Anlage von kontinuierlichen Nervus femoralis Kathetern zur Analgesie bei komplexen Knieoperationen. Ist ein Stimulationskatheter der konventionellen Methode überlegen ? Eine randomisierte, kontrollierte Studie

Kontinuierliche Nervus femoralis Katheter liefern eine effektive und nebenwirkungsarme Regionalanalgesie bei komplexen Knieoperationen mit dem Vorteil der postoperativ beschleunigten funktionellen Rehabilitation. Bisher wurden Femoraliskatheter durch „blindes“ Vorschieben des Katheters über eine Stimulationskanüle gelegt. Die endgültige Katheterlage dabei bleibt zunächst ungewiss und wird in der Regel erst durch Erfolg oder Misserfolg bei Injektion von Lokalanästhetikum objektiviert. Neu eingeführte Stimulationskatheter besitzen den potentiellen Vorteil, schon während des Vorschiebens die korrekte Platzierung in der Nähe des Nervs zu kontrollieren. Um zu erfahren, ob sich durch diese neue Technik der präziseren Katheterpositionierungen auch ein besserer Blockadeerfolg nachweisen läßt, vergleichen wir die Stimulationskatheter mit der konventionellen Methode an 81 Patienten vor komplexen Knieoperationen im Rahmen einer prospektiven, randomisierten Studie. Die Anschlagsgeschwindigkeit beider Techniken ist für den sensiblen wie für den motorischen Block gleich. Auch die Dauer der Katheteranlage unterscheidet sich mit 4 Min. für die konventionelle Methode und 5 Min. für die Stimulationskatheter kaum. In beiden Kathetergruppen gelangen erfolgreiche Platzierungen (Stromstärke via Katheter ≤ 0,5 mA) in jeweils 42 % der Fälle im ersten Versuch. Von den Stimulationskathetern mussten 22 (58 %) teilweise bis zu 20 mal repositioniert werden und zwei konnten innerhalb von 20 Minuten nicht korrekt platziert werden. Der Stimulationskatheter stellt für die kontinuierliche Nervus femoralis Blockade für den erfahrenen Arzt keine Verbesserung zur konventionellen Methode dar. Nebenaspekt 1: Als weiterer Befund wurde bei den Patienten nach Injektion des Lokalanästhetikums die Methämoglobinkonzentration bestimmt. Das zur Blockinitiierung als Bolus über den Katheter verabreichte Lokalanästhetikum Prilocain ist dafür bekannt, gelegentlich eine Methämoglobinbildung in unterschiedlichem Ausmaß beim Patienten hervorzurufen. Über die Gründe für die Intensität dieser Nebenwirkung bei einigen Patienten ist noch wenig bekannt. Eine Studie an 162 Patienten, die 300 mg oder 400 mg Prilocain über eine von drei Kathetertechniken, einem Nervus femoralis Katheter, einem kombinierten Femoralis/Ischiadikuskatheter oder einem Psoas compartment Katheter, verabreicht bekamen und deren Methämoglobinkonzentrationen im Blut drei Stunden danach untersucht wurde, sollte Einflussfaktoren aufzeigen. Eine Analyse zahlreicher potentieller Faktoren ergab folgende hoch signifikante Parameter für hohe Methämoglobinwerte: eine Prilocaindosis von 400 mg, weibliches Geschlecht, niedriges Alter sowie eine höhere Konzentration bzw. geringere Verdünnung des Prilocains. Demnach sollten gerade bei jüngeren Patientinnen eine Dosis von 400 mg Prilocain über den Katheter nicht überschritten werden und zudem vermehrt Blutkontrollen des Methämoglobins stattfinden. Bei einem Methämoglobinwert von über 15 % empfehlen wir die Gabe von 1 mg/kg Methylenblau. Nebenaspekt 2: Regionalanästhesieverfahren wie die Anlage eines Femoraliskatheters gehen für den wachen Patienten oft mit Angst und Schmerz einher. Unter dem daraus resultierenden verminderten Patientenkomfort und in der Folge einer reduzierten Patientenkooperativität leidet wiederum die Qualität der Regionalanästhesie. In dem dritten Teil der Studie sollte die Wirkung einer Anxiolyse und einer Analgesie auf das Empfinden des Patienten und auf die Arbeitserleichterung für den Anästhesisten analysiert werden. 174 Patienten erhielten nach oraler Prämedikation mit 20 mg Dikaliumclorazepat intravenös 0,1 mg Fentanyl, 3 mg Midazolam oder physiologische Kochsalzlösung als Plazebo vor Anlage einer peripheren Kathetertechnik. Unmittelbar nach dem Verfahren beurteilte der Patient sein subjektives Empfinden auf einer visuellen Analogskala von 0 – 100 mm (0 = gar nicht schlimm, 100 = extrem unangenehm) und der Arzt entsprechend die Patientenkooperativität während der Katheteranlage auf einer Likert-Skala. Die Patientenbeurteilung wurde nach 24 Stunden erneut erbeten, woraufhin auch eine mögliche Amnesie untersucht werden konnte. Langdauernde Katheteranlagen und weibliches Geschlecht erhöhten das Mißempfinden, wogegen Fentanyl es senkte. Ohne Einfluss auf das Empfinden waren Midazolam, Alter, BMI und die Katheterart (Femoraliskatheter, Kombination aus Femoralis- und Ischiadikusblock sowie Psoas compartment Block). Eine schlechte oder sehr schlechte Kooperativität wurde bei 26 % der Midazolampatienten bescheinigt (9 % bei Plazebo und 3 % bei Fentanyl). Mit 27 % der Midazolamgruppe, 9 % der Fentanylgruppe und 6 % der Plazebogruppe ergaben sich Erinnerungslücken zur Katheteranlage. Fentanyl allein konnte Patientenkomfort und Patientenkooperativität signifikant verbessern und wird daher zur intravenösen Verabreichung vor Anlage einer peripheren Regionalanästhesie angeraten

Layout of Graphs with Bounded Tree-Width

A \emph{queue layout} of a graph consists of a total order of the vertices, and a partition of the edges into \emph{queues}, such that no two edges in the same queue are nested. The minimum number of queues in a queue layout of a graph is its \emph{queue-number}. A \emph{three-dimensional (straight-line grid) drawing} of a graph represents the vertices by points in $\mathbb{Z}^3$ and the edges by non-crossing line-segments. This paper contributes three main results: (1) It is proved that the minimum volume of a certain type of three-dimensional drawing of a graph $G$ is closely related to the queue-number of $G$. In particular, if $G$ is an $n$-vertex member of a proper minor-closed family of graphs (such as a planar graph), then $G$ has a $O(1)\times O(1)\times O(n)$ drawing if and only if $G$ has O(1) queue-number. (2) It is proved that queue-number is bounded by tree-width, thus resolving an open problem due to Ganley and Heath (2001), and disproving a conjecture of Pemmaraju (1992). This result provides renewed hope for the positive resolution of a number of open problems in the theory of queue layouts. (3) It is proved that graphs of bounded tree-width have three-dimensional drawings with O(n) volume. This is the most general family of graphs known to admit three-dimensional drawings with O(n) volume. The proofs depend upon our results regarding \emph{track layouts} and \emph{tree-partitions} of graphs, which may be of independent interest.Comment: This is a revised version of a journal paper submitted in October 2002. This paper incorporates the following conference papers: (1) Dujmovic', Morin & Wood. Path-width and three-dimensional straight-line grid drawings of graphs (GD'02), LNCS 2528:42-53, Springer, 2002. (2) Wood. Queue layouts, tree-width, and three-dimensional graph drawing (FSTTCS'02), LNCS 2556:348--359, Springer, 2002. (3) Dujmovic' & Wood. Tree-partitions of $k$-trees with applications in graph layout (WG '03), LNCS 2880:205-217, 200

Photometric and spectroscopic observations of three rapidly rotating late-type stars: EY Dra, V374 Peg and GSC 02038-00293

Here, BV(RI)c broad band photometry and intermediate resolution spectroscopy in Halpha region are presented for two rapidly rotating late-type stars: EY Dra and V374 Peg. For a third rapid rotator, GSC 02038-00293, intermediate resolution Halpha spectroscopy and low resolution spectroscopy are used for spectral classification and stellar parameter investigation of this poorly known object. The low resolution spectrum of GSC 02038-00293 clearly indicates that it is a K-type star. Its intermediate resolution spectrum can be best fitted with a model with Teff=4750K and vsini=90km/s, indicating a very rapidly rotating mid-K star. The Halpha line strength is variable, indicating changing chromospheric emission on GSC 02038-00293. In the case of EY Dra and V374 Peg, the stellar activity in the photosphere is investigated from the photometric observations, and in the chromosphere from the Halpha line. The enhanced chromospheric emission in EY Dra correlates well with the location of the photospheric active regions, indicating that these features are spatially collocated. Hints of this behaviour are also seen in V374 Peg, but it cannot be confirmed from the current data. The photospheric activity patterns in EY Dra are stable during one observing run lasting several nights, whereas in V374 Peg large night-to-night variations are seen. Two large flares, one in the Halpha observations and one from the broadband photometry, and twelve smaller ones were detected in V374 Peg during the observations spanning nine nights. The energy of the photometrically detected largest flare is estimated to be 4.25x10^31 - 4.3x10^32 ergs, depending on the waveband. Comparing the activity patterns in these two stars, which are just below and above the mass limit of full convection, is crucial for understanding dynamo operation in stars with different internal structures.Comment: Accepted for publication in Astronomische Nachrichten (Astronomical Notes

Environmental influence of problematic social relationships on adolescents' daily cortisol secretion : a monozygotic twin-difference study

BACKGROUND: This study investigated the potential environmental effects of peer victimization and the quality of relationships with parents and friends on diurnal cortisol secretion in mid-adolescence. METHOD: This study used the monozygotic (MZ) twin-difference design to control for genetic effects and thus estimate the unique environmental influences on diurnal cortisol. Participants were 136 MZ twin pairs (74 female pairs) for whom cortisol was assessed four times per day over four collection days grouped in a 2-week period in grade 8 (mean age = 14.07 years). Participants also provided self-reports of peer victimization from grade 4 to grade 8 and of the relationship quality with the mother, father and best friend in grade 8. RESULTS: The expected pattern of diurnal cortisol secretion was observed, with high levels at awakening followed by an increase 30 min later and a progressive decrease subsequently. Controlling for a host of confounders, only within-twin pair differences in peer victimization and a problematic relationship with the mother were significantly linked to twin differences in diurnal cortisol secretion. Specifically, whereas a more problematic mother-child relationship was associated with morning cortisol secretion, peer victimization was linked to cortisol secretion later in the day (diurnal slope). CONCLUSIONS: Controlling for genetic influences and other confounders, stressful relationships with peers and the mother exert unique and time-specific environmental influences on the pattern of diurnal cortisol secretion in mid-adolescence

Does cortisol moderate the environmental association between peer victimization and depression symptoms? a genetically informed twin study

Many youths who are victimized by peers suffer from depression symptoms. However, not all bullying victims become depressed and individuals’ biological sensitivity may play an important moderating role in this regard. In line with this notion, peer victimization has been associated with increased depressive symptoms in youth with higher basal cortisol secretion. It is unclear, however, whether this moderating effect of cortisol really concerns the environmental effect of peer victimization on depression. Indeed, genetic factors can also influence individuals’ environmental experiences, including peer victimization, and part of these genetic factors may be those associated with depression. Using a genetically informed design based on 159 monozygotic and 120 dizygotic twin pairs (52% girls) assessed at age 14 years, this study examined whether cortisol secretion moderates the environmental or the genetic association between peer victimization and depression symptoms. Salivary cortisol at awakening was obtained with buccal swabs during four school week days. Peer victimization and depression were assessed via self-reports. Cholesky modeling revealed that peer victimization was associated with depression symptoms via both genetic and environmental pathways. Moreover, the environmental association between peer victimization and depression symptoms steadily increased with increasing levels of morning cortisol. The genetic association between peer victimization and depression symptoms also varied, albeit less, as a function of individuals’ cortisol secretion. These findings support the hypothesis that peer victimization increases internalizing psychopathology mainly in youth with heightened biological reactivity to environmental conditions

Evidence of a unique and common genetic etiology between the CAR and the remaining part of the diurnal cycle : a study of 14 year-old twins

Introduction By and large, studies have reported moderate contributions of genetic factors to cortisol secreted in the early morning and even smaller estimates later in the day. In contrast, the cortisol awakening response (CAR) has shown much stronger heritability estimates, which prompted the hypothesis that the etiology of cortisol secretion may vary according to the time of day. A direct test of this possibility has, however, not yet been performed. Objective To describe the specific and common etiology of the CAR, awakening level and cortisol change from morning to evening in an age-homogenous sample of twin adolescents. Methods A total of 592 participants of the Québec Newborn Twin Study, a population-based 1995–1998 cohort of families with twins in Canada, have collected saliva at awakening, 30 min later, at the end of afternoon and in the evening over four collection days. Results Multivariate Cholesky models showed both specific and common sources of variance between the CAR, awakening and cortisol diurnal change. The CAR had the strongest heritability estimates, which, for the most part, did not overlap with the other indicators. Conversely, similar magnitudes of genetic and environmental contributions were detected at awakening and for diurnal change, which partially overlapped. Conclusion Our study unraveled differences between the latent etiologies of the CAR and the rest of the diurnal cycle, which may contribute to identify regulatory genes and environments and detangle how these indicators each relate to physical and mental health

The Quebec newborn twin study at 21

This paper is a revised and updated edition of a previous description of the Quebec Newborn Twin Study (QNTS), an ongoing prospective longitudinal follow-up of a birth cohort of twins born between 1995 and 1998 in the greater Montreal area, Québec, Canada. The goal of QNTS is to document individual differences in the cognitive, behavioral, and social-emotional aspects of developmental health across childhood, their early genetic and environmental determinants, as well as their putative role in later social-emotional adjustment, school, health, and occupational outcomes. A total of 662 families of twins were initially assessed when the twins were aged 6 months. These twins and their family were then followed regularly. QNTS now has 16 waves of data collected or planned, including 5 in preschool. Over the last 24 years, a broad range of physiological, cognitive, behavioral, school, and health phenotypes were documented longitudinally through multi-informant and multimethod measurements. QNTS also entails extended and detailed multilevel assessments of proximal (e.g., parenting behaviors, peer relationships) and distal (e.g., family income) features of the child’s environment. QNTS children and a subset of their parents have been genotyped, allowing for the computation of a variety of polygenic scores. This detailed longitudinal information makes QNTS uniquely suited for the study of the role of the early years and gene–environment transactions in development

EUROCODE 2: BACKGROUND & APPLICATIONS DESIGN OF CONCRETE BUILDINGS Worked examples

This document is a report with worked examples presenting step-by-step the design of a reinforced concrete cast on site building following Eurocode 2. The design process has been divided between different authors, some of whom were involved in the preparation and/or assessment of Eurocode 2. Each chapter of the report focuses on a different step in the design process: conceptual design, structural analyses, limit states design and verification, detailing of the reinforcement as well as some geotechnical aspects of building design. Last chapter gives general overview of the fire design according to the Eurocodes. The materials were prepared and presented at the workshop “Eurocode 2: Design of Concrete Buildings” held on 20 21 October 2011 in Brussels, Belgium. The workshop was organized by JRC with the support of DG ENTR and CEN, and in collaboration with CEN/TC250/Sub-Committee 2. The document is part of the Report Series ‘Support to the implementation, harmonization and further development of the Eurocodes’ prepared by JRC in collaboration with DG ENTR and CEN/TC250 “Structural Eurocodes”.JRC.G.5-European laboratory for structural assessmen

Kondo Effects and Multipolar Order in the cubic PrTr2Al20 (Tr=Ti, V)

Our single crystal study reveals that PrTr2Al20 (Tr = Ti and V) provides the first examples of a cubic {\Gamma}3 nonmagnetic ground doublet system that shows the Kondo effect including a -ln T dependent resistivity. The {\Gamma}3 quadrupolar moments in PrV2Al20 induce anomalous metallic behavior through hybridization with conduction electrons, such as T^{1/2} dependent resistivity and susceptibility below ~ 20 K down to its ordering temperature T_O = 0.6 K. In PrTi2Al20, however, quadrupoles are well-localized and exhibit an order at T_O = 2.0 K. Stronger Kondo coupling in PrV2Al20 than in PrTi2Al20 suppresses quadrupolar ordering, and instead promotes hybridization between the {\Gamma}3 doublet and conduction electrons, leading to most likely the quadrupolar Kondo effect.Comment: 12 pages, 4 figure