Characterizing the Aging of Alphasense NO Sensors in Long-Term Field Deployments.

Low-cost NO sensors have been widely deployed for atmospheric sampling. While their initial performance has been characterized, few studies have examined their long-term degradation. This study focused on the performance of Alphasense low-cost NO sensors (NO2-B42F and NO2-B43F) over 4 years (2016-2020).

Impacts of Modifiable Factors on Ambient Air Pollution: A Case Study of COVID-19 Shutdowns.

COVID-19-related closures offered a novel opportunity to observe and quantify the impact of activity levels of modifiable factors on ambient air pollution in real time. We use data from a network of low-cost Real-time Affordable Multi-Pollutant (RAMP) sensor packages deployed throughout Pittsburgh, Pennsylvania, along with data from Environmental Protection Agency regulatory monitors. The RAMP locations were divided into four site groups based on land use.

Comparing regional stove-usage patterns and using those patterns to model indoor air quality impacts.

Monitoring improved cookstove adoption and usage in developing countries can help anticipate potential health and environmental benefits that may result from household energy interventions. This study explores stove-usage monitor (SUM)-derived usage data from field studies in China (52 stoves, 1422 monitoring days), Honduras (270 stoves, 630 monitoring days), India (19 stoves, 565 monitoring days), and Uganda (38 stoves, 1007 monitoring days). Traditional stove usage was found to be generally similar among four seemingly disparate countries in terms of cooking habits, with average usage of between 171 and 257 minutes per day for the most-used stoves.

The Firepower Sweep Test: A novel approach to cookstove laboratory testing.

Emissions from solid-fuel cookstoves have been linked to indoor and outdoor air pollution, climate forcing, and human disease. Although task-based laboratory protocols, such as the Water Boiling Test (WBT), overestimate the ability of improved stoves to lower emissions, WBT emissions data are commonly used to benchmark cookstove performance, estimate indoor and outdoor air pollution concentrations, estimate impacts of stove intervention projects, and select stoves for large-scale control trials. Multiple-firepower testing has been proposed as an alternative to the WBT and is the basis for a new standardized protocol (ISO 19867-1:2018); however, data are needed to assess the value of this approach.

Rheumatoid nodules: MRI characteristics.

Rheumatoid nodules are not uncommon in patients with rheumatoid arthritis. Two patients with rheumatoid arthritis and rheumatoid nodules are described. The MRI characteristics and enhancement patterns of five nodules are examined.

Silicone synovitis: MR imaging in five patients.

Silicone synovitis is a known complication of silicone implants used in orthopedic surgery for joint reconstruction. It has been studied with routine radiography; however, no report on magnetic resonance imaging abnormalities of this condition exist in the literature. This article reports on five patients with silicone synovitis studied by magnetic resonance imaging.

Hibernoma: MRI appearance of a rare tumor.

We report the features of a hibernoma on magnetic resonance (MR) imaging. The MR characteristics of this lesion were consistent with a complex lipid-containing mass. The mass did not suppress on short tau inversion recovery (STIR) imaging and was clearly not a simple lipoma.

Evaluation of renal masses with contrast-enhanced rapid acquisition spin echo MR imaging.

To assess the use of dynamic contrast-enhanced rapid acquisition spin-echo (RASE) imaging for the detection and characterization of renal masses, we evaluated 18 patients with CT evidence of 67 renal masses. The masses included 58 simple cysts, 8 solid neoplasms, and 1 pseudotumor. Patients were examined with standard spin-echo (SE) pulse sequences including pre- and postcontrast T1-weighted images and noncontrast T2-weighted images as well as pre- and postcontrast RASE images.

Perfluoroctylbromide as a gastrointestinal contrast agent for MR imaging: use with and without glucagon.

The utility of perfluoroctylbromide (PFOB) as a gastrointestinal contrast agent for magnetic resonance (MR) imaging was evaluated with MR examinations performed in 30 subjects (16 healthy volunteers and 14 patients). Transaxial T1-, proton density-, and T2-weighted MR images were acquired in each subject before and after the administration of PFOB. The healthy volunteers each underwent two sets of post-PFOB MR examinations, one before and one after glucagon administration.

Dynamic gadolinium-enhanced rapid acquisition spin-echo MR imaging of the liver.

Rapid acquisition spin-echo (RASE) magnetic resonance (MR) imaging allows for coverage of the entire liver with highly T1-weighted SE images during a single 23-second breath-holding period. The RASE sequence was implemented in conjunction with rapid intravenous injection of gadopentetate dimeglumine to enable performance of dynamic contrast material-enhanced MR imaging of the liver. Prospective evaluation of 24 patients with 62 liver lesions 1 cm or greater in diameter was performed.

"Pseudocoarctation" of the aorta: pitfall on cine MR imaging.

The diagnosis of coarctation of the aorta on cine magnetic resonance imaging is based upon observation of localized narrowing in the region of the aortic isthmus with jet-like signal void areas extending distally. We observed similar findings in 8 of 20 (40%) normal volunteers examined in the sagittal oblique view. These artifactual findings relate primarily to out-of-plane motion of the thoracic aorta during a portion of the cardiac cycle, leading to partial volume averaging with pulmonary air.

Renal masses: evaluation with gradient-echo Gd-DTPA-enhanced dynamic MR imaging.

Dynamic contrast material-enhanced gradient-echo magnetic resonance (MR) imaging was performed on 15 patients with 18 renal masses (seven simple renal cysts, nine renal cell carcinomas, one angiomyolipoma, and one oncocytoma). Fifteen sequential images were obtained while the patients held their breath during a 2.5-3.

Normal signal-void patterns in cardiac cine MR images.

The diagnosis of valvular regurgitation and stenosis with cardiac cine magnetic resonance (MR) imaging is based on observation of localized regions of signal void. However, areas of signal void frequently are present in patients without cardiac abnormalities and may closely resemble signal-void areas that occur secondary to valvular pathologic conditions. Twenty healthy volunteers were prospectively evaluated with gradient-echo cine MR imaging to determine the frequency, distribution, and timing of appearance of regions of signal void in the healthy population.

Rapid acquisition spin-echo (RASE) MR imaging: a new technique for reduction of artifacts and acquisition time.

The rapid acquisition spin-echo (RASE) technique combines a short repetition time, a short echo time, and a single excitation pulse sequence with half-Fourier data sampling. This allows for acquisition of 11 strongly T1-weighted sections during a single 23-second breath-holding period. Measurements obtained from volunteers and with phantoms reveal that RASE images have a lower signal-to-noise ratio and contrast-to-noise ratio than do conventional multiacquisition spin-echo (SE) images due to reduced data acquisition.