Nickel-catalysed hydroalkoxylation reaction of 1,3-butadiene: ligand controlled selectivity for the efficient and atom-economical synthesis of alkylbutenyl ethers.

The nickel-catalysed hydroalkoxylation of butadiene is promoted by a nickel(0)/dppb catalyst (dppb = 1,4-bis(diphenylphosphino)butane; see scheme). By following this new synthetic procedure, alkylbutenyl ethers are readily obtained from an alcohol and 1,3-butadiene with exclusion of dimerisation and telomerisation products.

Procalcitonin is a predictor for high-grade vesicoureteral reflux in children: meta-analysis of individual patient data.

OBJECTIVE: To assess the predictive value of procalcitonin, a serum inflammatory marker, in the identification of children with first urinary tract infection (UTI) who might have high-grade (≥3) vesicoureteral reflux (VUR). STUDY DESIGN: We conducted a meta-analysis of individual data, including all series of children aged 1 month to 4 years with a first UTI, a procalcitonin (PCT) level measurement, cystograms, and an early dimercaptosuccinic acid scan. RESULTS: Of the 152 relevant identified articles, 12 studies representing 526 patients (10% with VUR ≥3) were included. PCT level was associated with VUR ≥3 as a continuous (P = .001), and as a binary variable, with a 0.5 ng/mL preferred threshold (adjusted OR, 2.5; 95% CI, 1.1 to 5.4). The sensitivity of PCT ≥0.5 ng/mL was 83% (95% CI, 71 to 91) with 43% specificity rate (95% CI, 38 to 47). In the subgroup of children with a positive results on dimercaptosuccinic acid scan, PCT ≥0.5 ng/mL was also associated with high-grade VUR (adjusted OR, 4.8; 95% CI, 1.3 to 17.6). CONCLUSIONS: We confirmed that PCT is a sensitive and validated predictor strongly associated with VUR ≥3, regardless of the presence of early renal parenchymal involvement in children with a first UTI.

Click grafting of seaweed polysaccharides onto PVC surfaces using an ionic liquid as solvent and catalyst.

Seaweed antibacterial polysaccharides were grafted onto poly(vinylchloride) (PVC) surfaces using an original click chemistry pathway. PVC isothiocyanate surfaces (PVC-NCS) were first prepared by nucleophilic substitution of the chloride groups by isothiocyanate groups in DMSO/water medium. Then, unmodified Ulvan, Fucan, Laminarin or Zosterin was directly grafted onto the PVC-NCS surface using 1-ethyl-3-methyl imidazolium phosphate, an ionic liquid, as solvent and catalyst. To attest the grafting effectiveness, the new PVC surfaces were well characterized by AFM, XPS and contact angle measurements.

Telomerisation of 1,3-butadiene with 1,4:3,6-dianhydrohexitols: an atom-economic and selective synthesis of amphiphilic monoethers from agro-based diols.

The telomerisation of 1,3-butadiene with a Pd/TPPTS catalytic system in water or an organic solvent was used for the synthesis of C8 ethers from isosorbide, an agro-based diol. The use of water/oil biphasic reaction conditions allowed the selective synthesis of monoethers with improved rates upon using inorganic bases as promotors. As isosorbide is a non-symmetric diol, the two hydroxyl groups display different reactivities. 2-O-substituted-monoethers were preferentially obtained if water was used as the solvent, whereas in DMSO 5-O-substituted monoethers were the major products. Complete conversions of isosorbide with up to 94% monoether selectivities were obtained. The optimized reaction conditions were successfully applied to isomannide and isoidide for the selective synthesis of the derived ethers. An improved reactivity of the endo-hydroxy groups of isosorbide and isomannide versus the exo-hydroxy groups of isosorbide and isoidide was observed if the reaction was performed in DMSO instead of water.

Prediction of high-grade vesicoureteral reflux after pediatric urinary tract infection: external validation study of procalcitonin-based decision rule.

BACKGROUND: Predicting vesico-ureteral reflux (VUR) ≥3 at the time of the first urinary tract infection (UTI) would make it possible to restrict cystography to high-risk children. We previously derived the following clinical decision rule for that purpose: cystography should be performed in cases with ureteral dilation and a serum procalcitonin level ≥0.17 ng/mL, or without ureteral dilatation when the serum procalcitonin level ≥0.63 ng/mL. The rule yielded a 86% sensitivity with a 46% specificity. We aimed to test its reproducibility. STUDY DESIGN: A secondary analysis of prospective series of children with a first UTI. The rule was applied, and predictive ability was calculated. RESULTS: The study included 413 patients (157 boys, VUR ≥3 in 11%) from eight centers in five countries. The rule offered a 46% specificity (95% CI, 41-52), not different from the one in the derivation study. However, the sensitivity significantly decreased to 64% (95%CI, 50-76), leading to a difference of 20% (95%CI, 17-36). In all, 16 (34%) patients among the 47 with VUR ≥3 were misdiagnosed by the rule. This lack of reproducibility might result primarily from a difference between derivation and validation populations regarding inflammatory parameters (CRP, PCT); the validation set samples may have been collected earlier than for the derivation one. CONCLUSIONS: The rule built to predict VUR ≥3 had a stable specificity (ie. 46%), but a decreased sensitivity (ie. 64%) because of the time variability of PCT measurement. Some refinement may be warranted.