8,643 research outputs found

    First teuthid cephalopod from the Lower Jurassic of South America (Neuquén Basin, Argentina)

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    A new species of squid, Teudopsis jeletzkyi n. sp., is described from the Toarcian (Lower Jurassic) of the Los Molles Formation in Neuquen Province, central west Argentina. Fossil squids have thus far been unknown in the Mesozoic of South America. This species is the first record of the Order Teuthida in the Jurassic of South America

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    First teuthid cephalopod from the Lower Jurassic of South America (Neuquén Basin, Argentina)

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    A new species of squid, Teudopsis jeletzkyi n. sp., is described from the Toarcian (Lower Jurassic) of the Los Molles Formation in Neuquen Province, central west Argentina. Fossil squids have thus far been unknown in the Mesozoic of South America. This species is the first record of the Order Teuthida in the Jurassic of South America

    Intrahepatic persistent fetal right umbilical vein: a retrospective study

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    Introduction: To appraise the incidence and value of intrahepatic persistent right umbilical vein (PRUV). Methods: This was a single-center study. Records of all women with a prenatal diagnosis of intrahepatic PRUV were reviewed. The inclusion criteria were women with gestational age greater than 13 weeks of gestation. Exclusion criteria were fetuses with situs abnormalities, due to the hepatic venous ambiguity, and extrahepatic PRUV. The primary outcome was the incidence of intrahepatic PRUV in our cohort. The secondary outcomes were associated malformations. Results: 219/57,079 cases (0.38%) of intrahepatic PRUV were recorded. The mean gestational age at diagnosis was 21.8 ± 2.9 weeks of gestations. PRUV was isolated in the 76.7%, while in 23.3% was associated with other major or minor abnormalities. The most common associated abnormalities were cardiovascular abnormalities (8.7%), followed by genitourinary abnormalities (6.4%), skeletal abnormalities (4.6%), and central nervous system abnormalities (4.1%). Within the cardiovascular abnormalities, the most common one was ventricular septal defect (six cases). Conclusion: In most cases PRUV is an isolated finding. Associated minor or major malformations are presented in the 23.3% of the cases, so this finding should prompt detailed prenatal assessment of the fetus, with particular regard to cardiovascular system

    Modeling of the Rheological Properties of Asphalt Binder and Asphalt Mortar Containing Recycled Asphalt Material

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    Abstract The use of recycled materials in asphalt pavements increased significantly over the years, determining well known environmental and economic benefits. Many research agencies and road authorities evaluated the impact of Recycled Asphalt Pavement (RAP) on pavement performance. Nevertheless, the mechanism governing the interaction between virgin asphalt binder and aged RAP binder is not well understood. In this paper, the effect of RAP on the rheological properties of asphalt binders and mortars is experimentally evaluated, and theoretically modeled with the objective of defining a relationship between the linear viscoelastic (LVE) properties of binders and those of the corresponding mortars. Three asphalt binder types, obtained by blending a hard and a soft binder at three different percentages, were mixed with three different contents of a Selected fraction of Recycled Asphalt Pavement, called SRAP, for preparing the asphalt mortar samples. Dynamic Shear Rheomether tests were performed on binders and mortars to determining the complex modulus over a wide range of temperatures and frequencies. The rheological properties of the compound of virgin and RAP binder were evaluated by using a new approach based on a modified version of the Nielsen model, avoiding the extraction and recovery method. The results were then modelled by using the analogical 2S2P1D model, consisting of one spring, two parabolic and one-dashpot elements combined in series and then assembled together with a second spring in parallel. Based on test results, a simple experimental relationship between the characteristic times of the binder and the percentage of RAP in the mortar was found

    A novel two-stage kinetic model for surface DBD simulations in air

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    In this work, a novel 0D model for the evaluation of O-3 and NO2 produced by a surface dielectric barrier discharge (SDBD) in a closed environment is presented. The model is composed by two coupled sub-models, a discharge sub-model and an afterglow one. The first one, simulating the discharge regime and consequently including electron impact reactions, aims to calculate the production rates of a set of key species (atomic oxygen, excited states of molecular oxygen and molecular nitrogen). These latter are the input of the afterglow sub-model, that simulates the afterglow regime. We introduce a methodology to relate the production rates of the above mentioned species to the input power of the SDBD reactor. The simulation results are validated by a comparison with experimental data from absorption spectroscopy. The experimental measurements are carried out as follows. First, the discharge is turned on until the NO2 number density reaches steady state. Then, the discharge is turned off for several minutes. Finally, the discharge is turned on again to observe the effects of the NO2 concentration on ozone dynamics. The entire process is done without opening the box. The system operating in all the above-listed conditions is simulated for three different levels of input power

    Tuning the polymorphism of the anti-VEGF G-rich V7t1 aptamer by covalent dimeric constructs

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    In the optimization process of nucleic acid aptamers, increased affinity and/or activity are generally searched by exploring structural analogues of the lead compound. In many cases, promising results have been obtained by dimerization of the starting aptamer. Here we studied a focused set of covalent dimers of the G-quadruplex (G4) forming anti-Vascular Endothelial Growth Factor (VEGF) V7t1 aptamer with the aim of identifying derivatives with improved properties. In the design of these covalent dimers, connecting linkers of different chemical nature, maintaining the same polarity along the strand or inverting it, have been introduced. These dimeric aptamers have been investigated using several biophysical techniques to disclose the conformational behavior, molecularity and thermal stability of the structures formed in different buffers. This in-depth biophysical characterization revealed the formation of stable G4 structures, however in some cases accompanied by alternative tridimensional arrangements. When tested for their VEGF165 binding and antiproliferative activity in comparison with V7t1, these covalent dimers showed slightly lower binding ability to the target protein but similar if not slightly higher antiproliferative activity on human breast adenocarcinoma MCF-7 cells. These results provide useful information for the design of improved dimeric aptamers based on further optimization of the linker joining the two consecutive V7t1 sequences

    Darwin: el hombre y su obra, en relación con el contexto geólogico y paleontológico de la época

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    Il Grano di Pietro Gaudenzi. Stato di conservazione e problematiche di intervento

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    L\u2019opera Il grano (\u201cdipinto murale su intonaco applicato a masonite\u201d, cm 249x434, Pinacoteca del Museo Civico \u201cAla Ponzone\u201d di Cremona) viene realizzata da Pietro Gaudenzi nel 1940 per la seconda edizione del Premio Cremona istituito da Roberto Farinacci nel 1939, a seguito della necessit\ue0 di rafforzare il mercato e le quotazioni d\u2019arte attraverso mostre e premi che richiamassero i valori dell\u2019ideologia fascista in campo artistico. I cartoni preparatori degli affreschi eseguiti da Gaudenzi a Rodi, raccolti nella recente mostra (2015) Pietro Gaudenzi: gli affreschi perduti del Castello dei Cavalieri a Rodi [1], ritenuti l\u2019ultima testimonianza rimasta delle pitture murali che occupavano la Sala del pane e la Sala della famiglia del Castello - ricostruito dagli italiani dal 1936 al 1940 - evocano il trittico che vincer\ue0 il premio Cremona nel 1940. Diversamente dalle tecniche sperimentali che hanno caratterizzato molte delle opere del ritorno alla tradizione decorativa murale, Gaudenzi dipinge il trittico su un intonaco composto da un aggregato silicatico e calce. Il disegno \ue8 stato eseguito tramite incisioni dirette da cartoni preparatori, successivamente ripassate con un tratto bruno, i colori sono stati scelti tra quelli tradizionalmente usati per questo tipo di pittura, unitamente a pigmenti inorganici minerali sintetici in uso a partire dal XIX secolo. L\u2019opera, realizzata su pannelli rigidi (masonite), risulta \u2013 sul fondo \u2013 impermeabile al vapore acqueo che, in situazioni di variazione dei parametri microclimatici ambientali e a causa delle frequenti movimentazioni del dipinto, provoca sollevamenti localizzati di forme tondeggianti (a bolla). La pellicola pittorica, resa leggermente plastica dalla vernice, si rigonfia distaccandosi dal supporto in quantit\ue0 talvolta, estese. I conseguenti necessari interventi di manutenzione, mirati al consolidamento dei sollevamenti, risultano particolarmente complessi per l\u2019impossibilit\ue0 di intervenire dal retro: la necessit\ue0 di attraversare il film protettivo e penetrare la pellicola pittorica in assenza di crettature ha evidenziato l\u2019estrema fragilit\ue0 sia del film pittorico che della materia sottostante. Lo studio presenta alcune metodologie di intervento utilizzate, nel tempo, per consolidare il trittico. La possibilit\ue0 di poter analizzare alcuni microframmenti ha richiesto l\u2019applicazione di una strategia analitica basata sull\u2019uso di microscopi e microsonde. La successione degli strati tecnici \ue8 stata definita in microscopia ottica (OM) ed elettronica a scansione (SEM), su \u201ccross section\u201d. Le tessiture e la composizione chimica dei leganti e dei pigmenti dei singoli strati sono state determinate utilizzando un sistema di microanalisi in dispersione di energia (EDS) e in spettrofotometria FT-IR. Questi dati integrano le informazioni ottenute con le tecniche non invasive d\u2019immagine (luminescenza UV, riflettografia IR e riprese IR in falso colore) e puntuali (XRF) realizzate in situ

    Therapeutic sequences in patients with grade 1−2 neuroendocrine tumors (NET): an observational multicenter study from the ELIOS group

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    Purpose: Many different treatments are suggested by guidelines to treat grade 1−2 (G1−G2) neuroendocrine tumors (NET). However, a precise therapeutic algorithm has not yet been established. This study aims at identifying and comparing the main therapeutic sequences in G1−G2 NET. Methods: A retrospective observational Italian multicenter study was designed to collect data on therapeutic sequences in NET. Median progression-free survival (PFS) was compared between therapeutic sequences, as well as the number and grade of side effects and the rate of dose reduction/treatment discontinuation. Results: Among 1182 patients with neuroendocrine neoplasia included in the ELIOS database, 131 G1–G2 gastroenteropancreatic, lung and unknown primary NET, unresectable or persistent/relapsing after surgery, treated with ≥2 systemic treatments, were included. Four main therapeutic sequences were identified in 99 patients: (A) somatostatin analogs (SSA) standard dose to SSA high dose (n = 36), (B) SSA to everolimus (n = 31), (C) SSA to chemotherapy (n = 17), (D) SSA to peptide receptor radionuclide therapy (PRRT) (n = 15). Median PFS of the second-line treatment was not reached in sequence A, 33 months in sequence B, 20 months in sequence C, 30 months in sequence D (p = 0.16). Both total number and severity of side effects were significantly higher in sequences B and C than A and D (p = 0.04), as well as the rate of dose reduction/discontinuation (p = 0.03). Conclusions: SSA followed by SSA high dose, everolimus, chemotherapy or PRRT represent the main therapeutic sequences in G1−G2 NET. Median PFS was not significantly different between sequences. However, the sequences with SSA high dose or PRRT seem to be better tolerated than sequences with everolimus or chemotherapy
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