Molecular responce of Atlantic cod's (Gadus morhua L.) cypia, prolactin and Zona radiata genes upon exposure to polychlorinated biphenyls

A molecular response study was conducted to determine whether Polychlorinated Biphenyl or PCB (Clophen A40) had an effect on the induction of the zona radiata, prolactin and cytochrome P4501A (CYP1A) mRNAs in matured Atlantic cod (Gadus morhua). A total of 127 fishes were maintained under natural photoperiod in tanks and fed with wet pellets containing Clophen A40. RNA samples were taken from the gonads, pituitary and the liver from day 0, 48 and 105 after sacrificing the fish and stored at -20OC prior to analysis. Analysis of gene induction by Northern hybridization assay showed the induction of prolactin and CYP1A in the pituitary and the liver tissues respectively after PCB treatment. The induction was found to be sex, age and seasonal specific. Males had greater gene expression than the females. There was however, no observed differences between the controlled and exposed fishes in terms of zona radiata gene expression. Although the picture is far from complete, the findings demonstrate the potential of using gene induction as a biomarker of aquatic pollution.Keywords: Cytochrome P4501A, Biomarker, Gene expressio

Spectral fluctuations of tridiagonal random matrices from the beta-Hermite ensemble

A time series delta(n), the fluctuation of the nth unfolded eigenvalue was recently characterized for the classical Gaussian ensembles of NxN random matrices (GOE, GUE, GSE). It is investigated here for the beta-Hermite ensemble as a function of beta (zero or positive) by Monte Carlo simulations. The fluctuation of delta(n) and the autocorrelation function vary logarithmically with n for any beta>0 (1<<n<<N). The simple logarithmic behavior reported for the higher-order moments of delta(n) for the GOE (beta=1) and the GUE (beta=2) is valid for any positive beta and is accounted for by Gaussian distributions whose variances depend linearly on ln(n). The 1/f noise previously demonstrated for delta(n) series of the three Gaussian ensembles, is characterized by wavelet analysis both as a function of beta and of N. When beta decreases from 1 to 0, for a given and large enough N, the evolution from a 1/f noise at beta=1 to a 1/f^2 noise at beta=0 is heterogeneous with a ~1/f^2 noise at the finest scales and a ~1/f noise at the coarsest ones. The range of scales in which a ~1/f^2 noise predominates grows progressively when beta decreases. Asymptotically, a 1/f^2 noise is found for beta=0 while a 1/f noise is the rule for beta positive.Comment: 35 pages, 10 figures, corresponding author: G. Le Cae

Foraging ecology of the South Australian glossy black-cockatoo ( Calyptorhynchus lathami halmaturinus )

The endangered South Australian glossy black-cockatoo ( Calyptorhynchus lathami halmaturinus Mathews 1912) feeds almost exclusively on the seeds of the drooping sheoak ( Allocasuarina verticillata ), and shows marked preferences for individual trees. This field study investigated foraging ecology and tree selection through observations of foraging birds and measurements of trees and seed cones. The cockatoos spent the vast majority of their foraging time (94%) handling seed cones, and handling behaviour was highly stereotyped. Handling time per cone was correlated primarily with cone size, while seed intake rate was correlated primarily with seed mass per cone. The cockatoos fed mostly in trees with signs of previous feeding. They tended initially to sample trees with large seeds, and to stay for long feeding bouts in trees with high ratios of seed-to-cone mass. As a result of these biases, feeding was concentrated in trees with high seed mass per cone. Preferred trees were also larger, with higher ratios of seed-to-cone mass and larger seeds containing more lipid and protein. By feeding from selected trees the cockatoos increased both their seed intake rate and the nutritional quality of the seeds ingested, thereby increasing their energy intake rate by an estimated 28%. They did not discriminate against trees that had re-grown from basal shoots after fires. Insect larvae were present in some seed cones but the cockatoos did not appear to actively seek them. Males foraged 19% more efficiently than females, resulting in greater daily food intake. The characteristics of individual A. verticillata trees that determined the cockatoos' feeding rates were also correlated with their distribution on a regional scale. This suggests that the distribution of this endangered cockatoo depends not only on the presence of food trees, but also on their regionally varying feeding profitability.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/72786/1/j.1442-9993.2000.tb00003.x.pd

A laterally-fused N-heterocyclic carbene framework from polysubstituted aminoimidazo[5,1-b]oxazol-6-ium salts

A polysubstituted 3-aminoimidazo[5,1-b]oxazol-6-ium framework has been accessed from a new nitrenoid reagent by a two-step ynamide annulation and imidazolium ring-formation sequence. Metalation with Au(I), Cu(I) and Ir(I) at the C2 position provides an L-shaped NHC ligand scaffold that has been validated in gold-catalysed alkyne hydration and arylative cyclisation reactions

Numerical reconstruction of brain tumours

We propose a nonlinear Landweber method for the inverse problem of locating the brain tumour source (origin where the tumour formed) based on well-established models of reaction–diffusion type for brain tumour growth. The approach consists of recovering the initial density of the tumour cells starting from a later state, which can be given by a medical image, by running the model backwards. Moreover, full three-dimensional simulations are given of the tumour source localization on two types of data, the three-dimensional Shepp–Logan phantom and an MRI T1-weighted brain scan. These simulations are obtained using standard finite difference discretizations of the space and time derivatives, generating a simple approach that performs well

Synthesis of atropisomeric phosphino-triazoles and their corresponding gold(i) complexes

The synthesis of atropisomeric phoshino-triazoles is disclosed. It was found that the introduction of a phosphine functionality onto the 5-position of a 1,2,3-triazole ring could be highly restrictive towards the rotation around a triazole-aryl bond. VT NMR and chiral HPLC studies demonstrated that rotation was restricted even at high temperatures. Gold(I) chloride complexes of single-enantiomer phosphines were prepared and again demonstrated to be conformationally stable

Intracranial halo pin penetration causing brain injury secondary to poor halo care technique: a case report and literature review

This is a case report of intra cranial penetration by halo pins resulting in cerebritis and fits secondary to incorrect halo care by the patient and his family. Halo pin penetration into the skull with brain injury is itself a rare incident. Previously documented case reports were in patients with a previous cranioplasties and they were highlight the fact that halo not to be used in cranioplasty patients. Cranial penetration of the halo pins has generally been secondary to a fall/medical condition as epilepsy. This incident how ever highlights the fact the halo care itself along with proper techniques used for tightening the halo pins by the carer plays a crucial role in preventing complications such as this