Objective To establish an algorithm for first‐trimester combined screening for trisomy 21 with biochemical testing from 7 to 14 weeks' gestation and ultrasound testing at 11–13 weeks. Methods This was a multicenter study of 886 pregnancies with trisomy 21 and 222 475 unaffected pregnancies with measurements of free β‐human chorionic gonadotropin (β‐hCG) and pregnancy‐associated plasma protein‐A (PAPP‐A) at 7–14 weeks' gestation. Multiple regression modeling of log‐transformed marker values was used to produce log multiples of the median (MoM) values for PAPP‐A and free β‐hCG. The models included terms for the center attended and the machine used for biochemical analysis, gestational age, maternal racial origin, maternal weight, smoking status and method of conception. Bivariate Gaussian distributions were fitted to log MoM PAPP‐A and log MoM free β‐hCG in trisomy 21 and in unaffected pregnancies. In each case the patient‐specific risk for trisomy 21 was estimated by multiplying the individual maternal age‐related risk with the likelihood ratio (LR) for fetal nuchal translucency (NT) according to the mixture model and the combined LR for maternal serum free β‐hCG and PAPP‐A. Estimates of detection rates for trisomy 21 and false‐positive rates were calculated for combined screening with measurements of NT at 12 weeks together with measurements of free β‐hCG and PAPP‐A from 8 to 13 weeks. Results In trisomy 21 pregnancies the mean log MoM free β‐hCG increased linearly with gestation between 7 and 14 weeks, whereas the relation between log MoM PAPP‐A and gestation was fitted by a quadratic equation such that the maximum separation between trisomy 21 and unaffected pregnancies occurs at 9–10 weeks. At a false‐positive rate of 3% the detection rate of combined screening at 12 weeks was 86% and this increased to 90% by biochemical testing at 9 weeks and ultrasound scanning at 12 weeks. The detection rate increased to 92% by measuring PAPP‐A at 9 weeks and free β‐hCG at the time of the scan at 12 weeks. Conclusion The performance of first‐trimester biochemical screening for trisomy 21 is best at 9–10 weeks rather than at 7–8 or 11–14 weeks. Copyright © 2010 ISUOG. Published by John Wiley & Sons, Ltd.

Linear organogelators 1 and 2, which self-assemble cooperatively into fibrillar structures, act as efficient crystal growth media for common pharmaceutical ingredients like ASP, CAF, IND and CBZ.

Lead(II) acetate [Pb(Ac)2, where Ac = acetate group (CH3-COO(-))2] is a very common salt with many and varied uses throughout history. However, only lead(II) acetate trihydrate [Pb(Ac)2·3H2O] has been characterized to date. In this paper, two enantiotropic polymorphs of the anhydrous salt, a novel hydrate [lead(II) acetate hemihydrate: Pb(Ac)2·(1)/2H2O], and two decomposition products [corresponding to two different basic lead(II) acetates: Pb4O(Ac)6 and Pb2O(Ac)2] are reported, with their structures being solved for the first time. The compounds present a variety of molecular arrangements, being 2D or 1D coordination polymers. A thorough thermal analysis, by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA), was also carried out to study the behavior and thermal data of the salt and its decomposition process, in inert and oxygenated atmospheres, identifying the phases and byproducts that appear. The complex thermal behavior of lead(II) acetate is now solved, finding the existence of another hydrate, two anhydrous enantiotropic polymorphs, and some byproducts. Moreover, some of them are phosphorescent at room temperature. The compounds were studied by TGA, DSC, X-ray diffraction, and UV-vis spectroscopy.

We have recently discovered significant amounts of zaccagnaite, a natural Zn-Al-CO 3 hydrotalcite in the El Soplao cave (north Spain). The El Soplao zaccagnaite is speleothemic, i.e., formed in the cave, and therefore it represents a new cave mineral. The origin of El Soplao zaccagnaite is related to the diagenesis of Zn-and Al-rich ferromanganese speleo-stromatolites, where it occurs as a porefilling cement that likely precipitated at low temperature (≤ ~11 °C). In some stromatolite layers, the abundance of zaccagnaite crystals is large enough to enable their physical separation. This has allowed us to obtain its X-ray powder-diffraction pattern, infrared spectrum, and differential thermal/ thermogravimetric profiles.The cell parameters of the El Soplao zaccagnaite, refined from X-ray powder diffraction data are: a = 3.06616(1) and c = 22.6164(1) Å [α = β = 90°, γ = 120°; V = 184.139(1) Å 3 ; Z = 3], consistent with a new trigonal polytype of zaccagnaite: zaccagnaite-3R. Besides, the El Soplao zaccagnaite shows some features previously unknown in natural hydrotalcites, such as octahedral-like morphologies and fluorescence zoning. Electron microprobe analyses revealed that the El Soplao zaccagnaite-3R has an unusual chemistry for natural hydrotalcites, as it is significantly more rich in Al (Zn 2+ /Al 3+ = 1.6) than the hexagonal (2H) polytype (Zn 2+ /Al 3+ = 2.0). The simplified chemical formula deduced from electron microprobe analysis is (Zn 0.6 Al 0.4 )(OH) 2 (CO 3 ) 0.2 ⋅0.5H 2 O, where C and water were calculated by stoichiometry. The carbon content calculated by stoichiometry (2.2 wt%) is in good agreement with that measured with the electron microprobe on gold-coated samples (2.5 wt%). The presence of interlayer water and CO 3 groups was confirmed by thermogravimetric analysis coupled to mass spectroscopy, and by the analysis of the infrared spectrum.

The morphology of the aggregates formed from the self-assembly of aryl triazole amphiphiles is disrupted upon the binding of a bromide anion due to the conformational changes experienced by these receptors.