491 research outputs found

    A new vehicle for herbicide application using crude glycerin, a by-product of biodiesel production

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    The supply of glycerin derived from the pre-purification of biodiesel has increased considerably in Brazil, making it necessary to identify economic and environmentally friendly applications for this byproduct. This work aimed to develop oil-in-water (O/W) emulsions using crude glycerin treated with H3PO4 for use as a vehicle for the application the herbicide Togar. The work was conducted in the laboratory of Marlebologia at the Federal University of Tocantins, Gurupi Campus. The preliminary emulsions were subjected to stability testing, and those that remained stable were diluted with the herbicide Togar (8% v v-1) and characterized with respect to pH, conductivity, viscosity, density and surface tension. The crude glycerin was used to develop five stable emulsions with promising physicochemical characteristics for use as vehicle for herbicide application. The conductivity and viscosity of the emulsions were high compared to diesel.Key words: Agrochemicals, residue, emulsions

    Casbane diterpene as a promising natural antimicrobial agent against biofilm-associated infections

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    Croton nepetaefolius is a native plant from northeastern Brazil that belongs to the Euphorbiaceae family. The biological action of this plant has been extensively explored, being the secondary metabolites responsible for its properties alkaloids, diterpenes, and triterpenes. This study aimed to evaluate the ability of casbane diterpene (CD), isolated from the ethanolic extract of C. nepetaefolius, to inhibit microbial growth and biofilm formation of several clinical relevant species (bacteria and yeasts). It was found that CD possessed biocidal and biostatic activity against the majority of the species screened, with minimal active concentrations ranging between 125 and 500 µg/mL. In addition, it was observed that biofilm formation was inhibited even when the planktonic growth was not significantly affected. In conclusion, CD showed potential to be a natural tool for the treatment of diseases caused by different infectious microorganismsThis study was supported by FUNCAP and CNPq (Brazil) and by FCT (Portugal) through the project PTDC/SAU-ESA/64609/2006

    Cyclophosphamide- metabolizing enzyme polymorphisms and survival outcomes after adjuvant chemotherapy for node-positive breast cancer: a retrospective cohort study

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    Abstract Introduction Cyclophosphamide-based adjuvant chemotherapy is a mainstay of treatment for women with node-positive breast cancer, but is not universally effective in preventing recurrence. Pharmacogenetic variability in drug metabolism is one possible mechanism of treatment failure. We hypothesize that functional single nucleotide polymorphisms (SNPs) in drug metabolizing enzymes (DMEs) that activate (CYPs) or metabolize (GSTs) cyclophosphamide account for some of the observed variability in disease outcomes. Methods We performed a retrospective cohort study of 350 women enrolled in a multicenter, randomized, adjuvant breast cancer chemotherapy trial (ECOG-2190/INT-0121). Subjects in this trial received standard-dose cyclophosphamide, doxorubicin and fluorouracil (CAF), followed by either observation or high-dose cyclophosphamide and thiotepa with stem cell rescue. We used bone marrow stem cell-derived genomic DNA from archival specimens to genotype CYP2B6, CYP2C9, CYP2D6, CYP3A4, CYP3A5, GSTM1, GSTT1, and GSTP1. Cox regression models were computed to determine associations between genotypes (individually or in combination) and disease-free survival (DFS) or overall survival (OS), adjusting for confounding clinical variables. Results In the full multivariable analysis, women with at least one CYP3A4 *1B variant allele had significantly worse DFS than those who were wild-type *1A/*1A (multivariate hazard ratio 2.79; 95% CI 1.52, 5.14). CYP2D6 genotype did not impact this association among patients with estrogen receptor (ER) -positive tumors scheduled to receive tamoxifen. Conclusions These data support the hypothesis that genetic variability in cyclophosphamide metabolism independently impacts outcome from adjuvant chemotherapy for breast cancer

    Short-Term Exercise Training Inconsistently Influences Basel Testosterone in Older Men: A Systematic Review and Meta-Analysis

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    Background The age-associated decrease in testosterone is one mechanism suggested to accelerate the aging process in males. Therefore, approaches to increase endogenous testosterone may be of benefit. The aim of this paper was to undertake a Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA)-accordant meta-analysis concerning the effect of exercise on total (TT), bioavailable (bio-T), free (free-T), and salivary (sal-T) testosterone in older males. Methods Databases were searched up to and including 20th February 2018 for the terms ‘testosterone AND exercise AND aging AND males’, ‘testosterone AND exercise AND old AND males’, ‘testosterone AND training AND aging AND males’ and ‘testosterone AND training AND old AND males’. From 1259 originally identified titles, 22 studies (randomized controlled trials; RCTs; n=9, and uncontrolled trials; UCTs; n=13) were included which had a training component, participants ≥60 years of age, and salivary or serum testosterone as an outcome measure. Meta-analyses were conducted on change to testosterone following training using standardised difference in means (SDM) and random effects models. Results The overall SDM for endurance training, resistance training, and interval training was 0.398 (95% CI = 0.034 – 0.761; P = 0.010), -0.003 (95% CI = -0.330 – 0.324; P = 0.986), and 0.283 (95% CI = 0.030 – 0.535; P = 0.028) respectively. Resistance training exhibited a qualitative effect of hormone fraction whereby free-T resulted in the greatest SDM (0.253; 95% CI = -0.043 – 0.549; P = 0.094), followed by TT (0.028; 95% CI = -0.204 – 0.260; P = 0.813), and resistance training negatively influenced bio-T (-0.373; 95% CI = -0.789 – 0.042; P = 0.078). Due to the small number of studies, subgroup analysis was not possible for endurance training and interval training studies. Conclusions Data from the present investigation suggests that resistance training does not significantly influence basal testosterone in older men. Magnitude of effect was influenced by hormone fraction, even within the same investigation. Aerobic training and interval training did result in small, significant increases in basal testosterone. The magnitude of effect is small but the existing data are encouraging and may be an avenue for further research

    Detection of Human Bocavirus mRNA in Respiratory Secretions Correlates with High Viral Load and Concurrent Diarrhea

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    Human bocavirus (HBoV) is a parvovirus recently identified in association with acute respiratory infections (ARI). Despite its worldwide occurrence, little is known on the pathogenesis of HBoV infections. In addition, few systematic studies of HBoV in ARI have been conducted in Latin America. Therefore, in order to test whether active viral replication of human bocavirus is associated with respiratory diseases and to understand the clinical impact of this virus in patients with these diseases, we performed a 3-year retrospective hospital-based study of HBoV in outpatients and inpatients with symptoms of Acute Respiratory Infections (ARI) in Brazil. Nasopharyngeal aspirates (NPAs) from 1015 patients with respiratory symptoms were tested for HBoV DNA by PCR. All samples positive for HBoV were tested by PCR for all other respiratory viruses, had HBoV viral loads determined by quantitative real time PCR and, when possible, were tested by RT-PCR for HBoV VP1 mRNA, as evidence of active viral replication. HBoV was detected in 4.8% of patients, with annual rates of 10.0%, 3.0% and 3.0% in 2005, 2006 and 2007, respectively. The range of respiratory symptoms was similar between HBoV-positive and HBoV-negative ARI patients. However, a higher rate of diarrhea was observed in HBoV-positive patients. High HBoV viral loads (>108 copies/mL) and diarrhea were significantly more frequent in patients with exclusive infection by HBoV and in patients with detection of HBoV VP1 mRNA than in patients with viral co-infection, detected in 72.9% of patients with HBoV. In summary, our data demonstrated that active HBoV replication was detected in a small percentage of patients with ARI and was correlated with concurrent diarrhea and lack of other viral co-infections

    Noninvasive Assessment of Coronary Artery Disease in Women: What’s Next?

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    Significant progress in research has been made in the areas of sex-specific aspects of cardiovascular disease. Despite these advances, coronary artery disease (CAD) is the leading cause of death of women in the Western world. Over the past decade, the focused research on women at risk for ischemic heart disease has helped to clarify our understanding of some of the sex-specific factors, which are important in detecting CAD. In women, the detection and evaluation of physiologically significant CAD is challenging, especially given that traditional tests designed to detect focal areas of coronary artery stenosis are less sensitive and specific in female patients who have a lower prevalence of obstructive coronary disease, greater burden of symptoms, and a high atherosclerotic burden. In this article, we review the available evidence on the role of contemporary cardiovascular imaging techniques in evaluating ischemic heart disease in women

    Temperature-dependent mechanical behaviour of PMMA: Experimental analysis and modelling

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    This paper was published in the journal Polymer Testing and the definitive published version is available at http://dx.doi.org/10.1016/j.polymertesting.2016.12.016.© 2016 Elsevier LtdAn experimental study of temperature-dependent mechanical behaviour of Poly-methyl methacrylate (PMMA) was performed at a range of temperatures (20 °C, 40 °C, 60 °C and 80 °C) below its glass transition point (108 °C) under uniaxial tension and three-point bending loading conditions. This study was accompanied by simulations aimed at identification of material parameters for two different constitutive material models. Experimental flow curves obtained for PMMA were used in elasto-plastic analysis, while a sim-flow optimization tool was employed for a two-layer viscoplasticity model. The temperature increase significantly affected mechanical behaviour of PMMA, with quasi-brittle fracture at room temperature and super-plastic behaviour (ε>110%) at 80 °C. The two-layer viscoplasticity material model was found to agree better with the experimental data obtained for uniaxial tension than the elasto-plastic description
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