Identification of the major HOx radical pathways in an indoor air environment.

OH and HO2 profiles measured in a real environment have been compared to the results of the INCA-Indoor model to improve our understanding of indoor chemistry. Significant levels of both radicals have been measured and their profiles display similar diurnal behavior, reaching peak concentrations during direct sunlight (up to 1.6×106 and 4.0×107  cm-3 for OH and HO2 , respectively). Concentrations of O3 , NOx , volatile organic compounds (VOCs), HONO, and photolysis frequencies were constrained to the observed values. The HOx profiles are well simulated in terms of variation for both species (Pearson's coefficients: pOH =0.55, pHO2 =0.76) and concentration for OH (mean normalized bias error: MNBEOH =-30%), HO2 concentration being always underestimated (MNBEHO2 =-62%). Production and loss pathways analysis confirmed HONO photolysis role as an OH precursor (here up to 50% of the production rate). HO2 formation is linked to OH-initiated VOC oxidation. A sensitivity analysis was conducted by varying HONO, VOCs, and NO concentrations. OH, HO2 , and formaldehyde concentrations increase with HONO concentrations; OH and formaldehyde concentrations are weakly dependent on NO, whereas HO2 concentrations are strongly reduced with increasing NO. Increasing VOC concentrations decreases OH by consumption and enhances HO2 and formaldehyde.

Assessment of indoor HONO formation mechanisms based on in situ measurements and modeling.

The photolysis of HONO has been found to be the oxidation driver through OH formation in the indoor air measurement campaign SURFin, an extensive campaign carried out in July 2012 in a classroom in Marseille. In this study, the INCA-Indoor model is used to evaluate different HONO formation mechanisms that have been used previously in indoor air quality models. In order to avoid biases in the results due to the uncertainty in rate constants, those parameters were adjusted to fit one representative day of the SURFin campaign. Then, the mechanisms have been tested with the optimized parameters against other experiments carried out during the SURFin campaign. Based on the observations and these findings, we propose a new mechanism incorporating sorption of NO2 onto surfaces with possible saturation of these surfaces. This mechanism is able to better reproduce the experimental profiles over a large range of conditions.

Speciation of non-methane hydrocarbons (NMHCs) from anthropogenic sources in Beirut, Lebanon.

The chemical composition of emissions from the different anthropogenic sources of non-methane hydrocarbons (NMHC) is essential for modeling and source apportionment studies. The speciated profiles of major NMHC sources in Lebanon, including road transport, gasoline vapor, power generation, and solvent use were established. Field sampling have been carried out by canisters in 2012. Around 67 NMHC (C2 to C9) were identified and quantified by using a gas chromatograph equipped with a flame ionization detector. Typical features of the roadway emissions included high percentages of isopentane, butane, toluene, xylenes, ethylene, and ethyne. Gasoline evaporation profiles included high percentage of the C4-C5 saturated hydrocarbons reaching 59 %. The main compounds of the power generator emissions are related to combustion. Toluene and C8-C9 aromatics were the most abundant species in emissions from paint applications. Finally, the impact of the use of region-specific source profile is tackled regarding the implication on air quality.

Implantable electrophysiologic cardiac device infections: a risk factor analysis.

The risk of cardiac device infection (CDI) is rising significantly, with several risk factors identified. The purpose of this study is to determine the rate of CDI at our center and to assess the associated risk factors, in order to define appropriate measures to prevent this complication. We retrospectively reviewed all cases of patients with CDI at St. George Hospital between February 1999 and July 2010. Each case was matched with three controls. We performed a descriptive and bivariate analysis to identify significant risk factors. Eighteen case patients and 54 control subjects met the inclusion criteria. An organism was recovered in 58 % of the cases. Significant risk factors included previous history of CDI (p < 0.001), recent manipulation (p < 0.001), trauma to the site of implant (p = 0.003), having a dual chamber/dual lead pacemaker (p = 0.002), and development of post-procedural hematoma (p = 0.012). Our findings complement the results of previous studies. We recommend a pre-procedural risk assessment and a thorough post-implantation follow-up to prevent the development of infective complications.

Novel antifungal agents as salvage therapy for invasive aspergillosis in patients with hematologic malignancies: posaconazole compared with high-dose lipid formulations of amphotericin B alone or in combination with caspofungin.

In patients with hematologic malignancy, invasive aspergillosis continues to be associated with high mortality even when treated with conventional antifungal therapy. To investigate novel antifungal agents, we compared 53 patients who received posaconazole salvage therapy to 52 contemporary control patients who received high-dose lipid formulation of amphotericin B (HD-LPD/AMB at > or = 7.5 mg kg(-1) per day) and 38 other control patients who received caspofungin plus HD-LPD/AMB. Patients in the three groups had similar. The overall response rate to salvage therapy was 40% for posaconazole, 8% for HD-LPD/AMB (P < or = 0.001) and 11% for combination therapy (P < 0.002). Aspergillosis contributed to the death of 40% of posaconazole group, 65% of the HD-LPD/AMB group and 68% of the combination group (P < or = 0.008). By multivariate analysis, posaconazole therapy independently improved response (9.5; 95% confidence interval, 2.8-32.5; P < 0.001). HD-LPD/AMB alone or in combination was associated with a significantly higher rate of nephrotoxicity (P < or = 0.02) and hepatotoxicity (P < 0.03). In conclusion, posaconazole salvage therapy demonstrated greater efficacy and safety than HD-LPD/AMB alone or in combination with caspofungin in the salvage therapy of invasive aspergillosis in hematologic malignancy.