CONTRIBUIÇÕES DA ECONOMIA DE PROXIMIDADE PARA A COMPREENSÃO DOS PROCESSOS DE INTEGRAÇÃO ENTRE OS AGENTES. ANÁLISE DE DUAS AGLOMERAÇÕES PRODUTIVAS LOCAIS

O artigo aborda a questão das interrações entre atores que coexistem em aglomerações espaciais de empresas.

CONTRIBUIÇÕES DA ECONOMIA DE PROXIMIDADE PARA A COMPREENSÃO DOS PROCESSOS DE INTERAÇÃO ENTRE OS AGENTES. ANÁLISE DE DUAS AGLOMERAÇÕES PRODUTIVAS LOCAIS

O artigo aborda a questão das interações entre atores que coexistem em aglomerações espaciais de empresas. Para abordar essa temática mobilizamos a teoria de Proximidades. Essa teoria mapeia os tipos de proximidades e as suas respectivas contribuições para a construção de interações produtivas. A partir desta fundamentação teórica analisamos duas aglomerações produtivas: a zona industrial e portuária do Pecém e o cluster do Vale dos Vinhedos. Para isso, realizamos pesquisa de campo com a aplicação de questionários semiestruturados. As aglomerações foram selecionadas  por seus antagonismos: regiões de localização, setores produtivos e portes das empresas. Como resultados apontamos que a trajetória de formação das aglomerações, fatores culturais dos atores e as estruturas organizacionais dos arranjos enquadram-se como elementos facilitadores de interação. Desta forma, a proximidade geográfica, apesar de importância incontestável, tem papel secundário para o empreendimento de estratégias coletivas

Effects of sodium hexametaphosphate microparticles or nanoparticles on the growth of saliva-derived microcosm biofilms

Objectives: This study evaluated the effects of sodium hexametaphosphate microparticles (HMPmicro) or nanoparticles (HMPnano) on the growth of saliva-derived microcosm biofilms Materials and methods: Saliva-derived biofilms were formed on glass coverslips for 24 h. Thereafter, Streptococcus mutans (C180-2) was incorporated or not into the biofilms. From that time point onwards, solutions containing 0.2% HMPmicro or HMPnano, combined or not with 220 ppm F, were constantly present in the culture medium. In addition, 220 ppm F alone (220F) and McBain medium without any compound were also tested as positive and negative controls (CTL), respectively. After 96 h, the biofilms were plated on anaerobic blood agar or sucrose agar bacitracin for total and S. mutans CFU-counting, respectively. Biofilms’ lactic acid production was analysed spectrophotometrically. Data were submitted to ANOVA or Kruskal-Wallis’ tests, followed by Student-Newman-Keuls’ test (p<0.05; n=12). Results: HMPmicro or HMPnano led to significantly lower lactic acid production, and significant reductions in total CFU-counting in microcosm biofilms, supplemented or not with S. mutans, in comparison to both controls, with significant differences between 220F and CTL. No significant differences were observed among the groups treated with HMPmicro or HMPnano (with or without F). The same trend was seen for S. mutans CFU-counting, in biofilms supplemented with S. mutans. Conclusions: HMP significantly reduced total and S. mutans CFU counts, as well as lactic acid production by saliva-derived microcosm biofilms. Clinical relevance: These findings in saliva-derived microcosm biofilms suggest that HMP stands as a promising alternative for the control of cariogenic biofilms

Evaluation of Solutions Containing Fluoride, Sodium Trimetaphosphate, Xylitol, and Erythritol, Alone or in Different Associations, on Dual-Species Biofilms

Although the association of polyols/polyphosphates/fluoride has been demonstrated to promote remarkable effects on dental enamel, little is known on their combined effects on biofilms. This study assessed the effects of solutions containing fluoride/sodium trimetaphosphate (TMP)/xylitol/erythritol on dual-species biofilms of Streptococcus mutans and Candida albicans. Biofilms were grown in the continuous presence of these actives alone or in different associations. Quantification of viable plate counts, metabolic activity, biofilm biomass, and extracellular matrix components were evaluated. Overall, fluoride and TMP were the main actives that significantly influenced most of the variables analyzed, with a synergistic effect between them for S. mutans CFUs, biofilm biomass, and protein content of the extracellular matrix (p S. mutans CFUs and biofilm biomass compared with fluoride alone at the same concentration. It can be concluded that fluoride and TMP act synergistically on important biofilm parameters, and their co-administration with xylitol/erythritol significantly impacts S. mutans CFUs and biomass reduction

Antimicrobial Effect of Low-Fluoride Toothpastes Containing Polyphosphate and Polyols: An In Vitro Assessment of Inhibition Zones

This study evaluated the antimicrobial effect of toothpastes containing 200 ppm fluoride (200F), xylitol (X, 16%), erythritol (E, 4%), and sodium trimetaphosphate (TMP, 0.25%), alone or in different associations, against Streptococcus mutans (SM), Lactobacillus casei (LC), Actinomyces israelii (AI), and Candida albicans (CA). Suspensions of the micro-organisms were added to a BHI Agar medium. Five wells were made on each plate to receive toothpaste suspensions at different dilutions. Toothpastes containing no actives (placebo) or 1100 ppm F (1100F) were used as negative and positive controls. Two-way ANOVA and Tukey’s HDS test were used (p p p p < 0.001). The association of polyols and TMP in a low-fluoride toothpaste effectively reduced the growth of cariogenic micro-organisms (SM, CA, and LC), suggesting that this formulation could be an interesting alternative for children due to its low fluoride content