Polysaccharide production and biofilm formation by Pseudomonas fluorescens: effects of pH and surface material

Although the synthesis of extracellular polysaccharides was first recognized in certain bacterial cultures a long time ago, its role in bacterial adhesion is still subject to some debate. Several fermentation batch cultures were performed under different conditions of pH (pH 7, maintained with NaOH and HCl; pH 7 in phosphate buffer, and without pH control) in order to study the relation between the production of extracellular polysaccharides and biofilm formation on polymeric slides suspended in the culture medium. The polymers used were polystyrene, polypropylene, polyethylene and poly(vinyl chloride). The maximum amount of exopolysaccharides in the culture medium occurs at pH 7, although slightly thicker biofilms seem to be formed when there is no pH control. The biofilms were analysed by scanning electron microscopy and by wavelength dispersion spectroscopy. Biofilm morphology seems to be much more dependent on the type of substratium than on the pH of the medium; for different pH values, a polymeric network can be more clearly observed on biofilms formed on all surfaces except poly(vinyl chloride)

New genetic algorithm approach for the min-degree constrained minimum spanning tree

A novel approach is proposed for the NP-hard min-degree constrained minimum spanning tree (md-MST). The NP-hardness of the md-MST demands that heuristic approximations are used to tackle its intractability and thus an original genetic algorithm strategy is described using an improvement of the Martins-Souza heuristic to obtain a md-MST feasible solution, which is also presented. The genetic approach combines the latter improvement with three new approximations based on different chromosome representations for trees that employ diverse crossover operators. The genetic versions compare very favourably with the best known results in terms of both the run time and obtaining better quality solutions. In particular, new lower bounds are established for instances with higher dimensions.info:eu-repo/semantics/submittedVersio

Preliminary studies for the aplication of Thymbra capitata essential oil as potential antimicrobial agent in Bacterial Vaginosis

Bacterial vaginosis (BV) is the most common gynecological clinical condition in women in reproductive age, and has been associated with an increased risk of development of preterm labor, spontaneous abortion, and several sexually transmitted diseases such as HIV [1]. BV is not only a condition that involves excessive growth of anaerobic microorganisms, but also involves the presence of an adherent biofilm [2]. Despite its high prevalence, the aetiology of BV remains unknown, but frequently Gardnerella vaginalis is the main microorganism associated with this disorder [3], that is often the main species in biofilms presented in BV [4]. These results led to the theory that the microorganisms that form biofilms may be relevant for the aetiology of BV [5]. Traditionally, the treatment of BV involves the antibiotics metronidazole, clindamicin or tinidazole [6]. However, the recurrence rate remains high and this can be related to the biofilm-forming ability of G. vaginalis [5]. In this context, recently it was reported that natural compounds, such as Thymbra capitata essential oil, can reduce the activity of biofilms [7]. To test if T. capitata could be used in the treatment of BV, we determined the biofilm-forming ability and the effect of essential oil in seven strains of G. vaginalis isolated from women with BV. Thus, the biofilm-forming ability was assessed under anaerobic conditions for 48 hours, allowing each strain to form biofilm. These assays revealed that in fact, G. vaginalis strains produced moderate to tenacious biofilm. We then determined the sensibility of the tested bacteria to the common antibiotics used to treat BV. Not surprisingly, most of strains were resistant of metronidazole and tinidazole which are more commonly administered. However half of strains were sensitive to clindamicin. We then evaluated the antibacterial activity of essential oil upon G. vaginalis strains, determining minimum inhibitory concentration (MIC) and minimum lethal concentration (MLC). The T. capitata essential oil exhibited a potent anti-G. vaginalis effect, which was confirmed by the low values of MIC (0.16 µL.mL-1) and MLC (0.16 - 0.31 µL.mL-1). To conclude, these results showed that T. capitata essential oil presents a strong antibacterial activity upon antibiotic resistant and biofilm forming of G. vaginalis strains, reinforcing the potential interest of this essential oil as antimicrobial agent in the treatment of BV

Brief report on double-chamber syringes patents and implications for infusion therapy safety and efficiency

This review aimed to map the existing patents of double-chamber syringes that can be used for intravenous drug administration and catheter flush. A search was conducted in the Google patents database for records published prior to 28 October 2020, using several search terms related to double-chamber syringes (DCS). Study eligibility and data extraction were performed by two independent reviewers. Of the initial 26,110 patents found, 24 were included in this review. The 24 DCS that were found display two or more independent chambers that allow for the administration of multiple solutions. While some of the DCS have designated one of the chambers as the flushing chamber, most patents only allow for the sequential use of the flushing chamber after intravenous drug administration. Most DCS were developed for drug reconstitution, usually with a freeze-dried drug in one chamber. Some patents were designed for safety purposes, with a parallel post-injection safety sheath chamber for enclosing a sharpened needle tip. None of the DCS found allow for a preand post-intravenous drug administration flush. Given the current standards of care in infusion therapy, future devices must allow for the sequential use of the flushing chamber to promote a pre-administration patency assessment and a post-administration device flush.info:eu-repo/semantics/publishedVersio

Alluvial xenotime and heavy minerals assemblage from the northern edge of Nisa-Albuquerque Batholith, eastern Portugal : provenance and geochemical implications

Alluvial xenotime and heavy minerals assemblage from the northern edge of Nisa-Albuquerque Batholith, eastern Portugal : provenance and geochemical implications / Rute Salgueiro... [et al.]. - Amsterdam : Elsevier, 2014. - [18] p. : il., 13 figuras e 8 tabelas ; 30 cm The xenotime-bearing heavy mineral assemblages present in the alluvial samples from Vila Velha de Ródão, Nisa, Póvoa e Meadas and Sto. António das Areias, localized in the northern edge of Nisa-Albuquerque Batholith, Eastern Portugal, were studied in detail. The insights for mineral provenance came from the analysis of the drainage network and from the composition of the regional alluvial samples and outcropping lithologies. Since xenotime is a mineral with economic interest, the motivation of the current work is its contribution for exploration studies, considering the potential information contained in the alluvial samples. In the study region, the alluvial heavy minerals and their morphology reflect clearly the mineralogy and relative distance to their source, respectively. In alluvial samples with direct provenance from the Nisa granite (late Carboniferous), the increase in xenotime concentration and decrease in monazite, apatite, zircon, ilmenite and iron oxide concentration, from W (Nisa) to E (Sto. António das Areias), matches the increase in P2O5 and decrease in REE, CaO, Zr, TiO2, and Fe2O3 contents in granite rocks. The geochemical signature of xenotime studied reveals an igneous source, characterized by the characteristic strong Eu negative anomaly in REE patterns. Their YPO4 values (72–78 mol%) are similar to xenotime from Erzgebirge (Germany) granites. The high values of Y/Ho (50–71) and, in some cases, downward kinks at Ho in REE plots, suggest generation in late stages of crystallization and association with a siliceous evolved magmatic system. The slight decrease in HREE contents in xenotime, from W to E, and Ho anomalies in the normalized REE pattern are similar to those identified in the Nisa granite, which supports the sourcing of xenotime from these granitic rocks. The genetic development of the batholith chemical zonation (more evolved to E) seems to have favoured the generation of xenotime instead of apatite, monazite and zircon, in the eastern end area (Sto. António das Areias). Supporting the geochemical signature, the alluvial zircons also display morphological typologies that are compatible with provenance from peraluminous granites formed at temperatures of 600–700 °C, possibly from the Nisa granite. Since all xenotime grains show the same magmatic affinity, this leads to the hypothesis that the xenotime from the Vila Velha de Ródão sample, with provenance from Cenozoic sedimentary rocks, has been transported to this northern area, after been disaggregated from Nisa batholith granites, most probably by braided anastomosing and erratically sandy channels, that explains its actual position in the opposite bank of the Tagus river. This phosphate has been deposited with other sediments in tectonic depressions and subsequently included in the formation of sedimentary rocks. The greater development of Ca, Th and U phosphate inclusions/substitutions in these xenotime grains can be explained by the chemical mobility provided during all the geological processes

Papéis de liderança de Quinn: um estudo realizado em serviços de saúde portugueses com recurso à análise factorial confirmatória

Purpose: To assess the psychometric properties of Quinn’s leadership questionnaire (CFV questionnaire; 1988) in Portuguese health services. Design: Cross-sectional study, using Quinn’s leadership questionnaire, administered to registered nurses and physicians in Portuguese health services (N = 687). Method: Self-administered survey applied to two samples. In the first sample (convenience; N = 249 Portuguese health professionals), exploratory factor and reliability analyses were performed to the CFV questionnaire. In the second sample (stratified; N = 50 surgical units of 33 Portuguese hospitals), confirmatory factor analyses were performed using LISREL 8.80. Findings: In the first sample, an eight-factor solution emerged accounting for 65.46% of the total variance, in an interpretable factor structure (loadings> .50), with Cronbach’s ? greater than .79. This factor structure, replicated in the second sample, showed reasonable goodness-of-fit of the model to each of the leadership roles, that is, to the eight quadrants and global model. Overall, the models showed nomological validity, with scores between good and acceptable (.235 < x2/df < 2.055 and .00 < RMSEA < .077). Conclusions: Quinn’s leadership questionnaire showed good reliability and validity for the eight leadership roles, proving to be suitable for use in health care/hospital settings.info:eu-repo/semantics/publishedVersio

Presence of Gardnerella vaginalis in healthy portuguese women: a pilot study

Bacterial vaginosis (BV) has an important position worldwide, as the leading vaginal disorder in women, and affects 30-50% of African women and 10-20% of White women of reproductive age. This condition although not mortal causes great discomfort and may lead to other complications such as pre-term labour or increase susceptibility for HIV infection. During BV occur a decrease of Lactobacillus spp. present in the vaginal epithelium and an increase in the number of anaerobic microorganisms like Gardnerella vaginalis, Pretovella spp., Mobilincus spp.; Mycoplasma hominis and Atopobium vaginae. Gardnerella vaginalis is also responsible for the formation of a biofilm in the vaginal epithelium in sick women’s. However, the direct correlation between the pathology and the causing agent (or agents) has not been clearly established. Currently there is only one article in PubMed (Guerreiro et. al, 1998) referring to the prevalence of bacterial vaginosis in Portugal and we aim to extend the research in this field specifically to the portuguese population. As part of this effort one of our aims it to characterise the bacterial population of portuguese women both healthy and diagnosed with BV. As such we collected swab samples of vaginal fluids from protuguese women with the help of health professionals and using self collection. The swabs were collected and treated within 24 hours at the University of Minho for the characterization of the bacterial population present, by using conventional microbiological growth techniques, PNA-FISH microscopy and 16S PCR. It was found that about 20% of the samples tested possessed G. vaginalis and all possessed Lactobacillus spp. using all 3 identification techniques described. This result is consistent with previous reports of G. vaginalis prevalence althought slightly lower, and shows that traditional microbiological techniques, microscopy and molecular methods were consistent in terms of results

Continuous Infusion of Piperacillin/Tazobactam in Septic Critically Ill Patients - a Multicenter Propensity Matched Analysis

The clinical efficacy of continuous infusion of piperacillin/tazobactam in critically ill patients with microbiologically documented infections is currently unknown. We conducted a retrospective multicenter cohort study in 7 Portuguese intensive care units (ICU). We included 569 critically ill adult patients with a documented infection and treated with piperacillin/tazobactam admitted to one of the participating ICU between 2006 and 2010. We successfully matched 173 pairs of patients according to whether they received continuous or conventional intermittent dosing of piperacillin/tazobactam, using a propensity score to adjust for confounding variables. The majority of patients received 16g/day of piperacillin plus 2g/day of tazobactam. The 28-day mortality rate was 28.3% in both groups (p = 1.0). The ICU and in-hospital mortality were also similar either in those receiving continuous infusion or intermittent dosing (23.7% vs. 20.2%, p = 0.512 and 41.6% vs. 40.5%, p = 0.913, respectively). In the subgroup of patients with a Simplified Acute Physiology Score (SAPS) II>42, the 28-day mortality rate was lower in the continuous infusion group (31.4% vs. 35.2%) although not reaching significance (p = 0.66). We concluded that the clinical efficacy of piperacillin/tazobactam in this heterogeneous group of critically ill patients infected with susceptible bacteria was independent of its mode of administration, either continuous infusion or intermittent dosing

Evidence-informed development of a bundle for peripheral intravenous catheterization in Portugal: a delphi consensus study

Contrary to many international settings, there are no clinical guidelines for peripheral intravenous catheter (PIVC) insertion and maintenance in Portugal. We sought to derive an international consensus on a PIVC bundle that could guide Portuguese nurses’ clinical decision-making in this scope. Methods: Two international vascular access specialist groups participated in an online Delphi panel. During the first round, specialists (n = 7) were sent a summary report from a previous observational study conducted in a surgical ward in Portugal. Based on the report findings, specialists were asked to provide five to eight PIVC insertion and maintenance interventions. Then, another set of specialists (n = 7) scored and revised the recommendations until a consensus was reached (≥70% agreement). The PIVC bundle was made available and discussed with the surgical ward’s nurses. Results: After three rounds, a consensus was achieved for five evidence-informed interventions: (i) involve the person and assess the peripheral venous network; (ii) maintain an aseptic no-touch technique; (iii) ensure proper catheter dressing and fixation; (iv) perform catheter flush & lock; (v) test the peripheral venous catheter’s functionality and performance at each shift. Conclusion: The final version of the PIVC bundle achieved consensus among international experts. Despite the positive feedback provided by the ward nurses, future studies are warranted to assess its effectiveness in standardizing PIVC care delivery and its potential implications for care outcomes in Portuguese clinical settings.info:eu-repo/semantics/publishedVersio

Correlação geológica das sequências da Mina de Neves-Corvo e do Pomarão (Faixa Piritosa Ibérica, Portugal)

ABSTRACT: A geological correlation between Neves-Corvo (NC) and Pomarão antiforms is attempted. These regional scale major sequences are easily correlated but, at local scale, facies and age differences stand out. Stratigraphy includes: i) the Phyllite-Quartzite Group with identical paleogeography setting and similar late Famennian ages for uppermost levels (LL to LN miospore biozones in Pomarão and NC respectively). ii) the Volcano-Sedimentary Complex shows some discrepancy concerning the age distribution of the felsic volcanic rocks (ca. 356-330 for Pomarão and ca. 365-346 Ma for all NC area) while sediments range from mid-Famennian to late Visean age (VH to NM Miospore Biozone for NC). iii); the Baixo Alentejo Flysch Group (late Visean NM Miospore Biozone onwards in NC), covering the previous sequences and being slightly older than the uppermost volcanic rocks of Pomarão. The correlation between these two structures is supported by geology and isotopic/biozone ages and favours exploration scenarios in both regions.RESUMO: Neste trabalho é discutida a correlação estratigráfica de duas estruturas antiforma marcantes da Faixa Piritosa Ibérica (FPI). Por um lado, a região mineira de Neves-Corvo (NC), a maior mina de sulfuretos maciços vulcanogénicos da Europa, intensamente estudada e, por outro, o setor ocidental da estrutura Pomarão-Puebla de Guzmán-Tharsis, uma das mais importantes e completas secções geológicas cartografadas na província. A sequência estratigráfica completa da FPI está representada nos dois setores, nomeadamente, o Grupo Filito-Quartzítico (PQ), seguindo-se o Complexo Vulcano-Sedimentar (CVS) e o Grupo do Flysch do Baixo Alentejo. À escala local, existe maior variabilidade em termos de fácies litológicas, características petrográficas e de idade. O PQ apresenta base de idade desconhecida, sendo compreendido entre o Givetiano médio (Biozona TA) e o Famenniano superior (Biozona LN, Estruniano). O topo é marcado pela presença de níveis de calcários nos dois locais, com idades aproximadas. No CVS observa-se maior variabilidade de idades, nomeadamente ca. 356-330 Ma no Pomarão e ca. 365-346 Ma para toda a área de NC. Na sua base, predominam essencialmente as fácies de xistos negros (Biozonas de Esporos VH a LN), rochas vulcânicas félsicas interdigitadas e sulfuretos maciços, no caso de NC. A sequência sobrejacente do CVS, inclui unidades de xistos siliciosos com nódulos de diferente composição (Biozona de Esporos NM, Viseano médio) e rochas vulcânicas e vulcanogénicas com um espectro de idades com alguma heterogeneidade. Entre este setor e a secção superior do Complexo existe um nível guia, à escala da província, representado por Xistos Borra de Vinho, também presente nas duas áreas de estudo. Acima deste nível ocorrem sedimentos vulcanogénicos e siliciosos de idade Viseano sup. (Biozona de Esporos NM assinalada em NC) e ca. 330 Ma (em níveis vulcânicos no Pomarão). No topo da sequência, há uma transição das unidades do CVS para os turbiditos da Fm. de Mértola (Viseano sup., Biozona de Esporos NM). Salienta-se o facto das idades da base desta formação flysch serem em NC um pouco mais antigas que o topo do CVS no Pomarão. Deste estudo, enfatiza-se uma maior homogeneidade ao nível das formações sedimentares entre as sequências das duas regiões, comparativamente com as intercalações de origem vulcânica, com carácter mais local e maior variabilidade de fácies. A correlação entre as duas estruturas permite identificar cenários favoráveis à prospeção mineral.info:eu-repo/semantics/publishedVersio