479 research outputs found

    An investigation of the roles furan versus thiophene π-bridges play in donor–π-acceptor porphyrin based DSSCs

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    Dye-sensitized solar cells (DSSCs) continue to attract interest due to their lower cost production compared to silicon based solar cells and their improving power conversion efficiencies. Porphyrin-based sensitizers have become an important sub-class due to their strong absorption characteristics in the visible region, convenient modulation of properties through synthetic manipulation and class-leading power conversion efficiencies. In this article, we report the synthesis and characterization of two porphyrin-based dyes and their application as sensitizers in DSSCs. A thiophene and a furan moiety have been incorporated into the push–pull architecture as a π-bridge, allowing the systematic investigation of how these moieties influence the physical properties of the dyes and the performance of their resulting DSSCs. A significant difference in PCEs has been observed, with the furan containing dye (PorF, PCE = 4.5%) being more efficient than the thiophene-based analogue (PorT, PCE = 3.6%) in conjunction with the iodide/triiodide redox electrolyte

    Metabolic syndrome and idiopathic sudden sensori-neural hearing loss

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    The purpose of this study was to evaluate the association between the presence of Metabolic Syndrome (MetS) and idiopathic sudden sensorineural hearing loss (ISSHL) and the impact of MetS on recovery of patients with ISSHL. 39 Patients with ISSHL and 44 controls were enrolled in this study. Demographic, clinical characteristics and hearing recovery were evaluated. MetS was defined according to the diagnostic criteria of International Diabetes Federation (IDF) consensus definition. Patients affected by ISSHL presented a body mass index (BMI), waist circumference, waist hip ratio (WHR), fasting glucose and blood pressure significantly higher compared to controls. Considering patients with central obesity, 5 controls and 15 ISSHL patients met the criteria of MetS. According to Siegel criteria, a complete or partial recovery was observed in 60% of patients with MetS and in 91,66% of patients without MetS. MetS was associated with ISSHL and this association negatively influenced the hearing recovery of these patients

    Benzo-dipteridine derivatives as organic cathodes for Li- and Na-ion batteries

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    Organic-based electrodes for Li- and Na-ion batteries present attractive alternatives to commonly applied inorganic counterparts which can often carry with them supply-chain risks, safety concerns with thermal runaway, and adverse environmental impact. The ability to chemically direct the structure of organic electrodes through control over functional groups is of particular importance, as this provides a route to fine-tune electrochemical performance parameters. Here, we report two benzo-dipteridine derivatives, BF-Me2 and BF-H2, as high-capacity electrodes for use in Li- and Na-ion batteries. These moieties permit binding of multiple Li-ions per molecule while simultaneously ensuring low solubility in the supporting electrolyte, often a precluding issue with organic electrodes. Both display excellent electrochemical stability, with discharge capacities of 142 and 182 mAh g–1 after 100 cycles at a C/10 rate and Coulombic efficiencies of 96% and ∌ 100% demonstrated for BF-Me2 and BF-H2, respectively. The application of a Na-ion cell has also been demonstrated, showing discharge capacities of 88.8 and 137 mAh g–1 after 100 cycles at a C/2 rate for BF-Me2 and BF-H2, respectively. This work provides an encouraging precedent for these and related structures to provide versatile, high-energy density, and long cycle-life electrochemical energy storage materials

    Adhesion of platelets to colon cancer cells is necessary to promote tumor development in xenograft, genetic and inflammation models

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    Platelets represent the linkage between tissue damage and inflammatory response with a putative role in tumorigenesis. Given the importance of the microenvironment in colon cancer development, we elucidated the eventual role of platelets‐cancer cells crosstalk in in vivo colon cancer models. To evaluate the involvement of platelets in intestinal tumorigenesis, we first analyzed if the ablation of ÎČ‐integrin P‐selectin that drives platelets‐cell adhesion, would contribute to platelets‐colon cancer cell interaction and drive cancer progression. In a xenograft tumor model, we observed that when tumors are inoculated with platelets, the ablation of P‐selectin significantly reduced tumor growth compared to control platelets. Furthermore, in genetic models, as well as in chronic colitis‐associated colorectal carcinogenesis, P‐selectin ablated mice displayed a significant reduction in tumor number and size compared to control mice. Taken together, our data highlights the importance of platelets in the tumor microenvironment for intestinal tumorigenesis. These results support the hypothesis that a strategy aimed to inhibit platelets adhesion to tumor cells are able to block tumor growth and could represent a novel therapeutic approach to colon cancer treatment

    Solitary waves of nonlinear nonintegrable equations

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    Our goal is to find closed form analytic expressions for the solitary waves of nonlinear nonintegrable partial differential equations. The suitable methods, which can only be nonperturbative, are classified in two classes. In the first class, which includes the well known so-called truncation methods, one \textit{a priori} assumes a given class of expressions (polynomials, etc) for the unknown solution; the involved work can easily be done by hand but all solutions outside the given class are surely missed. In the second class, instead of searching an expression for the solution, one builds an intermediate, equivalent information, namely the \textit{first order} autonomous ODE satisfied by the solitary wave; in principle, no solution can be missed, but the involved work requires computer algebra. We present the application to the cubic and quintic complex one-dimensional Ginzburg-Landau equations, and to the Kuramoto-Sivashinsky equation.Comment: 28 pages, chapter in book "Dissipative solitons", ed. Akhmediev, to appea

    On elliptic solutions of the cubic complex one-dimensional Ginzburg-Landau equation

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    The cubic complex one-dimensional Ginzburg-Landau equation is considered. Using the Hone's method, based on the use of the Laurent-series solutions and the residue theorem, we have proved that this equation has neither elliptic standing wave nor elliptic travelling wave solutions. This result amplifies the Hone's result, that this equation has no elliptic travelling wave solutions.Comment: LaTeX, 12 page

    Meromorphic traveling wave solutions of the complex cubic-quintic Ginzburg-Landau equation

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    We look for singlevalued solutions of the squared modulus M of the traveling wave reduction of the complex cubic-quintic Ginzburg-Landau equation. Using Clunie's lemma, we first prove that any meromorphic solution M is necessarily elliptic or degenerate elliptic. We then give the two canonical decompositions of the new elliptic solution recently obtained by the subequation method.Comment: 14 pages, no figure, to appear, Acta Applicandae Mathematica
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