865 research outputs found

    The rotational spectrum of the FeD radical in its X4Δ state, measured by far-infrared laser magnetic resonance

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    Transitions between the spin-rotational levels of the FeD radical in the v = 0level of the X 4Δ ground state have been detected by the technique of laser magnetic resonance at far-infrared wavelengths. Pure-rotational transitions have been observed for the three lowest spin components. Lambda-type doubling is resolved on all the observed transitions; nuclear hyperfine structure is not observed. The energy levels of FeD are strongly affected by the breakdown of the Born–Oppenheimer approximation and cannot be modeled accurately by an effective Hamiltonian. The data are therefore fitted to an empirical formula to yield term values and g-factors for the various spin-rotational levels involved

    Fake

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    Fakes, forgery, counterfeits, hoaxes, bullshit, frauds, knock offs—such terms speak, ostensibly, to the inverse of truth or the obverse of authenticity and sincerity. But what does the modern human obsession with fabrications and frauds tell us about ourselves? And what can anthropology tell us about this obsession? This timely book is the product of the first Annual Debate of Anthropological Keywords, a collaborative project between HAU, the American Ethnological Society, and L’Homme, held each year at the American Anthropological Association Meetings. The aim of the debate is reflect critically on keywords and terms that play a pivotal and timely role in discussions of different cultures and societies, and of the relations between them. This book, with multiple authors, explodes open our common sense notions of “novelty,” “originality,” and “truth,” questioning how cultures where deception and mistrust flourish seem to produce effective, albeit opaque, forms of sociality

    Proteomic approach to identify candidate effector molecules during the in vitro immune exclusion of infective Teladorsagia circumcincta in the abomasum of sheep

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    International audienceIn the present study we have employed an in vitro organ challenge model to study the post-challenge responses in parasite naĂŻve and immune gastric tissue of sheep, in an attempt to identify the host derived factors involved in immune exclusion of Teladorsagia circumcincta larvae. Proteins present in the epithelial cells and mucus from ovine abomasa following parasite challenge in previously naĂŻve and immune animals were analysed through Matrix Assisted Laser Desorption/Ionization-Time of Flight (MALDI-Tof)-MS and shotgun proteomics. MALDI-ToF analysis of epithelial cell lysates revealed that a number of proteins identified were differentially expressed in naĂŻve and immune cells. These included intelectin and lysozymes, which were present at higher levels in epithelial cell lysates derived from immune samples. A large number of proteins were identified in the mucosal wash from immune tissue which were not present in the mucosal wash of the naĂŻve tissue. Some of these proteins were present in washes of immune tissue prior to the parasite challenge including immunoglobulin A, galectin 14 and 15 and sheep mast cell protease 1. However, other proteins, such as calcium activated chloride channel and intelectin were only detected in the washings from the challenged tissue. The latter may be related to an enhanced mucus release, which may result in entrapment of infective larvae and thus reduced establishment in tissue that has been previously challenged with the parasite. In conclusion, several proteins have been identified which may be involved, either directly or indirectly, in the exclusion and immune elimination of incoming infective larvae. In the present study, the usefulness of the in vitro model has been confirmed, and the global proteomic approach has identified proteins that had not previously been associated with parasite exclusion from abomasal mucosa, such as the calcium activated chloride channel

    Developing a virtual reality environment for petrous bone surgery: a state-of-the-art review

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    The increasing power of computers has led to the development of sophisticated systems that aim to immerse the user in a virtual environment. The benefits of this type of approach to the training of physicians and surgeons are immediately apparent. Unfortunately the implementation of “virtual reality” (VR) surgical simulators has been restricted by both cost and technical limitations. The few successful systems use standardized scenarios, often derived from typical clinical data, to allow the rehearsal of procedures. In reality we would choose a system that allows us not only to practice typical cases but also to enter our own patient data and use it to define the virtual environment. In effect we want to re-write the scenario every time we use the environment and to ensure that its behavior exactly duplicates the behavior of the real tissue. If this can be achieved then VR systems can be used not only to train surgeons but also to rehearse individual procedures where variations in anatomy or pathology present specific surgical problems. The European Union has recently funded a multinational 3-year project (IERAPSI, Integrated Environment for Rehearsal and Planning of Surgical Interventions) to produce a virtual reality system for surgical training and for rehearsing individual procedures. Building the IERAPSI system will bring together a wide range of experts and combine the latest technologies to produce a true, patient specific virtual reality surgical simulator for petrous/temporal bone procedures. This article presents a review of the “state of the art” technologies currently available to construct a system of this type and an overview of the functionality and specifications such a system requires

    The evolutionary dynamics of variant antigen genes in Babesia reveal a history of genomic innovation underlying host-parasite interaction

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    Babesia spp. are tick-borne, intraerythrocytic hemoparasites that use antigenic variation to resist host immunity, through sequential modification of the parasite-derived variant erythrocyte surface antigen (VESA) expressed on the infected red blood cell surface. We identified the genomic processes driving antigenic diversity in genes encoding VESA (ves1) through comparative analysis within and between three Babesia species, (B. bigemina, B. divergens and B. bovis). Ves1 structure diverges rapidly after speciation, notably through the evolution of shortened forms (ves2) from 5â€Č ends of canonical ves1 genes. Phylogenetic analyses show that ves1 genes are transposed between loci routinely, whereas ves2 genes are not. Similarly, analysis of sequence mosaicism shows that recombination drives variation in ves1 sequences, but less so for ves2, indicating the adoption of different mechanisms for variation of the two families. Proteomic analysis of the B. bigemina PR isolate shows that two dominant VESA1 proteins are expressed in the population, whereas numerous VESA2 proteins are co-expressed, consistent with differential transcriptional regulation of each family. Hence, VESA2 proteins are abundant and previously unrecognized elements of Babesia biology, with evolutionary dynamics consistently different to those of VESA1, suggesting that their functions are distinct

    Scientific concepts and methods for moving persistence assessments into the 21st century

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    The evaluation of a chemical substance's persistence is key to understanding its environmental fate, exposure concentration, and, ultimately, environmental risk. Traditional biodegradation test methods were developed many years ago for soluble, nonvolatile, single-constituent test substances, which do not represent the wide range of manufactured chemical substances. In addition, the Organisation for Economic Co-operation and Development (OECD) screening and simulation test methods do not fully reflect the environmental conditions into which substances are released and, therefore, estimates of chemical degradation half-lives can be very uncertain and may misrepresent real environmental processes. In this paper, we address the challenges and limitations facing current test methods and the scientific advances that are helping to both understand and provide solutions to them. Some of these advancements include the following: (1) robust methods that provide a deeper understanding of microbial composition, diversity, and abundance to ensure consistency and/or interpret variability between tests; (2) benchmarking tools and reference substances that aid in persistence evaluations through comparison against substances with well-quantified degradation profiles; (3) analytical methods that allow quantification for parent and metabolites at environmentally relevant concentrations, and inform on test substance bioavailability, biochemical pathways, rates of primary versus overall degradation, and rates of metabolite formation and decay; (4) modeling tools that predict the likelihood of microbial biotransformation, as well as biochemical pathways; and (5) modeling approaches that allow for derivation of more generally applicable biotransformation rate constants, by accounting for physical and/or chemical processes and test system design when evaluating test data. We also identify that, while such advancements could improve the certainty and accuracy of persistence assessments, the mechanisms and processes by which they are translated into regulatory practice and development of new OECD test guidelines need improving and accelerating. Where uncertainty remains, holistic weight of evidence approaches may be required to accurately assess the persistence of chemicals. Integr Environ Assess Manag 2022;18:1454-1487. © 2022 The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals LLC on behalf of Society of Environmental Toxicology & Chemistry (SETAC). Keywords: Bioavailability; Biodegradability; Biodegradation; Degradation half-lives; Persistence assessment

    Fractional exhaled nitric oxide in the assessment of exercise- induced bronchoconstriction: A multicenter retrospective analysis of UK- based athletes

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    Introduction: Exercise-induced bronchoconstriction (EIB) is not only highly prevalent in people with asthma, but can also occur independently, particularly in athletes. Fractional exhaled nitric oxide (FeNO) is an indirect biomarker of type 2 airway inflammation that has an established role in the assessment and management of asthma. The aim was to evaluate the value of FeNO in the assessment of EIB in athletes. Method: Multicenter retrospective analysis. In total, 488 athletes (male: 76%) performed baseline FeNO, and spirometry pre- and post-indirect bronchial provocation via eucapnic voluntary hyperpnea (EVH). Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were calculated for established FeNO thresholds—that is, intermediate (≄25ppb) and high FeNO (≄40ppb and≄50ppb)—and were evaluated against objective evidence of EIB (≄10% fall in FEV1). The diagnostic accuracy of FeNO was calculated using receiver operating characteristics area under the curve (ROC-AUC). Results: Thirty-nine percent of the athletes had a post-EVH fall in FEV1 consistent with EIB. FeNO values ≄25ppb, ≄40ppb, and≄50ppb were observed in 42%, 23%, and 17% of the cohort, respectively. The sensitivity of FeNO ≄25ppb was 55%, which decreased to 37% and 27% at ≄40ppb and≄50ppb, respectively. The specificity of FeNO ≄25ppb, ≄40ppb, and≄50ppb was 66%, 86%, and 89%, respectively. The ROC-AUC for FeNO was 0.656. Conclusions: FeNO ≄40ppb provides good specificity, that is, the ability to rulein a diagnosis of EIB. However, due to the poor sensitivity and predictive values, FeNO should not be employed as a replacement for indirect bronchial provocation in athletes

    Perchlorate in The Great Lakes: Isotopic Composition and Origin

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    Perchlorate is a persistent and mobile contaminant in the environment with both natural and anthropogenic sources. Stable isotope ratios of oxygen (ÎŽ^(18)O, Δ^(17)O) and chlorine (ÎŽ^(37)Cl) along with the abundance of the radioactive isotope ^(36)Cl were used to trace perchlorate sources and behavior in the Laurentian Great Lakes. These lakes were selected for study as a likely repository of recent atmospheric perchlorate deposition. Perchlorate concentrations in the Great Lakes range from 0.05 to 0.13 ÎŒg per liter. Δ^(37)Cl values of perchlorate from the Great Lakes range from +3.0‰ (Lake Ontario) to +4.0‰ (Lake Superior), whereas ÎŽ^(18)O values range from −4.1‰ (Lake Superior) to +4.0‰ (Lake Erie). Great Lakes perchlorate has mass-independent oxygen isotopic variations with positive Δ^(17)O values (+1.6‰ to +2.7‰) divided into two distinct groups: Lake Superior (+2.7‰) and the other four lakes (∌+1.7‰). The stable isotopic results indicate that perchlorate in the Great Lakes is dominantly of natural origin, having isotopic composition resembling that measured for indigenous perchlorate from preindustrial groundwaters of the western USA. The ^(36)Cl/Cl ratio of perchlorate varies widely from 7.4 × 10^(–12) (Lake Ontario) to 6.7 × 10^(–11) (Lake Superior). These ^(36)ClO_4– abundances are consistent with an atmospheric origin of perchlorate in the Great Lakes. The relatively high ^(36)ClO_4– abundances in the larger lakes (Lakes Superior and Michigan) could be explained by the presence of ^(36)Cl-enriched perchlorate deposited during the period of elevated atmospheric ^(36)Cl activity following thermonuclear bomb tests in the Pacific Ocean
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