27 research outputs found
Nitrate radicals and biogenic volatile organic compounds: oxidation, mechanisms, and organic aerosol
Oxidation of biogenic volatile organic compounds (BVOC) by the nitrate radical (NO_3) represents one of the important interactions between anthropogenic emissions related to combustion and natural emissions from the biosphere. This interaction has been recognized for more than 3 decades, during which time a large body of research has emerged from laboratory, field, and modeling studies. NO_3-BVOC reactions influence air quality, climate and visibility through regional and global budgets for reactive nitrogen (particularly organic nitrates), ozone, and organic aerosol. Despite its long history of research and the significance of this topic in atmospheric chemistry, a number of important uncertainties remain. These include an incomplete understanding of the rates, mechanisms, and organic aerosol yields for NO_3-BVOC reactions, lack of constraints on the role of heterogeneous oxidative processes associated with the NO_3 radical, the difficulty of characterizing the spatial distributions of BVOC and NO_3 within the poorly mixed nocturnal atmosphere, and the challenge of constructing appropriate boundary layer schemes and non-photochemical mechanisms for use in state-of-the-art chemical transport and chemistry–climate models.
This review is the result of a workshop of the same title held at the Georgia Institute of Technology in June 2015. The first half of the review summarizes the current literature on NO_3-BVOC chemistry, with a particular focus on recent advances in instrumentation and models, and in organic nitrate and secondary organic aerosol (SOA) formation chemistry. Building on this current understanding, the second half of the review outlines impacts of NO_3-BVOC chemistry on air quality and climate, and suggests critical research needs to better constrain this interaction to improve the predictive capabilities of atmospheric models
Improved planar amperometric nitric oxide sensor based on platinized platinum anode. 2. Direct real-time measurement of no generated from porcine kidney slices in the presence of l-arginine, l-arginine polymers, protamine
Interaction Between Donor and Recipient Age in Determining the Risk of Chronic Renal Allograft Failure
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/65722/1/j.1532-5415.2002.50002.x.pd
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Factors that identify survival after liver retransplantation for allograft failure caused by recurrent hepatitis C infection
Hepatitis C virus (HCV) is becoming the most common indication for liver retransplantation (ReLTx). This study was a retrospective review of the medical records of liver transplant patients at our institution to determine factors that would identify the best candidates for ReLTx resulting from allograft failure because of HCV recurrence. The patients were divided into 2 groups on the basis of indication for initial liver transplant. Group 1 included ReLTx patients whose initial indication for LTx was HCV. Group 2 included patients who received ReLTx who did not have a history of HCV. We defined chronic allograft dysfunction (AD) as patients with persistent jaundice (> 30 days) beginning 6 months after primary liver transplant in the absence of other reasons. HCV was the primary indication for initial orthotopic liver transplantation (OLT) in 491/1114 patients (44%) from July 1996 to February 2004. The number of patients with AD undergoing ReLTx in Groups 1 and 2 was 22 and 12, respectively. The overall patient and allograft survival at 1 year was 50% and 75% in Groups 1 and 2, respectively (P = .04). The rates of primary nonfunction and technical problems after ReLTx were not different between the groups. However, the incidence of recurrent AD was higher in Group 1 at 32% versus 17% in Group 2 (P = .04). Important factors that predicted a successful ReLTx included physical condition at the time of ReLTx (P = .002) and Child-Turcotte-Pugh score (P = .008). In conclusion, HCV is associated with an increased incidence of chronic graft destruction with a negative effect on long-term results after ReLTx. The optimum candidate for ReLTx is a patient who can maintain normal physical activity. As the allograft shortage continues, the optimal use of cadaveric livers continues to be of primary importance. The use of deceased donor livers in patients with allograft failure caused by HCV remains a highly controversial issue