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The Au-MoS 2 nanocomposites (NCPs) exhibit excellent visible-light photocatalytic activity and potential applications in the photocatalytic degradation of organic dyes. In this study, an Au-MoS 2 heterojunction structure with Au nanoparticles (NPs) deposited on MoS 2 nanosheets was synthesized via the pulsed laser-induced photolysis method. The influence of Au content on the photocatalytic performance was systematically investigated, and the working mechanism under visible light excitation was elucidated. The optimal Au-MoS 2 NCPs exhibited efficient degradation of methylene blue (MB) dye, mainly attributed to the plasmon resonance effect of Au NPs which facilitated the visible light harvesting and hot electron injection. The Au/MoS 2 interface promoted the separation and transfer of photogenerated charge carriers. The electrostatic adsorption between positively charged MB molecules and the negatively charged MoS 2 surface favored the affinity toward active sites. Furthermore, the photogenerated electrons and holes participated in generating reactive oxygen species such as superoxide and hydroxyl radicals, which initiated the oxidative degradation of MB. The PLIP-introduced Au NPs not only endowed the material with excellent visible light responsivity but also possibly modulated the electronic structure and photocatalytic active sites of MoS 2 through an intrinsic effect, providing new insights for further enhancing the photocatalytic performance of Au-MoS 2 NCPs., Competing Interests: The authors declare no competing financial interest., (© 2024 The Authors. Published by American Chemical Society.)

We report a step-economic strategy for the direct synthesis of spiro polycyclic N-heterocycles and indolecarbazole-fused naphthoquinones by merging oxidative coupling and cascade palladium-catalyzed intramolecular oxidative cyclization. In the protocol, bi-indolylnaphthoquinones were first synthesized by oxidative coupling of indoles and naphthoquinones. Subsequent cascade palladium-catalyzed intramolecular oxidative cyclization of bi-indolylnaphthoquinones gave spiro polycyclic N-heterocycles and indolecarbazoles. The intramolecular oxidative cyclization approach could also be realized by the presence or absence of iron catalysts under standard conditions. This protocol is featured with moderate to excellent yields, a wide substrate scope, and divergent structures of products.

The extracellular matrix (ECM) is the fundamental acellular element of human tissues, providing their mechanical structure while delivering biomechanical and biochemical signals to cells. Three-dimensional (3D) tissue models commonly use hydrogels to recreate the ECM in vitro and support the growth of cells as organoids and spheroids. Collagen-nanocellulose (COL-NC) hydrogels rely on the blending of both polymers to design matrices with tailorable physical properties. Despite the promising application of these biomaterials in 3D tissue models, the architecture and network organization of COL-NC remain unclear. Here, we investigate the structural effects of incorporating NC fibers into COL hydrogels by small-angle neutron scattering (SANS) and ultra-SANS (USANS). The critical hierarchical structure parameters of fiber dimensions, interfiber distance, and coassembled open structures of NC and COL in the absence and presence of cells were determined. We found that NC expanded and increased the homogeneity in the COL network without affecting the inherent fiber properties of both polymers. Cells cultured as spheroids in COL-NC remodeled the hydrogel network without a significant impact on its architecture. Our study reveals the polymer organization of COL-NC hydrogels and demonstrates SANS and USANS as exceptional techniques to reveal nano- and micron-scale details on polymer organization, which leads to a better understanding of the structural properties of hydrogels to engineer novel ECMs.

Simulating native mucus with model systems such as gels made from reconstituted mucin or commercially available polymers presents experimental advantages including greater sample availability and reduced inter- and intradonor heterogeneity. Understanding whether these gels reproduce the complex physical and biochemical properties of native mucus at multiple length scales is critical to building relevant experimental models, but few systematic comparisons have been reported. Here, we compared bulk mechanical properties, microstructure, and biochemical responses of mucus from different niches, reconstituted mucin gels (with similar pH and polymer concentrations as native tissues), and commonly used commercially available polymers. To evaluate gel properties across these length scales, we used small-amplitude oscillatory shear, single-particle tracking, and microaffinity chromatography with small analytes. With the exception of human saliva, the mechanical response of mucin gels was qualitatively similar to that of native mucus. The transport behavior of charged peptides through native mucus gels was qualitatively reproduced in gels composed of corresponding isolated mucins. Compared to native mucus, we observed substantial differences in the physicochemical properties of gels reconstituted from commercially available mucins and the substitute carboxymethylcellulose, which is currently used in artificial tear and saliva treatments. Our study highlights the importance of selecting a mucus model system guided by the length scale relevant to the scientific investigation or disease application.

Bearing triazine-centered linkers, three primitive metal-organic frameworks (MOFs) with a Zr 6 O 4 cluster have been prepared as Zr L1 (without any branch), Zr L2 (with -F), and Zr L3 (with -SCH 3 ). The electrocatalytic hydrogen evolution reaction (HER) by their pristine and transition metal-loaded (TM-loaded) forms was studied. It was found that the loading of TM ions could enhance the electrocatalytic power of these TM-loaded MOFs in HER, as reflected by their lower overpotentials and smaller Tafel slopes when compared with primitive MOFs. More importantly, the best electrocatalytic HER performance of Zr L3 -TM among all TM-loaded MOFs studied in this work highlights the effective housing of TM ions for unambiguous active sites through cooperative coordination by triazinic N and thioether pendants. This work proposes microenvironment regulation of MOFs as an effective strategy to enhance the electrocatalytic activity of MOF materials.

This study facilitates the synthesis of a graphitic carbon nitride/cesium tungsten oxide (g-C 3 N 4 @Cs 0.33 WO 3 ) heterojunction using a solvothermal method. The photocatalytic activities of the prepared samples were examined for the photodegradation of colorless antibiotics, namely tetracycline, enrofloxacin, and ciprofloxacin, as well as cationic and anionic dyes, such as methyl orange, rhodamine B, neutral red, and methylene blue, under full-spectrum solar light. We have purposely selected different kinds of wastewater pollutants of colorless antibiotics and cationic and anionic organic dyes to investigate the potential application of this heterojunction toward different groups of water pollutants. The results revealed that the g-C 3 N 4 @Cs 0.33 WO 3 heterojunction showed an outstanding photocatalytic activity toward all the pollutants with concentrations of 20 ppm each at pH 3 by photocatalytically removing 97% of tetracycline within 3 h, 98% of enrofloxacin within 2 h, 97% of ciprofloxacin within 2.25 h, 98% of methylene blue in 1 h, 99% of rhodamine B within 2 h, 99% of neutral red in 1.25 h, and 95% of methyl orange in 2 h. These findings indicate that the developed photocatalyst possesses excellent photocatalytic properties toward seven different water pollutants that make it a universal photocatalyst. The developed g-C 3 N 4 @Cs 0.33 WO 3 oxide heterojunction also presented a photocatalytic performance better than those of reported solar light active photocatalysts for photodegradation of rhodamine B and tetracycline. The efficient photocatalytic performance of the heterojunction can be ascribed to its extended light-absorbing ability, effective charge separation and fast charge transfer properties, and a high surface area. Moreover, an active species detection experiment also confirmed that superoxide radicals, hydroxyl radicals, and holes played significant roles in the photocatalysis of the organic dyes and tetracycline., Competing Interests: The authors declare no competing financial interest., (© 2022 The Authors. Published by American Chemical Society.)

Urolithin A (UA) is a metabolite produced in the gut following the consumption of ellagic acid (EA) rich foods. EA has shown anti-inflammatory, antioxidant, and anticancer properties. Because EA is poorly absorbed in the gastrointestinal tract, urolithins are considered to play a major role in bioactivity. Helicobacter pylori ( H. pylori ) infection is the most common chronic bacterial infection all over the world. It is potentially hazardous to humans because of its relationship to various gastrointestinal diseases. In this study, we investigated the effect of UA on inflammation by H. pylori . The results indicated that UA attenuated H. pylori -induced inflammation in vitro and in vivo. UA also reduced the secretion of H. pylori virulence factors and tissue injuries in mice. Furthermore, UA decreased the relative abundance of Helicobacteraceae in feces of H. pylori -infected mice. In summary, taking UA effectively inhibited the injury caused by H. pylori .

We have examined the spatial distributions of polymer chains in blend films of weakly segregated polystyrene -block- poly(methyl methacrylate) [P(S- b -MMA)] and deuterated polystyrene (dPS). By fine-tuning the composition (ϕ PS+dPS = 63.8 vol %) of the total PS/dPS component and annealing temperature (230 and 270 °C), P(S- b -MMA)/dPS blend films mainly form perforated layers with a parallel orientation (hereafter PLs // ). The distributions of dPS in PLs // were probed by grazing-incidence small-angle neutron scattering (GISANS) and time-of-flight neutron reflectivity (ToF-NR). GISANS and ToF-NR results offer evidence that dPS chains preferentially locate at the free surface and within the PS layers for blend films that were annealed at 230 °C. Upon annealing at 270 °C, dPS chains distribute within PS layers and perforated PMMA layers. Nevertheless, dPS chains still retain a surface preference for thin films. In contrast, such surface segregation of dPS chains is prohibited for thick films when annealed at 270 °C.

In order to investigate the energy transfer mechanism and the nonequilibrium effect during water evaporation in its own pure vapor at low pressures, a series of precise measurements are conducted to obtain the temperature profile near the liquid-vapor interface and the evaporation rates in an annular pool in a closed chamber. The results show that the interface temperature of the vapor side is higher than that of the liquid side when water evaporates in its own pure vapor at low pressures (ranging from 394 to 1467 Pa), the temperature discontinuity across the interface exists in all experimental conditions. The magnitude of the temperature discontinuity is strongly affected by the vapor pressure. A uniform temperature layer with a thickness of about 2 mm is found below the evaporating interface because of the coupling effect of evaporation cooling and thermocapillary convection. The energy required for evaporation is mainly transferred by thermocapillary convection in the uniform temperature layer. Furthermore, the numerical simulation results confirm that the evaporation flux near the cylinders is much larger than that at the middle region, which implies that most of the latent heat required for evaporation is transferred to the interface near the cylinders., Competing Interests: The authors declare no competing financial interest., (© 2021 The Authors. Published by American Chemical Society.)

Treatment of multidrug-resistant (MDR) bacterial infections increasingly relies on last-line antibiotics, such as polymyxins, with the urgent need for discovery of new antimicrobials. Nanotechnology-based antimicrobials have gained significant importance to prevent the catastrophic emergence of MDR over the past decade. In this study, phytantriol-based nanoparticles, named cubosomes, were prepared and examined in vitro by minimum inhibitory concentration (MIC) and time-kill assays against Gram-negative bacteria: Acinetobacter baumannii , Klebsiella pneumoniae , and Pseudomonas aeruginosa . Phytantriol-based cubosomes were highly bactericidal against polymyxin-resistant, lipopolysaccharide (LPS)-deficient A. baumannii strains. Small-angle neutron scattering (SANS) was employed to understand the structural changes in biomimetic membranes that replicate the composition of these LPS-deficient strains upon treatment with cubosomes. Additionally, to further understand the membrane-cubosome interface, neutron reflectivity (NR) was used to investigate the interaction of cubosomes with model bacterial membranes on a solid support. These results reveal that cubosomes might be a new strategy for combating LPS-deficient Gram-negative pathogens.

A metal-oxide material (indium zinc oxide [IZO]) device with near-infrared (NIR) laser annealing was demonstrated on both glass and bendable plastic substrates (polycarbonate, polyethylene, and polyethylene terephthalate). After only 60 s, the sheet resistance of IZO films annealed with a laser was comparable to that of thermal-annealed devices at temperatures in the range of 200-300 °C (1 h). XPS, ATR, and AFM were used to investigate the changes in the sheet resistance and correlate them to the composition and morphology of the thin film. Finally, the NIR-laser-annealed IZO films were demonstrated to be capable of detecting changes in humidity and serving as a highly sensitive gas sensor of hydrogen sulfide (in ppb concentration), with room-temperature operation on a bendable substrate.

Magnetic properties of fully oxygenated bare CuO nanoparticles have been investigated using magnetization, X-ray diffraction, neutron diffraction, and Raman scattering measurements. The Langevin field profile is clearly revealed in the isothermal magnetization of 8.8 nm CuO nanoparticle assembly even at 300 K, revealing a 172 times enhancement of the ferromagnetic responses over that of bulk CuO. Surface magnetization of 8.8 nm CuO reaches 18% of the core magnetization. The Cu spins in 8.8 nm CuO order below 400 K, which is 1.7 times higher than the 231 K observed in bulk CuO. A relatively simple magnetic structure that may be indexed using a modulation vector of (0.2, 0, 0.2) was found for the 8.8 nm CuO, but no magnetic incommensurability was observed in bulk CuO. The Cu spins in 8.8 nm CuO form spin density waves with length scales of 5 chemical unit cells long along the crystallographic a - and c -axis directions. Considerable amounts of electronic charge shift from around the Cu lattice sites toward the interconnecting regions of two neighboring Cu-Cu ions, resulting in a stronger ferromagnetic direct exchange interaction for the neighboring Cu spins in 8.8 nm CuO., Competing Interests: The authors declare no competing financial interest., (Copyright © 2020 American Chemical Society.)

Ultraviolet irradiation (UVI) of varied duration caused cross-linking and neutralization of polystyrene (PS) homopolymers of molar mass ( M n ) from 6 to 290 kg mol -1 on a silicon-oxide surface. An optimal neutral skin layer on the surface of the PS was obtained via brief UVI in air (UVIA), by which the PS had no preferential interaction with either block in the copolymer. UVI in an inert environment (gaseous dinitrogen) (UVIN) stabilized the PS layers via cross-linking and enabled the PS networks to have an effective adhesive contact with the underlying substrate. Thorough examination of domain orientations and spatial orders of a series of block copolymer, polystyrene- block -poly(methyl methacrylate) (PS- b -PMMA), thin films deposited on these UVI-treated PS support layers yielded clear evidence that a dense layer of neutralized PS chains was required for the perpendicular orientation of PS- b -PMMA nanodomains. In particular, in addition to neutralization, two factors-the densities of physical entanglements and of chemical crosslinks-both in UVI-treated PS should be considered for the perpendicular orientation of nanolamellae and nanocylinders in symmetric and asymmetric PS- b -PMMA thin films. The density of physical entanglement in PS depends intrinsically on M n of the PS, whereas the density of chemical cross-links was controlled with a varied duration of UVIN. Sufficiently large densities of physical entanglements and chemical cross-links can prevent PS- b -PMMA chains from penetrating through the neutral skin layer. The total density of physical entanglements and chemical cross-links required for the perpendicular orientation is correlated with the dimensions of the PS- b -PMMA chains.

This paper presents a series of molecular dynamics simulations of the evaporating process of an argon droplet on heated substrates and the energy transport mechanism through the solid-liquid interface. Results indicate that the mass density through the liquid-vapor interface decreases sharply when the evaporation is in the steady state. Meanwhile, there is an adsorption layer in the form of clusters at the solid-liquid interface, which has a higher mass density than the droplet inside. Furthermore, the wetting property of the solid substrate is related to the system's initial temperature and the solid-liquid potential energy parameter. The contact angle decreases with the increase of initial temperature and solid-liquid potential energy parameter. During the accelerated evaporation process, small part of energy transports into the liquid in the perpendicular direction to the solid-liquid interface and most of the energy transports along the parallel direction to the solid-liquid interface in the adsorption layer to the three-phase contact line. The heat-transfer process from the solid substrate to the droplet inside is hindered by the Kapitza resistance at the solid-liquid interface, no matter the solid substrate is hydrophilic or hydrophobic. Meanwhile, the Kapitza resistance gradually increases with the increase of the initial temperature and decreases with the increase of the solid-liquid energy parameter.

The development of efficient photothermal materials is the most important issue in solar water evaporation. In this work, melt electrospun reduced tungsten oxide/polylactic acid (WO 2.72 /PLA) fiber membranes were successfully prepared with improved near-infrared (NIR) photothermal conversion properties owing to strong NIR photoabsorption by the metal oxide. WO 2.72 powder nanoparticles were incorporated into PLA matrix by melt processing, following which the composites were extruded into wires using a single screw extruder. Subsequently, fiber membranes were prepared from the extruded wire of the WO 2.72 /PLA composite by melt electrospinning, which is a cost-effective technique that can produce fiber membranes without the addition of environmentally unfriendly chemicals. The melt electrospun WO 2.72 /PLA fiber membranes, floatable on water due to surface hydrophobicity, were systematically designed for, and applied to, vapor generation based on the interfacial concept of solar heating. With the photothermal WO 2.72 /PLA fiber membrane containing 7 wt % WO 2.72 nanoparticles, the water evaporation efficiency was reached 81.39%, which is higher than that for the pure PLA fiber membrane and bulk water. Thus, this work contributes to the development of novel photothermal fiber membranes in order to enhance light-driven water evaporation performance for potential applications in the fields of water treatment and desalination.

We investigated the relationship between the self-assembled morphology of poly( tert-butyl acrylate)- block-poly(6-[4-(4'-methoxyphenylazo)phenoxy]hexyl methacrylate) (P tBA- b-PAzoMA) block copolymers and their photoresponsive and fluorescence behaviors. The morphology of P tBA- b-PAzoMA copolymers was manipulated by dissolving them in mixed dimethylformamide (DMF)/hexanol solvents. When P tBA- b-PAzoMA was dissolved in DMF-rich (neutral) solvents, a favorable interaction between the DMF molecules and both blocks resulted in a random-coiled conformation. The unconfined morphology facilitated the formation of both nonassociated and head-to-head organized azobenzene mesogens, which promoted fluorescence emission. When hexanol, a P tBA-selective solvent, was added to DMF, the solvency of P tBA- b-PAzoMA worsened, leading to its assembly into micelles, with PAzoMA in the micelle core. The confinement of azobenzene moieties in the micelle core hindered their trans-to- cis photoisomerization, thereby considerably decreasing the kinetics of photoisomerization and the population of cis isomers. Additionally, a nanoconfined geometry resulted in compactly packed chromophores, causing fluorescence loss. When P tBA- b-PAzoMA was exposed to UV light, the increased number of cis isomers hampered the closely packed mesogens, resulting in a substantial enhancement of fluorescence emission. When the mole fraction of the PAzoMA block was increased, P tBA- b-PAzoMA formed clusters, causing the slow kinetics of photoisomerization and fluorescence quenching.

A large enhancement of the Ni and Cr ferromagnetic moments under UV-light irradiation has been detected in 55 nm thick K 0.98 Ni[Cr(CN) 6 ] 0.70 [(H 2 O) 6 ] 0.30 ·0.11H 2 O Prussian blue analogues coated on 240 nm Rb 0.76 Co[Fe(CN) 6 ] 0.74 [(H 2 O) 6 ] 0.26 ·0.56H 2 O nanocubes. Two separate magnetic transitions were found. The one at 72 K marks the magnetic ordering of the Ni and Cr ions on the shell. A higher degree of electronic connection along the Ni-N-C-Cr-C-N-Ni chains was achieved by the incorporation of a larger amount of K + ions into the voids enclosed by the NiN 6 and CrC 6 octahedra, which was used to understand the appearance of photoenhanced ferromagnetism in the K-Ni-Cr network. A weak moment developed in the core below 10 K, corresponding to separate ordering of the Co and Fe ions in the Rb-Co-Fe network. Photoinduced ferromagnetism of the Co and Fe ions in the Rb-Co-Fe was also detected., Competing Interests: The authors declare no competing financial interest.

The interactions between ions and phospholipids are closely associated with the structures and functions of cell membrane. Instead of conventional aqueous systems, we systematically investigated the effects of inorganic ions on the self-assembly of lecithin, a zwitterionic phosphatidylcholine, in cyclohexane. Previous studies have shown that addition of inorganic salts with specific divalent and trivalent cations can transform lecithin organosols into organogels. In this study, we focused on the effect of monovalent alkali halides. Fourier transform infrared spectroscopy was used to demonstrate that the binding strength of the alkali cations with the phosphate of lecithin is in the order Li + > Na + > K + . More importantly, the cation-phosphate interaction is affected by the paired halide anions, and the effect follows the series I - > Br - > Cl - . The salts of stronger interactions with lecithin, including LiCl, LiBr, LiI, and NaI, were found to induce cylindrical micelles sufficiently long to form organogels, while others remain organosols. A mechanism based on the charge density of ions and the enthalpy change of the ion exchange between alkali halides and lecithin headgroup is provided to explain the contrasting interactions and the effectiveness of the salts to induce organogelation.

PtSn alloy, which is a potential material for use in direct methanol fuel cells, can efficiently promote methanol oxidation and alleviate the CO poisoning problem. Herein, methanol decomposition on Pt3Sn(111) was systematically investigated using periodic density functional theory and microkinetic modeling. The geometries and energies of all of the involved species were analyzed, and the decomposition network was mapped out to elaborate the reaction mechanisms. Our results indicated that methanol and formaldehyde were weakly adsorbed, and the other derivatives (CHxOHy, x = 1-3, y = 0-1) were strongly adsorbed and preferred decomposition rather than desorption on Pt3Sn(111). The competitive methanol decomposition started with the initial O-H bond scission followed by successive C-H bond scissions, (i.e., CH3OH → CH3O → CH2O → CHO → CO). The Brønsted-Evans-Polanyi relations and energy barrier decomposition analyses identified the C-H and O-H bond scissions as being more competitive than the C-O bond scission. Microkinetic modeling confirmed that the vast majority of the intermediates and products from methanol decomposition would escape from the Pt3Sn(111) surface at a relatively low temperature, and the coverage of the CO residue decreased with an increase in the temperature and decrease in partial methanol pressure.

Tin dioxide (SnO2) and graphene are unique strategic functional materials with widespread technological applications, particularly in the areas of solar batteries, optoelectronic devices, and solid-state gas sensors owing to advances in optical and electronic properties. Versatile strategies for microstructural evolution and related performance of SnO2 and graphene composites are of fundamental importance in the development of electrode materials. Here we report that a novel composite, SnO2 quantum dots (QDs) supported by graphene nanosheets (GNSs), has been prepared successfully by a simple hydrothermal method and electron-beam irradiation (EBI) strategies. Microstructure analysis indicates that the EBI technique can induce the exfoliation of GNSs and increase their interlayer spacing, resulting in the increase of GNS amorphization, disorder, and defects and the removal of partial oxygen-containing functional groups on the surface of GNSs. The investigation of SnO2 nanoparticles supported by GNSs (SnO2/GNSs) reveals that the GNSs are loaded with SnO2 QDs, which are dispersed uniformly on both sides of GNSs. Interestingly, the electrochemical performance of SnO2/GNSs indicates that SnO2 QDs supported by a 210 kGy irradiated GNS shows excellent cycle response, high specific capacity, and high reversible capacity. This novel SnO2/GNS composite has potential practical applications in SnO2 electrode materials during Li(+) insertion/extraction.

In this work, a novel catalyst, Fe-species-loaded mesoporous manganese dioxide (Fe/M-MnO2) urchinlike superstructures, has been fabricated successfully in a two-step technique. First, mesoporous manganese dioxide (M-MnO2) urchinlike superstructures have been synthesized by a facile method on a soft interface between CH2Cl2 and H2O without templates. Then the M-MnO2-immobilized iron oxide catalyst was obtained through wetness impregnation and calcination. Microstructural analysis indicated that the M-MnO2 was composed of urchinlike hollow submicrospheres assembled by nanorod building blocks with rich mesoporosity. The Fe/M-MnO2 retained the hollow submicrospheres, which were covered by hybridized composites with broken and shortened MnO2 nanorods. Energy-dispersive X-ray microanalysis was used to determine the availability of Fe loading processes and the homogeneity of Fe in Fe/M-MnO2. Catalytic performances of the M-MnO2 and Fe/M-MnO2 were evaluated in catalytic wet hydrogen peroxide oxidation of methylene blue (MB), a typical organic pollutant in dyeing wastewater. The catalytic degradation displayed highly efficient discoloration of MB when using the Fe/M-MnO2 catalyst, e.g., ca. 94.8% of MB was decomposed when the reaction was conducted for 120 min. The remarkable stability of this Fe/M-MnO2 catalyst in the reaction medium was confirmed by an iron leaching test and reuse experiments. Mechanism analysis revealed that the hydroxyl free radical was responsible for the removal of MB and catalyzed by M-MnO2 and Fe/M-MnO2. MB was transformed into small organic compounds and then further degraded into CO2 and H2O. The new insights obtained in this study will be beneficial for the practical applications of heterogeneous catalysts in wastewater treatments.

Mesoporous TiO2 photocatalysts were prepared in ethanol media by using relatively green, template free sol-gel technique. A mild hydrothermal treatment procedure was employed to tune the pore sizes of the materials. Comprehensive techniques that include powder X-ray diffraction, diffuse reflectance spectroscopy, specific surface area analysis, electron microscopy, FT-IR, TGA, and ζ-potential measurements were used to characterize the titania materials. Porosity (pore size and pore volume) of the materials were found to be key factors for the variation in the rate of photocatalytic degradation of rhodamine B; in addition to specific surface area, and surface hydroxyl groups. An increase in porosity permits effective transport of the dye molecules resulting in an increase in the rate of the degradation in materials having larger pores. A detailed electrospray ionization-mass spectrometric (ESI-MS) study was carried out for selected materials to identify photodegraded intermediates and products formed during the degradation of rhodamine B. In addition, experiments were also carried out to understand the role of reactive oxygen species (ROS). In summary, this work provides a simple way to tune pore sizes without the use of any template and an insight into the influence of pore size for the photocatalytic degradation of rhodamine B.

The KDM4/JMJD2 Jumonji C-containing histone lysine demethylases (KDM4A-KDM4D), which selectively remove the methyl group(s) from tri/dimethylated lysine 9/36 of H3, modulate transcriptional activation and genome stability. The overexpression of KDM4A/KDM4B in prostate cancer and their association with androgen receptor suggest that KDM4A/KDM4B are potential progression factors for prostate cancer. Here, we report the crystal structure of the KDM4B·pyridine 2,4-dicarboxylic acid·H3K9me3 ternary complex, revealing the core active-site region and a selective K9/K36 site. A selective KDM4A/KDM4B inhibitor, 4, that occupies three subsites in the binding pocket is identified by virtual screening. Pharmacological and genetic inhibition of KDM4A/KDM4B significantly blocks the viability of cultured prostate cancer cells, which is accompanied by increased H3K9me3 staining and transcriptional silencing of growth-related genes. Significantly, a substantial portion of differentially expressed genes are AR-responsive, consistent with the roles of KDM4s as critical AR activators. Our results point to KDM4 as a useful therapeutic target and identify a new inhibitor scaffold.

To obtain a highly efficient and stable heterogeneous catalyst in catalytic wet hydrogen peroxide oxidation, we have successfully synthesized hierarchical mesoporous manganese dioxide (MnO2) superstructures by a facile and environmental friendly method on a soft-interface between CH2Cl2 and H2O without templates. The main crystal phase of as-prepared MnO2 was proved to be ε-MnO2 by X-ray diffraction techniques. The structure characterizations indicated that the hierarchical MnO2 superstructures were composed of urchin-like MnO2 hollow submicrospheres assembled by one-dimension nanorods building blocks with rich mesoporosity. The nitrogen sorption analysis confirmed that the as-synthesized MnO2 has an average pore diameter of 5.87 nm, mesoporous volume of 0.451 cm(3) g(-1), and specific surface area of 219.3 m(2) g(-1). Further investigations revealed that a possible formation mechanism of this unique hierarchical superstructure depended upon the synthesis conditions. The catalytic performances of the hierarchical mesoporous MnO2 superstructures were evaluated in catalytic degradation of methylene blue in the presence of H2O2 at neutral pH, which demonstrated highly efficient catalytic degradation of the organic pollutant methylene blue using hierarchical mesoporous MnO2 superstructures as catalyst at room temperature.

Nanocomposites have significant potential in the development of advanced materials for numerous applications. Tin dioxide (SnO2) is a functional material with wide-ranging prospects because of its high electronic mobility and wide band gap. Graphene as the basic plane of graphite is a single atomic layer two-dimensional sp(2) hybridized carbon material. Both have excellent physical and chemical properties. Here, SnO2 quantum dots/graphene composites have been successfully fabricated by a facile ultrasonic method. The experimental investigations indicated that the graphene was exfoliated and decorated with SnO2 quantum dots, which was dispersed uniformly on both sides of the graphene. The size distribution of SnO2 quantum dots was estimated to be ranging from 4 to 6 nm and their average size was calculated to be about 4.8 ± 0.2 nm. This facile ultrasonic route demonstrated that the loading of SnO2 quantum dots was an effective way to prevent graphene nanosheets from being restacked during the reduction. During the calcination process, the graphene nanosheets distributed between SnO2 nanoparticles have also prevented the agglomeration of SnO2 nanoparticles, which were beneficial to the formation of SnO2 quantum dots.

Results on Al-induced crystallization of amorphous Ge (a-Ge) deposited by vacuum thermal evaporation techniques under thermal annealing in N(2) atmosphere are presented in detail. The a-Ge crystallization and fractal Ge pattern formation on the free surface of annealed Al/Ge bilayer films deposited on single-crystal Si (100) substrates were investigated by using scanning electron microscopy (SEM), X-ray diffraction (XRD), atomic force microscopy (AFM), energy dispersive X-ray spectrometry (EDS), and Raman spectra. It is found that the temperature field effects play an extremely crucial role in a-Ge crystallization and fractal Ge formation process. The open branched structure of fractal Ge clusters in Al/Ge bilayer films was effectively prepared by Al-induced crystallization when they were annealed at 400 °C for 60 min. These films with fractal Ge clusters exhibit charming noninteger dimensional nanostructures, which differ from those of conventional integer dimensional materials such as one-dimensional nanowires/nanorods, nanotubes, nanobelts/nanoribbons, two-dimensional heterojunctions, thin films, and zero-dimensional nanoparticles. The SEM image shows that a big Al grain was found located near the center of a fractal Ge cluster after the films were annealed at 400 and 500 °C for 60 min. This suggests that the grain boundaries of polycrystalline Al films are the initial nucleation sites of a-Ge. It also validates the preferred nucleation theory of a-Ge at triple-point grain boundaries of polycrystalline Al at the interface. This discovery may be explained by the metal-induced nucleation (MIN) mechanism.

The stable, water-soluble, and nonfluorescent FA-OMe can sense nitric oxide (NO) and form the intensely fluorescent product dA-FA-OMe via reductive deamination of the aromatic primary amine. The reaction is accompanied by a notable increase of the fluorescent quantum yield from 1.5 to 88.8%. The deamination mechanism of FA-OMe with NO was proposed in this study. The turn-on fluorescence signals were performed by suppression of photoinduced electron transfer (PeT), which was demonstrated by density functional theory (DFT) calculations of the components forming FA-OMe and dA-FA-OMe. Furthermore, FA-OMe showed water solubility and good stability at physiological pHs. Moreover, the selectivity study indicated that FA-OMe had high specificity for NO over other reactive oxygen/nitrogen species. In an endogenously generated NO detection study, increasing the incubation time of FA-OMe with lipopolysaccharide (LPS) pretreated Raw 264.7 murine macrophages could cause an enhanced fluorescence intensity image. In addition, a diffusion/localization cell imaging study showed that FA-OMe could be trapped in Raw 264.7 cells. These cell imaging results demonstrated that FA-OMe could be used as a turn-on fluorescent sensor for the detection of endogenously generated NO.

Understanding size-dependent processes, including dissolution, of engineered nanoparticles is essential in addressing the potential environmental and health impacts of these materials as well as their long-term stability. In this study, experimental measurements of size-dependent dissolution of well-characterized zinc oxide (ZnO) nanoparticles with particle diameters in the range of 4 to 130 nm have been measured at circumneutral pH (pH 7.5) and compared. Dissolution was found to be enhanced with smaller ZnO nanoparticles compared to larger-sized particles, even though the nanoparticles were present in solution as aggregates with hydrodynamic diameters on the order of 1-3 μm in size. The presence of citric acid significantly enhanced the extent of ZnO dissolution for all sizes, and the greatest enhancement was observed for the 4 nm particles. Although these results are found to be in qualitative agreement with theoretical predictions, a linearized form of the Kelvin equation to calculate a surface free energy yielded quantities inconsistent with expected values from the literature. Reasons for this inconsistency are discussed and include potential deviations of solubility behavior from classical thermodynamics as a result of a lack of detailed knowledge of surface structure and surface properties, including the presence of different surface crystal facets, and the aggregation state.

NH(3) is a structural analogue of substrate H(2)O and an inhibitor to the water oxidation reaction in photosystem II. To test whether or not NH(3) is able to replace substrate water molecules on the oxygen-evolving complex in photosystem II, we studied the effects of NH(3) on the high-frequency region (3750-3550 cm(-1)) of the S(2)Q(A)(-)/S(1)Q(A) FTIR difference spectra (pH 7.5 at 250 K), where OH stretch modes of weak hydrogen-bonded active water molecules occur. Our results showed that NH(3) did not replace the active water molecule on the oxygen-evolving complex that gave rise to the S(1) mode at ~3586 cm(-1) and the S(2) mode at ~3613 cm(-1) in the S(2)Q(A)(-)/S(1)Q(A) FTIR difference spectrum of PSII. In addition, our mid-frequency FTIR results showed a clear difference between pH 6.5 and 7.5 on the concentration dependence of the NH(4)Cl-induced upshift of the S(2) state carboxylate mode at 1365 cm(-1) in the S(2)Q(A)(-)/S(1)Q(A) spectra of NH(4)Cl-treated PSII samples. Our results provided strong evidence that NH(3) induced this upshift in the spectra of NH(4)Cl-treated PSII samples at 250 K. Moreover, our low-frequency FTIR results showed that the Mn-O-Mn cluster vibrational mode at 606 cm(-1) in the S(2)Q(A)(-)/S(1)Q(A) spectrum of the NaCl control PSII sample was diminished in those samples treated with NH(4)Cl. Our results suggest that NH(3) induced a significant alteration on the core structure of the Mn(4)CaO(5) cluster in PSII. The implication of our findings on the structure of the NH(3)-binding site on the OEC in PSII will be discussed.

Metal/semiconductor thin films are a class of unique materials that have widespread technological applications, particularly in the field of microelectronic devices. New strategies of fractal assessment for Pd/Ge bilayer films formed at various annealing temperatures are of fundamental importance in the development of micro/nanodevices. Herein, Pd/Ge bilayer films with interesting fractal nanoclusters were successfully prepared by evaporation techniques. Temperature-dependent properties of resistance and fractal dimensions in Pd/Ge bilayer films with self-similar Ge fractal nanoclusters were investigated in detail. Experimental results indicated that the fractal crystallization behavior and film resistance in Pd/Ge bilayer films are influenced significantly by annealing temperatures and fractal dimensions. The measurements of film resistance confirmed that there is an evident relationship between the film resistance and the fractal dimension. These phenomena were reasonably explained by the random tunneling junction network mechanism.

The gas-phase reaction mechanisms of methylamine (MA) with the ground-state Co(+)((3)F) and Ni(+)((2)D) are theoretically investigated using density functional theory at both the B3LYP/6-311++G(d,p) and B3LYP/6-311++G(3df,2p) levels. The reactions for hydride abstraction and dehydrogenation are analyzed in terms of the topology of potential energy surfaces (PESs). Co(+) and Ni(+) perform similar roles along the isomerization processes to the final products. Hydride abstraction takes place via the key species of metal cation-methyl-H intermediate, followed by a charge transfer process before the direct dissociation of CH(2)NH(2)(+)···MH (M = Co, Ni). The enthalpies of reaction, stability of metal cation-methyl-H species, and competition between different channels account for the sequence of the hydride abstraction products: CoH < NiH < CuH. The most competitive dehydrogenation route occurs through a stepwise reaction, consisting of initial C-H activation, amino-H shift, and direct dissociation of the precursor CH(2)NHM(+)···H(2). This theoretical work sheds new light on the experimental observations and provides fundamental understanding of the reaction mechanisms of amine prototype with late first-row transition metal cations.

The interplay between the crystalline and magnetic structures of a 4% Cr-doped Bi(0.37)Ca(0.63)Mn(0.96)Cr(0.04)O(2.99) has been investigated by alternating current (ac) magnetic susceptibility, electrical resistivity, and neutron diffraction measurements. The compound crystallizes into a monoclinic P2(1)/m symmetry. A Jahn-Teller distortion occurs at 280 K. The thermal behavior of charge transport may be described by a three-dimensional variable range hopping conduction. Strong interplay between the localized magnetic electrons and the itinerant electrons are clearly revealed as the localization length increases by 20% when the Mn spins become ordered below 85 K. Short range magnetic correlations persist up to 160 K. The collinear magnetic structure can be viewed as consisting of ferromagnetic spin-trimers antiferromagnetically embedded in a ferromagnetic environment. Cr-doping reduces the charge ordering temperature and the magnetic ordering temperature. It nevertheless introduces long-range ferromagnetism.

A bacterium, Pseudomonas putida SH1, which can catabolize phenol, naphthalene, or cresol as the sole carbon and energy source, was isolated from a petroleum-contaminated site in Taiwan. The catechol 2,3-dioxygenase (C23O) was purified from this bacterial strain when grown on naphthalene as the sole carbon and energy source. The enzyme is composed of four identical subunits with a native molecular weight of 128 +/- 5 kD. Small-angle neutron scattering (SANS) techniques were employed to study the thermal effects on the structural conformation of this enzyme in solution. The SANS measurements revealed distinct changes in the size of the enzyme between 50 and 80 degrees C, and the size was not restored during the subsequent cooling. The enzyme started to denature at 55 degrees C, and the structure was destroyed by the time the temperature reached 80 degrees C, at which the enzyme had become more than twice the original size. The optimal catalytic temperature of the enzyme was at 50 degrees C. The half-life of the activity at this temperature was 45 min. The enzyme activity increases starting from 25 degrees C and reaches its maximum at 50 degrees C, below which no obvious change in the size of the enzyme is found. Noticeable enlargement of the enzyme is revealed when the enzymatic activity starts to fall. By combination of SANS measurement and biochemical properties of the enzyme, this study demonstrates the correlation of enzyme size in solution and catalytic activity upon a heat treatment. In addition, for a protein composed of multiple subunits, the shape of the enzyme and the dissociation of the enzyme subunits in a thermal cycle were also demonstrated by SANS methodology.

Molecular geometries, electronic structures, and optical absorption spectra were investigated using density functional theory (DFT) at the B3LYP/6-31G(d) and B3LYP/DZVP levels for [CuL(2)](+) and [CuL(2)][PF(6)] (L = 6,6'-dimethyl-2,2'-bipyridine-4,4'-dimethylformate), both in the gas phase and in methyl cyanide (MeCN) solution. The vertical excitation energies were calculated within the framework of the time-dependent DFT (TD-DFT) approach, whereas the solvent effects were taken into account using the polarizable continuum model (C-PCM). Our results show that the five highest occupied molecular orbitals (HOMOs) are composed of a set of distorted degenerate Cu 3d orbitals, whereas the four lowest unoccupied molecular orbitals (LUMOs) are the bipyridine ligand pi*(C horizontal lineN) orbitals. The spectra in the range of 400-600 nm were found to originate from metal-to-ligand charge-transfer (MLCT) transitions, whereas the spectra in the range of 350-400 nm are excitations mainly from the metal Cu 3d orbitals to the carboxyl pi* orbitals. The solvent effects lead to changes in both the geometries and the absorption spectra. The results of this work suggest that copper-based complexes might be effective sensitizers for next-generation dye-sensitized solar cells.

Sesamin, a lignan from sesame oil, has been shown to have antihypertensive and antioxidative properties. This study examined the effects of sesamin on oxidized low-density lipoprotein (oxLDL)-induced endothelial dysfunction. Oxidative stress was determined by measuring the generation of intracellular reactive oxygen species (ROS) and by measuring the expression levels of superoxide dismutase (SOD) and endothelial nitric oxide synthase (eNOS). To assess the pro-inflammatory effects of oxLDL, ELISA was used to detect IL-8 expression, endothelin-1 (ET-1) secretion, and nuclear factor-kappaB (NF-kappaB) activation. The expression of adhesion molecules (ICAM-1, VCAM-1, and E-selectin) was examined by flow cytometry. In addition, several apoptotic signaling pathways were also investigated. The data showed that sesamin significantly ameliorated oxLDL-induced ROS generation and SOD-1 inactivation. Sesamin also attenuated the oxLDL-induced activation of NF-kappaB, suggesting that the inhibitory effects of sesamin on IL-8 and ET-1 release, adhesion molecule expression, and the adherence of THP-1 cells were at least partially through the blockade of NF-kappaB activation. Furthermore, sesamin attenuated oxLDL-induced apoptotic features, such as intracellular calcium accumulation and the subsequent collapse of mitochondrial membrane potential, release of cytochrome c, and activation of caspase-3. Results from this study may provide insight into possible molecular mechanisms underlying sesamin's beneficial effects against oxLDL-mediated vascular endothelial dysfunction.

Liposome consisting of a single zwitterionic lipid as the potential vector for gene therapy has been reported recently; however, whether polyanionic DNA can bind directly with zwitterionic lipid without the aid of multivalent salt still remains unresolved. In this study, we reveal the aggregation of zwitterionic oligolamellar liposomes composed of 1,2-di(cis-9-octadecenoyl)-sn-glycero-3-phosphocholine induced by DNA without the presence of multivalent salt. Our results demonstrate that only a small fraction (<10%) of DNA can bind electrostatically with a portion of the liposomes. Such a low degree of binding, however, induces significant aggregation of these oligolamellar liposomes, yielding large multilamellar particles in which the number of hydrophilic/hydrophobic layer stacking becomes sufficiently large to yield multiple diffraction peaks in the small-angle X-ray scattering profile. Addition of monovalent salt such as NaCl tends to disrupt the multilamellar structure.

A mixture of soybean oil and/or water, sugar and/or monosodium glutamate (MSG) was water-boiled or oil-heated at 100, 120, 140, 160, or 170 degrees C, respectively, and volatile compounds produced were isolated by solid-phase microextraction and then identified by GC and GC/MS. Oxidative thermal degradation products of fatty acids (OTDPFA) were the major volatile compounds detected for all water-boiled samples. When MSG and sugar were heated together, 2, 5-dimethyl pyrazine and methyl pyrazine were also detected at or after 160 min heating. Water added in soybean oil increased OTDPFA production. In oil-heated samples of soybean oil alone, soybean oil with MSG, and soybean oil with sugar, OTDPFA were also the major compounds found. The samples containing MSG also produced 2-pyrrolidone, and the samples containing sugar also produced furfural and 5-hydroxy methyl furfural. The samples containing soybean oil, sugar, and MSG produced 23 pyrazines, OTDPFA, and gamma-butyrolactone as the major volatile compounds. The contents of OTDPFA were lower in MSG plus sugar and MSG-added samples, and it is postulated that antioxidant activities were produced in cooking.