634 research outputs found

    Bioerosion by microbial euendoliths in benthic foraminifera from heavy metal-polluted coastal environments of Portovesme (South-Western Sardinia, Italy)

    Get PDF
    A monitoring survey of the coastal area facing the industrial area of Portoscuso-Portovesme (south-western Sardinia, Italy) revealed intense bioerosional processes. Benthic foraminifera collected at the same depth (about 2 m)but at different distances from the pollution source show extensive microbial infestation, anomalous Mg/Ca molar ratios and high levels of heavy metals in the shell associated with a decrease in foraminifera richness, population density and biodiversity with the presence of morphologically abnormal specimens. We found that carbonate dissolution induced by euendoliths is selective, depending on the Mg content and morpho-structural types of foraminiferal taxa. This study provides evidences for a connection between heavy metal dispersion, decrease in pH of the sea-water and bioerosional processes on foraminifera

    Automated generation of flat tileable patterns and 3D reduced model simulation

    Get PDF
    The computational fabrication community is developing an increasing interest in the use of patterned surfaces, which can be designed to show ornamental and unconventional aesthetics or to perform as a proper structural material with a wide range of features. Geometrically designing and controlling the deformation capabilities of these patterns in response to external stimuli is a complex task due to the large number of variables involved. This paper introduces a method for generating sets of tileable and exchangeable flat patterns as well as a model-reduction strategy that enables their mechanical simulation at interactive rates. This method is included in a design pipeline that aims to turn any general flat surface into a pattern tessellation, which is able to deform under a given loading scenario. To validate our approach, we apply it to different contexts, including real-scale 3D printed specimens, for which we compare our results with the ones provided by a ground-truth solver

    Fossichnus solus and Oichnus simplex, two peculiar ichnospecies in modern benthic foraminifera from a polluted area in SW coast of Sardinia, Italy

    Get PDF
    The modern benthic foraminiferal tests collected from a coastal area of south-western Sardinia (Portoscuso-Portovesme) that is heavily polluted by industrial activity reveal intense and widespread bioerosional structures induced by diversifi ed microborers. A large number of the foraminifera reveals microscopic round holes (1-60 μm in diameter) and roundish concavities (25x40 μm in external diameter) on their surface that belong, respectively, to the ichnospecies Oichnus simplex Bromley, 1981, and Fossichnus solus Nielsen et al., 2003. These traces just occur in the tests of the foraminifera which are heavily infested by microendolithic cyanobacteria, algae and fungi suggests comparable ethological behaviour between the ichnospecies Fossichnus and Oichnus and the microbial euendoliths that are ascribed to individual biological taxa. The greater occurrence of F. solus and O. simplex in the high-Mg foraminiferal porcelanaceous tests than in the low-Mg foraminiferal hyaline tests reveals that the bioerosional processes seem to be related to the Mg/Ca ratio, as well as to morphological structures of the taxa

    Distribution of HLA-DPB1, -DQB1 -DQA1 alleles among Sardinian celiac patients.

    Get PDF
    The Sardinian population in many aspects differs from other Caucasoid populations, particularly for its degree of homogeneity. For this reason we have studied 50 adult Sardinian patients with celiac disease (CD) and 50 control healthy Sardinian individuals by RFLP analysis and by extensive oligotyping for 17 HLA-DPB 1, 8-DQB I and 9-DQA 1 alleles, and established their -DPB I alleles and -DQB I -DQA I genotypes. The heterodimer HLA-DQB 1 *0201/-DQA 1 *0501, present in 96% of our patients, is strongly associated with CD susceptibility, confirming published reports. On the other hand we found in 11 of 50 probands (22%) the presence of the allele -DQB 1 *05021 DQA1*0102. This genotype is extremely rare in other Caucasian populations and appears to confer limited protection in CD Sardinian patients

    Pulmonary transit time as a marker of diastolic dysfunction in Takotsubo syndrome

    Get PDF
    AIM: To evaluate the pulmonary transit time (PTT) and its derived parameters using cardiac magnetic resonance imaging (CMRI) as markers of diastolic dysfunction in Takotsubo syndrome (TS) and its relationship with transthoracic echocardiography and CMRI parameters. MATERIALS AND METHODS: Twenty-two patients with TS, who exhibited diastolic dysfunction as assessed by transthoracic echocardiography, were enrolled retrospectively and the PTT, pulmonary transit time index (PTTI), and pulmonary blood volume index (PBVI) were evaluated using first-pass CMRI. PTT was calculated as the number of cardiac cycles required for a bolus of contrast agent to move from the right ventricle (RV) to the left ventricle (LV), whereas PTTI represents the PTT interval corrected for the heart rate. Finally, PBVI was calculated as the product of PTTI, and RV stroke volume indexed for body surface area. Normal references of PTT, PTTI, and PBVI were evaluated in a cohort of 20 age- and sex-matched healthy controls. RESULTS: Compared with healthy subjects, TS patients showed significantly higher PTT, PTTI, and PBVI (p=0.0001, p=0.0001, and p=0.002, respectively). Using multivariable logistic regression, PBVI provided the best differentiation between TS and controls (AUC 0.84). PBVI was significantly associated with the index of diastolic dysfunction and left atrial strain parameters. In addition, PBVI demonstrated a significant correlation with global T2 mapping (r=0,520, p=0,019). CONCLUSION: PTT and the derived parameters, as assessed using first-pass CMRI, are potential tools for assessing LV diastolic dysfunction in patients with TS

    The INGV-CMCC Seasonal Prediction System: improved ocean initial conditions

    Get PDF
    The development of the INGV (Istituto Nazionale di Geofisica e Vulcanologia)-CMCC (Centro Euro-Mediterraneo per i Cambiamenti Climatici) Seasonal Prediction System (SPS) is documented. In this SPS the ocean initial conditions estimation includes a Reduced Order Optimal Interpolation procedure for the assimilation of temperature and salinity profiles at the global scale. Nine member ensemble forecasts have been produced for the period 1991-2003 for two starting dates per year in order to assess the impact of the subsurface assimilation in the ocean for initialization. Comparing the results with control simulations (i.e.: without assimilation of subsurface profiles during ocean initialization), we showed that the improved ocean initialization increases the skill in the prediction of tropical Pacific SSTs in our system for boreal winter forecasts. Considering the forecast of the El Ni˜no 1997-1998, the data assimilation in the ocean initial conditions leads to a considerable improvement in the representation of its onset and development. Our results indicate a better prediction of global scale surface climate anomalies for the forecasts started in November, probably due to the improvement in the tropical Pacific. For boreal winter, in both tropics and extra tropics, we show significant increases in the capability of the system to discriminate above normal and below normal temperature anomalies

    Low cadmium concentration in whole blood from residents of Northern Sardinia (Italy) with special reference to smoking habits

    Get PDF
    Introduction. The present study was initiated to investigate the cadmium concentrations in whole blood of Northern Sardinian, non-occupationally exposed adult subjects. Sardinia is a large Italian island which differs genetically and environmentally from other mainland Italian areas. Methods. Two hundred and forty-three adults (157 females and 86 males) were selected in the study area from subjects who were undergoing blood collection for laboratory analysis during the period January 2005-May 2005. Whole blood was analysed by graphite furnace atomic absorption spectrometer equipped with a Zeeman-effect background corrector (Perkin Elmer ZL5100) and an auto sampler. The adopted analytical procedure uses the Stabilized Platform Temperature Furnace (STPF) technique. Results. The mean value of Blood Cadmium Concentration (BCdC), expressed as Geometric Mean, was 0.32 mg/l (CI 95%: 0.31-0.34 mg/l) significantly ranging from 0.27 mg/l (CI 95%: 0.26-0.29 mg/l) in non-smokers to 0.34 mg/l (CI 95%: 0.30-0.39 mg/l) in ex-smokers up to 0.47 mg/l (CI 95%: 0.42-0.53 mg/l) in smokers (p inf. 0.0001). Discussion. The results show that BCdC levels in Northern Sar- dinian non-occupationally exposed adults are lower than levels found in many other regions, including those within Italy. Nev- ertheless, similar values have been detected in other European countries and cities. Conclusions. In relation to other reports in which data were analysed by strata for smoking habit and age, we found similar BCdC values among non smokers. However, Sardinian smokers seem to show lower levels of blood cadmium

    A2B Adenosine Receptors and Sphingosine 1-Phosphate Signaling Cross-Talk in Oligodendrogliogenesis

    Get PDF
    Oligodendrocyte-formed myelin sheaths allow fast synaptic transmission in the brain. Impairments in the process of myelination, or demyelinating insults, might cause chronic diseases such as multiple sclerosis (MS). Under physiological conditions, remyelination is an ongoing process throughout adult life consisting in the differentiation of oligodendrocyte progenitor cells (OPCs) into mature oligodendrocytes (OLs). During pathological events, this process fails due to unfavorable environment. Adenosine and sphingosine kinase/sphingosine 1-phosphate signaling axes (SphK/S1P) play important roles in remyelination processes. Remarkably, fingolimod (FTY720), a sphingosine analog recently approved for MS treatment, plays important roles in OPC maturation. We recently demonstrated that the selective stimulation of A(2)(B) adenosine receptors (A(2)(B)Rs) inhibit OPC differentiation in vitro and reduce voltage-dependent outward K(+) currents (I(K)) necessary to OPC maturation, whereas specific SphK1 or SphK2 inhibition exerts the opposite effect. During OPC differentiation A(2)(B)R expression increases, this effect being prevented by SphK1/2 blockade. Furthermore, selective silencing of A(2)(B)R in OPC cultures prompts maturation and, intriguingly, enhances the expression of S1P lyase, the enzyme responsible for irreversible S1P catabolism. Finally, the existence of an interplay between SphK1/S1P pathway and A(2)(B)Rs in OPCs was confirmed since acute stimulation of A(2)(B)Rs activates SphK1 by increasing its phosphorylation. Here the role of A(2)(B)R and SphK/S1P signaling during oligodendrogenesis is reviewed in detail, with the purpose to shed new light on the interaction between A(2)(B)Rs and S1P signaling, as eventual innovative targets for the treatment of demyelinating disorders
    corecore