Two distinct filopodia populations at the growth cone allow to sense nanotopographical extracellular matrix cues to guide neurite outgrowth

BACKGROUND The process of neurite outgrowth is the initial step in producing the neuronal processes that wire the brain. Current models about neurite outgrowth have been derived from classic two-dimensional (2D) cell culture systems, which do not recapitulate the topographical cues that are present in the extracellular matrix (ECM) in vivo. Here, we explore how ECM nanotopography influences neurite outgrowth. METHODOLOGY/PRINCIPAL FINDINGS We show that, when the ECM protein laminin is presented on a line pattern with nanometric size features, it leads to orientation of neurite outgrowth along the line pattern. This is also coupled with a robust increase in neurite length. The sensing mechanism that allows neurite orientation occurs through a highly stereotypical growth cone behavior involving two filopodia populations. Non-aligned filopodia on the distal part of the growth cone scan the pattern in a lateral back and forth motion and are highly unstable. Filopodia at the growth cone tip align with the line substrate, are stabilized by an F-actin rich cytoskeleton and enable steady neurite extension. This stabilization event most likely occurs by integration of signals emanating from non-aligned and aligned filopodia which sense different extent of adhesion surface on the line pattern. In contrast, on the 2D substrate only unstable filopodia are observed at the growth cone, leading to frequent neurite collapse events and less efficient outgrowth. CONCLUSIONS/SIGNIFICANCE We propose that a constant crosstalk between both filopodia populations allows stochastic sensing of nanotopographical ECM cues, leading to oriented and steady neurite outgrowth. Our work provides insight in how neuronal growth cones can sense geometric ECM cues. This has not been accessible previously using routine 2D culture systems.

Does gender-fair language pay off? The social perception of professions from a cross-linguistic perspective

In many languages, masculine forms (e.g., German Lehrer, “teachers, masc.”) have traditionally been used to refer to both women and men, although feminine forms are available, too. Feminine-masculine word pairs (e.g., German Lehrerinnen und Lehrer, “teachers, fem. and teachers, masc.”) are recommended as gender-fair alternatives. A large body of empirical research documents that the use of gender-fair forms instead of masculine forms has a substantial impact on mental representations. Masculine forms activate more male representations even when used in a generic sense, whereas word pairs (e.g., German Lehrerinnen und Lehrer, “teachers, fem. and teachers, masc.”) lead to a higher cognitive inclusion of women (i.e., visibility of women). Some recent studies, however, have also shown that in a professional context word pairs may be associated with lesser status. The present research is the first to investigate both effects within a single paradigm. A cross-linguistic (Italian and German) study with 391 participants shows that word pairs help to avoid a male bias in the gender-typing of professions and increase women's visibility; at the same time, they decrease the estimated salaries of typically feminine professions (but do not affect perceived social status or competence). This potential payoff has implications for language policies aiming at gender-fairness.

Conventionalism and the World as Bare Sense-Data

We are confident of many of the judgements we make as to what sorts of alterations the members of nature’s kinds can survive, and what sorts of events mark the ends of their existences. But is our confidence based on empirical observation of nature’s kinds and their members? Conventionalists deny that we can learn empirically which properties are essential to the members of nature’s kinds. Judgements of sameness in kind between members, and of numerical sameness of a member across time, merely project our conventions of individuation. Our confidence is warranted because apart from those conventions there are no phenomena of kind-sameness or of numerical sameness across time. There is just “stuff” displaying properties. This paper argues that conventionalists can assign no properties to the “stuff” beyond immediate phenomenal properties. Consequently they cannot explain how each of us comes to be able to wield “our conventions”.

Ein Symposium der Forschung [Rezension] : Occident and Orient. Being Studies in Semitic Philology and Literature, Jewish History, Philosophy and Folklore in the widest sense. In Honour of Haham Dr. Gasters 80. Birthday ed. by Bruno Schindler and A. Marmorstein. Taylors Foreign Press, London 1937

-ss.

The American : a practical book for self-instruction to speak, read and write the English language ; each English word is translated in Hebrew

by B. Goldgar and I. Mirovitch

Contrafatur Was Gestalt etliche Siebēberger Raete sein gerichtet Wordē so Widder ihren hernn eine greuliche Morterey Forgenō Zuhaben Wie Die Ziffer Erkler : Anō 95

Aus: [Continuator temporis quinquennalis?]

Eigentlicher Abriß der Reichstags-Solennitet : so den 3., 13. Sept. diß 1640 Jahrs in Regenspurg bey eröfnuḡ d' proposition angestelt vnd gehalten wordē

Bibliograph. Nachweis: Paas P-2083

De Europische Insecten : Naauwkeurig onderzogt, na't leven geschildert, en in print gebragt door Maria Sibilla Merian; Met een korte Beschryving, waar in door haar gehandelt word van der Rupsen begin, Voedzel en wonderbare Verandering; En Ook Vertoont Word De Oorspronk, Spys en Gestalt-verwisseling, de Tyd, Plaats en Eigenschappen der Rupzen, Uiltjes, Vliegen en andere diergelyke bloedeloose Beesjes; Hier Is Nog Bygevoegt Een naauwkeurige Beschryving van de Planten, in dit Werk voorkomende; ... In't Frans beschreven door J. Marret, Medicinæ Doctor, En door een voornaam Liefhebber in't Nederduits vertaalt

Die Illustrationen sind Kupferstiche

Las enfermedades mentales según Tomás de Aquino : sobre las enfermedades (mentales) en sentido estricto

Continuando un artículo anterior en el que se definió el concepto de enfermedad, en orden al esclarecimiento del de enfermedad mental, en el presente estudio se desarrolla el tema de aquellas que pueden ser llamadas enfermedades en el estricto sentido del término. En un primer parágrafo, se mencionan los trastornos que son mencionados por Santo Tomás, y se los explica colocándolos en el contexto de la medicina medieval, con particular referencia al Canon de Medicina de Avicena. En un segundo parágrafo, se desarrolla el tema de las enfermedades psicosomáticas, es decir aquellas causadas por una “pasión animal". Se deja para un tercer artículo el esclarecimiento de la naturaleza de lo que el Aquinate llama “aegritudo animalis".