Donor‐Stabilized Phosphenium Adducts as New Efficient and Immobilizing Ligands in Palladium‐Catalyzed Alkynylation and Platinum‐Catalyzed Hydrogenation in Ionic Liquids

The straightforward synthesis of a new donor‐stabilized phosphenium ligand 3d by addition of bromodifurylphosphine to 1,3‐dimethylimidazolium‐2‐carboxylate 1 is described. The obtained ligand exhibits a very strong π‐acceptor character, comparable to that of triphenyl phosphite [P(OPh)₃] or of tris‐halogenophosphines, with a ν_CO(A₁) at 2087 cm⁻¹ for its nickel tricarbonyl complex. This ligand, as well as the related 3a which was obtained from chlorodiphenylphosphine, were tested in palladium‐catalyzed aryl alkynylation and in the platinum‐catalyzed selective hydrogenation of chloronitrobenzenes, both in an ionic liquid phase. In C C bond cross‐coupling we observed that the increase of the π‐acceptor character in ligand 3d , due to the introduction of an additional electron‐withdrawing group, provides a very efficient catalyst in the alkynylation reaction of aryl bromides with phenylacetylene, including the deactivated 4‐bromoanisole or the sterically hindered 2‐bromonaphthalene. The catalytic activity decreases with recycling due to the sensitiveness of ligands to protonation in the ionic phase. Conversely, a multiple recycling of the metal/ligand system in non‐acidic media was achieved from platinum‐catalyzed hydrogenation of m‐chloronitrobenzene. The catalytic results obtained by employing the complex of platinum(II) chloride with 3a [trans‐PtCl₂( 3a )₂] in comparison with the non‐ionic related trans‐tris(triphenylphosphine)platinum dichloride [trans‐PtCl₂(PPh₃)₂] complex clearly indicate that the simultaneous existence of a strong π‐acceptor character and a positive charge within the ligand 3a significantly increases the life‐time of the platinum catalyst. The selectivity of the reaction is also improved by decreasing the undesirable formation of dehalogenation products. This cationic platinum complex trans‐PtCl₂( 3a )₂ is the first example of a highly selective catalyst for hydrogenation of chloronitroarenes immobilized in an ionic liquid phase. The system was recycled six times without noticeable metal leaching in the organic phase, and no loss of activity.     

Aflatoxin Exposure during Early Life Is Associated with Differential DNA Methylation in Two-Year-Old Gambian Children

Background: DNA methylation is an epigenetic control mechanism that may be altered by environmental exposures. We have previously reported that in utero exposure to the mycotoxin and liver carcinogen aflatoxin B1 from the maternal diet, as measured using biomarkers in the mothers’ blood, was associated with differential DNA methylation in white blood cells of 6-month-old infants from The Gambia. Methods: Here we examined aflatoxin B1-associated differential DNA methylation in white blood cells of 24-month-old children from the same population (n = 244), in relation to the child’s dietary exposure assessed using aflatoxin albumin biomarkers in blood samples collected at 6, 12 and 18 months of age. HM450 BeadChip arrays were used to assess DNA methylation, with data compared to aflatoxin albumin adduct levels using two approaches; a continuous model comparing aflatoxin adducts measured in samples collected at 18 months to DNA methylation at 24 months, and a categorical time-dose model that took into account aflatoxin adduct levels at 6, 12 and 18 months, for comparison to DNA methylation at 24 months. Results: Geometric mean (95% confidence intervals) for aflatoxin albumin levels were 3.78 (3.29, 4.34) at 6 months, 25.1 (21.67, 29.13) at 12 months and 49.48 (43.34, 56.49) at 18 months of age. A number of differentially methylated CpG positions and regions were associated with aflatoxin exposure, some of which affected gene expression. Pathway analysis highlighted effects on genes involved with with inflammatory, signalling and growth pathways. Conclusions: This study provides further evidence that exposure to aflatoxin in early childhood may impact on DNA methylation.     

Micro-mechanical modelling of alkali-silica-reaction-induced degradation using the AMIE framework

AMIE, a finite element/extended finite element framework, has been designed to provide the tools to run detailed microstructural simulations; this paper demonstrates the possibility of simulating the mechanisms underlying the alkali-silica-reaction (ASR). The numerical model presented provides a better understanding of experimental observations. Macroscopic free expansion and degradation of mechanical properties have been previously linked to the extent of reaction. The connection between microscopic and macroscopic measurements, simulated by the model, supports the hypothesis that damage is induced by growing gel pockets in the aggregates.     

How Bromate and Ozone Concentrations Can be Modeled at Full-Scale Based on Lab-Scale Experiments – A Case Study

This article presents a full-scale modeling study of an industrial ozonation unit for practical application. The modeling framework combines an integrated hydraulic model (systematic network) with a quasi-mechanistic chemical model. Dealing with natural water, the chemical model has to be parameterized, and the parameters calibrated. This was done based on lab-scale experiments. The calibration results showed that the chemical model is able to account for changes in contact time with ozone, pH, temperature, ozone dose, NOM concentration, bromide concentration. Comparison of residence time distributions showed that the hydraulic model accurately reproduces flow conditions. Six sampling points were installed along an industrial ozonation unit of 487 m³ consisting of two baffled tanks in series. Bromate and ozone concentrations were monitored under varying operational process conditions. After the selection of a value for the k_La, simulations were run. Using the lab-scale calibrated models, simulated and experimental data were found in close agreement: 84% of the simulated concentrations for ozone matched measurements (±experimental error), 60 % for bromate. A readjustment of the kinetics of a single reaction (out of 65) showed that seasonal changes in NOM activity may easily be taken into account based on regular concentration measurements (90% of the bromate concentrations were then modeled accurately).     

Impact of free light chain hemodialysis in myeloma cast nephropathy: a case-control study

New very high permeability dialysis membranes have been developed to enable the clearance of free light chains in myeloma cast nephropathy. These new dialysis techniques, in combination with chemotherapy, should allow improved prognosis in patients with myeloma cast nephropathy. We report a prospective observational study comparing patients who underwent hemodialysis in our center in 2009 for cast nephropathy revealing multiple myeloma vs. patients treated for the same condition during the same period in other centers in our region. The main difference in the management protocols was the use of high cutoff (HCO) membranes in our center. We described the clinical features, the management protocols, and the outcomes as of June 1, 2010. In 2009, five patients were treated for myeloma cast nephropathy with HCO hemodialysis in our center. At 386 ± 100 days follow‐up, one patient died, while three of the five patients recovered their renal function, allowing cessation of hemodialysis. During the same period, five patients were treated for myeloma cast nephropathy in other centers in our region. At 398 ± 131 days follow‐up, four patients died, and none of the patients recovered renal function, allowing cessation of hemodialysis. In our study, light chain clearance allowed recovery of renal function and cessation of hemodialysis in three of five patients with acute kidney injury secondary to myeloma cast nephropathy. A randomized trial comparing this technique with conventional hemodialysis techniques should be conducted to raise the level of proof for this therapeutic option. The overall prognosis, including quality of life and cost‐effectiveness, of HCO hemodialysis should also be examined.     

Low temperature solid oxide fuel cells with pulsed laser deposited bi-layer electrolyte

Solid oxide fuel cells (SOFC) using a pulsed laser deposited bi-layer electrolyte have been successfully fabricated and have shown very good performance at low operating temperatures. The cell reaches power densities of 0.5 W cm⁻² at 550 °C and 0.9 W cm⁻² at 600 °C, with open circuit voltage (OCV) values larger than 1.04 V. The bi-layer electrolyte contains a 6–7 μm thick samarium-doped ceria (SDC) layer deposited over a ∼1 μm thick scandium-stabilized zirconia (ScSZ) layer. The electrical leaking between the anode and cathode through the SDC electrolyte, which due to the reduction of Ce⁴⁺ to Ce³⁺ in reducing environment when using a single layer SDC electrolyte, has been eliminated by adopting the bi-layer electrolyte concept. Both ScSZ and SDC layers in the bi-layer electrolyte prepared by the pulsed laser deposition (PLD) technique are the highly conductive cubic phases. Poor conductive (Zr, Ce)O₂-based solid solutions or β-phase ScSZ were not found in the bi-layer electrolyte prepared by the PLD due to low processing temperatures of the technique. Excellent reliability and flexibility of the PLD technique makes it a very promising technique for the fabrication of thin electrolyte layer for SOFCs operating at reduced temperatures.     

Synthesis and characterization of new proton exchange membrane deriving from sulfonated polyether sulfone using ionic crosslinking for electrodialysis applications

In this research work, the synthesis and characterization of new ion exchange membranes made from sulfonated polyether sulfone (S PES) crosslinked by aminated PES (NH2 PES) crosslinking reagent have been investigated for electrodialysis (ED) applications. Sulfonated and aminated PES have similar chemical structures that allow a good compatibility, the only difference between them is their functional groups. This membrane (called HNH2) has been obtained by reaction between S PES with 1.3 SO₃H groups per monomer unit and the calculated equivalent amount of NH2 PES. Three HNH2 membranes have been fabricated with different degrees of sulfonation. The HNH2 membranes properties have been evaluated using different characterization analysis. The results have shown that HNH2 membranes appear to be very promising candidates for electrochemical applications.     

Metal-supported solid oxide fuel cell operated at 400–600 °C

A metal-supported SOFC with a samarium doped ceria (SDC)/scandia-stabilized zirconia (ScSZ) bilayer electrolyte was fabricated by a combination of pulsed laser deposition (PLD) and wet ceramic processes. The cell performance and aging characteristics during operation were analyzed by both AC impedance spectroscopy and current-voltage measurements in the temperature range from 400 °C to 600 °C. The power generation characteristics of this metal-supported SOFC at low temperatures should allow for rapid start-up and help to reduce the performance deterioration seen in high temperature SOFCs due material oxidation and instability. In this paper, our early research results are presented.     

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成立于1833年的拉法基集团是全球建材领域的领先企业,其麾下的水泥、骨料与混凝土和石膏等3种业务都在全球居于领先地位,业务遍布全球80多个国家,2007年的销售额为176亿欧元,净收入19亿欧元,水泥业务板块2006至2010年的目标是新增产能4500万吨.拉法基集团1994年进入中国,成立于2005年11月的拉法基瑞安水泥有限公司目前拥有2400万吨年生产能力.