Degussa AG Research Articles

Development of a prototype of a theranostic system based on silica nanoparticles with immobilized fluorescent dyes and VEGF targeting ligand.

Background. Administration of certain drugs causes undesirable effects associated with the systemic effect of the active substance on the entire body. Selective targeting of the drug to the affected tissue promotes a selective increase in the concentration of the substance in the area of interest, thereby reducing the systemic effect and enhancing the local therapeutic effect.Objective. Development of a targeted delivery system for theranostic agents using recombinant human vascular endothelial growth factor type A (rhVEGF-A121) as a targeting ligand.Design and method. To create the theranostic complex, commercially available reagents were used: the recombinant protein rhVEGF-A121 (cat.#: PSG140-10, LLC CyStorLab, Skolkovo, Russia) and fumed silica Aerosil (A-200, Degussa AG, Germany). The tosyl spacer that interconnects both components was synthesized in the laboratory. Protein conjugation with fluorophores was also carried out in-house. Indocyanine green (ICG; Sigma-Aldrich, USA) and rhodamine B (JSC Lenreaktiv, St. Petersburg, Russia) were taken for immobilization.Results. In the course of the work, functionalization of silica nanoparticles (SiNPs) with a tosyl spacer was carried out, conjugates of SiNPs with rhVEGF-A121 were synthesized, and theranostic constructs based on SiNPs were obtained, including rhVEGF-A121 as a targeting ligand, and ICG/Rhodamine B as a visualizing label.Conclusion. In the presented study, a prototype of a complex for targeted delivery of a theranostic agent to tissues with an active angiogenesis process, for example, to tumor and ischemic tissues, was developed. To solve the problem, we immobilized on the surface of SiNP a recombinant protein of human vascular endothelial growth factor (rhVEGF) to use as a guide ligand. Such a synthetic construct will help to deliver diagnostic and/ or medicinal substances packed in SiNP directly to cells that overexpress extracellular specific receptors of the VEGFR family. In subsequent in vivo experiments, delivery efficiency will be assessed by tissue accumulation of the fluorophores ICG and rhodamine B, which have been conjugated to the targeting ligand protein. The physicochemical characteristics of the obtained samples were studied by the methods of spectrophotometry and dynamic light scattering.

Surface treatment of titanium dioxide nanopowder using rotary electrode dielectric barrier discharge reactor

Titanium dioxide (TiO2) nanopowder (P-25; Degussa AG) was treated using dielectric barrier discharge (DBD) in a rotary electrode DBD (RE-DBD) reactor. Its electrical and optical characteristics were investigated during RE-DBD generation. The treated TiO2 nanopowder properties and structures were analyzed using x-ray diffraction (XRD) and Fourier-transform infrared spectroscopy (FTIR). After RE-DBD treatment, XRD measurements indicated that the anatase peak theta positions shifted from 25.3° to 25.1°, which can be attributed to the substitution of new functional groups in the TiO2 lattice. The FTIR results show that hydroxyl groups (OH) at 3400 cm−1 increased considerably. The mechanism used to modify the TiO2 nanopowder surface by air DBD treatment was confirmed from optical emission spectrum measurements. Reactive species, such as OH radical, ozone and atomic oxygen can play key roles in hydroxyl formation on the TiO2 nanopowder surface.

Sol-gel TiO2 films as NO2 gas sensors

TiO2 films were prepared by a sol-gel technique with commercial TiO2 powder as a source material (P25 Degussa AG). After a special treatment, printing paste was prepared. The TiO2 layers were formed by means of drop-coating on Si-control wafers and on the Au-electrodes of quartz resonators. The surface morphology of the films was examined by scanning electron microscopy (SEM). Their structure was studied by Raman spectroscopy and the surface composition was determined by X-ray photoelectron spectroscopy (XPS). The layers had a grain-like surface morphology and consisted mainly of anatase TiO2 phase. The sensitivity of the TiO2 films to NO2 was assessed by the quartz crystal microbalance (QCM) technique. To this end, the films were deposited on both sides of a 16-MHz QCM. The sensing characteristic of the TiO2-QCM structure was investigated by measuring the resonant frequency shift (ΔF) of the QCM due to the mass loading caused by NO2 adsorption. The Sauerbrey equation was applied to establish the correlation between the QCM frequency changes measured after exposure to different NO2 concentrations and the mass-loading of the QCM. The experiments were carried out in a dynamic mode on a special laboratory setup with complete control of the process parameters. The TiO2 films were tested in the NO2 concentration interval from 10 ppm to 5000 ppm. It was found that a TiO2 loading of the QCM by 5.76 kHz corresponded to a system sensitive to NO2 concentrations above 250 ppm. On the basis of the frequency-time characteristics (FTCs) measured, AF at different NO2 concentrations was defined, the adsorption/desorption cycles were studied and the response and recovery times were estimated. The results obtained show that the process is reversible in the NO2 interval investigated. The results further suggested that TiO2 films prepared by a sol-gel method on a QCM can be used as a sensor element for NO2 detection.

Preparation, Characterization and Photocatalytic Application of Carbonate Modified Titania

Carbonate is a common pollutant in water and wastewater. A study to understand its influence on the photodegradation rates is necessary especially when TiO2/UV technique is emerging as an advanced technology for pollution abatement. In the present investigation, we report surface modification of titanium dioxide using carbonate ions, characterization of carbonate modified titanium dioxide (CMT) and photocatalytic application of carbonate modified TiO2. Titanium dioxide from two different sources namely BDH, Mumbai and Degussa AG, Germany was used as photocatalyst. The CMT catalysts were characterized using potentiometry, FT-IR and XPS. Approximately, 18.9 mg CO3/g CMT(BDH) and 8.13 mg CO3/g CMT(Degussa) was found loaded as determined by potentiometry. The C 1s and O 1s binding energies observed at 289.2 and 531.3 eV, respectively were attributed to surface carbonate species. The adsorption and photodegradation of Acid Blue I dye examined using neat TiO2as well as CMT catalysts revealed that carbonate inhibits catalytic activity for color and Chemical Oxygen Demand (COD) removal. The photo degradation rate constant (k, s-1) decreases gradually with increasing concentration of carbonate. Thus, in the absence of carbonatekdyeis 5.45 × 10-4s-1(R2= 0.97) andkCODis 3.50 × 10-5s-1(R2= 0.97). At 100 mg/L CO32-,kdyeis 0.16 × 10-4s-1(R2= 0.96) andkCODis 2.66 × 10-5s-1(R2= 0.98). In addition, the carbonate spiking studies revealed the onset of inhibition soon after the addition of carbonate into reacting suspensions of TiO2. The results suggest that carbonate inhibits catalytic activity through formation of strong surface complex under suitable pH by displacing OH2+and OH groups from TiO2surface. This results not only in fewer (OH)surfacegroups available for h+trapping for oxidation into OH radicals but also in non-availability of adsorption sites for the dye molecules. A pretreatment to remove carbonate from (waste) water appears necessary prior to application of TiO2/UV technique

Bio‐based production of organic acids with Corynebacterium glutamicum

The shortage of oil resources, the steadily rising oil prices and the impact of its use on the environment evokes an increasing political, industrial and technical interest for development of safe and efficient processes for the production of chemicals from renewable biomass. Thus, microbial fermentation of renewable feedstocks found its way in white biotechnology, complementing more and more traditional crude oil-based chemical processes. Rational strain design of appropriate microorganisms has become possible due to steadily increasing knowledge on metabolism and pathway regulation of industrially relevant organisms and, aside from process engineering and optimization, has an outstanding impact on improving the performance of such hosts. Corynebacterium glutamicum is well known as workhorse for the industrial production of numerous amino acids. However, recent studies also explored the usefulness of this organism for the production of several organic acids and great efforts have been made for improvement of the performance. This review summarizes the current knowledge and recent achievements on metabolic engineering approaches to tailor C. glutamicum for the bio-based production of organic acids. We focus here on the fermentative production of pyruvate, l-and d-lactate, 2-ketoisovalerate, 2-ketoglutarate, and succinate. These organic acids represent a class of compounds with manifold application ranges, e.g. in pharmaceutical and cosmetics industry, as food additives, and economically very interesting, as precursors for a variety of bulk chemicals and commercially important polymers.Funding Information Work in the laboratories of the authors was supported by the Fachagentur Nachwachsende Rohstoffe (FNR) of the Bundesministerium für Ernährung, Landwirtschaft und Verbraucherschutz (BMELV; FNR Grants 220-095-08A and 220-095-08D; Bio-ProChemBB project, ERA-IB programme), by the Deutsche Bundesstiftung Umwelt (DBU Grant AZ13040/05) and the Evonik Degussa AG.

Protein, population, politics. How protein can be supplied sustainably in the 21st century. Edited by Hubert Wennemer, Gerhard Flachowsky and Volker Hoffmann. Degussa AG, German Federal Agriculture Research Center (FAL), Council for Tropical and Subtropical Agriculture (ATSAF). Published in 2006, 160 pp

Protein, population, politics. How protein can be supplied sustainably in the 21st century. Edited by Hubert Wennemer, Gerhard Flachowsky and Volker Hoffmann. Degussa AG, German Federal Agriculture Research Center (FAL), Council for Tropical and Subtropical Agriculture (ATSAF). Published in 2006, 160 pp

The investigation of sensing mechanism of ethanol vapour in polymer-nanostructured carbon composite

Abstract Polymer-nanostructured carbon composites (PNCC) using three different polymers as composite matrix materials (polyvinylacetate (PVAc), polyethylene glycol (PEG) and ethylene-vinylacetate copolymer (EVA)) have been developed. High structure carbon black Printex XE2 (Degussa AG) was used as a composites filler. Ethanol vapour sensor-effect of composites was determined as a change of electrical resistance as the composite was held in ethanol vapour for 30 seconds. Reversibility of electrical resistance of PNCC, response stability and repeatability have been measured and compared. The electrical resistance response of EVA-nanostructured carbon composite (EVA-NCC) to ethanol vapour as a function of vinylacetate content in the copolymer has been evaluated. Promising ethanol vapour sensor-effect has been observed for PEG-NCC followed by PVAc-NCC and EVA-NCC.

This Special Issue of Microsystem Technologies is devoted to Professor Dr.-Ing. Jürgen Haußelt on the occasion of his 65th birthday

Professor Dr.-Ing. Jurgen Hauselt, for many years the Head of the Institute of Materials Research III at the Forschungszentrum Karlsruhe, today Karlsruhe Institute of Technology (KIT), and also Professor and Head of the Laboratory of Materials Process Technology at the University of Freiburg will be celebrating his 65th birthday on May 21, 2011. His outstanding professional career features about 16 years of work in industry and 24 years in science and teaching at academic and research institutions. Jurgen Hauselt studied physics at the University of Erlangen-Nurnberg in Bavaria, Germany, and finished his diploma thesis in 1971. Under the guidance of the Professors Bernhard Ilschner and Wolfgang Blum at the Institute of Materials Science of the university he accomplished a PhD thesis on the recovery of the dislocation structure after stationary deformation with an Al-Zn alloy. After being awarded his doctoral degree (Dr.-Ing.) in 1975, he worked as a scientific assistant at this institute and during this time he took a year-long sabbatical for a postdoc position with Prof. W.D. Nix at Stanford University, USA. Back from the USA, Jurgen Hauselt started his industrial career in July 1977 as group leader in the Metal Research Department of Degussa AG at Hanau-Wolfgang, Germany. At the beginning he worked on the development of new alloys for dental and brazing technologies. In 1983 he became the Technical Director of Degussa Dental, Inc. at Long Island City, USA. As consequence of his remarkable success, he was promoted in November 1984 to the position of the division manager ‘Metallurgy’ at Degussa-Metal Research at Hanau-Wolfgang. The next steps of his career at Degussa had been appointments to a department head in 1987 connected with an enlargement of responsibilities for electronic materials, thin film materials and structural ceramics and in 1989 to the department director ‘‘Manufacturing Technology’’ with responsibility for the Central Research ‘‘Metal’’ which included melting and casting techniques as well as metal forming and powder metallurgy. A new phase of Jurgen Hauselt’s life began on October 1, 1993 with the acceptance of the position of Head of the Institute of Materials Research III at the Kernforschungszentrum Karlsruhe which was renamed Forschungszentrum Karlsruhe in 1995. In 1996 he was additionally appointed Professor and Head of the Laboratory of Materials Process Technology at the Department of Microsystems Engineering (IMTEK) at the University of Freiburg. Promoted by the two appointments of Jurgen Hauselt, a close scientific and personal cooperation of both institutions has developed in the field of Microsystems Technology, particularly. Credit is due to him also for his considerable contribution as vice-spokesman to the formation of the DFG-Collaborative Research Centre 499 ‘‘Design, production and quality assurance of moulded microcomponents made of metallic and ceramic materials’’. By reason of his outstanding scientific competence in several fields of materials science and process technologies for microsystems but also due to his charismatic and engaging personality, his membership in numerous executive and scientific committees has been very much appreciated. Beside his manifold activities in the science community and as a university professor, Jurgen Hauselt K.-H. Zum Gahr (&) Karlsruhe Institute of Technology, Karlsruhe, Germany e-mail: karl-heinz.zumgahr@kit.edu

Feeding ruminally protected methionine to pre- and postpartum dairy cows: effect on milk performance, milk composition and blood parameters

An experiment was conducted to evaluate the effect of ruminally protected methionine (Mepron®, Degussa AG, Germany) in dairy cows. Three weeks before calving 36 cows (Holstein and Czech Fleckvieh breeds) were assigned to one of the two dietary treatments (M and O), and received a total mixed ration with protected methionine at 18.2 g per head per day or without this supplement. After calving, both groups were divided into two subgroups and fed a diet for dairy cows based on ensiled feeds and concentrates for 90 days. A half of the cows received protected methionine (subgroups MM and OM), the other cows were fed the same diet without protected methionine (subgroups MO and OO). Milk yield in cows fed protected methionine for the whole experiment duration (cows MM) was higher and feed intake was lower than in cows of the other groups. The effect of protected methionine on milk yield was not, however, statistically significant (<I>P</I> > 0.05). Effects of protected methionine on milk fat and protein were small and inconsistent. Supplemental methionine significantly increased the methionine concentration in serum (<I>P</I> < 0.05) while the methionine concentration in milk was not increased quite significantly (<I>P</I> < 0.10). Concentrations of essential amino acids in milk were significantly or marginally significantly higher in cows fed protected methionine. In summary, the supplementation of ruminally protected methionine at 18.2 g per head per day had beneficial, but small and mostly statistically insignificant effects on milk performance and milk composition.

Degussa AG and its Holocaust Legacy

This case is designed to help students analyze decision making from various ethical perspectives and to use stakeholder analysis. The case perspective is that of the CEO of Degussa AG, a multispecialty chemical company, headquartered in Dusseldorf, Germany. Degussa is considering whether to submit a bid to supply its anti-graffiti coating, Protectosil®, for a new Memorial to the Murdered Jews in Europe being planned for Berlin. Degussa’s ethical dilemma is that a former Degussa subsidiary, Degesch, manufactured and supplied the Zyklon B nerve gas used by the Nazis to kill Jews in the concentration camps during World War II. Although Degussa has made attempts both to acknowledge and to atone for its war-time Nazi collaboration, public disclosure of its bid has the potential to engulf Degussa in controversy when activists and Jewish leaders learn of it. Students are asked to evaluate the bid’s benefits and costs to Degussa’s stakeholders, to consider the relevance of a company’s historical legacy to contemporary decision making, and to explore how German corporate history during and after the Holocaust has parallels to human rights issues in other countries.

Organising new business development: open innovation at Degussa

PurposeThe purpose of this paper is to analyse different organisational tools of business development used in practice. This analysis seeks to address the question of how an organisation can achieve the recurring shift from exploration to exploitation and at the same time manage to balance its open and closed innovation tools.Design/methodology/approachThe empirical basis for analysing the organisational implications of open vs closed innovation is built by Creavis, the business venturing arm of Degussa AG, a specialty chemicals company headquartered in Germany.FindingsCompanies face the ambiguity of creating new business options and exploiting these at a later stage. Since exploitative and explorative units require a different organisational set‐up, it is difficult for a company to shift its exploratory endeavours to exploitative means. The presented case study offers an answer to this dilemma by showing how organisations manage to combine both by a unique organisational set‐up allowing for an evolutionary approach of shifting exploratory work into exploitative results.Practical implicationsThe insights derived from the case study clearly present a way of dealing with ambidexterity in new business development. The in‐depth analysis advances the understanding of how organisations may successfully conduct business development and, in particular, which organisational tools they may use.Originality/valueThis paper is based on an original case study by the authors. It integrates management theory with a real life example to foster management research in new business development and the particular question of how to deal with the need of organisations to combine both exploratory and exploitative units and support their interaction as well as employing different approaches to innovation, i.e. open vs closed innovation.

The Effect of Transition Metal Doping on the Photooxidation Process of Titania-Clay Composites

Montmorillonite- composites containing various transition metal ions (silver, copper, or nickel) were prepared, and their photocatalytic efficiencies were tested in the degradation of ethanol vapor at 70% relative humidity. Two light sources, UV-rich ( = 254 nm) and visible ( = 435 nm), were used. The kinetics of degradation was monitored by gas chromatography. It was established that, in the case of each catalyst, ethanol degradation was more efficient in UV-C ( = 254 nm) than in visible light, furthermore, these samples containing silver or copper ions were in each case about twice more efficient than P25 (Degussa AG.) used as a reference. In photooxidation by visible light, /clay samples doped with silver or copper were also more efficient than the reference sample, P25 . We show that doping metal ions can also be delivered to the surface of the support by ion exchange and significantly alters the optical characteristics of the /clay composite.

Wärmeüberträger

Chemie Ingenieur TechnikVolume 78, Issue 10 p. 1471-1473 ACHEMA-Bericht Wärmeüberträger M. Rinner Dr.-Ing., M. Rinner Dr.-Ing. [email protected] Degussa AG, Process Technology, Rodenbacher Chaussee 4, D-63457 Hanau-WolfgangSearch for more papers by this author M. Rinner Dr.-Ing., M. Rinner Dr.-Ing. [email protected] Degussa AG, Process Technology, Rodenbacher Chaussee 4, D-63457 Hanau-WolfgangSearch for more papers by this author First published: 26 September 2006 https://doi.org/10.1002/cite.200690107AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL No abstract is available for this article. Volume78, Issue10October, 2006Pages 1471-1473 RelatedInformation

Doing Homogeneous Catalysis between Basic Research and Application

AbstractRecent achievements in applied homogeneous catalysis are described. Special focus is given on the development of novel palladium catalysts which are of industrial interest for the synthesis of bulk and fine chemicals. Most of the reported work has been done in an intensive collaboration between the Degussa AG (DHC) and the Leibniz‐Institut für Katalyse e.V. The clear vision of the goal and a close interaction of basic research and applied catalysis have led to a fast development from the initial discovery to the upscaling of the ligands. Such a combination of know how from academic and industrial partners will provide the basis for further innovations in catalysis in future.

An In-Vitro Study of Microleakage Around Class V Cavities Bonded with a Self-Etching Material Versus a Conventional Two-Bottle System

To evaluate the microleakage around class V restorations restored with either a self-etching adhesive system or a conventional two-bottle adhesive system used with "total etch" technique, and their recommended resin-based composites (RBC). Two types of adhesive systems were used. A self-etching adhesive, Etch and Prime 3.0 (Degussa AG, Hanau, Germany), and a conventional two-bottle adhesive, Gluma Solid Bond (Heraeus Kulzer, Dormagen, Germany). The bonding systems were used in strict accordance with the manufacturers' instructions, except that, with the two-bottle adhesive system, the cavities were filled with either a "wet" or a "dry" bonding technique, subsequent to acid-etching with 20% phosphoric acid. Etch & Prime 3.0 was used in conjunction with Degufill Mineral (Degussa, Hanau, Germany) RBC and Gluma Solid Bond with Flow Line RBC (Heraeus Kulzer, Dormagen, Germany). Standardised bucco-cervical cavities were prepared on the buccal and lingual surfaces of 15 extracted maxillary first premolar teeth; all cavity margins were in enamel. Ten of the resulting cavities (Group A) were restored using Etch & Prime 3.0 and Degufill Mineral, ten (Group B) using Gluma Solid Bond (Wet Bond), and ten (Group C) using Gluma Solid Bond (Dry Bond). Leakage scores at occlusal and gingival margins were calculated after thermocycling 500 times between baths, held at 5 degrees C and 55 degrees C, respectively, with 30 seconds dwell time in both. Data were analysed by the Fisher Exact Test. There was no statistically significant difference between the self-etching adhesive and conventional two-bottle adhesive systems at either the occlusal or the gingival margins. With the self-etching adhesive, there was no statistically significant difference in leakage scores between occlusal and gingival margins. There was a statistically significant difference between the occlusal and the gingival margins when a "wet" or "dry" bonding technique was used with the conventional two-bottle adhesive system. The results suggest that the application of a conventional two-bottle bonding system used with a "total etch" technique is better than that of a self-etching adhesive system. With the former, the use of a "wet" bonding does not give better results than a "dry" bonding technique.

Thermally modified titania photocatalysts for phenol removal from water

Two kinds of titanium dioxide were used as starting materials for thermal modification: Tytanpol A11 supplied by Chemical Factory “Police” S.A. (Poland) and Degussa P25 supplied by Degussa AG (Germany). The photocatalytic activity of titania materials modified by thermal treatment was tested in the reaction of photocatalytic oxidation of phenol. It was found that the highest activity in the reaction of photocatalytic decomposition of phenol, in case of Tytanpol A11, shows the samples of material modified at temperatures of 700 and 750°C. These catalysts were more active than untreated A11, whereas materials modified at higher temperatures show lower activity. In the case of P25, all thermally treated materials were less active than the unmodified material. The photocatalyst samples were characterized by UV‐Vis/DR, FTIR/DRS, and XRD methods.

The Crucial Role of Trehalose and Structurally Related Oligosaccharides in the Biosynthesis and Transfer of Mycolic Acids in Corynebacterineae

Trehalose (alpha-D-glucopyranosyl-alpha'-D-glucopyranoside) is essential for the growth of the human pathogen Mycobacterium tuberculosis but not for the viability of the phylogenetically related corynebacteria. To determine the role of trehalose in the physiology of these bacteria, the so-called Corynebacterineae, mutant strains of Corynebacterium glutamicum unable to synthesize trehalose due to the knock-out of the genes of the three pathways of trehalose biosynthesis, were biochemically analyzed. We demonstrated that the synthesis of trehalose under standard conditions is a prerequisite for the production of mycolates, major and structurally important constituents of the cell envelope of Corynebacterineae. Consistently, the trehalose-less cells also lack the cell wall fracture plane that typifies mycolate-containing bacteria. Importantly, however, the mutants were able to synthesize mycolates when grown on glucose, maltose, and maltotriose but not on other carbon sources known to be used for the production of internal glucose phosphate such as fructose, acetate, and pyruvate. The mycoloyl residues synthesized by the mutants grown on alpha-D-glucopyranosyl-containing oligosaccharides were transferred both onto the cell wall and free sugar acceptors. A combination of chemical analytical approaches showed that the newly synthesized glycolipids consisted of 1 mol of mycolate located on carbon 6 of the non reducing glucopyranosyl unit. Additionally, experiments with radioactively labeled trehalose showed that the transfer of mycoloyl residues onto sugars occurs outside the plasma membrane. Finally, and in contradiction to published data, we demonstrated that trehalose 6-phosphate has no impact on mycolate synthesis in vivo.

Distraction osteogenesis of the canine mandible: The impact of acute callus manipulation on vascularization and early bone formation

Manipulations of the newly created regenerate, using adjustable multiplanar devices during distraction osteogenesis or as a 1-step molding procedure at the end of the distraction process, may be necessary to correct the position of the mandible. Treatment of complex deformities may require preplanned major angulation provided by adjustable devices. We sought to assess the effects of molding the fresh regenerate on vascularization and early bone formation within clinically relevant dimensions. Evaluation of the nature of the problem in mechanical terms was based on a geometrical model, its dimensions chosen with clinical relevance. Custom-made devices, allowing the simultaneous compression and stretching of a regenerate 10 mm long, were fixed bilaterally in the angular region of beagle mandibles (n = 14). Angulation of 20 degrees (n = 7) or 30 degrees (n = 7) was performed immediately after ending the lengthening period, and the animals were killed after a 7-day consolidation period. The vascular system was stained via intravital Procion red infusion and post mortem carbon ink (Deperussol P130; Degussa AG, Frankfurt, Germany) perfusion to assess possible damages. Qualitative and quantitative evaluations of the mineralized tissue were performed with contact radiography, quantified computed tomography, and histologic assessment. The only finding indicating mechanical forces acting on the regenerate was related to orientation of the collagenous fibers. Vascular damage was not observed. Mineralization patterns were identical in both the compressed and the stretched zone. The degree of angulation had no visible impact on early bone formation, even if compression and stretching of the regenerate at a range of 33% to 54% exceeds most clinical requirements. However, the amount of callus formation differed independent of the shaping angle, revealing parameters other than the degree of angulation to be important. Although the newly forming bone is highly sensitive to nonphysiologic strain during the lengthening process, a completed fresh regenerate, created by distraction osteogenesis, can be manipulated to a considerable extent without endangering early callus formation. Manipulation of the regenerates would provide a precise final result, minimizing the need for secondary corrections and diminishing treatment duration and costs.

Monitoring aerobic Escherichia coli growth in shaken microplates by measurement of culture fluorescence.

Monitoring aerobic Escherichia coli growth in shaken microplates by measurement of culture fluorescence.

Bioavailability of three ruminally protected methionine sources in cattle

The bioavailability of three ruminally protected d, l-methionine products (Smartamine M™; Adisseo, Antony, France; Mepron ® M85, Degussa AG, Hanau, Germany; and METHIO-BY, Inter-Harz GmbH, Elmshorn, Germany) was assessed in six ruminally cannulated steers by means of a standardized blood test. d, l-methionine was supplemented once daily at 07:00 h in amounts of 50 g of methionine per steer for 5 days. The experimental design was a repeated 3×3 Latin square with 14 days periods. Blood samples were obtained by repeated puncture of the jugular veins at 09:00, 13:00 and 17:00 h 3 days before (control) and 5 days after the start of d, l-methionine supplementation. Blood samples within sampling day and steer were pooled for analyses. All three d, l-methionine sources caused elevations of blood plasma methionine but the magnitude of the response differed among sources. Smartamine M™ caused a 2016% increase (464 μmol/l versus 23 μmol/l for the control), whereas Mepron ® M85 and METHIO-BY elevated blood plasma levels by 58 and 82% (39 μmol/l versus 25 μmol/l and 40 μmol/l versus 22 μmol/l, respectively). Smartamine M™ was the most effective source of ruminally protected d, l-methionine.