Extensive surgery for peritoneal tuberculosis, an ongoing diagnostic challenge in resource limited setup

Background: Peritoneal Tuberculosis is an abdominal form of Tuberculosis that affects the peritoneal cavity and enclosed organs. Clinical presentation of this rare form of extrapulmonary tuberculosis resembles that of advanced ovarian cancer and may results in unnecessary extensive surgery especially in resource limited setting. Case presentation: A case of a 36 years old prisoner who presented to us with gradual onset of abdominal distension for one-month, mild abdominal pain and noticeable progressive weight loss. Physical examination revealed she was underweight, afebrile and had a healed sub umbilical median incision scar on a glossily distended abdomen with positive fluid thrill and shifting dullness. She was HIV negative, anemic and had marked elevation of Cancer Antigen 125 marker. Abdominal ultrasound scan showed ascites with multiple cysts originating from the left iliac fossa and the abdominal pelvic CT scan showing left ovarian cyst, ascites of 3 litres and diffuse peritoneal carcinomatosis. Advanced ovarian cancer was suspected and intra-operatively 2.5 liters of straw colored ascitic fluid was found, the bowels and the omentum were covered with diffuse intestinal nodules and multiple inclusion cysts occupying the pelvic cavity. Histopathological analysis of sampled tissues revealed Peritoneal Tuberculosis. Conclusion: Peritoneal tuberculosis shares similarities in presentation to advanced ovarian cancer and should be ruled out in a woman suspected of ovarian cancer before proceeding with surgery. For proper differentiation of the two, histopathological analysis of sampled tissue through frozen section biopsy is the preferred approach in resource limited setup where laparoscopic biopsy or ultrasound guided biopsy is not feasible.

Selection Protocol for Replication in Sports and Exercise Science

Introduction: To improve the rigor of science, experimental evidence for scientific claims ideally needs to be replicated repeatedly with sufficiently similar procedures to increase the collective confidence in the veracity of those claims. Large replication projects in psychology, cancer biology and social science have evaluated the replicability of their fields but no collaborative effort has been undertaken in sports and exercise science. We propose to undertake such an effort here. As this is the first large replication project in this field, there is no agreed-upon protocol for selecting studies to replicate. Criticism of the previous selection protocols include claims they were non-randomized and non-representative, and alleged to be biased. Any selection protocol in sports and exercise science must be unbiased and representative to provide an accurate estimate of replicability of the field. The aim of this document is to produce a protocol for selecting studies to replicate for inclusion in a large replication project in sports and exercise science. Methods: The proposed selection protocol uses multiple inclusion and exclusion criteria for replication study selection, including: the year of publication and citation rankings, research disciplines, study types, the research question and key dependent variable, study methods and feasibility. Studies selected for replication will be stratified into pools based on instrumentation and expertise required and will then be allocated to volunteer laboratories for replication. Replication outcomes will be assessed using a multiple inferential strategy and descriptive information will be reported regarding the final number of included and excluded studies, and original author contact.

Pragmatic solvers for 3D Stokes and elasticity problems with heterogeneous coefficients: evaluating modern incomplete LDL^<i>T</i> preconditioners

The need to solve large saddle point systems within computational Earth sciences is ubiquitous. Physical processes giving rise to these systems include porous flow (the Darcy equations), poroelasticity, elastostatics, and highly viscous flows (the Stokes equations). The numerical solution of saddle point systems is non-trivial since the operators are indefinite. Primary tools to solve such systems are direct solution methods (exact triangular factorization) or approximate block factorization (ABF) preconditioners. While ABF solvers have emerged as the state-of-the-art scalable option, they are invasive solvers requiring splitting of pressure and velocity degrees of freedom, a multigrid hierarchy with tuned transfer operators and smoothers, machinery to construct complex Schur complement preconditioners, and the expertise to select appropriate parameters for a given coefficient regime – they are far from being “black box” solvers. Modern direct solvers, which robustly produce solutions to almost any system, do so at the cost of rapidly growing time and memory requirements for large problems, especially in 3D. Incomplete LDLT (ILDL) factorizations, with symmetric maximum weighted-matching preprocessing, used as preconditioners for Krylov (iterative) methods, have emerged as an efficient means to solve indefinite systems. These methods have been developed within the numerical linear algebra community but have yet to become widely used in applications, despite their practical potential; they can be used whenever a direct solver can, only requiring an assembled operator, yet can offer comparable or superior performance, with the added benefit of having a much lower memory footprint. In comparison to ABF solvers, they only require the specification of a drop tolerance and thus provide an easy-to-use addition to the solver toolkit for practitioners. Here, we present solver experiments employing incomplete LDLT factorization with symmetric maximum weighted-matching preprocessing to precondition operators and compare these to direct solvers and ABF-preconditioned iterative solves. To ensure the comparison study is meaningful for Earth scientists, we utilize matrices arising from two prototypical problems, namely Stokes flow and quasi-static (linear) elasticity, discretized using standard mixed finite-element spaces. Our test suite targets problems with large coefficient discontinuities across non-grid-aligned interfaces, which represent a common challenging-for-solvers scenario in Earth science applications. Our results show that (i) as the coefficient structure is made increasingly challenging, by introducing high contrast and complex topology with a multiple-inclusion benchmark, the ABF solver can break down, becoming less efficient than the ILDL solver before breaking down entirely; (ii) ILDL is robust, with a time to solution that is largely independent of the coefficient topology and mildly dependent on the coefficient contrast; (iii) the time to solution obtained using ILDL is typically faster than that obtained from a direct solve, beyond 105 unknowns; and (iv) ILDL always uses less memory than a direct solve.

Interactions between shape-persistent macromolecules as probed by AFM

Water-soluble shape-persistent cyclodextrin (CD) polymers with amino-functionalized end groups were prepared starting from diacetylene-modified cyclodextrin monomers by a combined Glaser coupling/click chemistry approach. Structural perfection of the neutral CD polymers and inclusion complex formation with ditopic and monotopic guest molecules were proven by MALDI–TOF and UV–vis measurements. Small-angle neutron and X-ray (SANS/SAXS) scattering experiments confirm the stiffness of the polymer chains with an apparent contour length of about 130 Å. Surface modification of planar silicon wafers as well as AFM tips was realized by covalent bound formation between the terminal amino groups of the CD polymer and a reactive isothiocyanate–silane monolayer. Atomic force measurements of CD polymer decorated surfaces show enhanced supramolecular interaction energies which can be attributed to multiple inclusion complexes based on the rigidity of the polymer backbone and the regular configuration of the CD moieties. Depending on the geometrical configuration of attachment anisotropic adhesion characteristics of the polymer system can be distinguished between a peeling and a shearing mechanism.

Galerkin-Eshelby Meshless Approach to Multiple Inclusion Problem

This paper presents a method of computing perturbation fields in a heterogeneous material composed of multiple ellipsoidal inclusions embedded in homogeneous matrix. The work rests on the renowned Eshelby analytical solution to the single inclusion problem. The strain perturbations, arising from this solution, are used as the shape functions in the Galerkin method, which finds the solution as a combination of these functions with minimum potential energy.