Membrane distillation operated at high seawater concentration factors: Role of the membrane on CaCO3 scaling in presence of humic acid

This study aims at investigating the kinetics of calcium carbonate precipitation (scaling), that occurs in the form of vaterite, when treating seawater by direct contact membrane distillation (DCMD) operated at high concentration factors (from 4 to 6). Induction time measurements carried out by dynamic light scattering (DLS) allowed to identify the shifting between homogeneous and heterogeneous nucleation mechanisms as a function of supersaturation. CaCO₃ interfacial energy, evaluated for concentrated seawater solutions as 45 mJ/m², increased by 7% as a consequence of the inhibition effect of humic acid, and it was reduced to 32 mJ/m² in correspondence of heterogeneous nucleation occurring on microporous polypropylene membranes. Gibbs free energy barrier to the formation of critical nuclei was predicted with good accuracy as a function of physico-chemical properties of the membrane (porosity: 0.70, contact angle: 115 ± 2°).     

Dégradation photocatalytique des ions ammonium en présence de TiO2 dopé

A new process is proposed for the treatment of the nitrogenous compounds (NH₄⁺, NO₂^–et NO₃^–) in water, based upon the coupling of two catalytic reactions: the hydrogenation of NO₃^– and NO₂^– and the photooxidation of NH₄⁺. The present work is aimed at the study of the photooxidation part of the process. The effect of metals upon the activity and selectivity of TiO₂-based photocatalysts is investigated. The effect of pH, amount of TiO₂, temperature and concentration of ammonium and hydroxide ions on the photocatalytic activity and selectivity have been measured.     

The viscosity of the methanol-<Emphasis Type=Italic>n</Emphasis>-decane system in the region of low <Emphasis Type=Italic>n</Emphasis>-decane concentrations

The kinematic viscosity and density of the methanol-n-decane system were measured at various temperatures at low n-decane concentrations (over the miscibility range). The theory of free volume with taking into account molecular association was used to calculate the dynamic viscosity of this system at 298.15 K. The results substantiated the presence of an anomaly in this system (positive Δlnη values).     

Direct Electrochemistry of Glucose Oxidase at Reduced Graphene Oxide and β‐Cyclodextrin Composite Modified Electrode and Application for Glucose Biosensing

A simple glucose biosensor has been developed based on direct electrochemistry of glucose oxidase (GOx) immobilized on the reduced graphene oxide (RGO) and β‐cyclodextrin (CD) composite. A well‐defined redox couple of GOx appears with a formal potential of ～?0.459 V at RGO/CD composite. A heterogeneous electron transfer rate constant (K_s) has been calculated for GOx at RGO/CD as 3.8 s^?1. The fabricated biosensor displays a wide response to glucose in the linear concentrations range from 50 µM to 3.0 mM. The sensitivity and limit of detection of the biosensor is estimated as 59.74 µA mM^?1 cm^?2 and 12 µM, respectively.     

Two New Flavonoids from Retama raetam

Two new furanoflavonoids, retamasins A and B ( 1 and 2 , resp.), along with five known flavonoids, 3 – 7 , were isolated from the aerial parts of Retama raetam. Their structures were determined on the basis of extensive spectroscopic (IR, MS, and 1D‐ and 2D‐NMR) analyses and by comparison with the literature data. This is the first report of the isolation of new furanoflavonoids 1 and 2 from Retama genus, while compounds 3, 5 , and 6 were found for the first time from R. raetam. Antioxidant and anti‐inflammatory activities of the isolated compounds were also evaluated. Compounds 2, 3 , and 5 – 7 exhibited potent inhibitions of iNOS activity with IC₅₀ values of 2.9, 5.0, 3.1, 1.2, and 4.8 μg/ml, respectively. All compounds inhibited NF‐κB except 1 and 5 . Compound 6 was most active in inhibiting iNOS and NF‐κB activity, as well as in decreasing oxidative stress.     

Towards Ratiometric Sensing of Amyloid Fibrils In Vitro

The aggregation of amyloid‐β peptide and its accumulation in the human brain has an important role in the etiology of Alzheimer’s disease. Thioflavin T has been widely used as a fluorescent marker for these amyloid aggregates. Nevertheless, its complex photophysical behavior, with strong wavelength dependencies of all its fluorescence properties, requires searching for new fluorescent probes. The use of 2‐(2′‐hydroxyphenyl)imidazo[4,5‐b]pyridine (HPIP), which shows two emission bands and a rich excited‐state behavior due to the existence of excited‐state intramolecular processes of proton transfer and charge transfer, is proposed. These properties result in a high sensitivity of HPIP fluorescence to its microenvironment and cause a large differential fluorescence enhancement of the two bands upon binding to aggregates of the amyloid‐β peptide. Based on this behavior, a very sensitive ratiometric method is established for the detection and quantification of amyloid fibrils, which can be combined with the monitoring of fluorescence anisotropy. The binding selectivity of HPIP is discussed on the basis of the apparent binding equilibrium constants of this probe to amyloid‐β (1–42) fibrils and to the nonfibrillar protein bovine serum albumin. Finally, an exhaustive comparison between HPIP and thioflavin T is presented to discuss the sensitivity and specificity of these probes to amyloid aggregates and the significant advantages of the HPIP dye for quantitative determinations.     

Ab initio calculations of the ground and excited states of the ZrN molecule including spin‐orbit effects

The electronic structures with spin‐orbit effects of the zirconium nitride ZrN molecule are investigated by the methods of multireference single and double configuration interaction. The potential energy curves are calculated along with the spectroscopic constants for the lowest‐lying 34 spin‐orbit states Ω in ZrN. A good agreement is displayed by comparing the calculated spectroscopic constants with those available experimentally. The permanent dipole moments are calculated along with the vibrational energies. New results are obtained in this work for 29 spin‐orbit states and their spectroscopic constants calculated. © 2015 Wiley Periodicals, Inc.     

Synthesis,Antimicrobial, and Brine Shrimps Lethality Assays of 3,3‐Diaryl‐4‐(1‐methyl‐1H‐indol‐3‐yl)azetidin‐2‐ones

The paper describes the synthesis, characterization data, and biological activity (antibacterial, antifungal, and brine shrimps lethality) of new azetidin‐2‐ones. The compounds have been synthesized by the reaction of diarylketenes, generated in situ from thermal decomposition of the 2‐diazo‐1,2‐diarylethanones, with N‐(1‐methyl‐1H‐indol‐3‐yl)methyleneamines. The compounds have been characterized by elemental analysis and spectral (IR, ¹H and ¹³C NMR, and MS) data. The paper also reports the results of antibacterial, antifungal, and brine shrimps lethality assays of these compounds. Some of the compounds exhibited significant biological activity.     

Bimetallic Cyclometalated Iridium(III) Diastereomers with Non‐Innocent Bridging Ligands for High‐Efficiency Phosphorescent OLEDs

Two phosphorescent dinuclear iridium(III) diastereomers (ΛΔ/ΔΛ) and (ΛΛ/ΔΔ) are readily separated by making use of their different solubilities in hot hexane. The bridging diarylhydrazide ligand plays an important role in the electrochemistry and photophysics of the complexes. Organic light‐emitting devices (OLEDs) that use these complexes as the green‐emissive dopants in solution‐processable single‐active‐layer architectures feature electroluminescence efficiencies that are remarkably high for dinuclear metal complexes, achieving maximum values of 37 cd A^?1, 14 lm W^?1, and 11 % external quantum efficiency.