Minimizing matrix effects and spectral interferences produced by Fe absorption lines in the determination of cadmium by electrothermal atomic absorption spectrometry: Application to the fractionation of cadmium in moderated contaminated soils

Solutions, including the extracting solutions used in the sequential procedure recommended by the Standard, Measurements and Testing Program, with different cadmium and iron concentrations were prepared and analyzed using combined electrothermal atomic absorption spectrometry (ETAAS) and two background compensation techniques. The first was based on the deuterium background correction method in which a deuterium lamp was used in combination with a conventional Cd hollow-cathode lamp. For the second, a high-intensity boosted discharge hollow-cathode lamp (BDHCL) was used as in the Smith–Hieftje (S–H) background correction method, but this lamp was modulated with a low and a high current mode at a modulation frequency of 100 Hz. In the present study, the modulation cycle was 10 times higher than in the S–H system. Therefore, the background correction method was called high-speed self-reversal method. Pseudo-total Cd concentrations were determined using ETAAS in five reference materials and fractionation was made in two reference soils. With regard to the results, the high-speed self-reversal background correction method provided a method of choice to eliminate or decrease the spectral interference due to the close positioning of the analytical lines of Cd and Fe in solutions containing high iron concentrations during the Cd determination by electrothermal atomic absorption spectrometry. It is worth noting that using the HSSR-method, the sensitivity losses were from 32% to 39% compared to the continuum source background corrector equipped with a deuterium lamp. The HSSR-method was successfully applied to the determination of Cd in contaminated samples. The results showed that interferences caused by absorption line overlapping of Cd and Fe could be compensated accurately for Fe/Cd = 100,000 in 0.11 M acetic acid and Fe/Cd < 10,000 in 0.5 M hydroxylamine hydrochloride.     

Antifibrotic and hemodynamic effects of the early and chronic administration of octreotide in two models of liver fibrosis in rats

The aim of this study was to assess the effect of the early and chronic administration of octreotide in the prevention of hepatic fibrosis and portal hypertension (PHT). Two experimental models of liver fibrosis caused by bile duct ligation (BDL) or CCl4 were divided into 4 rat groups: sham, placebo, and octreotide (10 and 100 micrograms/kg twice daily, subcutaneously). Liver fibrosis was assessed by the area of fibrosis (image analysis), liver hydroxyproline and fibronectin mRNA contents, and serum hyaluronate. Systemic and splanchnic hemodynamic changes were also evaluated, including the splenorenal shunt blood flow by the transit-time ultrasound (TTU) technique. In both models, splenorenal shunt blood flow was significantly lower in the octreotide groups than in the placebo group (P <.05), while portal pressure was not significantly decreased. There was a significant decrease in fibrosis by octreotide in the CCl4 model only: area of fibrosis: 13.9% +/- 3.7% vs. 9.8% +/- 2.5% (P <.01), hydroxyproline: 1.8 +/- 0.6 vs. 1.3 +/- 0.4 mg/g wet liver (P <.05), respectively, placebo vs. octreotide 10 micrograms/kg. There was a significant correlation between the area of fibrosis and hydroxyproline liver content (r =.87 in the biliary model and r =.91 in the CCl4 model; P <.0001). The early and chronic administration of octreotide prevents the development of portocollateral blood flow without reducing portal pressure in two models of liver fibrosis and the development of liver fibrosis in the CCl4 model.     

Fictive-Temperature Mapping in Highly Ge-Doped Multimode Optical Fibers

In this paper, a Fourier transform infrared focal-plane-array detector was used to image the "bond-stretching" vibration mode observed near sigma=1120 cm^-1 of highly Ge-doped graded-index multimode optical fibers (GI-MMFs). We show that the distribution of the peak wavenumber sigma is nonuniform across the core and cladding of the MMF, i.e., sigma is smaller in the core due to the Ge-doping. Next, as calibration curves between sigma and the fictive temperature T_f are not available in the literature for highly Ge-doped glasses (above 7w%), we have determined calibration curves from 1w% to 30w% in Ge. Then, we have applied these corrections in order to estimate, for the first time to our knowledge, the fictive-temperature distribution within multimode-fiber cross section. Using these curves, we show that T_f is higher at the fiber edges, presumably due to faster cooling. Furthermore, there is also a T_f increase in the center of the core (i.e., higher Ge content)     

Assessment of a remediation technique using the replacement of contaminated soils in kitchen gardens nearby a former lead smelter in Northern France

Vegetables cultivated in kitchen gardens that are strongly contaminated by heavy metals (Pb, Cd) may represent to consumers a means of exposure to these metals. This exposure is more problematic for those families that include a large quantity of home-grown vegetables in their diet. Researchers have shown that the majority of vegetables produced in kitchen gardens in the vicinity of the Metaleurop Nord smelter (Northern France) do not conform to European regulations. This study was carried out in three of these kitchen gardens. The concentrations of Cd and Pb in the topsoils were up to 24 and 3300 mg kg(-1) respectively. The method consisted of delineating a surface area of about 50 to 100 m(2) for each garden, then removing the contaminated soil and replacing it with a clean one. Seven species of vegetables were cultivated from 2003 to 2005 in the original contaminated soils and the remediated ones. The data showed a clear improvement of the quality of the vegetables cultivated in remediated soils, although 17% of them were still over the European legislative limits for foodstuffs. This suggested that there was a foliar contamination due to contaminated dust fallout coming from the closed smelter site and the adjacent polluted soils. In addition, the measurement of the Cd and Pb concentrations in the dust fallout showed that the substantial rise in metal concentrations in the remediated soil was not only due to atmospheric fallout. These results raise questions about possible technical, economic and sociological problems associated with this kind of remediation.     

Thermal stability of the 248-nm-induced presensitization process in standard H2-loaded germanosilicate fibers

Grating growths through exposure of presensitized standard fibers to KrF light were recorded in various experimental condition. It is shown that there exists an optimum sensitization fluence at which the efficiency of the sensitization process is higher. Isochronal thermal annealing of pre-exposed fibers led to a decrease in the sensitization-induced enhancement of photosensitivity. IR-absorption spectroscopy was carried out in fibers or preform plates to monitor the attenuation ascribed to H-bearing species in the same samples. The annealing-induced decay in photosensitivity cannot be correlated with those of the H-bearing species in the whole temperature range (110 degrees C-800 degrees C). This indicates that the enhancement of photosensitivity comes from the transformation of more than one species.     

Form-induced birefringence in elliptical hollow photonic crystal fiber with large mode area

We propose a novel type of photonic crystal fiber (PCF), including an elliptical hole in its solid core. We prove the feasibility of such a fiber and investigate both experimentally and theoretically the dependence of its group birefringence on the geometric hole parameters. We show, for the first time, that form-induced birefringence can be achieved in single mode PCFs with large mode area and suggest it as a possible route for the development of polarization maintaining PCF-based LMA fiber devices.     

Bilateral 3rd cranial nerve palsy disclosing oligodendroglioma

The patient was a 30 year-old man. He had no previous history. For several months he experienced a slowly progressive horizontal diplopia which was the expression of a bilateral third cranial nerve palsy with an intact intrinsic component. Muscular or neuro-muscular pathology as myasthenia was initially suspected but not confirmed. CT scan and MRI revealed an atypical left temporo-insular lesion which led us to discuss a chronic inflammatory pathology as sarcoidosis or a tumoral process. Finally cerebral biopsy showed a high grade oligodendroglioma. Symptomatology was attributed to infiltration of the peduncles from this tumor. Such a case has never been seen before. Early neuroradiological explorations would be useful in case of clinical suspicion of cranial nerve palsy.     

Antithrombin, protein C and protein S levels in 127 consecutive young adults with ischemic stroke

Children with spina bifida, cerebral palsy, mental retardation, developmental delays, and seizure states are handicapped with sensorimotor deficits, including gait or coordination instability, temperature insensitivity, and mental simplicity. These handicaps make this distinct and unpretentious population more susceptible to lethal burns. A 30-year review was conducted in a pediatric burn center to examine the relationships between pediatric sensorimotor deficit and burn injury. Of the 4874 acute burn admissions, 66 children were identified with preexisting sensorimotor deficits. Data indicate that children with sensorimotor deficit are more prone to burn injury from both their physical impairment and poorly supervised environments. In addition to extended hospitalizations, these children bear significantly higher mortality risks. Had the special supervisions and protection required by such handicapped children been provided, 80% of the burn injuries could have been prevented. Results emphasize that the future of these special children with sensorimotor deficits relies on health care providers playing a greater role in educating parents and caregivers.     

Progress in silica optical fibre photosensitivity

A comprehensive survey of photosensitivity in silica optical fibre is reviewed. Recent work on understanding the mechanisms contributing to germanium or aluminum doped fibre photosensitivity is discussed within the framework of the colour-center or photoelastic densification models.