Measurement of Chemical Vapors Emitted from Industrial Sources in an Urban Environment Using Open-path FTIR

A RAM2000 Open-Path (OP) FTIR analyzer was set up to measure ambient air continuously, with 1-min avg, over a 1-mo period at the interface between an industrial area and a residential area (Forest Park) in northwest Portland. There have been numerous complaints from the citizens who live in the Forest Park area about odors and chemicals coming from the industrial area. Twelve chemicals were detected and measured: ammonia, methanol, acetone, propylene glycol methyl ether acetate, n-butyl acetate, isobutanol, 1,1,1,2-tetrafluoroethane, chlorodifluoromethane, tetrachloroethlyene, isopropyl alcohol, 2-butanol, and chloroform. The spectral data was analyzed for 18 other chemicals that are of concern and have appeared in canister samples: benzene, toluene, three isomers of xylene, naphthalene, phenol, CCl 4, dichloromethane, formaldehyde, acetaldehyde, acrolein, styrene, hydrogen cyanide, 1,3-butadiene, 1,2-dibromoethane, 1,2-dichloroethane, and 1,1-dichloroethane. The OP-FTIR technology would be a very valuable tool for monitoring the progress of the Integrated Urban Strategy in reducing the concentrations of the urban hazardous air pollutants. OP-FTIR measurements can produce very large amounts of information on the chemical environment. This is an abstract of a paper presented at the AWMA 97th Annual Conference and Exhibition (Indianapolis, IN 6/22-25/2004)

Baseline visual acuity strongly predicts visual acuity gain in patients with diabetic macular edema following anti-vascular endothelial growth factor treatment across trials

Pravin U Dugel,1,2 Jost Hillenkamp,3 Sobha Sivaprasad,4,5 Jessica Vögeler,6 Marie-Catherine Mousseau,7 Andreas Wenzel,8 Philippe Margaron,8 Ron Hashmonay,8 Pascale Massin9 1Retinal Consultants of Arizona LTD, Retinal Research Institute LLC, Phoenix, AZ, 2USC Eye Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA; 3Department of Ophthalmology, Julius-Maximilians University, Würzburg, Germany; 4NIHR Biomedical Research Centre, Moorfields Eye Hospital, London, 5King’s College Hospital, London, UK; 6Novartis Pharma GmbH, Nürnberg, Germany; 7Novartis Ireland Limited, Dublin, Ireland; 8Novartis Pharma AG, Basel, Switzerland; 9Department of Ophthalmology, Hôpital Lariboisière, Assistance Publique des Hôpitaux de Paris, Université Paris Diderot, Paris, France Objective: This study was designed to evaluate the correlation of baseline visual acuity (VA) with VA outcome in response to anti-vascular endothelial growth factor (VEGF) in diabetic macular edema using a retrospective analysis of nine clinical trials. The result will help assess the relevance of VA gain comparisons across trials. Methods: A correlation analysis was performed between mean baseline VA and VA gain at month 12 for 1,616 diabetic macular edema patients across nine randomized clinical trials (RESOLVE, RISE, RIDE, RESTORE, RETAIN, DRCR.net Protocol I, DA VINCI, VIVID, VISTA) with anti-VEGF treatment regimens ranibizumab 0.5 mg and aflibercept 2 mg. Results: The mean baseline VA ranged from 56.9 to 64.8 Early Treatment Diabetic Retinopathy Study (ETDRS) letters. The mean VA gain at month 12 ranged from 6.8 to 13.1 ETDRS letters across trials. There was a strong inverse correlation between mean baseline VA and VA gain at month 12 (r=-0.85). The mean VA at 12 months plateaued at ~70 (68.5–73.0) ETDRS letters (20/40 Snellen VA equivalent) for the anti-VEGF treatment groups from all trials, regardless of dosing regimens and agents. Conclusion: Cross-trial comparisons based on changes in best-corrected visual acuity should be done cautiously and only after adjusting for best-corrected visual acuity at baseline. Furthermore, the total VA afforded by treatment appears to be subject to a plateau effect, which warrants further exploration. Keywords: aflibercept, anti-vascular endothelial growth factor, best-corrected visual acuity, cross-trial comparison, diabetic macular edema, ranibizuma

FTIR spectroscopy of the atmosphere Part 2. Applications

The basic principles and methods of FTIR spectroscopy of the atmosphere were summarized in our previous paper (1). Thanks to the continuous technical development of FTIR spectroscopy (increasing throughput, dynamic alignment, more sensitive detectors, brighter sources, increasing scanning speed, development of focal plane array detectors, flexible spectral manipulations and data handling, etc.) in the last decade, this method has offered a great number of unique applications. In this review article, attempt to summarize the results of the most significant and frequent applications of FTIR spectroscopy to the study of the atmosphere. The possibilities of techniques applied in this field, the extractive and open path measurement methods, and the in situ IR absorption measurements such as remote sensing using the sun, the sky, or natural hot objects as IR sources of radiation are discussed. We have made a special focus to FTIR emission spectroscopy, the so-called passive technique, since there are a number of originally hot gaseous samples such as volcanic plumes, automobile gases, stack gas plumes, or flames. Most of the subjects discussed in this article can be closely related to environmental analysis of the atmosphere. There is a wide range of atmospheric environmental applications of FTIR spectroscopy; therefore, we have focused our attention in the second part of the article on applications of FTIR spectroscopy in the atmosphere (troposphere) and stratosphere. We have summarized the basic literature in the field of special environmental applications of FTIR spectroscopy, such as power plants, petrochemical and natural gas plants, waste disposals, agricultural, and industrial sites, and the detection of gases produced in flames, in biomass burning, and in flares