Palladocarbosilane dendrons in supercritical carbon dioxide. Catalytic behaviour in the asymmetric hydrovinylation of styrene

The palladocarbosilane dendrons 1 and 2, containing the P-stereogenic phosphine fragment at the focal point are soluble in supercritical CO₂ medium and capable to catalyze the asymmetric hydrovinylation of styrene with good activity and enantiomeric excesses.     

Materials and Manufacturing Methods for EWOD Devices: Current Status and Sustainability Challenges

Electrowetting-on-dielectric (EWOD) devices have proven to be effective tools for precise microfluidic manipulation or in liquid lenses that surpass conventional solid lenses in versatility. However, the fabrication of these devices presents many challenges, such as their scalability or the growing concern on their environmental impact due to materials used in their fabrication. This review provides a comprehensive analysis of the materials currently used in the fabrication of EWOD devices and the characteristics they must meet. In addition, a discussion of future challenges in the fabrication of EWOD devices is presented, in particular the environmental problems presented by some of the materials currently in use.     

Analysis of reactive power strategies in HVDC‐connected wind power plant clusters

Offshore wind power plants (WPPs) built near each other but far from shore usually connect to the main grid by a common high‐voltage DC (HVDC) transmission system. In the resulting decoupled offshore grid, the wind turbine converters and the high‐voltage DC voltage‐source converter share the ability to inject or absorb reactive power. The overall reactive power control dispatch influences the power flows in the grid and hence the associated power losses. This paper evaluates the respective power losses in HVDC‐connected WPP clusters when applying 5 different reactive power control strategies. The case study is made for a 1.2‐GW–rated cluster comprising 3 WPP and is implemented in a combined load flow and converter loss model. A large set of feasible operating points for the system is analyzed for each strategy. The results show that a selection of simulations with equal wind speeds is sufficient for the annual energy production comparison. It is found that the continuous operation of the WPPs with unity power factor has a superior performance with low communication requirements compared with the other conventional strategies. The optimization‐based strategy, which is developed in this article, allows a further reduction of losses mainly because of the higher offshore grid voltage level imposed by the high‐voltage DC voltage‐source converter. Reactive power control in HVDC‐connected WPP clusters change significantly the overall power losses of the system, which depend rather on the total sum of the injected active power than on the variance of wind speeds inside the cluster.     

Cassava starch snack formulation using functional shell fish by‐products: mechanical,sorption and geometric properties

Utilisation of by‐products of the shrimp industry, namely shrimp head protein and chitosan, could lead to a functional snack with substantial market in Asia. Produced on a cassava starch base this would lead to a product with shrimp flavour and chitosan's lipid adsorption capacity. The characteristics of such a mixture with 82% deacetylated chitosan and salt was investigated by Rapid Visco Analyser and instrumental Texture Profile Analyser using the Doehlert Uniform Shell experimental design. Polynomial models explained more than 88% of variability of responses. A significant effect of salt, shrimp head proteins and chitosan was observed on cassava starch gelling characteristics. A corresponding heat and shear stress resistance ability was observed while there was a reduction in its specific swelling power. Snacks prepared in the form of chips and extruded product confirmed their good potential for added value to snack foods in respect of their 90–94% linear expansion ratio, up to 1.1 kg maximum breaking force and up to 4.5 radial expansion ratio. Adsorption isotherm of extrudates had a maximum water content target of 115 g kg^?1 dry matter at 25 °C for a later formulation and extrusion optimisation, in order to guarantee consumer texture acceptability. Corresponding shelf‐lives of extrudates were calculated at three storage conditions. Copyright © 2005 Society of Chemical Industry     

Effects of long-term pH elevation on the sulfate-reducing and methanogenic activities of anaerobic sewer biofilms

The dosage of alkali is often applied by the wastewater industry to reduce the transfer of hydrogen sulfide from wastewater to the sewer atmosphere. In this paper the activities of Sulfate Reducing Bacteria (SRB) and Methanogenic Archaea (MA) under elevated pH conditions (8.6 and 9.0) were evaluated in a laboratory scale anaerobic sewer reactor. Compared to those in a control reactor without pH control (pH 7.6 ± 0.1), the SRB activity was reduced by 30% and 50%, respectively, at pH 8.6 and pH 9.0. When normal pH was resumed, it took approximately 1 month for the SRB activity to fully recover. Methanogenic activities developed in the control reactor in 3 months after the reactor start-up, while no significant methanogenic activities were detected in the experimental reactor until normal pH was resumed. The results suggest that elevated pH at 8.6-9.0 suppressed the growth of methanogens. These experimental results clearly showed that, in addition to its well-known effect of reducing H₂S transfer from the liquid to the gas phase, pH elevation considerably reduces sulfide and methane production by anaerobic sewer biofilms. These findings are significant for the optimal use of alkali addition to sewers for the control of H₂S and CH₄ emissions. A model-based study showed that, by adding the alkali at the beginning rather than towards the end of a rising main, substantial savings in chemicals can be achieved while achieving the same level of sulfide emission control, and complete methane emission control.     

A floodplain spring: An ecotone between surface water and groundwater

Ecotones may be viewed as boundaries separating adjacent resource patches. They are dynamic components of the aquatic landscape and in the alluvial floodplain they occur as both diffuse and concentrated zones between surface and groundwater environments. This study is focused on a floodplain spring whose water supplies a backwater of the upper Rh6ne River alluvial floodplain (Iles Nouvelles). This paper analyses the community structure on both sides of the physical boundary separating the two ecosystems in relation to hydrological characteristics. The contact between two different environments (surface water and water-saturated sediment) creates a physical discontinuity which is of great importance for the distribution of aquatic fauna. Two types of organization are described: (1) within the sediment body there are mixed communities (epigean and hypogean) which can move with hydrological variations (biological ecotone) and (2) within the surface-water body there is a typical epigean fauna which displays a ‘border effect’. The ecological implications of the various patterns of biological responses are discussed as well as the regulatory aspect of the ecotone which minimizes the washout of hypogean fauna towards the surface ecosystem.     

In vivo quantification of response to treatment in patients with multiple myeloma by <Superscript>1</Superscript>H magnetic resonance spectroscopy of bone marrow

Object Magnetic resonance imaging (MRI) is the gold standard non-invasive technique to detect malignant disease in the bone marrow. Proton magnetic resonance spectroscopy (MRS) can be performed as a quick adjunct to routine spinal MRI. We performed proton MRS to patients with multiple myeloma (MM) at diagnosis and after treatment to investigate the possible correlation of MRS data with response to therapy. Patients and methods Twenty-one patients with newly diagnosed MM underwent combined MRI/MRS explorations of a transverse center section in the fifth lumbar vertebral body. MRS was acquired with STEAM and 40 ms TE. Areas of unsuppressed water and lipid resonances were used to calculate the lipid-to-water ratio (LWR). Results No association was detected between initial LWRs and the clinical characteristics of patients. Post treatment MRS was available in 16 patients of whom 11 (69%) presented an LWR increase, this included all complete responders (8/8, 100%, P = 0.012). A post-treatment LWR value equal to or larger than one is proposed as a non-invasive marker of complete response to treatment. Conclusion Only patients responding to treatment presented a significant increase in bone marrow LWR after therapy. MRS may provide an adequate quantification of response to chemotherapy in patients with MM.