We found mutations in the gene PQBP1 in 5 of 29 families with nonsyndromic (MRX) and syndromic (MRXS) forms of X-linked mental retardation (XLMR). Clinical features in affected males include mental retardation, microcephaly, short stature, spastic paraplegia and midline defects. PQBP1 has previously been implicated in the pathogenesis of polyglutamine expansion diseases. Our findings link this gene to XLMR and shed more light on the pathogenesis of this common disorder

Microorganisms rule the functioning of our planet and each one of the individual macroscopic living creature. Nevertheless, microbial activity and growth status have always been challenging tasks to determine both in situ and in vivo. Microbial activity is generally related to growth, and the growth rate is a result of the availability of nutrients under adequate or adverse conditions faced by microbial cells in a changing environment. Most studies on microorganisms have been carried out under optimum or near-optimum growth conditions, but scarce information is available about microorganisms at slow-growing states (i.e., near-zero growth and maintenance metabolism). This study aims to better understand microorganisms under growth-limiting conditions. This is expected to provide new perspectives on the functions and relevance of the microbial world. This is because (i) microorganisms in nature frequently face conditions of severe growth limitation, (ii) microorganisms activate singular pathways (mostly genes remaining to be functionally annotated), resulting in a broad range of secondary metabolites, and (iii) the response of microorganisms to slow-growth conditions remains to be understood, including persistence strategies, gene expression, and cell differentiation both within clonal populations and due to the complexity of the environment.

Commercially pure iron powder has been processed by the capacitor electrical discharge consolidation technique. This consolidation technique applies an external pressure and, at the same time, heats a metallic powder mass by the Joule effect of a high-voltage and high-intensity electric current. In this work, a capacitor charged at low voltage has been used instead. The effect of the initial porosity of the Fe powder mass, i.e., of the precompaction pressure, and the number of discharges from the capacitor have been studied. The densification and remaining porosity, the sintering level, the Vickers microhardness, and the electrical resistivity of the sintered compacts have been studied. Compacts sintered by the conventional powder metallurgy route of cold pressing and furnace sintering were also prepared for comparison. Results show that a high initial porosity provides a high electrical resistance in the powder column, a necessary requisite for the Joule effect to increase densification with the number of discharges. Thus, the final porosity decreases to 0.22 after 50 discharges in the powder mass with an initial porosity of 0.30. With this initial porosity, the sintering process increases Vickers microhardness from 29 to 51 HV10 and decreases the electrical resistivity of the powder mass from 3.53 × 10−2 to 5.38 × 10−4 Ω·m. An initial porosity of 0.2 does not make the compacts densify, but a certain bond between particles is attained, increasing microhardness and decreasing electrical resistivity as the number of discharges increases. Lower initial porosities make the powder mass behave as an electrical conductor with no appreciable changes even after 50 electrical discharges.

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