A Full-Newton Step Infeasible Interior-Point Algorithm Based on Darvay Directions for Linear Optimization

We present a full-Newton step primal-dual infeasible interior-point algorithm based on Darvay’s search directions. These directions are obtained by an equivalent algebraic transformation of the centering equation. The algorithm decreases the duality gap and the feasibility residuals at the same rate. During this algorithm we construct strictly feasible iterates for a sequence of perturbations of the given problem and its dual problem. Each main iteration of the algorithm consists of a feasibility step and some centering steps. The starting point in the first iteration of the algorithm depends on a positive number ξ and it is strictly feasible for a perturbed pair, and feasibility steps find strictly feasible iterate for the next perturbed pair. By using centering steps for the new perturbed pair, we obtain strictly feasible iterate close to the central path of the new perturbed pair. The algorithm finds an ?-optimal solution or detects infeasibility of the given problem. The iteration bound coincides with the best known iteration bound for linear optimization problems.     

Preparation and biodistribution study of technetium-99m-labeled quercetin as a potential radical scavenging agent

Free radicals and oxidative stress are the primary causes of several chronic diseases such as cancer and heart disease. Quercetin is a natural compound with potent antioxidant activity. We have prepared and evaluated technetium-99m (^99mTc)-labeled quercetin as a potential radical scavenging radiotracer. A ^99mTc-quercetin complex was prepared using quercetin, SnCl₂ and Na^99mTcO₄ in a buffered solution over 30 min. The participation coefficient was measured in octanol and queues solutions. The stability was determined in phosphate buffered saline and serum. The biodistribution in normal mice was evaluated at 0.5, 2, 6 and 24 h post-injection. The radiochemical purity (>99%) was determined by thin layer chromatography (TLC) in normal saline solution as the mobile phase. It has a log P of 0.204. It was mainly cleared by the kidneys and showed negligible brain uptake at four time points measured post-injection. The pharmacological properties of quercetin, mainly its free radical scavenging, may potentially cat as a radiopharmaceutical agent for radical-targeted imaging of tissue with high levels of reactive oxygen species.     

A novel organocatalytic multi-component reaction: an efficient synthesis of polysubstituted pyrano-fused spirooxindoles

A practical, simple, and efficient method for the synthesis of pyrano-fused spirooxindoles via an organocatalytic three-component reaction of isatins, malononitrile, and dialkyl acetylenedicarboxylate in the presence of 3,4-dimethylaniline as an organocatalyst in ethanol is reported. The structures of these products are confirmed by IR, ¹H NMR and ¹³C NMR spectroscopy, mass spectrometry, and single-crystal X-ray diffraction studies.     

Erratum: Investigation of drug release and 1H‐NMR analysis of the in situ forming systems based on poly(lactide‐co‐glycolide)

This paper was published online on 10 October 2008 (DOI: 10.1002/pat.1279 ) and appears in the January 2009 issue (Vol. 20, No. 1, pp. 48‐57). The following changes should be recognized: The second corresponding author should be changed to M. Rafiena. ** Correspondence to: M. Rafienia, Medical Physics and Medical Engineering Department, Isfahan University of Medical Sciences (IUMS), P.O. Box 81744‐176, Isfahan, Iran. E‐mail: m_rafienia@med.mui.ac.ir     

Density Based Problem Space Search for the Capacitated Clustering p-Median Problem

In the Capacitated Clustering Problem (CCP), a given set of n weighted points is to be partitioned into p clusters such that, the total weight of the points in each cluster does not exceed a given cluster capacity. The objective is to find a set of p centers that minimises total scatter of points allocated to them. In this paper a new constructive method, a general framework to improve the performance of greedy constructive heuristics, and a problem space search procedure for the CCP are proposed. The constructive heuristic finds patterns of natural subgrouping in the input data using concept of density of points. Elements of adaptive computation and periodic construction–deconstruction concepts are implemented within the constructive heuristic to develop a general framework for building efficient heuristics. The problem-space search procedure is based on perturbations of input data for which a controlled perturbation strategy, intensification and diversification strategies are developed. The implemented algorithms are compared with existing methods on a standard set of bench-marks and on new sets of large-sized instances. The results illustrate the strengths of our algorithms in terms of solution quality and computational efficiency.     

Stability of Cosserat fluid motions

We obtain criteria of stability of the unsteady motion of an incompressible Cosserat fluid in an arbitrary time-dependent domain, employing a general energy method due to J. Serrin. It is shown that the original motion is stable if R _e ² 80 + 12800 C ₀ or if R _e80 + 6400 C ₀. The quantities R _e and C ₀ are the Reynolds number and Cosserat number, respectively, and - is the lower bound for the eigenvalues of the strain rate tensor D _ij.The theorems established for the stability criteria are universal in the sense that they do not depend either on the shape of the domain or on the distribution of the basic field variables. Finally an experimental scheme is proposed to determine the upper bound of the Cosserat number and consequently the characteristic length of a Cosserat fluid.     

Tautomerization of pyrido[2′,1′:2,3]imidazo[4,5-B]quinoline-12-ylcyanide: A DFT study

The titled imidazo compound can exist as three tautomers: OH, CH, and NH forms. Firstly, the OH tautomer is produced, which can be tautomerized to the CH and NH tautomers via the intramolecularproton transfer. Herein, employing density functional theory and handling the solvent effects with the PCM model, the structural parameters, energy behavior, and also tautomerization mechanism of the tautomers are investigated. Based on the DFT results and the obtained-AIM parameters, the CH tautomer is considered to be the most stable one. Also, the CH tautomer is a kinetically and thermodynamically controlled product in tautomerization of the OH tautomer in a methanol solution.