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Search Results: 1 - 10 of 4593 matches for " Erik Haverkamp "
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Broadband and omnidirectional anti-reflection layer for III/V multi-junction solar cells
Silke L. Diedenhofen,Grzegorz Grzela,Erik Haverkamp,Gerard Bauhuis,John Schermer,Jaime Gómez Rivas
Physics , 2012, DOI: 10.1016/j.solmat.2012.02.022
Abstract: We report a novel graded refractive index antireflection coating for III/V quadruple solar cells based on bottom-up grown tapered GaP nanowires. We have calculated the photocurrent density of an InGaP-GaAs-InGaAsP-InGaAs solar cell with a MgF2/ZnS double layer antireflection coating and with a graded refractive index coating. The photocurrent density can be increased by 5.9 % when the solar cell is coated with a graded refractive index layer with a thickness of 1\mu m. We propose to realize such a graded refractive index layer by growing tapered GaP nanowires on III/V solar cells. For a first demonstration of the feasibility of the growth of tapered nanowires on III/V solar cells, we have grown tapered GaP nanowires on AlInP/GaAs substrates. We show experimentally that the reflection from the nanowire coated substrate is reduced and that the transmission into the substrate is increased for a broad spectral and angular range.
Inhaled salmeterol and/or fluticasone alters structure/function in a murine model of allergic airways disease
Erik P Riesenfeld, Michael J Sullivan, John A Thompson-Figueroa, Hans C Haverkamp, Lennart K Lundblad, Jason HT Bates, Charles G Irvin
Respiratory Research , 2010, DOI: 10.1186/1465-9921-11-22
Abstract: BALB/c mice were sensitized to intraperitoneal ovalbumin (OVA) followed by six daily inhalation exposures. Treatments included 9 daily nebulized administrations of fluticasone alone (6 mg/ml), salmeterol (3 mg/ml), or the combination fluticasone and salmeterol. Lung impedance was measured following methacholine inhalation challenge. Airway inflammation, epithelial injury, mucus containing cells, and collagen content were assessed 48 hours after OVA challenge. Lungs were imaged using micro-CT.Treatment of allergic airways disease with fluticasone alone or in combination with salmeterol reduced AHR to approximately naüve levels while salmeterol alone increased elastance by 39% compared to control. Fluticasone alone and fluticasone in combination with salmeterol both reduced inflammation to near naive levels. Mucin containing cells were also reduced with fluticasone and fluticasone in combination with salmeterol.Fluticasone alone and in combination with salmeterol reduces airway inflammation and remodeling, but salmeterol alone worsens AHR: and these functional changes are consistent with the concomitant changes in mucus metaplasia.There is a variety of pathological changes that are therapeutic targets in asthma [1]. Principal among these is periodic or persistent inflammation, which is the cardinal feature of allergic asthma that presumably leads to the persistent structural changes known as remodeling. Remodeling includes a spectrum of alterations including collagen deposition, epithelial thickening, goblet cell hyperplasia and smooth muscle thickening. The overall functional consequences of airway remodeling remain uncertain [2], but the consequences are generally cast as detrimental. The propensity for the distal airways of asthmatics to become plugged with mucus is a well-known hallmark of fatal asthma [3]. Mucus also likely plays an important role in the distal airway closure that underlies the AHR of allergically inflamed mice [4-6]. Mitigation of the inflammati
Haverkamp W,Breithardt G,Eckardt L,Haverkamp F
Journal für Kardiologie , 2001,
Abstract: QT-Syndrome sind durch eine im Oberfl chen-EKG nachweisbare abnorme Verl ngerung der QT-Intervall-Dauer und das spontane Auftreten ventrikul rer Tachyarrhythmien vom Typ der Torsade de Pointes (TdP) charakterisiert. Die Rhythmusst rungen führen typischerweise zu rezidivierend auftretenden Synkopen, bei Degeneration von TdP in Kammerflimmern kann ein pl tzlicher Herztod resultieren. Es ist zu unterscheiden zwischen einer kongenitalen und einer sog. erworbenen Form der Erkrankung. W hrend wir heute wissen, da es sich beim kongenitalen QT-Syndrom (Romano-Ward-Syndrom, Jervell-und-Lange-Nielsen-Syndrom) um eine genetisch bedingte Ionenkanalerkrankung handelt, sind die Mechanismen, die zu einer erworbenen abnormen, mit TdP einhergehenden QT-Verl ngerung führen, bisher weitgehend unbekannt; nur in wenigen F llen scheinen, wie bei den angeborenen Formen, Mutationen von Genen, die für Ionenkan le kodieren, zugrundezuliegen. QT-Syndrome sind zwar relativ seltene Erkrankungen, im Spannungsfeld zwischen Klinik, traditioneller und molekulargenetischer Diagnostik sowie herk mmlichen Therapieverfahren und zukünftig anstehender genspezifischer Therapie kommt ihnen jedoch Modellcharakter zu.
Vorhofflimmern-Rezidive w hrend Langzeitbehandlung mit Amiodaron: Versagen der Therapie oder unzureichende Dosierung?
Haverkamp W,Dietz R,Rolf S
Journal für Kardiologie , 2004,
Noninvasive Surrogates for Left Ventricular Filling Pressure in Patients with Valvular Heart Disease  [PDF]
Debora Brala, Thomas G. Allison, Wilhelm Haverkamp, Ingolf Schimke, Olaf Schulz
International Journal of Clinical Medicine (IJCM) , 2015, DOI: 10.4236/ijcm.2015.63025
Background: Invasive measurement of left ventricular filling pressure is the gold standard for determining diastolic dysfunction and predicting subsequent outcomes. For repetitive assessment of diastolic function during long-term management, noninvasive surrogates are used. Their reliability and reproducibility should be validated separately for different cardiovascular diseases and conditions. The aim of this study was to identify noninvasive surrogates of invasively derived left ventricular filling pressure and to relate these surrogates to outcomes (death or valve replacement) in patients with stable, asymptomatic valvular heart disease and preserved ejection fraction. Materials and Methods: In a first cohort, we investigated 54 patients who had spiroergometry, echocardiography, and left heart catheterization within a range of 100 days. In a second cohort (n = 64), noninvasive measures were related to outcomes after follow-up of 694 ± 576 days. Transmitral doppler E/tissue doppler E’ (E/E’), E/flow propagation velocity (E/Vp), isovolumetric relaxation time/time to E’-time to E (IVRT/TE’-TE), ventilatory efficiency (VE/VCO2slope), O2 consumption at anaerobic threshold and at peak exercise (VO2AT, VO2peak) as well as NT-pro brain natriuretic peptide (NTpro-BNP) were assessed in relation to left ventricular filling pressure and outcome. Results: NT-proBNP, VO2AT, VE/VCO2slope as well as echocardiographic surrogates E/E’ and E/flow propagation velocity were indicators of elevated end diastolic filling pressure. In multivariable analysis, VO2AT was the only independent predictor. NT-proBNP was the only surrogate of left ventricular filling pressure which predicted outcome. Conclusion: In patients with asymptomatic valvular heart disease and preserved systolic function, spiroergometric parameters and NT-proBNP performed best to assess filling pressure. Only NT-proBNP showed prognostic value in this cohort.
Linking Geology and Microbiology: Inactive Pockmarks Affect Sediment Microbial Community Structure
Thomas H. A. Haverkamp, ?yvind Hammer, Kjetill S. Jakobsen
PLOS ONE , 2014, DOI: 10.1371/journal.pone.0085990
Abstract: Pockmarks are geological features that are found on the bottom of lakes and oceans all over the globe. Some are active, seeping oil or methane, while others are inactive. Active pockmarks are well studied since they harbor specialized microbial communities that proliferate on the seeping compounds. Such communities are not found in inactive pockmarks. Interestingly, inactive pockmarks are known to have different macrofaunal communities compared to the surrounding sediments. It is undetermined what the microbial composition of inactive pockmarks is and if it shows a similar pattern as the macrofauna. The Norwegian Oslofjord contains many inactive pockmarks and they are well suited to study the influence of these geological features on the microbial community in the sediment. Here we present a detailed analysis of the microbial communities found in three inactive pockmarks and two control samples at two core depth intervals. The communities were analyzed using high-throughput amplicon sequencing of the 16S rRNA V3 region. Microbial communities of surface pockmark sediments were indistinguishable from communities found in the surrounding seabed. In contrast, pockmark communities at 40 cm sediment depth had a significantly different community structure from normal sediments at the same depth. Statistical analysis of chemical variables indicated significant differences in the concentrations of total carbon and non-particulate organic carbon between 40 cm pockmarks and reference sample sediments. We discuss these results in comparison with the taxonomic classification of the OTUs identified in our samples. Our results indicate that microbial communities at the sediment surface are affected by the water column, while the deeper (40 cm) sediment communities are affected by local conditions within the sediment.
Synaptic Elements for GABAergic Feed-Forward Signaling between HII Horizontal Cells and Blue Cone Bipolar Cells Are Enriched beneath Primate S-Cones
Christian Puller, Silke Haverkamp, Maureen Neitz, Jay Neitz
PLOS ONE , 2014, DOI: 10.1371/journal.pone.0088963
Abstract: The functional roles and synaptic features of horizontal cells in the mammalian retina are still controversial. Evidence exists for feedback signaling from horizontal cells to cones and feed-forward signaling from horizontal cells to bipolar cells, but the details of the latter remain elusive. Here, immunohistochemistry and confocal microscopy were used to analyze the expression patterns of the SNARE protein syntaxin-4, the GABA receptor subunits α1 and ρ, and the cation-chloride cotransporters NKCC and KCC2 in the outer plexiform layer of primate retina. In macaque retina, as observed previously in other species, syntaxin-4 was expressed on dendrites and axon terminals of horizontal cells at cone pedicles and rod spherules. At cones, syntaxin-4 appeared densely clustered in two bands, at horizontal cell dendritic tips and at the level of desmosome-like junctions. Interestingly, in the lower band where horizontal cells may synapse directly onto bipolar cells, syntaxin-4 was highly enriched beneath short-wavelength sensitive (S) cones and colocalized with calbindin, a marker for HII horizontal cells. The enrichment at S-cones was not observed in either mouse or ground squirrel. Furthermore, high amounts of both GABA receptor and cation-chloride cotransporter subunits were found beneath primate S-cones. Finally, while syntaxin-4 was expressed by both HI and HII horizontal cell types, the intense clustering and colocalization with calbindin at S-cones indicated an enhanced expression in HII cells. Taken together, GABA receptors beneath cone pedicles, chloride transporters, and syntaxin-4 are putative constituents of a synaptic set of proteins which would be required for a GABA-mediated feed-forward pathway via horizontal cells carrying signals directly from cones to bipolar cells.
High speed shadowgrpah of a L/D cavity at Mach 0.7 and 1.5
Ryan Schmit,Frank Semmelmayer,Mitch Haverkamp,James Grove
Physics , 2011,
Abstract: This is article highlights the fluid dynamics video of a rectangular cavity with an L/D of 5.67 at Mach 0.7 and 1.5
An Exceptional Generalization of the Poisson Distribution  [PDF]
Per-Erik Hagmark
Open Journal of Statistics (OJS) , 2012, DOI: 10.4236/ojs.2012.23039
Abstract: A new two-parameter count distribution is derived starting with probabilistic arguments around the gamma function and the digamma function. This model is a generalization of the Poisson model with a noteworthy assortment of qualities. For example, the mean is the main model parameter; any possible non-trivial variance or zero probability can be attained by changing the other model parameter; and all distributions are visually natural-shaped. Thus, exact modeling to any degree of over/under-dispersion or zero-inflation/deflation is possible.
Global Environmental Coordination: How to Overcome the Double Collective Action Problematic?  [PDF]
Jan-Erik Lane
Sociology Mind (SM) , 2013, DOI: 10.4236/sm.2013.31013

The need for stronger global coordination of environmental policies has become ever more obvious, but there are no formal arrangements in sight. The UN framework of UNEP is not delivering effective policies. Only global environmental coordination on the successful model of the World Band and the IMF can stem the rising emissions numbers and projections—quantitative voting reflecting the differences in size between the states of the world. However, the system of weighted voting typical of the WB and the IMF must be reformed in an egalitarian manner, when a global ecology organisation is set up, reducing their excessive voting power disparities. This paper suggests a simple but effective mechanism for reducing these voting power disparities, decreasing all member country votes by either the square root or the cube root expression.

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