Atmospheric new-particle formation affects climate and is one of the least understood atmospheric aerosol processes. The complexity and variability of the atmosphere has hindered elucidation of the ...fundamental mechanism of new-particle formation from gaseous precursors. We show, in experiments performed with the CLOUD (Cosmics Leaving Outdoor Droplets) chamber at CERN, that sulfuric acid and oxidized organic vapors at atmospheric concentrations reproduce particle nucleation rates observed in the lower atmosphere. The experiments reveal a nucleation mechanism involving the formation of clusters containing sulfuric acid and oxidized organic molecules from the very first step. Inclusion of this mechanism in a global aerosol model yields a photochemically and biologically driven seasonal cycle of particle concentrations in the continental boundary layer, in good agreement with observations.
The growth of freshly formed aerosol particles can be the bottleneck in their survival to cloud condensation nuclei. It is therefore crucial to understand how particles grow in the atmosphere. ...Insufficient experimental data has impeded a profound understanding of nano-particle growth under atmospheric conditions. Here we study nano-particle growth in the CLOUD (Cosmics Leaving OUtdoors Droplets) chamber, starting from the formation of molecular clusters. We present measured growth rates at sub-3 nm sizes with different atmospherically relevant concentrations of sulphuric acid, water, ammonia and dimethylamine. We find that atmospheric ions and small acid-base clusters, which are not generally accounted for in the measurement of sulphuric acid vapour, can participate in the growth process, leading to enhanced growth rates. The availability of compounds capable of stabilizing sulphuric acid clusters governs the magnitude of these effects and thus the exact growth mechanism. We bring these observations into a coherent framework and discuss their significance in the atmosphere.
A chronic illness, such as cancer, causes permanent changes in a person’s way of life and their way of adapting to changes. The purpose of this study was to describe the coping strategies and ...resources of adolescents and young adults with cancer. The data were collected by interviewing adolescents and young adults aged 16–22 (n = 14) who had had cancer for more than 2 months and who came to a university hospital for treatment or control check ups. The interview material was analysed by content analysis. Emotion‐focused, appraisal‐focused and problem‐focused coping strategies were used. The major coping strategies were social support, belief in recovery and getting back to normal life as soon as possible. The subjects discussed with health care providers their disease, its treatment and how they could cope with everyday life as well as their energy and will‐power to cope. The family was the most important source of emotional support. Also, gaining knowledge about cancer and its treatment was a good coping strategy. Moreover, a positive life attitude, belief in one’s own resources, belief in God, earlier life experiences and willingness to fight against the disease were resources for coping with cancer.
Background: Incidence of newly diagnosed HIV infections among injecting drug users (IDUs) in Helsinki rose from 0 per 100 000 inhabitants in 1997 to 2.9 in 1998 and to 11.1 in 1999. Thereafter ...incidence declined to 2.1 in 2003. Methods: Data were collected from interviews with HIV-positive IDUs who attended the University Hospital in Helsinki from 1998 until 2003. We studied the sociodemographic profile and spatial distribution of IDUs who were diagnosed in the beginning of the outbreak and those diagnosed later. The indicator for the spatial differentiation within the metropolitan area is % employed males aged 25–64. Results: The outbreak occurred among a marginalized population of IDUs characterized by a long history of injecting drug use (10.7 years), mean age 32 years, homelessness (66.3%), history of imprisonment (74.7%) and psychiatric hospital care (40.6%). Compared with 98 early cases diagnosed during the first 2 years until 2000, 47 recent cases diagnosed after 2001 were 4 years older, and as marginalized. Except for the city centre, both early and recent cases had been living or using drugs in the same deprived neighbourhoods with the highest unemployment rates. Up to 40% of cases in the two big geographical clusters did not have contact with the city centre, where the needle exchange services were available. Conclusions: The Finnish HIV outbreak is restricted socially to a very marginalized IDU population, and spatially to local pockets of poverty. In low prevalence countries, prevention programs should be targeted early at high-risk areas and populations.
To evaluate results of root canal treatment in dogs.
Retrospective study.
127 tooth roots in 64 dogs.
Radiographs obtained before surgery, immediately after surgery, and during follow-up examinations ...after surgery were evaluated by 2 individuals. Treatment was considered successful if the periodontal ligament space was normal and possible preoperative root resorption, if present, had ceased. Treatment was considered to show no evidence of failure if possible preoperative root resorption had ceased but a preexisting periapical lesion had remained the same or only decreased in size and not complete resolved. Treatment was considered to have failed if a periapical lesion or root resorption developed subsequent to endodontic treatment, if a preexisting periapical lesion had increased in size, or if possible preoperative root resorption appeared to continue after endodontic treatment.
Follow-up time ranged from 1 to 60 months (mean, 13 months). Treatment was classified as successful for 87 (69%) roots, as showing no evidence of failure for 33 (26%) roots, and as having failed for 7 (6%) roots. The success rate was lower for canine teeth than for maxillary fourth premolar teeth. Roots with a preexisting periapical lucency or preexisting root resorption had lower success rates. The use of intracanal medication and the method and quality of obturation were not associated with outcome.
Results suggest that root canal treatment offers a viable option for salvage of periodontally sound but endodontically diseased teeth in dogs.
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