30,671 research outputs found
The formation of fibrolite nodules in a package of melanocratic gneisses from the Hercynian basement of NE Sardinia, Italy
No full textMarble protection: An inorganic electrokinetic approach
No full textThe influence of an electric potential difference in an aqueous solution was studied as a method for depositing a calcium oxalate coating over a weathered carbonatic stone. Samples of weathered Carrara white marble were treated at 15 and 50 °C for five hours in an electrokinetic cell, specifically conceived for this study, containing a solution of ammonium oxalate (4% by weight), and were subsequently characterised by Scanning Electron Microscopy, X Ray Diffractometry, Thermogravimetric analysis and Mercury Intrusion porosimetry. The electrokinetic treatment proved to be a cost effective and time saving process, able to produce a thick and homogeneous calcium oxalate coating over the stone surface that improves its chemical and physical resistance in low pH environments, and is able to protect the stone from the by-products of urban pollution
The ancient mortars and geomaterials of tower fortification of Nora (Pula, Sardinia, Italy)
No full textThe tower is located on a promontory on the south-western Gulf of Cagliari, near to the Coltellazzo island and the archaeological Punic-Roman of Nora.
The first military settlement was probably present since the beginning of the fourteenth century. Surely the tower was active since 1607. Jorge Aleo (1680) mentions, calling Fortalleza Coltellaz. In the eighteenth century the building was engulfed in a fort, built in a period of six years (1722-1728) by engineer the Piedmont Antonio Felix de Vincenti. Later (in the nineteenth century) further work was carried out until the tower became a lighthouse.
The tower was considered a tower de armas or vigorous, or for heavy defense, with a garrison of men under a commander. Being a watch tower, is in sight of the towers of Cala d'Ostia, San Macario and the Diavolo. The tower has a structure of a truncated cone, with a height of about 11 meters high and 12 meters in diameter at the base. Inside it has a double ribbed vaulted dome, supported by a central pillar. The aim of this research is were studying mortars and geomaterials used of the ashlars, for define: i) composition of ancient mortars with ratio binder/aggregate; ii) provenance of the raw materials used in the mixture of mortars; iii) alteration processes in progress on mortars and on geomaterials used in masonry.
Through the analysis of the physical-mechanical properties, important evidences of chemical and physical decay were highlighted in the mortar of the plasters coating the tower and also in bedding mortars of ashlars of masonry. In some areas, where they are concentrated processes of physical disintegration, also as a result of dissolution of the carbonate matrix of the mortar, show scarce resistance physical-mechanical with consequent detachment from the masonry
The origin of fibrolite-rich nodules in high grade melanocratic gneisses from NE Sardinia,Italy.
No full textHow often parametrial involvement leads to post-operative adjuvant treatment in locally advanced cervical cancer after neoadjuvant chemotherapy and type C radical hysterectomy?
No full textOBJECTIVE
Parametrial involvement (PMI) is one of the most important factors influencing prognosis in locally advanced stage cervical cancer (LACC) patients. We aimed to evaluate PMI rate among LACC patients undergoing neoadjuvant chemotherapy (NACT), thus evaluating the utility of parametrectomy in tailor adjuvant treatments.
METHODS
Retrospective evaluation of consecutive 275 patients affected by LACC (IB2-IIB), undergoing NACT followed by type C/class III radical hysterectomy. Basic descriptive statistics, univariate and multivariate analyses were applied in order to identify factors predicting PMI. Survival outcomes were assessed using Kaplan-Meier and Cox models.
RESULTS
PMI was detected in 37 (13%) patients: it was associated with vaginal involvement, lymph node positivity and both in 10 (4%), 5 (2%) and 12 (4%) patients, respectively; while PMI alone was observed in only 10 (4%) patients. Among this latter group, adjuvant treatment was delivered in 3 (1%) patients on the basis of pure PMI; while the remaining patients had other characteristics driving adjuvant treatment. Considering factors predicting PMI we observed that only suboptimal pathological responses (OR: 1.11; 95% CI: 1.01, 1.22) and vaginal involvement (OR: 1.29 (95%) CI: 1.17, 1.44) were independently associated with PMI. PMI did not correlate with survival (HR: 2.0; 95% CI: 0.82, 4.89); while clinical response to NACT (HR: 3.35; 95% CI: 1.59, 7.04), vaginal involvement (HR: 2.38; 95% CI: 1.12, 5.02) and lymph nodes positivity (HR: 3.47; 95% CI: 1.62, 7.41), independently correlated with worse survival outcomes.
CONCLUSIONS
Our data suggest that PMI had a limited role on the choice to administer adjuvant treatment, thus supporting the potential embrace of less radical surgery in LACC patients undergoing NACT. Further prospective studies are warranted
Deflection and Friction Performance of Waste-Wooden Block Pavements
No full textThe use of waste wood for road light pavements is essential for environmental and economic sustainability.The paper investigates the mechanical performance of pavements built with waste wood elements discarded from Sardinia manufacture (Italy). Without structural value, mainly Sardinian wood is used for combustion and heating due to the characteristics of dimensional irregularity, non-homogeneity, and the presence of defects. Even small urban and forest furniture comes from foreign markets. Landscape reasons, emissions reduction, and environmental integration with the local context could encourage its use if reliable techniques are available.The study first analyzed the structural response of a portion of pavementmade with waste wood bricks (pine and Eucalyptus). Subsequently, a Finite Element simulation of the pavement has been validated with the tests' results. The experimental pavement was created with Interlocked Block Pavement (IBP) technique, using brick elements 13 x 6 x 10 cm. The behavior of the pavement was analyzed in situ with dynamic deflection tests using the Falling Weight Deflectometer test (FWD). Further tests performed in the laboratory investigated the friction of the wood pavement surface. The simulation results show that the wooden pavement elements do not differ substantially from the classic concrete IBP and HMA cracked pavement. The mean deflections are greater than 19%, while the vertical stress on the foundation layer is equivalent. As with the classic concrete IBP, the results largely depend on the bearing capacity of the substrate and the degree of interlocking.Friction tests show good values with mean values of 53 divided by 64 BPN. The most significant values were observed in the elements eucalyptus. The direction of the wood fibers also influences the results: about 3 points in the case of pine and over 7 points in the case of Eucalyptus. The study shows how the use of wood for the pavement with elements is sustainable and practicable due to the minor and low-traffic roads while also guaranteeing permeability and low-cost maintenance
Reproductive performance in three Slovenian sheep breeds with different alleles for the MTNR1A gene
No full textThe aim of the research was to describe the polymorphisms of the MTNR1A gene in three Slovenian sheep breeds, and determine whether these polymorphisms affect reproductive performance. A total of 100 Bovška, 110 Istrian Pramenka, and 108 Jezersko-Solčavska ewes, were used. The rams were placed with the ewes on 10 October (Bovška), and 20 September (Istrian Pramenka). At each farm, the lambing date and number of newborn lambs were recorded to evaluate the fertility rate, number of days from ram placement with ewes to lambing (DRIL), and litter size. The Jezersko-Solčavska rams were maintained with the ewes of the flock throughout the year and data related to lambing during the entire year were recorded. The DNA sequences indicated there were eight nucleotide variations and that in the position g.17355358 was always associated with that in the position g.17355452. For the Bovška breed, there was an association between the G/G genotype in the position g.17355452, and relatively greater fertility (P < 0.05) and a shorter DIRL (P < 0.05). For the Istrian Pramenka breed, the T/T genotype in the position g.17355458 was positively associated with a greater fertility (P < 0.05) and shorter DRIL (P < 0.05). For the Jezersko-Solčavska breed, ewes with the G/G genotype in the position g.17355452 lambed more when there was a decreasing photoperiod whereas the ewes with the A/A genotype lambed more (P < 0.05) during the period when there were increasing photoperiods. The different polymorphisms studied were associated with reproductive performance in the three Slovenian breeds
Pyroclastic Stones as Building Materials in Medieval Romanesque Architecture of Sardinia (Italy): Chemical-Physical Features of Rocks and Associated Alterations
No full textThe paper discusses the chemical-physical-petrographic features and decay processes of San Nicola Church (11th−14th century) building materials, one of the most representative Medieval Churches in Sardinia, stylistically attributable to the Romanesque architecture. The monument was built up into two stages and shows a characteristic size uniformity of the ashlars. The masonry is mainly made up of rhyodacitic pyroclastites belonging to the Sardinian Eocene-Miocene magmatic phase (38–15 My). These volcanic rocks were widely used in Medieval architecture for the excellent workability, but its minero-petrographic features greatly favor the decay, due to the action of chemical-physical alteration processes. Although the alteration degree and macroscopic forms of decay vary from zone to zone in the monument, according to the different compositional features of the volcanic stones, weathering and exposure condition, the pyroclastic rocks are generally affected by greater alteration than other igneous lithotypes, due to their petrographic-volcanological characteristics (e.g., low-medium welding grade, medium-high porosity). The results concerning mineralogical and petrographic features, respectively, carried out by the application of X-Ray Powder Diffraction (XRPD), Optical Microscope (OM), and Scanning Electron Microscope (SEM) techniques, both on fresh building rocks and associated alterations, are here presented and discussed. Furthermore, the relationships between fresh pyroclastites and alteration processes affecting these rocks will be discussed
Breccia-hosted manganese-rich minerals of Alpi Apuane, Italy: a marine, redox-generated deposit
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