Risposte fisiologiche e biochimiche di cloni di pioppo cresciuti in presenza di cadmio e fumigati con ozono

Le piante si trovano frequentemente a vivere in un contesto ambientale caratterizzato dalla presenza simultanea di stress di varia origine. Lo studio delle possibili interazioni tra diversi agenti stressanti e dei meccanismi che sottendono le risposte della pianta a stress combinati rappresenta quindi un campo di indagine quanto mai attuale, sebbene relativamente ancora poco esplorato. Sia l’ozono troposferico (O3) che il cadmio (Cd) sono due inquinanti altamente fitotossici capaci di generare stress ossidativo nei tessuti vegetali, determinando alterazioni sia nell’attività degli enzimi antiossidanti sia nel livello di metaboliti detossificanti solubili con conseguente diminuzione della capacità di scavenging delle specie reattive dell’ossigeno (ROS) prodotte dal normale metabolismo cellulare, che quindi possono accumularsi a livelli tossici. La presente tesi si prefigge lo scopo di indagare se la presenza di cadmio nel suolo sia in grado di influenzare la risposta delle piante ad un’esposizione cronica all’ozono ed in caso affermativo se tale influenza risulti in un’amplificazione o in una riduzione della risposta all’inquinante atmosferico. A tale fine, piante di due cloni di pioppo (I-214 ed Eridano), diversamente sensibili all’O3, cresciute su terreno trattato con 0, 50 e 150 mg Kg-1 di Cd, sono state esposte per 15 giorni a concentrazioni di ozono realistiche (60 ppb di O3 per 5 ore al giorno). L'interesse è stato rivolto alla valutazione dell’effetto indotto dalla presenza dei due fattori di stress sull’assorbimento e traslocazione del Cd e di altri cationi e anioni indispensabili per la crescita della pianta, sui parametri relativi alla crescita dei diversi organi della pianta (foglie, germogli e radici), sulla produzione di H2O2 e NO e sulla funzionalità dell'apparato fotosintetico. I risultati hanno mostrato come entrambi i cloni fossero in grado di assorbire e traslocare il Cd alla parte aerea della pianta e come l’accumulo del metallo determinasse una riduzione significativa del peso secco dei tre organi esaminati. L’esposizione all’O3 interferiva negativamente con il processo di accumulo del Cd nella parte epigea della pianta di entrambi i cloni, secondo un meccanismo non completamente spiegabile dalla diminuzione della traspirazione e quindi del trasporto del Cd per via xilematica. Un effetto antagonista tra i due fattori di stress era evidente anche relativamente all’attivazione del ciclo fotoprotettivo delle xantofille, che infatti risultava stimolato dall’O3, mentre il Cd esercitava, su tale parametro, un effetto nullo (clone I-214) o negativo (in Eridano). La presenza di Cd determinava un accumulo di H2O2 nei tessuti fogliari molto più marcato di quanto indotto dall’O3, strettamente correlato alla concentrazione di Cd fogliare. Anche l’NO era positivamente stimolato dal fattore Cd, mentre la successiva esposizione all’O3 non incrementava l’accumulo di NO Cd-dipendente in Eridano e addirittura portava ad una sua diminuzione in I-214. In conclusione, i risultati hanno evidenziato un’interazione non sempre univoca tra i due fattori di stress, in dipendenza sia del parametro analizzato sia del clone in esame, a testimonianza della complessità del fenomeno di risposta delle piante agli stress ambientali. Plants are often exposed to many different stress and so became important to studied interactions between two or more stress and mechanisms of response of plants. Tropospheric ozone (O3) and cadmium (Cd) are two important phytotoxic pollutants, because they generate oxidative stress in plant tissues by inducing an over-production of reactive oxygen species (ROS) or by decreasing enzymatic and non-enzymatic antioxidants and thus they produce an imbalances in the antioxidant defences of plants. The present work aims at evaluating if the presence of cadmium in soil can influence the response of plants to a chronic exposure to ozone. In order to do that, plants of two poplar clones (I-214 and Eridano) grown in soil contaminated by 0, 50 or 150 mg Kg-1 of Cd, are been exposed to realistic concentration of O3 for 15 days (60 ppb for 5 hours every day). The attention has been focused on the evaluation the effects on the uptake and traslocation of cations and anions, on the plant growth, on the production of H2O2 and NO and on the photosynthetic apparatus functionality. Results showed that the presence of Cd in soil induced a remarkable increase in cadmium levels in the different organs examined and a decrease in their dry weight. Instead, O3 caused a reduction in Cd accumulation in leaves and shoots, but this effect wasn’t explain by a reduction of traspiration rate. Cd and O3 showed an antagonist effect on the activation of xantophyll cycle, in fact the presence of O3 stimulated it, whereas Cd had a negative effect (in Eridano) or no effect (in I-214) on this cycle. The growth of poplar plants with Cd induced the H2O2 accumulation in leaves, in proportion with Cd concentration in leaves, whereas O3 had a lesser effect on the concentration of this molecule. NO was stimulated by Cd, but O3 didn’t increase NO concentration in Eridano and it reduced the accumulation of this molecule in I-214. In conclusion, results showed different kind of interaction between Cd and O3, in fact mechanisms of plant’s response to different stress are very complex

Bent crystal selection and assembling for the LAUE project

For the first time, with the Laue project, bent crystals are being used for focusing photons in the 80-300 keV energy range. The advantage is their high reflectivity and better Point Spread Function with respect to the mosaic flat crystals. Simulations have already shown their excellent focusing capability which makes them the best candidates for a Laue lens whose sensitivity is also driven by the size of the focused spot. Selected crystals are Germanium (perfect, (111)) and Gallium Arsenide (mosaic, (220)) with 40 m curvature radius to get a spherical lens with 20 m long focal length. A lens petal is being built. We report the measurement technique by which we are able to estimate the exact curvature of each tile within a few percent of uncertainty and their diffraction efficiency. We also discuss some results.Comment: 9 pages, 15 figures, SPIE conference vol. 8861 (2013

Self-presentation and emotional contagion on Facebook: new experimental measures of profiles' emotional coherence

Social Networks allow users to self-present by sharing personal contents with others which may add comments. Recent studies highlighted how the emotions expressed in a post affect others' posts, eliciting a congruent emotion. So far, no studies have yet investigated the emotional coherence between wall posts and its comments. This research evaluated posts and comments mood of Facebook profiles, analyzing their linguistic features, and a measure to assess an excessive self-presentation was introduced. Two new experimental measures were built, describing the emotional loading (positive and negative) of posts and comments, and the mood correspondence between them was evaluated. The profiles "empathy", the mood coherence between post and comments, was used to investigate the relation between an excessive self-presentation and the emotional coherence of a profile. Participants publish a higher average number of posts with positive mood. To publish an emotional post corresponds to get more likes, comments and receive a coherent mood of comments, confirming the emotional contagion effect reported in literature. Finally, the more empathetic profiles are characterized by an excessive self-presentation, having more posts, and receiving more comments and likes. To publish emotional contents appears to be functional to receive more comments and likes, fulfilling needs of attention-seeking.Comment: Submitted to Complexit

3-Tesla Magnetic Resonance Imaging vs Endorectal Ultrasound in the preoperative staging of rectal cancer: a correlation analysis

Purpose: To evaluate the agreement between endorectal ultrasound (ERUS) and magnetic resonance imaging (MRI) in preoperative staging of rectal cancer. Materials and Methods: Fifty patients with rectal cancer underwent ERUS and 3-Tesla MRI for preoperative staging. With both imaging techniques were evaluated the following features: lesion site, tumour longitudinal extent, distance between lesion and puborectalis muscle, levator ani muscles infiltration, depth of extramural spread, mesorectal lymph nodes involvement and pelvic organs infiltration. MRI evaluated also the following features: maximum thickness of the lesion, distance between lesion and mesorectal fascia and overcoming of the peritoneal reflection. All MR examinations were evaluated by two experienced radiologists. The correlation between MRI and ultrasound data was calculated for each parameter using the Spearman rank test and considering statistically significant p-values <0.05. The interobserver agreement for MR imaging was assessed by using the Cohen’s kappa statistics. Eleven patients underwent directly to surgical resection without neoadjuvant therapy and the surgical resection specimen was used as standard of reference for determination of depth of invasion (T stage) and perirectal nodal involvement (N stage). Results: ERUS and MRI showed a statistically significant correlation for the lesion site (MRI observer A vs ERUS: rs=0.873, p<0.000001/ MRI observer B vs ERUS: rs=0.8485, p<0.000001), the tumour longitudinal extent (MRI observer A vs ERUS: rs=0.378, p=0.010393/ MRI observer B vs ERUS: rs=0.3794, p=0.010131), the distance between lesion and puborectalis muscle (MRI observer A vs ERUS: rs=0.7954, p<0.000001/ MRI observer B vs ERUS: rs=0.7989, p<0.000001) and the depth of extramural spread (MRI observer A vs ERUS: rs=0.5107, p=0.000149/ MRI observer B vs ERUS: rs=0.5046, p=0.000186). Moreover, TRUS and MRI were able to demonstrate the levator ani muscles infiltration with an overall agreement of 82% for MRI reader A and 80% for MRI reader B, the lymph nodes involvement with an agreement of 68% for MRI reader A and 76% for MRI reader B and the pelvic organs infiltration with an agreement of 80% for both MRI reader. MRI allowed, however, the evaluation of other very important features for the correct staging of rectal cancer, in particular the distance between lesion and mesorectal fascia. The interobserver agreement between MRI reader A and B was almost perfect for the lesion site and the distance between lesion and puborectalis muscle, there was a substantial agreement for the tumour longitudinal extent, the depth of extramural spread and the maximum thickness of the lesion; instead there was only a moderate agreement for the distance between lesion and mesorectal fascia. There was also an agreement between the two observers of 100% for the pelvic organ involvement, of 96% for the overcoming of the anterior peritoneal reflection, of 88% for the mesorectal lymph nodes involvement and of 82% for the levator ani muscles infiltration. Conclusion: The good agreement between MRI and TRUS in preoperative staging of rectal cancer argues in favor of the use of MRI, because it also allows a more comprehensive local assessment

Variations in physiological and biochemical traits of oak seedlings grown under drought and ozone stress

Despite the huge biodiversity characterizing the Mediterranean environment, environmental constraints, such as high sunlight and high temperatures alongside with dry periods, makes plant survival hard. In addition, high irradiance leads to increasing ozone (O3 ) concentrations in ambient air. In this era of global warming, it is necessary to understand the mechanisms that allow native species to tolerate these environmental constraints and how such mechanisms interact. Three Mediterranean oak species (Quercus ilex, Q. pubescens and Q. cerris) with different features (drought tolerant, evergreen or deciduous species) were selected to assess their biometrical, physiological and biochemical responses under drought and/or O3 stress (80-100 nl l(-1) of O3 for 5 h d(-1) for 77 consecutive days). Leaf visible injury appeared only under drought stress (alone or combined with O3 ) in all three species. Drought × O3 induced strong reductions in leaf dry weight in Q. pubescens and Q. cerris (-70 and -75%, respectively). Alterations in physiological (i.e. decrease in maximum carboxylation rate) and biochemical parameters (i.e. increase in proline content and build-up of malondialdehyde by-products) occurred in all the three species, although drought represented the major determinant. Q. ilex and Q. pubescens, which co-occur in dry environments, were more tolerant to drought and drought × O3 . Quercus ilex was the species in which oxidative stress occurred only when drought was applied with O3 . High plasticity at a biochemical level (i.e. proline content) and evergreen habitus are likely on the basis of the higher tolerance of Q. ilex

Living in a Mediterranean city in 2050: broadleaf or evergreen ‘citizens’?

The predicted effects of global change (GC) will be exacerbated in the more densely populated cities of the future, especially in the Mediterranean basin where some environmental cues, such as drought and tropospheric ozone (O3) pollution, already mine seriously plant survival. Physiological and biochemical responses of a Mediterranean, evergreen, isohydric plant species (Quercus ilex) were compared to those of a sympatric, deciduous, anisohydric species (Q. pubescens) under severe drought (20% of the effective daily evapotranspiration) and/or chronic O3 exposure (80 ppb for 5 h dayâ1 for 28 consecutive days) to test which one was more successful in those highly limiting conditions. Results show that (i) the lower reduction of total leaf biomass of Q. ilex as compared to Q. pubescens when subjected to drought and drought à O3 (on average â59 vs â70%, respectively); (ii) the steeper decline of photosynthesis found in Q. pubescens under drought (â87 vs â81%) and drought à O3 (â69 vs â59%, respectively); (iii) the increments of malondialdehyde (MDA) by-products found only in drought-stressed Q. pubescens; (iv) the impact of O3, found only in Q. pubescens leaves and MDA, can be considered the best probes of the superiority of Q. ilex to counteract the effect of mild-severe drought and O3 stress. Also, an antagonistic effect was found when drought and O3 were applied simultaneously, as usually happens during typical Mediterranean summers. Our dataset suggests that on future, the urban greening should be wisely pondered on the ability of trees to cope the most impacting factors of GC, and in particular their simultaneity

Cross‐Talk between Physiological and Metabolic Adjustments Adopted by Quercus cerris to Mitigate the Effects of Severe Drought and Realistic Future Ozone Concentrations

Global climate change represents a moving target for plant acclimation and/or adaptation, especially in the Mediterranean basin. In this study, the interactions of severe drought (20% of the effective daily evapotranspiration) and O3 fumigation (80 ppb, 5 h day−1, for 28 consecutive days) on (i) photosynthetic performance, (ii) cell membrane stability, (iii) hydric relations, (iv) accumulation of compatible solutes, and (v) lipophilic antioxidant compounds were investigated in young Quercus cerris plants. In addition to the typical drought-induced stomatal closure, imposition of water withholding dramatically influenced the profile of stress-associated metabolites, i.e., abscisic acid (ABA), proline, and lipophilic antioxidants. However, plants were not able to delay or prevent the negative effects of water deficit, the greatest impacting factor in this study. This translated into a steep decline of photosynthetic efficiency, leaf hydration, and membrane fluidity and permeability. When water stress was coupled with O3, plants orchestrated cross-talk among ABA, proline, and sugar in fully-expanded mature leaves, partially leading to a premature senescenc

Patient posture for blood collection by venipuncture: recall for standardization after 28 years

Although data about the effect of posture on routine hematological testing were published 28 years ago, this pre-analytical issue has not been standardized so far. This study was planned to evaluate whether postural changes influence the results of hematology testing. METHODS: A complete blood count was performed in 19 healthy volunteers after 25min in the supine position, 20min in a sitting position and 20min stationary standing in an upright position. RESULTS: The change from supine to sitting position caused clinically significant increases in the hemoglobin, hematocrit and red blood cell count. Furthermore, the change from supine to standing caused clinically significant increases in the hemoglobin, hematocrit, red blood cell, leukocyte, neutrophil, lymphocyte, basophil and platelet counts, and mean platelet volume, and that from sitting to standing caused clinically significant increases in hemoglobin, hematocrit, and red blood cell, leukocyte, neutrophil and lymphocyte counts. CONCLUSION: The results of this investigation provide further support to the notion that effort should be made to achieve widespread standardization in the practice of phlebotomy, including patient posture. Copyright \ua9 2017 Associa\ue7\ue3o Brasileira de Hematologia, Hemoterapia e Terapia Celular. Published by Elsevier Editora Ltda. All rights reserved

Physical realization of a quantum spin liquid based on a novel frustration mechanism

Unlike conventional magnets where the magnetic moments are partially or completely static in the ground state, in a quantum spin liquid they remain in collective motion down to the lowest temperatures. The importance of this state is that it is coherent and highly entangled without breaking local symmetries. Such phenomena is usually sought in simple lattices where antiferromagnetic interactions and/or anisotropies that favor specific alignments of the magnetic moments are "frustrated" by lattice geometries incompatible with such order e.g. triangular structures. Despite an extensive search among such compounds, experimental realizations remain very few. Here we describe the investigation of a novel, unexplored magnetic system consisting of strong ferromagnetic and weaker antiferromagnetic isotropic interactions as realized by the compound Ca$_{10}$Cr$_7$O$_{28}$. Despite its exotic structure we show both experimentally and theoretically that it displays all the features expected of a quantum spin liquid including coherent spin dynamics in the ground state and the complete absence of static magnetism.Comment: Modified version accepted in Nature Physic