Entomopathogenic nematodes (EPN) (Steinernematidae and Heterorhabditidae) have a mutualistic partnership with Gram-negative Gamma-Proteobacteria in the family Enterobacteriaceae. Xenorhabdus bacteria ...are associated with steinernematids nematodes while Photorhabdus are symbionts of heterorhabditids. Together nematodes and bacteria form a potent insecticidal complex that kills a wide range of insect species in an intimate and specific partnership. Herein, we demonstrate in vivo and in vitro techniques commonly used in the rearing of these nematodes under laboratory conditions. Furthermore, these techniques represent key steps for the successful establishment of EPN cultures and also form the basis for other bioassays that utilize these organisms for research. The production of aposymbiotic (symbiont-free) nematodes is often critical for an in-depth and multifaceted approach to the study of symbiosis. This protocol does not require the addition of antibiotics and can be accomplished in a short amount of time with standard laboratory equipment. Nematodes produced in this manner are relatively robust, although their survivorship in storage may vary depending on the species used. The techniques detailed in this presentation correspond to those described by various authors and refined by P. Stock's Laboratory, University of Arizona (Tucson, AZ, USA). These techniques are distinct from the body of techniques that are used in the mass production of these organisms for pest management purposes.
Limb immobilization causes rapid declines in muscle strength and mass. Given the role of the nervous system in immobilization‐induced weakness, targeted interventions may be able to preserve muscle ...strength, but not mass, and vice versa. The purpose of this study was to assess the effects of two distinct interventions during 1 week of knee joint immobilization on muscle strength (isometric and concentric isokinetic peak torque), mass (bioimpedance spectroscopy and ultrasonography), and neuromuscular function (transcranial magnetic stimulation and interpolated twitch technique). Thirty‐nine healthy, college‐aged adults (21 males, 18 females) were randomized into one of four groups: immobilization only (n = 9), immobilization + action observation/mental imagery (AOMI) (n = 10), immobilization + neuromuscular electrical stimulation (NMES) (n = 12), or control group (n = 8). The AOMI group performed daily video observation and mental imagery of knee extensions. The NMES group performed twice daily stimulation of the quadriceps femoris. Based on observed effect sizes, it appears that AOMI shows promise as a means of preserving voluntary strength, which may be modulated by neural adaptations. Strength increased from PRE to POST in the AOMI group, with +7.2% (Cohen's d = 1.018) increase in concentric isokinetic peak torque at 30°/s. However, NMES did not preserve muscle mass. Though preliminary, our findings highlight the specific nature of clinical interventions and suggest that muscle strength can be independently targeted during rehabilitation. This study was prospectively registered: ClinicalTrials.gov NCT05072652.
What is the central question of this study?
Action observation and mental imagery (AOMI) may be a possible and potentially promising rehabilitation strategy via facilitation of neural adaptations, whereas neuromuscular electrical stimulation (NMES) may augment muscle strength and mass via peripheral mechanisms. We compared the ability of these interventions to distinctly preserve strength versus mass during one week of knee joint immobilization.
What is the main finding and its importance?
Effect sizes suggested that AOMI preserved voluntary strength, and may be used therapeutically to target neural adaptations during immobilization.
The continuing growth of the world's urban population has led to an increasing number of cities with more than 10 million inhabitants. The higher emissions of pollutants, coupled to higher population ...density, makes predictions of air quality in these megacities of particular importance from both a science and a policy perspective. Global climate models are typically run at coarse resolution to enable both the efficient running of long time integrations, and the ability to run multiple future climate scenarios. However, when considering surface ozone concentrations at the local scale, coarse resolution can lead to inaccuracies arising from the highly nonlinear ozone chemistry and the sensitivity of ozone to the distribution of its precursors on smaller scales. In this study, we use UM-UKCA, a global atmospheric chemistry model, coupled to the UK Met Office Unified Model, to investigate the impact of model resolution on tropospheric ozone, ranging from global to local scales. We focus on the model's ability to represent the probability of high ozone concentrations in the summer and low ozone concentrations, associated with polluted megacity environments, in the winter, and how this varies with horizontal resolution. We perform time-slice integrations with two model configurations at typical climate resolution (CR, ~150 km) and at a higher resolution (HR, ~40 km). The CR configuration leads to overestimation of ozone concentrations on both regional and local scales, while it gives broadly similar results to the HR configuration on the global scale. The HR configuration is found to produce a more realistic diurnal cycle of ozone concentrations and to give a better representation of the probability density function of ozone values in urban areas such as the megacities of London and Paris. We find the observed differences in model behaviour between CR and HR configurations to be largely caused by chemical differences during the winter and meteorological differences during the summer.
We report the first simultaneous quantification of Young’s modulus in the separate material phases of bone: collagen and carbonated hydroxyapatite. High-energy X-ray scattering and
in situ loading ...revealed macroscopic, mineral, and collagen Young’s moduli (90% confidence limit) for a canine fibula equaled 24.7(0.2)
GPa, 38.2(0.5)
GPa {for 00.4 and 43.6(1.4)
GPa for 22.2}, and 18(1.2)
GPa, respectively. The mineral contained compressive residual stresses on the order of −60 to −80
MPa before loading and had a stress enhancement (ratio of internal to applied stress) between 2.0 and 2.3. The diffraction peak width increased with increasing applied stress, mainly along the bone’s longitudinal direction, and peak widths returned to pre-deformation values when load was removed. In a second fibula section from the same animal, the mineral’s internal stress changed from −50
MPa (22.2 reflection) to −75
MPa (00.4) just after removal from formalin to −10
MPa after eight hours immersion in phosphate-buffered saline; the corresponding change in collagen
D-spacing Δ
D/
D equaled 4.2
×
10
−3.
Consideration of both low- and high-resolution transmission spectroscopy is key for obtaining a comprehensive picture of exoplanet atmospheres. In studies of transmission spectra, the continuum ...information is well established with low-resolution spectra, while the shapes of individual lines are best constrained with high-resolution observations. In this work, we aim to merge high- with low-resolution transmission spectroscopy to place tighter constraints on physical parameters of the atmospheres. We present the analysis of three primary transits of WASP-69 b in the visible (VIS) channel of the CARMENES instrument and perform a combined low- and high-resolution analysis using additional data from HARPS-N, OSIRIS/GTC, and WFC3/HST already available in the literature. We investigate the Na
I
D
1
and D
2
doublet, H
α
, the Ca
II
infra-red triplet (IRT), and K
I
λ
7699 Å lines, and we monitor the stellar photometric variability by performing long-term photometric observations with the STELLA telescope. During the first CARMENES observing night, we detected the planet Na
I
D
2
and D
1
lines at ~7 and ~3
σ
significance levels, respectively. We measured a D
2
/D
1
intensity ratio of 2.5 ± 0.7, which is in agreement with previous HARPS-N observations. Our modelling of WFC3 and OSIRIS data suggests strong Rayleigh scattering, solar to super-solar water abundance, and a highly muted Na feature in the atmosphere of this planet, in agreement with previous investigations of this target. We use the continuum information retrieved from the low-resolution spectroscopy as a prior to break the degeneracy between the Na abundance, reference pressure, and thermosphere temperature for the high-resolution spectroscopic analysis. We fit the Na
I
D
1
and D
2
lines individually and find that the posterior distributions of the model parameters agree with each other within 1
σ
. Our results suggest that local thermodynamic equilibrium processes can explain the observed D
2
/D
1
ratio because the presence of haze opacity mutes the absorption features.
The centra of shark vertebrae consist of cartilage mineralized by a bioapatite similar to bone's carbonated hydroxyapatite, and, without a repair mechanism analogous to remodeling in bone, these ...structures still survive millions of cycles of high-strain loading. The main structures of the centrum are an hourglass-shaped double cone and the intermedialia which supports the cones. Little is known about the nanostructure of shark centra, specifically the relationship between bioapatite and cartilage fibers, and this study uses energy dispersive diffraction (EDD) with polychromatic synchrotron x-radiation to study the spatial organization of the mineral phase and its crystallographic texture. The unique energy-sensitive detector array at beamline 6-BM-B, the Advanced Photon Source, enables EDD to quantify the texture within each sampling volume with one exposure while constructing 3D maps via specimen translation across the sampling volume. This study maps a centrum from two shark orders, a carcharhiniform and a lamniform, with different intermedialia structures. In the blue shark (Prionace glauca, Carcharhiniformes), the bioapatite's c-axes are oriented laterally within the centrum's cone walls but axially within the wide wedges of the intermedialia; the former is interpreted to resist lateral deformation, the latter to support axial loads. In the shortfin mako (Isurus oxyrinchus, Lamniformes), there is some tendency for c-axis variation with position, but the situation is unclear because one dimension of the sampling volume is considerably larger than the thickness and spacing of the intermedialia's radially-oriented lamellae. Because elastic modulus in collagen plus bioapatite mineralized tissues varies significantly with both volume fraction of bioapatite and crystallographic texture, the present 3D EDD-derived maps should inform future 3D numerical models of shark centra under applied load.
Display omitted
•Energy dispersive diffraction mapped, in 3D, bioapatite diffracted intensity/crystallographic texture in shark vertebra.•In one subvolume (cones), blue shark bioapatite c-axes were oriented laterally and elsewhere (intermedialia) axially.•The blue shark crystals appear oriented to resist lateral deformation (cone) and to support axial loads (intermedialia).•The shortfin mako’s c-axis orientation varied with position, but a relationship with microstructure was unclear.•Incorporation of EDD-derived crystallographic texture into 3D models of shark centra are discussed.
Caffeine ingestion can delay fatigue during exercise, but the mechanisms remain elusive. This study was designed to test the hypothesis that blockade of central nervous system (CNS) adenosine ...receptors may explain the beneficial effect of caffeine on fatigue. Initial experiments were done to confirm an effect of CNS caffeine and/or the adenosine A(1)/A(2) receptor agonist 5'-N-ethylcarboxamidoadenosine (NECA) on spontaneous locomotor activity. Thirty minutes before measurement of spontaneous activity or treadmill running, male rats received caffeine, NECA, caffeine plus NECA, or vehicle during four sessions separated by approximately 1 wk. CNS caffeine and NECA (intracerebroventricular) were associated with increased and decreased spontaneous activity, respectively, but caffeine plus NECA did not block the reduction induced by NECA. CNS caffeine also increased run time to fatigue by 60% and NECA reduced it by 68% vs. vehicle. However, unlike the effects on spontaneous activity, pretreatment with caffeine was effective in blocking the decrease in run time by NECA. No differences were found after peripheral (intraperitoneal) drug administration. Results suggest that caffeine can delay fatigue through CNS mechanisms, at least in part by blocking adenosine receptors.
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