New particle formation (NPF) substantially contributes to global cloud condensation nuclei (CCN), and their climate impacts. Individual NPF events are also thought to increase local CCN, cloud ...droplet number (CDN), and cloud albedo. High resolution simulations however go against the latter, showing that radiatively important stratiform clouds can experience a systematic and substantial decrease in CDN during and after NPF events. CDN drops because particles too small to act as CCN uptake condensable material, and stunt the growth of particles that would otherwise form droplets. Convective clouds however experience modest increases in CDN—consistent with established views on the NPF‐cloud link. Together, these results reshape our conceptual understanding of NPF impacts on clouds, as the newly discovered duality of responses would drive cloud systems in a fundamentally different manner than thought.
Plain Language Summary
Most studies assume that cloud condensation nuclei (CCN) changes from new particle formation (NPF) events directly reflect cloud droplet number (CDN) responses in clouds and ignore the growth of pre‐existing particles and their contribution to CCN. High resolution state‐of‐the‐art simulations over Europe portray that while convective clouds experience modest increases in CDN, the radiatively important stratiform clouds may present a systematic and substantial decrease in droplet number during and after new particle formation (NPF) events. Consequently, it is evident that NPF exhibits a duality in response—which depending on the local conditions may vitally change the manner in which cloud systems may respond.
Key Points
New particle formation (NPF) events have always been thought to increase the concentration of particles that form cloud droplets thus always lead to climate cooling
Τhrough high resolution modeling it is showed that stratiform clouds influenced by NPF events may experience systematic reductions in droplet leading to local warming from reductions in cloud albedo, while droplet number is always enhanced in convective clouds
These effects combined could bear important impacts on cloud properties and structure following NPF events
A new aerosol dynamics model (DMANx) has been developed that simulates aerosol size/composition distribution and includes the condensation of organic vapors on nanoparticles through the ...implementation of the recently developed volatility basis set framework. Simulations were performed for Hyytiälä (Finland) and Finokalia (Greece), two locations with different organic sources where detailed measurements were available to constrain the new model. We investigate the effect of condensation of organics and chemical aging reactions of secondary organic aerosol (SOA) precursors on ultrafine particle growth and particle number concentration during a typical springtime nucleation event in both locations. This work highlights the importance of the pathways of oxidation of biogenic volatile organic compounds and the production of extremely low volatility organics. At Hyytiälä, organic condensation dominates the growth process of new particles. The low-volatility SOA contributes to particle growth during the early growth stage, but after a few hours most of the growth is due to semi-volatile SOA. At Finokalia, simulations show that organics have a complementary role in new particle growth, contributing 45% to the total mass of new particles. Condensation of organics increases the number concentration of particles that can act as CCN (cloud condensation nuclei) (N100) by 13% at Finokalia and 25% at Hyytiälä during a typical spring day with nucleation. The sensitivity of our results to the surface tension used is discussed.
As sodium–glucose cotransporter-2 inhibitors (SGLT-2is) and glucagon-like peptide-1 receptor agonists (GLP-1RAs) are second-line treatment options in type 2 diabetes mellitus (T2DM), our study sought ...to provide precise effect estimates regarding the role of GLP-1RAs vs SGLT-2is as add-on treatments in patients uncontrolled by metformin monotherapy.
PubMed, the Cochrane Central Register of Controlled Trials (CENTRAL) and ‘grey literature’ were searched from their inception up to December 2019 for randomized controlled trials (RCTs) with durations≥12weeks to evaluate the safety and efficacy of adding a GLP-1RA vs an SGLT-2i in patients with T2DM.
Three eligible RCTs were identified. Administration of GLP-1RAs vs SGLT-2is resulted in significant decreases in HbA1c with no significant impact on either body weight or fasting plasma glucose. GLP-1RA treatment led to a significant increase in odds for achieving an HbA1c<7% compared with SGLT-2is, whereas no difference was detected in body weight reductions of>5%. Significantly greater risk for any hypoglycaemia, nausea and diarrhoea, and lower risk for genital infections, was also observed with GLP-1RAs, while no differences regarding severe hypoglycaemia, treatment discontinuation and impact on blood pressure levels were identified. No other major safety issues arose.
Our meta-analysis suggests that GLP-1RAs provide better glycaemic effects than SGLT-2is in patients with T2DM uncontrolled by metformin, albeit while increasing risk for hypoglycaemia and gastrointestinal adverse events.
PMCAMx-UF, a three-dimensional chemical transport model focusing on the simulation of the ultrafine particle size distribution and composition has been extended with the addition of reactions of ...chemical aging of semivolatile anthropogenic organic vapors, the emissions and chemical aging of intermediate-volatility organic compounds (IVOCs), and the production of extremely low-volatility organic compounds (ELVOCs) by monoterpenes. The model is applied in Europe to quantify the effect of these processes on particle number concentrations. The model predictions are evaluated against both ground measurements collected during the PEGASOS 2012 summer campaign across many stations in Europe and airborne observations by a zeppelin measuring above Po Valley, Italy. PMCAMx-UF reproduces the ground level daily average concentrations of particles with a diameter larger than 100 nm (N.sub.100) with normalized mean error (NME) of 45 % and normalized mean bias (NMB) close to 10 %. For the same simulation, PMCAMx-UF tends to overestimate the concentration of particles with a diameter larger than 10 nm (N.sub.10) with a daily NMB of 23 % and a daily NME of 63 %. The model was able to reproduce more than 75 % of the N.sub.10 and N.sub.100 airborne observations (zeppelin) within a factor of 2.
Abstract
Background
Primary percutaneous coronary intervention (PPCI) is the standard reperfusion treatment in ST-segment elevation myocardial infarction (STEMI). However, PPCI is often complicated ...by microvascular obstruction. Intracoronary thrombolysis (ICT) may mitigate thrombotic burden.
Methods
We conducted, according to the PRISMA statement, the largest meta-analysis of ICT as adjuvant therapy to PPCI. All relevant studies were identified by searching the PubMed, Scopus, Cochrane Library, and Web of Science, with no time or language restriction. The odds ratio (OR) and mean difference (MD) with a 95% confidence interval (CI) were calculated. Studies included STEMI patients undergoing PPCI receiving ICT. Both safety and efficacy outcomes were analyzed. Data were combined using a random-effects model.
Results
Thirteen randomized controlled trials (RCTs) involving a total of 1876 (1014 ICT) patients were included. Compared with the control group, ICT in STEMI patients could reduce the incidence of major adverse cardiac events (MACE) (OR 0.65, 95% CI, 0.48–0.86, P=0.003) and improve 6 months left ventricular ejection fraction (MD 3.78, 95% CI, 1.53–6.02, P=0.0010). Indices of enhanced myocardial microcirculation were more common with ICT Post PCI corrected thrombolysis in myocardial infarction (TIMI) frame count (MD −3.57; 95% CI, −5.00 to −2.14, P<0.00001); myocardial blush grade (MBG) 2/3 (OR 1.76; 95% CI, 1.16–2.69, P=0.008), and complete ST-segment resolution (OR 1.97; 95% CI, 1.33–2.91, P=0.0007). The incidence rate of major bleeding was comparable between the 2 groups (OR 1.27; 95% CI, 0.61–2.63, P=0.53).
Conclusions
Intracoronary thrombolysis was associated with improved MACE and myocardial microcirculation in patients with STEMI undergoing PPCI, without any significant increase in major bleeding. Our meta-analysis suggests that a targeted ICT is safe and potentially effective to improve PPCI. Nonetheless, the above results necessitate verification in a contemporary large RCT.
Funding Acknowledgement
Type of funding sources: None.
The dependence of aerosol acidity on particle size, location, and altitude over Europe during a summertime period is investigated using the hybrid
version of aerosol dynamics in the chemical ...transport model PMCAMx. The pH changes more with particle size in northern and southern Europe owing to
the enhanced presence of non-volatile cations (Na, Ca, K, Mg) in the larger particles. Differences of up to 1–4 pH units are predicted
between sub- and supermicron particles, while the average pH of PM1−2.5 can be as much as 1 unit higher than that of PM1. Most aerosol water over continental Europe is associated with PM1, while coarse particles dominate the water content in the marine and coastal areas due to the relatively higher levels of hygroscopic sea salt. Particles of all sizes become increasingly acidic with altitude (0.5–2.5 units pH decrease over 2.5 km) primarily because of the decrease in aerosol liquid water content (driven by humidity changes) with height. Inorganic nitrate is strongly affected by aerosol pH with the highest average nitrate levels predicted for the PM1−5 range and over locations where the pH exceeds 3. Dust tends to increase aerosol pH for all particle sizes and nitrate concentrations for supermicron range particles. This effect of dust is quite sensitive to its calcium content. The size-dependent pH differences carry important implications for pH-sensitive processes in the aerosol.
The composition of fine particulate matter (PM) in two major Greek cities (Athens and Patras) was measured during two wintertime campaigns, one conducted in 2013 and the other in 2012. A major goal ...of this study is to quantify the sources of organic aerosol (OA) and especially residential wood burning, which has dramatically increased due to the Greek financial crisis. A high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS) was deployed at both sites. PM with diameter less than 1 µm (PM1) consisted mainly of organics (60–75 %), black carbon (5–20 %), and inorganic salts (around 20 %) in both Patras and Athens. In Patras, during evening hours, PM1 concentrations were as high as 100 µg m−3, of which 85 % was OA. In Athens, the maximum hourly value observed during nighttime was 140 µg m−3, of which 120 µg m−3 was OA. Forty to 60 % of the average OA was due to biomass burning for both cities, while the remaining mass originated from traffic (12–17 %), cooking (12–16 %), and long-range transport (18–24 %). The contribution of residential wood burning was even higher (80–90 %) during the nighttime peak concentration periods, and less than 10 % during daytime. Cooking OA contributed up to 75 % during mealtime hours in Patras, while traffic-related OA was responsible for 60–70 % of the OA during the morning rush hour.
Nucleation and subsequent growth are a major source of new particles in many environments, but the pollutants involved and the details of the corresponding processes are still under debate. While ...sulfuric acid has a major role in new particle formation under a lot of conditions, the role of ammonia, amines, and organic vapors is less clear. In most continental areas, new particle formation is quite frequent especially on relatively clean, sunny days when there is some sulfur dioxide available. In parts of the Eastern Mediterranean even if all the previous requirements are satisfied, new particle formation events are relatively rare during summertime.
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