Advanced roll bite models for cold and temper rolling processes

This paper describes on-going efforts made to develop a fast and robust roll bite model for cold and temper rollingprocesses including a non-circular roll profile and a mixed lubrication model based on lubricant flow and surfaceasperity deformation models (only Coulomb friction is used in this paper however). First, the existing roll bitemodels are reviewed in details to understand their physics, their specificities, their differences and their resolutionstrategies, with a particular focus on strategies allowing for short computing time (CPU) even for heavily deformednon circular roll profiles. From this preliminary analysis, some existing strategies are selected to develop a newroll bite model. It includes in particular calculation of roll surface circumferential displacements for roll profiledetermination and an efficient relaxation technique that updates the relaxation factor dynamically at each rollstripcoupling iteration. The resulting computing time is generally less than one second (on a single processor)and convergence has been obtained for all types of cold and temper rolling conditions, from tandem mill heavyreductions to double reduction of very thin strips and to very light reduction temper rolling (< 0.5%). Simulationresults are also discussed against finite element (FE) results. Finally, it is illustrated how this new roll bite modelcan be used on an industrial database to develop accurate presets of roll force for temper mills

A Distinct Subset of Fibroblastic Stromal Cells Constitutes the Cortex-Medulla Boundary Subcompartment of the Lymph Node

The spatiotemporal regulation of immune responses in the lymph node (LN) depends on its sophisticated tissue architecture, consisting of several subcompartments supported by distinct fibroblastic stromal cells (FSCs). However, the intricate details of stomal structures and associated FSC subsets are not fully understood. Using several gene reporter mice, we sought to discover unrecognized stromal structures and FSCs in the LN. The four previously identified FSC subsets in the cortex are clearly distinguished by the expression pattern of reporters including PDGFR beta, CCL21-ser, and CXCL12. Herein, we identified a unique FSC subset expressing both CCL21-ser and CXCL12 in the deep cortex periphery (DCP) that is characterized by preferential B cell localization. This subset was clearly different from CXCL12(high) LepR(high) FSCs in the medullary cord, which harbors plasma cells. B cell localization in the DCP was controlled chiefly by CCL21-ser and, to a lesser extent, CXCL12. Moreover, the optimal development of the DCP as well as medulla requires B cells. Together, our findings suggest the presence of a unique microenvironment in the cortex-medulla boundary and offer an advanced view of the multi-layered stromal framework constructed by distinct FSC subsets in the LN

Schwannoma-like pleomorphic adenoma of the parotid

Pleomorphic adenoma is the most common benign salivary gland tumour. It can occur in any salivary gland, but is most frequently found in the parotid gland. Chondroid metaplasia is a frequent finding in pleomorphic adenoma. Other forms of metaplasia have been described, but are encountered less frequently. We report a rare case of unusual pleomorphic adenoma of the parotid gland with schwannoma-like feature

Apicotomy: a root apical fracture for surgical treatment of impacted upper canines

Impacted canines, due to systemic or local factors, represent a frequent problem in most populations. Surgical intervention usually involves exposure for spontaneous eruption, exposure for orthodontic traction or extraction. The author presents the apicotomy technique, which has been successfully used during the past twenty years for conservative intervention in cases of impacted upper canines with dilaceration or apical root-ankylosis. This original method involves surgical fracture of the root apex, followed by orthodontic traction of the corono-radicular region

The nuclear orphan receptor Nr4a2 induces Foxp3 and regulates differentiation of CD4+ T cells

Regulatory T cells (Tregs) have a central role in maintaining immune homoeostasis through various mechanisms. Although the Forkhead transcription factor Foxp3 defines the Treg cell lineage and functions, the molecular mechanisms of Foxp3 induction and maintenance remain elusive. Here we show that Foxp3 is one of the direct targets of Nr4a2. Nr4a2 binds to regulatory regions of Foxp3, where it mediates permissive histone modifications. Ectopic expression of Nr4a2 imparts Treg-like suppressive activity to naïve CD4+ T cells by inducing Foxp3 and by repressing cytokine production, including interferon-γ and interleukin-2. Deletion of Nr4a2 in T cells attenuates induction of Tregs and causes aberrant induction of Th1, leading to the exacerbation of colitis. Nr4a2-deficeint Tregs are prone to lose Foxp3 expression and have attenuated suppressive ability both in vitro and in vivo. Thus, Nr4a2 has the ability to maintain T-cell homoeostasis by regulating induction, maintenance and suppressor functions of Tregs, and by repression of aberrant Th1 induction