Hygroscopic properties of aerosol particles in the northeastern Atlantic during ACE-2

Measurements of the hygroscopic properties of sub-micrometer atmospheric aerosol particles were performed with hygroscopic tandem differential mobility analysers (H-TDMA) at 5 sites in the subtropical north-eastern Atlantic during the second Aerosol Characterization Experiment (ACE-2) from 16 June to 25 July 1997. Four of the sites were in the marine boundary layer and one was, at least occasionally, in the lower free troposphere. The hygroscopic diameter growth factors of individual aerosol particles in the dry particle diameter range 10−440 nm were generally measured for changes in relative humidity (RH) from <10% to 90%. In the marine boundary layer, growth factors at 90% RH were dependent on location, air mass type and particle size. The data was dominated by a unimodal growth distribution of more-hygroscopic particles, although a bimodal growth distribution including less-hygroscopic particles was observed at times, most often in the more polluted air masses. In clean marine air masses the more-hygroscopic growth factors ranged from about 1.6 to 1.8 with a consistent increase in growth factor with increasing particle size. There was also a tendency toward higher growth factors as sodium to sulphate molar ratio increased with increasing sea-salt contribution at higher wind speeds. During outbreaks of European pollution in the ACE-2 region, the growth factors of the largest particles were reduced, but only slightly. Growth factors at all sizes in both clean and polluted air masses were markedly lower at the Sagres, Portugal site due to more proximate continental influences. The frequency of occurrence of less-hygroscopic particles with a growth factor of ca. 1.15 was greatest during polluted conditions at Sagres. The free tropospheric 50 nm particles were predominately less-hygroscopic, with an intermediate growth factor of 1.4, but more-hygroscopic particles with growth factors of about 1.6 were also frequent. While these particles probably originate from within the marine boundary layer, the less-hygroscopic particles are probably more characteristic of lower free tropospheric air masses. For those occasions when measurements were made at 90% and an intermediate 60% or 70% RH, the growth factor G(RH) of the more-hygroscopic particles could be modelled empirically by a power law expression. For the ubiquitous more-hygroscopic particles, the expressions G(RH)=(1-RH/100)-0.210 for 50 nm Aitken mode particles and G(RH)=(1-RH/100)-0.233 for 166 nm accumulation mode particles are recommended for clean marine air masses in the north-eastern Atlantic within the range 0<RH<95%, and for wind speeds for which the local sea-salt production is small (<ca. 8 m s-1)

IgM anti-malondialdehyde low density lipoprotein antibody levels indicate coronary heart disease and necrotic core characteristics in the Nordic Diltiazem (NORDIL) study and the Integrated Imaging and Biomarker Study 3 (IBIS-3)

Background: Certain immunoglobulins (Ig) are proposed to have protective functions in atherosclerosis. Objectives: We tested whether serum levels of IgG and IgM autoantibodies against malondialdehyde low density lipoprotein (MDA-LDL) are associated with clinical coronary heart disease (CHD) and unfavorable plaque characteristics. Methods: NORDIL was a prospective study investigating adverse cardiovascular outcomes in hypertensive patients. IBIS-3 analyzed lesions in a non-culprit coronary artery with <50% stenosis using radiofrequency intravascular ultrasound (RF-IVUS) and near-infrared spectroscopy (NIRS). Imaging was repeated after a median of 386 days on rosuvastatin. Associations of antibodies with incident CHD and imaging parameters were assessed in the two sub-studies respectively. Findings: From 10,881 NORDIL patients, 87 had serum sampled at baseline and developed CHD over 4.5 years, matched to 227 controls. Higher titers of IgM anti-MDA-LDL had a protective effect on adverse outcomes, with odds ratio 0.29 (0.11, 0.76; p = 0.012; p = 0.016 for trend). Therefore, the effect was explored at the lesional level in IBIS-3. 143 patients had blood samples and RF-IVUS measurements available, and NIRS was performed in 90 of these. At baseline, IgM anti-MDA-LDL levels had a strong independent inverse relationship with lesional necrotic core volume (p = 0.027) and percentage of plaque occupied by necrotic core (p = 0.011), as well as lipid core burden index (p = 0.024) in the worst 4 mm segment. Interpretation: Our study supports the hypothesis that lower circulating levels of IgM anti-MDA-LDL are associated with clinical CHD development, and for the first time relates these findings to atherosclerotic plaque characteristics that are linked to vulnerability

Subsequent Event Risk in Individuals with Established Coronary Heart Disease:Design and Rationale of the GENIUS-CHD Consortium

BACKGROUND: The "GENetIcs of sUbSequent Coronary Heart Disease" (GENIUS-CHD) consortium was established to facilitate discovery and validation of genetic variants and biomarkers for risk of subsequent CHD events, in individuals with established CHD. METHODS: The consortium currently includes 57 studies from 18 countries, recruiting 185,614 participants with either acute coronary syndrome, stable CHD or a mixture of both at baseline. All studies collected biological samples and followed-up study participants prospectively for subsequent events. RESULTS: Enrollment into the individual studies took place between 1985 to present day with duration of follow up ranging from 9 months to 15 years. Within each study, participants with CHD are predominantly of self-reported European descent (38%-100%), mostly male (44%-91%) with mean ages at recruitment ranging from 40 to 75 years. Initial feasibility analyses, using a federated analysis approach, yielded expected associations between age (HR 1.15 95% CI 1.14-1.16) per 5-year increase, male sex (HR 1.17, 95% CI 1.13-1.21) and smoking (HR 1.43, 95% CI 1.35-1.51) with risk of subsequent CHD death or myocardial infarction, and differing associations with other individual and composite cardiovascular endpoints. CONCLUSIONS: GENIUS-CHD is a global collaboration seeking to elucidate genetic and non-genetic determinants of subsequent event risk in individuals with established CHD, in order to improve residual risk prediction and identify novel drug targets for secondary prevention. Initial analyses demonstrate the feasibility and reliability of a federated analysis approach. The consortium now plans to initiate and test novel hypotheses as well as supporting replication and validation analyses for other investigators

An estimate of the number of tropical tree species

The high species richness of tropical forests has long been recognized, yet there remains substantial uncertainty regarding the actual number of tropical tree species. Using a pantropical tree inventory database from closed canopy forests, consisting of 657,630 trees belonging to 11,371 species, we use a fitted value of Fisher’s alpha and an approximate pantropical stem total to estimate the minimum number of tropical forest tree species to fall between ∼40,000 and ∼53,000, i.e. at the high end of previous estimates. Contrary to common assumption, the Indo-Pacific region was found to be as species-rich as the Neotropics, with both regions having a minimum of ∼19,000–25,000 tree species. Continental Africa is relatively depauperate with a minimum of ∼4,500–6,000 tree species. Very few species are shared among the African, American, and the Indo-Pacific regions. We provide a methodological framework for estimating species richness in trees that may help refine species richness estimates of tree-dependent taxa

Phylogenetic classification of the world's tropical forests

Knowledge about the biogeographic affinities of the world’s tropical forests helps to better understand regional differences in forest structure, diversity, composition, and dynamics. Such understanding will enable anticipation of region-specific responses to global environmental change. Modern phylogenies, in combination with broad coverage of species inventory data, now allow for global biogeographic analyses that take species evolutionary distance into account. Here we present a classification of the world’s tropical forests based on their phylogenetic similarity. We identify five principal floristic regions and their floristic relationships: (i) Indo-Pacific, (ii) Subtropical, (iii) African, (iv) American, and (v) Dry forests. Our results do not support the traditional neo- versus paleotropical forest division but instead separate the combined American and African forests from their Indo-Pacific counterparts. We also find indications for the existence of a global dry forest region, with representatives in America, Africa, Madagascar, and India. Additionally, a northern-hemisphere Subtropical forest region was identified with representatives in Asia and America, providing support for a link between Asian and American northern-hemisphere forests.</p

Genetic insights into resting heart rate and its role in cardiovascular disease

Resting heart rate is associated with cardiovascular diseases and mortality in observational and Mendelian randomization studies. The aims of this study are to extend the number of resting heart rate associated genetic variants and to obtain further insights in resting heart rate biology and its clinical consequences. A genome-wide meta-analysis of 100 studies in up to 835,465 individuals reveals 493 independent genetic variants in 352 loci, including 68 genetic variants outside previously identified resting heart rate associated loci. We prioritize 670 genes and in silico annotations point to their enrichment in cardiomyocytes and provide insights in their ECG signature. Two-sample Mendelian randomization analyses indicate that higher genetically predicted resting heart rate increases risk of dilated cardiomyopathy, but decreases risk of developing atrial fibrillation, ischemic stroke, and cardio-embolic stroke. We do not find evidence for a linear or non-linear genetic association between resting heart rate and all-cause mortality in contrast to our previous Mendelian randomization study. Systematic alteration of key differences between the current and previous Mendelian randomization study indicates that the most likely cause of the discrepancy between these studies arises from false positive findings in previous one-sample MR analyses caused by weak-instrument bias at lower P-value thresholds. The results extend our understanding of resting heart rate biology and give additional insights in its role in cardiovascular disease development