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UCLALES-SALSA is a detailed high-resolution model for studying aerosol-cloud interactions in shallow clouds. The model is based on a large eddy simulator UCLALES which was coupled with a sectional aerosol-cloud microphysics module SALSA. The model was recently coupled with a Secondary Organic Aerosol (SOA) formation module. The SOA module contains lumped Volatile Organic Compound (VOC) categories such as biogenic monoterpenes and isoprene, and anthropogenic aromatics. Their oxidation produces Semi-Volatile Organic Compounds (SVOCs), which partitioning between vapor and particle phases. The partitioning is modelled using a Volatility Basis Set (VBS) approach. The module also contains aqueous-phase SOA (aqSOA) formation.The model was tested using a LES setup based on in-situ stratocumulus cloud observations from Kuopio, Finland. The observed low aerosol number concentrations and high aerosol organic factions indicated that SOA formation could have a significant impact on cloud properties. First, by allowing the partitioning of SVOCs the condensed-phase organic aerosol (SOA) concentration becomes temperature dependent. In this case the temperature decreased due to radiative cooling, which increased the SOA mass and the cloud droplet number concentration (CDNC). Surface VOC emissions are important for maintaining SOA production as the reactive VOCs are otherwise consumed rapidly. Thanks to the effective vertical mixing, surface emissions had direct impact on CDNC. Finally, the impact of aqSOA formation depends mainly on anthropogenic emissions because VOC emissions from local boreal forests are dominated by monoterpenes which are not effective aqSOA precursors., The 28th IUGG General Assembly (IUGG2023) (Berlin 2023)

There are disadvantages in Elastic Stable Intramedullary Nailing (ESIN) of forearm-shaft fractures, such as the need of implant removal. Biodegradable Intramedullary Nailing (BIN) is a new technique developed for these fractures. We hypothesized that there is no difference in rotational ROM between the patients treated by BIN vs. ESIN. A randomized, controlled clinical trial included patients, aged 5–15 years, requiring surgery for forearm-shaft fractures. Biodegradable polylactide-co-glycolide (PLGA) nails (Activa IM-Nail™, Bioretec Ltd., Finland) were used in 19 and titanium nails (TEN®, SynthesDePuy Ltd., USA) in 16 patients. Rotational ROM of forearm after two years was the primary outcome. Elbow and wrist ROM, pain and radiographic bone healing were secondary outcomes. Forearm rotation was mean 162° and 151° in BIN and ESIN groups, respectively (P = 0.201). No difference between the groups was found in any other ROMs. Three cases in the ESIN vs. none in the BIN group reported pain (P = 0.113). There was no clinically significant residual angulation in radiographs. Two adolescents in the BIN group vs. none in the ESIN (P = 0.245) were excluded because of implant failure; another two with complete bone union suffered from re-injury. Therefore, satisfactory implant stability among older children needs to be studied.

International audience; We report comprehensive, demonstrably contaminant-free measurements of binary particle formation rates by sulfuric acid and water for neutral and ion-induced pathways conducted in the European Organization for Nuclear Research Cosmics Leaving Outdoor Droplets chamber. The recently developed Atmospheric Pressure interface-time of flight-mass spectrometer was used to detect contaminants in charged clusters and to identify runs free of any contaminants. Four parameters were varied to cover ambient conditions: sulfuric acid concentration (105 to 109 mol cm−3), relative humidity (11% to 58%), temperature (207 K to 299 K), and total ion concentration (0 to 6800 ions cm−3). Formation rates were directly measured with novel instruments at sizes close to the critical cluster size (mobility size of 1.3 nm to 3.2 nm). We compare our results with predictions from Classical Nucleation Theory normalized by Quantum Chemical calculation (QC-normalized CNT), which is described in a companion paper. The formation rates predicted by the QC-normalized CNT were extended from critical cluster sizes to measured sizes using the UHMA2 sectional particle microphysics model. Our results show, for the first time, good agreement between predicted and measured particle formation rates for the binary (neutral and ion-induced) sulfuric acid-water system. Formation rates increase with RH, sulfuric acid, and ion concentrations and decrease with temperature at fixed RH and sulfuric acid concentration. Under atmospheric conditions, neutral particle formation dominates at low temperatures, while ion-induced particle formation dominates at higher temperatures. The good agreement between the theory and our comprehensive data set gives confidence in using the QC-normalized CNT as a powerful tool to study neutral and ion-induced binary particle formation in atmospheric modeling.

International audience; We are currently extending the two-component nucleation parameterization for sulphuric acid and water in stratospheric conditions (Vehkamäki et al., 2002) for a larger validity range. One motivation for doing this was the need for nucleation parameterizations for the atmosphere of Venus. Both the clouds of Venus and aerosols found in the Earth’s stratosphere are mainly composed of sulphuric acid droplets, and sulfuric acid nucleation has a role also in tropospheric particle formation.

The South African savannah region is a complex environment of air pollution and natural emissions influenced by a strong seasonal cycle in biomass burning and strong precipitation. However, the scarcity of long-term observations means that the knowledge of controlling aerosol processes in this environment is limited. Here we use a recent dataset of 18 months of aerosol size distribution observations trying to understand the annual cycle of cloud condensation nuclei (CCN). Our observations show that the concentration of CCN-sized particles remains, in line with previous studies, high throughout the year with the highest concentrations during the dry winter and the lowest during the wet summer. During the wet season with reduced anthropogenic and biomass burning primary emissions, this pool of CCN is partly filled by boundary layer nucleation with subsequent growth. The enhanced importance of formation and growth during the wet season is addressed to increased biogenic activity together with enhanced free tropospheric removal decreasing the concentration of pre-existing CCN. During the dry season, while frequent new particle formation takes place, particle growth is reduced due to reduced condensing vapour concentrations. Thus in the dry season particles are not able to grow to sizes where they may act as CCN nearly as efficiently as during the wet season. The observations are compared to simulations by a global aerosol model GLOMAP. To our surprise, the global aerosol model utilized to explain the observations was not capable of re-producing the characteristics of particle formation and the annual CCN cycle, despite earlier good performance in predicting the particle concentrations in a number of diverse environments, including the South African savannah region. While the average yearly CCN concentrations of modelled CCN is close to observed concentrations, the characteristics of nucleation bursts and subsequent growth are not captured satisfactory by the model. Our sensitivity tests using different nucleation parameterizations and condensing organic vapour production rates show that neither of these is likely to explain the differences between observed and modelled nucleation and growth rates. A sensitivity study varying 28 modelling parameters indicates that the main uncertainties in the result are due to uncertainties in biomass burning emissions during the dry season, and anthropogenic sulphur emissions during the wet season, both in terms or emitted mass and particle sizes. The uncertainties appear to be mostly related to uncertainties in primary particle emissions, including the emissions variability not captured by monthly emission inventories. The results of this paper also highlights the fact that deficiencies in emissions estimates may result in deficiencies in particle production fluxes, while the end product such as modelled CCN concentration may be in line with observations http://www.atmospheric-chemistry-and-physics.net/ http://www.atmospheric-chemistry-and-physics.net/ http://www.atmos-chem-phys.net/13/issue4.html http://dx.doi.org/10.5194/acp-13-1957-2013

Seven patients with spastic neuromuscular disease and severe hindfoot valgus deformity were treated by subtalar arthrodesis. Arthrodesis was performed in both feet at the same operation and fixed on one side with a self-reinforced poly-L-lactide (SR-PLLA) screw, and with a standard AO screw on the other side. The functional status state was improved, and radiographic union of the arthrodesis occurred in all feet. The radiograph showed better solid fusion in five feet treated with PLLA screws, similar fusion in both sides in one patient, and one slower fusion in the side treated initially with a PLLA screw. Totally absorbable SR-PLLA screws appear to be firm enough for fixation of subtalar extraarticular arthrodesis in children.

In a series of 32 patients, the tibia was lengthened nine times and the femur 26 times. The lengthening was 4.1 cm in the tibia and 4.9 cm in the femur. The callotasis principle and atraumatic handling of the periosteum were considered important. The leg inequality was corrected appropriately, except in cases where the leg-length inequality was greater than 12 cm as a result of a progressive congenital deformity. Late femoral fractures occurred in six patients, but no tibial fractures were seen. One hip dislocation was seen after femoral lengthening, one talus deformation developed after the tibial lengthening, and one peroneal nerve entrapment was released operatively. One infection caused delayed bone union. Average follow-up time was 5.0 years.