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A block-copolymer (PS-b-PAA) micelle was demonstrated to be a suitable model particle to predict the migration of pseudo-colloids of natural organic matter (NOM) and uranyl carbonate (UC) in aqueous solutions.

The interactions between natural colloidal organic matter and actinides in solutions are complex and not fully understood. In this work, a crew-cut polystyrene-b-poly(acry1ic acid) (PS-b-PAA) micelle is proposed as a model particle for humic acid (HA) colloid with the aim to better understand the sequestration, aggregation, and mobility of HA colloids in the presence of uranyl ions. The effects of uranyl ions on the structure of PS29k-b-PAA5k micelles in aqueous solution were mainly investigated by synchrotron small-angle X-ray scattering. A core-shell model, accounting for the thickness and contrast changes of the PAA corona induced by the adsorption of uranyl, was employed to analyze the scattering data. A combination of transmission electron microscopy, dynamic light scattering, and zetametry showed a strong affinity of uranyl ions to PAA segments in water at pH 4-5 that resulted in the shrinkage and improved contrast of the PAA corona, as well as colloidal destabilization at a high uranyl concentration.

Large scale extraction of uranium from oceans for energetic or decontamination purposes is becoming credible as more and more efficient adsorbing materials are developed. Although these sorbents are intended to be massively spread in ecosystems, there is still a lack of eco-friendly solutions. Calcium carbonate is a biocompatible material naturally present in marine environments. In this study, pure CaCO3 particles and their hybrid versions coated with poly(acrylic acid) (CaCO3-PAA) and poly(ethyleneimine) (CaCO3-PEI) are presented as environment-friendly alternatives. Uranium extraction capabilities of CaCO3, CaCO3-PAA and CaCO3-PEI were assessed in artificial seawater containing 2.8 to 10 000 ppb of uranium in order to simulate both natural and contaminated conditions. Stability of uranium/particle complexes was also investigated. CaCO3 and CaCO3-PEI are suitable for uranium harvesting at 2.8 ppb (removal rate > 62%) while all types of particles perform excellently under highly contaminated conditions with an advantage for CaCO3-PEI which shows the best selectivity toward uranium. Polyelectrolyte coatings were found to stabilize uranium/particle complexes whereas taken up uranium was almost completely self-released from bare CaCO3 over 6 days. Such behavior, in addition to CaCO3 biocompatibility, efficiency and cost-effectiveness, opens the way for simplification of extraction processes as no desorption step is required.

Stable mineral colloids play a role in the mobilization of actinide contaminants in the environment. In this paper we present a method to isolate and identify colloids released from high surface area sorbents associated with a proposed clay mineral barrier in a nuclear waste repository. The mineral colloids, which have a strong tendency to remain dispersed in solution, were separated from Al13- or (Ce Al)-pillared clay sediment, adsorbed on glass together with hydrolyzed vanadium(IV) species and studied by a variety of techniques including grazing-incidence X-ray scattering (GIXS), small-angle X-ray scattering (SAXS), Fourier transform-infrared spectroscopy (FT-IR) and atomic force microscopy (AFM). We show that the clay platelets are dimensionally orientated in the continuous, transparent 100 nm thick film until the onset of vanadium oxides above 350 °C. Organic matter and the secondary mineral quartz limit the swelling capacity of the platelets, an indication that the stable colloids originate from a part of the native clay that could not be intercalated by aluminum cations. X-ray scattering from oriented clay films intercalated by aluminum- and mixed cerium/aluminum oxo-hydroxy cations are also investigated by the GIXS technique.

Hypothesis Nanoparticles functionalized with ligands which can on-demand and remotely be detached have recently attracted interest as stimuli-responsive materials. Research is now focused on multi-responsive systems, with applications in environmental science and biomedicine. The possibility to covalently couple two different ligands on a single nanoparticles, and to release them independently is investigated. This concept of nanoparticles functionalized with dual on-demand cleavable ligands is exploited in ground water decontamination and radionuclides separation. Efficient separation of contaminants in a single step is expected, simplifying partitioning process and decreasing generation of secondary waste by nuclear industry. Experiments Sub−10 nm Janus superparamagnetic nanoparticles are functionalized by click-chemistry (thiol and Diels-Alder) with two different Actinide-specific chelators. The reversible covalent bonds allow to detach chelators independently by either pH- or thermo-stimulation. The nanoparticles decorated with diethylenetriamine-pentaacetic acid (DTPA) and [(2-furan-2-yl-2-hydroxy-ethylcarbamoyl)-methoxy]-acetic acid (FHECMAA) are incubated with UO22+ and La3+ (as substitute for Pu3+) at pH = 3 and 7 before chelator-metal complexes are released. Metal contents are measured to determine separation efficiency. Findings Chelators can be detached from Janus nanoparticles with perfect selectivity. The nanoparticles are highly efficient for extraction of metals in acidic medium and show good ability for separation of U and La at neutral pH.

Seneca Valley virus (SVV) is a non-encapsulated single-stranded positive-strand RNA virus whose transmission routes have not yet been fully elucidated. Exosomes have been implicated in the intercellular transport of a variety of materials, such as proteins, RNA, and liposomes. However, whether exosomes can mediate SVV intercellular transmission remains unknown. In this study, we extracted exosomes from SVV-infected IBRS-2 cells to investigate intercellular transmission. Our results suggest that the intercellular transmission of SVV is mediated by exosomes. The results of co-localization and RT-qPCR studies showed that exosomes harbor SVV and enable the virus to proliferate in both susceptible and non-susceptible cells. Furthermore, the replication of SVV was inhibited when IBRS-2 cells were treated with interfering RNA Rab27a and exosome inhibitor GW4869. Finally, neutralization experiments were performed to further verify whether the virus was encapsulated by the exosomes that mediated transmission between cells. It was found that exosome-mediated intercellular transmission was not blocked by SVV-specific neutralizing antibodies. This study reveals a new transmission route of SVV and provides clear evidence regarding the pathogenesis of SVV, information which can also be useful for identifying therapeutic interventions.

During the past decade, deep eutectic solvents (DESs) have shown promising application in the self-assembly of surfactants. Various aggregates such as micelles, vesicles, lyotropic liquid crystals, microemulsions and gels have been reported. In this research, the phase behaviours of imidazolium surface active ionic liquids (SAILs) CnmimBr (n = 12, 14, 16) were investigated in ChG. With the help of small angle X-ray scattering (SAXS), the types and structure parameters of aggregates were determined. The molecular packing of SAILs was influenced by the solvophobic chain length, surfactant concentration, temperature and solvent, accounting for their different aggregation behaviours. This study would give a good description of the molecular packing of surfactants in DESs.

Colloidal particles based on supramolecular polymers are emerging as promising functional materials because of their intrinsic dynamic features and the possibility of stimuli responsivity. In this work, ≈200 nm self-assembled redox-responsive colloidal particles made of 1D-coordination polymers were readily prepared. In these metallopolymers, organic entities made of bis(viologen) groups covalently associated with terpyridine units are spontaneously bridged by Zn2+ cations through the formation of coordination bonds. The properties of these particles were analyzed and their redox activities investigated. Upon reduction of the viologen units, the formation of π-dimers between the reduced viologen moieties was demonstrated by spectroscopic experiments. It was shown that intermolecular π-dimers (i.e., between different polymer chains) that do not exist in homogeneous polymer solutions were, nevertheless, formed in the particle's structure because of the effects of confinement. The presence of these π-dimers allows stabilization of the charge in the colloids.

The interactions between natural colloidal organic matter and actinides in solutions are complex and not fully understood. In this work, a crew-cut polystyrene

Structure is a crucial factor to decide the selectivity and sensitivity of chemosensors. In this work, a diacylhydrazone 2a and its congeneric derivatives 2b-2d were synthesized and their applications for Al3+ detection were investigated. Except 2d, all the other compounds exhibit notable turn-on fluorescence toward Al3+ over 15 other metal ions and the sensitivities of 2b and 2c are even higher after modification, illustrating ortho-OH indispensability in their structures for sensing. Reversibility investigation shows that the sensors all have regeneration ability. Meanwhile, the sensor-Al3+ systems show selective fluorescence turn-off for Cu2+, providing a potential platform for tandem recognition of Al3+ and Cu2+. 2a as a standard, shows a 1:2 molar ratio to Al3+ confirmed by Job’s plot, 1H NMR spectra and mass spectra, and its detection limit for Al3+ is 7.63 nM in ethanol. It has relevant sensitivity over pH 3-9, with the highest sensitivity at around pH 4. Apart from Al3+ detection, anion selectivity was also explored and it shows that 2a, 2b and 2c all have selectivity toward CN− evidenced by UV-vis spectra.

The fluorapatite-type Ca8Sm1Na1(PO4)6F2 ceramic was successfully fabricated by hot uniaxial pressing (HUP) sintering process. The effects of sintering temperature and holding time on the relative density and Vickers hardness of the ceramic were investigated. The surface microstructure, weight loss rate and surface composition of Ca8Sm1Na1(PO4)6F2 ceramic before and after the leaching experiment were examined. The influences of leaching temperature and pH value on the chemical durability of the ceramic were also studied. The results showed that the ceramic sintered by HUP at 1100 °C for 2 h obtained the highest relative density (99.46%) and maximum Vickers hardness (3.704 GPa). The largest weight loss rate (0.578%) and the highest normalized elemental leaching rates of Sm, Ca, P, Na and F were obtained in the media (pH = 3) at 90 °C. The surface of ceramic in the media (pH = 3) appeared obvious corrosion with plenty of intergranular and intragranular pores. The small weight loss rates (0.003%–0.008%) and the low normalized elemental leaching rates of Ca (7.44 × 10−3 g m-2 d-1 - 8.22 × 10−4 g m-2 d-1) and Sm (9.11 × 10−6 g m-2 d-1 - 1.07 × 10−6 g m-2 d-1) were acquired in the media (pH = 7, 9 and 11), indicating that the Ca8Sm1Na1(PO4)6F2 ceramic possessed high chemical durability in the neutral and alkaline media at 90 °C.

Small-angle scattering was employed to characterize the gradual phase mixing and separation of Estane 5703p, a type of polyester polyurethane, as a function of temperature (20–110 °C) and time (minutes to 80 days). The polymer structure was modelled by polydisperse hard spheres, and microstructure evolution of the material was inferred from the development of the fitting parameters. At temperatures higher than 40 °C, the scattering data indicated the mixing of hard domains (MDI-BDO) with soft matrix (PBA). The hard domain distance showed a sharp increase at 50–60 °C. Between 60 and 90 °C, a newly-observed ordering signalled the formation of a distinct mesophase with a repeat distance of 5.15 nm. Upon heating, the morphology evolution in Estane follows: domain intermixing – mesophase formation – final melting. After cooling, the domain structure partly recovered, but did not reach the original state during storage at room temperature for 80 days.

We have fabricated highly ordered anodized aluminum oxide (AAO) membranes with different diameter through improved hard anodization (HA) at high temperature. This process can generate thick AAO membranes (30 μm) in a short anodizing time with high growth rate 20-60 μm h-1 which is much faster than that in traditional mild two-step anodization. We enlarged the AAO pore diameter by adjusting the voltage rise rate at the same time, which has a great influence on current density and temperature. The AAO pore diameter varies from 60-110 nm to 160-190 nm. The pore diameter (Dp) of the AAO prepared by this improved process is much larger than that prepared by HA (40-60 nm) when H2C2O4 as electrolyte. It can expand potential use of the AAO membranes such as for the template-based synthesis of nanowires or nanotubes with modulated diameters and also for practical separation technology. We also has used the AAO with different diameters prepared by this improved HA to fabricate Co nanowires and γ-Fe2O3 superparamagnetic nanorods.

Removal of uranium(VI) from uranium(VI) containing waste water is urgently needed with the global nuclear energy exploitation. The present work have successfully completed removal of uranium(VI) by natural fluorapatite. The natural fluorapatite before and after adsorption of uranium(VI) was characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). The experimental results are as follows: (1) At 308 K and pH3, solid-liquid ratio is 0.12 g/L, equilibrium time is 180 min and initial uranyl ion concentration is 100 mg/L, the adsorption capacity of uranium(VI) by natural fluorapatite reaches 620.08 mg/g and the concentration of uranyl ion after adsorption is 25.59 mg/L; (2) The adsorption process of uranium(VI) by natural fluorapatite is in accordance with the pseudo-second-order kinetics and Langmuir isotherm adsorption model; (3) The adsorption of uranium(VI) by natural fluorapatite is a spontaneous and endothermic reaction. The results show that the removal mechanism of uranium(VI) by natural fluorapatite is surface mineralization. After adsorption of uranium(VI) is conducted, two new phases of meta-autunite (Ca(UO2)2(PO4)2.2H2O, Ca(UO2)2(PO4)2.6H2O) are generated on the surface of natural fluorapatite. The meta-autunite can maintain high stability in pH ≥ 3 aqueous solution. Consequently, natural fluorapatite can be used as the promising mineralizer for the purification and solidification treatment of uranium(VI) containing waste water.

There is a demand to develop highly efficient and selective materials for removal of uranyl species from aqueous solutions. Herein, titanium carbide (Ti3C2TX-Li) agglomerates composed of plate fragments were synthesized by etching MAX (Ti3AlC2) powders in HF/LiCl solution. Compared to reference samples, hydrated Ti3C2TX-Li showed the best affinity for U(VI) (qm = 1.12 mmol/g) and a sorption capacity>90% (0.04–0.2 mM initial U(VI)). The efficient sorption capacity of hydrated Ti3C2TX-Li was attributed to larger interlayer spacing and smaller lateral dimensions of the plate fragments (0.1–3 μm), which facilitated the U(VI) species to reach deeper sorption sites in the interlayer compared with the accordion-like Ti3C2TX. Uranium(VI) exhibited excellent selective sorption to hydrated Ti3C2TX-Li in the presence of Sm3+, Nd3+, Co2+, Cd2+, Zn2+, and Cu2+ (nitrates), due to the surface-mediated reduction of U(VI) to U(IV) and the oxidation of the Ti component of MXene.

In recent years, aggregates formed in deep eutectic solvents (DESs), especially micelles, have attracted much attention. In this study, the phase behaviours of a cationic surfactant, cetylpyridinium bromide (CPBr), in two DESs, choline chloride + glycerol (ChG) and choline chloride + ethylene glycol (ChEG), were investigated in wide concentration and temperature ranges. With the help of small angle X-ray scattering, polarized optical microscopy and rheological measurements, the structures and properties of various aggregates were characterized. The micelles, hexagonal phase, bicontinuous cubic phase and lamellar phase were observed with the increase of CPBr concentration. Such rich phase behaviours were due to the large cohesive energy densities of DESs. Comparative studies in water and ethylammonium nitrate were carried out to explore how well DESs acted as self-assembly media.

Colloidal particles based on self-assembled Cu2+ coordination polymers were fabricated following a one-step process. These particles were shown to be stimuli-responsive. In particular they can be readily disassembled in acidic conditions. This effect originates from a pH-induced fragmentation of the polymer chains into dinuclear Cu2+ complexes.

Core-shell polymer coated superparamagnetic nanoparticles are critical tools in bio-nanotechnology, in which the soft and thin polymeric coatings play a key role in their stabilization, surface functionality and biocompatibility. Standard characterization tools, such as Transmission Electron Microscopy are indispensable for the morphological characterization of the metal-containing core but they cannot clearly discriminate between core and shell components. Dynamic Light Scattering can only overestimate the shell thickness by measuring the particle hydrodynamic diameter. Here, we describe Small-Angle X-ray Scattering and Small-Angle Neutron Scattering as tools to study poly (acrylic) acid coated gamma iron oxide superparamagnetic nanoparticles dispersed in aqueous medium. Our results show that Small-Angle Scattering techniques offers in situ and sensitive measurements of the “stealth” polymer coatings which cannot be accurately detected by other techniques. The Small Angle Scattering approach presented in this work is applicable for analysis of core-shell organic/inorganic hybrid nanoparticles systems for a broad range of applications.

In the absence of external assistance, autogenous healing of bone fracture is difficult due to impaired regeneration ability under osteoporosis pathological conditions. In this study, a reduced graphene oxide/zinc silicate/calcium silicate (RGO/ZS/CS) conductive biocomposite with an optimal surface electroconductivity of 5625 S/m was prepared by a two-step spin-coating method. The presence of lamellar apatite nanocrystals on the surfaces of the biocomposite suggests that it has good in vitro biomineralization ability. The silicon and zinc released from the biocomposite induced a significant increase in the osteogenesis of mouse bone mesenchymal stem cells (mBMSCs). Furthermore, alkaline phosphatase activities were further promoted when 3 μA direct current was applied to stimulate the mBMSCs that were cultured on the RGO/ZS/CS surface. However, electrical stimulation failed to further upregulate the osteogenesis-related gene expression. Moreover, RGO/ZS/CS extracts were found to suppress the receptor activator of nuclear factor-κB ligand-induced osteoclastic differentiation of mouse leukemic monocyte macrophages (RAW264.7 cells). Although the zinc ions in the RGO/ZS/CS extracts showed an inhibitory role in human umbilical vein endothelial cell (HUVEC) proliferation, dilutions of the RGO/ZS/CS extracts (1/16, 1/32, and 1/64) promoted HUVEC proliferation, and their angiogenesis-related gene expression was also upregulated. On the basis of the results of the in vitro angiogenesis model, more interconnected tubes formed when the above dilutions of RGO/ZS/CS extracts were added to ECMatrix. The new RGO/ZS/CS electroconductive biocomposite has potential to be used for stimulating osteoporotic bone regeneration.

To improve the visible light absorption and photocatalytic activity of titanium dioxide nanotube arrays (TONTAs), ZnFe2O4 (ZFO) nanocrystals were perfused into pristine TONTA pipelines using a novel bias voltage-assisted perfusion method. ZFO nanocrystals were well anchored on the inner walls of the pristine TONTAs when the ZFO suspensions (0.025 mg mL−1) were kept under a 60 V bias voltage for 1 h. After annealing at 750 °C for 2 h, the heterostructured ZFO/Fe2TiO5 (FTO)/TiO2 composite nanotube arrays were successfully obtained. Furthermore, Fe3+ was reduced to Fe2+ when solid solution reactions occurred at the interface of ZFO and the pristine TONTAs. Introducing ZFO significantly enhanced the visible light absorption of the ZFO/FTO/TONTAs relative to that of the annealed TONTAs. The coexistence of type I and staggered type II band alignment in the ZFO/FTO/TONTAs facilitated the separation of photogenerated electrons and holes, thereby improving the efficiency of the ZFO/FTO/TONTAs for photocatalytic degradation of methylene blue when irradiated with simulated sunlight.

Superparamagnetic and flexible Fe2O3 nanowire arrays were fabricated by the controlled electrostatic assembly of iron oxide nanoparticles and poly(dimethyldiallylammonium chloride) (PDADMAC) in an anodic aluminum oxide (AAO) template. The micrograph of iron oxide nanowire arrays was characterized by field emission scanning electron microscopy. The magnetic hysteresis loops obtained by a vibrating sample magnetometer confirm that the nanowire arrays have superparamagnetic properties. The filling ratio of iron oxide nanoparticles and polymers in the AAO template was affected by four factors, including the concentration of iron oxide nanoparticles, the pore diameter of the AAO template, the charge ratio of iron oxide nanoparticles and PDADMAC, and the molecular weight of polyacrylic acid. The effect of the AAO template on the diameter and length of the nanowire arrays was also analyzed. In addition, the nanowire arrays were shown to be flexible because of the presence of polymers. These nanowire arrays with superparamagnetic and flexural properties have potential applications in sensor probes.

An improved lossless group compression algorithm is proposed for decreasing the size of SEG-Y files to relieve the enormous burden associated with the transmission and storage of large amounts of seismic exploration data. Because each data point is represented by 4 bytes in SEG-Y files, the file is broken down into 4 subgroups, and the Gini coefficient is employed to analyze the distribution of the overall data and each of the 4 data subgroups within the range [0,255]. The results show that each subgroup comprises characteristic frequency distributions suited to distinct compression algorithms. Therefore, the data of each subgroup was compressed using its best suited algorithm. After comparing the compression ratios obtained for each data subgroup using different algorithms, the Lempel-Ziv-Markov chain algorithm (LZMA) was selected for the compression of the first two subgroups and the Deflate algorithm for the latter two subgroups. The compression ratios and decompression times obtained with the improved algorithm were compared with those obtained with commonly employed compression algorithms for SEG-Y files with different sizes. The experimental results show that the improved algorithm provides a compression ratio of 7580%, which is more effective than compression algorithms presently applied to SEG-Y files. In addition, the proposed algorithm is applied to the miniSEED format used in natural earthquake monitoring, and the results compared with those obtained using the Steim2 compression algorithm, the results again show that the proposed algorithm provides better data compression. An algorithm was proposed to compress losslessly the SEG-Y and miniSEED Files.It describes the distribution of SEG-Y and miniSEED files using Gini coefficient.Different data sub-groups should use different compression algorithms.The improved algorithm can achieve a better compression ratio of 7580%.It provides a better compression ratio than the Steim2 to miniSEED Files.

Electrostatic interaction of charged colloids and polyelectrolytes is a useful method to assemble matter into hybrid nanostructures with numerous examples in materials science as well as in biology. However, the colloidal electrostatic interaction is rapid and uncontrolled, the strong interaction usually leads to large and irregular aggregates. Therefore, control of the electrostatic interaction in order to resulting well-defined nanostructures remains a challenge. Here we report on a general and simple method to moderate the wild electrostatic interaction. Direct mixing of stock solutions containing anionic superparamagnetic nanoparticles and widespread cationic homopolyelectrolytes at an appropriate ionic strength generates aggregates with controlled shape and morphology. The simple and versatile methodology not only efficiently moderates electrostatic interactions but also enables the corresponding growth mechanism to be revealed by light scattering and electron microscopy as aggregation occurs at much slower timescales. The present results carry important implications for both practical applications and understanding on nanoscale electrostatic interaction between colloids.

International audience; Hypothesis: superparamagnetic iron oxide nanoparticles (SPIONs) are extensively used as building block of colloidal nanocomposites for biomedical applications. Strategies employed to embed them in a biodegradable and biocompatible polymer matrix often fail to achieve a high density of loading which would greatly benefit to applications such as imaging and hyperthermia. In this study, poly(acrylic acid) coated SPION (γ-Fe2O3-PAA) are self-assembled with hydrolysable poly(serine ester) by electrostatic complexation, leading to perfectly defined spherical particles with ultra-high density of magnetic material and an ability to auto-degrade into individual SPION and biocompatible byproducts.Experiments: self-assembly and auto-degradation of γ-Fe2O3-PAA/poly(serine ester) and γ-Fe2O3-PAA/poly(serine ester)-b-PEG colloidal particles are studied by light scattering and microscopy. Colloidal stability in bio-fluids, hyperthermia under alternating magnetic field, cellular uptake, cytotoxicity and degradation of γ-Fe2O3-PAA/poly(serine ester)-b-PEG in living cells are investigated.Findings: a remarkably slow electrostatic complexation leads to dense superparamagnetic γ-Fe2O3-PAA/poly(serine ester)-b-PEG polyion complexes (PICs) with controlled sizes (150 – 500 nm) and times of degradation in aqueous solvents (700 – 5000 h). The material shows good sustainability during hyperthermia, is well taken up by MC3T3 cells and non-cytotoxic. TEM images reveal a mechanism of degradation by “peeling” and fragmentation. In cells, PICs are reduced into individual SPIONs within 72 h.

Aim: The agglomeration of nanoparticles plays an important role in the preparation of nanostructured materials, which has implications in their practical applications such as plasma nanosensor and drug release. Materials & methods: Highly stable individual superparamagnetic γ-Fe2O3 nanoparticles with diameter of 5 nm were first synthesized in water. These particles were then assembled into spherical clusters with diameters of approximately 200 nm using a simple and versatile method. Results: The prepared γ-Fe2O3 nanoparticle-based clusters were then used for aminophylline drug loading and release properties investigation. The results show the high drug load rate, release speed and release rate. Conclusion: The present materials and method present great potential in drug-release application.

An improved threshold shift-invariant wavelet transform de-noising algorithm for high-resolution gamma-ray spectroscopy is proposed to optimize the threshold function of wavelet transforms and reduce signal resulting from pseudo-Gibbs artificial fluctuations. This algorithm was applied to a segmented gamma scanning system with large samples in which high continuum levels caused by Compton scattering are routinely encountered. De-noising data from the gamma ray spectrum measured by segmented gamma scanning system with improved, shift-invariant and traditional wavelet transform algorithms were all evaluated. The improved wavelet transform method generated significantly enhanced performance of the figure of merit, the root mean square error, the peak area, and the sample attenuation correction in the segmented gamma scanning system assays. We also found that the gamma energy spectrum can be viewed as a low frequency signal as well as high frequency noise superposition by the spectrum analysis. Moreover, a smoothed spectrum can be appropriate for straightforward automated quantitative analysis.

Spiropyran, as famous molecular sensor, can transform from its closed forms into the corresponding opened merocyanine through Cspiro-O bond cleavage when an analyte attacks the spirocarbon or oxygen atom in the spiropyran. Herein, a spiropyran-acylhydrazone dyad 4 is synthesized followed by spiropyran-like 5 and non-spiropyran diacylhydrazone 6 obtained simultaneously, and its reactivity to nucleophiles is investigated. Thus a third attacking position, located at the carbon atom opposite to the oxygen connected to Cspiro, is found, which involves Cspiro-O bond cleavage and recombination. Consequently, a nucleophilic addition mechanism in spiropyran is proposed. 4 and 5 both can discriminate Mg2+ from Ca2+ with different response time and sensitivity, while non-spiropyran 6 does not respond to the two metal ions. This work not only discovers an outstanding sensor for discriminating Mg2+ from Ca2+, but also provides new insight for transforming and modifying spiropyrans.

Recently, clays have been investigated for the long-term storage of spent nuclear fuel and nanominerals have been developed for the separation of radionuclides from subsurface water, but the detailed structure relating to pillaring of the sorbent is not always easily assessable by X-ray diffraction, for example, where the shift of the basal spacing to a higher value is not distinct. The purpose of this study was to gain an insight into the correlation between nanoscale structure and macroscopic sorption performance. The time dependence of 239‑plutonium sorption to Laponite, (Ce Al)-Laponite, and (Ce Al)-bentonite was studied. (Ce Al)-Laponite was characterized by TEM, XPS, XRD, N2 adsorption/desorption isotherms, and small-angle neutron scattering. Analysis of neutron scattering from dry powder and powder dispersed in water showed that (Ce Al)-Laponite has an open pore-fractal structure described by a fractal dimension Dp = 2.5, and a radius of gyration Rg = 6.5 nm. In a slightly alkaline pH condition, the strength of the sorption (Kd) of 239Pu by the different sorbents, from most to least, was (Ce Al)-bentonite (104) > (Ce Al)-Laponite (~104) > Laponite (103) > bentonite (103). The time it took for Pu sorption to reach equilibrium for (Ce Al)-Laponite was almost two times faster than that observed for the starting clays and the (Ce Al)-bentonite (8 days). A pseudo-second order rate expression was applied to the time-course data to describe the kinetic behavior. The enhanced rate of sorption was attributed to the connected pore system present in (Ce Al)-Laponite.

As Al3+ is detrimental both to human and other organisms, a simple sensor, acylhydrazone AhzF, is synthesized in one step and its structure is confirmed by single crystal X-ray diffraction. AhzF shows specific fluorescence turn-on response for Al3+ over other metal ions at UV 365 nm, observed by naked-eyes. Its detection limit can reach to 1.11 × 10−9 M in ethanol. Meanwhile, AhzF at low concentration can detect Al3+ with excellent interference resistance to typical disturbing metal ions including Cu2+ and Fe3+. For the first time, concentration influence of Fe3+ during AhzF detecting Al3+ has been explored and it has been found that the fluorescence of AhzF-Al3+ is partly quenched by Fe3+ while with no influence by Cu2+ at high concentration (above 10−6 M), indicating its good low concentration advantage during Al3+ detection. The binding mode exhibits a 1:1 M ratio between AhzF and Al3+, which are confirmed by titration test, Job’s plot, 1H NMR spectra and mass spectrum. It also exhibits good reusability by alternate addition of Al3+ and EDTA to the AhzF solution. The pH effect tests suggest its good sensitivity from pH 4 to pH 10 and AhzF can recognize labeled Al3+ in tap water directly by naked eyes, which makes it possible for the application in real environment.

Bone repair microspheres have been widely studied due to their convenience during clinical operations. In this study, beta tricalcium phosphate/sodium alginate/poly(D,L-lactic acid) (β-TCP/SA/PDLLA) composite microspheres were successfully prepared using the liquid droplet method. Then, β-TCP/SA/PDLLA composite microspheres were soaked in simulated body fluids (SBF) for 7 days, and tested in an X-ray diffractometer (XRD). The results indicated that sodium alginate (SA) and poly(D,L-lactic acid) (PDLLA) are not limiting factors for the transformation of β-TCP to HA. Since sodium ions and bicarbonate ions were abundant, the final products were not pure HA but (Na, CO3)-substituted HA. When soaked in SBF, the structure of β-TCP/SA/PDLLA composite microspheres remained stable for at least 14 days suggesting that their anti-washout ability was suitable. Furthermore, the absence of calcination during the preparation of β-TCP/SA/PDLLA composite microspheres enabled the easy incorporation of vancomycin into the microspheres in situ at a final embedding ratio of 26.18%. Furthermore, the β-TCP/SA/PDLLA composite microspheres possessed excellent sustained drug release capability, and the release of vancomycin (92.8 wt.%) lasted for almost 168 h. Our results suggest that the β-TCP/SA/PDLLA composite microspheres could be used as a promising graft material particularly for bone repair.

The aim of this study is to characterize plutonium sorption particularly 239Pu distribution coefficients and the influence of pH on sorption processes in saturated geological materials used as a radioactive waste repository in China. The examined geological media is from a southwestern Chinese repository and consists of soil and slates. The backfill material consists of Na-bentonite from Inner Mongolia Gaomiaozi, and will be used at the Beishan high-level waste (HLW) repository, Gansu Province. The results show that the sorption capacity of Pu by geological medium in an acidic environment is low, but significantly increases with increasing pH.

Lactoferrin (LF) was used to assist the synthesis of zinc ferrite (ZnFe 2 O 4 , ZFO) semiconductor photocatalysts in this study, and superparamagnetic ZFO nanocrystals with an average crystallite size ranging from 11.3 nm to 20.1 nm were successfully obtained via the hydrothermal method. It was found that LF was conducive to fast formation of ZFO nuclei, which resulted in remarkable crystallinity enhancement of the as-prepared ZFO nanocrystals. The saturation magnetization ( M s ) of the as-prepared ZFO crystals would be greatly improved with increasing the LF content, and the M s of the as-prepared ZFO crystals synthesized with 50 mg of LF (ZFO-50LF) could reach 19.9 emu/g, whereas the M s of the as-prepared ZFO crystals synthesized in the absence of LF (ZFO-0LF) was only 8.8 emu/g. In addition, although the specific surface area of ZFO-0LF nanocrystals (127.2 m 2 /g) was larger than that of ZFO-50LF nanocrystals (101.6 m 2 /g), and ZFO-0LF exhibited a higher absorption of methyl orange (MO) molecules in contrast with ZFO-50LF, but ZFO-50LF possessed a larger optical absorption coefficient, smaller band gap and higher photocatalytic degradation efficiency per unit area. After being irradiated under UV light for 3 h, ZFO-50LF almost could make MO molecules completely degrade. Therefore, the LF-assisted synthesized ZFO nanocrystals have a promising application prospect to be used as a new high-efficiency recyclable photocatalyst.

Superparamagnetic {\gamma}-Fe2O3 nanoparticles (5 nm diameter) were synthesized in water. The bare particles exhibit good colloidal stability at ~ pH 2 because of the strong electrostatic repulsion with a surface charge of +25 mV. The polyacrylic acid (PAA)-coated particles exhibit remarkable colloidal stability at ~ pH 7 with abundant free carboxyl groups as reactive sites for subsequent functionalization. In this work, we used zeta potential analysis, transmission electron microscopy, small angle X-ray scattering, and Inductively coupled plasma mass spectrometry to investigate the adsorption behavior of U (VI) on bare and coated colloidal superparamagnetic nanoparticles at pH 2 and pH 7. At pH 2, uranyl ion (UO22+) absorbed on the surface of the bare particles with decreasing particle surface charge. This induced particle agglomeration. At pH 7, uranyl ion (UO22+) hydrolyzed and formed plate-like particles of uranium hydroxide that were ~ 50 nm in diameter. The PAA-coated iron oxide nanoparticles absorbed on the surface of these U (VI) hydroxide plates to form large aggregates that precipitate to the bottom of the dispersion. At both pH 2 and pH 7, the resulting U (VI)/nanoparticle complex can be easily collected and extracted from the aqueous environment via an external magnetic field. The results show that both bare and polymer-coated superparamagnetic {\gamma}-Fe2O3 nanoparticles are potential absorbents for removing U (VI) from water.

The ability of bentonite and montmorillonite pillared by Al-oxide and mixed (Ln-Al)-oxides (Ln = La, Ce) to remove 239plutonium solution species from water is comparatively investigated at pH 7 and pH 4. Small-angle scattering and neutron contrast variation with H2O/D2O mixtures is used to verify the ingress of water in the calcined products after hydrophilicity was introduced by an NH3-H2O vapor treatment. The size and shape of the (La/Ce)-Al oxo-hydroxy pillaring cations (2 nm spheres) is determined by small-angle x-ray scattering from the pillaring solutions. Not all of the oxide pillars improved Pu uptake compared with sodium montmorillonite. At neutral and acidic pH only (Ce-Al)-oxide pillared clays showed the ability to remove Pu over the concentration range studied (1.35 × 10−8–8 × 10−8 mol dm−3) with distribution coefficient (KD) values >104. XPS analysis of the (Ce-Al)-oxide pillared clays indicates the presence of Ce4+ as cerium dioxide. The progressive improvement in sorption performance in the order of pillar type Al2O3