The emotional dimension of friendship: Notes on Aristotle’s account of philia in Rhetoric II 4

This article endeavors to give an answer to the question whether and to what extent philia (friendship), as it is treated by Aristotle in Rhetoric II 4, can be considered a genuine emotion as, for example, fear and anger are. Three anomalies are identified in the definition and the account of philia (and of the associated verb philein), which suggest a negative response to the question. However, these anomalies are analysed and explained in terms of the specific notes of philia in order to show that Rhetoric II 4 does allow for a consideration of friendship as a genuine emotion

Multiscale Microstructure for Investigation of Cell–Cell Communication

A multiscale polydimethylsiloxane (PDMS) chip is presented, which provides an array of mesoscale open wells for cell culturing and, as unique feature, an array of microscale 1 µm deep channels to fluidically connect neighboring wells. As demonstrated with SH‐SY5Y cells, the small dimensions of the channels prevent migration of the cell soma but allow physical contacts established by the outgrowth of protoplasmic protrusions between cells in adjacent wells. Another important feature is the chip\u27s mountability on solid substrates, such as glass. This enables the use of substrates previously patterned with biomolecules, as demonstrated by DNA‐directed immobilization of proteins inside the reactor wells. Given the versatile addressability of cells, whether through surface‐bound or inkjet‐based administration of bioactive substances, it is believed that the reactor could be used for research in cell–cell communication networks, for example, in neurodegenerative diseases such as Alzheimer\u27s disease

Fused Deposition Modeling of Microfluidic Chips in Transparent Polystyrene

Polystyrene (PS) is one of the most commonly used thermoplastic materials worldwide and plays a ubiquitous role in today’s biomedical and life science industry and research. The main advantage of PS lies in its facile processability, its excellent optical and mechanical properties, as well as its biocompatibility. However, PS is only rarely used in microfluidic prototyping, since the structuring of PS is mainly performed using industrial-scale replication processes. So far, microfluidic chips in PS have not been accessible to rapid prototyping via 3D printing. In this work, we present, for the first time, 3D printing of transparent PS using fused deposition modeling (FDM). We present FDM printing of transparent PS microfluidic channels with dimensions as small as 300 µm and a high transparency in the region of interest. Furthermore, we demonstrate the fabrication of functional chips such as Tesla-mixer and mixer cascades. Cell culture experiments showed a high cell viability during seven days of culturing, as well as enabling cell adhesion and proliferation. With the aid of this new PS prototyping method, the development of future biomedical microfluidic chips will be significantly accelerated, as it enables using PS from the early academic prototyping all the way to industrial-scale mass replication

Higgs description of two-flavor QCD vacuum

A Higgs description for the QCD vacuum in the limit of two quark flavors is proposed. Complete ``spontaneous breaking'' of color symmetry is realized by condensation of an adjoint quark-antiquark and a quark-quark pair. The vacuum is invariant under isospin symmetry applying color and flavor transformations simultaneously. All elementary excitations acquire integral charges. The dressed microscopic quark and gluon degrees of freedom can be identified with the macroscopic baryon and vector meson degrees of freedom. In addition to the nucleons we find soliton--type fermions with integer isospin. Their presence provides an important test accessible to lattice QCD simulations.Comment: 4 page