The Kinetics of Adsorption and Desorption of Selected Semivolatile Hydrocarbons and HO Vapor on Two Mineral Dust Materials: A Molecular View.

A flowing gas experiment using a Knudsen flow reactor was performed on a series of seven semivolatile probe gases interacting with two often used mineral dust materials, namely, coarse Arizona test dust (ATD-C) and kaolinite. The semivolatile probe gases used were applinate (acetate ester), pipol (ethyl ester of 2-methylvaleric acid), benzylacetate (acetate ester of benzylalcohol), menthol (alcohol), toluene, limonene, and γ-terpinene (terpene hydrocarbon). Uptake experiments under molecular flow conditions resulted in absolute coverages and initial uptake coefficients γ based on the geometric sample surface.

Metastable Nitric Acid Trihydrate in Ice Clouds.

The composition of high-altitude ice clouds is still a matter of intense discussion. The constituents in question are ice and nitric acid hydrates, but the exact phase composition of clouds and its formation mechanisms are still unknown. In this work, conclusive evidence for a long-predicted phase, alpha-nitric acid trihydrate (alpha-NAT), is presented.

Quantitative Aspects of the Interfacial Catalytic Oxidation of Dithiothreitol by Dissolved Oxygen in the Presence of Carbon Nanoparticles.

The catalytic nature of particulate matter is often advocated to explain its ability to generate reactive oxygen species, but quantitative data are lacking. We have performed molecular characterization of three different carbonaceous nanoparticles (NP) by 1. identifying and quantifying their surface functional groups based on probe gas-particle titration; 2.

Transient mid-IR study of electron dynamics in TiO2 conduction band.

The dynamics of TiO2 conduction band electrons were followed with a novel broadband synchrotron-based transient mid-IR spectroscopy setup. The lifetime of conduction band electrons was found to be dependent on the injection method used. Direct band gap excitation results in a lifetime of 2.

δ15N measurement of organic and inorganic substances by EA-IRMS: a speciation-dependent procedure.

Little attention has been paid so far to the influence of the chemical nature of the substance when measuring δ(15)N by elemental analysis (EA)-isotope ratio mass spectrometry (IRMS). Although the bulk nitrogen isotope analysis of organic material is not to be questioned, literature from different disciplines using IRMS provides hints that the quantitative conversion of nitrate into nitrogen presents difficulties. We observed abnormal series of δ(15)N values of laboratory standards and nitrates.

Biomarkers of oxidative stress and its association with the urinary reducing capacity in bus maintenance workers.

Background: Exposure to particles (PM) induces adverse health effects (cancer, cardiovascular and pulmonary diseases). A key-role in these adverse effects seems to be played by oxidative stress, which is an excess of reactive oxygen species relative to the amount of reducing species (including antioxidants), the first line of defense against reactive oxygen species. The aim of this study was to document the oxidative stress caused by exposure to respirable particles in vivo, and to test whether exposed workers presented changes in their urinary levels for reducing species.

Coating carbon nanotubes with a polystyrene-based polymer protects against pulmonary toxicity.

Background: carbon nanotubes (CNT) can have adverse effects on health. Therefore, minimizing the risk associated with CNT exposure is of crucial importance. The aim of this work was to evaluate if coating multi-walled CNT (MWCNT) with polymers could modify their toxicity, thus representing a useful strategy to decrease adverse health effects of CNT.

Probing functional groups at the gas-aerosol interface using heterogeneous titration reactions: a tool for predicting aerosol health effects?

The complex chemical and physical nature of combustion and secondary organic aerosols (SOAs) in general precludes the complete characterization of both bulk and interfacial components. The bulk composition reveals the history of the growth process and therefore the source region, whereas the interface controls--to a large extent--the interaction with gases, biological membranes, and solid supports. We summarize the development of a soft interrogation technique, using heterogeneous chemistry, for the interfacial functional groups of selected probe gases [N(CH(3))(3), NH(2)OH, CF(3)COOH, HCl, O(3), NO(2)] of different reactivity.

Appendicular skeletal muscle mass is the strongest independent factor associated with femoral neck bone mineral density in adult and older men.

The relationship between bone mass and muscle mass may be due to the site-specific effects of loading on bone in adults and to lifestyle, nutritional, and hormonal factors. Another hypothesis is that the maintenance with aging of both appendicular muscle and bone mass may be determined by factors independent of all these previous factors, including genetic factors. In 160 healthy men aged 20 to 72years, we recorded femoral neck bone mineral density (FN BMD), relative appendicular skeletal muscle mass [RASM; appendicular skeletal muscle mass (kg)/height (cm)], age, body mass, maximum grip and knee extension strength, lifetime physical activities, calcium intake, tobacco smoking, and serum parathyroid hormone (PTH), estradiol (E2), free testosterone, dehydroepiandrosterone sulphate (DHEAS), insulin-like growth factor (IGF-I), sex hormone-binding globulin (SHBG), calcium, 25(OH) vitamin D, albumin, and creatinine clearance.

Determination of serum ferritin using immunoturbidimetry or chemiluminescent detection in comparison with radioimmunoassay a compendium of a methodological juxtaposition.

Background: The implementation of a ferritin assay other that by the RIA technique may be necessary in several laboratories. Indeed the RIA method presents limitations for routine determination: use of radioactive isotopes, high cost of reagents and low capacity (manual technique). This method was not suitable for all laboratories.

Low sit-to-stand performance is associated with low femoral neck bone mineral density in healthy women.

Bone mass may be adjusted to control the strains produced by muscular activity. We assessed the relationship between maximum rising strength (MRS), a new measurement of sit-to-stand performance, and femoral neck (FN) bone mineral density (BMD), taking into account possible confounding variables. The study population consisted of 249 healthy women aged 18-76.

Adverse effects of industrial multiwalled carbon nanotubes on human pulmonary cells.

The aim of this study was to evaluate adverse effects of multiwalled carbon nanotubes (MWCNT), produced for industrial purposes, on the human epithelial cell line A549. MWCNT were dispersed in dipalmitoyl lecithin (DPL), a component of pulmonary surfactant, and the effects of dispersion in DPL were compared to those in two other media: ethanol (EtOH) and phosphate-buffered saline (PBS). Effects of MWCNT were also compared to those of two asbestos fibers (chrysotile and crocidolite) and carbon black (CB) nanoparticles, not only in A549 cells but also in mesothelial cells (MeT5A human cell line), used as an asbestos-sensitive cell type.

Effect of antioxidants and exercise on bone metabolism.

We examined the effects of antioxidant supplementation in association with progressive aerobic training on the bone metabolism of healthy elderly individuals. For 8 weeks, 13 participants (mean age 74 years) received vitamin C (500 mg) and vitamin E (100 mg) daily and participated in a supervised progressive aerobic training programme. After the 8 weeks, 25-hydroxyvitamin D and 1,25-dihydroxyvitamin D concentrations were increased significantly by 42.

No negative impact of reduced leptin secretion on bone metabolism in male decathletes.

This study investigated the effect of intense physical activities that generate high mechanical constraints on bone metabolism and serum leptin concentrations and the potential relationships among bone mineral density (BMD), bone biochemical markers and leptin variation. Thirteen male decathletes (mean age 22.4 +/- 2.

Diagnosis of diffuse and localized arrhythmogenic right ventricular dysplasia by gated blood-pool SPECT.

Unlabelled: This study aimed to assess the ability of global and local systolic parameters measured with gated blood-pool SPECT (GBPS) to diagnose and characterize the severity of diffuse or localized arrhythmogenic right ventricular dysplasia (ARVD).

Methods: Fifty-nine subjects with symptomatic ventricular arrhythmias were prospectively included in the study. With the International Society and Federation of Cardiology criteria for ARVD as a gold standard, these subjects were classified as subjects without ARVD (21 control subjects) and patients with localized ARVD (16 patients) or diffuse ARVD (22 patients).

Heterogeneous chemistry of the NO3 free radical and N2O5 on decane flame soot at ambient temperature: reaction products and kinetics.

The interaction of NO3 free radical and N2O5 with laboratory flame soot was investigated in a Knudsen flow reactor at T = 298 K equipped with beam-sampling mass spectrometry and in situ REMPI detection of NO2 and NO. Decane (C10H22) has been used as a fuel in a co-flow device for the generation of gray and black soot from a rich and a lean diffusion flame, respectively. The gas-phase reaction products of NO3 reacting with gray soot were NO, N2O5, HONO, and HNO3 with HONO being absent on black soot.

The heterogeneous kinetics of HOBr and HOCl on acidified sea salt and model aerosol at 40-90% relative humidity and ambient temperature.

The HOBr and HOCl uptake coefficient gamma on H(2)SO(4)-acidified submicron salt aerosol of known size distribution was measured in an atmospheric pressure laminar flow reactor. The interaction time of the trace gas with the aerosol was in the range 15 to 90 s and led to gamma values in the range 10(-4) to 10(-2). The acidity of the aerosol is essential in order to enable heterogeneous reactions of HOBr on NaCl, recrystallized sea salt (RSS) and natural sea salt (NSS) aerosols.

Influence of monolayer amounts of HNO3 on the evaporation rate of H2O over ice in the range 179 to 208 K: a quartz crystal microbalance study.

The evaporation flux J(ev) of H2O from thin H2O ice films containing between 0.5 and 7 monolayers of HNO3 has been measured in the range 179 to 208 K under both molecular and stirred flow conditions in isothermal experiments. FTIR absorption of the HNO3/H2O condensate revealed the formation of metastable alpha-NAT (HNO(3).

Accuracy and precision of perfusion lung scintigraphy versus 133Xe-radiospirometry for preoperative pulmonary functional assessment of patients with lung cancer.

Purpose: This study sought to determine whether (133)Xe-radiospirometry (XRS) successfully selects patients able to undergo lung resection without postoperative respiratory complications and whether perfusion lung scintigraphy (PLS) is likely to provide a similar selection of patients for certain tumour stages.

Methods: Two hundred and eighty-four patients with resectable lung cancer underwent preoperative assessment of postoperative forced expiratory volume in 1 s (FEV(1)) by XRS and PLS. Correlations, Bland and Altman analysis and contingency tables were used to analyse the difference between the two predictive techniques.

The kinetics of H2O vapor condensation and evaporation on different types of ice in the range 130-210 K.

The kinetics of condensation (kc) and the evaporation flux (J(ev)) of H2O on ice were studied in the range 130-210 K using pulsed-valve and steady-state techniques in a low-pressure flow reactor. The uptake coefficient gamma was measured for different types of ice, namely, condensed (C), bulk (B), single crystal (SC), snow (S), and cubic ice (K). The negative temperature dependence of gamma for C, B, SC, and S ice reveals a precursor-mediated adsorption/desorption process in agreement with the proposal of Davy and Somorjai.

Correlation of preoperative thallium SPECT with histological grading and overall survival in adult gliomas.

Background: The management and prognosis of a glioma depend on the tumour's histological grade. Thus, preoperative prediction of the grade is routinely needed to indicate whether surgery or biopsies are required. It has been proposed that thallium single photon emission computed tomography (SPECT), in a relative short series, will aid this prediction.