Efficacy of sodium hypochlorite and chlorhexidine against Enterococcus faecalis: a systematic review

The efficacy of the sodium hypochlorite (NaOCl) and chlorhexidine (CHX) on Enterococcus faecalis was evaluated by systematic review and meta-analysis. The search strategies included search in electronic biomedical journal databases (MEDLINE, EMBASE, CENTRAL) and handsearching records, using different matches of keywords for NaOCl, CHX and Enterococcus faecalis. From 41 in vivo studies, 5 studies met the inclusion criteria. In a sample containing 159 teeth, E. faecalis was detected initially in 16 (10%) teeth by polymerase chain reaction (PCR) and 42 (26.4%) teeth by microbial culture techniques. After root canal disinfection, this species was observed in 11 (6.9%) teeth by PCR and 12 (7.5%) teeth by culture. Risk differences of included studies were combined as generic inverse variance data type (Review Manager Version 5.0 _ Cochrane Collaboration, http://www.cc-ims.net, accessed 15 May 2008), taking into account the separate tracking of positive and negative cultures/PCR. The level of statistical significance was set at p<0.05. In conclusion, NaOCl or CHX showed low ability to eliminate E. faecalis when evaluated by either PCR or culture techniques

Alkane Functionalization via Electrophilic Activation

Electrophilic activation, which may be defined as the substitution of a transition metal center for a proton to generate a new metal–carbon bond, is the basis of a number of promising approaches to selective catalytic functionalization of alkanes. The field was introduced by the groundbreaking chemistry exhibited by aqueous chloroplatinum complexes, reported by Shilov in the early 1970s. Since then the field has expanded greatly, and electrophilic alkane activation has been demonstrated using a wide variety of species. These include ligand-supported platinum complexes; complexes of additional late transition metals, most commonly palladium but also iridium, gold and others; and even post-transition metals such as mercury. That body of work is surveyed here, with particular emphasis on mechanistic understanding, examples of actual functionalization at sp^3-hybridized C–H bonds in alkanes and related compounds, and assessment of the further development that will be needed for practical applications