Pharmaceutical transition to non-CFC pressurized metered dose inhalers

The production of ozone-depleting chlorofluorocarbons (CFCs) was discontinued on 1 January 1996 for all uses deemed non-essential under the Montreal Protocol. However, the use of CFCs as propellants in pressurized metered dose inhalers (pMDIs) was classed as essential, providing an exemption from the agreement. Following extensive research, the hydrofluoroalkanes (HFA) 134a and 227 were identified as the only suitable replacements for CFC propellants in pMDIs.The drug delivery of pMDIs formulated with HFA 134a as a propellant and containing either salbutamol (100 μg per actuation) or fluticasone propionate (125 and 250 μg per actuation) have been assessed for dose uniformity and particle size distribution.All of the HFA 134a pMDIs delivered doses throughout the life of the canisters that were reproducible and within specified regulatory requirements. Each of the products provided an emitted dose which was within ±25% of the mean value indicating accurate and consistent dosing (93, 112 and 221 μg per metered dose for the salbutamol 100 μg and fluticasone propionate 125 and 250 μg HFA 134a pMDIs, respectively). These findings were unaffected by changing the storage orientation of the pMDI or by using the device in a manner designed to simulate typical patient use. The particle size distributions of HFA 134a pMDI doses did not differ significantly from those of the corresponding CFC pMDIs. As a result of the similar pharmaceutical performance, it is unnecessary to change the label claim dose of active drug when making the transition from a CFC to an HFA 134a pMDI for salbutamol (VentolinTM) and fluticasone propionate (FlixtideTM). A seamless transition to non-CFC pMDIs will help to maintain the confidence of patients and healthcare professionals in asthma therapy

Conformal Spinning Quantum Particles in Complex Minkowski Space as Constrained Nonlinear Sigma Models in U(2,2) and Born's Reciprocity

We revise the use of 8-dimensional conformal, complex (Cartan) domains as a base for the construction of conformally invariant quantum (field) theory, either as phase or configuration spaces. We follow a gauge-invariant Lagrangian approach (of nonlinear sigma-model type) and use a generalized Dirac method for the quantization of constrained systems, which resembles in some aspects the standard approach to quantizing coadjoint orbits of a group G. Physical wave functions, Haar measures, orthonormal basis and reproducing (Bergman) kernels are explicitly calculated in and holomorphic picture in these Cartan domains for both scalar and spinning quantum particles. Similarities and differences with other results in the literature are also discussed and an extension of Schwinger's Master Theorem is commented in connection with closure relations. An adaptation of the Born's Reciprocity Principle (BRP) to the conformal relativity, the replacement of space-time by the 8-dimensional conformal domain at short distances and the existence of a maximal acceleration are also put forward.Comment: 33 pages, no figures, LaTe

Finite-Difference Equations in Relativistic Quantum Mechanics

Relativistic Quantum Mechanics suffers from structural problems which are traced back to the lack of a position operator $\hat{x}$, satisfying $[\hat{x},\hat{p}]=i\hbar\hat{1}$ with the ordinary momentum operator $\hat{p}$, in the basic symmetry group -- the Poincar\'e group. In this paper we provide a finite-dimensional extension of the Poincar\'e group containing only one more (in 1+1D) generator $\hat{\pi}$, satisfying the commutation relation $[\hat{k},\hat{\pi}]=i\hbar\hat{1}$ with the ordinary boost generator $\hat{k}$. The unitary irreducible representations are calculated and the carrier space proves to be the set of Shapiro's wave functions. The generalized equations of motion constitute a simple example of exactly solvable finite-difference set of equations associated with infinite-order polarization equations.Comment: 10 LaTeX pages, final version, enlarged (2 more pages

From 2D Integrable Systems to Self-Dual Gravity

We explain how to construct solutions to the self-dual Einstein vacuum equations from solutions of various two-dimensional integrable systems by exploiting the fact that the Lax formulations of both systems can be embedded in that of the self-dual Yang--Mills equations. We illustrate this by constructing explicit self-dual vacuum metrics on $\R^2\times \Sigma$, where $\Sigma$ is a homogeneous space for a real subgroup of SL(2, \C) associated with the two-dimensional system.Comment: 9 pages, LaTex, no figure

Noncentral extensions as anomalies in classical dynamical systems

A two cocycle is associated to any action of a Lie group on a symplectic manifold. This allows to enlarge the concept of anomaly in classical dynamical systems considered by F. Toppan [in J. Nonlinear Math. Phys. 8, no.3 (2001) 518-533] so as to encompass some extensions of Lie algebras related to noncanonical actions.Comment: arxiv version is already officia

The existence of time

Of those gauge theories of gravity known to be equivalent to general relativity, only the biconformal gauging introduces new structures - the quotient of the conformal group of any pseudo-Euclidean space by its Weyl subgroup always has natural symplectic and metric structures. Using this metric and symplectic form, we show that there exist canonically conjugate, orthogonal, metric submanifolds if and only if the original gauged space is Euclidean or signature 0. In the Euclidean cases, the resultant configuration space must be Lorentzian. Therefore, in this context, time may be viewed as a derived property of general relativity.Comment: 21 pages (Reduced to clarify and focus on central argument; some calculations condensed; typos corrected

On the applicability of constrained symplectic integrators in general relativity

The purpose of this note is to point out that a naive application of symplectic integration schemes for Hamiltonian systems with constraints such as SHAKE or RATTLE which preserve holonomic constraints encounters difficulties when applied to the numerical treatment of the equations of general relativity.Comment: 13 pages, change the title to be more descriptive, typos corrected, added referenc

Geometric quantization of Hamiltonian actions of Lie algebroids and Lie groupoids

We construct Hermitian representations of Lie algebroids and associated unitary representations of Lie groupoids by a geometric quantization procedure. For this purpose we introduce a new notion of Hamiltonian Lie algebroid actions. The first step of our procedure consists of the construction of a prequantization line bundle. Next, we discuss a version of K\"{a}hler quantization suitable for this setting. We proceed by defining a Marsden-Weinstein quotient for our setting and prove a ``quantization commutes with reduction'' theorem. We explain how our geometric quantization procedure relates to a possible orbit method for Lie groupoids. Our theory encompasses the geometric quantization of symplectic manifolds, Hamiltonian Lie algebra actions, actions of families of Lie groups, foliations, as well as some general constructions from differential geometry.Comment: 40 pages, corrected version 11-01-200

The Euler-Lagrange Cohomology and General Volume-Preserving Systems

We briefly introduce the conception on Euler-Lagrange cohomology groups on a symplectic manifold $(\mathcal{M}^{2n}, \omega)$ and systematically present the general form of volume-preserving equations on the manifold from the cohomological point of view. It is shown that for every volume-preserving flow generated by these equations there is an important 2-form that plays the analog role with the Hamiltonian in the Hamilton mechanics. In addition, the ordinary canonical equations with Hamiltonian $H$ are included as a special case with the 2-form $\frac{1}{n-1} H \omega$. It is studied the other volume preserving systems on $({\cal M}^{2n}, \omega)$. It is also explored the relations between our approach and Feng-Shang's volume-preserving systems as well as the Nambu mechanics.Comment: Plain LaTeX, use packages amssymb and amscd, 15 pages, no figure