Source and nature of inhaled atmospheric dust from trace element analyses of human bronchial fluids

Rapid volcanic eruptions quickly ejecting large amounts of dust provoke the accumulation of heavy metals in people living in surrounding areas. Analyses of bronchoalveolar lavage samples (BAL) collected from people exposed to the paroxysmal 2001 Etna eruption revealed a strong enrichment of many toxic heavy metals. Comparing the BAL to the dust composition of southeastern Sicily, we found that only V, Cr, Mn, Fe, Co, and U enrichment could be related to the volcanic event, whereas Ni, Cu, Cd, and Pb contents come from the dissolution of particles of anthropogenic origin. Furthermore, the nature of these inhaled anthropogenic particles was revealed by anomalous La and partially Ce concentrations in BAL that were consistent with a mixture of road dust and petroleum refinery emissions. Our results indicate that trace element distribution in BAL is a suitable tracer of human exposure to different sources of inhaled atmospheric particulates, allowing investigations into the origin of source materials inhaled by people subjected to atmospheric fallout.     

Polymer electrolyte membrane water electrolysis: status of technologies and potential applications in combination with renewable power sources

Technological improvements in polymer electrolyte membrane water electrolysers (PEMWEs) are promoted by their exciting possibilities to operate with renewable power sources. In this paper, a synopsis of the research efforts concerning with the development of electrocatalysts, polymer electrolytes and stack hardware components is presented. The most challenging problem for the development of PEMWEs is the enhancement of oxygen evolution reaction rate. At present, there are no practical alternatives to noble metal-based oxide catalysts such as IrO₂ and RuO₂. As well as carbon supported Pt nanoparticles are the benchmark cathode catalysts for hydrogen evolution. High noble metal loading on the electrodes and the use of perfluorosulfonic membranes significantly contribute to the cost of these devices. Critical areas include the design of appropriate mixed electrocatalysts and their dispersion on low cost Ti-oxide like supports to increase catalyst utilization. Moreover, the development of alternative membranes with enhanced mechanical properties for high pressure applications, proper conductivity and reduced gas cross-over is strongly required. This latter aspect is also addressed by the development of proper recombination catalysts. The development of anodic mixed non-noble transition metal oxides with spinel or perovskite structure and proper resistance to chemical degradation in the acidic environment and electrochemical corrosion is also an active area of research. Similarly, efforts are also being addressed to Pd and Ru based cathode formulations with cheaper characteristics than Pt. Whereas, concerning with stack hardware, cost reduction may be addressed by replacing Ti-based diffusion media and bipolar plates with appropriate and cost-effective stainless steel materials with enhanced resilience to chemical and electrochemical corrosion. Regarding the combination with renewable power sources, PEM electrolysers can find suitable applications for peak shaving in integrated systems grid connected or in grid independent operating conditions where hydrogen generated through electrolysis is stored and then via fuel cell converted back to electricity when needed or used to refill fuel cell-based cars. Hydrogen is the most promising clean energy carrier to accomplish the sustainable production of energy and a synergy among hydrogen, electricity and renewable energy sources is highly desired.     

Integrating Distributed Data Bases into the Information Architecture

Abstract

To keep pace with rapid changes in corporate business requirements, organizations have begun to integrate distributed data base technology into their information architectures. Distributed data base management systems (DDBMSs) in particular promote the departmental sharing of data as well as easy access to data in a distributed environment, both key aspects of any data management strategy. This article describes the elements of distributed data base technology to help IS managers control the integration of distributed data bases in their organizations.     

Time–frequency analysis of tribological systems—part I: implementation and interpretation

A novel technique adapting the time–frequency analysis has been utilized to characterize stationary and non-stationary signals from tribological interactions. This representation displays time, frequency, and signal magnitude to decipher signals emanating from such interactions. Short-time Fourier transform, Wigner, Coi–Williams, and Zhao–Atlas–Marks distributions are suited to represent stationary and non-stationary signals. Some of the most complex tribological phenomena involve head–disk interactions in magnetic recording systems. Examples drawn from practical head–disk interface tests are analyzed by using the fast Fourier transform algorithm to illustrate the dynamic features of various distributions. Time–frequency representation of output spectrums of laser doppler vibrometer (LDV), strain gage sensor, and acoustic emission (AE) sensor obtained from head–disk experiments giving evidence of stationary and non-stationary behavior are investigated.     

Impact of DNA-surface interactions on the stability of DNA hybrids

The structure and stability of single- and double-stranded DNA hybrids immobilized on gold are strongly affected by nucleotide-surface interactions. To systematically analyze the effects of these interactions, a set of model DNA hybrids was prepared in conformations that ranged from end-tethered double-stranded to directly adsorbed single-stranded (hairpins) and characterized by surface plasmon resonance (SPR) imaging, X-ray photoelectron spectroscopy (XPS), fluorescence microscopy, and near edge X-ray absorption fine structure (NEXAFS) spectroscopy. The stabilities of these hybrids were evaluated by exposure to a series of stringency rinses in solutions of successively lower ionic strength and by competitive hybridization experiments. In all cases, directly adsorbed DNA hybrids are found to be significantly less stable than either free or end-tethered hybrids. The surface-induced weakening and the associated asymmetry in hybridization responses of the two strands forming hairpin stems are most pronounced for single-stranded hairpins containing blocks of m adenine (A) nucleotides and n thymine (T) nucleotides, which have high and low affinity for gold surfaces, respectively. The results allow a qualitative scale of relative stabilities to be developed for DNA hybrids on surfaces. Additionally, the results suggest a route for selectively weakening portions of immobilized DNA hybrids and for introducing asymmetric hybridization responses by using sequence design to control nucleotide-surface interactions--a strategy that may be used in advanced biosensors and in switches or other active elements in DNA-based nanotechnology.     

Yttrium and lanthanides in human lung fluids, probing the exposure to atmospheric fallout

Inhalation of airborne particles can produce crystallization of phosphatic microcrysts in intraaveolar areas of lungs, sometimes degenerating into pulmonary fibrosis. Results of this study indicate that these pathologies are induced by interactions between lung fluids and inhaled atmospheric dust in people exposed to volcanic dust ejected from Mount Etna in 2001. Here, the lung solid-liquid interaction is evaluated by the distribution of yttrium and lanthanides (YLn) in fluid bronchoalveolar lavages on selected individuals according the classical geochemical approaches. We found that shale-normalised patterns of yttrium and lanthanides have a 'V shaped' feature corresponding to the depletion of elements from Nd to Tb when compared to the variable enrichments of heavy lanthanides, Y, La and Ce. These features and concurrent thermodynamic simulations suggest that phosphate precipitation can occur in lungs due to interactions between volcanic particles and fluids. We propose that patterns of yttrium and lanthanides can represent a viable explanation of some pathology observed in patients after prolonged exposure to atmospheric fallout and are suitable to become a diagnostic parameter of chemical environmental stresses.     

Attributable risk for symptomatic liver cirrhosis in Italy. Collaborative Groups for the Study of Liver Diseases in Italy

BACKGROUNDS/AIMS: Knowledge of the proportion of liver cirrhosis attributable to the main risk factors is largely based on methodologically questionable clinical reports. METHODS: The proportion of newly diagnosed cases of symptomatic liver cirrhosis attributable to known risk factors was estimated by a case-control study performed during 1989-1996 in 23 medical divisions of several hospitals distributed throughout Italy. Cases were 462 inpatients with cirrhosis admitted for the first time for liver decompensation. Controls were 651 patients admitted during the same period and to the same hospitals as the cases, for acute diseases unrelated to alcohol and virus infection. The proportion of symptomatic liver cirrhosis cases due to alcohol intake and hepatitis B and C viruses and the combination of these was expressed as the population attributable risk. RESULTS: Attributable risks were 67.9% (95% confidence interval (CI): 53.8-79.4) for alcohol, 40.1% (95% CI: 35.3-45.2) for hepatitis C virus and 4.4% (95% CI: 2.5-7.6) for hepatitis B virus. The three factors together explained 98.1% (95% CI: 81.6-99.6) of cases in men and 67.0% (95% CI: 50.4-85.8) in women. CONCLUSIONS: Alcohol is the risk factor with the highest impact on symptomatic liver cirrhosis risk in Italy. From a public health viewpoint, with the elimination of the well-known risk factors (particularly alcohol and hepatitis C virus), liver cirrhosis should become a rare disease.     

Degradation of oxygen-depolarized Ag-based gas diffusion electrodes for chlor-alkali cells

Oxygen-depolarized cathodes consisting of gas-diffusion electrodes (GDEs) for electrolysis in a chlor-alkali cell at 90 °C were studied. The electrode design was based on a carbon-free catalyst and comprised of a mixture of micronized silver particles, a small amount of Hg and PTFE binder. The cathodes were investigated by electrochemical measurements, and surface and morphological analyses before and after different operation times in chlor-alkali cells. Electrode stability was investigated by life-time tests. The surface properties of gas diffusion electrodes were studied for both fresh and used cathodes by X-ray photoelectron spectroscopy (XPS). Transmission (TEM) and scanning electron microscopy (SEM-EDX) were used to investigate morphology. The bulk of gas diffusion electrodes was studied by X-ray diffraction (XRD) and thermogravimetric analysis (TG-DSC). At least two main degradation processes that occur on different time-scales were identified and attributed to segregation and loss of the second metal at the interface and a decrease in the hydrophilic properties with time. Furthermore, an increase in the precipitation of compounds from the reaction process also decreased performance by the occlusion of reaction pores.     

Familial hemophagocytic lymphohistiocytosis. Primary hemophagocytic lymphohistiocytosis

Hemophagocytic lymphohistiocytosis represents a spectrum of pathogenetically different diseases including the rapidly fatal autosomal recessive disease of familial hemophagocytic lymphohistiocytosis (FHL). The onset is usually during the first years of life with fever, cytopenia, and hepatosplenomegaly. Neurologic symptoms may supervene. Similar symptoms may occur in the infection-(virus-)associated or malignancy-associated hemophagocytic syndromes (IAHS/MAHS). Triggering infections can be found in all these diseases and do not allow for reliable differentiation. An international treatment protocol (HLH-94) has been developed for FHL, but immunomodulatory treatment may be justified in IAHS and MAHS as well, since they also have a high fatality rate.