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5 results on '"Göhler R"'

1. Combination Therapy with Zidovudine Prevents Selection of Human Immunodeficiency Virus Type 1 Variants Expressing High-Level Resistance to L-697,661, a Nonnucleoside Reverse Transcriptase Inhibitor

Author

Staszewski, S., Massari, F. E., Kober, A., Göhler, R., Durr, S., Anderson, K. W., Schneider, C. L., Waterbury, J. A., Bakshi, K. K., Taylor, V. I., Hildebrand, C. S., Kreisl, C., Hoffstedt, B., Schleif, W. A., von Briesen, H., Rübsamen-Waigmann, H., Calandra, G. B., Ryan, J. L., Stille, W., Emini, E. A., and Byrnes, V. W.

Published
1995

2. Darstellung und Einfluss von durchbrochener Bewölkung auf den Ertrag von Photovoltaik-Anlagen und dessen Prognose

Author

Göhler, R., Raabe, Armin, and Zimmer, Janek

Subjects
erneuerbare Energie, Energieversorgung, Photovoltaik, ddc:551, renewable energy, energy consumption, energy supply, photovoltaic system
Abstract

Due to the significant increase of ’renewable energy’ to the total energy the highly fluctuating energy supply, which is due to the constitutional conditions of production among others from photovoltaic systems, becomes a growing problem. As a result, many engineering firms and companies dedicate themselves to the so-called power prediction by which it should be possible to integrate a fast changing energy supply into a necessarily continuous energy supply. The Ingenieurbüro für Last- und Energiemanagement (LEM-Software) used a neural network for this prediction of performance of photovoltaic systems. This networks learn from past knowledge a mathematical patern that can be used for forecasting. Based on this, this article deals with a new parameter for the network which characterizes the probability of broken cloud effects. The global radiation forecast in the surrounding area is analyzed for this index. It turns out that this inhomogeneous index is a better indicator than the standard deviation. A first application shows a slight improvement in the forecast result. However, the time limit for application of the neural network is too short for a final evaluation. Aufgrund des steigenden Anteils ’erneuerbarer Energie’ an der Energieversorgung wird die stark schwankende Energiezufuhr, bedingt durch die naturgegebenen Produktionsbedingungen unter anderem von Photovoltaik-Anlagen, zu einem immer größeren Problem. Infolge dessen widmen sich viele Ingenieurbüros und Firmen sogenannten Leistungsprognosen, mit deren Hilfe es gelingen soll, eine schnell wechselnde Energiebereitstellung in eine notwendigerweise kontinuierliche Energieversorgung zu streichen. Das Ingenieurbüro für Last- und Energiemanagement (LEM-Software) verwendet für diese Vorhersagen der Leistung von Photovoltaik-Anlagen ein künstliches neuronales Netzwerk (KNN). Dieses erlernt aus vergangenen Verhältnissen ein mathematisches Muster, welches für die Prognose angewendet werden kann. Aufbauend darauf befasst sich dieser Artikel mit einem Inhomogenitätsindex f¨ur das Netzwerk, welcher die Wahrscheinlichkeit für das Auftreten schnell wechselnder Bewölkung und von Broken-Cloud-Effekten charakterisiert. Für den Index wird die Globalstrahlungsvorhersage in der näheren Umgebung analysiert. Dabei stellt sich heraus, dass dieser Inhomogenitätsindex ein besserer Indikator als die Standardabweichung ist. Eine erste Anwendung zeigt eine leichte Verbesserung des Prognoseergebnisses, allerdings ist der Zeitraum für die Anwendung des KNN zu kurz für eine abschließende Bewertung.

Published
2016

4. Quantification of osseointegration of plasma-polymer coated titanium alloyed implants by means of microcomputed tomography versus histomorphometry.

Author

Gabler C, Zietz C, Bieck R, Göhler R, Lindner T, Haenle M, Finke B, Meichsner J, Testrich H, Nowottnick M, Frerich B, and Bader R

Subjects
Algorithms, Alloys, Animals, Ethylenediamines, Female, Imaging, Three-Dimensional, Materials Testing, Polyamines, Rats, Rats, Sprague-Dawley, Tibia diagnostic imaging, Tibia pathology, Tibia surgery, X-Ray Microtomography, Coated Materials, Biocompatible, Osseointegration, Prostheses and Implants, Titanium
Abstract

A common method to derive both qualitative and quantitative data to evaluate osseointegration of implants is histomorphometry. The present study describes a new image reconstruction algorithm comparing the results of bone-to-implant contact (BIC) evaluated by means of µCT with histomorphometry data. Custom-made conical titanium alloyed (Ti6Al4V) implants were inserted in the distal tibial bone of female Sprague-Dawley rats. Different surface configurations were examined: Ti6Al4V implants with plasma-polymerized allylamine (PPAAm) coating and plasma-polymerized ethylenediamine (PPEDA) coating as well as implants without surface coating. After six weeks postoperatively, tibiae were explanted and BIC was determined by µCT (3D) and afterwards by histomorphometry (2D). In comparison to uncoated Ti6Al4V implants demonstrating low BIC of 32.4% (histomorphometry) and 51.3% (µCT), PPAAm and PPEDA coated implants showed a nonsignificant increase in BIC (histomorphometry: 45.7% and 53.5% and µCT: 51.8% and 62.0%, resp.). Mean BIC calculated by µCT was higher for all surface configurations compared to BIC detected by histomorphometry. Overall, a high correlation coefficient of 0.70 (p < 0.002) was found between 3D and 2D quantification of BIC. The μCT analysis seems to be suitable as a nondestructive and accurate 3D imaging method for the evaluation of the bone-implant interface.

Published
2015
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5. Evaluation of osseointegration of titanium alloyed implants modified by plasma polymerization.

Author

Gabler C, Zietz C, Göhler R, Fritsche A, Lindner T, Haenle M, Finke B, Meichsner J, Lenz S, Frerich B, Lüthen F, Nebe JB, and Bader R

Subjects
Alloys, Animals, Cell Adhesion, Cell Line, Coated Materials, Biocompatible, Female, Humans, Osteoblasts metabolism, Rats, Osseointegration, Polymerization, Prostheses and Implants, Titanium
Abstract

By means of plasma polymerization, positively charged, nanometre-thin coatings can be applied to implant surfaces. The aim of the present study was to quantify the adhesion of human bone cells in vitro and to evaluate the bone ongrowth in vivo, on titanium surfaces modified by plasma polymer coatings. Different implant surface configurations were examined: titanium alloy (Ti6Al4V) coated with plasma-polymerized allylamine (PPAAm) and plasma-polymerized ethylenediamine (PPEDA) versus uncoated. Shear stress on human osteoblast-like MG-63 cells was investigated in vitro using a spinning disc device. Furthermore, bone-to-implant contact (BIC) was evaluated in vivo. Custom-made conical titanium implants were inserted at the medial tibia of female Sprague-Dawley rats. After a follow-up of six weeks, the BIC was determined by means of histomorphometry. The quantification of cell adhesion showed a significantly higher shear stress for MG-63 cells on PPAAm and PPEDA compared to uncoated Ti6Al4V. Uncoated titanium alloyed implants showed the lowest BIC (40.4%). Implants with PPAAm coating revealed a clear but not significant increase of the BIC (58.5%) and implants with PPEDA a significantly increased BIC (63.7%). In conclusion, plasma polymer coatings demonstrate enhanced cell adhesion and bone ongrowth compared to uncoated titanium surfaces.

Published
2014
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