2,326 research outputs found
Biodegradability of diesel and biodiesel blends
The biodegradability of pure diesel and biodiesel and blends with different proportions of biodiesel (2%(commercial); 5% and 20%) was evaluated employing the respirometric method and the redox indicator2,6-dichlorophenol indophenol (DCPIP) test. In the former, experiments simulating the contamination of natural environments (soil from a petrol station or water from a river) were carried out in Bartha biometer flasks (250 ml), and used to measure the microbial CO2 production. With the DCPIP test, the capability of three inocula to biodegrade the blends was tested. Results show that although biodiesel is more easily and faster biodegraded than diesel oil, among the blends evaluated (2%, 5% and 20%), only the blend with higher concentration of biodiesel presented biodegradability significantly different from diesel and it was not verified an improvement on the biodegradation of the diesel by means of cometabolism
Toxicity of copaiba extracts to armyworm (Spodoptera frugiperda)
The objective of this study was to evaluate the effects of methanolic extracts from leaves, peels, seeds and pulps from fruits of Copaifera langsdorffii on Spodoptera frugiperda. Extracts derived from leaves and fruit peels were more toxic to S. frugiperda than the others. Hence, they were added to the artificial diet and used in further experiments with the second instar larvae of the insect, which presented larval growth reduction, prolonged period of development, increased mortality, and lower fertility and fecundity of adults. Lower egg viability was also observed when the insect was treated with extracts of leaves and fruit peels in the larvae stage. Moreover, when subjected to ultrastructural analysis under a scanning electron microscope, such eggs showed abnormalities in the aeropylar and micropylar regions. Both extracts also increased the excretion of protein in the insect feces and inhibited trypsin activity in the in vitro test. Consequently, C. langsdorffii presents potential to be used in the development of new products to control the fall armyworm.Key words: Copaifera langsdorffii, natural products, trypsin inhibitor, botanical insecticide
Simulations of extensional flow in microrheometric devices
We present a detailed numerical study of the flow of a Newtonian fluid through microrheometric devices featuring a sudden contraction–expansion. This flow configuration is typically used to generate extensional deformations and high strain rates. The excess pressure drop resulting from the converging and diverging flow is an important dynamic measure to quantify if the device is intended to be used as a microfluidic extensional rheometer. To explore this idea, we examine the effect of the contraction length, aspect ratio and Reynolds number on the flow kinematics and resulting pressure field. Analysis of the computed velocity and pressure fields show that, for typical experimental conditions used in microfluidic devices, the steady flow is highly three-dimensional with open spiraling vortical structures in the stagnant corner regions. The numerical simulations of the local kinematics and global pressure drop are in good agreement with experimental results. The device aspect ratio is shown to have a strong impact on the flow and consequently on the excess pressure drop, which is quantified in terms of the dimensionless Couette and Bagley correction factors. We suggest an approach for calculating the Bagley correction which may be especially appropriate for planar microchannels
Hyperoside Supplementation in Preservation Media Surpasses Vitamin C Protection Against Oxidative Stress-Induced Damages in Human Spermatozoa
Background/Aims: Oxidative Stress (OS) is reported as one of the main causes of male infertility. Infertile couples often resort to assisted reproductive technology (ART) to achieve parenthood. However, preparation for ART protocols increases the exposer of gametes to OS. Thus, it is crucial to find suitable preservation media that can counteract the OS-induced damages in spermatozoa. In this work, we tested and compared the efficiency of vitamin C (VC) and hyperoside (HYP) as potential antioxidant supplements for sperm preservation media. Methods: We evaluated the cytotoxicity of HYP (0, 5, 50, 100, and 500 µM) in spermatozoa. After incubation of sperm cells with VC (600 µM) and HYP (100 and 500 µM), in the presence and absence of H2O2 (300 µM), the following parameters were assessed: total sperm motility and vitality, OS biomarkers expression, total antioxidant capacity (TAC) of the media, percentage of DNA fragmentation, mitochondrial membrane potential (MMP), and metabolite quantification of the media by proton nuclear magnetic resonance (1H-NMR). Results: The supplementation with VC (600 µM) and HYP (100 and 500 µM) did not induce any deleterious effects to the physiology and metabolism of the spermatozoa, after 1-hour of treatment. In the presence of H2O2 (300 µM), both VC and HYP were able to prevent some of the deleterious effects of H2O2 in sperm, which were represented by an increase in sperm motility, a decrease in DNA fragmentation, and a decreasing trend in lipid peroxidation levels. However, these antioxidants were not able to prevent the decrease of MMP associated with H2O2 treatment, nor were able to prevent the conversion of pyruvate into acetate (a reaction promoted by H2O2). Conclusion: The supplementation of sperm preservation media with VC and HYP could be beneficial for the preservation of sperm physiology. From the antioxidant conditions tested, the supplementation of media with HYP (100 µM) demonstrated the best results regarding sperm preservation, evidencing the higher antioxidant capacity of HYP compared to VC. Nevertheless, none of the antioxidants used was able to prevent the metabolic alterations promoted by H2O2 in spermatozoa.This work was supported by Fundação para a Ciência e a Tecnologia - FCT to Sara C. Pereira (2021.05487.BD); David F. Carrageta (SFRH/BD/136779/2018); Marco G. Alves (IFCT2015 and PTDC/MEC-AND/28691/2017); LAQV-REQUIMTE (UIDB/50006/2020); UMIB (UIDB/00215/2020, and UIDP/00215/2020); ITR - Laboratory for Integrative and Translational Research in Population Health (LA/P/0064/2020). Pedro F. Oliveira was funded by national funds through FCT – Fundação para a Ciência e a Tecnologia, I.P., under the Scientific Employment Stimulus - Institutional Call - reference CEECINST/00026/2018
Modeling the potential distribution of the invasive golden mussel Limnoperna fortunei in the Upper Paraguay River system using limnological variables
Obesity-induced hypoadiponectinaemia: the opposite influences of central and peripheral fat compartments
The substantial reduction in adiponectin concentration among obese individuals seems to depend on fat distribution and is a marker of metabolic and adipose tissue dysfunction. We aimed to: (i) address whether abdominal fat from different compartments (visceral, deep subcutaneous abdominal and superficial subcutaneous abdominal) and gluteofemoral fat are independently associated with blood adiponectin concentration; and (ii) investigate whether abdominal (proxied by waist circumference) and gluteofemoral fat (proxied by hip circumference) accumulation causally determine blood adiponectin concentration.
To investigate the independent association of abdominal and gluteofemoral fat with adiponectin concentration, we used multivariable regression and data from 30-year-old adults from the 1982 Pelotas Birth Cohort ( = 2,743). To assess the causal role of abdominal and gluteofemoral fat accumulation on adiponectin concentration, we used Mendelian randomization and data from two consortia of genome-wide association studies—the GIANT ( > 210 000) and ADIPOGen consortia ( = 29 347).
In the multivariable regression analysis, all abdominal fat depots were negatively associated with adiponectin concentration, specially visceral abdominal fat [men: = -0.24 standard unit of log adiponectin per standard unit increase in abdominal fat; 95% confidence interval (CI) = -0.31, -0.18; = 8*10; women: = -0.31; 95% CI = -0.36, -0.25; = 7*10), whereas gluteofemoral fat was positively associated with adiponectin concentration (men: = 0.13 standard unit of log adiponectin per standard unit increase in gluteofemoral fat; 95% CI = 0.03, 0.22; = 0.008; women: = 0.24; 95% CI = 0.17, 0.31; = 7*10). In the Mendelian randomization analysis, genetically-predicted waist circumference was inversely related to blood adiponectin concentration ( = -0.27 standard unit of log adiponectin per standard unit increase in waist circumference; 95% CI = -0.36, -0.19; = 2*10), whereas genetically-predicted hip circumference was positively associated with blood adiponectin concentration ( = 0.17 standard unit of log adiponectin per standard unit increase in hip circumference; 95% CI = 0.11, 0.24; = 1*10).
These results support the hypotheses that there is a complex interplay between body fat distribution and circulating adiponectin concentration, and that whereas obesity-induced hypoadiponectinaemia seems to be primarily attributed to abdominal fat accumulation, gluteofemoral fat accumulation is likely to exert a protective effect.The study ‘Pelotas Birth Cohort, 1982’ is conducted by Postgraduate Program in Epidemiology at Universidade Federal de Pelotas with the collaboration of the Brazilian Public Health Association (ABRASCO). From 2004 to 2013, the Wellcome Trust supported the 1982 birth cohort study. The International Development Research Center, World Health Organization, Overseas Development Administration, European Union, National Support Program for Centers of Excellence (PRONEX), the Brazilian National Research Council (CNPq) and the Brazilian Ministry of Health supported previous phases of the study. M.C.B. receives financial support from the Brazilian National Research Council (CNPq) [144749/2014-9, 201498/2014-6 (Science Without Borders Program), and 163291/2015-2] and Coordenac¸~ao de Aperfeic¸oamento de Pessoal de Nıvel Superior (CAPES). K.K.O. is supported by the Medical Research Council [Unit Programme numbers MC_UU_12015/1 and MC_UU_12015/2]
Uptake of oxLDL and IL-10 production by macrophages requires PAFR and CD36 recruitment into the same lipid rafts
Macrophage interaction with oxidized low-density lipoprotein (oxLDL) leads to its differentiation into foam cells and cytokine production, contributing to atherosclerosis development. In a previous study, we showed that CD36 and the receptor for platelet-activating factor (PAFR) are required for oxLDL to activate gene transcription for cytokines and CD36. Here, we investigated the localization and physical interaction of CD36 and PAFR in macrophages stimulated with oxLDL. We found that blocking CD36 or PAFR decreases oxLDL uptake and IL-10 production. OxLDL induces IL-10 mRNA expression only in HEK293T expressing both receptors (PAFR and CD36). OxLDL does not induce IL-12 production. The lipid rafts disruption by treatment with βCD reduces the oxLDL uptake and IL-10 production. OxLDL induces co-immunoprecipitation of PAFR and CD36 with the constitutive raft protein flotillin-1, and colocalization with the lipid raft-marker GM1-ganglioside. Finally, we found colocalization of PAFR and CD36 in macrophages from human atherosclerotic plaques. Our results show that oxLDL induces the recruitment of PAFR and CD36 into the same lipid rafts, which is important for oxLDL uptake and IL-10 production. This study provided new insights into how oxLDL interact with macrophages and contributing to atherosclerosis development
Stimulation of lymphocyte anti-melanoma activity by co-cultured macrophages activated by complex homeopathic medication
<p>Abstract</p> <p>Background</p> <p>Melanoma is the most aggressive form of skin cancer, and the most rapidly expanding cancer in terms of worldwide incidence. Chemotherapeutic approaches to treat melanoma have been uniformly disappointing. A Brazilian complex homeopathic medication (CHM), used as an immune modulator, has been recommended for patients with depressed immune systems. Previous studies in mice have demonstrated that the CHM activates macrophages, induces an increase in the number of leukocytes and improves the murine response against Sarcoma-180.</p> <p>Methods</p> <p>Here we studied the interaction of mouse lymph node lymphocytes, co-cultured <it>in vitro </it>with macrophages in the presence or absence of the CHM, with B16F10 melanoma cells.</p> <p>Results</p> <p>Lymphocytes co-cultured with macrophages in the presence of the CHM had greater anti-melanoma activity, reducing melanoma cell density and increasing the number of lysed tumor cells. There was also a higher proportion of activated (CD25<sup>+</sup>) lymphocytes with increased viability. Overall, lymphocytes activated by treatment destroyed growing cancer cells more effectively than control lymphocytes.</p> <p>Conclusion</p> <p>Co-culture of macrophages with lymphocytes in the presence of the CHM enhanced the anti-cancer performance of lymphocytes against a very aggressive lineage of melanoma cells. These results suggest that non-toxic therapies using CHMs are a promising alternative approach to the treatment of melanomas. In addition, they are attractive combination-therapy candidates, which may enhance the efficacy of conventional medicines by improving the immune response against tumor cells.</p
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