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Nature Communications Jul 2023In ferroelectrics, complex interactions among various degrees of freedom enable the condensation of topologically protected polarization textures. Known as ferroelectric...
In ferroelectrics, complex interactions among various degrees of freedom enable the condensation of topologically protected polarization textures. Known as ferroelectric solitons, these particle-like structures represent a new class of materials with promise for beyond-CMOS technologies due to their ultrafine size and sensitivity to external stimuli. Such polarization textures have scarcely been demonstrated in multiferroics. Here, we present evidence for ferroelectric solitons in (BiFeO)/(SrTiO) superlattices. High-resolution piezoresponse force microscopy and Cs-corrected high-angle annular dark-field scanning transmission electron microscopy reveal a zoo of topologies, and polarization displacement mapping of planar specimens reveals center-convergent/divergent topological defects as small as 3 nm. Phase-field simulations verify that some of these structures can be classed as bimerons with a topological charge of ±1, and first-principles-based effective Hamiltonian computations show that the coexistence of such structures can lead to non-integer topological charges, a first observation in a BiFeO-based system. Our results open new opportunities in multiferroic topotronics.
Topics: Bismuth; Microscopy, Atomic Force; Technology
PubMed: 37443322
DOI: 10.1038/s41467-023-39841-3 -
PloS One 20233D printing technology is gradually considered to be a rapid development of a green revolution in the field of architecture. Recently, utilizing solid mine waste to...
3D printing technology is gradually considered to be a rapid development of a green revolution in the field of architecture. Recently, utilizing solid mine waste to replace natural sand not only greatly reduces the 3D printing costs, but also contributes to an environmental sustainability development. However, most solid waste inevitably has an impact on the inherent mechanical strength and printability of concrete materials. It is an urgent requirement to expand the alternative materials and improve the overall property of 3D concrete materials. This paper reported an innovative concrete material that replaced natural sand with fine limestone powders for 3D concrete printing applications. The experimental measurements were performed including microstructures characteristics, flowability, buildability, shrinkability, layer-interface properties, mechanical properties and interlayer bonding strength. Besides, an effective method was proposed to characterize the printable properties of concrete materials and then the reasonable limestone powder replacement ratio was determined. Based on the investigation results, appropriate substituting limestone powder (40%) can effectively improve the grading of the concrete, thus promoting its printability and buildability. Moreover, the microstructures of the 3D printing concrete materials after curing were denser and their mechanical property improved by approximately 45%. With the further increase of replacement ratio, the reduction in the flowability led to a decrease of the printability. A large number of fine particles increased the shrinkage of the curing process and some bubbles were stranded inside the materials due to its increase in the viscosity, thereby reducing the mechanical properties of the hardened material. The produced concrete for 3D printing can be treated as an eco-friendly building material that contributes to the rational development and resource utilization of solid water, thus promoting the sustainable development of construction field.
Topics: Sand; Powders; Construction Materials; Printing, Three-Dimensional; Calcium Carbonate
PubMed: 37856432
DOI: 10.1371/journal.pone.0292951 -
Scientific Reports Apr 2024An essential research area for scientists is the development of high-performing, inexpensive, non-toxic antibacterial materials that prevent the transfer of bacteria. In...
An essential research area for scientists is the development of high-performing, inexpensive, non-toxic antibacterial materials that prevent the transfer of bacteria. In this study, pure BiWO and BiWO/MWCNTs nanocomposite were prepared by hydrothermal method. A series of characterization results by using XRD FTIR, Raman, FESEM, TEM, and EDS analyses, reveal the formation of orthorhombic nanoflakes BiWO by the addition of NaOH and pH adjustment to 7. Compared to pure BiWO, the BiWO/MWCNTs nanocomposite exhibited that CNTs are efficiently embedded into the structure of BiWO which results in charge transfer between metal ion electrons and the conduction or valence band of BiWO and MWCNTs and result in shifting to longer wavelength as shown in UV-visible and PL. The results confirmed that MWCNTs are stuck to the surface of the microflowers, and some of them embedded inside the BiWO nanoflakes without affecting the structure of BiWO nanoflakes as demonstrated by TEM. In addition, Pure BiWO and the BiWO/MWCNTs nanocomposite were tested against P. mirabilis and S. mutans., confirming the effect of addition MWCNTs materials had better antibacterial activity in opposition to both bacterial strains than pure BiWO. Besides, pure BiWO and the BiWO/MWCNTs nanocomposite tested for cytotoxicity against lung MTT test on Hep-G2 liver cancer cells, and flow-cytometry. Results indicated that pure BiWO and the BiWO/MWCNTs nanocomposite have significant anti-cancer efficacy against Hep-G2 cells in vitro. In addition, the findings demonstrated that BiWO and BiWO/MWCNTs triggered cell death via increasing ROS. Based on these findings, it appears that pure BiWO and the BiWO/MWCNTs nanocomposite have the potential to be developed as nanotherapeutics for the treatment of bacterial infections, and liver cancer.
Topics: Nanocomposites; Anti-Bacterial Agents; Humans; Antineoplastic Agents; Bismuth; Tungsten Compounds; Nanotubes, Carbon; Microbial Sensitivity Tests; Cell Survival; Hep G2 Cells
PubMed: 38664493
DOI: 10.1038/s41598-024-58751-y -
Vaccine Sep 2023The spike (S) protein of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a glycoprotein, expressed on the virion surface, that mediates infection of host...
The spike (S) protein of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a glycoprotein, expressed on the virion surface, that mediates infection of host cells by directly interacting with host receptors. As such, it is a reasonable target to neutralize the infectivity of the virus. Here we found that a recombinant S protein vaccine adjuvanted with Alhydrogel or the QS-21-like adjuvant Quil-A effectively induced anti-S receptor binding domain (RBD) serum IgG and neutralizing antibody titers in the Syrian hamster model, resulting in significantly low SARS-CoV-2 replication in respiratory organs and reduced body weight loss upon virus challenge. Severe lung inflammation upon virus challenge was also strongly suppressed by vaccination. We also found that the S protein vaccine adjuvanted with Alhydrogel, Quil-A, or an AS03-like adjuvant elicited significantly higher neutralizing antibody titers in mice than did unadjuvanted vaccine. Although the neutralizing antibody titers against the variant viruses B.1.351 and B.1.617.2 declined markedly in mice immunized with wild-type S protein, the binding antibody levels against the variant S proteins were equivalent to those against wild-type S. When splenocytes from the immunized mice were re-stimulated with the S protein in vitro, the induced Th1 or Th2 cytokine levels were not significantly different upon re-stimulation with wild-type S or variant S, suggesting that the T-cell responses against the variants were the same as those against the wild-type virus. Upon Omicron XBB-challenge in hamsters, wild-type S-vaccination with Alhydrogel or AS03 reduced lung virus titers on Day 3, and the Quil-A adjuvanted group showed less body weight loss, although serum neutralizing antibody titers against XBB were barely detected in vitro. Collectively, recombinant vaccines coupled with different adjuvants may be promising modalities to combat new variant viruses by inducing various arms of the immune response.
Topics: Cricetinae; Animals; Humans; Mice; SARS-CoV-2; Aluminum Hydroxide; Spike Glycoprotein, Coronavirus; COVID-19; Adjuvants, Immunologic; Vaccines, Synthetic; Mesocricetus; Antibodies, Neutralizing; Weight Loss
PubMed: 37635002
DOI: 10.1016/j.vaccine.2023.08.054 -
Scientific Reports Aug 2023By roughly mimicking the surface architectural design of dragonfly wings, novel bi-phasic 3D nanoflowers of MgO/Mg(OH) were successfully synthesized via the...
By roughly mimicking the surface architectural design of dragonfly wings, novel bi-phasic 3D nanoflowers of MgO/Mg(OH) were successfully synthesized via the electrospinning technique. The 3D nanoflowers were coated over a commercial melamine sponge and extensively characterized by SEM, XRD, FTIR, and EDS. The formation of distinct dense 3D nano petals was revealed by SEM images whereby the mean petal thickness and mean distance between the adjacent petals were found to be 36 nm and 121 nm, respectively. The bactericidal activities of synthesized 3D nano-flowers coated melamine sponges were assessed against five different bacteria (Staphylococcus aureus, Enterococcus faecalis, Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa). This study demonstrated significant bactericidal activity of MgO/Mg(OH) 3D nanoflowers coated MS against Gram-positive and Gram-negative bacteria. Plausible bactericidal mechanisms include envelope deformation, penetration, and induction of oxidative stress. This study introduces novel bioinspired biomaterial with the capacity to reduce the risk associated with pathogenic bacterial infections, especially in medical devices.
Topics: Animals; Magnesium Oxide; Anti-Bacterial Agents; Odonata; Gram-Negative Bacteria; Gram-Positive Bacteria; Escherichia coli
PubMed: 37587205
DOI: 10.1038/s41598-023-40336-w -
The Science of the Total Environment Oct 2023Using the biomimetic process known as microbially induced calcium carbonate precipitation (MICP), the growth of bio-tiles was investigated as an alternative to...
Using the biomimetic process known as microbially induced calcium carbonate precipitation (MICP), the growth of bio-tiles was investigated as an alternative to conventionally fired ceramic tiles which require operating temperatures above 1000 °C, therefore adding to global carbon emissions. The ureolytic activity of Sporosarcina pasteurii was controlled by centrifuging and dilution with fresh yeast extract media. The bio-tiles were grown using a novel submersion method in which custom moulds were placed in exact positions within the bio-reactor and each was mixed individually from beneath. Five parameters were optimised to achieve bio-tiles (dimensions of 100 × 100 × 10 mm) of breaking strength comparable to conventional tiles of equivalent thickness. By optimising ureolytic activity (4.0 mmol/L·min), the cementation solution concentration (0.3 M), the particle size distribution (D = 312 μm; D = 469 μm), the volume of cementation solution, as well as the addition of supplemental magnesium (0.3 M), bio-tiles with a breaking strength 637 N ± 60 N and a modulus of rupture of 13.0 N/mm ± 2.3 N were produced. These parameters exceed the conventional standards of breaking strength and modulus of rupture of 600 N and 8 N/mm, respectively, the standards set for tiles with a water absorption above 10 %. This is also the first time that an optimum CaCO precipitation rate constant has been identified (0.11-0.18 day) for producing bio-tiles that meet the strength properties of conventional extruded ceramic tiles. The tile manufacturing technique described in this study is easy to operate and scale since multiple bio-tiles can be produced in larger cementation tanks. This natural tile making process also benefits the environment by operating at room temperature.
Topics: Calcium Carbonate; Urea; Temperature; Water; Chemical Precipitation
PubMed: 37355135
DOI: 10.1016/j.scitotenv.2023.165050 -
BMC Oral Health Oct 2023Zein-coated magnesium oxide nanoparticles (zMgO NPs) demonstrate a potent antimicrobial effect, endorsing it as a compelling additive to dental materials formulations...
BACKGROUND
Zein-coated magnesium oxide nanoparticles (zMgO NPs) demonstrate a potent antimicrobial effect, endorsing it as a compelling additive to dental materials formulations for oral health care advances. However, currently there is no data on the imprint of zMgO NPs on the color permanence of dental composites. The objective of this study is to evaluate the color stability of different types of composite enhanced with antimicrobial zein-coated magnesium oxide nanoparticles (zMgO NPs) of different shapes before and after thermocycling.
METHODS
Two hundred composite samples were divided into four groups: Gp1: Tetric N-Flow with zMgO nanowires, Gp2: Tetric N-Flow with zMgO nanospheres, Gp3: Tetric N-Ceram with zMgO nanowires; Gp4: Tetric N-Ceram with zMgO nanospheres. Each group was subdivided into 5 subgroups (n = 10) with concentrations of zMgO NPs 0%, 0.3%, 0.5%, 1% and 2%. The characterization of the modified composite containing the zMgO was done via X-ray Diffraction, Field Emission Scanning Electron Microscopy (FESEM), and Fourier Transform Infrared Spectroscopy (FTIR). Colorimetric evaluation was performed through spectrophotometry with a white background. Samples underwent color assessment using a spectrophotometer, followed by thermocycling, and then another color assessment.
RESULTS
FESEM analysis showed a uniform distribution of the zMgO nanoparticles in the composite and FTIR illustrated no change in the spectra. However, the XRD spectra exhibited an amorphous pattern in the composite enhanced with zMgO NPs. There was no compelling discrepancy in color variation ΔE among the different groups before and after thermocycling (p > 0.05). A statistically notable variation in ΔL was found amid the control and N-Flow and N-Ceram with 2% zMgO nanospheres before and after thermocycling respectively (p < 0.05). While after thermocycling, there was a statistically significant difference in Δa in N-Flow and N-Ceram wires amid the control and the different groups (p < 0.05). Additionally, after thermocycling there was a statistically significant difference in Δb in N-Flow and N-Ceram wires between the control and the different groups (p < 0.05). The Tukey test exhibited no variation among the groups with different zMgO concentrations (p > 0.05).
CONCLUSION
Enhancing N-Flow and N-Ceram composite with antimicrobial zMgO nanowires and nanospheres did not alter the total color stability of the materials before and after thermocycling.
Topics: Humans; Magnesium Oxide; Zein; Color; Composite Resins; Anti-Infective Agents; Nanoparticles; Materials Testing; Surface Properties
PubMed: 37858112
DOI: 10.1186/s12903-023-03495-w -
Biomaterials Advances Oct 2023Breast cancer is resistant to conventional treatments due to the specific tumour microenvironment, the associated acidic pH and the overexpression of receptors that...
Breast cancer is resistant to conventional treatments due to the specific tumour microenvironment, the associated acidic pH and the overexpression of receptors that enhance cells tumorigenicity. Herein, we optimized the synthesis of acidic resorbable calcium carbonate (CaCO) nanoparticles and the encapsulation of a low molecular weight model molecule (Rhodamine). The addition of ethylene glycol during the synthetic process resulted in a particle size decrease: we obtained homogeneous CaCO particles with an average size of 564 nm. Their negative charge enabled the assembly of layer-by-layer (LbL) coatings with surface-exposed hyaluronic acid (HA), a ligand of tumour-associated receptor CD44. The coating decreased Rhodamine release by two-fold compared to uncoated nanoparticles. We demonstrated the effect of nanoparticles on two breast cancer cell lines with different aggressiveness - SK-BR-3 and the more aggressive MDA-MB-231 - and compared them with the normal breast cell line MCF10A. CaCO nanoparticles (coated and uncoated) significantly decreased the metabolic activity of the breast cancer cells. The interactions between LbL-coated nanoparticles and cells depended on HA expression on the cell surface: more particles were observed on the surface of MDA-MB-231 cells, which had the thickest endogenous HA coating. We concluded that CaCO nanoparticles are potential candidates to carry low molecular weight chemotherapeutics and deliver them to aggressive breast cancer sites with an HA-abundant pericellular matrix.
Topics: Humans; Female; Breast Neoplasms; Calcium Carbonate; MCF-7 Cells; Rhodamines; Nanoparticles; Tumor Microenvironment
PubMed: 37487456
DOI: 10.1016/j.bioadv.2023.213563 -
Ecotoxicology and Environmental Safety Nov 2023Mechanochemistry and photocatalysis are emergent technologies for the remediation of polycyclic aromatic hydrocarbons (PAHs) in soils. In this work, mechanochemistry and...
Mechanochemistry and photocatalysis are emergent technologies for the remediation of polycyclic aromatic hydrocarbons (PAHs) in soils. In this work, mechanochemistry and photocatalysis are combined for pyrene degradation. The photodegradation of pyrene, when in contact with sepiolite under pressure application, is studied. The mechanical treatment leads to a pyrene crystal phase transformation. In this new phase, pyrene undergoes a fast photodegradation in the 320-420 nm range. We show that sepiolite is superior as a photocatalyst in pyrene degradation to TiO, the most exploited photocatalyst. A broad physicochemical characterization is carried out to propose a mechanism in which the photoexcitation of mechanically altered pyrene leads to an electron transfer to sepiolite matrix, which triggers the PAH degradation. Finally, we want to highlight that the pyrene/sepiolite combination is a simplified system to shed light on how PAH photodegradation may occur in soils.
Topics: Photolysis; Polycyclic Aromatic Hydrocarbons; Pyrenes; Light; Soil
PubMed: 37856983
DOI: 10.1016/j.ecoenv.2023.115573 -
Scientific Reports Oct 2023A new bismuth-based CT agent was synthesized through a facile synthesis strategy. The in vitro stability, toxicity and CT performance were evaluated. The in vivo imaging...
A new bismuth-based CT agent was synthesized through a facile synthesis strategy. The in vitro stability, toxicity and CT performance were evaluated. The in vivo imaging performance was investigated using three different doses (0.5, 1.2 and 5 mmol/kg) and the result obtained at 1.2 mmol/kg was compared with the clinically approved CT agent iopamidol at the same dosage.
Topics: Contrast Media; Tomography, X-Ray Computed; Bismuth
PubMed: 37798332
DOI: 10.1038/s41598-023-43031-y