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Culture-Led Urban Development vs. Capital-Led Colonization of Urban Space: Savamala—End of Story?
(2020)
The city quarter of Savamala, as an integral part of Belgrade, has had a very turbulent development path during the last two centuries. This path included several ups and downs, and culminated in tension over the last decade. Savamala fell into silent oblivion in the 20th century, but succeeded in re-emerging into the focus of the public and interest groups, mainly due to the cultural milieu that developed in this area at the beginning of the 21st century. The cultural vibes of the city quarter attracted various urban actors, who created a new image of Savamala. Eventually, cultural functions started to fade; however, after several years and through vague political decisions, Savamala became the part of the largest construction site in Belgrade, the Belgrade Waterfront. This article highlights the development of Savamala in the 2010s—from a forgotten city quarter to a rising cultural quarter and finally to the ’future centre of the city’. This analysis shows the participation of different stakeholders at different stages of development (their influence, power levels, and the mechanisms they used), as well as the footprints that urban development left in the quarter.
Hintergrund und Ziele
Bei Patienten mit Vorhofflimmern (VHF) ist die Schlaganfallrate um das Fünffache erhöht und ca. ein Drittel aller Schlaganfälle werden durch Vorhofflimmern verursacht [98]. Das Schlaganfallrisiko kann durch den Einsatz von oralen Antikoagulantien (OAK) dramatisch um etwa zwei Drittel gesenkt werden [42]. Eine gute Adhärenz bei der Einnahme der OAK ist dabei für den Therapieerfolg von entscheidender Bedeutung. Ziel dieser Pilotstudie ist es, den Einfluss von pharmazeutischer Betreuung auf die Adhärenz in Bezug auf die Einnahme direkter oraler Antikoagulantien in der Indikation VHF im klinischen Versorgungsalltag zu untersuchen.
Methoden (Patienten, Material und Untersuchungsmethoden)
Bei dieser Pilotstudie handelt es sich um eine offene, prospektive, quasi-experimentelle Interventionsstudie mit sequenziellem Kontrollgruppendesign, die in Zusammenarbeit der Neurologischen Klinik und der Apotheke des Universitätsklinikums Erlangen (UKER) durchgeführt wurde. Der Einschluss von Patienten erfolgte von Februar 2014 bis November 2015 auf der Stroke Unit des UKER. Die 19 Patienten der Interventionsgruppe (IG) wurden ein Jahr lang durch eine klinische Pharmazeutin betreut. Die Betreuung bestand aus mehreren individuellen Schulungsgesprächen mit den thematischen Schwerpunkten Erkrankung und Medikation. Die ersten Gespräche fanden während des stationären Aufenthaltes der Patienten statt und wurden anschließend im ambulanten Bereich fortgesetzt. Weitere 21 Patienten, die keine pharmazeutische Betreuung erhielten, dienten als Kontrollgruppe (KG). Hauptfragestellung dieser Pilotstudie war, ob die Dosing Adherence bei Patienten der IG im Vergleich zu Patienten der KG zwölf Monate nach Entlassung aus der stationären Behandlung signifikant verbessert werden konnte. Die Messung der Adhärenz erfolgte in beiden Gruppen mittels MEMS® (Medication Event Monitoring System). Als sekundäre Endpunkte wurden weitere Adhärenz-Parameter (Taking Adherence, Timing Adherence, Drug Holidays, Pill Count, Adhärenz nach Morisky, Selbsteinschätzung) und verschiedene andere Variablen (Patientenwissen, gesundheitsbezogene Lebensqualität, arzneimittelbezogene Probleme, erneute Schlaganfallereignisse, Patientenzufriedenheit) erfasst und ausgewertet. Zum Nachweis signifikanter Unterschiede wurde für den primären Zielparameter ein Wilcoxon Rangsummen-Test für unverbundene Stichproben durchgeführt. Das Signifikanzniveau betrug 5% (p < 0,05), die statistische Power der Studie war 80%.
Ergebnisse und Beobachtungen
Innerhalb des zweiundzwanzigmonatigen Rekrutierungszeitraums erfüllten 109 Patienten die Einschlusskriterien, von denen 106 Patienten (97%) über eine Studienteilnahme aufgeklärt werden konnten. Hiervon gaben 47 Patienten (44%) ihr schriftliches Einverständnis zur Studienteilnahme. Während des einjährigen Studienzeitraums brachen 7 Patienten (15%) die Teilnahme vorzeitig ab, so dass am Ende insgesamt 40 Patienten ausgewertet werden konnten.
Die mittlere Dosing Adherence der Interventionsgruppe erreichte nach einem Jahr mit 93,75% einen signifikant höheren Wert als die DA in der Kontrollgruppe, die bei 73,84% (p=0,028) lag. Bei den sekundären Zielparametern Taking Adherence, Timing Adherence, Drug Holidays und Pill Count konnten durch die pharmazeutische Betreuung ebenfalls bessere Ergebnisse in der IG im Vergleich zur KG erreicht werden. Bei der Auswertung des Wissens der Patienten zu Erkrankung und Medikation lag die durchschnittliche Punktzahl in der IG höher als die in der KG, der Unterschied war jedoch statistisch nicht signifikant (p=0,079). Die gesundheitsbezogene Lebensqualität in der Interventionsgruppe war in den Subskalen Vitalität, emotionale Rollenfunktion und psychisches Wohlbefinden signifikant besser im Vergleich zur Kontrollgruppe. Während des Studienzeitraums wurden 21 arzneimittelbezogene Probleme (ABP) in der IG identifiziert, was im Durchschnitt ein ABP pro Patient bedeutete. Die Zufriedenheit mit der pharmazeutischen Betreuung war insgesamt sehr hoch.
Praktische Schlussfolgerungen
Das Konzept der pharmazeutischen Betreuung erwies sich als geeignet, die Adhärenz von Schlaganfallpatienten mit Vorhofflimmern in Bezug auf die orale Antikoagulation zu verbessern und somit einen wichtigen Beitrag zu einer erfolgreichen Therapie zu leisten. Daher ist es sinnvoll, diese Patienten interdisziplinär zu betreuen, um auch in Zukunft die Patienten optimal versorgen und in der Therapie unterstützen zu können. Die interdisziplinäre Zusammenarbeit wurde auch von Seiten der Patienten subjektiv als positiv empfunden und weiterhin gewünscht.
The experimental and numerical work reported here is rooted in ultrafast
molecular phenomena and nonlinear fiber optics, which are brought together in a deceptively simple system: a homo-nuclear molecular gas (e.g. H2,D2) loaded in the hollow-core of a broad-band guiding photonic crystal fiber (PCF) and exposed to ultrashort pulses of moderate energies (∼ μJ). On one hand, the
choice of a molecular gas as the nonlinear medium provides a rich playground
for light-matter interactions. This is because molecules exhibit a coherent and highly non-instantaneous response, associated with their roto-vibrational Raman
transitions. This differentiate their response from mono-atomic gases. On
the other hand, gas-filled PCF offers exquisite control of the gas-light interaction
with a tunable dispersion profile, extended interaction lengths at high intensity and a high-damage threshold. These characteristics, together with the weak and
anomalous dispersion, give access to a novel nonlinear dynamics such as solitons,
soliton self-compression, supercontinuum generation and dispersive wave
emission.
Molecular roto-vibrational transitions can be efficiently excited via two-photon inelastic scattering processes, such as coherent Raman scattering, leading to a fast and strong modulation of the gas refractive index, that for light molecular
species is characterized by an oscillation period ranging from a few to tens of femtoseconds and lasting over a period of hundreds of picoseconds at a few bars of pressure. As the driving source for these coherent material excitations I
used a single ultrashort pulse centered in the near infrared and self-compressing in time along the fiber position. In this way I demonstrated the excitation of rotational,
vibrational and rovibrational Raman transitions in hydrogen, characterized
by the fastest pure vibrational period in nature (8 fs). By exploring the
back-action of these fast refractive index modulations, I demonstrated for the first time the generation, and the guidance of a supercontinuum covering the whole spectral region from the vacuum ultraviolet (≃ 125 nm) to near-infrared
(1200 nm). The underlying supercontinuum nonlinear dynamics show several
novel albeit complex phenomena, which I investigated through a few different experiments, and theoretically by developing a new numerical and theoretical model. This ultrafast VUV source based on hollow-core PCF is potentially very
interesting for a large variety of applications. Here, I report the result of a collaborative work, where it was applied to photoemission spectroscopy of a topological
insulator sample.
Furthermore, the long-living nature of the Raman driven refractive index modulations
opens up a channel to control the nonlinear dynamics of any delayed
radiation as the self-compression of a delayed ultrashort pulse as well as the emission of dispersive wave in the UV region, as demonstrated experimentally
and numerically in this work.
To enable graphene oxide (GO) flakes for application based on solution processable technology, we show that they can be self-assembled from solution on flexible substrate driven by a Coulomb interaction with the self-assembled monolayer (SAM). Field-effect transistors exhibit a high hole mobility around 14 cm2/V·s after a reduction process from GO to reduced GO (rGO), and meanwhile the device resistance shows a linear scaling behavior with the channel length. Due to the flexibility of the SAM, the device parameters maintain stable, while different strains are applied to the substrate. This approach makes the combination of rGO and SAM suitable for low-cost flexible applications.
The scope of this work was to extend simple porphyrin-fullerene derivatives in three ways in order to mimic the primary events in natural photosynthesis. Such a compound is a [60]fullerene monoadduct, linked by a methyl malonyl group and an ethylene spacer to a zinc tetraphenylporphyrin (ZnP), which is capable of light induced charge separation (ZnP-C60). The first objective was to extend the porphyrin part compared to the single porphyrin dyads into a dendritic part, consisting of four porphyrins, namely, three zinc porphyrins and one free-base porphyrin. This enables the design and generation of a redox gradient, starting from the fullerene core (C60, the best acceptor) and spanning over the free-base porphyrin (H2P) and the zinc porphyrins (ZnP, the best donor) in the dendritic part (H2P-ZnP3). This redox gradient enables charge shift reactions along the gradient, which succeed the light induced charge separation. This results in an enhanced charge separation and sustains a long living charge separated state •+(ZnP3)-H2P-(C60)•-. It also is expected to lead to an increased light harvesting ability due to the accumulation of chromophores in one molecule and to the realization of an unidirectional energy gradient for purposeful energy transfer. The second objective was to extend the redox gradient by attaching ferrocene to the outermost porphyrins in order to separate generated charges over a greater distance in Fc9 ZnP3-H2P-C60 compared to ZnP3-H2P-C60. The third objective was to add NEWKOME-type dendrons to the dendritic porphyrin-fullerene derivatives and to subsequently deprotect the tert-butyl carboxylic ester groups safely in order to obtain pH-dependent water-soluble free carboxylic acid derivatives. The NEWKOME-type derivatives were deprotected employing a mild procedure to gain the free carboxylic acids. Thereby, the well-defined architecture with its energy and redox gradient was maintained. The usually applied acidic methods would have lead to migration of Zn(II) between ZnP and H2P. However, water-solubility of the NEWKOME-type derivatives was not observed. Nearly all of the flexible compounds, that means the porphyrins, the dyads, the dendritic porphyrins, the dendritic dyads, and the NEWKOME-type derivatives tend to exhibit atropisomerism and aggregation phenomena to a certain extent. The stereoisomers are probably stabilized by coordination of donor regions, for example, OH or OR groups, to the zinc centers (ZnP) and by interactions of the π-systems (porphyrins, C60). The atropisomers were assigned to the corresponding NMR signals as far as possible. Important, representative compounds (ZnP3-H2P-C60, Fc9 ZnP3-H2P-C60) and all building blocks corresponding to these systems were thoroughly electrochemically and photophysically probed in cooperation with the GULDI group. The UV/Vis and the redox properties of the higher compounds can be roughly described as the sum of the properties of their building blocks. The fluorescence experiments indicate the unidirectional energy transfer from the excited zinc porphyrins to the free-base porphyrins. Quantitative fluorescence quenching in the fullerene derivatives points at charge separation between the porphyrins and C60. This was ascertained by spectroscopic evidence of the radical cations (H2P)•+ and (ZnP)•+ as well as the radical anion (C60)•- observed in nano- and femtosecond flash photolysis experiments. The compounds ZnP3 H2P C60 and Fc9-ZnP3 H2P C60 were found to mimic the basic steps in natural photosynthesis, that is, light harvesting, unidirectional energy transfer, charge separation, and charge shift reactions. The systems were tested in organic solvents of different polarity (toluene, THF, and benzonitrile), in an agar matrix, and in highly viscous pure Triton X 100. A key factor is the lifetime of the charge separated states, for example, of •+(ZnP3) H2P (C60)•-. Compared to a lifetime as short as 100 ps in benzonitrile, long lifetimes of 100 ns in agar and even 460 ns in Triton X 100 were observed due to more linear conformations of the flexible compound ZnP3 H2P C60 in these highly viscous environments (agar, Triton X-100). It was found that the attached ferrocene (Fc9-ZnP3 H2P C60) did not take part in the charge shift reactions due to prior charge recombination. This “short circuit” could be prevent by substitution of the flexible ethylene spacers with a rigid alternative. In summary, it was shown that it is possible to mimic natural photosynthetic key processes using dendritic porphyrin-[60]fullerene hybrids. The influence of the environment was demonstrated. A fixed distance and a locked orientation of the chromophores, donors, and acceptors towards each other was found important. Therefore, rigid spacer could be used. This may be, for example, amide or alkyne units. Also, voluminous dendrons, e.g., higher generation NEWKOME-type dendrons or polyethylene glycol (PEG) polyethers, should be applied for effortless water-solubility.
Die Amran Gruppe in Südarabien besteht aus Karbonaten des Oberjura die im Oxford bis Tithon sedimentiert wurden. Die Arbeit beschreibt die Faziesarchitektur der Amran Gruppe in der Marib Provinz im Jemen. Sie enthält mikrofazielle Analysen, die mit mineralogischen und geochemischen Daten, sowie stabilen Isotopen erweitert sind. Die Resultate zeigen, dass die Amran Gruppe in einem flachen Schelfmeer am Gondwanas gebildet wurde. Biostratigrapisch kann der Zeitraum vom oberen Oxfordium bis in das untere Tithon nachgewiesen werden. Während des Oberjura gab es im Untersuchungsgebiet zwei Meeresspiegelhöchststände, die sich in der Faziesarchitektur der Amrangruppe widerspiegeln. Ein abschließender überregionaler Vergleich mit Formationen in Südarabien und am Horn von Afrika zeigt, dass sowohl fazielle, als auch lithostratigraphische Unterschiede bestehen, die die Existenz von mehreren Sedimentationsbecken am Ostrand Gondwanas belegen.
A novel finite element method for the 3d simulation of (many) particles in a Newtonian carrier liquid is presented. The method features the celebrated one domain approach to simplify the spatial discretization, a newly developed subspace projection method to account for the rigid body motion within the particles and an operator splitting to decouple the nonlinearities. Combined with local mesh refinement the method results in a fast and accurate algorithm which is, in addition conceptually simple to implement. Validation is achieved using the sedimentation of a single particle and comparing the resulting drag coefficient with theoretical and experimental results. Furthermore, a viscometer is considered where the effective viscosity of a particle laden fluid is compared with analytic results. Furthermore, a method for the solution of the Nernst–Planck–Poisson equations is presented. These equations describe the distribution of the concentration of charged substances in a fluid. Validation is carried out by stationary solutions of the equations. Finally, both methods are combined for the simulation of particulate electrodynamic flows.
Background Abiotic stress causes disturbances in the cellular homeostasis. Re-adjustment of balance in carbon, nitrogen and phosphorus metabolism therefore plays a central role in stress adaptation. However, it is currently unknown which parts of the primary cell metabolism follow common patterns under different stress conditions and which represent specific responses. Results To address these questions, changes in transcriptome, metabolome and ionome were analyzed in maize source leaves from plants suffering low temperature, low nitrogen (N) and low phosphorus (P) stress. The selection of maize as study object provided data directly from an important crop species and the so far underexplored C4 metabolism. Growth retardation was comparable under all tested stress conditions. The only primary metabolic pathway responding similar to all stresses was nitrate assimilation, which was down-regulated. The largest group of commonly regulated transcripts followed the expression pattern: down under low temperature and low N, but up under low P. Several members of this transcript cluster could be connected to P metabolism and correlated negatively to different phosphate concentration in the leaf tissue. Accumulation of starch under low temperature and low N stress, but decrease in starch levels under low P conditions indicated that only low P treated leaves suffered carbon starvation. Conclusions Maize employs very different strategies to manage N and P metabolism under stress. While nitrate assimilation was regulated depending on demand by growth processes, phosphate concentrations changed depending on availability, thus building up reserves under excess conditions. Carbon and energy metabolism of the C4 maize leaves were particularly sensitive to P starvation.
During embryogenesis, the transcription factor, Sox10, drives the survival and differentiation of the melanocyte lineage. However, the role that Sox10 plays in postnatal melanocytes is not established. We show in vivo that melanocyte stem cells (McSCs) and more differentiated melanocytes express SOX10 but that McSCs remain undifferentiated. Sox10 knockout (Sox10fl; Tg(Tyr::CreER)) results in loss of both McSCs and differentiated melanocytes, while overexpression of Sox10 (Tg(DctSox10)) causes premature differentiation and loss of McSCs, leading to hair graying. This suggests that levels of SOX10 are key to normal McSC function and Sox10 must be downregulated for McSC establishment and maintenance. We examined whether the mechanism of Tg(DctSox10) hair graying is through increased expression of Mitf, a target of SOX10, by asking if haploinsufficiency for Mitf (Mitfvga9) can rescue hair graying in Tg(DctSox10) animals. Surprisingly, Mitfvga9 does not mitigate but exacerbates Tg(DctSox10) hair graying suggesting that MITF participates in the negative regulation of Sox10 in McSCs. These observations demonstrate that while SOX10 is necessary to maintain the postnatal melanocyte lineage it is simultaneously prevented from driving differentiation in the McSCs. This data illustrates how tissue-specific stem cells can arise from lineage-specified precursors through the regulation of the very transcription factors important in defining that lineage.
The myelination of axons is a crucial step during vertebrate central nervous system (CNS) development, allowing for rapid and energy efficient saltatory conduction of nerve impulses. Accordingly, the differentiation of oligodendrocytes, the myelinating cells of the CNS, and their expression of myelin genes are under tight transcriptional control. We previously identified a putative transcription factor, Myelin Regulatory Factor (Myrf), as being vital for CNS myelination. Myrf is required for the generation of CNS myelination during development and also for its maintenance in the adult. It has been controversial, however, whether Myrf directly regulates transcription, with reports of a transmembrane domain and lack of nuclear localization. Here we show that Myrf is a membrane-associated transcription factor that undergoes an activating proteolytic cleavage to separate its transmembrane domain-containing C-terminal region from a nuclear-targeted N-terminal region. Unexpectedly, this cleavage event occurs via a protein domain related to the autoproteolytic intramolecular chaperone domain of the bacteriophage tail spike proteins, the first time this domain has been found to play a role in eukaryotic proteins. Using ChIP-Seq we show that the N-terminal cleavage product directly binds the enhancer regions of oligodendrocyte-specific and myelin genes. This binding occurs via a defined DNA-binding consensus sequence and strongly promotes the expression of target genes. These findings identify Myrf as a novel example of a membrane-associated transcription factor and provide a direct molecular mechanism for its regulation of oligodendrocyte differentiation and CNS myelination.
Loud hydroacoustic sources, such as naval mid-frequency sonars or airguns for marine geophysical prospecting, have been increasingly criticized for their possible negative effects on marine mammals and were implicated in several whale stranding events. Competent authorities now regularly request the implementation of mitigation measures, including the shut-down of acoustic sources when marine mammals are sighted within a predefined exclusion zone. Commonly, ship-based marine mammal observers (MMOs) are employed to visually monitor this zone. This approach is personnel-intensive and not applicable during night time, even though most hydroacoustic activities run day and night. This study describes and evaluates an automatic, ship-based, thermographic whale detection system that continuously scans the ship’s environs for whale blows. Its performance is independent of daylight and exhibits an almost uniform, omnidirectional detection probability within a radius of 5 km. It outperforms alerted observers in terms of number of detected blows and ship-whale encounters. Our results demonstrate that thermal imaging can be used for reliable and continuous marine mammal protection.
The deep ocean is the largest and least known ecosystem on Earth. It hosts numerous pelagic organisms, most of which are able to emit light. Here we present a unique data set consisting of a 2.5-year long record of light emission by deep-sea pelagic organisms, measured from December 2007 to June 2010 at the ANTARES underwater neutrino telescope in the deep NW Mediterranean Sea, jointly with synchronous hydrological records. This is the longest continuous time-series of deep-sea bioluminescence ever recorded. Our record reveals several weeks long, seasonal bioluminescence blooms with light intensity up to two orders of magnitude higher than background values, which correlate to changes in the properties of deep waters. Such changes are triggered by the winter cooling and evaporation experienced by the upper ocean layer in the Gulf of Lion that leads to the formation and subsequent sinking of dense water through a process known as “open-sea convection”. It episodically renews the deep water of the study area and conveys fresh organic matter that fuels the deep ecosystems. Luminous bacteria most likely are the main contributors to the observed deep-sea bioluminescence blooms. Our observations demonstrate a consistent and rapid connection between deep open-sea convection and bathypelagic biological activity, as expressed by bioluminescence. In a setting where dense water formation events are likely to decline under global warming scenarios enhancing ocean stratification, in situ observatories become essential as environmental sentinels for the monitoring and understanding of deep-sea ecosystem shifts.
Environmental impacts of wind energy facilities increasingly cause concern, a central issue being bats and birds killed by rotor blades. Two approaches have been employed to assess collision rates: carcass searches and surveys of animals prone to collisions. Carcass searches can provide an estimate for the actual number of animals being killed but they offer little information on the relation between collision rates and, for example, weather parameters due to the time of death not being precisely known. In contrast, a density index of animals exposed to collision is sufficient to analyse the parameters influencing the collision rate. However, quantification of the collision rate from animal density indices (e.g. acoustic bat activity or bird migration traffic rates) remains difficult. We combine carcass search data with animal density indices in a mixture model to investigate collision rates. In a simulation study we show that the collision rates estimated by our model were at least as precise as conventional estimates based solely on carcass search data. Furthermore, if certain conditions are met, the model can be used to predict the collision rate from density indices alone, without data from carcass searches. This can reduce the time and effort required to estimate collision rates. We applied the model to bat carcass search data obtained at 30 wind turbines in 15 wind facilities in Germany. We used acoustic bat activity and wind speed as predictors for the collision rate. The model estimates correlated well with conventional estimators. Our model can be used to predict the average collision rate. It enables an analysis of the effect of parameters such as rotor diameter or turbine type on the collision rate. The model can also be used in turbine-specific curtailment algorithms that predict the collision rate and reduce this rate with a minimal loss of energy production.
Efficient self-consistent treatment of electron correlation within the random phase approximation
(2013)
A self-consistent Kohn-Sham (KS) method is presented that treats correlation on the basis of the adiabatic-connection dissipation-fluctuation theorem employing the direct random phase approximation (dRPA), i.e., taking into account only the Coulomb kernel while neglecting the exchange-correlation kernel in the calculation of the Kohn-Sham correlation energy and potential. The method, denoted self-consistent dRPA method, furthermore treats exactly the exchange energy and the local multiplicative KS exchange potential. It uses Gaussian basis sets, is reasonably efficient, exhibiting a scaling of the computational effort with the forth power of the system size, and thus is generally applicable to molecules. The resulting dRPA correlation potentials in contrast to common approximate correlation potentials are in good agreement with exact reference potentials. The negatives of the eigenvalues of the highest occupied molecular orbitals are found to be in good agreement with experimental ionization potentials. Total energies from self-consistent dRPA calculations, as expected, are even poorer than non-self-consistent dRPA total energies and dRPA reaction and non-covalent binding energies do not significantly benefit from self-consistency. On the other hand, energies obtained with a recently introduced adiabatic-connection dissipation-fluctuation approach (EXXRPA+, exact-exchange random phase approximation) that takes into account, besides the Coulomb kernel, also the exact frequency-dependent exchange kernel are significantly improved if evaluated with orbitals obtained from a self-consistent dRPA calculation instead of an exact exchange-only calculation. Total energies, reaction energies, and noncovalent binding energies obtained in this way are of the same quality as those of high-level quantum chemistry methods, like the coupled cluster singles doubles method which is computationally more demanding.
The concept of entropy and the correct application of the Second Law of thermodynamics are essential in order to understand the reason why quantum error correction (QEC) is thermodynamically possible and no violation of the Second Law occurs during its execution. We report here on our preliminary work aiming at an information-theoretic analysis extended to QEC in the presence of imperfections.
Solid State Nuclear Track Detectors of the CR-39/PM-355 type were irradiated with protons with energies in the range from 0.2 to 8.5 MeV. Their intensities and energies were controlled by a Si surface barrier detector located in an accelerator scattering chamber. The ranges of protons with energies of 6–7 MeV were comparable to the thickness of the PM-355 track detectors. Latent tracks in the polymeric detectors were chemically etched under standard conditions to develop the tracks. Standard optical microscope and scanning electron microscopy techniques were used for surface morphology characterization.
The interaction between zinc-tetraphenylporphyrin (ZnTPP) and fullerenes (C60 and C60F48) are studied using ultraviolet photoelectron spectroscopy (UPS) and scanning tunneling microscopy (STM). Low temperature STM reveals highly ordered ZnTPP monolayers on Au(111). In contrast to C60, a submonolayer coverage of C60F48 results in long-range disorder of the underlying single ZnTPP layer and distortion of individual ZnTPP molecules. This is induced by substantial charge transfer at the organic-organic interface, revealed by the interface energetics from UPS. However, a second layer of ZnTPP prevents C60F48 guests from breaking the self-assembled porphyrin template. This finding is important for understanding the growth behaviour of “bottom-up” functional nanostructures involving strong donor-acceptor heterojunctions in molecular electronics.
A new method based on an extension of ring-polymer molecular dynamics is proposed for the calculation of thermal correlation functions in electronically nonadiabatic systems. The ring-polymer dynamics are performed using a continuous-variable representation of the electronic states within the mapping approach, such that the electronic and nuclear degrees of freedom are treated on an equal footing. Illustrative applications of the method show good agreement with exact quantum results for the dynamics over short to moderate times and reveal a systematic improvement over the classical implementation of the mapping approach (single-bead limit). Being based on trajectories, the method scales well with the number of degrees of freedom and will be applicable to simulate certain nonadiabatic processes in complex molecular systems.
We demonstrate that by means of a local top-gate current oscillations can be observed in extended, monolayered films assembled from monodisperse metal nanocrystals—realizing transistor function. The oscillations in this metal-based system are due to the occurrence of a Coulomb energy gap in the nanocrystals which is tunable via the nanocrystal size. The nanocrystal assembly by the Langmuir-Blodgett method yields homogeneous monolayered films over vast areas. The dielectric oxide layer protects the metal nanocrystal field-effect transistors from oxidation and leads to stable function for months. The transistor function can be reached due to the high monodispersity of the nanocrystals and the high super-crystallinity of the assembled films. Due to the fact that the film consists of only one monolayer of nanocrystals and all nanocrystals are simultaneously in the state of Coulomb blockade the energy levels can be influenced efficiently (limited screening).