Explore the vast range of titles available.

Breaking waves on the ocean surface generate air bubbles that scavenge organic matter from the surrounding sea water. When injected into the atmosphere, these bubbles burst, yielding sea spray aerosols enriched in organic matter, relative to the sea water. Downwind of plankton blooms, the organic carbon content of sea spray aerosol is weakly correlated with satellite-derived measurements of chlorophyll a levels, a measure of phytoplankton biomass. This correlation has been used in large-scale models to calculate the organic enrichment in sea spray aerosol. Here, we assess the relationship between the organic carbon content of sea water and freshly emitted sea spray aerosol in the presence and absence of plankton blooms in the North Atlantic Ocean and the coastal waters of California. The organic carbon content of freshly emitted sea spray aerosol was similar in all regions sampled, despite significant differences in seawater chlorophyll a levels. The proportion of freshly emitted aerosols that served as cloud condensation nuclei at a given supersaturation was also similar across sampling sites. The large reservoir of organic carbon in surface sea water remained relatively constant across the regions sampled, and independent of variations in chlorophyll a concentrations. We suggest that this reservoir is responsible for the organic carbon enrichment of freshly emitted sea spray aerosol, overwhelming any influence of local biological activity as measured by chlorophyll a levels. Breaking waves on the ocean surface generate air bubbles that yield sea spray aerosols when released to the atmosphere. Measurements of sea spray aerosols in the North Atlantic Ocean and the coastal waters of California suggest that the surface water organic carbon reservoir is responsible for the organic carbon enrichment of freshly emitted sea spray aerosol.

Sea spray aerosols impact Earth’s radiation balance by directly scattering solar radiation. They also act as cloud condensation nuclei, thereby altering cloud properties including reflectivity, lifetime and extent. The influence of sea spray aerosol on cloud properties is thought to be particularly strong over remote ocean regions devoid of continental particles. Yet the contribution of sea spray aerosol to the population of cloud condensation nuclei in the marine boundary layer remains poorly understood. Here, using a lognormal-mode-fitting procedure, we isolate sea spray aerosols from measurements of particle size and abundance over the Pacific, Southern, Arctic and Atlantic oceans to determine the contribution of sea spray aerosol to the population of cloud condensation nuclei in the marine boundary layer. On a global basis, with the exception of the high southern latitudes, sea spray aerosol makes a contribution of less than 30% to the cloud condensation nuclei population for air that is supersaturated at 0.1 to 1.0%—the supersaturation range typical of marine boundary layer clouds. Instead, the cloud condensation nuclei population between 70° S and 80° N is composed primarily of non-sea-salt sulfate aerosols, due to large-scale meteorological features that result in entrainment of particles from the free troposphere. Sea spray aerosols are thought to alter cloud properties in remote ocean regions. Aerosol analyses over four ocean regions reveal that these aerosols represent less than 30% of cloud condensation nuclei in typical marine boundary layer clouds.

Lanthanum hexaboride (LaB6) has become a material of intense interest in recent years due to its low work function, thermal stability and intriguing optical properties. LaB6 is also a semiconductor plasmonic material with the ability to support strong plasmon modes. Some of these modes uniquely stretch into the infrared, allowing the material to absorb around 1000 nm, which is of great interest to the window industry. It is well known that the plasmon of LaB6 can be tuned by controlling particle size and shape. In this work, we explore the options available to further tune the optical properties by describing how metal vacancies and Eu doping concentrations are additional knobs for tuning the absorbance from the near-IR to far-IR in La1−xEuxB6 (x = 0, 0.2, 0.5, 0.8, and 1.0). We also report that there is a direct correlation between Eu concentration and metal vacancies within the Eu1−xLaxB6.

Black carbon (BC) mass emission factors (EFBC; g BC (kg fuel)−1) from a variety of ocean-going vessels have been determined from measurements of BC and carbon dioxide (CO2) concentrations in ship plumes intercepted by the R/V Atlantis during the 2010 California Nexus (CalNex) campaign. The ships encountered were all operating within 24 nautical miles of the California coast and were utilizing relatively low sulphur fuels (average fuel sulphur content of 0.4%, 0.09% and 0.03% for vessels operating slow-speed, medium-speed and high-speed diesel engines, respectively). Black carbon concentrations within the plumes, from which EFBC values are determined, were measured using four independent instruments: a photoacoustic spectrometer and a particle soot absorption photometer, which measure light absorption, and a single particle soot photometer and soot particle aerosol mass spectrometer, which measure the mass concentration of refractory BC directly. These measurements have been used to assess the level of agreement between these different techniques for the determination of BC emission factors from ship plumes. Also, these measurements greatly expand upon the number of individual ships for which BC emission factors have been determined during real-world operation. The measured EFBC's have been divided into vessel type categories and engine type categories, from which averages have been determined. The geometric average EFBC (excluding outliers) determined from over 71 vessels and 135 plumes encountered was 0.31 0.31 g BC (kg fuel)−1, where the standard deviation represents the variability between individual vessels. The most frequent engine type encountered was the slow-speed diesel (SSD), and the most frequent SSD vessel type was the cargo ship sub-category. Average and median EFBC values from the SSD category are compared with previous observations from the Texas Air Quality Study (TexAQS) in 2006, during which the ships encountered were predominately operating on high-sulphur fuels (average fuel sulphur content of 1.6%). There is a statistically significant difference between the EFBC values from CalNex and TexAQS for SSD vessels and for the cargo and tanker ship types within this engine category. The CalNex EFBC values are lower than those from TexAQS, suggesting that operation on lower sulphur fuels is associated with smaller EFBC values.

Emissions factors (EFs) for gas and sub-micron particle-phase species were measured in intercepted plumes as a function of vessel speed from an underway research vessel, the NOAA ship Miller Freeman, operating a medium-speed diesel engine on low-sulfur marine gas oil (fuel sulfur content ~0.1% by weight). The low-sulfur fuel in use conforms to the MARPOL fuel sulfur limit within emission control areas set to take effect in 2015 and to California-specific limits set to take effect in 2014. For many of the particle-phase species, EFs were determined using multiple measurement methodologies, allowing for an assessment of how well EFs from different techniques agree. The total sub-micron PM (PM1) was dominated by particulate black carbon (BC) and particulate organic matter (POM), with an average POM / BC ratio of 1.3. Consideration of the POM / BC ratios observed here with literature studies suggests that laboratory and in-stack measurement methods may overestimate primary POM EFs relative to those observed in emitted plumes. Comparison of four different methods for black carbon measurement indicates that careful attention must be paid to instrument limitations and biases when assessing EFBC. Particulate sulfate (SO42−) EFs were extremely small and the particles emitted by Miller Freeman were inefficient as cloud condensation nuclei (CCN), even at high super saturations, consistent with the use of very low-sulfur fuel and the overall small emitted particle sizes. All measurement methodologies consistently demonstrate that the measured EFs (fuel mass basis) for PM1 mass, BC and POM decreased as the ship slowed. Particle number EFs were approximately constant across the speed change, with a shift towards smaller particles being emitted at slower speeds. Emissions factors for gas-phase CO and formaldehyde (HCHO) both increased as the vessel slowed, while EFs for NOx decreased and SO2 EFs were approximately constant.

The sea breeze/land breeze diurnal circulation within the Los Angeles Basin and adjacent waters transports marine air into the basin during the day and urban air to Santa Monica Bay during the night. Nitryl chloride, ClNO2 is a nocturnal trace gas formed from the heterogeneous reaction of dinitrogen pentaoxide (N2O5) with chloride containing aerosol. Its photolysis after sunrise produces atomic chlorine radicals and regenerates NO2, both of which may increase ozone production. Mixing of the chloride source from marine sea salt with the urban NOx source in Los Angeles provides conditions ideal for the production of ClNO2. This paper presents an analysis using a wind profiler on the coast and measurements of ClNO2 and its precursors made from both ship and aircraft to assess the prevailing meteorological conditions important for ClNO2 production in this region, with a particular focus on the production over water within the land breeze phase of the circulation. A box model is used to calculate an upper limit to the amount of ClNO2 capable of being produced strictly over Santa Monica Bay during the land breeze. On three out of the four nights of ClNO2 measurements in Santa Monica Bay, the ClNO2 exceeds the upper limit calculated using the box model and shows that the majority of the ClNO2 is produced over the city and transported to Santa Monica Bay by the land breeze. This ClNO2 transport suggests the sea breeze more efficiently transports aerosol chloride inland than land breeze transports NOx offshore. Key Points The land breeze transports urban air off shore during the night The urban plume in Santa Monica Bay contains ppb levels of ClNO2 ClNO2 is produced over Los Angeles and transported to Santa Monica Bay

To characterize dietary patterns among a diverse sample of older adults (≥ 65 years). Cross-sectional. Five counties in west central Alabama. Community-dwelling Medicare beneficiaries (N=416; 76.8 ±5.2 years, 56% female, 39% African American) in the University of Alabama at Birmingham (UAB) Study of Aging. Dietary data collected via three, unannounced 24-hour dietary recalls was used to identify dietary patterns. Foods were aggregated into 13 groups. Finite mixture modeling (FMM) was used to classify individuals into three dietary patterns. Differences across dietary patterns for nutrient intakes, sociodemographic, and anthropometric measurements were examined using chi-square and general linear models. Three dietary patterns were derived. A “More healthful” dietary pattern, with relatively higher intakes of fruit, vegetables, whole grains, eggs, nuts, legumes and dairy, was associated with lower energy density, higher quality diets as determined by Healthy Eating Index (HEI)-2005 scores and higher intakes of fiber, folate, vitamins C and B6, calcium, iron, magnesium, and zinc. The “Westernlike” pattern was defined by an intake of starchy vegetables, refined grains, meats, fried poultry and fish, oils and fats and was associated with lower HEI-2005 scores. The “Low produce, high sweets” pattern was characterized by high saturated fat, and low dietary fiber and vitamin C intakes. The strongest predictors of better diet quality were female gender and non-Hispanic white race. The dietary patterns identified may provide a useful basis on which to base dietary interventions targeted at older adults. Examination of nutrient intakes regardless of the dietary pattern suggests that older adults are not meeting nutrient recommendations and should continue to be encouraged to choose high quality diets.

The glycoprotein YKL-40 (CHI3L1) is a secreted chitinase family protein that induces angiogenesis, cell survival, and cell proliferation, and plays roles in tissue remodeling and immune regulation. It is expressed primarily in cells of mesenchymal origin, is overexpressed in numerous aggressive carcinomas and sarcomas, but is rarely expressed in normal ectodermal tissues. Bone marrow-derived mesenchymal stem cells (MSCs) can be induced to differentiate into various mesenchymal tissues and trans-differentiate into some non-mesenchymal cell types. Since YKL-40 has been used as a mesenchymal marker, we followed YKL-40 expression as undifferentiated MSCs were induced to differentiate into bone, cartilage, and neural phenotypes. Undifferentiated MSCs contain significant levels of YKL-40 mRNA but do not synthesize detectable levels of YKL-40 protein. MSCs induced to differentiate into chondrocytes and osteocytes soon began to express and secrete YKL-40 protein, as do ex vivo cultured chondrocytes and primary osteocytes. In contrast, MSCs induced to trans-differentiate into neurons did not synthesize YKL-40 protein, consistent with the general absence of YKL-40 protein in normal CNS parenchyma. However, these trans-differentiated neurons retained significant levels of YKL-40 mRNA, suggesting the mechanisms which prevented YKL-40 translation in undifferentiated MSCs remained in place, and that these trans-differentiated neurons differ in at least this way from neurons derived from neuronal stem cells. Utilization of a differentiation protocol containing β-mercaptoethanol resulted in cells that expressed significant amounts of intracellular YKL-40 protein that was not secreted, which is not seen in normal cells. Thus the synthesis of YKL-40 protein is a marker for MSC differentiation into mature mesenchymal phenotypes, and the presence of untranslated YKL-40 mRNA in non-mesenchymal cells derived from MSCs reflects differences between differentiated and trans-differentiated phenotypes.

The prevalence of obesity-related adverse health outcomes is increasing among older adults. Because it is thought that nutrition plays an important role in successful aging, there has been considerable interest in the association between dietary patterns of older adults and obesity-related health outcomes. This study examined the association between dietary patterns and mortality and prevalence of obesity-related health outcomes, namely cardiovascular disease (CVD), type 2 diabetes mellitus, hypertension, and metabolic syndrome (MetSyn), over a 5-year follow-up period in adults aged 75 years or greater. A longitudinal observational study with cross-sectional dietary assessment. Rural Central Pennsylvania. Community-dwelling older adults (N = 449; 76.5 years old; 57% female). Multiple, unannounced, 24-hour dietary recalls were used to collect dietary intake. Cluster analysis was used to derive dietary patterns. Prevalence of CVD, diabetes mellitus, hypertension, and MetSyn was extracted from outpatient electronic medical records. Logistic regression was used to examine the associations between dietary patterns and health outcomes and mortality. ‘Sweets and Dairy', ‘Health-Conscious' and ‘Western' dietary patterns were identified. Compared to the ‘Health-Conscious' pattern, those in the ‘Sweets and Dairy' pattern had increased odds of hypertension over the follow-up period; adjusted odds ratio (95% CI) was 2.18 (1.11–4.30). No significant associations were found for CVD, diabetes mellitus, MetSyn or mortality with dietary patterns. These findings support the potential value of healthy dietary patterns in the management of hypertension in older adults. We did not observe any other strong associations between dietary patterns and health outcomes or mortality in persons ≥ 75 years of age; thus failing to support the use of overly restrictive diet prescriptions for older persons, especially where food intake may be inadequate.

The spectral deconvolution algorithm (SDA) and SDA+ (extended SDA) methodologies can be employed to separate the fine and coarse mode extinction coefficients from measured total aerosol extinction coefficients, but their common use is currently limited to AERONET (AErosol RObotic NETwork) aerosol optical depth (AOD). Here we provide the verification of the SDA+ methodology on a non-AERONET aerosol product, by applying it to fine and coarse mode nephelometer and particle soot absorption photometer (PSAP) data sets collected in the marine boundary layer. Using data sets collected on research vessels by NOAA-PMEL(National Oceanic and Atmospheric Administration – Pacific Marine Environmental Laboratory), we demonstrate that with accurate input, SDA+ is able to predict the fine and coarse mode scattering and extinction coefficient partition in global data sets representing a range of aerosol regimes. However, in low-extinction regimes commonly found in the clean marine boundary layer, SDA+ output accuracy is sensitive to instrumental calibration errors. This work was extended to the calculation of coarse and fine mode scattering coefficients with similar success. This effort not only verifies the application of the SDA+ method to in situ data, but by inference verifies the method as a whole for a host of applications, including AERONET. Study results open the door to much more extensive use of nephelometers and PSAPs, with the ability to calculate fine and coarse mode scattering and extinction coefficients in field campaigns that do not have the resources to explicitly measure these values.