| 1. |
|
|
| 2. |
|
|
| 3. |
- Wagner, Robert, et al.
(author)
-
The role of ions in new particle formation in the CLOUD chamber
- 2017
-
In: Atmospheric Chemistry And Physics. - : Copernicus GmbH. - 1680-7316 .- 1680-7324. ; 17:24, s. 15181-15197
-
Journal article (peer-reviewed)abstract
- The formation of secondary particles in the atmosphere accounts for more than half of global cloud condensation nuclei. Experiments at the CERN CLOUD (Cosmics Leaving OUtdoor Droplets) chamber have underlined the importance of ions for new particle formation, but quantifying their effect in the atmosphere remains challenging. By using a novel instrument setup consisting of two nanoparticle counters, one of them equipped with an ion filter, we were able to further investigate the ion-related mechanisms of new particle formation. In autumn 2015, we carried out experiments at CLOUD on four systems of different chemical compositions involving monoterpenes, sulfuric acid, nitrogen oxides, and ammonia. We measured the influence of ions on the nucleation rates under precisely controlled and atmospherically relevant conditions. Our results indicate that ions enhance the nucleation process when the charge is necessary to stabilize newly formed clusters, i.e., in conditions in which neutral clusters are unstable. For charged clusters that were formed by ion-induced nucleation, we were able to measure, for the first time, their progressive neutralization due to recombination with oppositely charged ions. A large fraction of the clusters carried a charge at 1.5 nm diameter. However, depending on particle growth rates and ion concentrations, charged clusters were largely neutralized by ion-ion recombination before they grew to 2.5 nm. At this size, more than 90% of particles were neutral. In other words, particles may originate from ion-induced nucleation, although they are neutral upon detection at diameters larger than 2.5 nm. Observations at Hyytiala, Finland, showed lower ion concentrations and a lower contribution of ion-induced nucleation than measured at CLOUD under similar conditions. Although this can be partly explained by the observation that ion-induced fractions decrease towards lower ion concentrations, further investigations are needed to resolve the origin of the discrepancy.
|
|
| 4. |
- Rodriguez, Alexander J., et al.
(author)
-
Pain, Quality of Life, and Safety Outcomes of Kyphoplasty for Vertebral Compression Fractures : Report of a Task Force of the American Society for Bone and Mineral Research
- 2017
-
In: Journal of Bone and Mineral Research. - : Wiley. - 0884-0431. ; 32:9, s. 1935-1944
-
Journal article (peer-reviewed)abstract
- The relative efficacy and harms of balloon kyphoplasty (BK) for treating vertebral compression fractures (VCF) are uncertain. We searched multiple electronic databases to March 2016 for randomized and quasi-randomized controlled trials comparing BK with control treatment (nonsurgical management [NSM], percutaneous vertebroplasty [PV], KIVA VCF treatment system [Benvenue Medical, Inc., Santa Clara, CA, USA], vertebral body stenting, or other) in adults with VCF. Outcomes included back pain, back disability, quality of life, new VCF, and adverse events (AEs). One reviewer extracted data, a second checked accuracy, and two rated risk of bias (ROB). Mean differences and 95% confidence intervals (CIs) were calculated using inverse-variance models. Risk ratios of new VCF and AE were calculated using Mantel-Haenszel models. Ten unique trials enrolled 1837 participants (age range, 61 to 76 years; 74% female), all rated as having high or uncertain ROB. Versus NSM, BK was associated with greater reductions in pain, back-related disability, and better quality of life (k = 1 trial) that appeared to lessen over time, but were less than minimally clinically important differences. Risk of new VCF at 3 and 12 months was not significantly different (k = 2 trials). Risk of any AE was increased at 1 month (RR = 1.73; 95% CI, 1.36 to 2.21). There were no significant differences between BK and PV in back pain, back disability, quality of life, risk of new VCF, or any AE (k = 1 to 3 trials). Limitations included lack of a BK versus sham comparison, availability of only one RCT of BK versus NSM, and lack of study blinding. Individuals with painful VCF experienced symptomatic improvement compared with baseline with all interventions. The clinical importance of the greater improvements with BK versus NSM is unclear, may be due to placebo effect, and may not counterbalance short-term AE risks. Outcomes appeared similar between BK and other surgical interventions. Well-conducted randomized trials comparing BK with sham would help resolve remaining uncertainty about the relative benefits and harms of BK.
|
|
