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Purpose
To assess potential cognitive deficits under the influence of static magnetic fields at various field strengths some studies already exist. These studies were not focused on attention as the most vulnerable cognitive function. Additionally, mostly no magnetic resonance imaging (MRI) sequences were performed.
Materials and Methods
In all, 25 right-handed men were enrolled in this study. All subjects underwent one MRI examination of 63 minutes at 1.5 T and one at 7 T within an interval of 10 to 30 days. The order of the examinations was randomized. Subjects were referred to six standardized neuropsychological tests strictly focused on attention immediately before and after each MRI examination. Differences in neuropsychological variables between the timepoints before and after each MRI examination were assessed and P-values were calculated
Results
Only six subtests revealed significant differences between pre- and post-MRI. In these tests the subjects achieved better results in post-MRI testing than in pre-MRI testing (P = 0.013–0.032). The other tests revealed no significant results.
Conclusion
The improvement in post-MRI testing is only explicable as a result of learning effects. MRI examinations, even in ultrahigh-field scanners, do not seem to have any persisting influence on the attention networks of human cognition immediately after exposure.
Various models have been proposed for the prediction of the necessary support pressure at the face of a shallow tunnel. To assess their quality, the collapse of a tunnel face was modelled with small-scale model tests at single gravity. The development of the failure mechanism and the support force at the face in dry sand were investigated. The observed displacement patterns show a negligible influence of overburden on the extent and evolution of the failure zone. The latter is significantly influenced, though, by the initial density of the sand: in dense sand a chimney-wedge-type collapse mechanism developed, which propagated towards the soil surface. Initially, loose sand did not show any discrete collapse mechanism. The necessary support force was neither influenced by the overburden nor the initial density. A comparison with quantitative predictions by several theoretical models showed that the measured necessary support pressure is overestimated by most of the models. Those by Vermeer/Ruse and Léca/Dormieux showed the best agreement to the measurements.
Moderne Bauwerke müssen heute eine hohe energetische Leistungsfähigkeit aufweisen und gleichzeitig alle einwirkenden Lasten sicher abtragen. Dies stellt insbesondere in Erdbebengebieten hohe Anforderungen an die verwendeten Baustoffe. Am baupraktischen Beispiel einer Doppelhaushälfte wird demonstriert, dass die Symbiose aus energieeffizientem und gleichzeitig erdbebensicherem Bauen in der höchsten deutschen Erdbebenzone mit monolithischem Ziegelmauerwerk gut realisierbar ist. Als Ziegelmauerwerk werden für die Außenwände wärmetechnisch optimierte Hochlochziegel verwendet, die sowohl die Anforderungen der Energieeinsparverordnung 2009 als auch die Anforderungen an Mauerwerkbaustoffe nach den aktuellen Erdbebennormen erfüllen. Der Erdbebennachweis der Doppelhaushälfte erfolgt mit einem nichtlinearen Nachweisverfahren, das für eine einfache praktische Anwendung programmtechnisch umgesetzt wurde. Für den Nachweis wurden aus zyklischen Schubwandversuchen ermittelte Last-Verformungskurven verwendet. Das gesamte in Deutschland noch nicht normativ geregelte Nachweiskonzept wurde im Rahmen einer Zustimmung im Einzelfall geprüft und genehmigt.
In Valais, Switzerland, Scots pines (Pinus sylvestris L.) are declining, mainly following drought. To assess the impact of drought on tree growth and survival, an irrigation experiment was initiated in 2003 in a mature pine forest, approximately doubling the annual precipitation. Tree crown transparency (lack of foliage) and leaf area index (LAI) were annually assessed. Seven irrigated and six control trees were felled in 2006, and needles, stem discs and branches were taken for growth analysis. Irrigation in 2004 and 2005, both with below-average precipitation, increased needle size, area and mass, stem growth and, with a 1-year delay, shoot length. This led to a relative decrease in tree crown transparency (−14%) and to an increase in stand LAI (+20%). Irrigation increased needle length by 70%, shoot length by 100% and ring width by 120%, regardless of crown transparency. Crown transparency correlated positively with mean needle size, shoot length and ring width and negatively with specific leaf area. Trees with high crown transparency (low growth, short needles) experienced similar increases in needle mass and growth with irrigation than trees with low transparency (high growth, long needles), indicating that seemingly declining trees were able to ‘recover’ when water supply became sufficient. A simple drought index before and during the irrigation explained most of the variation found in the parameters for both irrigated and control trees.
Bilaterale stromale Hornhauttrübungen sind für den Augenarzt eine differenzialdiagnostische Herausforderung. Im folgenden Beitrag werden 2 Patieninnen (30 und 36 Jahre) mit unterschiedlich stark ausgeprägter stromaler diffuser Hornhauttrübung vorgestellt. Patientin 1 war kleinwüchsig (114 cm) und Patientin 2 normal groß (172 cm). Beide Patientinnen wiesen veränderte Gelenkstrukturen an Hand und Fußgelenken sowie diffuse stromale Hornhauttrübungen auf. Des Weiteren lagen eine Mitral- und Aorteninsuffizienz (Patientin 1) bzw. eine Aorteninsuffizienz (Patientin 2) vor. Die stromalen diffusen Hornhauttrübungen ließen im Zusammenhang mit den Gelenkveränderungen ein Scheie-Syndrom vermuten. Therapeutisch ist bei Patienten mit Visusminderung eine (lamelläre) Keratoplastik sinnvoll.
Differential modulation of valence and arousal in high-alexithymic and low-alexithymic individuals
(2010)
High-alexithymic individuals are characterized by an impaired ability to identify and communicate emotions whereas low-alexithymic individuals have a wide-ranging ability to deal with emotions. This study examined the hypothesis that valence and arousal modifications of emotional stimuli differentially modulate cortical regions in high-alexithymic and low-alexithymic individuals. To this end, 28 high-alexithymic and 25 low-alexithymic individuals were investigated with event-related fMRI using visual emotional stimuli. We found differential neural activations in the dorsal anterior cingulate, the insula and the amygdala. We suggest that these differences may account for the impaired ability of high-alexithymic individuals to appropriately handle emotional stimuli.
Im Herbst 2009 wurde das “Deutsche Gütesiegel Nachhaltiges Bauen” für die Gebäudetypen Industriebauten und Handelsbauten offiziell vorgestellt. Die Ökobilanz als wichtiger Baustein der Nachhaltigkeitsbewertung wird somit auch im Industrie- und Gewerbebau zukünftig stark an Bedeutung gewinnen.
Der vorliegende Beitrag beinhaltet einen Vergleich der Umweltleistung verschiedener Bauweisen des Industrie- und Gewerbebaus, die durch die Ökobilanzierung quantifizierbar wird, anhand von momentan verfügbaren Daten und Methoden. Es werden ausgewählte Ergebnisse sowie vorhandene Unsicherheiten und daraus resultierender Forschungsbedarf aufgezeigt.
Das verbraucherschützende Widerrufsrecht ist in die Jahre gekommen. Als Ergebnis der zunehmenden Rechtszersplitterung im europäischen Richtlinienrecht hat sich eine unüberschaubare Bandbreite an Ausgestaltungsformen in den mitgliedstaatlichen Rechtssystemen herausgebildet. Effektivitätseinbußen, Wettbewerbsverzerrungen und ein hohes Maß an Rechtsunsicherheit sind die Folgen. Zurückführen lässt sich die kostenintensive Fragmentierung des Verbrauchervertragsrechts auf die bisherige Regelungspolitik der Mindestharmonisierung, die es den Mitgliedstaaten erlaubt, von dem durch die Richtlinien gesetzten Mindeststandard durch „überschießende Umsetzung” abzuweichen. Der Unionsgesetzgeber versucht dem vermehrt durch einen Prozess der Vollharmonisierung zu begegnen: Neben Reformen der Richtlinie über Verbraucherkredite (VerbrKrRL) sowie der Timesharing-Richtlinie (TimesharingRL), liegt seit dem 8. Oktober 2008 nunmehr auch der Entwurf einer Rahmenrichtlinie über die Rechte der Verbraucher (VRRL-E) vor. Danach sollen die bisherigen Richtlinien über Haustürgeschäfte (HaustürgeschäfteRL), Fernabsatzverträge (FARL), missbräuchliche Klauseln sowie Verbrauchsgüterkäufe vereinigt werden. Für das verbraucherschützende Widerrufsrecht ist damit zum einen die Herausbildung einheitlicher Kernelemente verbunden, zum anderen tritt es in Konkurrenz zu umfassenden Informationspflichten, die ebenfalls den Schutz des Verbrauchers vor dem unüberlegten Abschluss riskanter bzw. nachteiliger Verträge zum Ziel haben.
Angesichts dieser Entwicklung stellt sich im Folgenden die Frage nach der Zukunft des unionsrechtlichen Widerrufsrechts. Von besonderer Bedeutung ist dabei die Klärung des Verhältnisses zu den verbraucherschützenden Informationspflichten. Dazu bedarf es zunächst der Herausarbeitung einheitlicher Kernelemente des Widerrufsrechts im vollharmonisierten Richtlinienrecht (II.) sowie einer Systematisierung der sekundärrechtlichen Informationspflichten im Anschluss eine kritische Gegenüberstellung der Vor- und Nachteile beider Schutzinstrumente erfolgen kann (IV.).
Die Konzernrechnungslegung
(2010)
Chalcogenide glass materials as membranes for potentiometric sensors for chemical analysis in solutions have been studied since more than 20 years. In this work, an electrolyte–insulator–semiconductor structure was combined with chalcogenide glass membranes prepared by means of the pulsed laser deposition technique. Depending on the membrane composition a selectivity to different ions (Cd2+ and Pb2+) is achieved. The different sensor membranes have been physically characterised using microscopy, ellipsometry, profilometry, atomic force microscopy (AFM), scanning electron microscopy (SEM) and Rutherford backscattering spectrometry (RBS). The electrochemical behaviour has been investigated via capacitance/voltage (C/V) and constant capacitance (ConCap) measurements and results in a Cd2+ sensitivity of 23.1 ± 0.6 mV per decade in a linear range from 7 × 10−6 to 10−2 mol/l and 24.4 ± 0.5 mV per decade in a linear range from 5 × 10−6 to 10−2 mol/l for Pb2+, respectively.
A handheld sensor system for the online measurement of hydrogen peroxide (H2O2) in aseptic sterilisation processes has been developed. It is based on a calorimetric-type gas sensor that consists of a differential set-up of two temperature sensors, of which one is catalytically activated and the second one is passivated and used as reference. The sensor principle relies in detecting a rise in temperature on the active sensor due to the exothermic reaction of H2O2 on the catalytic surface. To characterise the sensor system towards H2O2 sensitivity and other influencing factors, measurements have been carried out both at an experimental set-up and a manufacturer's sterilisation machine. Physical sensor characterisation was done by means of the optical microscopy.
Design and initial performance of PlanTIS: a high-resolution positron emission tomograph for plants
(2010)
Positron emitters such as 11C, 13N and 18F and their labelled compounds are widely used in clinical diagnosis and animal studies, but can also be used to study metabolic and physiological functions in plants dynamically and in vivo. A very particular tracer molecule is 11CO2 since it can be applied to a leaf as a gas. We have developed a Plant Tomographic Imaging System (PlanTIS), a high-resolution PET scanner for plant studies. Detectors, front-end electronics and data acquisition architecture of the scanner are based on the ClearPET™ system. The detectors consist of LSO and LuYAP crystals in phoswich configuration which are coupled to position-sensitive photomultiplier tubes. Signals are continuously sampled by free running ADCs, and data are stored in a list mode format. The detectors are arranged in a horizontal plane to allow the plants to be measured in the natural upright position. Two groups of four detector modules stand face-to-face and rotate around the field-of-view. This special system geometry requires dedicated image reconstruction and normalization procedures. We present the initial performance of the detector system and first phantom and plant measurements.
The CellDrum technology (The term 'CellDrum technology' includes a couple of slightly different technological setups for measuring lateral mechanical tension in various types of cell monolayers or 3D-tissue constructs) was designed to quantify the contraction rate and mechanical tension of self-exciting cardiac myocytes. Cells were grown either within flexible, circular collagen gels or as monolayer on top of respective 1-mum thin silicone membranes. Membrane and cells were bulged outwards by air pressure. This biaxial strain distribution is rather similar the beating, blood-filled heart. The setup allowed presetting the mechanical residual stress level externally by adjusting the centre deflection, thus, mimicking hypertension in vitro. Tension was measured as oscillating differential pressure change between chamber and environment. A 0.5-mm thick collagen-cardiac myocyte tissue construct induced after 2 days of culturing (initial cell density 2 x 10(4) cells/ml), a mechanical tension of 1.62 +/- 0.17 microN/mm(2). Mechanical load is an important growth regulator in the developing heart, and the orientation and alignment of cardiomyocytes is stress sensitive. Therefore, it was necessary to develop the CellDrum technology with its biaxial stress-strain distribution and defined mechanical boundary conditions. Cells were exposed to strain in two directions, radially and circumferentially, which is similar to biaxial loading in real heart tissues. Thus, from a biomechanical point of view, the system is preferable to previous setups based on uniaxial stretching.
Objective: As high-field cardiac MRI (CMR) becomes more widespread the propensity of ECG to interference from electromagnetic fields (EMF) and to magneto-hydrodynamic (MHD) effects increases and with it the motivation for a CMR triggering alternative. This study explores the suitability of acoustic cardiac triggering (ACT) for left ventricular (LV) function assessment in healthy subjects (n=14). Methods: Quantitative analysis of 2D CINE steady-state free precession (SSFP) images was conducted to compare ACT’s performance with vector ECG (VCG). Endocardial border sharpness (EBS) was examined paralleled by quantitative LV function assessment. Results: Unlike VCG, ACT provided signal traces free of interference from EMF or MHD effects. In the case of correct Rwave recognition, VCG-triggered 2D CINE SSFP was immune to cardiac motion effects—even at 3.0 T. However, VCG-triggered 2D SSFP CINE imaging was prone to cardiac motion and EBS degradation if R-wave misregistration occurred. ACT-triggered acquisitions yielded LV parameters (end-diastolic volume (EDV), endsystolic volume (ESV), stroke volume (SV), ejection fraction (EF) and left ventricular mass (LVM)) comparable with those derived fromVCG-triggered acquisitions (1.5 T: ESVVCG=(56± 17) ml, EDVVCG=(151±32)ml, LVMVCG=(97±27) g, SVVCG=(94± 19)ml, EFVCG=(63±5)% cf. ESVACT= (56±18) ml, EDVACT=(147±36) ml, LVMACT=(102±29) g, SVACT=(91± 22) ml, EFACT=(62±6)%; 3.0 T: ESVVCG=(55±21) ml, EDVVCG=(151±32) ml, LVMVCG=(101±27) g, SVVCG=(96±15) ml, EFVCG=(65±7)% cf. ESVACT=(54±20) ml, EDVACT=(146±35) ml, LVMACT= (101±30) g, SVACT=(92±17) ml, EFACT=(64±6)%). Conclusions: ACT’s intrinsic insensitivity to interference from electromagnetic fields renders
Comparison of intravenous immunoglobulins for naturally occurring autoantibodies against amyloid-β
(2010)
Intravenous immunoglobulins (IVIG) are currently used for therapeutic purposes in autoimmune disorders. Recently, we demonstrated the presence of naturally occurring antibodies against amyloid- β (nAbs-Aβ) within the pool of IVIG. In this study, we compared different brands of IVIG for nAbs-Aβ and have found differences in the specificity of the nAbs-Aβ towards Aβ1–40 and Aβ1–42 . We analyzed the influence of a pH-shift over the course of antibody storage using ELISA and investigated antibody dimerization at acidic and neutral pH as well as differences in the IgG subclass distributions among the IVIG using both HPLC and a nephelometric assay. Furthermore, we investigated the epitope region of purified nAbs-Aβ. The differences found in Aβ specificity are not directly proportionate to the binding nature of these antibodies when administered in vivo. This information, however, may serve as a guide when choosing the commercial source of IVIG for therapeutic applications in Alzheimer's disease
The objectives of the present work are to characterize the Gas Metal Arc Welding process of DP 600 sheet steel and to summarize the modelling techniques. The time-temperature evolution during the welding cycle was measured experimentally and modelled with the softwaretool SimWeld. To model the phase transformations during the welding cycle dilatometer tests were done to quantify the parameters for phase field modelling by MICRESS®. The important input parameters are interface mobility, nucleation density, etc. A contribution was made to include austenite to bainite transformation in MICRESS®. This is useful to predict the microstructure in the fast cooling segments. The phase transformation model is capable to predict the microstructure along the heating and cooling cycles of welding. Tensile tests have shown the evidence of failure at the heat affected zone, which has the ferrite-tempered martensite microstructure.
Objectives
Interest in cardiovascular magnetic resonance (CMR) at 7 T is motivated by the expected increase in spatial and temporal resolution, but the method is technically challenging. We examined the feasibility of cardiac chamber quantification at 7 T.
Methods
A stack of short axes covering the left ventricle was obtained in nine healthy male volunteers. At 1.5 T, steady-state free precession (SSFP) and fast gradient echo (FGRE) cine imaging with 7 mm slice thickness (STH) were used. At 7 T, FGRE with 7 mm and 4 mm STH were applied. End-diastolic volume, end-systolic volume, ejection fraction and mass were calculated.
Results
All 7 T examinations provided excellent blood/myocardium contrast for all slice directions. No significant difference was found regarding ejection fraction and cardiac volumes between SSFP at 1.5 T and FGRE at 7 T, while volumes obtained from FGRE at 1.5 T were underestimated. Cardiac mass derived from FGRE at 1.5 and 7 T was larger than obtained from SSFP at 1.5 T. Agreement of volumes and mass between SSFP at 1.5 T and FGRE improved for FGRE at 7 T when combined with an STH reduction to 4 mm.
Conclusions
This pilot study demonstrates that cardiac chamber quantification at 7 T using FGRE is feasible and agrees closely with SSFP at 1.5 T.
Capacitive field-effect electrolyte-diamond-insulator-semiconductor (EDIS) structures with O-terminated nanocrystalline diamond (NCD) as sensitive gate material have been realized and investigated for the detection of pH, penicillin concentration, and layer-by-layer adsorption of polyelectrolytes. The surface oxidizing procedure of NCD thin films as well as the seeding and NCD growth process on a Si-SiO2 substrate have been improved to provide high pH-sensitive, non-porous thin films without damage of the underlying SiO2 layer and with a high coverage of O-terminated sites. The NCD surface topography, roughness, and coverage of the surface groups have been characterized by SEM, AFM and XPS methods. The EDIS sensors with O-terminated NCD film treated in oxidizing boiling mixture for 45 min show a pH sensitivity of about 50 mV/pH. The pH-sensitive properties of the NCD have been used to develop an EDIS-based penicillin biosensor with high sensitivity (65-70 mV/decade in the concentration range of 0.25-2.5 mM penicillin G) and low detection limit (5 μM). The results of label-free electrical detection of layer-by-layer adsorption of charged polyelectrolytes are presented, too.
A novel strategy for enhanced field-effect biosensing using capacitive electrolyte–insulator–semiconductor (EIS) structures functionalised with pH-responsive weak polyelectrolyte/enzyme or dendrimer/enzyme multilayers is presented. The feasibility of the proposed approach is exemplarily demonstrated by realising a penicillin biosensor based on a capacitive p-Si–SiO2 EIS structure functionalised with a poly(allylamine hydrochloride) (PAH)/penicillinase and a poly(amidoamine) dendrimer/penicillinase multilayer. The developed sensors response to changes in both the local pH value near the gate surface and the charge of macromolecules induced via enzymatic reaction, resulting in a higher sensitivity. For comparison, an EIS penicillin biosensor with adsorptively immobilised penicillinase has been also studied. The highest penicillin sensitivity of 100 mV/dec has been observed for the EIS sensor functionalised with the PAH/penicillinase multilayer. The lower and upper detection limit was around 20 µM and 10 mM, respectively. In addition, an incorporation of enzymes in a multilayer prepared by layer-by-layer technique provides a larger amount of immobilised enzymes per sensor area, reduces enzyme leaching effects and thus, enhances the biosensor lifetime (the loss of penicillin sensitivity after 2 months was 10–12%).
C-terminal truncation of a metagenome-derived detergent protease for effective expression in E. coli
(2010)
Recently, a new alkaline protease named HP70 showing highest homology to extracellular serine proteases of Stenotrophomonas maltophilia and Xanthomonas campestris was found in the course of a metagenome screening for detergent proteases (Niehaus et al., submitted for publication). Attempts to efficiently express the enzyme in common expression hosts had failed. This study reports on the realization of overexpression in Escherichia coli after structural modification of HP70. Modelling of HP70 resulted in a two-domain structure, comprising the catalytic domain and a C-terminal domain which includes about 100 amino acids. On the basis of the modelled structure the enzyme was truncated by deletion of most of the C-terminal domain yielding HP70-C477.
This structural modification allowed effective expression of active enzyme using E. coli BL21-Gold as the host. Specific activity of HP70-C477 determined with suc-l-Ala-l-Ala-l-Pro-l-Phe-p-nitroanilide as the substrate was 30 ± 5 U/mg compared to 8 ± 1 U/mg of the native enzyme. HP70-C477 was most active at 40 °C and pH 7–11; these conditions are prerequisite for a potential application as detergent enzyme. Determination of kinetic parameters at 40 °C and pH = 9.5 resulted in KM = 0.23 ± 0.01 mM and kcat = 167.5 ± 3.6 s⁻¹. MS-analysis of peptide fragments obtained from incubation of HP70 and HP70-C477 with insulin B indicated that the C-terminal domain influences the cleavage preferences of the enzyme. Washing experiments confirmed the high potential of HP70-C477 as detergent protease.
Die SPAC-SE ist börsenfähig und damit eine für eine SPAC grundsätzlich geeignete Rechtsform. Die Tatsache, dass es sich hierbei (zunächst) um eine leere, arbeitnehmerlose Hülle handelt, ändert hieran nichts. Die Gründung einer solchen Vorrats-SE ist trotz fehlender Arbeitnehmerbeteiligung unter teleologischer Reduktion von Art. 12 II SE-VO zulässig. Im Gegenzug muss die Arbeitnehmerbeteiligung gemaß § 18 III SEBG analog nachgeholt werden, wenn das später erworbene Zielunternehmen auf die SPAC-SE verschmolzen werden soll. Aus gesellschaftsrechtlicher Sicht ist zu beachten, dass die SPAC-SE mit Sitz in Deutschland, welche auch den deutschen, aktienrechtlichen Bestimmungen unterliegt, nur bedingt für eine SPAC geeignet erscheint. Das deutsche Aktienrecht enthält strenge Regelungen, die der für eine SPAC-SE erforderlichen Flexibilität entgegenstehen können. Dies gilt insbesondere für das Erfordernis der Zustimmung der Hauptversammlung zur Akquisition des Zielunternehmens, die Rückzahlung des Treuhandvermögens an Aktionäre, die der Akquisition nicht zugestimmt haben und die Liquidation der SPAC-SE im Falle des Scheiterns des Erwerbs des Zielobjektes.
In den letzten drei bis vier Jahren unterlag der Bereich der Bilanzierung und Offenlegung von unsicheren Steuerpositionen im IFRS- und US-GAAP-Abschluss einem stetigen Wandel. Sowohl nach US-GAAP als auch nach IFRS nehmen die Anforderungen an die Bilanzierung und Offenlegung beständig zu. Schon allein dies zeigt die Bedeutung, die dem Themenbereich der Steuerrisiken beigemessen wird. Aber nicht nur im Rahmen der Berichterstattung im Jahresabschluss stehen Steuerrisiken oben auf der Agenda, auch der amerikanische Internal Revenue Service (IRS) verfolgt das Thema sehr konsequent und plant, bestimmte Unternehmen zu Angaben von Steuerrisiken im Rahmen der Steuererklärungen zu verpflichten.
Der Aufsatz befasst sich mit den neueren Entwicklungen im Bereich der Bilanzierung und Offenlegung von unsicheren Steuerpositionen in der Rechnungslegung nach IFRS, US-GAAP und HGB und der Offenlegung von Steuerrisiken im Rahmen der Steuererklärung.
Betriebsratswahlen 2010
(2010)
Die nächsten regelmäßigen Wahlen zum Betriebsrat (BR) stehen vor der Tür. Sie finden in der Zeit vom 1.3.2010 bis 31.5.2010 statt. Die Wahlen sind zwar vornehmlich Sache der Arbeitnehmer, allerdings sollten auch die Arbeitgeber darauf achten, dass die Wahlen korrekt ablaufen, schließlich haben die Arbeitgeber die Kosten der Wahlen zu tragen. Kommt es hierbei zu Fehlern, die schlimmstenfalls eine Wiederholung der Wahlen erfordern, hat auch für die hierdurch zusätzlich entstehenden Kosten der Arbeitgeber aufzukommen. Zudem bietet die aktive und unterstützende Begleitung der Wahlen für die Arbeitgeber die Chance, die Grundlagen für eine konstruktive Zusammenarbeit mit dem künftigen Betriebsrat zu legen. Der vorliegende Beitrag erläutert die wesentlichen Abläufe des Wahlverfahrens sowie die hierbei zwingend zu beachtenden Fristen.
Die Spritzbetonbauweise hat sich im Tunnelbau seit Jahren bewährt. Spritzbeton wird als unbewehrter Beton, in Verbindung mit Bewehrung sowie als Stahlfaserspritzbeton eingesetzt. Bei den meisten Tunnelschalen aus Stahlfaserspritzbeton werden Stahlfasern derzeit nur als konstruktive Bewehrung verwendet. Die Faserzugabe führt zu einer nennenswerten Erhöhung der Bruchenergie und somit zu einer höheren Zähigkeit des sonst spröden Materials und damit zu einer höheren Sicherheit.
Stahlfaserspritzbeton kann auch anstelle von Spritzbeton mit statisch erforderlicher Mattenbewehrung eingesetzt werden. Die Bemessung erfolgt dann unter Berücksichtigung der Nachrisszugfestigkeit. Diese kann wie bei Stahlfaserbeton an Biegebalken ermittelt werden, die aus größeren Proben herausgesägt werden. Anhand von verschiedenen Beispielen werden die unterschiedlichen Anwendungen aufgezeigt und die dafür erforderlichen Prüfungen vorgestellt.
Two- and three-dimensional avalanche dynamics models are being increasingly used in hazard-mitigation studies. These models can provide improved and more accurate results for hazard mapping than the simple one-dimensional models presently used in practice. However, two- and three-dimensional models generate an extensive amount of output data, making the interpretation of simulation results more difficult. To perform a simulation in three-dimensional terrain, numerical models require a digital elevation model, specification of avalanche release areas (spatial extent and volume), selection of solution methods, finding an adequate calculation resolution and, finally, the choice of friction parameters. In this paper, the importance and difficulty of correctly setting up and analysing the results of a numerical avalanche dynamics simulation is discussed. We apply the two-dimensional simulation program RAMMS to the 1968 extreme avalanche event In den Arelen. We show the effect of model input variations on simulation results and the dangers and complexities in their interpretation.
Eine SPS im Kraftfahrzeug? Das geht ja gar nicht – da gibt es doch all die Hersteller für Kfz-Steuergeräte, die konfigurierbare Hardware anbieten. Im Prinzip ja, aber leider sind gerade die Sensoren oder Aktoren nicht ansteuerbar, die der Entwickler genau für sein aktuelles Projekt benötigt. Dieser Beitrag gibt einen kleinen Einblick in neue Möglichkeiten des Rapid Prototyping für mechatronische Systeme auf der Basis von Speicherprogrammierbaren Steuerungen (SPS).
The control of molecular architecture provided by the layer-by-layer (LbL) technique has led to enhanced biosensors, in which advantageous features of distinct materials can be combined. Full optimization of biosensing performance, however, is only reached if the film morphology is suitable for the principle of detection of a specific biosensor. In this paper, we report a detailed morphology analysis of LbL films made with alternating layers of single-walled carbon nanotubes (SWNTs) and polyamidoamine (PAMAM) dendrimers, which were then covered with a layer of penicillinase (PEN). An optimized performance to detect penicillin G was obtained with 6-bilayer SWNT/PAMAM LbL films deposited on p-Si-SiO2-Ta2O5 chips, used in biosensors based on a capacitive electrolyte-insulator-semiconductor (EIS) and a light-addressable potentiometric sensor (LAPS) structure, respectively. Field-emission scanning electron microscopy (FESEM) and atomic force microscopy (AFM) images indicated that the LbL films were porous, with a large surface area due to interconnection of SWNT into PAMAM layers. This morphology was instrumental for the adsorption of a larger quantity of PEN, with the resulting LbL film being highly stable. The experiments to detect penicillin were performed with constant-capacitance (ConCap) and constant-current (CC) measurements for EIS and LAPS sensors, respectively, which revealed an enhanced detection signal and sensitivity of ca. 100 mV/decade for the field-effect sensors modified with the PAMAM/SWNT LbL film. It is concluded that controlling film morphology is essential for an enhanced performance of biosensors, not only in terms of sensitivity but also stability and response time.
Purpose:
MRI plays a leading diagnostic role in assessing the musculoskeletal (MSK) system and is well established for most questions at clinically used field strengths (up to 3 T). However, there are still limitations in imaging early stages of cartilage degeneration, very fine tendons and ligaments, or in locating nerve lesions, for example. 7 T MRI of the knee has already received increasing attention in the current published literature, but there is a strong need to develop new radiofrequency (RF) coils to assess more regions of the MSK system. In this work, an eight-channel transmit/receive RF array was built as a multipurpose coil for imaging some of the thus far neglected regions. An extensive coil characterization protocol and first in vivo results of the human wrist, shoulder, elbow, knee, and ankle imaged at 7 T will be presented.
Methods:
Eight surface loop coils with a dimension ofurn:x-wiley:00942405:media:mp7176:mp7176-math-0001 were machined from FR4 circuit board material. To facilitate easy positioning, two coil clusters, each with four loop elements, were combined to one RF transmit/receive array. An overlapped and shifted arrangement of the coil elements was chosen to reduce the mutual inductance between neighboring coils. A phantom made of body-simulating liquid was used for tuning and matching on the bench. Afterward, the S-parameters were verified on a human wrist, elbow, and shoulder. For safety validation, a detailed compliance test was performed including full wave simulations of the RF field distribution and the corresponding specific absorption rate (SAR) for all joints. In vivo images of four volunteers were assessed with gradient echo and spin echo sequences modified to obtain optimal image contrast, full anatomic coverage, and the highest spatial resolution within a reasonable acquisition time. The performance of the RF coil was additionally evaluated by in vivo B1 mapping.
Results:
A comparison of B1 per unit power, flip angle distribution, and anatomic images showed a fairly homogeneous excitation for the smaller joints (elbow, wrist, and ankle), while for the larger joints, the shoulder and especially the knee, B1 inhomogeneities and limited penetration depth were more pronounced. However, the greater part of the shoulder joint could be imaged.In vivo images rendered very fine anatomic details such as fascicles of the median nerve and the branching of the nerve bundles. High-resolution images of cartilage, labrum, and tendons could be acquired. Additionally, turbo spin echo (TSE) and inversion recovery sequences performed very well.
Conclusions:
This study demonstrates that the concept of two four-channel transmit/receive RF arrays can be used as a multipurpose coil for high-resolutionin vivo MR imaging of the musculoskeletal system at 7 T. Not only gradient echo but also typical clinical and SAR-intensive sequences such as STIR and TSE performed well. Imaging of small structures and peripheral nerves could in particular benefit from this technique.
Der folgende Bericht fasst Erfahrungen zusammen, die in großen Entwicklungsprojekten der Firma Ericsson über mehrere Jahre gesammelt wurden. Ziel war dabei nicht, agile Methoden und Techniken einzusetzen - Agilität war zu der Zeit noch kein Hype-Thema. Vielmehr wurden Schwächen in den eigenen Projekten identifiziert und verbessert. Der Erfahrungsbericht vergleicht Verbesserungen in diesen Projekten mit den Ansätzen der agilen Entwicklung. Als Ergebnis werden folgende Punkte festgehalten: Erstens, einige Praktiken und Werte der agilen Entwicklung lassen sich auch in Großprojekten einsetzen. Zweitens, bei der Skalierung für Großprojekte werden diese Praktiken langsamer getaktet. Drittens, agile Entwicklung ist nicht nur eine Reihe von Praktiken und Werten, agile Entwicklung ist vielmehr auch eine Frage der Entwicklungs- und Projektkultur. Diese kulturelle Änderung lässt sich in Großprojekten deutlich langsamer umsetzen.
Additive Manufacturing of metal parts by Selective Laser Melting has become a powerful tool for the direct manufacturing of complex parts mainly for the aerospace and medical industry. With the introduction of its desktop machine, Realizer targeted the dental market. The contribution describes the special features of the machine, discusses details of the process and shows manufacturing results focused on metal dental devices.
Background
To demonstrate the applicability of acoustic cardiac triggering (ACT) for imaging of the heart at ultrahigh magnetic fields (7.0 T) by comparing phonocardiogram, conventional vector electrocardiogram (ECG) and traditional pulse oximetry (POX) triggered 2D CINE acquisitions together with (i) a qualitative image quality analysis, (ii) an assessment of the left ventricular function parameter and (iii) an examination of trigger reliability and trigger detection variance derived from the signal waveforms.
Results
ECG was susceptible to severe distortions at 7.0 T. POX and ACT provided waveforms free of interferences from electromagnetic fields or from magneto-hydrodynamic effects. Frequent R-wave mis-registration occurred in ECG-triggered acquisitions with a failure rate of up to 30% resulting in cardiac motion induced artifacts. ACT and POX triggering produced images free of cardiac motion artefacts. ECG showed a severe jitter in the R-wave detection. POX also showed a trigger jitter of approximately Δt = 72 ms which is equivalent to two cardiac phases. ACT showed a jitter of approximately Δt = 5 ms only. ECG waveforms revealed a standard deviation for the cardiac trigger offset larger than that observed for ACT or POX waveforms.
Image quality assessment showed that ACT substantially improved image quality as compared to ECG (image quality score at end-diastole: ECG = 1.7 ± 0.5, ACT = 2.4 ± 0.5, p = 0.04) while the comparison between ECG vs. POX gated acquisitions showed no significant differences in image quality (image quality score: ECG = 1.7 ± 0.5, POX = 2.0 ± 0.5, p = 0.34).
Conclusions
The applicability of acoustic triggering for cardiac CINE imaging at 7.0 T was demonstrated. ACT's trigger reliability and fidelity are superior to that of ECG and POX. ACT promises to be beneficial for cardiovascular magnetic resonance at ultra-high field strengths including 7.0 T.
A novel scheme for precise diagnostics and effective stabilization of currents in a fuel cell stack
(2010)
A novel scheme for detecting inhomogeneous internal currents in a fuel cell stack is presented. In this paper the scheme is investigated for the case that the flow field plates consist of graphite. Then plates of high conductivity, e.g. aluminium between the flow field plates together with small slits in these plates have three effects: (a) Whenever a local inhomogeneity of the electric current occurs at a particular cell in the stack, this will induce a surface current close to that cell perpendicular to the averaged current. This current can be detected. (b) The plates of high conductivity completely prevent the inhomogeneities from spreading to neighbouring cells. (c) Even at the particular cell the inhomogeneity is suppressed as far as possible. Thus this scheme leads to much better diagnostic possibilities and at the same time reduces electric instabilities to an extent, where they probably become harmless. This scheme will first be explained for a simple model to clarify the idea. However, very precise three dimensional computations using realistic parameters are presented, corroborating the results of the simple model.
Background: To elaborate the impact of new haemostatic agents we developed an instrument for the pressure-controlled induction of blunt liver injuries in a porcine animal model. Materials and Methods: A dilutional coagulopathy of 80% of animal blood volume was induced in 9 anaesthetized pigs. Animals were randomly assigned to be injured with a force of 112 Newton (N) (n = 1), 224 ± 19 N (n = 4) or 355 ± 35 N (n = 4). The impact of injury was measured by blood loss, survival time and coagulation parameters. Liver histology was obtained to evaluate the degree of liver injury. Results: The profound haemodilution resulted in a significant alteration of all coagulation parameters. After inflicting the injury with 355 ± 35 N, both the survival time (30 ± 9 min; p = 0.006) and blood loss (68 ± 16 ml min–1, p = 0.002) were significantly different as compared to injuries with 224 ± 19 N (survival time: 76 ± 20 min, blood loss: 23 ± 4 ml min–1). In contrast, an injury with 112 N led to an insignificant blood loss of only 239 ml. Conclusion: We developed a pressure-controlled clamp that allows for the induction of blunt liver traumas with highly reproducible injuries with a positive correlation with blood loss and survival.
This Research Briefing, issued in July 2010, concluded that:
- Small and medium-sized enterprises (SMEs) in Europe have long called for a matching legal form valid across the EU (similar to that of the European company (SE) for large firms)
- The main benefits would be the availability of uniform Europe-wide company structures, significant cost reductions for businesses and further integration of the internal market
- Given the differing national views regarding the concrete features of the new legal form there is currently no sign of an agreement being reached at the European level in the short term; however, it is possible that progress will be made in negotiations during the year
- The key issues being discussed in depth are company formation, transnationality and employee participation rights in the new European private company (SPE).