Dipole-switch induced modification of the emissive response of carbonnanotubes

The interaction of carbon nanotubes with the molecular dipole switch spiropyran is expected to affect the optical response of the tubes. Until now, the need of anchor groups to immobilize the switches on the tubes has hindered the experimental observation of the effects of switching on the emission behavior of the tubes. Here we present spiropyran-carbon nanotube complexes obtained by micelle swelling. This method does not require any anchor nor sophisticated chemistry to warrant close tube-switch proximity. For the first time, we observe the shifts predicted theoretically and their effect on the tubes' excitation and emission energies

Chiral selectivity of polyglycerol-based amphiphiles incorporating different aromatic cores

Customized polyglycerol-based surfactants incorporating different aromatic cores are used to isolate and suspend carbon nanotubes in water. Different cores yield suspension with distinct chiral species distribution. Increasing the number of the phenyl rings connecting head and tail, the dispersion of the semiconducting species becomes sharper toward the nanotubes with bigger family index

Carbon nanotube chirality enrichment through chirality-selective precipitation

The interaction with surfactants changes from one carbon nanotube species to the other. We used this to replace non-ionic surfactants by ionic ones. By fine-tuning the replacement conditions, we covered some specific nanotubes with non-ionic surfactants and the others with ionic ones. Addition of salt triggers precipitation of the species suspended by the ionic surfactant; this effectively leads to chiral selective enrichment of a carbon nanotube suspension. We hence produce an (8,4)-enriched suspension by replacing a polyglycerol-based custom amphiphile with the commercial SDBS and salting with NaCl

Relationship between kinetics of stover fermentation as described by the Hohenheim in vitro gas production test and voluntary feed intake of 54 cereal stovers

.54 Getreidearten aus Syrien (36 Gerstenstrohs), Aethiopien (8 Tefstrohs) und Grossbritannien (10 Weizen- und Gerstenstrohs, unbehandelt und NH3-behandelt) wurden in vivo (Schaf, Kalb) und in vitro untersucht. Eine Kombination von Gasvolumen zu fruehen Inkubationszeiten (4, 6 oder 8 Std.) mit dem Quotienten von wahrer Verdaulichkeit zu Gasvolumen nach 24 stuend. Inkubation erklaerten 81-83% der Varianz in der freiwilligen Futteraufnahme. Ernterueckstaende, die einen hoeheren Teil der wahr abbaubaren Substanz in mikrobieller Biomasse anlegen, zeigten eine hoehere Futteraufnahme als solche, die abbaubares Substrat bevorzugt in Fettsaeuren ueberfuehrenSIGLEAvailable from: Hohenheim Univ., D-70593 Stuttgart (Germany). Universitaetsbibliothek, Garbenstr. 15 / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman

Government Transparency in Decision Making

Freedom of information (FOI) regimes are a hallmark of modern democracies and a crucial element of any government transparency and integrity framework. This paper examines how government responses to COVID-19 brought the need for greater transparency of government decision making to the fore. Genuine engagement with FOI regimes provides a fundamental mechanism to keep government decision makers accountable and increases and maintains trust capital between citizens and the state. In turn, governments rely on this trust capital to take strong and decisive action—as highlighted by global responses to COVID19. The author argues that FOI is an important mechanism to challenge poor government decision making, and ultimately enhance the long-term health of our democracy.</jats:p

Government Transparency in Decision Making

Freedom of information (FOI) regimes are a hallmark of modern democracies and a crucial element of any government transparency and integrity framework. This paper examines how government responses to COVID-19 brought the need for greater transparency of government decision making to the fore. Genuine engagement with FOI regimes provides a fundamental mechanism to keep government decision makers accountable and increases and maintains trust capital between citizens and the state. In turn, governments rely on this trust capital to take strong and decisive action--as highlighted by global responses to COVID19. The author argues that FOI is an important mechanism to challenge poor government decision making, and ultimately enhance the long-term health of our democracy. Full text also available via Informit</a

Designing a spiropyran-based molecular switch for carbon nanotube functionalization: Influence of anchor groups and tube-switch separation

Molecular switch compounds, consisting of aromatic anchoring groups connected to a spiropyran moiety, are exploited for carbon nanotube functionalization. The effect of the different anchor groups on sample distribution and debundling efficiency is investigated as well as the influence of the anchor–switch distance and hence tube–switch separation. Morphologically similar anchor groups result in similar chiral compositions of the sample. With smaller separation, the tube–switch interaction strength increases as well as the lifetime of the ring opened isomer

Tuning the interaction between carbon nanotubes and dipole switches: the influence of the change of the nanotube-spiropyran distance

The non-covalent functionalization of carbon nanotubes with spiropyran molecules, serving as optically addressable dipole switches, is reported. Two kinds of pyrene–spiropyran-based dyads with spacers of different lengths resulting in different switch–tube distances were investigated. While both surfactants were able to form stable carbon nanotube suspensions, the different distances between the switch and the tube affected both of the components' optical properties. In the case of the shorter spacer, the nanotubes' luminescence as well as the merocyanine absorption band were red-shifted and furthermore, the rate of the merocyanine → spiropyran thermal back isomerization was decreased