99 research outputs found

    Prospecting effective Yang-Mills-Higgs models for the asymptotic confining flux tube

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    In this work, we analyze a large class of effective Yang-Mills-Higgs models constructed in terms of adjoint scalars. In particular, we reproduce asymptotic properties of the confining string, suggested by lattice simulations of SU(N)SU(N) pure Yang-Mills theory, in models that are stable in the whole range of Higgs-field mass parameters. These properties include NN-ality, Abelian-like flux-tube profiles, independence of the profiles with the NN-ality of the quark representation, and Casimir scaling. We find that although these models are formulated in terms of many fields and possible Higgs potentials, a collective behavior can be established in a large region of parameter space, where the desired asymptotic behavior is realized.Comment: 24 pages, 1 figur

    Tensile strength essay comparing three different platelet-rich fibrin membranes (L-PRF, A-PRF, and A-PRF plus): a mechanical and structural in vitro evaluation

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    Predictable outcomes intended by the application of PRF (platelet-rich fibrin) derivative membranes have created a lack of consideration for their consistency and functional integrity. This study aimed to compare the mechanical properties through tensile strength and analyze the structural organization among the membranes produced by L-PRF (leukocyte platelet-rich fibrin), A-PRF (advanced platelet-rich fibrin), and A-PRF+ (advanced platelet-rich fibrin plus) (original protocols) that varied in centrifugation speed and time. L-PRF (n = 12), A-PRF (n = 19), and A-PRF+ (n = 13) membranes were submitted to a traction test, evaluating the maximum and average traction. For maximum traction, 0.0020, 0.0022, and 0.0010 N·mm−2 were obtained for A-PRF, A-PRF+, and L-PRF, respectively; regarding the average resistance to traction, 0.0012, 0.0015, and 0.006 N·mm−2 were obtained, respectively (A-PRF+ > A-PRF > L-PRF). For all groups studied, significant results were found. In the surface morphology observations through SEM, the L-PRF matrix showed a highly compact surface with thick fibers present within interfibrous areas with the apparent destruction of red blood cells and leukocytes. The A-PRF protocol showed a dense matrix composed of thin and elongated fibers that seemed to follow a preferential and orientated direction in which the platelets were well-adhered. Porosity was also evident with a large diameter of the interfibrous spaces whereas A-PRF+ was the most porous platelet concentrate with the greatest fiber abundance and cell preservation. Thus, this study concluded that A-PRF+ produced membranes with significant and higher maximum traction results, indicating a better viscoelastic strength when stretched by two opposing forces.info:eu-repo/semantics/publishedVersio

    Fall Armyworm, Spodoptera frugiperda (JE Smith) (Lepidoptera: Noctuidae), Female Moths Respond to Herbivore-Induced Corn Volatiles

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    In response to herbivore attack, plants release herbivore-induced plant volatiles (HIPVs) that represent important chemical cues for herbivore natural enemies. Additionally, HIPVs have been shown to mediate other ecological interactions with herbivores. Differently from natural enemies that are generally attracted to HIPVs, herbivores can be either attracted or repelled depending on several biological and ecological parameters. Our study aimed to assess the olfactory response of fall armyworm-mated female moths toward odors released by mechanically and herbivore-induced corn at different time intervals. Results showed that female moths strongly respond to corn volatiles, although fresh damaged corn odors (0-1 h) are not recognized by moths. Moreover, females preferred volatiles released by undamaged plant over herbivore-induced plants at 5-6 h. This preference for undamaged plants may reflect an adaptive strategy of moths to avoid competitors and natural enemies for their offspring. We discussed our results based on knowledge about corn volatile release pattern and raise possible explanations for fall armyworm moth behavior.INCT Semioquimicos na AgriculturaINCT Semioquimicos na AgriculturaCNPqCNPqFAPESPFapes

    Microbially induced pseudotraces from a Pantanal soda lake, Brazil : Alternative interpretations for Ediacaran simple trails and their limits

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    Despite the absence of metazoans, structures resembling animal traces are common in a soda lake from the western Brazil Pantanal wetland. Pantanal soda lakes are ecologically extreme environments that preclude complex life, allowing extremophiles to flourish. Direct observation indicates that these structures are pseudotraces, representing groove marks that result from the interaction of wave-transported floating rafts of epibenthic microbial mat fragments with the substrate. Variations in wind/wave direction and intensity result in marks of different size and morphology. The most common pseudotraces are simple and slightly curved, narrow grooves (type 1), whereas others are straight and present raised lateral ridges (type 2). Both are V-shaped in cross section. Type 3 comprises long, sinuous, shallow grooves, displaying internal crescentic laminated infill and U-shaped cross section. The similarity of these pseudotraces to Ediacaran structures usually interpreted as animal trace fossils suggests that care should be exercised in their analysis. A set of criteria is proposed to differentiate microbially induced pseudotraces from trace fossils. Analysis of Ediacaran structures needs to be performed on a case-by-case basis, taking into account morphology, orientation, and preservation style of the structure, sedimentary environment, and presence or absence of microbial mats.Centro de Investigaciones Geológica

    A2 Noradrenergic Lesions Prevent Renal Sympathoinhibition Induced by Hypernatremia in Rats

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    Renal vasodilation and sympathoinhibition are recognized responses induced by hypernatremia, but the central neural pathways underlying such responses are not yet entirely understood. Several findings suggest that A2 noradrenergic neurons, which are found in the nucleus of the solitary tract (NTS), play a role in the pathways that contribute to body fluid homeostasis and cardiovascular regulation. The purpose of this study was to determine the effects of selective lesions of A2 neurons on the renal vasodilation and sympathoinhibition induced by hypertonic saline (HS) infusion. Male Wistar rats (280–350 g) received an injection into the NTS of anti-dopamine-beta-hydroxylase-saporin (A2 lesion; 6.3 ng in 60 nl; n = 6) or free saporin (sham; 1.3 ng in 60 nl; n = 7). Two weeks later, the rats were anesthetized (urethane 1.2 g⋅kg−1 b.wt., i.v.) and the blood pressure, renal blood flow (RBF), renal vascular conductance (RVC) and renal sympathetic nerve activity (RSNA) were recorded. In sham rats, the HS infusion (3 M NaCl, 1.8 ml⋅kg−1 b.wt., i.v.) induced transient hypertension (peak at 10 min after HS; 9±2.7 mmHg) and increases in the RBF and RVC (141±7.9% and 140±7.9% of baseline at 60 min after HS, respectively). HS infusion also decreased the RSNA (−45±5.0% at 10 min after HS) throughout the experimental period. In the A2-lesioned rats, the HS infusion induced transient hypertension (6±1.4 mmHg at 10 min after HS), as well as increased RBF and RVC (133±5.2% and 134±6.9% of baseline at 60 min after HS, respectively). However, in these rats, the HS failed to reduce the RSNA (115±3.1% at 10 min after HS). The extent of the catecholaminergic lesions was confirmed by immunocytochemistry. These results suggest that A2 noradrenergic neurons are components of the neural pathways regulating the composition of the extracellular fluid compartment and are selectively involved in hypernatremia-induced sympathoinhibition

    Polypodium leucotomos targets multiple aspects of oral carcinogenesis and it is a potential antitumor phytotherapy against tongue cancer growth

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    Introduction: Oral cancer refers to malignant tumors, of which 90% are squamous cell carcinomas (OSCCs). These malignancies exhibit rapid progression, poor prognosis, and often mutilating therapeutical approaches. The determination of a prophylactic and/or therapeutic antitumor role of the polyphenolic extract Polypodium leucotomos(PL) would be relevant in developing new tools for prevention and treatment.Methods: We aimed to determine the antitumor effect of PL by treating OSCC cell lines with PL metabolites and evaluating its action during OSCC progression in vivo.Results: PL treatment successfully impaired cell cycling and proliferation, migration, and invasion, enhanced apoptosis, and modulated macrophage polarization associated with the tumoral immune-inflammatory response of tongue cancer cell lines (TSCC). PL treatment significantly decreased the expression of MMP1 (p < 0.01) and MMP2 (p < 0.001), and increased the expression of TIMP1 (p < 0.001) and TIMP2 (p < 0.0001) in these cells. The mesenchymal-epithelial transition phenotype was promoted in cells treated with PL, through upregulation of E-CAD (p < 0.001) and reduction of N-CAD (p < 0.05). PL restrained OSCC progression in vivo by inhibiting tumor volume growth and decreasing the number of severe dysplasia lesions and squamous cell carcinomas. Ki-67 was significantly higher expressed in tongue tissues of animals not treated with PL(p < 0.05), and a notable reduction in Bcl2 (p < 0.05) and Pcna (p < 0.05) cell proliferation-associated genes was found in dysplastic lesions and TSCCs of PL-treated mice. Finally, N-cad(Cdh2), Vim, and Twist were significantly reduced in tongue tissues treated with PL.Conclusion: PL significantly decreased OSCC carcinogenic processes in vitro and inhibited tumor progression in vivo. PL also appears to contribute to the modulation of immune-inflammatory oral tumor-associated responses. Taken together, these results suggest that PL plays an important antitumor role in processes associated with oral carcinogenesis and may be a potential phytotherapeutic target for the prevention and/or adjuvant treatment of TSCC

    Photography-based taxonomy is inadequate, unnecessary, and potentially harmful for biological sciences

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    The question whether taxonomic descriptions naming new animal species without type specimen(s) deposited in collections should be accepted for publication by scientific journals and allowed by the Code has already been discussed in Zootaxa (Dubois & Nemésio 2007; Donegan 2008, 2009; Nemésio 2009a–b; Dubois 2009; Gentile & Snell 2009; Minelli 2009; Cianferoni & Bartolozzi 2016; Amorim et al. 2016). This question was again raised in a letter supported by 35 signatories published in the journal Nature (Pape et al. 2016) on 15 September 2016. On 25 September 2016, the following rebuttal (strictly limited to 300 words as per the editorial rules of Nature) was submitted to Nature, which on 18 October 2016 refused to publish it. As we think this problem is a very important one for zoological taxonomy, this text is published here exactly as submitted to Nature, followed by the list of the 493 taxonomists and collection-based researchers who signed it in the short time span from 20 September to 6 October 2016
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