Synthesis of CaCO3 supported nano zero-valent iron-nickel nanocomposite (nZVI-Ni@CaCO3) and its application for trichloroethylene removal in persulfate activated system.

Nano zero-valent (nZVI) based composite have been widely utilized in environmental remediation. However, the rapid agglomeration and quick deactivation of nZVI limited its application on large scale. In this work, CaCO3 supported nZVI-Ni catalyst, namely nZVI-Ni@CaCO3 was prepared and used for the efficient removal of trichloroethylene (TCE) in PS oxidation process. The successful disbursement of nZVI-Ni on CaCO3 support material not only increased the surface area of nZVI-Ni@CaCO3 (69.45 m2/g) with respect to CaCO3 (5.92 m2/g) and bare nZVI (13.29 m2/g) but also improved the catalytic activity. XRD, XPS and FTIR analysis confirmed the successful formation of nZVI-Ni@CaCO3 nanoparticles. The nZVI-Ni@CaCO3 nanoparticles combined with PS had achieved complete removal of TCE (99.8%) with dosage of 36 mg/L and 1.34 mM respectively. These results showed that the use of CaCO3 as support material for nZVI-Ni could have significant influence on contaminant removal process. Scavenging and EPR tests validated the existence of SO4•-, OH• and O2•- radicals in PS/nZVI-Ni@CaCO3 system and highlighted the dominant role of SO4•- radicals in TCE removal process. HCO3- ions and humic acid have shown adverse effect on TCE removal due to radical scavenging and buffering effect. Owing to improved catalytic activity and easy preparation, the nZVI-Ni@CaCO3 nanoparticles could be served as an alternative strategy for environmental remediation.

Rheology of graphene oxide stabilized Pickering emulsions.

Pickering emulgels stabilized by graphene oxide (GO) with didodecyldimethylammonium bromide (DDAB) as an auxiliary surfactant and liquid paraffin as the oil phase have proved to be an excellent 3D printable ink. This paper elucidates the structure of such emulgels by a combination of microscopy before and after intensive shear as well as broadband dielectric spectroscopy and rheology in the linear and nonlinear regime. An increase of the DDAB surfactant and GO-contents leads to a systematic increase of modulus and viscosity, a reduction of the limits of the nonlinear regime and a more complicated variation of the normal forces, with negative normal forces at high shear rate  for low GO-contents and positive normal forces at high GO-contents. The interfacial jamming behavior studied by morphology, rheology and dielectric spectroscopy is explained based on droplet deformation, jamming and recovery phenomena.

Understanding Gel-Powers: Exploring Rheological Marvels of Acrylamide/Sodium Alginate Double-Network Hydrogels.

This study investigates the rheological properties of dual-network hydrogels based on acrylamide and sodium alginate under large deformations. The concentration of calcium ions affects the nonlinear behavior, and all gel samples exhibit strain hardening, shear thickening, and shear densification. The paper focuses on systematic variation of the alginate concentration-which serves as second network building blocks-and the Ca2+-concentration-which shows how strongly they are connected. The precursor solutions show a typical viscoelastic solution behavior depending on alginate content and pH. The gels are highly elastic solids with only relatively small viscoelastic components, i.e., their creep and creep recovery behavior are indicative of the solid state after only a very short time while the linear viscoelastic phase angles are very small. The onset of the nonlinear regime decreases significantly when closing the second network (alginate) upon adding Ca2+, while at the same time the nonlinearity parameters (Q0, I3/I1, S, T, e3/e1, and v3/v1) increase significantly. Further, the tensile properties are significantly improved by closing the alginate network by Ca2+ at intermediate concentrations.

High Dielectric Poly(vinylidene fluoride)-Based Polymer Enables Uniform Lithium-Ion Transport in Solid-State Ionogel Electrolytes.

Ionic liquids (ILs)-incorporated solid-state polymer electrolytes (iono-SPEs) have high ionic conductivities but show non-uniform Li+ transport in different phases. This work greatly promotes Li+ transport in polymer phases by employing a poly (vinylidene fluoride-trifluoroethylene-chlorotrifluoroethylene) [P(VDF-TrFE-CTFE), PTC] as the framework of ILs to prepare iono-SPEs. Unlike PVDF, PTC with suitable polarity shows weaker adsorption energy on IL cations, reducing their possibility of occupying Li+ -hopping sites. The significantly higher dielectric constant of PTC than PVDF facilitates the dissociation of Li-anions clusters. These two factors motivate Li+ transport along PTC chains, narrowing the difference in Li+ transport among varied phases. The LiFePO4 /PTC iono-SPE/Li cells cycle steadily with capacity retention of 91.5 % after 1000 cycles at 1 C and 25 °C. This work paves a new way to induce uniform Li+ flux in iono-SPEs through polarity and dielectric design of polymer matrix.

Surface Tension of the Oxide Skin of Gallium-Based Liquid Metals.

Gallium-based alloys have garnered considerable attention in the scientific community, particularly as they are in an atypical liquid state at and near room temperature. Though physical parameters, such as thermal conductivity, electrical conductivity, viscosity, yield stress, and surface tension, of these alloys are broadly known, the surface tension (surface free energy) of the oxide skin remains intangible due to the high yield stress of the oxide skin. In this article, we propose to employ gradually attenuated vibrations to obtain equilibrium shapes, which are analyzed along the lines of the puddle height method. The surface tension of the oxide skin was determined on quartz glass and liquid metal-phobic diamond coating to be around 350-365 mN/m, thus independent of the substrate surface or employed liquid metal (i.e., eutectic Ga-In (EGaIn) and galinstan). The similarity of the surface tension for different alloys was ascribed to the composition of the oxide skin, which predominantly comprises gallium oxides due to thermodynamic constraints. We envision that this method can also be applied to other liquid metal alloys and liquid metal marble systems facilitating modeling, simulation, and optimization processes.

Utilization of Ag2O-Al2O3-ZrO2 decorated onto rGO as adsorbent for the removal of Congo red from aqueous solution.

The water resources contamination in an alarming concern for sustainable environment. This has led to development of new technologies and materials for waste water detoxification. In the present study, we have fabricated novel trimetallic based mixed oxides decorated reduced graphene oxide (rGO) composite using facile microwave method and utilized it as an adsorbent for the removal of congo red dye from aqueous solution. The final composite showed highly agglomerated metal oxides present on the rGO surface. The high surface area and activity of the synthesized adsorbent resulted in its high adsorption capacity of 333.32 mg/g for congo red. The Langmuir model better explained the isotherm data indicating the monolayer adsorption of congo red molecules onto Ag2O-Al2O3-ZrO2/rGO surface. The grander adsorption ability of Ag2O-Al2O3-ZrO2/rGO towards organic dye indicate its probable utilization in the removal of other dyes also from wastewater.

HA-coated collagen nanofibers for urethral regeneration via in situ polarization of M2 macrophages.

In situ tissue engineering utilizes the regenerative potential of the human body to control cell function for tissue regeneration and has shown considerable prospect in urology. However, many problems are still to be understood, especially the interactions between scaffolds and host macrophages at the wound site and how these interactions direct tissue integration and regeneration. This study was designed to evaluate the efficacy of hyaluronic acid (HA) functionalized collagen nanofibers in modulating the pro-healing phenotype expression of macrophages for urethral regeneration. Tubular HA-collagen nanofibers with HA-coating were prepared by coaxial electrospinning. The formation of a thin HA-coating atop each collagen nanofiber endowed its nanofibrous mats with higher anisotropic wettability and mechanical softness. The macrophages growing on the surface of HA-collagen nanofibers showed an elongated shape, while collagen nanofibers' surface exhibited a pancake shape. Immunofluorescence and ELISA analysis showed that elongation could promote the expression of M2 phenotype marker and reduce the secretion of inflammatory cytokines. In vivo experiments showed that tubular HA-collagen nanofibers significantly facilitate male puppy urethral regeneration after injury. In the regenerated urethra bridged by tubular HA-collagen nanofibers, anti-inflammatory M2 macrophages are recruited to the surface of the scaffold, which can promote angiogenesis and endogenous urothelial progenitor cell proliferation.

Study of the Interactions of Zwitterions and Carbon Nanotubes by Nonlinear Rheology in an Aqueous Environment.

Aqueous nanocomposite solutions of P(NIPAM) and P(NIPAM- co- N-(3-Sulfopropyl)- N-(methacryloxyethyl)- N,N-dimethylammonium betaine), a zwitterionic monomer with carbon nanotubes (CNT) as filler, were synthesized and characterized rheologically. While the influence of P(NIPAM) content and CNT content can be considered to be relatively minor, the introduction of a zwitterionic monomer (Zw) into the polymer leads to clear rheological traces of strong interactions between zwitterionic moieties and surface moieties on the CNTs, namely, a significantly lower nonlinearity limit and a lower modulus at high Zw contents and a higher modulus at intermediate contents due to adsorption of zwitterionic moieties on the CNT surface as well as a significantly lengthened time for the sample to adjust itself to the applied deformation, suggesting that the adsorbed polymer chains need to reorganize themselves significantly to accommodate to the applied strain γ0.

Biomechanical Heterogeneity of Living Cells: Comparison between Atomic Force Microscopy and Finite Element Simulation.

Atomic force microscopy (AFM) indentation is a popular method for characterizing the micromechanical properties of soft materials such as living cells. However, the mechanical data obtained from deep indentation measurements can be difficult and problematic to interpret as a result of the complex geometry of a cell, the nonlinearity of indentation contact, and constitutive relations of heterogeneous hyperelastic soft components. Living MDA-MB-231 cells were indented by spherical probes to obtain morphological and mechanical data that were adopted to build an accurate finite element model (FEM) for a parametric study. Initially, a 2D-axisymmetric numerical model was constructed with the main purpose of understanding the effect of geometrical and mechanical properties of constitutive parts such as the cell body, nucleus, and lamellipodium. A series of FEM deformation fields were directly compared with atomic force spectroscopy in order to resolve the mechanical convolution of heterogeneous parts and quantify Young's modulus and the geometry of nuclei. Furthermore, a 3D finite element model was constructed to investigate indentation events located far from the axisymmetric geometry. In this framework, the joint FEM/AFM approach has provided a useful methodology and a comprehensive characterization of the heterogeneous structure of living cells, emphasizing the deconvolution of geometrical structure and the true elastic modulus of the cell nucleus.

Visible photodegradation of ibuprofen and 2,4-D in simulated waste water using sustainable metal free-hybrids based on carbon nitride and biochar.

Rational designing of metal-free carbon nitride based photocatalysts can lead to an excellent optical response and a higher photocatalytic activity driven by visible and solar light. This combines green photocatalytic technology with greener materials prepared by facile approaches for environmental remediation. Herein we report utilization of star photocatalyst g-C3N4 (CN) to form highly efficient hetero-assemblies along with acidified g-C3N4 (ACN), polyaniline (PANI), reduced graphene oxide (RGO) and biochar. By use of these organic semiconductors we synthesize g-C3N4/ACN/RGO@Biochar (GARB), g-C3N4/PANI/RGO@Biochar (GPRB) and ACN/PANI/RGO@Biochar (APRB) nano-assemblies with different optical response and band edge positions for a better charge flow and reduced recombination of carriers. These synthesized catalysts were used for visible light powered degradation of 2,4-Dichlorophenoxy acetic acid (2,4-D) and ibuprofen (IBN). APRB performs the best and degrades 99.7% and 98.4% of 2,4-D and IBN (20 mg L-1) under Xe lamp exposure in 50 min and retention of high activity in natural sunlight. Optical analysis, photoelectrochemical response and radical quenching studies show both hydroxyl and superoxide radical anions as major reactive species and a Z-scheme photocatalytic mechanism. RGO acts as an electron mediator and protects higher positioned bands of PANI and ACN in APRB for a remarkable photocatalytic activity for a metal free material. The degradation pathway was analyzed by LC-MS analysis and 42% and 40% total organic carbon was removed in 2 h for 2,4-D and IBN degradation respectively. The toxicity of degraded products was analyzed by analyzing viability of human peripheral blood cells with retaining of 99.1% cells.

Viscoelastic Conjugated Polymer Fluids.

The introduction of optoelectronic functions into viscoelastic polymers can yield highly sophisticated soft materials for biomedical devices and autonomous robotics. However, viscoelasticity and excellent optoelectronic properties are difficult to achieve because the presence of a large number of π-conjugated moieties drastically stiffens a polymer. Here, we report a variation of additive-free viscoelastic conjugated polymers (VE-CPs) at room temperature by using an intact π-conjugated backbone and bulky, yet flexible, alkyl side chains as "internal plasticizers." Some of these polymers exhibit gel- and elastomer-like rheological behaviors without cross-linking or entanglement. Furthermore, binary blends of these VE-CPs exhibit a never-seen-before dynamic miscibility with self-restorable and mechanically induced fluorescence color changes.

Durable Antibacterial and Nonfouling Cotton Textiles with Enhanced Comfort via Zwitterionic Sulfopropylbetaine Coating.

A rapid, environment-friendly, and cost-effective finishing method has been developed for cotton textiles by using zwitterionic NCO-sulfopropylbetaine as the antibacterial finishing agent through covalent bond. The sulfopropylbetaine-finished cotton textile exhibits durable broad-spectrum antibacterial and nonfouling activity, improved mechanical properties, and enhanced comfort.

Kinin B1 receptor blockade and ACE inhibition attenuate cardiac postinfarction remodeling and heart failure in rats.

INTRODUCTION: The aim of the present study was to evaluate the effects of the novel kinin B1 receptor antagonist BI113823 on postinfarction cardiac remodeling and heart failure, and to determine whether B1 receptor blockade alters the cardiovascular effects of an angiotensin 1 converting enzyme (ACE) inhibitor in rats. METHODS AND RESULTS: Sprague Dawley rats were subjected to permanent occlusion of the left coronary artery. Cardiovascular function was determined at 6weeks postinfarction. Treatment with either B1 receptor antagonist (BI113823) or an ACE inhibitor (lisinopril) alone or in combination significantly reduced the heart weight-to-body weight and lung weight-to-body weight ratios, and improved postinfarction cardiac function as evidenced by greater cardiac output, the maximum rate of left ventricular pressure rise (±dP/dtmax), left ventricle ejection fraction, fractional shorting, better wall motion, and attenuation of elevated left ventricular end diastolic pressure (LVEDP). Furthermore, all three treatment groups exhibited significant reduction in cardiac interstitial fibrosis, collagen deposition, CD68 positive macrophages, neutrophils, and proinflammatory cytokine production (TNF-α and IL-1ß), compared to vehicle controls. CONCLUSION: The present study shows that treatment with the novel kinin B1 receptor antagonist, BI113823, reduces postinfarction cardiac remodeling and heart failure, and does not influence the cardiovascular effects of the ACE inhibitor.

Nanoprecursor-Mediated Synthesis of Mg²âº-Doped TiO2 Nanoparticles and Their Application for Dye-Sensitized Solar Cells.

Surface-doping anatase TiO2 nanoparticles with Mg²âº were prepared via a novel synthetic method, and used as photoanodes for dye-sensitized solar cells (DSSCs). X-ray powder diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) image results indicate that the Mg²âº doping has no effect on the crystal phase and morphology of anatase TiO2. The shift in XRD peaks to higher angles, the absorption shift in UV-vis diffuse reflection spectra, and X-ray photoelectron spectroscopy (XPS) results indicate the incorporation of Mg²âº-ions into the TiO2 lattice. The as-prepared TiO2nanoparticles doped with a low concentration of ions is proven a superior photoanode material than pure anatase TiO2. The energy-conversion efficiency (1) of DSSC based on TiO2 nanoparticles doped with Mg²âº is at a maximum of 5.90%, corresponding to an efficiency improvement of 23.4% as compared to DSSC based on un-doped TiO2. This new synthetic approach using a nanoprecursor provides a simple and versatile method for the preparation of excellent photoanode materials for application in solar energy conversion devices.

Oscillations in modulus in solutions of graphene oxide and reduced graphene oxide with grafted poly-N-isopropylamide.

In a material consisting of graphene oxide or reduced graphene oxide and poly-N-isopropylamide (PNIPAM) in an aqueous solution, a new type of rheological behaviour is found. When subjecting the material to a short and relatively small deformation pulse, the modulus, which is observed by small deformations in the linear-viscoelastic or very slightly nonlinear range, oscillates with periodicities between 100 and several 1000 seconds; however, in many cases, it also increases systematically. The periodicity depends on the filler content and the sample preparation method (in situ polymerisation vs. blending). When subjecting the material to high nonlinear deformations (γ0 = 100-300%), the resulting linear viscoelastic behaviour changes from a periodic oscillation to a quick recovery of the original data, followed by a decrease and a subsequent increase beyond the value of the modulus of the material prior to the deformation pulse.

Hydrogen bonding in aprotic solvents, a new strategy for gelation of bioinspired catecholic copolymers with N-isopropylamide.

Copolymers of N-isopropylacrylamide (NIPAM) and dopamine methacrylate can establish a reversible, self-healing 3D network in aprotic solvents based on hydrogen bonding. The reactivity and hydrogen bonding formation of catechol groups in copolymer chains are studied by UV-vis and (1) H NMR spectroscopy, while reversibility from sol to gel and inverse as well as self-healing properties are tested rheologically. The produced reversible organogel can self-encapsulate physically interacting or chemically bonded solutes such as drugs due to thermosensitivity of the used copolymer. This system offers dual-targeted and controlled drug delivery and release-by slowing down release kinetics by supramolecular bonding of the drug and by reducing diffusion rates due to modulus increase.

Graphene oxide/carbon nanotube composite hydrogels-versatile materials for microbial fuel cell applications.

Carbonaceous nanocomposite hydrogels are prepared with an aid of a suspension polymerization method and are used as anodes in microbial fuel cells (MFCs). (Poly N-Isopropylacrylamide) (PNIPAM) hydrogels filled with electrically conductive carbonaceous nanomaterials exhibit significantly higher MFC efficiencies than the unfilled hydrogel. The observed morphological images clearly show the homogeneous dispersion of carbon nanotubes (CNTs) and graphene oxide (GO) in the PNIPAM matrix. The complex formation of CNTs and GO with NIPAM is evidenced from the structural characterizations. The effectual MFC performances are influenced by combining the materials of interest (GO and CNTs) and are attributed to the high surface area, number of active sites, and improved electron-transfer processes. The obtained higher MFC efficiencies associated with an excellent durability of the prepared hydrogels open up new possibilities for MFC anode applications.

Network formation in graphene oxide composites with surface grafted PNIPAM chains in aqueous solution characterized by rheological experiments.

Poly N-isopropyl acrylamide (PNI) radically polymerized in aqueous solution in the presence of graphene oxide (GO) can significantly change the properties of the resulting solution from a regular polymer solution to a soft solid with a GO content of only 0.176 wt% (3 wt% with respect to PNI). However, these properties require the presence of both grafting and supramolecular interactions between polymer chains and hydrophilic groups on GO (-OH, -COOH), proven by Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), X-ray diffraction and spectroscopy (XRD) and Raman spectra. While very low GO-contents (below 0.05 wt%) only lead to a labile structure, which can be disassembled by shear, higher contents yield composites with solid-like characteristics. This is clearly evident from the rheological behaviour, which changes significantly at a GO content around 0.15 wt%. Intensive shearing destroys the weak network, which cannot reform quickly at lower GO-concentrations, while at intermediate concentrations, restructuring is fast. GO-contents of 0.176 wt% lead to a material behaviour, which almost perfectly recovers from small deformations (creep and creep recovery compliance almost match) but larger deformations lead to permanent damage to the sample.

Synthesizing pectin-crosslinked gum ghatti hydrogel for efficient adsorptive removal of malachite green.

Pectin-crosslinked gum ghatti hydrogel (PGH) has been synthesized utilizing pectin and gum ghatti through an uncomplicated and inexpensive copolymerization method. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM-elemental mapping), Brunauer-Emmett-Teller (BET), and X-ray photoelectron spectroscopy (XPS) characterization techniques have been employed to determine various structural, chemical and compositional characteristics of fabricated PGH. Three different weight ratios (1:1, 2:1, or 1:2 for pectin and gum ghatti, respectively) were employed to synthesize three distinct types of PGH. Swelling studies has been done to determine the best ratios for PGH fabrication. PGH has been assessed as an adsorbent for the removal of malachite green dye from aqueous solutions. The effects of PGH dosage (100-400 mg/L), dye concentration (10-160 mg/L), pH (2-9 pH), adsorption time (0-480 min), and temperature (25-55 °C) has been examined through batch solutions. According to Langmuir isotherm analysis, the maximum adsorption capacity is 658.1 mg/g. By using pseudo-second-order kinetics and the Freundlich adsorption isotherm, the adsorption process could be well explained. After five consecutive cycles, PGH had an adsorption percentage of 86.917 % for the malachite green dye. It is safe for the environment and may be used to remove malachite green (MG) dye from aqueous solutions.

Rapid self-assembly of self-healable and transferable liquid metal epidermis.

Healable electronic skins, an essential component for future soft robotics, implantable bioelectronics, and smart wearable systems, necessitate self-healable and pliable materials that exhibit functionality at intricate interfaces. Although a plethora of self-healable materials have been developed, the fabrication of highly conformal biocompatible functional materials on complex biological surfaces remains a formidable challenge. Inspired by regenerative properties of skin, we present the self-assembled transfer-printable liquid metal epidermis (SALME), which possesses autonomous self-healing capabilities at the oil-water interface. SALME comprises a layer of surfactant-grafted liquid metal nanodroplets that spontaneously assemble at the oil-water interface within a few seconds. This unique self-assembly property facilitates rapid restoration (<10 s) of SALME following mechanical damage. In addition to its self-healing ability, SALME exhibits excellent shear resistance and can be seamlessly transferred to arbitrary hydrophilic/hydrophobic curved surfaces. The transferred SALME effectively preserves submicron-scale surface textures on biological substrates, thus displaying tremendous potential for future epidermal bioelectronics.