Synthesis of trans-1,2-diphenyl-3,4-bis[4-(2,6-diphenyl-4H- pyranylidenyl)]cyclobutane: correction and structure proof

The reaction of phenyl lithium acetylide ($\text{2}$) with 2,6-diphenylpyrylium perchlorate ($\text{1}$) is solvent dependent. With diethyl ether as solvent, the isolated product differed from that previously reported and is reassingned as 2,6-diphenyl-4-phenylacetylenyl-4$\text{H}$-pyran ($\text{5}$). On the other hand, in THF the title compound ($\text{6}$) was obtained; its structure confirmed by single-crystal x-ray crystallography.     

Amphiphilic poly-n-vinyl-2-pyrrolidone: Synthesis,properties, nanoparticles

Water-soluble amphiphilic polymers based on N-vinyl-2-pyrrolidone (Amph-PVP) have been synthesized. Amphiphilic diblock polymers have been obtained via a single-step technique. For the synthesized amphiphilic polymers, the critical concentrations of mycelium formation (CCM) have been determined. The structure of the polymers obtained was confirmed by IR and NMR spectroscopy. The critical concentration of micelle formation (CCM) for the synthesized polymers has been found to be in the micromolar range. The fluorescent dye 1,1′-dioctadecyl-3,3,3′,3′-tetramethylindocarbocyanine perchlorate (Dil) was chosen as a model substance for the synthesis of nanoparticles. Micellar particles were obtained via an ultrasonic technique followed by evaporation of the organic solvent (emulsion method).     

Allocation of Marketing Effort Among <Emphasis Type="Italic">P</Emphasis> Substitutional Products in <Emphasis Type="Italic">N</Emphasis> Territories<Superscript>†</Superscript>

Frequently, companies face the problem of allocating a given marketing budget in order to maximize their total returns. In this paper we examine the problem of allocating marketing effort, such as advertising, among P substitutional products, distributed in N different sales territories. Two models are discussed. In the first model it is assumed that at most one product is promoted in each sales territory. It is shown that a simple algorithm leads to at least a local optimum in a finite number of steps. In the second model, the restriction of one product per territory is eliminated. Applying a concept of effective effort, the model is transformed to an equivalent separable programming problem, solvable by a “single-pass” algorithm for various forms of response functions. Furthermore, a concept of successive modifications of the objective function is discussed.     

Synthesis of 1-acyloxyindolizines. Correction of a structure misassignment

The assignment by Lown of a 3-acyloxyindolizine structure to the product of the reaction of diphenylcyclopropenone and pyridine is shown to be in error. Both 1- and 3-acyloxyindolizines were prepared and their structures established by X-ray analysis.     

Design of Stacked Self-Healing Rings Using a Genetic Algorithm

Ring structures in telecommunications are taking on increasing importance because of their self-healing properties. We consider a ring design problem in which several stacked self-healing rings (SHRs) follow the same route, and, thus, pass through the same set of nodes. Traffic can be exchanged among these stacked rings at a designated hub node. Each non-hub node may be connected to multiple rings. It is necessary to determine to which rings each node should be connected, and how traffic should be routed on the rings. The objective is to optimize the tradeoff between the costs for connecting nodes to rings and the costs for routing demand on multiple rings. We describe a genetic algorithm that finds heuristic solutions for this problem. The initial generation of solutions includes randomly-generated solutions, complemented by seed solutions obtained by applying a greedy randomized adaptive search procedure (GRASP) to two related problems. Subsequent generations are created by recombining pairs of parent solutions. Computational experiments compare the genetic algorithm with a commercial integer programming package.     

A Resource Allocation Approach for the Generation of Service-Dependent Demand Matrices for Communications Networks

Estimating point-to-point demands from partially available information, such as total demand volumes originating and terminating at nodes and traffic volumes routed on links, has significant applications in various areas, such as communications network planning and transportation planning. Existing methods include matrix and link scaling methods, statistical methods, more complex mathematical programming models, and forecasting using demographic data. We present a new mathematical programming model based on equitable resource allocation. The model considers multiple services, e.g., data, video, and voice, and generates a point-to-point demand matrix for each service. Originating and terminating demands for each service and link loads, aggregated over all services, are viewed as resources. Each point-to-point demand is associated with a performance function that measures its weighted, normalized deviation from a target defined by a service-dependent community of interest matrix. The model formulation has a lexicographic minimax objective function and multiple knapsack resource constraints. The model has an intuitively appealing interpretation and a specialized algorithm can generate demand matrices for large network problems very fast.     

A Lot-sizing Model for Just-in-time Manufacturing

We consider the problem of determining lot sizes of multiple items that are manufactured by a single capacitated facility. The manufacturing facility may represent a bottleneck processing activity on the shop floor or a storeroom that provides components to the shop floor. Items flow from the facility to a downstream facility, where they are assembled according to a specified mix. Just-in-time (JIT) manufacturing requires a balanced flow of items, in the proper mix, between successive facilities. Our model determines lot sizes of the various items based on available capacity and four attributes of each item: demand rate, holding cost, set-up time and processing time. Holding costs for each item accrue until the appropriate mix of items is available for shipment downstream. We develop a lot-sizing heuristic that minimizes total holding cost per time unit over all items, subject to capacity availability and the required mix of items.     

Solubilization of prothionamide with micelles of an amphiphilic acrylic acid oligomer with thiohexyl terminal groups and preparation of postoperative cavity filling formulations

An amphiphilic oligomer was prepared by telomerization of acrylic acid in the presence of n-hexyl mercaptan. The structure, molecular weight, critical micelle concentration, and ζ-potential of the oligomer, and also its particle-size distribution in aqueous solution were determined. The product allows solubilization of prothiondamide antituberculosis drug. A procedure was suggested for preparing a filling formulation containing prothionamide for filling postoperative cavities in connective tissue.     

An Extended Model for the Optimal Sizing of Records

In previous work, Erickson and Luss examined the problem of optimally sizing computer records so as to minimize wasted space. They assumed that a fixed number of record sizes can be used to store messages of various lengths. If a message cannot be stored in any single record, it is stored in multiple records of the same size. However, the record size used to accommodate divided messages is not used to store any message that fits into any of the other record sizes. Here, we relax the latter constraint and allow the record size designated to store divided messages to store also other messages. A dynamic programming algorithm that finds the optimal record sizes is presented. However, since the computational effort needed to find the optimal record sizes is large, we also derive bounds for the optimal solution and give a heuristic algorithm that provides near optimal solutions.