Development of an Autonomous Mammalian \u3ci\u3elux\u3c/i\u3e Reporter System

Since its characterization, the definitive shortcoming of the bacterial luciferase (lux) bioluminescent reporter system has been its inability to express at a functional level in the eukaryotic cellular background. While recent developments have allowed for lux function in the lower eukaryote Saccharomyces cerevisiae, they have not provided for autonomous function in higher eukaryotes capable of serving as human biomedical proxies. Here it is reported for the first time that, through a process of poly-bicistronic expression of human codon-optimized lux genes, it is possible to autonomously produce a bioluminescent signal directly from mammalian cells. The low background of the bioluminescent signal, along with its characteristic lack of substrate amendment required for bioluminescent production, makes a mammalian-based lux reporter system ideal for real-time monitoring of cell culture or murine model systems. The delectability of a lux-based system provides for a functionally equivalent process to monitoring firefly luciferase-expressing cells under cell culture or subcutaneous imaging conditions without the well-documented uncertainties stemming from additional substrate introduction. However, the relatively blue-shifted emission wavelength of the lux reporter system, along with its low quantum yield, has been shown to reduce its effectiveness for use during deep tissue imaging of animal subjects. Despite these disadvantages, it has been demonstrated that a human cell line expressing the human codon-optimized lux genes can function as a biosensor for determination of human bioavailability of toxic compounds and that, by regulating the production of the luxC and luxE genes, the lux system can be employed as the first mammalian, real-time, fully autonomous bioreporter. These cell lines provide unique and efficient models for the detection and monitoring of human-relevant compounds of interest. The limiting reagent for bioluminescent production in the mammalian cellular background has been determined to be the cytosolic availability of the FMNH2 co-substrate and, in light of this evidence, directions for future optimization have been characterized and evaluated in respect to their ability to increase bioluminescent yield under these conditions

Why Hybrid Meson Coupling to Two S-wave Mesons is Suppressed

We introduce strong interaction selection rules for the two-body decay and production of hybrid and conventional mesons coupling to two S-wave hybrid or conventional mesons. The rules arise from symmetrization in states in the limit of non-relativistically moving quarks. The conditions under which hybrid coupling to S-wave states is suppressed are determined by the rules, and the nature of their breaking is indicated.Comment: 9 pages, LaTeX, 1 eps figures, uses epsf. Minor modifications, Title chang

New pathways to tungsten and molybdenum oxides, nitrides and azides

This research effort focused on the use of both inorganic solution syntheses of molecular precursors and solid state reactions involving molecular compounds to yield desired condensed materials. Two types of molecular compounds have been investigated. First, trichloronitridotungsten(VI) ((WNCl[subscript]3] [subscript]4) has been prepared using an improved synthetic approach and characterized structurally by single crystal X-ray diffraction techniques. (WNCl[subscript]3] [subscript]4 crystallizes in the space group P1 as planar 8-membered W-N rings interconnected through chloride bridges. The inter-tetramer linkage is weak and broken easily to accommodate basic ligands in the site trans to the W-N triple bond. The reactivity of WNCl[subscript]3, with nitriding agents, such as ammonia, ytrimethylsilylazide and lithium nitride, has been investigated, which resulted in the preparation and spectroscopic identification of new tungsten azido and nitrido compounds. Second, the reactivity of the metal dimers Mo[subscript]2(O[subscript]2CCH[subscript]3)[subscript]4 and Mo[subscript]2Cl[subscript]4py[subscript]4 with trimethylsilylazide has been explored, and the reactions in pyridine were found to yield a material corresponding to the formulation, MoN(N[subscript]3)py. Thermolytic decomposition of this azide at 280°C was performed under argon, dynamic vacuum or ammonia. The thermal decomposition in ammonia was found to produce a molybdenum nitride relatively free of carbon (5%, compared to 24% in materials decomposed in inert environments) with a Mo:N ratio of 1:1.8;Through the use of solid state reactions, WNCl[subscript]3 was converted into a hexagonal ammonium tungsten bronze, (NH[subscript]4)[subscript]0.28WO[subscript] 3-y(NH)[subscript] y. Relative to conventional preparations, this new ammonium bronze synthesis increased the probability of isoelectronic imido substitution for oxide in the bronze framework. Rietveld refinements of neutron powder data, for this bronze, indicated strongly that nitrogen, in the form of imide, does not substitute for oxygen (i.e., y = 0 in the previous formulation). A model for ammonium cation motion in the hexagonal channels for the bronze was developed. Electrical resistivity measurements on a pressed pellet of this hexagonal bronze show a temperature dependence like that of a low-band gap semiconductor, in contrast to conventionally prepared hexagonal bronze phases that are metallic conductors

Evaluation of valued youth: a national peer-tutoring programme to increase self confidence and motivation

Established first in the USA, Valued Youth has operated in the UK since 1996, and is currently implemented in about 50 schools in 8 regions. The programme is intended to help secondary school students who are at risk of disengaging with school or underperforming for a variety of reasons. These students are selected as tutors, given training on how to work with younger children and placed in a local primary school where they support pupils' learning. Valued Youth can be seen as one of many initiatives in secondary schools on re-engagement in learning and contributes to the UK government strategy of extending opportunities and providing flexible learning experiences to meet individual learners' needs and aptitudes. Evidence from the USA has shown the value of the programme in reducing drop-out, strengthening youngsters' perceptions of self and school, and reducing disciplinary referrals and absenteeism. The evaluation discussed in this paper considers the effect of the programme in a UK context, not only in terms of young people's attendance, attainment and confidence, but also in terms of what sort of youngsters seem to benefit and the effects of financial rewards, if any, on the outcomes. The paper reports on the first year of a two-year evaluation. Data were obtained from a pre- and post-questionnaire survey among tutors, a workshop with coordinators and visits to selected case study schools in several regions. Almost all tutors enjoyed the programme and would recommend the experience to others. There was a relatively low dropout and the programme was warmly appreciated by participating primary schools. We have evidence that Valued Youth markedly raises confidence, improves communication skills and keeps some at risk youngsters on track in school. Many types of youngsters benefit from the experience; those who lack confidence and have poor communication skills seem to make the most progress. Successful tutors tend to be those who are committed to the programme, willing to learn, are flexible and cooperative, and have some ability to interact with others, particularly children and primary teachers.</p

Two Photon Couplings of Hybrid Mesons

A new formalism is developed for the two photon production of hybrid mesons via intermediate hadronic decays. In an adiabatic and non-relativistic context with spin 1 pair creation we obtain the first absolute estimates of unmixed hybrid production strengths to be small (0.03 - 3 eV) in relation to experimental meson widths (0.1 - 5 keV). Within this context, two photon experiments at Babar, Cleo II, LEP2 and LHC therefore strongly discriminate between hybrid and conventional meson wave function components, filtering out conventional meson components. Decay widths of unmixed hybrids vanish. Conventional meson two photon widths are roughly in agreement with experiment.Comment: 15 pages, LaTeX, 2 postscript figures, uses epsf. Rewritten for clarificatio

Gyromagnetic Ratios of Bound Particles

A new approach to calculation of the binding corrections to the magnetic moments of the constituents in a loosely bound system, based on the Bargmann-Michel-Telegdi equation, is suggested. Binding corrections are calculated in this framework, and the results confirm earlier calculations performed by other methods. Our method clearly demonstrates independence of the binding corrections on the magnitude of the spin of the constituents.Comment: 10 pages, RevTe

Hadronic decays from the lattice

We discuss strategies to determine hadronic decay couplings from lattice studies. As an application, we explore the decay of a vector meson to two pseudoscalar mesons with $N_f=2$ flavours of sea quark. Although we are working with quark masses that do not allow a physical decay, we show how the transition rate can be evaluated from the amplitude for $\rho \to \pi \pi$ and from the annihilation component of $\pi \pi \to \pi \pi$. We explore the decay amplitude for two different pion momenta and find consistent results. The coupling strength we find is in agreement with experiment. We also find evidence for a shift in the $\rho$ mass caused by mixing with two pion states.Comment: Proc. Latt03 (spectrum), 3 pages, 4 fig

Implications of a J^PC exotic

Recent experimental data from BNL on the isovector J^PC =1^-+ exotic at 1.6 GeV in \rho\pi indicate the existence of a non-quarkonium state consistent with lattice gauge theory predictions. We discuss how further experiments can strengthen this conclusion. We show that the \rho\pi, \eta'\pi and \eta\pi couplings of this state qualitatively support the hypothesis that it is a hybrid meson, although other interpretations cannot be eliminated.Comment: 10 pages, LaTeX, minor numerical correction

Elements of Proximal Formative Assessment in Learners’ Discourse about Energy

Proximal formative assessment, the just-in-time elicitation of students\u27 ideas that informs ongoing instruction, is usually associated with the instructor in a formal classroom setting. However, the elicitation, assessment, and subsequent instruction that characterize proximal formative assessment are also seen in discourse among peers. We present a case in which secondary teachers in a professional development course at SPU are discussing energy flow in refrigerators. In this episode, a peer is invited to share her thinking (elicitation). Her idea that refrigerators move heat from a relatively cold compartment to a hotter environment is inappropriately judged as incorrect (assessment). The instruction (peer explanation) that follows is based on the second law of thermodynamics, and acts as corrective rather than collaborative