The Effects of UVA-I (340-400 nm), UVA-II (320-340 nm) and UVA-I+II on the Photoisomerization of Urocanic Acid in vivo

Abstract— Ultraviolet B radiation (280-320 nm) can systemically suppress contact hypersensitivity (CHS), delayed type hypersensitivity (DTH) and tumor rejection responses in mice. Several models have been postulated for the initiation of this UVB-induced immune suppression and, although the complete mechanism is unclear, our early studies suggested that initiation is via the activation of a photoreceptor in the skin, identified as urocanic acid (UCA). Recent preliminary data from our laboratory and others indicated that UVA (320-400 nm)-emitting broadband sunlamps can also isomerize UCA but may not lead to immune suppression, in contrast to UVB-emitting sunlamps, which cause both effects. Although the reason for this inconsistency is unknown, the emission spectra of UVA lamps contain differing amounts of UVB, UVA-I (340-400 nm) and UVA-II (320-340 nm) from those of UVB sources. In this study we determined a detailed dose-response for the isomerization of UCA in mouse skin using the UVA-I, UVA-II and UVA-I+II wavelength ranges. The dose-response curves obtained were put on an equal energy basis by quantum correction and the possibility of wavelength interaction for this effect investigated. A simple additive wavelength interaction between UVA-I, UVA-II, and UVA-I+II was observed for trans-UCA photoisomerization. This result indicates that the failure of UVA-I, UVA-II or UVA-I+II radiation to induce immune suppression of the CHS response in an animal model is not due to complex wavelength interactions and/or the presence of an in vivo endogenous photosensitizer of UCA isomerization. Other factors, such as downstream blocking by UVA of the cis -UCA generated signal, may be involved.     

Multiple scattering in random media I. Restricted two-body additive approximation

We present a microscopic theory of the problem of finding the properties of a particle interacting with potentials located at random sites. The sites are governed by a general probability distribution. The starting point is the multiple scattering equations for the amplitude k ₁|T |k ₂ in terms of the individual scattering amplitudes k ₁|T |k ₂. We work with quantitiesA defined by k ₁|T |k ₂=k ₁|T |k ₂exp[i(k ₁–k ₂)R ]. The theory is based on a splitting of the fundamental equation forA into equations for the mean A and the fluctuationsAA . Neglect of the fluctuations yields the quasicrystalline approximation. We rearrange the equation forAA to isolate the collective part of the fluctuations. We then make the simplest microscopic truncation which is thatAA is a restricted two-body additive function of the site positions. With the contribution of the collective fluctuations, this yields results forA that are accurate to ordert ⁴.Work supported in part by the National Science Foundation under Contract No. NSF DMRWork supported in part by the National Science Foundation under Contract No. NSF DMR     

Matroid intersection algorithms

LetM ₁ = (E, 9₁),M ₂ = (E, 9₂) be two matroids over the same set of elementsE, and with families of independent sets 9₁, 9₂. A setI 9₁ 9₂ is said to be anintersection of the matroidsM ₁,M ₂. An important problem of combinatorial optimization is that of finding an optimal intersection ofM ₁,M ₂. In this paper three matroid intersection algorithms are presented. One algorithm computes an intersection containing a maximum number of elements. The other two algorithms compute intersections which are of maximum total weight, for a given weighting of the elements inE. One of these algorithms is primal-dual, being based on duality considerations of linear programming, and the other is primal. All three algorithms are based on the computation of an augmenting sequence of elements, a generalization of the notion of an augmenting path from network flow theory and matching theory. The running time of each algorithm is polynomial inm, the number of elements inE, and in the running times of subroutines for independence testing inM ₁,M ₂. The algorithms provide constructive proofs of various important theorems of matroid theory, such as the Matroid Intersection Duality Theorem and Edmonds' Matroid Polyhedral Intersection Theorem.Research sponsored by the Air Force Office of Scientific Research Grant 71-2076.     

A multi-moment vortex method for 2D viscous fluids

In this paper we introduce simplified, exact, combinatorial formulas that arise in the vortex interaction model found in [33]. These combinatorial formulas allow for the efficient implementation and development of a new multi-moment vortex method (MMVM) using a Hermite expansion to simulate 2D vorticity. The method naturally allows the particles to deform and become highly anisotropic as they evolve without the added cost of computing the non-local Biot–Savart integral. We present three examples using MMVM. We first focus our attention on the implementation of a single particle, large number of Hermite moments case, in the context of quadrupole perturbations of the Lamb–Oseen vortex. At smaller perturbation values, we show the method captures the shear diffusion mechanism and the rapid relaxation (on Re^1/3 time scale) to an axisymmetric state. We then present two more examples of the full multi-moment vortex method and discuss the results in the context of classic vortex methods. We perform numerical tests of convergence of the single particle method and show that at least in simple cases the method exhibits the exponential convergence typical of spectral methods. Lastly, we numerically investigate the spatial accuracy improvement from the inclusion of higher Hermite moments in the full MMVM.     

Bayesian knowledge base tuning

For a knowledge-based system that fails to provide the correct answer, it is important to be able to tune the system while minimizing overall change in the knowledge-base. There are a variety of reasons why the answer is incorrect ranging from incorrect knowledge to information vagueness to incompleteness. Still, in all these situations, it is typically the case that most of the knowledge in the system is likely to be correct as specified by the expert (s) and/or knowledge engineer (s). In this paper, we propose a method to identify the possible changes by understanding the contribution of parameters on the outputs of concern. Our approach is based on Bayesian Knowledge Bases for modeling uncertainties. We start with single parameter changes and then extend to multiple parameters. In order to identify the optimal solution that can minimize the change to the model as specified by the domain experts, we define and evaluate the sensitivity values of the results with respect to the parameters. We discuss the computational complexities of determining the solution and show that the problem of multiple parameters changes can be transformed into Linear Programming problems, and thus, efficiently solvable. Our work can also be applied towards validating the knowledge base such that the updated model can satisfy all test-cases collected from the domain experts.     

Synthesis of 7-Alkoxyquinolines,Coumarins, and Resorufins

Synthesis of the title compounds by treatment of the sodium salts of 7-quinolinol, 7-hydroxycoumarin, and resorufin with alkyl halides is described.     

Addendum to: Capillary Floating and The Billiard Ball Problem

We compare the results of our earlier paper on the floating in neutral equilibrium at arbitrary orientation in the sense of Finn-Young with the literature on its counterpart in the sense of Archimedes. We add a few remarks of personal and social-historical character.