Web-like Structure Research Articles

Origin of the biphase nature and surface roughness of biogenic calcite secreted by the giant barnacle Austromegabalanus psittacus

The calcite grains forming the wall plates of the giant barnacle Austramegabalanus psittacus have a distinctive surface roughness made of variously sized crystalline nanoprotrusions covered by extremely thin amorphous pellicles. This biphase (crystalline-amorphous) structure also penetrates through the crystal’s interiors, forming a web-like structure. Nanoprotrusions very frequently elongate following directions related to the crystallographic structure of calcite, in particular, the <− 441> directions, which are the strongest periodic bond chains (PBCs) in calcite. We propose that the formation of elongated nanoprotrusions happens during the crystallization of calcite from a precursor amorphous calcium carbonate (ACC). This is because biomolecules integrated within the ACC are expelled from such PBCs due to the force of crystallization, with the consequent formation of uninterrupted crystalline nanorods. Expelled biomolecules accumulate in adjacent regions, thereby stabilizing small pellicle-like volumes of ACC. With growth, such pellicles become occluded within the crystal. In summary, the surface roughness of the biomineral surface reflects the complex shape of the crystallization front, and the biphase structure provides evidence for crystallization from an amorphous precursor. The surface roughness is generally explained as resulting from the attachment of ACC particles to the crystal surface, which later crystallised in concordance with the crystal lattice. If this was the case, the nanoprotrusions do not reflect the size and shape of any precursor particle. Accordingly, the particle attachment model for biomineral formation should seek new evidence.

Redispersion and structural change evaluation of dried microfibrillated cellulose

Commercializing dried microfibrillated cellulose (MFC) has always been a challenge mainly due to the tendency of MFC to aggregate. In this study MFC samples were submitted to drying/redispersion cycles at different temperatures. Morphology, crystallinity and mechanical performance of films were analyzed throughout the cycles. Microscopy images, particle size and stability in water showed that aggregation happens more severely with 5 drying/redispersion cycles and at drying temperatures of 75 and 100 °C. Particles once-dried at 20 °C formed the same size and web-like structure as the MFC-control. Crystallinity and crystallite sizes increased with drying/redispersion cycles especially when dried at 75 and 100 °C, however drying/redispersion cycles also led to a reduction in mechanical performance due to aggregation. While oven-drying is not the most suitable method, milder action at room temperature once-drying led to suspension stability in water, morphology and mechanical properties close to never-dried MFC, which makes this treatment a feasible option to maintain cellulose quality.

The name to remember: Flexibility and contextuality of preliterate folk plant categorization from the 1830s, in Pernau, Livonia, historical region on the eastern coast of the Baltic Sea

Ethnopharmacological relevanceResearch on the folk categorization of nature in preliterate societies in Europe is complicated due to the fragmentation of the information available and is rarely undertaken. Yet the data is valuable and may provide, in certain circumstances, important insights, if not into novel medicines, then into the historical logic of selection and memorisation of plants useful from a medicinal perspective. Aims of the studyWe aim to understand the ethnobotany of a preliterate society by analysing the emic (derived from people) perspective on nature-related culture of one of Europe's smaller nations, whose written language and culture was shaped in the 18th-19th centuries by other, larger nations of Europe, and thus from the etic (academic) perspective. We attempt to identify how folk categorization is reflected in the relationships between plant names and uses and to map the structure of those relationships. Data and methodsWe base our analysis on one of the oldest ethnobotanical manuscripts and herbaria of the Baltic governorates, compiled in 1831 by an amateur botanist, Baltic German Pastor Johann Heinrich Rosenplänter (1782–1846), which was derived from conversations with his parishioners from the tiny Pärnu parish. The historical dataset was critically analysed from an ethnobotanical perspective in light of recent identifications of the herbarium specimens. ResultsAlthough the Rosenplänter collection is fragmentary, the logic of plant categorization by non-literate peasants at that time is clearly seen in the data. Plants preserved in the herbarium were predominantly used for ethno-medicinal, food or ethno-veterinary purposes, such as treating chronic skin and joint diseases as well as severe acute diseases in humans and animals. Among 129 folk taxa analysed, more than one third had apparent purpose-related plant names providing clear links to their use, whereas a few multifunctional plants had several names reflecting diverse uses. For example, Hypericum spp., which was used in three different ways, had three semantically distinct names. However, among the plants that Rosenplänter collected, there were also some that were simply named and described by people but lacked any usability data (e.g., Trollius europaeus), meaning that use as such was not the primary criterion for recognising a plant. The web-like structure of preliterate thinking in plant-related knowledge reveals a deep relationship with the environment and the interpretation of new elements through familiar natural objects. ConclusionOur findings demonstrate that historical ethnobotanical data, if thoughtfully analysed, can be used not only for comparative purposes, but also for understanding the logic of preliterate thinking. We encourage future in-depth studies of historical ethnobotanical data in Europe in order to understand the relationship between nature and culture of native European populations.

Quantification of Neutrophil Extracellular Traps Isolated From Mouse Tissues.

One of the most intriguing functions of neutrophils is the production of neutrophil extracellular traps (NETs), which are formed when neutrophils decondense their internal DNA and extrude it along with cytotoxic proteins in a web-like structure. This process allows neutrophils to trap and kill pathogens, and is also associated with multiple hematological and autoimmune conditions. Due to their rapid degradation, there are many challenges in accurately and specifically detecting and quantifying NETs. Microscopy is the gold standard for NET detection, but is not optimal for large-scale screening. Furthermore, methods relying on detection of free DNA or on flow cytometry-based examination of NET-associated markers can be nonspecific, time-consuming, and expensive. Here, we describe an innovative, quick, specific, and inexpensive conventional flow cytometry method for detecting neutrophils on the verge of forming NETs. These methods utilize pulse-shaped analysis (PulSA) to distinguish resting neutrophils from those with decondensed DNA, a prerequisite for NET formation. An increase in DNA-diffuse neutrophils is found in cell populations after exposure to NET-inducing stimuli, consistent with the DNA decondensation expected during neutrophil NET formation. These populations are only observed in granulocytes, validating the specificity of this method. We describe protocols optimized for neutrophils retrieved from mouse blood, spleen, and bone marrow. The relative speed and simplicity of the method described here makes it a useful tool for detecting NET formation in large-scale experiments. © 2020 Wiley Periodicals LLC. Basic Protocol: Detection of nuclear decondensation in neutrophils from stimulated murine bone marrow Alternate Protocol 1: Detection of nuclear decondensation in neutrophils from splenocytes Alternate Protocol 2: Detection of nuclear decondensation in neutrophils from blood Support Protocol 1: Cryopreservation and defrosting of samples Support Protocol 2: Paraformaldehyde fixation of samples.

Tilted-hat mushroom billiards: Web-like hierarchical mixed phase space

Mushroom billiards are formed, generically, by a semicircular hat attached to a rectangular stem. The dynamics of mushroom billiards shows a continuous transition from integrability to chaos. However, between those limits the phase space is sharply divided in two components corresponding to regular and chaotic orbits, in contrast to most mixed phase space billiards. In this paper we show that tilting the hat of a mushroom billiard produces a highly non-trivial (i.e. non-KAM) mixed phase space. Moreover, for small tilting, this phase space shows a web-like hierarchical structure.

Oil‐Water Separation: Facile and Green Route to Fabricate Bacterial Cellulose Membrane with Superwettability for Oil–Water Separation (Adv. Sustainable Syst. 7/2020)

In article number 2000042, Huazheng Sai, Rui Fu and co-workers report an environmentally friendly fabrication process to obtain bacterial cellulose membranes with superwettability for oil-water separation. The ultrafine nanofiber web-like structure and the intrinsic hydrophilicity of bacterial cellulose endow the membrane with superwettability and high oil-water separation efficiencies for both oil-water mixtures and emulsions.

Electrospun N-doped carbon nanofibers confined Fe1-xS composite as superior anode material for sodium-ion battery

Abstract Iron sulfides show great application potential for sodium storage. However, the volume changes and dissolution of polysulfide intermediates severely restrict the lifespan of cells. In this work, N-doped carbon nanofibers encapsulated Fe1-xS nanoparticles composite (denoted as Fe1-xS/N-CNFs) was synthesized via electrospinning technique and following thermal treatment. Take advantage of the flexible web-like structure constructed by continuous fibers, the as-obtained membrane can be directly utilized as free-standing anodes for SIBs. Besides, the well confinement of CNFs can effectively buffer volume changes and prevent aggregation of active material. As a result, the as-obtained electrode achieved outstanding sodium storage performances. Specifically, a reversible discharge capacity of 549.1 mA h g−1 can be delivered at 0.1 A g−1. After 800 cycles at 1 A g−1, a specific capacity of 241.1 mA h g−1 still could be obtained, manifesting excellent cyclic stability of the composite.

Micro- and nano-celluloses derived from hemp stalks and their effect as polymer reinforcing materials

Fiber-reinforced polymers have emerged as one of the most popular methods to improve the polymers’ characteristics owing to their prominent properties. This study aimed to investigate the properties of cellulose microfibers (CMF), cellulose nanocrystals (CNC) and cellulose nanofibrils (CNF) extracted from hemp stalks, then their effect as reinforcement for the PVA-polymer. CMF have been extracted from hemp stalks with a diameter and yield of 16.96 μm and 63 %, respectively. Needle-shaped CNC were obtained from CMF using sulfuric acid hydrolysis at two hydrolysis times, while CNF exhibited a web-like structure obtained using TEMPO-oxidation followed by mechanical treatment. Cellulose derivatives were utilized to develop cellulose-based PVA composites; their transparency, chemical structure, thermal stability and mechanical properties were investigated. The incorporation of nanocellulose demonstrated a significant increase in mechanical properties compared to the neat PVA. The extracted nanocellulose could be used as nanofillers for the preparation of transparent and mechanically strong PVA-based nanocomposites.

Research progress on neutrophil extracellular traps in tumor

Neutrophil extracellular traps(NET)is neutrophil-derived extracellular fiber web-like structure, composed of DNA scaffold studded with various active proteins. In addition to its bactericidal effect, NET is closely related to various diseases including immune disease, thrombosis and tumor. Recently, lots of researches have shown that NET is highly expressed in a variety of tumors, tumor cells and microenvironment can promote NET formation, whereas NET participates in tumor progression as well, and is closely related to tumor proliferation, metastasis and thrombosis, which provides new clinical thinking in tumor diagnosis as well as treatment indeed. This review will focus on the research progress of NET and tumor, meanwhile make a prospect for its clinical application value.

Spider web-inspired ultra-stable 3D Ti3C2TX (MXene) hydrogels constructed by temporary ultrasonic alignment and permanent in-situ self-assembly fixation

The restacking tendency of 2D Ti3C2TX (MXene) sheets is the main obstacle preventing their application as functional materials in hydrogel. Herein, we fabricated novel ultra-stable 3D MXene-polyacrylamide (PAM) nanocomposite hydrogels inspired by the structure of a spider web. In particular, MXene nanosheets were uniformly located in a gel medium by precise alignment of sonication treatments, followed by the in-situ self-assembly of PAM hydrogel. In this instance, the MXene nanosheets are well-confined and trapped (via strong interactions) by the interwoven spider web-like structure of the PAM chains, which grow in-situ on the surface of the nanosheets. This approach proved effective to solve problems associated with the poor stability of MXene nanosheets in the hydrogel; more prominently, the tight cross-linked structure endows the MXene-PAM hydrogel with anti-compressive and anti-swelling capabilities; the continuous distribution of MXene nanosheets connected by the PAM network creates electron transport pathways and proton transport bridges in the hydrogel. Therefore, the hydrogel can be employed as a temperature and strain sensor or as a component of moist-electric nanogenerator.

A New Strategy to Produce Hemp Fibers through a Waterglass-Based Ecofriendly Process.

Natural fibers such as kenaf, hemp, flax, jute, and sisal have become the subject of much research as potential green or eco-friendly reinforcement composites, since they assure the reduction of weight, cost, and CO2 release with less reliance on oil sources. Herein, an inexpensive and eco-friendly waterglass treatment is proposed, allowing the production of silica-coated fibers that can be easily obtained in micro/nano fibrils through a low power mixer. The silica coating has been exploited to improve the chemical compatibility between fibers and the polymer matrix through the reaction of silanol groups with suitable coupling agents. In particular, silica-coated fibers easily functionalized with (3-Aminopropyl) triethoxysilane (APTS) were used as a filler in the manufacturing of epoxy-based composites. Morphological investigation of the composites through Scanning Electron Microscopy (SEM) demonstrated that the filler has a tendency to produce a web-like structure, formed by continuously interconnected fibrils and microfibrils, from which particularly effective mechanical properties may be obtained. Dynamic Mechanical Analysis (DMA) shows that the functionalized fibers, in a concentration of 5 wt%, strongly affect the glass transformation temperature (10 °C increase) and the storage modulus of the pristine resin. Taking into account the large number of organosilicon compounds (in particular the alkoxide ones) available on the market, the new process appears to pave the way for the cleaner and cheaper production of biocomposites with different polymeric matrices and well-tailored interfaces.

Preparation of nanocellulose from steam exploded poplar wood by enzymolysis assisted sonication

By exploiting cellulose nanofibril’s high aspect ratio and nano-order-unit interconnected web-like structure of poplar wood, a new approach was designed. Steam explosion was used for the pretreatment of the poplar, followed by enzymatic hydrolysis assisted sonication for the preparation of nanocellulose. The effects the cellulase dosage, enzymatic hydrolysis time and temperature on the yield of nanocellulose were studied. Under optimal conditions nanocellulose yield was approximately 13.2%. The chemical composition, crystallinity, and morphology of the composites were characterised using FT-IR, x-ray diffraction and TEM. The results demonstrated that the structure was not destroyed during the preparation process, that the crystal form remained cellulose I, and the crystallinity was 61.98%, 9.15% higher than that of poplar cellulose. The width was between 20 and 50 nm, with high aspect ratio and a web-like entangled structure. Therefore, nanocellulose prepared using this method is an ideal toughening material that could be applied in composite materials.

Isolation and characterization of cellulose nanofibres from three common Nigerian grasses

Nanocellulose may be in nanocrystal or nanofibre form which may be extracted from purified cellulose by different methods. These include methods like dual-opposite-spinneret electrospinning, mechanical methods, a combination of chemical and mechanical methods, cryocrushing and enzymatic approaches. Nitrocelluloses have been extracted from various plants but not much has been reported on the yield from grasses. In this study, cellulose nanofibres (CNFs) were extracted from three common grasses; Pennisetum purpureum, Cynodon dactylon and Axonopus compressus by formic acid hydrolysis with the micrograph of CNF for each grass obtained. The CNFs are web-like long fibrous structure with diameter ranging between 3 to 5 nm and yield of over 75%. The crystallinity index averaged 76% and the onset temperature of thermal decomposition was 199 °C. Thus, Pennisetum purpureum, Cynodon dactylon and Axonopus compressus are good eco-friendly sources of CNF for potential application as new source of nanofillers for reinforcement of nanocomposite films.

A global production network for ecosystem services: The emergent governance of landscape restoration in the Brazilian Amazon

Over the last few decades, numerous initiatives have advanced forest landscape restoration in the Amazon, and in 2015 the Brazilian government set an ambitious, still-valid, target to restore 4.8 million hectares of degraded Amazonian land by 2030. This has contributed to an emergent global restoration network that connects multiple stakeholders and processes for funding, implementing and monitoring restoration actions in such a way that prepares various ecosystem services for market integration. The network arose in tandem with the evolution of an institutional framework that includes regulatory requirements within Brazil, global commitments linked to climate change mitigation, corporate sustainability strategies, and the growth of crowd-sourcing activism. This paper presents restoration activities as embedded within a Global Production Network (GPN) for an ecosystem service, which we use as a heuristic device to inform our understanding of emergent environmental governance structures. The resulting multi-scalar, networked mode of environmental governance is presented as a web-like structure co-created by institutional evolution, actor-specific strategies, and interactions between firms and non-firm actors. The article pays particular attention to a case study of how the restoration network manifests territorially in the Upper Xingu region of the Brazilian Amazon. Despite the strong North-South orientation of dominant funding relationships, network governance is also seen to be relational. This is evident from the dissemination of ideas, supply models and seeding techniques from Upper Xingu to other regions of Brazil. These insights could be applied to improve landscape restoration outcomes, and indeed the provisioning of ecosystem services more broadly.

Esterified cellulose nanofibres from saw dust using vegetable oil

In this work, cellulose nanofibres (CNFs) were extracted from sawdust, which is an underutilized by-product from the wood and timber industry. The extracted CNFs by chemical and mechanical treatments had a web-like structure with diameters ranging between 2 nm and 27 nm and lengths reaching a few microns. The obtained CNFs were further chemically modified with vegetable canola oil using two different esterification processes. In order to compare the effect of the surface modification of CNFs, the nanopapers were prepared from their prospective suspensions through solvent evaporation method, and then characterize with Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), thermogravimetric analysis (TGA), UV–vis spectroscopy and tensile tester. FTIR results indicated that both methods led to a successful grafting of the long chain hydrocarbon structure onto the CNFs, and became more hydrophobic when compared to unmodified CNFs-based nanopapers. The crystallinity, mechanical, light transmittance and thermal properties were significantly affected primarily by the esterification method employed, thus the degree of substitution. It was found that high degree of substitution adversely affected the crystallinity, light transmittance, mechanical and thermal properties. The crystallinity decreased from 70% to <40% when the degree of substation was about 0.8.

Enhanced Structure and Function of Stem Cell-Derived Beta-Like Cells Cultured on Extracellular Matrix

Differentiation of stem cells into insulin secreting beta-like cells holds great promise to treat diabetes. Current protocols drive the cells through stages of maturation and produce cells that secrete insulin. However, these cells still lack many of the characteristics of native beta cells. One important influence on native cell responses is the capillary basement membrane. Whether the stem cell-derived spheroids contain basement membrane and whether it plays any role in the cell responses is unknown. Here we show the spheroids do contain basement membrane proteins as a diffuse web-like structure. We demonstrate that the beta-like cells within the spheroid do not respond to this basement membrane and show no evidence for the cell polarization that characterizes native cells. We then isolated cells from the mature spheroids and show that culture on basement membrane protein coated dishes does impose cell polarity and favourably alters glucose dependent insulin secretion. We also show that cells cultured on the inner surface of basement membrane coated polymer devices survive implantation in a mouse and retain their identity. We conclude that the introduction of basement membrane and controlling the environment around stem cell-derived beta cells is a valuable route towards better phenocopying the native responses.

In-situ growth of CuO/Cu nanocomposite electrode for efficient CO2 electroreduction to CO with bacterial cellulose as support

Bacterial cellulose (BC) with large surface area and hydrophilic surface property is considered to be a good potential porous substrate for the deposition of active materials for catalysis, but lacks electrical conductivity for desired electrocatalysis application. By applying an in-situ chemical reduction, we here report a self-standing, BC-supported catalyst electrode of highly dispersed Cu and CuO nanocomposites (CuO/Cu4:3@BC) for catalyzing efficient CO2 electroreduction to CO. The inherent three-dimensional web-like porous structure of the BC substrate is sustained without further carbonization of the electrode. Compared to the conventional carbon paper-supported CuO/Cu composite catalysts, the as-prepared CuO/Cu4:3@BC electrode demonstrates an outstanding charge transport property and higher current density for CO2 reduction, owing to superiority of the web-like porous structure of the BC substrate with more accessible active sites to electrolytes and faster transfer of reactants and products. Therefore, the architecturally arranged CuO/Cu composite catalysts of the CuO/Cu4:3@BC electrode offer unique structural advantages of good ion and charge transport, promoting the catalytic kinetics for the conversion of CO2 to CO. The resulting electrode affords CO with a faradaic efficiency of 53 % at a small overpotential of 490 mV, and a durable activity over 40 h.

Durable superhydrophobic surface prepared by designing “micro-eggshell” and “web-like” structures

A durable superhydrophobic PVDF/FAC-SiO 2 /CNF coating with stable superhydrophobicity was prepared by designing “egg-shell” and “web-like” structures. Combined with the eggshell and web-like structure, the stable air cushion trapped on the PVDF/FAC-SiO 2 /CNF SHC surface can provide excellent hydrophobic stability, even for slurry, hot water or 98% H 2 SO 4 . • A novel superhydrophobic coating was successfully prepared by designing ‘micro-eggshell’ and ‘web-like’ structures. • The locked gas of “egg-shell” and “web-like” can enhance the hydrophobic stability of the coating surface. • The PVDF/FAC-SiO 2 /CNF coating can withstand hot water immersion or 98% H 2 SO 4 dumped. • The prepared coating possesses high charge transfer resistance (1.44 × 10 10 Ω cm 2 ) after 30 d immersion. Superhydrophobic surfaces (SHSs) have drawn a lot of interest in both academic and industry by its special wettability, but most artificial SHSs suffer from their poor hydrophobic and mechanical durability. Here, a durable PVDF/FAC-SiO 2 /CNF superhydrophobic coating (SHC) was successfully fabricated by designing “egg-shell” and “web-like” structures. We have in situ loaded nano-SiO 2 particles on the azodicarbonamide (AC) surface to provide a layer of barrier, which can prompt the formation of a special egg-shell structure after AC thermal decomposition. Moreover, CNF divided the pore structure to smaller spaces by forming web-like structure in the coating surface. Cooperation of the egg-shell and web-like structures, the PVDF/FAC-SiO 2 /CNF SHC surface can lock the gas stably and block the diffusion of corrosive media into the coating. Therefore, the prepared PVDF/FAC-SiO 2 /CNF coating can withstand 250 kPa water flow impact and possesses high charge transfer resistance (1.44 × 10 10 Ω cm 2 ) after 30 d immersion in 3.5 wt% NaCl solution. Furthermore, the prepared coating also exhibited outstanding mechanical and hydrophobic stability, which can maintain its superhydrophobicity even after 1000 abrasion cycles, hot water immersion, or dealing with 98% H 2 SO 4 . This fabrication process is scalable and provides a new avenue for the fabrication of robust superhydrophobic coatings.

In vitro characterization of root extracellular trap and exudates of three Sahelian woody plant species.

Arabinogalactan protein content in both root extracellular trap and root exudates varies in three Sahelian woody plant species that are differentially tolerant to drought. At the root tip, mature root cap cells, mainly border cells (BCs)/border-like cells (BLCs) and their associated mucilage, form a web-like structure known as the "Root Extracellular Trap" (RET). Although the RET along with the entire suite of root exudates are known to influence rhizosphere function, their features in woody species is poorly documented. Here, RET and root exudates were analyzed from three Sahelian woody species with contrasted sensitivity to drought stress (Balanites aegyptiaca, Acacia raddiana and Tamarindus indica) and that have been selected for reforestation along the African Great Green Wall in northern Senegal. Optical and transmission electron microscopy show that Balanites aegyptiaca, the most drought-tolerant species, produces only BC, whereas Acacia raddiana and Tamarindus indica release both BCs and BLCs. Biochemical analyses reveal that RET and root exudates of Balanites aegyptiaca and Acacia raddiana contain significantly more abundant arabinogalactan proteins (AGPs) compared to Tamarindus indica, the most drought-sensitive species. Root exudates of the three woody species also differentially impact the plant soil beneficial bacteria Azospirillum brasilense growth. These results highlight the importance of root secretions for woody species survival under dry conditions.

Protease Activity in Vascular Disease.

Protease Activity in Vascular Disease.