Germinal center (GC) B cells cycle between the dark zone (DZ) and light zone (LZ) during antibody affinity maturation. Whether this movement is necessary for GC function has not been tested. Here we show that CXCR4-deficient GC B cells, which are restricted to the LZ, are gradually outcompeted by WT cells indicating an essential role for DZ access. Remarkably, the transition between DZ centrobl...

The Three Gorges Dam features two water-level fluctuation zones (WLFZs): the preupland drawdown zone (PU-DZ) and the preriparian drawdown zone (PR-DZ). To investigate the vegetation potential of Roegneria nutans in WLFZs, we compared the submergence tolerance and germination dynamics in the natural riparian zone (NRZ), PU-DZ and PR-DZ. We found that the NRZ seeds maintained an 81.3% intactness ...

Dilemma zone (DZ) is an area at high-speed signalized intersections, where drivers can neither cross safely nor stop comfortably at the yellow onset. The dilemma zone problem is a leading cause for crashes at high-speed signalized intersections and is therefore a pressing issue. This paper presents a novel Markov-chain-based dilemma zone protection algorithm that considers the number of vehicle...

During antibody affinity maturation, germinal center (GC) B cells cycle between affinity-driven selection in the light zone (LZ) and proliferation and somatic hypermutation in the dark zone (DZ). Although selection of GC B cells is triggered by antigen-dependent signals delivered in the LZ, DZ proliferation occurs in the absence of such signals. We show that positive selection triggered by T ce...

The germinal center (GC) reaction produces high-affinity antibodies by random mutation and selective clonal expansion of B cells with high-affinity receptors. The mechanism by which B cells are selected remains unclear, as does the role of the two anatomically defined areas of the GC, light zone (LZ) and dark zone (DZ). We combined a transgenic photoactivatable fluorescent protein tracer with m...

Introduction: Human articular cartilage (HAC) possesses a unique structure and composition with variations in matrix biochemical composition, cell morphology, cell density, cell metabolism and pericellular matrix (PCM) in discretely organized zonal architectures. The superficial zone (SZ) spans the first 10-20% of full thickness HAC. The middle zone (MZ) is about 40-60% and the deep zone (DZ) t...

Dilemma zone (DZ), also called decision zone in other literature, is an area where drivers face an indecisiveness of stopping or crossing at the yellow onset. The DZ issue is a major reason for the crashes at high-speed signalized intersections. As a result, how to prevent approaching vehicles from being caught in the DZ is a widely concerning issue. In this dissertation, the author addressed s...

Strain distribution of Al 1100 was numerically investigated during cyclic expansion extrusion (CEE) process using finite element method (FEM). Die angle, corner fillet radius and die chamber diameter were considered as die parameters and friction factor and number of passes as process parameters. The effects of these parameters were investigated on the effective strain and strain homogeneity in...

Follicular dendritic cells (FDC) in the germinal centers (GC) of secondary lymphoid organs increase the survival and proliferation of antigen-stimulated B cells and are pivotal for the affinity maturation of an antibody response and for maintenance of B cell immunological memory. The dark zone (DZ) and the light zone (LZ) constitute distinct areas of the GC containing different subtypes of FDC ...

47 Advance detection and green extension schemes are widely applied in practice as a typical 48 solution to the safety issues associated with the intersection dilemma zone (DZ) problem. Most 49 existing detector configurations were either developed based on the traditional Type I DZ model 50 in which some critical contributing factors were assumed static, or based on generic Type II DZ. 51 A co...