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Enantioselective recognition in water remains an ongoing challenge in supramolecular chemistry but is routine in nature. Herein, we report the first enantiopure pair of biomimetic macrocyclic recep...

A selenium-catalyzed trifluoromethylthiolation/[2,3]-sigmatropic rearrangement of tertiary allylic and propargylic alcohols which could provide straightforward and facile access to trifluoromethyl sulfoxides was developed. Various allylic and allenic trifluoromethyl sulfoxides were obtained with moderate to excellent yields. Meanwhile, a Lewis acid mediated trifluoromethylthiolation/1,2-rearrangement to synthesize β-SCF3 carbonyl compounds was also accomplished. These two tandem reactions feature with mild reaction conditions and metal-free. During these two reactions, the chemoselectivity of electrophilic trifluoromethylthiolation was revealed.

Brevibacillus brevis GZDF3 is a gram-positive, plant growth-promoting rhizosphere bacterium (PGPR) isolated from the rhizosphere soil of Pinellia ternata (an important herb in traditional Chinese medicine). The GZDF3 strain produces certain active compounds, such as siderophores, which are the final metabolite products of non-ribosomal peptide synthetase (NRPS) and independent non-ribosomal peptide synthetase (NIS) activity. With the present study, we attempted to investigate the siderophore production characteristics and conditions of Bacillus sp. GZDF3. The antibacterial activity of the siderophores on pathogenic fungi was also investigated. Optimal conditions for the synthesis of siderophores were determined by single factor method, using sucrose 15 g/l, asparagine 2 g/l, 32°C, and 48 h. The optimized sucrose asparagine medium significantly increased the production of siderophores, from 27.09% to 54.99%. Moreover, the effects of different kinds of metal ions on siderophore production were explored here. We found that Fe3+ and Cu2+ significantly inhibited the synthesis of siderophores. The preliminary separation and purification of siderophores by immobilized-metal affinity chromatography (IMAC) provides strong antibacterial activity against Candida albicans. The synergistic effect of siderophores and amphotericin B was also demonstrated. Our results have shown that the GZDF3 strain could produce a large amount of siderophores with strong antagonistic activity, which is helpful in the development of new biological control agents.

An unprecedented three-dimensional multiple hydrogen bonded supramolecular framework containing an interlocked three-fold self-knitting structural topology, which is based on a pseudo graphene-like unweaving monolayer of a Zn(II)-coordination complex, is obtained via a solvothermal synthesis method. Two different large cavities are generated in this supramolecular architecture. Furthermore, the investigation of the Hirshfeld surface analysis reproduces the results of an X-ray crystal structure analysis and expounds the intermolecular interactions experienced by complexes in a visual manner.

In the present work, we have introduced a series of stable radical-doped coordination compounds composed of donor-acceptor structures and shown to produce organic radicals in situ as a result of unconventional lone pair-π interactions in ambient conditions. Inconspicuous lone pair-π and C-Hπ interactions were shown to play a key role in self-assembly as well as the charge transfer process, resulting in a long-lived charge-separated state able to generate organic radicals. The resultant species displayed broad-spectrum antimicrobial activity, including against multi-drug-resistant bacteria. This study unveiled the promise of reactive organic radical-doped materials as a new platform for developing antimicrobial agents that can overcome antibiotic resistance.

A Bronsted acid-catalyzed 1,4-addition hydrothiolation of branched 1,3-dienes was explored for the first time. A solvent-controlled divergent synthesis of sulfides is also disclosed. Use of acetonitrile as a solvent gave allylic sulfides as hydrothiolation products, while thiochromane derivatives (hydrothiolation/Friedel-Crafts products) were obtained using dichloromethane as the solvent. The origin of the regioselectivity of hydrothiolation was explored through density functional theory calculations.

Stimuli-responsive functional materials, especially the light stimulation color change and tunable fluorescent materials, have received considerable attention because of their broad applications in smart materials. Herein, a series of lanthanide-based [Ln = Nd(III) (1), Sm(III) (2), Eu(III) (3), Gd(III) (4), Tb(III) (5), Yb(III) (6), and Lu(III) (7)] crystalline complexes were attained by simply adding the aqueous lanthanide nitrate solution to the water-soluble naphthalenediimide derivative. The obtained lanthanide-based crystalline materials not only show significant photochromism but also possess reactive organic radicals under ambient conditions. Intriguingly, photoswitchable near-infrared (NIR) fluorescence was realized in the crystalline complex 1. The structures of these crystalline materials were systematically studied to clarify the weak interaction-assisted charge-transfer process. The underlying multiple-interaction-assisted supramolecular self-assembly, the radical-doped nature, and the corresponding photochromic mechanism were thoroughly unearthed by single-crystal X-ray diffraction, in situ solid-state UV-vis diffuse reflectance, and electron paramagnetic resonance spectrometric analysis.

Noncovalent interactions, such as π–π stacking interactions, C—H...π interactions and hydrogen bonding, are important driving forces for self-assembly in the construction of functional supermolecules and materials, especially in multicomponent supramolecular systems. Herein, a novel compound based on a π-acidic naphthalene diimide derivative and a double hydroxide-bridged dinuclear Al3+ aqua ion cluster, namely bis[N,N′-bis(2-sulfonatoethyl)-1,4,5,8-naphthalene diimide] di-μ-hydroxido-bis[tetraaquaaluminium(III)] tetrahydrate, (C18H12N2O10S2)2[Al2(OH)2(H2O)8]·4H2O, was obtained using the above-mentioned common noncovalent interactions, as well as uncommon lone-pair–π interactions. Functional molecular modules were connected by these noncovalent interactions to generate obvious photochromic properties. The compound was prepared by the self-assembly of N,N′-bis(2-sulfoethyl)-1,4,5,8-naphthalene diimide and Al(NO3)3·9H2O under mixed solvothermal conditions, and was characterized in detail by single-crystal X-ray diffraction, powder X-ray diffraction and FT–IR spectroscopy. The thermal stability and photochromic properties were also investigated; furthermore, in-situ solid-state UV–Vis absorption spectroscopy and electron spin resonance (ESR) were used to clarify the photochromic mechanism.

Caffeine is a substance that is consumed worldwide, and it may exert neuroprotective effects against various cerebral insults, including neurotrauma, which is the most prevalent injury among military personnel. To investigate the effects of caffeine on high-intensity blast wave-induced severe blast injury in mice, three different paradigms of caffeine were applied to male C57BL/6 mice with severe whole body blast injury (WBBI). The results demonstrated that chronic caffeine treatment alleviated blast-induced traumatic brain injury (bTBI); however, both chronic and acute caffeine treatments exacerbated blast-induced lung injuries and, more importantly, increased both the cumulative and time-segmented mortalities postinjury. Interestingly, withdrawing caffeine intake preinjury resulted in favorable outcomes in mortality and lung injury, similar to the findings in water-treated mice, and had the trend to attenuate brain injury. These findings demonstrated that although drinking coffee or caffeine preparations attenuated blast-induced brain trauma, these beverages may place personnel in the battlefield at high risk of casualties, which will help us re-evaluate the therapeutic strategy of caffeine application, particularly in multiple-organ-trauma settings. Furthermore, these findings provided possible strategies for reducing the risk of casualties with caffeine consumption, which may help to change the coffee-drinking habits of military personnel.

Elevated temperature usually plays a destructive role in supramolecular complexes. At higher temperature, folded proteins tend to unfold and supramolecular assemblies tend to disassemble. In contrast, histidine kinases are able to perform a different function at higher temperature. This results from temperature-induced large amplitude conformational changes. However, similar phenomena have rarely been reported for synthetic receptors. Herein, we report that the conformationally adaptive oxatub[4]arene is able to show a conformational response to temperature change in the presence of an appropriate guest. By employing rotaxane synthesis, the host's conformation in the complex at different temperatures can be fixed. The resulting rotaxanes with different host conformations have been carefully characterized by using 2D NMR spectroscopy, mass spectrometry, and X-ray single crystallography.

Scutellarin plays an anti-tumor role in A549 lung cancer cells, but the underlying mechanism is unclear. In this study, scutellarin was used to treat A549 cells for 12, 24, and 48 h, followed by the addition of Tempo, a selective scavenger of mitochondrial reactive oxygen species (ROS) and SB431542, a transforming growth factor (TGF)-β1 receptor inhibitor. A dihydroethidium fluorescence probe was used to measure the intracellular ROS level, Cell Counting Kit-8 (CCK-8) was used to detect cell viability, and flow cytometry was performed to examine apoptosis. Western blots were used to detect the total protein level of TGF-β1, p-smad2, and cleaved caspase-3 in A549 cells. The results showed that scutellarin significantly inhibited cell viability and increased apoptosis. Scutellarin also promoted intracellular ROS production, TGF-β1/smad2 signaling pathway activation, and cleaved caspase-3 expression, which was partly reversed by Tempo. Moreover, scutellarin-induced intracellular ROS production and cleaved caspase-3 expression were inhibited by blocking the TGF-β1/smad2 pathway with SB431542. In conclusion, scutellarin promoted apoptosis and intracellular ROS accumulation, which could be abrogated by Tempo and SB431542 treatment in A549 cells. Our study indicated that scutellarin induced A549 cell apoptosis via the TGF-β1/smad2/ROS/caspase-3 pathway.

By mimicking the binding motifs of bioreceptors, we have developed a series of multiple functional uranium adsorbents to meet this criterion: positioning direct chelation sites and hydrogen-bonding sites inside deep hydrophobic cavity of naphthalene diimide (NDI) MOFs. Benefiting from well-designed specific microenvironment namely the regular spatial structure and an unusual synergy from hydroxyl and carbonyl groups, the easy-prepared and stable MOF shows enhanced comprehensive performance. Representatively, the MOF CaNDI-oOH shows outstanding performance towards uranium enrichment with chemical and radiation stability, exceptional uptake capacity (572 mg g-1), fast kinetics (within 25 min), high anti-interference ability (the concentration of competitive ions exceeds 10 times), excellent reusability (at least 4 circles). Specifically, this adsorbent is able to reduce uranium in uranium-containing water samples to 3.27 ppb within 30 min, highlighting the potential application in radionuclide removal from wastewater. The experiment results and DFT calculation suggest biomimetic multiple interactions are responsible for high performance uranium capture. The cooperative interactions strategy established here reveals a new paradigm in enhanced uranium extraction for pristine MOFs with limited uranium affinity.

Rotaxane-based molecular shuttles are often operated using low-symmetry axles and changing the states of the binding stations. A molecular shuttle capable of directional shuttling of an acid-responsive cone-like macrocycle on a single-state symmetric dumbbell axle is now presented. The axle contains three binding stations: one symmetric di(quaternary ammonium) station and two nonsymmetric phenyl triazole stations arranged in opposite orientations. Upon addition of an acid, the protonated macrocycle shuttles from the di(quaternary ammonium) station to the phenyl triazole binding station closer to its butyl groups. This directional shuttling presumably originates from charge repulsion and an orientational binding preference between the cone-like cavity and the nonsymmetric phenyl triazole station. This mechanism for achieving directional shuttling by manipulating only the wheels instead of the tracks is new for artificial molecular machines.

Positive cooperativity achieved through activating weak non-covalent interactions is common in biological assemblies but is rarely observed in synthetic complexes. Two new molecular tubes have been synthesized and the syn isomer binds DABCO-based organic cations with high orientational selectivity. Surprisingly, the ternary complex with two hosts and one guest shows a high cooperativity factor (α=580), which is the highest reported for synthetic systems without involving ion-pairing interactions. The X-ray single-crystal structure revealed that the strong positive cooperativity likely originates from eight C-H⋅⋅⋅O hydrogen bonds between the two head-to-head-arranged syn tube molecules. These relatively weak hydrogen bonds were not observed in the free hosts and only emerged in the complex. Furthermore, this complex was used as a basic motif to construct a robust [2+2] cyclic assembly, thus demonstrating its potential in molecular self-assembly.

Two new naphthotubes with ester linkers were synthesized and characterized. With the syn isomers of an ester naphthotube and an ether naphthotube, strong positive allosteric cooperativity in a ternary complex with two different hosts on one guest was achieved. This paves the way to construct robust supramolecular architectures with high complexity and diversity.

Naphthalene diimides (NDIs) are an interesting class of electron-poor organic dyes but with weak emissions that limit their applications. Recently several examples have demonstrated that self-assembly of such weak emissive NDIs into some special aggregates could enhance their emissions. However, a detailed emission mechanism remains unexplored due to the lack of structural evidences. In order to go deep into the emissive mechanism and in turn guide material design, it is necessary to learn the molecular arrangement in the aggregates. For this purpose, in this paper we used a crystal engineering strategy to explore the structure-property relationships between the molecular packing and emissive properties of NDI derivatives in crystalline state, which revealed that the small slipped cofacial π-π stacking of NDI cores in the solid states answered for their enhanced emission behaviors. This observation has an extensive applicability and practical significance for design of NDI based aggregation-induced emission materials.

Dissolved organic carbon (DOC) is an important component of the terrestrial carbon cycle. However, the sources and controlling factors of DOC in soils remain uncertain. In this study, the effects of nitrogen (N) amendment and crop growth on DOC in soil solution were examined at a maize-wheat rotated field located in the central Sichuan Basin in southwestern China. Nitrogen treatments in this study included 150 kg N ha(-1) season(-1), 200 kg N ha(-1) season(-1) and the control without any fertilizer application. During the whole experimental period, we observed significant decreases (p < 0.05) in DOC concentrations in the sampled soil solutions associated with increase in N inputs at the bare soil plots, but no change in DOC at the plots with crop growth. The estimated average contributions of plantderived DOC were 16%, 24% and 32% of total DOC in the summer maize season and 21%, 32% and 38% in the winter wheat season along with the gradient of N fertilizer application rates. The results implied that the crop growth could play a key role in the soil DOC production, and the N input enhanced DOC production by increasing crop growth. The relationship between the DOC concentrations and the crop root biomass was statistically significant for both the maize and winter wheat seasons. Our observations indicated that crop growth exerted greater influence on the seasonal variability of DOC concentration in soil solutions at the experimental site, which overwhelmed the effect of soil native organic matter decomposition on DOC concentrations in soil solutions.

During the last half a century, great achievements have been made in molecular recognition in parallel with the invention of numerous synthetic receptors. However, the selective recognition of hydrophilic molecules in water remains a generally accepted challenge in supramolecular chemistry but is commonplace in nature. In an earlier Communication [ Huang et al. J. Am. Chem. Soc. 2016 , 138 , 14550 ], we reported a pair of endo-functionalized molecular tubes that surprisingly prefer highly hydrophilic molecules over hydrophobic molecules of a similar size and shape. The hydrophobic effect and hydrogen bonding were proposed to be responsible, but their exact roles were not fully elucidated. In this Article, we present a thorough study on the binding behavior of these molecular tubes toward 44 hydrophilic molecules in water. Principal component analysis reveals that the binding strength is weakly correlated to the hydrophobicity, volume, surface area, and dipole moment of guests. Furthermore, molecular dynamics simulations show the hydrophobic effect through releasing the poorly hydrogen-bonded cavity water contributes to the binding of all the hydrophilic molecules, while hydrogen bonding differentiates these molecules and is thus the key to achieve a high selectivity toward certain hydrophilic molecules over other molecules with a similar size and shape. Therefore, a good guest for these molecular tubes should meet the following criteria: the hydrogen-bonding sites should be complementary, and the molecular volume should be large enough to expel all the cavity water but not too large to cause steric hindrance. This rule of thumb may also be used to design a selective receptor for certain hydrophilic molecules. Following these guidelines, a "best-fit" guest was found for the syn-configured molecular tube with a binding constant as high as 10

A rigid molecular cleft shows unique aggregation-induced emission (AIE) by restricting the motion of aldehyde through intermolecular lone pair⋅⋅⋅π interactions, which are tuned by side chains. This AIE luminogen was demonstrated to work as a fluorescent sensor for aniline and an optical chirality sensor for chiral amine.

Dissipative self-assembly is common in biological systems, where it serves to maintain a far-from-equilibrium functional state through fuel consumption. Synthetic dissipative systems have been prepared that can mimic some of the properties of biological systems, but they often show poor mechanical performance. Here, we report a shear-induced transient hydrogel that is highly stretchable. The system is constructed by adding Cu(II) into the aqueous solution of a pseudopolyrotaxane, which is itself formed by threading molecular tubes on polyethylene glycol chains. Vigorous shaking transforms the solution into a gel, which gradually relaxes back to the sol state over time. This cycle can be repeated at least five times. A mechanism is proposed that relies on a shear-induced transition from intrachain to interchain coordination and subsequent thermal relaxation. The far-from-equilibrium hydrogel is highly stretchable, which is probably due to 'frictional' sliding of the molecular tubes on the polyethylene glycol chains. On shaking, the hydrogel undergoes fast self-healing.

The p53 gene contains homozygous mutations in ~50-60% of human cancers. About 90% of these mutations encode missense mutant proteins that span ~190 different codons localized in the DNA-binding domain of the gene and protein. These mutations produce a protein with a reduced capacity to bind to a specific DNA sequence that regulates the p53 transcriptional pathway. Eight of these mutations are localized in codons that account for ~28% of the total p53 mutations and these alleles appear to be selected for preferentially in human cancers of many tissue types. This article explores the question 'Why are there hotspot mutations in the p53 gene in human cancers?' Four possible reasons for this are considered; (1) the hotspot mutant alleles produce a protein that has a highly altered structure, (2) environmental mutagens produce allele-specific changes in the p53 gene, (3) these mutations arise at selected sites in the gene due to a specific DNA sequence, such as a methylated cytosine residue in a CpG dinucleotide, which has a higher mutation rate changing C to T nucleotides, (4) along with the observed change in mutant p53 proteins, which produce a loss of function (DNA binding and transcription), some mutant proteins have an allele-specific gain of function that promotes cancer. Evidence is presented that demonstrates the first three possibilities all contribute some property to this list of hotspot mutations. The fourth possibility remains to be tested.

A facile method for the selective synthesis of pillar[6]arenes has been developed. Due to a strong electron donor-acceptor interaction between the electron-deficient naphthalene diimide and a precursor for the pillararene, 1,4-diisobutoxy-2,5-bis(methoxymethyl) benzene, naphthalene diimide has been demonstrated to act as a template for selective synthesis of pillar[6]arene in a modest yield (30%).

Core-substituted naphthalene diimides are attracting much interest because of their tunable optical properties, which are generally achieved by the elaborate introduction of electron-donating groups into electron-deficient core to form donor–acceptor compounds through the covalent bonds. Here we report that the optical properties of core-unsubstituted naphthalene diimides can be modulated by a facile cocrystal strategy. Based on the X-ray crystallographic and Hirshfeld surface analyses, the π–π interactions have been demonstrated to be the most important factor that answers for the optical properties of naphthalene diimide cocrystals, while other interactions, such as hydrogen bonds and solvation effects, have little impact on their properties but influence π stacking. This insight is of considerable significance for the development of naphthalene diimide based materials in various directions.

The electronic structure and chemical bonding of LiFePO4 were calculated using maximally-localized Wannier functions within the framework of the first-principles method. Comparison of the shifts in Wannier centers between LiFePO4 and delithiated reference (FePO4)r structures demonstrated the unstable chemical bonding of Fe–O1 and Fe–O2 during delithiation. The contribution of each orbital to the small-polaron polarization field was discussed in detail. The small polaron hopping is accompanied by a very small polarization field with the value of 0.049 C/m2. Results of our calculations showed that the chemical bonding of Fe–O3 has an important function in the low-temperature conductivity of LiFePO4.

In this research, we report the regioselective synthesis of methylene-bridged naphthalene oligomers from 2,6-dialkoxyl naphthanene and paraformaldehyde by using p-TsOH as the catalyst and CH2Cl2 as the solvent. The structures were characterized by NMR spectroscopy and X-ray crystallography. Their host-guest chemistry with organic cations was studied, and optimal naphthalene numbers in the oligomers were revealed for different guests. In addition, the reason for the unsuccessful synthesis of methylene-bridged naphthalene macrocycles was discussed.

Chiral epoxides are important intermediates in chemistry and biology. The high-throughput screening of asymmetric epoxidation conditions requires fast determination of the absolute configurations and ee values of chiral epoxides. Herein, we report molecular recognition and chiroptical sensing of epoxides in water using endo-functionalized molecular tubes. The absolute configurations and ee values were simultaneously determined by circular dichroism spectroscopy. In addition, real-time monitoring as well as the application to real asymmetric epoxidation was demonstrated. The method is simple, environmentally friendly, and amenable to high-throughput screening.

Objective.Patients with an HLA-B*58:01 allele have an increased risk of developing severe cutaneous adverse drug reactions (SCAR) when treated with allopurinol. Although one-off pharmacogenetic testing may prevent life-threatening adverse drug reactions, testing prior to allopurinol initiation incurs additional costs. The study objective was to evaluate the cost-effectiveness of HLA-B*58:01 screening compared with using other available urate-lowering agents (ULA).Methods.A decision-analytical model was used to compare direct medical costs and effectiveness [including lifetime saved, quality-adjusted life-yrs (QALY) gained] in treating new patients with the following options: (1) genetic screening followed by allopurinol prescribing for noncarriers of HLA-B*58:01, (2) prescribing benzbromarone without screening, (3) prescribing febuxostat without screening, and (4) prescribing allopurinol without screening. A 1-year time frame and third-party payer perspective were modeled for both the entire cohort (base-case) and for the subgroup of patients with chronic kidney disease (CKD).Results.The incremental cost-effectiveness ratio of genetic screening prior to ULA therapy was estimated as New Taiwan (NT) $234,610 (US$7508) per QALY gained in the base-case cohort. For patients with CKD, it was estimated as NT$230,925 (US$7390) per QALY. The study results were sensitive to the probability of benzbromarone/febuxostat-related hypersensitivity, and a negative predicted value of genotyping.Conclusion.HLA-B*58:01 screening gave good value for money in preventing allopurinol-induced SCAR in patients indicated for ULA therapy. In addition to the costs of genotyping, it is important to monitor ULA safety closely in adopting HLA-B*58:01 screening in practice.

Excitable reaction-diffusion systems form a wealth of dissipative concentration patterns that exist not only in chemical systems but also control or disrupt biological functions. An important example are rotating spiral waves in the autocatalytic Belousov-Zhabotinsky reaction. We show that the viscosity of this system can be increased by the addition of the polymer xanthan gum. In the resulting system, we pin spiral waves to a thin glass rod and then reposition the vortex centers by a linear motion of the heterogeneity. The Stokes flow generated by this motion can be a weak perturbation to the wave pattern and follows a simple, analytical expression. Numerical simulations of a corresponding reaction-diffusion-flow model reproduce the experimental observations and show that the spatial extent of the flow field can vary widely around the characteristic wavelength of the spiral. We find that a sharp spatial decay of the flow pattern corresponds to our experimental observations, whereas more expansive flow fields surprisingly allow the repositioning of spiral tips at speeds faster than the wave velocity.

An efficient planar π-acid electron transfer organocatalyst based on electron-deficient substituted naphthalene diimide has been developed for oxidative C–C coupling of 2,6-di- tert -butylphenol to its dimeric derivative or unexpected ring-rearranged trimeric quinone methide by controlling the reaction temperatures.

Eu-doped calcium aluminate was synthesized via the low-cost self-propagating combustion synthesis (SPCS) technique, whose phase constitutions were identified as Ca9Al6O18 and Ca3Al2O6. The Ca2+ ions in Ca9Al6O18 rather than Ca3Al2O6 phase were replaced by Eu3+ ions. The product exhibits the superior luminescent property and photocatalytic activity, which may find potential applications in the display devices and environment treatments.

Multiferroic BiFeO 3 (bismuth ferrite, BFO) ceramics were sintered using a rapid heating and quenching technique in an atmosphere of argon or oxygen. The resulting ceramics were phase pure with the space group R 3 c . BFO ceramics sintered under an argon atmosphere contained more oxygen vacancies and Fe 2+ ions compared with those sintered under an oxygen atmosphere, which resulted in high dielectric loss and large dielectric dispersion. It confirms that the unavoidable Fe 2+ ions may play a fundamental role in these special materials, such as in the evaporation of the Bi component and valence change of the Fe component. This work also discusses the dielectric response mechanism in BFO ceramics.

SrBi2Ta1.6Nb0.4O9 (SBTN) and SrBi2Ta2O9 (SBT) ceramics with typical bismuth layered perovskite structure were synthesized by hot-press sintering at 1000 °C for 2 h. The maximum relative density of as-sintered SBTN and SBT materials is 98.97%. The domain structure of SBTN and SBT was systemically characterized by means of TEM and HRTEM. The 90° domain walls were identified by the 90° rotation relationship of the electron diffraction pattern along the [0 0 1] zone axis. Irregular shaped and highly curved 180° domain wall were also observed in SBTN ceramics. The traditional α-fringes can be found in SBT, which are the evidence of large strains in hot-press sintering ceramics. Rod-like SrTa2O6 precipitates are also analyzed as well as its interface with the matrix.

We report the synthesis of perovskite ferroelectric nanowire strontium bismuth tantalate (SrBi 2 Ta 2 O 9 , SBT). Sol–gel techniques have been used. The morphology and structures are analyzed via SEM, TEM and XRD. The XRD and TEM analysis show that the structure of SBT nanowires is single orthorhombic perovskite with A2 1 am structure space group. The obtained SBT nanowires with an average length of 35 μm and a diameter of 200 nm are c-axis preferred orientation in the templates. The formation mechanism of SBT nanowires with complex crystal structure was discussed.

We report the independent invention of perovskite ferroelectric nanowires strontium bismuth tantalate (SrBi2Ta2O9, SBT). Electrophoretic sol–gel techniques have been used successfully. The morphology and structures are analyzed via SEM, TEM and XRD. SBT nanowires and nanoparticles filled template revealed 30 and 40 μm long, respectively. SBT are proved to be a single phase of orthorhombic perovskite structure. As it indicated, SBT nanowires has been crystallized at 700 °C. To minimize surface polarity, SBT nanowires oriented preferentially along the growing axis (c axis) by translation and rotation of atomic clusters of SBT.

Silica microspheres that are half-coated with platinum metal undergo self-propulsion in solutions of H(2)O(2), with the average speed increasing with increasing H(2)O(2) concentration. Microscopic observation of the particle motion, with segmentation of the image data, demonstrates that the particles move, on average, with the platinum-coated region oriented opposite to the direction of motion. Velocity autocorrelation and motion direction analyses show that the direction of motion is highly correlated with the particle orientation. The effect of the observation time interval on the measured translational diffusion coefficient and the apparent particle motion is analyzed.

The present investigation reports on the preparation of BiFeO3 nanopowders by a sol-gel method using acetylacetone as a stabilizer. Single-phase BiFeO3 nanopowders without any impurity or amorphous phases were obtained when the precursor was thermal treated at temperatures as low as 400 oC for 2 h. Acetylacetone (acac) plays an important role on lowering the formation temperature of pure phase BiFeO3 nanopowders. It is found that Bi/acac molar ratio of 1/30 was favorable for a stable sol and for the lowest crystallization temperature of pure BiFeO3 nanopowders. X-ray diffraction and Fourier transform infrared spectroscopy revealed that thermally induced crystallization process of BiFeO3 nanopowders from Bi-Fe polymeric precursor. When the thermal treated temperature was below 200 oC, only amorphous phase existed. With the temperature increasing up to 300 oC, crystallized phase, carbonate, were detected. After annealed at 400 oC, Bi-Fe precursor totally changed to rhombohedral BiFeO3 nanopowders. Scanning electron microscopy characterized morphologies of BiFeO3 nanopowders calcined at 400 oC and 500 oC. The ferroelectric transition of BiFeO3 nanopowders at 827 oC has been detected by differential thermal analysis.

Bismuth ferrite powders were synthesized by a simple sol–gel method at the temperature as low as 450 °C. Single phase BiFeO3 powders with a rhombohedral perovskite structure were fabricated after Bi–Fe gels were calcined at 450–650 °C. Atomic ratio of Bi to Fe is approximately 1:1 for BiFeO3 powders, as determined by energy dispersive X-ray spectrometer. BiFeO3 powders show weak ferromagnetism at room temperature and strong size-dependent magnetic properties, which is different from the linear M–H relationship in BiFeO3 ceramics. Dielectric anomaly at round 330 °C near the magnetic transition point corresponds to the antiferromagnetic to paramagnetic phase transition, indicating the coupling between polarization and magnetization in BiFeO3 powders. A reversible ferroelectric phase transformation of BiFeO3 powders has been detected at 827 °C by a differential thermal analysis.

BiFe1− x Ta x O3 (x = 0, 0.05, 0.1) nanopowders have been fabricated by a simple sol–gel method. Dielectric measurements at microwave frequencies (2–18 GHz) were made using a vector network analyser. Without tantalum, the BiFeO3 nanopowder presents a relaxation-like response with a characteristic frequency of 15 GHz, which can be associated with an overdamped process. The Ta-doped nanopowders, however, show resonant behaviour with resonant frequencies of 12.5 and 14.6 GHz. The intensity of the resonant peak near 14.6 GHz decreases with increasing Ta addition. This behaviour is associated with a damped resonance process. Room-temperature magnetic measurements indicate that the addition of Ta influences the magnetic properties of the BiFeO3 nanopowders, with BiFe0.95Ta0.05O3 having the strongest ferromagnetism with a saturation magnetisation M s of about 0.05 µB/Fe. The origin of the enhanced ferromagnetism is possibly associated with the distortion of the oxygen octahedral by the Ta substitution or/and the...

We present a facile sol–gel route to synthesize lanthanum-substituted bismuth titanate (BLT). The chemical reactions and crystallization process of this method using the initial materials of bismuth subnitrate [4BiNO3(OH)2·BiO(OH)], lanthanum nitrate [La(NO3)3·6H2O] and tetrabutyl titanate [Ti(C4H9O)4] were investigated by thermogravimetric and differential thermal analysis, IR spectroscopy, gas chromatography/mass spectrometry, Raman spectroscopy and XRD. The evaporation of the dissolved CO2 in the amorphous BLT matrix is associated with the crystallization of BLT. The BLT gel is pure BLT perovskite when calcination temperature is higher than 500 °C. The grain size of the obtained nanoparticles ranges from 15 to 82 nm. The Arrhenius curve is obtained from the representation of the reduced sizes with respect to the calcination temperature. The activation energy of grain growth in BLT nanoparticles is 0.36 eV, which shows a rapidly growth process in the temperature range of 500–850 °C.

The nucleocapsid protein (N) is a major structural protein of coronaviruses. The N protein of bat SARS-like coronavirus (SL-CoV) has a high similarity with that of SARS-CoV. In this study, the SL-CoV N protein was expressed in Escherichia coli , purified and used as antigen. An Indirect Enzyme-Linked Immunosorbent Assay (indirect ELISA) was developed for detection of SARS-or SL-CoV infections in bat populations. The detection of 573 bat sera with this indirect ELISA demonstrated that SL-CoVs consistently circulate in Rhinilophus species, further supporting the proposal that bats are natural reservoirs of SL-CoVs. This method uses 1-2 μl of serum sample and can be used for preliminary screening of infections by SARS-or SL-CoV with a small amount of serum sample.

Bismuth ferrite (BiFeO 3 ) nanopowders were synthesized by a sol–gel method at the temperature as low as 450 °C. The obtained sol was transparent and homogenous when the mixture ionic concentration was properly controlled with the help of ethylene alcohol. The preparation process of crystalline BiFeO 3 could be divided into three stages: (i) the evaporation of organics and decomposition of nitrogen-containing organics below 200 °C; (ii) the collapse of Bi–Fe gel network in the temperature range of 200–300 °C and (iii) the formation of BiFeO 3 nanopowders by the solid-state reaction between Bi 2 CO 3 O 2 and Fe 2 O 3 .

A series of methylcellulose (MC) samples were successfully synthesized using dimethyl sulphate (DMS) as a methylation reagent in 7 wt% NaOH/12 wt% urea aqueous solution through controlling the reaction conditions. The MC samples were characterized with 1H and 13C NMR, gas chromatography (GC), ultraviolet spectroscopy, viscometry and solubility measurement. Analysis of GC showed that there were no unsubstituted anhydroglucose units (AGU) and few completely substituted AGU along the molecular chains of the MC samples, and there was a uniform distribution of methyl substitution along the MC molecular chains. The stability of 7 wt% NaOH/12 wt% urea solution for the methylation of cellulose was investigated for the first time. The results showed 2 wt% cellulose solution in the 7 wt% NaOH/12 wt% urea solvent was almost stable at room temperature, and little decomposition of the cellulose molecular chains occurred during the methylation reaction.

A novel sol–gel process has been successfully developed for preparing strontium bismuth tantalate (SrBi2Ta2O9, known as SBT) with ethylene alcohol as a solvent and acetic acid as a catalyst. The size of phase-pure SBT nanoparticles could be 4 nm in diameter by avoiding the formation of the fluorite phase at the low temperatures (550–600∘C). The behavior of the crystallization in SBT is investigated by XRD, TG-DTA, FT-IR and TEM. The nanoparticle size as a function of the annealing temperature is also investigated. By fitting the Arrhenius curve, we obtain the crystalline and vitreous growth activation energies, i.e, Ea1 = 0.709 eV and Ea2 = 0.093 eV. The two other fitting parameters, transition temperature T0 = 814 K (541∘C) and transition width Δ = 0.022, directly show the behavior of the phase transition from vitreous phase to crystalline phase.

Grass carp hemorrhage virus (GCHV), a member of Reoviridae, causes severe hemorrhagic disease of grass carp (Ctenopharyngodon idellus) in China. Icosahedral virions of GCHV were used as to assay the effect of specific peptides for the inhibition of GCHV infectivity. A random nona-peptide library displayed on phage fUSE5 was constructed, and the expressed peptides were fused onto the amino terminus of the minor coat protein III. By biopanning, the fused peptides were bound to the biotinylated GCHV. Phages containing specific peptides bound to GCHV were eluted and amplified in Escherichia coli K91. Three rounds of affinity selection enriched the pool of inhibiting peptides. Sixteen clones which inhibited the replication of GCHV in a grass carp kidney cell line were selected. The TCID(50) of GCHV was decreased over 10000x. Six clones having the strongest inhibitory effect shared the same DNA sequence, with a deduced amino acid sequence of NH(2)-Leu-Trp-Val-Gly-Gly-Gly-Arg-Asn-Ala-COOH. A synthesized nona-peptide of identical sequence exhibited similar inhibitory activity towards GCHV replication in vitro.

SrBi2(Ta1-xNbx)2O9(SBTN) ferroelectric ceramics with typical bismuth layered perovskite structure were synthesized with a reactive hot-press sintering process at 1000°C for 2h. The as-sintered SBTN (x=0.2, 0.4, 0.6, 0.8) materials had a maximum relative density of 95.97%. Bi-layered perovskite structure was obtained. The grain sizes increased with increasing Nb content. In 1MHz frequency, remanent polarization (Pr) of SBTN (x=0.2, 0.4, 0.6, 0.8) were 10.0, 3.0, 1.7 and 1.0, while coercive field (Ec) of SBTN (x=0.2, 0.4, 0.6, 0.8) were 50, 32, 33 and 33kV/cm, respectively.

Hydroxyapatite (HA)/titanium (Ti) composites were successfully fabricated by hot isostatic pressing at 850°C. The microstructure of 7T2HB (70Ti+20HA+10Bioglass, Vol. %) composites were systematically investigated. The main constituents of the composites are hydroxyapatite and titanium. A simulated body fluid (SBF) with the same ion concentrations as those of human plasma and pH value of 7.4 is selected to evaluate the in vitro biological properties of the composites. After 2-week immersion in SBF, the bioactive apatite formed a very dense film on the surface of the composites. The dissolution of CaO and Ca-P compounds in SBF improves the growth of apatite on the surface of the composites.