Cap Model Research Articles

Degradation of Dynamic Parameters of Reinforced Concrete Buildings during an Earthquake

The article presents the results of a numerical study of the effect of local damage to load-bearing structures on the dynamic characteristics during an earthquake. The studies were carried out in the LS-DYNA software package, which implemented the nonlinear concrete model, Continuous Surface Cap Model (CSCM). The computational model of the building uses solid finite elements for concrete and bar elements for reinforcing bars. As the object of modelling, a 1-storey building with a frame structural layout was chosen. Studies have shown that during an earthquake with an intensity of 7 points, specified by the corresponding accelerogram, there is no change in natural frequencies, that is, the damage resulting from this earthquake is insignificant. During an earthquake with an intensity of 8 points, a significant (up to 55 %) reduction in natural frequencies occurs. This suggests that the structure is damaged, and the overall stiffness of the building is reduced. Analysis of the results shows that the most intense decrease in natural frequencies occurs in the active phase of an earthquake. After the end of the active phase, the frequencies stabilize and stop falling. The LS-DYNA software package enables to perform studies of the effect of local damage of the load-bearing structures on the dynamic characteristics during an earthquake with the direct reinforcement of concrete with reinforcing bars and can be used in the calculations and the design of buildings and structures.

An experimental and numerical study of reinforced conventional concrete and ultra-high performance concrete columns under lateral impact loads

This paper presents an experimental and numerical study on the dynamic behaviour of axially-loaded reinforced conventional concrete (RC) and ultra-high performance concrete (UHPC) columns against low-velocity impact loading. The test specimens were divided into two groups with square and circular cross-section shapes, and each group includes both RC and UHPC columns. The impact scenario was modelled with a drop weight falling freely on the column mid-span. Brittle failure with shear plug formation was observed in RC columns while UHPC columns remained a flexure response with minimal damage under severe impact loads. To further interpret the experimental data, detailed finite element (FE) models were developed for RC and UHPC columns. A Continuous Surface Cap Model (CSCM) which accounts for the triaxial material strength, post peak softening and strain rate effect was adopted for UHPC material. After validating the material and structural model based on the testing data, extensive numerical simulations were performed to predict the UHPC column residual loading capacity after lateral impacts. Impact mass-velocity (M-V) diagrams were derived for the UHPC column damage assessment, and analytical formulae which could be easily applied to generate M-V diagrams were derived based on parametric studies.

The co-importance of physical mixing and biogeochemical consumption in controlling water cap oxygen levels in Base Mine Lake

Bitumen extraction in the Athabasca oil sands region of Alberta Canada has resulted in 1 billion m3 of tailings. Base Mine Lake (BML), the first commercial-scale pit lake (PL) in the Alberta oil sands, is currently being assessed as a potential fluid fine tailings (FFT) reclamation strategy. Here, field-based, BML water cap depth-dependent oxygen consumption rate (OCR) determination, geochemical characterization and modelling of physical mixing were combined to identify the key processes driving the oxygen mass balance and distribution. The highest OCR values (66.9 ± 5.9 O2/m2/d) occurred at the FFT water interface and were driven by dissolved methane and ammonia concentrations. Given the extensive mass of these reductants within the FFT, their biogeochemical redox cycling is anticipated to impact BML oxygen concentrations for decades. The integration of OCR and modelling results revealed the importance of physical mixing as a mechanism to maintain an oxic hypolimnion and FFT water interface. The oxygen mass balance indicates that without the physical movement of oxygen into the hypolimnion, the OCR values currently observed would result in anoxia in the lower 3.5 m of the BML water cap, migrating upwards of the oxic-anoxic boundary and enabling the generation of new oxygen-consuming constituents directly within the water cap through anaerobic redox transformations. Results here guide the development and application of water-capped tailings as a reclamation strategy for not only the oil sands industry, but also for other anthropogenically impacted or engineered systems with high oxygen demand.

Vehicle routing analyses with integrated order picking and delivery problem under carbon cap and trade policy

PurposeThe purpose of this study is to model a vehicle routing problem with integrated picking and delivery under carbon cap and trade policy. This study also provides sensitivity analyses of carbon cap and price to the total cost.Design/methodology/approachA mixed integer linear programming (MILP) model is formulated to model the vehicle routing with integrated order picking and delivery constraints. The model is then solved by using the CPLEX solver. Carbon footprint is estimated by a fuel consumption function that is dependent on two factors, distance and vehicle speed. The model is analyzed by considering 10 suppliers and 20 customers. The distance and vehicle speed data are generated using simulation with random numbers.FindingsSignificant amount of carbon footprint can be reduced through the adoption of eco-efficient vehicle routing with a marginal increase in total transportation cost. Sensitivity analysis indicates that compared to carbon cap, carbon price has more influence on the total cost.Research limitations/implicationsThe model considers mid-sized problem instances. To analyze large size problems, heuristics and meta-heuristics may be used.Practical implicationsThis study provides an analysis of carbon cap and price model that would assist practitioners and policymakers in formulating their policy in the context of carbon emissions.Originality/valueThis study provides two significant contributions to low carbon supply chain management. First, it provides a vehicle routing model under carbon cap and trade policy. Second, it provides a sensitivity analysis of carbon cap and price in the model.

X-ray light curves from realistic polar cap models: inclined pulsar magnetospheres and multipole fields

ABSTRACT Thermal X-ray emission from rotation-powered pulsars is believed to originate from localized ‘hotspots’ on the stellar surface occurring where large-scale currents from the magnetosphere return to heat the atmosphere. Light-curve modelling has primarily been limited to simple models, such as circular antipodal emitting regions with constant temperature. We calculate more realistic temperature distributions within the polar caps, taking advantage of recent advances in magnetospheric theory, and we consider their effect on the predicted light curves. The emitting regions are non-circular even for a pure dipole magnetic field, and the inclusion of an aligned magnetic quadrupole moment introduces a north–south asymmetry. As the quadrupole moment is increased, one hotspot grows in size before becoming a thin ring surrounding the star. For the pure dipole case, moving to the more realistic model changes the light curves by $5\!-\!10{{\, \rm per\, cent}}$ for millisecond pulsars, helping to quantify the systematic uncertainty present in current dipolar models. Including the quadrupole gives considerable freedom in generating more complex light curves. We explore whether these simple dipole+quadrupole models can account for the qualitative features of the light curve of PSR J0437−4715.

Free vibration of spherical cap subjected to various boundary conditions

In this article, the free vibration characteristics of spherical caps with different thickness distribution subjected to general boundary conditions are investigated using a semi-analytical approach. Based on the theory of thin shell, the theoretical model of spherical cap is established. Spherical caps are partitioned into sections along the meridional orientation. The displacement components of spherical caps along the meridional direction are represented by Jacobi polynomials. Meanwhile, Fourier series are utilized to express displacement components in the circumferential direction. Various boundary conditions can be easily achieved by the penalty method of the spring stiffness technique. The vibration characteristics of spherical caps are derived by means of the Rayleigh–Ritz energy method. Reliability and validity of the current method are verified by convergence studies and numerical verification. The comparison of results between the current method, finite element method, and those published in the literature prove that the current method works well when handling free vibration of spherical caps. More results of spherical caps with different geometric specifications and edge conditions are displayed in the form of table and graphic, which may serve as a reference for future studies.

Consolidation and Simulations of Hot Isostatic Pressing of Selective Laser Sintered Stainless Steel Parts

The method of hot isostatic pressing of selective laser sintered parts is proposed to make metal parts with complex structure and high density. The forming process is greatly simplified by removing the operation of cold isostatic pressing. Therefore, it is a new effective method for manufacturing complex metal parts. A bevel gear has been made by this method using AISI304 stainless steel. The simulation of hot isostatic pressing has been carried out using the Drucker–Prager–Cap model in ABAQUS/Standard and the hyperbolic-sine creep subroutine. The simulation results have been compared with those of the experiments. The final relative density of the parts by this method increases up to 0.90 from original 0.37. The results show that there is only big volumetric contraction without obvious distortions. The errors of the main dimensions are within 6%, which indicates good agreement between the experimental results and the calculated results.

Study of Compaction of the Titanium Powder by the Experimental-Analytical Method

The dependence of porosity θ of the spongy titanium-based powder material on stress state coefficient k during the plastic deformation with the prevailing effect of the uniform compression is investigated. Based on the results found in previous works, the family of yield curves with a variable porosity is plotted on the σ–T plane. The yield criterion of the powder material is based on the Modified Drucker–Prager Cap Model. Straight lines corresponding to various values of stress-state coefficient k = σ/T, where σ is the average hydrostatic stress and T is the intensity of tangential stresses, are represented in the graph of the geometric interpretation of the accepted plasticity model. To formulate the relation of porosity (θ, %), average normal stress ( $$\bar {\sigma }$$ ), expressed in the dimensionless form, and stress-state coefficient k, intersection points of the family of curves corresponding to generatrices of yield surfaces on the σ–T plane and radial straight lines, are used. This results in the derivation of the equation of the θ = θ ( $$\bar {\sigma }$$ , k) form. To verify the adequacy of this relationship, the experimental part of the investigation is fulfilled. Powder billets preliminarily compacted at a pressure of 1000 MPa and temperature 325°C are subjected to electroerosion cutting along the axial section to form planar samples (templates). Several characteristic segments are selected on the template surface to determine the local surface porosity by quantitative metallography. The stress state was additionally determined in representative segments by the numerical simulation. Values of bulk plastic strain ( $$\varepsilon _{{v}}^{{{\text{pl}}}}$$ ), intensities of tangential stresses (T), and hydrostatic normal stress (σ) are calculated in axial section zones corresponding to the regions under study. It is shown that the stress state coefficient insignificantly affects the porosity upon its variation in a rather broad range (k = –10 to –0.86).

Sensitivity of important parameters in a three‐dimensional simulation of the milling process of sugar cane with modified Drucker–Prager Cap model based on evolutionary material properties

The properties of the milled mixture of sugar cane change greatly during the milling process. The evolution of its properties was modeled using three-dimensional simulation method of the modified Drucker–Prager Cap model. Parameters for the model were determined by dynamic compression tests and simulated contrast test and employed to analyze the changes of roll load, roll torque, the maximum speed of sugar juice, stress, pore pressure, and the maximum void ratio under compression ratios of 1.5–3.5, blanket thicknesses of 40–140 mm, roll diameters of 700–1000 mm, and roll surface speeds of 0.1–0.5 m/s. The following results have been found: compression ratio plays the leading role in stress, pore pressure, roll load, and roll torque which increase with it; blanket thickness is of primary importance for maximum void ratio which increases with it; and roll surface speed has the most obvious effect on maximum sugar juice speed which increases with it. The method of this paper might provide a more accurate prediction for the optimization of these important parameters during the milling process of sugar cane. Practical applications The properties of the milled mixture of sugar cane change greatly during the milling process. However, the material properties for the constitutive model adopted by the researchers were the mean values of those measured. As a result, the predicted results obtained by the model based on the average values of these parameters are different from those obtained by the actual tests. We evolved the law of variation of parameters and adopted a three-dimensional simulation method of the modified Drucker–Prager Cap model to the milling process of sugar cane. Our results show compression ratio is most important for stress, pore pressure, roll load, and roll torque which increase with it; blanket thickness and roll surface speed are of primary importance for maximum void ratio and the most obvious effect on maximum sugar juice speed which increases with them. Information presented here can serve as a guidance for a more accurate prediction for the optimization of these important parameters during the milling process of sugar cane.

Numerical Simulation of Seismic Soil-Pile Interaction in Liquefying Ground

In this paper, the pile-soil interaction of the pile foundation of an inclined straight alternating group in a liquefiable site under a seismic load was studied through the form changes to the pile cap within the inclined straight alternating group. Based on an analysis of the soil acceleration, hole pressure ratio, horizontal displacement of the pile body, vertical displacement of the pile body, and bending moment of the pile body, the dynamic characteristics of the pile soil at the free site are studied with two layers of liquefiable soil. The results show that the sand layer can amplify seismic waves under a seismic load, and therefore, the soil acceleration under the pile foundation model of the high-rise pile cap group is slightly greater than that of the low-rise pile cap model; then, the pore pressure ratios at the monitoring point in the low-rise pile cap and high-rise pile cap pile foundation models present certain fluctuations. The analysis of the pile displacement and the bending moment shows that the pile foundation from the high-rise pile cap group can resist the seismic load better than that from the low-rise pile cap group.

Abstract 390: Prostate cancer progression depends on the activity of the mitotic kinase citron kinase

Abstract Androgen receptor (AR) is the major driver of prostate cancer (CaP) progression. Despite initially inducing remissions, androgen deprivation therapy (ADT) does not cure CaP and the majority of CaP that recurs under ADT continues to rely on AR. In a subset of patients, administration of novel, more potent ADT drugs leads to emergence of a neuroendocrine (NE) CaP phenotype that is AR-indifferent and even harder to treat. The molecular mechanisms by which AR regulates cell cycle progression and that can be developed into alternative targets to inhibit CaP growth, overcome acquired resistance to ADT, or prevent NE progression, however, remain largely unknown. Here, we identify citron kinase (CIT), which controls cell division, as a novel drugabble target that acts downstream of AR. In multiple CaP models, CIT protein expression was stimulated selectively by low doses of androgens that promote CaP cell proliferation and decreased by AR silencing or short-term administration of AR-antagonist enzalutamide, confirming its AR dependence. Silencing of CIT significantly reduced CaP cell viability and cell proliferation, delayed cell progression, increased the number of multinucleated cells in ADT-naïve and -recurrent CaP cells, and attenuated CaP growth in xenograft models. Overexpression of CIT, transiently or stably, stimulated CaP cell proliferation in androgen-supplemented conditions and under ADT, and this depended entirely on an intact CIT kinase domain. In 2 independent clinical CaP datasets, CIT mRNA levels increased during CaP progression and higher CIT expression correlated with shorter disease-free and overall survival. Using CaP tissue microarrays that contain more than 200 patient specimens, CIT protein expression was significantly higher in primary CaP when compared to adjacent non-neoplastic prostate tissues and correlated with increasing Gleason scores, validating the relevance of CIT overexpression to CaP aggressiveness. Integrated RNA-Seq, MSigDB and GSEA analyses confirmed that the AR- and CIT-dependent transcriptome preferentially controlled CaP cell cycle progression and proliferation. Mechanistically, the use of inhibitors of gene transcription, mRNA translation and proteasome indicated that the androgen-dependence of CIT expression is regulated at the post-transcriptional level. Specifically, CIT protein expression was controlled by the E2F family of cell cycle regulators, with androgen-responsive E2F2 as the major determinant of CaP CIT expression. Our work, thus, isolated a novel role for the mitotic kinase CIT in AR-dependent CaP cell proliferation and clinical progression and identified CIT’s kinase moiety as a novel target for CaP therapy. Funding: NIH/NCI, Case Comprehensive Cancer Center Pilot Research Award Citation Format: Salma Ben-Salem, Salam Bachour, Varadha Balaji Venkadakrishnan, Yixue Su, Eduardo Cortes Gomez, Qiang Hu, Eric Klein, Nicolas Marlo, Cristina Magi-Galluzzi, Liu Song, Hannelore V. Heemers. Prostate cancer progression depends on the activity of the mitotic kinase citron kinase [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 390.

Concrete constitutive models for low velocity impact simulations

Concrete structures are commonly exposed to low velocity impact loads originating from windborne/waterborne debris, vehicle/vessel collision, and rock fall. For the performance assessment of concrete structures under such loads, several constitutive models have been developed to date. To compare the accuracy of the available models for practical applications, the current study evaluates four constitutive models, i.e., continuous surface cap model (CSCM), elasto-plastic damage cap (EPDC) model, Karagozian and Case concrete (KCC) model, and Winfrith concrete model. For this purpose, the constitutive models are first examined at the material level through single element simulations under basic stress paths, such as uniaxial compression and tension, as well as triaxial compression. A range of measures, such as post-peak softening, shear dilation, and confinement effect, are extracted and compared. The investigation is then extended to understand how the concrete constitutive models perform at the structure level. This is achieved by replicating drop hammer tests on reinforced concrete (RC) and concrete filled steel tube (CFST) beams. Investigation of these two structural categories provides a unique opportunity to further evaluate the accuracy of the concrete constitutive models in interaction with the most common reinforcement details. To achieve this goal, the impact responses of RC and CFST beams are compared with full-scale experimental test data. Upon understanding the capabilities of each constitutive model in predicting the structural behavior and damage, the most important modeling parameters are examined. The outcome of this study facilitates the selection and use of concrete constitutive models for the design and assessment of concrete structures subjected to various low velocity impact loads.

Lithium-containing surface pre-reacted glass fillers enhance hDPSC functions and induce reparative dentin formation in a rat pulp capping model through activation of Wnt/β-catenin signaling

Surface pre-reacted glass (S-PRG) fillers are new bioactive molecules used in dental clinic work to fill tooth defects. These fillers release various types of ions (Al+3, BO−3, Na+, SiO3−2, Sr+2 and F−) and exhibit high biocompatibility, antibacterial capability, reduced plaque accumulation, and enhanced osteoblast differentiation. We previously showed that cement of S-PRG fillers could induce tertiary dentin formation in rat models. Previous work also showed that lithium ions can activate the Wnt/β-catenin signaling pathway in vitro and induce dentin formation in pulpotomized teeth in vivo. In the current study, we sought to enhance the effect of S-PRG cement by incorporating LiCl. We show that treatment of human dental pulp stem cells with eluates from S-PRG/LiCl combination cements leads to an upregulation in cell migration, differentiation, and mineralization in vitro. In pulp-capping animal trials, we found that S-PRG/LiCl cements could induce tertiary dentin formation 28-days post-capping. At 7 days post-capping, we identified both β-catenin and Axin2 expression using immunofluorescence, indicative of Wnt/β-catenin signaling activity. In conclusion, S-PRG/LiCl cement is highly effective in promoting human dental pulp stem cells profiles and in enhancing reparative dentin formation in rat teeth through activation of the Wnt/β-catenin canonical signaling pathway. Statement of SignificanceThis is the first study to assess the behavior of S-PRG fillers containing lithium ions on human dental pulp stem cells. We show that this new combination cement promotes positive cell responses by activating the endogenous Wnt/β-catenin signaling pathway in the pulp. The Wnt/β-catenin canonical signaling pathway is involved in many developmental and wound healing processes. The released lithium ions from the S-PRG cement were systematically detected <0.01 mmol/L in our rat model. But it was efficient to induce tertiary dentin formation at the defect site. Since this novel bioactive cement is potentially a promising material for clinical pulp regenerative therapy, future human clinical trials will be needed.

Prediction of tablet characteristics based on sparse modeling for residual stresses simulated by the finite element method incorporating Drucker-Prager cap model

Effects of residual stresses on the mechanical characteristics of tablets such as tensile strength (TS) and disintegration time (DT) were investigated. The residual stresses were simulated using the finite element method (FEM), in which the powder compaction was represented by a Drucker-Prager cap (DPC) model under unconstrained condition. As model tablet formulations, we employed powder mixtures comprising various quantities of lactose (LAC), corn starch (CS), and microcrystalline cellulose (MCC). Key parameters of DPC model were well predicted as a function of quantity ratio of LAC, CS, and MCC. A clear difference was observed in the residual stress distributions between the flat and convex tablets. Strong stresses remained in the convex tablets, while they were rather weak in the flat tablets. For a sparse modeling, an elastic-net (ENET) regression was employed to identify specific stress sites in the tablets. Consequently, the ENET regression revealed specific significant sites in the tablet affecting the TS and DT values. Both quantity and direction of the remaining stresses acting at specific sites close to the die wall were crucial in the convex tablets to predict the TS and DT values; however, no such tendency was seen in the flat tablet.

Volumetric estimate of bordered pits in Pinus sylvestris based on X-ray tomography and light microscopy imaging

Bordered pits are a major determinant for the hydraulic function of wood tissues. Unlike microscopic imaging (e.g. light and electron microscopy) that is constrained to two-dimensional (2D) information, X-ray micro-computed tomography (XμCT) contributes to three-dimensional (3D) analysis. This advantage was used to estimate the volume of bordered pits in Pinus sylvestris. The 3D data obtained by XμCT were compared with two mathematical models (ellipsoid model and spherical cap model) using 2D data obtained by transmission light microscopy and XμCT. The findings of this study showed that the volume approximation using the ellipsoid model revealed values close to the volumes, which were three-dimensionally obtained by XμCT. This trend, however, is more pronounced for pits in earlywood than in latewood. Nevertheless, this study demonstrated that microscopic images can also be used for the approximation of pit volumes to some extent. Researchers should be aware of limitations that come with the 3D method (e.g. resolution, image analysis) and 2D method (unknown location of the section in the pit) as well as the natural variation of the pit morphology.

Investigation on the dynamic liquefaction responses of saturated granular soils due to dynamic compaction in coastal area

Dynamic compaction (DC) has been widely used for a variety of soil types and conditions in coastal area. However, as the ground water table is near the ground surface, a significant increase of pore water pressure is noticed after each impact, which results in local liquefaction and limits further drop effect. Consequently, to obtain effective compaction effects on saturated soils, it is essential for the evaluation of the liquefaction responses of soil medium caused by DC to determine the time delay between the drops and prevent ‘rubbery soil’. In this study, a numerical investigation on the liquefaction responses of saturated granular soils during DC is carried out using a coupled hydro-mechanical model. The developed model considers all the stages of DC involved in impact stage and consolidation stage. A new cap model for simulations of high strain rate behaviors of soils under DC is incorporated in the coupled hydro-mechanical model. Verification of the proposed model is performed against the previous test data and analytical result. Then, a series of parametric studies have been performed to examine the effects of the tamping energy level, hammer radius and permeability on liquefaction responses of saturated granular soils at several stages of DC. The numerical results demonstrate that the dimension of liquefaction zone is driven by the tamping energy level rather than the permeability, and strain rate has a significant effect on soil responses in DC.

Study on elastoplastic coupling mechanics model of the milled mixture of sugar cane

Abstract At present, the phenomenon of elastoplastic coupling isn’t considered in establishing the mechanics model of the milled mixture of sugar cane. In order to describe elastoplastic coupling and yield characteristics, based on uniaxial confined compression tests and direct shear tests, the evolution of the elastic parameters of the solid fiber with void ratio and the plastic deformation, and the plastic mechanics behavior of the solid fiber is described by Modified Drucker-Prager Cap model, the expressions of the parameters of the plastic mechanics model are derived and the corresponding parameters are calculated; and the elastoplastic coupling mechanics model is established. The evolution of the parameters of the model is achieved by the custom subroutine written in Fortran, the numerical simulation of the elastoplastic coupling model is realized by ABAQUS. The results of uniaxial confined compression tests and finite element simulation show that the elastoplastic coupling mechanics model is more accurate than the non-elastoplastic coupling mechanics model to predict the axial pressure. The results provide an important reference for the analysis and understanding of the milling process of sugar cane and the establishment of an accurate mathematical model of the milled mixture of sugar cane.

Finite element analysis of briquetting of iron ore fines

Briquetting is a continuous compaction process to transform loose powders into solid briquettes. The density and strength of formed briquettes vary significantly in the process, affecting the quality of products. This work presented a numerical modelling of briquetting based on Finite Element Method (FEM), focusing on the evolutions of briquette structure and stress. The mechanical behaviour of powders was characterised by the density independent Drucker-Prager Cap (DPC) model. The parameters in the DPC model were determined by conducting experimental die compaction on iron ore fines. The stress distributions inside the briquettes at the maximum compression and ejection stages were analysed. The relative density, Von Mises stress and hydrostatic pressure showed clear declines from the top to the bottom. The effects of powder-wall friction and feeding pressure on briquetting were studied. The average relative density and power draw increased almost linearly with increasing feeding pressure. However, a nonlinear trend was observed with increasing friction. The results suggested that an optimal briquetting process could be achieved by selecting proper boundary conditions.

Coupled Modeling of Sedimentary Basin and Geomechanics: A Modified Drucker–Prager Cap Model to Describe Rock Compaction in Tectonic Context

The aim of basin modeling is to characterise fluids and rocks in a basin considering its history and data partly describing its present state. In usual basin simulators, only a simplified description of geomechanics based on the hypothesis of oedometric strain is used. To both enhance the modeling of basin history and to characterise actual in situ stresses, the effect of stress redistribution, horizontal stresses, and strain variations during basin history should be considered. To address this point, a coupled basin-geomechanics framework based on a new constitutive law is proposed in this paper using the prototype simulator $$\mathrm{A}^{2}$$ . This framework has been built to provide relevant results for various kinds of basin cases including tectonic loading. A finite strain poromechanical approach is considered along with an modified Drucker–Prager Cap model to describe rock compaction under natural sedimentation, erosion, and tectonics. The constitutive model can be seen as a tensorial extension of the compaction models of Athy or Schneider as it allows to recover the same behaviour in oedometric context. Simple test cases are modeled considering typical sand or shale properties, emphasizing the effect of tectonic loading on the present-day pore pressures and in situ stresses. It appears that even relatively moderate tectonic loading ( $$5\%$$ of horizontal strain) can lead to overpressures of several hundreds of bars and to a complete change in in situ stress regime for deeply buried layers (above a depth of 2000 m).

Effect of tissue inhibitor of metalloprotease 1 on human pulp cells invitro and rat pulp tissue invivo.

To evaluate the dentinogenetic effects of tissue inhibitor of metalloprotease (TIMP1) on human pulp cells invitro and rat pulp tissue invivo. The effect of TIMP1 on pulp cell functions related to hard tissue formation as part of the wound healing process (i.e. biocompatibility, proliferation, differentiation and mineralized nodule formation) was evaluated invitro and using a direct pulp capping experimental animal model invivo. The effects of different-sized cavity preparations on hard tissue formation induced by ProRoot MTA at 2weeks were evaluated using micro-computed tomography (micro-CT). Tertiary dentine formation quality and quantity after pulp capping using TIMP1, ProRoot MTA and phosphate-buffered saline (PBS) was also evaluated after 4weeks using micro-CT in term of dentine volume (DV), dentine mineral density (DVD) and histological analysis. The data were evaluated by Student's t-test, one-way ANOVA with Tukey's post hoc test, the Kruskal-Wallis test or the Steel-Dwass test. P values<0.05 were considered statistically significant. TIMP1 significantly stimulated dental pulp stem cell proliferation, differentiation, and mineralization and was more biocompatible compared with the PBS control (P<0.05). In the pulp capping model, the amount of tertiary dentine that formed was directly proportional to the size of the pulp exposure; greater amounts of tertiary dentine were observed in pulps with larger exposures after 2 weeks. 4-week samples of TIMP1 and ProRoot MTA had similar characteristics, but both sample significantly induced tertiary dentine formation beneath the cavity compared with PBS (P < 0.05) under standardized cavity preparations. TIMP1 has an important role in pulpal wound healing, which makes it a potential biological pulp capping material and candidate molecule for regenerative endodontic therapy.