of the Amelx regulatory regions were analyzed for mechanical properties, and transgenic males were mated with female KO mice. Male offspring with a null background that were transgene positive or transgene negative were compared to determine phenotypic differences using microcomputed tomography (microCT) and scanning electron microscopy (SEM). Results: Nanoindentation revealed no differences between LRAP transgenic and wild-type murine enamel. Using microCT, LRAPKO enamel volume and density measurements were similar to those from KO mice. However, in etched samples examined by SEM, the organization of the enamel rod pattern was altered by the presence of the LRAP transgene. Conclusions: The presence of LRAP leads to changes in enamel appearance compared to enamel from KO mice. Expression of a combination of amelogenin transgenes in KO mice may lead to rescue of the individual characteristics of normal enamel.