1,921 research outputs found
Geopolymers: A new and smart way for a sustainable development
âGeopolymersâ is a general term that describes a wide variety of inorganic and composite materials with limited restrictions on alumina and silica content. In the last decades, they have been also defined as âlow-temperature aluminosilicate glassesâ, âhydroceramicsâ, âinorganic polymer concreteâ or âalkali bonded ceramicsâ. Recently, an updated definition has been proposed by the RILEM Technical Committee 224-AAM: âgeopolymer materials are essential aluminosilicates activated with alkaline solution, excluding any other alkali-activated materials that should be classified apartâ [1]
Simulation of the 2009, Mw = 4 Tehran earthquake using a hybrid method of modal summation and finite difference
The Greater Tehran Area is the most important city of Iran and hosts about 20% of the country?s population. Despite the presence of major faults and the occurrence of historical earthquakes, the seismicity is relatively low at present. Thus, it is important to estimate the ground motion for preventive, reliable seismic hazard assessment. An earthquake with magnitude Mw = 4, which occurred close to Tehran, 17 October 2009, is the first local earthquake that has been recorded by the local strong ground motion network in Tehran. To simulate the ground motion caused by the earthquake a hybrid technique is used. It combines two methods: the analytical modal summation and the numerical finite difference, taking advantage of the merits of both. The modal summation is applied to simulate wave propagation from the source to the sedimentary basin and finite difference to propagate the incoming wavefield in the laterally heterogeneous part of the structural model that contains the sedimentary basin. Synthetic signals are simulated along two East?West and Southeast?Northwest profiles. Frequency, response spectra, and time domain, waveforms and peak values, parameters are computed synthetically and compared with observed records. Results show agreement between observed and simulated signals. The simulation shows local site amplification as high as 6 in the southern part of Tehran
When membranes need an ESCRT : endosomal sorting and membrane remodelling in health and disease
Originally discovered as regulators of cargo sorting during endosomal trafficking, ESCRT (endosomal sorting complexes required for transport) proteins are emerging as flexible machines that shape the behaviour of membranes throughout the cell. Deregulation of ESCRT activity is observed in neuro-degenerative diseases, virus infection and cancer. However, the mechanisms of pathogenesis involving ESCRTs have not yet fully come into focus. Here, we review the current knowledge of ESCRT function in health and disease and provide educated guesses for future research and focused therapeutic intervention
Toward one world or many? A comparative analysis of OECD and UNESCO global education policy documents
Education policymaking has gone global. The 2030 Agenda for Sustainable Development aims to galvanize efforts to promote sustainable development, decrease global inequalities, and realize universal quality education. Supporting these efforts, two leading international organizations, UNESCO and the OECD, have set out normative frameworks for their vision of global education. This paper examines the policy discourses of these organizations in light of SDG 4âEducation. Specifically, through a comparative analysis of selected terms and underlying concepts in key policy documents, the paper distinguishes between UNESCO's notion of global citizenship and the OECD's framework for global competence. Ultimately, the authors discuss whether the organizations' agendas are aimed at a common global vision, or, alternatively, towards two distinct and divergent conceptualizations of an imagined future
High-pressure behaviour of GeO2: a simulation study
In this work we study the high pressure behaviour of liquid and glassy GeO2
by means of molecular dynamics simulations. The interaction potential, which
includes dipole polarization effects, was parameterized from first-principles
calculations. Our simulations reproduce the most recent experimental data to a
high degree of precision. The proportion of the various GeOn polyhedra is
determined as a function of the pressure: a smooth transition from tetrahedral
to octahedral network is observed. Finally, the study of high-pressure, liquid
germania confirms that this material presents an anomalous behaviour of the
diffusivity as observed in analog systems such as silica and water. The
importance of penta-coordinated germanium ions for such behaviour is stressed.Comment: 16 pages, 4 figures, accepted as a Fast Track Communication on
Journal of Physics: Condensed Matte
Combining molecular and metabolomic analysis to evaluate transgenic Vitis vinifera plants expressing the Vitreoscilla haemoglobin (VHb)
Transgenic V. vinifera 'Brachetto' plants expressing Vitreoscilla stercoraria haemoglobin gene (vhb) were obtained by transferring the pBI-VHb construct harbouring the vhb and the nptII genes, via A. tumefaciens EAH 105. From 18 distinct transgenic plantlets, 2 lines were randomly chosen and 11 and 14 plants respectively obtained by micropropagation were acclimated for 100 days in the greenhouse, together with 10 micropropagated plants of a wild-type control line. A data-driven assessment, aimed at evaluating all measurable lowmolecular weight organic compounds in these transgenic plants was performed using UPLC-Q-TOF with an ESI interface. Comparisons between controls and transgenic lines and between the two transgenic lines detected significant differences in some metabolic patterns. For each line, a list of identified compounds was extracted from the 100 most significant biomarkers
Effect of antithrombotic therapy on postoperative outcome of 538 consecutive emergency laparoscopic cholecystectomies for acute cholecystitis. Two Italian centerâs study
The risk of developing hemorrhagic complications during or after emergency cholecystectomy (EC) for acute cholecystitis (AC) in patients with antithrombotic therapy (ATT) remains uncertain. In this double-center study, we evaluated post-operative outcomes in patients with ATT undergoing EC. We retrospectively evaluated 538 patients who underwent laparoscopic EC for AC between May 2015 and December 2019 at two referral centers. 89 of them (17%) were on ATT. We defined postoperative complication rates, including bleeding, as our primary outcome. Mortality was higher in the ATT group. Morbidity was higher in the ATT group as well; however, the difference was not statistically significant. 12 patients (2%) experienced intraoperative blood loss over 500 ml and ten (2%) had postoperative bleeding complications. Two patients (< 1%) experienced both intraoperative and postoperative bleeding. On multivariate analysis, ATT was not significantly associated with worse postoperative outcomes. Antithrombotic therapy is not an independently associated factor of severe postoperative complications (including bleeding) or mortality. However, these patients still represent a challenging group and must be carefully managed to avoid postoperative bleeding complications
Recurrent Microinvasive Subungueal Squamous Cell Carcinoma in a HIV Patient: a Case of Good Response to Photodynamic Therapy.
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Modulating the WNT pathway in Drosophila models of Cornelia de Lange Syndrome
Cornelia de Lange syndrome (CdLS) is a rare genetic disorder affecting neurodevelopment and the gastrointestinal and musculoskeletal systems. CdLS is caused by mutations within NIPBL, SMC1A, SMC3, RAD21, HDAC8 and BRD4 genes. These genes codify for the cohesin complex (or associated proteins), a multiprotein structure playing a role in chromatid adhesion, DNA repair and gene expression regulation. Our laboratory has shown that a strong correlation exists between cohesin complex function and WNT signalling, an intracellular pathway involved in regulation of expression of several genes controlling cell division and embryonic development. Recently, it has been observed that in nipblb- and smc1a-loss-of-function zebrafish embryos, in NIPBL- and SMC1A- mutated patient fibroblasts and in CdLS murine neural stem cells (NSCs) similar patterns of canonical WNT pathway alterations and cyclinD1 downregulation are present. Indeed, zebrafish embryos adverse phenotype was rescued by chemical activation of the WNT pathway. Drosophila melanogaster is an inexpensive model to study CdLS and to screen in vivo for therapeutic compounds. Therefore, we have used flies\u2019 strains mutated in nipped-B and hdac3 genes (respectively NIPBL and HDAC8 in humans) for assessing the existing correlation between cohesin complex and WNT pathway. Moreover, we have selected D. melanogaster mutants to screen for chemicals that revert the CdLS associated-phenotypes efficiently. In particular, we have tested WNT activators in order to investigate which effects they have on the mutated flies, assessing body weight and changes in brain structures (i.e. mushroom bodies) and possibly select compounds to test on vertebrate models. Funding: This work has been supported by Fondazione Cariplo, grant 2015-0783 to Valentina Massa
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