Liquid compound refractive X-ray lens.

We introduce the concept of a liquid compound refractive X-ray zoom lens. The lens is generated by pumping a suitable liquid lens material like water, alcohol or heated lithium through a line of nozzles each forming a jet with the cross section of lens elements. The system is housed, so there is a liquid-circulation. This lens can be used in white beam at high brilliance synchrotron sources, as radiation damages are cured by the continuous reformation of the lens. The focal length can be varied by closing nozzles, thus reducing the number of lens elements in the beam.

X-ray zoom lens allows for energy scans in X-ray microscopy.

We introduce a new design and development of a compound refractive X-ray zoom lens for energy scans in X-ray microscopy. Energy scans are, in principle, equivalent to radial scans in the reciprocal space for X-ray diffraction. Thanks to the absence of sample or detector motions, energy scans are better suited for microscopy, which requires high stability. In addition, close to the absorption edge of an element, energy scans can yield chemical information when coupled with resonant effects in full field diffraction X-ray microscopy (FFDXM) or X-ray absorption near edge structure (XANES) microscopy. Here, we demonstrate the concept by using a customized compound refractive X-ray zoom lens for 11 keV near the Ge Kα-edge. The working distance and magnification were kept constant during the energy scans by adapting the lens composition on switchable zoom lens fingers. This alleviates the need to reposition the lens while changing the energy and makes quantitative analysis more convenient for FFDXM. The fabricated zoom lens was characterized and proven suitable for the proposed measurement.

Miniaturized compound refractive X-ray zoom lens.

We introduce the concept of a miniaturized compound refractive X-ray zoom lens consisting of SU-8 lenses fabricated by deep X-ray lithography. The focal length can be varied by changing the number of lens elements placed in the beam. We use suitable actuators to move single lens elements reversibly out of the beam. The X-ray zoom lens can accept different X-ray energies while keeping a fixed working distance, or vary the focal distance for a fixed energy. The latter is useful in tuning the magnification factor in full field microscopy.

Enhanced cartilage regeneration in MIA/CD-RAP deficient mice.

Melanoma inhibitory activity/cartilage-derived retinoic acid-sensitive protein (MIA/CD-RAP) is a small soluble protein secreted from chondrocytes. It was identified as the prototype of a family of extracellular proteins adopting an SH3 domain-like fold. In order to study the consequences of MIA/CD-RAP deficiency in detail we used mice with a targeted gene disruption of MIA/CD-RAP (MIA-/-) and analyzed cartilage organisation and differentiation in in vivo and in vitro models. Cartilage formation and regeneration was determined in models for osteoarthritis and fracture healing in vivo, in addition to in vitro studies using mesenchymal stem cells of MIA-/- mice. Interestingly, our data suggest enhanced chondrocytic regeneration in the MIA-/- mice, modulated by enhanced proliferation and delayed differentiation. Expression analysis of cartilage tissue derived from MIA-/- mice revealed strong downregulation of nuclear RNA-binding protein 54-kDa (p54(nrb)), a recently described modulator of Sox9 activity. In this study, we present p54(nrb) as a mediator of MIA/CD-RAP to promote chondrogenesis. Taken together, our data indicate that MIA/CD-RAP is required for differentiation in cartilage potentially by regulating signaling processes during differentiation.

The secondary tongue of Salamandra salamandra: histochemical and ultrastructural aspects of the developing lingual epithelium.

The development of the lingual epithelium of Salamandra salamandra was investigated with emphasis on histochemical and ultrastructural aspects. The temporal and spatial occurrence and the typical appearance of various cell types; i.e. pavement cells, replacement pavement cells, basal cells, mitochondria rich cells, goblet cells and glandular cells have been analysed and documented in detail from the young larval stage up to the metamorphosed animal (2 months after metamorphosis). It is shown that anatomical re- and de novo-constructions related to the formation of the secretory tongue led to distinct changes in the cellular equipment of the epithelium of the tongue, including various histochemical properties. Finally, functional aspects of the morphological characteristics are discussed in detail and compared with respective findings in other species.

The epithelium of the tongue of Ambystoma mexicanum. Ultrastructural and histochemical aspects.

The distribution pattern of taste buds and goblet cells and histochemical and ultrastructural aspects of the tongue epithelium of Ambystoma mexicanum are here described. This study is also concerned with the developmental stages and origins of the epithelial cells. Pavement cells and goblet cells of the stratum superficiale are replaced by basal cells of the stratum germinativum in larvae and neotenous adults. The pavement cells of the larvae are characterized by a marginal layer of mucin grana. Decompaction of the mucins occurs immediately before extrusion in the adult. The larval goblet cell type (type I), which is also present in the adult, contains unfused grana of irregular shape. At the tip of the tongue, a further type (type II) of goblet cells is found. In the type II cells the intracellular secretory grana fuse to a single homogeneous mass. Leydig cells of the tongue epithelium are discerned by light microscopy first in the semi-adult, apparently correlated with partial metamorphosis. In the course of ontogenesis and induced metamorphosis the secretion changes to neutral glycoconjugates. The mucins of the pavement cells change first followed by those of the goblet cells. The glands of the secondary tongue show a dorso-ventral pattern of varying secretory qualities. Taste buds are found at the anterior margin of the tongue and along the base of the gill clasps in the early larva. They are already distributed all over the tongue at the end of the early larval phase.

The lingual epithelium of Salamandra salamandra: metamorphotic changes during its ontogenesis.

The development of the epithelia of the secondary tongue of Salamandra salamandra is described on the basis of light microscopic and scanning electron microscopic studies of defined developmental stages. A glandular area with radial ridges and furrows is formed anterior to the primary tongue during the larval phase. Epithelial cones--each a compact anlage of a gland lying in the furrows--displace the lamina propria. The glandular area grows upward and latero-caudad during metamorphosis and forms the secondary tongue by fusing with the primary tongue. Lumina within the gland anlage appear at the beginning of metamorphosis. They open as glandular tubules towards the oral cavity at the climax of metamorphosis. The epithelial lining becomes single layered and differentiates into gland cells. The glands are increasingly surrounded by fibers of the musculus genioglossus. At the orifice of the gland, the gland cells mingle with the multilayered epithelium of the surface of the tongue. This contains two types of goblet cells in addition to the villus-shaped covering cells which leave gaps for the taste buds. The goblet cells are formed before (type I) and during (type II) metamorphosis and replace the typical larval goblet cells. The new mushroom-shaped part of the secondary tongue is characterized by aborally running septae of connective tissue, visible after digestion with pankreatin. The tip of the primary tongue which originally covers the glandular part becomes completely integrated. It is characterized by crypts which become shallower caudally.

Ultrastructure and histochemical aspects of the oropharyngeal epithelium of Siren intermedia Le Conte.

The present electron microscopical and histochemical study of the oropharyngeal epithelium (OEPI) in Siren intermedia describes its various differentiated and developing cell types and cell contents. The OEPI is multilayered; it consists of a basal layer, a middle cell layer and a pavement layer. Three cell types are found in the pavement layer: pavement cells (PC), goblet cells (GC), and mitochondria-rich cells (MRC). These originate from basal cells and mature in the middle cell layer. The MRC is equipped with a tubule system that seems to be responsible for gaseous exchange. MRC and GC probably appear only in the caudal portions of the oropharynx. Electron microscopically, the goblet cell type appears uniform, except for the production of secretory granules; rostrad, these are largely PAS-positive and occipitad alcianophilic. The production of mucin granules is lower in the PC, where they accumulate as loose aggregations in the cell apex. Their contents react strongly to alcian blue. Only electron-lucent (loose) mucosubstances are exocytosed; they form the apically-situated acidic mucous coat of the PC. The possible osmoregulatory function of these mucins is discussed in relation to the model suggested by Kirschner (1982, in Gomme 1984).

Dental laminae and teeth of embryonic Ichthyophis glutinosus (L.) (Amphibia: Gymnophiona).

Light microscopic studies of dental lamina anlagen and the form and order of primary teeth were undertaken on embryos of Ichthyophis glutinosus. The palate dental lamina responsible for the dentition of the vomers and the palatine portions of the maxillopalatines develops unpaired on the lingual sides of these bones. Similarly, the upper jaw dental lamina is undivided in the rostro-median; it originates lingual to the premaxillaries. Orally paired and aborally unpaired, the dental laminae of the lower jaw are laid down along the inner sides of their respective bony anlagen. Of these, the orally undivided dental lamina corresponds to the dental portion of the caudally fused lower jaw bones while the aboral pair of dental laminae correspond to the splenial portions. When fully developed, the primary teeth are unbladed-conical and divided. They are labio-marginal, monostichous and pleurally anchored.