Integrated cavity output spectroscopy measurements of NO levels in breath with a pulsed room-temperature QCL

A cavity-enhanced spectrometer is developed for detection of exhaled nitric oxide in human breath. A thermoelectrically cooled, pulsed, quantum cascade laser, coupled to a high-finesse cavity, is used for trace-gas measurements. The trace-gas analyzer operates at 5.2 microns and utilizes integrated cavity output spectroscopy. Effective optical path lengths of 1.5 km are achieved in a 50-cm-length cell with a sample volume of 60 mL. The instrument is also capable of simultaneously measuringCO2 concentration in exhaled breath. Measurements were performed on human breath samples as well as simulated breath samples. Here we report a detection limit of ≤ 1 ppbv in 4 s for NO in human breath samples.     

Quantum mechanics of a miniuniverse

From the equations of general relativity for the radius of a closed homogeneous isotropic universe a Schrödinger equation for a particle is obtained. In the case of a universe filled with pressureless matter (dust) the equation is like that for thes states of a hydrogenlike atom. The miniuniverses obtained in this way have quantized masses of the order of the Planck mass.     

W-exchange dominance in neutral B-meson decay

Tests of W-exchange dominance in neutral B-meson decay are developed from the isospin and SU(3) properties of the final state. For B⁰ (d), it is shown that the decay rates into (D⁺ plus anything) and into (F⁺ plus anything) are always equal to one another and never more than $\text{3}\text{2}$ times the rate for (D⁰ plus anything). A similar analysis is applied to B⁰(s), and it is suggested that any of the four possibilities {;ψ, η_c}+(φ, η′) would make a good signal for this meson.     

First-order diffusive effects in nonlinear rate processes

It is shown that first-order diffusive effects can be incorporated immediately into the general initial-value problem solution to a system of nonlinear rate equations.     

Efficacy of cidofovir injection for the treatment of recurrent respiratory papillomatosis

To evaluate the efficacy of intralesional cidofovir injection for the treatment of recurrent respiratory papillomatosis (RRP). It is a prospective, open-label study design. This prospective study included 16 RRP patients, ages 9 to 68 years, who were treated with intralesional injections of cidofovir combined with surgical excision of RRP. The disease states of the patients pretreatment and posttreatment were assessed by assigning RRP severity scores, examining the need for any surgical excision of RRP, and evaluating the presence of RRP upon long-term follow-up. Sixteen patients were treated with cidofovir; however, three were lost to follow-up. Thirteen patients are the subjects of this report. This study group included three pediatric patients. Ten of thirteen patients (76.9%) responded to the treatment and are presently in remission. One patient did not respond, and two patients relapsed after initial success or had a partial response. The responders consisted of eight adults and two children. The mean number of injections the responders received was 3.5, and the average follow-up period of the responders was 25.4 months. No immediate complication of cidofovir treatment was evident. However, three patients were found to have significant vocal fold scarring after long-term follow-up. Cidofovir has been found to be efficacious in treating RRP. Further study regarding long-term follow-up and the assessment of possible side effects after cidofovir intralesional injection for RRP is required.     

Global optimization approach to nonlinear optimal control

To determine the optimum in nonlinear optimal control problems, it is proposed to convert the continuous problems into a form suitable for nonlinear programming (NLP). Since the resulting finite-dimensional NLP problems can present multiple local optima, a global optimization approach is developed where random starting conditions are improved by using special line searches. The efficiency, speed, and reliability of the proposed approach is examined by using two examples.Financial support from the Natural Science and Engineering Research Council under Grant A-3515 as well as an Ontario Graduate Scholarship are gratefully acknowledged. All the computations were done with the facilities of the University of Toronto Computer Centre and the Ontario Centre for Large Scale Computations.     

Ambiguous divisor classes in function fields

Let $\text{L}\text{K}$ be a Galois extension of algegraic function fields in one variable with Galois group G. Let J_K and J_L be the divisor classes of degree zero in K and L, respectively. A study is made of the kernel and cokernel of the natural map from J_K to $\text{J}{}_{\mathrm{L}}{}^{\mathrm{G}}$.     

On the sign of some Dedekind sums

Rademacher asked the following: if $\text{h}{}_1\text{k}{}_1$ and $\text{h}{}_2\text{k}{}_2$ are adjacent terms in a Farey series and if the Dedekind sums s(h₁, k₁) and s(h₂, k₂) are both positive, then is s(h₁ + h₂, k₁ + k₂) ≥ 0? In this note, an infinite family of counter-examples is constructed.     

A parallel algorithm for solving the linear complementarity problem

The concept of multitasking mathematical programs is discussed, and an application of multitasking to the multiple-cost-row linear programming problem is considered. Based on this, an algorithm for solving the Linear Complementarity Problem (LCP) in parallel is presented. A variety of computational results are presented using this multitasking approach on the CRAY X-MP/48. These results were obtained for randomly generated LCP's where thenxn dense matrixM has no special properties (hence, the problem is NP-hard). based on these results, an average time performance ofO(n ⁴) is observed.