69 research outputs found
Stadt-Land-Dualismus als Faktor erhöhter FlÀcheninanspruchnahme und angespannter WohnungsmÀrkte?
Die Betrachtung von der Stadt und dem Land als Gegensatzpaar, angespannte WohnungsmĂ€rkte in stĂ€dtisch geprĂ€gten RĂ€umen und erhöhte FlĂ€cheninanspruchnahme in stĂ€rker lĂ€ndlich geprĂ€gten RĂ€umen werden zumeist weitgehend unabhĂ€ngig voneinander diskutiert. Doch die sich reproduzierenden Stereotypen von âStadtâ und âLandâ beeinflussen nicht nur das bereitgestellte Angebot in lĂ€ndlichen RĂ€umen und haben damit einen direkten Zusammenhang zur Höhe der FlĂ€cheninanspruchnahme, sondern wirken auch in innerstĂ€dtische WohnungsmĂ€rkte und Segregationsprozesse hinein. Anhand von statistischen Daten sowie eigenen Erhebungen im Rahmen des Projektes Interko2 âIntegriertes WohnflĂ€chenkonzept in groĂstĂ€dtischen WachstumsrĂ€umenâ wird an der Region Leipzig-Westsachsen beispielhaft die Wirkungsweise dieses Stadt-Land-Dualismus dargelegt und eine regionale Denkweise als Alternative aufgezeigt
Carboxylate ion pairing with alkali-metal ions for ÎČ-Lactoglobulin and its role on aggregation and interfacial adsorption
We
report a combined experimental and computational study of the
whey protein ÎČ-lactoglobulin (BLG) in different electrolyte
solutions. Vibrational sum-frequency generation (SFG) and ellipsometry
were used to investigate the molecular structure of BLG modified airâwater
interfaces as a function of LiCl, NaCl, and KCl concentrations. Molecular
dynamics (MD) simulations and thermodynamic integration provided details
of the ion pairing of protein surface residues with alkali-metal cations.
Our results at pH 6.2 indicate that BLG at the airâwater interface
forms mono- and bilayers preferably at low and high ionic strength,
respectively. Results from SFG spectroscopy and ellipsometry are consistent
with intimate ion pairing of alkali-metal cations with aspartate and
glutamate carboxylates, which is shown to be more effective for smaller
cations (Li<sup>+</sup> and Na<sup>+</sup>). MD simulations show not
only carboxylateâalkali-metal ion pairs but also ion multiplets
with the alkali-metal ion in a bridging position between two or more
carboxylates. Consequently, alkali-metal cations can bridge carboxylates
not only within a monomer but also between monomers, thus providing
an important dimerization mechanism between hydrophilic surface patches
Bestandsaufnahme und alternative Konzeption der kommunalen Eigenentwicklung zur flÀcheneffizienten Steuerung der Siedlungsentwicklung: Das Beispiel der Region Halle-Leipzig
Die WohnflĂ€chenentwicklung im Rahmen der Siedlungsentwicklung ist ein maĂgeblicher Treiber der FlĂ€cheninanspruchnahme und somit entscheidend fĂŒr das Ziel, die Neuinanspruchnahme von FlĂ€che bis 2030 auf unter 30 Hektar pro Tag zu senken. Obwohl Raumplanung und Raumwissenschaft diesen Umstand seit Jahren adressieren, z. B. ĂŒber ein konsequentes FlĂ€chenmanagement, liegt die aktuelle FlĂ€chenneuinanspruchnahme in Deutschland bei rund 52 Hektar pro Tag (Stand 2019). Dies ist unter anderem darauf zurĂŒckzufĂŒhren, dass die Steuerung der Siedlungsentwicklung oftmals erst in Entwicklungen eingreift, die ĂŒber die den Gemeinden zustehende Eigenentwicklung hinausgehen. AnsĂ€tze zur Steuerung der Eigenentwicklung verbleiben meist auf einer pauschalen Ebene und befördern somit dezentrale Entscheidungen, die in der Summe die gesetzten Ziele konterkarieren. Ziel des Beitrags ist es, ein Modell zur Berechnung der Eigenentwicklung vorzustellen, welches nicht nur die demographische Entwicklung berĂŒcksichtigt, sondern die GröĂe der Eigenentwicklung an ortsspezifischen Bedarfen ausrichtet, um so den GrundsĂ€tzen der Raumordnung gerecht zu werden und eine nachhaltige Raumentwicklung zu ermöglichen. In seiner empirischen Basis stĂŒtzt sich der Beitrag auf Analysen von Daten der Statistischen LandesĂ€mter Sachsen und Sachsen-Anhalt sowie Befragungen, Interviews und Forschungsergebnisse, die im Rahmen des BMBF-geförderten Projektes Interko2 durchgefĂŒhrt wurden bzw. entstanden sind.The development of residential areas in the context of settlement development is a significant driver regarding land use and thus critical in achieving the goal of reduced new land use to less than 30 hectares per day by 2030. Although spatial planning and spatial science have been addressing this issue for years, e.g. through consistent land management, the current land use in Germany amounts to around 52 hectares per day (as of 2019). This is i.a. because the control of settlement development often only intervenes in developments that go beyond the own communal development. Approaches to controlling self-development usually remain on a blanket level and thus promote decentralized decisions that, in total, contradict the set goals. The aim of this paper is to present a model for calculating self-development, which not only takes demographic development into account, but also aligns the size of self-development with site-specific requirements to consider the principles of spatial planning and thus promote sustainable spatial development. In its empirical basis, the paper is based on statistical analyses of the respective needs as well as surveys, interviews research results that have been carried out or have arisen within the framework of the BMBFfunded project Interko2
pH effects on the molecular structure and charging state of b-Escin biosurfactants at the air-water interface
Saponins like b-escin exhibit an unusually high surface activity paired with a remarkable surface rheology which makes them as biosurfactants highly interesting for applications in soft matter colloids and at
interfaces. We have applied vibrational sum-frequency generation (SFG) to study b-escin adsorption layers at the air-water interface as a function of electrolyte pH and compare the results from SFG spectroscopy to complementary experiments that have addressed the surface tension and the surface
dilational rheology. SFG spectra of b-escin modified air-water interfaces demonstrate that the SFG intensity of OAH stretching vibrations from interfacial water molecules is a function of pH and dramatically
increases when the pH is increased from acidic to basic conditions and reaches a plateau at a solution
pH of > 6. These changes are attributable to the interfacial charging state and to the deprotonation of
the carboxylic acid group of b-escin. Thus, the change in OAH intensity provides qualitative information
on the degree of protonation of this group at the air-water interface. At pH < 4 the air-water interface is
dominated by the charge neutral form of b-escin, while at pH > 6 its carboxylic acid group is fully deprotonated and, consequently, the interface is highly charged. These observations are corroborated by the
change in equilibrium surface tension which is qualitatively similar to the change in OAH intensity as
seen in the SFG spectra. Further, once the surface layer is charge neutral, the surface elasticity drastically
increases. This can be attributed to a change in prevailing intermolecular interactions that change from dominating repulsive electrostatic interactions at high pH, to dominating attractive interactions, such as
hydrophobic and dispersive interactions, as well as, hydrogen bonding at low pH values. In addition to
the clear changes in OAH intensity from interfacial H2O, the SFG spectra exhibit drastic changes in the
CAH bands from interfacial b-escin which we relate to differences in the net molecular orientation.
This orientation change is driven by tighter packing of b-escin adsorption layers when the b-escin moiety
is in its charge neutral form (pH < 4).The authors gratefully acknowledge funding from the European
Research Council (ERC) under the European Unionâs Horizon 2020
research and innovation program (Grant Agreement 638278).Ye
Photo-Responsive Control of Adsorption and Structure Formation at the AirâWater Interface with Arylazopyrazoles
12. Folge (16.12.2020): The Podcast Before Christmas â Geographische Perspektiven auf Filme & Serien
In dieser nicht immer ganz ernst gemeinten Folge von SpacEconomics zum Jahresabschluss widmet sich Björn Braunschweig seiner scheinbar ganz ungeographischen Leidenschaft: Filmen und Serien. Dabei zeigt er, dass in manchen Filmen und Serien sogar ganz schön viel Geographie steckt und sie uns helfen können, geographische Konzepte und Theorien besser nachzuvollziehen. AuĂerdem spricht er darĂŒber wie Stereotypen unsere Bilder von Regionen prĂ€gen, was passiert, wenn Tatort-Kommissare auf dem Augustusplatz in Leipzig parken, welche Potenziale hydroponische Systeme fĂŒr die urbane Lebensmittelversorgung haben, warum Geographie eben keine LĂ€nderkunde ist, was um alles in der Welt der Porter'sche Diamant mit dem Mars zu tun hat, wie soziale Ungleichheit gemessen werden kann, warum eine "Schneeball Erde" mit -117 °C AuĂentemperatur nicht zwingend erstrebenswert ist und wie das VerhĂ€ltnis zwischen Zentrum und Peripherie die Gesellschaft beeinflussen kann
Role of imidazolium cations on the interfacial structure of roomâtemperature ionic liquids in contact with Pt(111) electrodes
Abstract Roomâtemperature ionic liquids (ILs) have gained considerable attention as an important addition to conventional electrolytes because they exhibit large electrochemical windows and can reduce existing overpotentials in electrocatalysis. For the interfacial electrochemistry of ILs, a comprehensive understanding of molecular ions and the resulting electric doubleâlayer structures as a function of electrode potential is mandatory, but the structures are largely different from conventional electrolytes. For that reason, we have studied the interfaces of Pt(111) in contact with ILs using 1âbutylâ3âmethylimidazolium [BMIM] and 1âbutylâ2,3âdimethylimidazolium [BMMIM] cations as well as bis(trifluoromethylsulfonyl)imide [NTf2] anions. We applied vibrational sumâfrequency generation (SFG), where we interrogate vibrational bands from interfacial cations, anions, as well as interfacial water in situ and under potential control. Structuring of [NTf2] anions and H2O with electrode potential show hysteresis while a strong Stark tuning was absent. This indicates that the IL ions are oriented in the vicinity of the interface, without being directly adsorbed to the Pt(111) surface. Using the CâH stretching band from CH groups at the imidazolium ring, the ring reorientation with electrode potential was qualitatively determined. The imidazolium ring reorients as a function of potential from a more parallel orientation to an upright orientation with respect to the interfacial plane. This leads to the formation of voids in the layered structure of ions at the interface, which can be then filled with H2O as evidenced by an increased SFG intensity from OâH stretching modes that are attributable to hydrogenâbonded interfacial water. Comparing the responses of the ILs, particularly of [BMMIM][NTf2], shows a compact structure and a significantly pronounced rearrangement of the imidazolium ring that can also facilitates better incorporation of H2O and significantly affects the reorientation of [NTf2] anions and, thus, causes a pronounced hysteresis with electrode potential
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