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This study of an upwelling cross-shore filament in the California Current System attempts to follow a parcel of water from upwelling source to offshore in order to characterize changes in silica cycling and associated impacts on carbon cycling under the influence of iron limitation. Water column samples were collected throughout the euphotic zone in conjunction with sediment traps following the filament in Lagrangian fashion (cycles); additional samples were taken across the filament (transects). The filament progressed from iron-replete to iron-limited throughout the study, identified by low silicic acid to nitrate ratios (Si:N) and elevated nitrate to iron (N:Fe) ratios in situ. Increases in biogenic silica to POC ratios (bSi:POC) in the water column were apparent with increasing iron limitation of the diatom-dominated community. The Lagrangian nature of the study improves overall understanding of the dynamics of biogenic silica as an upwelling filament develops to iron-limited, low Si:N water conditions. This work builds upon and adds context to previous studies which have shown that iron limitation affects silicic acid to carbon (Si:C) and silicic acid to nitrate (Si:N) uptake ratios in marine diatoms. These ratios have potential implications for both carbon and silica cycling in the ocean, impacting uptake and export of these elements. The filament was shown to transport biogenic silica laterally away from the coast, and enhanced silica ballasting was shown to be associated with increased export efficiency offshore.

The atomic structure of the complete myosin tail within thick filaments isolated from Lethocerus indicus flight muscle is described and compared to crystal structures of recombinant, human cardiac myosin tail segments. Overall, the agreement is good with three exceptions: the proximal S2, in which the filament has heads attached but the crystal structure doesn’t, and skip regions 2 and 4. At the head–tail junction, the tail α-helices are asymmetrically structured encompassing well-defined unfolding of 12 residues for one myosin tail, ∼4 residues of the other, and different degrees of α-helix unwinding for both tail α-helices, thereby providing an atomic resolution description of coiled-coil “uncoiling” at the head–tail junction. Asymmetry is observed in the nonhelical C termini; one C-terminal segment is intercalated between ribbons of myosin tails, the other apparently terminating at Skip 4 of another myosin tail. Between skip residues, crystal and filament structures agree well. Skips 1 and 3 also agree well and show the expected α-helix unwinding and coiled-coil untwisting in response to skip residue insertion. Skips 2 and 4 are different. Skip 2 is accommodated in an unusual manner through an increase in α-helix radius and corresponding reduction in rise/residue. Skip 4 remains helical in one chain, with the other chain unfolded, apparently influenced by the acidic myosin C terminus. The atomic model may shed some light on thick filament mechanosensing and is a step in understanding the complex roles that thick filaments of all species undergo during muscle contraction.

Three-dimensional printers (3DP), which are often heard with additive manufacturing, are widely used in part production. Sensitive and custom-made products in different designs can be produced more easily and quickly, but waste specimen formed after the failed three-dimensional (3D) prints cause waste and environmental pollution from the expensive filament material. It is thought that such problems can be prevented by minimizing the waste when the scrap materials generated as a result of each production are recovered. This study investigated the benefits of recycling all possible waste filament specimens, including the supports removed from the part after the defective products or supported production, by granulating and reusing in the production of new parts in the next 3D production process. Mechanical differences between the 3D specimens produced with virgin filaments to be printed with recycled filaments are investigated and it has been determined that most of the countries cause environmental pollution due to the waste of materials including additive manufacturing and 3DP processes. The use of the filament material, which takes a long time to procure from abroad and is mainly procured externally, will be increased from one time to twice or thrice, thus facilitating the availability and preventing environmental pollution.

Major uncertainties in air-sea gas flux parameterizations may arise from a yet unpredictable sea surface microlayer (SML). Its influence on gas exchange is twofold as organic matter, in particular surfactants, on one side and organisms enriched in the SML on the other can alter air-sea gas fluxes. However, spatial heterogeneity of the SML and its potential consequences for gas exchange are not well understood. This study examines the SML’s surfactant pool and the dynamics of microbial enrichment across the sharp hydrological front of a newly upwelled filament off Mauritania. The front was marked by a distinct decrease in temperature and salinity compared to the stratified water column outside the filament. Distinct chemical and microbial SML properties were observed and associated with the filament. Overall, organic matter in the SML was significantly higher concentrated inside the filament and in equivalence to the underlying water. Degradation indices derived from total amino acids (TAA) composition indicated production of fresh organic matter inside and increased degradation outside the filament. Moreover, a shift in the microbial community was observed, for instance Synechococcus spp. prevailed outside the filament. Autotrophic and heterotrophic microorganisms preferably colonized the SML outside the filament. Organic matter enrichment in the SML depended largely on the chemical nature of biomolecules. Total organic carbon (TOC), total nitrogen and total combined carbohydrates were only slightly enriched while glucose, TAA and surfactants were considerably enriched in the SML. Surfactant concentration was positively correlated to TAA, in particular to arginine and glutamic acid, indicating that fresh organic matter components enhanced surface activity. Further, TOC and surfactant concentration correlated significantly (r2 = 0.47, p-value < 0.001). The lower limit of this linear correlation hits approximately the lowest TOC concentration expected within the global surface ocean. This suggests that surfactants are primarily derived from autochthonous production and most refractory components are excluded. Using a previously established relationship between surfactants and CO2 gas exchange (Pereira et al., 2018), we estimated that surfactants suppressed gas exchange by 12% inside the filament. This could be of relevance for freshly upwelled filaments, which are often supersaturated in greenhouse gases.

The bacterial flagellum is a complex and dynamic nanomachine that propels bacteria through liquids. It consists of a basal body, a hook, and a long filament. The flagellar filament is composed of thousands of copies of the protein flagellin (FliC) arranged helically and ending with a filament cap composed of an oligomer of the protein FliD. The overall structure of the filament core is preserved across bacterial species, while the outer domains exhibit high variability, and in some cases are even completely absent. Flagellar assembly is a complex and energetically costly process triggered by environmental stimuli and, accordingly, highly regulated on transcriptional, translational and post-translational levels. Apart from its role in locomotion, the filament is critically important in several other aspects of bacterial survival, reproduction and pathogenicity, such as adhesion to surfaces, secretion of virulence factors and formation of biofilms. Additionally, due to its ability to provoke potent immune responses, flagellins have a role as adjuvants in vaccine development. In this review, we summarize the latest knowledge on the structure of flagellins, capping proteins and filaments, as well as their regulation and role during the colonization and infection of the host.

The effects of selected printing parameters on the fire properties of additively produced composites from neat polylactic acid (PLA) and wood/PLA filaments were investigated. The reaction to fire of the 3D-printed specimens was tested according to the ISO 5660-1 cone calorimeter test method. The results showed that the properties of the specimens when exposed to fire were significantly affected by the incorporation of wood flour into the PLA filament. It was also interesting that PLA specimens had much better reactions to fire than the wood/PLA specimens. Time to ignition was found to be much longer in the 3D-printed PLA specimens. Although the maximal heat release rate was a little higher in the PLA than the wood/PLA specimens, the duration of HRR was longer for the wood/PLA specimens. The initial mass of the specimens was smaller in the wood/PLA composites, but during the radiant heat exposure the mass typically decreased slower than in the PLA specimens. Slovenian Research AgencySlovenian Research Agency - Slovenia [P4-0015, BI-CN/18-20-016] The authors would like to thank the Slovenian Research Agency for financial support within the scope of the program P4-0015, as well as BI-CN/18-20-016: Study on the functional properties and thermal safety performance of wood materials and adhesives for 3D printing technology.

The amount of wasted polylactic acid (PLA) is increasing because 3D printing services are an increasingly popular offering in many fields. The PLA is widely employed in the fused deposition modeling (FDM) since it is an environmentally friendly polymer. However, failed prototypes or physical models can generate substantial waste. In this study, the feasibility of recycling PLA waste plastic and re-extruded it into new PLA filaments was investigated. An automatic PLA filament extruder was first developed for fabricating new PLA filaments. This paper also discusses the process, challenges, and benefits of recycling PLA waste plastic in an effort to fabricate new PLA filaments more sustainable. It was found that&nbsp, it was possible to fabricate PLA filament using recycled PLA waste plastic. The production cost is only 60% of the commercially available PLA filament. The tensile strength of the developed PLA filament is approximately 1.1 times that of the commercially available PLA filament. The design of experiments approach was employed to investigate the optimal process parameters for fabricating PLA filaments. The most important control factor affecting the diameter of PLA filament is the barrel temperature, followed by recycled material addition ratio, extrusion speed, and cooling distance. The optimal process parameters for fabricating PLA filament with a diameter of 1.7 mm include the barrel temperature of 184 °C, extrusion speed of 490 mm/min, cooling distance of 57.5 mm, and recycled material addition ratio of 40%.

3D-printing is an excellent tool for the prototyping and fabrication of a variety of devices. The ability to rapidly create on demand structures opens the vast possibilities for the innovations in catalysis and energy conversion/storage devices. The major bottleneck is that the materials which are suitable for 3D-printing usually do not possess the required energy conversion/storage ability. Atomic layer deposition (ALD) strategically offers homogeneous and conformal deposition of functional layers without compromising the 3D topography. Here, we show that readily fabricated fused deposition modeling extruded nanocarbon/polylactic acid (PLA) electrodes can be modified by a photoelectrocatalytic material with atomic precision. We use an archetypal material, MoS2, with high electrocatalytic hydrogen evolution reaction (HER) activity, whilst possesses high photons absorption in the visible spectral region. We optimized the ALD process at low temperature to coat 3D-printed nanocarbon/PLA electrodes with different number of MoS2 ALD cycles for photoelectrocatalytic HER. We present for the first time, the feasibility of low temperature transition metal dichalcogenide coatings on 3D-printed nanocarbon surface, unequivocally elevate the benchmark of functional coatings by ALD on any 3D-printed platforms. 3D tisk je excelentní nástroj pro přípravu prototypů a výrobu různých zařízení. Schopnost tohoto tisku rychle připravit požadované struktury otevírá možnosti pro inovaci v katalýze a zařízení na přemenu a uchování energie. Hlavní nevýhodou 3D tištěných materiálů zůstává jejich nedostatečná stabilita pro tyto aplikace. Depozice atomárních vrstev je strategická v tom, že nabízí homogenní a rovnoměrnou depozici funkčních vrstev bez kompromisů s ohledem na 3D tvarovost. V této práci ukazujeme, že elektrody na bázi směsi nanouhlíku a kyseliny polymléčné (PLA) tištěné 3D technologií filamentů bez formy mohou být modifikovýny fotoelektrokatalytickým materiálem s atomární přesností. Použili jsme pro tento účel typický materiál - MoS2 - který disponuje vysokou elektrokatalytickou aktivitou pro vývoj vodíku (HER), a který zároveň vykazuje vysokou absorpci fotonů ve viditelné spektrální oblasti. Optimalizovali jsme ALD proces při nízké teplotě s cílem pokrýt elektrody na bázi nanouhlíku/PLA s různými počty ALD MoS2 cyklů pro fotokatalytickou reakci HER. V této práci poprvé představujeme možnosti pokrýtí 3D tisknutých elektrod chalkogenidy kovů, které jednoznačně posouvají měřítko funkčních ALD vrstev na jakékoliv 3D tisknuté platformě.

Frontiers in microbiology 11, 564161 (2020). doi:10.3389/fmicb.2020.564161, Flagella are bacterial organelles of locomotion. Their biogenesis is highly coordinated in time and space and relies on a specialized flagellar type III secretion system (fT3SS) required for the assembly of the extracellular hook, rod, and filament parts of this complex motor device. The fT3SS protein FlhB switches secretion substrate specificity once the growing hook reaches its determined length. Here we present the crystal structure of the cytoplasmic domain of the transmembrane protein FlhB. The structure visualizes a so-far unseen proline-rich region (PRR) at the very C-terminus of the protein. Strains lacking the PRR show a decrease in flagellation as determined by hook- and filament staining, indicating a role of the PRR during assembly of the hook and filament structures. Phylogenetic analysis shows that the PRR is a primary feature of FlhB proteins of flagellated beta- and gamma-proteobacteria. Taken together, our study adds another layer of complexity and organismic diversity to the process of flagella biogenesis., Published by Frontiers Media, Lausanne

To date, some scientific evidence (limited proteolysis, mass spectrometry analysis, electron microscopy (EM)) has accumulated, which indicates that the generally accepted model of double-stranded of filamentous actin (F-actin) organization in eukaryotic cells is not the only one. This entails an ambiguous understanding of many of the key cellular processes in which F-actin is involved. For a detailed understanding of the mechanism of F-actin assembly and actin interaction with its partners, it is necessary to take into account the polymorphism of the structural organization of F-actin at the molecular level. Using electron microscopy, limited proteolysis, mass spectrometry, X-ray diffraction, and structural modeling we demonstrated that F-actin presented in the EM images has no double-stranded organization, the regions of protease resistance are accessible for action of proteases in F-actin models. Based on all data, a new spatial model of filamentous actin is proposed, and the F-actin polymorphism is discussed.

In this study, wet-spun filaments were prepared using lignocellulose nanofibril (LCNF), with 6.0% and 13.0% of hemicellulose and lignin, respectively, holocellulose nanofibril (HCNF), with 37% hemicellulose, and nearly purified-cellulose nanofibril (NP-CNF) through wet-disk milling followed by high-pressure homogenization. The diameter was observed to increase in the order of NP-CNF &le, HCNF &lt, LCNF. The removal of lignin improved the defibrillation efficiency, thus increasing the specific surface area and filtration time. All samples showed the typical X-ray diffraction pattern of cellulose I. The orientation of CNFs in the wet-spun filaments was observed to increase at a low concentration of CNF suspensions and high spinning rate. The increase in the CNF orientation improved the tensile strength and elastic modulus of the wet-spun filaments. The tensile strength of the wet-spun filaments decreased in the order of HCNF &gt, NP-CNF &gt, LCNF.

Chronic unresolved vascular inflammation is a critical factor in the development of atherosclerosis. Cardiovascular immunotherapy has therefore become a recent focus for treatment, with the objective to develop approaches that can suppress excessive inflammatory responses by modulating specific immune cell populations. A benefit of such immunomodulatory strategies is that low dosage stimulation of key immune cell populations, like antigen presenting cells, can subsequently propagate strong proliferation and therapeutic responses from effector cells. We have previously demonstrated that intravenous injections of anti-inflammatory nanocarriers provided atheroprotection that was mediated by regulatory T cells (Tregs) upregulated in lymphoid organs and atherosclerotic lesions. Here, we demonstrate an injectable filamentous hydrogel depot (FM-depot) engineered for low dosage, sustained delivery of anti-inflammatory nanocarriers. The bioactive form of vitamin D (aVD; 1, 25-Dihydroxyvitamin D3), which inhibits pro-inflammatory transcription factor NF-κB via the intracellular nuclear hormone receptor vitamin D receptor (VDR), was stably loaded into poly(ethylene glycol)-block-poly(propylene sulfide) (PEG-b-PPS) filomicelles. These aVD-loaded filaments underwent morphological transitions to release monodisperse drug-loaded micelles upon oxidation. This cylinder-to-micelle transition was characterized in vitro by cryogenic transmission electron microscopy (CryoTEM) and small angle X-ray scattering (SAXS). Following crosslinking with multi-arm PEG for in situ gelation, aVD-loaded FM-depots maintained high levels of Foxp3+ Tregs in both lymphoid organs and atherosclerotic lesions for weeks following a single subcutaneous injection into ApoE-/- mice. FM-depots therefore present a customizable delivery platform to both develop and test nanomedicine-based approaches for anti-inflammatory cardiovascular immunotherapy.

The present work demonstrates the spinning of conductive filaments from oppositely charged nano-scale entities, i.e., cationic cellulose nanocrystals (CNC) and anionic graphene oxide (GO), via interfacial nanoparticle complexation. Especially, the role of CNC and GO concentration in filament formation was investigated. Moreover, the chemical structure, morphology and composition of formed CNC/GO composite filaments were further characterized. The positively charged CNC formed firstly a complex film with negatively charged GO flake and then the complexed structures were further assembled into macroscale hybrid filament (diameter about 20 to 50 μm). After chemical reduction of the hybrid filament, conductive filaments with an average tensile strength of 109 ± 8 MPa and electrical conductivity of 3298 ± 167 S/m were obtained. The presented approach provides a new pathway to understand the interaction of GO and nanocellulose, and to design macroscopic, assembled and functionalized architectures of GO and nanocellulose composites.

Material Extrusion (MEX) of metallic powder-based filaments has been showing great potential as an additive manufacturing technology. MEX provides an easy solution, as an alternative to direct additive manufacturing technologies (e.g. SLM, EBM, DED) for problematic metallic powder, like copper powder, due to its reflectivity and thermal conductivity. MEX, an indirect technology, consists of 5 steps – optimising metal powder, mixing (feedstock), filament production, shaping, debinding and sintering. The great challenge in MEX is, undoubtedly, filament manufacturing for optimal green density, and consequently the sintered properties. The filament, to be extrudable, must accomplish at optimal powder volume concentration (CPVC) with good rheological performance, flexibility, and stiffness. These have a main role in the quality of the 3D objects after debinding and sintering. In this study, a feedstock composition (similar binder, additives and CPVC - 61% vol.) of copper with three different particle powder characteristics was selected, in order to highlight their role. The quality of the filaments, strands and 3D objects was analyzed by micro-CT highlighting the influence of the different powder characteristics on the homogeneity and defects of the greens. Sintered filaments were also analysed, regarding hardness, microstructure and a comparison between green and sintered defects, using micro-CT. The filament based on particles powder with D50 close to 11 µm and straight distribution of particles size shows the best homogeneity and lower defects.

This paper presents an alternative for enhancing the durability of poly (L-lactide) (PLLA) by racemic nucleation following stereo-complexation with a selected poly (D-lactide) (PLDA). The compounds are obtained by melt blending of a PLLA grade, previously designed for 3D printing but with a low heat deflection temperature and impact resistance, with grades of PLDA differing in their molecular weight (Mw), D-lactide content (DS) and concentration. Our method considered how to reveal the racemic nucleation caused by stereo-complexation and its influence on functional properties. The FTIR study we performed showed that, depending on Mw, DS and concentration of the stereo-complexer (PDLA) used, bigger or smaller spectral changes can occur. The stereo-complexation was confirmed by the DSC analysis and, for the selected compound, by the POM, SEM, AFM microscopies, functional property and shapeability as 3D printing filaments. All the obtained results sustain the idea that, if a PLLA with Mw of 4.5 × 104 g·mol−1 is modified with PDLA with a medium Mw of 11.6 × 104 g·mol−1, medium DS of 4% and 1% concentration, a racemic nucleation is possible. It produces a racemic polylactic acid (PDLLA) with improved durability and good shapeability as 3D printing filaments. These results are explicable if the dependence of the intermolecular interactions appears between the PLLA and stereo-complexer PDLA. To enlarge the durable applicability of racemic polylactic acid (PDLLA), future research should identify other parameters controling the PLA stereo-complexing as the intensifying the mobility of the macromolecules, the finding of the optimal recemic cristalization window.

The purpose of this study was to investigate the impact of the drug loading method on drug release from 3D-printed tablets. Filaments comprising a poorly water-soluble model drug, indomethacin (IND), and a polymer, polyvinyl alcohol (PVA), were prepared by hot-melt extrusion (HME) and compared with IND-loaded filaments prepared with an impregnation (IMP) process. The 3D-printed tablets were fabricated using a fused deposition modeling 3D printer. The filaments and 3D printed tablets were evaluated for their physicochemical properties, swelling and matrix erosion behaviors, drug content, and drug release. Physicochemical investigations revealed no drug–excipient interaction or degradation. IND-loaded PVA filaments produced by IMP had a low drug content and a rapid drug release. Filaments produced by HME with a lower drug content released the drug faster than those with a higher drug content. The drug content and drug release of 3D-printed tablets containing IND were similar to those of the filament results. Particularly, drug release was faster in 3D-printed tablets produced with filaments with lower drug content (both by IMP and HME). The drug release of 3D-printed tablets produced from HME filaments with higher drug content was extended to 24 h due to a swelling-erosion process. This study confirmed that the drug loading method has a substantial influence on drug content, which in turn has a significant effect on drug release. The results suggest that increasing the drug content in filaments might delay drug release from 3D-printed tablets, which may be used for developing dosage forms suited for personalized medicine.

Jasmonic acid deficiency in the lodicule leads to scattered floret opening time in cytoplasmic male sterile rice by retarding lodicule expansion through reduced accumulation of osmotic regulation substances and water., Cytoplasmic male sterile (CMS) rice has been widely used for hybrid rice seed production in China. However, CMS rice suffers from undesirable flowering habits including scattered floret opening time (FOT), which causes different FOTs among parental rice plants and greatly reduces hybrid rice seed production. Little is known about the mechanism of scattered FOT in CMS rice. Our results demonstrate that scattered FOT in CMS rice Zhenshan 97A (ZS97A) resulted from the lack of a driving force to open florets, which was directly caused by retarded lodicule expansion. Our results indicate that retarded lodicule expansion in ZS97A was caused by reduced water accumulation due to retarded accumulation of osmotic regulation substances (ORSs). Further, the retardation in accumulation of ORSs and water were caused by jasmonic acid (JA) deficiency, resulting from down-regulation of OsAOC expression. Applying JA restored scattered FOT in ZS97A by promoting ORS and water accumulation, and inducing the expansion of the lodicules. Taken together, JA deficiency inhibited lodicule expansion by retarding the accumulation of ORSs and water, leading to scattered FOT in CMS rice ZS97A.

A great improvement in valence change memory performance has been recently achieved by adding another metallic layer to the simple metal-insulator-metal (MIM) structure. This metal layer is often referred to as oxygen exchange layer (OEL) and is introduced between one of the electrodes and the oxide. The OEL is believed to induce a distributed reservoir of defects at the metal-insulator interface thus providing an unlimited availability of building blocks for the conductive filament (CF). However, its role remains elusive and controversial owing to the difficulties to probe the interface between the OEL and the CF. Here, using Scalpel SPM we probe multiple functions of the OEL which have not yet been directly measured, for two popular VCMs material systems: Hf/HfO2 and Ta/Ta2O5. We locate and characterize in three-dimensions the volume containing the oxygen exchange layer and the CF with nanometer lateral resolution. We demonstrate that the OEL induces a thermodynamic barrier for the CF and estimate the minimum thickness of the OEL/oxide interface to guarantee the proper switching operations is ca. 3 nm. Our experimental observations are combined to first-principles thermodynamics and defect kinetics to elucidate the role of the OEL for device optimization.

Water-based spinning dopes composed of enzymatically fibrillated pulp (EFP), poly(vinyl alcohol) and glutaraldehyde crosslinker were successfully spun into monofilaments. Specimens containing EFP concentrations of 50 and 60 wt% were obtained utilising a customised spinning system based on a syringe pump. Monofilaments exhibited high stiffness, good strength and low strain; maximum tensile values were obtained at a cellulose concentration of 60 wt%. Reduced graphene oxide was incorporated into the monofilaments as a lubricant, enhancing elongation while also providing a slight reinforcing effect. Mechanical behaviour was dictated by a synergy of competing interaction-types and mechanisms. Selected monofilaments were coated with cellulose acetate propionate, resulting in enhanced water strength and stability. The stability of the monofilaments was demonstrated in their ability to be tied into a knot, and to be used to prepare two- and three-dimensional structures.

Fused Filament Fabrication (FFF) is a popular additive manufacturing technique where molten polymer filament is applied in a raster pattern, layer by layer, to obtain the work piece. A necessary consequence of this method is a pronounced mechanical anisotropy of the product; the interface between the filaments is weaker compared to the filament itself. The strength of this interface is governed by the reptation theory which postulates a more efficient interpenetration of polymeric surfaces with decreasing polymer viscosity. This relationship was utilized in this work to modify a polycarbonate-acrylonitrile butadiene styrene polymer blend to produce FFF work pieces with less mechanical anisotropy, independent of printer settings. The tensile strength ratio of the printed interface to bulk tensile strength could be increased from 41% to 95%. Though the absolute bulk tensile strength decreases slightly, this method presents an easy and effective way to address the mechanical problems inherent in the FFF-method.

Non-segmented negative-strand RNA viruses, such as measles, ebola and Newcastle disease viruses (NDV), encapsidate viral genomic RNAs into helical nucleocapsids, which serve as the template for viral replication and transcription. Here, the clam-shaped nucleocapsid structure, where the NDV viral genome is sequestered, was determined at 4.8 Å resolution by cryo-electron microscopy. The clam-shaped structure is composed of two single-turn spirals packed in a back-to-back mode. This tightly packed structure functions as a seed for the assembly of a nucleocapsid from both directions, facilitating the growth of double-headed filaments with two separate RNA strings inside. Disruption of this structure by mutations in its loop interface yielded a single-headed unfunctional filament.

The influence of the physical and colloidal properties of W-stone ground lignocellulose native fines (LF) on the properties of lignocellulosic composite filaments was investigated. W-stone ground LF is a low-cost material exhibiting a microfibrillar structure with the chemical structure of native wood. The physical properties of manufactured LFs were investigated by utilising SEM imaging, turbidity measurements and image-based particle analysis using a Kajaani fibre analyser. The properties of LFs were varied by adjusting the process energy input that altered the produced material’s particle size and shape and subsequent fractionation with a wire. The reduction in particle size was observed to increase the colloidal stability of produced LFs, but no significant changes in the chemical profile of the LFs were observed. The effect of the properties of LF on the manufacture of composite filaments with carboxymethyl cellulose (CMC) was studied by using a dry-jet wet spinning approach. The smaller particle size had a positive effect on the mechanical properties of composite filaments (tenacity increased from 5.5 to up to 7.6 cN/tex). The compatibility of different plasticisers with LF–CMC composite filaments was also studied. It was observed that the number of free hydroxyls per a monomer unit of the plasticiser had a positive correlation with the plasticisation effect in the LF–CMC composite filaments. Regenerated cellulose filaments are often rather expensive to be used in many applications such as composites. The investigated filaments could thus be used in low-cost applications requiring a fully biodegradable material profile. Here, the presence of lignin may increase the structural compatibility of the produced matrix. Graphical abstract: [Figure not available: see fulltext.].

The construction of the bacterial cell envelope is a fundamental topic, as it confers its integrity to bacteria and is consequently the target of numerous antibiotics. MreB is an essential protein suspected to regulate the cell wall synthetic machineries. Despite two decades of study, its localization remains the subject of controversies, its description ranging from helical filaments spanning the entire cell to small discrete entities. The true structure of these filaments is important because it impacts the model describing how the machineries building the cell wall are associated, how they are coordinated at the scale of the entire cell, and how MreB mediates this regulation. Our results shed light on this debate, revealing the size of native filaments in B. subtilis during growth. They argue against models where MreB filament size directly affects the speed of synthesis of the cell wall and where MreB would coordinate distant machineries along the side wall., The actin-like MreB protein is a key player of the machinery controlling the elongation and maintenance of the cell shape of most rod-shaped bacteria. This protein is known to be highly dynamic, moving along the short axis of cells, presumably reflecting the movement of cell wall synthetic machineries during the enzymatic assembly of the peptidoglycan mesh. The ability of MreB proteins to form polymers is not debated, but their structure, length, and conditions of establishment have remained unclear and the subject of conflicting reports. Here we analyze various strains of Bacillus subtilis, the model for Gram-positive bacteria, and we show that MreB forms subdiffraction-limited, less than 200 nm-long nanofilaments on average during active growth, while micron-long filaments are a consequence of artificial overaccumulation of the protein. Our results also show the absence of impact of the size of the filaments on their speed, orientation, and other dynamic properties conferring a large tolerance to B. subtilis toward the levels and consequently the lengths of MreB polymers. Our data indicate that the density of mobile filaments remains constant in various strains regardless of their MreB levels, suggesting that another factor determines this constant.

The filament is the most widespread feedstock material form used for fused deposition modeling printers. Filaments must be manufactured with tight dimensional tolerances, both to be processable in the hot-end and to obtain printed objects of high quality. The ability to successfully feed the filament into the printer is also related to the mechanical properties of the filament, which are often insufficient for pharmaceutically relevant excipients. In the scope of this work, an 8 mm single screw hot-end was designed and characterized, which allows direct printing of materials from their powder form and does not require an intermediate filament. The capability of the hot-end to increase the range of applicable excipients to fused deposition modeling was demonstrated by processing and printing several excipients that are not suitable for fused deposition modeling in their filament forms, such as ethylene vinyl acetate and poly(1-vinylpyrrolidone-co-vinyl acetate). The conveying characteristic of the screw was investigated experimentally with all materials and was in agreement with an established model from literature. The complete design information, such as the screw geometry and the hot-end dimensions, is provided in this work.

High-resistance state (HRS) current has significant effect on the reliability and power consumption of resistive switching memories. Low HRS current is helpful for obtaining ultra-low power and for high ON/OFF ratio nonvolatile memory application. The reduced HRS current of a sol-gel magnesium titanate nickelate-based resistive random access memory by using nickel (II) acetylacetone as substitute for acetylacetone in magnesium titanate (MTO) was presented. Forming-free, high ON/OFF ratio of over 106, excellent current distribution and good retention at 85 °C were achieved. Moreover, the effect of nickel (Ni) on the surface roughness, operation voltage, switching cycles, HRS current, ON/OFF ratio, current distribution, and switching behavior was explored. These results indicate that the incorporation of Ni in sol-gel MTO is an effective way to achieve high-performance memory devices.

A new process for preparing thin cellulose nanofibril (CNF) filaments (thickness of 16 µm) was investigated by utilizing the dry spinning approach. In the process, CNF hydrogel was extruded through a fine nozzle onto an adhesion controlled capstan (drum) with low friction (slippery surface) at a speed of up to 11 m/s. The utilized capstan enables excellent line speed control when the slippery surface is applied, and prevents drying shrinkage of the spun filaments. The mechanical properties of prepared filaments can be optimized with the stretch ratio, the ratio of the speed of the drum surface, and the CNF jet flow. The developed method allows for manufacturing thin CNF filaments with an elevated spinning rate in a more controlled manner.

Cellulose-based filaments produced with ionic liquid-based processes have high application potential in textiles and composites to replace cotton fibres. These filaments already have unique properties that could be further improved with the addition of proteins. Keratin from poultry feathers is currently a low-value material that has potential as a renewable feedstock in material applications. In this study, cellulose filaments with chicken feather keratin were prepared by wet-spinning from an ionic liquid solution. Both keratin and cellulose were dissolved in [EMIM]AcO and spun into ethanol to regenerate cellulose and keratin and wash out the ionic liquid. The effect of keratin addition on the filament properties was investigated by microscopic, spectroscopic and strength analyses. It was observed that a small keratin addition into the cellulosic filaments improved the mechanical properties remarkably, whereas high keratin additions resulted in reduced mechanical performance. Keratin accumulation on the surface of the prepared filaments was observed. In addition, based on FTIR spectroscopy, it is likely that the morphology of cellulose changed from cellulose I to II and the β-sheets in feather keratin unfolded to unordered keratin upon dissolution and regeneration. The cellulose–protein filaments may find applications from areas where good biocompatibility and easy modifiability are required characteristics.

In this study, various nano and micro particles with different properties, including density, surface area, purity and particle morphology were used as reinforcement particles for the production of polymer composite filaments to be used for 3D printing. Acrylonitrile Butadiene Styrene (ABS) was matrix material and Multi wall carbon nanotubes (MWCNTs), SiO2, ZrB2, and, Al particles were reinforcements. Production of the composite filaments was carried out by using a twin screw extruder. Produced composite filaments were characterized via Differential Scanning Calorimeter (DSC), Scanning Electron Microscope (SEM), Energy-Dispersive X-ray Spectroscopy (EDS), tensile test and surface roughness tests. Results showed that addition of micro/nano particles into ABS matrix improved the Ultimate Tensile Strength (UTS) of the composites by around 16% compared to non-reinforced one. As a result of reinforcing with micro particles, ZrB2 and Al, the tensile strain of neat-ABS filament increased by 17.8% and 40%, respectively., Bu çalışmada, yoğunluk, yüzey alanı, saflık ve parçacık morfolojisi gibi farklı özelliklere sahip çeşitli nano ve mikro parçacıklar,3D baskıda kullanılacak polimer kompozit filamentlerin üretimi için takviye parçacıkları olarak kullanılmıştır. AkrilonitrilBütadien Stiren (ABS) matris malzemesi iken, MWCNTs, SiO2, ZrB2, Al partikülleri takviye olarak kullanılmıştır. Kompozitfilamentlerin üretimi ikiz vidalı bir ekstrüder kullanılarak gerçekleştirilmiştir. Üretilen kompozit filamentler Diferansiyel TaramalıKalorimetri (DSC), Taramalı Elektron Mikroskopu (SEM), Dispersif X-ışını Spektroskopisi (EDS), çekme testi ve yüzeypürüzlülük testleri ile karakterize edilmiştir. Sonuçlar, ABS matrise mikro/nano parçacıklarının eklenmesinin, takviyesiz ABS ilekarşılaştırıldığında kopma gerilmesini yaklaşık %16 oranında geliştirdiğini göstermiştir. ZrB2 ve Al mikro parçacıklarının takviyeedilmesi sonucunda, katkısız ABS filamentin çekme gerinimi sırasıyla %17.8 ve %40 kadar yükselmiştir.

Utilization of mechanically manufactured lignocellulosic fines (LCNFs) was investigated in making filaments and films. The LCNFs particles were prepared by using a mechanical grinding method with a w-profile grinding stone that produces mostly fines with dimensions in the micrometer scale. The chemical and elemental composition of the w-stone ground LCNFs particles was investigated. It was found that the mechanically manufactured material exhibited the chemical structure of native wood. The LCNFs particles had an anionic surface charge making them colloidally semi-stable in water. The short length of the fines particles prevents their effective mechanical entanglement, which sets some limitations on preparation of filaments and films. Filament manufacturing required the use of a composite approach with carboxymethyl cellulose (CMC) as a binder polymer. The filament was manufactured by using dry-jet wet spinning with aluminium sulfate crosslinking. The chemical composition, crosslinking mechanism, and mechanical properties of the composite filaments were investigated. The composite approach with CMC was also used to prepare composite films with good mechanical performance. The investigated LCNFs material could be utilized in all-lignocomposite applications with cellulose derivatives, where biodegradability and biobased characteristics are desired properties.

International audience; Basalt fibres are claimed to show better high temperature resistance compared to glass fibres, suggesting better prospects to survive an end-of-life composite thermal recycling process while preserving an adequate reinforcing efficiency. It is well known that sizing agents affect impregnation of fibre reinforcements during composite manufacturing, which influences the overall mechanical behaviour of the resulting composites. However, with the exception of some studies about coupling agent effects on the adhesion between basalt fibres and matrix, no information are present in literature on the wetting characteristics of basalt fibres. The main contribution of this study is the analysis of the surface properties and wetting behaviour of basalt fibres with sizing optimised for both thermoset and thermoplastic matrices. Measurements of static contact angles were performed with a tensiometric procedure designed for singles fibres, in order to determine their surface energy and its components. Modifications of surface properties due to chemical treatments and high temperature exposure were also investigated and discussed.

All tauopathies result in various forms of cognitive decline and neuronal loss. Although in some diseases, tau mutations appear to cause neurodegeneration, the toxic "form" of tau remains elusive. Tau is the major protein found within neurofibrillary tangles (NFTs) and therefore it seemed rational to assume that aggregation of tau monomers into NFTs was causal to the disease process. However, the appearance of oligomers rather than NFTs coincides much better with the voluminous neuronal loss in many of these diseases. In this study, we utilized the bigenic mouse line (rTg4510) which conditionally expresses P301L human tau. A novel tau antibody, termed Tau Oligomer Complex 1 (TOC1) was employed to probe mouse brains and assess disease progression. TOC1 selectively recognizes dimers/oligomers and appears to constitute an early stage marker of tau pathology. Its peak reactivity is coincident with other well-known early stage pathological markers such as MC1 and the early-stage phospho-marker CP13. TOC1's reactivity depends on the conformation of the tau species since it does not react with monomer under native conditions, although it does react with monomers under SDS-denaturation. This indicates a conformational change must occur within the tau aggregate to expose its epitope. Tau oligomers preferentially form under oxidizing conditions and within this mouse model, we observe tau oligomers forming at an increased rate and persisting much longer, most likely due to the aggressive P301L mutation. With the help of other novel antibodies, the use of this antibody will aid in providing a better understanding of tau toxicity within Alzheimer's disease and other tauopathies.

International audience; The filament stretching properties of various polysaccharides (including xanthan, carob, hydroxypropyl guar, hydroxypropylmethyl and hydroxyethyl celluloses) were investigated and compared to synthetic polymers generally used as texturing agents in cosmetic emulsions. The stretchability was examined by sensory evaluation as “the amount of sample that strings rather than breaks when fingers are separated”. Different behaviors were evidenced: the xanthan emulsion showed the highest stretchability, followed by the hydroxypropyl guar and hydroxyethyl cellulose emulsions while the synthetic polymers presented stretching properties to a much lesser extent. The instrumental characterization of the stretchability was conducted at a controlled speed and recorded with a camera using a texture analyzer. The maximum stretchable length at 40 mm/s was highly significantly correlated to the sensory Stringiness, thus allowing a good predictability of this attribute. Finally, this method was applied to aqueous solutions to better understand the role of the polymers in emulsion and to validate the measurement on a wider range of products.

Transition metal oxide memristors, or resistive random-access memory (RRAM) switches, are under intense development for storage-class memory because of their favorable operating power, endurance, speed, and density. Their commercial deployment critically depends on predictive compact models based on understanding nanoscale physico-chemical forces, which remains elusive and controversial owing to the difficulties in directly observing atomic motions during resistive switching, Here, using scanning transmission synchrotron x-ray spectromicroscopy to study in-situ switching of hafnium oxide memristors, we directly observed the formation of a localized oxygen-deficiency-derived conductive channel surrounded by a low-conductivity ring of excess oxygen. Subsequent thermal annealing homogenized the segregated oxygen, resetting the cells towards their as-grown resistance state. We show that the formation and dissolution of the conduction channel are successfully modeled by radial thermophoresis and Fick diffusion of oxygen atoms driven by Joule heating. This confirmation and quantification of two opposing nanoscale radial forces that affect bipolar memristor switching are important components for any future physics-based compact model for the electronic switching of these devices., Comment: 6 pages and 4 figures

"Available online 28 March 2016", Two polyhydroxy(butyrate-co-valerate) (PHBV) produced from mixed microbial cultures (MMC) fed with fermented cheese whey (CW) and recovered with different down streaming routes, were processed into filaments by plasticating extrusion. The thermorheological characteristics were improved when fermentation residues were recovered together with the MMC PHBV polymer. Thermogravimetric analysis of the extruded filaments showed that MMC PHBV with 11% residues was less degraded than pure PHBV after the thermomechanical processing. Infrared spectroscopy indicated that residues rich in OH groups were volatilized during extrusion, thereby originating filaments that were less degraded than those produced with purified MMC PHBV. Residues had no impact on the semi crystalline properties of the filaments, but were responsible for their depressed mechanical properties, significant color deterioration upon processing and narrowed the processing operating window of MMC PHBV., The authors would like to acknowledge the financial support given by the FEDER Funds through the COMPETE 2020 Programme, by the National funds from the Portuguese Foundation for Science and Technology (FCT) in the scope of Project PTDC/AGR-ALI/ 122741/2010, Project PEst-C/CTM/LA0025/2011 (Strategic ProjectdLA 25-2011-2012) and Project UID/CTM/50025/2013, and Grants SFRH/BPD/88817/2012 and SFRH/BPD/88705/2012. Additional funding by Programa Operacional Regional do Norte (ON.2) through the project “Matepro e Optimizing Materials and Processes”, with reference NORTE-07-0124-FEDER-000037 FEDER COMPETE, is also acknowledged.

Background Biological fluids often have interesting and unusual physical properties to adapt them for their specific purpose. Laboratory-based rheometers can be used to characterise the viscoelastic properties of such fluids. This, however, can be challenging as samples often do not retain their natural properties in storage while conventional rheometers are fragile and expensive devices ill-suited for field measurements. We present a portable, low-cost extensional rheometer designed specifically to enable in situ studies of biological fluids in the field. The design of the device (named Seymour) is based on a conventional capillary break-up extensional rheometer (the Cambridge Trimaster). It works by rapidly stretching a small fluid sample between two metal pistons. A battery-operated solenoid switch triggers the pistons to move apart rapidly and a compact, robust and inexpensive, USB 3 high speed camera is used to record the thinning and break-up of the fluid filament that forms between the pistons. The complete setup runs independently of mains electricity supply and weighs approximately 1 kg. Post-processing and analysis of the recorded images to extract rheological parameters is performed using open source software. Results The device was tested both in the laboratory and in the field, in Brunei Darussalam, using calibration fluids (silicone oil and carboxymethyl cellulose solutions) as well as Nepenthes pitcher plant trapping fluids as an example of a viscoelastic biological fluid. The fluid relaxation times ranged from 1 ms to over 1 s. The device gave comparable performance to the Cambridge Trimaster. Differences in fluid viscoelasticity between three species were quantified, as well as the change in viscoelasticity with storage time. This, together with marked differences between N. rafflesiana fluids taken from greenhouse and wild plants, confirms the need for a portable device. Conclusions Proof of concept of the portable rheometer was demonstrated. Quantitative measurements of pitcher plant fluid viscoelasticity were made in the natural habitat for the first time. The device opens up opportunities for studying a wide range of plant fluids and secretions, under varying experimental conditions, or with changing temperatures and weather conditions. Electronic supplementary material The online version of this article (doi:10.1186/s13007-015-0059-5) contains supplementary material, which is available to authorized users.

Precursor filaments of Dy-Ba-Cu-O super-conductor were prepared by a solution spinning method and partially melting in an atmosphere gas with various oxygen concentrations. It was found that the transport Jc value at 77 K and 0 T of the filamentary sample was strongly dependent on the partial-melting temperature and gas atmosphere. The samples partially melted under flowing 1%O/sub 2/+Ar gas exhibited Jc values larger than 10/sup 4/ A/cm/sup 2/ over a wide temperature range of 980-1040/spl deg/C and a dense microstructure. The filamentary sample with the starting composition of Dy:Ba:Cu=1.18:2.12:3.09 treated at 1020/spl deg/C under flowing 1%O/sub 2/+Ar showed a transport Jc value greater than 4.3/spl times/10/sup 4/ A/cm/sup 2/ at 77 K and 0 T, and the Jc value of 2.0/spl times/10/sup 3/ A/cm/sup 2/ was maintained up to the magnetic fields of 14 T. The samples partially melted in 20%O/sub 2/+Ar gas and 100%O/sub 2/ gas showed relatively low Jc value of 6.0/spl times/10/sup 3/ A/cm/sup 2/ and 1.2/spl times/10/sup 2/ A/cm/sup 2/ at most.

Aggregation of highly phosphorylated tau into aggregated forms such as filaments and neurofibrillary tangles is one of the defining pathological hallmarks of Alzheimer’s disease and other tauopathies. Hence therapeutic strategies have focused on inhibition of tau phosphorylation or disruption of aggregation. However, animal models imply that tau-mediated dysfunction and toxicity do not require aggregation but instead are caused by soluble hyper-phosphorylated tau. Over the years, our findings from a Drosophila model of tauopathy have reinforced this. We have shown that highly phosphorylated wild-type human tau causes behavioral deficits resulting from synaptic dysfunction, axonal transport disruption, and cytoskeletal destabilization in vivo. These deficits are evident in the absence of neuronal death or filament/tangle formation. Unsurprisingly, both pharmacological and genetic inhibition of GSK-3β rescue these tau phenotypes. However, GSK-3β inhibition also unexpectedly increases tau protein levels, and produces insoluble granular tau oligomers. As well as underlining the growing consensus that tau toxicity is mediated by a highly phosphorylated soluble tau species, our findings further show that not all insoluble tau aggregates are toxic. Some tau aggregates, in particular tau oligomers, are non-toxic, and may even be protective against tau toxicity in vivo. This has serious implications for emerging therapeutic strategies to dissolve tau aggregates, which might be ineffective or even counter-productive. In light of this, it is imperative to identify the key toxic tau species and to understand how it mediates dysfunction and degeneration so that the effective disease-modifying therapies can be developed.

We describe the purification, crystallization and structure for the GTP-binding domain of human septin 7 (SEPT7G). We show that it forms filaments within the crystal lattice which employ both the G and NC interfaces, similar to those seen in the hetero-filament of SEPT2/6/7. The NC interface is considered promiscuous as it is absent from the hetero-filament. Such promiscuity could provide the potential for permuting monomers along a filament in order to generate diversity in hetero-polymers. On the other hand, our results suggest that the G and NC interfaces may be necessary but insufficient for determining correct hetero-filament assembly. Structured summary of protein interactions SEPT7G and SEPT7G bind by X-ray crystallography ( View interaction ). SEPT7 G and SEPT7 G bind by molecular sieving ( View interaction ).

Air-jet texturing of technical polyester yarns was performed in order to improve its adhesion to rubber. The air-jet texturing parameters were selected with great care to minimize the mechanical loss. H-adhesion tests were used to characterize the adhesion of the yarns to rubber. A significant increase in the adhesion of dimensionally stable polyethylene terephthalate yarn, textured with an overfeed level of 15% (DSPET15), was recorded, while a decrease in the adhesion of high tenacity polyethylene terephthalate (HTPET) yarn was observed for all overfeed levels. The effects of air-jet texturing on the adhesion of technical polyester yarns were discussed in terms of changes in the yarn geometry and changes on the single fiber surfaces. Changes in the yarn geometry were investigated by optical microscopy studies, while changes on the fiber surface were investigated by scanning electron microscopy (SEM), atomic force microscopy (AFM) and environmental scanning electron microscopy (ESEM) studies. It was observed that air-jet texturing alters both the yarn geometry and the single fiber surfaces, leading to a change in the adhesion to rubber. (C) Koninklijke Brill NV, Leiden, 2011

High resolution visualization of plasma plume tearing-off during rapid power decrease in amplitude modulated microwave argon jet. Vizualizace odtrhávání filamentů během prudkého poklesu výkonu při amplitudově modulovaném výkonu. High resolution visualization of plasma plume tearing-off during rapid power decrease in amplitude modulated microwave argon jet.

This paper discusses the breakup of capillary jets of dilute polymer solutions and the dynamics associated with the transition from dripping to jetting. High-speed digital video imaging reveals a new scenario of transition and breakup via periodic growth and detachment of large terminal drops. The underlying mechanism is discussed and a basic theory for the mechanism of breakup is also presented. The dynamics of the terminal drop growth and trajectory prove to be governed primarily by mass and momentum balances involving capillary, gravity and inertial forces, whilst the drop detachment event is controlled by the kinetics of the thinning process in the viscoelastic ligaments that connect the drops. This thinning process of the ligaments that are subjected to a constant axial force is driven by surface tension and resisted by the viscoelasticity of the dissolved polymeric molecules. Analysis of this transition provides a new experimental method to probe the rheological properties of solutions when minute concentrations of macromolecules have been added., Schlumberger Foundation, MIT Class of 1951 Fellowship Fund

The effects of quenching air temperature, quenching air speed and winding speed in the melt spinning process of poly(ethylene terephthalate) fibres with a titre of 147 dtex and 96 filaments on dye uptake were investigated. The ranges used for quenching air temperature, quenching air speed and winding speed were 17-27 degrees C, 0.3-0.7 m/s and 2600-3800 m/min, respectively. Specimens were dyed and their colour strengths (K/S values) were measured using a spectrophotometer. The results were statistically analysed.

Human BRCA2, a breast and ovarian cancer suppressor, binds to the DNA recombinase RAD51 through eight conserved BRC repeats, motifs of approximately 30 residues, dispersed across a large region of the protein. BRCA2 is essential for homologous recombination in vivo, but isolated BRC repeat peptides can prevent the assembly of RAD51 into active nucleoprotein filaments in vitro, suggesting a model in which BRCA2 sequesters RAD51 in undamaged cells, and promotes recombinase function after DNA damage. How BRCA2 might fulfill these dual functions is unclear. We have purified a fragment of human BRCA2 (BRCA2(BRC1-8)) with 1127 residues spanning all 8 BRC repeats but excluding the C-terminal DNA-binding domain (BRCA2(CTD)). BRCA2(BRC1-8) binds RAD51 nucleoprotein filaments in a ternary complex, indicating it may organize RAD51 on DNA. Human RAD51 is relatively ineffective in vitro at strand exchange between homologous DNA molecules unless non-physiological ions like NH4+ are present. In an ionic milieu more typical of the mammalian nucleus, BRCA2(BRCI-8) stimulates RAD51-mediated strand exchange, suggesting it may be an essential co-factor in vivo. Thus, the human BRC repeats, embedded within their surronding sequences as an eight-repeat unit, mediate homologous recombination independent of the BRCA2(CTD) through a previously unrecognized role in control of RAD51 activity.

A new nanocomposite material consisting of poly(4-vinylpyridine) (PVP) and vermiculite is synthesized by the intercalative redox polymerization of VP in the gallery of copper(II) ion-exchanged vermiculite. The formation of a single filament of the polymer in the gallery is confirmed by the increase in gallery spacing of 4.7 A as indicated by X-ray diffraction (XRD) analysis. Electron spin resonance studies confirm the presence of Cu(II) upon ion exchange and its absence following redox polymerization. The amount of polymer present in the gallery is found to be ∼18–19 mass % by thermogravimetric analysis. Confining the polymer to the gallery spacing in vermiculite results in enhanced thermal stability that is evident from the increase in the initial decomposition temperature by ∼300°C. Differential scanning calorimetry of the nanocomposite indicates that the polymer is confined to a restricted geometry because of the absence of a glass-transition temperature, which confirms the XRD finding. The IR absorption peaks corresponding to PVP and the expected PVP UV π–π* transition at 275 nm, along with the XRD and thermal data confirms that the gallery expansion is due to the PVP filament. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 555–561, 2001