Regularized Newton Methods for X-ray Phase Contrast and General Imaging Problems

Like many other advanced imaging methods, x-ray phase contrast imaging and tomography require mathematical inversion of the observed data to obtain real-space information. While an accurate forward model describing the generally nonlinear image formation from a given object to the observations is often available, explicit inversion formulas are typically not known. Moreover, the measured data might be insufficient for stable image reconstruction, in which case it has to be complemented by suitable a priori information. In this work, regularized Newton methods are presented as a general framework for the solution of such ill-posed nonlinear imaging problems. For a proof of principle, the approach is applied to x-ray phase contrast imaging in the near-field propagation regime. Simultaneous recovery of the phase- and amplitude from a single near-field diffraction pattern without homogeneity constraints is demonstrated for the first time. The presented methods further permit all-at-once phase contrast tomography, i.e. simultaneous phase retrieval and tomographic inversion. We demonstrate the potential of this approach by three-dimensional imaging of a colloidal crystal at 95 nm isotropic resolution.Comment: (C)2016 Optical Society of America. One print or electronic copy may be made for personal use only. Systematic reproduction and distribution, duplication of any material in this paper for a fee or for commercial purposes, or modifications of the content of this paper are prohibite

Re-expression of CD14 in response to a combined IL-10/TLR stimulus defines monocyte-derived cells with an immunoregulatory phenotype

Interleukin 10 is a central regulator of the antigen-presenting function of myeloid cells. It exerts immunomodulatory effects in vivo and induces a regulatory phenotype in monocyte-derived cells in vitro. We analyzed phenotype and function of monocytic cells in vitro in relation to the cytokine milieu and the timing of TLR-based activation. In GM-CSF/IL-4 cultured human monocytic cells, we identified two, mutually exclusive cell populations arising from undifferentiated cells: CD83$^+$ fully activated dendritic cells and CD14$^+$ macrophage like cells. Re-expression of CD14 occurs primarily after a sequential trigger with a TLR signal following IL-10 preincubation. This cell population with re-expressed CD14 greatly differs in phenotype and function from the CD83+ cells. Detailed analysis of individual subpopulations reveals that exogenous IL-10 is critical for inducing the shift toward the CD14$^+$ population, but does not affect individual changes in marker expression or cell function in most cases. Thus, plasticity of CD14 expression, defining a subset of immunoregulatory cells, is highly relevant for the composition of cellular products (such as DC vaccines) as it affects the function of the total product

Grain rotation and lattice deformation during photoinduced chemical reactions revealed by in-situ X-ray nanodiffraction

In-situ X-ray diffraction (XRD) and transmission electron microscopy (TEM) have been used to investigate many physical science phenomena, ranging from phase transitions, chemical reaction and crystal growth to grain boundary dynamics. A major limitation of in-situ XRD and TEM is a compromise that has to be made between spatial and temporal resolution. Here, we report the development of in-situ X-ray nanodiffraction to measure atomic-resolution diffraction patterns from single grains with up to 5 millisecond temporal resolution, and make the first real-time observation of grain rotation and lattice deformation during photoinduced chemical reactions. The grain rotation and lattice deformation associated with the chemical reactions are quantified to be as fast as 3.25 rad./sec. and as large as 0.5 Angstroms, respectively. The ability to measure atomic-resolution diffraction patterns from individual grains with several millisecond temporal resolution is expected to find broad applications in materials science, physics, chemistry, and nanoscience.Comment: 17 pages, 3 figure

E.U. paediatric MOG consortium consensus:Part 2 – Neuroimaging features of paediatric myelin oligodendrocyte glycoprotein antibody-associated disorders

Imaging plays a crucial role in differentiating the spectrum of paediatric acquired demyelinating syndromes (ADS), which apart from myelin oligodendrocyte glycoprotein antibody associated disorders (MOGAD) includes paediatric multiple sclerosis (MS), aquaporin-4 antibody neuromyelitis optica spectrum disorders (NMOSD) and unclassified patients with both monophasic and relapsing ADS. In contrast to the imaging characteristics of children with MS, children with MOGAD present with diverse imaging patterns which correlate with the main demyelinating phenotypes as well as age at presentation. In this review we describe the common neuroradiological features of children with MOGAD such as acute disseminated encephalomyelitis, optic neuritis, transverse myelitis, AQP4 negative NMOSD. In addition, we report newly recognized presentations also associated with MOG-ab such as the ‘leukodystophy-like’ phenotype and autoimmune encephalitis with predominant involvement of cortical and deep grey matter structures. We further delineate the features, which may help to distinguish MOGAD from other ADS and discuss the future role of MR-imaging in regards to treatment decisions and prognosis in children with MOGAD. Finally, we propose an MRI protocol for routine examination and discuss new imaging techniques, which may help to better understand the neurobiology of MOGAD.</p

Psoas abscess secondary to retroperitoneal distant metastases from squamous cell carcinoma of the cervix with thrombosis of the inferior vena cava and duodenal infiltration treated by Whipple procedure: a case report and review of the literature

Background: Psoas abscess is a rare clinical disease of various origins. Most common causes include hematogenous spread of bacteria from a different primary source, spondylodiscitis or perforated intestinal organs. But rarely some abscesses are related to malignant metastatic disease. Case presentation: In this case report we present the case of a patient with known squamous cell carcinoma of the cervix treated with radio-chemotherapy three years prior. She now presented with a psoas abscess and subsequent complete inferior vena cava thrombosis, as well as duodenal and vertebral infiltration. The abscess was drained over a prolonged period of time and later was found to be a complication caused by metastases of the cervical carcinoma. Due to the massive extent of the metastases a Whipple procedure was performed to successfully control the local progress of the metastasis. Conclusion: As psoas abscess is an unspecific disease which presents with non-specific symptoms adequate therapy may be delayed due to lack of early diagnostic results. This case report highlights the difficulties of managing a malignant abscess and demonstrates some diagnostic pitfalls that might be encountered. It stresses the necessity of adequate diagnostics to initiate successful therapy. Reports on psoas abscesses that are related to cervix carcinoma are scarce, probably due to the rarity of this event, and are limited to very few case reports. We are the first to report a case in which an extensive and complex abdominal procedure was needed for local control to improve quality of life

Superhydrophobic Terrestrial Cyanobacteria and Land Plant Transition

Plants and other organisms have evolved structures and mechanisms for colonizing land since the Early Ordovician. In this context, their surfaces, the crucial physical interface with the environment, are mainly considered barriers against water loss. It is suggested that extreme water repellency (superhydrophobicity) was an additional key innovation for the transition of algae from water to land some 400 mya. Superhydrophobicity enhances gas exchange on land and excludes aquatic competitors in water films. In a different context, in material science and surface technology, superhydrophobicity has also become one of the most important bioinspired innovations enabling the avoidance of water films and contamination. Here, we present data for an extremely water-repellent cyanobacterial biofilm of the desiccation tolerant Hassallia byssoidea providing evidence for a much earlier prokaryotic Precambrian (ca. 1–2 bya) origin of superhydrophobicity and chemical heterogeneities associated with land transition. The multicellular cyanobacterium is functionally differentiated in a submerged basal hydrophilic absorbing portion like a “rhizoid” and an upright emersed superhydrophobic “phyllocauloid” filament for assimilation, nitrogen fixation, and splash dispersed diaspores. Additional data are provided for superhydrophobic surfaces in terrestrial green algae and in virtually all ancestral land plants (Bryophytes, ferns and allies, Amborella, Nelumbo), slime molds, and fungi. Rethinking of superhydrophobicity as an essential first step for life in terrestrial environments is suggested