Naturally occurring coinfections of pathogens have been reported in salmonids, but their consequences on disease resistance are unclear. We hypothesized that 1) coinfection of Caligus rogercresseyi ...reduces the resistance of Atlantic salmon to Piscirickettsia salmonis; and 2) coinfection resistance is a heritable trait that does not correlate with resistance to a single infection.
In total, 1,634 pedigreed Atlantic salmon were exposed to a single infection (SI) of P. salmonis (primary pathogen) or coinfection with C. rogercresseyi (secondary pathogen). Low and high level of coinfection were evaluated (LC = 44 copepodites per fish; HC = 88 copepodites per fish). Survival and quantitative genetic analyses were performed to determine the resistance to the single infection and coinfections.
C. rogercresseyi significantly increased the mortality in fish infected with P. salmonis (SI mortality = 251/545; LC mortality = 544/544 and HC mortality = 545/545). Heritability estimates for resistance to P. salmonis were similar and of medium magnitude in all treatments (h2SI = 0.23 ± 0.07; h2LC = 0.17 ± 0.08; h2HC = 0.24 ± 0.07). A large and significant genetic correlation with regard to resistance was observed between coinfection treatments (rg LC-HC = 0.99 ± 0.01) but not between the single and coinfection treatments (rg SI-LC = -0.14 ± 0.33; rg SI-HC = 0.32 ± 0.34).
C. rogercresseyi, as a secondary pathogen, reduces the resistance of Atlantic salmon to the pathogen P. salmonis. Resistance to coinfection of Piscirickettsia salmonis and Caligus rogercresseyi in Atlantic salmon is a heritable trait. The absence of a genetic correlation between resistance to a single infection and resistance to coinfection indicates that different genes control these processes. Coinfection of different pathogens and resistance to coinfection needs to be considered in future research on salmon farming, selective breeding and conservation.
Periodically patterned metamaterials are known for exhibiting wave properties similar to the ones observed in electronic band structures in crystal lattices. In particular, periodic ferromagnetic ...materials are characterized by the presence of bands and band gaps in their spin-wave spectrum at tunable GHz frequencies. Recently, the fabrication of magnets hosting Dzyaloshinskii-Moriya interactions has been pursued with high interest since properties, such as the stabilization of chiral spin textures and nonreciprocal spin-wave propagation, emerge from this antisymmetric exchange coupling. In this context, to further engineer the magnon band structure, we propose the implementation of magnonic crystals with periodic Dzyaloshinskii-Moriya interactions, which can be obtained, for instance, via patterning of periodic arrays of heavy metal wires on top of an ultrathin magnetic film. We demonstrate through theoretical calculations and micromagnetic simulations that such systems show an unusual evolution of the standing spin waves around the gaps. We also predict the emergence of indirect gaps and flat bands, effects that depend on the strength of the Dzyaloshinskii-Moriya interaction. Such phenomena, which have been previously observed in different systems, are observed here simultaneously, opening new routes towards engineered metamaterials for spin-wave-based devices.
Abstract Objective To analyse the impact of liver resection (LR) in patients with Hepatocellular Carcinoma (HCC) within the Barcelona-Clinic-Liver-Cancer (BCLC)-B stage. Methods Analysis of patients ...with BCLC-B HCC treated with LR or transarterial chemoembolization (TACE) between 2007 and 2012 in our hospital. Survival/recurrence analyses were performed by log-rank tests and Cox multivariate models. Further analyses were specifically obtained for the HCC subclassification (B1–2–3–4) proposed recently. Results Eighty patients were treated (44-TACE/36-LR). Number of nodules was 1.8(1.1), being multinodular in 50% of cases. Although resected patients had a higher hospital stay than those who underwent TACE (14 ± 13 vs 7 ± 6; P = 0.004), the rate and severity of complications was lower measured by Dindo–Clavien scale (P < 0.05). Overall survival was 40% with a median follow-up of 29.5 months (0.07–96.9). Five-years survival rates were 62.9%, 28.1% and 15.4%, respectively (P = 0.004) for B1, B2 and B3–4 stages. Cox model showed that only total bilirubin OR = 2.055(1.23–3.44) and BCLC subclassification B3–4 OR = 2.439(1.04–5.7) and B2 OR = 2.79(1.35–5.77) vs B1 were independent predictors of 5-years-survival. In B1 patients, surgical approach led a significant decrease in 5-years recurrence-rate (25% vs 60%; P = 0.018). In the surgical subgroup analysis, better results were observed if well/moderate differentiation combined with no microvascular-invasion (VI) in 5-years-survival (84.6%; P = 0.001) and -recurrence (23.1%; P = 0.041), respectively. These survival and recurrence trends were remarkable in B1 stages. Conclusions Management of Intermediate BCLC-B HCC stage should be more complex and include updated criteria regarding B-stage subclassifications, VI and tumour differentiation. Modern surgical resection would offer improved survival benefit with acceptable safety in selected BCLC-B stage patients.
Exotic plant invasions can notably alter the nitrogen (N) cycle of ecosystems. However, there is large variation in the magnitude and direction of their impact that remains unexplained. We present a ...structured meta‐analysis of 100 papers, covering 113 invasive plant species with 345 cases of invasion across the globe and reporting impacts on N cycle‐related metrics. We aim to explain heterogeneity of impacts by considering methodological aspects, properties of the invaded site and phylogenetic and functional characteristics of the invaders and the natives. Overall, plant invasions increased N pools and accelerated fluxes, even when excluding N‐fixing invaders. The impact on N pools depended mainly on functional differences and was greater when the invasive plants and the natives differed in N‐fixation ability, plant height and plant/leaf habit. Furthermore, the impact on N fluxes was related mainly to climate, being greater under warm and moist conditions. Our findings show that more functionally distant invaders occurring in mild climates are causing the strongest alterations to the N cycle.
Vaccination is considered crucial for disease prevention and fish health in the global salmon farming industry. Nevertheless, some aspects, such as the efficacy of vaccines, can be largely ...circumvented during natural coinfections. Sea lice are ectoparasitic copepods that can occur with a high prevalence in the field, are frequently found in co-infection with other pathogens, and are highly detrimental to fish health. The aim of this case-control study was to evaluate the interaction between the detrimental effects of coinfection and the protective effects of vaccination in fish. We used the interaction between the sea louse Caligus rogercresseyi, the bacterial pathogen Piscirickettsia salmonis, and their host, the Atlantic salmon Salmo salar, as a study model. Our results showed that coinfection decreased the accumulated survival (AS) and specific growth rate (SGR) of vaccinated fish (AS = 5.2 ± 0.6%; SGR = -0.05 ± 0.39%) compared to a single infection of P. salmonis (AS = 42.7 ± 1.3%; SGR = 0.21 ± 0.22%). Concomitantly, the bacterial load and clinical signs of disease were significantly increased in coinfected fish. Coinfection may explain the reduced efficacy of vaccines in sea cages and highlights the need to test fish vaccines in more diverse conditions rather than with a single infection.
It is now common practice to perform collocated DC resistivity and seismic refraction surveys that complement each other in the search for more accurate characterization of the subsurface. Although ...conventional separate DC resistivity and seismic models can be diagnostic, we posit that better results can be derived from jointly estimated models. We make the assumption that both methods must be sensing the same underlying geology and have developed an innovative resistivity‐velocity cross‐gradients relationship to evaluate the structural features common to both methods. The cross‐gradients function is incorporated as a constraint in a nonlinear least squares problem formulation, which is solved using the Lagrange multiplier method. The resultant iterative two‐dimensional (2‐D) joint inversion scheme is successfully applied to synthetic data (serving as validation tests here) and to field data from collocated DC resistivity and seismic refraction profiling experiments and also compared to conventional separate inversion results. The joint inversion results are shown to be superior to those from separate 2‐D inversions of the respective data sets, since our algorithm leads to resistivity and velocity models with remarkable structural agreement.
Abstract
Submolecular charge distribution significantly affects the physical-chemical properties of molecules and their mutual interaction. One example is the presence of a π-electron-deficient ...cavity in halogen-substituted polyaromatic hydrocarbon compounds, the so-called π-holes, the existence of which was predicted theoretically, but the direct experimental observation is still missing. Here we present the resolution of the π-hole on a single molecule using the Kelvin probe force microscopy, which supports the theoretical prediction of its existence. In addition, experimental measurements supported by theoretical calculations show the importance of π-holes in the process of adsorption of molecules on solid-state surfaces. This study expands our understanding of the π-hole systems and, at the same time, opens up possibilities for studying the influence of submolecular charge distribution on the chemical properties of molecules and their mutual interaction.
PDF
