Polyhedral units and network connectivity in calcium aluminosilicate glasses from high-energy x-ray diffraction

Structure factors for Cax/2AlxSi1-xO2 glasses (x=0,0.25,0.5,0.67) extended to a wave vector of magnitude Q= 40 1/A have been obtained by high-energy x-ray diffraction. For the first time, it is possible to resolve the contributions of Si-O, Al-O and Ca-O coordination polyhedra to the experimental atomic pair distribution functions (PDF). It has been found that both Si and Al are four-fold coordinated and so participate in a continuous tetrahedral network at low values of x. The number of network breaking defects in the form of non-bridging oxygens (NBO's) increases slowly with x until x=0.5 (NBO's ~ 10% at x=0.5). By x=0.67 the network breaking defects become significant as evidenced by the significant drop in the average coordination number of Si. By contrast, Al-O tetrahedra remain free of NBO's and fully integrated in the Al/Si-O network for all values of x. Calcium maintains a rather uniform coordination sphere of approximately 5 oxygen atoms for all values of x. The results suggest that not only Si/Al-O tetrahedra but Ca-O polyhedra, too, play a role in determining the glassy structure

LEARNING FROM THE PAST TO FACE THE FUTURE: LANDSLIDES IN THE PIAVE VALLEY (EASTERN ALPS, ITALY)

Landslides are a critical process in landscape evolution and may pose a serious threat to people and infrastructure. In the last decades, a growing interest in such phenomena has developed in the Alps, where narrow valleys are increasingly in\uachabited, and landslides have caused several casualties. Understanding the driving factors, triggers, evolution, and impact of past and future failures is of the utmost importance when dealing with land use and risk reduction. In this paper, four distinct case stud\uacies are presented, showing how different approaches can interact and produce a comprehensive understanding of a landslide event. All examples lie in the middle sector of the Piave Valley (NE Italy) and deal with failures that occurred in the distant past (i.e., the historic Masiere di Vedana rock avalanche), in the near past (i.e., the 1963 Vajont event), in the present (i.e., the 60-years -lasting Tessina landslide) and in the future (i.e., possible Mt. Peron instabilities). The final goal of the paper is to show how the understanding of past landslides is fundamental to obtain reliable predictions on future failures, and how modelling designed to predict the evolution of potential detachments can be applied to understand the dynamics of ancient events

Functional Characterization of a CRH Missense Mutation Identified in an ADNFLE Family

Nocturnal frontal lobe epilepsy has been historically considered a channelopathy caused by mutations in subunits of the neuronal nicotinic acetylcholine receptor or in a recently reported potassium channel. However, these mutations account for only a minority of patients, and the existence of at least a new locus for the disease has been demonstrated. In 2005, we detected two nucleotide variations in the promoter of the CRH gene coding for the corticotropin releasing hormone in 7 patients. These variations cosegregated with the disease and were demonstrated to alter the cellular levels of this hormone. Here, we report the identification in an Italian affected family of a novel missense mutation (hpreproCRH p.Pro30Arg) located in the region of the CRH coding for the protein pro-sequence. The mutation was detected in heterozygosity in the two affected individuals. In vitro assays demonstrated that this mutation results in reduced levels of protein secretion in the short time thus suggesting that mutated people could present an altered capability to respond immediately to stress agents

The i148m Pnpla3 polymorphism influences serum adiponectin in patients with fatty liver and healthy controls

BACKGROUND: Reduced adiponectin is implicated in the pathogenesis of nonalcoholic fatty liver disease (NAFLD) and steatohepatitis (NASH), and the I148M Patatin-like phospholipase domain-containing 3 (PNPLA3) polymorphism predisposes to NAFLD and liver damage progression in NASH and chronic hepatitis C (CHC) by still undefined mechanisms, possibly involving regulation of adipose tissue function. Aim of this study was to evaluate whether the I148M PNPLA3 polymorphism influences serum adiponectin in liver diseases and healthy controls. METHODS: To this end, we considered 144 consecutive Italian patients with NAFLD, 261 with CHC, 35 severely obese subjects, and 257 healthy controls with very low probability of steatosis, all with complete clinical and genetic characterization, including adiponectin (ADIPOQ) genotype. PNPLA3 rs738409 (I148M) and ADIPOQ genotypes were evaluated by Taqman assays, serum adiponectin by ELISA. Adiponectin mRNA levels were evaluated by quantitative real-time PCR in the visceral adipose tissue (VAT) of 35 obese subjects undergoing bariatric surgery. RESULTS: Adiponectin levels were independently associated with the risk of NAFLD and with the histological severity of the disease. Adiponectin levels decreased with the number of 148\u2009M PNPLA3 alleles at risk of NASH both in patients with NAFLD (p\u2009=\u20090.03), and in healthy subjects (p\u2009=\u20090.04). At multivariate analysis, PNPLA3 148\u2009M alleles were associated with low adiponectin levels (<6\u2009mg/ml, median value) independently of NAFLD diagnosis, age, gender, BMI, and ADIPOQ genotype (OR 1.67, 95% c.i. 1.07-2.1 for each 148\u2009M allele). The p.148\u2009M PNPLA3 variant was associated with decreased adiponectin mRNA levels in the VAT of obese patients (p\u2009<\u20090.05) even in the absence of NASH. In contrast, in CHC, characterized by adiponectin resistance, low adiponectin was associated with male gender and steatosis, but not with PNPLA3 and ADIPOQ genotypes and viral features. CONCLUSIONS: The I148M PNPLA3 variant is associated with adiponectin levels in patients with NAFLD and in healthy subjects, but in the presence of adiponectin resistance not in CHC patients. The I148M PNPLA3 genotype may represent a genetic determinant of serum adiponectin levels. Modulation of serum adiponectin might be involved in mediating the susceptibility to steatosis, NASH, and hepatocellular carcinoma in carriers of the 148\u2009M PNPLA3 variant without CHC, with potential therapeutic implications

Towards a map of the Upper Pleistocene loess of the Po Plain Loess Basin (Northern Italy)

Upper Pleistocene (MIS 4-2) loess sequences occur in most of continental Europe and in Northern Italy along the Po Plain Loess Basin. Loess is distributed along the flanks of the Po Plain and was deposited on glacial deposits, fluvial terraces, uplifted isolated hills, karst plateaus, slopes and basins of secondary valleys. Loess bodies are generally tiny and affected by pedogenesis, being locally slightly reworked by slope processes and bioturbation. Notwithstanding, loess in the Po Plain is an important archive of paleoenviron-mental record and its mapping provides new insights in paleoenvironmental and palaeoseismic reconstructions of Northern Italy

Plasma 24S-hydroxycholesterol levels in elderly subjects with late onset Alzheimer's disease or vascular dementia: a case-control study

<p>Abstract</p> <p>Background</p> <p>In central nervous system cholesterol cannot be degraded but is secreted into circulation predominantly in the form of its polar metabolite 24(<it>S</it>)-hydroxycholesterol (24S-OH-Chol). Some studies suggested an association between 24S-OH-Chol metabolism and different neurological diseases including dementia. A possible decrease in 24S-OH-Chol plasma levels has been reported late onset Alzheimer's disease (LOAD) and vascular dementia (VD), but results of previous studies are partially contradictory.</p> <p>Methods</p> <p>By high-speed liquid chromatography/tandem mass spectrometry we evaluated the plasma levels of 24S-OH-Chol in a sample of 160 older individuals: 60 patients with LOAD, 35 patients with VD, 25 subjects affected by cognitive impairment no-dementia (CIND), and 40 (144 for genetics study) cognitively normal Controls. We also investigated the possible association between PPARgamma Pro12Ala polymorphism and dementia or 24S-OH-Chol levels.</p> <p>Results</p> <p>Compared with Controls, plasma 24S-OH-Chol levels were higher in LOAD and lower in VD; a slight not-significant increase in CIND was observed (ANOVA p: 0.001). A positive correlation between 24S-OH-Chol/TC ratio and plasma C reactive protein (CRP) levels was found in the whole sample, independent of possible confounders (multiple regression p: 0.04; r²: 0.10). This correlation was strong in LOAD (r: 0.39), still present in CIND (r: 0.20), but was absent in VD patients (r: 0.08). The PPARgamma Pro12Ala polymorphism was not associated with the diagnosis of LOAD, VD, or CIND; no correlation emerged between the Ala allele and 24S-OH-Chol plasma levels.</p> <p>Conclusions</p> <p>Our results suggest that plasma 24S-OH-Chol levels might be increased in the first stages of LOAD, and this phenomenon might be related with systemic inflammation. The finding of lower 24S-OH-Chol concentrations in VD might be related with a more advanced stage of VD compared with LOAD in our sample, and/or to different pathogenetic mechanisms and evolution of these two forms of dementia.</p

The Eastern Lower Tagus Valley Fault Zone in central Portugal : active faulting in a low-deformation region within a major river environment

Active faulting in the Lower Tagus Valley, Central Portugal, poses a significant seismic hazard that is not well understood. Although the area has been affected by damaging earthquakes during historical times, only recently has definitive evidence of Quaternary surface faulting been found along the western side of the Tagus River. The location, geometry and kinematics of active faults along the eastern side of the Tagus valley have not been previously studied. We present the first results of mapping and paleoseismic analysis of the eastern strand of the Lower Tagus Valley Fault Zone (LTVFZ). Geomorphological, paleoseismological, and seismic reflection studies indicate that the Eastern LTVFZ is a left-lateral strike-slip fault. The detailed mapping of geomorphic features and studies in two paleoseismic trenches show that surface fault rupture has occurred at least six times during the past 10 ka. The river offsets indicate a minimum slip rate on the order of 0.14–0.24 mm/yr for the fault zone. Fault trace mapping, geomorphic analysis, and paleoseismic studies suggest a maximum magnitude for the Eastern LTVFZ of Mw ~ 7.3 with a recurrence interval for surface ruptures ~ 1.7 ka. At least two events occurred after 1175 ± 95 cal yr BP. Single-event displacements are unlikely to be resolved in the paleoseismic trenches, thus our observations most probably represent the minimum number of events identified in the trenches