Two-photon imaging through a multimode fiber

In this work we demonstrate 3D imaging using two-photon excitation through a 20 cm long multimode optical fiber (MMF) of 350 micrometers diameter. The imaging principle is similar to single photon fluorescence through a MMF, except that a focused femtosecond pulse is delivered and scanned over the sample. In our approach, focusing and scanning through the fiber is accomplished by digital phase conjugation using mode selection by time gating with an ultra-fast reference pulse. The excited two-photon emission is collected through the same fiber. We demonstrate depth sectioning by scanning the focused pulse in a 3D volume over a sample consisting of fluorescent beads suspended in a polymer. The achieved resolution is 1 micrometer laterally and 15 micrometers axially. Scanning is performed over an 80x80 micrometers field of view. To our knowledge, this is the first demonstration of high-resolution three-dimensional imaging using two-photon fluorescence through a multimode fiber

“La devoción de la cruz”: entre la crueldad humana y la clemencia divina

La presencia de la violencia en el teatro de Calderón ha sido observada ya por numerosos investigadores, a pesar de lo cual dicha violencia no ha sido explicada siempre de manera satisfactoria. A la luz de las ideas de Séneca, San Agustín, Santo Tomás de Aquino y San Bernardo de Claraval, en el presente ensayo se analizan las diferentes manifestaciones de violencia y crueldad en “La devoción de la cruz”, una de las primeras obras de Calderón, y que ha sido criticada, a su vez, por quienes no entienden o no simpatizan con la cultura del Barroco español. En contra de la violencia y de la crueldad que se observan en esta obra, Calderón propone como remedio la clemencia, la cual fue considerada como un vicio por Séneca, mientras que San Agustín, Santo Tomás, San Bernardo y los autores más destacados del Siglo de Oro la vieron como una virtud cristiana que debía tenerse en cuenta en la administración de justicia

Quantum localized states in photonic flat-band lattices

The localization of light in flat-band lattices has been recently proposed and experimentally demonstrated in several configurations, assuming a classical description of light. Here, we study the problem of light localization in the quantum regime. We focus on quasi one-dimensional and two-dimensional lattices which exhibit a perfect flat-band inside their linear spectrum. Localized quantum states are constructed as eigenstates of the interaction Hamiltonian with a vanishing eigenvalue and a well defined total photon number. These are superpositions of Fock states with probability amplitudes given by positive as well as negative square roots of multinomial coefficients. The classical picture can be recovered by considering poissonian superpositions of localized quantum states with different total photon number. We also study the separability properties of flat band quantum states and apply them to the transmission of information via multi-core fibers, where these states allow for the total passive suppression of photon crosstalk and exhibit robustness against photon losses. At the end, we propose a novel on-chip setup for the experimental preparation of localized quantum states of light for any number of photons.Comment: 12 pages, 5 figure

Cuatro poemas nuevos de lbn Zamrak: una metáfora gastronómica.

Traducción de cuatro poemas de contenido gastronómico, que Ibn Zamrak escribe para agradecer al sultán, Muhammad y, otros tantos regalos que éste le e¡wía en forma de la/ion o de "pastel de queso", con un análisis del contenido mitológico, religioso y simbólico de esos alimentos. Los 4 poemas proceden de la edición de AI-Nayfar del dfw»n de Ibn Zamrak, recopilado por Yñsuf 111, y hasta ahora desconocido, pues se suponía perdido

Opening up the DNA methylome of dementia

Dementia is a complex clinical condition characterized by several cognitive impairments that interfere with patient independence in executing everyday tasks. Various neurodegenerative disorders have dementia in common among their clinical manifestations. In addition, these diseases, such as Alzheimer's disease, Parkinson's disease, dementia with Lewy bodies and frontotemporal dementia, share molecular alterations at the neuropathological level. In recent years, the field of neuroepigenetics has expanded massively and it is now clear that epigenetic processes, such as DNA methylation, are mechanisms involved in both normal and pathological brain function. Despite the persistent methodological and conceptual caveats, it has been reported that several genes fundamental to the development of neurodegenerative disorders are deregulated by aberrant methylation patterns of their promoters, and even common epigenetic signatures for some dementia-associated pathologies have been identified. Therefore, understanding the epigenetic mechanisms that are altered in dementia, especially those associated with the initial phases, will allow us not only to understand the etiopathology of dementia and its progression but also to design effective therapies to reduce this global public health problem. This review provides an in-depth summary of our current knowledge about DNA methylation in dementia, focusing exclusively on the analyses performed in human brain

Anti-angiogenic therapy based on the binding receptors

This paper deals with a nonlinear system of partial differential equations modeling the effect of an anti-angiogenic therapy based on an agent that binds specific receptors of the endothelial cells. We study the time-dependent problem as well as the stationary problem associated to it.Ministerio de Ciencia e Innovació

Progress on the preparation of nanocrystalline apatites and surface characterization: Overview of fundamental and applied aspects

Nanocrystalline calcium phosphate apatites constitute the main inorganic part of hard tissues, and a growing focus is devoted to prepare synthetic analogs, so-called “biomimetic”, able to precisely mimic the morphological and physico-chemical features of biological apatite compounds. Both from fundamental and applied viewpoints, an accurate characterization of nanocrystalline apatites, including their peculiar surface features, and a deep knowledge of crystallization aspects are prerequisites to attempt understanding mineralization phenomena in vivo as well as for designing innovative bioactive materials that may then find applications in bone tissue engineering, either as self-supported scaffolds and fillers or in the form of coatings, but also in other domains such as drug delivery or else medical imaging. Also,interfacial phenomena are of prime importance for getting a better insight of biomineralization and for following the behavior of biomaterials in or close to their final conditions of use. In this view,both adsorption and ion exchange represent essential processes involving the surface of apatite nanocrystals, possibly doped with foreign elements or functionalized with organic molecules of interest. In this review paper, we will address these various points in details based on a large literature survey. We will also underline the fundamental physico-chemical and behavioral differences that exist between nanocrystalline apatites (whether of biological origin or their synthetic biomimetic analogs) and stoichiometric hydroxyapatite

Disparate Impact on Immigrant and Latino/a Students in Texas: Unequal Funding, School Closures, and Dropout Status

Educational trends illustrate that the academic performance of immigrants exceeds their co-ethnic and native-born counterparts. For example, when examining cognitive test scores of Mexican-origin students by generational status the highest achievements belong to firstgeneration (i.e., immigrants) students, followed by second-generation (i.e., students with one or two immigrant parents), and lastly third (i.e., native-born) and later generations, accounting for socioeconomic status, English proficiency, and institutional factors (Morales & Saenz, 2007). Indeed, if the Mexican-origin population resembled (non-Hispanic) whites in terms of generational status the white-Mexican educational gap would widen (Morales & Saenz, 2007). Even though the immigrant population has demonstrated that they can exceed academically there are several structural factors working against their educational integration. Below we discuss the disparate impact of unequal funding and school closures that disproportionately impacts marginalized populations such as immigrant students, institutional decision-making encouraging the "pushing out" of immigrants from the educational system, and we use census data to show the high percentages of immigrants represented among people between the ages 16 to 24 who dropped out status in Texas.Educatio

An angiogenesis model with nonlinear chemotactic response and flux at the tumor boundary

In this paper we consider a parabolic problem as well as its stationary counterpart of a model arising in angiogenesis. The problem includes a chemotaxis type term and a nonlinear boundary condition at the tumor boundary. We show that the parabolic problem admits a unique positive global in time solution. Moreover, by bifurcation methods, we show the existence of coexistence states and also we study the local stability of the semi-trivial states.Ministerio de Educación y Cienci