Refine
Year of publication
- 2014 (142) (remove)
Document Type
- Article (142) (remove)
Keywords
- Antarctic Glaciology (1)
- DNA hybridization (1)
- Extraterrestrial Glaciology (1)
- Field-effect sensor (1)
- Glaciological instruments and methods (1)
- LAPS (1)
- Light-addressable Potentiometric Sensor (1)
- Subclacial exploration (1)
- Subglacial lakes (1)
- SunRav BookEditor (1)
- adsorption (1)
- barium strontium titanate (1)
- bioavailability (1)
- carbonized rice husk (1)
- contactless conductivity sensor (1)
- distance learning (1)
- drug metabolising enzymes (1)
- drug–drug interactions (1)
- e-books (1)
- e-issues (1)
Institute
- Fachbereich Medizintechnik und Technomathematik (42)
- Fachbereich Chemie und Biotechnologie (25)
- INB - Institut für Nano- und Biotechnologien (25)
- Fachbereich Wirtschaftswissenschaften (19)
- Fachbereich Elektrotechnik und Informationstechnik (13)
- Fachbereich Maschinenbau und Mechatronik (13)
- Fachbereich Energietechnik (12)
- IfB - Institut für Bioengineering (12)
- Fachbereich Bauingenieurwesen (4)
- Fachbereich Luft- und Raumfahrttechnik (4)
- Fachbereich Architektur (3)
- Solar-Institut Jülich (3)
- Sonstiges (3)
- Institut fuer Angewandte Polymerchemie (1)
- ZHQ - Bereich Hochschuldidaktik und Evaluation (1)
The constitutive androstane receptor (CAR) and the pregnane X receptor (PXR) are closely related nuclear receptors involved in drug metabolism and play important roles in the mechanism of phenobarbital (PB)-induced rodent nongenotoxic hepatocarcinogenesis. Here, we have used a humanized CAR/PXR mouse model to examine potential species differences in receptor-dependent mechanisms underlying liver tissue molecular responses to PB. Early and late transcriptomic responses to sustained PB exposure were investigated in liver tissue from double knock-out CAR and PXR (CARᴷᴼ-PXRᴷᴼ), double humanized CAR and PXR (CARʰ-PXRʰ), and wild-type C57BL/6 mice. Wild-type and CARʰ-PXRʰ mouse livers exhibited temporally and quantitatively similar transcriptional responses during 91 days of PB exposure including the sustained induction of the xenobiotic response gene Cyp2b10, the Wnt signaling inhibitor Wisp1, and noncoding RNA biomarkers from the Dlk1-Dio3 locus. Transient induction of DNA replication (Hells, Mcm6, and Esco2) and mitotic genes (Ccnb2, Cdc20, and Cdk1) and the proliferation-related nuclear antigen Mki67 were observed with peak expression occurring between 1 and 7 days PB exposure. All these transcriptional responses were absent in CARᴷᴼ-PXRᴷᴼ mouse livers and largely reversible in wild-type and CARʰ-PXRʰ mouse livers following 91 days of PB exposure and a subsequent 4-week recovery period. Furthermore, PB-mediated upregulation of the noncoding RNA Meg3, which has recently been associated with cellular pluripotency, exhibited a similar dose response and perivenous hepatocyte-specific localization in both wild-type and CARʰ-PXRʰ mice. Thus, mouse livers coexpressing human CAR and PXR support both the xenobiotic metabolizing and the proliferative transcriptional responses following exposure to PB.
Vor dem Hintergrund zunehmender gesellschaftlicher Veränderungen bei den Lebens- und Familienformen hat es sich die Commission on European Family Law (CEFL) seit 2001 zum Ziel gesetzt, unverbindliche Regelungsvorschläge für ein europaweit einheitliches Familienrecht zu schaffen. Die Vorstellung und Diskussion dieser auf rechtsvergleichender Basis erstellten Principles erfolgt auf den regelmäßig veranstalteten Tagungen der CEFL. Die nunmehr fünfte Konferenz zum Thema „Family Law and Culture in Europe – Developments, Challenges and Opportunities“ fand erstmals in Deutschland statt. Ausgerichtet wurde die Veranstaltung, zu der ca. 200 Teilnehmerinnen und Teilnehmern aus Wissenschaft und Praxis aus insgesamt 33 Ländern angereist waren, von Nina Dethloff (Direktorin des Instituts für Deutsches, Europäisches und Internationales Familienrecht an der Universität Bonn), Katharina Boele-Woelki (Direktorin des Utrecht Centre for European Research into Family Law und Preisträgerin des Anneliese Maier-Forschungspreises der Alexander von Humboldt-Stiftung) und Werner Gephart (Direktor des Käte Hamburger Kollegs „Recht als Kultur“).
Does stiffer electoral competition reduce political shirking? For a micro-analysis of this question, I construct a new data set spanning the years 2005 to 2012 covering biographical and political information about German Members of Parliament (MPs), including their attendance rates in voting sessions. For the parliament elected in 2009, I show that indeed opposition party MPs who expect to face a close race in their district show significantly and relevantly lower absence rates in parliament beforehand. MPs of governing parties seem not to react significantly to electoral competition. These results are confirmed by an analysis of the parliament elected in 2005, by several robustness checks, and also by employing an instrumental variable strategy exploiting convenient peculiarities of the German electoral system. The study also shows how MPs elected via party lists react to different levels of electoral competition.
This paper investigates the extent to which corporate governance affects the cost of debt and equity capital of German exchange-listed companies. I examine corporate governance along three dimensions: financial information quality, ownership structure and board structure. The results suggest that firms with high levels of financial transparency and bonus compensations face lower cost of equity. In addition, block ownership is negatively related to firms' cost of equity when the blockholders are other firms, managers or founding-family members. Consistent with the conjecture that agency costs increase with firm size, I find significant cost of debt effects only in the largest German companies. Here, the creditors demand lower cost of debt from firms with block ownerships held by corporations or banks. My findings demonstrate that a uniform set of governance attributes is unlikely to satisfy suppliers of debt and equity capital equally.
Ab dem 1.1.2015 ist es soweit: Deutschland erhält einen flächendeckenden und weitgehend branchenunabhängigen gesetzlichen Mindestlohn. Danach haben grundsätzlich alle abhängig beschäftigten Arbeitnehmer einen Anspruch auf eine Entlohnung von wenigstens 8,50 EUR brutto je Arbeitsstunde. Die Auswirkungen dürften enorm sein. Das Bundesministerium für Arbeit und Soziales geht jedenfalls davon aus, dass aufgrund der Einführung des gesetzlichen Mindestlohns mehrere Millionen Beschäftigte einen höheren Lohn beanspruchen können. Der nachfolgende Beitrag gibt einen Überblick über die wesentlichen Inhalte des gesetzlichen Mindestlohns und Hinweise für Anwendungsprobleme in der betrieblichen Praxis.
Die Beschäftigung von Prokuristen ist gängige betriebliche Praxis. Unternehmen stehen dabei immer wieder vor der Frage, ob und welche Arbeitnehmer sie zu Prokuristen bestellen sollen. Nicht selten bleiben hierbei die arbeitsrechtlichen Konsequenzen, die mit der Bestellung eines Arbeitnehmers zum Prokuristen einhergehen können, unberücksichtigt, wie diverse Gerichtsentscheidungen zeigen. Dieser Beitrag soll einen Überblick über die arbeitsrechtlichen Folgen bei der Beschäftigung von Prokuristen geben und der betrieblichen Praxis somit gleichzeitig als Entscheidungshilfe dienen, wenn es um das Ob und Wie der möglichen Bestellung eines Arbeitnehmers zum Prokuristen geht.
Network theory provides novel concepts that promise an improved characterization of interacting dynamical systems. Within this framework, evolving networks can be considered as being composed of nodes, representing systems, and of time-varying edges, representing interactions between these systems. This approach is highly attractive to further our understanding of the physiological and pathophysiological dynamics in human brain networks. Indeed, there is growing evidence that the epileptic process can be regarded as a large-scale network phenomenon. We here review methodologies for inferring networks from empirical time series and for a characterization of these evolving networks. We summarize recent findings derived from studies that investigate human epileptic brain networks evolving on timescales ranging from few seconds to weeks. We point to possible pitfalls and open issues, and discuss future perspectives.
Gebaute Geschichte in Turin
(2014)
Access to promising radiometals as isotopes for novel molecular imaging agents requires that they are routinely available and inexpensive to obtain. Proximity to a cyclotron center outfitted with solid target hardware, or to an isotope generator for the metal of interest is necessary, both of which can introduce significant hurdles in development of less common isotopes. Herein, we describe the production of ⁴⁴Sc (t₁⸝₂ = 3.97 h, Eavg,β⁺ = 1.47 MeV, branching ratio = 94.27%) in a solution target and an automated loading system which allows a quick turn-around between different radiometallic isotopes and therefore greatly improves their availability for tracer development. Experimental yields are compared to theoretical calculations.
The development of a cost-effective hydrolysis for crude cellulose is an essential part of biorefinery developments. To establish such high solid hydrolysis, a new solid state reactor with static mixing is used. However, concentrations >10% (w/w) cause a rate and yield reduction of enzymatic hydrolysis. By optimizing the synergetic activity of cellulolytic enzymes at solid concentrations of 9%, 17% and 23% (w/w) of crude Organosolv cellulose, glucose concentrations of 57, 113 and 152 g L⁻¹ are reached. However, the glucose yield decreases from 0.81 to 0.72gg⁻¹ at 17% (w/w). Optimal conditions for hydrolysis scale-up under minimal enzyme addition are identified. As result, at 23% (w/w) crude cellulose the glucose yield increases from 0.29 to 0.49gg⁻¹. As proof of its applicability, biobutanol, succinic and itaconic acid are produced with the crude hydrolysate. The potential of the substrate is proven e.g. by a high butanol yield of 0.33gg⁻¹.
Biotechnologie und die mit ihr verbundenen technischen Prozesse prägen seit Jahrtausenden die Entwicklung der Menschheit. Ausgehend von empirischen Verfahren, insbesondere zur Herstellung von Lebensmitteln und täglichen Gebrauchsgütern, haben sich diese Disziplinen zu einem der innovativsten Zukunftsfelder entwickelt. Durch das immer detailliertere Verständnis zellulärer Vorgänge können mittlerweile Produktionsstämme gezielt optimiert werden. Im Zusammenspiel mit moderner Prozesstechnik können so eine Vielzahl von Bulk- und Feinchemikalien sowie Pharmazeutika effizient hergestellt werden. In diesem Artikel werden exemplarisch einige der aktuellen Trends vorgestellt.
Adsorptive Vorbehandlung von Rohglycerin für die 1,3-Propandiol Fermentation mit Clostridium diolis
(2014)
Bei der Gewinnung von Fettsäuren aus Pflanzenölen, z. B. zur Herstellung von Biopolymeren, oder bei der Biodiesel- und Seifenproduktion, fällt Glycerin als Nebenprodukt an. Bei der Biokonversion dieses Rohstoffes zu 1,3-Propandiol wird der Produktionsorganismus Clostridium diolis durch Verunreinigungen im Rohglycerin gehemmt. Als inhibierende Substanzen konnten freie Fettsäuren identifiziert werden. Mithilfe eines adsorptiven Aufarbeitungsverfahrens ist es gelungen, die Fettsäuren zu entfernen und die Konversionseffizienz zu 1,3-Propandiol zu erhöhen.
A major part of edible oil is subjected to bleaching procedures, primarily with minerals applied as adsorbers. Their recycling is currently done either by regaining the oil via organic solvent extraction or by using the spent bleaching earth (SBE) as additive for animal feed, etc. As a new method, the reutilization of the by-product SBE for the microbiologic formation of acetone, butanol, and ethanol (ABE) is presented as proof-of-concept. The SBE was taken from a palm oil cleaning process. The recycling concept is based on the application of lipolytic clostridia strains. Due to considerably long fermentation times, co-fermentation with Candida rugosa and enzymatic hydrolyses of the bound oil with a subsequent clostridia fermentation are shown as alternative routes. Anaerobic fermentations under comparison of different clostridia strains were performed with glycerol media, enzymatically hydrolyzed palm oil and SBE. Solutes, side product compositions and productivities were quantified via HPLC. A successful production of ABE solutes from SBE has been done with a yield of 0.15 g butanol per gram of bound glycerol. Thus, the biotechnological recycling of the waste stream is possible in principle. Inhibition of the substrate suspension has been observed. A chromatographic ion-exchange of substrates increased the biomass concentration.
High gradient magnetic separation (HGMS) has been established since the early 1970s. A more recent application of these systems is the use in bioprocesses. To integrate the HGMS in a fermentation process, it is necessary to optimize the separation matrix with regard to the magnetic separation characteristics and permeability of the non-magnetizable components of the fermentation broth. As part of the work presented here, a combined fluidic and magnetic force finite element model simulation was created using the software COMSOL Multiphysics and compared with separation experiments. Finally, as optimal lattice orientation of the separation matrix, a transversal rhombohedral arrangement was defined. The high suitability of the new filter matrix has been verified by separation experiments.
Purpose
To demonstrate that high quality T₂-weighted (T2w) turbo spin-echo (TSE) imaging of the complete prostate can be achieved routinely and within safety limits at 7 T, using an external transceive body array coil only.
Methods
Nine healthy volunteers and 12 prostate cancer patients were scanned on a 7 T whole-body system. Preparation consisted of B₀ and radiofrequency shimming and localized flip angle calibration. T₁ and T₂ relaxation times were measured and used to define the T2w-TSE protocol. T2w imaging was performed using a TSE sequence (pulse repetition time/echo time 3000–3640/71 ms) with prolonged excitation and refocusing pulses to reduce specific absorption rate.
Results
High quality T2w TSE imaging was performed in less than 2 min in all subjects. Tumors of patients with gold-standard tumor localization (MR-guided biopsy or prostatectomy) were well visualized on 7 T imaging (n = 3). The number of consecutive slices achievable within a 10-g averaged specific absorption rate limit of 10 W/kg was ≥28 in all subjects, sufficient for full prostate coverage with 3-mm slices in at least one direction.
Conclusion
High quality T2w TSE prostate imaging can be performed routinely and within specific absorption rate limits at 7 T with an external transceive body array.
Objectives
The aim of this study was to identify characteristics of phosphorus (³¹P) spectra of the human prostate and to investigate changes of individual phospholipid metabolites in prostate cancer through in vivo ³¹P magnetic resonance spectroscopic imaging (MRSI) at 7 T.
Materials and Methods
In this institutional review board–approved study, 15 patients with biopsy-proven prostate cancer underwent T₂-weighted magnetic resonance imaging and 3-dimensional ³¹P MRSI at 7 T. Voxels were selected at the tumor location, in normal-appearing peripheral zone tissue, normal-appearing transition zone tissue, and in the base of the prostate close to the seminal vesicles. Phosphorus metabolite ratios were determined and compared between tissue types.
Results
Signals of phosphoethanolamine (PE) and phosphocholine (PC) were present and well resolved in most ³¹P spectra in the prostate. Glycerophosphocholine signals were observable in 43% of the voxels in malignant tissue, but in only 10% of the voxels in normal-appearing tissue away from the seminal vesicles. In many spectra, independent of tissue type, 2 peaks resonated in the chemical shift range of inorganic phosphate, possibly representing 2 separate pH compartments. The PC/PE ratio in the seminal vesicles was highly elevated compared with the prostate in 5 patients. A considerable overlap of ³¹P metabolite ratios was found between prostate cancer and normal-appearing prostate tissue, preventing direct discrimination of these tissues. The only 2 patients with high Gleason scores tumors (≥4+5) presented with high PC and glycerophosphocholine levels in their cancer lesions.
Conclusions
Phosphorus MRSI at 7 T shows distinct features of phospholipid metabolites in the prostate gland and its surrounding structures. In this exploratory study, no differences in ³¹P metabolite ratios were observed between prostate cancer and normal-appearing prostate tissue possibly because of the partial volume effects of small tumor foci in large MRSI voxels.