Bioluminescent quantitation and detection of gene expression during infectious disease

By combining the advantages of RT-PCR with the sensitivity of bioluminescence using the photoprotein aequorin, a bioluminescence assay has been applied to the determination of message regulation during infectious disease. The bioluminescence produced by the aequorin conjugate covers more than seven logs concentration, of which approximately five logs produces a linear relationship between product and bioluminescence signal. Aequorin - based bioluminescent detection protocols for mRNA are sensitive into the attomolar range, which obligate fewer cycles of PCR and avoid the plateau effect traditionally associated with other noncompetitive RT-PCR techniques. Additional advantages of aequorin-based bioluminescence methods are ease of automation, compatibility with microtiter plate format, low cost, and flexibility.     

Nonexistence of Multiple-Instanton Solution of the Massless 4D ϕ4 Theory

The massless ϕ⁴ theory in four Euclidean dimensions is shown not to have a multiple-instanton solution — even though it does have a single-instanton solution. Our criterion for a multiple-instanton solution of this nontopological theory is that the energy-momentum tensor of the solution be identically zero. Arguments are given that a similar result holds in any number of dimensions for a one-component scale-invariant scalar theory.     

Classical CP N−1 crystal

Two-dimensional Euclidean CP ^N?1 ffields are conformal-transformed into fields with periodic spatial (crystal-like) structures, both at zero temperature and at finite temperature. Specific solutions of the crystal-like CP ^N?1 model are discussed     

Chemical potentials in gauge theories

One-loop calculations of the thermodynamic potential Ω are presented for temperature gauge and non-gauge theories. Prototypical formulae are derived which give Ω as a function of both (i) boson and/or fermion chemical potential, and in the case of gauge theories (ii) the thermal vacuum parameter A₀=const (A_μ is the euclidean gauge potential). From these basic abelian gauge theory formulae, the one-loop contribution to Ω can readily be constructed for Yang-Mills theories, and also for non-gauge theories.     

Classical solutions of Yang-Mills and CP n−1 models with scalar fields

We present a study of classical solutions of the SU(2) Yang-Mills (YM) theory with a massless Higgs doublet, and of the CP ^n?1 model coupled to a scalar field. In both cases the scalar field tends to suppress instantons but not merons (this is a purely classical effect). In the YM theory a static Wu-Yang-like monopole solution with variable magnetic charge is found and its connection with the meron solution of this theory is discussed.     

Casimir Effect on a Finite Lattice

Lattice quantum field theory is a well established branch of modern quantum field theory (QFT). However, it has only peripherally been used for the investigation of Casimir systems — i.e. for systems in which quantum fields are distorted by their interaction with classical background objects. This article presents a Hamiltonian lattice formulation of static Casimir systems at a level of generality appropriate for an introductory investigation. Background structure — represented by a lattice potential V(x) — is introduced along one spatial direction with translation invariance in all other spatial directions. It is simple to extend this formulation to include arbitrary background structure in more than one spatial direction. Following some general analysis two specific finite 1D lattice QFT systems are analyzed in detail. The first has three Dirichlet boundaries at the lattice sites x = 0, l and L (L > l > 0) with vanishing lattice potential V(x) everywhere in between. The vacuum energy and vacuum stress tensor T^μν for this system are calculated in 0 < x < L. Very careful attention must be and is given to renormalization in the (continuum) limit of vanishing lattice constant. Globally and locally this lattice system is seen to closely mimic the corresponding 1D continuum system — as one would hope. Then we introduce a lattice potential V(x) = c/(x — x₀)² centered at x = x₀ < 0 to the left of the boundary at x = 0 and extending through this boundary and the middle Dirichlet boundary at x = l out to the right‐hand boundary x = L > l and beyond. The vacuum energy and T^μν are calculated for this far more complicated system in the region 0 〈 x < L, again with very good results. The internal consistency of the lattice version of this system is carefully examined. Our conclusion is that finite‐lattice formulation provides a powerful and effective tool, capable of solving completely many Casimir systems which could not possibly be handled using continuum methods. This is precisely our reason for introducing it. Future investigations (in one and more dimensions and in dynamical as well as static contexts) will display more fully the power of this method.     

More on Zeta-Function Regularization of High-Temperature Expansions

A recent paper using the Riemann ζ-function to regularize the (divergent) coefficients occurring in the high-temperature expansions of one-loop thermodynamic potentials is extended. This method proves to be a powerful tool for converting Dirichlet-type series Σ_ma_m(x_i)/m^s into powerseries in the dimensionless parameters x_i. The coefficients occurring in the power series are (proportional to) ζ-functions evaluated away from their poles - this is where the regularization occurs. High-temperature expansions are just one example of this highly-nontrivial rearrangement of Dirichlet series into power series form. We discuss in considerable detail series in which a_m(x_i) is a product of trigonometrie, algebraic and Bessel function factors. The ζ-function method is carefully explained, and a large number of new formulae are provided. The means to generalize these formulae are also provided. Previous results on thermodynamic potentials are generalized to include a nonzero constant term in the gauge potential (time component) which can be used to probe the electric sector of temperature gauge theories.     

Weak Neutrino-Lepton Annihilation into Hadrons

An exploratory study of weak neutrino-lepton annihilation into hadrons, v̄_l + l → hadrons is presented. Simple cross-section estimates indicate processes of this type may be observable in a large bubble chamber. We discuss the information one could hope to obtain from such experiments. General formulas for amplitudes and cross sections are given for v̄_l + l → hadrons assuming a point-like V – A interaction. To establish tests of the V – A interaction, we recalculate the annihilation amplitudes assuming a point-like scalar-pseudoscalar or tensor-pseudotensor interaction. The extension to theories with intermediate vector bosons is sketched. We discuss the connection between v̄_l + l → hadrons and e⁺e⁻ → hadrons implied by the conserved vector current hypothesis. We note that in v̄_l + l → rH, K⋆(890), A₁, B creation (these reactions enjoy comparatively large cross sections) the leptonic as well as hadronic couplings of these J = 1 , I = 1/2 or 1 mesons could be determined. A related possibility is the direct creation of new heavy charged J = 1 mesons. The normal J = 1 resonance region could be explored with neutrino energies of the order 500–2000 GeV. For this, and for higher-energy work, a TeV proton accelerator is clearly necessary.     

Cytokine mRNA expression and serum cortisol evaluation during murine lung inflammation induced by Mycobacterium tuberculosis

A model system was characterized for investigating the potential role of cortisol in MTB induced immunopathology. Serum cortisol levels were evaluated in two mouse strains; C57BL/6 mice develop lung granulomas following acute Mycobacterium tuberculosis infection while A/J mice are deficient in this process. Serum cortisol levels were examined post infection, as well as immunoregulatory mRNA expression in the lung, measured using bioluminescent RT-PCR techniques. Prior to infection, the A/J mice constitutively maintain nearly 75&percent; higher serum cortisol than C57BL/6 mice. Both A/J and C57BL/6 mice exhibited approximately 30&percent; reduction in relative serum cortisol following infection. At no time did serum cortisol levels in the A/J fall below constitutive levels in the non-infected C57BL/6. The overall elevated cortisol in the A/J may affect pulmonary immunoresponsiveness; A/J mice exhibited earlier induction of IL-10 and TNF-alpha than C57BL/6 mice, with a relative lack of IL-2 during late infection. Conversely, the C57BL/6 mice demonstrated higher IL-12(p40) and IL-2 messages at the latter stages of disease than the A/J mice. Both mice demonstrated high IFN-&gama; mRNA. The high constitutive serum cortisol in the A/J mice may therefore contribute to establishment of an environment counter-productive to initiation of protective Th1 cell and granulomatous responses.