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Ship-based measurements of sea spray aerosol (SSA) gradient fluxes in the size range 0.5-47 µm diameter were conducted between 2009 - 2017 in both the Baltic Sea and the North Atlantic Ocean. Measured total SSA fluxes varied between 8.9x103 ± 6.8x105 m-2 s-1 for the Baltic Sea, and 1.0x104 ± 105 m-2 s-1. for the Atlantic Ocean. The analysis uncovered a significant decrease (by a factor of 2.2 in wind speed range 10.5 m s-1 - 14.5 m s-1) in SSA fluxes with chlorophyll-a (Chl-a) concentration higher than 3.5 mg m-3 in the Baltic Sea area. We found statistically significant correlations for both regions of interest between SSA fluxes and various environmental factors including wind speed, wind acceleration, wave age, significant wave height, and wave Reynolds number. Using these factors, we developed separate parameterizations and compared them with previous studies. Additionally, in both measurement regions we observed weak correlations between SSA fluxes and air and water temperature, as well as atmospheric stability. Comparing the Baltic Sea and North Atlantic, we noted distinct emission behaviours, with higher emissions in the Baltic Sea at low wave age values compared to the Atlantic Ocean. This study represents the first comparative analysis of SSA flux measurements using the same methodology in these contrasting marine environments. [ABSTRACT FROM AUTHOR]

To bridge the gap between in situ and laboratory estimates of sea spray aerosol (SSA) production fluxes, we conducted two research campaigns in the vicinity of an eddy covariance (EC) flux tower on the island of Östergarnsholm in the Baltic Sea during May and August 2021. To accomplish this, we performed EC flux measurements simultaneously with laboratory measurements using a plunging jet sea spray simulation chamber containing local seawater sampled close to the footprint of the flux tower. We observed a log-linear relationship between wind speed and EC-derived SSA emission fluxes, a power-law relationship between significant wave height and EC-derived SSA emission fluxes, and a linear relationship between wave Reynolds number and EC-derived SSA emission fluxes, all of which are consistent with earlier studies. Although we observed a weak negative relationship between particle production in the sea spray simulation chamber and seawater chlorophyll-α concentration and a weak positive relationship with the concentration of fluorescent dissolved organic matter in seawater, we did not observe any significant impact of dissolved oxygen on particle production in the chamber. To obtain an estimate of the size-resolved emission spectrum for particles with dry diameters between 0.015 and 10 μm, we combined the estimates of SSA particle production fluxes obtained using the EC measurements and the chamber measurements in three different ways: 1) using the traditional continuous whitecap method, 2) using air entrainment measurements, and 3) simply scaling the chamber data to the EC fluxes. In doing so, we observed that the magnitude of the EC-derived emission fluxes compared relatively well to the magnitude of the fluxes obtained using the chamber air entrainment method, as well as the previous flux measurements of Nilsson et al. (2021) and the parameterisations of Mårtensson et al. (2003) and Salter et al. (2015). As a result of these measurements, we have derived a wind speed-dependent and wave state-dependent SSA parameterization for particles with dry diameters between 0.015 and 10 μm for low-salinity waters such as the Baltic Sea, thus providing a more accurate estimation of SSA production fluxes. [ABSTRACT FROM AUTHOR]

To improve our understanding of the impact of sea salt aerosols (SSA) on the Earth's climate, it is critical to understand the physical mechanisms which determine the size‐resolved SSA production flux. Of the factors affecting SSA emissions, seawater salinity has perhaps received the least attention in the literature and previous studies have produced conflicting results. Here, we present a series of laboratory experiments designed to investigate the role of salinity on aerosol production from artificial seawater using a continuous plunging jet. During these experiments, the aerosol and surface bubble size distributions were monitored while the salinity was decreased from 35 to 0 g kg−1. Three distinct salinity regimes were identified: (a) A high salinity regime, 10–35 g kg−1, where lower salinity resulted in only minor reductions in particle number flux but notable reductions in particle volume flux; (b) an intermediate salinity regime, 5–10 g kg−1, with a local maximum in particle number flux; (c) a low salinity regime, <5 g kg−1, characterized by a rapid decrease in particle number flux at lower salinities and dominated by small particles and larger bubbles. We discuss the implications of our results through comparison of the size‐resolved aerosol flux and the surface bubble population at different salinities. Finally, by varying the seawater temperature at three specific salinities we have also developed a simple parameterization of the particle production flux as a function of seawater temperature and salinity. The range of seawater salinity and temperature studied is representative of the global oceans and lower salinity water bodies such as the Baltic Sea. Key Points: Sea salt aerosol concentration and size distributions in the head space of the chamber depended on the seawater salinity and temperatureSea salt particle production was linearly dependent on salinity between 10 and 35 g kg−1 and below 5 g kg−1 and peaked between 5 and 10 g kg−1Temperature affected the sea salt particle number flux with the same sign at all salinities, but the magnitude differed with salinity [ABSTRACT FROM AUTHOR]

Physical inactivity is a risk factor for insulin resistance. We examined the effect of 9 days of bed rest on basal and insulin-stimulated expression of genes potentially involved in insulin action by applying hypothesis-generating microarray in parallel with candidate gene real-time PCR approaches in 20 healthy young men. Furthermore, we investigated whether bed rest affected DNA methylation in the promoter region of the peroxisome proliferator-activated receptor-[gamma] coactivator-1[alpha] (PPARGC1A) gene. Subjects were reexamined after 4 wk of retraining. We found that bed rest induced insulin resistance and altered the expression of more than 4,500 genes. These changes were only partly normalized after 4 wk of retraining. Pathway analyses revealed significant downregulation of 34 pathways, predominantly those of genes associated with mitochondrial function, including PPARGC1A. Despite induction of insulin resistance, bed rest resulted in a paradoxically increased response to acute insulin stimulation in the general expression of genes, particularly those involved in inflammation and endoplasmatic reticulum (ER) stress. Furthermore, bed rest changed gene expressions of several insulin resistance and diabetes candidate genes. We also observed a trend toward increased PPARGC1A DNA methylation after bed rest. We conclude that impaired expression of PPARGC1A and other genes involved in mitochondrial function as well as a paradoxically increased response to insulin of genes involved in inflammation and ER stress may contribute to the development of insulin resistance induced by bed rest. Lack of complete normalization of changes after 4 wk of retraining underscores the importance of maintaining a minimum of daily physical activity. bed rest; peroxisome proliferator-activated receptor-[gamma] coactivator-1[alpha]; gene expression; mitochondria doi: 10.1152/ajpendo.00590.2009.

Protein microarrays are powerful tools to quantify and characterize proteins in multiplex assays. They have great potential within clinical diagnostics and prognostics, as they minimize consumption of both analyte and biological sample. Assays that do not require labeling of the biological specimen, henceforth called label-free, are vital for ease of clinical sample processing. Here, we evaluate two label-free techniques, reverse-phase and sandwich antibody assays, using microarrays on high-performance porous silicon surfaces and fluorescence detection. In view of increasing interest in reverse microarrays, this paper focuses on analytical sensitivity of the reverse assays compared to the more complex but highly sensitive sandwich assay. Sensitivity, linear range, and reproducibility of the two assays were compared using prostatespecific antigen (PSA) in buffer. The sandwich assay displayed 5 orders of magnitude lower detection limit (0.7 ng/mL) compared to the reverse assay (70 [micro]g/mL). PSA at 50 nM (1.5 [micro]g/mL) in cell lysates was detected by the sandwich assay but not by the reverse assay, demonstrating again a far lower detection limit for sandwich microarrays. In independent assay runs of PSA spiked in female serum, the sandwich assay had good linearity ([R.sup.2] > 0.99) and reproducibility (coefficient of variation [less than or equal to] 15%), and the detection limit could be improved to 0.14 ng/mL. Without further signal amplification, the sandwich assay would be our choice for PSA analysis of clinical samples using a microarray technology platform.