Complex structural and functional changes occur in the arterial system with advancing age. The aged artery is characterized by changes in microRNA expression patterns, autophagy, smooth muscle cell ...migration and proliferation, and arterial calcification with progressively increased mechanical vessel rigidity and stiffness. With age the vascular smooth muscle cells modify their phenotype from contractile to ‘synthetic’ determining the development of intimal thickening as early as the second decade of life as an adaptive response to forces acting on the arterial wall. The increased permeability observed in intimal thickening could represent the substrate on which low‐level atherosclerotic stimuli can promote the development of advanced atherosclerotic lesions. In elderly patients the atherosclerotic plaques tend to be larger with increased vascular stenosis. In these plaques there is a progressive accumulation of both lipids and collagen and a decrease of inflammation. Similarly the plaques from elderly patients show more calcification as compared with those from younger patients. The coronary artery calcium score is a well‐established marker of adverse cardiovascular outcomes. The presence of diffuse calcification in a severely stenotic segment probably induces changes in mechanical properties and shear stress of the arterial wall favouring the rupture of a vulnerable lesion in a less stenotic adjacent segment. Oxidative stress and inflammation appear to be the two primary pathological mechanisms of ageing‐related endothelial dysfunction even in the absence of clinical disease. Arterial ageing is no longer considered an inexorable process. Only a better understanding of the link between ageing and vascular dysfunction can lead to significant advances in both preventative and therapeutic treatments with the aim that in the future vascular ageing may be halted or even reversed.
Content List – Read more articles from the symposium: Nobel Conference: Cell Cycle and Cell Death in Disease.
Obesity is rising worldwide at an alarming rate and so is the incidence of obesity‐related disorders, such as the metabolic syndrome, type 2 diabetes and cardiovascular diseases. The ...obesity‐dependent vascular damage appears to be derived from a variety of changes in the adipose tissue, leading to a chronic inflammatory state and dysregulation of adipocyte‐derived factors. This, in turn, impairs vascular homeostasis by determining an unbalance between the protective effect of the nitric oxide pathway and the unfavourable action of the endothelin‐1 system. In addition, hyperinsulinemia and insulin resistance contribute to vascular dysfunction because the opposing endothelium‐dependent vasodilating and vasoconstrictor effects of insulin are shifted towards a predominant vasoconstriction in patients with obesity. Importantly, emerging evidence suggests that the vascular dysfunction of obesity is not only limited to the endothelium but also involves the other layers of the vessel wall. In particular, obesity‐related changes in vascular smooth muscle seem to disrupt the physiological facilitatory action of insulin on the responsiveness to vasodilator stimuli, whereas the adventitia and the perivascular fat appear to be a source of proinflammatory and vasoactive factors that may contribute to endothelial and smooth muscle cell dysfunction and to the pathogenesis of vascular disease.
We present a new tomographic model for P- and S-velocity anomalies beneath Europe (30°N–55°N, 5°W–40°E), extending in depth up to 700 km and constrained by inversion of data from the International ...Seismological Center (ISC) catalogue. The algorithm uses the traveltimes from events located in the study area recorded by all available worldwide stations, as well as times from teleseismic events recorded by European stations. The events from the ISC catalogue have been relocated and combined into composite events. All the traveltimes were corrected for crustal structure using the reference model EuCRUST-07. The resulting velocity anomalies show similar large-scale patterns as observed in previous studies, but have a higher resolution, which allows detection of some features in more detail. For example, it is now possible to assess the depth extension of the small slow velocity body beneath the Eifel region and Eger graben. The P and the S model show a good consistency in the uppermost 200 km below most of the European area and in some parts even in the deeper layers (e.g. beneath the Apennines and the Hellenic arc). The new model provides clear images of some principal features, which were previously detected in a limited number of studies, while the comparison between P- and S-velocity anomalies provides novel constraints to address on their nature (e.g. the gap in the Adriatic plate subducted below the central-southern Apennines). In this paper, we pay special attention to testing the reliability of the results. The random noise effect is evaluated using a test with independent inversion of two data subsets (with odd/even events). The spatial resolution is estimated using different checkerboard tests. Furthermore, we present a synthetic model with realistic patterns, which reproduces after performing forward and inverse modelling the same shape and amplitudes of the anomalies as in the case of the real data inversion. In this case, the parameters of the model can be used to assess the amplitudes of P and S anomalies that is critical for evaluation of other petrophysical parameters (temperature, density, composition, etc.) in the upper mantle.
Recently, the continually increasing availability of seismic data has allowed high‐resolution imaging of lithospheric structure beneath the African cratons. In this study, S‐wave seismic tomography ...is combined with high resolution satellite gravity data in an integrated approach to investigate the structure of the cratonic lithosphere of Africa. A new model for the Moho depth and data on the crustal density structure is employed along with global dynamic models to calculate residual topography and mantle gravity residuals. Corrections for thermal effects of an initially juvenile mantle are estimated based on S‐wave tomography and mineral physics. Joint inversion of the residuals yields necessary compositional adjustments that allow to recalculate the thermal effects. After several iterations, we obtain a consistent model of upper mantle temperature, thermal and compositional density variations, and Mg# as a measure of depletion, as well as an improved crustal density model. Our results show that thick and cold depleted lithosphere underlies West African, northern to central eastern Congo, and Zimbabwe Cratons. However, for most of these regions, the areal extent of their depleted lithosphere differs from the respective exposed Archean shields. Meanwhile, the lithosphere of Uganda, Tanzania, most of eastern and southern Congo, and the Kaapvaal Craton is thinner, warmer, and shows little or no depletion. Furthermore, the results allow to infer that the lithosphere of the exposed Archean shields of Congo and West African cratons was depleted before the single blocks were merged into their respective cratons.
Plain Language Summary
Cratons are the ancient cores of continents that, with few exceptions, are underlain by a cold, strong lithospheric root with a thickness of about 250 km. The physical properties of lithospheric roots, principally temperature and composition, shed light on the origin and evolution of the most ancient portions of the Earth's lithosphere, the Precambrian cratons. We use an iterative method to process S‐wave seismic tomography and satellite gravity data to calculate the thermal and compositional state of the lithosphere. Our results reveal great diversity in the thickness and physical properties of the African lithosphere. The West African, northern Congo, and Zimbabwe cratons are underlain by relatively cold, thick and chemically depleted lithosphere. In contrast, the Uganda, Tanzania, southern Congo, and Kaapvaal cratons are warmer, thinner and have a less depleted (or non‐depleted) composition, indicating either refertilization (metasomatism) or formation in a non‐depleted state. These results document the formation of the Africa continent during the past 3.7 Ga from a diverse collection of cratons, each with a unique evolutionary history.
Key Points
A new Moho map was constructed from available seismic data to improve thermo‐compositional modeling of the African cratonic lithosphere
Lithosphere of the West African, central to northern Congo, and Zimbabwe cratons is cold, up to 250 km thick, and chemically depleted
Hot, thin (<200 km) and mostly undepleted lithosphere of Uganda, Tanzania, southern Congo, and Kaapvaal cratons indicates refertilization
In this study, we describe the mode of extension of the Vavilov, a fossil backarc basin, triangle-shaped (approximately 240km-wide and 200km-long), located between Sardinia margin to the west and ...Campania margin to the east. We combine the analysis of recent geophysical and geological data, in order to investigate the relationship between the crustal/sedimentary structure and the tectonic evolution of both apex and bathyal parts of the basin. With this aim, we interpret a large data set of multichannel seismic reflection profiles and several well logs. We observe that the apex basin corresponds to a sediment-balanced basin, with a sedimentary infill recording the episodes of basin evolution. In contrast, the distal basin corresponds to an underfilled basin, characterized by localized volcanic activity and a thin sedimentary succession that covers the exhumed mantle. The basin architecture reveals the occurrence of rift and supradetachment basins in the Vavilov rift zone. We find that the rifting of the Vavilov triangular basin was synchronous from the apex to distal regions around a single Euler pole located in Latium, between 5.1 and 1.8Ma. The kinematic evolution of the Vavilov basin occurred in two stages: initial pure shear mode (5.1–4.0Ma) that produced high-angle normal faults and syn-sedimentary wedges, followed by simple shear mode (4.0–1.8Ma) that caused supradetachment basins filled by a Transgressive-Regressive succession that documents high subsidence rates (1.22mm/y) in the apex region. The final stage of extension in the distal region led to: (i) complete embrittlement of the crust; (ii) direct continuation of crustal faults to upper mantle depth; (iii) serpentinization and mantle exhumation. Based on constraints on the present-day crustal structure of the Vavilov basin, we obtain a stretching value (β=3.5) and extension rates (3cm/y) in the bathyal zone analogous to those reported for magma-poor rifted margins.
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•We combine the analysis of geological data and a recent seismic tomography model•We describe the mode of extension of a triangular backarc basin•Initial pure shear stage was followed by simple shear stage until mantle exhumation
We propose a synchronous rifting of the basin from the apex to distal regions
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•Local Green's functions to estimate hydrological loading displacements.•Consideration of heterogeneities in Earth's crust.•Scatter plots show dependency between loading response and ...local crustal structure.•Crustal stratification influences near-field displacements.•Impact of crustal structure is relevant for hydrological loading displacements.
The influence of the elastic Earth properties on seasonal or shorter periodic surface deformations due to atmospheric surface pressure and terrestrial water storage variations is usually modeled by applying a local half-space model or an one dimensional spherical Earth model like PREM from which a unique set of elastic load Love numbers, or alternatively, elastic Green's functions are derived. The first model is valid only if load and observer almost coincide, the second model considers only the response of an average Earth structure. However, for surface loads with horizontal scales less than 2500km2, as for instance, for strong localized hydrological signals associated with heavy precipitation events and river floods, the Earth elastic response becomes very sensitive to inhomogeneities in the Earth crustal structure.
We derive a set of local Green's functions defined globally on a 1°×1° grid for the 3-layer crustal structure TEA12. Local Green's functions show standard deviations of ±12% in the vertical and ±21% in the horizontal directions for distances in the range from 0.1° to 0.5°. By means of Green's function scatter plots, we analyze the dependence of the load response to various crustal rocks and layer thicknesses. The application of local Green's functions instead of a mean global Green's function introduces a variability of 0.5–1.0mm into the hydrological loading displacements, both in vertical and in horizontal directions. Maximum changes due to the local crustal structures are from −25% to +26% in the vertical and −91% to +55% in the horizontal displacements. In addition, the horizontal displacement can change its direction significantly. The lateral deviations in surface deformation due to local crustal elastic properties are found to be much larger than the differences between various commonly used one-dimensional Earth models.
Hyperpolarization causing smooth muscle relaxation contributes to the maintenance of vascular homeostasis, particularly in small‐calibre arteries and arterioles. It may also become a compensatory ...vasodilator mechanism upregulated in states with impaired nitric oxide (NO) availability. Bioassay of vascular hyperpolarization in the human circulation has been hampered by the complexity of mechanisms involved and the limited availability of investigational tools. Firm evidence, however, supports the notion that hyperpolarization participates in the regulation of resting vasodilator tone and vascular reactivity in healthy subjects. In addition, an enhanced endothelium‐derived hyperpolarization contributes to both resting and agonist‐stimulated vasodilation in a variety of cardiovascular risk conditions and disease. Thus, hyperpolarization mediated by epoxyeicosatrienoic acids (EETs) and H2O2 has been observed in coronary arterioles of patients with coronary artery disease. Similarly, ouabain‐sensitive and EETs‐mediated hyperpolarization has been observed to compensate for NO deficiency in patients with essential hypertension. Moreover, in non‐hypertensive patients with multiple cardiovascular risk factors and in hypercholesterolaemia, KCa channel‐mediated vasodilation appears to be activated. A novel paradigm establishes that perivascular adipose tissue (PVAT) is an additional regulator of vascular tone/function and endothelium is not the only agent in vascular hyperpolarization. Indeed, some PVAT‐derived relaxing substances, such as adiponectin and angiotensin 1‐7, may exert anticontractile and vasodilator actions by the opening of KCa channels in smooth muscle cells. Conversely, PVAT‐derived factors impair coronary vasodilation via differential inhibition of some K+ channels. In view of adipose tissue abnormalities occurring in human obesity, changes in PVAT‐dependent hyperpolarization may be relevant for vascular dysfunction also in this condition.
In the present study we analyzed the influence of density heterogeneity in the sedimentary cover on estimates of the effective elastic thickness (EET) of the lithosphere based on a cross‐spectral ...analysis of gravity and topography data. The fan wavelet coherence technique was employed to calculate EET for most of Europe and adjoining southern mountain belts. We employed Bouguer gravity anomalies and topography corrected for the effect of density variations within sediments. Correcting for sediments considerably suppresses the effect of unexpressed subsurface loads and substantially reduces EET estimates in areas with negligible topography variations as it was demonstrated for North Europe and East European Platform. The results show a good correspondence between the EET patterns and tectonic fragmentation of Europe and better agree with independent estimates based on the strength model of the lithosphere. Therefore, considering of the effect of sediments is essential for correct determinations of EET in flat areas.
Plain Language Summary
The lithosphere is the outer rigid shell of the Earth, which overlies a viscous layer, called the asthenosphere. Knowledge of the lithosphere strength is important, for example, for understanding earthquake activity. Effective elastic thickness is a proxy for lithospheric strength and corresponds to the thickness of a homogeneous elastic plate, which deforms under loading in the same way as the real lithosphere. Thus, far, different methods used to determine this parameter have given controversial results. We demonstrate that considering the effect of sediments, which represent the soft uppermost crustal layer, provides a possibility for obtaining more consistent results. New effective elastic thickness estimates show that the European lithosphere is divided into two parts along the Trans European Suture Zone. Western Europe is characterized by predominantly low values of the effective elastic thickness and consequently weak lithosphere. In contrast, the lithosphere in Eastern Europe is much stronger. Regional variations of the effective elastic thickness obtained in this study are consistent with the tectonic partitioning of Europe with the surrounding mountain belts and help to understand ongoing tectonic processes.
Key Points
Considering the effect of sediments significantly reduces estimates of the lithospheric effective elastic thickness in flat areas
Correcting for sediments suppresses the effect of unexpressed subsurface loads and substantially reduces calculation uncertainties
The results show a good correspondence between the effective elastic thickness variations and tectonic fragmentation of Europe
Many studies consider the contamination of dental unit waterlines (DUWLs), but few of them have studied the possible presence of antibiotic resistant Pseudomonas aeruginosa in the DUWLs.
...Investigation of the presence of P. aeruginosa and Pseudomonas spp. strains in DUWLs and evaluation of their resistance to six antibiotics (ceftazidime, netilmicin, piperacillin/tazobactam, meropenem, levofloxacin, colistin sulfate) at a public dental clinic in Milan, Italy.
Dental units were contaminated by P. aeruginosa with loads of 2-1,000 CFU/L and were mainly located on the mezzanine floor, with a range of 46-54%, while Pseudomonas spp. were primarily found on the first and second floors, ranging from 50 to 91%. P. aeruginosa was antibiotic resistant in 30% of the strains tested, andPseudomonas spp. in 31.8% . Cold water from controls was also contaminated by these microorganisms.
Monitoring antibiotic resistance in the water and adopting disinfection procedures on DUs are suggested within the Water Safety Plan.
We create a 3‐D density, temperature, and composition model of the Antarctic lithosphere using an integrative approach combining gravity, topography, and tomography data with mineral physics ...constraints and seismic data on crustal structures. The latter is used to create a new Moho and crustal density model. Temperature and thermal density variations are estimated based on S wave velocities from two independent tomography models (SL2013sv and AN1‐S). Results of the Antarctic continent show the well‐known distinction between East and West Antarctica in temperature and density to a depth of about 200 km. Incorporating compositional variations in the temperature calculations increases temperatures in depleted regions by up to 150 °C, giving improved insights into thermal structures. The thickness of the lithospheric root also varies strongly between these regions, with values below 100 km in the west and above 200 km in the east. Regions with negative compositional density variations (<−0.040 g/cm3 at 100 km), high depletion (Mg # > 91.5), and low temperatures (<800 °C; central Dronning Maud Land, along the east flank of the Transantarctic Mountains) are interpreted as Precambrian cratonic fragments. Nearly undepleted lithosphere is found in the Lambert Graben and the Aurora Subglacial Basin and is attributed to Mesozoic rifting activity that has caused lithospheric rejuvenation.
Plain Language Summary
Antarctica remains one of the least studied areas on Earth, because large ice masses and climate conditions strongly hinder measurements. It plays an important role in global phenomena such as sea level change. In order to understand and predict these processes, we need knowledge about the heat coming from the Earth's interior. It has been recently recognized that the thermal state of the lithosphere, the rigid outer shell of the Earth, plays an important role in controlling dynamics of the ice shield and, thus, global sea level changes. Therefore, we create a model of the lithosphere describing the variation in temperature, density, and composition. Before, such models were created by using some single data set (usually seismic tomography). We employ a new integrative approach, combining several data sets to create a comprehensive 3‐D model of the Antarctic lithosphere. Combination of various data sets gives more robust models than when using a single approach. Our results of the Antarctic continent show strong differences between East and West Antarctica in temperature and density to a depth of about 200 km. Regions with negative compositional density variations and low temperatures are identified within East Antarctica and are interpreted as being substantially older than the surrounding continent.
Key Points
Inversion of gravity, topography and seismic tomography data yields improved thermal, density and compositional models of the upper mantle
Precambrian cratonic fragments were identified in Eastern Antarctica
Almost undepleted lithosphere is found in the Lambert Graben and the Aurora Subglacial Basin
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