Copper-Decorated Titanium Electrodes: Impact of Surface Modifications of Substrate on the Morphology and Electrochemical Performance

This study investigates the effect of surface modifications of the titanium substrate on the growth of electrochemically deposited copper. These materials are intended to serve as cathodes in the electroreduction of nitrates in aqueous solutions. Surface modifications included the use of hydrogen fluoride for titanium etching and anodization to promote the growth of a structured titania nanotube array. The effect of an intermediate calcination step for the nanotubes before deposition was assessed along with a comparison to an untreated substrate electrode. The materials were comprehensively characterized by SEM, XRD, contact angle, potentiodynamic tests, EIS, and cyclic voltammetry. Their electrocatalytic ability was tested in the reduction of aqueous solutions containing nitrates. The results reveal that surface finishing impacted the shape and size of the Cu microparticles, as well as the nucleation mechanism enabling a crystal-facet-controllable synthesis. All the materials exhibited microsized copper particles with a spherical shape with some clusters. On the etched titanium surface, a high number of heterogeneous submicroscopic particles were also present. The thermally treated anodized substrate promoted the development of a combination of sparse microparticles corresponding to defect sites in amorphous titanium and the presence of a diffuse coating of octahedral nanosized particles whose growth was promoted by the tetragonal structure of anatase crystals. Electrochemical tests display reduced charge transfer resistance upon copper deposition on the modified substrates, which is indicative of the enhanced conductivity of the coated materials. Additionally, cyclic voltammetry and electrolysis experiments reveal the electrodes' potential for nitrate reduction, showing a better response for the etched titanium substrate (30% nitrate removal, after 2 h at 25 mA cm-2).

Facile and Bioinspired Approach from Gallic Acid for the Synthesis of Biobased Flame Retardant Coatings of Basalt Fibers

A sustainable, bioinspired approach to functionalize basalt fibers with an innovative gallic acid (GA)-iron phenyl phosphonate complex (BF-GA-FeP), for the purpose of improving the flame retardancy in composite materials, is developed. BFs were at first pretreated with O3, obtaining surface free hydroxyl groups that allowed the subsequent covalent immobilization of biosourced GA units on the fiber through ester linkages. Phenolic -OH groups of the GA units were then exploited for the complexation of iron phenyl phosphonate, resulting in the target-complex-coated BF fiber (BF-GA-FeP). Microwave plasma atomic emission spectroscopy and scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy analyses of BF-GA-FeP highlighted an increase in iron content, modification of fiber morphology, and occurrence of phosphorus, respectively. BFs, modified with a low amount of the developed complex, were used to reinforce a poly(lactic acid) (PLA) matrix in the production of a biocomposite (PLA/BF-FeP). PLA/BF-FeP showed a higher thermal stability than neat PLA and PLA reinforced with untreated BFs (PLA/BF), as confirmed by thermogravimetric analysis. The cone calorimeter test highlighted several advantages for PLA/BF-FeP, including a prolonged time to ignition, a reduced time to flame out, an 8% decrease in the peak heat release rate, and a 15% reduced fire propagating index compared to PLA/BF.

Stigmatizing attitudes toward Internet gaming disorder, Problematic smartphone use and Problematic social networking site use: An experimental vignette study

Public stigma on substance and gambling disorders have been well documented. Negative effects of stigma include shame, embarrassment, fear being judged and the determent of help-seeking behaviors among stigmatized individuals. Less is known about the public perception toward Internet gaming disorder (IGD) and other widespread problematic behaviors that share some characteristics with established behavioral addictions, such as Problematic smartphone use (PSU) and Problematic social networking sites use (PSNSU). The purpose of this study is to compare the public perception of problematic Internet gamers, problematic smartphone users and problematic social networking sites users using an experimental within-group vignette study design. A sample of 280 adults (F = 72.1%; M_age = 32.84, SD = 13.85) was recruited and completed the study online. Participants were presented with male OR female vignettes (i.e. the gender of the target in the vignette was randomized) describing an individual with IGD, PSU, and PSNSU. A repeated-measures ANOVA followed by post hoc tests using Bonferroni's correction was used. IGD was seen as more serious, more noticeable, and less understandable than both PSU and PSNU. Moreover, participants' emotional reaction (e.g., anger and sadness) and desired social distance were significantly stronger toward IGD. However, vanity attributions were higher for individuals with PSNSU, which were also more blamed compared to both IGD and PSU. PSU was seen as more controllable than both IGD and PSNSU. The results, taken together, suggest that IGD is perceived as more inherently problematic, but PSNSU also seem to deserve scientific attention as individuals showing symptoms of PSNSU are blamed more than problematic Internet gamers. Our findings provide initial information that can be used when developing interventions to impact stigma toward technological addictions.

Effect of Precursors on the Electrochemical Properties of Mixed RuOx/MnOx Electrodes Prepared by Thermal Decomposition

Growing thin layers of mixed-metal oxides on titanium supports allows for the preparation of versatile electrodes that can be used in many applications. In this work, electrodes coated with thin films of ruthenium (RuOx) and manganese oxide (MnOx) were fabricated via thermal decomposition of a precursor solution deposited on a titanium substrate by spin coating. In particular, we combined different Ru and Mn precursors, either organic or inorganic, and investigated their influence on the morphology and electrochemical properties of the materials. The tested salts were: Ruthenium(III) acetylacetonate (Ru(acac)₃), Ruthenium(III) chloride (RuCl₃·xH₂O), Manganese(II) nitrate (Mn(NO₃)₂·4H₂O), and Manganese(III) acetylacetonate (Mn(acac)₃). After fabrication, the films were subjected to different characterization techniques, including scanning electron microscopy (SEM), polarization analysis, open-circuit potential (OCP) measurements, electrochemical impedance spectroscopy (EIS), linear sweep voltammetry (LSV), cyclic voltammetry (CV), and galvanostatic charge-discharge (GCD) experiments. The results indicate that compared to the others, the combination of RuCl₃ and Mn(acac) produces fewer compact films, which are more susceptible to corrosion, but have outstanding capacitive properties. In particular, this sample exhibits a capacitance of 8.3 mF cm^-2 and a coulombic efficiency of higher than 90% in the entire range of investigated current densities.

Pyrolysis wastewater treatment by adsorption on biochars produced by poplar biomass

Pyrolysis is a widely studied thermochemical process, however the disposal of the produced byproducts is an unexplored field. In particular, the acqueous phase, characterized by a high organic load (TOC), must be necessarily treated. Aims of this work is to study the potentiality of biochar as adsorbent material for the treatment of this wastewater. For this aim, pyrolysis wastewater and biochar produced in the same plant were used. Two biochars produced at different temperatures (550 and 750 °C) and an activated biochar produced by chemical activation with NaOH of the raw biomass were tested. The study shows that higher temperature in the biochar production leads to higher sorption capacity of the organic compounds due to an increase of the surface area. The activation process further increases the surface area of the biochar that becomes similar to that of a commercial activated carbon while the sorption capacity exceeds that of commercial activated carbon of 2.5 times.

Tetrachloroethene recovery and hazard reduction of spent powders from dry cleaning process

Dry cleaning facilities using perchloroethylene produce a solid waste consisting of spent filtering powders with a high content of residual perchloroethylene, together with dyes and non-volatile residues. Untreated spent powders, classified as hazardous waste, cannot be disposed in landfill and incineration represents the only viable alternative. In this study, together with a full characterisation of the waste, the removal and recovery of the residual perchloroethylene by means of different heat treatments was investigated. In particular, tests of distillation and stripping with air and steam were carried out, evaluating the effectiveness of the treatments by quantifying the residual perchloroethylene in the samples treated. The results obtained show that the spent filtering powders contained about 25% wt. of perchloroethylene and that the maximum perchloroethylene recovery was obtained by steam stripping; approximately 98% after only 50 minutes. However, this treatment accounted for the production of a liquid mixture containing perchloroethylene and of a solid waste that required a further washing with boiling water to decrease the residual organic content below the eligibility criteria for landfill disposal.

Environmental effects of using chelating agents in polluted sediment remediation

The results of laboratory scale experimental tests of contaminant extraction from marine sediment slurries are presented and discussed. The objective of this study was to compare the effectiveness of EDTA and rhamnolipid in copper removal from an artificially contaminated sediment. The comparison was made in terms of metal extraction yield, and in the evaluation of its mobilization towards the more exchangeable fractions in the sediment. Results show that, under acidic conditions established during washing, EDTA ensured higher extractions efficiencies of Cu (up to 95 %) than rhamnolipid, although there was less mobilization into bioavailable forms with the use of rhamnolipid. In addition, in the view of a biological treatment of the spent solution, the use of rhamnolipid resulted in a lower decrease of the specific oxygen uptake rate with respect to EDTA. In fact, the low surfactants concentration required, partially compensated the toxic effect of Cu towards biomass.

Transversus abdominis plane block for analgesia after Cesarean delivery. A systematic review

Cesarean delivery is a major surgical procedure, after which a woman can experience substantial postoperative discomfort or pain. Inadequate postoperative analgesia is one of the most common reasons for poor patient satisfaction following cesarean delivery. Although spinal or systemic opioids are currently the gold standard to achieve effective analgesia, they are often associated with side effects. In the last few years there has been growing interest in abdominal plane blocks, with promising data on their efficacy. The transversus abdominis plane (TAP) block is a regional analgesic technique which is gaining acceptance in postoperative analgesia for lower abdominal surgeries. In this systematic review of articles published as of 31 December 2013, we searched the principal medical databases for randomized controlled trials that assessed the efficacy of ultrasound (US)-guided TAP block following cesarean delivery and reported on postoperative opioid consumption and pain score, opioid-related side-effects and patient satisfaction. Although controversy surrounds the utility of US-guided TAP block in cesarean section, evidence suggests that when correctly executed as part of a multimodal analgesic regimen, TAP block may reduce postoperative opioid consumption and opioid-related side effects, improving postoperative pain control and patient satisfaction. Further studies are necessary to explore this field of research.

Hexavalent chromium reduction in contaminated soil: A comparison between ferrous sulphate and nanoscale zero-valent iron

Iron sulphate (FeSO4) and colloidal nano zero-valent iron (nZVI) as reducing agents were compared, with the aim of assessing their effectiveness in hexavalent chromium [Cr(VI)] removal from a contaminated industrial soil. Experiments were performed on soil samples collected from an industrial site where a nickel contamination, caused by a long-term productive activity, was also verified. The influence of reducing agents amount with respect to chromium content and the effectiveness of deoxygenation of the slurry were discussed. The soil was fully characterized before and after each test, and sequential extractions were performed to assess chemico-physical modifications and evaluate metals mobility induced by washing. Results show that both the reducing agents successfully lowered the amount of Cr(VI) in the soil below the threshold allowed by Italian Environmental Regulation for industrial reuse. Cr(VI) reduction by colloidal nZVI proved to be faster and more effective: the civil reuse of soil [Cr(VI)<2mg/kg] was only achieved using colloidal nZVI within 60min adopting a nZVI/Cr(VI) molar ratio of 30. The reducing treatment resulted in an increase in the amount of chromium in the oxide-hydroxide fraction, thus confirming a mechanism of chromium-iron hydroxides precipitation. In addition, a decrease of nickel (Ni) and lead (Pb) content in soil was also observed when acidic conditions were established.

Anaesthesia Management in Patients with Multiple Chemical Sensitivity Syndrome

Multiple Chemical Sensitivity (MCS) is characterised by the appearance of numerous and sometimes severe symptoms, when subjects are in contact with various chemicals and medicinal substances. Currently there are no useful guidelines for managing clinical issues and, specifically, anaesthesia for patients with MCS. This case report describes anaesthesia management in a patient affected by clinically documented MCS and a latex allergy, a candidate for a laparoscopic cholecystectomy operation.

Ghrelin and obestatin in infants, lactating mothers and breast milk

AIM

To investigate the role of ghrelin and obestatin in infancy.

METHODS

We measured ghrelin and obestatin concentrations in blood samples of infants, lactating mothers, and in breast milk.

RESULTS

The median (interquartile range) serum ghrelin concentrations were 922.11 (868.44) pg/ml in infants, 667.88 (942.78) pg/ml in lactating mothers, and 526.4 (439.86) pg/ml in breast milk. The serum obestatin levels were 844.87 (805.14) pg/ml in infants, 759.105 (855.55) pg/ml in lactating mothers, and 846.6 (472.07) pg/ml in breast milk. A positive correlation was found for serum ghrelin concentrations in breastfed infants and lactating mothers (p < 0.001, r = 0.789), serum ghrelin concentrations in breastfed infants and in breast milk (p < 0.001, r = 0.581), serum ghrelin concentrations in lactating mothers and in breast milk (p = 0.021, r = 0.450), and serum obestatin concentrations in breastfed infants and in lactating mothers (p = 0.047, r = 0.609).

CONCLUSION

We report for the first time the serum obestatin concentrations in infants and confirm the presence of correlations between ghrelin and obestatin in lactating mothers and breast milk. The correlations found early in infants' life, when hormones begin to exert their effects on feeding behavior, suggest that they may be involved in these processes.

Adiponectin in breast milk: relation to serum adiponectin concentration in lactating mothers and their infants

AIMS

  The aims of the study were to determine human breast milk adiponectin concentration and to investigate its relationship with serum adiponectin concentration in lactating mothers and their infants and also to evaluate the relationship between serum adiponectin concentration and anthropometric parameters in nurses and infants.

METHODS

  We enrolled 60 healthy term breastfed (BF) infants and their lactating mothers. Adiponectin was determined by radioimmunoassay test in serum and by enzyme-linked immunosorbent assay test in human milk (HM). Infants' and mothers' anthropometric parameters were measured.

RESULTS

  Median (25‰, 75‰) adiponectin concentration in HM was 9.99 (3.59, 20.52) ng/mL. Serum adiponectin concentration in infants was 60.49 (45.76, 74.24) μg/mL and in lactating mothers 21.14 (12.61, 29.66) μg/mL. Adiponectin concentration in HM correlated positively with adiponectin in mothers' serum; r = 0.60 (p < 0.001) and in infants' serum r = 0.37 (p = 0.015). Adiponectin in HM correlated negatively with infants' age r = -0.3 (p = 0.04). Infants' serum adiponectin correlated negatively with their weight r = -0.35 (p = 0.005), length r = -0.35 (p = 0.006) and age r = -0.46 (p < 0.001) and mothers' serum adiponectin with their weight r = -0.37 (p = 0.02) and body mass index r = -0.45 (p = 0.004).

CONCLUSIONS

  The observed correlations between adiponectin in mothers, HM and BF infants may be suggestive for a metabolic link between nurses and infants through milk.

PLZF-mediated control on c-kit expression in CD34(+) cells and early erythropoiesis

The promyelocytic leukemia zinc-finger protein (PLZF) is a transcription factor and c-kit is a receptor tyrosine kinase associated with human disease, particularly in hematopoietic cells. MicroRNAs (miRs) are post-transcriptional regulators of gene expression, and c-kit has been described as a target of miRs-221 and -222 in erythropoiesis. In the present study, we identified c-kit as a target of PLZF in normal and leukemic cells. Particularly, in erythropoietic (E) culture of CD34(+) progenitors, PLZF is downregulated, whereas c-kit expression at both the mRNA and protein levels inversely increases during the first days of E differentiation. In functional experiments, PLZF transfection induces c-kit downregulation, inhibits E proliferation and delays differentiation, whereas PLZF knockdown induces opposite effects, independently of miRs-221 and -222 expression. The inverse correlation between PLZF and c-kit expression was found in normal CD34(+)38(+/-) hematopoietic progenitor/stem cells and in acute myeloid leukemias of M0/M1 French-American-British subtypes, suggesting that the control of PLZF on c-kit expression may be crucial at the level of the stem cell/progenitor compartment. Altogether, our data indicate a new mechanism of regulation of c-kit expression that involves a transcriptional control by PLZF in CD34(+) cells and early erythropoiesis.

Adiponectin: an intriguing hormone for paediatricians

Adiponectin, a protein hormone produced by adipocytes, is also found in breast milk, which in turn is implicated in childhood obesity prevention. Although a biological role for adiponectin has not been firmly established, clinical and experimental research indicates that it regulates lipid and glucose metabolism, affects foetal development, and exerts anti-inflammatory and antiatherogenic effects.

CONCLUSION

This review demonstrates an emerging interest of paediatric research on adiponectin. A better understanding of adiponectin's bioactivity might clarify whether breast milk indeed prevents childhood obesity.

Circulating haemopoietic and endothelial progenitor cells are decreased in COPD

Circulating CD34+ cells are haemopoietic progenitors that may play a role in tissue repair. No data are available on circulating progenitors in chronic obstructive pulmonary disease (COPD). Circulating CD34+ cells were studied in 18 patients with moderate-to-severe COPD (age: mean+/-sd 68+/-8 yrs; forced expiratory volume in one second: 48+/-12% predicted) and 12 controls, at rest and after endurance exercise. Plasma concentrations of haematopoietic growth factors (FMS-like tyrosine kinase 3 (Flt3) ligand, kit ligand), markers of hypoxia (vascular endothelial growth factor (VEGF)) and stimulators of angiogenesis (VEGF, hepatocyte growth factor (HGF)) and markers of systemic inflammation (tumour necrosis factor (TNF)-alpha, interleukin (IL)-6, IL-8) were measured. Compared with the controls, the COPD patients showed a three-fold reduction in CD34+ cell counts (3.3+/-2.5 versus 10.3+/-4.2 cells.microL-1), and a 50% decrease in AC133+ cells. In the COPD patients, progenitor-derived haemopoietic and endothelial cell colonies were reduced by 30-50%. However, four COPD patients showed progenitor counts in the normal range associated with lower TNF-alpha levels. In the entire sample, CD34+ cell counts correlated with exercise capacity and severity of airflow obstruction. After endurance exercise, progenitor counts were unchanged, while plasma Flt3 ligand and VEGF only increased in the COPD patients. Plasma HGF levels were higher in the COPD patients compared with the controls and correlated inversely with the number of progenitor-derived colonies. In conclusion, circulating CD34+ cells and endothelial progenitors were decreased in chronic obstructive pulmonary disease patients and could be correlated with disease severity.

Impaired myelopoiesis in mice devoid of interferon regulatory factor 1

Interferon regulatory factor (IRF)-1 is a transcription factor controlling the expression of several genes, which are differentially induced depending on the cell type and signal. IRF-1 modulates multiple functions, including regulation of immune responses and host defence, cell growth, cytokine signalling and hematopoietic development. Here, we investigated the role of IRF-1 in granulocytic differentiation in mice with a null mutation in the IRF-1 gene. We show that IRF-1(-/-) bone marrow cells exhibit an increased number of immature granulocytic precursors, associated with a decreased number of mature granulocytic elements as compared to normal mice, suggestive of a defective maturation process. Clonogenetic analyses revealed a reduced number of CFU-G, CFU-M and CFU-GM colonies in IRF-1(-/-) mice, while the number of BFU-E/CFU-E colonies was unchanged. At the molecular level, the expression of CAAT-enhancer-binding protein (C/EBP)-epsilon, -alpha and PU.1 was substantially lower in the CD11b(+) cells from the bone marrow of IRF-1(-/-) mice as compared to cells from wild-type mice. These results, together with the fact that IRF-1 is markedly induced early during granulo-monocytic differentiation of CD34+ cells, highlight the pivotal role of IRF-1 in the early phases of myelopoiesis.

Effect of ethanol on the oxidation of atrazine in the remediation of contaminated soil

The oxidation of an atrazine solution obtained from a flushing treatment of a contaminated soil was investigated. Experimental tests were performed on an artificially contaminated standard soil. Atrazine was removed from the soil by flushing with an aqueous solution at 5% volume of ethanol. Oxidative Fenton-type treatment on the extracted solution was then performed in order to transform atrazine into its by-products. The influence of different concentration of ethanol on atrazine oxidation was studied. Results show that the oxidative treatment is strongly affected by the ethanol residual amount. The degradation mechanism of atrazine during oxidation with Fenton's reagent in the presence of ethanol was also investigated.

Use of a standard system to evaluate the matrix effect on the treatment of a solution from atrazine contaminated soils

The influence of humic substances on the electrochemical treatment of solutions resulting from the remediation of atrazine contaminated soil has been investigated. In particular the effect on the hydrogen peroxide production stage and the effect on the hydroxyl radical oxidation treatment have been separately studied. In order to quickly assess the possible inhibition of the removal, an inorganic system has been adopted as a standard system. The results confirm the validity of electrochemical technologies also for the treatment of a real effluent where a matrix effect is expected since the organic matter content affects only the hydrogen peroxide production.

Treatment of the solution extracted from metal contaminated soils by reverse osmosis and chemical precipitation

In this study a process for the remediation of soils contaminated by lead or copper is proposed, consisting of the operations in sequence: soil flushing, membrane treatment, acidification, and metal precipitation. Pb(II) and Cu(II) extraction from a synthetically contaminated soil using a 0.05 M EDTA aqueous solution were investigated in column. The metal removal efficiencies and the final soil metal concentration were 98.2% and 37.96 mg/g respectively for lead and 95.4% and 59.20 mg/kg for copper. The extracted solutions were concentrated through a membrane treatment to reduce the water content up to the 75% and to obtain a permeate metal concentration in compliance with the Italian Environmental Regulation. The recovery of the used EDTA from the retentate solution, with recovery yield of at least 85.4%, was also obtained through acidification. Metal precipitation from the filtered solution was then performed according two different methods, achieving metal removal yield of more than 99.4%.

Oxidation of phosphorus compounds by Fenton's reagent

In the present work a Fenton's treatment for the oxidation of a phosphorous compounds mixture, simulating a match manufacturing industry wastewater, were studied. Experimental tests were performed on three sample solutions at a phosphorus concentration of 250, 500 and 750 mg/l. In each solution an equal amount of sodium phosphite and sodium hypophosphite was dissolved. The investigation of pH, temperature and reagents ratio on the oxidation rate led to the individuation of the optimal process operating conditions. The results show that Fenton's reagent provides a powerful conversion to phosphate of the phosphorous solution. In particular at pH=3.5 and 20 degrees C a residual concentration of non oxidized phosphorus in compliance with the Italian regulation limits for industrial wastewater disposal. Tests performed on sample solution of 500 mg/l P and 750 mg/l P by adding hydrogen peroxide and bivalent iron in three sequential steps led to similar reaction efficiencies to tests carried out adding both Fenton's reagents in one step, but with a remarkably lower reagents consumption.

Fenton-type treatment: state of the art

The different currently used Fenton-type treatments, either chemically or electrochemically generated, are reviewed. A particular attention is devoted to the traditional Fe++/H2O2 chemical process and to the indirect electrochemical oxidation which uses in situ generated hydrogen peroxide. Mechanisms and experimental conditions employed for the optimisation of each technology are reported; moreover advantages and main limitations are discussed.

Experimental study of the remediation of atrazine contaminated soils through soil extraction and subsequent peroxidation

This paper presents a feasibility study in the field of the remediation of soils contaminated with atrazine. Experimental tests were performed on an artificially contaminated synthetic soil. Atrazine was removed from the soil by flushing with an aqueous solution at 5 vol.% of ethanol. Experimental tests of evaporation and Fenton's oxidation on the extracted solution were then performed in order to transform atrazine into its oxidation products. Tests were performed in the presence of a peroxide excess the ratio between Fe(2+) and H(2)O(2) was 1:10. Peroxide was first added in order to reduce the consumption of hydroxyl radicals by their reaction with the excess of Fe(2+). The degradation mechanism of atrazine during oxidation with Fenton's reagent in the presence of ethanol was investigated. Results showed that due to the non selective nature of Fenton's reagent a high consumption of reagent was needed to achieve a significant atrazine oxidation from solutions at 4.5 vol.% of ethanol. While at a Fe(2+) concentration of 3mM atrazine practically disappeared from pure aqueous solutions within 2h, a degradation yield of only 28.1% was observed in the presence of ethanol even when Fe(2+) concentration was 15 mM.

A steady-state model for the evaluation of disk rotational speed influence on RBC kinetic: model presentation

The physical and biological mechanisms of attached-biomass growth were analyzed and a steady-state model was proposed to determine the soluble carbonaceous removal in an RBC unit for different organic loading rates in the reactor. The objective of the model was the prediction of the organic loading rate corresponding to the maximum removal capacity in the system. A system of equations was solved where the influent soluble carbonaceous substrate concentration was the main variable. Monod's rate law was used for the growth of microorganism: the soluble carbonaceous substrate was the limiting substrate. Endogenous decay was neglected. The influence of disk rotational speed on the RBC removal capacity was investigated, the disk rotational speed being a parameter acting on oxygen transfer in the biofilm. The criteria for the evaluation of the kinetic parameter in the model were proposed.

Levels and risk assessment for humans and ecosystems of platinum-group elements in the airborne particles and road dust of some European cities

Traffic is the main source of platinum-group element (PGE) contamination in populated urban areas. There is increasing concern about the hazardous effects of these new pollutants for people and for other living organisms in these areas. Airborne and road dusts, as well as tree bark and grass samples were collected at locations in the European cities of Göteborg (Sweden), Madrid (Spain), Rome (Italy), Munich (Germany), Sheffield and London (UK). Today, in spite of the large number of parameters that can influence the airborne PGE content, the results obtained so far indicate significantly higher PGE levels at traffic sites compared with the rural or non-polluted zones that have been investigated (background levels). The average Pt content in airborne particles found in downtown Madrid, Göteborg and Rome is in the range 7.3-13.1 pg m(-3). The ring roads of these cities have values in the range 4.1-17.7 pg m(-3). In Munich, a lower Pt content was found in airborne particles (4.1 pg m(-3)). The same tendency has been noted for downtown Rh, with contents in the range 2.2-2.8 pg m(-3), and in the range 0.8-3.0 and 0.3 pg m(-3) for motorway margins in Munich. The combined results obtained using a wide-range airborne classifier (WRAC) collector and a PM-10 or virtual impactor show that Pt is associated with particles for a wide range of diameters. The smaller the particle size, the lower the Pt concentration. However, in particles <PM-10, some of the highest values correspond to the fraction <0.39 microm. Considering an average Pt content in all particles of approximately 15 pg m(-3), which is representative for all countries and environmental conditions, the tracheobronchial fraction represents approximately 10% and the alveolar fraction approximately 8% of the total particles suspended in air. However, from the environmental risk point of view, an exposure to PGEs in traffic-related ambient air is at least three orders of magnitude below the levels for which adverse health effects might theoretically occur (of approx. 100 ng m(-3)). Therefore, today inhalation exposure to PGEs from automotive catalysts does not seem to pose a direct health risk to the general population. Even though the data available today indicate no obvious health effects, there are still a number of aspects related to PGEs and catalysts that justify further research. First, continual monitoring of changes in PGE levels in air and road dust is warranted, to make sure that there is no dramatic increase from today's levels. Secondly, more detailed information on the chemical composition of the PGE-containing substances or complexes leaving the catalyst surface and the size distribution of the PGE-containing particles released during driving will facilitate a more in-depth human risk assessment.

Experimental assessment of electrochemical processes in the remediation of atrazine contaminated soils

The electrochemical oxidation of an atrazine solution obtained from a flushing treatment of a contaminated soil was investigated. The influence of ethanol on atrazine oxidation was studied. Results show that the electrogenerated Fenton's reagent provides a complete degradation of atrazine and its main chlorinated by-products via N-dehalkylation and dechlorination. This process therefore presents an effective alternative to the chemical oxidation treatment which necessarily needs a further biological state.

Treatment of industrial landfill leachate by means of evaporation and reverse osmosis

In this paper a process for the treatment of landfill leachate involving evaporation and reverse osmosis was proposed. Experimental tests were performed on an industrial landfill leachate. The leachate was subjected to evaporation so as to obtain a distillate containing a small amount of organic material and a substantial amount of inorganic substances (consisting primarily of metals and ammonium salts). The distillate of the evaporation treatment was then subjected to reverse osmosis. The reverie osmosis tests were performed using two different membranes: the AD membrane (thin two-ply film of polyamide) and the SC membrane (thin three-ply film of polyamide). Tests carried out at different values of pH showed a reduction of organic content of about 88% when AD membranes were used and about 80% with SC membranes independently of pH. As regards ammonium, comparable reductions of over 97% were registered for both types of membrane in the optimal conditions of pH = 6.4 (97.1% for AD membranes and 97.7% for SC).

Innovative methods for removing phosphorus from wastewaters

Wastewater containing a mixture of hypophosphites and phosphites was treated in order to assess the possibility of attaining high levels of phosphorus oxidation to phosphate. An initial series of tests based on chemical oxidation by means of Fenton's reagent demonstrated the feasibility of this process for solutions containing 250-750 mg/l of phosphorus. Removal yields of up to 98% were attained at pH 3.5 by using variable ratios of [H2O2]/[Fe2+]. The second series involved the electrolytic generation of Fenton's reagent at pH 2-2.5 through cathodic oxygen reduction. This demonstrated the possibility of obtaining quantitative yields for solutions containing 80-160 mg/l P with a constant [H2O2]/[Fe2+] ratio of 3.94. Economic comparison of the two processes showed that the operative cost of the electrochemical treatment is comparable to that of the chemical process.

Assessment of heart rate variability changes during dipyridamole infusion and dipyridamole-induced myocardial ischemia: a time variant spectral approach

OBJECTIVES

We sought to evaluate changes in RR interval variability during dipyridamole infusion and dipyridamole-induced myocardial ischemia.

BACKGROUND

Myocardial ischemia and the autonomic nervous system can be mutually interdependent. Spectral analysis of RR interval variability is a useful tool in assessing autonomic tone.

METHODS

We used a time variant autoregressive spectral estimation algorithm that could extract spectral variables even in the presence of nonstationary signals. Two groups were considered: group A (patients with ischemia, n = 15) with effort or mixed angina, angiographically assessed coronary artery disease and positive exercise and dipyridamole echocardiographic test results, and group B (control subjects, n = 10) with normal exercise and dipyridamole echocardiographic test results. We investigated the following variables: RR interval mean and variance, low frequency (LF) and high frequency (HF) power in normalized units, LF ratio (LF/LFbasal power), HF ratio (HF/HFbasal power) and LF/HF ratio. For each test epoch, we calculated for group A and group B the mean value +/- SE of all indexes considered. Differences due to an effect either of group (ischemic vs. control) or of time (including both drug and ischemia effects) were analyzed by using analysis of variance for repeated measurements.

RESULTS

Dipyridamole injection was characterized by a reduction of all spectral components in negative test. The LF ratio was the only variable able to discriminate patients with ischemia from control subjects (p < 0.05), whereas a time effect was evident for both mean RR interval and high frequency power in normalized units (p < 0.05). The LF ratio decreased in group B from 1 +/- 0.00 (basal) to 0.31 +/- 0.22 (peak), and increased in group A from 1 +/- 0.00 to 15.41 +/- 6.59, respectively. Results of an unpaired t test comparing the peak values of the two groups were also statistically significant (p < 0.01).

CONCLUSIONS

Our data show that time variant analysis of heart rate variability evidences an increase in the low frequency ratio that allows differentiation of positive from negative test results, suggesting that the electrocardiogram may contain ischemia information unrelated to ST-T variations, even if their enhancement requires a more complex data processing procedure.

Clinical evaluation of algorithms for ST measurement during exercise test

HYPOTHESIS

Computer processing of the exercise electrocardiogram (ECG) has many advantages, but the reliability of the analysis algorithms is not easily evaluable. No standard annotated database, nor recommended practice for testing and reporting performance results is available: thus, performance evaluation of such devices can be accomplished only by using a set of unannotated recordings, obtained in clinical practice. We evaluated the accuracy of an original microcomputer-based exercise test analyzer comparing the ST computer output with the measurements obtained by two experienced cardiologists.

METHODS

Six hundred ECG strips were randomly selected from the exercise test recordings of 60 patients. The ST shift (at J + 80 ms) was blindly assessed by two observers (with the aid of a calibrated lens) and compared with computer measurements. Correlation coefficients, linear regression equations, percent of discrepant measurements, and 95% confidence limits of the mean error were calculated for all leads, peripheral leads, precordial leads, and "stress-test" leads (II, III, aVF, V4, V5, V6).

RESULTS

The computer did not analyze five samples on a total of 600 (0.83%) ECG strips because of excessive noise or signal loss, while 51 (8.5%) were considered unreadable by both observers and 67 (11.2%) were rejected by at least one observer. Correlation between the measurements taken by computer and observer(s) measurements was statistically significant (p < 0.001 for all lead groups), no systematic measurement bias was found, and the mean difference was lower than human eye resolution.

CONCLUSIONS

Our algorithms provide results as good as those provided by trained cardiologists in measuring ST changes occurring during exercise test. However, this study did not evaluate whether computer improvement of the signal-to-noise ratio would allow accurate measurements even on cardiologists' uninterpretable ECG. This potential advantage of computer-assisted analysis could be assessed only by using a dedicated exercise test database, in which different patterns of noise are superimposed on noise-free recordings previously annotated for ST level.

Time-variant power spectrum analysis for the detection of transient episodes in HRV signal

A time-variant algorithm of autoregressive (AR) identification is introduced and applied to the heart rate variability (HRV) signal. The power spectrum is calculated from the AR coefficients derived from each single RR interval considered. Time-variant AR coefficients are determined through adaptive parametric identification with a forgetting factor which obtains weighed values on a running temporal window of 50 preceding measurements. Power spectrum density (PSD) is hence obtained at each cardiac cycle, making it possible to follow the dynamics of the spectral parameters on a beat-by-beat basis. These parameters are mainly the LF (low frequency) and the HF (high frequency) powers, and their ratio LF/HF. These together account for the balanced sympatho-vagal control mechanism affecting the heart rate. This method is applied to subjects suffering from transient ischemic attacks. The time variant spectral parameters suggest an early activation of LF component in the HRV power spectrum. It precedes by approximately 1.5-2 min the tachycardia and the ST displacement, generally indicative of the onset of an ischemic episode. The results suggest an arousal of sympathetic system before the acute attack.

Double-blind comparison of perindopril and captopril in hypertension. Effects on left ventricular morphology and function

Using digitized M-mode echocardiograms, we compared, in a double-blind study, the effects of 4 to 8 mg perindopril given once daily and 25 to 50 mg captopril given twice daily on the left ventricle (LV) in 20 hypertensive patients. Both treatments significantly (P less than .001) lowered blood pressure, reducing systemic vascular resistances. After 3 months both drugs induced a comparable percentage of reduction in LV mass, with an increase in the peak rate of LV relaxation and no changes in the peak rate of LV contraction. Our results demonstrate that perindopril once daily is an effective antihypertensive agent; it is also able, like captopril, to induce regression of LV hypertrophy, with improvement in diastolic performance and no deterioration in ventricular systolic function.

[Description of a system for automatic analysis of ambulatory electrocardiography using a microcomputer]

An automatic ambulatory electrocardiogram analyzer was developed using a self-powered fast reader of FM recorded cassettes and a "general purpose" microcomputer with 640 Kbytes of RAM and 20 Mbytes of mass memory on hard-disk. Original algorithms were developed for analog to digital conversion, data storage on hard-disk, QRS detection and classification and rhythm analysis. Reliability of the system was evaluated, when appropriate, using standard databases. The relevant features of our analyzer include a favourable cost/benefit ratio, powerful interactive facilities and the typical flexibility of the non dedicated hardware.