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91.
Artur Alves Pessoa Peter M. Hahn Monique Guignard Yi-Rong Zhu 《European Journal of Operational Research》2010
In this paper, we propose two exact algorithms for the GQAP (generalized quadratic assignment problem). In this problem, given M facilities and N locations, the facility space requirements, the location available space, the facility installation costs, the flows between facilities, and the distance costs between locations, one must assign each facility to exactly one location so that each location has sufficient space for all facilities assigned to it and the sum of the products of the facility flows by the corresponding distance costs plus the sum of the installation costs is minimized. This problem generalizes the well-known quadratic assignment problem (QAP). Both exact algorithms combine a previously proposed branch-and-bound scheme with a new Lagrangean relaxation procedure over a known RLT (Reformulation-Linearization Technique) formulation. We also apply transformational lower bounding techniques to improve the performance of the new procedure. We report detailed experimental results where 19 out of 21 instances with up to 35 facilities are solved in up to a few days of running time. Six of these instances were open. 相似文献
92.
T. S. Porto P. P. Marques C. S. Porto K. A. Moreira J. L. Lima-Filho A. Converti A. Pessoa A. L. F. Porto 《Applied biochemistry and biotechnology》2010,160(4):1057-1064
The ascorbate oxidase is the enzyme used to determine the content of ascorbic acid in the pharmaceutical and food industries
and clinics analyses. The techniques currently used for the purification of this enzyme raise its production cost. Thus, the
development of alternative processes and with the potential to reduce costs is interesting. The application of aqueous two-phase
system is proposed as an alternative to purification because it enables good separation of biomolecules. The objective of
this study was to determine the conditions to continuously pre-purify the enzyme ascorbate oxidase by an aqueous two-phase
system (PEG/citrate) using rotating column provided with perforated discs. Under the best conditions (20,000 g/mol PEG molar
mass, 10% PEG concentration, and 25% citrate concentration), the system showed satisfactory results (partition coefficient,
3.35; separation efficiency, 54.98%; and purification factor, 1.46) and proved suitable for the pre-purification of ascorbate
oxidase in continuous process. 相似文献
93.
Maria Conceição M. Torres Raimundo Braz‐Filho Edilberto R. Silveira Jaécio Carlos Diniz Francisco Arnaldo Viana Otília Deusdênia L. Pessoa 《Helvetica chimica acta》2010,93(2):375-381
Two new terpenoids, the bisnorditerpene rel‐(5β,8α,10α)‐8‐hydroxy‐13‐methylpodocarpa‐9(11),13‐diene‐3,12‐dione ( 1 ) and the guaiane sesquiterpene rel‐(1R,4S,6R,7S,8aR)‐decahydro‐1‐(hydroxymethyl)‐4,9,9‐trimethyl‐4,7‐(epoxymethano)azulen‐6‐ol ( 2 ), together with seven known compounds, were isolated from Croton regelianus var. matosii. The structures of the isolated compounds were determined by HR‐ESI‐TOF and a combination of 1D‐ and 2D‐NMR experiments. 相似文献
94.
dos Santos Junior Valdeci Elias Targino Andrea Gadelha Ribeiro Flores Miguel Angel Pelagio Rodríguez-Díaz Joan Manuel Teixeira Joás Araújo Heimer Mônica Vilela Pessoa Hilzethe de Luna Freire Galembeck André Rosenblatt Aronita 《Research on Chemical Intermediates》2017,43(10):5889-5899
Research on Chemical Intermediates - Silver nanoparticles stabilized with chitosan biopolymer are a new antibacterial agent for treatment of caries. To determine whether the size and morphology of... 相似文献
95.
Diego Pecin Artur Pessoa Marcus Poggi Eduardo Uchoa 《Mathematical Programming Computation》2017,9(1):61-100
The best performing exact algorithms for the capacitated vehicle routing problem developed in the last 10 years are based in the combination of cut and column generation. Some authors only used cuts expressed over the variables of the original formulation, in order to keep the pricing subproblem relatively easy. Other authors could reduce the duality gaps by also using a restricted number of cuts over the master LP variables, stopping when the pricing becomes prohibitively hard. A particularly effective family of such cuts are the subset row cuts. This work introduces a technique for greatly reducing the impact on the pricing of these cuts, thus allowing much more cuts to be added. The newly proposed branch-cut-and-price algorithm also incorporates and combines for the first time (often in an improved way) several elements found in previous works, like route enumeration and strong branching. All the instances used for benchmarking exact algorithms, with up to 199 customers, were solved to optimality. Moreover, some larger instances with up to 360 customers, only considered before by heuristic methods, were solved too. 相似文献
96.
Tatiane Skeika Crislaine Marcovicz Shirley Nakagaki Sérgio Toshio Fujiwara Karen Wohnrath Noemi Nagata Christiana A. Pessoa 《Electroanalysis》2007,19(24):2543-2550
This paper shows an application of a first generation porphyrin, FeTPPCl 5,10,25,20‐tetraphenylporphyrin iron(III) chloride (FeTPPCl or FeTPP+) immobilized on a inorganic matrix, SiO2/Nb2O5 (niobium oxide grafted on silica gel surface, designated as SiNb) to the preparation of a carbon paste electrode (CPE). The carbon paste modified with a FeTPP+ immobilized on SiO2/Nb2O5 (SiNb), designated as CPE/SiNb/FeTPP, was applied for simultaneous electrochemical determination of dopamine (DA) and ascorbic acid (AA). Because of the overlapping of the voltammetric peaks of DA and AA, the multivariate calibration methodology based on partial least square regression (PLSR) was proposed. The data pre‐treatment used in this process was mean centering and to choose the principal components number a cross validation procedure was used (leave‐one‐out). Five principal components were necessary to obtain the lowest PRESS (prediction residual error sum of squares). The statistics showed that this model explains approximately 95.2% of the variance from the data set. Using this model, high correlation between actual and predicted concentrations was observed, mainly for higher dopamine (maximum relative error of 8%) and ascorbic acid (maximum relative error of 10%) concentrations. For low analytes concentrations the relative error increases to 35% for AA. Considering the similarity of the voltammetric response of the analytes, the results obtained were satisfactory and showed the promissory capability of the CPE/SiNb/FeTPP coupled multivariate calibration methods for simultaneous voltammetric analysis of DA and AA. 相似文献
97.
Tams Kiss Tams Jakusch Dominik Hollender gnes Drnyei va A. Enyedy Joo Costa Pessoa Hiromu Sakurai Alfredo Sanz-Medel 《Coordination chemistry reviews》2008,252(10-11):1153
The possible transformations of antidiabetic vanadium(IV) complexes in the organism are discussed. These reactions involve absorption processes in the gastrointestinal tract, transport in the blood stream and interactions with endogenous binding molecules in the glucose-metabolizing cells. Modeling studies were mostly used to determine the actual chemical form of VO(IV) complexes in various biological environments. The results suggest that decomposition and subsequent ternary complex formation with endogenous or exogenous ligands in the organism affects the absorption efficacy of the originally neutral VO(IV) compounds considerably. During transport in the blood stream, transferrin displaces the carrier ligands from the VO(IV) compounds and plays an important role in transporting VO(IV) to the cell. In the cell, vanadium undergoes redox interaction with glutathione and complexation with adenosine 5′-triphosphate (the two important cell components present in mM concentration). In vitro and in vivo biological results confirmed some of the basic findings obtained from the modeling. 相似文献
98.
99.
Pessoa Adalberto Vitolo Michele Hustedt Helmut 《Applied biochemistry and biotechnology》1996,57(1):699-709
Applied Biochemistry and Biotechnology - The scale-up of inulinase production in aerated cultures ofCandida kefyr DSM 70106 was studied, taking into account the criterion of maintainingK L a... 相似文献
100.
4OR - The Capacitated Vehicle Routing Problem (CVRP) is a classical combinatorial optimization problem that aims to serve a set of customers, using a set of identical vehicles, satisfying the... 相似文献