Cultural differences, oral mathematics and calculators in a teacher training course of the Brazilian Landless Movement

This paper discusses aspects of a two-year study of a teacher-training course for adult mathematics education organized by a Brazilian landless peoples' social movement. It takes ethnomathematics as a theoretical framework in which cultural differences are central. The paper analyses some of the oral mathematics practices that mark the landless peoples' culture studied. In particular, it discusses a pedagogical process involving the articulation of oral mathematics practices with the use of the calculator, focusing on how pre-service teachers give meaning to their experience and on how cultural differences operated in this setting.     

Solid‐State NMR of PEGylated Proteins

PEGylated proteins are widely used in biomedicine but, in spite of their importance, no atomic‐level information is available since they are generally resistant to structural characterization approaches. PEGylated proteins are shown here to yield highly resolved solid‐state NMR spectra, which allows assessment of the structural integrity of proteins when PEGylated for therapeutic or diagnostic use.     

Temperature‐Controlled Switchable Photochromism in Solid Materials

A novel strategy to achieve thermally switchable photochromism in solid materials is reported, which relies on the preparation of polymeric core–shell capsules containing solutions of photochromic dyes in acidic phase‐change materials. Upon changing the phase (solid or liquid) of the encapsulated medium, one of the two photochromic states of the system is selectively stabilized on demand, allowing for reversible interconversion between direct and reverse photochromism when thermally scanning through the melting temperature of the phase‐change material. This strategy, which does not require the addition of external agents or chemical modification of the dyes, proved to be general for different spiropyran photochromes and to be applicable to the fabrication of a variety of functional materials by simply embedding the capsules obtained into a solid matrix of choice.     

Chemoenzymatic preparation of nucleosides from furanoses

Chemoenzymatic preparation of ribose, deoxyribose and arabinose 5-phosphates was accomplished. These compounds were tested as starting materials in the enzymatic preparation of natural and modified purine and pyrimidine nucleosides, using an overexpressed Escherichia coli phosphopentomutase.