Interdigitating cells

FIGURE 1.18 (a) Planar PLED and (b) planar PLEC in interdigitated cell configuration. 

Antigen-presenting cells (APCs) are a heterogeneous population of cells with extraordinary immunostimulatory capacity. Some play an important role in the induction of the function of T helper cells and some communicate with other lymphocytes. Cytokines can render the ability to present antigens to various cell types. This results in the expression of MHC class II molecules, which are sometimes lacking on some cells such as endothelial cells. The different types of APCs include macrophages, dendritic cells, B cells and interdigitating cells. APCs are mostly derived from bone marrow and are distributed in lymphoid tissues and in the skin. These three types of major APCs are also called professional APCs. 

In the steady state, the surface marker profile of the vast majority of the population is superficially consistent with that of mature tissue macrophages. However, closer examination reveals additional expression of markers which are generally seen only in tissue sections from central lymphoid organs, such as the murine marker NLDC145 which stains interdigitating cells (IDCs Bilyk... 

Fibroblastic meningioma Spindle cells interdigitating cell processes and desmosomes (thick collagen) (whorls)" Vimentin (-I-) EMA (S) S-100 (R) Falx, tentorium meninges choroid plexus... 

Two antiparallel helices, related by space group symmetry, are packed in an orthorhombic unit cell (Fig. 39b). There is substantial interdigitation between the helices so that side chains and main chains are linked by hydrogen bonds, such as 0-4E-0-4D (2,73 A) and 0-4D-0-3F (2.84 A) involving parallel and antiparallel strands, respectively. Plausible sites for sodium ions are near the... 

Fig. 39. (continued)—antiparallel packing arrangement of helices in the orthorhombic unit cell viewed down the c-axis shows considerable interdigitation. Hydrogen bonds (not shown) connect adjacent chains. 

Figure 1. Muscle development. A skeletal muscle fiber is formed by the fusion of many single cells (myoblasts) into a multinucleated myotube. Myotubes then develop into the muscle fiber (see text). Sarcomeres form in longitudinal structures called myofibrils. The repeating structure of the sarcomere contains interdigitating thick and thin filaments.

The inner wall of Bowman s capsule consists of specialized epithelial cells referred to as podocytes. This layer of epithelial cells is not continuous instead, the podocytes have foot-like processes that project outward. The processes of one podocyte interdigitate with the processes of an adjacent podocyte, forming narrow filtration slits. These slits provide an ample route for the filtration of fluid. 

The columnar, cuboidal basal cells are 18-20 xm in height and 8-10 iim in diameter. They form a monolayer adhered to a basement membrane by hemidesmosomes which are linked to anchoring fibrils of collagen type VII. At the lateral borders, basal cells are extensively interdigitated and joined together in places only by junctional complexes (zonula adherens), desmosomes, and gap junctions. 

An optimum relationship between the DL and the flow field channels is a key factor in the overall improvement of fhe fuel cell s performance at both high and low current densities. Currently, flow field designs are typically serpentine, interdigitated, or parallel [207,264]. The FF plate performs several functions If is a current collector, provides mechanical support for the electrodes, provides access channels for the reactants to their respective electrode surfaces and for the removal of producf water, and it prevents mixing of oxidant, fuel, and coolant fluids. 

Transparent fuel cells are also common tools used to visualize and observe the water accumulation inside FFs and on the surfaces of diffusion layers. Liu, Guo, and Ma [227] tested interdigitated and parallel flow fields wifh CFP DLs. It was observed that the former FF design enhanced the mass transfer when the gas flow was forced to pass through the DL. In fact, the water flooding areas in the interdigitated channels were substantially smaller than in the parallel channel. 

T. V. Nguyen and W. Fie. Interdigitated flow field design. In Handbook of fuel cells—Fundamentals, technology and applications, ed. W. Vielstich, H. A. Gasteiger, and A. Lamm, 325-336. New York John Wiley Sons (2003). 

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