Polarized aluminum K-edge X-ray absorption near edge structure (XANES) spectroscopy and first-principles calculations were used to probe electronic structure in a series of (BDI)Al, (BDI)AlX2, and ...(BDI)AlR2 coordination compounds (X = F, Cl, I; R = H, Me; BDI = 2,6-diisopropylphenyl-β-diketiminate). Spectral interpretations were guided by examination of the calculated transition energies and polarization-dependent oscillator strengths, which agreed well with the XANES spectroscopy measurements. Pre-edge features were assigned to transitions associated with the Al 3p orbitals involved in metal–ligand bonding. Qualitative trends in Al 1s core energy and valence orbital occupation were established through a systematic comparison of excited states derived from Al 3p orbitals with similar symmetries in a molecular orbital framework. These trends suggested that the higher transition energies observed for (BDI)AlX2 systems with more electronegative X1– ligands could be ascribed to a decrease in electron density around the aluminum atom, which causes an increase in the attractive potential of the Al nucleus and concomitant increase in the binding energy of the Al 1s core orbitals. For (BDI)Al and (BDI)AlH2 the experimental Al K-edge XANES spectra and spectra calculated using the eXcited electron and Core–Hole (XCH) approach had nearly identical energies for transitions to final state orbitals of similar composition and symmetry. These results implied that the charge distributions about the aluminum atoms in (BDI)Al and (BDI)AlH2 are similar relative to the (BDI)AlX2 and (BDI)AlMe2 compounds, despite having different formal oxidation states of +1 and +3, respectively. However, (BDI)Al was unique in that it exhibited a low-energy feature that was attributed to transitions into a low-lying p-orbital of b1 symmetry that is localized on Al and orthogonal to the (BDI)Al plane. The presence of this low-energy unoccupied molecular orbital on electron-rich (BDI)Al distinguishes its valence electronic structure from that of the formally trivalent compounds (BDI)AlX2 and (BDI)AlR2. The work shows that Al K-edge XANES spectroscopy can be used to provide valuable insight into electronic structure and reactivity relationships for main-group coordination compounds.
A chronic subdural haematoma (cSDH) is a collection of altered blood products between the dura and brain resulting in a slowly evolving neurological deficit. It is increasingly common and, in high ...income countries, affects an older, multimorbid population. With changing demographics improving the care of this cohort is of increasing importance.
We convened a cross-disciplinary working group (the 'Improving Care in Elderly Neurosurgery Initiative') in October 2020. This comprised experts in neurosurgical care and a range of perioperative stakeholders. An Implementation Science framework was used to structure discussions around the challenges of cSDH care within the United Kingdom. The outcomes of these discussions were recorded and summarised, before being circulated to all attendees for comment and refinement.
The working group identified four key requirements for improving cSDH care: (1) data, audit, and natural history; (2) evidence-based guidelines and pathways; (3) shared decision-making; and (4) an overarching quality improvement strategy. Frequent transfers between care providers were identified as impacting on both perioperative care and presenting a barrier to effective data collection and teamworking. Improvement initiatives must be cognizant of the complex, system-wide nature of the problem, and may require a combination of targeted trials at points of clinical equipoise (such as anesthetic technique or anticoagulant management), evidence-based guideline development, and a cycle of knowledge acquisition and implementation.
The care of cSDH is a growing clinical problem. Lessons may be learned from the standardised pathways of care such as those as used in hip fracture and stroke. A defined care pathway for cSDH, encompassing perioperative care and rehabilitation, could plausibly improve patient outcomes but work remains to tailor such a pathway to cSDH care. The development of such a pathway at a national level should be a priority, and the focus of future work.
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DOBA, IJS, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
This landmark scientific reference for scientists, researchers, and students of marine biology tackles the monumental task of taking a complete biodiversity inventory of the Gulf of Mexico with full ...biotic and biogeographic information. Presenting a comprehensive summary of knowledge of Gulf biota through 2004, the book includes seventy-seven chapters, which list more than fifteen thousand species in thirty-eight phyla or divisions and were written by 138 authors from seventy-one institutions in fourteen countries.
Measurements of adsorption isotherms of a series of thirteen mono- and di-phosphonic acids have shown that these bind strongly to the surface of high surface area aluminium trihydroxide. The ...incorporation of such phosphonates into a suspension of aluminium flake in an aqueous medium, modelling the continuous phase of a water-based paint, greatly suppresses the evolution of hydrogen. Whilst strong binding of the phosphonate to aluminium oxides is an essential criterion for good passivation, other factors such as the hydrophobicity of the ligand are also important in suppressing hydrogen-evolution.
The fauna of seagrass-covered mud banks in Florida Bay, documented in the mid 1980s prior to recent seagrass die-off, phytoplankton blooms, and other ecosystem changes, was reexamined in the mid ...1990s for faunal changes that might be associated with environmental perturbations. During both decades, decapod crustaceans and fishes were collected with 1- m2 throw traps from seagrass beds at six sites that differ in the amount of freshwater and/or marine influence and in seagrass community metrics. The most common faunal changes were declines in seagrass-canopy-dwelling forms and increases in benthic forms. At three sites with relatively lush seagrass meadows, above-ground seagrass standing crop declined and abundance of the benthic predatory fish Opsanus beta increased. The degree of faunal change among these sites appeared to be related either to salinity variability or to the degree of exposure to the ecosystem changes that have taken place in Florida Bay. At two sites with poorly developed seagrass meadows, seagrass standing crop and canopy height did not change significantly between decades, but there was an increase in shoot density and total leaf area. The animal communities at these sites were characterized by significant increases in the abundance of benthic crustaceans. At the site on the edge of Rankin Lake, the basin where seagrass die-off was first observed in Florida Bay during 1987, seagrass standing crop, canopy height, shoot density, and leaf area declined significantly between decades, but species richness of both crustaceans and fishes increased. The abundance of canopy-dwelling crustaceans and fishes declined markedly at this site, whereas the abundance of benthic forms less dependent on seagrass cover generally increased. In retrospect, we believe the fauna at this site during the 1980s, characterized by high productivity but few species, was already showing signs of the stresses that led to the seagrass die-off that began in 1987.
Simple azo-dyes carrying phosphonic acid and arsonic acid substituents such as 4-(4-hydroxyphenyl azo)phenylphosphonic acid (5) and 4-(4-hydroxyphenylazo)phenylarsonic acid (6) bind more strongly to ...high surface area oxides such as aluminium trihydroxide and goethite than their carboxylic and sulfonic acid analogues and the phosphonate-functionalized dyes have been shown to have greater humidity fastness when printed onto commercial alumina-coated papers. Adsorption isotherm measurements provide evidence for the formation of ternary dye/cyclodextrin/surface complexes. Dyes which form such ternary complexes show higher light fastness when printed onto alumina coated papers in an ink formulation containing alpha-cyclodextrin.
This landmark scientific reference for scientists, researchers, and students of marine biology tackles the monumental task of taking a complete biodiversity inventory of the Gulf of Mexico with full ...biotic and biogeographic information. Presenting a comprehensive summary of knowledge of Gulf biota through 2004, the book includes seventy-seven chapters, which list more than fifteen thousand species in thirty-eight phyla or divisions and were written by 138 authors from seventy-one institutions in fourteen countries. This first volume of Gulf of Mexico Origin, Waters, and Biota, a multivolumed set edited by John W. Tunnell Jr., Darryl L. Felder, and Sylvia A. Earle, provides information on each species' habitat, biology, and geographic range, along with full references and a narrative introduction to the group, which opens each chapter.
Phosphonate-functionalised dyes have been shown to bind strongly to aluminium oxides and to form stable 1:1 complexes with cyclodextrins at the surface.
A common neurosurgical condition, chronic subdural haematoma (cSDH) typically affects older people with other underlying health conditions. The care of this potentially vulnerable cohort is often, ...however, fragmented and suboptimal. In other complex conditions, multidisciplinary guidelines have transformed patient experience and outcomes, but no such framework exists for cSDH. This paper outlines a protocol to develop the first comprehensive multidisciplinary guideline from diagnosis to long-term recovery with cSDH.
The project will be guided by a steering group of key stakeholders and professional organisations and will feature patient and public involvement. Multidisciplinary thematic working groups will examine key aspects of care to formulate appropriate, patient-centered research questions, targeted with evidence review using the GRADE framework. The working groups will then formulate draft clinical recommendations to be used in a modified Delphi process to build consensus on guideline contents.
We present a protocol for the development of a multidisciplinary guideline to inform the care of patients with a cSDH, developed by cross-disciplinary working groups and arrived at through a consensus-building process, including a modified online Delphi.
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