Minimization of total tardiness in no-wait flowshop production systems with preventive maintenance

Efficient business organizations must balance quality, cost, and time constraints in competitive environments. Reflecting the complexity of this task, we consider manufacturing systems including several stages of production chains requiring time measurement. When production scheduling is not prioritized in such enterprises, several negative effects may occur. A corporation may suffer financial penalties as well as negative brand exposure, and thus may find its credibility challenged. Therefore, in this study, we propose constructive methods to minimize a total tardiness criterion, considering preventative maintenance constraints to reflect the reality of industrial practice, focusing on a no-wait flowshop environment in which jobs are successively processed without operational interruptions. In addition to proposing constructive methods to solve the no-wait flowshop production scheduling problem, a metaheuristic is presented as an approach to improve results obtained by constructive methods. Computational experiments were designed and performed to compare several production scheduling algorithms. Among various constructive heuristics considered, an algorithm called HENLL using an insertion logic showed the best performance. The proposed metaheuristic is based on the iterated greedy (IG) search method, and the results obtained demonstrated significant improvement compared to the heuristics alone. It is expected that this study may be used by production planning and control (PPC) professionals to apply the proposed method to schedule production more efficiently. We show that the proposed method successfully presented a better solution in relation to total tardiness, considering the above mentioned environment

Bounded dynamic programming approach to minimize makespan in the blocking flowshop problem with sequence dependent setup times

This paper aims at presenting an algorithm for solving the blocking flow shop problem with sequence dependent setup times (BFSP-SDST) with minimization of the makespan. In order to do so, we propose an adapted Bounded Dynamic Programming (BDP-SN) algorithm as solution method, since the problem itself does not present a significant number of sources in the state-of-art references and also because Dynamic Programming and its variants have been resurfacing in the flowshop literature. Therefore, we apply the modified method to two sets of problems and compare the results computationally and statistically for instances with a MILP and a B&B method for at most 20 jobs and 20 machines. The results show that BDP-SN is promising and outperforms both MILP and B&B within the established time limit. In addition, some suggestions are made in order to improve the method and employ it in parallel research regarding other branches of machine scheduling

Comparison of resazurin microtiter assay performance and BACTEC MGIT 960 in the susceptibility testing of Brazilian clinical isolates of Mycobacterium tuberculosis to four first-line drugs

We assessed the performance of REMA in comparison with BACTEC MGIT 960 in the susceptibility testing of 80 Mycobacterium tuberculosis clinical isolates from Clemente Ferreira Institute against four drugs. REMA proved to be a rapid and accurate method, providing excellent correlation with BACTEC MGIT 960, with the exception of results for the ethambutol drug

Quantitative single cell monitoring of protein synthesis at subcellular resolution using fluorescently labeled tRNA

We have developed a novel technique of using fluorescent tRNA for translation monitoring (FtTM). FtTM enables the identification and monitoring of active protein synthesis sites within live cells at submicron resolution through quantitative microscopy of transfected bulk uncharged tRNA, fluorescently labeled in the D-loop (fl-tRNA). The localization of fl-tRNA to active translation sites was confirmed through its co-localization with cellular factors and its dynamic alterations upon inhibition of protein synthesis. Moreover, fluorescence resonance energy transfer (FRET) signals, generated when fl-tRNAs, separately labeled as a FRET pair occupy adjacent sites on the ribosome, quantitatively reflect levels of protein synthesis in defined cellular regions. In addition, FRET signals enable detection of intra-populational variability in protein synthesis activity. We demonstrate that FtTM allows quantitative comparison of protein synthesis between different cell types, monitoring effects of antibiotics and stress agents, and characterization of changes in spatial compartmentalization of protein synthesis upon viral infection

Platelet Activating Factor Blocks Interkinetic Nuclear Migration in Retinal Progenitors through an Arrest of the Cell Cycle at the S/G2 Transition

Nuclear migration is regulated by the LIS1 protein, which is the regulatory subunit of platelet activating factor (PAF) acetyl-hydrolase, an enzyme complex that inactivates the lipid mediator PAF. Among other functions, PAF modulates cell proliferation, but its effects upon mechanisms of the cell cycle are unknown. Here we show that PAF inhibited interkinetic nuclear migration (IKNM) in retinal proliferating progenitors. The lipid did not, however, affect the velocity of nuclear migration in cells that escaped IKNM blockade. The effect depended on the PAF receptor, Erk and p38 pathways and Chk1. PAF induced no cell death, nor a reduction in nucleotide incorporation, which rules out an intra-S checkpoint. Notwithstanding, the expected increase in cyclin B1 content during G2-phase was prevented in the proliferating cells. We conclude that PAF blocks interkinetic nuclear migration in retinal progenitor cells through an unusual arrest of the cell cycle at the transition from S to G2 phases. These data suggest the operation, in the developing retina, of a checkpoint that monitors the transition from S to G2 phases of the cell cycle

Double-degradable responsive self-assembled multivalent arrays-temporary nanoscale recognition between dendrons and DNA

This article reports self-assembling dendrons which bind DNA in a multivalent manner. The molecular design directly impacts on self-assembly which subsequently controls the way these multivalent nanostructures bind DNA-this can be simulated by multiscale modelling. Incorporation of an S-S linkage between the multivalent hydrophilic dendron and the hydrophobic units responsible for self-assembly allows these structures to undergo triggered reductive cleavage, with dithiothreitol (DTT) inducing controlled breakdown, enabling the release of bound DNA. As such, the high-affinity self-assembled multivalent binding is temporary. Furthermore, because the multivalent dendrons are constructed from esters, a second slow degradation step causes further breakdown of these structures. This two-step double-degradation mechanism converts a large self-assembling unit with high affinity for DNA into small units with no measurable binding affinity-demonstrating the advantage of self-assembled multivalency (SAMul) in achieving highly responsive nanoscale binding of biological targets

Mapeamento de QTLs para características de crescimento e de resistência no cromossomo 14 de bovinos F2 provenientes de um cruzamento Gir x Holandês.

Brazil possesses the largest commercial bovine herd in the world and cattle represents about 43% of agricultural PIB of Brazil. Crossing Bos taurus and Bos indicus species allows the combination of traits of production from the first specie and of rusticity from the second specie for the genetic improvement of the bovines. Due to the economical relevance of livestock in Brazil, the search for regions in the genome that contribute to prodution traits is object of many studies including traits such as meat yield, precocity of growth and many weight measures (eg. birth weight, yearling weight). The endoparasites and ectoparasites have great economical relevance, once the growth losses and production (meat and milk) affect the bovine herd and consequently, the producer and consumer. The objective of this work was to map QTL (Quantitative Trait Loci) for growth traits and for resistance to ectoparasite and endoparasites through the BTA14 scan, using microssatellite markers in a F2 population Holstein x Gyr. The QTL mapping for the trait birth weight (BW) suggested a QTL (P <0.05) at 1 cM from centromere and for the weight at 60 days (P60), a suggestive QTL (P <0.05) was found at 0 cM from centromere. The mapping for resistance to the ectoparasite Boophilus microplus revealed a significant QTL (P<0.01) at 22 cM from centromere but no association was observed for endoparasites. Together, the results found in this work suggest the possibility to map regions of the bovine genome that affect quantitative traits, like growth and resistance, by means of microssatellite markers.Universidade Federal de Sao CarlosO Brasil possui o maior rebanho bovino comercial do mundo e a bovinocultura representa cerca de 43% do PIB agropecuário do Brasil, onde o cruzamento das espécies Bos taurus e Bos indicus permite a combinação de características de produção da primeira espécie e a rusticidade da segunda espécie visando o melhoramento genético dos bovinos. Devido à essa importância econômica da pecuária no Brasil, a procura por regiões no genoma que contribuem para características de produção é objeto de muitos estudos, que incluem características como rendimento de carne, precocidade de crescimento e diversos tipos de pesos. Também importante é o combate aos endoparasitas e ectoparasitas, que têm grande relevância econômica, uma vez que as perdas de crescimento e de produção (carne e leite) afetam o rebanho bovino e consequentemente, o produtor e consumidor. O objetivo deste trabalho foi mapear QTLs (Quantitative Trait Loci) para características de crescimento e de resistência (a ectoparasitas e endoparasitas) por meio da varredura do cromossomo 14 dos bovinos (BTA14), utilizando marcadores microssatélites em uma população F2 Holandês x Gir. O mapeamento de QTLs relacionados à característica peso ao nascimento (PN), permitiu encontrar um QTL sugestivo (P<0,05) a 1 cM do centrômero e para a característica peso aos 60 dias (P60), permitiu encontrar um QTL sugestivo (P<0,05) a 0 cM do centrômero. O mapeamento para característica de resistência ao ectoparasita Boophilus microplus revelou um QTL significativo (P<0,01) a 22 cM do centrômero e à resistência a endoparasitas nenhum QTL foi associado. Os resultados encontrados neste trabalho sugerem que é possível mapear regiões do genoma dos bovinos que afetam características quantitativas, como crescimento e resistência à parasitas, através da utilização de marcadores microssatélites

Construção de um painel com isolados clínicos de Mycobacterium tuberculosis com genes de resistência a quimioterápicos, para o estudo de novas drogas anti-TB

De acordo com a Organização Mundial de Saúde em 2009, 9,27 milhões de novos casos de tuberculose ocorreram em 2007. Destes novos casos, 4,9% eram multidroga resistentes. Muitas pesquisas são realizadas na procura de novas drogas com atividade contra o bacilo da tuberculose, havendo então a necessidade de se entender os mecanismos de ação destes novos compostos. Este projeto objetivou propiciar ferramentas para compreender um pouco mais sobre os mecanismos de ação de novas drogas. Isolados clínicos de M. tuberculosis foram caracterizados quanto ao seu perfil de susceptibilidade aos fármacos do esquema terapêutico e foram determinadas as mutações responsáveis por estas resistências. Com os isolados caracterizados, foi construído um painel de M. tuberculosis. Pelo REMA, os isolados foram analisados quanto ao seu perfil de susceptibilidade aos fármacos (INH, RMP, STR e ETB) e avaliados quanto à presença de mutações nos genes de resistência (inhA, katG, ahpC, rpoβ, rpsL, rrs e embB) empregando a PCR-SSCP. Pelo REMA foram avaliados 80 isolados clínicos, sendo observada a resistência a INH em 74,7%, a RMP em 51,2%, a STR em 53,7% e ao ETB em 58,7%. Nos isolados resistentes, a porcentagem de mutações encontradas nos genes foi de 20,6% para inhA, 50% para katG, 6,3% para ahpC, 60% para rpoβ, 20% para rpsL e 0% para rrs e embB. Um painel com 12 isolados foi testado frente a três novos compostos, dois derivados de INH (Cu-INH1 e Cu-INH2) e um de RMP (Cu-RMP). Verificou-se que os isolados resistentes a INH foram também resistentes a Cu-INH1 e Cu-INH2. A mesma situação foi verificada em relação à RMP, com o composto Cu-RMP. Provavelmente, estes novos compostos têm os mesmos mecanismos de ação da INH e da RMP, que são os fármacos que lhes deram origemAccording to World Health Organization in 2009, 9.27 million new TB cases occurred in 2007. Among these new cases, 4.9% were multidrug resistant. Many surveys are conducted in the search for new drugs with activity against the tuberculosis bacillus, therefore there is a need to understand the action mechanism of these new compounds. This project aimed to provide tools to understand about the action mechanisms of new drugs. M. tuberculosis clinical isolates were analyzed for their susceptibility profile to drugs, mutations responsible for resistance and a panel of these characterized isolates. The isolates were analyzed for susceptibility profile to drugs (INH, RIF, STR and ETB) and evaluated for presence of mutations in the resistance genes (inhA, katG, ahpC, rpoβ, rpsL, rrs and embB) applying the PCR-SSCP. REMA evaluated 85 clinical isolates and the resistance was observed in 74.7% to INH, 51.5% to RIF, 53.7% to STR and 58.7% to ETB. In the resistant isolates, percentage of mutations found in the genes was 20.6% for inhA, 50% for katG, 6.3% for ahpC, 60% for rpoβ, 20% for rpsL and 0% for rrs and embB. A panel of 12 isolates was tested against three new compounds, two INH-derivatives (Cu-INH1 and Cu-INH2) and one RMP-derivative (Cu-RMP). The isolates resistant to INH were also resistant to Cu-INH1 and Cu-INH2 compounds. The same situation was verified in relation to the RMP with the Cu-RMP compound, indicating that probably these three new compounds have the same action mechanism of INH and RMP drugsConselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

Procedure structuring for programming aircraft maintenance activities

Purpose – This paper aims to exemplify the use of project management tools in the scheduling of aircraftmaintenance activities. This process is known as maintenance, repair and overhaul and it has gainedimportance within the aeronautical sector due to its expected growth in the coming years; however, it alsofaces increasing competitiveness in its market. This fact gives rise to the need of acting in maintenancemanagement and seeking lower costs while maintaining the quality of the service provided. The purpose ofthis paper is to propose the structuring of a procedure that aims to reduce the total maintenance time(downtime) and guarantee the delivery of the aircraft on time.Design/methodology/approach – The paper, through a case study at a Brazilian aircraft maintenancecenter, used critical path method and critical chain project management, the latter being derived from thetheory of constraints, with the purpose of analyzing resources systematically and synchronizing the activitiesin the precedence network.Findings – As a result, it is shown that downtime can be reduced from 11 to 5 days and improvements areproposed to achieve greater market competitiveness.Originality/value – This paper demonstrates the competitive advantage that resulted from the applicationof project management tools in the aircraft maintenance planning and execution

Silver ion release from electrodes of nanotubes of TiO2 impregnated with Ag nanoparticles applied in photoelectrocatalytic disinfection

Self-organized TiO2 nanotubes arrays electrodes were impregnated with 0-16% of Ag nanoparticles (Ti/TiO2-Ag) using different procedures. The electrodes were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX) and photocurrent vs potential curves. The best results were obtained by electrode prepared by photochemical reduction, after immersion in a solution AgNO3 0.05 M (pH 8). The monitoring of Ag+ lixiviation by anodic stripping voltammetry at glassy carbon electrode indicated that a maximum of 2.5 x 10(-6) M is released in the first 40 min of treatment, but it is neglected when used subsequently. Moreover, the antimicrobial behavior of electrodes Ti/TiO2-Ag applied in photoelectrocatalysis presented 100% disinfection in 3 min by using UV irradiation and 99.6% in 30 min with visible irradiation. In addition, the analysis of silver in solution along the reaction shows a negligible lixiviation and a high stability of the surface silver deposits. Crown Copyright (C) 2014 Published by Elsevier B.V. All rights reserved.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq