Templated Synthesis of Composite Rings Using Core‐Shell Toroids

In difference to compact objects of a similar size, toroidal structures have some distinguishing properties that originate from their open inner cavity and closed circuit. Here, a general facile methodology is developed to prepare composite rings with varied compositions on a large scale by using core‐shell toroids assembled from tri‐block copolymers of poly(4‐vinyl pyridine) (PVP)/polystyrene (PS)/PVP. Taking advantage of the complexation ability of the PVP shell, varied components that range from polymers, inorganic materials, metals and their compounds, as well as pre‐formed nanoparticles are introduced to the toroidal structures to form composite nanostructures. Metal ions can be adsorbed by PVP through complexation. After in situ reduction, a large number of metal‐based functional materials can be prepared. PVP is alkaline, and thus capable of catalyzing the sol‐gel process to generate an inorganic shell. Furthermore, pre‐formed nanoparticles can also be absorbed by the shell through specific interactions. The PS core is not infiltrative during synthesis, and hollow rings can be derived after the polymer templates are removed.

     

N-Doped Carbon Nanofibrous Film with Unique Wettability,Enhanced Supercapacitive Property,and Facile Capacity to Demulsify Surfactant Free Oil-in-water Emulsions

Electrospinning and calcination technique have been combined to fabricate N-doped carbon nanofibers(N-CNFs) by introducing amino grafted few-layered hexagonal boron nitride (amino@BN) into polyacrylonitrile(PAN) matrix as filler followed by carbonization. For the high N-doping level(10.7%, atomic fraction) with the final product, the as-prepared N-CNFs exhibit interesting surface wettability(superamphiphilicity in air and underwater oleophilicity). Moreover, compared with pristine PAN derived carbon nanofibers(marked as CNFs), N-CNFs exhibit higher graphic structure under fixed carbonizing temperature as well. Taking these advantages aforementioned, the as-prepared N-CNFs exhibit good specific capacitance(ca. 200.1 F/g) without activation treatment at the current density of 0.5 A/g in three-electrode configuration, which is about 149% that of CNFs(ca. 134 F/g). What's more, our N-CNFs also display the unexpected capacity to demulsify diverse surfactant free oil-in-water emulsions by simple filtration in large scale with the high water flux ca.(23578±150) L·m^-2·h^-1.     

Simple copper/TEMPO catalyzed aerobic dehydrogenation of benzylic amines and anilines

CuBr(2) with 2,2,6,6-tetramethylpiperidyl-1-oxy (TEMPO) has been successfully employed for the aerobic oxidation of primary and secondary benzyl amines in aqueous acetonitrile. Such catalytic systems have previously been used extensively in alcohol oxidation reactions. The same catalyst system was also used for oxidative cross-couplings of benzylamines with anilines. The electronic and steric properties of the aniline partner were found to be of crucial importance in determining reactivity or lack thereof. A mechanism for these reactions is proposed based on the data obtained to date. In the absence of benzyl amines, electron-rich anilines were found to undergo dehydrogenative coupling and yields of the resulting azo products could be increased by replacing CuBr(2) with CuBr. No ligand (e.g. pyridine) is required for either reaction to proceed and presumably water and acetonitrile solvate the copper-containing intermediates.     

A microporous metal-organic framework with FeS(2) topology based on [Zn6(μ6-O)] cluster for reversible sensing of small molecules

The first luminescent metal-organic framework (MOF) with [Zn(6)(μ(6)-O)] cluster has been synthesized and realized for reversible sensing of small molecules.     

Aligned coaxial tungsten oxide-carbon nanotube sheet: a flexible and gradient electrochromic film

We develop a simple dry wrapping method to fabricate a tungsten oxide (WO(3))/carbon nanotube (CNT) cable, in which WO(3) layers act as an electrochromic component while aligned CNTs as the core provide mechanical support and an anisotropic, continuous electron transport pathway. Interestingly, the resultant cable material exhibits an obvious gradient electrochromic phenomenon.     

Isolation and characterization of an exopolygalacturonase from Fusarium oxysporum f.sp. cubense race 1 and race 4

Background

Previously, we have reported the presence of highly sulfated dermatans in solitary ascidians from the orders Phlebobranchia (Phallusia nigra) and Stolidobranchia (Halocynthia pyriformis and Styela plicata). Despite the identical disaccharide backbone, consisting of [→4IdoA(2S)β-1→3GalNAcβ-1→], those polymers differ in the position of sulfation on the N-Acetyl galactosamine, which can occur at carbon 4 or 6. We have shown that position rather than degree of sulfation is important for heparin cofactor II activity. As a consequence, 2,4- and 2,6-sulfated dermatans have high and low heparin cofactor II activities, respectively. In the present study we extended the disaccharide analysis of ascidian dermatan sulfates to additional species of the orders Stolidobranchia (Herdmania pallida, Halocynthia roretzi) and Phlebobranchia (Ciona intestinalis), aiming to investigate how sulfation evolved within Tunicata. In addition, we analysed how heparin cofactor II activity responds to dermatan sulfates containing different proportions of 2,6- or 2,4-disulfated units.

Results

Disaccharide analyses indicated a high content of disulfated disaccharide units in the dermatan sulfates from both orders. However, the degree of sulfation decreased from Stolidobranchia to Phlebobranchia. While 76% of the disaccharide units in dermatan sulfates from stolidobranch ascidians are disulfated, 53% of disulfated disaccharides are found in dermatan sulfates from phlebobranch ascidians. Besides this notable difference in the sulfation degree, dermatan sulfates from phlebobranch ascidians contain mainly 2,6-sulfated disaccharides whereas dermatan sulfate from the stolidobranch ascidians contain mostly 2,4-sulfated disaccharides, suggesting that the biosynthesis of dermatan sulfates might be differently regulated during tunicates evolution. Changes in the position of sulfation on N-acetylgalactosamine in the disaccharide [→4IdoA(2-Sulfate)β-1→3GalNAcβ-1→] modulate heparin cofactor II activity of dermatan sulfate polymers. Thus, high and low heparin cofactor II stimulating activity is observed in 2,4-sulfated dermatan sulfates and 2,6-sulfated dermatan sulfates, respectively, confirming the clear correlation between the anticoagulant activities of dermatan sulfates and the presence of 2,4-sulfated units.

Conclusions

Our results indicate that in ascidian dermatan sulfates the position of sulfation on the GalNAc in the disaccharide [→4IdoA(2S)β-1→3GalNAcβ-1→] is directly related to the taxon and that the 6-O sulfation is a novelty apparently restricted to the Phlebobranchia. We also show that the increased content of [→4IdoA(2S)β-1→3GalNAc(4S)β-1→] disaccharide units in dermatan sulfates from Stolidobranchia accounts for the increased heparin cofactor II stimulating activity.     

Janus hollow spheres by emulsion interfacial self-assembled sol-gel process

Janus hollow silica spheres with an asymmetric shell are synthesized by self-assembled sol-gel process at an emulsion interface, and desired materials can be preferentially laden inside the cavities from their surroundings.     

A Facile Synthesis of Unsymmetrical Sulfides Under Phase Transfer Conditions

An efficient synthesis of unsynmetrical sulfides (3) is described by reacting S-alkylisothiouroniu″ salts (1) with alkyl halides (2) under liquid-liquid phase transfer catalyst conditions.     

Novel calibration method for non-overlapping multiple vision sensors based on 1D target

The global calibration of multiple vision sensors (MVS) with non-overlapping views has been widely studied. In this paper, a novel calibration method for MVS with non-overlapping fields of view based on 1D target is presented. First, two neighboring vision sensors are selected. The rotation matrix between the two vision sensors is computed using the co-linearity property of the feature points on 1D target. Then the translation vector is computed according to the known distances between feature points on 1D target. The global calibration of all vision sensors is realized by repeating the above pair-wise calibration on different pairs of vision sensors. Due to the small volume and mobility of 1D target, the proposed global calibration method can be applied to vision sensors distributed in a large area or narrow space. Experiment results show that the RMS error of global calibration is within 0.060 mm.     

A novel calibration approach to structured light 3D vision inspection

Structured light 3D vision inspection is a commonly used method for various 3D surface profiling techniques. In this paper, a novel approach is proposed to generate the sufficient calibration points with high accuracy for structured light 3D vision. This approach is based on a flexible calibration target, composed of a photo-electrical aiming device and a 3D translation platform. An improved algorithm of back propagation (BP) neural network is also presented, and is successfully applied to the calibration of structured light 3D vision inspection. Finally, using the calibration points and the improved algorithm of BP neural network, the best network structure is established. The training accuracy for the best BP network structure is 0.083 mm, and its testing accuracy is 0.128 mm.