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1.
S.S. Makridis E.I. Gkanas G. Panagakos E.S. Kikkinides A.K. Stubos P. Wagener S. Barcikowski 《International Journal of Hydrogen Energy》2013
Hydrogen is a promising alternative energy carrier that can potentially facilitate the transition from fossil fuels to sources of clean energy because of its prominent advantages such as high energy density (142 MJ kg−1), great variety of potential sources (for example water, biomass, organic matter), and low environmental impact (water is the sole combustion product). However, due to its light weight, the efficient storage of hydrogen is still an issue investigated intensely. Various solid media have been considered in that respect among which magnesium hydride stands out as a candidate offering distinct advantages. 相似文献
2.
Zarski John J.; Sweeney Thomas J.; Barcikowski Robert S. 《Canadian Metallurgical Quarterly》1977,24(1):1
Examined the relationship between counselor social interest and 3 dimensions of counseling effectiveness. 99 students and 8 counselors at a university counseling center participated, and data were analyzed using a multivariate trend analysis. Measures included the Early Recollection Questionnaire, the Rating Scale of Social Interest Characteristics, and the Counseling Evaluation Inventory. Results show that the counselor's social interest score was significantly related to the client's scores on satisfaction, self-acceptance, and sociability. Experimental support was obtained for one of the major contributions of Adlerian theory, the concept of social interest. Implications of the findings for successful counseling outcomes are discussed. (30 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
3.
Characterisation and modification of the heat affected zone during laser material processing of wood and wood composites 总被引:1,自引:0,他引:1
The heat affected zones (HAZ) at laser cut and laser joint wooden material surfaces were characterised measuring the temperature profile of the process within the cut kerf of particleboard and plywood, as well as the HAZ of the CO2 laser cut and Nd:YAG laser joint pine (Pinus sylvestris L.) surface using microscopy, UV microspectrophotometry and pyrolysis-GC/MS. The width of the HAZ can be selectively modified within the range of 14–70 μm. The HAZ systematically depends on the material and process parameters, such as earlywood or latewood fibre, cut direction and laser energy per section. The thermal induced changes in wood composition were analysed for lignins and carbohydrates. The chemical and structural modifications seem to be most intense at the laser treated surface and decreases to levelling off at 35–40 μm distance from the surface. 相似文献
4.
Ronny Pfeifer Dirk HerzogMichael Hustedt Stephan Barcikowski 《Journal of Materials Processing Technology》2010,210(14):1918-1925
Shape memory alloys (SMAs), in particular Nitinol (NiTi), are of increasing interest in research and industry due to their outstanding properties, e.g. the shape memory effect (SME) and high biocompatibility. Obviously, it is necessary to machine these elements from NiTi sheet materials using suitable processing methods that provide high precision and retain the shape memory effect. Pulsed Nd:YAG laser cutting of 1 mm thick NiTi shape memory alloys for medical applications (SMA-implants) has been investigated. Due to the local energy input only small heat-affected zones (HAZ) occur and the shape memory properties remain. The influence of key parameters like pulse energy, pulse width, and spot overlap on the cut geometry, roughness and HAZ is shown. 相似文献
5.
Bohl A Rohm HW Ceschi P Paasche G Hahn A Barcikowski S Lenarz T Stöver T Pau HW Schmitz KP Sternberg K 《Journal of materials science. Materials in medicine》2012,23(9):2151-2162
A cochlear implant (CI)-associated local drug delivery system based on dexamethasone (DMS) was developed with the purpose to inhibit the growth of fibrotic tissue which influences the signal transmission from the CI to the neurons of the inner ear. For the realization of a targeted DMS delivery the following concepts were combined: modification of the silicone-based electrode carrier by incorporation of DMS and a DMS-containing polymeric coating chemically attached on the surface of the electrode carrier. It was demonstrated that the coated CI showed a high coating stability in a simulated implantation procedure. The in vitro drug release studies in a quasi-stationary model revealed a faster DMS release in the initial phase originating from the DMS-containing coatings and then a lower and sustained DMS release originating from the DMS-loaded silicone carrier. The performed in vitro biocompatibility study confirmed that the released DMS was non-toxic for cultured spiral ganglion cells. 相似文献
6.
Waag Friedrich Fares Wessam I. M. A. Li Yao Andronescu Corina Gökce Bilal Barcikowski Stephan 《Journal of Materials Science》2022,57(4):3041-3056
Journal of Materials Science - Alloy nanoparticles offer the possibility to tune functional properties of nanoscale structures. Prominent examples of tuned properties are the local surface... 相似文献
7.
Intartaglia R Barchanski A Bagga K Genovese A Das G Wagener P Di Fabrizio E Diaspro A Brandi F Barcikowski S 《Nanoscale》2012,4(4):1271-1274
Biofunctionalized silicon quantum dots were prepared through a one step strategy avoiding the use of chemical precursors. UV-Vis spectroscopy, Raman spectroscopy and HAADF-STEM prove oligonucleotide conjugation to the surface of silicon nanoparticle with an average size of 4 nm. The nanoparticle size results from the size-quenching effect during in situ conjugation. Photoemissive properties, conjugation efficiency and stability of these pure colloids were studied and demonstrate the bio-application potential, e.g. for nucleic acid vector delivery with semiconducting, biocompatible nanoparticles. 相似文献
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9.
Anne Hahn Timo Stöver Gerrit Paasche Marian Löbler Katrin Sternberg Henning Rohm Stephan Barcikowski 《Advanced Engineering Materials》2010,12(5):B156-B162
Polymeric nanomaterials are gaining increased interest in medical applications due to the sustained release of bioactive agents. Within this study nanomaterials are fabricated using laser ablation of silver and copper in polymer‐doped organic liquids thus allowing to produce customized drug release systems. A strategy is shown to determine the therapeutic window for cells relevant for cochlear implant electrodes, defined by the viability of L929 fibroblasts, PC12 neuronal cells, and spiral ganglion cells on different concentrations of silver and copper ions. The distribution of nanoparticles within the silicone polymer matrix is determined using transmission electron microscopy. Hexane doped with 1% silicone resin is found to be an appropriate liquid matrix to fabricate a nanocomposite with a constant ion release rate. Silver ions of 10 µmol L?1 or copper ions of 100 µmol L?1 cause a suppression of tissue growth without inhibiting neuronal cell growth. The copper nanoparticle content of 0.1 wt% of the silicone composite releases ion concentrations which fit the therapeutic window. 相似文献
10.
Sebastian Grade Jörg Eberhard Philipp Wagener Andreas Winkel Csaba Laszlo Sajti Stephan Barcikowski Meike Stiesch 《Advanced Engineering Materials》2012,14(5):B231-B239
The inhibition of bacterial growth through effective non‐toxic antimicrobial substances is of great importance for the prevention and therapy of implant infections in various medical disciplines. For the evaluation of a therapeutic window of silver nanoparticles (AgNPs), their bactericidal properties were tested in agar composites and colloids on four medical relevant bacteria. Therefore, we produced AgNPs using high‐power nanosecond laser ablation in water showing a log‐normal particle diameter distribution centered at 17 nm. Bacteria were incubated with AgNP concentrations ranging from 5 to 70 µg · mL?1 and the growth rate was recorded. Additionally, cytotoxic effects of AgNPs on human gingival fibroblasts were examined. The experiments demonstrated that laser‐synthesized AgNPs resulted in a significant bacterial growth inhibition of more than 80% at the indicated concentrations in a solid agar model (Pseudomonas aeruginosa 10 µg · mL?1, Streptococcus salivarius 10 µg · mL?1, Escherichia coli 20 µg · mL?1, Staphylococcus aureus 70 µg · mL?1). In a planktonic bacteria model, the growth of the tested bacteria was significantly delayed by the addition of AgNPs at a concentration of 35 µg · mL?1. The cytotoxic assays showed limited adverse effects on human fibroblasts at concentrations of less than 20 µg · mL?1. The present study illustrates the strong antibacterial effects of ligand‐free, laser‐generated AgNPs that exhibit moderate cytotoxic effects, resulting in a therapeutically applicable concentration of AgNPs for medical purposes between 10 and 20 µg · mL?1. 相似文献