Reaction pathways leading to the formation of naphthalene by the addition of vinylacetylene to phenyl were examined using density functional theory B3-LYP functionals with the standard triple-zeta ...basis set, 6-311G(d,p). The chemically activated reaction dynamics were examined employing time-dependent solution of master equations. The addition of phenyl to the triple bond of vinylacetylene was computed to be relatively slow, due to a substantial energy barrier of the intermediate rotation about the double bond. Addition of phenyl to the other end of a vinylacetylene molecule produced equally low rate constants. The most promising pathway appeared to be a two-step reaction sequence via the formation of phenyl-C
4H
3 molecules. The reaction rate evaluated for this pathway was very close to the value tested in prior flame simulations that demonstrated a dominant character of such a step for naphthalene formation. This indicates that the formation of naphthalene from phenyl and vinylacetylene may play a significant role in flame modeling of aromatic growth, and that the more favorable mechanism of the reaction may be a two-step sequence via the formation of a stable molecular intermediate rather than a “single” chemically activated path. The time-dependent solution of master equations revealed that at flame conditions typical of aromatic growth, the reaction system does not attain a steady state on a timescale of 1 ms, suggesting that dynamics of energy redistribution in such “elementary” reaction systems may need to be treated with inclusion of bimolecular reactions between energized adducts and gaseous partners.
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Screening for vancomycin-resistant Enterococcus (VRE) has not been universally implemented within the Department of Veterans Affairs (VA). A prospective study was conducted to identify the admission ...prevalence rate of VRE in patients admitted to the intensive care unit in 2 VA facilities. Significant regional differences were found between the 2 facilities. Further studies are needed to account for regional differences in VRE admission prevalence, to optimize infection control interventions.
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Abstract Early recognition of and response to changes in patients’ conditions are a National Patient Safety Goal. Rapid Response Teams (RRTs) are one safety strategy aimed at early recognition of ...signs and symptoms of clinical deterioration and reduction in rates of cardiopulmonary arrest and death in hospitalized patients. Mock codes and RRTs are another strategy for improving outcomes.The Corporal Michael J. Crescenz VA Medical Center(CMCVAMC) used data from the American Heart Association National Registry of Cardio-Pulmonary Resuscitation to create an interprofessional, collaborative program using simulation. The program included: review of emergency responses and hands-on sessions with crash cart equipment, airway management, and BLS skills, followed by a mock RRT and Code with debriefing. Participants in this quality improvement initiative were nurses, physicians, anesthetists, pharmacists, and respiratory therapists. They evaluated the simulation as a positive learning experience. Staff and patient outcomes were improved after the program. The program engaged staff and promoted interprofessional collaboration that may ultimately improve the quality of patient care.
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Abstract Background The ability to drive is a core function supporting independent living. Traumatic brain injury (TBI) may impair driving capacity in numerous ways. Previous research has documented ...that individuals with TBI have more driving-related problems than other people and has identified predictors of driving status or capacity, mostly among civilians. But no research has examined the implications of driving limitations for the well-being of individuals with TBI. Objective To examine the association between self-reported difficulty in driving with important domains of psychological well-being in veterans with TBI, adjusting for PTSD and years since most recent TBI. Design Cross-sectional. Setting Veterans’ homes Participants 61 veterans of the Global Wars on Terror diagnosed with TBI, all outpatient at a VA medical center rehabilitation service Methods Home interviews as a baseline assessment for a larger randomized controlled trial Main Outcome Measures : Community reintegration (extent of social participation), depressive symptomatology, role limitations due to physical health problems and those due to emotional problems. Self-rated competence in driving was the predictor and sociodemographic characteristics, PTSD diagnosis, TBI severity, and time since most recent TBI were covariates. Results Self-rated driving difficulty was associated with decreased community reintegration (β= .280, p =.028), greater depressive symptomatology (β= -. 402, p <.001), and greater role limitations due to physical problems (β= -.312, p =.011) and to emotional problems (β= -.324, p =.006), after adjusting for PTSD and other variables. Discussion The self-reported ability to drive seems to be central to psychological well-being in veterans with TBI, showing clear associations with depression, community reintegration, and health-related role limitations. These associations cannot be attributed to comorbid PTSD. Conclusion Rehabilitation specialists should view driving difficulty as a risk factor for poor psychosocial outcomes in veterans with TBI and seek ways to compensate for the veteran’s loss of driving if it is no longer advisable.
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25.
Tetramethylene: A CASPT2 study Moriarty, Nigel W; Lindh, Roland; Karlström, Gunnar
Chemical physics letters,
06/1998, Volume:
289, Issue:
5-6
Journal Article
Peer reviewed
The potential energy surface (PES) of the 1,4-tetramethylene biradical has been reinvestigated at the complete-active-space self-consistent field (CASSCF), complete active space with second-order ...perturbation theory correction and multi-reference configuration interaction (MRCI) levels of theory. The choice of basis set, the size inconsistency of the MRCI wavefunction and the selection of the active space of the CASSCF wavefunction each have a considerable influence on the shape of the PES. In particular, the relative energy of the so-called GF and TF structures depends significantly on the level of theory employed. The results of the study suggest that the experimentally observed intermediate is more likely to be due to entropic trapping rather than the presence of a transition state.
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Bonding in the C
3H
3 radical has been determined using the topological analysis of the electron localization function (ELF) calculated with various wavefunctions (HF, LSDA, MP2, CASSCF, QCISD, BLYP, ...B3LYP). Not only is ELF independent of quantum chemical approximation, but also produced topologically equivalent molecular partitions. The ELF partition of space into localization domains provides an objective characterization of bonding in C
3H
3, supporting a resonance description of almost equal contributions of propargyl and allenyl forms. Moreover, it explains the reported difference between the frequencies of the in-plane and out-of-plane bending modes (∠C
(2)C
(3)H
(3)) arising from the topology of the C
(2)C
(3) bonding region.
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Research on infection prevention strategies (e.g., isolation precautions) to prevent healthcare-associated infections (HAIs) often requires performing an interventional study at the level of the ...inpatient unit, rather than the individual patient. Proposed interventions cannot be studied using a traditional patient-level allocation because bacterial transmission does not occur on the individual level but on a group level. These studies often are granted waived consent from institutional review boards (IRBs) for two reasons: 1) the research cannot practicably be conducted; and 2) requiring informed consent could bias the estimate of acquisition of the pathogen of interest since the more ill patients may be more likely to acquire the pathogen but less likely to consent.
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Single-ligand complexes of first series transition metals with ammonia, water, hydroxide, and fluoride, many known in the gas phase, have been studied in calculations covering the 20 mono- and ...divalent cations and some very unusual binding patterns have been found. Binding energies and binding geometries were calculated at MP2 level, using a basis with a (6d/4d) contraction in the metal d space and 6-311+G** sets for the ligands. The results were used to distinguish the effect of steadily increasing nuclear charge across the series from the varying effects of d shell occupation. Even with only one ligand, the M2+ adducts displayed the familiar ligand field effects, d shell repulsion in the expected dδ < dπ < dσ order being superimposed on a regular progression to stronger binding and shorter bonds; that progression was disturbed only at the d5 and d10 positions, when the dσ orbital was occupied. Monovalent metal adducts behaved in strikingly different fashion, with irregular changes across early and late series metals in both bond length and bond strength. The irregularities are only partly attributable to the presence of both d n -1s and d n ground states in the series. The other part of the explanation is the binding of anionic ligands inside the radial maximum of the 4s orbital. At these distances the normal binding preference shown by H2O and NH3 for d n over sd n -1 cations is reversed. In contrast to steeply rising binding energies across the divalent metal ion adducts, the trend lines for the monovalent series are flat, the increments in nuclear charge being insufficent to offset the extra repulsion of electrons added to the d shell.
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29.
Victor Levy Lucas Moriarty, N.; Entwistle, P.
BMJ,
01/2002, Volume:
324, Issue:
7329
Journal Article
Peer reviewed
Former general practitioner Southport (b Edinburgh 1918; q Edinburgh 1939), d 8 September 2001.
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30.
Phenix refine developments Grosse-Kunstleve, R. W.; Afonine, P. V.; Zwart, P. H. ...
Acta crystallographica. Section A, Foundations of crystallography,
08/2007, Volume:
63, Issue:
a1
Journal Article
Peer reviewed
Open access
Abstract only
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