Evaluation of the best compromise between the urban air quality monitoring resolution by diffusive sampling and resource requirements.

The need to collect data representative of overall urban pollution is all-important in order to monitor the population exposure. High spatial resolution monitoring using diffusive samplers allows studying of the urban pollutant distribution, thus enabling deeper investigation of their generation and diffusion mechanisms. Nevertheless, such a monitoring campaign has a certain cost. In this study we point out how to find the best compromise between the number of necessary measurements and the affordable costs for monitoring campaigns. We also describe an innovative method for the proper design of a fixed urban monitoring network by means of preliminary high spatial resolution campaigns using diffusive samplers. Four European capital cities (Dublin, Madrid, Paris and Rome) were monitored six times, each time for seven days. Benzene, toluene, ethylbenzene, xylenes (BTEX) and NO(2) concentrations were measured at 146 sites in Dublin, 293 in Madrid, 339 in Paris and 290 in Rome. Multiscale grids have been drawn which ranged in mesh size from 500 m to 2 km. The statistical processing of data produced a twofold result: the creation of isoconcentration maps with geostatistical procedures, and an algorithm aimed at locating the minimum number of sampling sites where the fixed monitoring stations should be placed. Average urban levels estimated on the basis of these selected sites differ by less than 8% from those calculated on the whole populations of the sampled points. The aim of this work is to investigate how far the resolution of a monitoring campaign of urban pollution by diffusive sampling can be reduced, thus making the monitoring less expensive in terms of human and financial resources, while preserving the same quality of the results that could be achieved with a higher resolution. We found that there is no significant loss of information when the resolution of the monitoring grid for BTEX is lowered to a mesh size of 1.85 km, that is a sampling site each 3.4 km(2), and that the minimum number of sampling sites to be used is N = 0.29 A, where A is the urban surface to be monitored (in km(2)). As the spatial distribution of NO(2) is less sensitive to the distance from the emission source than that of BTEX, this relationship could be retained as a valid lower limit for the mesh grid size also for NO(2) monitoring.

Profiling of membrane protein variants in a baculovirus system by coupling cell-surface detection with small-scale parallel expression.

Production of structure-grade mammalian membrane proteins in substantial quantities has been hindered by a lack of methods for effectively profiling multiple constructs expression in higher eukaryotic systems such as insect or mammalian cells. To address this problem, a specialized small-scale eukaryotic expression platform by Thomson Instrument Company (Vertiga-IM) was developed and used in tandem with a Guava EasyCyte microcapillary 96-well cytometer to monitor cell density and health and evaluate membrane protein expression. Two proof of concept experiments were conducted using the human beta(2)-adrenergic receptor (beta(2)AR) and the gap junction protein connexin26 (Cx26) in a baculovirus expression system. First, cell surface expression was used to assess the expression levels of 14 beta(2)AR truncation variants expressed using the Vertiga-IM shaker. Three of these variants were then compared to wild-type beta(2)AR using three metrics: cell surface expression, saturation ligand binding and protein immunoblot analysis of dodecylmaltoside extracted material. Second, a series of systematic Cx26 truncation variants were evaluated for expression by protein immunoblot analysis. The cumulative results for these two systems show that the Vertiga-IM instrument can be used effectively in the parallel insect cell microexpression of membrane protein variants, and that the expression of cell surface molecules as monitored with the Guava EasyCyte instrument can be used to rapidly assess the production of properly folded proteins in the baculovirus expression system. This approach expedites the in vitro evaluation of a large number of mammalian membrane protein variants.

Prediction rule for etiology of vague abdominal pain in the emergency room: utility for imaging triage.

RATIONALE AND OBJECTIVES: To determine the predictive value of clinical parameters in patients with nonspecific abdominal pain undergoing computed tomography (CT) evaluation of the abdomen and pelvis in the emergency room (ER). MATERIALS AND METHODS: A cross-sectional study of a total of 164 sequential abdominal CT exams of the abdomen and pelvis during a 4 month period for nonspecific abdominal pain in the ER setting identified 100 abnormal scans in 164 patients (61 men, 103 women) of average age 46 years (range 4-97). Patient demographic characteristics (age, sex, temperature, white blood cell (WBC) count, and presence of peritoneal signs) were recorded at the time of CT examination. Results of the CT studies were correlated with the clinical data and discharge diagnosis to assess their positive predictive value using ordinal logistic regression. RESULTS: There were 17 cases of appendicitis, 9 cases of diverticulitis, 3 neoplasms, 3 abdominal abscesses, 2 pancreatitis, 2 duodenitis, 5 with fluid collections, 1 buttocks abscess, and 1 epiploic appendagitis were diagnosed with CT, 57 patients had unrelated findings on CT (common but not usually associated with vague pain). A diagnosis of appendicitis correlated with; elevated WBC count (>11.5) ( = 0.002), male sex ( = 0.001), and younger age (<25 years old) ( = 0.002). A positive CT correlated with an elevated WBC >11.5 (OR, 7.7; 95% CI, 3.3-18). The presence of peritoneal signs and fever did not correlate with a positive CT finding and diverticulitis had no predictive variables. Alternative diagnoses were correlated with female sex ( = 0.014). The combination of; age, sex, and WBC count allowed for a prediction rule with Area under the receiver operator curve of 0.92 to be generated. CONCLUSION: An elevated white blood cell (WBC) count is strong evidence of the presence of an inflammatory process. Alternative diagnostic considerations should be entertained in the context of a normal WBC count without strong clinical suspicion, particularly in women. The use of these factors alone allowed the construction of a prediction rule that can be used for CT protocol optimization.