Self-charging of identical grains in the absence of an external field.

We investigate the electrostatic charging of an agitated bed of identical grains using simulations, mathematical modeling, and experiments. We simulate charging with a discrete-element model including electrical multipoles and find that infinitesimally small initial charges can grow exponentially rapidly. We propose a mathematical Turing model that defines conditions for exponential charging to occur and provides insights into the mechanisms involved. Finally, we confirm the predicted exponential growth in experiments using vibrated grains under microgravity, and we describe novel predicted spatiotemporal states that merit further study.

Indoor radon, geogenic radon surrogates and geology - Investigations on their correlation.

The indoor radon concentration was measured in most houses in a couple of municipalities in Austria. At the same time the activity concentration of radium in soil, the soil gas radon concentration, the permeability of the ground and the ambient dose equivalent rate were also measured and the geological situations (geological units) were recorded too. From the indoor radon concentration and different house and living parameters a radon potential (Austrian radon potential) was derived which should represent the radon concentration in a standard room. Another radon potential (Neznal radon potential) was calculated from the soil gas radon concentration and the permeability. The aim of the investigation was to correlate all the different variables and to test if the use of surrogate data (e.g. geological information, ambient dose equivalent rate, etc.) can be used to judge the radon risk for an area without performing numerous indoor measurements.

Radon mapping strategies in Austria.

According to current European and international recommendations (e.g. by IAEA, WHO and European Union), countries shall identify high radon areas. In Austria, this task was initiated already in the early 1990s, which yielded the first Austrian Radon Potential Map. This map is still in use, updated with recent indoor radon data in 2012. The map is based on radon gas measurements in randomly selected dwellings, normalised to a standard situation. To meet the current (legal) requirements, uncertainties in the existing Austrian radon map should be reduced. A new indoor radon survey with a different sampling strategy was started, and possible mapping methods are studied and tested. In this paper, the methodology for the existing map as well as the planned strategies to improve this map is discussed.

The Austrian radon activities on the way to the national radon action plan.

Based on the new Euratom Basic Safety Standards (BSS), all EU member states will be obliged to design a strategy to address long-term risks from radon exposure, which is laid down in the 'national radon action plan'. In Austria, the National Radon Centre is responsible for the development of the action plan. This paper presents the current and planned radon protection activities on the way to establish the radon action plan--like the national radon database, the definition of radon risk areas by improving the existing radon map, as well as strategies and activities to increase the radon awareness of the public and decision-makers and to involve the building sector. The impact of and the need for actions caused by the BSS requirements on the Austrian radon legislation, strategy and programme are discussed.

Post-Earthquake Injuries Treated at a Field Hospital ù Haiti, 2010

La "University of Miami Global Institute/Project Medishare" (UMGI/PM) a créé le premier hôpital de campagne à Port-au-Prince, en Haïti, après le séisme. Afin de caractériser les blessures et les interventions chirurgicales effectuées par l'UMGI/PM et d'évaluer les besoins spéciaux médicaux, chirurgicaux et de réadaptation, l'UMGI/PM et le "Centers for Disease Control and Prevention" (CDC) mènent une analyse rétrospective de tous les dossiers médicaux de malades disponibles pour la période du 13 janvier au 28 mai 2010. Le premier article de cette revue décrit les résultats de cette analyse et présente les données quantitatives obtenues.

[Uncommon condition of the upper gastrointestinal tract: double pylorus]. / Seltene Befunde am oberen Gastrointestinaltrakt: Der Doppelpylorus.

Double pylorus and gastroduodenal fistula are uncommon conditions that are either congenital or acquired. Acquired double pylorus in most cases resulted from a penetrating peptic ulcer creating a fistula between the duodenal bulb and the prepyloric antrum. The diagnosis is usually made by endoscopy. Surgical intervention should be only considered for patients with refractory symptoms, recurrent ulcers and other complications. We report the case of a 85-year-old man with an acquired duodenal-antral fistula resulting from a retrograde penetration of an ulcus duodeni and simulating a double pylorus.

Surgery in adult onset tethered cord syndrome (ATCS): review of literature on occasion of an exceptional case.

Tethered cord syndrome, usually discovered in childhood, is a developmental abnormality impairing the longitudinal movement of the spinal cord that can be combined with various forms of spinal dysraphism. Adult onset tethered cord syndrome (ATCS) seems not as rare as once thought, however, low susceptibility in adulthood commonly leads to a delay in diagnosis and therapy. We conducted a meticulous literature research to evaluate the clinical presentation, associated malformations, prognostic factors, as well as the benefits and risks of surgical treatment in ATCS patients. The age of patients at onset of symptoms ranged from 18 to 76 years with a mean of 36.5 years, including 184 males and 202 females. In contrast to the pediatric clientele, pain is the predominant symptom in adults, and elicitating mechanisms like trauma, excessive physical training, or degenerative spinal canal stenosis are reported more often. Surgical untethering aims the restoration of craniocaudal mobility of the spinal cord in order to prevent the further progression of symptoms, to restore neurological function, and to improve pain. In our evaluation of literature, pain was the most responsive symptom after surgical untethering (307 of 368 patients). Sensory and motor symptoms also seem to benefit from the surgery, especially if less than 6 months standing and mild. Improvement could be achieved in 43% (144 of 335 patients) for sensory deficits and 58.6% (191 of 326 patients) for motor deficits. Sphincter troubles are less responsive; they show an improvement in 45.6% (141 of 309 patients). Factors reported to be associated with the postoperative deterioration and/or bad outcome are the split cord malformation, lipomyelomeningocele, previous surgery, rapid motor function worsening experienced shortly before the operation, and long delay in diagnosis. The rate of secondary decline and retethering could not be established in our literature research. We report on an additional case of ATCS with the late onset of symptoms at the age of 49; she underwent surgical untethering with neuronavigational guidance. Performing neuronavigational guidance on the basis of multimodal images (computed tomography and magnetic resonance imaging fused with the intraoperative biplanar X-ray) in our patient showed substantial benefit in the surgical orientation within a complex skeletal and neuronal anomaly.

Surgical management of an ACM aneurysm eight years after coiling.

The authors present a case report on rebleeding of a medial cerebral aneurysm (MCA) eight years after complete endovascular coiling. The primarily successfully coiled MCA aneurysm showed a local regrowth which, however, was not the source of the rebleeding. The angiogram demonstrated no evidence of contrast filling of the coiled segment, but according to intraoperative findings (haematoma location, displacement of coils, evident place of rupture) there is no doubt that the coiled segment of the aneurysm was responsible for the haemorrhage.

Cavernous haemangiomas of the anterior visual pathways. Short review on occasion of an exceptional case.

The anterior optic pathways are rarely affected by vascular malformations. In a meticulous literature review, 42 published cases of patients with vascular malformations within optic nerves, chiasma and/or optic tract were found, 30 of them being diagnosed as cavernous haemangiomas. All of them suffered from visual disturbances; in 38.1% previous symptoms had occurred. Surgical treatment resulted in major improvement in most patients. We include a further patient with a cavernous haemangioma of the optic chiasma and left optic tract who presented with an acute defect of the right visual field and severe retro-orbital pain. We succeeded in total excision of the malformation via a neuronavigationally guided approach. In the postoperative course, vision of our patient improved immediately and was found to be completely normal three months after the surgical intervention. Considering our patient and the published cases in the literature, we are of the opinion that microsurgical excision is a safe and efficient treatment for these rare pathologies.

Microneurosurgical water probe.

When constructing the micro-neurosurgical water ball probe, the authors have simply combined the properties of a ball probe with an irrigational function and the supportive role of water current to form a new irrigating ball dissector. The micro-instrument has an outlet mechanism with which the surgeon can regulate the flow of physiological solution into the operational field. Its point has the properties of a ball probe, and the overall bayonet shape facilitates surgical interventions in deep tissues under microscopic control. The water probe therefore enables the surgeon to perform precise mechanical preparation supported by a regulated current of water and a targeted irrigation in the operational field. The physiological solution in the pressure infusion cuff is under minimal pressure and directly connected to the probe. Due to the fact that one device can be used for various purposes the water ball probe represents an advantageous alternative to conventional micro-neurosurgical preparation.

Acquired torticollis due to Grisel's syndrome: case report and follow-up of non-traumatic atlantoaxial rotatory subluxation.

Non-traumatic atlantoaxial rotatory subluxation is an uncommon entity, with inconsistent presentations. It is also known as Grisel's syndrome (GS), and most commonly follows infectious processes of the upper respiratory tract. A case is described of a non-traumatic rotatory atlantoaxial dislocation in a three-year-old boy. The patient presented with acute torticollis one week after mild upper respiratory infection. Neurological evaluation and lumbar punction were normal. After five days of intractable pain and non-reducible rotational tilt of the head to the left, CT and MR imaging were performed and showed atlantoaxial rotatory subluxation. In addition, MRI demonstrated middle ear and mastoid inflammation. Tilt reduction could be obtained through gentle skull traction under sedation and relaxation for 3 days. Antibiotic treatment was performed. The patient was then placed in a Minerva cast jacket. After seven weeks of immobilization, CT demonstrated regular atlantoaxial alignment. Follow-up after 5.5 years showed the boy neurologically intact and free of clinical complaints. Dynamic cervical radiographs confirmed that the atlantoaxial joints were stable.

[Collisiontumour composed of glioblastoma and meningioma-a case report]. / Kollisionstumor des GehirnsTumorkomponenten aus einem Glioblastom und einem Meningeom.

A 51 year old caucasian male presented with headache, facial nerve paresis and continuing contraction of the visual field. CT scan revealed a singular intracerebral contrast enhancing lesion in the left frontal lobe. Intraoperatively the tumour was well demarcated. Frozen sections showed a high grade glioma. Paraffin sections revealed, in addition to the gliomatous component, some sharply demarcated nests of meningothelial cells. Immunohistochemistry with glial fibrillary acidic protein and epithelial membrane antigen confirmed a collision tumour consisting of a glioblastoma WHO-grade IV and a meningothelial meningioma WHO-grade I. The coincidence of these two different tumours at the same time and the same location leads us to the speculation, that the collision tumour might have been caused by malignant transformation of a reactive astrogliosis surrounding the meningioma.

[Influence of 2-aryl-3-halogen/3-hydroxy-1,4-naphthoquinones with salicylic and cinnamic acid partial structures on the arachidonic acid cascade]. / Beeinflussung der Arachidonsäurekaskade durch 2-Aryl-3-halogen/3-hydroxy-1,4-naphthochinone mit Salicyl- und Zimtsäure-Partialstruktur Untersuchungen an 1,4-Naphthochinonen, 29. Mitt.

Searching for more potent 5-lipoxygenase (LO) inhibitors one tert-butyl group of the selective 5-LO-inhibitor 2-(3,5-di-tert-butyl-4-hydroxyphenyl)-3-hydroxy-1,4-naphthoquinone (1) was substituted by polar functions (-CHO, -COOH, -CH=CH-COOR, -CH2-CH2-COOR). At the same time the 5-LO selectivity of the new compounds within the arachidonic acid cascade was investigated. For this 12-LO- and COX-1-assays with activated human platelets were used. Screening the test compounds new selective 5-LO-inhibitors (4, 9 and 16) and a COX-1-inhibitor (10) as well as dual 5-LO/COX-1- (23) and 12-LO/COX-1- (12) inhibiting compounds were found. Obviously in this class of compounds 5-LO and 12-LO inhibition are mutually excluded for a structural reason. In addition to the well known 3-chloro- (19) and 3-bromo- (20) analogues of 1 the 3-fluoro- (22), 3-iodo- (23) and the 3-carbonitrile- (24) derivatives were synthesized. All 3-halogen compounds, except 23 and the nitrile, are potent non selective inhibitors of all three enzymes. Causative for this unselectivity is the inhibition of the arachidonic acid release by inhibition of the cytosolic phospholipase A2 (cPLA2) with the exception of 24.

Distinct supratentorial lesions mimicking cerebral gliomas.

BACKGROUND: Various supratentorial pathological conditions can mimic neoplastic cerebral lesions clinically as well as radiologically. Analysis of the neuroradiological findings, the clinical history, laboratory and other paraclinical data mostly help to narrow down the diagnosis of cerebral pathologies. Sometimes, however, histopathological analysis of the operative specimen after surgery reveals unexpected findings. PATIENTS AND FINDINGS: In a series of 197 operative procedures performed for glioma surgery between August 2000 and August 2002 we found six distinct cases mimicking supratentorial tumours. Clinicoradiological findings had suggested a neoplastic gliomatous process in all cases. But histopathological examination revealed that in reality one patient had been affected by a stroke, two by hypertensive encephalopathy, and one by radiation necrosis; multiple sclerosis was the underlying pathology in two patients. INTERPRETATION: Conditions which show features similar to those of neoplastic cerebral lesions require advanced magnetic resonance imaging (MRI). The benefit of such sophisticated imaging in relation to the costs is an important issue in this context. Further research in the field of modern image modalities is necessary to evaluate these noninvasive techniques for specification of intracerebral lesions.

[Inhibition of the arachidonic acid cascade by aza-2-aryl-1,4-naphthoquinone derivatives]. / Hemmung der Arachidonsäurekaskade durch Aza-2-aryl-1 ,4-naphthochinon- Derivate.

Inhibition of the arachidonic acid cascade by aza-2-aryl-1,4-naphthoquinone derivatives To find more potent 5-lipoxygenase(LO)-inhibitors than the up to now studied 2-(3,5-di-tert-butyl-4-hydroxyphenyl)-3-hydroxy-1,4-naphthoquinone derivatives the analogous aza-1,4-naphthoquinones 14, 15, 16/17 as well as the 3-bromo precursors 7, 8, 9/10 and 11 were synthesized. The naphtho[2,1-b][1,4]thiazin derivative 21 was included in this investigation as a quinone imine. Beside 5-LO inhibition the influence on 12-LO, COX-1 and cPLA2 was determined to investigate the selectivity of the compounds within the arachidonic acid cascade. To test the biochemical properties human granulocytes (5-LO) and human platelets (12-LO/COX-1 and cPLA2) were used. All 3-bromo compounds inhibit completely the arachidonic acid cascade by blocking the cPLA2. The 3-methoxy derivatives of the quinoline quinones 12 and 13 and the 3-hydroxyisoquinoline mixture 16/17 show 5-LO selectivity. 13 inhibits 5-LO selectively, 12 is a dual 5-LO/COX-1-inhibitor and 16/17 are dual 12-LO/COX-1-inhibitors. To verify the hypothesis that the hydroxylated 2-aryl-1,4-benzoquinone structure is the pharmacophore for 5-LO-inhibition within the class of 2-aryl-1,4-naphtho- and -aza-naphthoquinones the 2-(3,5-di-tert-butyl-4-hydroxyphenyl)-1,4-benzoquinones 24-28 were synthesized. It was shown that the 5-methoxy and 5-hydroxy compounds 24 and 27 are highly selective and potent 5-LO-inhibitors.

[Methylated 2-aryl-1,4-naphtoquinone derivatives with diminished antioxidative activity]. / Methylierte 2-Aryl-1,4-naphthochinonderivate, 5-Lipoxygenase-Inhibitorenmit reduzierter antioxidativer Aktivität.Untersuchungen an 1,4-Naphthochinonen, 28. Mitt.

Methylated 2-aryl-1,4-naphtoquinone derivatives with diminished antioxidative activity 2-(3,5-Di-tert-butyl-4-hydroxyphenyl)-3-hydroxy-1,4-naphthoquinone (1) is a selective 5-lipoxygenase (5-LOX) inhibitor possessing high antioxidative activity (AOA). In order to study the question if this activity corresponds to the mechanism of the 5-LOX inhibition (redox type 5-LOX inhibitor) the analogues 57-66 and their 3-methoxy derivatives 47-56 of the reference compound 1 were synthezised. These compounds are mono- and dimethylated within the benzoid molecular moiety which were tested for their 5-LOX inhibiting activity using human granulocytes and for their AOA by a chemiluminometric method. The synthesis of the test compounds runs in the following manner: Diels-Alder reaction of 1,4-benzoquinone (2) with the buta-1,3-dienes 3-8, bromination of the 1,4-naphthoquinones 9-14, arylation with 2,6-di-tert-butylphenol and substitution of bromine of the aryl-bromonaphthoquinones 33-46 by methoxy and hydroxy functions. A key step is the cc separation of the regioisomeric mixtures 25/26-31/32. The most potent 5-LOX inhibitors (IC50 = 1-3 microM) possess methylfunctions in 5-/8-position and show markedly diminished AOA compared with 1. 5-LOX inhibition and AOA in this class of compounds hence are not positively correlated.

Recurrent cryptic vascular malformation associated with a developmental venous anomaly.

Abnormal venous drainage patterns, such as developmental venous anomalies (DVAs), are frequent findings neighbouring cryptic vascular malformations (CVMs). Although the clinical relevance of DVAs remains controversial, increasing attention has been focused on the possible importance of venous outflow disturbance and venous hypertension in DVAs for the development of CVMs. We present the case of a 32-year-old man with dysphasic seizures symptomatic for recurrence and rebleeding of a CVM of the left angulare gyrus, which drained entirely into a large DVA. A cavernoma had been surgically removed 1 year before, while the associated DVA had been left in place. In the following second surgical procedure, the new malformation, which was histologically verified as arteriovenous angioma (AVM), was removed and the DVA was occluded for the length of the angioma. Postoperative course of the patient was unremarkable, the patient is seizure free and neurologically intact. This first report of such a sequence of events raises important questions regarding the association of various vascular malformations, regarding transitional and hybrid forms, as well as the role of anomalous venous drainage in their pathophysiology and probably in their development. Our case and selected cases in literature suggest that venous hypertension in a DVA might not be just a coincidential finding, but sometimes can induce or influence the development and recurrence of associated vascular lesions. The developmental interrelationship, the potential mechanisms for this association and the implications of similar cases reported in pertinent literature are discussed.

Aerodynamical sticking of dust aggregates.

We present results of collision experiments of a dense beam of aggregated 1.2 microm SiO2 particles entrained in a gas flow with metal targets of different widths. Depending on the target width (d=25.4, 50.8, and 127 microm) and the ambient gas pressure (p=0.5-2.0 mbar), the growth of a dust pile on the target begins at a threshold impact speed (v(imp)=6-12.5 m/s). These threshold velocities for sticking exceed the limit for total disruption of aggregates by more than a factor of 5-10 for the given parameters. We found that a significant number of fragments (single particles) from the collisions had a very low coefficient of restitution c(r) at least down to c(r)<0.05 that is much lower than the value c(r)>0.5 that one of the single solid micron-sized particles would have while impinging a rigid target. Due to the drag of the gas flow these slow fragments are forced back to the target a second time resulting in sticking that eventually leads to the formation of the dust pile in spite of the high impact velocities. Together, the fragmentation, the low coefficients of restitution of a significant number of fragments, and the gas flow provide an efficient growth mechanism for bodies that would otherwise lose mass. We consider this an important mechanism for the formation of planetesimals in the solar nebula.