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Osteoporosis is one of the most prevalent age-related diseases worldwide and is characterized by a systemic deterioration of bone strength (bone mineral density and bone quality) with a resulting increase in fragility fractures. Due to the complex osteoporotic pathological environment, it is a huge challenge to induce bone regeneration under osteoporosis conditions. In this study, we successfully nanoengineer a bioinspired mineralized hydrogel from the supramolecular assembly of nano-hydroxyapatite, sodium carbonate, and polyacrylic acid, termed as CHAp-PAA. The resultant nanocomposite hydrogels can maintain their initial morphology and mechanical properties under physiological conditions, while exhibiting good primary stability, biocompatibility, bioactivity, and osteoconductivity. We demonstrate that this optimized hydrogel scaffold has shown superior performance for bone marrow stem cells (BMSCs) proliferation, differentiation, and extracellular matrix production in vitro. Remarkably, the mineralized CHAp-PAA hydrogels could be used as scaffolds for the critical-sized bone defect (6.0 mm diameter and 10.0 mm depth) in the osteoporotic rabbit model. Without the delivery of additional therapeutic agents or stem cells, these CHAp-PAA hydrogel scaffolds can improve bone ingrowth and accelerate new bone formation even in complex osteoporotic pathological environments. Therefore, this work presents a type of bioinspired multifunctional mineral hydrogel that offers an alternative strategy to manage osteoporosis. Statement of Significance • We successfully nanoengineer a bioinspired mineralized hydrogel from supramolecular assembly of nano-hydroxyapatite, sodium carbonate, and polyacrylic acid, termed as CHAp-PAA. The resultant nanocomposite hydrogels can maintain their initial morphology and mechanical properties under physiological conditions, while exhibiting good primary stability, biocompatibility, bioactivity, and osteoconductivity. • We demonstrate that this optimized hydrogel scaffold has shown superior performance for bone marrow stem cells (BMSCs) proliferation, differentiation, and extracellular matrix production in vitro. • Remarkably, the mineralized CHAp-PAA hydrogels could be used as scaffold for the critical-sized bone defect (6.0 mm diameter and 10.0 mm depth) in osteoporotic rabbit model. Without delivery of additional therapeutic agents or stem cells, these CHAp-PAA hydrogel scaffolds can improve bone ingrowth and accelerate new bone formation even in complex osteoporotic pathological environment.

Luminescent films have received great interest for chemo-/bio-sensing applications owing to their distinct advantages over solution-based probes, including their good stability; ease of storage, transport, and recycling; tunable shape and size; and non-invasive nature. In this study, mechanically stable polyurethane/carbon dot (PU/CDs) composite films with dual-emission for ratiometric temperature sensing were prepared. The films exhibited good light transmissivity, flexibility, and ductility. The obtained PU/CDs hybrid films with dual emission exhibited temperature response and reversible properties from 10 °C to 90 °C. At the appropriate reactive ratio of CDs to PU, the fluorescent color of the films shifted over a relatively large range from blue to green to yellow over a large temperature range. These findings indicate that the stretchable hybrid PU/CDs composite films could potentially be applied for colorimetric detection over a large temperature range (10 °C–90 °C). These materials thus have high application value for macroscopic dual-light temperature detection as well as further development of polymer composite modification.

All-inorganic cesium lead halide perovskites have received much attention, but the study of the formation pathway is relatively little. We report here a new one-step approach for the synthesis of C...

The dispersion of carbon nanotubes (CNTs) in water under thermal excitation has been investigated by molecular dynamics (MD) simulations. The pressure and temperature distribution of the combination of CNTs and water indicate that water molecules have increased kinetic energy under thermal excitation. The absolute value of the potential of mean force (PMF) and the mean square displacement (MSD) of CNTs significantly increase with the increase of temperature in the thermal excitation region. It can be concluded that CNTs have a higher tendency of separation at higher temperatures with the assistant of water.

Diverse rubber composites filled with two types of thermal conductive fillers of carbon nanotubes (CNTs) and aluminum nitride (AlN) have been experimentally investigated. AlN in the composite serves as a bridge to join CNTs and to form a heat transfer network in the composites, while CNTs in the composite are either randomly or orientationally aligned. Both types of fillers have been found to improve the viscosity and thermal conductivity of the composite to some extent, while viscosity and thermal conductivity can both reach a maximum value when CNTs and AlN have the same content. Thermal conductivity of the composite with randomly aligned CNTs is superior to that with orientationally aligned CNTs. The highest thermal conductivity of 0.502 W/(m K) is obtained when the two kinds of fillers have a volume ratio of 1/1. AlN can reduce the tensile and tear strength of the composite while CNTs improve them. Tensile properties of the composite filled with oriented CNTs are better than that with random CNTs. The electrical conductivity of the composite can be improved with the increase in the loading of CNTs.

A method is described here for the quickly (

Doubly charged pH-responsive core/shell hydrogel nanoparticles with green fluorescence were prepared and were shown to be viable bioprobes for active targeting tumor tissue and imaging of cancer cells. Via emulsionfree copolymerization hydrogel nanoparticles as VANPs were prepared, the core of which was polystyrene (Ps) and the shell was comprised of strongly positive electrolyte (ar-vinylbenzyl)trimethylammonium (VBTAC) with weak negative electrolyte acrylic acid (AA). Through conventional amidation, the shell was conjugated with cell-specific folic acid (FA), denoted as VANPs-FA. Then, negatively charged sulfonated 9,10-distyrylanthracene derivatives (SDSA) based on aggregation induced emission (AIE), was binding tightly to positively charged VBTAC of VANPs-FA shell. The prepared double charged fluorescent core/shell hydrogel nanoparticles abbreviated as VANPs-FS, showed excitation/emission wavelengths at ~420/528 nm. Dynamic light scattering (DLS) measurements were performed to determine the size and surficial zeta potential of VANPs-FS. Under proper ratio of VBTAC to AA, the VANPs-FS was stable (~ 64.63 nm, -20.2 mV) at high pH (7), started to aggregate (~ 683.0 nm, -3.2 mV) at pH around 6, and can redispers at low pH (5). The MTT analysis proved that VANPs-FS had good biocompatibility and low cytotoxicity. The targeting effectiveness of VANPs-FS was confirmed by confocal laser scanning microscopy (CLSM). Graphical abstract Detailed synthetic route of VANPs-FS (top) and schematic cancer tumor-target aggregation of pH-sensitive VANPs-FS with enhanced retention and rapid cancer cell imaging (bottom).

A three-dimensional computational model was developed to study the thermal behaviour of multi-walled carbon nanotube (MWNT)-polymer composites. A lattice Boltzmann algorithm has been introduced to ...

Phenacyl quinolinium bromide (PaQBr), an old-fashioned corrosion inhibitor in strong acid medium, was reinvestigated and a new indolizine derivative (DiPaQBr) was synthesized from PaQBr. DiPaQBr is classified as an indolizine quaternary ammonium salt. Based on high resolution mass spectrometry (HRMS) and nuclear magnetic resonance spectroscopy (NMR), the formula and chemical structure of DiPaQBr was accurately confirmed and characterized. The formation mechanism of DiPaQBr from the condensation of two molecules of PaQBr through 1,3-dipolar cycloaddition was proposed. The corrosion inhibition of PaQBr and DiPaQBr on N80 steel in 15% HCl was investigated by weight loss measurements, potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). Polarization results indicate that the two compounds examined are mixed-type inhibitors. The adsorption of the studied inhibitors obeyed the Langmuir adsorption isotherm. The obtained results from gravimetric research as well as electrochemical studies indicated that compared with the inhibitive PaQBr, its indolizine derivative DiPaQBr exhibited a better corrosion prevention performance at a much lower concentration. The achieved results indicate that the derivative (the indolizine quaternary ammonium salt) of heterocyclic quaternary ammonium salts could inhibit the steel more effectively in acid medium.

Gold nanoclusters have attracted widespread attention because of their unique optical and physical properties. However, traditional synthesis methods are complicated and require additional reducing agents, while the yield is often very low. Such resource and time-consuming synthesis processes limit their further application. Herein, a rapid sonochemical route is used to synthesize fluorescent Au nanoclusters in large quantities using glutathione (GSH) both as a capping and reducing agent. These Au nanoclusters are synthesized quickly (∼40 min) due to the presence of ultrasonic waves, and show orange red photoluminescence (Em = 598 nm), small size (∼2 nm) and good dispersion in aqueous solution. Moreover, GSH, as a protecting agent on the surface of resultant Au nanoclusters, has many functional groups including carboxyl and amino groups because of which the nanoclusters show high photo-, storage-, metal- and pH-stability. A stable Au nanoclusters-based nano-sensor is designed for highly sensitive and selective label-free detection of Cu2+ with a low limit of detection of 7 ppb (based on S/N = 3). The fluorescent probe can be used in versatile nanothermometry devices, because their photoluminescence intensity correlates strongly with temperature and varies considerably over a wide temperature range (20–80 °C). Therefore, the novel fluorescent sensing probe has great application prospects in Cu2+ detection and temperature sensing.

Intelligent soft materials have been intensively investigated during the past few decades. Herein, nanocomposite hydrogels are constructed for detection of multiple external stimuli by the naked-eye. The nanocomposite hydrogels were prepared by reacting oxidized sodium hyaluronate with carbon dots. As a result, the hydrogels are capable of self-healing and strong fluorescence, as well as having multiple stimuli-responsive properties. The gelation mechanism of the dynamic crosslinked reaction in these hydrogels was demonstrated. Interestingly, the hydrogels exhibit sharp phase transitions and fluorescence changes in response to multiple external stimuli, including various chemical redox reactions, enzymes, biomolecules, cations, and pH values. This stimuli-responsive property has been successfully exploited to design programmable logic-gate responses. This investigation opens the door to developing logic-gate responsive hydrogels, which may become a powerful method to visually detect multiple environmental changes through the observation of the phase transition and fluorescence change.

Multiple functions incorporated in one single component material offer important applications in biosystems. Here we prepared a divalent state of rare earth EuS nanocrystals (NCs), which provides luminescent and magnetic properties, using both 1-Dodecanethiol (DT) and oleylamine (OLA) as reducing agents. The resultant EuS NCs exhibit controllable shapes, uniform size, and bright luminescence with a quantum yield as high as 3.5%. OLA as a surface ligand plays an important role in tunable morphologies, such as nanowires, nanorods, nanospheres et al. Another attractive nature of the EuS NCs is their paramagnetism at room temperature. In order to expand the biological applications, the resultant EuS NCs were modified with amphiphilic block copolymer F127 and transferred from oil to water phase. The excellent biocompatibility of EuS NCs is demonstrated as well as preservation of their luminescence and paramagnetic properties. The EuS NCs offer multifunction and great advantages of bright luminescence, paramagnetic, controllable morphologies, and good biocompatibility promising applications in the field of simultaneous magnetic resonance and fluorescence bioimaging.

We report, for the first time, the synthesis of CdS magic-size clusters (MSCs) which exhibit a single sharp absorption peaking at ∼ 361 nm, along with sharp band edge photoemission at ∼ 377 nm and broad trap emission peaking at ∼ 490 nm. These MSCs are produced in a single-ensemble form without the contamination of conventional quantum dots (QDs) and/or other-bandgap clusters. They are denoted as MSC-361. We present the details of several controlled syntheses done in oleylamine (OLA), using Cd(NO3)2 or Cd(OAc)2 as a Cd source and thioacetamide (TAA) or elementary sulfur (S) as a S source. A high synthetic reproducibility of the reaction of Cd(NO3)2 and TAA to single-ensemble MSC-361 is achieved, the product of which is not contaminated by other bandgap clusters and/or QDs. In some cases, the reaction product exhibits an additional absorption peak at ∼ 322 nm. We demonstrate that the two peaks, at 361 and 322 nm, do not evolve synchronously. Therefore, the 322 nm peak is not a higher order electronic transition of MSC-361, but due to the presence of another ensemble, namely MSC-322. The present study suggests that there is an outstanding need for the development of a physical model to narrow the knowledge gap regarding the electronic structure in these colloidal semiconductor CdS MSCs.

Alloy semiconductor magic-size clusters (MSCs) have received scant attention and little is known about their formation pathway. Here, we report the synthesis of alloy CdTeSe MSC-399 (exhibiting sharp absorption peaking at 399 nm) at room temperature, together with an explanation of its formation pathway. The evolution of MSC-399 at room temperature is detected when two prenucleation-stage samples of binary CdTe and CdSe are mixed, which are transparent in optical absorption. For a reaction consisting of Cd, Te, and Se precursors, no MSC-399 is observed. Synchrotron-based in-situ small angle X-ray scattering (SAXS) suggests that the sizes of the two samples and their mixture are similar. We argue that substitution reactions take place after the two binary samples are mixed, which result in the formation of MSC-399 from its precursor compound (PC-399). The present study provides a room-temperature avenue to engineering alloy MSCs and an in-depth understanding of their probable formation pathway., Alloy magic-size clusters (MSCs) are difficult to synthesize, in part because so little is known about how they form. Here, the authors produce single-ensemble alloy CdTeSe MSCs at room temperature by mixing prenucleation-stage solutions of CdTe and CdSe, uncovering a formation pathway that may extend to the synthesis of other alloy MSCs.

International audience; Possibility theory is applied to introduce and reason about the fundamental notion of a key for uncertain data. Uncertainty is modeled qualitatively by assigning to tuples of data a degree of possibility with which they occur in a relation, and assigning to keys a degree of certainty which says to which tuples the key applies. The associated implication problem is characterized axiomatically and algorithmically. Using extremal combinatorics, we then characterize the families of non-redundant possibilistic keys that attain maximum cardinality. In addition, we show how to compute for any given set of possibilistic keys a possibilistic Armstrong relation, that is, a possibilistic relation that satisfies every key in the given set and violates every possibilistic key not implied by the given set. We also establish an algorithm for the discovery of all possibilistic keys that are satisfied by a given possibilistic relation. It is shown that the computational complexity of computing possibilistic Armstrong relations is precisely exponential in the input, and the decision variant of the discovery problem is NP-complete as well as W[2]-complete in the size of the possibilistic key. Further applications of possibilistic keys in constraint maintenance, data cleaning, and query processing are illustrated by examples. The computation of possibilistic Armstrong relations and discovery of possibilistic keys from possibilistic relations have been implemented as prototypes. Extensive experiments with these prototypes provide insight into the size of possibilistic Armstrong relations and the time to compute them, as well as the time it takes to compute a cover of the possibilistic keys that hold on a possibilistic relation, and the time it takes to remove any redundant possibilistic keys from this cover.

The profiling of disease-related biomarkers is an essential procedure for the accurate diagnosis and intervention of metabolic disorders. Therefore, the development of ultrasensitive and highly selective fluorogenic biosensors for diverse biomarkers is extremely desirable. There is still a considerable challenge to prepare nanocluster-based fluorescence turn-on probes capable of recognizing multiple biomolecules. We herein provide a novel nanocluster-based chemical information processing system (CIPS) for the programmable detection of various metabolites and enzymes. This CIPS consists of biocatalytic reactions between substrates and their respective oxidases to generate H2O2, which was then employed to synthesize bright fluorescent silver nanoclusters (Ag NCs). Utilizing this system, we are able to accurately probe a series of substrates/corresponding oxidases with high sensitivity and specificity, including glucose/glucose oxidase, uric acid/uric acid oxidase, sarcosine/sarcosine oxidase, choline/cholin...

As a kind of temperature-responsive hydrogel, polystyrene-co-poly(N-isopropylacrylamide)/poly(N-isopropylacrylamide) (PS-co-PNIPAM/PNIPAM) core-shell nanoparticles prepared by two-step copolymerization are widely studied and used because of their specific structures and properties. Unlike most reports about the steady stability of PS-co-PNIPAM/PNIPAM core-shell nanoparticle hydrogel emulsion, in this work, the PS-co-PNIPAM/PNIPAM core-shell nanoparticle hydrogel emulsion (symbolized as PS/PNIPAM hydrogel emulsion), which is prepared after the second step of synthesis and without washing out a large number of PNIPAM polymer segments, shows a reversible temperature-dependent sol-gel transition characteristic during the temperature range of 34-80 °C. The PS/PNIPAM hydrogel emulsion is a normal solution at room temperature, and it changes from a sol to a gel statue when the temperature approaches up to low critical solution temperature (LCST). As the temperature continues to increase, the gel (core-shell nanoparticles as the crosslinkers and the linear PNIPAM chain as the 3D gel network) of the PS/PNIPAM hydrogel emulsion gradually shrinks and drains linearly. Compared with most crosslinked hydrogels, the hydrogel here can be arbitrarily changed in shape according to use needs, which is convenient for use, transportation, and storage. Here a new route is provided for the preparation of a PS/PNIPAM core-shell hydrogel nanoparticle system, as well as a new supramolecular crosslinking sol-gel system for application in biomedical materials, sensors, biological separation, drug release, macromolecular adsorption, and purification.

The authors describe strongly red-emitting carbon dots (CDs) which were obtained via microwave synthesis using phenylenediamine as the carbon source. The structural and optical properties of the resultant CDs are studied in some detail. The CDs possess (a) longwave emission (peaking at 620 nm under 470 nm excitation), (b) a quantum yield of ~15%, (c) a size of typically 3.8 nm; and (d) good photostability. The CDs have a pH-dependet response that covers the pH 5 to 10 range, and their fluorescence is quenched by ferric ions. The CDs can detect ferric ions in aqueous samples in the 0 to 30 μM concentration range with a lower detection limit of 15 nM. The CDs were also used to image pH values and ferric ions in E. coli bacteria. Graphical abstract The red-emitting carbon dots with high stability are synthesized which show dual response to pH-values and ferric ions in aqueous solution and biological media simultaneously.

A one-step facile method of synthesizing fluorescent carbon dots (CDs) has been demonstrated, whereby fluorescent CDs are produced through hydrothermal treatment of glucose in the presence of H3BO3 with a fluorescence quantum yield of 14.5%. It is found that spherical CDs have an average size of 3.7[Formula: see text]nm as well as good monodispersion in aqueous solution. The added Cr (VI) selectively leads to the inner filter effect (IFE)-based fluorescence quenching of the CDs. Such fluorescence responses can be used for well quantifying Cr (VI) in the range of 0.05–200[Formula: see text][Formula: see text]M. Significantly, the CDs possess negligible cytotoxicity, excellent biocompatibility and high selectivity. All these features are favorable for label-free monitoring of Cr (VI) in complex biological samples. It was then successfully applied for the fluorescence imaging of intracellular Cr (VI). As an efficient chemosensor, the CDs hold great promise in broadening their applications in biological systems.