background: endodontic sealers usually come in contact with adjacent tissues and their biocompatibility is key in a successful treatment. the purpose of this study was to assess the cytotoxicity of three resin-based sealers, namely ah plus, endorez, and epiphany in set and fresh states on an l929 cell line. materials and methods: in this in vitro experimental study, the materials were mixed acc...

This paper was the response to a challenge set me as the senior historian of chemistry (in age) serving on the ACS National Historic Chemical Landmarks Committee. The challenge was to reflect on the history of chemistry in terms of the question posed in the paper’s title. Although there is a “tongue in cheek” quality to the question, it also has its serious side and it challenged me. I have to ...

I present calculations of soft and collinear corrections to the cross sections for single top quark production, and for Higgs production via bb̄ → H at the Tevatron and the LHC. I show that the corrections provide significant enhancements to the cross sections in both cases. For single top production the soft gluon corrections dominate the cross section, particularly in the s channel and in tW p...

We review the analysis of polarized structure function data using perturbative QCD at NLO. We use the most recent experimental data to obtain updated results for polarized parton distributions, first moments and the strong coupling. We also discuss several theoretical issues involved in this analysis and in the interpretation of its results. Finally, we compare our results with other similar an...

Teaching involves a search for meaning in the world. Teaching is a life project, a calling, a vocation that is an organizing center of all other activities. Teaching is past and future as well as present, it is background as well as foreground, it is depth as well as surface. Teaching is pain and humor, joy and anger, dreariness and epiphany. Teaching is world building, it is architecture and d...