Zusammenhänge zwischen der Basisinnovation der Informations- und Kommunikationstechnologien und der räumlich-funktionalen Entwicklung der Europäischen Stadt

Zu Beginn der gesellschaftlichen Etablierung der Informations- und Kommunikationstechnologien in den 1990er Jahren wurde die gänzliche Trennung von realem und virtuellem Raum sowie die Auflösung der gebauten Stadt befürchtet. Es folgte eine Phase der intensiven Betrachtung und Auseinandersetzung mit den Entwicklungen. In den Jahren nach der Jahrtausendwende wandelte sich dieses Verständnis hin zu einem Wechselverhältnis: Teile lösen sich auf, andere bedingen sich gegenseitig. Grundlegend scheinen sich reale und virtuelle Welte zu überlagern und miteinander zu verschmelzen. Welche Auswirkungen die Digitalisierung auf den Stadtraum tatsächlich genommen hat, ist bisher jedoch weitgehend stiefmütterlich untersucht worden. Dieses Paper beschäftigt sich mit den bisherigen Auseinandersetzungen zum Thema der baulich-räumlichen Auswirkungen der Digitalisierung auf die Europäische Stadt. In einer Querschau wird der Stand der Forschung analysiert. So werden neben konkreten Forschungslücken auch Hinweise auf mögliche Untersuchungsparameter und -methoden herausgearbeitet, um im weiteren Vorgehen selbstständig kausale Bezüge zwischen Digitalisierung und Stadtraumentwicklung aufzeigen zu können

Do viruses use vectors to penetrate mucus barriers?

I propose a mechanism by which viruses successfully infect new individuals, despite being immotile particles with no ability for directed movement. Within cells, viral particle movements are directed by motors and elements of the cytoskeleton, but how viruses cross extracellular barriers, like mucus, remains a mystery. I propose that viruses cross these barriers by hitch-hiking on bacteria or sperm cells which can transport themselves across mucosal layers designed to protect the underlying cells from pathogen attack. An important implication of this hypothesis is that agents that block interactions between viruses and bacteria or sperm may be new tools for disease prevention.National Institute of Mental Health (U.S.) (grant P50 GM068763-06

Louisiana Resident Perceptions on Invasive Aquatic Plant Species and Their Management

Determining the public perception of invasive species in Louisiana is an important tool to help shape and develop future management decisions, educational material and ultimately public policy. Therefore, the primary purpose of this study was to determine the perceptions of adult Louisiana residents regarding invasive aquatic plant species and their management. An online survey was used to collect data on registered Louisiana residential boaters’ perceptions towards invasive aquatic plants and their management. A postcard with a quick response code leading to the survey was mailed to 6,000 randomly selected Louisiana registered residential boaters. Of the 230 Louisiana registered boaters that participated in the study, the largest group of respondents was aged 60+. Most boaters did not belong to any environmental or conservation organizations, while most boaters participated in fishing or hunting. Salvinia (giant and common) was the plant identified most frequently by boaters. The “Louisiana Department of Wildlife and Fisheries Website” was ranked as the most effective information source on invasive aquatic plant species by the largest number of respondents. Older boaters in Louisiana (60+) tended to have higher perceptions regarding the need for management of invasive aquatic plants. Registered boaters who were members of one or more environmental or conservation organizations had higher need for management perception scores as compared to boaters who were not a member. Invasive aquatic plants were reported as problematic for the majority of boaters while boating in Louisiana’s waterways. Boaters considered the problem with invasive aquatic plants in Louisiana “Very Serious.” The researcher recommends a follow-up study in Louisiana be designed to study the behaviors of boaters related to invasive aquatic plants and attempt to measure boaters’ intentions to prevent the future spread of these invaders in Louisiana

Biological hydrogels as selective diffusion barriers

The controlled exchange of molecules between organelles, cells, or organisms and their environment is crucial for life. Biological gels such as mucus, the extracellular matrix (ECM), and the biopolymer barrier within the nuclear pore are well suited to achieve such a selective exchange, allowing passage of particular molecules while rejecting many others. Although hydrogel-based filters are integral parts of biology, clear concepts of how their barrier function is controlled at a microscopic level are still missing. We summarize here our current understanding of how selective filtering is established by different biopolymer-based hydrogels. We ask if the modulation of microscopic particle transport in biological hydrogels is based on a generic filtering principle which employs biochemical/biophysical interactions with the filtered molecules rather than size-exclusion effects.National Institutes of Health (U.S.) (Grant P50GM068763)MIT Start-up FundsGerman Academic Exchange Service (Postdoctoral Fellowship

The permeability barrier of nuclear pore complexes appears to operate via hydrophobic exclusion

Nuclear pore complexes (NPCs) restrict the nucleocytoplasmic flux of most macromolecules, but permit facilitated passage of nuclear transport receptors and their cargo complexes. We found that a simple hydrophobic interaction column can mimic the selectivity of NPCs surprisingly well and that nuclear transport receptors appear to be the most hydrophobic soluble proteins. This suggests that surface hydrophobicity represents a major sorting criterion of NPCs. The rate of NPC passage of cargo–receptor complexes is, however, not dominated just by properties of the receptors. We found that large cargo domains drastically hinder NPC passage and require more than one receptor molecule for rapid translocation. This argues against a rigid translocation channel and instead suggests that NPC passage involves a partitioning of the entire translocating species into a hydrophobic phase, whereby the receptor:cargo ratio determines the solubility in that permeability barrier. Finally, we show that interfering with hydrophobic interactions causes a reversible collapse of the permeability barrier of NPCs, which is consistent with the assumption that the barrier is formed by phenylalanine-rich nucleoporin repeats that attract each other through hydrophobic interactions

Meiotic Spindle: Sculpted by Severing

Katanin is a conserved AAA ATPase with the ability to sever microtubules, but its biological function in animal cells has been obscure. A recent study using electron tomography has found that katanin stimulates the production of microtubules in the meiotic spindles of Caenorhabditis elegans oocytes

Enhanced diffusion by binding to the crosslinks of a polymer gel

Creating a selective gel that filters particles based on their interactions is a major goal of nanotechnology, with far-reaching implications from drug delivery to controlling assembly pathways. However, this is particularly difficult when the particles are larger than the gel’s characteristic mesh size because such particles cannot passively pass through the gel. Thus, filtering requires the interacting particles to transiently reorganize the gel’s internal structure. While significant advances, e.g., in DNA engineering, have enabled the design of nano-materials with programmable interactions, it is not clear what physical principles such a designer gel could exploit to achieve selective permeability. We present an equilibrium mechanism where crosslink binding dynamics are affected by interacting particles such that particle diffusion is enhanced. In addition to revealing specific design rules for manufacturing selective gels, our results have the potential to explain the origin of selective permeability in certain biological materials, including the nuclear pore complex.National Science Foundation (U.S.) (through Harvard Materials Research Science and Engineering Center Grant DMR-1420570)National Science Foundation (U.S.). Designing Materials to Revolutionize and engineer our Future (Grant DMR-123869)United States. Office of Naval Research (Grant N00014-17-1-3029)National Institutes of Health (U.S.). National Institute for Biomedical Imaging and Bioengineering (Grant R01 EB017755-04)National Science Foundation (U.S.). Career Award (PHY-1454673)National Science Foundation (U.S.). Materials Research Science and Engineering Centers (Program) (DMR-1419807

Charge as a Selection Criterion for Translocation through the Nuclear Pore Complex

Nuclear pore complexes (NPCs) are highly selective filters that control the exchange of material between nucleus and cytoplasm. The principles that govern selective filtering by NPCs are not fully understood. Previous studies find that cellular proteins capable of fast translocation through NPCs (transport receptors) are characterized by a high proportion of hydrophobic surface regions. Our analysis finds that transport receptors and their complexes are also highly negatively charged. Moreover, NPC components that constitute the permeability barrier are positively charged. We estimate that electrostatic interactions between a transport receptor and the NPC result in an energy gain of several kBT, which would enable significantly increased translocation rates of transport receptors relative to other cellular proteins. We suggest that negative charge is an essential criterion for selective passage through the NPC.Merck Research LaboratoriesNational Science Foundation (U.S.) (Division of Mathematical Sciences)Kavli Institute for Bionano Science & Technology at Harvard UniversityNational Centers for Systems Biology (U.S.) (NIGMS grant GM068763)National Institute of General Medical Sciences (U.S.

Informal modernism - spontaneous building in Mexico City

Die überall aufragenden Betonstützen der unfertigen Selbstbau-Häuser sind in Mexiko-Stadt zum Symbol des spontanen Bauens geworden. Gleichzeitig haben die chaotischen Hüttensiedlungen längst einem routinierten Selbsthilfe-Städtebau Platz gemacht, der das Wohnungsproblem informell, aber gut organisiert und im großen Stil angeht. So kann man auch von einer improvisierten oder "informellen Moderne" sprechen, die sich die Menschen überall dort geschaffen haben, wo die formelle Stadtplanung und Wohnungsversorgung versagt oder auf halbem Wege stecken geblieben ist.The looming concrete columns of unfinished self-help-houses in Mexico City have become a symbol of spontaneous building worldwide. At the same time, the chaotic clusters of miserable huts have long since made way for a routinized self help urbanism, which approaches the housing problem informally, yet well organized and on a large scale. Thus one may speak of an improvised or "informal modernism" that people have created everywhere, where formal city planning and housing has either failed or gotten stuck midway