In heap bioleaching, acidophilic extremophiles contribute to enhanced metal extraction from mineral sulphides through the oxidation of Fe(II) and/or reduced inorganic sulphur compounds (RISC), such as elemental sulphur or mineral sulphides, or the degradation of organic compounds derived from the ore, biota or reagents used during mineral processing. The impacts of variable solution acidity and...

A laboratory investigation was developed to confirm and to quantify the reductions in absorbable organic halide (AOX) discharge when sodium sulphide was added during elemental chlorine-free (ECF) bleaching of sugarcane bagasse pulp. After the chlorine dioxide bleaching stage, the pulp was sent directly into the extraction stage without washing. FTIR was employed to determine the breakage of che...

The utilization of several inorganic and organic sulphur compounds by three strains of Clostridium perfringens and the production of hydrogen sulphide from these compounds was investigated. Sulphate, sulphite, thiosulphate and sulphide cannot supply sulphur to the organism, neither do they have any effect, when added in non-toxic concentrations, on the growth in media containing utilizable orga...

It has been shown previously that antimony evaporated onto a Au(111) surface grows in a layer-bylayer mode. The present work compares the initial, fast-oxidation stage of these films with that on bulk polycrystalline antimony. Measurements were carried out in an ultrahigh-vacuum environment using Auger electron spectroscopy, low-energy electron diffraction, electron-energy-loss spectroscopy, an...

BACKGROUND The aim of this study was to observe the concentrations of trace metals boron, lithium, rubidium, antimony, tin and strontium in the serum of athletes from different modalities and sedentary subjects and the possible influence that different energy sports training modalities can have on their concentration. METHODS Eighty professional athletes and 31 sedentary males participated in...

Pentavalent antimonials, including meglumine antimoniate and sodium stibogluconate, have been used for more than half a century in the therapy of the parasitic disease leishmaniasis. Even though antimonials are still the first-line drugs, they exhibit several limitations, including severe side effects, the need for daily parenteral administration and drug resistance. The molecular structure of ...

Visceral leishmaniasis (VL) caused by the protozoan parasite Leishmania infantum, is one of the most important zoonotic diseases affecting dogs and humans in the Mediterranean area. The presence of infected dogs as the main reservoir host of L. infantum is regarded as the most significant risk for potential human infection. We have studied the susceptibility profile to antimony and other anti-l...

BACKGROUND Drug resistance is a major problem in leishmaniasis chemotherapy. RNA expression profiling using DNA microarrays is a suitable approach to study simultaneous events leading to a drug-resistance phenotype. Genomic analysis has been performed primarily with Old World Leishmania species and here we investigate molecular alterations in antimony resistance in the New World species L. amaz...

In previous and in work to be published, it has been shown that iron sulphide material, produced by sulphate-reducing bacteria (SRB), is an excellent adsorbent for a wide range of heavy metals. The material adsorbs between 100 and 400 mg g~1 and residual levels in solutions can be of the order of pg per litre. Further, strongly magnetic forms of this material can now be produced which can be e!...

Symbiotic associations between marine invertebrates and sulphur-oxidising bacteria are a common feature in communities from sulphide-rich environments, such as those flourishing in the vicinity of hydrothermal vents. While the bacterial endosymbionts provide the host with an undoubted nutritional advantage, their presence also requires specific adaptations for the transport and storage of sulph...