Compact x-ray microscope for the water window based on a high brightness laser plasma source.

We present a laser plasma based x-ray microscope for the water window employing a high-average power laser system for plasma generation. At 90 W laser power a brightness of 7.4 x 10(11) photons/(s x sr x µm(2)) was measured for the nitrogen Lyα line emission at 2.478 nm. Using a multilayer condenser mirror with 0.3 % reflectivity 10(6) photons/(µm(2) x s) were obtained in the object plane. Microscopy performed at a laser power of 60 W resolves 40 nm lines with an exposure time of 60 s. The exposure time can be further reduced to 20 s by the use of new multilayer condenser optics and operating the laser at its full power of 130 W.

Polyesteramide-derived nonwovens as innovative degradable matrices support preadipocyte adhesion, proliferation, and differentiation.

Extended soft tissue defects resulting from injuries or tumor resections are still an unresolved problem in plastic and reconstructive surgery because adequate reconstruction is difficult. Immature adipogenic precursor cells, called preadipocytes, which are located between mature adipocytes in adipose tissue, represent a powerful tool for soft tissue engineering because of their ability to proliferate and differentiate into adipose tissue after transplantation. In previous studies, we compared preadipocyte-loaded hyaluronan or collagen biomaterials and their applicability for adipose tissue engineering. Our findings demonstrated successful de novo formation of adipose tissue in vivo but pore size and stiffness were limiting factors not allowing for sufficient cell distribution in the construct. This study presents a nonwoven made of novel bioabsorbable co-poly(ester amide) based on e-caprolactam, adipic acid, and 1,4-butanediol in an innovative 3-dimensional architecture. The material was formed into nonwovens by textile manufacturing using an aerodynamic web formation process and a needle felting technique. Carriers were seeded with human preadipocytes and examined for cellular proliferation and differentiation. In addition, methods of preparing scaffolds for optimal cell interaction were evaluated. Our findings show that polyesteramide-derived nonwovens allow good adherence, proliferation, and differentiation of preadipocytes. These results are promising guidance toward an optimally designed scaffold for in vivo use.

Note: unique characterization possibilities in the ultra high vacuum scanning transmission x-ray microscope (UHV-STXM) "MAXYMUS" using a rotatable permanent magnetic field up to 0.22 T.

Using the x-ray magnetic circular dichroism effect, the soft x-ray range provides powerful detection capabilities concerning element specific structural, chemical, and magnetic properties. We present the implementation of a variable 0.22 T magnet system based on permanent magnets into the new UHV scanning microscope "MAXYMUS" at HZB/BESSY II, allowing surface sensitive and simultaneous standard transmission microscopic investigations in a variable external magnetic field. The outstanding potential of these new investigation possibilities will be demonstrated showing the development of the magnetic domain structure concurrently at the surface and in the bulk, providing a profound understanding of fundamental mechanisms in coupled magnetic systems.

[Biomechanical tests of a new scaffold for the cultivation of chondrocytes]. / Biomechanische Testung einer neuen Trägermatrix für die Kultivierung von Chondrozyten.

AIM: Scaffolds for the cultivation of chondrocytes are of increasing importance. So far, only little is known about their biomechanical properties. The present preliminary study addresses the biomechanical characteristics of a new collagen type I scaffold for the cultivation of chondrocytes. MATERIAL AND METHODS: Human chondrocytes were amplified in a monolayer and then cultivated in a 3D-scaffold over a period of up to 6 weeks. The biomechanical tests addressed the properties under uniaxial compression including stiffness and viscoelastic characteristics (creep and retardation). The obtained values were normalized against the thickness of the specimens and expressed as ratios. In addition, we present histological and quantitative PCR results (for collagen type II and aggrecan). RESULTS: The maximum force (or penetration force) revealed its highest values after a period of seven days. At this time the median value was 40 mN/mm. In the following period, a marked drop of the values was observed (19.8 mN/mm). With respect to the creep properties, we did not find any major changes over the period of six weeks. The median values were between 0.24 and 0.29 mm/mm. There were no significant differences between the samples seeded with chondrocytes and those which served as controls. A re-expansion of the samples was found with median values between 0.026 and 0.049 mm/mm (retardation). However, the original thickness was not reached after a period of 30 seconds with relief of the strain. Again, major differences of the values with respect to the duration of cultivation were not observed. Light microscopy revealed collagen type II and proteoglycans only in the pericellular region. CONCLUSION: In this study not all of the biomechanical properties of the cultivated tissue were investigated. The limitation of the tests to stiffness and viscoelastic properties was reasonable in view of a potential routine use. In addition, it may facilitate a comparison between different matrix systems. In our study, the cultivation of cells within the collagen matrix did not alter the mechanical properties of the scaffold.