Recent high angular resolution observations of protoplanetary disks at different wavelengths have revealed several kinds of structures, including multiple bright and dark rings. Embedded planets are ...the most used explanation for such structures, but there are alternative models capable of shaping the dust in rings as it has been observed. We assume a disk around a Herbig star and investigate the effect that ice lines have on the dust evolution, following the growth, fragmentation, and dynamics of multiple dust size particles, covering from 1 m to 2 m sized objects. We use simplified prescriptions of the fragmentation velocity threshold, which is assumed to change radially at the location of one, two, or three ice lines. We assume changes at the radial location of main volatiles, specifically H2O, CO2, and NH3. Radiative transfer calculations are done using the resulting dust density distributions in order to compare with current multiwavelength observations. We find that the structures in the dust density profiles and radial intensities at different wavelengths strongly depend on the disk viscosity. A clear gap of emission can be formed between ice lines and be surrounded by ring-like structures, in particular between the H2O and CO2 (or CO). The gaps are expected to be shallower and narrower at millimeter emission than at near-infrared, opposite to model predictions of particle trapping. In our models, the total gas surface density is not expected to show strong variations, in contrast to other gap-forming scenarios such as embedded giant planets or radial variations of the disk viscosity.
Measurement of serum haptoglobin (Hapto) concentrations results in only moderate reported specificity and sensitivity for the detection of metritic cows. The objective of this study was to evaluate ...associations between different variables and haptoglobin concentrations after calving. Parity, periparturient metabolic stress indicated by β-hydroxybutyric acid (BHBA) and nonesterified fatty acids (NEFA), calving difficulties, retained fetal membranes (RFM), and acute puerperal metritis (APM) were evaluated. A total of 443 Holstein Friesian cows were enrolled in this retrospective observational study. Acute puerperal metritis was diagnosed when a cow had fetid, reddish-brown, watery vaginal discharge in combination with rectal temperature ≥39.5°C. The retention of the fetal membranes has been defined as the failure to expel the fetal membranes within 12h after calving. Results of blood samples from 2 and 5 d in milk (DIM) were analyzed for Hapto, BHBA, and NEFA. Primiparous cows had a greater median Hapto concentration than multiparous cows at 5 DIM primiparous: 2.25g/L, interquartile range (IQR) 1.45–2.50, n=146; multiparous: 1.13g/L, IQR 0.52–2.22, n=302; P<0.05. Therefore, different Hapto thresholds based on references from literature for all cows (1.4g/L), primiparous cows (2.49g/L), and multiparous cows (1.4g/L) were used for further analysis. Periparturient metabolic stress indicated by elevated BHBA (≥1.2mmol/L) at 5 DIM was associated with elevated Hapto (odds ratio 2.39–2.87) regardless of parity. In contrast, elevated NEFA (≥0.6mmol/L) at 2 DIM was not a risk factor for elevated Hapto. Multiparous cows with assisted calving had a 2.46 times higher risk for elevated Hapto, whereas primiparous cows with assisted calving had no elevated risk for elevated Hapto at 5 DIM. Moreover, multiparous cows with RFM were 5.51 times more likely to have elevated Hapto at 5 DIM than cows without RFM. Acute puerperal metritis within the first 5 DIM was associated with elevated Hapto (odds ratio 2.74–5.01), regardless of parity. We speculate that the association of calving ease, RFM, and periparturient metabolic stress could explain the moderate sensitivity and specificity reported for the detection of metritic cows by measuring Hapto.
Context. The study of dynamical processes in protoplanetary disks is essential to understand planet formation. In this context, transition disks are prime targets because they are at an advanced ...stage of disk clearing and may harbor direct signatures of disk evolution. Aims. We aim to derive new constraints on the structure of the transition disk MWC 758, to detect non-axisymmetric features and understand their origin. Methods. We obtained infrared polarized intensity observations of the protoplanetary disk MWC 758 with VLT/SPHERE at 1.04 μm to resolve scattered light at a smaller inner working angle (0.093′′) and a higher angular resolution (0.027′′) than previously achieved. Results. We observe polarized scattered light within 0.53′′ (148 au) down to the inner working angle (26 au) and detect distinct non-axisymmetric features but no fully depleted cavity. The two small-scale spiral features that were previously detected with HiCIAO are resolved more clearly, and new features are identified, including two that are located at previously inaccessible radii close to the star. We present a model based on the spiral density wave theory with two planetary companions in circular orbits. The best model requires a high disk aspect ratio (H/r ~ 0.20 at the planet locations) to account for the large pitch angles which implies a very warm disk. Conclusions. Our observations reveal the complex morphology of the disk MWC 758. To understand the origin of the detected features, the combination of high-resolution observations in the submillimeter with ALMA and detailed modeling is needed.
The objective of this study was to determine minimum inhibitory concentrations (MIC) of frequently used antimicrobials for Escherichia coli and Trueperella pyogenes isolated from postpartum bovine ...uteri of cows with acute puerperal metritis (APM, n = 67), cows suspected to have APM (n = 37), and healthy cows (n = 37) and to evaluate possible differences in MIC according to clinical signs. Cows with APM had reddish-brown, fetid vaginal discharge and rectal temperature (RT) ≥39.5°C within 21 d in milk; cows suspected to have APM had either reddish-brown, fetid vaginal discharge or RT ≥39.5°C within 21 d in milk; and healthy cows had neither fetid discharge nor RT ≥39.5°C. Samples were collected from cows on commercial dairy herds (n = 7) using the cytobrush technique. A total of 37 T. pyogenes isolates and 85 E. coli isolates were tested. Ceftiofur, a third-generation cephalosporin that is often used to treat APM, was the focus of analysis. Trueperella pyogenes and E. coli were isolated more often from samples of cows with APM (46 and 90%, respectively) compared with samples from healthy cows (19 and 54%, respectively). Regarding cows suspected to have APM, T. pyogenes and E. coli were numerically more often isolated (30 and 70%, respectively) than in healthy cows (19 and 54%, respectively). Minimum inhibitory concentrations of ceftiofur were low. For T. pyogenes and E. coli, MIC50 (concentration that inhibited growth of 50% of isolates) were 0.25 and 0.5 µg/mL and MIC90 (concentration that inhibited growth of 90% of isolates) were 0.5 and 1 µg/mL, respectively. Although ceftiofur inhibited all T. pyogenes at the highest concentration tested (64 µg/mL), the growth of 5.9% of E. coli was not impaired. Recently, ampicillin has been suggested as an alternative treatment for APM. Although the T. pyogenes isolates exhibited low MIC in general (MIC50 ≤0.015 µg/mL and MIC90 = 0.06 µg/mL) and 81.1% of all T. pyogenes could be inhibited at the lowest ampicillin concentration tested, 11.8% of the E. coli isolates were not impaired at the highest concentration (64 µg/mL) tested in this study. The MIC50 and MIC90 of E. coli were 4 and ≥128 µg/mL, respectively. We detected no difference in the MIC distributions of ceftiofur or ampicillin among isolates from the 3 APM groups. In summary, E. coli with high MIC against ceftiofur as well as against ampicillin were found in this study.
The Ordovician‐Silurian transition (∼455–430 Ma) is characterized by repeated climatic perturbations, concomitant with major changes in the global oceanic redox state best exemplified by the periodic ...deposition of black shales. The relationship between the climatic evolution and the oceanic redox cycles, however, remains largely debated. Here using an ocean‐atmosphere general circulation model accounting for ocean biogeochemistry (MITgcm), we investigate the mechanisms responsible for the burial of organic carbon immediately before, during, and right after the latest Ordovician Hirnantian (445–444 Ma) glacial peak. Our results are compared with recent sedimentological and geochemical data. We show that the late Katian time slice (∼445 Ma), typified by the deposition of black shales at tropical latitudes, represents an unperturbed oceanic state, with regional organic carbon burial driven by the surface primary productivity. During the Hirnantian, our experiments predict a global oxygenation event, in agreement with the disappearance of the black shales in the sedimentary record. This suggests that deep‐water burial of organic matter may not be a tenable triggering factor for the positive carbon excursion reported at that time. Our simulations indicate that the perturbation of the ocean circulation induced by the release of freshwater, in the context of the post‐Hirnantian deglaciation, does not sustain over sufficiently long geological periods to cause the Rhuddanian (∼444 Ma) oceanic anoxic event. Input of nutrients to the ocean, through increased continental weathering and the leaching of newly exposed glaciogenic sediments, may instead constitute the dominant control on the spread of anoxia in the early Silurian.
Key Points
Up‐to‐date ocean general circulation model with biogeochemical capabilities (MITgcm)
Investigating the mechanisms responsible for the burial of organic carbon throughout the Ordovician‐Silurian boundary
Simulations suggest a global ocean oxygenation event during the latest Ordovician Hirnantian
With an enormous growth in the application of hydrophilic interaction liquid chromatography (HILIC), there has also been significant progress in HILIC method development. HILIC is a chromatographic ...method that utilises hydro-organic mobile phases with a high organic content, and a hydrophilic stationary phase. It has been applied predominantly in the determination of small polar compounds. Theoretical studies in computer-aided modelling tools, most importantly the predictive, quantitative structure retention relationship (QSRR) modelling methods, have attracted the attention of researchers and these approaches greatly assist the method development process. This review focuses on the application of computer-aided modelling tools in understanding the retention mechanism, the classification of HILIC stationary phases, prediction of retention times in HILIC systems, optimisation of chromatographic conditions, and description of the interaction effects of the chromatographic factors in HILIC separations. Additionally, what has been achieved in the potential application of QSRR methodology in combination with experimental design philosophy in the optimisation of chromatographic separation conditions in the HILIC method development process is communicated. Developing robust predictive QSRR models will undoubtedly facilitate more application of this chromatographic mode in a broader variety of research areas, significantly minimising cost and time of the experimental work.
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•Review of method development in hydrophilic interaction chromatography.•Focus on chemometric methods, particularly quantitative structure-retention relationships.•Use of computational methods for characterisation of stationary phases in hydrophilic interaction chromatography.•Application of quality by design to the optimisation of chromatographic separation in hydrophilic interaction chromatography.
High-throughput proteomics was used to determine the role of the fish liver in defense responses to bacterial infection. This was done using a rainbow trout (Oncorhynchus mykiss) model following ...infection with Aeromonas salmonicida, the causative agent of furunculosis. The vertebrate liver has multifaceted functions in innate immunity, metabolism, and growth; we hypothesize this tissue serves a dual role in supporting host defense in parallel to metabolic adjustments that promote effective immune function. While past studies have reported mRNA responses to A. salmonicida in salmonids, the impact of bacterial infection on the liver proteome remains uncharacterized in fish.
Rainbow trout were injected with A. salmonicida or PBS (control) and liver extracted 48 h later for analysis on a hybrid quadrupole-Orbitrap mass spectrometer. A label-free method was used for protein abundance profiling, which revealed a strong innate immune response along with evidence to support parallel rewiring of metabolic and growth systems. 3076 proteins were initially identified against all proteins (n = 71,293 RefSeq proteins) annotated in a single high-quality rainbow trout reference genome, of which 2433 were maintained for analysis post-quality filtering. Among the 2433 proteins, 109 showed significant differential abundance following A. salmonicida challenge, including many upregulated complement system and acute phase response proteins, in addition to molecules with putative functions that may support metabolic re-adjustments. We also identified novel expansions in the complement system due to gene and whole genome duplication events in salmonid evolutionary history, including eight C3 proteins showing differential changes in abundance.
This study provides the first high-throughput proteomic examination of the fish liver in response to bacterial challenge, revealing novel markers for the host defense response, and evidence of metabolic remodeling in conjunction with activation of innate immunity.
It has been hypothesized that predecessors of today's bryophytes significantly increased global chemical weathering in the Late Ordovician, thus reducing atmospheric CO2 concentration and ...contributing to climate cooling and an interval of glaciations. Studies that try to quantify the enhancement of weathering by non-vascular vegetation, however, are usually limited to small areas and low numbers of species, which hampers extrapolating to the global scale and to past climatic conditions. Here we present a spatially explicit modelling approach to simulate global weathering by non-vascular vegetation in the Late Ordovician. We estimate a potential global weathering flux of 2.8 (km(3) rock) yr(-1), defined here as volume of primary minerals affected by chemical transformation. This is around three times larger than today's global chemical weathering flux. Moreover, we find that simulated weathering is highly sensitive to atmospheric CO2 concentration. This implies a strong negative feedback between weathering by non-vascular vegetation and Ordovician climate.
The following research was conducted to elucidate the evolution and expression of salmonid selenoprotein P (SelP), a selenoprotein that is unique in having multiple selenocysteine (Sec) residues, ...following supranutritional selenium supplementation and infection in rainbow trout. We show that in salmonids SelP is present as four paralogues and that the diversification of SelP genes during vertebrate evolution relates to whole genome duplication events. With 17 and 16 selenocysteine residues for rainbow trout (Oncorhynchus mykiss)/Atlantic salmon (Salmo salar) SelPa1 and SelPa2 proteins respectively and 1 or 2 (trout or salmon) and 4 or 3 (trout or salmon) selenocysteine residues for salmonid SelPb1 and SelPb2 proteins respectively, this is the highest number of (predicted) multiple selenocysteine containing SelP proteins reported for any vertebrate species to date. To investigate the effects of selenium form on SelP expression we added different concentrations (1 nM- 10 μM) of organic or inorganic selenium to a trout cell line (RTG-2 cells) and analysed changes in mRNA abundance. We next studied the impact of supplementation on the potential modulation of these transcripts by PAMPs and proinflammatory cytokines in RTG-2 and RTS-11 cells. These experiments revealed that selenium type influenced the responses, and that SelP gene subfunctionalisation was apparent. To get an insight into the expression patterns in vivo we conducted a feeding trial with 2 diets differing in selenium content and 5 weeks later challenged the trout with a bacterial pathogen (Aeromonas salmonicida). Four tissues were analysed for SelP paralogue expression. The results show a significant induction of SelPa1 in gills and intestine following infection in selenium supplemented fish and for SelPa2 in gills. SelPb1 was significantly reduced in head kidney of both diet groups following infection, whilst SelPb2 was significantly upregulated in skin of both diet groups post infection. Overall these findings reveal differential expression profiles for the SelPa/SelPb paralogues in trout, influenced by selenium supply, cell type/tissue and stimulant. The increase of multiple Sec containing SelP proteins in salmonids could indicate an enhanced requirement for selenium in this lineage.
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