Triphilic ionic-liquid mixtures: fluorinated and non-fluorinated aprotic ionic-liquid mixtures

We present here the possibility of forming triphilic mixtures from alkyl- and fluoroalkylimidazolium ionic liquids, thus, macroscopically homogeneous mixtures for which instead of the often observed two domainspolar and nonpolarthree stable microphases are present: polar, lipophilic, and fluorous ones. The fluorinated side chains of the cations indeed self-associate and form domains that are segregated from those of the polar and alkyl domains. To enable miscibility, despite the generally preferred macroscopic separation between fluorous and alkyl moieties, the importance of strong hydrogen bonding is shown. As the long-range structure in the alkyl and fluoroalkyl domains is dependent on the composition of the liquid, we propose that the heterogeneous, triphilic structure can be easily tuned by the molar ratio of the components. We believe that further development may allow the design of switchable, smart liquids that change their properties in a predictable way according to their composition or even their environment

National Transonic Facility: A review of the operational plan

The proposed National Transonic Facility (NTF) operational plan is reviewed. The NTF will provide an aerodynamic test capability significantly exceeding that of other transonic regime wind tunnels now available. A limited number of academic research program that might use the NTF are suggested. It is concluded that the NTF operational plan is useful for management, technical, instrumentation, and model building techniques available in the specialized field of aerodynamic analysis and simulation. It is also suggested that NASA hold an annual conference to discuss wind tunnel research results and to report on developments that will further improve the utilization and cost effectiveness of the NTF and other wind tunnels

Fate of the Quasi-condensed State for Bias-driven Hard-Core Bosons in one Dimension

Bosons in one dimension display a phenomenon called quasi-condensation, where correlations decay in a powerlaw fashion. We study the fate of quasi-condensation in the non-equilibrium steady-state of a chain of hard-core bosons coupled to macroscopic leads which are held at different chemical potentials. It is found that a finite bias destroys the quasi-condensed state and the critical scaling function of the quasi-condensed fraction, near the zero bias transition, is determined. Associated critical exponents are determined and numerically verified. Away from equilibrium, the system exhibits exponentially decaying correlations that are characterized by a bias-dependent correlation length that diverges in equilibrium. In addition, power-law corrections are found, which are characterized by an exponent that depends on the chain-leads coupling and is non-analytic at zero bias. This exactly-solvable nonequilibrium strongly-interacting system has the remarkable property that, the near-equilibrium state at infinitesimal bias, cannot be obtained within linear response. These results aid in unraveling the intricate properties spawned by strong interactions once liberated from equilibrium constraints.Comment: 7 pages, 4 figure

All-reflective UV-VIS-NIR transmission and fluorescence spectrometer for mu m-sized samples

We report on an optical transmission spectrometer optimized for tiny samples. The setup is based on all-reflective parabolic optics and delivers broadband operation from 215 to 1030 nm. A fiber-coupled light source is used for illumination and a fiber-coupled miniature spectrometer for detection. The diameter of the probed area is less than 200 mu m for all wavelengths. We demonstrate the capability to record transmission, absorption, reflection, fluorescence and refractive indices of tiny and ultrathin sample flakes with this versatile device. The performance is validated with a solid state wavelength standard and with dye solutions

First steps towards smart drying of beef slices seasoned with different pre-treatments

In this study, beef slices seasoned with salt (S) and salt and vinegar (S+V) were dried at 60 °C in a convective drier and the development of moisture ratio (MR) and colour change (ΔE) was compared to blind samples (B). Hyperspectral imaging (HSI) was applied to create prediction models for moisture content and L, a* and b* values. Regression coefficients of >0.9 could be achieved related to each pre-treatment, but also for combined data of all the pre-treatments

Development of a thermal ionizer as ion catcher

An effective ion catcher is an important part of a radioactive beam facility that is based on in-flight production. The catcher stops fast radioactive products and emits them as singly charged slow ions. Current ion catchers are based on stopping in He and H$_2$ gas. However, with increasing intensity of the secondary beam the amount of ion-electron pairs created eventually prevents the electromagnetic extraction of the radioactive ions from the gas cell. In contrast, such limitations are not present in thermal ionizers used with the ISOL production technique. Therefore, at least for alkaline and alkaline earth elements, a thermal ionizer should then be preferred. An important use of the TRI$\mu$P facility will be for precision measurements using atom traps. Atom trapping is particularly possible for alkaline and alkaline earth isotopes. The facility can produce up to 10$^9$ s$^{-1}$ of various Na isotopes with the in-flight method. Therefore, we have built and tested a thermal ionizer. An overview of the operation, design, construction, and commissioning of the thermal ionizer for TRI$\mu$P will be presented along with first results for $^{20}$Na and $^{21}$Na.Comment: 10 pages, 4 figures, XVth International Conference on Electromagnetic Isotope Separators and Techniques Related to their Applications (EMIS 2007

De novo design of heat-repressible RNA thermosensors in E-coli

RNA-based temperature sensing is common in bacteria that live in fluctuating environments. Most naturally-occurring RNA thermosensors are heat-inducible, have long sequences, and function by sequestering the ribosome binding site in a hairpin structure at lower temperatures. Here, we demonstrate the de novo design of short, heat-repressible RNA thermosensors. These thermosensors contain a cleavage site for RNase E, an enzyme native to Escherichia coli and many other organisms, in the 5′ untranslated region of the target gene. At low temperatures, the cleavage site is sequestered in a stem–loop, and gene expression is unobstructed. At high temperatures, the stem–loop unfolds, allowing for mRNA degradation and turning off expression. We demonstrated that these thermosensors respond specifically to temperature and provided experimental support for the central role of RNase E in the mechanism. We also demonstrated the modularity of these RNA thermosensors by constructing a three-input composite circuit that utilizes transcriptional, post-transcriptional, and post-translational regulation. A thorough analysis of the 24 thermosensors allowed for the development of design guidelines for systematic construction of similar thermosensors in future applications. These short, modular RNA thermosensors can be applied to the construction of complex genetic circuits, facilitating rational reprogramming of cellular processes for synthetic biology applications