Joachim Kohn

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ferences between closely related species (Taylor et al. 1994), subspecies (Paetkau & Strobeck 1994) and populations of the same species (Bowcock et al. 1994). Roy et al. (1994) presented a thorough analysis at all three levels for wolves and their close relatives. Gotelli et al. (1994) were able to reveal hybridization between the Ethiopian wolf and(More)
Stem cells that adopt distinct lineages cannot be distinguished based on traditional cell shape. This study reports that higher-order variations in cell shape and cytoskeletal organization that occur within hours of stimulation forecast the lineage commitment fates of human mesenchymal stem cells (hMSCs). The unique approach captures numerous early (24 h),(More)
While the interactions of cells with polymeric substrata are widely studied, the influence of cell-cell cohesiveness on tissue spreading has not been rigorously investigated. Here we demonstrate that the rate of tissue spreading over a two-dimensional substratum reflects a competition or "tug-of-war" between cell-cell and cell-substratum adhesions. We have(More)
The physico-mechanical properties of degradable polymers used for medical applications have been characterized. The following polymers were included in this study: three samples of poly(ortho esters) derived from 3,9-bis(ethylidene 2,4,8,10-tetraoxaspiro[5,5]undecane) and various ratios of 1,6-hexanediol and trans-cyclohexane dimethanol, poly(glycolic(More)
Tyrosine PEG-derived poly(ether carbonate)s were prepared by condensation copolymerization with phosgene. The resulting polymers were random copolymers with weight average molecular weights from 40 000 to 200 000 dalton. Chemical structure and purity were confirmed by NMR and FTIR spectral analysis. General structure property correlations were established.(More)
Previous studies demonstrated that poly(DTE carbonate) and poly (DTE adipate), two tyrosine-derived polymers, have suitable properties for use in biomedical applications. This study reports the evaluation of the in vivo tissue response to these polymers in comparison to poly(L-lactic acid) (PLLA). Typically, the biocompatibility of a material is determined(More)
A combinatorial library of degradable polyarylates was prepared. These polymers are A-B-type copolymers consisting of an alternating sequence of a diphenol and a diacid. The library was prepared by copolymerizing, in all possible combinations, 14 different tyrosine-derived diphenols and eight different aliphatic diacids, resulting in 8 x 14 = 112 distinct(More)
Given the growing number of arthritis patients and the limitations of current treatments, there is great urgency to explore cartilage substitutes by tissue engineering. In this study, we developed a novel decellularization method for menisci to prepare acellular extracellular matrix (ECM) scaffolds with minimal adverse effects on the ECM. Among all the acid(More)
Porous three-dimensional tyrosine-derived polycarbonate (TyrPC) scaffolds with a bimodal pore distribution were fabricated to mimic bone architecture using a combination of salt-leaching and phase separation techniques. TyrPC scaffolds degraded in register with bone regeneration during the 6-week study period and compressive moduli of the scaffolds were(More)
This paper attempts to illustrate both the need for new approaches to biomaterials discovery as well as the significant promise inherent in the use of combinatorial and computational design strategies. The key observation of this Leading Opinion Paper is that the biomaterials community has been slow to embrace advanced biomaterials discovery tools such as(More)