Size-dependent influence of NOx on the growth rates of organic aerosol particles.

Atmospheric new-particle formation (NPF) affects climate by contributing to a large fraction of the cloud condensation nuclei (CCN). Highly oxygenated organic molecules (HOMs) drive the early particle growth and therefore substantially influence the survival of newly formed particles to CCN. Nitrogen oxide (NOx) is known to suppress the NPF driven by HOMs, but the underlying mechanism remains largely unclear. Here, we examine the response of particle growth to the changes of HOM formation caused by NOx. We show that NOx suppresses particle growth in general, but the suppression is rather nonuniform and size dependent, which can be quantitatively explained by the shifted HOM volatility after adding NOx. By illustrating how NOx affects the early growth of new particles, a critical step of CCN formation, our results help provide a refined assessment of the potential climatic effects caused by the diverse changes of NOx level in forest regions around the globe.

[Pelvic ring fractures in the elderly. Underestimated osteoporotic fracture]. / Beckenringfrakturen im Alter. Die unterschätzte osteoporotische Fraktur.

The incidence of pelvic fractures at 0.3-8% is low compared to all fractures. Nevertheless, the number of pelvic fractures in the elderly is increasing. Due to the increased age of the patient differences in trauma mechanism, fracture pattern and therapy occur. Most pelvic fractures in the elderly are caused by low-energy trauma. This makes it difficult to find the right diagnosis especially in insufficiency fracture of the pelvis. The time until the right treatment is started is prolonged significantly. Elderly patients who suffer from a high-energy fracture have a significantly higher risk of haemorrhage. At the same time emergency stabilisation of the pelvis using a C-clamp is dangerous due to the special fracture morphology with transiliac instabilities and the combination with osteoporosis. Low-energy trauma leads to simple fractures of the pubis, which often can be treated without operation. In these cases fractures of the dorsal pelvic ring need to be excluded using CT scan. Fracture of the dorsal part of the pelvic ring such as insufficiency fractures of the sacrum should be stabilized by 3D-guided percutaneous iliosacral screw fixation to reduce pain and allow early mobilisation.

[3D navigated osteosynthesis of calcaneal fractures. Open and minimally invasive techniques]. / 3D-navigierte Fersenbeinosteosynthese: Offene und minimal-invasive Technik.

BACKGROUND: It is hypothesized that misplacement of sustentacular screws during osteosynthesis of intraarticular calcaneal fractures can be reduced with the help of navigation. A method for three-dimensional (3D) navigated placement of sustentacular screws for treating intraarticular calcaneal fractures is presented and evaluated. MATERIAL AND METHODS: 11 consecutive patients with 15 intraarticular calcaneal fractures were treated using 3D navigation. In 12 cases osteosynthesis was done through an extended lateral approach; in three cases, it was achieved through a minimally invasive percutaneous approach. For verification and documentation of the placed screws, a second 3D scan was performed. RESULTS: A total of 20 screws were placed using 3D navigation. None of the navigated screws was misplaced. Extra operating time due to navigation averaged 11.9 minutes (+/-2.2 min). CONCLUSION: Through a combination of intraoperative 3D imaging and navigation, placement of sustentacular screws is possible and can yield precise and reliable results. Especially in minimally invasive treatment, a high quality of osteosynthesis can be achieved.

[Persistent dysphagia and mechanical glottic paralysis. Complications of a ventral fracture spondylodesis with Forestier's disease]. / Persistierende Dysphagie und mechanische Glottisparese: Komplikation einer ventralen Frakturspondylodese bei Morbus Forestier.

Persistent dysphagia after ventral instrumentation of a patient with a cervical spine fracture and diffuse idiopathic skeletal hyperostosis (DISH, or Forestier's disease) is a rare but dramatic complication. In this case report some pathogenetic factors are discussed. Accurate resection of the spondylophytes should be considered to avoid a ventral protrusion of the plate.