Electronic correlations in organometallic complexes

We investigate an effective model for organometallic complexes (with potential uses in optoelectronic devices) via both exact diagonalisation and the configuration interaction singles (CIS) approximation. This model captures a number of important features of organometallic complexes, notably the sensitivity of the radiative decay rate to small chemical changes. We find that for large parameter ranges the CIS approximation accurately reproduces the low energy excitations and hence the photophysical properties of the exact solution. This suggests that electronic correlations do \emph{not} play an important role in these complexes. This explains why time-dependent density functional theory works surprisingly well in these complexes.Comment: 11 pages, 6 figure

Community-acquired invasive bacterial disease in urban Gambia, 2005–2015: A hospital-based surveillance

Background. Invasive bacterial diseases cause significant disease and death in sub-Saharan Africa. Several are vaccine preventable, although the impact of new vaccines and vaccine policies on disease patterns in these communities is poorly understood owing to limited surveillance data. Methods. We conducted a hospital-based surveillance of invasive bacterial diseases in The Gambia where blood and cerebrospinal fluid (CSF) samples of hospitalized participants were processed. Three surveillance periods were defined in relation to the introduction of pneumococcal conjugate vaccines (PCVs), before (2005- 2009), during (2010–2011) and after (2012–2015) PCV introduction. We determined the prevalences of commonly isolated bacteria and compared them between the different surveillance periods. Results. A total of 14 715 blood and 1103 CSF samples were collected over 11 years; overall, 1045 clinically significant organisms were isolated from 957 patients (972 organisms [6.6%] from blood and 73 [6.6%] from CSF). The most common blood culture isolates were Streptococcus pneumoniae (24.9%), Staphylococcus aureus (22.0%), Escherichia coli (10.9%), and nontyphoidal Salmonella (10.0%). Between the pre-PCV and post-PCV eras, the prevalence of S. pneumoniae bacteremia dropped across all age groups (from 32.4% to 16.5%; odds ratio, 0.41; 95% confidence interval, .29–.58) while S. aureus increased in prevalence, becoming the most prevalent bacteria (from 16.9% to 27.2%; 1.75; 1.26–2.44). Overall, S. pneumoniae (53.4%), Neisseria meningitidis (13.7%), and Haemophilus influenzae (12.3%) were the predominant isolates from CSF. Antimicrobial resistance to common antibiotics was low. Conclusions. Our findings demonstrate that surveillance data on the predominant pathogens associated with invasive disease is necessary to inform vaccine priorities and appropriate management of patients

Order Profiles Of Host Decyl Sulfate And Decylammonium Chains And Guest Carboxylic Acids And Carboxylates In Allgned Type Ii Dm Lyomesophases

Lyotropic liquid crystals type II (DM) have been synthesized from sodium decyl sulfate, decanol, water, and sodium sulfate with low concentrations of lauric, palmitic, and stearic acids and their conjugate anions. A wide variation of specifically deuterated decyl sulfate chains has been incorporated in low concentration as well as perdeuterated decyl sulfate, carboxylic acids, and their anions. Degrees of order profiles have been extracted from the study of deuterium quadrupole splittings in the corresponding NMR spectra of aligned mesophases. The ratios of segmental order along the C-D bonds for host decyl sulfate chains are independent of water content (within the region of the DM phase), a temperature variation of 3 °C, and the presence of small quantities of the guest amphiphiles. The invariance of the kink/jog motions in the decyl sulfate chain as the water content is varied has been interpreted in terms of the invariance in internal packing of host chains inside the disk micelle as these entities are diluted with more interstitial water. The decrease in absolute degrees of order of the decyl sulfate segments as water is added can be explained by increases in the amplitude of micelle motion because the water layer is increased in thickness and perhaps also because the mean disk diameter may decrease with added water. The guest amphiphile chains do not conform in length to the half bilayer thickness of the disk micelle. Several types of behavior have been noted: (a) The guest head group anchoring at the interface determines the form of the order profile of the guest chain to a very large extent within the half bilayer distance; i.e., the form of the order profiles near the anchored end depends on the head group and not on the chain length for long chains, (b) The guests are uniformly of higher order in the first segments at the impurity site than the host segments which form the solvent bilayer. (c) In the case of carboxylic acid guests, the degree of order profile in the region of high probability for single gauche rotations follows very closely that of the solvent SDS/decanol bilayer. (d) The degree of order profiles of carboxylate guests, on the other hand, are quite distinct from the host segments. A higher order of the guest chains persists well beyond the half bilayer distance, (e) A third situation arises for carboxylic acid guests in a decylammonium chloride type II DM mesophase. In this case the fall in order of the guest chains occurs well wiithin the plateau region of the host chains, (f) The excess chain lengths of palmitic, myristic, and stearic acids and anions participate in the disordered region at the center of the disk bilayer structure having low and steadily decreasing order. Nevertheless, the ratio of CD 2 to CD 3 splitting the nonpolar end of the chain falls close to a theoretical ratio of 3 for a rigid chain for the anion guests. © 1980 American Chemical Society.84666267

Molecular changes associated with hippocampal long-lasting depression induced by the serine protease subtilisin-A

The serine protease subtilisin-A (SubA) induces a form of long-term depression (LTD) of synaptic transmission in the rat hippocampus, and molecular changes associated with SubA-induced LTD (SubA-LTD) were explored by using recordings of evoked postsynaptic potentials and immunoblotting. SubA-LTD was prevented by a selective inhibitor of SubA proteolysis, but the same inhibitor did not affect LTD induced by electrical stimulation or activation of metabotropic glutamate receptors. SubA-LTD was reduced by the protein kinase inhibitors genistein and lavendustin A, although not by inhibitors of p38 mitogen-activated protein kinase, glycogen synthase kinase-3, or protein phosphatases. It was also reduced by (<i>RS</i>)-α-methyl-4-carboxyphenylglycine, a broad-spectrum antagonist at metabotropic glutamate receptors. Inhibition of the Rho kinase enzyme Rho-associated coiled-coil kinase reduced SubA-LTD, although inhibitors of the RhoGTPase-activating enzymes farnesyl transferase and geranylgeranyl transferase did not. In addition, a late phase of SubA-LTD was dependent on new protein synthesis. There was a small, non-significant difference in SubA-LTD between wild-type and RhoB<sup>-/-</sup> mice. Marked decreases were seen in the levels of Unc-5H3, a protein that is intimately involved in the development and plasticity of glutamatergic synapses. Smaller changes were noted, at higher concentrations of SubA, in Unc-5H1, vesicle-associated membrane protein-1 (synaptobrevin), and actin, with no changes in the levels of synaptophysin, synaptotagmin, RhoA, or RhoB. None of these changes was associated with LTD induced electrically or by the metabotropic glutamate receptor agonist (<i>RS</i>)-3,5-dihydroxyphenylglycine. These results indicate that SubA induces molecular changes that overlap with other forms of LTD, but that the overall molecular profile of SubA-LTD is quite differen