530 research outputs found

    On the origin of Phase Transitions in the absence of Symmetry-Breaking

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    In this paper we investigate the Hamiltonian dynamics of a lattice gauge model in three spatial dimension. Our model Hamiltonian is defined on the basis of a continuum version of a duality transformation of a three dimensional Ising model. The system so obtained undergoes a thermodynamic phase transition in the absence of symmetry-breaking. Besides the well known use of quantities like the Wilson loop we show how else the phase transition in such a kind of models can be detected. It is found that the first order phase transition undergone by this model is characterised according to an Ehrenfest-like classification of phase transitions applied to the configurational entropy. On the basis of the topological theory of phase transitions, it is discussed why the seemingly divergent behaviour of the third derivative of configurational entropy can be considered as the "shadow" of some suitable topological transition of certain submanifolds of configuration space.Comment: 31 pages, 9 figure

    Ethyl acetate extract from Cistus x incanus L. leaves enriched in myricetin and quercetin derivatives, inhibits inflammatory mediators and activates Nrf2/HO-1 pathway in LPS-stimulated RAW 264.7 macrophages.

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    Abstract Cistus x incanus L. is a Mediterranean evergreen shrub used in folk medicine for the treatment of inflammatory disorders but the underlying mechanisms are not fully understood. We therefore investigated the anti-inflammatory effects of an ethyl acetate fraction (EAF) from C. x incanus L. leaves on lipopolysaccharide (LPS) activated RAW 264.7 macrophages. HPLC analysis revealed myricetin and quercetin derivatives to be the major compounds in EAF; EAF up to 1 µM of total phenolic content, was not cytotoxic and inhibited the mRNA expression of interleukin-6 (IL-6) and cyclooxygenase-2 (COX-2) (p < 0.05) and the production of prostaglandins E2 (PGE2) (p < 0.05). Meanwhile, EAF triggered the mRNA expression of interleukin-10 (IL-10) and elicited the nuclear translocation of nuclear factor erythroid 2-related factor 2 (Nrf2), as well as the expression of its main target gene, heme oxygenase-1 (HO-1) (p < 0.05). These data indicate that EAF attenuates experimental inflammation via the inhibition of proinflammatory mediators and at least in part, by the activation of Nrf2/HO-1 pathway. These effects are likely due to myricetin and quercetin derivatives but the role of other, less abundant components cannot be excluded. Further studies to confirm the relevance of our findings in animal models and to highlight the relative contribution of each component to the anti-inflammatory activity of EAF should be conducted

    UV radiation promotes flavonoid biosynthesis, while negatively affecting the biosynthesis and de-epoxidation of xanthophylls: consequence for photoprotection?

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    There is evidence that UV radiation may detrimentally affect the biosynthesis of carotenoids, particularly de-epoxided xanthophylls, while strongly promoting phenylpropanoid, particularly flavonoid biosynthesis in a range of taxa. Here we tested the hypothesis that mesophyll flavonoids might protect chloroplasts from UV-induced photo-oxidative damage, by partially compensating for the UV-induced depression of xanthophyll biosynthesis. To test this hypothesis we grew two members of the Oleaceae family, Ligustrum vulgare L. and Phillyrea latifolia L., under either partial shading or fully exposed to sunlight, in the presence or in the absence of UV radiation. The examined species, which display very similar flavonoid composition, largely differ in their ability to limit the transmission of UV and visible light through the leaf and, hence, in the accumulation of flavonoids in mesophyll cells. We conducted measurements of photosynthesis, chlorophyll a fluorescence kinetics, the concentrations of individual carotenoids and phenylpropanoids at the level of whole-leaf, as well as the content of epidermal flavonoids. We also performed multispectral fluorescence micro-imaging to unveil the intra-cellular distribution of flavonoids in mesophyll cells. UV radiation decreased the concentration of carotenoids, particularly of xanthophylls, while greatly promoting the accumulation of flavonoids in palisade parenchyma cells. These effects were much greater in L. vulgare than in P. latifolia. UV radiation significantly inhibited the de-epoxidation of xanthophyll cycle pigments, while enhancing the concentration of luteolin, and particularly of quercetin glycosides. Flavonoids accumulated in the vacuole and the chloroplasts in palisade cells proximal to the adaxial epidermis. We hypothesize that flavonoids might complement the photo-protective functions of xanthophylls in the chloroplasts of mesophyll cells exposed to the greatest doses of UV radiation. However, UV radiation might result in adaxial mesophyll cells being less effective in dissipating the excess of radiant energy, e.g., by decreasing their capacity of thermal dissipation of excess visible light in the chloroplast

    Dissecting Adaptation Mechanisms to Contrasting Solar Irradiance in the Mediterranean Shrub Cistus incanus

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    Molecular mechanisms that are the base of the strategies adopted by Mediterranean plants to cope with the challenges imposed by limited or excessive solar radiation during the summer season have received limited attention. In our study, conducted on C. incanus plants growing in the shade or in full sunlight, we performed measurements of relevant physiological traits, such as leaf water potential, gas exchange and PSII photochemistry, RNA-Seq with de-novo assembly, and the analysis of differentially expressed genes. We also identified and quantified photosynthetic pigments, abscisic acid, and flavonoids. Here, we show major mechanisms regulating light perception and signaling which, in turn, sustain the shade avoidance syndrome displayed by the &lsquo;sun loving&rsquo; C. incanus. We offer clear evidence of the detrimental effects of excessive light on both the assembly and the stability of PSII, and the activation of a suite of both repair and effective antioxidant mechanisms in sun-adapted leaves. For instance, our study supports the view of major antioxidant functions of zeaxanthin in sunny plants concomitantly challenged by severe drought stress. Finally, our study confirms the multiple functions served by flavonoids, both flavonols and flavanols, in the adaptive mechanisms of plants to the environmental pressures associated to Mediterranean climate

    Multi-point monitoring of nitrous oxide emissions in three full-scale conventional activated sludge tanks in Europe

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    The large global warming potential of nitrous oxide (N2O) is currently of general concern for the water industry, especially in view of a new regulatory framework concerning the carbon footprint of water resource recovery facilities (WRRFs). N2O can be generated through different biological pathways and from different treatment steps of a WRRF. The use of generic emission factors (EF) for quantifying the emissions of WRRFs is discouraged. This is due to the number of different factors that can affect how much, when and where N2O is emitted from WRRFs. The spatial and temporal variability of three WRRFs in Europe using comparable technologies is presented. An economically feasible and user-friendly method for accounting for the contribution of anoxic zones via direct gas emission measurements was proven. The investigation provided new insights into the contribution from the anoxic zones versus the aerobic zones of biological WRRF tanks and proved the unsuitability of the use of a single EF for the three WRRFs. Dedicated campaigns for N2O emissions assessment are to be advised. However, similarities in the EF magnitude can be found considering treatment strategy and influent water composition

    Metabolic plasticity in the hygrophyte Moringa oleifera exposed to water stress

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    Over the past decades, introduction of many fast-growing hygrophilic, and economically valuable plants into xeric environments has occurred. However, production and even survival of these species may be threatened by harsh climatic conditions unless an effective physiological and metabolic plasticity is available. Moringa oleifera Lam., a multipurpose tree originating from humid sub-tropical regions of India, is widely cultivated in many arid countries because of its multiple uses. We tested whether M. oleifera can adjust primary and secondary metabolism to efficiently cope with increasing water stress. It is shown that M. oleifera possesses an effective isohydric behavior. Water stress induced a quick and strong stomatal closure, driven by abscisic acid (ABA) accumulation, and leading to photosynthesis inhibition with consequent negative effects on biomass production. However, photochemistry was not impaired and maximal fluorescence and saturating photosynthesis remained unaffected in stressed leaves. We report for the first time that M. oleifera produces isoprene, and show that isoprene emission increased three-fold during stress progression. It is proposed that higher isoprene biosynthesis helps leaves cope with water stress through its antioxidant or membrane stabilizing action, and also indicates a general MEP (methylerythritol 4-phosphate) pathway activation that further helps protect photosynthesis under water stress. Increased concentrations of antioxidant flavonoids were also observed in water stressed leaves, and probably cooperate in limiting irreversible effects of the stress in M. oleifera leaves. The observed metabolic and phenotypic plasticity may facilitate the establishment of M. oleifera in xeric environments, sustaining the economic and environmental value of this plant

    The Effectiveness of Coping Strategies in the Latent First Stage of Labour: A Systematic Review

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    The latent phase of labour is defined as a period of time marked by painful uterine contractions and variable changes of the cervix, including some degree of cervical effacement and a slow dilatation up to 5 cm [1]..

    Colorectal Cancer Stage at Diagnosis Before vs During the COVID-19 Pandemic in Italy

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    Càncer colorectal; Pandèmia de COVID-19Cáncer colorrectal; Pandemia de COVID-19Colorectal cancer; COVID-19 pandemicImportance Delays in screening programs and the reluctance of patients to seek medical attention because of the outbreak of SARS-CoV-2 could be associated with the risk of more advanced colorectal cancers at diagnosis. Objective To evaluate whether the SARS-CoV-2 pandemic was associated with more advanced oncologic stage and change in clinical presentation for patients with colorectal cancer. Design, Setting, and Participants This retrospective, multicenter cohort study included all 17 938 adult patients who underwent surgery for colorectal cancer from March 1, 2020, to December 31, 2021 (pandemic period), and from January 1, 2018, to February 29, 2020 (prepandemic period), in 81 participating centers in Italy, including tertiary centers and community hospitals. Follow-up was 30 days from surgery. Exposures Any type of surgical procedure for colorectal cancer, including explorative surgery, palliative procedures, and atypical or segmental resections. Main Outcomes and Measures The primary outcome was advanced stage of colorectal cancer at diagnosis. Secondary outcomes were distant metastasis, T4 stage, aggressive biology (defined as cancer with at least 1 of the following characteristics: signet ring cells, mucinous tumor, budding, lymphovascular invasion, perineural invasion, and lymphangitis), stenotic lesion, emergency surgery, and palliative surgery. The independent association between the pandemic period and the outcomes was assessed using multivariate random-effects logistic regression, with hospital as the cluster variable. Results A total of 17 938 patients (10 007 men [55.8%]; mean [SD] age, 70.6 [12.2] years) underwent surgery for colorectal cancer: 7796 (43.5%) during the pandemic period and 10 142 (56.5%) during the prepandemic period. Logistic regression indicated that the pandemic period was significantly associated with an increased rate of advanced-stage colorectal cancer (odds ratio [OR], 1.07; 95% CI, 1.01-1.13; P = .03), aggressive biology (OR, 1.32; 95% CI, 1.15-1.53; P < .001), and stenotic lesions (OR, 1.15; 95% CI, 1.01-1.31; P = .03). Conclusions and Relevance This cohort study suggests a significant association between the SARS-CoV-2 pandemic and the risk of a more advanced oncologic stage at diagnosis among patients undergoing surgery for colorectal cancer and might indicate a potential reduction of survival for these patients

    Differential expression of the fractalkine chemokine receptor (CX3CR1) in human monocytes during differentiation

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    Circulating monocytes (Mos) may continuously repopulate macrophage (MAC) or dendritic cell (DC) populations to maintain homeostasis. MACs and DCs are specialized cells that play different and complementary immunological functions. Accordingly, they present distinct migratory properties. Specifically, whereas MACs largely remain in tissues, DCs are capable of migrating from peripheral tissues to lymphoid organs. The aim of this work was to analyze the expression of the fractalkine receptor (CX3CR1) during the monocytic differentiation process. Freshly isolated Mos express high levels of both CX3CR1 mRNA and protein. During the Mo differentiation process, CX3CR1 is downregulated in both DCs and MACs. However, MACs showed significantly higher CX3CR1 expression levels than did DC. We also observed an antagonistic CX3CR1 regulation by interferon (IFN)-γ and interleukin (IL)-4 during MAC activation through the classical and alternative MAC pathways, respectively. IFN-γ inhibited the loss of CX3CR1, but IL-4 induced it. Additionally, we demonstrated an association between CX3CR1 expression and apoptosis prevention by soluble fractalkine (sCX3CL1) in Mos, DCs and MACs. This is the first report demonstrating sequential and differential CX3CR1 modulation during Mo differentiation. Most importantly, we demonstrated a functional link between CX3CR1 expression and cell survival in the presence of sCX3CL1.Fil: Panek, Cecilia Analía. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; Argentina. Academia Nacional de Medicina de Buenos Aires; ArgentinaFil: Ramos, Maria Victoria. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; Argentina. Academia Nacional de Medicina de Buenos Aires; ArgentinaFil: Mejias, María Pilar. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; Argentina. Academia Nacional de Medicina de Buenos Aires; ArgentinaFil: Abrey Recalde, Maria Jimena. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; Argentina. Academia Nacional de Medicina de Buenos Aires; ArgentinaFil: Fernández Brando, Romina Jimena. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; Argentina. Academia Nacional de Medicina de Buenos Aires; ArgentinaFil: Gori, María Soledad. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; Argentina. Academia Nacional de Medicina de Buenos Aires; ArgentinaFil: Salamone, Gabriela Veronica. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; Argentina. Academia Nacional de Medicina de Buenos Aires; ArgentinaFil: Palermo, Marina Sandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; Argentina. Academia Nacional de Medicina de Buenos Aires; Argentin
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