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Background: Adipose tissue is a primary in vivo site of inflammation in obesity. Excess visceral adipose tissue (VAT), when compared to subcutaneous adipose tissue (SAT), imparts an increased risk of obesity-related comorbidities and mortality, and exhibits differences in inflammation. Defining depot-specific differences in inflammatory function may reveal underlying mechanisms of adipose-tissue-based inflammation. Methods: Stromovascular cell fractions (SVFs) from VAT and SAT from obese humans undergoing bariatric surgery were studied in an in vitro culture system with transcriptional profiling, flow cytometric phenotyping, enzyme-linked immunosorbent assay and intracellular cytokine staining. Results: Transcriptional profiling of SVF revealed differences in inflammatory transcript levels in VAT relative to SAT, including elevated interferon- (IFN-) transcript levels. VAT demonstrated a broad leukocytosis relative to SAT that included macrophages, T cells and natural killer (NK) cells. IFN- induced a proinflammatory cytokine expression pattern in SVF and adipose tissue macrophages (ATM). NK cells, which constitutively expressed IFN-, were present at higher frequency in VAT relative to SAT. Both T and NK cells from SVF expressed IFN- on activation, which was associated with tumor necrosis factor- expression in macrophages. Conclusion: These data suggest involvement of NK cells and IFN- in regulating ATM phenotype and function in human obesity and a potential mechanism for the adverse physiologic effects of VAT.

Often the velocity measured at the rear surface of a dynamic compression target varies spatially, caused for instance by the tilt/curvature of a gas gun flyer, asymmetries in the magnetic field on a pulsed power driven experiment, or meso-scale heterogeneous targets. One way to monitor this in an experiment is to employ multiple point velocimetry techniques, but even with multiplexing this can become expensive in terms of hardware, in particular high speed sensors and scope channels. We report on the initial development of a multi-axis line-imaging VISAR system, which will record the spatial velocity along two orthogonal directions. Cylindrical optics are used to project a set of cross-hairs onto the target, maximising the use of input laser light; we then describe the image relay, interferometer configuration and alignment. This 'quasi' two dimensional system will become one of the principal diagnostics on the MACH (Mega Ampere Compression and Hydrodynamics) facility at Imperial College London, where the multi-axis measurement will help optimise strip-line design to achieve uniform ramp compression of targets.

Background X-ray imaging offers unique possibilities for Digital Image Correlation (DIC), opening the door for full-field deformation measurements of a test article in complex environments where optical DIC suffers severe biases or is impossible. While X-ray DIC has been performed in the past with standard DIC codes designed for optical images, the path-integrated nature of X-ray images places constraints on the experimental setup, predominantly that only a single surface of interest moves/deforms. These requirements are difficult to realize for many practical situations and limit the amount of information that can be garnered in a single test. Other X-ray based diagnostics such as Digital Volume Correlation (DVC) and Projection DVC (P-DVC) overcome these obstacles, but DVC is limited to quasi-static tests, and both DVC and P-DVC necessitate high-resolution computed tomography (CT) scan(s) and often require a potentially invasive pattern throughout the volume of the specimen. Objective This work presents a novel approach to measure time-resolved displacements and strains on multiple surfaces from a single series of 2D, path-integrated (PI) X-ray images, called PI-DIC. Methods The principle of optical flow or conservation of intensity—the foundation of DIC—was reframed for path-integrated images, for an exemplar setup comprised of two plates moving and deforming independently. Synthetic images were generated for rigid translations, rigid rotations, and uniform stretches, where each plate underwent a unique motion/deformation. Experimental specimens were fabricated (either an aluminum plate with tantalum features or a plastic plate with steel features) and the two specimens were independently translated. Results PI-DIC was successfully demonstrated with the synthetic images and validated with the experimental images. Prescribed displacements were recovered for each plate from the single set of path-integrated, deformed images. Errors were approximately 0.02 px for the synthetic images with 1.5% image noise, and 0.05 px for the experimental images. Conclusions These results provide the foundation for PI-DIC to measure motion and deformation of multiple, independent surfaces with subpixel accuracy from a single series of path-integrated X-ray images.