Stellenwert der kontrastmittelunterstützten Sonographie (CEUS) im Vergleich zur konventionellen B-Bild Sonographie und der Referenzprozedur (KM-CT) in der Abgrenzung eines zentralen Lungentumors von einer nachgeschalteten Atelektase: eine retrospektive Studie

Ziel: Die Computertomographie (CT) mit Kontrastmittel wird als Standardverfahren in der differentialdiagnostischen Abklärung von Atelektasen (AT) der Lunge eingesetzt. Ziel dieser Untersuchung war es, die diagnostische Treffsicherheit von B-Bild-Sonographie (US) und kontrastunterstützter Sonographie (KUS) im Vergleich zur CT hinsichtlich der Abgrenzbarkeit einer zentralen Raumforderung (ZR) von atelektatischen Lungengewebe und im Nachweis von fokalen Läsionen (FL) in obstruktionsbedingten Lungenatelektasen zu untersuchen. Material und Methoden: Von Mai 2004 bis Dezember 2009 wurden n=47 Patienten mit histologisch gesichertem zentralem Bronchialkarzinom und obstruktiver Atelektase mit CT, US und KUS (Sonovue, Bracco) untersucht. Beurteilt wurden Abgrenzbarkeit von AT und ZR sowie Nachweis von FL in der AT. Die Ultraschallbilder von US und KUS wurden von 2 gegeneinander verblindeten Untersuchern beurteilt, diskrepante Befunde wurden drittbefundet. Die CT-Bilder wurden von einem verblindeten Radiologen beurteilt. Ergebnisse: Ein zentrale TU Darstellung gelang im US bei 24/47, in der KUS bei 38/47 und in der CT bei 34/47 der Patienten (US vs KUS p=<0,05, US vs CT p=<0,05, KUS vs CT p=0,38). Es zeigen sich signifikante Unterschiede zugunsten der KUS und der CT gegenüber dem US, nicht aber zwischen KUS und CT. Ein Nachweis von FL gelang im US bei 6/47, in der KUS bei 15/47 und in der CT bei 8/47 der Patienten (US vs KUS p=<0,05, US vs CT p=0,69, KUS vs CT p=0,09). Hier ist nur der Unterschied zwischen der KUS und dem US signifikant. Schlussfolgerung: Bei obstruktiver AT ist die KUS der CT in der Abgrenzung eines zentralen TU ebenbürtig und dem konventionellen US überlegen

Aus der Geburtsstube von Nanokristallen: Computersimulationen der Aggregation von Ionen und der Entstehung geordneter Strukturen

The study of crystal nucleation represents a considerable challenge to both experiment and theory. Crystallisation from solutions is initiated by the association of only a few ions. The resulting aggregates are the embryonic precursors to crystals and exhibit diameters of less than a nanometre. While experimental studies offer a wide variety of insights at the macroscopic scale, the atomistic level of detail often remains elusive. On the other hand, computer simulation approaches may easily achieve microscopic resolution and hence appear particularly suited for analysis of the mechanisms of ion aggregation. On the basis of atomistic models, new insights are obtained into the early steps of ion association and the self-organisation of disordered aggregates into crystalline structures.Das Studium der Nukleation von Kristallen stellt eine immense Herausforderung sowohl an die Experimentatoren als auch an die Theoretiker dar. Die Bildung eines Kristalls aus einer Lösung beginnt mit dem Zusammenschluss einzelner Ionen zu kleinen Aggregaten. Diese embryonalen Vorstufen von Kristallen umfassen nur einige Teilchen und weisen Durchmesser von weniger als einem Nanometer auf. Experimentelle Untersuchungen sind oftmals auf die makro- und mesoskopische Größenskala beschränkt und können vergleichsweise wenige Informationen über die atomaren Aggregationsprozesse liefern. Molekulare Simulationen verlaufen im Gegensatz dazu unmittelbar auf der atomaren Detailstufe und stellen so eine hervorragende Ergänzung zum Experiment dar. Im Computer werden dabei Modellszenarien entwickelt, die Aufschlüsse über die elementaren Schritte der Aggregation von Ionen geben können und aufzeigen, wie sich zunächst ungeordnete Agglomerate allmählich zu periodisch geordneten Strukturen organisieren

Two-level system with noise: Blue's function approach

By using the random matrix approach and generalized Blue's function representation we solve analytically the model of an effective two-level system coupled to a noise reservoir. We show that calculated spectral properties of the system are in agreement with the numerically simulated results. We outline possible applications of the model in the field of condensed phase reactions.Comment: 17 pages LaTeX, 5 EPS figures include

Koordiniertes Klimahandeln zwischen „oben“ und „unten“

Der Umgang mit dem Klimawandel ist vor allem eine gesellschaftliche Aufgabe. Welche Herausforderungen entstehen dabei auf regionaler und lokaler Ebene? Neue Forschungsergebnisse zeigen, wie Probleme bei Klimaschutz und Klimaanpassung bewältigt werden können

The MHC2TA -168A>G gene polymorphism is not associated with rheumatoid arthritis in Austrian patients

An association between susceptibility to rheumatoid arthritis (RA) and a common -168A>G polymorphism in the MHC2TA gene with differential major histocompatibility complex (MHC) II molecule expression was recently reported in a Swedish population. The objective of the present study was to replicate this finding by examining the -168A>G polymorphism in an Austrian case–control study. Three hundred and sixty-two unrelated RA cases and 351 sex-matched and age-matched controls as well as 1,709 Austrian healthy individuals were genotyped. All participants were from the same ethnic background. Genotyping was performed using 5' allelic discrimination assays. The association between susceptibility to RA and the -168A>G single nucleotide polymorphism was examined by chi-square test. Comparison was made assuming a dominant effect (AG + GG genotypes versus AA genotype). In contrast to the primary report, the frequency of MHC2TA -168G allele carriers was not significantly different between patients and controls in the Austrian cohort. The homozygous MHC2TA -168 GG genotype was more frequent in matched controls than in Austrian RA patients. There was no association between the presence of RA-specific autoantibodies and the MHC2TA -168 GG genotype. In this cohort of Austrian patients, no association between the MHC2TA polymorphism and RA was found

Relação entre peso ao nascer, sexo do recém-nascido e tipo de parto

In order to assess the influence of birth weight on the type of birth two maternity hospitals whose patients were of different socio-economic levels were studied. 16,095 births were analysed. It was discovered that the incidence of cesarian sections increased with the increase in birth weight in both hospitals, but that in the private hospital the incidence was four times higher than in the hospital for the poor. No relation was found, in those women who received private treatment, between type of brith and birth weight. Among those babies who weighed 2500g or less at birth, there was found to be a significant predominance of girls and for those who weighed more than 4000g there was, equally, a larger proportion of boys.Foram estudadas duas maternidades que atendem a população de níveis sócio-econômicos heterogêneos para avaliar a influência do peso do recém-nascido no tipo de parto. Foram analisados 16.095 nascimento. Verificou-se aumento da incidência de cesareanas com o aumento do peso do recém-nascido, nas duas maternidades, mas na maternidade particular a incidência foi mais elevada em relação à maternidade assistencial. Chamou a atenção o fato da não associação entre o tipo de parto e o peso do recém-nascido nas mulheres que tiveram atendimento particular. A predominância do sexo feminino no grupo de peso de 2.500 g e menos foi estatisticamente significante e do mesmo modo a maior proporção do sexo masculino nos recém-nascidos com mais de 4.000 g

Random Matrix Theories in Quantum Physics: Common Concepts

We review the development of random-matrix theory (RMT) during the last decade. We emphasize both the theoretical aspects, and the application of the theory to a number of fields. These comprise chaotic and disordered systems, the localization problem, many-body quantum systems, the Calogero-Sutherland model, chiral symmetry breaking in QCD, and quantum gravity in two dimensions. The review is preceded by a brief historical survey of the developments of RMT and of localization theory since their inception. We emphasize the concepts common to the above-mentioned fields as well as the great diversity of RMT. In view of the universality of RMT, we suggest that the current development signals the emergence of a new "statistical mechanics": Stochasticity and general symmetry requirements lead to universal laws not based on dynamical principles.Comment: 178 pages, Revtex, 45 figures, submitted to Physics Report

Ring electrode for radio-frequency heating of the cornea: modelling and in vitro experiments

[EN] Radio-frequency thermokeratoplasty (RF-TKP) is a technique used to reshape the cornea curvature by means of thermal lesions using radio-frequency currents. This curvature change allows refractive disorders such as hyperopia to be corrected. A new electrode with ring geometry is proposed for RF-TKP. It was designed to create a single thermal lesion with a full-circle shape. Finite element models were developed, and the temperature distributions in the cornea were analysed for different ring electrode characteristics. The computer results indicated that the maximum temperature in the cornea was located in the vicinity of the ring electrode outer perimeter, and that the lesions had a semi-torus shape. The results also indicated that the electrode thickness, electrode radius and electrode thermal conductivity had a significant influence on the temperature distributions. In addition, in vitro experiments were performed on rabbit eyes. At 5 IN power the lesions were fully circular. Some lesions showed non-uniform characteristics along their circular path. Lesion depth depended on heating duration (60% of corneal thickness for 20s, and 30% for 10s). The results suggest that the critical shrinkage temperature (55-63degreesC) was reached at the central stroma and along the entire circular path in all the cases.Berjano, E.; Saiz Rodríguez, FJ.; Alió, J.; Ferrero, JM. (2003). Ring electrode for radio-frequency heating of the cornea: modelling and in vitro experiments. Medical & Biological Engineering & Computing. 41(6):630-639. https://doi.org/10.1007/BF02349970S630639416Alió, J. L., Ismail, M. M., Artola, A., andPérez-Santonja, J. J. (1997a): ‘Correction of hyperopia induced by photorefractive keratectomy using non-contact Ho: YAG laser thermal keratoplasty’,J. Refract. Surg.,13, pp. 13–16Alió, J. L., Ismail, M. M., andSanchez, J. L. (1997b): ‘Correction of hyperopia with non-contact Ho: YAG laser thermal keratoplasty’,J. Refract. Surg.,13, pp. 17–22Alió, J. 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