Uranium contamination of bivalve Mytilus galloprovincialis, speciation and localization

Uranium is a natural radioelement (also a model for heavier actinides), but may be released through anthropogenic activities. In order to assess its environmental impact in a given ecosystem, such as the marine system, it is essential to understand its distribution and speciation, and also to quantify its bioaccumulation. Our objective was to improve our understanding of the transfer and accumulation of uranium in marine biota with mussels taken here as sentinel species because of their sedentary nature and ability to filter seawater. We report here on the investigation of uranium accumulation, speciation, and localization in Mytilus galloprovincialis using a combination of several analytical (Inductively Coupled Plasma Mass Spectrometry, ICP-MS), spectroscopic (X ray Absorption Spectroscopy, XAS, Time Resolved Laser Induced Fluorescence Spectroscopy, TRLIFS), and imaging (Transmission Electron Microscopy, TEM, μ-XAS, Secondary Ion Mass Spectrometry, SIMS) techniques. Two cohorts of mussels from the Toulon Naval Base and the Villefranche-sur-Mer location were studied. The measurement of uranium Concentration Factor (CF) values show a clear trend in the organs of M. galloprovincialis: hepatopancreas ≫ gill > body ≥ mantle > foot. Although CF values for the entire mussel are comparable for TNB and VFM, hepatopancreas values show a significant increase in those from Toulon versus Villefranche-sur-Mer. Two organs of interest were selected for further spectroscopic investigations: the byssus and the hepatopancreas. In both cases, U(VI) (uranyl) is accumulated in a diffuse pattern, most probably linked to protein complexing functions, with the absence of a condensed phase. While such speciation studies on marine organisms can be challenging, they are an essential step for deciphering the impact of metallic radionuclides on the marine biota in the case of accidental release. Following our assumptions on uranyl speciation in both byssus and hepatopancreas, further steps will include the inventory and identification of the proteins or metabolites involved.

Frequency selective solutions for an efficient non-ionising radiation protection in the radiofrequency and microwave ranges

The paper introduces an efficient solution for the realisation of frequency-selective devices which can shield non-ionising radiation in the radiofrequency and microwave bandwidths. The identified hardware is transparent to visible light and it can be adapted to the shielding needs, both in terms of frequency and spatial behaviours. Being transparent, it can be effectively applied on windows that normally offer the worst attenuation coefficient to outdoor versus indoor penetration. The solution exhibits enhanced performance, it can be analysed with fast but exact numerical techniques and it can be manufactured by low-cost industrial procedures. To demonstrate the validity of the approach, an example has been designed, analysed and applied to the frequency spectrum occupied by upcoming wideband access base stations.

Neurofunctional effects in rats prenatally exposed to fluoxetine

In the treatment of depression fluoxetine [a selective serotonine reuptake inhibitor (SSRIs)] is a widely used drug in humans. The selectivity, efficacy, side effects and simplicity of dosage contributed to fluoxetine's clinical acceptance. Several psychiatric disorders (many of them responsive to SSRIs) are present during pregnancy; up to 10% of pregnant women fulfill diagnostic criteria for major or minor depression with an even higher percentage developing postpartum depression. Therefore, significant numbers of women may be taking SSRIs while pregnant. Since fluoxetine's safe use during pregnancy is not yet established and experimental studies inconclusive, we performed the present research in order to investigate the neurobehavioral effects produced in rats by prenatal exposure to fluoxetine (5 and 10 mg/kg/sc from day 13 to 20 of gestation) on cognitive functions, emotional reactivity and sexual performance.

Virtual musculo-skeletal model for the biomechanical analysis of the upper limb

In this paper, a musculo-skeletal model of the upper limb is presented. The limb is modelled as a three-dimensional 7 degrees-of-freedom system, linked to the shoulder, which has been considered as frame. The upper limb model is made up of four links corresponding to the most important body segments: the humerus, the ulna, the radius and the hand, considered as a single rigid body. Particular attention has been paid to the modelling of joints in order to mimic all the possible arm and forearm movements (including prono-supination). The model also includes 24 muscles. The mathematical model used to describe the muscles is that proposed by Zajac in 1989, modified by the authors. The kinematic analysis has been performed including an ergonomics index to take into account the posture and joint physical limits. Moreover an optimization criterion based on minimum activation pattern has been included in order to find muscular activation coefficients. The results of the proposed methodology concerning muscular activations have been compared to those coming from processed EMG signals, which have been acquired during experimental tests.

[Varix of the extra-hepatic portion of the fetal intra-abdominal umbilical vein: pathogenesis, prenatal sonographic diagnosis, and perinatal outcome]

AIM

Aim of the study was to investigate pathogenesis, diagnosis, and prognosis of the fetal intra-abdominal umbilical vein varix (FIUVV).

METHODS

We reviewed all cases of FIUVV diagnosed in our hospital from August 1999 to December 2002. The umbilical vein was considered dilated when the measurement was above 2 standard deviation of the mean for gestational age. In all cases prenatal echocardiography and post-natal karyotype were performed. Our cases were also considered in the light of all the cases of FIUVV reported in literature.

RESULTS

FIUVV was diagnosed in 5 cases between 22 and 37 weeks' gestation, among an unselected population of pregnant woman. Karyotype was normal in all cases; an apparently isolated septal ventricular defect was present in one patient. No obstetrical complications due to the presence of FIUVV (i.e. thrombosis) were associated.

CONCLUSIONS

In our case series no obstetrical complications, and only one mild fetal anomaly were present. In literature an high association has been reported between the presence of FIUVV and fetal anomalies and/or obstetrical complications. Fetal echocardiography and detailed US study of fetal anatomy is needed to exclude associated anomalies. Karyotype should be offered only when other fetal anomalies are present. In presence of FIUVV, a close fetal monitoring by serial color Doppler and ultrasonographic examinations should be performed.

[Effects on function of human lymphocytes exposed to electromagnetic fields with a frequency from 1,500 to 2,000 MHz]

Normal human peripheral blood lymphocytes were irradiated for 10 or 5 min with frequencies from 1.5 to 2.0 GHz. The frequency of 1.8 GHz overlaps that of mobile phones and leads to a significant reduction of the T-cell mediated antibacterial activity.

Kinetic properties of mitochondrial H+-adenosine triphosphatase in Morris hepatoma 3924A

A study of kinetic properties of mitochondrial ATPase in Morris hepatoma 3924A is reported. The results show that submitochondrial particles isolated from the tumor tissue exhibited a three-fold increase in both the Km for ATP hydrolysis and Ki for the competitive inhibitor [beta, gamma-imido]ATP with regard to normal rat liver. Eadie-Hofstee analysis of the kinetics of ATP hydrolysis show that both the high and the low affinity constants for ATP were enhanced in the hepatoma with respect to the rat liver enzyme. Kinetic analysis of passive proton conduction through the F0 sector of ATPase does not reveal any difference between Morris hepatoma and rat liver. In Morris hepatoma particles, 50% inhibition of the hydrolase activity required 10 times more oligomycin than in control particles. On the contrary, 50% inhibition of proton conduction occurred in both hepatoma and rat liver particles at the same concentration of oligomycin. It is concluded that in Morris hepatoma the catalytic process in F1 and the functional connection between F1 and F0 of the ATP synthase are altered with regard to control rat liver.

[Visco-elastic properties of various composites for the front teeth]

The rupture load, elasticity modulus and viscosity coefficient of certain composite currently on sale for the reconstruction of front teeth were calculated experimentally. The products examined were: Prismafil (Caulk), Helioprogress (Vivadent), Heliosit (Vivadent), Silux (3M), Concise (3M), Command Ultrafine (Kerr), P30 (3M). The figures obtained relate to 3 different time periods after the preparation of samples.

[Ionizing radiation and video computer terminals]

VDTs are more frequently being used and, therefore have given rise to the problem of security among operators exposed to possible X-ray emissions. The authors report the results of a dosimetric investigation, carried out through TLD CaF2:Dy on X-ray exposure levels close to video display terminals of a data processing center. After testing the exposure percentage values and the measurements adjusted to one-year basis, the authors report that the value are generally similar to those existing in the environment even though significant values have been found in a few cases.

The mechanism of transmembrane delta muH+ generation in mitochondria by cytochrome c oxidase

In rat liver mitochondria treated with rotenone, N-ethylmaleimide or oligomycin the expected alkalinization caused by proton consumption for aerobic oxidation of ferrocyanide was delayed with respect to ferrocyanide oxidation, unless carbonyl cyanide p-trifluoromethoxyphenylhydrazone was present. 2. When valinomycin or valinomycin plus antimycin were also present, ferricyanide, produced by oxidation of ferrocyanide, was re-reduced by hydrogenated endogenous reductants. Under these circumstances the expected net proton consumption caused by ferrocyanide oxidation was preceded by transient acidification. It is shown that re-reduction of formed ferricyanide and proton release derive from rotenone- and antimycin-resistant oxidation of endogenous reductants through the proton-translocating segments of the respiratory chain on the substrate side of cytochrome c. The number of protons released per electron flowing to ferricyanide varied, depending on the experimental conditions, from 3.6 to 1.5. 3. The antimycin-insensitive re-reduction of ferricyanide and proton release from mitochondria were strongly depressed by 2-n-heptyl-4-hydroxyquinoline N-oxide. This shows that the ferricyanide formed accepts electrons passing through the protonmotive segments of the respiratory chain at the level of cytochrome c and/or redox components of the cytochrome b-c1 complex situated on the oxygen side of the antimycin-inhibition site. Dibromothymoquinone depressed and duroquinol enhanced, in the presence of antimycin, the proton-release process induced by ferrocyanide respiration. Both quinones enhanced the rate of scalar proton production associated with ferrocyanide respiration, but lowered the number of protons released per electron flowing to the ferricyanide formed. 4. Net proton consumption caused by aerobic oxidation of exogenous ferrocytochrome c by antimycin-supplemented bovine heart mitochondria was preceded by scalar proton release, which was included in the stoicheiometry of 1 proton consumed per mol of ferrocytochrome c oxidized. This scalar proton production was associated with transition of cytochrome c from the reduced to the oxidized form and not to electron flow along cytochrome c oxidase. 5. It is concluded that cytochrome c oxidase only mediates vectorial electron flow from cytochrome c at the outer side to protons that enter the oxidase from the matrix side of the membrane. In addition to this consumption of protons the oxidase does not mediate vectorial proton translocation.