Prediction and prevention of early-onset pre-eclampsia: impact of aspirin after first-trimester screening.

OBJECTIVE: To examine the effect of a combination of screening and treatment with low-dose aspirin on the prevalence of early-onset pre-eclampsia (PE). METHODS: This was a retrospective analysis of two consecutive cohorts of women screened for early PE. The first cohort was observed to determine whether algorithms developed to screen for PE at 11 to 13 + 6 weeks' gestation could be applied to our population. High-risk women in the second cohort were advised on their risk and offered aspirin (150 mg at night), with treatment starting immediately after screening. The prevalence of early PE and the proportion of women with PE delivering at 34-37 weeks' gestation were compared between the cohorts. RESULTS: In the observational and interventional cohorts, 3066 and 2717 women, respectively, were screened. There were 12 (0.4%) cases of early PE in the observational cohort and one (0.04%) in the interventional cohort (P < 0.01). Among all women with PE delivering before 37 weeks, 25 (0.83%) were in the observational cohort and 10 (0.37%) in the interventional cohort (P = 0.03). CONCLUSIONS: A strategy of first-trimester screening for early PE coupled with prescription of aspirin to the high-risk group appears to be effective in reducing the prevalence of early PE.

Macrocycles, catenanes, oligomers and polymers in gold chemistry.

A critical review is given of the chemistry of macrocycles, catenanes, oligomers and polymers in gold chemistry. Because gold centres are typically labile towards ligand substitution, there may be an easy equilibrium between the cyclic and linear oligomeric or polymeric forms and the preferred products of self-assembly are usually determined by thermodynamic control. The ways in which the self-assembly of complex structures from simple building blocks by dynamic coordination chemistry can be manipulated by ligand design or by the use of secondary bonding forces is emphasized (39 references).

Self-assembly of polymer and sheet structures from palladium(II) complexes by hydrogen bonding between carboxamide substituents.

The self-assembly of supramolecular structures from either neutral or cationic palladium(II) complexes containing primary or secondary carboxamide groups as substituents on pyridine ligands has been explored. The displacement of PhCN in trans-[PdCl(2)(PhCN)(2)] by L = N-methylnicotinamide (MNA), isonicotinamide (INA), or nicotinamide (NA) gave the corresponding complexes trans-[PdCl(2)L(2)] 1-3, respectively. Complex 1.H(2)O forms a 2D sheet network via amide-amide hydrogen bonding supported by chloride ligand-to-water hydrogen-bonding interactions. Several cationic complexes, [Pd(L'L')L(2)](2+) 4-9 and 11-16, containing the above ligands and with PPh(3), dppp, dppm, or bu(2)bipy as ancillary ligand(s) were prepared. Complex 4 (L = MNA, L'L' = dppp) forms dimers through amide-amide hydrogen bonding, forming macrocycles which further propagate to form chains via weak C-H...O=C hydrogen bonding. Complex 6 (L = NA, L'L' = dppp) forms zigzag chains connected by amide head-to-head hydrogen bonds. Complex 8 (L = INA, L'L' = dppm) gives interesting double-stranded ribbons linked by two types of amide--amide hydrogen-bonding interactions. Complex 13 (L' = PPh(3), L = NA) forms an infinite chain via complementary amide-amide hydrogen bonds. Complex 14 (L = MNA, L'L' = bu(2)bipy) forms infinite ribbons via the combination of amide hydrogen bonding mediated by a BF(4) anion and weak C-H...O=C hydrogen bonding. Complex 15 (L = INA, L'L' = bu(2)bipy) gives a ladder polymer formed through amide--amide hydrogen bonds. The structure of cis-[Pd(PPh(3))(2)(OH(2))(2)] (OTf)(2) (10) is also reported.

Self-assembly of rings, catenanes, and a doubly braided catenane containing gold(I): the hinge-group effect in diacetylide ligands.

Reaction of the flexible dialkynyldigold(I) precursors X(4-C6H4OCH2C-CAu)2 with 1,4-bis(diphenylphosphino)butane gave complexes of formula [[[mu-X(4-C6H4OCH2CCAu)2[mu-(Ph2PCH2CH2CH2CH2PPh2)]]n]. The complexes exist as 25-membered ring compounds with n = 1 when X = O or S, as [2]catenanes with n = 2 when X = CH2 or CMe2, and as a unique doubly braided [2]catenane, containing interlocked 50-membered rings with n = 4 when X = cyclohexylidene. These compounds form easily and selectively by self-assembly; reasons for the selectivity are also discussed.

Variable-Energy Photoelectron Spectroscopy of (eta(5)-C(5)H(5))NiNO: Molecular Orbital Assignment and Xalpha-SW Calculations.

Variable-energy valence and inner-valence photoelectron spectra have been recorded for the CpNiNO complex (Cp = eta(5)-C(5)H(5)) between 21.2 and 100 eV, using He I radiation and synchrotron radiation. The ground state electronic structure has been calculated by using the Xalpha-SW method. Photoionization cross sections (sigma) have also been calculated for the valence ionizations using the Xalpha-SW method. The theoretical branching ratios (sigma(i)/ summation operatorsigma) have been compared with the observed branching ratios (A(i)()/ summation operatorA) between 21.2 and 100 eV. The assignment of the photoelectron spectrum based on the analysis of intensity variations and width of vibrational peaks is consistent with the ion state orbital ordering 5e(1)(1) < 7a(1)(2) < 3e(2)(3) < 4e(1)(4) (band numbers are in parentheses) and is inconsistent with another recently proposed ordering 5e(1)(1), 5e(1)(2) < 7a(1), 3e(2)(3) < 4e(1)(4), which takes the 5e(1) vibronic effects into consideration. The experimental branching ratio results indicate a Ni 3p resonance effect around 75 eV in the photoionization process. The inner-valence spectrum has also been assigned with the aid of the Xalpha-SW calculations.