Continuous ultrafiltration/diafiltration using a 3D‐printed two membrane single pass module

A 3D printed ultrafiltration/diafiltration (UF/DF) module is presented allowing the continuous, simultaneous concentration of retained (bio‐)molecules and reduction or exchange of the salt buffer. Differing from the single‐pass UF concepts known from the literature, DF operation does not require the application of several steps or units with intermediating dilution. In contrast, the developed module uses two membranes confining the section in which the molecules are concentrated while the sample is passing. Simultaneously to this concentration process, the two membranes allow a perpendicular in and outflow of DF buffer reducing the salt content in this section. The module showed the continuous concentration of a dissolved protein up to a factor of 4.6 while reducing the salt concentration down to 47% of the initial concentration along a flow path length of only 5 cm. Due to single‐pass operation the module shows concentration polarization effects reducing the effective permeability of the applied membrane in case of higher concentration factors. However, because of its simple design and the capability to simultaneously run UF and DF processes in a single module, the development could be economically beneficial for small scale UF/DF applications

KP line solitons and Tamari lattices

The KP-II equation possesses a class of line soliton solutions which can be qualitatively described via a tropical approximation as a chain of rooted binary trees, except at "critical" events where a transition to a different rooted binary tree takes place. We prove that these correspond to maximal chains in Tamari lattices (which are poset structures on associahedra). We further derive results that allow to compute details of the evolution, including the critical events. Moreover, we present some insights into the structure of the more general line soliton solutions. All this yields a characterization of possible evolutions of line soliton patterns on a shallow fluid surface (provided that the KP-II approximation applies).Comment: 49 pages, 36 figures, second version: section 4 expande

Development of an Online General Biology Open Educational Resource (OER) Laboratory Manual

Currently, many academic institutions are using one or more variations of online modalities due to the COVID-19 pandemic, and science educators face a unique challenge with distance-learning laboratories. Many resources to engage students in virtual, interactive laboratory activities exist, but we found that high costs and/or overlooked content left gaps for several topics typically taught in a general, introductory biology course for undergraduate biology majors (e.g., organismal biology). Additionally, resources for an online lab must be identified and curated from multiple sources, requiring intense demands on the instructors’ time. To meet this need and to overcome the financial burden of high-cost lab manuals or software, we developed, piloted, and revised a series of online general biology lab exercises. We have published these exercises as an Open Educational Resource (OER) digital laboratory manual under the Creative Commons License Agreement, and they are accessible online via Manifold, Creative Commons, and the CUNY Academic Works portal

Honesty mediates the relationship between serotonin and reaction to unfairness

How does one deal with unfair behaviors? This subject has long been investigated by various disciplines including philosophy, psychology, economics, and biology. However, our reactions to unfairness differ from one individual to another. Experimental economics studies using the ultimatum game (UG), in which players must decide whether to accept or reject fair or unfair offers, have also shown that there are substantial individual differences in reaction to unfairness. However, little is known about psychological as well as neurobiological mechanisms of this observation. We combined a molecular imaging technique, an economics game, and a personality inventory to elucidate the neurobiological mechanism of heterogeneous reactions to unfairness. Contrary to the common belief that aggressive personalities (impulsivity or hostility) are related to the high rejection rate of unfair offers in UG, we found that individuals with apparently peaceful personalities (straightforwardness and trust) rejected more often and were engaged in personally costly forms of retaliation. Furthermore, individuals with a low level of serotonin transporters in the dorsal raphe nucleus (DRN) are honest and trustful, and thus cannot tolerate unfairness, being candid in expressing their frustrations. In other words, higher central serotonin transmission might allow us to behave adroitly and opportunistically, being good at playing games while pursuing self-interest. We provide unique neurobiological evidence to account for individual differences of reaction to unfairness

General Biology 2 Laboratory Manual

Currently, many academic institutions are using one or more variations of online modalities due to the Covid-19 pandemic, and science educators face a unique challenge with distance-learning laboratories. Many resources to engage students in virtual, interactive laboratory activities exist, but we found that high costs and/or overlooked content left gaps for several topics typically taught in a general, introductory biology course for undergraduate biology majors (e.g., organismal biology). Additionally, resources for an online lab must be identified and curated from multiple sources, requiring intense demands on the instructors’ time. To meet this need and to overcome the financial burden of high-cost lab manuals or software, we developed, piloted, and revised a series of online general biology lab exercises. We have published these exercises as an Open Educational Resource (OER) digital laboratory manual under the Creative Commons License Agreement, and they are accessible online via Manifold, Creative Commons, and the CUNY Academic Works portal