Non-noble electrocatalysts for alkaline fuel cells

The doping of solid phase precursors followed by pyrolysis or the copyrolysis of gas phase precursors has allowed us to produce catalysts with good activity toward oxygen reduction. Efforts are currently underway to better understand the reasons for the catalytic activity of the bulk doped catalysts with a view toward further improving their activity

Polarization Correlations in Pair Production from Charged and Neutral Strings

Polarization correlations of $e^{+}e^{-}$ pair productions from charged and neutral Nambu strings are investigated, via photon and graviton emissions, respectively and explicit expressions for their corresponding probabilities are derived and found to be \textit{speed} dependent. The strings are taken to be circularly oscillating closed strings, as perhaps the simplest solution of the Nambu action. In the extreme relativistic case, these probabilities coincide, but, in general, are different, and such inquiries, in principle, indicate whether the string is charged or uncharged. It is remarkable that these dynamical relativistic quantum field theory calculations lead to a clear violation of Local Hidden Variables theories.Comment: 6 pages, no figure, LaTeX with ws-mpla.cl

Transdermal Delivery of Functional Collagen \u3cem\u3eVia\u3c/em\u3e Polyvinylpyrrolidone Microneedles

Collagen makes up a large proportion of the human body, particularly the skin. As the body ages, collagen content decreases, resulting in wrinkled skin and decreased wound healing capabilities. This paper presents a method of delivering type I collagen into porcine and human skin utilizing a polyvinylpyrrolidone microneedle delivery system. The microneedle patches were made with concentrations of 1, 2, 4, and 8% type I collagen (w/w). Microneedle structures and the distribution of collagen were characterized using scanning electron microscopy and confocal microscopy. Patches were then applied on the porcine and human skin, and their effectiveness was examined using fluorescence microscopy. The results illustrate that this microneedle delivery system is effective in delivering collagen I into the epidermis and dermis of porcine and human skin. Since the technique presented in this paper is quick, safe, effective and easy, it can be considered as a new collagen delivery method for cosmetic and therapeutic applications

The uses of Connes and Kreimer's algebraic formulation of renormalization theory

We show how, modulo the distinction between the antipode and the "twisted" or "renormalized" antipode, Connes and Kreimer's algebraic paradigm trivializes the proofs of equivalence of the (corrected) Dyson-Salam, Bogoliubov-Parasiuk-Hepp and Zimmermann procedures for renormalizing Feynman amplitudes. We discuss the outlook for a parallel simplification of computations in quantum field theory, stemming from the same algebraic approach.Comment: 15 pages, Latex. Minor changes, typos fixed, 2 references adde

A theorem on the photographic process in Special Relativity. The train paradox revisited

The purpose of this letter is to show, on the one hand, how the so-called train paradox could be resolved directly without appealing to non-linear Lorentz transformations. The resolution is established in the most general case of curvilinear motion with a variable speed train. On the other hand, we formulate a theorem on the photographic process of two moving objects with relativistic effects.Comment: 7 pages, 1 figur

Analysis of BRCA1 and RAD51C promoter methylation in italian families at high-risk of breast and ovarian cancer

Previous studies on breast and ovarian carcinoma (BC and OC) revealed constitutional BRCA1 and RAD51C promoter hypermethylation as epigenetic alterations leading to tumor predisposition. Nevertheless, the impact of epimutations at these genes is still debated. One hundred and eight women affected by BC, OC, or both and considered at very high risk of carrying BRCA1 germline mutations were studied. All samples were negative for pathogenic variants or variants of uncertain significance at BRCA testing. Quantitative BRCA1 and RAD51C promoter methylation analyses were performed by Epityper mass spectrometry on peripheral blood samples and results were compared with those in controls. All the 108 analyzed cases showed methylation levels at the BRCA1/RAD51C promoter comparable with controls. Mean methylation levels (\ub1 stdev) at the BRCA1 promoter were 4.3% (\ub1 1.4%) and 4.4% (\ub1 1.4%) in controls and patients, respectively (p > 0.05; t-test); mean methylation levels (\ub1 stdev) at the RAD51C promoter were 4.3% (\ub1 0.9%) and 3.7% (\ub1 0.9%) in controls and patients, respectively (p > 0.05; t-test). Based on these observations; the analysis of constitutional methylation at promoters of these genes does not seem to substantially improve the definition of cancer risks in patients. These data support the idea that epimutations represent a very rare event in high-risk BC/OC populations

Scattering of two-level atoms by delta lasers: Exactly solvable models in atom optics

We study the scattering of two-level atoms at narrow laser fields, modeled by a $\delta$-shape intensity profile. The unique properties of these potentials allow us to give simple analytic solutions for one or two field zones. Several applications are studied: a single $\delta$-laser may serve as a detector model for atom detection and arrival-time measurements, either by means of fluorescence or variations in occupation probabilities. We show that, in principle, this ideal detector can measure the particle density, the quantum mechanical flux, arrival time distributions or local kinetic energy densities. Moreover, two spatially separated $\delta$-lasers are used to investigate quantized-motion effects on Ramsey interferometry.Comment: 11 pages, 5 figure

Combinatorial Hopf algebras in quantum field theory I

This manuscript stands at the interface between combinatorial Hopf algebra theory and renormalization theory. Its plan is as follows: Section 1 is the introduction, and contains as well an elementary invitation to the subject. The rest of part I, comprising Sections 2-6, is devoted to the basics of Hopf algebra theory and examples, in ascending level of complexity. Part II turns around the all-important Faa di Bruno Hopf algebra. Section 7 contains a first, direct approach to it. Section 8 gives applications of the Faa di Bruno algebra to quantum field theory and Lagrange reversion. Section 9 rederives the related Connes-Moscovici algebras. In Part III we turn to the Connes-Kreimer Hopf algebras of Feynman graphs and, more generally, to incidence bialgebras. In Section10 we describe the first. Then in Section11 we give a simple derivation of (the properly combinatorial part of) Zimmermann's cancellation-free method, in its original diagrammatic form. In Section 12 general incidence algebras are introduced, and the Faa di Bruno bialgebras are described as incidence bialgebras. In Section 13, deeper lore on Rota's incidence algebras allows us to reinterpret Connes-Kreimer algebras in terms of distributive lattices. Next, the general algebraic-combinatorial proof of the cancellation-free formula for antipodes is ascertained; this is the heart of the paper. The structure results for commutative Hopf algebras are found in Sections 14 and 15. An outlook section very briefly reviews the coalgebraic aspects of quantization and the Rota-Baxter map in renormalization.Comment: 94 pages, LaTeX figures, precisions made, typos corrected, more references adde

Characterization of an Italian founder mutation in the RING-finger domain of BRCA1

The identification of founder mutations in cancer predisposing genes is important to improve risk assessment in geographically defined populations, since it may provide specific targets resulting in cost-effective genetic testing. Here, we report the characterization of the BRCA1 c.190T>C (p.Cys64Arg) mutation, mapped to the RING-finger domain coding region, that we detected in 43 hereditary breast/ovarian cancer (HBOC) families, for the large part originating from the province of Bergamo (Northern Italy). Haplotype analysis was performed in 21 families, and led to the identification of a shared haplotype extending over three BRCA1-associated marker loci (0.4 cM). Using the DMLE+2.2 software program and regional population demographic data, we were able to estimate the age of the mutation to vary between 3,100 and 3,350 years old. Functional characterization of the mutation was carried out at both transcript and protein level. Reverse transcriptase-PCR analysis on lymphoblastoid cells revealed expression of full length mRNA from the mutant allele. A green fluorescent protein (GFP)-fragment reassembly assay showed that the p.Cys64Arg substitution prevents the binding of the BRCA1 protein to the interacting protein BARD1, in a similar way as proven deleterious mutations in the RING-domain. Overall, 55 of 83 (66%) female mutation carriers had a diagnosis of breast and/or ovarian cancer. Our observations indicate that the BRCA1 c.190T>C is a pathogenic founder mutation present in the Italian population. Further analyses will evaluate whether screening for this mutation can be suggested as an effective strategy for the rapid identification of at-risk individuals in the Bergamo area