Investigation of roadside fine particulate matter concentration surrounding major arterials in five Southern Californian cities.

The built environment surrounding arterials affects the dispersion of vehicular emissions in urban areas, modifying the potential risks to public health. In order to study the influence of urban morphometry on flow and dispersion of vehicular fine particulate matter emissions, in the summer of 2008 field measurements were performed in major arterials located in five Southern Californian cities with different building geometries. In each city, local mean wind, turbulence, virtual temperature, roadside DustTrak Fine Particles (DTFP) concentration, and traffic flow data were collected in 2-hr measurement periods during morning and evening rush hours and lighter midday traffic, over a period of 3 days. The calculated Monin-Obukhov length, L, suggests that near-neutral and slightly unstable conditions were present at both street and roof levels. The nondimensional forms of turbulent wind and temperature fluctuations show,that the data at street level within the urban canopy can be represented using the Monin-Obukhov similarity theory. Generalized additive models were applied to analyze the impact of meteorological and traffic-related variables on fine particle concentrations at street level Compared to other variables, urban-scale background concentrations were the most important variables in all five models. The results confirmed that turbulent mixing in urban areas dominated the variation of roadside particle concentrations regardless of urban geometry. The distance from the local sites to the nearby monitoring stations affected model performance when urban-scale concentrations were used to predict middle-scale concentrations by generalized additive models (GAMs). A radius ofinfluence for background concentrations was 6-10 km. There were also relationships between concentration and other variables affecting the local components of the concentrations, such as wind direction, sensible heat flux, and vertical wind fluctuation, although the influences were much weaker Implications: The built environment surrounding major arterials affects the dispersion of vehicular emissions in urban areas, modifying the potential risks to public health. Dispersion of pollutants within the urban canopy is governed by flow and turbulence characteristics caused by building morphometry. Current dispersion models used for regulatory purposes have difficulties simulating the flow and dispersion for complex building cases, especially when fine resolution is needed. Urban planning strategies, such as limitation of building height, pedestrian-friendly community design, or zoning of building structures, modify concentrations of vehicular emissions in built environments surrounding major arterials, which may modify health risks for adjacent communities.

Heterogeneous microenvironment analysis to explore the potential regulatory role of endothelial-mesenchymal transition in idiopathic pulmonary fibrosis.

Background: Idiopathic pulmonary fibrosis (IPF) is a chronic and progressive interstitial lung disease mainly caused by excessive proliferation of fibroblasts and activation of myofibroblasts. The cellular microenvironment is mainly composed of different types of cellular components and extracellular matrix (ECM), whose changes directly affect cellular heterogeneity, resulting in immensely complex cellular interactions. However, microenvironment study is mainly focused on the pathological process of tumors, and the microenvironment changes during IPF development remain unclear. Methods: The current study intends to employ IPF-related single-cell sequencing and gene expression profile data to analyze the scores of different cell clusters in the IPF microenvironment, and exploit the underlying interaction between cells to illustrate the fundamental mechanism causing IPF. Results: Our analysis revealed that the amount of endothelial cells was obviously decreased, and the amount of fibroblasts and myofibroblasts was increased during the development of IPF, suggesting a possible endothelial-mesenchymal transition (EndMT) process. Furthermore, we found that the hub genes obtained through IPF-related gene expression profile analysis may play a regulative role in the number and function of endothelial cells and fibroblasts/myofibroblasts during IPF. Conclusions: Our research represents a valuable analysis of the cellular microenvironment, and provides a novel mechanistic insight into the pathobiology of not only EndMT in IPF, but also other traumatic fibrotic disease disorders.

Cost-effectiveness analysis of 4 GLP-1RAs in the treatment of obesity in a US setting.

Background: The number of obese people continues to increase worldwide, and obesity-related complications add to every country's health burden. Consequently, new weight-loss medications, such as glucagon-like peptide-1 receptor agonists (GLP-1RAs), are attracting increasing attention. This study sought to assess the cost effectiveness for weight loss of 4 GLP-1RAs in adult patients with obesity in the United States. Methods: Four GLP-1RA groups that received Liraglutide (1.8 mg QD), Semaglutide (1.0 mg QW), Dulaglutide (1.5 mg QW), or Exenatide (10 µg BID), and one no-treatment group were compared using a decision-tree model. All the estimated parameters were derived from published articles. Quality-adjusted life years (QALYs), costs, and incremental cost-effectiveness ratios (ICERs) were adopted as the study endpoints. We analyzed the results with the willingness-to-pay (WTP) threshold, and conducted deterministic and probabilistic sensitivity analyses. Results: The GLP-1RAs produced effective weight-loss results; however, not all the GLP-1RAs were cost effective compared to no treatment based on a WTP threshold of $195000/QALY. Among the 4 GLP-1RAs, Semaglutide provided a cost-effective strategy with an ICER of $135467/QALY. The sensitivity analyses showed that these results are reliable. Conclusions: Among the 4 GLP-1RAs, Semaglutide was the most cost-effective obesity medication.

Reciprocating flow-based centrifugal microfluidics mixer.

Proper mixing of reagents is of paramount importance for an efficient chemical reaction. While on a large scale there are many good solutions for quantitative mixing of reagents, as of today, efficient and inexpensive fluid mixing in the nanoliter and microliter volume range is still a challenge. Complete, i.e., quantitative mixing is of special importance in any small-scale analytical application because the scarcity of analytes and the low volume of the reagents demand efficient utilization of all available reaction components. In this paper we demonstrate the design and fabrication of a novel centrifugal force-based unit for fast mixing of fluids in the nanoliter to microliter volume range. The device consists of a number of chambers (including two loading chambers, one pressure chamber, and one mixing chamber) that are connected through a network of microchannels, and is made by bonding a slab of polydimethylsiloxane (PDMS) to a glass slide. The PDMS slab was cast using a SU-8 master mold fabricated by a two-level photolithography process. This microfluidic mixer exploits centrifugal force and pneumatic pressure to reciprocate the flow of fluid samples in order to minimize the amount of sample and the time of mixing. The process of mixing was monitored by utilizing the planar laser induced fluorescence (PLIF) technique. A time series of high resolution images of the mixing chamber were analyzed for the spatial distribution of light intensities as the two fluids (suspension of red fluorescent particles and water) mixed. Histograms of the fluorescent emissions within the mixing chamber during different stages of the mixing process were created to quantify the level of mixing of the mixing fluids. The results suggest that quantitative mixing was achieved in less than 3 min. This device can be employed as a stand alone mixing unit or may be integrated into a disk-based microfluidic system where, in addition to mixing, several other sample preparation steps may be included.

[Study of on-board emission measurement for heavy-duty diesel vehicle and its impact with load].

Real world vehicle emission tests were conducted on two heavy-duty diesel trucks on un-loaded and loaded condition by using a portable emission measurement system. By analysis, the results indicate high fuel consumption and emission rates are concentrated on the high speed and acceleration areas of the speed-acceleration emission maps and the areas are much wider on loaded condition. The impact of load on fuel use and emissions will be highest while the vehicle is cruising or accelerating on (30 +/- 2.5) km x h(-1), which are 1.6 - 3.2 times of those on un-loaded condition. Synthetically, the comprehensive fuel consumption and CO, HC, NO(x) emission factors of truck I and truck II on loaded condition are respectively 1.6, 3.5, 1.1, 1.5 times and 1.2, 1.0, 0.9, 1.5 times of those without load. Load has greatest impact on fuel consumption and NO(x) emission and less effect on HC emission. As for the CO emission, it depends on the maintenance of the truck. It can be figured out from the results on two trucks that the impact of same load will be lower on a vehicle with lager type and more powerful engine, which means if one vehicle is loaded on its acceptable range of GVWR, fuel use and emissions caused by heavy loads could be decreased correspondingly.

Organochlorine pesticides in the air around the Taihu Lake, China.

Organochlorine (OC) pesticides have been used broadly in China's past, yet very little is known about their atmospheric concentrations and transport. In this work, air samples were collected in the Taihu Lake Region, China, from July 23 to August 11, 2002, to measure concentrations of OC pesticides in air. The average concentrations of alpha and gamma- hexachlorocyclohexane (HCH), hexachlorobenzene (HCB), heptachlor (HEPT), alpha-endosulfan, p,p'-DDT, p,p'-DDE, p,p'-DDD, and o,p'-DDT in the air were 74 and 46, 47, 53, 307, 124, 212, 36, and 767 pg m(-3), respectively. It was interesting to note that the concentrations of p,p'-DDT, p,p'-DDE, and o,p'-DDT were all very high, even though the use of technical DDT has been banned in China since 1983. Moreover, the average concentration ratios of o,p'-DDT/p,p'-DDT and p,p'-DDE/p,p'-DDT were as high as 6.3 and 1.8. This suggested that there could be an unknown source of DDT-related compounds (DDTs), especially o,p'-DDT and p,p'-DDE. It is very likely that this unknown source was the application of dicofol, an acaricide manufactured from technical DDT and used mainly on cotton fields to treat mites in China. Backward trajectory analysis also provided consistent evidence that the high air concentrations of DDTs were related to trajectories from the area north of the Yangtze River, where cotton fields account for a significant fraction of land use.