Этиопатогенетические аспекты терапии хронических воспалительных заболеваний органов малого таза

Наведено сучасні принципи лікування запальних захворювань жіночих статевих органів з урахуванням етіопатогенезу запалення й особливостей продукції у цервікальному слизу запальних і протизапальних цитокинів. Показано, що включення до комплексу терапії інтерферонів сприяє відновленню порушеного імунологічного гомеостазу й зниженню ймовірності рецидивів захворювання.Modern principles of treatment of inflammatory diseases of female genitals taking into account an etiopathogenesis of an inflammation and features of production in сervical mucous inflammatory and antiinflammatory cytokines are resulted. Including in a complex of therapy of interferons is shown, that, promotes restoration of the broken immunologic homeostasis and depression of probability of relapses of disease

Cathodoluminescence as a tracing technique for quartz precipitation in low velocity shear experiments

Two simulated gouges (a pure quartz and a quartz-muscovite mixture) were experimentally deformed in a ring shear apparatus at a constant low velocity under hydrothermal conditions favourable for dissolution–precipitation processes. Microstructural analysis using scanning electron microscope cathodoluminescence imaging and cathodoluminescence spectroscopy combined with chemical analysis showed that quartz dissolution and precipitation occurred in both experiments. The starting materials and deformation conditions were chosen so that dissolution–precipitation microstructures could be unambiguously identified from their cathodoluminescence signal. Precipitated quartz was observed as blue luminescent fracture fills and overgrowths with increased Al content relative to the original quartz. In the pure quartz gouge, most of the shear deformation was localized on a boundary-parallel slip surface. Sealing of fractures in a pulverized zone directly adjacent to the slip surface may have helped keeping the deformation localized. In the quartz-muscovite mixture, some evidence was observed of shear-accommodating precipitation of quartz in strain shadows, but predominantly in fractures, elongating the original grains. Precipitation of quartz in fractures implies that the length scale of diffusive mass transfer in frictional-viscous flow is shorter than the length of the quartz domains. Additionally, fracturing might play a more important role than generally assumed. Our results show that cathodoluminescence, especially combined with chemical analysis, is a powerful tool in microstructural analyses of experimentally deformed quartz-bearing material and visualizing quartz precipitation

Investigation of strain localization in sheared granular layers using 3-D discrete element modeling

In this work, we investigate slip localization in sheared granular faults at seismic velocities using 3-D numerical simulations with the discrete element method (DEM). An aggregate of non-destructive spherical particles is subjected to direct shear by using two moving boundaries in a sandwich configuration to identify the impact of particle-scale parameters on slip localization. We impose a thin layer of fine-grained particles with variable contrast in thickness and grain size adjacent to the boundary as well as in the middle of the granular layer to simulate boundary and Y shears observed in both natural and laboratory fault gouges. The results show that larger amounts of strain is accommodated within the pre-described finer-grained layer even with a small (< 10%) contrast in grain size. Up to 90% of the displacement is localized in a finer-grained layer when the contrast ratio of the grain size is 50%. Based on the concept of the average spreading velocity of particles and squeeze expulsion theory in granular flow, we suggest that the phenomenon of localization is likely from result from the contribution of larger grains collisions with smaller grains. Since the amount of frictional heat generated depends on the degree of localization, the results provide crucial information on the heat generation and associated slip accommodation in sheared gouge zones. We conclude that the occurrence of a weaker, fine-grained layer within a dense fault zone is likely to result in self-enhanced weakening of the fault planes

Fault Weakening During Short Seismic Slip Pulse Experiments: The Role of Pressurized Water and Implications for Induced Earthquakes in the Groningen Gas Field

High-velocity friction experiments on simulated fault gouges sheared at high normal stress and to low displacement are particularly relevant to induced seismicity, which is becoming an important topic in fault mechanics. Using a new, improved set-up, which allows simulation of fault stress and fluid pressure ((Formula presented.)) conditions approaching in-situ reservoir values, we performed ring-shear experiments on simulated fault gouges prepared from the source-, reservoir-, and caprock-formations of the Groningen gas field. Pre-sheared gouges were subjected to a rotational slip pulse reaching ∼1.0 m/s peak velocity and 13–16 cm total displacement at effective normal stresses ((Formula presented.)) of 5–31 MPa and (Formula presented.) up to 5 MPa, using water or dry nitrogen as pore fluid. All water-saturated gouges show strong dynamic weakening within a few cm of slip, with the lowest dynamic friction (0.2–0.4) measured at the highest (Formula presented.). By contrast, the weakening was subtle in experiments using nitrogen. Our analyses focus on the high- (Formula presented.) experiments, which are more realistic and show a distinct dependence of constitutive parameters (e.g., slip-weakening rate) on (Formula presented.), in the form of empirical linear, power-law or exponential relations. The results provide much-needed constraints for numerical modeling of induced rupture propagation in the Groningen field. Based on temperature- and (Formula presented.) -measurements made in near-direct contact with the active shear band, and using “post-mortem” microstructures, we exclude previously-proposed dynamic weakening mechanisms (e.g., flash heating or thermal pressurization) and suggest that water pressurization at heated asperity or grain contacts explains the weakening seen in our high- (Formula presented.) experiments

The frictional strength and stability of spatially heterogeneous fault gouges

Along-fault lithological heterogeneity is observed in all fault zones that cross-cut compositional layering. Numerical modelling studies on fault rupture nucleation, propagation and arrest often assume that the fault mechanical behaviour is governed by either the rheologically weak phase or by a homogeneous gouge mixture of juxtaposing lithologies. However, the effects of spatial heterogeneity on fault gouge composition and hence its frictional behaviour are less known. In this study, we simulate a mixture of mechanically contrasting rheologies of claystones and sandstones in fault gouges by using lithologies available in the well-known Groningen gas field stratigraphy (Ten Boer and Slochteren members, respectively). Friction experiments were performed in a rotary shear configuration to accommodate the large displacements required to study mixing and clay smearing in faults with large offsets. A velocity stepping procedure was conducted to quantify the rate-dependence of friction and its evolution with displacement. A spatial heterogeneity was introduced by segmentation of the simulated gouge in claystone and sandstone patches. In contrast to previous studies, we show that Slochteren sandstone gouges can exhibit velocity-weakening behaviour related to strain-localization in a principal slip zone with reduced grain size. Our experiments on segmented gouges show displacement-dependent changes in the sliding friction and its rate-dependence. Clay smearing and shear localization on foliation planes cause weakening of the gouge and a shift from velocity-weakening to velocity-strengthening behaviour. Progressive shearing leads to juxtaposition of sandstone segments that are separated only by a thin clay smear. We propose that the associated increase in friction is caused by lithology mixing at the interfaces between the clay smear and the bulk Slochteren sandstone gouge, and by the disruption of continuous Y-shears. Progressive shearing does not lead to a decrease in the rate-sensitivity parameter (a-b). This observation suggests that shearing remains localized on phyllosilicate foliations, possibly accommodated by the increased width of the principal slip zone (PSZ) with displacement. Our results show that fault friction and its rate-dependence are not simply governed by the weakest lithology along a fault plane, nor that they can be simply represented by a homogeneous mixture of the juxtaposing lithologies. Detailed knowledge of the stratigraphic layering in combination with the fault offset is required to predict the macroscopic frictional behaviour of heterogeneous fault gouges

Hydrothermal Friction Experiments on Simulated Basaltic Fault Gouge and Implications for Megathrust Earthquakes

Nucleation of earthquake slip at the plate boundary fault (décollement) in subduction zones has been widely linked to the frictional properties of subducting sedimentary facies. However, recent seismological and geological observations suggest that the décollement develops in the subducting oceanic crust in the depth range of the seismogenic zone, at least in some cases. To understand the frictional properties of oceanic crustal material and their influence on seismogenesis, we performed hydrothermal friction experiments on simulated fault gouges of altered basalt, at temperatures of 100–550°C. The friction coefficient (μ) lies around 0.6 at most temperature conditions but a low μ down to 0.3 was observed at the highest temperature and lowest velocity condition. The velocity dependence of μ, (a−b), changes with increasing temperature from positive to negative at ∼100°C and from negative to positive at ∼450°C. Compared to gouges derived from sedimentary facies, the altered basalt gouge showed potentially unstable velocity weakening over a wider temperature range. Microstructural observations and microphysical interpretation infer that competition between dilatant granular flow and viscous compaction through pressure-solution creep of albite contributed to the observed transition in (a−b). Alteration of oceanic crust during subduction produces fine grains of albite and chlorite through interactions with interstitial water, leading to reduction in its frictional strength and an increase in its seismogenic potential. Therefore, shear deformation possibly localizes within the altered oceanic crust leading to a larger potential for the nucleation of a megathrust earthquake in the depth range of the seismogenic zone

Lower crustal earthquakes in the East African Rift System: Insights from frictional properties of rock samples from the Malawi rift

Earthquakes in the southern part of the East African Rift System (EARS) occur at depths up to 45 km in the lower crust, unusually deep for an extensional regime. Typically, earthquakes in continental crust nucleate at temperatures 400 °C. These results are consistent with earthquake nucleation in mafic material, if present, at lower crustal P-T conditions. On the other hand, the data indicate that earthquake nucleation is unlikely in felsic material at temperatures above 500 °C, unless effective normal stress is low and strain rate is elevated by several orders of magnitude

Observational and theoretical evidence for frictional-viscous flow at shallow crustal levels

Along the Hikurangi Subduction Margin, accretionary prism uplift has exposed the Hungaroa fault zone, an inactive thrust developed within the Middle to Late Eocene Wanstead Formation. Within the ~33 m-wide fault core, deformation of the smectitic, calcareous mudstone matrix produced a penetrative foliation that locally wraps around clasts. Deformation occurred at temperatures constrained by syntectonic calcite vein clumped isotope thermometry, which yielded a narrow range of Δ47 values between 0.445 ± 0.024‰ and 0.482 ± 0.013‰, corresponding to a mean calcite precipitation temperature of 82−12+13 °C. Optical and scanning electron microscopy analyses reveal that calcite underwent: dissolution along stylolites and clast, vein, and microlithon margins; precipitation in foliation-parallel and foliation-perpendicular extension veins; and precipitation in hybrid veins and strain fringes. Maximum differential stress estimates obtained from calcite twin densities (44.1 ± 13.9 to 96.6 ± 20.8 MPa) are consistent with those sustainable by a cohesionless fault at ~3 km depth with a friction coefficient in the range measured for two calcareous mudstones (μ = 0.38 to 0.50) and a micrite clast (μ = 0.61 and 0.64). Marlstone clasts within the foliated calcareous mudstone matrix contain mutually cross-cutting shear fractures and extension veins with crack-seal textures, providing evidence for temporal fluctuations in shear strength resulting from pore fluid overpressure transients. At strain rates imposed during laboratory experiments, frictional sliding involves granular flow processes. Yet, calcite microstructures indicate that diffusive mass transfer played an important role in accommodating deformation. We model the fault zone rheology assuming diffusion-controlled frictional-viscous flow, with deformation at strain rates γ˙≤ 10−9 s−1 able to have taken place at very low shear stresses (τ < 10 MPa) given sufficiently short diffusion distances (d < 0.1 mm), even in the absence of pore fluid overpressures. However, if grain-scale and fracture-scale processes change the diffusion distance, fault zones deforming via frictional-viscous flow can exhibit temporally variable strain rates. Thus, our results suggest that the shallow (up-dip) limit of the seismogenic zone is not a simple function of temperature in fault zones governed by a frictional-viscous flow rheology

A combined linkage, microarray and exome analysis suggests MAP3K11 as a candidate gene for left ventricular hypertrophy

Background: Electrocardiographic measures of left ventricular hypertrophy (LVH) are used as predictors of cardiovascular risk. We combined linkage and association analyses to discover novel rare genetic variants involved in three such measures and two principal components derived from them. Methods: The study was conducted among participants from the Erasmus Rucphen Family Study (ERF), a Dutch family-based sample from the southwestern Netherlands. Variance components linkage analyses were performed using Merlin. Regions of interest (LOD > 1.9) were fine-mapped using microarray and exome sequence data. Results: We observed one significant LOD score for the second principal component on chromosome 15 (LOD score = 3.01) and 12 suggestive LOD scores. Several loci contained variants identified in GWAS for these traits; however, these did not explain the linkage peaks, nor did other common variants. Exome sequence data identified two associated variants after multiple testing corrections were applied. Conclusions: We did not find common SNPs explaining these linkage signals. Exome sequencing uncovered a relatively rare variant in MAPK3K11 on chromosome 11 (MAF = 0.01) that helped account for the suggestive linkage peak observed for the first principal component. Conditional analysis revealed a drop in LOD from 2.01 to 0.88 for MAP3K11, suggesting that this variant may partially explain the linkage signal at this chromosomal location. MAP3K11 is related to the JNK pathway and is a pro-apoptotic kinase that plays an important role in the induction of cardiomyocyte apoptosis in various pathologies, including LVH