On-Road Chemical Transformation as an Important Mechanism of NO2 Formation.

Nitrogen dioxide (NO2) not only is linked to adverse effects on the respiratory system but also contributes to the formation of ground-level ozone (O3) and fine particulate matter (PM2.5). Our curbside monitoring data analysis in Detroit, MI, and Atlanta, GA, strongly suggests that a large fraction of NO2 is produced during the "tailpipe-to-road" stage. To substantiate this finding, we designed and carried out a field campaign to measure the same exhaust plumes at the tailpipe-level by a portable emissions measurement system (PEMS) and at the on-road level by an electric vehicle-based mobile platform. Furthermore, we employed a turbulent reacting flow model, CTAG, to simulate the on-road chemistry behind a single vehicle. We found that a three-reaction (NO-NO2-O3) system can largely capture the rapid NO to NO2 conversion (with time scale ≈ seconds) observed in the field studies. To distinguish the contributions from different mechanisms to near-road NO2, we clearly defined a set of NO2/NO x ratios at different plume evolution stages, namely tailpipe, on-road, curbside, near-road, and ambient background. Our findings from curbside monitoring, on-road experiments, and simulations imply the on-road oxidation of NO by ambient O3 is a significant, but so far ignored, contributor to curbside and near-road NO2.

Effects of Cold Temperature and Ethanol Content on VOC Emissions from Light-Duty Gasoline Vehicles.

Emissions of speciated volatile organic compounds (VOCs), including mobile source air toxics (MSATs), were measured in vehicle exhaust from three light-duty spark ignition vehicles operating on summer and winter grade gasoline (E0) and ethanol blended (E10 and E85) fuels. Vehicle testing was conducted using a three-phase LA92 driving cycle in a temperature-controlled chassis dynamometer at two ambient temperatures (-7 and 24 °C). The cold start driving phase and cold ambient temperature increased VOC and MSAT emissions up to several orders of magnitude compared to emissions during other vehicle operation phases and warm ambient temperature testing, respectively. As a result, calculated ozone formation potentials (OFPs) were 7 to 21 times greater for the cold starts during cold temperature tests than comparable warm temperature tests. The use of E85 fuel generally led to substantial reductions in hydrocarbons and increases in oxygenates such as ethanol and acetaldehyde compared to E0 and E10 fuels. However, at the same ambient temperature, the VOC emissions from the E0 and E10 fuels and OFPs from all fuels were not significantly different. Cold temperature effects on cold start MSAT emissions varied by individual MSAT compound, but were consistent over a range of modern spark ignition vehicles.

Temperature effects on particulate emissions from DPF-equipped diesel trucks operating on conventional and biodiesel fuels.

UNLABELLED: Emissions tests were conducted on two medium heavy-duty diesel trucks equipped with a particulate filter (DPF), with one vehicle using a NOx absorber and the other a selective catalytic reduction (SCR) system for control of nitrogen oxides (NOx). Both vehicles were tested with two different fuels (ultra-low-sulfur diesel [ULSD] and biodiesel [B20]) and ambient temperatures (70ºF and 20ºF), while the truck with the NOx absorber was also operated at two loads (a heavy weight and a light weight). The test procedure included three driving cycles, a cold start with low transients (CSLT), the federal heavy-duty urban dynamometer driving schedule (UDDS), and a warm start with low transients (WSLT). Particulate matter (PM) emissions were measured second-by-second using an Aethalometer for black carbon (BC) concentrations and an engine exhaust particle sizer (EEPS) for particle count measurements between 5.6 and 560 nm. The DPF/NOx absorber vehicle experienced increased BC and particle number concentrations during cold starts under cold ambient conditions, with concentrations two to three times higher than under warm starts at higher ambient temperatures. The average particle count for the UDDS showed an opposite trend, with an approximately 27% decrease when ambient temperatures decreased from 70ºF to 20ºF. This vehicle experienced decreased emissions when going from ULSD to B20. The DPF/SCR vehicle tested had much lower emissions, with many of the BC and particle number measurements below detectable limits. However, both vehicles did experience elevated emissions caused by DPF regeneration. All regeneration events occurred during the UDDS cycle. Slight increases in emissions were measured during the WSLT cycles after the regeneration. However, the day after a regeneration occurred, both vehicles showed significant increases in particle number and BC for the CSLT drive cycle, with increases from 93 to 1380% for PM number emissions compared with tests following a day with no regeneration. IMPLICATIONS: The use of diesel particulate filters (DPFs) on trucks is becoming more common throughout the world. Understanding how DPFs affect air pollution emissions under varying operating conditions will be critical in implementing effective air quality standards. This study evaluated particulate matter (PM) and black carbon (BC) emissions with two DPF-equipped heavy-duty diesel trucks operating on conventional fuel and a biodiesel fuel blend at varying ambient temperatures, loads, and drive cycles.

Cold temperature and biodiesel fuel effects on speciated emissions of volatile organic compounds from diesel trucks.

Speciated volatile organic compounds (VOCs) were measured in diesel exhaust from three heavy-duty trucks equipped with modern aftertreatment technologies. Emissions testing was conducted on a chassis dynamometer at two ambient temperatures (-7 and 22 °C) operating on two fuels (ultra low sulfur diesel and 20% soy biodiesel blend) over three driving cycles: cold start, warm start and heavy-duty urban dynamometer driving cycle. VOCs were measured separately for each drive cycle. Carbonyls such as formaldehyde and acetaldehyde dominated VOC emissions, making up ∼ 72% of the sum of the speciated VOC emissions (∑VOCs) overall. Biodiesel use led to minor reductions in aromatics and variable changes in carbonyls. Cold temperature and cold start conditions caused dramatic enhancements in VOC emissions, mostly carbonyls, compared to the warmer temperature and other drive cycles, respectively. Different 2007+ aftertreatment technologies involving catalyst regeneration led to significant modifications of VOC emissions that were compound-specific and highly dependent on test conditions. A comparison of this work with emission rates from different diesel engines under various test conditions showed that these newer technologies resulted in lower emission rates of aromatic compounds. However, emissions of other toxic partial combustion products such as carbonyls were not reduced in the modern diesel vehicles tested.

Carbonaceous aerosols emitted from light-duty vehicles operating on gasoline and ethanol fuel blends.

This study examines the chemical properties of carbonaceous aerosols emitted from three light-duty gasoline vehicles (LDVs) operating on gasoline (e0) and ethanol-gasoline fuel blends (e10 and e85). Vehicle road load simulations were performed on a chassis dynamometer using the three-phase LA-92 unified driving cycle (UDC). Effects of LDV operating conditions and ambient temperature (-7 and 24 °C) on particle-phase semivolatile organic compounds (SVOCs) and organic and elemental carbon (OC and EC) emissions were investigated. SVOC concentrations and OC and EC fractions were determined with thermal extraction-gas chromatography-mass spectrometry (TE-GC-MS) and thermal-optical analysis (TOA), respectively. LDV aerosol emissions were predominantly carbonaceous, and EC/PM (w/w) decreased linearly with increasing fuel ethanol content. TE-GC-MS analysis accounted for up to 4% of the fine particle (PM2.5) mass, showing the UDC phase-integrated sum of identified SVOC emissions ranging from 0.703 µg km(-1) to 18.8 µg km(-1). Generally, higher SVOC emissions were associated with low temperature (-7 °C) and engine ignition; mixed regression models suggest these emissions rate differences are significant. Use of e85 significantly reduced the emissions of lower molecular weight PAH. However, a reduction in higher molecular weight PAH entities in PM was not observed. Individual SVOC emissions from the Tier 2 LDVs and fuel technologies tested are substantially lower and distributed differently than those values populating the United States emissions inventories currently. Hence, this study is likely to influence future apportionment, climate, and air quality model predictions that rely on source combustion measurements of SVOCs in PM.

Managing total knee replacement under value-based payments.

OBJECTIVES: To evaluate opportunity gaps and set outcome goals in knee replacement (KR) between a primary care group taking financial risk for managing its patients and 6 fee-for-service (FFS) orthopedic groups that serve their patients. STUDY DESIGN: The opportunity gap analysis was a cross-sectional evaluation of the outcomes of interest on a risk-adjusted basis using orthopedic groups, the primary care group's patients, and regional comparisons. The impact evaluation was a historical cohort comparison tracking outcomes of interest over the time frame of the intervention. METHODS: Using risk-adjusted Medicare data, we defined opportunity gaps in the following outcomes: density of KR surgery, site of KR surgery, postacute care placement, and complications. RESULTS: Opportunity gap analysis demonstrated the following variation on a regional basis: a 2-fold difference in density of KR, a 3-fold difference in outpatient surgery, and a 2.5-fold difference in institutional postacute care placement. In the impact evaluation comparing 2019 with 2021, the primary care group's patients had reduced density of KR surgeries from 15.5 per 1000 to 13.0 per 1000, an increase in outpatient surgery from 31.0% to 81.6%, and a reduction in institutional postacute care utilization from 16.0% to 6.1%. Less pronounced trends were seen in the region for all Medicare FFS patients. These results were achieved with stable complication rates, which had an observed/expected ratio of 0.61 in 2019 and 0.63 in 2021. CONCLUSIONS: We achieved alignment of incentives through use of performance information with specific goals and promise of referrals to value-based partners. This approach resulted in improved value to patients with no evidence of harm and is translatable to other specialty care and markets.

Morphology and composition of Goldeye (Hiodontidae; Hiodon alosoides) otoliths.

We provide up-to-date morphological and compositional data on otoliths of the osteoglossomorph Goldeye (Hiodon alosoides). Using computed tomography (CT) X-ray, we documented the location of each of the three pairs of otoliths (lapilli, sagittae, and asterisci) in relation to the swim bladder, which extended forward in close proximity to the sagittae and asterisci. The lappili were the largest otoliths in terms of surface area and volume, but the sagittae were highly modified, appearing spiral in shape when viewed dorsally, with a surface area to volume ratio more than double that of the lapilli. Using scanning electron microscopy, the surface of each otolith was viewable in great detail, and small otoconia (~10.5 µm diameter) were observed on each, but were most numerous on the sagittae. On scanning electron micrographs, the sagittae appeared to be bi-lobed, with asymmetrical lobes each oriented in the same general direction. Using neutron and X-ray diffraction methods, we found three polymorphs of calcium carbonate crystals (aragonite, vaterite, and calcite), sometimes all within the same otolith. However, in general, lapilli and sagittae were composed predominately of aragonite whereas asterisci were composed chiefly of vaterite. With these results, we provide information on a unique species, whose inclusion in future studies would benefit our understanding of fish hearing, fish evolution, and fisheries ecology.

Methods of characterizing the distribution of exhaust emissions from light-duty, gasoline-powered motor vehicles in the U.S. fleet.

Mobile sources significantly contribute to ambient concentrations of airborne particulate matter (PM). Source apportionment studies for PM10 (PM < or = 10 microm in aerodynamic diameter) and PM2.5 (PM < or = 2.5 microm in aerodynamic diameter) indicate that mobile sources can be responsible for over half of the ambient PM measured in an urban area. Recent source apportionment studies attempted to differentiate between contributions from gasoline and diesel motor vehicle combustion. Several source apportionment studies conducted in the United States suggested that gasoline combustion from mobile sources contributed more to ambient PM than diesel combustion. However, existing emission inventories for the United States indicated that diesels contribute more than gasoline vehicles to ambient PM concentrations. A comprehensive testing program was initiated in the Kansas City metropolitan area to measure PM emissions in the light-duty, gasoline-powered, on-road mobile source fleet to provide data for PM inventory and emissions modeling. The vehicle recruitment design produced a sample that could represent the regional fleet, and by extension, the national fleet. All vehicles were recruited from a stratified sample on the basis of vehicle class (car, truck) and model-year group. The pool of available vehicles was drawn primarily from a sample of vehicle owners designed to represent the selected demographic and geographic characteristics of the Kansas City population. Emissions testing utilized a portable, light-duty chassis dynamometer with vehicles tested using the LA-92 driving cycle, on-board emissions measurement systems, and remote sensing devices. Particulate mass emissions were the focus of the study, with continuous and integrated samples collected. In addition, sample analyses included criteria gases (carbon monoxide, carbon dioxide, nitric oxide/nitrogen dioxide, hydrocarbons), air toxics (speciated volatile organic compounds), and PM constituents (elemental/organic carbon, metals, semi-volatile organic compounds). Results indicated that PM emissions from the in-use fleet varied by up to 3 orders of magnitude, with emissions generally increasing for older model-year vehicles. The study also identified a strong influence of ambient temperature on vehicle PM mass emissions, with rates increasing with decreasing temperatures.

Outcomes of a conservative care program for knee osteoarthritis through translation of research into practice.

INTRODUCTION: Evidence-based guidelines suggest a conservative, nonsurgical approach as first-line treatment for knee osteoarthritis. However, previous literature has documented underutilization of the fundamental components of condition management emphasized in the guidelines. The intervention aim is to apply organized conservative components of care for knee osteoarthritis in an evidence-based management program through the translation of research into practice with a target to observe meaningful functional improvement in a distinct population. METHODS: The program, modeled after the nonsurgical arm of a randomized, controlled trial, was designed as a single-arm observational cohort study with a pre- and post-program comparison for participants reporting presence of knee osteoarthritis who were attributed to a specific employer's health plan in the United States. The 12-week intervention consisted of condition education, group exercise, and a dietary intervention. RESULTS: Ninety-six participants enrolled in the program, of which 72% completed the protocol. The median change in pre- to post-program Knee Injury and Osteoarthritis Outcome Score values was 10.4 ± 0.8 (Z = 210.5, p < 0.001)-a clinically important change. Secondary outcomes were complementary to the primary outcome. CONCLUSIONS: Results of the program indicate that the clinically significant 3-month findings in the report by Skou et al. (2015) regarding functional improvement can be replicated in an alternate setting. Organizing and offering fundamental components of condition management in a group format with provider oversight could be a feasible and logical component in the continuum of care for knee osteoarthritis, while complementing other secondary management strategies following diagnosis.

Evaluating mobile monitoring of on-road emission factors by comparing concurrent PEMS measurements.

Many countries have adopted portable emissions measurement system (PEMS) testing in their latest regulations to measure real-world vehicular emissions. However, its fleetwide implementation is severely limited by the high equipment costs and lengthy setup procedures, posing a need to develop more cost-effective, efficient emission measurement methods, such as mobile chasing tests. We conducted conjoint PEMS-chasing experiments for twelve heavy-duty diesel vehicles (HDDTs) to evaluate the accuracy of mobile measurement results. Two data processing approaches were integrated to automate the calculations of fuel consumption-based emission factors of nitrogen oxides (NOX). With a total of 245 plume chasing tests conducted, and then averaged by vehicle and road types, we found that the relative errors of vehicle-specific emission factors using an algorithm developed for this project were within approximately ±20% of the PEMS results for all tested vehicles. Stochastic simulations suggested reasonable results could be obtained using fewer chasing tests per vehicle (e.g., 71% for freeways and 94% for local road, equivalent to two chase tests per vehicle). This study improves the understanding of the accuracy of the mobile chasing method, and provides a practical approach for real-time emission measurements for future scaled-up mobile chasing studies.

Traffic and meteorological impacts on near-road air quality: summary of methods and trends from the Raleigh Near-Road Study.

A growing number of epidemiological studies conducted worldwide suggest an increase in the occurrence of adverse health effects in populations living, working, or going to school near major roadways. A study was designed to assess traffic emissions impacts on air quality and particle toxicity near a heavily traveled highway. In an attempt to describe the complex mixture of pollutants and atmospheric transport mechanisms affecting pollutant dispersion in this near-highway environment, several real-time and time-integrated sampling devices measured air quality concentrations at multiple distances and heights from the road. Pollutants analyzed included U.S. Environmental Protection Agency (EPA)-regulated gases, particulate matter (coarse, fine, and ultrafine), and air toxics. Pollutant measurements were synchronized with real-time traffic and meteorological monitoring devices to provide continuous and integrated assessments of the variation of near-road air pollutant concentrations and particle toxicity with changing traffic and environmental conditions, as well as distance from the road. Measurement results demonstrated the temporal and spatial impact of traffic emissions on near-road air quality. The distribution of mobile source emitted gas and particulate pollutants under all wind and traffic conditions indicated a higher proportion of elevated concentrations near the road, suggesting elevated exposures for populations spending significant amounts of time in this microenvironment. Diurnal variations in pollutant concentrations also demonstrated the impact of traffic activity and meteorology on near-road air quality. Time-resolved measurements of multiple pollutants demonstrated that traffic emissions produced a complex mixture of criteria and air toxic pollutants in this microenvironment. These results provide a foundation for future assessments of these data to identify the relationship of traffic activity and meteorology on air quality concentrations and population exposures.

An Evaluation of Reach for a Work Site Implementation of the National Diabetes Prevention Program Focusing on Diet and Exercise.

PURPOSE: Our objective is to evaluate the "reach" component of the Reach Effectiveness Adoption Implementation Maintenance (RE-AIM) framework by comparing prediabetics who were and were not interested in enrolling in a free work site diabetes prevention program (DPP) during the first year of the program. Reach is defined as the proportion of eligible participants who enroll in a health program. DESIGN: A cross-sectional study design was used. SETTING: The setting was a large health system in the Midwest. PARTICIPANTS: Prediabetic health plan enrollees and spouses (N = 2158). MEASURES: An online health survey, annual voluntary biometric screenings delivered by a trained health-care professional using standardized protocols via point-of-care testing, and records from the DPP office were the sources of data for this study. ANALYSIS: Health behaviors and biometric screening results were simultaneously compared using multivariable logistic regression. RESULTS: The study population was 63% female, 79% white, and 16% black, and the mean age was 50.2 years (SD = 10.2). The reach of this program was 10%. Prediabetics were more likely to express interest in the DPP, if they were female (adjusted odds ratio [AOR]: 2.4; 95% confidence interval [95% CI]: 1.55-3.72; P < .001), black (AOR = 2.23; 95% CI: 1.43-3.47; P < .001), older in age (AOR: 1.08; 95% CI: 0.99-1.17; P = .05), or had a high-risk waist circumference (AOR = 1.44; 95% CI: 0.98-2.13; P = .07), lower self-efficacy to make healthy changes (AOR = 0.48; 95% CI: 0.26-0.91; P = .03), and 5 or more doctor visits in the last year (AOR = 2.13; 95% CI: 0.99-4.57; P = .05), after controlling for other covariates. CONCLUSION: Current recruitment and implementation strategies are reaching only a small group of individuals who are not representative of the larger prediabetic population. These findings inform future engagement strategies, and we recommend that public health practitioners evaluate reach to ensure that health promotion programs are of high value.

Depressive symptoms and sex affect completion rates and clinical outcomes in cardiac rehabilitation.

Symptoms of depression are often seen in patients with coronary heart disease. Symptoms appear more commonly in women and are negatively associated with measures of cardiovascular health. Using multiple logistic regression analyses, the authors evaluated the independent effects of depression (as measured by the Beck Depression Inventory [BDI-II]) and sex on cardiac rehabilitation (CR) completion. In addition, in those who completed CR, the authors evaluated whether depressive symptoms and sex affected clinical outcomes. Women as well as participants with enrollment BDI-II scores > or =14 had significantly higher rates of CR noncompletion. Patients with BDI-II scores > or =14 who completed CR achieved significant improvements in lipid profile, body mass index, and exercise capacity regardless of sex. Women and individuals with BDI-II scores > or =14 are at risk for CR noncompletion and should be encouraged to complete CR, because cardiovascular benefits comparable to those seen in men and individuals with low BDI-II scores were achieved when these patients completed the CR program.

Disseminating QI interventions.

BACKGROUND: Partnerships contributed to the success of three diverse health care quality improvement (QI) projects. The Partnerships for Quality (PFQ) Dissemination Planning Tool was used to identify the most appropriate partners to disseminate the QI interventions for three projects, that is, partners most likely to reach and influence the target user(s)-(1) the Catholic Healthcare Partners Heart Failure Partnership, a multisite demonstration of the efficacy of a collaborative approach in the management of heart failure, (2) the Center for Value Purchasing, a collaborative study of the effects of quality incentives on the delivery of chronic disease care, and (3) the New York State Information Dissemination project, a collaborative partnership that targeted dissemination of evidence-based practices in the long term care setting. RESULTS: The RE-AIM model, a construct to aid planning, implementation, and evaluation of health behavior interventions, was used as a framework to examine the impact of partnerships on the three collaborative projects. DISCUSSION: When carefully selected and nurtured, partnerships can substantially facilitate the dissemination and impact of quality improvement projects. The PFQ Dissemination Planning Tool was helpful in identifying and developing strategies for working with partners who could facilitate dissemination of promising practices. The RE-AIM model was a useful framework for examining the impact of the partnerships on the QI projects.

Redefining hospital readmissions to better reflect clinical course of care for heart failure patients.

The prevailing definition of a hospital readmission is a hospital admission that occurs within a specified time frame after discharge from the first or index admission. This definition may be questionable for studies with long or indefinite time frames during which the effect of interventions in the index admission will likely wane, making it less appropriate to classify a later hospitalization as a readmission. The current study proposes an alternative definition of readmission and compares the new definition to the traditional one. The comparison shows that the new method is more conceptually correct because it takes into account the waning effect of the index admission. It can identify readmissions regardless of when they occur. It increases a readmission sample size and thus statistical power.

Variations in speciated emissions from spark-ignition and compression-ignition motor vehicles in California's south coast air basin.

The U.S. Department of Energy Gasoline/Diesel PM Split Study examined the sources of uncertainties in using an organic compound-based chemical mass balance receptor model to quantify the contributions of spark-ignition (SI) and compression-ignition (CI) engine exhaust to ambient fine particulate matter (PM2.5). This paper presents the chemical composition profiles of SI and CI engine exhaust from the vehicle-testing portion of the study. Chemical analysis of source samples consisted of gravimetric mass, elements, ions, organic carbon (OC), and elemental carbon (EC) by the Interagency Monitoring of Protected Visual Environments (IMPROVE) and Speciation Trends Network (STN) thermal/optical methods, polycyclic aromatic hydrocarbons (PAHs), hopanes, steranes, alkanes, and polar organic compounds. More than half of the mass of carbonaceous particles emitted by heavy-duty diesel trucks was EC (IMPROVE) and emissions from SI vehicles contained predominantly OC. Although total carbon (TC) by the IMPROVE and STN protocols agreed well for all of the samples, the STN/IMPROVE ratios for EC from SI exhaust decreased with decreasing sample loading. SI vehicles, whether low or high emitters, emitted greater amounts of high-molecular-weight particulate PAHs (benzo[ghi]perylene, indeno[1,2,3-cd]pyrene, and coronene) than did CI vehicles. Diesel emissions contained higher abundances of two- to four-ring semivolatile PAHs. Diacids were emitted by CI vehicles but are also prevalent in secondary organic aerosols, so they cannot be considered unique tracers. Hopanes and steranes were present in lubricating oil with similar composition for both gasoline and diesel vehicles and were negligible in gasoline or diesel fuels. CI vehicles emitted greater total amounts of hopanes and steranes on a mass per mile basis, but abundances were comparable to SI exhaust normalized to TC emissions within measurement uncertainty. The combustion-produced high-molecular-weight PAHs were found in used gasoline motor oil but not in fresh oil and are negligible in used diesel engine oil. The contributions of lubrication oils to abundances of these PAHs in the exhaust were large in some cases and were variable with the age and consumption rate of the oil. These factors contributed to the observed variations in their abundances to total carbon or PM2.5 among the SI composition profiles.

Temperature and Driving Cycle Significantly Affect Carbonaceous Gas and Particle Matter Emissions from Diesel Trucks.

The present study examines the effects of fuel [an ultralow sulfur diesel (ULSD) versus a 20% v/v soy-based biodiesel-80% v/v petroleum blend (B20)], temperature, load, vehicle, driving cycle, and active regeneration technology on gas- and particle-phase carbon emissions from light and medium heavy-duty diesel vehicles (L/MHDDV). The study is performed using chassis dynamometer facilities that support low-temperature operation (-6.7 °C versus 21.7 °C) and heavy loads up to 12 000 kg. Organic and elemental carbon (OC-EC) composition of aerosol particles is determined using a thermal-optical technique. Gas- and particle-phase semivolatile organic compound (SVOC) emissions collected using traditional filter and polyurethane foam sampling media are analyzed using advanced gas chromatograpy/mass spectrometry methods. Study-wide OC and EC emissions are 0.735 and 0.733 mg/km, on average. The emissions factors for diesel vehicles vary widely, and use of a catalyzed diesel particle filter (CDPF) device generally mutes the carbon particle emissions in the exhaust, which contains ~90% w/w gas-phase matter. Interestingly, replacing ULSD with B20 did not significantly influence SVOC emissions, for which sums range from 0.030 to 9.4 mg/km for the L/MHDDVs. However, both low temperature and vehicle cold-starts significantly increase SVOCs in the exhaust. Real-time particle measurements indicate vehicle regeneration technology did influence emissions, although regeneration effects went unresolved using bulk chemistry techniques. A multistudy comparison of the toxic particle-phase polycyclic aromatic hydrocarbons (PAHs; molecular weight (MW) ≥ 252 amu) in diesel exhaust indicates emission factors that span up to 8 orders of magnitude over the past several decades. This study observes conditions under which PAH compounds with MW ≥ 252 amu appear in diesel particles downstream of the CDPF and can even reach low-end concentrations reported earlier for much larger HDDVs with poorly controlled exhaust streams. This rare observation suggests that analysis of PAHs in particles emitted from modern L/MHDDVs may be more complex than recognized previously.

A Prognostic Indicator for Patients Hospitalized with Heart Failure.

BACKGROUND: Current methods for identifying patients at risk of dying within six months suffer from clinician biases resulting in underestimation of this risk. As a result, patients who are potentially eligible for hospice and palliative care services frequently do not benefit from these services until they are very close to the end of their lives. OBJECTIVE: To develop a prospective prognostic indicator based on actual survival within Centers for Medicare and Medicaid Services (CMS) claims data that identifies patients with congestive heart failure (CHF) who are at risk of six-month mortality. METHODS: CMS claims data from January 1, 2008 to June 30, 2009 were reviewed to find the first hospitalization for CHF patients with episode of care diagnosis-related groups (DRGs) 291, 292, and 293. Univariate and multivariable analyses were used to determine the associations between demographic and clinical factors and six-month mortality. The resulting model was evaluated for discrimination and calibration. RESULTS: The resulting prospective prognostic model demonstrated fair discrimination with an ROC of 0.71 and good calibration with a Hosmer-Lemshow statistic of 0.98. Across all DRGs, 5% of discharged patients had a six-month mortality risk of greater than 50%. CONCLUSION: This prospective approach appears to provide a method to identify patients with CHF who would potentially benefit from a clinical evaluation for referral to hospice care or for a palliative care consult due to high predicted risk of dying within 180 days after discharge from a hospital. This approach can provide a model to match at-risk patients with evidenced-based care in a more consistent manner. This method of identifying patients at risk needs further prospective evaluation to see if it has value for clinicians, increases referrals to hospice and palliative care services, and benefits patients and families.

Clinical profile and outcomes of diabetic and nondiabetic patients in cardiac rehabilitation.

BACKGROUND: Patients with diabetes mellitus have increased risk of cardiovascular disease; however, there are limited data addressing cardiac rehabilitation in these patients. This study assessed the effectiveness of participation in cardiac rehabilitation on clinical outcomes after myocardial infarction and/or revascularization procedures in diabetic and nondiabetic patients. METHODS: Analysis on 1505 patients completing a minimum of 7 weeks of a 12-week cardiac rehabilitation program included fasting lipid profile and glucose, body mass index, and metabolic equivalent time in patients with diabetes (n = 292) and without diabetes (n = 1213). RESULTS: There were significant improvements in total cholesterol, low-density lipoprotein cholesterol (LDL-C) and high-density lipoprotein cholesterol (HDL-C) in each group after cardiac rehabilitation. Diabetic women and nondiabetic men had the greatest improvement in HDL-C, with an improvement of 4.9% in diabetic women (P = .02) and an improvement of 4.1% in nondiabetic men (P < or = .0001). On completion of cardiac rehabilitation, both diabetic and nondiabetic patients were at National Cholesterol Education Program Adult Treatment Panel III goals in total cholesterol, LDL-C, HDL-C, and triglycerides at a higher rate. However, patients with diabetes did not reach National Cholesterol Education Program goals for HDL-C, total cholesterol, and triglycerides as effectively as nondiabetic patients. Exercise capacity improved by 28.1% in diabetic patients after cardiac rehabilitation (P < .0001). Improvement in outcomes in the patients with diabetes occurred without significant change in body mass index. CONCLUSIONS: These results suggest that participation in a comprehensive cardiac rehabilitation program integrates care of patients with chronic conditions such as diabetes to achieve comparable cardiac risk factor reduction as achieved with nondiabetic patients.

Criteria and air-toxic emissions from in-use automobiles in the National Low-Emission Vehicle program.

The U.S. Environmental Protection Agency (EPA) implemented a program to identify tailpipe emissions of criteria and air-toxic contaminants from in-use, light-duty low-emission vehicles (LEVs). EPA recruited 25 LEVs in 2002 and measured emissions on a chassis dynamometer using the cold-start urban dynamometer driving schedule of the Federal Test Procedure. The emissions measured included regulated pollutants, particulate matter, speciated hydrocarbon compounds, and carbonyl compounds. The results provided a comparison of emissions from real-world LEVs with emission standards for criteria and air-toxic compounds. Emission measurements indicated that a portion of the in-use fleet tested exceeded standards for the criteria gases. Real-time regulated and speciated hydrocarbon measurements demonstrated that the majority of emissions occurred during the initial phases of the cold-start portion of the urban dynamometer driving schedule. Overall, the study provided updated emission factor data for real-world, in-use operation of LEVs for improved emissions modeling and mobile source inventory development.