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UHPC has been developed in the Czech republic for about 15 years. The paper shows some of the new footbridges with the deck made of UHPC and then focuses on repair and strengthening of existing structures. Extensive experimental work was carried out as a basis for applications. Different loading situations were examined so that the structural performance in serviceability and in ultimate limit states was investigated. Experience from the construction of structures made of UHPC, from extensive experimental campaign, and from literature resulted in development of the Technical conditions for production of UHPC, design and execution and for reconstruction of structures with UHPC, which were approved by the Ministry of Transport in 2024. The document provides a possibility to apply UHPC also in structures of the transport infrastructure. Finally, example of application of UHPC in repair of a heavily loaded road bridge is introduced. Now, the fourth stage of the repair is under construction. Experience from earlier stages led to minor modifications of the original technology. [ABSTRACT FROM AUTHOR]

Centrifugal spinning is a technology used to generate small diameter fibers and has been extensively studied for its vast applications in biomedical engineering. Centrifugal spinning is known for its rapid production rate and has inspired the creation of other technologies which leverage the high‐speed rotation, namely Pressurized Gyration. Pressurized gyration incorporates a unique applied gas pressure which serves to provide additional control over the fiber production process. The resulting fibers are uniquely suitable for a range of healthcare‐related applications that are thoroughly discussed in this work, which involve scaffolds for tissue engineering, solid dispersions for drug delivery, antimicrobial meshes for filtration and bandage‐like fibrous coverings for wound healing. In this review, the notable recent developments in centrifugal spinning and pressurized gyration are presented and how these technologies are being used to further the range of uses of biomaterials engineering, for example the development of core‐sheath fabrication techniques for multi‐layered fibers and the combination with electrospinning to produce advanced fiber mats. The enormous potential of these technologies and their future advancements highlights how important they are in the biomedical discipline. This article is categorized under:Implantable Materials and Surgical Technologies > Nanotechnology in Tissue Repair and ReplacementNanotechnology Approaches to Biology > Nanoscale Systems in BiologyBiology‐Inspired Nanomaterials > Lipid‐Based Structures [ABSTRACT FROM AUTHOR]

Through this study, an attempt was made to produce concrete beams from self‐compacting concrete (SCC) contain expanded polystyrene (EPS) beads as coarse aggregate and waste plastic fibers (WPFs) produced from cutting disposed packing straps in site. The beams were designed according to ACI‐318‐14, where three different reinforcement ratios were chosen for the purpose of checking the conductance of thresholds made of this type of environmentally friendly concrete under bending loads. The use of EPS with WPFs had a significant positive effect in reducing the density of concrete, and the highest percentage of reduction was equal to (38.46%). Using WPFs had a positive effect in increasing the flexural toughness of concrete prisms, and the maximum increment was equal to (180%) compared with these made from the reference mix. The results proved the possibility of producing lightweight concrete from the use of EPS waste and WPFs, three of which are structurally can be classified as lightweight concrete combination of normal weight and lightweight aggregates according to specifications requirements of ASTM330/330M‐14. Reinforced lightweight SCC beams behaved under flexural loads similar to the reinforced concrete beams made from normal weight concrete counterparts under flexural loads. [ABSTRACT FROM AUTHOR]

Summary: Flexible packaging has become indispensable in the food industry due to its numerous advantages. However, it has certain drawbacks, such as limited recyclability and environmental contamination. While efforts are underway to develop more sustainable and eco‐friendly packaging options, the food industry's reliance on flexible packaging made from unsustainable petro‐based plastics is expected to continue in the foreseeable future. Therefore, more sustainable alternatives that do not sacrifice performance are required. One such option is to use nanocellulose, especially cellulose nanocrystals (CNCs), which can be reinforced into biopolymer to enhance mechanical and barrier properties. The present study aims to isolate kudzu CNCs by depolymerisation, bleaching, acid hydrolysis with 51% sulfuric acid, and mechanical dispersion. Thermogravimetric analysis (TGA) was conducted to assess the thermal stability of kudzu fibres. Further, the FTIR spectra were measured at wave number ranged 4000–500 cm−1, which showed changes in the structure after treatments and confirmed the removal of lignin and hemicellulose from the cellulose. The isolated CNCs were found to have lengths and diameters of 285.01 ± 150.33 nm and 42.78 ± 13.26 nm, respectively, with an aspect ratio of 6.43 ± 1.78. This study showed that kudzu CNCs are a suitable reinforcing material for nanocomposites. [ABSTRACT FROM AUTHOR]

Flexural design of UHPC girders with mixed reinforcement Determining the flexural strength of cross‐sections reinforced with a combination of reinforcing bars and steel fibres requires enhancing the assumptions applicable to reinforced and prestressed concrete. To account for the load‐bearing capacity of the fibres in the flexural crack, generally, a stress‐strain curve is derived from measured stress‐crack opening or load‐deflection curves. A so‐called structural characteristic length serves as reference value for conversion. Within the scope of this paper, influences from the cross‐section height and other parameters influencing crack formation are taken into account when determining the structural characteristic length. A stress block with a limit strain, which refers to reaching a "critical" crack width, is proposed as "stress‐strain curve". The "critical" crack width marks the maximum of the load‐bearing capacity of the fibres in the flexural crack in case of cross‐sections exclusively reinforced with steel fibres and the beginning of strain localisation in case of cross‐sections with mixed reinforcement. With mixed reinforced cross‐sections, strain localisation is a further possible failure mode in addition to the well‐known failure modes flexural tensile failure and flexural compression failure. The bending capacity, the moment‐curvature relationship and the failure mode of selected tests are represented very well by the proposed design approach. A parameter study shows basic relationships that could also be observed in experiments. [ABSTRACT FROM AUTHOR]

Shear bearing behaviour of UHPFRC beams with compact cross‐section The shear bearing behaviour of ultra‐high performance fibre‐reinforced concrete (UHPFRC) beams differs depending on the shape of the cross‐section. Beams with I‐shaped cross‐section typically fail in shear tension of the thin web, while beams with compact cross‐section show diagonal tension failure. Thus, design approaches, which superimpose the shear resistance of a member without shear reinforcement, the effect of prestressing as well as the bearing mechanisms of stirrups and fibres, may not be equally applicable to both types of cross‐section. The aim of the present study was to investigate the shear bearing behaviour of UHPFRC beams with compact cross‐section and, in particular, the influence of fibre volume fraction and level of prestressing on the development of the critical shear crack and the shear resistance. To this, 22 shear tests were carried out. Crack initiation and propagation were monitored using digital image correlation. A clear influence of fibre volume fraction and level of prestressing on the shear cracking load could be observed in the tests. The test specimens without prestressing mainly showed typical diagonal tension failure, while for the prestressed test specimens the concrete compression zone failed under combined bending and shearing stress. Based on the results, an additive design approach was verified. It provides a conservative estimate of the shear cracking load for all tests. [ABSTRACT FROM AUTHOR]

Summary: The current research paper presents an investigation of the piezoelectric performances of five different polyvinylidene fluoride hexafluoropropylene (PHP) systems fabricated by electrospinning. Morphological and structural analyses of neat PHP, PHP/zinc oxide 1% (PHP‐Z), PHP/mesoporous silica 1% (PHP‐M), PHP/ZnO‐mesoporous silica at 1 wt.% (PHP‐MZ1), and PHP/ZnO‐mesoporous silica at 3 wt% (PHP‐MZ3) were carried out systematically by scanning electron microscopy, transmission electron microscope, energy‐dispersive X‐ray spectroscopy (EDX), and X‐ray diffraction (XRD). The microscopic analysis results show the formation of uniform ZnO nanoflakes of approximately 5 nm in diameter, whereas mesoporous silica particles form a uniform spherical structure with a typical diameter of 5 μm. Elemental analysis by EDX spectra confirms the presence of Zn, O, and Si in the prepared nanocomposites. The crystalline β‐phase of PHP in the Fourier transformation infrared spectra rises with the addition of ZnO and mesoporous silica particles to the polymer matrix. Neat polyvinylidene fluoride has the most intense XRD peak in comparison to all other polymer nanocomposites. The fabricated flexible nanogenerator obtained from the 1% ZnO‐mesoporous silica nanocomposite shows an output voltage of 2 V, whereas the nanogenerator prepared using the neat PHP sample exhibits an output voltage of ~120 mV. All of the results indicate that the 1% ZnO‐mesoporous silica PHP nanocomposite is suitable for constructing low‐powered wearable self‐driven electrical devices. [ABSTRACT FROM AUTHOR]

This paper will focus on the use of fibre reinforced concrete on the Crossrail project in the UK. Crossrail (now named The Elizabeth Line) is a new railway running from West to East under the centre of London. This railway runs for approximately 14 km underground and five of the new stations were constructed with permanent sprayed concrete linings. Fibre reinforced concrete played a prominent role in all of the tunnelling – both for the segmental linings and the sprayed concrete tunnel (SCL) linings. Having reviewed the context of the project and the state‐of‐the‐art in tunnel design at the time of the design, this paper will describe the design approach for both the TBM and mined tunnels and their fibre reinforced linings. While the segmental lining design followed a conventional approach, the SCL tunnels adopted an innovative design with the first major application of permanent sprayed concrete in the UK and featured the first use of a spray applied waterproofing membrane (SAWM) on a major project in Europe. Performance during construction will be reviewed and conclusions will be drawn on what can be learnt from the mega project. [ABSTRACT FROM AUTHOR]

Brillouin microscopy is a new form of optical elastography and an emerging technique in mechanobiology and biomedical physics. It was applied here to map the viscoelastic properties of human hair and to determine the effect of bleaching on hair properties. For hair samples, longitudinal measurements (i.e. along the fibre axis) revealed peaks at 18.7 and 20.7 GHz at the location of the cuticle and cortex, respectively. For hair treated with a bleaching agent, the frequency shifts for the cuticle and cortex were 19.7 and 21.0 GHz, respectively, suggesting that bleaching increases the cuticle modulus and—to a minor extent—the cortex modulus. These results demonstrate the capability of Brillouin spectroscopy to address questions on micromechanical properties of hair and to validate the effect of applied treatments. [ABSTRACT FROM AUTHOR]

Poly(vinylidene fluoride) (PVDF) fibres used to develop sensors or energy harvesters have great potential in the sector of portable electronic devices and especially in the development of smart textiles. This polymorphic polymer is known for several years for its excellent piezoelectric properties related to its different crystalline phases and more particularly to the polar β‐phase is the subject of studies dedicated to the development, optimization, and characterization of β‐PVDF fibres. The presence and the evolution of the different crystalline phases are linked to different factors and can be controlled for example by changing some parameters during the process. In the case of the spinning process, the influence of the operating conditions, such as temperature and drawing on the crystalline structure is currently determined by post‐mortem analyses. Development of 'mimetic' tests to characterize in situ the evolution of the crystalline structure of a mechanically stretched polymer is a possible way. Nevertheless, this cannot totally reproduce a real process. For the first time, phase transformations and evolutions of PVDF during a melt‐spinning process were studied online thanks to in situ Raman spectroscopy measurements. Performed at different stages of the spinning line, this method allows us to follow the evolution of the crystalline phases in real time, during the key steps of the process and to conclude on the conditions for obtaining the piezoelectric phase. The successful online characterization of PVDF crystalline phases by Raman spectroscopy opens new perspectives for the optimization of these fibres by controlling the evolution of the structure when changing process parameters. [ABSTRACT FROM AUTHOR]

Water released from wood during transpiration (capacitance) can meaningfully affect daily water use and drought response. To provide context for better understanding of capacitance mechanisms, we investigated links between capacitance and wood anatomy. On twigs of 30 temperate angiosperm tree species, we measured day capacitance (between predawn and midday), water content, wood density, and anatomical traits, that is, vessel dimensions, tissue fractions, and vessel–tissue contact fractions (fraction of vessel circumference in contact with other tissues). Across all species, wood density (WD) and predawn lumen volumetric water content (VWCL‐pd) together were the strongest predictors of day capacitance (r2adj =.44). Vessel–tissue contact fractions explained an additional ~10% of the variation in day capacitance. Regression models were not improved by including tissue lumen fractions. Among diffuse‐porous species, VWCL‐pd and vessel–ray contact fraction together were the best predictors of day capacitance, whereas among semi/ring‐porous species, VWCL‐pd, WD and vessel–fibre contact fraction were the best predictors. At predawn, wood was less than fully saturated for all species (lumen relative water content = 0.52 ± 0.17). Our findings imply that day capacitance depends on the amount of stored water, tissue connectivity and the bulk wood properties arising from WD (e.g., elasticity), rather than the fraction of any particular tissue. Across 30 temperate angiosperm tree species, twig wood day capacitance was primarily driven by wood density, predawn water content and connectivity between vessels and other tissues, rather than a fraction of any particular wood tissue. [ABSTRACT FROM AUTHOR]

Synthetic vascular grafting is necessarily when the autografting is not possible in some cases. Conventional polyethylene terephthalate and expanded polytetrafluoroethylene vascular grafts are found to be effective for diameter bigger than 6 mm but not for the diameter smaller than 4 mm due to the compliance mismatch and thrombogenicity. Endothelization on the surface of the graft can reduce the risks of compliance mismatch and thrombogenicity. In order to catalyst the endothelization process, fibrous morphology similar to the extracellular matrix of our body is preferable in the vascular grafts. Apart from that, the biostability of the grafts is also an essential element to be considered as the biodegradation may reduce the efficiency of the grafts. Many polyurethanes have been recognised as biostable materials. Hence, in this study, highly aligned polyurethane fibres are fabricated using a facile dry spinning technique in the view of providing effective sites for endothelization process to occur. These fibres are immersed into the simulated body fluid for as long as 24 weeks before conducting the biostability characterisations. The biostability is assessed in three aspects, physical, mechanical and chemical properties. Results show that the fibres do not have observable or significant deteriorations in all the three aspects mentioned. [ABSTRACT FROM AUTHOR]

Summary: Soluble dietary fibres from sugarcane bagasse were extracted under alkaline conditions and characterised. Precipitated fibres were dialysed, and the fibre composition was evaluated before and after the dialysis step. Compositional analysis indicated that the fibres both before and after dialysis consisted of 39% w/w total sugars, 16% w/w protein, 10% w/w Klason lignin and 30% w/w ash. Xylose was the main neutral sugar followed by arabinose with glucose, galactose and uronic acids also present in all samples. The structural properties were also spectroscopically examined, which confirmed the presence of arabinoxylans. Macromolecular characterisation revealed that molecular weight is reduced after dialysis, indicating that a range of dietary fibres with different macromolecular characteristics may be obtained depending on the specific processing steps. The present work shows that soluble arabinoxylans may be obtained from sugarcane agricultural wastes that may be used as a source of novel dietary fibres. [ABSTRACT FROM AUTHOR]

Summary: Bird feather shafts are light, stiff and strong, but the fine details of how their structure, mechanics and function relate to one another remains poorly understood. The missing piece in our understanding may be the various fibrous layers that make up the shaft's cortex. Detailed imaging techniques are needed to enable us to capture, analyse and quantify these layers before we can begin to unravel the relationship between their structure, mechanics and function. We show that Serial‐Block‐Face scanning electron microscopy, scanning confocal polarised microscopy and synchrotron‐based computed tomography are three suitable techniques to investigate layer thickness and fibre orientation in the feather cortex. These techniques and other are discussed in terms of their ability to resolve the fibrous laminar structure of the feather cortex, on sample preparation, and on throughput. Annotated images are presented for each and less suitable techniques are presented in the Supplementary Material. Lay Description: Bird feathers have a light, stiff and strong central shaft. However, the fine details of how their structure, mechanics and function relate to one another remains poorly understood. The missing piece in our understanding may have to do with how fibrous layers within the shaft vary in thickness and alignment. Detailed imaging techniques are needed so that we can quantify some of this variation before we can revisit some long‐unanswered questions about the feather shaft's structure, mechanics and function. We investigate a number of microscopy techniques and show that three techniques are suitable for the sort of investigation that is required. These techniques and others are discussed in terms of their ability to resolve the layers' thickness and alignment, on sample preparation, and on the sample sizes they are able to process. Annotated images are presented and discussed for each of the three techniques and unsuitable techniques receive the same examination in the Supplementary Material. [ABSTRACT FROM AUTHOR]

The ferrierite crystal structure has often been subject to discussion because of the possible lowering of symmetry from the space group Immm. It mainly occurs in nature with a fibrous crystal habit, and because of the existence of line/planar defects in the framework, texture and preferred orientation effects it has been difficult to obtain an exact crystallographic model based only on the results from powder diffraction data. Therefore, nano‐single‐crystal diffraction and tomography data have been combined in order to improve the refinement with a meaningful model. High‐quality single‐crystal data, providing reliable structural information, and tomography images have been used as input for a Rietveld refinement which took into account a phenomenological description of stacking disorder and the analytical description of the preferred orientation, by means of spherical harmonics for strong texture effects. This is one of the first examples of application of synchrotron nano‐diffraction for the structure solution of fibrous minerals of micrometre to nanometre size. The high quality of the crystals allowed collection of single‐crystal X‐ray diffraction data of up to 0.6 Å resolution, leading to an unambiguous solution and precise anisotropic refinement. Nano‐single‐crystal diffraction and phase contrast tomography data were collected at ID11 and the high‐resolution powder diffraction patterns at ID22 of the European Synchrotron Radiation Facility. This detailed crystallographic characterization provides a basis for understanding the potential of ferrierite for toxicity and carcinogenicity. [ABSTRACT FROM AUTHOR]

Advanced methods, allowing the controllable synthesis of ordered structural nanomaterials with favourable charges transfer and storage, are highly important to achieve ideal supercapacitors with high energy density. Herein, we report a microliter droplet‐based method to synthesize hierarchical‐structured metal–organic framework/graphene/carbon nanotubes hybrids. The confined ultra‐small‐volume reaction, give well‐defined hybrids with a large specific‐surface‐area (1206 m2 g−1), abundant ionic‐channels (narrow pore of 0.86 nm), and nitrogen active‐sites (10.63 %), resulting in high pore‐size utilization (97.9 %) and redox‐activity (32.3 %). We also propose a scalable microfluidic‐blow‐spinning method to consecutively generate nanofibre‐based flexible supercapacitor electrodes with striking flexibility and mechanical strength. The supercapacitors display large volumetric energy density (147.5 mWh cm−3), high specific capacitance (472 F cm−3) and stably deformable energy‐supply. [ABSTRACT FROM AUTHOR]

Summary: Living cells embedded in a complex extra‐cellular matrix migrate in a sophisticated way thanks to adhesions to matrix fibres and contractility. It is important to know what kind of forces are exerted by the cells. Here, we use reflectance confocal microscopy to locate fibres accurately and determine displacement fields. Correlation techniques are used to this aim, coupled with proper digital image processing. Benchmark tests validate the method in the case of shear and stretching motions. Finally, the method is tested successfully for studying cancer cells migrating in collagen gels of different concentration. [ABSTRACT FROM AUTHOR]

Summary: Fibrous nanomaterials such as electrospun materials have many uses ranging from tissue engineering to biosensors. High‐resolution imaging is an important component in the characterization of these materials. Important parameters required to predict and study the properties of fibre rich materials include diameter and orientation distribution as well as fibre spacing. The orientations and the relative dimensions of the fibres can be measured via specially designed imaging software. Difficulties in this measurement process can arise if fibres are distributed in close proximity to each other in relation to the resolution of the imaging modality. For example, if some automation is required in the measurement process and, particularly, if the automated processes are not designed for situations where the fibres are in close proximity to each other. This work is therefore concerned with the development of automated measurement techniques to provide estimates of the diameters of fibres and also the orientation distribution. The software automatically detects special points in the fibrous materials where fibres can be considered to have some delineation from surrounding fibres. These sparse points are considered to be points at which estimates of the fibres' properties can be quantified. Aligned and randomly distributed electrospun poly(caprolactone) nanofibres were prepared. Imaging of these materials was performed with an X‐ray Computer Tomography system with an image voxel size of 0.15 × 0.15 × 0.15 μm3. Scanning Electron Microscopy images were also obtained. Fibre diameters estimated using images from both modalities using the developed techniques were found to be in agreement. Orientation distribution was summarized with multiscale entropy and found to be consistent with visual observation across different scales. Lay Description: Fibres are present in many types of materials which can include, for some materials, very small fibres e.g. a few nanometres in diameter. Very small fibres are present in collagen and elastin which are common tissues of many organs in many types of living things. The sizes of these very small fibres and how they are arranged are important information that can help in the understanding of the overall properties of these materials. Materials with very small fibres can also be synthesized using specialised techniques. The properties of these synthesized fibrous materials are also important to help in understanding how the materials will perform in various different applications. Applications are many and can range from tissue engineering to drug delivery. Some properties of these materials can be shown, visually, with the aid of 3D imaging techniques such as X‐ray Computer Tomography (XCT) or in 2D, with Scanning Electron Microscopy (SEM) but at a higher magnification. The work described here is centred around the development of computer algorithms to automatically determine material properties from 3D XCT images. Tests are performed with material samples, where the fibres are aligned (in semi‐parallel fashion) and another where the fibres are randomly oriented (criss‐crossing). The tests show that the developed algorithms are able to successfully and relatively accurately determine the diameters of the fibres. The tests also show that it is possible to quantify the relative randomness of the orientations of the fibres. [ABSTRACT FROM AUTHOR]

The potential of using rice straw (RS) in combination with wood fibre in the production of medium density fibreboard was investigated. Nano‐wollastonite (NW) was added to some of the panels to determine if it would enhance the physical and mechanical properties. It was found that satisfactory composite boards could be made with the addition of 10% RS to the wood fibre. Furthermore, the mechanical and physical properties of the composite were enhanced when NW was added. [ABSTRACT FROM AUTHOR]

ABSTRACT: Green electrospinning technique was employed to prepare chloroacetated natural rubber (CNR)/poly(vinyl alcohol) (PVA) nanofiber films by varying the addition of PVA in the range 2.5–55 wt % followed by encapsulation of 2.5 wt % fumed silica (FS). In this study, the risk of using organic solvents was eliminated using CNR in latex. The encapsulated electrospun fiber mats showed a fairly homogenous composition with enhanced water absorption ability of 703.54% ± 33.95%. The FS improved the interfacial adhesion and contributed to enhancing the intermolecular interaction between the two polymers. The mean diameter of the nanofibers decreased from 64.0 ± 19.0 to 41.0 ± 13.0 nm and significant improvement in the hydrolytic and enzymatic degradation rate was observed implying that FS can facilitate the degradation rate. Furthermore, loading of PVA and encapsulation of FS resulted in an improved stiffness of CNR at room temperature and storage modulus increased to 2.48 and 2.12 MPa, respectively. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46432. [ABSTRACT FROM AUTHOR]

Abstract: Fe3N and Fe3C nanocomposites have a wide range of applications thanks to their ceramic nature, magnetic properties, conductivity and catalytic activity, just to cite some. In many fields optimal performances are ensured by crystallinity, homogeneity and hierarchical organization. In the present paper, crystalline, magnetic and well‐defined nanofibres of iron nitride and iron carbide/carbon nanocomposite with tunable composition and size were prepared via electrospinning. The starting polymeric material was directly electrospun into fibres and then calcined, leading to a highly homogeneous final product of nanoparticles along the fibres (both outside and inside). A mechanistic study was undertaken and here discussed. The magnetic properties of the as‐prepared nanofibres were also studied. The as‐prepared final fibre mat composite material can serve as active catalyst, for example, in oxygen reduction reaction (where nanofibres outperformed mere nanoparticles), it can serve as functional support for classical catalytic processes or, thanks to its magnetic properties, can be applied in magnetic‐field assisted separation or as magneto‐active membranes. [ABSTRACT FROM AUTHOR]

Cotton fibres coated with biogenically fabricated silver nanoparticles (SNPs) are most sought material because of their enhanced activity and biocompatibility. After successful synthesis of SNPs on cotton fibres using leaf extract of Vitex negundo Linn, the fibres were studied using diffuse reflectance spectroscopy, scanning electron microscopy, nanoparticle tracking analysis, energy dispersive X‐ray, and inductively coupled plasma atomic emission spectrometry. The characterisation revealed uniformly distributed spherical agglomerates of SNPs having individual particle size around 50 nm with the deposition load of 423 μg of silver per gram of cotton. Antimicrobial assay of cotton–SNPs fibres showed effective performance against pathogenic bacteria and fungi. The method is biogenic, environmentally benign, rapid, and cost‐effective, producing highly biocompatible antimicrobial coating required for the healthcare industry. [ABSTRACT FROM AUTHOR]

The aim of this work was to investigate the effect of almond gum as dietary fibre source in enhancing the wheat bread quality. Different amounts of almond gum (2%, 5% and 10% (w/w)) were used in bread formulation. The volume, texture, crust and crumb colour, as well as the sensorial properties, were evaluated and compared to control (without almond gum). The obtained results showed that almond gum addition enhanced significantly the volume of bread. The highest volume was obtained using 2% almond gum concentration with 23.6% increase, compared to control. Using almond gum in bread formulation improved considerably its texture with a notable decrease in hardness by 61.7% and 42.5% when using 2% and 5% almond gum, respectively. The sensory analysis scores showed that the better overall acceptability was found for breads supplemented with 2% almond gum, as compared to control and breads supplemented with 5% or 10% almond gum. [ABSTRACT FROM AUTHOR]

ABSTRACT The effect of electrospinning process parameters (solution flow rate, applied voltage, spinning distance) on the size and surface morphology of porous electrospun poly(ε-caprolactone) was investigated in this study. Response surface methodology was implemented for the design and conduction of electrospinning experiments. The feed solution was a 12.5% w/v poly(ε-caprolactone) (PCL) solution in a binary solvent mixture of 90%v/v chloroform/dimethyl sulfoxide. Spinning distance of 10-25 cm, applied voltage of 10-25 kV and feed flow rate of 0.5-5 mL/h were the range of limiting values of the independent variables used for the development of a central composite design. Second-order polynomial equations, correlating electrospinning process parameters to relative pore coverage, and fiber average diameter were developed and validated. An increase in any of the investigated parameters (solution flow rate, applied voltage, spinning distance) resulted in the increase of both, pore formation on electrospun fibers, and produced fiber average diameter. Under the experimental conditions investigated, the relative pore surface coverage was 15.8-31.9% and the average fiber diameter was in the range of 1.6-3.3 μm. Applied voltage was proven to be the parameter with the strongest impact on both, fiber diameter and surface morphology. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2016, 54, 1878-1888 [ABSTRACT FROM AUTHOR]

ABSTRACT This study evaluated the releasing performance of tara tannin, a cocktail of plant polyphenols, incorporated in submicron fiber, produced by the electrospinning process. Polylactic acid was used as a polymer matrix that carried two loading levels of tara tannin, 14.3 and 22.3% dry weight in the final product. The fiber diameter of composite fibers was in the range 500-700 nm. The release of tara tannin was controlled by material attachment as there was no evidence of chemical bonding between materials. This was further confirmed by FTIR and DSC. From the five combinations of acid that were presented in tara tannin, galloylquinic acid, with the smallest molecular weight composition, was released in the largest proportion (%molar) and exhibited antioxidant activity. This was confirmed by 2,2-diphenyl-1-picrylhydrazyl assay and HPLC-MS analyses. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43646. [ABSTRACT FROM AUTHOR]

Automated handling of a natural fibrous object requires a method for acquiring the three-dimensional geometry of the object, because its dimensions cannot be known beforehand. This paper presents a method for calculating the three-dimensional reconstruction of a paper fibre on a microrobotic platform that contains two microscope cameras. The method is based on detecting curvature changes in the fibre centreline, and using them as the corresponding points between the different views of the images. We test the developed method with four fibre samples and compare the results with the references measured with an X-ray microtomography device. We rotate the samples through 16 different orientations on the platform and calculate the three-dimensional reconstruction to test the repeatability of the algorithm and its sensitivity to the orientation of the sample. We also test the noise sensitivity of the algorithm, and record the mismatch rate of the correspondences provided. We use the iterative closest point algorithm to align the measured three-dimensional reconstructions with the references. The average point-to-point distances between the reconstructed fibre centrelines and the references are 20-30 μm, and the mismatch rate is low. Given the manipulation tolerance, this shows that the method is well suited to automated fibre grasping. This has also been demonstrated with actual grasping experiments. [ABSTRACT FROM AUTHOR]

ABSTRACT Quaternary ammonium salts Quats-C8, Quats-C12, and Quats-C18 with different alkyl chain lengths have been successfully synthesized, and used for modifying silk fabrics. The optimum reaction conditions of initiator concentration, curing temperature, curing time, and monomer concentration have been studied. The modified fabrics of silk-g-C8, silk-g-C12, and silk-g-C18 were characterized by FTIR spectra. Antibacterial test showed that the modified silk fabrics possessed potent antibacterial activity against both Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli. The carbon number in the alkyl chain of monomers Quats-C8, Quats-C12, and Quats-C18 can affect the antibacterial efficacy. With longer alkyl chain, the antibacterial efficacy increased. The quaternary ammonium salts-modified silk fabrics have small change on the tensile strength and wrinkle recovery angle, and have shown potential practical application. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43450. [ABSTRACT FROM AUTHOR]

This changed with a chance discovery during SEM investigations that there are also carbon fibres with a fracture behaviour very similar to asbestos that can lead to critical fibre dust exposures.[8] In the "CarboBreak" project funded by the German Ministry of Research, we are now further investigating this fracture behavior of carbon fibres with other research institutes in order to ultimately be able to distinguish between "safe fibres" and "fibres of concern". Keywords: asbestos; fibres; material science; risk assessment; safe and sustainable by design EN asbestos fibres material science risk assessment safe and sustainable by design 1 2 2 03/31/22 20220301 NES 220301 Advanced materials (such as the TiO SB 2 sb fibers shown) are important building blocks for a post-fossil circular economy that is fostered by the Horizon Europe research framework programme from 2021 to 2026. Asbestos, fibres, material science, risk assessment, safe and sustainable by design. [Extracted from the article]

Flax (Linum usitatissimum) bast fibres are located in the stem cortex where they play an important role in mechanical support. They contain high amounts of cellulose and so are used for linen textiles and in the composite industry. In this study, we screened the annotated flax genome and identified 14 distinct cellulose synthase (CESA) genes using orthologous sequences previously identified. Transcriptomics of 'primary cell wall' and'secondary cell wall' flax CESA genes showed that some were preferentially expressed in different organs and stem tissues providing clues as to their biological role(s) in planta. The development for the first time in flax of a virus-induced gene silencing (VIGS) approach was used to functionally evaluate the biological role of different CESA genes in stem tissues. Quantification of transcript accumulation showed that in many cases, silencing not only affected targeted CESA clades, but also had an impact on other CESA genes. Whatever the targeted clade, inactivation by VIGS affected plant growth. In contrast, only clade 1- and clade 6-targeted plants showed modifications in outerstem tissue organization and secondary cell wall formation. In these plants, bast fibre number and structure were severely impacted, suggesting that the targeted genes may play an important role in the establishment of the fibre cell wall. Our results provide new fundamental information about cellulose biosynthesis in flax that should facilitate future plant improvement/engineering. [ABSTRACT FROM AUTHOR]

Polyethylene of fibrous morphology was obtained using Cp2VCl2 and VCl2( salenCl2) catalysts activated by AlEt2Cl and AlEtCl2 and heterogenized on a supported ionic liquid system prepared with SiO2 and 1-(3-triethoxysilyl)propyl-3-methylimidazolium chloroaluminate. The fibre length ranges from 15 to 60 µm, depending on the reaction conditions. The polyethylene is characterized by a high molecular weight ((1.1-2.4) × 106 g mol−1) and a narrow molecular weight distribution (1.4-2.5). It is a linear polymer, properly without branching. The DSC method reveals characteristic changes in melting temperature and crystallinity degree between the first and second scan heating cycles (141 °C and 136 °C, 71% and 46%, respectively). The wide angle X-ray spectroscopy and Fourier transform infrared spectroscopy methods give crystallinity degree values of 40% and 41%-51%. The influence of type of catalyst precursor, alkylaluminium activator, catalyst/activator molar ratio, reaction time and temperature is discussed. © 2015 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Common cereals such as wheat are widely used worldwide in extruded products. Nevertheless, other locally available grains would be beneficial for local consumers regarding taste preference, nutritional needs and sustainability. Locally available cereals, that is millet, teff, sorghum and pseudocereals, that is quinoa and amaranth flours were extruded at the same processing conditions, and the resulting properties were compared to those of extruded refined wheat flour. Amaranth flour contained the highest protein content (16%). Sorghum was the highest in calories because of its high lipid content (10%). The extrusion process greatly increased a water solubility index ( WSI) of amaranth from 11% to 61%, while the WSI level of quinoa was almost not affected ( WSI of 4%). The expansion properties varied differently among grain types. These grains had a sectional expansion index ( SEI) ranging between 11 and 13, which could not achieve the performance of the refined wheat ( SEI of 22). The lowest expansion was observed for amaranth flour which contained the lowest starch content. Sorghum extrudates, interestingly, provided comparable stress at rupture value to that of wheat. For the mechanical properties, none of these local grains could fully replace refined wheat at the employed extrusion conditions. [ABSTRACT FROM AUTHOR]

The focus of this study is contemplating the resin flow behaviour (dictating permeability) in a sisal based natural fibre mat compared to a glass fibre mat. This mainly deploys fibre reinforced plastics subjected to a vacuum infusion process. The outcome of this research emphasizes the wetting mechanism and fibre network of sisal mats, which significantly reduces the flow characteristics. In addition, it is observed that the swelling phenomenon had an insignificant or minimal influence on the permeability of the sisal fibre mat. However, employment of bio-based resin provides a considerable change in the swelling phenomenon. Hence, this factor is important to consider in permeability studies to attain higher accuracy. [ABSTRACT FROM AUTHOR]

Atmospheric carbon dioxide ( CO2), global mean temperature and interannual variability in temperature and rainfall are expected to increase significantly by the end of the 21st century. To review the effects of these factors on forage quality, we carried out a meta-analysis of climate manipulation experiments. The first notable result was a lack of effect of elevated CO2 on structural carbohydrates and digestibility. Elevated CO2 increased the total non-structural carbohydrates of forage tissues by an average of 25% and decreased forage nitrogen ( N) content by 8%. Increased legume abundance in multispecies swards can, however, maintain N concentration in the harvested biomass. There were no consistent effects of warming on contents of N, water-soluble and structural carbohydrates, or on digestibility. We highlight the continuum in the effect of water availability, from drought to irrigation, with a curvilinear increase of forage N as water availability decreased. Digestibility increased, on average, by 7% with drought, but with strong experimental variations. The review places special emphasis on discussion of the specificities of mountain and Mediterranean grasslands, the former being limited by low temperature, the latter by drought and heat. Elevated CO2 decreased forage N content in mountain areas and in temperate plains alike. It increased N content by an average of 3% in Mediterranean areas; this could be due to shifts in vegetation communities under elevated CO2 or to a greater concentration of N in plant tissues under drought conditions. Further experiments are needed to investigate the effects of combined factors, including extreme climatic events. [ABSTRACT FROM AUTHOR]

In this paper, we present a nonray-tracing technique for evaluating the three dimensional distribution of the refractive index values inside polymeric fibres. This technique, named 'single-frame computed-tomography (SFCT)', is applied to digital holography. A comparative study between the calculated optical phase values using ordinary tomography and SFCT is carried out, and a negligible deviation is detected. The proposed technique is used to determine the three-dimensional refractive index profile of isotactic Polypropylene fibres, IPP. The variation of the optical properties is measured before, during and after the formation of the necking phenomenon. In addition, SFCT technique is applied to the online determination of the change of the optical properties of IPP fibres. Holograms are given for illustration. [ABSTRACT FROM AUTHOR]

In this paper, we suggest a modification to the conventional variable wavelength interferometry. This modification allowed us to calculate the dispersion curve of each point inside polymeric fibres instead of calculating the mean dispersion of these fibres. This modified mathematical treatment was used to calculate the three-dimensional dispersion profile of isotactic polypropylene fibres suffering from necking deformation. The different steps of calculating the three-dimensional dispersion profile of the fibre were demonstrated. The application of this modified method revealed the variation of the fibre material dispersion before, inside and after the necking region. In addition, the birefringence profile of the necked isotactic polypropylene was determined using the proposed mathematical treatment. This allowed us to diagnose the interaction of the incident waves with necked polypropylene fibres, which gives extensive information on the orientation of the molecular chains during the formation of the necking phenomenon. [ABSTRACT FROM AUTHOR]

SUMMARY The shortening of the myocardial fibers is the microstructural engine that produces the contraction of the cardiac muscle. The complex interplay between fibers shortening and elastic macroscopic strain is functional to the ejection of blood into the pulmonary and arterial networks. Here, we address the contraction of the left ventricle in a finite elasticity framework, adopting the 'prolate ellipsoid' geometry and the invariants-based strain energy proposed by Holzapfel and Ogden, where the mechanical role of fibers and sheets is accounted for. We show that a microstructurally motivated mathematical model of active strain type reproduces the main indicators of normal cardiac function along the whole PV-loop without introduction of any further ad hoc law. The bare-bones mathematical model depends on one measurable parameter only, that is, the shortening ratio of the sarcomere units, which we assume to be nearly independent on the prestretch. Strict enforcement of incompressibility and novel treatment of boundary conditions are shown to be crucial to simulate the correct muscle torsion. Copyright © 2014 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Medicinal bark refers to structures outside the vascular cambium of stems, branches and roots of gymnospermous and dicotyledonous plants that are used as medicinal materials; bark is an important type of Chinese herbal medicine. However, identification of the species from which the bark comes can be very difficult, especially when the bark is dried and sliced. In our previous studies, we have found that fluorescence microscopy is a powerful tool for the identification of easily confused Chinese herbal medicines, powdered Chinese herbal medicines and decoction dregs. To establish the fluorescent characteristics by which medicinal barks can be identified, for ensuring their safe and effective use, a systematic microscopic investigation by normal light and fluorescence microscope was carried out on transverse section samples of 11 medicinal barks commonly used in China. Specifically, the fluorescent characteristics of mechanical tissues, including stone cells and fibres as well as secretory tissues, have been observed. The microscopic features of medicinal bark are here systematically and comparatively described and illustrated. Under the fluorescence microscope, various tissues emitted fluorescence of different colours, and we found that both the colours and the intensity can be used to distinguish and identify these barks. [ABSTRACT FROM AUTHOR]

In this work microgel-PVA composite fibres are prepared by means of an electrospinning process using aqueous solutions of poly(vinyl alcohol) (PVA) and poly( N-vinylcaprolactam)-based microgels. The optimal parameters are defined to fabricate homogenous composite fibres in which the microgels are embedded into a PVA matrix. It is demonstrated that the fibres can be physically and chemically crosslinked. The fibre morphology is visualised and its properties investigated by differential scanning calorimetry, DSC, thermo-gravimetric analysis, TGA, and isothermal moisture sorption analysis. The results show that the thermo-sensitive properties of the microgels are retained inside the fibres and that the degree of swelling and the moisture sorption kinetics can be tuned by changing the temperature. [ABSTRACT FROM AUTHOR]

BACKGROUND Health outcomes associated with sustained elevated blood glucose may be better managed by limiting glucose availability for uptake. Glucose release from consumed starch may be altered using various methods, but many are not suitable for high-carbohydrate foods. This study describes an approach to protect starch granules, while generally maintaining their physical characteristics, with an extract from barley using spray-drying. RESULTS The use of the extract resulted in the coating of the starch granules with a film-like material composed of β-glucans and proteins. This coincided with a reduction in starch digestion and a significant increase in the indigestible (resistant) starch component. Substitution of the starch component in a model snack bar by the coated starch was also associated with lowering starch digestion in the bar. CONCLUSION The barley extract provides a physical barrier that may limit the exposure of starch to the digestive enzymes and water, with a consequent reduction in starch digestion and the rate of glucose release. It is possible, therefore, to produce wheat starch with lower digestibility and glucose release rate that may be used as a healthier substitute in high-carbohydrate foods by coating the granules with polymers extracted from barley cereals through spray-drying. © 2013 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Juvenile gilthead sea bream ( Sparus aurata) were fed with seven experimental diets containing different proportions of protein and lipid ( P/ L): 38/29, 41/26, 44/25, 47/23, 50/22, 54/21 and 57/20 per cent of dry matter, respectively. After 12 weeks, fish fed on diet 38/29 ( P/ L) showed the lowest food efficiency and final weight. A correlation between the hepatosomatic index and fat content in the diets was observed, together with a decrease in muscle glycogen in animals fed with a 38/29 ( P/ L) diet. Whilst no statistical differences were found in flesh texture, a clear relationship was observed between elasticity and fibre density. Fillet Chroma was altered in the animals fed with the 38/29 ( P/ L) diet. The same group showed a decrease in hepatic growth factor receptor (c-met) and proliferating cell nuclear antigen ( PCNA) expression in white muscle. Protein content in the diets correlated with mammalian target of rapamycin (m TOR) phosphorylation in muscle. In conclusion, we have shown that the substitution of protein by lipid in sea bream diets can be performed up to a certain percentage without affecting fish growth, and we have demonstrated that several molecules such as Myo D, m TOR, PCNA and c-met are affected by the dietary ratio of protein to lipid and could be potential flesh quality markers. [ABSTRACT FROM AUTHOR]

This study demonstrates the first time use of electrospun nanofibrous hydrophobic membranes as gas diffusion (GD) membranes in flow injection analysis (FIA) for the determination of carbon dioxide. Different electrospun membranes are prepared from polyvinylidene fluoride (PVDF) and polystyrene (PS) polymers. To impart structural integrity for PVDF membrane, the addition of 1,4-butanediol dimethacrylate (BDDMA) is used to form an interpenetrating network, while for PS membranes are spot welded with heat-pressing at 80 °C. Heat pressed PS membranes are shown to have the best analytical sensitivity among other electrospun membranes and performed as well as the commercial PP membrane. A correlation is observed between the thickness of heat pressed PS membranes and analytical sensitivity. [ABSTRACT FROM AUTHOR]

The comparison of the low wavenumber of polarized Raman spectra (50-300 cm-1) from Bombyx mori (fresh cocoons fibres, hand-stretched ' Crins de Florence' strings from the gland content, dried gland, regenerated silk films) and Nephila madagascarensis silks reveals the high polarisation of fibre modes and the absence of polarisation for dried gland and regenerated silk films. This is consistent with X-ray diffraction measurements. The orientation of the fibroin/spidroin chains is due to the stretching during production, as for advanced synthetic fibres. The bandwidth of the 'ordered chains' signature is almost the same for the different fibres. However, the degree of polarisation seems to be higher in the case of spider fibre. The huge bandwidth of low wavenumber components of regenerated films indicates high disorder. Measurements along the fibre point out conformation changes with a periodicity (~20 mm) related to the silkworm head motion during the fabrication of the cocoon. Copyright © 2012 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

The variability in mechanical stress-strain behaviour of various silks obtained from Bombyx mori silkworm and Nephila madagascarensis spider fibres has been studied by high resolution Raman analysis using the Raman shift induced by application of a controlled strain on the νN-H mode as a probe. Silk fibres exhibiting typical 1, 2, 3 and 4 Types have been selected from their characteristic tensile stress-strain behaviour. A perfect relationship between the nanomechanic (at the scale of the chemical bond) and macroscopic (silk single fibre) behaviour is observed as in the case of other polyamide fibres (natural keratin and synthetic PA66). Copyright © 2012 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Mortars were among the first materials used for construction purposes, even from prehistoric times. Their systematic study reveals that they often contained inclusions, which were introduced with the main constituents or added as improvers of mortars' properties. The present study focuses on recording the types of inclusions found in more than 1000 mortar samples of different types (structural, renders and floor mosaic substrates), taken from various monuments of Greece. This extensive study proves that inclusions occur in all types of mortars of all periods and can be distinguished into two categories: those that are added deliberately to mortars to meet specific needs of improvement of their final properties, such as fibrous materials (wood chips, straw); and inclusions that are incorporated into the mass as impurities in the raw materials (lime and clay lumps, shells and probably charcoal particles). [ABSTRACT FROM AUTHOR]

Copyright of Canadian Journal of Chemical Engineering is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Canadian Journal of Chemical Engineering is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

1 We evaluated the efficacy and mode of action of commercially available female-equivalent dispensers of pheromone for mating disruption of codling moth Cydia pomonella (L.) (Lepidoptera Tortricidae). 2 Scentry fibres, but not Hercon flakes, were consistently as or more effective than Isomate C Plus dispensers when applied by hand at 50 dispensers per tree. 3 Individual Scentry fibres were slightly more attractive to male codling moth than Hercon flakes. 4 Efficacy of aerially applied Scentry fibres was equivalent to that of Isomate dispensers in disrupting male codling moth in 4-ha commercial apple plots. 5 Initial deposition and retention of aerially applied fibres were inefficient with approximately 44% formulation loss at application, poor rainfastness and a gradual loss of dispensers from tree canopies after application. 6 Male codling moths were captured in traps baited with lures containing 0.1 mg of pheromone and mated with tethered virgin females that were surrounded by eight fibres placed 30 cm away or 16 fibres placed 45 cm away in untreated plots and plots treated with a background of 50 Isomate dispensers per hectare. 7 A plausible explanation for mating disruption of codling moth by female-equivalent dispensers is competitive attraction without associated habituation and thus improving the effectiveness of these technologies will depend on maximizing the attractiveness of individual dispensers as well as the application density of dispensers per area of crop. [ABSTRACT FROM AUTHOR]

In many haematological conditions the only curative option is stem cell (SCT) or bone marrow (BM) transplantation. Little information exists about BM morphology following non-ablative engraftment. During the pretransplantation period and depending on the kind of pretreatment, there may be hypoplasia, residual disease and varying degrees of fibrosis. In the post-transplantation period, after 1–3 weeks of transfusion-dependent pancytopenia, the first signs of successful engraftment are indicated by the recurrence of neutrophils, monocytes and erythrocytes in the peripheral blood. In the BM there is slow regeneration of erythropoiesis, followed by the other lineages of haematopoiesis and increase in reticulin fibres or even a resolution of fibrosis. Diagnostic problems arise when neoplastic lympho- or haematopoiesis are maintained following transplantation. Moreover, there may be a significant graft versus tumour response reaction or an already relapsing disease needing aggressive treatment. On the other hand, a conspicuous dyshaematopoiesis should not be mistaken as representing a myelodysplastic syndrome. The presence of granulomas being treatment-related or a manifestation of intercurrent granulomatous disease has to be considered. More advanced knowledge of the histological features of regenerating BM will certainly aid the recognition of relapsing disease and is needed for the adequate reporting of post-transplant alterations associated with a successful or failing engraftment. [ABSTRACT FROM AUTHOR]

This paper describes methods for second-order stereology of spatial fibre systems. For stationary and isotropic fibre processes it gives practicable estimators of theK-function and the pair correlation function, which are based on planar sections. The second-order methods are applied in transmission electron microscopy analysis of blood capillaries in the rat thyroid. They lead to the result that the capillaries show an inhibitory pattern of their spatial arrangement, with a hard-core distance of about 2.6 µm. There is a close relationship to three-dimensional size characteristics estimated recently for these elliptical capillaries. [ABSTRACT FROM AUTHOR]

The term microfibril angle (MFA) in wood science refers to the angle between the direction of the helical windings of cellulose microfibrils in the secondary cell wall of fibres and tracheids and the long axis of cell. Technologically, it is usually applied to the orientation of cellulose microfibrils in the S2 layer that makes up the greatest proportion of the wall thickness, since it is this which most affects the physical properties of wood. This review describes the organisation of the cellulose component of the secondary wall of fibres and tracheids and the various methods that have been used for the measurement of MFA. It considers the variation of MFA within the tree and the biological reason for the large differences found between juvenile (or core) wood and mature (or outer) wood. The ability of the tree to vary MFA in response to environmental stress, particularly in reaction wood, is also described. Differences in MFA have a profound effect on the properties of wood, in particular its stiffness. The large MFA in juvenile wood conifers low stiffness and gives the sapling the flexibility it needs to survive high winds without breaking. It also means, however, that timber containing a high proportion of juvenile wood is unsuitable for use as high-grade structural timber. This fact has taken on increasing importance in view of the trend in forestry towards short rotation cropping of fast grown species. These trees at harvest may contain 50 % or more of timber with low stiffness and therefore, low economic value. Although they are presently grown mainly for pulp, pressure for increased timber production means that ways will be sought to improve the quality of their timber by reducing juvenile wood MFA. The mechanism by which the orientation of microfibril deposition is controlled is still a matter of debate. However, the application of molecular techniques is likely to enable modification of this process. The extent to which these techniques should be... [ABSTRACT FROM AUTHOR]