Lateral Size Research Articles

Growth mechanism and process intensification of Ni‐Al‐layered double hydroxide synthesized via coprecipitation

AbstractThis work systematically investigated the crystallization process of NiAl‐layered double hydroxide (NiAl‐LDH) with a Ni(II)/Al(III) ratio of 3 under different crystallization conditions. The results showed that the prepared NiAl‐LDH first exhibits sheet‐like morphology, which transforms into a hexagonal platelet with further growth. The lateral size and thickness of the prepared NiAl‐LDH are ~10–284 nm and ~2–31 nm, respectively. Based on the evolution of morphology, particle size and crystallinity, the growth mechanism of NiAl‐LDH was first proposed. The growth of NiAl‐LDH in the lateral dimension was governed by Ostwald ripening, while the increase in c direction was dominated by oriented particle attachment before precipitation and dissolution equilibrium. Afterward, the growth of NiAl‐LDH was dominated by the oriented particle attachment, leading to further growth of NiAl‐LDH. Moreover, a rotating packed bed (RPB) was first adopted to crystallize NiAl‐LDH. The results show that RPB can greatly enhance the growth of NiAl‐LDH.

Anti-Swelling Polyelectrolyte Hydrogel with Submillimeter Lateral Confinement for Osmotic Energy Conversion

AbstractHarvesting the immense and renewable osmotic energy with reverse electrodialysis (RED) technology shows great promise in dealing with the ever-growing energy crisis. One key challenge is to improve the output power density with improved trade-off between membrane permeability and selectivity. Herein, polyelectrolyte hydrogels (channel width, 2.2 nm) with inherent high ion conductivity have been demonstrated to enable excellent selective ion transfer when confined in cylindrical anodized aluminum pore with lateral size even up to the submillimeter scale (radius, 0.1 mm). The membrane permeability of the anti-swelling hydrogel can also be further increased with cellulose nanofibers. With real seawater and river water, the output power density of a three-chamber cell on behalf of repeat unit of RED system can reach up to 8.99 W m−2 (per unit total membrane area), much better than state-of-the-art membranes. This work provides a new strategy for the preparation of polyelectrolyte hydrogel-based ion-selective membranes, owning broad application prospects in the fields of osmotic energy collection, electrodialysis, flow battery and so on.

Lateral size dependence of photoconductivity in TMD networks

Photoconductivity is an important feature of semiconductors that finds major attention in the fields of solar cells, hydrogen and oxygen evolution reactions, and photodetectors. This feature involves a change of density of charge carriers induced by light, which is dependent on the generation of light-induced carriers and the recombination of excitons. This phenomenon has been observed in transition metal dichalcogenides (TMDs) since 2010; however, when printing such materials on flexible substrates, they form networks that would exhibit distinct transport characteristics compared to isolated TMDs crystals. In this work, TMD nanosheets are printed by vacuum filtering and their photoconductivity was measured by using a xenon lamp inside an obscure chamber. Molybdenum disulfide-based devices show higher responsivity as compared with tungsten disulfide devices, which is attributed to an increased light absorption and hydroxyl groups attached to the surface of the MoS$_2$ networks that enhance the photoconductivity by increasing the carrier lifetimes. Furthermore, the responsivity of the devices behaves similarly to the conductivity, which is modeled as networks of pairs of nanosheets and junctions through percolative paths. Finally, this is the first report that shows that the response time of the devices increases with lateral size.

Surface‐Assisted Passivation Growth of 2D Ultrathin β‐Bi2O3 Crystals for High‐Performance Polarization‐Sensitive Photodetectors

Abstract2D nonlayered materials (NLMs) have garnered considerable attention due to unique surface structure and bright application prospect. However, owing to the strong interatomic forces caused by intrinsic isotropic chemical bonds in all directions, the direct synthesis of ultrathin and large area 2D NLMs remains a tremendous challenge. Here, the surface‐assisted passivation growth strategy is designed to synthesize ultrathin and large size β‐Bi2O3 crystals with the thickness down to 0.77 nm and the lateral size up to 163 µm. These results are primarily ascribed to the bonding between Se atoms and the unsaturated Bi atoms on the surface of β‐Bi2O3, resulting in the surface passivation and promoting the obtaining of ultrathin β‐Bi2O3. Strikingly, the photodetectors based on β‐Bi2O3 flakes exhibit a high photoresponsivity of 71.91 A W−1, an excellent detectivity of 6.09 × 1013 Jones, a remarkable external quantum efficiency of 2.4 × 104%, an outstanding anisotropic photodetection and excellent UV imaging capability at 365 nm. This work sheds light on the synthesis of 2D ultrathin NLMs and promotes their applications in multifunctional optoelectronics.

The effect of lateral size of few-layer graphene oxide sheets as aqueous lubricant additives

The effect of lateral size of few-layer graphene oxide sheets as aqueous lubricant additives

Tuning the morphology and energy levels in organic solar cells with metal–organic framework nanosheets

Metal–organic framework nanosheets (MONs) have proved themselves to be useful additives for enhancing the performance of a variety of thin film solar cell devices. However, to date only isolated examples have been reported. In this work we take advantage of the modular structure of MONs in order to resolve the effect of their different structural and optoelectronic features on the performance of organic photovoltaic (OPV) devices. Three different MONs were synthesized using different combinations of two porphyrin-based ligands meso-tetracarboxyphenyl porphyrin (TCPP) or tetrapyridyl-porphyrin (TPyP) with either zinc and/or copper ions and the effect of their addition to polythiophene-fullerene (P3HT-PC71BM) OPV devices was investigated. The power conversion efficiency (PCE) of devices was found to approximately double with the addition of MONs of Zn2(ZnTCPP) -4.7% PCE, 10.45 mA/cm2 short-circuit current density (JSC), 0.69 open-circuit voltage (VOC), 64.20% fill-factor (FF), but was unchanged with the addition of Cu2(ZnTPyP) (2.6% PCE, 3.68 mA/cm2JSC, 0.59 VOC, 46.27% FF) and halved upon the addition of Cu2(CuTCPP) (1.24% PCE, 6.72 mA/cm2JSC, 0.59 VOC, 56.24% FF) compared to devices without nanosheets (2.6% PCE, 6.61 mA/cm2JSC, 0.58 VOC, 56.64% FF). Our analysis indicates that there are three different mechanisms by which MONs can influence the photoactive layer – light absorption, energy level alignment, and morphological changes. Analysis of external quantum efficiency, UV–vis and photoelectron spectroscopy data found that MONs have similar effects on light absorption and energy level alignment. However, atomic force and Raman microscopy studies revealed that the nanosheet thickness and lateral size are crucial parameters in enabling the MONs to act as beneficial additives resulting in an improvement of the OPV device performance. We anticipate this study will aid in the design of MONs and other 2D materials for future use in other light harvesting and emitting devices.

Controllable Synthesis of High-Quality Magnetic Topological Insulator MnBi2Te4 and MnBi4Te7 Multilayers by Chemical Vapor Deposition.

With a nontrivial topological band and intrinsic magnetic order, two-dimensional (2D) MnBi2Te4-family materials exhibit great promise for exploring exotic quantum phenomena and potential applications. However, the synthesis of 2D MnBi2Te4-family materials via chemical vapor deposition (CVD), which is essential for advancing device applications, still remains a significant challenge since it is difficult to control the reactions among multi-precursors and form pure phases. Here, we report a controllable synthesis of high-quality magnetic topological insulator MnBi2Te4 and MnBi4Te7 multilayers via an evaporation-rate-controlled CVD approach. The multilayers are grown on a mica substrate epitaxially, exhibiting a regular triangle shape. By controlling growth temperatures, the thickness and lateral size of the 2D MnBi2Te4 are well regulated. Furthermore, the magneto-transport measurements clearly reveal multistep spin-flop transitions for both odd- and even-number-layered MnBi2Te4 multilayers. Our study marks a significant stride toward future transformative applications in devices based on high-quality, edge- and thickness-controlled 2D magnetic topological quantum materials.

Poly(vinyl alcohol)-Assisted Exfoliation and Grafting Modification of Boron Nitride Nanosheets with a High Aspect Ratio via a Continuous Production Method for Energy Storage and Thermal Management.

Hexagonal boron nitride nanosheets (BNNS) integrating many extraordinary properties are usually combined with polymers to fabricate multifunctional dielectric materials for energy storage and thermal management. Unfortunately, the existing technologies for producing BNNS generally have the disadvantages of inefficiency and low product quality, which significantly hinder the wide application of high-value nanocomposites. Herein, a novel poly(vinyl alcohol) (PVA)-assisted pan-milling method based on the innovative solid-state shear milling (S3 M) technology is reported for the production of high-quality BNNS. The uniform three-dimensional (3D) shear force field generated by pan milling not only ensured the high aspect ratio of BNNS (the average lateral size of ∼954 nm and the average thickness of ∼3.7 nm) but also induced the mechanochemical reaction between PVA and BNNS to achieve in situ grafting modification on the BNNS surface. The simultaneous high-quality exfoliation and surface modification of BNNS positively contributed to the mechanical, dielectric, and thermal conduction properties of BNNS/PVA nanocomposites. At the BNNS content of 10 wt %, the BNNS/PVA composite film exhibited excellent robustness (Young's modulus of 5305 MPa and the tensile strength of 83 MPa), with a satisfactory breakdown strength (Eb of 134.7 MV/m) and dielectric constant (∼5 at 1000 Hz). In addition, the substantial improvement of thermal conductivity (from 0.88 to 5.59 W·m-1·K-1) guaranteed the stability of the dielectric properties of the nanocomposites at high temperatures. This pan-milling method characterized by green and efficiency is highly scalable to other two-dimensional (2D) layered materials, providing a practical strategy for the industrial fabrication of nanocomposites in elevated-temperature energy storage.

MoS2 Nanosheets at Low Doses Induced Cardiotoxicity in Developing Zebrafish via Ferroptosis: Influence of Lateral Size and Surface Modification.

The widespread applications of molybdenum disulfide (MoS2) nanosheets inevitably result in their release into aquatic environments, necessitating an exploration of their potential toxic effects on aquatic organisms. This study analyzes the cardiac responses of zebrafish larvae exposed to MoS2, with a focus on the influence of size and surface modifications. At higher concentrations (1 and 5 mg/L), MoS2 nanosheets hampered larval growth without influencing cardiomyogenesis. At lower doses (0.5-100 μg/L), small-sized MoS2 (ssMoS2, 187.2 nm) significantly impaired cardiac development, as proved by morphology abnormality, decreased heartbeat, stroke volume, and cardiac output, whereas these undesirable changes were not observed in the cysteine-modified form. Large-sized nanosheets (1.638 μm) did not localize to the heart, barely showing a cardiac disorder. Transcriptomics, biochemical analysis, and computational simulation validated that ssMoS2 aggravated Fe2+ overload through excessive ferritinophagy and ferroportin-1 inhibition, accompanied by down-regulation of glutathione peroxidase 4 and activation of PUFAs esterification, leading to ferroptosis. Significant associations between ferroptosis signals and cardiac indices, along with the ferrostatin-1 inhibition test, confirmed the ferroptosis-mediated cardiotoxicity of ssMoS2. Our study provides a key understanding of molecular events underlying MoS2-induced cardiotoxicity and highlights the importance of size and surface characteristics, which are significant for risk assessment and the safe design of nanoproducts.

Distinct nonlinear absorption behaviors in Cu1.8S nanocrystals influenced by geometry features

Spherical and lamellar [Formula: see text] nanocrystals with radial dimension of about 40[Formula: see text]nm were synthesized by the thermal injection method. Combining the crystal and morphological analysis with the photo physical property, the lamellar [Formula: see text] nanocrystals displayed the typical features of 2D metal sulfides which can be ultrasonically exfoliated into single or few layers of [Formula: see text] nanosheets due to the fact that the atomic layers were bonded by interlayer van der Waals forces. While in the spherical [Formula: see text] nanocrystals, no exfoliation or morphological change occurred after sonication. The nonlinear optical properties of spherical and lamellar [Formula: see text] nanocrystals after sonication were investigated by the [Formula: see text]-scanning technique using a 532-nm nanosecond laser pulse. The lamellar [Formula: see text] nanocrystals showed saturation absorption, reaching a normalized transmittance of 1.58 at [Formula: see text] with a [Formula: see text] value of [Formula: see text] and [Formula: see text] value of [Formula: see text]. While the spherical [Formula: see text] nanocrystals exhibited optical limiting effects, reaching the normalized transmittance of 0.38, with a [Formula: see text] value of 8[Formula: see text]cm/GW. Distinct nonlinear absorption behaviors in [Formula: see text] nanocrystals with the similar lateral size were observed in the spherical and lamellar [Formula: see text] nanocrystals, showing significant geometry feature-dependent nonlinear absorption behaviors.

Self-assembled electrically conductive biocompatible CNF wiring enables 3D-printed microfluidics applications

The emerging field of 3D-printed conductive microfluidics has a range of impactful applications, such as flexible electronics, biomedical diagnostic devices, artificial muscles, actuators, and biofuel cells. Using 3D printing for the related devices solves many problems and offers significant manufacturing advantages. At the same time it poses the unsolved problem when attempting to built electrical wiring into the print, because conductive/non-conductive hybrid 3D-printing using PolyJet technology remains outside reach. To circumvent this problem, we offer an alternative solution based on turning 3D-printed embedded microfluidic channels into electric wiring, by iteratively filling the microchannels with conductive carbon nanofibers (CNFs) suspended in organic solvent, then heating the devices to evaporate the solvent, thereby depositing the CNFs. Herein, we present the experimental procedure and the consecutive electrical measurements that establish an experimental proof-of-principle for the technique. For square microchannels of lateral size ranging from 600μm to 1080μm, the effective electrical conductivity achieved was 20.5 ±1.3Sm−1 for hard chips and 9.6 ±3.4Sm−1 for soft chips. This technique directly enables embedded wiring, a critical requirement for both electrostatic artificial muscles and benthic bacterial biofuel cells. More broadly, the technique enables 3D-printed actuators, flexible electronics, and biomedical devices requiring distributed embedded electric input and/or output. Hence, the presented development has high potential impact in multiple fields.

Electrochemical Exfoliation of Large Antioxidative MXene Flakes for Polymeric Fire Safety.

Large-size MXene flakes have drawn growing attention due to their fascinating properties, which inevitably suffer from the low yield and weak oxidation resistance. Herein, an electrochemical exfoliation approach is proposed to achieve a high recording yield of 87% for preparing large antioxidative MXene flakes with an average lateral size of 8.3µm, which combines the etching, electrolyte intercalation, interlay expansion, and short-time sonication. Moreover, the MXene flakes can keep stable for over three months in the presence of water and oxygen, and even have good stability over 500°C under an air atmosphere, ascribed to the protection of the surface electrolyte layer. Combined with bacterial cellulose, the MXene can serve as an intelligent resistance-type sensor for contact/non-contact fire alarm, and further integrate with IoT for remote fire detection and warning within 1s. In addition, the MXene significantly improves the flame-retardant properties of indoor textiles and household materials, owing to the large thermostable 2D barriers to restrain heat and mass transfer. This work establishes an innovative and efficient method to prepare the large antioxidative MXene flakes in high yield for practical usage and extends its application to polymeric fire safety.

Switchable topological polar states in epitaxial BaTiO3 nanoislands on silicon

A fascinating aspect of nanoscale ferroelectric materials is the emergence of topological polar textures, which include various complex and stable polarization configurations. The manipulation of such topological textures through external stimuli like electric fields holds promise for advanced nanoelectronics applications. There are, however, several challenges to reach potential applications, among which reliably creating and controlling these textures at the nanoscale on silicon, and with lead-free compounds. We report the realization of epitaxial BaTiO3 nanoislands on silicon, with a lateral size as small as 30-60 nm, and demonstrate stable center down-convergent polarization domains that can be reversibly switched by an electric field to center up-divergent domains. Piezoresponse force microscopy data reconstruction and phase field modeling give insight into the 3D patterns. The trapezoidal-shape nanoislands give rise to center down-convergent lateral swirling polarization component with respect to the nanoisland axis, which prevents the formation of bound charges on the side walls, therefore minimizing depolarization fields. The texture resembles a swirling vortex of liquid flowing into a narrowing funnel. Chirality emerges from the whirling polarization configurations. The ability to create and electrically manipulate chiral whirling polar textures in BaTiO3 nanostructures grown monolithically on silicon holds promise for applications in future topological nanoelectronics.

Optoacoustic lenses for lateral sub-optical resolution elasticity imaging

In this paper, we demonstrate for the first time the focusing of gigahertz coherent phonon pulses propagating in water using picosecond ultrasonics and Brillouin light scattering. We achieve this by using planar Fresnel zone plate and concave lenses with different focal lengths. Pump light illuminating the optoacoustic lens generates a focusing acoustic field, and Brillouin scattered probe light allows the acoustic field to be continuously monitored over time. Agreement of the experiment with a numerical model suggests that we can generate a focused acoustic beam down to ∼250 nm. A clear focusing effect is observed experimentally as a modulation of the envelope of the time-resolved Brillouin scattering (TRBS) signal. These findings are a crucial step toward their application in high-resolution acoustic microscopy. This work experimentally demonstrates a method to narrow the lateral size of picosecond laser-generated phonon fields in an aqueous environment, making it well-suited for 3D imaging applications in biological systems using TRBS.

Polymer‐Assisted Nucleation for Stable Single‐Crystal Perovskite Thin Films

AbstractOrganic‐inorganic hybrid perovskite single crystals have emerged as a strong candidate in photovoltaic and general optoelectronic applications. However, the high supersaturation of the precursor solution leads to the rapid formation of a significant number of nuclei and a diminished concentration of perovskite solute. Consequently, the inadequate availability of precursors poses challenges in sustaining the subsequent crystal growth phase, culminating in the development of small‐sized single crystals. In this work, we report a controlled nucleation process to foster the growth of large‐size single crystals. This method through the coordination interaction between polyacrylic acid and Pb2+ ions, and substitution of the coordination with I− ions. This reduces the formation of the Pb‐I6 complex, which promptly emerges in a state of supersaturation and acts as a nucleus, thereby effectively reducing the number of nuclei formed. The single crystals produced using this method exhibit a lateral size exceeding 5 mm, an extended absorption range, a longer carrier lifetime of 10.93 ns, and enhanced stability. These crystals demonstrate the ability to remain stable even after storage in an ambient environment (T=20±5 °C, RH=60±5 %) for a period of 20 days.

Zn-Mn composite coating codeposited with two-dimensional carbon nanoplatelets for improving corrosion resistance

Zn coating is a typical anti-corrosion coating for carbon steel. Considering the sacrificial nature of Zn coating, it is essential to enhance the corrosion resistance for the long-term performance in the practical application. In this work, two-dimensional carbon nanoplatelets (2D-CNs) with nanometer thickness (∼100 nm) and ultra-large lateral size (10–40 μm) and Mn element have been successfully co-deposited with Zn onto low carbon steel by a simple electrodeposition method. Results show that the Zn-Mn/2D-CNs composite coating is composed of Zn phase, ZnMn3 phase and a small number of 2D-CNs. The Zn-Mn/2D-CNs composite coating exhibits a modified surface quality with ultrafine grains and smaller roughness (Ra = 176 nm, Rq = 131 nm) when compared with that of Zn coatings (Ra = 798 nm, Rq = 684 nm). Besides, the inert 2D-CNs within the composite coating can act as the corrosion barriers. Therefore, the Zn-Mn/2D-CNs composite coating has excellent anti-corrosion performance, owning the lowest corrosion current densities icorr (9.2 μA cm−2) and maximum coating resistance Rcoat (1.2 kΩ·cm−2) and charge transfer resistance Rct (3.5 kΩ·cm−2), associated with its modified microstructure, Mn element with passivation property, and 2D-CNs barriers. These results demonstrate the desirable potentiality of inert 2D carbon materials in the electrodeposition of Zn-based coating for improving the corrosion resistance.

Al Islands on Si(111): Growth Temperature, Morphology and Strain

The comprehensive structural studies of thin island Al films with a thickness of 20–50 nm deposited by magnetron sputtering on Si(111) substrates in an argon plasma at a pressure of 6*10–3 mbar and a temperature from 20 to 500°C are presented. Studies of the morphology and microstructure of the films were carried out using XRD, SEM, EDS and TEM methods. It has been found that most of the islands are Al {001} and Al {111} crystallites with lateral sizes of 10–100 nm, differently conjugated with Si(111) substrate. At room temperature of the substrate, only Al {001} crystallites are epitaxially formed on it. The Al {111} crystallites epitaxially grown on the substrate dominate as the substrate temperature increases about 400°C. The influence of the temperature of the Si(111) substrate on the process of epitaxial growth of crystallites, the dynamics of their shape and structural perfection is shown. It has been found that crystallites epitaxially connected to the substrate experience deformation ε = 7 × 10–3 and ε = –2 × 10–3 for Al {001} and Al {111}, respectively. It has been shown that for thin island Al films on Si(111), the dependence of the number of crystallization centers and the particle growth rate on the supercooling temperature is consistent with the band model of crystallization. At the same time, a shift in the characteristic temperatures for the zone boundaries is observed due to the properties of the substrate. This must be taken into account when engineering the surface morphology and structural perfection of crystallites in Al island magnetron films.

Tailored graphene nanoparticles for biomedical application: preliminary in vitro characterization of the functionality in model cell lines

Thanks to an environmentally friendly physical treatment of high purity graphite, a good control of the structure of graphene nanoparticles (GNPs) has been obtained with the production of stable and reproducible GNPs water dispersions. The preparation protocol entailed ball-milling of synthetic graphite followed by sonication in water and centrifugation/separation procedures. This way, two different GNPs samples with slightly different structural characteristics were harvested: TOP60, showing an average lateral size of the graphene layers <L> = 70 nm and average number of stacked layers <N> = 4, and BOTTOM60, with <L> = 120 nm and <N> = 6. A detailed structural characterization of GNPs was performed as mandatory pre-requisite to build reliable structure/properties correlations, in terms of both biomedical efficacy and toxicity, aiming at a rationale design of tailored materials for applications in biological environments.To this end, in this study GNPs were thoroughly characterized, focusing on cytotoxicity, cellular uptake, and inflammatory response, by testing their effect in different cell lines. BOTTOM60 GNPs in culture medium and in the presence of cells showed a tendency to form big aggregates, phenomenon that was probably responsible for their cytotoxicity at high concentrations. On the other hand, TOP60 GNPs showed a diverse behavior depending on the cell type under investigation. Indeed, the nanoparticles were internalized by cells specialized in endo/phagocytosis, such as astrocytoma cells, but not by carcinoma cells of epithelial origin. Moreover, TOP60 GNPs caused a reduction of proliferation only at high concentration and did not trigger an inflammatory response in THP-1-derived macrophages.The evidence here collected paves the way for further investigations towards the development of GNPs-based drug delivery systems.

Bubbling Chemical Vapors in Molten Metal toward XIV-Group Nanosheets.

Two-dimensional (2D) XIV-group nanosheets (germanene, silicene, and stannene) possess unique physical and chemical features promising in fields of electronics, energy storage, and conversions. However, preparing these nanosheets is challenging owing to their non van der Waals structure with strong chemical bonds inside. Herein, a bubbling chemical-vapor growth method is proposed to synthesize these XIV-group nanosheets by bubbling XIV-group-element chlorides in molten sodium. During the synthetic process, XIV-group materials are formed by the reaction of XIV-group element chlorides with strong reducing sodium, then nucleated, and finally isolated to 2D nanosheets in the gas-liquid interface. With the collapse of vapor bubbles and subsequent injection, 2D nanosheets are continuously produced. The nanosheets (Ge) possess a thickness of ∼3.8 nm and a lateral size of ∼2.0 μm. Combining with graphene, the hybrid and flexible films are obtained, delivering a volumetric specific capacity of 4785 mAh cm-3 and superior cycling stability (over 4000 cycles) in lithium-ion batteries.

Chronological effects of oxygen on the structural transformations of polyacrylonitrile fibers during the rapid thermal stabilization process.

This study investigates the chronological effects of oxygen on the structural transformations of PAN fibers during the rapid thermal stabilization process. In the shorter-time period, PAN fibers undergo a few thermal-driven dehydrogenation reactions alone, while the initiation of both oxidative dehydrogenation and oxygen uptake reactions requires a longer stabilization time. Interestingly, both the amorphous regions and the lateral crystallite sizes increase simultaneously during these periods, resulting in greater exothermic enthalpy. In the longer time period, cyclization reactions begin, and the chain structures gradually become ladder-like and aromatized. In contrast to PAN fibers exposed to nitrogen, another type of cyclization reaction involving the nitrile groups occurs with negligible growth in the degree of reaction. The extent of tensile property loss in PAN fibers during this process strongly depends on the type of chemically thermal stabilization reactions. A more significant decrease in tensile strength occurs later in the longer time period, suggesting that oxygen may cause greater deterioration of the tensile strength of the PAN fibers'.