Selective identification of cyclopentaring-fused PAHs and side-substituted PAHs in a low pressure premixed sooting flame by photoelectron photoion coincidence spectroscopy.

This work reports on the selective on-line identification of polycyclic aromatic hydrocarbons (PAHs) formed in a low-pressure methane sooting flame, carried out using the double imaging Photoelectron Photoion Coincidence Spectroscopy method (i2PEPICO) on the DESIRS VUV beamline at the synchrotron SOLEIL. Generally, this work demonstrates the capabilities of the i2PEPICO method to identify PAHs in sooting flames, and in particular to distinguish cyclopentaring-fused PAHs (CP-PAHs) and side-substituted PAHs from their benzenoid isomers. Experimental threshold photoelectron spectra of four CP-PAHs: acenapthylene (C12H8, 152 m/z), acenaphtene (C12H10, 154 m/z), fluoranthene (C16H10, 202 m/z) and benzo(ghi)fluoranthene (C18H10, 226 m/z) are also reported for the first time.

Impact of the spectral and spatial properties of natural light on indoor gas-phase chemistry: Experimental and modeling study.

The characteristics of indoor light (intensity, spectral, spatial distribution) originating from outdoors have been studied using experimental and modeling tools. They are influenced by many parameters such as building location, meteorological conditions, and the type of window. They have a direct impact on indoor air quality through a change in chemical processes by varying the photolysis rates of indoor pollutants. Transmittances of different windows have been measured and exhibit different wavelength cutoffs, thus influencing the potential of different species to be photolysed. The spectral distribution of light entering indoors through the windows was measured under different conditions and was found to be weakly dependent on the time of day for indirect cloudy, direct sunshine, partly cloudy conditions contrary to the light intensity, in agreement with calculations of the transmittance as a function of the zenithal angle and the calculated outdoor spectral distribution. The same conclusion can be drawn concerning the position within the room. The impact of these light characteristics on the indoor chemistry has been studied using the INCA-Indoor model by considering the variation in the photolysis rates of key indoor species. Depending on the conditions, photolysis processes can lead to a significant production of radicals and secondary species.

[Cholelithiasis in children with sickle cell disease: experience of a French pediatric hospital]. / Lithiase biliaire chez l'enfant drépanocytaire: expérience d'un hôpital pédiatrique parisien.

BACKGROUND: Gallstones are frequently encountered in sickle cell disease. Their complications are difficult to distinguish from vaso-occlusive abdominal pain and they can sometimes threaten the patient's life. The aim of this study was to describe our local experience with cholelithiasis in children with sickle cell disease. PATIENTS AND METHODS: We analyzed the follow-up records and abdominal sonography results of 185 children with sickle cell anemia, aged zero to 18 years, followed up in Trousseau Children's Hospital (Paris) from 1982 to 1998. RESULTS: Cholelithiasis was detected in 26 patients. The youngest patient was five years old. Cholelithiasis was discovered because of clinical manifestations in 12 patients. Asymptomatic cholelithiasis patients developed clinical manifestations in 28% cases in a maximum delay of two and a half years after its diagnosis. Laparoscopic cholecystectomy was performed in nine cases and open cholecystectomy in 17 cases. The mean postoperative length of stay was significantly shorter in the group of patients with laparoscopy in comparison with the group with open cholecystectomy. Histologic analysis of the gallbladders noted 85% of acute or chronic cholecystis. CONCLUSION: We suggest that cholelithiasis should be carefully sought in the presence of abdominal manifestations in sickle cell patients. We recommend that annual abdominal sonography be performed in sickle cell patients as early as seven years of age and elective cholecystectomy be performed on patients with cholelithiasis.