Measuring Tumor Cycling Hypoxia and Angiogenesis Using a Side-firing Fiber Optic Probe

Hypoxia and angiogenesis can significantly influence the efficacy of cancer therapy and the behavior of surviving tumor cells. There is a growing demand for technologies to measure tumor hypoxia and angiogenesis temporally in vivo to enable advances in drug development and optimization. This paper reports the use of frequency-domain photon migration with a side-firing probe to quantify tumor oxygenation and hemoglobin concentrations in nude rats bearing human head/neck tumors administered with carbogen gas, cycling hypoxic gas or just room air. Significant increase (with carbogen gas breathing) or decrease (with hypoxic gas breathing) in tumor oxygenation was observed. The trend in tumor oxygenation during forced cycling hypoxia (CH) followed that of the blood oxygenation measured with a pulse oximeter. Natural CH was also observed in rats under room air. The studies demonstrated the potential of the technology for longitudinal monitoring of tumor CH during tumor growth or in response to therapy

Abstract Improving the Computational Performance of ILP-based Problems

Many interesting problems in VLSI design are computationally extremely difficult, and as such, there exist no efficient (read polynomial time) algorithms for these problems. Such problems include placement, routing, scheduling and partitioning. A commonly used technique for solving these problems is to model them as an Integer Linear Programming (ILP) problem, and to then solve the resulting model using a generic ILP solver. So far, improving the computational efficiency of these problems was considered equivalent to improving the model. In this paper, we show that large performance improvements can be achieved by incorporating problem specific informations into the ILP solver itself. While the techniques that we present are general in nature, for the sake of concreteness, we will illustrate them by applying them to scheduling problems in high-level synthesis. It will be shown that there is a lot of problem specific information that can be incorporated into the model solver, and that doing so actually improves the performance considerably. We will present experimental results to show that the problem specific ILP solver is considerably faster, often showing improvements by a factor of 1000 in execution time.

A Fast Approach to Computing Exact Solutions to the Resource-Constrained Scheduling Problem

This paper presents an algorithm that substantially reduces the computational effort required to obtain the exact solution to the Resource Constrained Scheduling (RCS) problem. The reduction is obtained by (a) using a branch-and-bound search technique, which computes both upper and lower bounds, and (b) using ecient techniques to accurately estimate the possible time-steps at which each operation can be scheduled and using this to prune the search space. Results on several benchmarks with varying resource constraints indicate the clear superiority of the algorithm presented here over traditional approaches using integer linear programming, with speed-ups of several orders of magnitude

Tighter Lower Bounds for Scheduling Problems in High-Level Synthesis

This paper presents new results on lower bounds for the scheduling problem in highlevel synthesis. While several techniques exist for lower bound estimation, comparisons among the techniques have been experimental with few guarantees on the quality of the bounds. In this paper, we present new bounds and a theoretical comparison of these with existing bounds. For the resource-constrained scheduling problem, we present a new algorithm which generalizes the bounding techniques of Langevin and Cerny [13] and Rim and Jain [18]. This algorithm is shown to produce bounds that are provably tighter than other existing techniques. For the time constrained scheduling problem, we show how to generate the tightest possible bounds that can be derived by ignoring the precedence constraints by solving a linear programming formulation. These bounds are therefore guaranteed to be tighter than the bounds generated by the techniques of Fernandez-Bussell [4] or Sharma-Jain [19]. As a result, we show that t..

Kinetics of Oxidation of Benzoin by Ceric Ammonium Nitrate In Aqueous Acetic Acid

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International Winter Workshop on Differential Equations and Numerical Analysis

This book offers an ideal introduction to singular perturbation problems, and a valuable guide for researchers in the field of differential equations. It also includes chapters on new contributions to both fields: differential equations and singular perturbation problems. Written by experts who are active researchers in the related fields, the book serves as a comprehensive source of information on the underlying ideas in the construction of numerical methods to address different classes of problems with solutions of different behaviors, which will ultimately help researchers to design and assess numerical methods for solving new problems. All the chapters presented in the volume are complemented by illustrations in the form of tables and graphs