Etiologic Diagnosis of Lower Respiratory Tract Bacterial Infections Using Sputum Samples and Quantitative Loop-Mediated Isothermal Amplification

Etiologic diagnoses of lower respiratory tract infections (LRTI) have been relying primarily on bacterial cultures that often fail to return useful results in time. Although DNA-based assays are more sensitive than bacterial cultures in detecting pathogens, the molecular results are often inconsistent and challenged by doubts on false positives, such as those due to system- and environment-derived contaminations. Here we report a nationwide cohort study on 2986 suspected LRTI patients across P. R. China. We compared the performance of a DNA-based assay qLAMP (quantitative Loop-mediated isothermal AMPlification) with that of standard bacterial cultures in detecting a panel of eight common respiratory bacterial pathogens from sputum samples. Our qLAMP assay detects the panel of pathogens in 1047(69.28%) patients from 1533 qualified patients at the end. We found that the bacterial titer quantified based on qLAMP is a predictor of probability that the bacterium in the sample can be detected in culture assay. The relatedness of the two assays fits a logistic regression curve. We used a piecewise linear function to define breakpoints where latent pathogen abruptly change its competitive relationship with others in the panel. These breakpoints, where pathogens start to propagate abnormally, are used as cutoffs to eliminate the influence of contaminations from normal flora. With help of the cutoffs derived from statistical analysis, we are able to identify causative pathogens in 750 (48.92%) patients from qualified patients. In conclusion, qLAMP is a reliable method in quantifying bacterial titer. Despite the fact that there are always latent bacteria contaminated in sputum samples, we can identify causative pathogens based on cutoffs derived from statistical analysis of competitive relationship

Non-conservative effects on spinning black holes from world-line effective field theory

Abstract We generalize the worldline EFT formalism developed in [4–9] to calculate the non-conservative tidal effects on spinning black holes in a long wavelength approximation that is valid to all orders in the magnitude of the spin. We present results for the rate of change of mass and angular momentum in a background field and find agreement with previous calculations obtained by different techniques. We also present new results for both the non-conservative equations of motion and power loss/gain for a binary inspiral, which start at 5PN and 2.5PN order respectively and manifest the Penrose process

Approximation of bivariate copulas by patched bivariate Fréchet copulas

Bivariate Fréchet (BF) copulas characterize dependence as a mixture of three simple structures: comonotonicity, independence and countermonotonicity. They are easily interpretable but have limitations when used as approximations to general dependence structures. To improve the approximation property of the BF copulas and keep the advantage of easy interpretation, we develop a new copula approximation scheme by using BF copulas locally and patching the local pieces together. Error bounds and a probabilistic interpretation of this approximation scheme are developed. The new approximation scheme is compared with several existing copula approximations, including shuffle of min, checkmin, checkerboard and Bernstein approximations and exhibits better performance, especially in characterizing the local dependence. The utility of the new approximation scheme in insurance and finance is illustrated in the computation of the rainbow option prices and stop-loss premiums.Bivariate Frechet copulas Patched bivariate Frechet copula Approximation of bivariate copulas Rainbow options

First-principles investigations of arsenate doping into the ettringite lattice

Hazardous wastes are commonly immobilized using cementitious materials. Ettringite (Ca6Al2(OH)12(SO4)3∙26H2O) is one of the main components of hydrated cement and is known to stabilize anionic species. Thus, it is a promising material for the stabilization of arsenate (As(V)) in cementitious waste streams. However, the effects of As(V) incorporation into the ettringite structure on the structural properties of As and ettringite remain unclear. Herein, As(V) doping into the structure of ettringite was investigated based on the first-principles calculations using density functional theory (DFT), and the results suggested that the mechanism involving the substitution of AsO4 3− by SO4 2− was energetically favorable and that As doping increased the total bond order of ettringite, leading to a more stable structure. The elastic properties and anisotropy of ettringite and As-doped ettringite were also investigated using DFT calculations. The results showed that the mechanical properties of the As-doped ettringite structure were stable according to Born's criterion. Moreover, As doping increased the elastic constants and elastic modulus of ettringite but reduced its elastic anisotropy. These results provide valuable insights into the long-term stabilization of As species and their migration in cementitious wastes.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Rivers, Ports, Waterways and Dredging Engineerin

Immobilization capacity assessment of a binder from arsenic-containing biohydrometallurgy waste: Effects of halloysite nanotubes and biochar addition

The aim of this study was to improve the immobilization capacity of a binder prepared from As-containing biohydrometallurgy waste (BAW) on arsenic (As) by modifying it with halloysite nanotubes (HNTs) and biochar (BC). The study investigated the influence of HNTs and BC on the chemical fractions and leaching characteristics of As, as well as the influence on the compressive strength of BAW. The results indicated that the addition of HNTs and BC effectively decreased As leaching. The presence of 1.0 wt% HNTs decreased the As leaching concentration from 1.08 mg/L to 0.15 mg/L, with the corresponding immobilization rate reaching about 90.9 %. A high amount of BC seemed to show better performance in improving the As immobilization capacity of BAW. However, a strongly reduced early compressive strength of BAW was observed, making it unsuitable to be used as an additive in this situation. The effects of HNTs on the increase of As immobilization capacity of BAW were attributed to two aspects. Firstly, As species were adsorbed onto the surface of HNTs via H-bonds, which was verified via density functional theory calculation. Secondly, the addition of HNTs decreased the pore volume of BAW, leading to a more compact structure, and hence increasing the physical encapsulation capacity for As. Environmental implication: The rational disposal of arsenic-containing biohydrometallurgy waste has always been a top priority for the green and low-carbon development of the metallurgical industry. In this article, we have taken the perspective of large-scale resource utilization of solid waste and pollution control, and developed arsenic-containing biohydrometallurgy waste into a cementitious material, and enhancing arsenic immobilization capacity with the addition of HNTs and BC. This study provides an effective method for the rational disposal of arsenic-containing biohydrometallurgy waste.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Rivers, Ports, Waterways and Dredging Engineerin