Effect of chondroitin sulfate on osteogenetic differentiation of human mesenchymal stem cells

Chondroitin sulfate (CS) has anti-inflammatory properties and increases the regeneration ability of injured bone. In different in vivo investigations on bone defects the addition of CS to calcium phosphate bone cement has lead to an enhanced bone remodeling and increased new bone formation. The goal of this study was to evaluate the cellular effects of CS on human mesenchymal stem cells (hMSCs). In cell culture experiments hMSCs were incubated on calcium phosphate bone cements with and without CS and cultivated in a proliferation and an osteogenetic differentiation media. Alkaline phosphatase and the proliferation rate were determined on days 1, 7 and 14. Concerning the proliferation rates, no significant differences were detected. On days 1, 7 and 14 a significantly higher activity of alkaline phosphatase, an early marker of osteogenesis, was detected around CS modified cements in both types of media. The addition of CS leads to a significant increase of osteogenetic differentiation of hMSCs. To evaluate the influence of the osteoconductive potency of CS in twelve adult male Wistar rats, the interface reaction of cancellous bone to a nanocrystalline hydroxyapatite cement containing type I collagen (CDHA/Coll) without and with CS (CDHA/Coll/CS) was evaluated. Cylindrical implants were inserted press-fit into a defect of the tibial head. 28 days after the operation the direct bone contact and the percentage of newly formed bone were significantly higher on CDHA/Coll/CS-implants (p < 0.05). The addition of CS appears to enhance new bone formation on CDHA/Coll-composites in the early stages of bone healing. Possible mechanisms are discussed.     

Rapid and scalable method for direct and indirect microstructuring of vertical aligned carbon nanotubes

Multi-walled carbon nanotube (MWCNT) films are grown by chemical vapor deposition (CVD) on silicon substrates using an alumina buffer and a Fe/Co layer as catalyst with different Fe/Co ratios. For both coatings, a scalable wet-chemical technique is applied. The highest CNT forests (100–125 μm) are obtained with Fe content between 60 and 80 wt.%. After deposition of the films, direct laser interference patterning (DLIP) method is used for fabricating micro patterns of the CNTs, using a frequency tripled Nd:YAG laser emitting 10 ns pulses. Two different approaches for fabricating periodic MWCNT arrays are presented. The first approach is the direct patterning of the CNT layer itself (CNT-DLIP) obtaining well defined line-like structures with 10 μm spatial period. By adjusting the laser fluence (from 150 to 250 mJ cm^− 2) and the number of laser pulses (from 1 to 20), the morphology (structure depth and line width) of the fabricated arrays can be varied. Thermal simulations of the CNT ablation process validate the experimental observations. The second approach involves indirect patterning of the CNTs, by fabricating line-like structures on the iron/cobalt catalyst layer (CAT-DLIP). In the last case, moderate energy densities (100 mJ cm^− 2) permitted to remove the catalyst layer locally at the interference maxima positions. By altering the number of laser pulses from 1 to 20 the line width can be tuned. The CNT forests are subsequently grown on the patterned catalyst.     

Six sigma as a business process management method in services: analysis of the key application problems

Apart from being applied in production, Six Sigma has grown considerably in importance as a business process management (BPM) method in services. The transfer of the method from production to service applications does, however, pose problems which affect the success of implementing Six Sigma as a BPM method in services. For a successful application of the Six Sigma method in services it is helpful to know these possible problems in order to be able to avoid them and to achieve the goals of Six Sigma improvement projects. In addition from a theoretical view knowing the problems is a first step for further development of the Six Sigma method. Therefore, the present article deals with the following questions: which key problems regarding the application of Six Sigma in services are mentioned in the literature and which phases of the Six Sigma cycle can they be assigned to? The existing literature on this subject is reviewed and a qualitative content analysis of its contents is presented. Additionally, a survey based on the problems found in the literature is conducted to compare theory and practice. The evaluation of the results shows, on the one hand, that to date the problems of the application of Six Sigma in services have little been dealt with. On the other hand the evaluation provides a survey of the problems structured in accordance to the phases of the Six Sigma cycle. Thus, the present paper offers new findings as regards the state-of-the-art of the Six Sigma method.     

Is longing only for Germans? A cross-cultural comparison of Sehnsucht in Germany and the United States.

Sehnsucht, the longing or yearning for ideal yet seemingly unreachable states of life, is a salient topic in German culture and has proven useful for understanding self-regulation across adulthood in a German sample (e.g., Scheibe, Freund, & Baltes, 2007). The current study tested whether findings for German samples could be generalized to the more individualistic and agentic U.S. American culture. Four samples of U.S. American and German participants (total N = 1,276) age 18 to 81 years reported and rated their 2 most important life longings and completed measures of subjective well-being and health. Measurement equivalence was established at the level of factor loadings for central life longing characteristics. German and U.S. American participants did not differ in self-reported ease of identifying personal life longings or their intensity. In comparison to Germans, however, U.S. Americans associated life longings less with utopian, unattainable states and reported less salience of the concept in everyday life. Associations with measures of adaptation suggest that life longings can be both functional and dysfunctional for development in both cultures. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Strontium isotopic signatures of natural mineral waters,the reference to a simple geological map and its potential for authentication of food

This paper presents the investigation of strontium isotope ratios of about 650 different European natural mineral waters as part of the food traceability project “TRACE” funded by the EU. Analysed ⁸⁷Sr/⁸⁶Sr values in the natural mineral waters range from 0.7035 to 0.7777, which indicates an influence by a great diversity of rocks from young mantle derived basaltic rocks to very old silicic continental crust.