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.

Interactions of inhibitors of the lipoxygenase and cyclooxygenase pathways with a supplementary binding site on soybean lipoxygenase.

The oxygenation of [1-14C]-arachidonic acid by a soluble soybean lipoxygenase (E.C.1.13.11.12) preparation was determined in the presence of various cyclo-oxygenase and lipoxygenase inhibitors. The results showed that several non-inhibitory compounds drastically blunted the inhibitory potency of potent lipoxygenase inhibitors. Studies on the combined effects of a variety of structurally unrelated inhibitors of lipoxygenase, cyclo-oxygenase or both oxygenation pathways provided strong evidence for the existence of a supplementary binding site on soybean lipoxygenase which reduces the effective interactions of inhibitors with the catalytic site. Thus several cyclo-oxygenase inhibitors (which do not inhibit at the lipoxygenase catalytic site), as well as low concentrations of lipoxygenase inhibitors, interact with this putative supplementary site and blunt the inhibitory efficacy of potent lipoxygenase inhibitors. Although the degree of interaction with the catalytic site determines the absolute potency of inhibitors, the additional interaction at the putative supplementary binding site is also obligatory for inhibitory potency. In this new multiple-site model the potent lipoxygenase inhibitors (e.g. acetone phenylhydrazone, phenidone) possess high affinities for both sites, whereas weak inhibitors and certain cyclo-oxygenase inhibitors (e.g. benoxaprofen, phenylbutazone, indomethacin) interact predominantly with the supplementary site on the lipoxygenase but lack affinity for the catalytic site.

Substrates for arachidonic acid co-oxidation with peroxidase/hydrogen peroxide. Further evidence for radical intermediates.

We tested the ability of a wide variety of organic compounds, including benzene and phenol derivatives, aromatic amines, pyrazoline derivatives and other non-steroidal anti-inflammatory drugs, to act as cosubstrates during the horseradish peroxidase/hydrogen peroxide-mediated oxygenation of arachidonic acid. Structural requirements for drug activation in our system proved to be an aromatic system and ring substitution by an easily oxidizable group. Complementary substituents modified drug activation. Among the phenol derivatives and aromatic amines we found the meta-substituted compounds to be significantly more effective than their ortho- and para-substituted analogues, indicating the involvement of radical intermediates in this type of reaction. The radical from 1-phenyl 3-methyl 2-pyrazolone(5) was detected by electron paramagnetic resonance spectroscopy. Kinetic studies on this radical were in good accordance with time-dependent measurement of arachidonic acid oxygenation.

A structure-activity study on the influence of phenolic compounds and bioflavonoids on rat renal prostaglandin synthetase.

The stimulating or inhibiting influences of 33 phenolic compounds on the prostaglandin synthetase of rat renal medulla were tested. Dihydroxyphenylcarbonic acids clearly proved to be activators of the prostaglandin synthetase. Dimethoxyphenylcarbonic acids were ineffective. Aminoethylphenols as well as p-substituted monohydroxybenzenes with a carbonic acid side chain were clear stimulators in contrast to their alkyl derivatives which are pronounced inhibitors. Among the tested bioflavonoids (+)-cyanidanol-3 and morin were inhibitors of the prostaglandin synthesis. Flavonoids with polar substitution in 3,5,7-position such as rutin on the other hand showed activating properties.

Advanced surgical approach for selective amygdalohippocampectomy through neuronavigation.

OBJECTIVE: Selective removal of the mesiobasal temporal structures through the transsylvian approach was introduced by Yasargil and Wieser in 1982. This alternative to standard temporal lobectomy provides excellent outcomes for seizure control. Basic actions in the transsylvian fissure exposure mainly serve to orient the surgeon, and they carry the risk of vasospasm and vessel damage. The aim of our study was to reduce landmark-guided surgery steps through neuronavigation. METHODS: During a 14-month period, 16 selective amygdalohippocampectomies were performed with the aid of the SMN (Carl Zeiss, Inc., Thornwood, NY) or StealthStation (Sofamor Danek, Memphis, TN) optically guided systems. We added safety procedures to the operation (including intraoperative rereferencing, obtaining additional bony reference points before craniotomy, performing a small craniotomy and making an accurate dural incision, and using contrast medium for vessel visualization) to develop a method that relies on navigational systems without further orientation by anatomic landmarks. RESULTS: Originally, performing an amygdalohippocampectomy required exposing the sylvian fissure from the carotid bifurcation to 2 cm beyond the middle cerebral artery bifurcation, which exposed one-third of the insula. By determining the entry point at the limen insulae and the target at the tip of the temporal horn, the mandatory extent of the opening to the sylvian fissure can be projected. Therefore, the exposure of the fissure can be limited to exactly the extent required for the transventricular approach through the uncinate fasciculus. CONCLUSION: Computer-assisted surgery is an effective tool in eliminating the exposure of anatomic landmarks in selective amygdalohippocampectomy. This modification combines the precision of targeting with minimal cortical and vessel traumatization.

School-based identification of asthma in a low-income population.

The increase in the prevalence, morbidity, and mortality of asthma among children over the last decade has been well documented, especially among low-income minority children. Hypotheses for the increases in morbidity and mortality include limited access to primary care services and the failure to recognize the presence and severity of asthma. The University of Miami Pediatric Mobile Clinic (Mobile Clinic) Asthma Intervention Program is designed to identify underserved asthmatic children at school and offer them culturally sensitive care. Nine elementary schools with low income, predominantly Hispanic and African-American populations regularly served by the Mobile Clinic, were chosen for study participation. All 5,800 students who were enrolled in kindergarten through third grade were given letters at the time of registration by their homeroom teachers about the asthma program. Caretakers who returned the questionnaire and reported that the student had asthma symptoms were invited to have the student undergo a medical evaluation in the Mobile Clinic. Over a 2-year period, caretakers of 423 students (7.3% of all students) expressed an interest in further evaluating their child's respiratory health. Of these, we enrolled and evaluated 154 in the Mobile Clinic's Asthma Intervention Program. The Mobile Clinic physicians identified 145 of the enrollees as having asthma. These results indicate that in elementary schools serving predominantly low-income minority populations, a large fraction of the asthmatic population (estimated prevalence, 6-10%) can be identified by a school-based letter. Further, in a subset of asthmatic students (children of interested caretakers), there is good agreement between caretaker responses and physician diagnosis of asthma. Since school attendance is mandatory, school-based methods may be an effective method for identifying low-income children with asthma.

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.

[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.

[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.

[2-(3-Halogen-4-hydroxyphenyl)-1,4-napthoquinone derivatives from 2-(3,5-di-tert-butyl-4-hydroxyphenyl)-analogs, potent 5-lipoxygenase inhibitors. 27. 1,4-Naphthoquinones]. / 2-(3-Halogen-4-hydroxyphenyl)-1,4-naphthochinon-Derivate aus 2-(3,5-Di-tert-butyl-4-hydroxyphenyl)-Analoga, potente 5-Lipoxygenase-Inhibitoren. Untersuchungen an 1,4-Naphthochinonen, 27. Mitt.

A new simple and fast method for the synthesis of halogenated hydroxyphenyl naphthoquinones as potential 5-lipoxygenase (LOX) inhibitors is presented. While the aryl naphthoquinone 1, a potent 5-LOX inhibitor, with AlCl3 is debutylated to 2a and 2b, the oxidized cyclohexadienylidene derivative 3 reacts comparably by concomitant halogenation to 4a and with AlBr3 to 4b, respectively. As products of a side reaction of 6 with TiCl4 and BBr3 the tetracyclic benzo[b]naphthol[2,1-d]furan derivatives 8a and 8b are isolated. Selected compounds are investigated for 5-lipoxygenase inhibiting and antioxidative properties. There is a clear-cut correlation of both qualities in those compounds with a 3-OH function and with two, one or without any tert-butyl group at the phenyl moiety. In contrast the quinone 6 (3-Cl) and the dibenzofuran 8a are powerful 5-LOX inhibitors with only low antioxidative activity.

[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.

[Partially hydrogenated aryl-1,2/1,4-anthraquinone derivatives, 5-lipoxygenase inhibitors with arotinoid structure]. / Partiell hydrierte Aryl-1,2/1,4-anthrachinon-Derivate, 5-Lipoxygenase-Inhibitoren mit Arotinoid-Struktur.

The combination of 5-LOX inhibition and retinoid activity in one molecule could be an interesting pharmacological tool to influence psoriasis. Thus we synthesized compounds with arotinoid structure by anellation of the 5-LOX inhibitors 1 and 2 with 1,1,4,4-tetramethylcyclohexane. A key step was the CuCl-MeCN-O2 oxidation of tetrahydroanthracenol 13 to the corresponding 1,2-anthraquinone 14 which could be converted to the analogous 2-hydroxy-1,4-anthraquinone 19 by Thiele-Winter reaction followed by oxidation. The halogenated quinones 9 and 21 were arylated with 2,6-di-tertbutylphenol and demethylated or hydrolyzed to the target compounds 3 and 4 which were tested in comparison with the non-anellated 5-LOX inhibitors 1 and 2 for LOX inhibition in activated human granulocytes and for antioxidative activity by the method of Popov with the chemiluminometer Photochem. The results are discussed in relation to the corresponding logP values. The 1,2-quinones 1 and 3 are more potent 5-LOX inhibitors than their 1,4-analogues 2 and 4, the tetrahydroanthraquinon derivatives 3 and 4 are less potent than the naphthoquinones 1 and 2. All compounds are devoid of any activity in cell differentiation as compared to retinoic acid as indicated by the NBT test with HL-60 leukemia cells.

[Traumatic injury of the internal carotid artery in the extracranial segment. Description of a severe late complication]. / Traumatische Schädigung der Arteria carotis interna im extrakraniellen Bereich. Beschreibung einer schweren Spätkomplikation.

Blunt traumatic injury to the extracranial internal carotid artery may lead to a dissection with resultant stenosis, occlusion, or a dissecting aneurysm. Delayed clinical presentation weeks, months, and even years after the injury is rare, but has important diagnostic, therapeutic and forensic implications. In the current era, where computed tomography is replacing angiography as the main diagnostic procedure, it is extremely important to keep this diagnosis in mind. We report the case of a 31-years-old male patient, who did well after a motorcycle accident with head and neck injury for six years. Since then he only showed left-side Horner's syndrome, which unfortunately was ignored. In 1993 the patient developed occlusion of central retinal artery, and after a therapy with streptokinase he presented with right-side palsy and complete aphasia. CT-scan revealed a large edematous infarction in the middle cerebral artery territory. Transfemoral digital subtraction angiography however demonstrated a dissecting aneurysm of the left extracranial internal carotid artery as the source of intracranial embolization. Severe sequelae of this kind can only be warded of by early diagnosis and proper surgical therapy of vascular injury. Therefore even minimal symptoms suggesting the possibility of a traumatic injury to the carotid artery are recommending timely angiographic investigation.

[Stereotaxic biopsy of brain tumors]. / Streotaktická biopsia mozgových nádorov.

The work re-evaluates the meaning of stereotactic bioptic examination in 50 neurosurgical patients. Bioptic material gained for histologic purposes does not secure always the achievement of the correct histologic diagnosis. The authors critically reevaluate the possibilities of this diagnostic method. They do not consider as adequate to claim multiple expansive processes to be inoperable, respectively as being refractory towards therapy, when the histologic conclusion is lacking. In cases of inconsistency in histologic conclusions from two neuropathologists the further fate of the patient is conditioned by the neuropathologist's stand-point, but also by the clinical experience of the neurosurgeon who overtakes the final responsibility for the patient's further fate. Recently available methods (CT,MR, spectrography) are diagnostically not so precise as to be able to manage without stereotactic biopsy. (Tab. 3, Fig. 5, Ref. 10.).

[The role of the neurosurgeon in histopathologic diagnosis]. / Moznosti a úloha neurochirurga v histopatologickej diagnostike.

Neurosurgical practice has proved that the establishment of a correct neurohistopathologic diagnosis is sometimes difficult. Inconsistency of diagnoses resulting from unbiased examinations of several neuropathologists is not uncommon. The authors-neurosurgeons-have performed 300 fast neurohistopathologic examinations by means of smear technique. Correct diagnosis was stated in more than 90% of cases. Bioptic examination may represent a contribution in cases where postoperative irradiation is indicated, namely under diagnostically controversial circumstances. The authors re-evaluate the possibilities of utilization of smear technique for the purpose of histopathologic diagnostics performed directly by neurosurgeons. (Tab. 7, Ref. 5.).

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.