Operational functionalities of air-quality WSn metal-oxide sensors correlating semiconductor defect levels and surface potential barriers.

The comprehension of atmospheric pollution levels worldwide is a crucial issue for assessing the health consequences from human exposure to polluted air, and for identifying emission reductions that will be effective for minimizing the potential risks. Advanced interconnected sensors are required that could monitor on real-time toxic gaseous concentration. The success of these instruments depends on the reliability of these devices to quantify and disseminate the pollution levels to nearby citizens. Metal-oxide semiconductors are widely used as functional materials for gas sensing because of their chemo-resistive effect when interacting with gases. Mixed oxides are usually considered for the superior performances shown with respect to the single oxides. In this work, tungsten-tin mixed oxides with different Sn molar fraction (0.0018, 0.12, 0.33 and 0.89 named WS-1, WS-2, WS-3 and WS-4) were synthesized by sol-gel co-precipitation. The powders were characterized by ICP-OES analysis, specific surface area measurements, electron microscopy, X-ray diffraction, UV-Vis-NIR and FT-IR spectroscopies. The powders were also deposited through screen-printing technology, obtaining thick film gas sensors, on which measurements of conductance as a function of temperature, surface potential barrier and dynamical responses in the presence of oxidizing or reducing gases were carried out. Based on the studied properties, the mixed oxides can be divided into two groups: the WO3-like samples (WS-1, WS-2, WS-3) and the SnO2-like sample (WS-4). All samples present pure crystalline structures: this is a new result for the WO3-like samples. There is no literature data reporting about the introduction of so high Sn content in a WO3 structure. The combination of spectroscopic and electrical characterizations allowed the definition of an interpretative model that correlates the deepness of defect levels in the band gap of these materials to the values of the surface potential barrier in air and, as a consequence, to the electrical responses to oxidizing and reducing gases.

Dynamics of inorganic components in lake waters from Terra Nova Bay, Antarctica.

Water and Suspended Particulate Material (SPM) samples analysed in this work were collected in the austral summer 2011/12 from six shallow Antarctic lakes (Carezza, Edmonson Point 14 and 15a, Gondwana, Inexpressible Island 10b and Tarn Flat 20) of Terra Nova Bay (Northern Victoria Land, Antarctica). The total concentrations of a large suite of inorganic analytes were determined, in order to gain insight into the natural processes regulating species distribution, define natural background values and detect possible present or future local and/or global anthropogenic contamination. Lake water composition was found to be influenced by marine spray, lake geographical position and meltwater input. Seasonal variability was also evaluated for each analyte, and explained considering the natural transport processes involving each species. Multivariate chemometric techniques were used in order to identify groups of samples with similar characteristics and find out similarities and correlations among variables. The variability observed within the water samples is closely connected to the marine aerosol input; hence, it is primarily a consequence of geographical and meteorological factors, such as distance from the ocean and period of year. Higher element concentrations have been found in SPM than in water, suggesting that weathering plays an important role on the chemistry of these lakes or that adsorption processes take place. SPM samples were also examined with a Scanning Electron Microscope (SEM), and many diatoms belonging to different species were detected. No clear evidence of a relevant metal contamination was found in the investigated area.

An approach for arsenic in a contaminated soil: speciation, fractionation, extraction and effluent decontamination.

The fractionation and speciation of As in a contaminated soil were investigated, and a remediation strategy was tested. Regarding speciation, we found that As(V) prevails over As(III) whereas more than 40% of total arsenic is in organic form. The fractionation of As was investigated with two sequential extraction methods: a low mobility was found. Then we tested the possibility of using phosphoric acid to extract As from the soil and cleaning the washing effluents by sorption onto montmorillonite. The efficiency of the extraction and of the adsorption onto the clay were also investigated for Cr, Cu, Fe, Mn, Ni, Pb and Zn, whose total concentrations and fractionation in the soil are reported here. The extraction percentages for As and metals ranged from 30 to 65%; the residual proportions in the soil are presumably in very unreactive forms. Montmorillonite showed a good uptake capacity towards the investigated pollutants.

Adsorption of heavy metals on vermiculite: influence of pH and organic ligands.

The sorption behaviour of vermiculite has been studied with respect to cadmium, copper, lead, manganese, nickel, and zinc as a function of pH and in the presence of different ligands. The continuous column method was used in order to evaluate the feasibility to use the clay in wastewater purification systems. The total capacity of vermiculite was found to decrease in the following order: Mn > Ni > Zn > Cd > Cu > Pb. The adsorption of metal ions on vermiculite decreases with decreasing pH and increasing ionic strength. In general, the metal uptake on the clay was hindered by the presence of strong complexing agents in solution and it decreases with increasing of the complexation constants of the ligands with exception of cysteine and tiron. It is necessary, hence, to consider all these factors to effectively predict the uptake efficiency of this sorbent. However, it is possible to conclude that the vermiculite has good potentialities for cost-effective treatments of metal-contaminated wastewaters.

[A descriptive analysis of naratriptan use among migraineurs in ambulatory medicine]. / Analyse descriptive des modalités d'usage du naratriptan dans la prise en charge de la migraine en médecine de ville.

The objective of this study was to provide an epidemiological description of naratriptan use in ambulatory medicine. 1695 patients were recruited by 384 primary care physicians and 111 neurologists, and followed for 12 weeks. Physicians had to document the migraine history, and to report symptoms and health care in a structured case report form. Patients were to document each episode of migraine (EM) in a diary. At baseline, 45 p.cent of the patients reported their migraine treatment as unsatisfactory. Ninety-eight percent of included patients were migraineurs according to criteria of the International Headache Society (IHS), including migrainous disorders. Ninety-two percent of naratriptan prescriptions were established in the second intention in patients with migraine, according to the IHS classification, including migrainous disorders. A total of 79 p.cent of patients had complied with the good practices for all EMs. More appropriate health education strategies should target the small group of patients who over-use naratriptan, and patients with aura. However, this study shows that naratriptan tends to be correctly prescribed by physicians, and used by patients with acute migraine.

[Efficacy of and tolerance to prolonged release prazosin in patients with hypertension and non-insulin dependent diabetes]. / Etude de l'efficacité et de la tolérance de la prazosine à libération prolongée chez des patients hypertendus et diabétiques non insulinodépendants.

UNLABELLED: The treatment of hypertension represents one of the major elements of the cardiovascular prognosis in type II diabetes. Among antihypertensive drugs, alpha blockers may be interesting because of the absence of unfavourable effects on plasma glucose and lipid levels. OBJECTIVE: The aim of this study was to evaluate the effectiveness and the safety of prazosin osmotic tablet treatment in non-insulin-dependent diabetic patients with mild to moderate arterial hypertension. METHODS: After an initial 4-week-single-blind placebo period, 81 hypertensive subjects (162 +/- 11/96 +/- 5 mmHg) with type II diabetes were included in the study to receive prazosin osmotic tablet (o.t) open-label therapy at the dose of 2.5 mg/day for 12 weeks. After 4 weeks of treatment the dosage of prazosin o.t was increased to 5 mg/day if the diastolic blood pressure remained > or = 90 mmHg. RESULTS: Both supine and standing systolic and diastolic blood pressures were significantly decreased (P < 0.001) with prazosin therapy from 162 +/- 10/96 +/- 5 mmHg in supine and 160 +/- 12/95 +/- 6 mmHg in the upright position, to 149 +/- 15/86 +/- 9 mmHg and 148 +/- 16/86 +/- 9 mmHg respectively at the end of the 12-week-treatment period. There were no significant changes in the glycemic parameters (glycemia, haemoglobin A1c) during the prazosin therapy compared with baseline values. A significant decrease of triglycerides (P = 0.005), total cholesterol (P < 0.001) and LDL cholesterol (P = 0.03) levels was observed during prazosin therapy compared with the baseline measurements, whereas HDL cholesterol remained stable. Only 6% of the patients reported adverse events in relation with the study drug during the active treatment period. CONCLUSION: This study showed a significant decrease of the blood pressure in hypertensive subjects with type II diabetes after prazosin o.t treatment, without any change of glycemic parameters. Moreover, there was a favourable evolution of the lipidic parameters during the study characterised by a significant decrease of triglycerides and total and LDL cholesterol.

[Treatment of non-complicated acute cystitis in women: lomefloxacin versus pefloxacin]. / Traitement de la cystite aiguë non compliquée de la femme: loméfloxacine versus péfloxacine.

OBJECTIVES: Compare the acceptability of a 3-day regimen with that of a single-dose regimen of fluoroquinolones for the treatment of lower urinary tract infection in women. METHODS: A multicentric, randomized open trial was conduced in 595 patients by general practitioners to determine acceptability, efficacy and tolerance of lomefloxacine 400 mg in a once a day dose given for three days compared with a once-a-day 800 mg dose of pefloxacin for the treatment of lower urinary tract infection in women. RESULTS: The delay to symptom relief was greater than 24 hours in both treatment groups. Symptom relief was observed after treatment onset in only 23% of the patients. Clinical success rate at day 14 was 94.2% for lomefloxacin and 95.7% for pefloxacin. The rates of bacteriological eradication were 90.6% and 92.8% respectively with no significant difference. Adverse events were reported in 27.1% and 33.3% of the patients respectively, digestive disorders (abdominal pain, nausea) and neurosensorial disorders (headache, dizziness) predominated. There was no serious adverse event. The incidence of adverse events related to the treatment according to the investigator was smaller with lomefloxacin (16.1%) than with pefloxacin (23.5%) (p = 0.026). CONCLUSION: Acceptability, assessed at day 14, was not significantly different between the two treatment groups. Lomefloxacin was the only antibiotic currently authorized for use in a three-day regimen for the treatment of lower urinary tract infections.