Evaluation of dynamic explicit mpm formulations for unsaturated soils

Many applications in geohazards prevention involve large deformations of unsaturated soils, e.g. rainfall induced landslides, embankment collapses due to wetting etc. These phenomena can be investigated with multiphase implementations of the Material Point Method (MPM) able to account for the behaviour of unsaturated soils. This paper compares two formulations: (i) afully coupled three-phase formulation(3P)in which the governing equations are derived from the momentum balance and the mass balance equations of solid, liquid and gas phase assuming non-zero gas pressure,the primary unknowns are the absolute accelerationsof the phases (aS–aL–aG formulation); (ii)a simplified approachthatneglectsthe momentum balance equation of the gas(2P_s).Potentialities and limitations of these approaches are highlighted consideringa 1D infiltration problem.Despite the introduced simplifications, the simplified formulation gives reasonably good results in many engineering cases

Role of Estrogen and Estrogen Receptor in GH-Secreting Adenomas

Acromegaly is a rare disease with several systemic complications that may lead to increased overall morbidity and mortality. Despite several available treatments, ranging from transsphenoidal resection of GH-producing adenomas to different medical therapies, complete hormonal control is not achieved in some cases. Some decades ago, estrogens were first used to treat acromegaly, resulting in a significant decrease in IGF1 levels. However, due to the consequent side effects of the high dose utilized, this treatment was later abandoned. The evidence that estrogens are able to blunt GH activity also derives from the evidence that women with GH deficiency taking oral estro-progestins pills need higher doses of GH replacement therapy. In recent years, the role of estrogens and Selective Estrogens Receptor Modulators (SERMs) in acromegaly treatment has been re-evaluated, especially considering poor control of the disease under first- and second-line medical treatment. In this review, we analyze the state of the art concerning the impact of estrogen and SERMs on the GH/IGF1 axis, focusing on molecular pathways and the possible implications for acromegaly treatment

Comparison of global gridded precipitation products over a mountainous region of Africa

Five gridded monthly precipitation products are evaluated using a gauge network over complex topography in Africa. The global gridded products considered are produced by the Global Precipitation Climatology Center (GPCC), NOAA Climate Prediction Center (NOAA-CPC), and the Climate Research Unit at the University of East Anglia (UEA-CRU). Three different products from GPCC are available at multiple spatial resolutions: 0.5, 1 and 2.5° ; the NOAA-CPC product has a spatial resolution of 2.5° while that of UEA-CRU is 0.5° . Comparisons of the GPCC and UEA-CRU products are carried out at spatial resolutions of 0.5, 1 and 2.5° , while NOAA-CPC is compared with the other products only at 2.5° resolution. There is very strong agreement between the gridded global products and the reference raingauge data. Average correlation coefficients are about 0.95, 0.92, and 0.90 at 2.5, 1.0 and 0.5° spatial resolutions, respectively. Both systematic and random errors are reasonably low. The performance of these products is highest during the wettest season (Jun-Aug), and relatively poor during the dry season (Dec-Feb). The seasonal differences are more prominent at high resolution. These results are very encouraging, particularly, when considering the complex terrain of the validation site

Myrmekite and strain weakening in granitoid mylonites

At mid-crustal conditions, deformation of feldspar is mainly accommodated by a combination of fracturing, dissolution\u2013precipitation, and reaction-weakening mechanisms. In particular, K-feldspar is reaction-weakened by the formation of strain-induced myrmekite \u2013 a \ufb01ne-grained symplectite of plagioclase and quartz. Here we use electron backscattered diffraction to (i) investigate the microstructure of a granodiorite mylonite, developed at 3c 450 \ub0C during cooling of the Rieserferner pluton (Eastern Alps); and (ii) assess the microstructural processes and the weakening associated with myrmekite development. Our analysis shows that the crystallographic orientation of plagioclase in pristine myrmekite was controlled by that of the replaced K- feldspar. Myrmekite nucleation resulted in both grain-size reduction and anti-clustered phase mixing by heterogeneous nucleation of quartz and plagioclase. The \ufb01ne grain size of sheared myrmekite promoted grain-size-sensitive creep mechanisms including \ufb02uid-assisted grain boundary sliding in plagioclase, coupled with heterogeneous nucleation of quartz within creep cavitation pores. Flow laws, calculated for monomineralic quartz, feldspar, and quartz + plagioclase aggregates (sheared myrmekite) during deformation at 450 \ub0C, show that grain-size-sensitive creep in sheared myrmekite accommodated strain rates several orders of magnitude higher than monomineralic quartz layers deforming by dislocation creep. Therefore, diffusion creep and grain size-sensitive processes contributed signi\ufb01cantly to bulk rock weakening during mylonitization. Our results have implications for modelling the rheology of the felsic middle crust

Romanian ancient gold objects provenance studies using micro-beam methods: the case of "Pietroasa" hoard

Abstract Five fragments of ancient gold objects belonging to Pietroasa "Closca cu Puii de Aur" ("The Golden Brood Hen with Its Chickens") Romanian hoard were analysed using the micro-PIXE (particle induced X-ray emission) technique. The purpose of the study was to gain some more knowledge regarding the metal provenance by determining the presence of PGE (Platinum Group Elements) and other high-temperature melting point trace elements (Ta, Nb, Cr) at a micrometric scale. Ta and Nb inclusions (micrometric areas of composition different from the surroundings) on three samples and Pd inclusions on one sample were found. The measurements led to some conclusions for the possible gold ore sources of Pietroasa treasury: the South-Ural Mountains, Nubia (Sudan) and/or Anatolian deposits and Roman imperial coins

Complications and mortality of Cushing’s disease: report on data collected over a 20-year period at a referral centre

Context: Cushing’s disease (CD) is rare condition burdened by several systemic complications correlated to higher mortality rates. The primary goal of clinicians is to achieve remission, but it is unclear if treatment can also increase life expectancy. Aim: To assess the prevalence of cortisol-related complications and mortality in a large cohort of CD patients attending a single referral centre. Materials and methods: The clinical charts of CD patients attending a referral hospital between 2001 and 2021 were reviewed. Results: 126 CD patients (median age at diagnosis 39 years) were included. At the last examination, 78/126 (61.9%) of the patients were in remission regardless of previous treatment strategies. Patients in remission showed a significant improvement in all the cardiovascular (CV) comorbidities (p < 0.05). The CV events were more frequent in older patients (p = 0.003), smokers and persistent CD groups (p < 0.05). Most of the thromboembolic (TE) and infective events occurred during active stages of the disease. The CV events were the most frequent cause of death. The standardized mortality ratio (SMR) resulted increased in persistent cases at the last follow-up (SMR 4.99, 95%CI [2.15; 9.83], p < 0.001) whilst it was not higher in those in remission (SMR 1.66, 95%CI [0.34; 4.85], p = 0.543) regardless of the timing or number of treatments carried out. A younger age at diagnosis (p = 0.005), a microadenoma (p = 0.002), and remission status at the last follow-up (p = 0.027) all increased survival. Furthermore, an elevated number of comorbidities, in particular arterial hypertension, increased mortality rates. Conclusions: Patients with active CD presented a poor survival outcome. Remission restored the patients’ life expectancy regardless of the timing or the types of treatments used to achieve it. Persistent CD-related comorbidities remained major risk factors

Corticotropin-releasing hormone test predicts the outcome of unilateral adrenalectomy in primary bilateral macronodular adrenal hyperplasia

Purpose: Primary bilateral adrenal hyperplasia (PBMAH) is associated with hypercortisolism and a heterogeneous clinical expression in terms of cortisol secretion and related comorbidities. Historically, treatment of choice was bilateral adrenalectomy (B-Adx); however, recent data suggest that unilateral adrenalectomy (U-Adx) may be an effective alternative. For the latter, factors predicting the postsurgical outcome (e.g., biochemical control) have not been identified yet. Methods: PBMAH patients undergoing U-Adx for overt Cushing's syndrome (CS) in two tertiary care centers were retrospectively analysed. Remission was defined as a normalization of urinary free cortisol (UFC) without the need for medical treatment. The potential of hCRH test as a predictor of U-Adx outcome was evaluated in a subgroup. Results: 23 patients were evaluated (69% females, mean age 55 years). Remission rate after U-Adx was 74% at last follow up (median 115 months from UAdx). Before U-Adx, a positive ACTH response to hCRH (Δ¬TH increase > 50% from baseline) was associated with higher remission rates. Conclusions: Three of four patients with PBMAH are surgically cured with U-Adx. Pre-operative hCRH testing can be useful to predict long-term remission rates

Simulating water and soil gushing around shield tunnel with Material Point Method

In recent years, serious accidents due to sand and water gushing around shield tunnel happen from time to time. Sand and water gushing could lead to large soil displacement, change soil stress field around tunnels, and then threaten the safety of tunnel structures. To date, there is a lack of theoretical research on the evolution of sand and water gushing, and the numerical simulation of the process is challenging because soil-water interaction, soil-structure interaction and large deformations have to be accounted for. In this paper, the Material Point Method (MPM) is used to deal with large deformation and various simulation cases considering different gushing locations at tunnels are carried out to investigate the development of soil displacement and stress around tunnels due to water and soil gushing. The results show that position of the gushing point greatly affect the damage scope. The sand gushing rate, the soil displacement and stress field, the ground settlement trough, and the earth pressure on the tunnel linings develop completely differently due to the varying position of the gushing point, which are analyzed to suggest reasonable guidance and countermeasures for preventing future sand and water gushing accidents