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The complex micrometer construct at the interface that joins the composite material to the tooth surface in restorative dentistry is composed of the composite formed by infiltrating adhesive into demineralized dentin (collagen matrix). The overall performance of composite restorations is therefore directly linked to the properties of the polymerized adhesive and adhesive-collagen composite. Nanoindentation and nanoDMA tests are performed on model methacrylate based adhesive and collagen-adhesive composite to study their mechanical properties. The adhesive collagen composite is prepared by the infiltration of dentin adhesive into a completely demineralized bovine dentin. The obtained experimental results show that both the neat adhesive and the collagen-adhesive composite are heterogeneous materials at the spatial scales of property interrogation. It is also found that the reduced elastic modulus generally decreases with increasing indentation contact depth reaching an asymptote for both neat adhesive and collagen-adhesive composite. This reduced modulus behavior can be attributed to the increase in the indentation interaction volume. In addition, the measured frequency dependent storage and loss moduli indicate that both the neat adhesive and collagen adhesive composites are viscoelastic materials which are likely to exhibit creep deformation and rate-dependent behavior in physiological function.

Vertical tilt of mesoscale eddies has been frequently observed in world oceans. The observations of composite eddies, individual eddies from an oceanic reanalysis product, and idealized numerical experiments of mesoscale eddies all show that the eddy vertical tilt is gradually increased with time in eddy mature stage, implying that the eddy translation speed changes with depth. However, eddy vertical tilt cannot be explained by the classic linear Rossby wave dispersion relation, since the classic zonal translation speed (Cx ${C}_{x}$) of linear Rossby waves is depth‐independent from the quasi‐geostrophic potential vorticity (QGPV) equation. To deduce a depth‐dependent linear Rossby wave dispersion relation, we solved the QGPV equation by assuming that the stratified water column in oceans can be separated into a number of fine layers with constant stratification in each layer, whereas the stratification changes among layers. A multi‐layer linear Rossby wave (MLRW) dispersion relation in stratified oceans is then deduced. The MLRW dispersion relation shows that Cx ${C}_{x}$ changes with depth. In each layer, Cx ${C}_{x}$ is proportional to stratification and layer thickness but inversely proportional to Earth's rotation. The estimated Cx ${C}_{x}$ structure from the MLRW dispersion relation is consistent with the Cx ${C}_{x}$ structure of eddies in numerical experiments and the observed composite eddies. Noticeably, there are some discrepancies between the theoretical estimates and those from observations and numerical simulations, primarily due to the sensitivity of the theoretical estimates to layer thickness. The study attempts to provide an approach to describe and predict mesoscale eddy vertical tilt. Plain Language Summary: Vertical tilt of mesoscale eddies has been frequently observed in world oceans. We found that the vertical tilt of mesoscale eddies is gradually increased with time in eddy mature stage from composite observed eddies, individual eddies from an oceanic reanalysis product and idealized numerical experiments. We proposed that eddy vertical tilt can be attributed to different translation speed of eddies/waves at depth. The classic linear Rossby wave theory, however, shows that the phase speed of long waves is constant with depth. To deduce depth‐dependent phase speeds of long waves, we assumed that the water column consists of a finite number of layers with constant stratification within each layer while the stratification changes among layers. A new long wave dispersion relation is deduced. The translation speed of eddies/waves from the new relation and the predicted structure of eddy vertical tilt agree well with the estimates from the composite analysis and the numerical experiments. So, the new dispersion relation is promising in predicting vertical tilt of mesoscale eddies in oceans. Key Points: The vertical tilt features of mesoscale eddies can be explained by vertical changes of translation speeds of eddies (Rossby waves)Based on the quasi‐geostrophic potential vorticity equation, a multi‐layer linear Rossby wave (MLRW) dispersion relation is deducedThe MLRW dispersion relation agrees well with the vertical tilt features of eddies in observations and numerical simulations [ABSTRACT FROM AUTHOR]

Stereotactic body radiation therapy (SBRT) and stereotactic radiosurgery (SRS) are advanced techniques capable of delivering higher doses of radiation precisely to small and complex targets. As these higher doses are delivered, the significance of patient-specific quality assurance becomes increasingly crucial to ensure both the effectiveness and safety of treatment. This study investigates the depth and field size dependence in Octavius 1000 SRS patient-specific quality assurance (PSQA), which is vital for ensuring accuracy in modern radiotherapy treatments. It comprehensively compares the performance of the Octavius 1000 SRS array against standard treatment planning system calculations, focusing on various field sizes and depths. An extensive measurement process was performed, wherein output factors were analyzed across a range of field sizes, from very small (1 × 1 cm2) to larger fields (10 × 10 cm2), at different depths (5 cm, 10 cm, and 15 cm). Our results highlighted significant variations in the measurement accuracy, dependent on the field size and depth, which underscored the challenge involved in ensuring precise dosimetry in PSQA for small fields. The largest discrepancy observed was 2.65% for a 1 × 1 cm2 field size at a depth of 15 cm. Based on these findings, a novel correction method tailored for small field sizes and varying depths was proposed. This method enhances the accuracy and reliability of PSQA in advanced radiotherapy to ensure that the delivered dose conforms closely to the planned dose, which is a critical aspect in treatments targeting small and complex tumor volumes. Through the proposed correction, this study aims to bridge the gap between calculated and measured dose distributions, thus contributing significantly to the refinement of PSQA processes in radiotherapy. • Novel PSQA correction method for Octavius 1000 SRS. • Enhanced accuracy in small field radiotherapy. • Depth and field size dependence correction method. [ABSTRACT FROM AUTHOR]

Abstract Background Ratcheting strain is produced due to the repeated accumulation of compressive strain in cartilage and may be a precursor to osteoarthritis. The aim of this study was to investigate the ratcheting behaviors of young and adult articular cartilages under cyclic compression by experiments and theoretical predictions. Methods A series of uniaxial cyclic compression tests were conducted for young and adult cartilage, and the effects of different loading conditions on their ratcheting behaviors were probed. A theoretical ratcheting model was constructed and applied to predict the ratcheting strains of young and adult cartilages with different loading conditions. Results Ratcheting strains of young and adult cartilages rapidly increased at the initial stage, followed by a slower increase in subsequent stages. The strain accumulation value and its rate for young cartilage were greater than them for adult cartilage. The ratcheting strains of the two groups of cartilage samples decreased with increasing stress rate, while they increased with increasing stress amplitude. As the stress amplitude increased, the gap between the ratcheting strains of young and adult cartilages increased gradually. The ratcheting strains of young and adult cartilages decreased along the cartilage depth from the surface to the deep layer. The ratcheting strains of different layers increased with the compressive cycle, and the difference among the three layers was noticeable. Additionally, the theoretical predictions agreed with the experimental data. Conclusions Overall, the ratcheting behavior of articular cartilage is affected by the degree of articular cartilage maturation.

• We measured soil profile CO 2 , CH 4 and N 2 O across multiple crop rotations. • Only the CO 2 concentration profile differed with crop type due to diffusivity. • The concentration gradient method underestimated CO 2 fluxes in a drought year. • We provide evidence of depth dependent CH 4 and N 2 O consumption. • CO 2 was biologically consumed in deep soil incubation. Agricultural soil emissions are a balance between sinks and sources of greenhouse gases (GHGs). The fluxes of GHGs from soils are complex and spatially and temporally heterogenous. While the soil surface is the exchange site with the atmosphere and is commonly where GHG fluxes are measured, it is important to consider processes occurring throughout the soil profile. To reduce emissions and improve agricultural sustainability we need to better understand the drivers and dynamics (production, consumption, diffusion) of these gases within the soil profile. Due to the heterogeneous nature of GHG processes at small to large scales, it is important to test how these processes differ with depth in different systems. In this study, we measured in situ CO 2 , N 2 O and CH 4 concentration gradients as a function of soil depth over subsequent maize and wheat growing seasons with active gas samplers inserted into an arable field at 10, 20, 30 and 50 cm depths. We found N 2 O and CH 4 concentrations increased with depth, but only CO 2 concentrations differed with depth between growing seasons due likely to differences in soil diffusivity driven by soil conditions. Using the concentration gradient method (GM), the CO 2 fluxes at each depth and their contribution to the surface flux were calculated and validated against a chamber method (CM) measured surface flux. We found the GM estimated surface CO 2 flux was only 6 % different in the wheat, but 28 % lower than the surface measured flux in the maize growing season, due to drought conditions reducing the accuracy of the GM. Finally, we measured fluxes of CO 2 , N 2 O and CH 4 in ambient and highly concentrated headspaces in laboratory mesocosms over a 72 h incubation period. We provide evidence of depth dependent CH 4 oxidation and N 2 O consumption and possibly CO 2 fixation. In conclusion, our study provides valuable information on the applicability of the GM and further evidence of the GHG production, consumption and diffusion mechanisms that occur deeper in the soil in a temperate arable context. [ABSTRACT FROM AUTHOR]

Owing to a variation of collagen fibres orientation through the zones of articular cartilage, it shows a depth dependent transversely isotropic mechanical behaviour. This study characterised the role of collagen fibre angle toward cartilage surface ϕ on the mechanical properties of articular cartilage with an innovative micromechanics (multi-direction composite - MDC) model. The role of collagen fibres, their volume fraction as well as angle ϕ in all zones of articular cartilage, was embedded into the MDC model. Variation of collagen fibre angle toward the cartilage surface as a function of cartilage depth was calculated. According to this function, collagen fibres are parallel to cartilage surface in superficial zone, have a nonlinear angle variation in transition zone and become perpendicular to the cartilage surface in the deep zone. The results revealed that owing to constancy of the mechanical properties of articular cartilage components and slight variation of fibres volume fraction through the depth of cartilage, variations of collagen fibre angle ϕ has the most important role in depth dependent variation of the mechanical properties of the articular cartilage. As elastic modulus parallel to cartilage surface is decreased by increasing the fibre angle qua radial elastic modulus in superficial zone is 10·2 times greater than deep zone, but elastic modulus perpendicular to cartilage surface is increased by increasing the fibre angle qua axial elastic modulus in superficial zone is 28·3 times smaller than deep zone. [ABSTRACT FROM AUTHOR]

Background: Ratcheting strain is produced due to the repeated accumulation of compressive strain in cartilage and may be a precursor to osteoarthritis. The aim of this study was to investigate the ratcheting behaviors of young and adult articular cartilages under cyclic compression by experiments and theoretical predictions.Methods: A series of uniaxial cyclic compression tests were conducted for young and adult cartilage, and the effects of different loading conditions on their ratcheting behaviors were probed. A theoretical ratcheting model was constructed and applied to predict the ratcheting strains of young and adult cartilages with different loading conditions.Results: Ratcheting strains of young and adult cartilages rapidly increased at the initial stage, followed by a slower increase in subsequent stages. The strain accumulation value and its rate for young cartilage were greater than them for adult cartilage. The ratcheting strains of the two groups of cartilage samples decreased with increasing stress rate, while they increased with increasing stress amplitude. As the stress amplitude increased, the gap between the ratcheting strains of young and adult cartilages increased gradually. The ratcheting strains of young and adult cartilages decreased along the cartilage depth from the surface to the deep layer. The ratcheting strains of different layers increased with the compressive cycle, and the difference among the three layers was noticeable. Additionally, the theoretical predictions agreed with the experimental data.Conclusions: Overall, the ratcheting behavior of articular cartilage is affected by the degree of articular cartilage maturation. [ABSTRACT FROM AUTHOR]

Numerical simulations of mantle convection with a viscoplastic rheology usually display mobile, episodic or stagnant lid regimes. In this study, we report a new convective regime in which a ridge can form without destabilizing the surrounding lithosphere or forming subduction zones. Using simulations in 2-D spherical annulus geometry, we show that a depth-dependent yield stress is sufficient to reach this ridge only regime. This regime occurs when the friction coefficient is close to the critical value between mobile lid and stagnant lid regimes. Maps of convective regime as a function of the parameters friction coefficients and depth dependence of viscosity are provided for both basal heating and mixed heating situations. The ridge only regime appears for both pure basal heating and mixed heating mode. For basal heating, this regime can occur for all vertical viscosity contrasts, while for mixed heating, a highly viscous deep mantle is required.