Effect of hyperglycemia on all-cause mortality from pediatric brain injury: A systematic review and meta-analysis.

BACKGROUND: This study aimed to assess the effect of hyperglycemia on all-cause mortality in pediatric patients with brain injury, based on currently available evidence. METHODS: We systematically searched the PubMed, Embase, and Cochrane Library databases with the keywords "hyperglycemia", "brain injury", and "pediatrics". The retrieved records were screened by title, abstract, and full-text to include original articles assessing the effects of hyperglycemia on pediatric brain injury. The extracted data were assessed by a fixed-effects model. The risk of bias in the eligible studies was evaluated with the Newcastle-Ottawa Scale. Publication bias was visually examined with a funnel plot. Begg and Egger tests, respectively, were used to identify small-study effects. Sensitivity analysis was performed to evaluate the robustness of the original effect size. RESULTS: Nine observational studies were identified from 1439 primary hits. A total of 970 pediatric patients, including 304 with hyperglycemia and brain injury, were included for meta-analysis. Hyperglycemia was strongly associated with a higher risk of all-cause mortality in pediatric patients (odds ratio = 11.60, 95% confidence interval [CI] 7.88-17.08; I = 0%). The overall quality of eligible studies was low, but the funnel plot indicated no publication bias. CONCLUSIONS: Hyperglycemia is significantly associated with high all-cause mortality in pediatric patients with brain injury. However, the relationship should be confirmed by larger-scale observational studies and randomized controlled trials.

Chain Transfer to Toluene in Styrene Coordination Polymerization.

The chain-transfer reaction is rather important in coordination polymerization regarding catalytic efficiency, adjustment of molecular weight, and control of chain structure. To date, chain transfer to H2 and Al, Mg, and Zn alkyl compounds and ß-H elimination are the commonly encountered modes. Now a novel chain transfer to toluene is reported. By introducing fluorine atoms into the ß-diketimine ligands, an inert catalytic system for styrene (St) coordination polymerization was transferred into the highly active one. The activity increased with an increase in the number of fluorines in the ligands. Surprisingly, the molecular weights of resultant polystyrenes are very low (Mn =2000-6600 Da) despite of St loadings, corresponding up to 121 chains per active species. The mechanisms were investigated by DFT simulation, MALDI-TOF MS, isotope tracing experiment and 2D NMR spectrum analyses, which revealed that the fluorine activated the polymerization and directed chain transfer to toluene.

Highly 2,3-Selective Polymerization of Phenylallene and Its Derivatives with Rare-Earth Metal Catalysts: From Amorphous to Crystalline Products.

Rare-earth metal complexes (Flu-CH2 -Py)Ln(CH2 SiMe3 )2 (THF)n (Ln=Sc(1), Lu(2), Tm(3), Y(4) and Gd(5)), upon the activation of [Ph3 C][B(C6 F5 )4 ] and Ali Bu3 , were employed to catalyze the polymerization of allene derivatives under mild conditions. The Gd, Y, Tm, Lu metal based precursors exhibited distinguished 2,3-selectivity (>99.9 %) for phenylallene (PA) polymerization, whereas the smallest Sc metal based precursor showed a moderate 2,3-selectivity. The activity increased with the central metal size following the trend of Gd(5)>Tm(4)>Y(3)>Lu(2)>Sc(1). Moreover, Gd(5) also realized the purely 2,3-selective polymerizations of polar or nonpolar allene derivatives, para-methylphenylallene, para-flourophenylallene and para-methoxyphenylallene, regardless of electron-donating or -withdrawing substituents. Owing to the highly regular backbones, these polymers (except PPA) were crystalline, thus being the first crystalline polymers based on allene derivatives.