Marginal zone lymphomas (MZLs) are a heterogeneous group of neoplasms that resemble the normal B-cell populations of the marginal zone of a lymph node. It includes three different subtypes, nodal, splenic, and extra -nodal, each, with overlapping features and yet unique characteristics. Nodal Marginal Zone lymphoma (NMZL) accounts for only 1% of all Non-Hodgkin Lymphoma (NHL). Marginal Zone lymphoma with plasmacytic differentiation is not very common. We report a unique case of Nodal marginal zone lymphoma initially presenting with lymphocytosis and lymphadenopathy, work up indicating low grade lymphoma, subsequently developing hyper viscosity syndrome due to symptomatic IgM monoclonal gammopathy. A 68 year old female was noted to have persistent leukocytosis with lymphocytic predominance after completing treatment for a urinary tract infection. Clinical exam revealed bilateral axillary adenopathy. CT scan of neck, chest, abdomen and pelvis revealed axillary, mediastinal and retroperitoneal adenopathy with splenomegaly. Chronic lymphocytic leukemia (CLL) was suspected and work up initiated. Peripheral blood Flow-cytometry revealed 24% small B-cells with surface kappa light chain restriction consistent with mature B-cell lymphoma or leukemia without typical immune phenotype of CLL. Lab reported significant elevation of total protein at 10 g/dl. Workup for para-proteinemia consistent with IgM level over 5000 mg/dl, with serum viscosity of 8. Axillary lymph node excisional biopsy reported marginal zone lymphoma with plasmacytic differentiation. Bone marrow biopsy demonstrated 42% monoclonal B-cells without co-expression of CD5 and CD23. FISH studies positive for duplication 1q and Molecular testing negative for MYDD88 mutation. Decision was made to initiate chemo therapy with R-CVP for a total of six cycles. Her treatment course was complicated by symptomatic hyper viscosity syndrome necessitating therapeutic plasmapheresis. Patient successfully completed chemo immunotherapy with normalization of blood counts, resolution of palpable adenopathy and splenomegaly. Nodal marginal lymphoma (NMZL) originates from nodal mono-cytoid or marginal zone B cells and the pathogenesis usually involves acquired mutations in oncogenes and tumor suppressor genes involving MLL2, PTTPRD, NOTCH2, and KLF2 genes. The median age is round 70 years with slight male predominance. The clinical picture varies and usually includes generalized lymphadenopathy along with B symptoms and infrequently with mild monoclonal gammopathy (any immunoglobulin subtype-IgM uncommon). Marginal Zone lymphoma with plasmacytic differentiation is not as common and shares immuno-histochemical features with lympho-plasmacytic lymphoma (LPL). They both express B cell markers CD19, CD20, and CD22) and not CD5, CD10 or CD23. Clinically, NMZL is more likely to present with prominent lymphadenopathy, while LPL can exclusively affect the marrow without extramedullary involvement. IgM levels in NMZL tend to be lower than in LPL, typically lower than 1000 mg/d. MYD88 mutation is very common in LPL, and can be seen in 10-15% NMZL. The presence of IgM monoclonal gammopathy increases the serum viscosity which can lead to serious neurologic and ophthalmologic complications. Treatment involves emergent plasmapheresis. Our case highlights a less common NHL, presenting with significant paraproteinemia and developing hyper viscosity syndrome with impressive response to plasmapheresis and chemo immunotherapy.

The main objective of this dissertation is to develop large-eddy simulation (LES) based computational tools for supersonic inlet and combustor design. In the recent past, LES methodology has emerged as a viable tool for modeling turbulent combustion. LES computes the large scale mixing process accurately, thereby providing a better starting point for small-scale models that describe the combustion process. In fact, combustion models developed in the context of Reynolds-averaged Navier Stokes (RANS) equations exhibit better predictive capability when used in the LES framework. The development of a predictive computational tool based on LES will provide a significant boost to the design of scramjet engines. Although LES has been used widely in the simulation of subsonic turbulent flows, its application to high-speed flows has been hampered by a variety of modeling and numerical issues. In this work, we develop a comprehensive LES methodology for supersonic flows, focusing on the simulation of scramjet engine components. This work is divided into three sections. First, a robust compressible flow solver for a generalized high-speed flow configuration is developed. By using carefully designed numerical schemes, dissipative errors associated with discretization methods for high-speed flows are minimized. Multiblock and immersed boundary method are used to handle scramjet-specific geometries. Second, a new combustion model for compressible reactive flows is developed. Subsonic combustion models are not directly applicable in high-speed flows due to the coupling between the energy and velocity fields. Here, a probability density function (PDF) approach is developed for high-speed combustion. This method requires solution to a high dimensional PDF transport equation, which is achieved through a novel direct quadrature method of moments (DQMOM). The combustion model is validated using experiments on supersonic reacting flows. Finally, the LES methodology is used to study the inlet-isolator component of a dual-mode scramjet. The isolator is a critical component that maintains the compression shock structures required for stable combustor operation in ramjet mode. We simulate unsteady dynamics inside an experimental isolator, including the propagation of an unstart event that leads to loss of compression. Using a suite of simulations, the sensitivity of the results to LES models and numerical implementation is studied. / text

Turbulence is ubiquitous in the flows of fluids and plasmas. This thesis is devoted to studies of the statistical properties of turbulence in the three-dimensional (3D) Hall magnetohydrodynamic (Hall-MHD) equations, the two-dimensional (2D) MHD equations, the one-dimensional (1D) hyperviscous Burgers equation, and the 3D Navier-Stokes equations. Chapter 1 contains a brief introduction to statistically homogeneous and isotropic turbulence. This is followed by an over-view of the equations we study in the subsequent chapters, the motivation for the studies and a summary of problems we investigate in chapters 2-6. In Chapter 2 we present our study of Hall-MHD turbulence [1]. We show that a shell-model version of the 3D Hall-MHD equations provides a natural theoretical model for investigating the multiscaling behaviors of velocity and magnetic structure functions. We carry out extensive numerical studies of this shell model, obtain the scaling exponents for its structure functions, in both the low-k and high-k power-law ranges of 3D Hall-MHD, and find that the extended-self-similarity procedure is helpful in extracting the multiscaling nature of structure functions in the high-k regime, which otherwise appears to display simple scaling. Our results shed light on intriguing solar-wind measurements. In Chapter 3 we present our study of the inverse-cascade regime in two-dimensional magnetohydrodynamic turbulence [2]. We present a detailed direct numerical simulation (DNS) of statistically steady, homogeneous, isotropic, two-dimensional magnetohydrodynamic (2D MHD) turbulence. Our study concentrates on the inverse cascade of the magnetic vector potential. We examine the dependence of the statistical properties of such turbulence on dissipation and friction coefficients. We extend earlier work significantly by calculating fluid and magnetic spectra, probability distribution functions (PDFs) of the velocity, magnetic, vorticity, current, stream-function, and magnetic-vector-potential fields and their increments. We quantify the deviations of these PDFs from Gaussian ones by computing their flatnesses and hyperflatnesses. We also present PDFs of the Okubo-Weiss parameter, which distinguishes between vortical and extensional flow regions, and its magnetic analog. We show that the hyperflatnesses of PDFs of the increments of the stream-function and the magnetic vector potential exhibit significant scale dependence and we examine the implication of this for the multiscaling of structure functions. We compare our results with those of earlier studies. In Chapter 4 we compare the statistical properties of 2D MHD turbulence for two different energy injection scales. We present systematic DNSs of statistically steady 2D MHD turbulence. Our two DNSs are distinguished by kinj, the wave number at which we inject energy into the system. In our first DNS (run R1), kinj = 2 and, in the second (run R2) kinj = 250. We show that various statistical properties of the turbulent states in the runs R1 and R2 are strikingly different The nature of energy spectrum, probability distribution functions, and topological structures are compared for the two runs R1 and R2 are found to be strikingly different. In Chapter 5 we study the hyperviscous Burgers equation for very high α, order of hyperviscosity [3]. We show, by using direct numerical simulations and theory, how, by increasing α in equations of hydrodynamics, there is a transition from a dissipative to a conservative system. This remarkable result, already conjectured for the asymptotic case α →∞ [U. Frisch et al., Phys. Rev. Lett. 101, 144501 (2008)], is now shown to be true for any large, but finite, value of α greater than a crossover value α crossover. We thus provide a self-consistent picture of how dissipative systems, under certain conditions, start behaving like conservative systems, and hence elucidate the subtle connection between equilibrium statistical mechanics and out-of-equilibrium turbulent flows. In Chapter 6 we show how to use asymptotic-extrapolation and Richardson extrapolation methods to extract the exponents ξ p that characterize the dependence of the order-p moments of the velocity gradients on the Reynolds number Re. To use these extrapolation methods we must have high-precision data for such moments. We obtain these high-precision data by carrying out the most extensive, quadruple precision, pseudospectral DNSs of the Navier-Stokes equation.