Charge inversion in DNA-amphiphile complexes: Possible application to gene therapy

We study a complex formation between the DNA and cationic amphiphilic molecules. As the amphiphile is added to the solution containing DNA, a cooperative binding of surfactants to the DNA molecules is found. This binding transition occurs at specific density of amphiphile, which is strongly dependent on the concentration of the salt and on the hydrophobicity of the surfactant molecules. We find that for amphiphiles which are sufficiently hydrophobic, a charge neutralization, or even charge inversion of the complex is possible. This is of particular importance in applications to gene therapy, for which the functional delivery of specific base sequence into living cells remains an outstanding problem. The charge inversion could, in principle, allow the DNA-surfactant complexes to approach negatively charged cell membranes permitting the transfection to take place.Comment: Latex, 5 figure

From bricks-and-mortar to bricks-and-clicks: logistics networks in omni-channel grocery retailing

Purpose: The advent of grocery sales through online channels necessitates that bricks-and-mortar retailers redefine their logistics networks if they want to compete online. Because the general understanding of such bricks-and-clicks logistics systems for grocery is still limited, the purpose of this paper is to analyze the internal logistics networks used to serve customers across channels by means of an exploratory study with retailers from different contexts. Design/methodology/approach: A total of twelve case companies from six European countries participated in this exploratory study. Face-to-face interviews with managers were the primary source for data collection. The heterogeneity of our sample enabled us to build a common understanding of logistics networks in grocery retailing on multiple channels and to understand the advantages of different warehousing, picking, internal transportation and last-mile delivery systems. Findings: Bricks-and-mortar grocery retailers are leveraging their existing logistics structures to fulfill online orders. Logistics networks are mostly determined by the question of where to split case packs into customer units. In non-food logistics channel integration is mostly seen as beneficial, but in grocery retailing this depends heavily on product, market and retailer specifics. The data from our heterogeneous sample reveals six distinct types for cross-channel order fulfillment. Practical implications: Our qualitative analysis of different design options can serve as decision support for retailers developing logistics networks to serve customers across channels. Originality/value: The paper shows the internal and external factors that drive the decisionmaking for omni-channel logistics networks for previously store-based grocery retailers. Thereby it makes a step towards building a contingency and configuration theory of retail networks design. It discusses in particular the differences between grocery and non-food omni-channel retailing, lastmile delivery systems and market characteristics in the decision-making of retail networks design

Empirical investigation of global wildfire drivers and development of a new flammability parametrisation for the INFERNO fire model

Wildfires have a significant impact on the Earth’s vegetation, atmospheric composition, and climate. There is also growing evidence that fire behaviour has already been altered in response to climate change. Given the anticipated increase in climate conditions conducive to wildfires in many regions of the world, there is an urgent need to advance our understanding of the drivers of wildfires and improve their representation in global Earth system models. Recognising and predicting such responses to climate change and the associated feedbacks is one of the key challenges of the field, and integrated vegetation–fire models have the potential to accomplish this goal. However, the relationship between wildfire activity and past vegetation productivity is still unclear. It has been hypothesised that this strongly contributes to the poor performance of state-of-the-art fire models in representing observed vegetation–fire relationships. Thus, this thesis examines the role of seasonal and long-term vegetation dynamics (and fuel accumulation dynamics) that are of fundamental importance for global wildfires due to their impact on fuel availability during the fire season. In addition to instantaneous climatic conditions, the seasonality of antecedent vegetation and climate conditions controlling fuel build-up and fuel drying was found to be important for the prediction of burnt area in an empirical analysis of wildfire drivers. These were then used to modify the vegetation parametrisation of the INFERNO fire model. By using sigmoidal relationships to explicitly consider antecedent vegetation and climate conditions, global performance was improved. Finally, the new model was evaluated using sensitivity analyses, demonstrating the overarching importance of dryness and temperature while also disentangling the different impacts model parameters have on the magnitude and phase performance of the new parametrisation.Open Acces

Atomic-scale measurement of ultraslow Li motions in glassy LiAlSi2 O6 by two-time L6 i spin-alignment echo NMR correlation spectroscopy

6Li spin-alignment echo (SAE) nuclear-magnetic-resonance (NMR) spectroscopy is used to monitor single-particle two-time correlation functions in LiAlSi2O6 glass. The method, here applied in the temperature range from 300 to 400 K, is sensitive to ultraslow Li hopping processes with rates (1/τSAE) down to 10 jumps/s. The use of a sample with natural 6Li abundance allowed the measurement of pure NMR spin-alignment echoes which are damped with increasing mixing time exclusively by slow Li jumps, i.e., free of influences arising from, e.g., interfering spin-diffusion effects. The considerably stretched correlation functions reveal the presence of a broad distribution of jump rates. The results are comprehensively compared with those recently obtained from both 7Li SAE and 7Li spin-lattice relaxation NMR as well as from dc conductivity measurements. Interestingly, the activation energy of the latter, which are sensitive to long-range Li transport parameters, is in good agreement with that microscopically probed by 6Li SAE NMR, here. © 2008 The American Physical Society

Blue City Mannheim Innovative Konzepte für Konversionsflächen in Mannheim

Im Rahmen der Konversion von 510 ha US-Militärflächen entsteht für die Stadt Mannheim die Chance Zukunftsthemen der Stadtentwicklung intensiv aufzugreifen. Stadterneuerung, Energieeffizienz, Infrastruktur und Mobilität sowie Innovationen und Entfaltungsmöglichkeiten heimischer Unternehmen stehen hierbei gleichermaßen im Fokus. Zur Entwicklung innovativer Ansätze wurde die AG Ingenieursmeile gebildet, in der Themen wie Neue Mobilität, Elektromobilität und Smart Grids herausgearbeitet wurden. Für die Weiterentwicklung und Integration dieser Ansätze hat der Fachbereich Wirtschafts- und Strukturförderung der Stadt Mannheim das themenübergreifende Konzept von MVV Enamic Regioplan erarbeiten lassen. Der Schwerpunkt des Konzeptes „Blue City Mannheim“ liegt auf der Ableitung konkreter Maßnahmen, die in den nächsten Jahren schrittweise umgesetzt werden sollen. Ein wesentliches Ziel ist die Reduktion der CO2-Emissionen im Verkehrssektor durch den Einsatz emissionsarmer (Elektro-) Fahrzeuge und die Umgestaltung des Modal Split. Die Maßnahmen wurden mit den strategischen Zielen der Stadt Mannheim, der wirtschaftspolitischen Strategie und den Anforderungen der Klimaschutzkonzeption 2020 abgestimmt. Als Grundlage werden zunächst vier übergeordnete Maßnahmen definiert: • Vernetzung / Öffentlichkeitsarbeit, • Masterplan Ladeinfrastruktur, • Masterplan Green Logistik sowie • Masterplan blue_village_franklin. Hierauf bauen 21 Einzelmaßnahmen in den Bereichen Fahrzeuge / Fuhrparks, Logistik, Verlagerung Modal Split, Intelligente Netze, Ladeinfrastruktur und Wissenstransfer auf. Als Einzelmaßnahmen werden beispielsweise Einsatzbereiche für emissionsarme Fahrzeuge bei der Umstellung von Fuhrparks und Flotten aufgezeigt. Im Bereich Logistik steht der innerstädtischen Liefer- und Güterverkehr im Mittelpunkt. Maßnahmen betreffen hier z.B. die Umstellung von innerstädtischen Transportverkehren auf Elektrofahrzeuge. Ziel hierbei ist neben der Einsparung von CO2-Emissionen insbesondere auch eine Verkehrslärmreduzierung im Stadtgebiet. Für eine Umgestaltung des Modal Split wird die Verknüpfung von Motorisiertem Individualverkehr (MIV) und ÖPNV an attraktiven Umsteigestationen vorgesehen. Weitere Maßnahmenschwerpunkte liegen in den Bereichen Energieerzeugung, speicherung und -verteilung, durch welche die Umweltpotenziale der Elektromobilität erst vollständig aktiviert werden können. Eine Optimierung von Verbrauch und Erzeugung erfolgt durch Einsatz von IT-Lösungen in intelligenten Netzen (Smart Grids). Maßnahmen für den Ausbau von Ladeinfrastrukturen im gesamten Stadtgebiet sowie die Einrichtung von Multi-System-Tankstellen für unterschiedliche Antriebstechniken ergänzen das Gesamtkonzept. Für den Wissenstransfer und für die öffentliche Wahrnehmung sollen Fachtagungen und Kongresse zu Themen der Neuen Mobilität und der Energieeffizienz durchgeführt werden. Der Maßnahmenkatalog ist nicht abschließend und kann bei Bedarf um weitere Maßnahmen ergänzt werden. Als Akteure für die Umsetzung dieser Maßnahmen sind sowohl Fachbereiche und Betriebe der Stadt Mannheim als auch Mannheimer Unternehmen, Einzelhandel und Handwerk angesprochen. Weiterhin werden die Mannheimer Hochschulen ebenso wie Verbände, die Kammern bis hin zu Privatpersonen in die Umsetzung einbezogen

Li Ion diffusion in nanocrystalline and nanoglassy LiAISi2O 6 and LiBO2 - Structure dynamics relations in two glass forming compounds

In the present study the Li diffusivity in nanostructured samples of two glass forming model systems, spodumene (LiAlSi2O6) and lithium metaborate (LiBO2), was examined using 7Li nuclear magnetic resonance (NMR) spin-lattice relaxometry and dc conductivity measurements. The nanostructured samples were prepared by high-energy ball milling of the respective crystalline starting material on the one hand and the corresponding glass on the other hand. The diffusivity of the glass exceeds that of the crystalline sample for both systems. However, when the crystalline samples are mechanically treated by ball milling the diffusivity is enhanced. Nevertheless, the diffusivity of these nanocrystalline samples remains lower than that of the corresponding glass. Surprisingly, when the glassy samples are treated in the same way the diffusivity decreases. After sufficiently long milling times the diffusivity of these nanoglassy samples approaches that of the nanocrystalline samples. This convergence effect seems to be due to structural relaxation processes as is suggested by supplementary infrared spectroscopy and 27Al, 12B magic angle spinning NMR measurements. © by Oldenbourg Wissenschaftsverla

Single-crystal X-ray structure analysis of the superionic conductor Li10GeP2S12

Tetragonal Li10GeP2S12 (LGPS) is the best solid Li ion conductor known to date. So far, the structure of the electrolyte was only determined from powder diffraction and Rietveld refinement. Here, we present the first single-crystal structure analysis of the tetragonal LGPS structure. The reported structure is largely verified. However, an additional Li position is clearly identified which might have a significant impact on the Li ion dynamics. All Li positions are partially occupied - a prerequisite for Li superionic conductors - and form a network of interconnected Li diffusion pathways. Therefore, we suggest that Li diffusion in this record solid electrolyte is less anisotropic than previously claimed