Tidal dynamics control on cold-water coral growth: A high-resolution multivariable study on eastern Atlantic cold-water coral sites

Cold-water coral communities form complex benthic ecosystems in a distinct part of the water column. The exact processes supporting reef growth and changes with time are still partly unsolved. Recent studies have suggested a tidally driven hydraulic control of flow over topographic features as a driver for local downwelling at cold-water coral sites. This mechanism forms a link between surface and coral growth depths and is a driver of resuspension of the bottom material. Only few studies have concentrated on how these processes vary with the health status and structure of the cold-water coral occurrences. In this study, we explore the processes over tidal cycles by analysing in situ stratification, hydrography and velocity data which we then combine with local topography from seven Lophelia pertusa dominated eastern Atlantic cold-water coral sites. The “quality” of coral sites varies from thriving reefs to declining and dead coral sites. We show that living and healthy corals are concentrated at sites, where local hydrodynamics create overturning and mixing which support food supply for filter-feeding corals

Current Redistribution in a Superconducting Multi-Strand 35 kA DC Cable Demonstrator

High temperature superconductors (HTS) are discussed as energy-efficient solutions for industrial high-current applications beyond 10 kA e.g., bus bar systems in industrial electrolysis plants. In this contribution, the experimental test of a 3.6-meter-long 35 kA DC demonstrator, made from twelve high-current HTS CrossConductor (HTS CroCo) strands in an liquid nitrogen bath at T = 77 K is presented. In this work, a common connector concept of the twelve HTS CroCo strands is proposed. Compared to earlier results without common connector, lead resistances were effectively reduced and current distribution among the individual strands was significantly facilitated. This is confirmed by the observation of increased critical cable current of 37.6 kA compared to 33 kA in previous work without low-resistive common connector. Additionally, the current range, in which all twelve strands reached their critical electric field, was found to be reduced from >7 kA to 2 kA. Results are discussed and assessed with the help of an electric circuit model, from which the solder resistances at the connections could be obtained by fitting. Particular focus was given to the investigation of current redistribution in the demonstrator. Therefore, a heater was installed on one HTS CroCo strand, and activated to raise the temperature on this strand and quench a single strand locally. It is observed that current is redistributed through the common connectors to the other strands

Assessment of liver fibrosis and associated risk factors in HIV-infected individuals using transient elastography and serum biomarkers

Background: Liver fibrosis in human immunodeficiency virus (HIV)-infected individuals is mostly attributable to co-infection with hepatitis B or C. The impact of other risk factors, including prolonged exposure to combined antiretroviral therapy (cART) is poorly understood. Our aim was to determine the prevalence of liver fibrosis and associated risk factors in HIV-infected individuals based on non-invasive fibrosis assessment using transient elastography (TE) and serum biomarkers (Fibrotest [FT]). Methods: In 202 consecutive HIV-infected individuals (159 men; mean age 47 ± 9 years; 35 with hepatitis-C-virus [HCV] co-infection), TE and FT were performed. Repeat TE examinations were conducted 1 and 2 years after study inclusion. Results: Significant liver fibrosis was present in 16% and 29% of patients, respectively, when assessed by TE (≥ 7.1 kPa) and FT (> 0.48). A combination of TE and FT predicted significant fibrosis in 8% of all patients (31% in HIV/HCV co-infected and 3% in HIV mono-infected individuals). Chronic ALT, AST and γ-GT elevation was present in 29%, 20% and 51% of all cART-exposed patients and in 19%, 8% and 45.5% of HIV mono-infected individuals. Overall, factors independently associated with significant fibrosis as assessed by TE (OR, 95% CI) were co-infection with HCV (7.29, 1.95-27.34), chronic AST (6.58, 1.30-33.25) and γ-GT (5.17, 1.56-17.08) elevation and time on dideoxynucleoside therapy (1.01, 1.00-1.02). In 68 HIV mono-infected individuals who had repeat TE examinations, TE values did not differ significantly during a median follow-up time of 24 months (median intra-patient changes at last TE examination relative to baseline: -0.2 kPa, p = 0.20). Conclusions: Chronic elevation of liver enzymes was observed in up to 45.5% of HIV mono-infected patients on cART. However, only a small subset had significant fibrosis as predicted by TE and FT. There was no evidence for fibrosis progression during follow-up TE examinations

Baseline MELD score predicts hepatic decompensation during antiviral therapy in patients with chronic hepatitis C and advanced cirrhosis

Background and Aims: In patients with advanced liver cirrhosis due to chronic hepatitis C virus (HCV) infection antiviral therapy with peginterferon and ribavirin is feasible in selected cases only due to potentially life-threatening side effects. However, predictive factors associated with hepatic decompensation during antiviral therapy are poorly defined. Methods: In a retrospective cohort study, 68 patients with HCV-associated liver cirrhosis (mean MELD score 9.18±2.72) were treated with peginterferon and ribavirin. Clinical events indicating hepatic decompensation (onset of ascites, hepatic encephalopathy, upper gastrointestinal bleeding, hospitalization) as well as laboratory data were recorded at baseline and during a follow up period of 72 weeks after initiation of antiviral therapy. To monitor long term sequelae of end stage liver disease an extended follow up for HCC development, transplantation and death was applied (240weeks, ±SD 136weeks). Results: Eighteen patients (26.5%) achieved a sustained virologic response. During the observational period a hepatic decompensation was observed in 36.8%. Patients with hepatic decompensation had higher MELD scores (10.84 vs. 8.23, p14, respectively. Baseline MELD score was significantly associated with the risk for transplantation/death (p<0.001). Conclusions: Our data suggest that the baseline MELD score predicts the risk of hepatic decompensation during antiviral therapy and thus contributes to decision making when antiviral therapy is discussed in HCV patients with advanced liver cirrhosis

Ein modulares multidisziplinäres Meeresboden-Observatorium : MoLab ; Abschlußbericht ; Laufzeit: 1.5.2010 - 31.12.2010

Research on global change and sustainable use of marine resources requires new scientific and technological concepts based on a synoptic, spatial and time synchronized measurement of key environmental parameters. A modular multidisciplinary 4D-longterm observatory (MoLab) as contribution to this complex was designed and purchased. MoLab measures physical and biogeochemical processes in the benthic boundary layer. The modular MoLab system enables us to take up the technological challenge for highly resolved spatially and timely synchronized measurements of the complex interactions of biological, physical, chemical and geological processes in meso-scale dimensions. Molab comprises of an array of individual modules which can be arranged and composed in a flexible response to the scientific mission. The MoLab array is composed of several lander systems of different size and equipment and of oceanographic moorings. All modules carry an identical basic sensor package. The specific feature of the MoLab system is the acoustic interconnection of the modules and sensor packages. The MoLab hart core is a central communication modul, typically integrated into a mooring, which is connected to all modules of the MoLab array via an acoustic telemetry system. This is the basis for a coherent and timely synchronized data measurement. The MoLab modular concept enables us to carry out varying process studies on varying spatial and time scales in synchronized 4D-observations. This concept will lead to a more comprehensive understanding of processes as a basis for an overriding modeling in contrast to results based on the still prevailing individual snapshot observations

rac-(2R,3S)-2-Phenyl-3-(3-phenyl-1,2,3,4-tetra­hydro­quinoxalin-2-yl)quinoxaline

The title compound, C28H22N4, is the unexpected by-product of the reaction of 2-hydroxy­acetophenone and 1,2-diamino­benzene under iodine catalysis, during which a carbon–carbon σ-bond between two quinoxaline units was formed. Although a fully oxidized title compound should sterically be possible, only one quinoxaline ring is fully oxidized while the second ring remains in the reduced form. As expected, the tetra­hydro­quinoxaline unit is not planar; it adopts a sofa conformation, whereby the atom joining the two heterocyclic systems lies out of the plane of the other atoms. The quinoxaline ring system makes a dihedral angle of 53.61 (4)° with its phenyl ring substituent. The crystal packing is determined by pairs of N—H⋯N, N—H⋯π and weak C—H⋯N hydrogen bonds, forming a chain parallel to the a axis

Development of a uniform, very aggressive disease phenotype in all homozygous carriers of the NOD2 mutation p.Leu1007fsX1008 with Crohn's disease and active smoking status resulting in ileal stenosis requiring surgery

Background: NOD2variants are the strongest genetic predictors for susceptibility to Crohn's disease (CD). However, the clinical value ofNOD2on an individual patient level remains controversial. We aimed to define the predictive power of the majorNOD2mutations regarding complicated CD in a large single center cohort. Methods 1076 CD patients were prospectively genotyped for the three common CD-associatedNOD2mutations rs2066844, rs2066845, and rs2066847, followed by detailed genotype-phenotype analyses. Results Overall, 434 CD patients (40.3%) carried at least one of the three mainNOD2mutations. A significantly higher minor allele frequency (15.6%) of theNOD2frameshift mutation p.Leu1007fsX1008 (rs2066847) was seen in patients with aggressive disease compared to 8.2% in patients with mild disease (p = 2.6 x 10(-5)). Moreover, a total of 54 CD patients (5.0%) were homozygous for thisNOD2frameshift mutation. 100% of these patients had ileal disease compared to 82% ofNOD2wild-type carriers (p<0.0001). In homozygous carriers of theNOD2frameshift mutation, 87% presented with ileal stenosis, 68.5% had fistulas, and 72.2% required CD-related surgery despite immunosuppressive therapy in 87% of these patients. All homozygous carriers of the 1007fs mutation who were active smokers had ileal stenosis and required CD-related surgery. Conclusion Homozygosity for Leu1007fsX1008 is an excellent biomarker for predicting complicated CD on an individual patient level. Active smoking and homozygosity for this mutation is associated with a 100% risk for developing ileal stenosis requiring CD-related surgery. In these patients, smoking cessation and early initiation of immunosuppressive strategies may be beneficial

Dysfunctional long-range coordination of neural activity during Gestalt perception in schizophrenia

Recent theoretical and empirical research on schizophrenia converges on the notion that core aspects of the pathophysiology of the disorder may arise from a dysfunction in the coordination of distributed neural activity. Synchronization of neural responses in the β-band (15–30 Hz) and γ-band range (30–80 Hz) has been implicated as a possible neural substrate for dysfunctional coordination in schizophrenia. To test this hypothesis, we examined the electroencephalography (EEG) activity in 19 patients with a Diagnostic and Statistical Manual of Mental Disorder, edition IV criteria, diagnosis of schizophrenia and 19 healthy control subjects during a Gestalt perception task. EEG data were analyzed for phase synchrony and induced spectral power as an index of neural synchronization. Schizophrenia patients were impaired significantly in the detection of images that required the grouping of stimulus elements into coherent object representations. This deficit was accompanied by longer reaction times in schizophrenia patients. Deficits in Gestalt perception in schizophrenia patients were associated with reduced phase synchrony in the β-band (20 –30 Hz), whereas induced spectral power in the γ-band (40 –70 Hz) was mainly intact. Our findings suggest that schizophrenia patients are impaired in the long-range synchronization of neural responses, which may reflect a core deficit in the coordination of neural activity and underlie the specific cognitive dysfunctions associated with the disorder

Festschrift anläßlich der Emeritierung von Prof. Dr.-Ing. Walter Raab

Festschrift zum Festkolloquium am 8. April 1994 anläßlich der Emeritierung von Herrn Prof. Dr.-Ing. Walter Raab, Leiter des Fachgebiets Maschinenlemente und Mechanik an der Technischen Hochschule Darmstadt