The dominant kanr marker gene plays an important role in gene disruption experiments in budding yeast, as this marker can be used in a variety of yeast strains lacking the conventional yeast markers. We have developed a loxP-kanMX-loxP gene disruption cassette, which combines the advantages of the heterologous kanr marker with those from the Cre-lox P recombination system. This disruption cassette integrates with high efficiency via homologous integration at the correct genomic locus (routinely 70%). Upon expression of the Cre recombinase the kanMX module is excised by an efficient recombination between the loxP sites, leaving behind a single loxP site at the chromosomal locus. This system allows repeated use of the kanr marker gene and will be of great advantage for the functional analysis of gene families.

This paper addresses an innovative syntactic foam (SF) formed by counter-gravity infiltration of a packed bed of low-cost expanded perlite (EP) particles with molten A356 aluminium. The uniform distribution of EP particles in foams causes an even density throughout the height. Due to the low density (~0.18 g/cm 3) of EP, the average density of these foams is only 1.05 g/cm 3 which is considerably lower than most studied SFs. Owing to the high porosity of the filler material (~94%), the total porosity of the new foam reaches 61%. Microstructural observations reveal no sign of damage or unintended EP particle infiltration. EP shows a good wettability whilst essentially no reaction occurs at the EP-metal interface. Under compression, EP\A356 syntactic foam shows stress-strain curves consisting of elastic, plateau and densification regions. On account of its consistent plateau stress (average value 30.8 MPa), large densification strain (almost 60%), and high energy absorption efficiency (88%) EP\A356 syntactic foam is an effective energy absorber.

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