Microfocal X-Ray Computed Tomography Post-Processing Operations for Optimizing Reconstruction Volumes of Stented Arteries During 3D Computational Fluid Dynamics Modeling

Restenosis caused by neointimal hyperplasia (NH) remains an important clinical problem after stent implantation. Restenosis varies with stent geometry, and idealized computational fluid dynamics (CFD) models have indicated that geometric properties of the implanted stent may differentially influence NH. However, 3D studies capturing the in vivo flow domain within stented vessels have not been conducted at a resolution sufficient to detect subtle alterations in vascular geometry caused by the stent and the subsequent temporal development of NH. We present the details and limitations of a series of post-processing operations used in conjunction with microfocal X-ray CT imaging and reconstruction to generate geometrically accurate flow domains within the localized region of a stent several weeks after implantation. Microfocal X-ray CT reconstruction volumes were subjected to an automated program to perform arterial thresholding, spatial orientation, and surface smoothing of stented and unstented rabbit iliac arteries several weeks after antegrade implantation. A transfer function was obtained for the current post-processing methodology containing reconstructed 16 mm stents implanted into rabbit iliac arteries for up to 21 days after implantation and resolved at circumferential and axial resolutions of 32 and 50 μm, respectively. The results indicate that the techniques presented are sufficient to resolve distributions of WSS with 80% accuracy in segments containing 16 surface perturbations over a 16 mm stented region. These methods will be used to test the hypothesis that reductions in normalized wall shear stress (WSS) and increases in the spatial disparity of WSS immediately after stent implantation may spatially correlate with the temporal development of NH within the stented region

Population diversity and relatedness in Sugarbirds (Promeropidae: Promerops spp.)

Copyright 2018 Haworth et al. Distributed under Creative Commons CC-BY 4.0Sugarbirds are a family of two socially-monogamous passerine species endemic to southern Africa. Cape and Gurney’s Sugarbird (Promerops cafer and P. gurneyi) differ in abundance, dispersion across their range and in the degree of sexual dimorphism in tail length, factors that affect breeding systems and potentially genetic diversity. According to recent data, P. gurneyi are in decline and revision of the species’ IUCN conservation status to a threatened category may be warranted. It is therefore necessary to understand genetic diversity and risk of inbreeding in this species. We used six polymorphic microsatellite markers and one mitochondrial gene (ND2) to compare genetic diversity in P. cafer from Helderberg Nature Reserve and P. gurneyi from Golden Gate Highlands National Park, sites at the core of each species distribution. We describe novel universal avian primers which amplify the entire ND2 coding sequence across a broad range of bird orders. We observed high mitochondrial and microsatellite diversity in both sugarbird populations, with no detectable inbreeding and large effective population sizes.publishedVersio

Symptomatic HIV infection in infancy - clinical and laboratory markers of infection

Objective. To investigate the usefulness of immunological tests in the diagnosis of HIV infection in young symptomatic children < 15 months of age).Design. Tests were evaluated in HIV-infected (HIV antibody- and PCR-positive) patients and non-infected individuals.Setting. Hospitalised patients in a referral centre (Red Cross War Memorial Children's Hospital, Cape Town). Patients. All admissions under 15 months of age who had HIV antibody requested were eligible, provided there was sufficient serum (150 1-11) for further study. Overall, there were 201 symptomatic cases and 49 healthy controls. Twenty of the symptomatic cases were HIV antibody-positive and 19 of these were HIV-infected on the basis of a positive PCR for HIV viral productResults. Of the tests we evaluated (total IgG, IgM, IgA and rheumatoid factors of the same classes), raised total IgG level (cut-off 18 g/I or above) was the most useful. We used a commercial radial immunodiffusion plate which was found to have excellent reproducibility (inter-assay coefficient of variation 3.2%). The test detected 16 of 19 infected infants (sensitivity 84%, negative predictive value 98%). With the exception of the finding of oral thrush (odds ratio 7; P < 0.001), the clinical signs at presentation did not distinguish those who were HIV antibody-positive from those who were negative.Conclusions. In our study of hospital admissions, the finding of elevated IgG and HIV antibody was diagnostic of HIV infection. (The positive predictive value of the combination was 100%.) Likewise, the presence of raised IgG levels and oral candidosis had a high specificity for HIV infection (98%) but the sensitivity was low (37%).Measurement of total IgG levels by radial immunodiffusion is simple, relatively inexpensive < 10% of the cost of PGR), helpful in diagnosing HIV infection in symptomatic infants and able to be performed in areas with minimal laboratory back-up

Flavone acetic acid (FAA) with recombinant interleukin-2 (rIL-2) in advanced malignant melanoma. III: Cytokine studies.

Twelve patients undergoing IL-2 and flavone acetic acid (FAA) combination immunotherapy for advanced melanoma were studied throughout treatment for the induction of measurable levels of bioactive TNF, GM-CSF and IL-6 in their serum. This was to assess the extent of secondary cytokine induction in these patients and the possible role of such cytokines in both the toxic and therapeutic responses. The nature of the treatment schedule enabled these cytokines to be measured in response to FAA alone, FAA/IL-2 and FAA alone following IL-2/FAA activation of target cells. A small rise in the serum levels of these cytokines was seen on the initial course of FAA/IL-2 but this was minor compared to the marked elevation in levels 2-8 h following the initiation of the third course of FAA given with or without IL-2 and at a time point which coincided with maximum toxicity in those patients who experienced it. These results show that FAA alone can induce cytokine release from primed target cells. This may be associated with the therapeutic effect and/or toxicity of the agent

An in-depth case study: modelling an information barrier with Bayesian Belief Networks

We present in detail a quantitative Bayesian Belief Network (BBN) model of the use of an information barrier system during a nuclear arms control inspection, and an analysis of this model using the capabilities of a Satis ability Modulo Theory (SMT) solver. Arms control veri cation processes do not in practice allow the parties involved to gather complete information about each other, and therefore any model we use must be able to cope with the limited information, subjective assessment and uncertainty in this domain. We have previously extended BBNs to allow this kind of uncertainty in parameter values (such as probabilities) to be re ected; these constrained BBNs (cBBNs) o er the potential for more robust modelling, which in that study we demonstrated with a simple information barrier model. We now present a much more detailed model of a similar veri cation process, based on the technical capabilities and deployment concept of the UK-Norway Initiative (UKNI) Information Barrier system, demonstrating the scalability of our previously-presented approach. We discuss facets of the model itself in detail, before analysing pertinent questions of interest to give examples of the power of this approach

TRAINING FOR THE BIKE TO RUN TRANSITION IN TRIATHLON

The purpose of this study was to examine the effect of a practice regimen that targets the bike-to-run transition for triathlons; known as brick workouts. The principle of specificity suggests that since this skill is a critical transition in a triathlon, having further impact on the subsequent running section, practicing this skill is vital for success. Moreover, the identification of performance parameters that quantify a successful transition will serve to maximize practice efficiency. Subjects (N=12) performed either brick workouts or single event training, to examine their effects on the bike-run transition. Our results indicate that the brick workouts had a positive effect by eliciting an increased adaptability in knee behavior in response to the transition from cycling to running. Quicker adoption of efficient running mechanics may ensue, leading to less fatigue and greater performance

Distensibility Differs Between Sall Arteries and Veins in the Newborn Piglet Lung

BACKGROUND: We previously used micro-CT techniques to measure pulmonary artery distensibility in 3 week old piglets. Pressure/diameter relationships were measured for each artery and the slope (a) was then plotted against its diameter intercept at 0 pressure (Do). The resultant diameter independent distensibility parameter, a, was estimated by linear regression to be 1.6% per mmHg for arteries between 0.2 and 3.0 mm Do. OBJECTIVE: This study sought to determine whether; 1) distensibility of smaller arteries was similar to that of arteries with Do\u3e 0.2 mm; and 2) whether small vein and artery distensibility was similar. DESIGN/METHODS: Lower lobes were isolated and perfused with papaverine/saline to remove blood and tone. Lobar bronchi were cannulated and lobes inflated to 3 mmHg. Lobar arteries (n=13) or veins (n=12) were cannulated and perfluoroctyl bromide instilled. Small arteries (0.033 to 0.34 mm Do) and veins (0.024 to 0.33 mm Do) were imaged by planar X-ray at static pressures ranging from 21 to 3 mmHg in 3 mmHg increments. The slope of the pressure/diameter curve was estimated by linear regression (0 = Do + ~P ) for 4·8 arteries or veins per lobe. The linear relationship of all ~ vs their respective Do was plotted (0/00 = 1 + oP) to estimate distensibility. RESULTS: In small arteries, a determined by linear regression was 1.5 ± 0.1% per mmHg as previously described in larger arteries. a estimated in the same way in small veins was significantly lower at 0.9 ± 0.1% per mmHg (p \u3c 0.05). However, the X-ray images suggested that venous diameter increased more at lower than higher pressures. a estimated over the 3-9 mmHg pressure range was 1.4 ± 0.23% per mmHg. while over the 12-21 mmHg pressure range ~ was significantly lower at 0.9% ± 0.13%. CONCLUSIONS: Distensibility of the entire arterial tree over a wide range of pressures seems well described by a single, diameter independent parameter. In contrast, distensibility of small veins appears to be higher at low versus high pressures. Future studies must further examine distensibility of large and small veins at various pressures and relate the findings to pulmonary vascular hemodynamics

Proresolving and cartilage-protective actions of resolvin D1 in inflammatory arthritis

Rheumatoid arthritis (RA) is a debilitating disease characterized by persistent accumulation of leukocytes within the articular cavity and synovial tissue. Metabololipidomic profiling of arthritic joints from omega-3 supplemented mice identified elevated levels of specialized proresolving lipid mediators (SPM) including resolvin D1 (RvD1). Profiling of human RA synovial fluid revealed physiological levels of RvD1, which - once applied to human neutrophils - attenuated chemotaxis. These results prompted analyses of the antiarthritic properties of RvD1 in a model of murine inflammatory arthritis. The stable epimer 17R-RvD1 (100 ng/day) significantly attenuated arthritis severity, cachexia, hind-paw edema, and paw leukocyte infiltration and shortened the remission interval. Metabololipidomic profiling in arthritic joints revealed 17R-RvD1 significantly reduced PGE2 biosynthesis, while increasing levels of protective SPM. Molecular analyses indicated that 17R-RvD1 enhanced expression of genes associated with cartilage matrix synthesis, and direct intraarticular treatment induced chondroprotection. Joint protective actions of 17R-RvD1 were abolished in RvD1 receptor-deficient mice termed ALX/fpr2/3-/- . These investigations open new therapeutic avenues for inflammatory joint diseases, providing mechanistic substance for the benefits of omega-3 supplementation in RA

Sound Synthesis with Auditory Distortion Products

This article describes methods of sound synthesis based on auditory distortion products, often called combination tones. In 1856, Helmholtz was the first to identify sum and difference tones as products of auditory distortion. Today this phenomenon is well studied in the context of otoacoustic emissions, and the “distortion” is understood as a product of what is termed the cochlear amplifier. These tones have had a rich history in the music of improvisers and drone artists. Until now, the use of distortion tones in technological music has largely been rudimentary and dependent on very high amplitudes in order for the distortion products to be heard by audiences. Discussed here are synthesis methods to render these tones more easily audible and lend them the dynamic properties of traditional acoustic sound, thus making auditory distortion a practical domain for sound synthesis. An adaptation of single-sideband synthesis is particularly effective for capturing the dynamic properties of audio inputs in real time. Also presented is an analytic solution for matching up to four harmonics of a target spectrum. Most interestingly, the spatial imagery produced by these techniques is very distinctive, and over loudspeakers the normal assumptions of spatial hearing do not apply. Audio examples are provided that illustrate the discussion

Discovery of a 500 au protobinary in the massive prestellar core G11.92-0.61 MM2

Funding: C.J.C. acknowledges support from the University of St Andrews Restarting Research Funding Scheme (SARRF), which is funded through the SFC grant reference SFC/AN/08/020. J.D.I. acknowledges support from the UK’s STFC under ST/T000287/1. S.Z. is funded by the China Scholarship Council–University of St Andrews Scholarship (PhD programmes, No. 201806190010). T.J.H. is funded by a Royal Society Dorothy Hodgkin Fellowship.We present high-resolution ( 24.7 L⊙ for MM2E and L* > 12.6 L⊙ for MM2W. The compact sources are connected by a "bridge" of lower-surface-brightness dust emission and lie within more extended emission that may correspond to a circumbinary disk. The circumprotostellar gas mass, estimated from ~0.2" resolution VLA 0.9 cm observations assuming optically thin emission, is 6.8 ± 0.9 M⊙. No line emission is detected towards MM2E and MM2W in our high-resolution 1.3 mm ALMA observations. The only line detected is 13CO J=2-1, in absorption against the 1.3 mm continuum, which likely traces a layer of cooler molecular material surrounding the protostars. We also report the discovery of a highly asymmetric bipolar molecular outflow that appears to be driven by MM2E and/or MM2W in new deep, ~0.5" resolution (1680 au) ALMA 0.82 mm observations. This outflow, traced by low-excitation CH3OH emission, indicates ongoing accretion onto the protobinary system. Overall, the super-Alfvenic models of Mignon-Risse et al. (2021) agree well with the observed properties of the MM2E/MM2W protobinary, suggesting that this system may be forming in an environment with a weak magnetic field.Publisher PDFPeer reviewe