First insight into the natural biodegradation of cyanide in a gold tailings environment enriched in cyanide compounds.

The disposal of mining wastes that contain cyanide are dumped in tailings from gold extraction is a public concern in mining countries such as South Africa. Many studies have shown the potential of microorganisms to degrade cyanide. However, no in-situ exploration, in tailings contaminated with cyanide, of the capability of indigenous microorganisms to act as a natural barrier for cyanide attenuation has been performed.

Cyanide within gold mine waste of the free state goldfields: A geochemical modelling approach.

Cyanide, which remains the preferred chemical used in the gold extraction process, has the potential to be disposed of on goldmine tailings. South Africa has nine goldfields, producing approximately a third of the world's gold to date. The cyanide interacts with metals in the tailings environment, where Prussian blue [Formula: see text] and Turnbull's blue [Formula: see text] are among these.

Slender salamanders (genus ) reveal Southern California to be a center for the diversification, persistence, and introduction of salamander lineages.

Background: The southern California biodiversity hotspot has had a complex geological history, with both plate tectonic forces and sea level changes repeatedly reconfiguring the region, and likely driving both lineage splittings and extinctions. Here we investigate patterns of genetic divergence in two species of slender salamanders (Plethodontidae: ) in this region. The complex geological history in combination with several organismal traits led us to predict that these species harbor multiple ancient mitochondrial lineages endemic to southern California.

A high magnification UV lens for high temperature optical strain measurements.

Digital Image Correlation (DIC) measures full-field strains by tracking displacements of a specimen using images taken before and after deformation. At high temperatures, materials emit light in the form of blackbody radiation, which can interfere with DIC images. To screen out that light, DIC has been recently adapted by using ultraviolet (UV) range cameras, lenses, and filters.

Exploring Chihuahuan Desert diversification in the gray-banded kingsnake, Lampropeltis alterna (Serpentes: Colubridae).

Within many biomes, the cause of phylogeographic structure remains unknown even across regions throughout North America, including within the biodiverse Chihuahuan Desert. For example, little is known about population structure or the timing of diversification of Chihuahuan endemics. This is due largely to the lack of population genomic studies within this region.

OH production from the photolysis of isoprene-derived peroxy radicals: cross-sections, quantum yields and atmospheric implications.

In environments with high concentrations of biogenic volatile organic compounds and low concentrations of nitrogen oxides (NO = NO + NO), significant discrepancies have been found between measured and modeled concentrations of hydroxyl radical (OH). The photolysis of peroxy radicals from isoprene (HO-Iso-O) in the near ultraviolet represents a potential source of OH in these environments, yet has not been considered in atmospheric models. This paper presents measurements of the absorption cross-sections for OH formation (σ) from the photolysis of HO-Iso-O at wavelengths from 310-362.

Collagen scaffold meniscus implant integration in a canine model: a histological analysis.

In the situation of an irreparable meniscus tear, an implant comparable to a normal meniscus is an attractive option. Using a canine model, we assessed the early and late histologic response to a tissue engineered meniscal collagen scaffold (CS). All animals received bilateral arthrotomies, and all joints receiving the CS had an 80% resection of the meniscus.

The human knee meniscus: a review with special focus on the collagen meniscal implant.

The human knee meniscus is important for the protection of the knee joint from degeneration. Because it is so commonly injured, several methods have been developed to replace damaged meniscal tissue with either transplanted menisci or other synthetic implants. Here we review these different approaches, with a clinical and histological focus on the collagen meniscal implant (CMI or Menaflex), a tissue-engineered bovine collagen product.

Effects of fertilization and fungal and insect attack on systemic protein defenses of austrian pine.

Despite their economic and ecological importance, defense responses of conifers to pests are little understood. In a 3-year experiment, we monitored systemic fungal (Diplodia pinea)- and insect (Neodiprion sertifer)-induced defense protein activities and total soluble proteins in needles and phloem of Austrian pine (Pinus nigra) across a soil fertility gradient. In both years, total soluble protein content of foliage and phloem declined with increasing fertility across induction treatments, while defensive protein activities generally increased with increasing fertility.

Partial phase synchronization of neural populations due to random Poisson inputs.

We show that populations of identical uncoupled neurons exhibit partial phase synchronization when stimulated with independent, random unidirectional current spikes with interspike time intervals drawn from a Poisson distribution. We characterize this partial synchronization using the phase distribution of the population, and consider analytical approximations and numerical simulations of phase-reduced models and the corresponding conductance-based models of typical Type I (Hindmarsh-Rose) and Type II (Hodgkin-Huxley) neurons, showing quantitatively how the extent of the partial phase synchronization depends on the magnitude and mean interspike frequency of the stimulus. Furthermore, we present several simple examples that disprove the notion that phase synchrony must be strongly related to spike synchrony.

Testing the growth-differentiation balance hypothesis: dynamic responses of willows to nutrient availability.

Here, the growth-differentiation balance hypothesis (GDBH) was tested by quantifying temporal variation in the relative growth rate (RGR), net assimilation rate (NAR), and phenylpropanoid concentrations of two willow species (Salix sericea and Salix eriocephala) across five fertility levels. Initially, RGR increased and total phenylpropanoids declined (although every individual phenolic did not) as fertility increased, but NAR was unaffected. Subsequently, NAR and phenylpropanoids declined in the low fertility treatment, generating a quadratic response of secondary metabolism across the nutrient gradient.

The effect of collagenase and hyaluronidase on transient perfusion in human osteosarcoma xenografts grown orthotopically and in dorsal skinfold chambers.

Background: Collagenase and hyaluronidase are enzymes which degrade the extracellular matrix and increase the uptake and improve the distribution of therapeutic macromolecules in tumours. The purpose of the present work was to investigate whether collagenase or hyaluronidase had any effects on transient perfusion and/or changes in vascular areas.

Materials And Methods: The effects were studied in human osteosarcomas in BALB/c nu/nu mice growing orthotopically around and infiltrating the femurs, and in dorsal skinfold chambers using confocal laser scanning microscopy.

Cross-induction of systemic induced resistance between an insect and a fungal pathogen in Austrian pine over a fertility gradient.

Evidence for cross-induction of systemic resistance or susceptibility in plant-fungus-herbivore interactions is mostly derived from herbaceous model systems and not perennial woody plants. Furthermore, the effects of environmental variables such as soil fertility on these tripartite interactions are generally unknown. This study examined cross-induction of systemic resistance in Pinus nigra (Austrian pine) to infection by Sphaeropsis sapinea (a fungal pathogen), or feeding by Neodiprion sertifer (European pine sawfly), by prior induction with either S.

Enzymatic O-methylation of flavanols changes lag time, propagation rate, and total oxidation during in vitro model triacylglycerol-rich lipoprotein oxidation.

3'-O-Methyl derivatives of flavan-3-ols, (+)-catechin (C), (-)-epicatechin (EC), and (-)-catechin gallate (CG) were prepared enzymatically. Hexanal (EC and CG family, 5 mmol/L) and conjugated diene (C and EC family, 0.25-10 mmol/L) formation following CuSO4-mediated triacylglycerol-rich lipoprotein oxidation was measured.

Effects of drought stress and nutrient availability on dry matter allocation, phenolic glycosides, and rapid induced resistance of poplar to two lymantriid defoliators.

The growth-differentiation balance hypothesis (GDBH) postulates that variation in resource availability can increase or decrease allocation to secondary metabolism, depending on how growth is affected relative to carbon assimilation. Growth and leaf area of black poplar (Populus nigra) increased substantially in response to increased nutrient availability, while net assimilation rate and photosynthesis were less strongly affected. In response, total phenolic glycoside concentrations declined, which is consistent with GDBH.