Use of simulation as a needs assessment to develop a focused team leader training curriculum for resuscitation teams.

BACKGROUND: Many inpatients experience cardiac arrest and mortality in this population is extremely high. Simulation is frequently used to train code teams with the goal of improving these outcomes. A key step in designing such a training curriculum is to perform a needs assessment. We report on the effectiveness of a simulation-based training program for residents designed using unannounced in-situ simulation cardiac arrest data as a needs assessment. METHODS: In order to develop the curriculum for training, a needs assessment was done using in-situ simulation. Prior to instruction, residents were assessed in their ability to lead a simulated resuscitation using a standardized checklist. During the intervention phase, residents participated in didactic and team training. The didactic training consisted of pharmacology review, ACLS update and TeamSTEPPS training. Residents took turns as code team leader in three simulation sessions. Rapid cycle deliberate practice (RCDP) was employed as part of simulation sessions. All residents returned, for post-intervention assessment. Mean pre-post test scores were analyzed to determine if there was a significant difference. RESULTS: Twenty-seven residents participated. Mean pre-training assessment score was 47.6 (95% CI 37.5-57.9). The mean post-training assessment score was 84.4 (95% CI 79.0-89.5). The mean time to defibrillation after pads were placed in scenario with shockable rhythm decreased from 102.2 seconds (95% CI 74.0-130.5) to 56.3 (95% CI 32.7-79.8). CONCLUSION: Using unannounced in-situ cardiac arrest simulations as a needs assessment, a simulation-based training program was developed that significantly improved resident performance as team leader. Future work is needed to determine if this improvement translates into patient benefits and is sustainable. However, in-situ simulation is a promising tool for curriculum development.

Comparison of the C-H⋯O bonding in two crystalline phases of 1,4-di-thiane 1,1,4,4-tetra-oxide.

The crystal structures of two crystalline phases of 1,4-di-thiane 1,1,4,4-tetra-oxide, C4H8O4S2, have been determined in order to examine the nature of possible inter-molecular hydrogen bonds. Phase 1 is monoclinic, space group C2/m, with unit-cell dimensions of a = 9.073 (8), b = 7.077 (6), c = 5.597 (5) Šand ß = 105.89 (1)°. The mol-ecule adopts 2/m symmetry and all of the mol-ecules are related by translation and thus have the same orientation. Phase 2 is also monoclinic but in space group P21/n with unit-cell dimensions of a = 7.1305 (5), b = 5.7245 (4), c = 8.3760 (6) Šand ß = 91.138 (2)°. In this phase, the mol-ecule sits on an inversion center and the mol-ecules within the unit cell adopt quite different orientations. In both phases, examination of the potential C-H⋯O hydrogen bonds around each of the independent oxygen atoms (one axial and the other equatorial) shows the general O⋯H patterns to be quite similar with each oxygen atom in contact with four neighboring H atoms, and each H atom contacting two neighboring O atoms. While none of the H⋯O contacts is particularly short (all are greater than 2.5 Å), each mol-ecule has 32 such contacts that form an extensive inter-molecular network. A 1H NMR spectrum of the compound dissolved in DMSO shows a singlet of 8H at δ 3.677 which indicates that the C-H bonds are only moderately polarized by the single adjacent -SO2- moiety: strongly polarized C-H bonds have δ values in the 5-6 range [Li & Sammes (1983 ▸). J. Chem. Soc. Perkin Trans. 1, pp. 1303-1309]. The phase 1 crystal studied was non-merohedrally twinned.

Using phase shift Granger causality to measure directed connectivity in EEG recordings.

Cortical activity is maintained by neural networks working in tandem. Electroencephalographic (EEG) signals across two sites are said to be coherent with one another when they show consistent phase relations. However, periods of desynchrony beginning with a shift in phase relations are a necessary aspect of information processing. Traditional measures of EEG coherence lack the temporal resolution required to divide the relationship between two signals into periods of synchrony and desynchrony and are unable to specify the direction of information transmission (i.e., which site is leading and which is lagging), a goal referred to as directed connectivity. In this article, the authors introduce a novel method of measuring directed connectivity by applying the framework of Granger causality to phase shift events which are estimated with high temporal resolution. A simulation study is used to verify that the proposed method is able to identify connectivity patterns in situations similar to EEG recordings, such as high levels of noise and linear source mixing. Their method is able to correctly identify both the existence and direction of information transfer, and that the existence of spatiotemporal noise serves to reduce the spread of shift identification due to volume conduction. To demonstrate the method on real data, it is applied to EEG recordings from 18 adolescents during a resting period and auditory and visual vigilance tasks. Their new measure, Phase Shift Granger Causality (PSGC), is able to clearly distinguish between the resting task and the active tasks. The latter have higher rates of connectivity overall and specifically more long-range connections. As expected, the resting task appears to activate more localized neural circuitry, whereas the active tasks appear to increase communication across several neural regions involved in vigilance tasks. The vigilance tasks also showed significantly higher clustering coefficients than the resting task, a property associated with small-world networks.

Adolescent anxiety and aggression can be differentially predicted by electrocortical phase reset variables.

Increasing evidence supports the notion that both internalizing (e.g., anxiety) and externalizing (e.g., aggression) behavioral dysregulation are associated with abnormal communication between brain regions. Electroencephalographic (EEG) signals across two electrode sites are said to be coherent with one another when they show consistent phase relations. However, periods of desynchrony with shifting of phase relations are a necessary aspect of information processing. The components of EEG phase reset ('locking' when two regions remain in synchrony, and 'shifting' when the two regions desynchronize momentarily) show dramatic changes across development. We collected resting EEG data from typically developing 12 to 15-year-olds and calculated phase shift and lock values in the alpha frequency band across 14 pairs of electrodes varying in inter-electrode distance. A composite measure of participants' aggression levels was positively associated with phase shifting, particularly in the low alpha frequency range, most strongly over the left hemisphere, consistent with the relatively greater left-prefrontal activity reported in aggressive adults. A composite measure of anxiety levels was positively associated with alpha phase locking at sites over both hemispheres, consistent with changes in connectivity reported during anxious thinking in adults. Associations with anxiety could not be explained by traditional EEG coherence measures and suggest that phase shifting and locking might provide an important non-invasive associate of clinically problematic behavior.

Fluxionality of [(Ph3P)3M(X)] (M = Rh, Ir). The red and orange forms of [(Ph3P)3Ir(Cl)]. Which phosphine dissociates faster from Wilkinson's catalyst?

NMR studies of intramolecular exchange in [(Ph(3)P)(3)Rh(X)] (X = CF(3), CH(3), H, Ph, Cl) have produced full sets of activation parameters for X = CH(3) (E(a) = 16.4 +/- 0.6 kcal mol(-1), DeltaH(double dagger) = 16.0 +/- 0.6 kcal mol(-1), and DeltaS(double dagger) = 12.7 +/- 2.5 eu), H (E(a) = 10.7 +/- 0.2 kcal mol(-1), DeltaH(double dagger) = 10.3 +/- 0.2 kcal mol(-1), and DeltaS(double dagger) = -7.2 +/- 0.8 eu), and Cl (E(a) = 16.3 +/- 0.2 kcal mol(-1), DeltaH(double dagger) = 15.7 +/- 0.2 kcal mol(-1), and DeltaS(double dagger) = -0.8 +/- 0.8 eu). Computational studies have shown that for strong trans influence ligands (X = H, Me, Ph, CF(3)), the rearrangement occurs via a near-trigonal transition state that is made more accessible by bulkier ligands and strongly donating X. The exceedingly fast exchange in novel [(Ph(3)P)(3)Rh(CF(3))] (12.1 s(-1) at -100 degrees C) is due to strong electron donation from the CF(3) ligand to Rh, as demonstrated by computed charge distributions. For weaker donors X, this transition state is insufficiently stabilized, and hence intramolecular exchange in [(Ph(3)P)(3)Rh(Cl)] proceeds via a different, spin-crossover mechanism involving triplet, distorted-tetrahedral [(Ph(3)P)(3)Rh(Cl)] as an intermediate. Simultaneous intermolecular exchange of [(Ph(3)P)(3)Rh(Cl)] with free PPh(3) (THF) via a dissociative mechanism occurs exclusively from the sites cis to Cl (E(a) = 19.0 +/- 0.3 kcal mol(-1), DeltaH(double dagger) = 18.5 +/- 0.3 kcal mol(-1), and DeltaS(double dagger) = 4.4 +/- 0.9 eu). Similar exchange processes are much slower for [(Ph(3)P)(3)Ir(Cl)] which has been found to exist in orange and red crystallographic forms isostructural with those of [(Ph(3)P)(3)Rh(Cl)].

A rearrangement of 1,1-linked four-membered rings to bicyclic bridgehead five-membered rings: a phosphorus turn.

Novel rearrangements of 2,3,2',3'-tetra-tert-butyl-4,4'-bis-trimethylsilanyloxy-1,2,1',2'-tetrahydro-[1,1']biphosphetyl (7) to 1,2,5,6-tetra-tert-butyl-3,7-bis-trimethylsilanyloxy-1H,5H-[1,2]diphospholo-[1,2-a][1,2]diphosphole (9) and of 3,4,3,4-tetra-tert-butyl-[1,1']biphosphetanyl-2,2'-dione (10) to 2,3,6,7-tetra-tert-butyl-tetrahydro-[1,2]diphospholo[1,2-a][1,2]diphosphole-1,5-dione (12) were observed during sublimation at 150 degrees C in 0.1 mm vacuum. The C-P-C internal angles of the four-membered rings, which reflect steric strain in (7), were 71.9(2) degrees and 77.9(1) degrees; the C-P-P internal angles of the five-membered rings of 9 were 90.88(6) degrees and 93.02(6) degrees after rearrangement. Reaction of 7 with metallic caesium provided the caesium salt of 3,4-di-tert-butyl-3,4-dihydro-phosphet-2-ol (15), which is the first example of a 2lambda-3-phospha-1-enolate being incorporated into four-membered ring. Due to its large size, the caesium cation has a rare coordination mode with both the phosphorus and oxygen atoms of the 2lambda-3-phospha-1-enolate, forming infinite polymeric chains in the solid state of 15. Two tert-butyl groups in the vicinal positions of compounds 7, 9, 10, 12 and 15 dictate the gauche conformations in compounds 7, 9, 10, 12 and 15, enforcing this stereoselectivity around the C-C-C portion of the rings in the enlargement reaction.

Synthesis of ruthenium carbonyl complexes with phosphine or substituted Cp ligands, and their activity in the catalytic deoxygenation of 1,2-propanediol.

A ruthenium hydride with a bulky tetra-substituted Cp ligand, (Cp(i)(Pr(4)))Ru(CO)(2)H (Cp(i)(Pr(4)) = C(5)(i-C(3)H(7))(4)H) was prepared from the reaction of Ru(3)(CO)(12) with 1,2,3,4-tetraisopropylcyclopentadiene. The molecular structure of (Cp(i)(Pr(4)))Ru(CO)(2)H was determined by X-ray crystallography. The ruthenium hydride complex (C(5)Bz(5))Ru(CO)(2)H (Bz = CH(2)Ph) was similarly prepared. The Ru-Ru bonded dimer, [(1,2,3-trimethylindenyl)Ru(CO)(2)](2), was produced from the reaction of 1,2,3-trimethylindene with Ru(3)(CO)(12), and protonation of this dimer with HOTf gives {[(1,2,3-trimethylindenyl)Ru(CO)(2)](2)-(mu-H)}(+)OTf (-). A series of ruthenium hydride complexes CpRu(CO)(L)H [L = P(OPh)(3), PCy(3), PMe(3), P(p-C(6)H(4)F)(3)] were prepared by reaction of Cp(CO)(2)RuH with added L. Protonation of (Cp(i)(Pr(4)))Ru(CO)(2)H, Cp*Ru(CO)(2)H, or CpRu(CO)[P-(OPh)(3)]H by HOTf at -80 degrees C led to equilibria with the cationic dihydrogen complexes, but H(2) was released at higher temperatures. Protonation of CpRu[P(OPh)(3)](2)H with HOTf gave an observable dihydrogen complex, {CpRu[P-(OPh)(3)](2)(eta(2)-H(2))}(+)OTf (-) that was converted at -20 degrees C to the dihydride complex {CpRu[P(OPh)(3)](2)(H)(2)}(+)OTf (-). These Ru complexes serve as catalyst precursors for the catalytic deoxygenation of 1,2-propanediol to give n-propanol. The catalytic reactions were carried out in sulfolane solvent with added HOTf under H(2) (750 psi) at 110 degrees C.

Fluxionality of [(Ph3P)3Rh(X)]: the extreme case of X = CF3.

[(Ph(3)P)(3)Rh(F)] reacts with CF(3)SiMe(3) to produce trans-[(Ph(3)P)(2)Rh(CF(2))(F)] (1; X-ray), which is equilibrated with a number of species in solution. Addition of excess Ph(3)P shifts all of the equilibria to [(Ph(3)P)(3)Rh(CF(3))] (2; X-ray) as the only NMR-observable and isolable (84%) species. Complex 2 is uniquely highly fluxional in solution, maintaining ligand exchange even at -100 degrees C (12.1 s(-1)). Activation parameters have been determined (variable-temperature (31)P NMR) for the similar but slower exchange in the Me analogue of 2, [(Ph(3)P)(3)Rh(CH(3))]: E(a) = 16.5 +/- 0.6 kcal mol(-1), DeltaG(double dagger) = 12.9 kcal mol(-1) (calculated at -30 degrees C), DeltaH(double dagger) = 16.0 +/- 0.6 kcal mol(-1), and DeltaS(double dagger) = 12.8 +/- 2.3 e.u. Intramolecular exchange in [(R(3)P)(3)Rh(X)] occurs (DFT, MP2//BP86) via a distorted trigonal transition state (TS) with X in an axial position trans to a vacant site. The rearrangement is governed by a combination of steric and electronic factors and is facilitated by bulkier ligands on Rh as well as by strongly donating X that stabilize the TS. The Rh atom in [(H(3)P)(3)Rh(X)] has been shown to be more negatively charged (NPA) for X = CF(3) than for X = CH(3), despite the strongly oppositely charged carbon atoms of the CF(3) (+0.79e) and CH(3) (-0.96e) ligands. Clarification of stereochemical rigidity (X = halide, CN, OR, NR(2)) versus fluxionality (X = H, Alk, Ar, CF(3)) is provided, along with a resolution of the long-standing contradiction between the electron-withdrawing effect of CF(3) in organic compounds and its strong trans influence (electron donation) in metal complexes.

trans-Difluoro complexes of palladium(II).

Complexes trans-[(Py)(2)Pd(Ph)(F)] (1; Py = pyridine) and trans-[(t-BuPy)(2)Pd(Ph)(F)] (2; t-BuPy = 4-tert-butylpyridine) have been prepared from the corresponding iodides and AgF. Thermal decomposition of 1 and 2 in anhydrous benzene at 80 degrees C did not result in C-F bond formation, but Pd black and Ph(2) were produced instead, along with novel difluorides trans-[(Py)(2)Pd(F)(2)] (3) and trans-[(t-BuPy)(2)Pd(F)(2)] (4). Both 3 and 4, the first trans-difluoro d(8) square complexes, were independently synthesized from the corresponding diiodides and AgF and fully characterized. Contrary to filled/filled d(pi)-p(pi) repulsion considerations, the Pd-F bond distances in 3 and 4 are unprecedentedly short, being only 1.947(4)-1.958(4) A and shorter than those in 1 and 2 by 0.12-0.13 A. The mechanism of formation of 3 and 4 and bonding in these complexes are discussed.

A stable enol in small ring systems: clear differentiation between penta- and tri-valency of phosphorus atoms.

The first stable enols in 1,2-dihydrophosphetes and were synthesized and structurally characterized with intermolecular hydrogen bonds to phosphoryl groups in 10-membered dimeric structures; in contrast, trivalent analogue exists in keto-form, where such stabilization by hydrogen bonds is not feasible.

Highly sterically hindered olefins: a case of E- and Z-di-tert-butyl alpha,beta-unsaturated acids.

Use of a superbase in the Favorskii rearrangement of 12 resulted in the synthesis of highly sterically hindered olefins, (E)-2- tert-butyl-4,4-dimethyl-pent-2-enoic acid (4) and (Z)-2- tert-butyl-4,4-dimethyl-pent-2-enoic acid (3).

A tetra-substituted chrysene: orientation of multiple electrophilic substitution and use of a tetra-substituted chrysene as a blue emitter for OLEDs.

The first tetra-substituted non-fused chrysene, 3,6,9,12-tetrakis(4-tert-butylphenyl)chrysene with blue electroluminescence at 450 nm, and with a radiance of 500 cd m(-2), was synthesized by a two-step procedure: direct bromination of chrysene in trimethyl phosphate, followed by palladium-catalyzed cross-coupling of tetrabromochrysene and tert-butylphenylboronic acid .

Mechanisms of catalyst poisoning in palladium-catalyzed cyanation of haloarenes. remarkably facile C-N bond activation in the [(Ph3P)4Pd]/[Bu4N]+ CN- system.

Reaction paths leading to palladium catalyst deactivation during cyanation of haloarenes (eq 1) have been identified and studied. Each key step of the catalytic loop (Scheme 1) can be disrupted by excess cyanide, including ArX oxidative addition, X/CN exchange, and ArCN reductive elimination. The catalytic reaction is terminated via the facile formation of inactive [(CN)4Pd]2-, [(CN)3PdH]2-, and [(CN)3PdAr]2-. Moisture is particularly harmful to the catalysis because of facile CN- hydrolysis to HCN that is highly reactive toward Pd(0). Depending on conditions, the reaction of [(Ph3P)4Pd] with HCN in the presence of extra CN- can give rise to [(CN)4Pd]2- and/or the remarkably stable new hydride [(CN)3PdH]2- (NMR, X-ray). The X/CN exchange and reductive elimination steps are vulnerable to excess CN- because of facile phosphine displacement leading to stable [(CN)3PdAr]2- that can undergo ArCN reductive elimination only in the absence of extra CN-. When a quaternary ammonium cation such as [Bu4N]+ is used as a phase-transfer agent for the cyanation reaction, C-N bond cleavage in the cation can occur via two different processes. In the presence of trace water, CN- hydrolysis yields HCN that reacts with Pd(0) to give [(CN)3PdH]2-. This also releases highly active OH- that causes Hofmann elimination of [Bu4N]+ to give Bu3N, 1-butene, and water. This decomposition mode is therefore catalytic in H2O. Under anhydrous conditions, the formation of a new species, [(CN)3PdBu]2-, is observed, and experimental studies suggest that electron-rich mixed cyano phosphine Pd(0) species are responsible for this unusual reaction. A combination of experimental (kinetics, labeling) and computational studies demonstrate that in this case C-N activation occurs via an S(N)2-type displacement of amine and rule out alternative 3-center C-N oxidative addition or Hofmann elimination processes.

A stabilized beta-oxaphosphoniumbetaine: an elusive zwitterion.

A beta-oxaphosphoniumbetaine stabilized by two tert-butyl groups at the phosphonium part of the betaine and two trifluoromethyl groups at the carbon adjoined to the oxa part of the betaine was isolated and structurally characterized. Additional stabilization results from the solvation of the betaine by a parent phosphonium salt, as in 4, or by protonation with methanol, as in 10. According to X-ray analysis, the betaine exhibits a sterically strained "gauche" conformeric form, with torsion angles in the P-C-C-O moiety of 32.2 degrees for 4 and 28.1 degrees for 10. The P...O separations of 3.121 A for 4 and 3.086 A for 10 are just under the sum of the O and P van der Waals radii (3.32 A). The fast H/D exchange of alpha hydrogen atoms to the phosphonium center was observed in the solution of 10 in deuterium oxide and MeOH-d4. The beta-oxaphosphoniumbetaine has long been suspected as an intermediate in the Wittig reaction, but this is the first time a stabilized derivative has been isolated.

Facile Ar-CF3 bond formation at Pd. Strikingly different outcomes of reductive elimination from [(Ph3P)2Pd(CF3)Ph] and [(Xantphos)Pd(CF3)Ph].

Facile and highly selective perfluoroalkyl-aryl reductive elimination from a metal center (Pd) has been demonstrated for the first time. At temperatures as low as 50-80 degrees C, [(Xantphos)Pd(Ph)CF3] undergoes remarkably clean decomposition to produce CF3Ph in high yield and selectivity. In contrast, analogous trifluoromethylpalladium aryls stabilized by rigid cis-chelating ligands such as dppe are completely unreactive at temperatures up to 130-140 degrees C. Decomposition of [(Ph3P)2Pd(Ph)CF3] in the presence of PhI in benzene at 60 degrees C does not produce PhCF3 but rather leads to [(Ph3P)2Pd(Ph)I] and [Ph4P]+[(Ph3P)Pd(CF3)3]- in a 2:1 ratio with high selectivity.

Synthesis, structural characterization and the first electroluminescent properties of tris- and bis-cycloiridiated complexes of sterically hindered electron-poor 2-(3,5-bis(trifluoromethyl)phenyl)-4-trifluoromethylpyridine.

An application of the new sterically hindered electron-poor 2-(3,5-bis(trifluoromethyl)phenyl)-4-trifluoromethylpyridine [HC--N] (1) in the one-step high temperature cyclometalation by Ir(III)Cl3 in the presence of Ag(I)OC(O)CF3 resulted in the synthesis of tris-cyclometalated complexes [C--N]2Ir[C--C] (3) and [C--N]3Ir (5). A neutral silver cluster with a repeating unit of hexa-silver groups in an infinite chain of (2) was isolated from the above reaction as well. When this cyclometalation was carried out in trimethylphosphate at lower temperature, bis-cyclometalated derivatives [C--N]2Ir(mu-Cl)2Ir[CN]2 (6), [C--N]2Ir[eta2-(O(C((t)Bu))2CH] (7), and [C--N]2Ir(mu-O-P(OMe)2-O)2Ir[C--N]2 (8) were synthesized. According to X-ray analyses complex (3), while trivalent, contains four cyclometalated single Ir-C bonds. One of the Ir-C bonds, next to the nitrogen atom of the CC pyridinium ligand, was found to be the shortest to date (1.977(4) angstroms) for a single bond between iridium and carbon atoms. The coordination of the C--C ligand in (3) to iridium has a decidedly interesting bonding pattern and can be explained by various formulations. The first one is considering this ligand as a monoanionic chelating ligand, in which the second coordination site arises from a carbene or azomethine ylide. Overall the best single picture may be a dianionic ligand making two normal Ir-C bonds, in which the ligand just happens to contain a pyridinium function that compensates for one negative charge on the iridium. LEDs constructed with compounds (7) and (8) give blue-green emission with peak electroluminescent efficiency of 15 and 2 cd A(-1), respectively. An LED constructed with compound (5) gives a yellowish emission with peak electroluminescent efficiency of 5.5 cd A(-1).