The application of calcined natural dolomitic rock as a solid base catalyst in triglyceride transesterification for biodiesel synthesis

Natural dolomitic rock has been investigated in the transesterification of C and C triglycerides and olive oil with a view to determining its viability as a solid base catalyst for use in biodiesel synthesis. XRD reveals that the dolomitic rock comprised 77% dolomite and 23% magnesian calcite. The generation of basic sites requires calcination at 900 °C, which increases the surface area and transforms the mineral into MgO nanocrystallites dispersed over CaO particles. Calcined dolomitic rock exhibits high activity towards the liquid phase transesterification of glyceryl tributyrate and trioctanoate, and even olive oil, with methanol for biodiesel production. © The Royal Society of Chemistry 2008.

Enhanced selective aerobic alcohol oxidation through nanoengineered catalyst supports

The selective conversion of alcohols to their carbonyl derivatives is a critical step towards a sustainable chemical industry. Heterogeneous Pd catalysts represent some of the most active systems known, even so further studies into the active species and role of support are required. Through controlling support mesostructure, using non-interconnected SBA-15 and interlinked SBA-16 and KIT-6, we have evaluated the role of pore architecture on supported Pd nanoparticles and their subsequent activity for liquid phase aerobic allylic alcohol selective oxidation.[1,2] These synthesised silica supports exhibit high surface areas (>800 m2g-1), and similar mesopore diameters (3.5 to 5 nm), but differ in their pore connectivity and arrangement; p6mm (SBA-15), I3mm (SBA-16) and I3ad (KIT-6). When evaluated alongside commercial non-mesoporous silica (200 m2 g-1) they promote enhanced Pd dispersion with interpenetrating assemblies providing further elevation. Macropore introduction into SBA-15, producing a hierarchical macro-mesoporous silica (MM-SBA-15), allows control over mesopore length and accessibility which escalates Pd distribution to levels akin to KIT-6 and SBA-16. Controlling dispersion, and likewise nanoparticle size, is thus facilitated through the choice of support and additionally Pd loading, with cluster sizes spanning 3.2 to 0.8 nm. X-ray spectroscopies indicate nanoparticles are PdO terminated with the oxide content a function of dispersion. Kinetic studies allude to surface PdO being the active site responsible, with a constant TOF observed, independent of loading and support. This confirms activity is governed by PdO density, whilst also overruling internal mass diffusion constraints. MM-SBA-15 facilitates superior activity and TOFs for long chain acyclic terpene alcohols due to reduced internal mass transport constraints.

Hierarchically ordered nanoporous Pd/SBA-15 catalyst for the aerobic selective oxidation of sterically challenging allylic alcohols

The utility of a hierarchically ordered nanoporous SBA-15 architecture, comprising 270 nm macropores and 5 nm mesopores (MM-SBA-15), for the catalytic aerobic selective oxidation of sterically challenging allylic alcohols is shown. Detailed bulk and surface characterization reveals that incorporation of complementary macropores into mesoporous SBA-15 enhances the dispersion of sub 2 nm Pd nanoparticles and thus their degree of surface oxidation. Kinetic profiling reveals a relationship between nanoparticle dispersion and oxidation rate, identifying surface PdO as the catalytically active phase. Hierarchical nanoporous Pd/MM-SBA-15 outperforms mesoporous analogues in allylic alcohol selective oxidation by (i) stabilizing PdO nanoparticles and (ii) dramatically improving in-pore diffusion and access to active sites by sesquiterpenoid substrates such as farnesol and phytol. © 2013 American Chemical Society.

Background synaptic activity in rat entorhinal cortex shows a progressively greater dominance of inhibition over excitation from deep to superficial layers

The entorhinal cortex (EC) controls hippocampal input and output, playing major roles in memory and spatial navigation. Different layers of the EC subserve different functions and a number of studies have compared properties of neurones across layers. We have studied synaptic inhibition and excitation in EC neurones, and we have previously compared spontaneous synaptic release of glutamate and GABA using patch clamp recordings of synaptic currents in principal neurones of layers II (L2) and V (L5). Here, we add comparative studies in layer III (L3). Such studies essentially look at neuronal activity from a presynaptic viewpoint. To correlate this with the postsynaptic consequences of spontaneous transmitter release, we have determined global postsynaptic conductances mediated by the two transmitters, using a method to estimate conductances from membrane potential fluctuations. We have previously presented some of this data for L3 and now extend to L2 and L5. Inhibition dominates excitation in all layers but the ratio follows a clear rank order (highest to lowest) of L2>L3>L5. The variance of the background conductances was markedly higher for excitation and inhibition in L2 compared to L3 or L5. We also show that induction of synchronized network epileptiform activity by blockade of GABA inhibition reveals a relative reluctance of L2 to participate in such activity. This was associated with maintenance of a dominant background inhibition in L2, whereas in L3 and L5 the absolute level of inhibition fell below that of excitation, coincident with the appearance of synchronized discharges. Further experiments identified potential roles for competition for bicuculline by ambient GABA at the GABAA receptor, and strychnine-sensitive glycine receptors in residual inhibition in L2. We discuss our results in terms of control of excitability in neuronal subpopulations of EC neurones and what these may suggest for their functional roles. © 2014 Greenhill et al.

Carbon nanotube-supported metal catalysts for NOx reduction using hydrocarbon reductants. Part 1:catalyst preparation, characterization and NOx reduction characteristics

A dual catalyst system for the Selective Catalytic Reduction of NOx with hydrocarbons (HC-SCR), including distinct low and high temperature formulations, is proposed as a means to abate NOx emissions from diesel engines. Given that satisfactory high temperature HC-SCR catalysts are already available, this work focuses on the development of an improved low temperature formulation. Pt supported on multiwalled carbon nantubes (MWCNTs) was found to exhibit superior NOx reduction activity in comparison with Pt/Al2O3, while the MWCNT support displayed a higher resistance to oxidation than activated carbon. Refluxing the MWCNT support in a 1:1 mixture of H2SO4 and HNO3 prior to the metal deposition step proved to be beneficial for the metal dispersion and the NOx reduction performance of the resulting catalysts. This support effect is ascribed to the increased Brønsted acidity of the acid-treated MWCNTs, which in turn enhances the partial oxidation of the hydrocarbon reductant. Further improvements in the HC-SCR performance of MWCNT-based formulations were achieved using a 3:1 Pt–Rh alloy as the supported phase.

Surface X-ray studies of catalytic clean technologies

The rational design of new heterogeneous catalysts for clean chemical technologies can be accelerated by molecular level insight into surface chemical processes. In situ methodologies, able to provide time-resolved and/or pressure dependent information on the evolution of reacting adsorbed layers over catalytically relevant surfaces, are therefore of especial interest. Here we discuss recent applications of surface X-ray techniques to surface-catalysed oxidations, (de)hydrogenations, C-C coupling, dehalogenation and associated catalyst restructuring, and explore how these may help to shape future sustainable chemistry. © 2010 The Royal Society of Chemistry.

A polyoxometallate-tethered Ru complex as a catalyst in solventless phenyl acetylene oligomerisation

A novel compound comprising a Ru–tethered polyoxometallate Keggin anion of formula [HNEt3]+[(Ru{η5-C5H5}{PPh3}2)2(PW12O40)]− has been synthesised that shows high activity and selectivity in alkyne oligomerisation. In situ IR binding studies using CO confirmed the accessibility of the Ru centre for catalysis. Phenyl acetylene was successfully dimerised under a heterogeneous catalytic regime. Selectivity towards the (E)-enyne, not found in the homogeneous Ru(η5-C5H5)(PPh3)2Cl analogue, was achieved while retaining high a turnover frequency of 225 h−1.

Amine-functionalised hexagonal mesoporous silica as support for copper(II) acetylacetonate catalyst

Copper(II) acetylacetonate was anchored onto a hexagonal mesoporous silica (HMS) material using a two-step procedure: (i) functionalisation of the surface hydroxy groups with (3-aminopropyl)triethoxysilane (AMPTSi) and then (ii) anchoring of the copper(II) complex through Schiff condensation with free amine groups, using two different metal complex loadings. Upon the first step, nitrogen elemental analysis, XPS and DRIFT showed the presence of amine groups on the surface of the HMS material, and porosimetry indicated that the structure of the mesoporous material remained unchanged, although a slight decrease in surface area was observed. Atomic absorption, XPS and DRIFT showed that copper(II) acetylacetonate was anchored onto the amine-functionalised HMS by Schiff condensation between the free amine groups and the carbonyl groups of the copper(II) complex; using EPR an NO3 coordination sphere was proposed for the anchored copper(II) complex. The new [Cu(acac)2]-AMPTSi/HMS materials were tested in the aziridination of styrene at room temperature, using PhI=NTs as nitrogen source and acetonitrile as solvent. The styrene conversion and total TON of the heterogeneous phase reaction are higher than those of the same reaction catalysed in homogeneous phase by [Cu(acac)2]; nevertheless, the initial activity decreases and the reaction time increases due to substrate and product diffusion limitations. The heterogeneous catalyst showed a successive slight decrease in catalytic activity when reused for two more times. © Wiley-VCH Verlag GmbH & Co. KGaA, 2006.

Personal values as a catalyst for corporate social entrepreneurship

The literature acknowledges a distinction between immoral, amoral and moral management. This paper makes a case for the employee (at any level) as a moral agent, even though the paper begins by highlighting a body of evidence which suggests that individual moral agency is sacrificed at work and is compromised in deference to other pressures. This leads to a discussion about the notion of discretion and an examination of a separate, contrary body of literature which indicates that some individuals in corporations may use their discretion to behave in a socially entrepreneurial manner. My underlying assumption is that CSR isn’t solely driven by economics and that it may also be championed as a result of a personal morality, inspired by employees’ own socially oriented personal values. A conceptual framework is put forward and it is suggested that individuals may be categorized as Active or Frustrated Corporate Social Entrepreneurs; Conformists or Apathetics, distinguished by their individualistic or collectivist personal values. In a discussion of the nature of values, this paper highlights how values may act as drivers of our behavior and pays particular attention to the values of the entrepreneur, thereby linking the existing debate on moral agency with the field of corporate social responsibility.

Propene combustion over a model Pt/Al2O3/NiAl{110} catalyst

The genesis of a catalytically active model Pt/Al2O3/NiAl{110} oxidation catalyst is described. An ultrathin, crystalline γ-Al2O3 film was prepared via direct oxidation of a NiAl{110} single-crystal substrate. The room-temperature deposition of Pt clusters over the γ-Al2O3 film was characterised by LEED, AES and CO titration and follows a Stranski–Krastanov growth mode. Surface sulfation was attempted via SO2/O2 adsorption and thermal processing over bare and Pt promoted Al2O3/NiAl{110}. Platinum greatly enhances the saturation SOx coverage over that of bare alumina. Over clean Pt/γ-Al2O3 surfaces some adsorbed propene desorbs molecularly [similar]250 K while the remainder decomposes liberating hydrogen. Coadsorbed oxygen or sulfate promote propene combustion, with adsorbed sulfoxy species the most efficient oxidant. The chemistry of these alumina-supported Pt clusters shows a general evolution from small polycrystalline clusters to larger clusters with properties akin to low-index, Pt single-crystal surfaces.

Almost Separable Data Aggregation by Layers of Formal Neurons

Information extraction or knowledge discovery from large data sets should be linked to data aggregation process. Data aggregation process can result in a new data representation with decreased number of objects of a given set. A deterministic approach to separable data aggregation means a lesser number of objects without mixing of objects from different categories. A statistical approach is less restrictive and allows for almost separable data aggregation with a low level of mixing of objects from different categories. Layers of formal neurons can be designed for the purpose of data aggregation both in the case of deterministic and statistical approach. The proposed designing method is based on minimization of the of the convex and piecewise linear (CPL) criterion functions.

Simultaneous en-face imaging of two layers in human retina by low-coherence reflectometry

We show that with a fiberized multiple Michelson-interferometer-type configuration, transverse images from several layers in the human eye can be simultaneously obtained. We demonstrate the principle by producing simultaneous 100×100 pixel en-face images of a 4 mm×4 mm region on a postmortem retina for two depth positions 250 µm apart.

Novel Ni-Mg-Al-Ca catalyst for enhanced hydrogen production for the pyrolysis-gasification of a biomass/plastic mixture

A Ni-Mg-Al-Ca catalyst was prepared by a co-precipitation method for hydrogen production from polymeric materials. The prepared catalyst was designed for both the steam cracking of hydrocarbons and for the in situ absorption of CO2 via enhancement of the water-gas shift reaction. The influence of Ca content in the catalyst and catalyst calcination temperature in relation to the pyrolysis-gasification of a wood sawdust/polypropylene mixture was investigated. The highest hydrogen yield of 39.6molH2/g Ni with H2/CO ratio of 1.90 was obtained in the presence of the Ca containing catalyst of molar ratio Ni:Mg:Al:Ca=1:1:1:4, calcined at 500°C. In addition, thermogravimetric and morphology analyses of the reacted catalysts revealed that Ca introduction into the Ni-Mg-Al catalyst prevented the deposition of filamentous carbon on the catalyst surface. Furthermore, all metals were well dispersed in the catalyst after the pyrolysis-gasification process with 20-30nm of NiO sized particles observed after the gasification without significant aggregation.

Precompetitive data sharing as a catalyst to address unmet needs in Parkinson's disease

Parkinson's disease is a complex heterogeneous disorder with urgent need for disease-modifying therapies. Progress in successful therapeutic approaches for PD will require an unprecedented level of collaboration. At a workshop hosted by Parkinson's UK and co-organized by Critical Path Institute's (C-Path) Coalition Against Major Diseases (CAMD) Consortiums, investigators from industry, academia, government and regulatory agencies agreed on the need for sharing of data to enable future success. Government agencies included EMA, FDA, NINDS/NIH and IMI (Innovative Medicines Initiative). Emerging discoveries in new biomarkers and genetic endophenotypes are contributing to our understanding of the underlying pathophysiology of PD. In parallel there is growing recognition that early intervention will be key for successful treatments aimed at disease modification. At present, there is a lack of a comprehensive understanding of disease progression and the many factors that contribute to disease progression heterogeneity. Novel therapeutic targets and trial designs that incorporate existing and new biomarkers to evaluate drug effects independently and in combination are required. The integration of robust clinical data sets is viewed as a powerful approach to hasten medical discovery and therapies, as is being realized across diverse disease conditions employing big data analytics for healthcare. The application of lessons learned from parallel efforts is critical to identify barriers and enable a viable path forward. A roadmap is presented for a regulatory, academic, industry and advocacy driven integrated initiative that aims to facilitate and streamline new drug trials and registrations in Parkinson's disease.