Three new five-coordinated mercury (II) dyes: Structure and enhanced two-photon absorption

A new donor-bridge-acceptor (D-π-A) type ligand (L: 4′-(4-[4-(imidazole)styryl]phenyl)-2,2′:6′,2″-terpyridine) with two-photon absorption and coordination ability was designed and synthesized. Self-assembly of the ligand with HgX₂ (X = Cl, Br, I) yielded a series of new coordination complexes (Dyes 1-3) with five-coordinated mercury (ΙΙ), which were characterized by single crystal X-ray diffraction determination. Solvent molecules and various weak interactions, including hydrogen bonds (C-H···N, C-H···X) and π-π interactions played significant roles in the final topological structures. Linear and nonlinear optical properties of the ligand and three dyes were described. Experimental results revealed that two-photon absorption cross sections of three dyes are extraordinary stronger than that of ligand.     

Structure, dynamics and interactions of complex sol-gel hybrid materials through SSNMR and DSC: Part II, ternary systems based on PE-PEG block copolymer, PHS and silica

This work is the second part of a study aimed at understanding in more depth structure, dynamics, interactions and correlations between morphology and barrier properties against oxygen diffusion of complex PE-PEG/PHS/SiO₂ hybrids prepared through a sol-gel process. Using a combined DSC and solid-state NMR approach, including ¹³C and ²⁹Si experiments and ¹H ultra-fast MAS spectra, the structural, phase and interaction properties of three PE-PEG/PHS/SiO₂ samples with different compositions, exhibiting different barrier performances, have been investigated, also taking into account the results obtained for the simpler one- and two-component systems (Part I). While the structure of the silica domains has been found to be not affected by composition, many differences have been observed concerning the phase and dynamic properties of the organic components (PE and PEG crystallinity and mobility of their amorphous domains) and the inter-component interactions (strength of the hydrogen bonds between PHS and both silica and PEG and PHS/PEG miscibility). In particular peculiar phase and interaction properties of the sample exhibiting the best barrier properties have been identified and characterized.     

硅橡胶涂料憎水迁移特性的分析

RTV（室温硫化硅橡胶涂料）是一种新型的长效防污涂料，其防污的根本特性在于其优异的憎水性和憎水迁移性，即当RTV涂料表面有了灰之后，RTV本身的增水性可以迁移到左表面，从而使得灰表面屯有了憎水性，可以大大提高污闪电压。本文详尽的分析了可能影响RTV涂料憎水迁移特性的因素，并结合现代分析手段，提出了RTV涂料迁移机理的假说。     

Induction of Systemic Acquired Resistance in Cotton Foliage Does Not Adversely Affect the Performance of an Entomopathogen

Baculoviral efficacy against lepidopteran larvae is substantially impacted by the host plant. Here, we characterized how baculoviral pathogenicity to cotton-fed Heliothis virescens larvae is affected by induction of systemic acquired resistance (SAR). Numerous studies have shown that SAR induced by the plant elicitor benzo-(1,2,3)-thiadiazole-7-carbothioic acid S-methyl ester (BTH) can protect against plant pathogens, but reports on the impacts of SAR on chewing herbivores or on natural enemies of herbivores are few. We found that BTH application significantly increased foliar peroxidase activity, condensed tannin levels, and total phenolic levels but did not alter dihydroxyphenolic levels. Consumption of BTH-treated foliage did not influence H. virescens pupal weight or larval mortality by the microbial control agent Autographa californica multiple nucleopolyhedrovirus any more than did consumption of untreated foliage. Thus, activation of SAR, although it did not protect the plant against a chewing herbivore, also did not reduce the effect of a natural enemy on a herbivore, indicating that SAR and microbial control agents may be compatible components of integrated pest management.     

Promotional effects on a PtRu/C catalyst-electrode interfaced with aqueous electrolytes: electrochemical metal support interaction (EMSI) and electrochemical promotion of catalysis (EPOC)

The kinetics of the catalytic oxidation of H₂ on PtRu/C gas diffusion electrode (GDE) was studied by interfacing the electrode with aqueous electrolytes at different pH values. The conducting electrolytes were aqueous solutions of varying concentrations of KOH and HClO₄ so that the pH was ranging between 2 and 13. The open circuit catalytic reaction rates exhibit the lowest value at pH = 13, while the catalytic activity is progressively increasing with decreasing pH values. The enhancement of the open circuit catalytic reaction rate can be even an order of magnitude higher in the acidic solution with respect to the alkaline electrolyte. It is shown that the nature of the aqueous electrolyte plays the role of an active catalyst support for the PtRu/C electrode, which drastically affects its catalytic properties. This is substantiated through the electrochemical equilibrium charge transfer reactions at the catalyst-electrode/electrolyte interface:

Specificity of Lipoprotein Chaperones for the Characteristic Lipidated Structural Motifs of their Cognate Lipoproteins

Lipoprotein‐binding chaperones mediate intracellular transport of lipidated proteins and determine their proper localisation and functioning. Understanding of the exact structural parameters that determine recognition and transport by different chaperones is of major interest. We have synthesised several lipid‐modified peptides, representative of different lipoprotein classes, and have investigated their binding to the relevant chaperones PDEδ, UNC119a, UNC119b, and galectins‐1 and ‐3. Our results demonstrate that PDEδ recognises S‐isoprenylated C‐terminal peptidic structures but not N‐myristoylated peptides. In contrast, UNC119 proteins bind only mono‐N‐myristoylated, but do not recognise doubly lipidated and S‐isoprenylated peptides at the C terminus. For galectins‐1 and ‐3, neither binding to N‐acylated, nor to C‐terminally prenylated peptides could be determined. These results shed light on the specificity of the chaperone‐mediated cellular lipoprotein transport systems.     

Wettability of Surface Oxyfluorinated Polypropylene Fibres and Its Effect on Interfacial Bonding with Cementitious Matrix

The surface of high molecular weight polypropylene monofilament fibre was modified using a oxyfluorination method. The oxyfluorination treatment level was varied and a hydrolysis post-treatment was also applied. Contact angles of oxyfluorinated, hydro-lyzed oxyfluorinated and unmodified polypropylene fibres were obtained by dynamic contact angle (DCA) measurement using three liquids of known dispersion, acid and base surface free energy components. The surface free energies were then calculated according to the acid-base theory developed by Good, van Oss and Chaudhury. Surface oxyfluorination largely increased the acid and base components of the fibres' surface free energy compared with unmodified polypropylene fibres. The oxyfluorinated and unmodified polypropylene fibre surfaces were observed by Scanning Electronic Microscopy and Photoacoustic Infrared Spectroscopy. It was found that the surface oxyfluorination largely increases the roughness of the polypropylene surfaces and the carbonyl group content increases as the treatment level increases. The interfacial shear bond strengths between the cementitious matrix and the polypropylene fibres treated under various conditions were determined by embedded fibre pull-out tests. Results showed that the fibre surface oxyfluorination treatments increase the interfacial bond strengths. The correlations between the shear bond strengths and surface free energy components were established. Results showed that fibre/concrete interfacial bonding was best correlated with the acid component of surface free energy of polypropylene fibres.     

The Use of Monochromated XPS to Evaluate Acid-Base Interactions at the PMMA/Oxidised Metal Interface

Recent studies have proposed that a near-interface conformation of PMMA in PMMA/metal substrate systems is different from the bulk polymer. High-resolution XPS analysis using monochromated X-ray sources has shown that PMMA interactions with metal oxide substrates are determined by the acido-basic nature of the substrate. It has also been shown that PMMA interacts with acidic sites on oxidised silicon via the carbonyl oxygen, and strongly basic sties on oxidised copper and nickel will react with the carboxyl carbon via nucleophilic attack. On amphoteric substrates, such as oxidised iron and aluminium, it is proposed that hydrolysis of the methyl ester occurs at weak basic sites to form a carboxylate, resulting in complexes being formed with the metal substrate. Such acid-base interactions would result in the orientation of PMMA at the interface to be dependent on the acido-basic nature of the substrate. This study also shows the resolution of a microfocussed monochromated X-ray source retrofitted to an older XPS spectrometer to be close to that of the Scienta ESCA 300 instrument.     

Preparation of Functionalized Polymersomes and the In Vivo Imaging

Recently, polymersomes self-assembled from amphiphilic block copolymers have attracted considerable interests with superior physicochemical properties. Here, the biotinylated block copolymers were blended with unmodified block copolymers to produce biotinylated polymersomes via film rehydration. Then, the avidin molecules were attached onto the biotin molecules covalently linked with block copolymers to form surface functionalized vesicles that are capable of carrying various biotinylated bioactive molecules, generating a relatively universal delivery platform. Hydrophobic fluorophores DAF and Nile Red were encapsulated respectively into hydrophobic membrane to prepare hydrophobic substances loaded polymersomes for investigating the nature of hydrophobic functionalization. Furthermore, the hydrophobic functionalized DiR-polymersomes were employed to perform in vivo imaging to survey the in vivo behavior for nano-polymersomes with hydrophobic functionalization.     

Hydrophobic Flocculation Flotation for Beneficiating Fine Coal and Minerals

ABSTRACT

It is shown that hydrophobic flocculation flotation (HFF) is an effective process to treat finely ground ores and slimes so as to concentrate coal and mineral values at a fine size range. The process is based on first dispersing the fine particles suspension, followed by flocculation of fine mineral values or coal in the form of hydrophobic surfaces either induced by specifically adsorbed surfactants or from nature at the conditioning of the slurry with the shear field of sufficient magnitude. The flocculation is intensified by the addition of a small amount of nonpolar oil. Finely ground coals, ilmenite slimes, and gold finely disseminated in a slag have been treated by this process. Results are presented indicating that cleaned coal with low ash and sulfur remaining and high Btu recovery can be obtained, and the refractory ores of ilmenite slimes and fine gold-bearing slag can be reasonably concentrated, leading to better beneficiation results than other separation techniques. In addition, the main operating parameters affecting the HFF process are discussed.