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For the safety assessement of deep geological repository for high-level radioactive waste, radionuclides transport behavior in rock systems is necessary to clairify and establish a suitable model. The advection–dispersion experiments(ADEx) was effectively designed to inadequate transport models through a calibration/validation process, and HTO, selenate (VI) and selenite (IV) migration behavior on crushed granite was studied by a high reliable and dynamic column device to obtailned retardation factor (R) and the dispersion coeffcient (D) by fitting experimental breakthrough curves (BTCs) in a various range of flow rates. Moreover, it showed the similar results between the BTCs of HTO and Se(VI) by fitting a equlibrium model due to no retardation effect. In fact, there was a relatively obvious sorption of Se(IV) in BTCs by fitting a retardation factor (R) value higher than 1. In addition, the two sites non-equilibrium model with a lowest root mean square error were applied to realize Se(IV) sorption mechanism on granite.

The adsorption and activation of CO2 molecules on the surface of photocatalysts are critical steps to realize efficient solar energy-induced CO2 conversion to valuable chemicals. In this work, a defect engineering approach of a high-valence cation Nb-doping into TiO2 was developed, which effectively enhanced the adsorption and activation of CO2 molecules on the Nb-doped TiO2 surface. A highly ordered Nb-doped TiO2 nanotube array was prepared by anodization of the Ti-Nb alloy foil and subsequent annealing at 550 °C in air for 2 h for its crystallization. Our sample showed a superior photocatalytic CO2 reduction performance under simulated solar illumination. The main CO2 reduction product was a higher-energy compound of acetaldehyde, which could be easily transported and stored and used to produce various key chemicals as intermediates. The acetaldehyde production rate was over ∼500 μmol·g-1·h-1 with good stability for repeated long-time uses, and it also demonstrated a superior product selectivity to acetaldehyde of over 99%. Our work reveals that the Nb-doped TiO2 nanotube array could be a promising candidate with high efficiency and good product selectivity for the photocatalytic CO2 reduction with solar energy.

Supramolecular hydrogels derived from natural biomolecules have promising applications for drug delivery due to their inherent biocompatibility and tunable responsiveness to various stimuli. However, conventional hydrogels only modulate the release kinetics roughly to achieve sustained drug release, exhibiting fast-then-slow release behavior without on/off control. Herein, a guanosine (G)-quartet·Na+-borate supramolecular hydrogel (GB hydrogel) cross-linked via a guanosine-borate diester and intertwined by G4-nanofibres formed by π-π stacking of G4-quartets stabilized by Na+ is developed for on-demand release of Acyclovir (Acv). This GB hydrogel is facilely prepared by a one-pot hierarchical assembly involving hydrogen bonds, dynamic borate ester bonds and cation coordination, which endow it with tunable mechanical properties, excellent self-healing properties and reversible degradation behavior in response to pH, glucose and ion concentration. Benefiting from that the guanosine analog Acv is able to assemble into a G4-quartet by replacing guanosine via reversible hydrogen bonding, the Acv-loaded GB hydrogel showed favorable stability in physiological medium without undesired release and achieved external stimulus-triggered on-demand release with switchable on/off control and tunable release kinetics. Moreover, the GB hydrogel also exhibited excellent in vitro and in vivo biocompatibility. Such a natural nucleoside-based supramolecular hydrogel with on-demand drug release, self-healing property, biodegradability and biocompatibility provides a precisely controlled paradigm to overcome early burst release behavior of conventional hydrogels for the development of injectable hydrogel delivery systems.

Lignin nanoparticles (LNPs), as a special aggregate of renewable and biodegradable lignin available in abundant amounts, are a perfect building-block material because of their advantages, including...

An accurate and effective method combining ion chromatography (IC) and inductively coupled plasma optical emission spectrometry (ICP-OES) was applied in this work to qualitatively and quantitatively analyze individual and co-existing iodide (I−) and iodate (IO3−) at various concentrations. More specifically, a very strong linear relationship for the peak area for the co-existing I− and IO3− ions was reached, and a high resolution value between two peaks was observed, which proves the effectiveness of our combined IC-ICP-OES method at analyzing iodine species. We observed lower accessible porosity for the diffusion of both I− and IO3− in samples of bentonite clay using IC-ICP-OES detection methods, where the effective diffusion coefficient varied based on the anion exclusion effect and the size of the diffusing molecules. In fact, the distribution coefficients (Kd) of both I− and IO3− were close to 0, which indicates that there was no adsorption on bentonite clay. This finding can be explained by the fact that no change in speciation took place during the diffusion of I− and IO3− ions in bentonite clay. Our IC-ICP-OES method can be used to estimate the diffusion coefficients of various iodine species in natural environments.

Various numerical methods have been being extensively used to estimate the diffusion parameters of pertechnetate (99TcO4−) in compacted MX80 bentonite clay using through-diffusion (TD) techniques. In this study, an improved TD column test was applied, and the diffusion fluxes of tritium (HTO) as a non-reactive radionuclide, and 99TcO4− with various dry densities, were compared under the same experimental conditions. Similar results were obtained for the apparent diffusion coefficients of HTO and 99TcO4− using three estimation methods: a graphical method applying the asymptote calculation, an analytical solution using Lsqcurvefit installed in MATLAB, and the Marquardt–Levenberg optimization algorithm in the HYDRUS-1D inverse method. The statistical analysis showed that the densities using a one-way analysis of variance (ANOVA) for the three estimation methods ranged from 1200 to 2000 kg/m3, which indicated that there were no obvious differences between HTO and 99TcO4−. In general, the diffusion parameters of 99TcO4− were lower than those for HTO due to anion exclusion effects and lower accessible porosity.

Silicon shows potential as an anode material in lithium ion batteries due to its high specific capacity, yet its considerable volume expansion during lithiation leads to fracture and pulverization. Unfortunately, neither the atomic-level structural evolution, nor the mechanical behavior of the anode during lithiation and delithiation cycles is well understood. Interestingly, the lithiation process of a-Si provides an interesting continuum from open-structured network glass to densely-packed atomic glass, which could be used to obtain useful insights regarding commonalities in glasses. Here atomic level simulation has been used to investigate one cycle of lithiation and delithiation of amorphous silicon electrode, using Grand Canonical Monte Carlo (GCMC) and molecular dynamics (MD) simulations. The atomic level structural transformation and damage accumulation of the anode during cycling has been systematically analyzed, as well as their mechanical responses in compact tension tests. There appears to be a ductile-brittle-ductile transition for the amorphous silicon anode during both the lithiation and delithiation cycle. In other words, amorphous silicon is particularly vulnerable at intermediate lithiation. The fracture behavior of lithiated silicon was found to correlate to the Poisson's ratio, due to variations in bond covalency and structural disorder.

Atrophic age-related macular degeneration (AMD) is the most common type of AMD, yet there is no United States Food and Drug Administration (FDA)-approved therapy. This disease is characterized by retinal pigment epithelial (RPE) insufficiency, primarily in the macula, which affects the structure and physiology of photoreceptors and ultimately, visual function. In this study, we evaluated the protective effects of a naturally derived small molecule glycan therapeutic-asialo-, tri-antennary complex-type N-glycan (NA3)-in two distinct preclinical models of atrophic AMD. In RPE-deprived Xenopus laevis tadpole eyes, NA3 supported normal retinal ultrastructure. In RCS rats, NA3 supported fully functioning visual integrity. Furthermore, structural analyses revealed that NA3 prevented photoreceptor outer segment degeneration, pyknosis of the outer nuclear layer, and reactive gliosis of Müller cells (MCs). It also promoted maturation of adherens junctions between MC and photoreceptors. Our results demonstrate the neuroprotective effects of a naturally derived small molecular glycan therapeutic-NA3-in two unique preclinical models with RPE insufficiency. These data suggest that NA3 glycan therapy may provide a new therapeutic avenue in the prevention and/or treatment of retinal diseases such as atrophic AMD.

Ternary nickel-cobalt compounds with nano-arrayed structures can be used as promising electrodes to obtain high-performance electrochemical energy storage devices. Thus, ternary nickel-cobalt selenide, (NixCo1-x)0.85Se, nanosheet arrays are successfully synthesized via a two-step method consisting of hydrothermal and cation-exchange process, then directly used as binder-free electrodes for supercapacitors. Characterization results indicate that the morphologies and chemical composition of (NixCo1-x)0.85Se can be regulated by altering the reaction time. Electrochemical tests suggest that (Ni0.5Co0.5)0.85Se nanosheet arrays possess the best electrochemical properties, i.e.: a maximum specific capacity of 430.87 mA h g−1 at 1 A g−1 and good cycling stability with 85.25% capacity retention after 3000 cycles. In addition, hybrid supercapacitors based on (Ni0.5Co0.5)0.85Se nanosheet arrays and nitrogen-doped porous carbon can deliver a high energy density of 70.58 Wh kg−1 at power density of 320.02 W kg−1, as well as 91.88% capacitance retention after 8000 cycles, indicating that (Ni0.5Co0.5)0.85Se nanosheet arrays has higher applicable value in energy-storage fields.

Dopamine (DA), a typical catechol-containing monomer, which has been well reported for its excellent applications in biomedical research, was used to modify alginate (ALG) hydrogel for better gel formation and performance which are needed for drug delivery. By our design, Polydopamine (PDA) particles embedded ALG hydrogel (ALG-PDA), two types of DA and ALG co-polymerized hydrogels (ALG-DA-AS, ALG-DA-SP) which were initiated by ammonia aqueous solution (AS) and sodium periodate (SP), respectively, were successfully prepared. The status of incorporated DA/PDA and their interactions with hydrogel skeleton were investigated by chemical structure, morphology and rheology characterizations. Interestingly, a self-gelation process was discovered during ALG-DA-SP preparation, which is supposed to be the crosslinking formation via the aromatic interaction and hydrogen bonding between catechol or o-benzoquinone modified ALG molecules. Such self-crosslinked structure was proved helpful to improve the structural stability of gel even in saline environment. The effects of DA, SP concentration on the self-gelation process were discussed. The good biocompatibility of PDA material was also confirmed by a cytotoxicity test. In loading and release experiments, all the modified hydrogels were proved to have better adsorption ability to gatifloxacin (GFLX) and more steady in vitro release behavior than pristine ALG hydrogel.

How to overcome multiple obstacles to achieve the efficient and safe delivery of therapeutic genes is still the key to gene therapy. To address this issue, a cationic carrier consisting of polyamide-amine (HPAA-peptide-Fc) modified by an enzyme-responsive polypeptide as the core and hyperbranched polyglycerol derivative (CD-HPG) as the shell was synthesized by self-assembly. The obtained HPAA-peptide-HPG could form the compact nanocomplex with siPlk1, thus confirming the stable load of genes and subsequent targeted gene delivery. And the nanogenes could significantly induce apoptotic effect via the down-expression of Plk1 protein in breast cancer cells. Moreover, compared to polyethylenimine, HPAA-peptide-HPG exhibited superior biocompatibility through hemolysis and cell viability assays because of the shielding function of CD-HPG, thereby being beneficial to increasing the circulation time of the complex when administrated in vivo. Such an efficient and safe gene delivery complex (HPAA-peptide-HPG) presents a good example of rational design of cationic supramolecular vesicles for stimulus-responsive siRNA transport, which should be encouraged in cancer gene therapy.

Introducing porosity is attractive for tailoring electronic, thermal, and mechanical properties of inorganic materials. Nanoporosity is typically either inherent in crystallographic channels in the structure or obtained by external templating during synthesis and sintering. However, controllably engineering porosity in materials with laminated crystal structures without channels remains a challenge. Here, we demonstrate the realization of faceted and oriented nanopores in textured Ca3Co4O9-a laminated ceramic with a misfit-layered structure of importance for thermoelectric applications-from chemical reactions in CaO/Co3O4 multilayers. We show that CaO conversion to Ca(OH)(2) and the cobalt oxide stoichiometry are key determinants of nanoporosity. Adjusting the unreacted CaO fraction alters the nanopore size and fraction and the thermoelectric properties of Ca3Co4O9. The preferred orientation of Ca3Co4O9 is underpinned by the texture of the reactant multilayers and reactant-product crystallographic relationships and density difference. Oriented pore formation is attributed to basal plane removal driven by local densification of textured Ca3Co4O9 nuclei through growth and impingement. These findings point to possibilities for controllably engineering nanoporosity and properties in a variety of inorganic materials with laminated crystal structures. Funding Agencies|Knut and Alice Wallenberg Foundation through the Wallenberg Academy Fellows program [KAW 2020.0196]; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University [2009 00971]; Swedish Energy AgencySwedish Energy AgencyMaterials & Energy Research Center (MERC) [46519-1]; China Scholarship CouncilChina Scholarship Council

We prepared heterogeneous alumina-silicate glasses by consolidating nanoparticles using molecular dynamics simulations. Consolidated glasses from either low alumina content alumina-silicate glasses or high alumina content alumina-silicate glasses show significantly improved ductility around consolidation pressure of ~3 GPa. The introduced structural heterogeneities, namely over-coordinated network formers and their neighboring oxygen atoms, are identified as plasticity carriers due to their high rearrangement propensity. In addition, consolidated oxide glass from both 23.4Al2O376.6SiO2 and 73.1Al2O326.9SiO2 nanoparticles show improved flow strength (up to 1 GPa) due to the introduction of chemical heterogeneities. Last but not least, apparent hardening behavior appears upon cold work in consolidated glasses, with an increase of yield strength from ~3.3 GPa to ~6.4 GPa. This method is a big advancement toward ultra-strong and ultra-tough glasses by breaking the structure, composition and size limitations in traditional melt-quench process.

A new strategy for preparing amphibious ZnO quantum dots (QDs) with blue fluorescence within hyper-branched poly(ethylenimine)s (HPEI) was proposed in this paper. By changing [Zn2+]/[OH−] molar ratio and heating time, ZnO QDs with a quantum yields (QY) of 30% in ethanol were obtained. Benefiting from the amphibious property of HPEI, the ZnO/HPEI nanocomposites in ethanol could be dissolved in chloroform and water, acquiring a QY of 53%, chloroform and 11% in water. By this strategy, the ZnO/HPEI nano-composites could be applied in not only in optoelectronics, but also biomedical fields (such as bio-imaging and gene transfection). The bio-imaging application of water-soluble ZnO/HPEI nanocomposites was investigated and it was found that they could easily be endocytosed by the COS-7 cells, without transfection reagent, and they exhibited excellent biological imaging behavior.

To exploit a green way to produce polymer nanoparticles using biodegradable and renewable macromolecules instead of petroleum-based ones, we initiated a novel and facile method to synthesize lignin nanoparticles (LNPs). The LNPs, having a hydrodynamic diameter ranging from ca. 80 to 230 nm, were formed by self-assembly in a recyclable and non-toxic aqueous sodium p-toluenesulfonate (pTsONa) solution at room temperature, with a lowest concentration of up to 48 g/L. We eliminated the unfavorable factors of restricted processing pH and lignin species by taking advantage of the hydrotropic chemistry and the synergistic dissociation of the entrapped pTsONa and intrinsic phenolic hydroxyl and carboxylic acid moieties of the LNPs. Because of the hydrotropic system, various water-soluble or water-insoluble drugs can be dissolved and encapsulated in the LNPs with an encapsulation efficiency of up to 90%. The drug-encapsulated LNPs also showed great properties, with sustained drug-releasing capability and biocompatibility. Furthermore, the unloaded drugs and free pTsONa could be easily recycled for multiple use, thereby achieving environmental sustainability. This synthesis approach with broad processing window could realize the industrial scale-up production of LNPs and have wide potential applications, including but not limited to versatile drug/bioactive macromolecule loading in the biomedical field.

A new strategy for nanocrystal encapsulation, release and application based on pH-sensitive covalent dynamic hyperbranched polymers is described. The covalent dynamic hyperbranched polymers, with multi-arm hydrophobic chains and a hydrophilic hyperbranched poly(amidoamine) (HPAMAM) core connected with pH-sensitive imine bonds (HPAMAM&ndash, DA), could encapsulate CdTe quantum dots (QDs) and Au nanoparticles (NPs). Benefiting from its pH response property, CdTe QDs and Au NPs encapsulated by HPAMAM&ndash, DA could be released to aqueous phase after imine hydrolysis. The released CdTe/HPAMAM and Au/HPAMAM nanocomposites exhibited excellent biological imaging behavior and high catalytic activities on p-nitrophenol hydrogenation, respectively.

Strong interactions between loading drugs and nanocarriers contribute greatly to the high loading capacity while bringing about the problems on effective drug release. To solve this dilemma, we develop a density functional theory (DFT)-guided drug loading strategy to construct a dismountable nanoplatform for sensitized tumor-homing thermotherapy. DFT, a kind of computational method, is used to screen out a heat shock protein90 (HSP90) inhibitor, geldanamycin (GDM), that highly matched the structure of nanocarriers, thus providing a high drug loading efficiency (~ 42%). Of special note, GDM could be effectively released inside tumor cells because the isoelectric points of cancer cell membrane (CCM) and polydopamine (PDA) are both around pH 4.0 ~ 5.0, which could exactly match with the acidic environment of endo/lysosome. The CCM envelope enables self-targeting of PDA/GDM@CCM to the source cancer cells and homologous tumors while effectively inhibiting recognition and clearance by macrophages. Efficient photothermal ablation is attributed to the efficient suppression of tumor heat resistance by GDM and precise selection of the best matched tumor type by using The Cancer Genome Atlas (TCGA). This DFT-guided drug loading strategy points out a new avenue for optimization of drug-loading into nanocarriers, and ultimately contributes to the high drug availability and excellent curative effect.

Al2O3–SiO2 binary glasses with structural and chemical heterogeneities were prepared by consolidating glassy nanoparticles with different compositions using classical molecular dynamics simulations. Consolidated glasses show both excellent ductility and enhanced flow strength. It was found that the structural heterogeneities such as over-coordinated network formers and neighboring oxygen induced during consolidation serve as plasticity carriers to increase the ductility. On the other hand, the enhanced yield strength in consolidated glasses is due to the chemical heterogeneity inherited from the starting glassy nanoparticles, which does not compromise the ductility. Furthermore, apparent work hardening behavior appears upon cold work in the consolidated glasses, with an increase in yield strength from ~3.3 to ~6.4 GPa after 40% cold work. Consolidation with glassy nanoparticles could be a viable way to synthesize strong, damage resistant and transparent oxide glasses that cannot be obtained through the traditional melt-quench process.

A new strategy for the construction, release and cellular imaging application of triethylamine-responsive fluorescent quantum dots (QDs) based on supramolecular self-assembly has been described. The supramolecular self-assembly (HPEI/SA), which was constructed through the electrostatic interactions between terminal amine groups of hyperbranched polyethylenimines (HPEI) and carboxylic acid groups of stearic acid (SA), first captured aqueous Zn2+ ions into the hydrophilic dendritic core and subsequently encapsulated QDs/S2- by the complexation interactions and reactions between Zn2+ and S2- on QDs. Due to the pH-responsive property of the HPEI/SA supramolecular self-assembly, the fluorescence of encapsulated QDs is sensitive to the triethylamine/SA mole ratio, and the encapsulated QDs can be released to the aqueous phase by cleaving HPEI/SA. The resulting fluorescent QDs/HPEI nanocomposites show promising prospects in bioimaging.

The brittleness of oxide glasses has dramatically restricted their practical applications as structural materials despite very high theoretical strength. Herein, using molecular dynamics simulations, we show that silica glass prepared by consolidating glassy nanoparticles exhibit remarkable tensile ductility. Because of dangling bonds at surfaces and high contact stresses, the pressure applied for consolidating glassy nanoparticles to achieve ductility is significantly lower than that required to toughen bulk glass via permanent densification. We have identified 5-fold silicon, with a higher propensity to carry out local shear deformation than 4-fold silicon, as the structural origin for the observed tensile ductility. Interestingly, the work hardening effect has been, for the first time, observed in thus-prepared silica glass, with its strength increasing from 4 GPa to ∼7 GPa upon cold work. This is due to stress-assisted relaxation of 5-fold silicon to 4-fold during cold work, analogous to transformation hardening.

Background Ara h 1 is a major food allergen in peanuts. Recently, many studies have revealed that the Maillard reaction (MR) affects the allergenicity of food proteins. Results To investigate the influence of the MR on the allergenicity of Ara h 1, R-Ara h 1 was processed with glucose in dry heating conditions for different periods. The extent of the MR was assessed by four methods. The changes in secondary and tertiary structures were characterized through spectroscopy assays. Advanced glycation end products (AGE) structures were identified by protein sample dry heating for 60 min, indicating the formation of AGE-Ara h 1. Simulated gastric fluid (SGF) digestion analysis showed that AGE-Ara h 1 has higher resistance to peptic digestion than R-Ara h 1. The BALB/c mouse model was also utilized to explore the effect of the MR on the allergenicity of Ara h 1, and the results showed that the Th2-type cytokines, antibodies, and histamine content increased, and there was a greater degree of degranulation of rat basophilic leukemia (RBL) cells in the AGE-Ara h 1 group compared with the R-Ara h 1 group. Conclusion During the process of dry heating, proteins participated in the MR with changes in secondary and tertiary structures. The condition applying a temperature of 100 °C for 60 min caused the formation of AGE-Ara h 1. Simulated gastric fluid digestion analysis showed that AGE-Ara h 1 had a greater resistance to peptic digestion than R-Ara h 1. The BALB/c mouse model showed that AGE-Ara h 1 had more allergenicity, indicating that the MR could enhance the allergenicity of Ara h 1. © 2020 Society of Chemical Industry.

Experimental studies have shown that glass systems with high boron content exhibit superior crack resistance under sharp contact loading. However, the underlying mechanism is still not fully understood. In this context, we carried out classical molecular dynamics simulations on sodium aluminosilicate and sodium aluminoborate systems to investigate the effect of boron on the response of glass to nanoindentation. A rigid V-shaped indenter is used to indent the glass sample with a fixed loading rate, during which the indenter interacts with the glass via a repulsive force field. The indenter angle and tip radius are varied to study the effect of indenter sharpness, as what has been done in experiments. These simulated nanoindentation tests reveal how the stress/strain field and the glass structure evolve with deformation underneath the indenter. It was found that a large number of boron atoms in the plastic zone change from three- to fourfold coordination during the loading process, and most of them revert back to the threefold coordination state during the unloading process. Our study shows that this “reversible” boron coordination change plays a critical role in increasing the damage resistance of glass.

Leonurus japonics Houtt. (Lamiaceae) is an annual or biennial herbaceous plant widely distributed and cultivated in China. The dried herb is used in TCM for the treatment of various diseases, especially menstrual disturbances, dysmenorrhea, and amenorrhea. Recently, phytochemical studies on this plant have been reported. Our previous investigation on two plants of the family Lamiaceae resulted in the isolation of a number of new labdane-type diterpenes. In our continuing research on secondary metabolites from L. japonicus, five diterpenoids including two new and three known ones were isolated and identified. The new compounds (Fig. 1) were elucidated as 1-((2S)-2-(3-(furan-3yl)propanoyl)-2,6,6-trimethylcyclohexyl)-2-hydroxybutan1-one (1), and 1-((1S,3R,3aS)-3-(2-(furan-3-yl)ethyl)-3methoxy-3a,7,7-trimethyloctahydroisobenzo furan-1-yl)propan-1-one (2). The known compounds were identified as seco-labdane (3), 6b-hydroxy-15,16-epoxylabda-8,13(16), 14-trien-7-one (4), and leojaponin (5). The ethanol extract of the powdered herb of L. japonicus was first separated by macroporious resin (D101) and then repeatedly separated by silica gel column chromatography, Sephadex LH-20, and preparative HPLC to give compounds 1–5. Compound 1 was obtained as a colorless oil, [α] D + 36.3 (c 0.1, MeOH), and was established to have a molecular formula of C20H30O4 by HRESIMS ([M + H] + m/z 335.2178; calcd. 335.2222). The H, C NMR and DEPT data (Table 1) exhibited resonances for three tertiary methyl groups (δH 0.76, 0.87, 0.90; δC 29.3, 29.5, 25.6, respectively), two carbonyl groups (δC 215.7, 213.2), a monosubstituted furan (δH 7.33, 7.23, 6.25; δC 110.9, 123.8, 139.2, 142.8), five methylenes (δC 37.2, 34.2, 31.4, 26.7, 19.5, 19.1), two methines including one oxygenated (δH 3.58 s, 4.03 d J = 8.0 Hz; δC 53.8, 80.6), and two quaternary carbons (δC 34.5, 49.9). These spectroscopic data indicated 1 to be an 8,9-seco-labdane diterpenoid with a hydroxyl group (δH 3.44 s). The H NMR data of 1 were similar to those of the lagopsin F and 8,9-secohispanolone except for the absence of the resonances of an acetoxy group and a replacement of carbonyl with a hydroxyl group in lagopsin F. However, carefully analysis of the H-H COSY spectra, the cross peak between the two protons of methines (H-5 and H-7) was not observed, and correlation from H-7 to H2-8 (δH 1.30 m) was obviously detected. It suggested that the hydroxyl group was connected to C-7, rather than C-6 as lagopsin F. The proposed structure of 1 was further confirmed by the HMBC correlations between H3-20 and C-1/C-5/C-9/C-10; H3-18 and C-19/C4/C-5; H3-17 and C-7/C-8; H-16 and C-13/C-14/C-15; H15 and C-13/C-14/C-16; H-14 and C-13/C-15/C-16; H2-12 and C-9/C-11/C-13/C-14/C-16; H2-11 and C-9/C-12/C-13; H-8 and C-7/C-17; H-5 and C-1/C-3/C-4/ C-6/C-7/C-9/C10, and H-7 and C-5/C-6/C-8/C-17 (Fig. 2). However, the C-7 relative configuration could not be assigned. Therefore, the structure of 1 was identified as 1-((2S)-2-(3-(furan-3yl)propanoyl)-2,6,6-trimethylcyclo-hexyl)-2-hydroxybutan -1-one, and named secoleojaponol. Compound 1 has not been previously reported. Compound 2, a colorless oil, [α] D 3.6 (c 0.1, MeOH) was shown to have a formula of C21H32O4 by HRESIMS ([M + H] m/z 349.2020; calcd. 349.2015). The NMR data (Table 1) showed that compound 2 has three tertiary methyl groups (δH 0.75, 1.04, 1.12; δC 33.6, 22.2, 17.0, respectively) and a methoxy group (δH 3.35, s; δC 48.8) a propanoyl group [δH 1.08 (3H, t, J = 8.0 Hz), 2.65 (2H, q, J = 8.0 Hz ); δC 7.6

The recent interest and excitement in graphene has also opened up a pandora's box of other two-dimensional (2D) materials and material combinations which are now beginning to come to the fore. One family of these emerging 2D materials is transition metal dichalcogenides (TMDs). So far there is very limited understanding on the wetting behavior of "monolayer" TMD materials. In this study, we synthesized large-area, continuous monolayer tungsten disulfide (WS2) and molybdenum disulfide (MoS2) films on SiO2/Si substrates by the thermal reduction and sulfurization of WO3 and MO3 thin films. The monolayer TMD films displayed an advancing water contact angle of ∼83° as compared to ∼90° for the bulk material. We also prepared bilayer and trilayer WS2 films and studied the transition of the water contact angle with increasing number of layers. The advancing water contact angle increased to ∼85° for the bilayer and then to ∼90° for the trilayer film. Beyond three layers, there was no significant change in the measured water contact angle. This type of wetting transition indicates that water interacts to some extent with the underlying silica substrate through the monolayer TMD sheet. The experimentally observed wetting transition with numbers of TMD layers lies in-between the predictions of one continuum model that considers only van der Waals attractions and another model that considers only dipole-dipole interactions. We also explored wetting as a function of aging. A clean single-layer WS2 film (without airborne contaminants) was shown to be strongly hydrophilic with an advancing water contact angle of ∼70°. However, over time, the sample ages as hydrocarbons and water present in air adsorb onto the clean WS2 sheet. After ∼7 days, the aging process is completed and the advancing water contact angle of the aged single-layer WS2 film stabilizes at ∼83°. These results suggest that clean (i.e., nonaged) monolayer TMDs are hydrophilic materials. We further show that substitution of sulfur atoms by oxygen in the lattice of aged monolayer WS2 and MoS2 films can be used to generate well-defined 'hydrophobic-hydrophilic' patterns that preferentially accumulate and create microdrop arrays on the surface during water condensation and evaporation experiments.

Leojaponin (2), a labdane diterpene, was isolated from the EtOH extract of the herb of Leonurus japonicus together with a new halimane diterpene named isoleojaponin (1). Isoleojaponin has a new diterpene skeleton with a unique cross-conjugated α,β-unsaturated ketone system, Their structures were elucidated by physical and spectroscopic analysis, and the relative configuration of the chiral C-9 carbon was determined by a computational method, and analysis of its possible biogenesis pathways.

A novel enzyme-free hydrogen peroxide (H2O2) sensor was fabricated by coating graphene oxide (GO), branched polyethylenimine (PEI) and Pd particles in sequence on the surface of glassy carbon (GC) electrode (Pd-PEI/GO/GC). A layer-by-layer method was used, which involved π–π interactions, covalent bonding through 1-ethyl-3-[3-dimethylaminopropyl]carbodiimide/N-hydroxysulfosuccinimide (EDC/NHSS) chemistry, electrostatic adsorption and electroreduction. The Pd-PEI/GO/GC electrode exhibited high electrocatalytic activity, a low detection limit, and good stability for the detection of H2O2. The sensor’s practical application was tested via determination of H2O2 in real water samples.

With a hyperbranched poly(amidoamine) core and many water-soluble poly(ethylene glycol) monomethyl ether arms connected by pH-sensitive acylhydrazone bonds, multiarm hyperbranched polymer was used as nanoreactor and reductant to prepare metal nanoparticles endowed with intelligence and biocompatibility. The multiarm hyperbranched polymer encapsulated nanoparticles (NPs) showed excellent catalytic activity for hydrogenation, thus an excellent catalyst system for hydrogenation was established. The rate constants could reach as high as 3.48 L·s−1·m−2, which can be attributed to the lack of surface passivation afforded by the multiarm hyperbranched polymer.

A new strategy for the preparation of Fe3O4 nanocrystals (NCs) and FePt bimetal NCs with amphiphilic hyperbranched polymers as unimolecular nanoreactors has been described. The amphiphilic hyperbranched polymers were synthesized by grafting methyl acrylate to hyperbranched poly(ethylenimine)s (HPEI) with the help of Michael addition reaction. The hydrophilic HPEI core was used to stabilize the magnetic NCs, whereas the hydrophobic methyl ester terminals can prevent the aggregation of polymers and NCs, thus magnetic NCs with a narrow size distribution were prepared. The resulting Fe3O4 NC/amphiphilic hyperbranched polymer nanocomposites also showed slightly better magnetofection property than HPEI transfection and their luciferase expression level in maximum was 1.3-fold greater than that for HPEI transfection. POLYM. COMPOS., 00:000–000, 2014. V C 2014 Society of Plastics Engineers

Branched polyethylenimine (PEI) was covalently linked to graphene oxide (GO) pre-modified on glassy carbon (GC) electrode (PEI/GO/GC) via an amide bond with 1-ethyl-3-[3-dimethylaminopropyl]carbodiimide/N-hydroxysulfosuccinimide (EDC/NHS) chemistry, and gold nanoparticles was then assembled on the surface of the PEI/GO/GC electrode (Au-PEI/GO/GC) by the electro-reduction of absorbed AuCl4− through electrostatic interaction. The Au-PEI/GO/GC electrode exhibited high electrocatalytic activity toward nitrite oxidation and hydrogen peroxide (H2O2) reduction. The analytical performances of the Au-PEI/GO/GC electrode demonstrated low detection limit, wider linear range, and good stability for the determination of nitrite and H2O2, which make it a promising candidate for amperometric nitrite or enzymeless H2O2 sensor.

A novel poly(methacrylic acid) (PMAA) microcarriers coated with nanolayered chitosan(Cs) and carboxyl modified multi-walled carbon nanotubes (MWCNTs-COOH) via self-assembly method, has been successfully prepared for better loading and sustained release of gatifloxacin (GFLX). Due to the multi-loading and gradient release properties, PMAA/Cs/CNTs could adsorb a great amount of drug (84.89±9.63 μg mg −1 ), and 64.74±2.78% of its loading could slowly release in 24 h, which is important to delivery GFLX effectively and to reduce the risk of side effects.

Sepsis is a major cause of morbidity and mortality in critically ill patients. MD-2 is a 25-kDa lipopolysaccharide (LPS)-binding protein that forms a heterodimer with TLR42, but its regulation in sepsis is not clear. This study aims to investigate the molecular mechanism of regulation of MD-2. Inflammation cytokines in monocytes were analyzed by real-time RT-PCR and ELISA, and it was found that IL-10 was elevated significantly in the monocytes with LPS treatment. And then, when the cells were treated with IL-10, STAT1 was activated in the monocytes using Western blotting. It was also found that STAT1 could enhance MD-2 expression on transcriptional and posttranscriptional levels. Finally, miR-30a was predicted to the molecule that may regulate STAT1 expression. It was verified that STAT1 was a new target gene of miR-30a. miR-30a could inhibit IL-10-induced cytokine release by targeting STAT1-MD-2 in monocytes. In conclusion, this study for the first time demonstrated that miR-30a inhibits MD-2 expression by targeting of STAT1 in human monocytes.

In this paper we report a simple method that enables the easy fabrication of ultrathin porous anodic aluminum oxide (AAO) membranes from two-step anodization in oxalic acid solution. ZnO nanotubes have been synthesized by injecting sol–gel into the pores of the ultrathin AAO membrane. The structures and morphologies of the ultrathin AAO membrane and ZnO nanotubes were characterized by X-ray diffraction, scanning electron microscopy and transmission electron microscope. The thickness of the as-prepared AAO membranes is about 1 μm with highly ordered pores inside, and the ZnO nanotubes are straight with uniform thickness along the length and with diameter equal to those of nanopores.

a b s t r a c t N-doped TiO2 nanooctahedra, nanoparticles and nanospheres were successfully synthesized through nitrification of the corresponding TiO2 nanostructures in the presence of ammonia gas at 700 ◦ C for 30 min. The crystal phase and compositions of N-doped TiO2 samples were confirmed by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS), respectively. The product morphology was characterized with scanning microscopy (SEM) and transmission electron microscopy (TEM). UV-vis absorption results show that all the as-synthesized N-doped TiO2 samples present red-shift absorption up to ∼410 nm, which can be ascribed to the addition energy level between TiO2 valence and conducion band. Surface areas of all samples were measured through nitrogen absorption-desorption isothermal. In order to eval- uate the photocatalytic activity of N-doped TiO2 samples, photodecomposition for methyl orange (MO) was performed under UV-vis light irradiation for 30 min, indicating that N-doped TiO2 nanooctahedra with the exposed {1 0 1} crystallized surfaces show good photocatalytic behavior in comparison with other samples.

We presented a molecular-designed multi-walled carbon nanotube (MWCNT) layer-by-layer (LbL) multilayer on poly- l -lactic acid (PLLA) electrospun fibers for engineering cell/CNT interfaces. A stable, positively charged monolayer was created on the fiber surface by the aminolysis reaction of poly(ethylene imine) (PEI) with PLLA, followed by alternate deposition in negatively charged MWCNT and positively charged chitosan (CS). Thermogravimetric analysis indicated a sustained growth of the MWCNT during the self-assembly process. The interactions between MWCNT and polycation crucially affected the specific structure and properties of the MWCNT multilayer. MWCNT/PEI electrostatic interactions reduced the gap between MWCNTs and improved the π → π∗ transitions. However, the CS chains tended to be more serpentine than the chains of PEI molecules, which might have hindered the π → π∗ transitions. On the other hand, the electrostatic interactions might have enhanced the disorder grade of the MWCNT structure, as indicated by Raman analysis. The scaffolds maintained their fibrous and porous structure after MWCNT multilayer modification and supported fibroblast growth. The MWCNT multilayer induced cell migration toward the interior of the scaffolds. Therefore, we created a simple yet efficient method of building a CNT multilayer on three-dimensional (3D) fibrous scaffolds for enhancing cell-matrix interactions.

Hyperbranched poly(amidoamine)s with methyl ester terminals (HPAMAM-COOCH3) were used as nanoreactors and reductants to prepare gold or silver nanoparticles (Au NPs or Ag NPs). HPAMAM-COOCH3 could bind AuCl4 − (or Ag+) and then reduce AuCl4 − (or Ag+) into Au NPs (or Ag NPs) through their internal amines, while the external methyl ester groups prevented the aggregation of polymers. The formation of Au NPs or Ag NPs was verified using transmission electron microscopy (TEM), ultraviolet-visible spectroscopy (UV-Vis), X-Ray powder diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), and thermogravimetric analysis (TGA), confirming the formation of Au NPs or Ag NPs with small particle size and low size distribution.POLYM. COMPOS., 2013. © 2013 Society of Plastics Engineers

A novel star-shaped polymer, porphyrin-poly(L-lysine) dendrons (PP-PLLD), is synthesized by the click reaction between azido-modified porphyrin and propargyl focal point poly(L-lysine) dendrons. Its chemical structure is characterized by (1) H nuclear magnetic resonance, Fourier transform infrared spectroscopy, and gel permeation chromatography (GPC) is analyses etc. Due to its amphiphilic property, the obtained PP-PLLD has a low critical micelle concentration in an aqueous solution, and can load doxorubicin (DOX) with a loading amount of 64 μg mg(-1) . By in vitro toxicity assay, PP-PLLD has no dark cytotoxicity but has significant phototoxicity. Moreover, DOX-loaded PP-PLLD shows a higher cytotoxicity under the light condition than PP-PLLD or DOX alone, suggesting PP-PLLD has a potential application in combined photodynamic therapy and chemotherapy.

We describe an electrostatic droplet generation method to prepare a novel carboxymethyl chitosan−graphene oxide hybrid particles for delivery purpose. Under an adjustable electrostatic field, graphene oxide and carboxymethyl chitosan mixed solution was sprayed as uniform micro-droplets, which were solidified as particles in CaCl2 solution. Such hybrid particles are wished to have excellent stability in saline solution, and better delivery properties than pristine carboxymethyl chitosan particles. The effects of micro-droplets generation conditions on particles formation were systematically investigated. At conditions of 40 mg/ml of carboxymethyl chitosan, 2 mg/ml of graphene oxide, 3 ml/h of feed speed, electrostatic field parameters was 9 kV and 20 cm, uniformly sized carboxymethyl chitosan–graphene oxide particles in the diameter range of 250–300 μm was successfully prepared. In NaCl saline, these particles could maintain stable for at least a week, while pristine carboxymethyl chitosan particles quickly collapsed within an hour. The results of loading experiments showed that carboxymethyl chitosan–graphene oxide particles could effectively adsorb gatifloxacin, ofloxacin, bovine serum albumin, lysozyme, doxorubicin hydrochloride. And gatifloxacin was chosen as a model drug to study the exact effect of graphene oxide content on the loading and release properties. In 40:2 group, the highest loading capacity of 0.45 ± 0.19 mg/mg was achieved, and also a good sustained release was available. Above all, we believed that carboxymethyl chitosan–graphene oxide particles as a versatile carrier, has great potential in Medicine and Pharmacy.

The architecture of conjugated polymers has an important influence on their optical and electrical properties. In this study, the effect of branching architecture on the optical properties of polyazomethines (PAs) was investigated. Linear and branched PAs with degree of branching (DB) ranging from 0 to 0.52 were successfully synthesized through homogeneous condensation by changing the feeding ratios of diamine, tetramine and dialdehyde. All PAs showed good thermal stability, and their decomposition temperature was over 380 °C. Both UV-Vis absorption and fluorescence emission demonstrated that the optical properties of PAs were closely related to the DB. With the increase of DB, an obvious redshift was found in UV-Vis absorption spectra, and the fluorescence maximum emission intensity (FMEI) and relative fluorescence quantum efficiency (RFQE) initially increased to a maximum and then gradually diminished to almost zero. These phenomena could be attributed to the antagonistic effect between the auxochromic effect of amino groups and the intra- and inter-molecular interactions. To confirm this mechanism, the intra- and inter-molecular interactions were purposely broken by adding trifluoroacetic acid (TFA) and SnCl2, which resulted in an increase in FMEI. Therefore, the optical properties of conjugated polymers can be readily adjusted by changing the DB of polymers.

A new strategy for the size-controlled preparation of magnetic iron oxide nanocrystals (NCs) within hyperbranched poly(ethylenimine)s (HPEIs) has been described. HPEI was not only utilized as the nanoreactors and stabilizers to prepare size-controlled magnetic NCs, but also skillfully used as a base supplier to avoid introducing alkali hydroxide or ammonia. By changing the weight ratio of FeSO4·7H2O to HPEI, magnetic iron oxide NCs with various sizes were obtained. Owing to the efficient gene transfection properties of HPEI, the resulting iron oxide/HPEI nanocomposites were used as magnetic nonviral gene vectors for magnetofection and showed to be good gene vectors. It was found that the size of magnetic iron oxide had a significant effect on the magnetofection properties while a pure HPEI transfection enhancer was not introduced. When the mean size of magnetic iron oxide increased, the transfection efficiency was enhanced. With the addition of a pure HPEI transfection enhancer, the size of magnetic iron oxide showed a slight impact on the magnetofection properties. The luciferase expression levels mediated by iron oxide/HPEI nanocomposites with various iron oxide sizes in COS-7 cells under a magnetic gradient field were all more than 115 fold of that of standard HPEI transfection.

To explore the coordination possibilities of fluorene-based ligands, two manganese(II) complexes with the ligand 9,9-dibutyl-9H- fluorene-2,7-carboxylate (L) were synthesized and characterized: (Mn2(L)2(DMF)3)∞ (1) and (Mn2(L)2(DMF))∞ (2). X-ray single-crystal diffraction analyses show that complex 1 has a two-dimensional (2D) (4,4) structure, whereas complex 2 consits of a three-dimensional (3D)

Aluminum nitride (AlN) is a popular buffer layer and interlayer. The understanding of how AlN serves as a wetting and fracture-mitigating layer relies on molecular pictures of the AlN layer and the interfaces. However, molecular dynamics (MD) simulation studies on AIN system, particularly on its wurtzite phase, have been limited. This is because most existing interatomic force fields of AlN target the less common zinc blende phase. Here, we report a new Tersoff-based AlN force field for its wurtzite structure. This potential has been extensively tested in terms of lattice parameters, bulk modulus, cohesive energy, and heat capacity. In addition, thermal expansion coefficient (TEC) of wurtzite AIN, a key property to precisely model heterostructures, has been calculated using MD method. The value of 2.66 x 10 ―6 K ―1 calculated at 300 K for TEC is in excellent agreement with the reported experimental value.

Efficient intracellular translocation is achieved using an easily prepared hyperbranched polysulfonamine that remains negatively charged at physiological pH. Investigations on the cellular uptake mechanism and the subcellular distribution of PSA are reported. The in vitro cytotoxicity of PSA is found to be low. Using doxorubicin as a model drug, a PSA/drug complex is prepared by electrostatic interaction with a high drug payload that exhibits a controlled release in response to pH. Efficient intracellular drug delivery, strong growth inhibition of tumor cells, and low cytotoxicity to normal cells are observed. The results suggest a possible way to utilize anionic polymers for intracellular delivery of therapeutic moieties or drugs.

Chitosan acetate nano-fibers were fabricated via a solid–liquid phase separation technique. The chitosan acetate structure was influenced by phase separation temperature, chitosan concentration and acetic acid concentration. Uniform nano-fibrous chitosan acetate of 50–500 nm in diameter was engineered at 0.05% (w/v) chitosan and 0.025% (v/v) acetic acid in liquid nitrogen, as opposed to film-shape and micro-fibrous structure at −18 °C and −80 °C respectively. Decreasing the chitosan concentration led to the formation of nano-fibrous/floccules-like structure, while increasing the acetic acid concentration resulted in nano-/micro-fibrous structure instead. The chitosan acetate structure was closely related to the crystallinity varying with different phase separation conditions. Nano-fibrous chitosan acetate showed a medium crystallinity with a glass transition temperature of 155.1 °C and a heat capacity of 29.1 J/g comparing with nano-fibrous/floccules-like and nano-/micro-fibrous samples. The chitosan acetate crystal was also found changeable from form I to form II after solid–liquid phase separation in liquid nitrogen.

A new two-phase route was developed to prepare monodisperse cadmium sulfide (CdS) quantum dots (QDs) with a narrow size distribution. In a two-phase system, chloroform and water were used as separate solvents for palmitoyl chloride functionalized hyperbranched polyamidoamine (HPAMAM-PC) and cadmium acetate/sodium sulfide, respectively. The amphiphilic HPAMAM-PC, with a hydrophilic dendritic core and hydrophobic arms, formed stable unimolecular micelles in chloroform and was used to encapsulate aqueous Cd2+ ions. After the reaction with S2− ions from the aqueous phase, monodisperse and uniform-sized CdS QDs stabilized by HPAMAM-PC unimolecular micelles were obtained. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci 120:991–997, 2011

The present study describes a rapid and sensitive HPLC method for the quantification of huperzine A (HupA) in Huperzia Crispata (Huperziaceae). The sample extraction and preparation involved a simple, time-saving, single-solvent extraction, with each sample being analyzed within 12 min. The mobile phase was ammonium acetate (0.1 M, pH 6.0)methanol (64 + 36, v/v) at a flow rate of 1.0 mL/min. Detection was at 308 nm. The calibration curve was linear from 0.049 to 7.84 µg (R2 = 0.9997), with intraday and interday precision RSD of less than 2%. The extraction recovery rate was over 98.49%. Quantification of HupA was performed using this modified method, and the content of HupA was 1.86 times higher in the whole plant of H. crispata (218.17 ± 1.55 µg/g) than in that of H. serrata (117.03 ± 2.97 µg/g). In the whole plant of H. crispata, HupA mainly accumulated in the actively growing shoot tips, the apical bud, and the 10 youngest leaves, reaching 455.23 ± 2.97 µg/g. The content of HupA in the samples from sunshine-sheltered sites was 3.45 times higher than in that from sunshine-abundant sites. The satisfactory results indicate that this modified method can be applied in the quality control of large-scale Huperziaceae plant extracts and that changes should be made in the cultivation of H. crispata so as to maximize the production of HupA.

Aromatic compounds (ACs) in soil can induce competitive inhibition for soil NH3 oxidation, and nitrification inhibitors can be used to this end. A laboratory incubation experiment was performed with 12 nitroaromatic compounds (NACs), 15 amidoaromatic compounds (AACs) and 20 hydroxyaromatic compounds (HACs) to assess the inhibitory effects of ACs on soil nitrification. Based on these results, the critical and optimal concentrations of ACs were determined for better inhibitory effects. Most of the test ACs were able to inhibit soil nitrification; the effectiveness differed with soil type. Among the ACs, the NACs with m-nitryl, amino or hydroxyl and the AACs with a nitro group or a chlorine atom on aromatic ring or with a p-hydroxyl were more effective. 3-nitroaniline, 4-aminophenol and 3-nitrophenol showed the greatest potential as nitrification inhibitors. The critical concentration of these compounds in brown soil and cinnamon soil was found to be 0.5 mg kg−1 soil. Due to the toxicity, carcinogenicity and mutagenicity of ACs, further toxicological and ecotoxicological research is necessary before ACs are used as nitrification inhibitors in agricultural and horticultural practices.

A simple approach to tune the optical properties of the hyperbranched conjugated polymers by only adjusting the terminal-backbone interactions has been reported in this article. Hyperbranched conjugated polyazomethines have been successfully prepared by the reaction of tetramine and dialdehyde. Not only varying the monomer feed ratio to change the quantity of terminal amino groups, but also adopting protonation or complexion with proper dopants (SnCl 2 and β-cyclodextrin), can alter the interactions between amino terminals and imine bonds in the backbone. Correspondingly, the optical properties of the resulting hyperbranched polymers are controlled.

Molecular dynamics simulations are used to model the shock loading of an interface with various degrees of nanometer scale faceting between an inert binder and an energetic crystal. The facets create regions of local compression that induce exothermic reaction that leads to local hotspots and an increased shock sensitivity to detonation. Two mechanisms for compression and hotspot formation are identified that depend on the shock impedance mismatch between the binder and energetic crystal, namely shock focusing and local compression of the facets. These results provide a possible explanation for why spherical RDX crystals in cast polymer-bonded explosives appear less shock sensitive than RDX with more faceted morphologies.

A simple two-step strategy using phospholipid (PPL) to functionalize core/shell CdSe/ZnS quantum dots (QDs) has been described. The experimental data show that the use of S–H terminated PPL results not only in the high colloidal stability of core/shell CdSe/ZnS QDs in the aqueous phase, but also in the significant enhancement of photoluminescence. The degree of the enhancement is a function of the PPL–CdSe/ZnS QDs sample concentration. These results might be promising for future biological platform in new devices ranging from photovoltaic cells to biosensors and other devices.