Bioactivities from marine algae of the genus Gracilaria de Almeida, Cynthia Layse F; Falcão, Heloina de S; Lima, Gedson R de M ...
International Journal of Molecular Sciences,
07/2011, Letnik:
12, Številka:
7
Journal Article, Book Review
Recenzirano
Odprti dostop
Seaweeds are an important source of bioactive metabolites for the pharmaceutical industry in drug development. Many of these compounds are used to treat diseases like cancer, acquired ...immune-deficiency syndrome (AIDS), inflammation, pain, arthritis, as well as viral, bacterial, and fungal infections. This paper offers a survey of the literature for Gracilaria algae extracts with biological activity, and identifies avenues for future research. Nineteen species of this genus that were tested for antibacterial, antiviral, antifungal, antihypertensive, cytotoxic, spermicidal, embriotoxic, and anti-inflammatory activities are cited from the 121 references consulted.
Aim
To assess the effect of immersion in distilled water or phosphate‐buffered saline (PBS) on the solubility, volumetric change and presence of voids of calcium silicate‐based root canal sealers ...(TotalFill BC, Sealer Plus BC and Bio‐C), in comparison with the gold standard epoxy resin‐based sealer (AH Plus).
Methodology
All properties were evaluated after immersion in distilled water or PBS. Solubility was determined by the percentage of mass loss, whereas volumetric change and presence of voids were evaluated by micro‐computed tomography, after 7 days of immersion. The volumetric change and percentage of voids between the baseline (after setting) and the experimental period were calculated. Statistical analysis was performed using one‐way anova and Tukey's or Student's t‐tests (α = 0.05).
Results
The calcium silicate‐based sealers had significantly greater solubility and volumetric loss than AH Plus, after immersion in distilled water or PBS (P < 0.05). Bio‐C had the greatest solubility (P < 0.05), followed by TotalFill BC and Sealer Plus BC, which were similar (P > 0.05). Regarding the volumetric change, AH Plus had a volume increase, with similar values in distilled water and PBS (P > 0.05). TotalFill BC, Sealer Plus BC and Bio‐C had a similar volumetric change (P > 0.05). The calcium silicate‐based materials had the greatest solubility and volume loss after immersion in distilled water (P < 0.05). There was no difference in the percentage of voids amongst the sealers, before and after immersion in distilled water or PBS (P > 0.05).
Conclusions
TotalFill BC, Sealer Plus BC and Bio‐C had significantly greater solubility and volumetric loss than AH Plus. Although storage in PBS significantly reduced the solubility and volumetric change of calcium silicate‐based sealers, their solubility remained above that recommend by ISO 6876. All the sealers evaluated had low and similar voids, even after immersion in distilled water or PBS.
Aim
To analyse the antimicrobial and biological properties of a new bioceramic intracanal medicament (Bio‐C Temp), and to compare it with two calcium hydroxide‐based intracanal medicaments (Calen® ...and UltraCal® XS).
Methodology
The direct contact and the crystal violet tests were performed to assess the antimicrobial activity of intracanal medicaments against Enterococcus faecalis. The cytocompatibility and the effect of the medication on the biology of the human osteoblast‐like cell line (Saos‐2) were evaluated with methylthiazole tetrazolium (MTT), neutral red, alkaline phosphatase activity and mineralization (alizarin red) assays. The data were analysed using one‐way anova and Tukey’s tests, two‐way anova and Bonferroni’s tests, or Kruskal–Wallis and Dunn’s tests (α = 0.05).
Results
Bio‐C Temp had significantly less antibacterial activity and biofilm biomass reduction than the other intracanal medicaments (P < 0.05). There was no difference in the viability of Saos‐2 exposed to the various intracanal medicaments, except regarding the 1 : 2 dilution, when the Bio‐C Temp group had significantly lower cell viability than the UltraCal® XS and Calen® groups (P < 0.05). Bio‐C Temp induced significantly greater ALP activity than the other intracanal medicaments (P < 0.05) at day 1. Calen® induced significantly greater deposition of mineralized nodules than the other intracanal medicaments (P < 0.05), and no difference was observed between Bio‐C Temp and UltraCal® XS (P > 0.05).
Conclusions
Bio‐C Temp had similar cytocompatibility at higher dilutions, and higher or similar induction of ALP activity and deposition of mineralized nodules in comparison with Calen® and UltraCal® XS. However, it had significantly less antibacterial and antibiofilm activity than Calen® and UltraCal® XS.
Studies on environmental consequences of stress on animal production have grown substantially in the last few years for economic and animal welfare reasons. Physiological, hormonal, and immunological ...deficits as well as increases in animals' susceptibility to diseases have been reported after different stressors in broiler chickens. The aim of the current experiment is to describe the effects of 2 different heat stressors (31 ± 1 and 36 ± 1°C/10 h per d) applied to broiler chickens from d 35 to 42 of life on the corticosterone serum levels, performance parameters, intestinal histology, and peritoneal macrophage activity, correlating and discussing the obtained data under a neuroimmune perspective. In our study, we demonstrated that heat stress (31 ± 1 and 36 ± 1°C) increased the corticosterone serum levels and decreased BW gain and food intake. Only chickens submitted to 36 ± 1°C, however, presented a decrease in feed conversion and increased mortality. We also showed a decrease of bursa of Fabricius (31 ± 1 and 36 ± 1°C), thymus (36 ± 1°C), and spleen (36 ± 1°C) relative weights and of macrophage basal (31 ± 1 and 36 ± 1°C) and Staphylococcus aureus-induced oxidative burst (31 ± 1°C). Finally, mild multifocal acute enteritis characterized by an increased presence of lymphocytes and plasmocytes within the jejunum's lamina propria was also observed. The stress-induced hypothalamic-pituitary-adrenal axis activation was taken as responsible for the negative effects observed on the chickens' performance and immune function and also the changes of the intestinal mucosa. The present obtained data corroborate with others in the field of neuroimmunomodulation and open new avenues for the improvement of broiler chicken welfare and production performance.
The higher heating value (HHV) is an important parameter to indicate the energetic potential of biomass from different sources. Bomb calorimeter is the standard to obtain this data; however, in the ...absence of this equipment, estimative through proximate analysis aided with multiple regression formulas is an acceptable alternative. Still, this is a time-consuming technique and highly dependable of operator skills. In this context, thermogravimetric analysis has been used to obtain proximate analysis results with higher precision and demanding a small amount of samples. Here, a simple and effective method to estimate HHV from data obtained by thermogravimetric analysis using different sources of biomass is presented. The proposed method showed to be more accurate to estimate HHV than proximate analysis laboratory procedure. Greater correlation was observed between the HHV values obtained from calorimeter–thermogravimetry than the ones obtained from calorimeter–proximate analysis. Multiple regression analysis indicated that fixed carbon and ashes have an inverse influence over HHV, while the former is responsible for high calorific value and the latter affects energy release. Finally, the proposed method showed to be fast and accurate to estimate HHV of biochar samples and should be easily adaptable to other studies that require fast assessment of calorific value from biochar.
The art of estimating future values of a random process, based upon previously observed or estimated values, is usually known as a priori estimation, prediction, or forecasting. Power system state ...estimation process can be enhanced if state/measurement forecasts are incorporated into it. Important research efforts have been made in this direction bringing a fresh perspective to the state estimation problem. This paper (Part I) presents a comprehensive survey of forecasting-aided state estimators. It gathers up-covering a period of three decades-research results on the main benefits achieved by state estimators with forecasting capability regarding: data redundancy, innovation analysis, observability, filtering, bad data, and network configuration and parameter error processing. Aspects of modeling, forecasting techniques, and computational effort are also addressed. The second of this two-paper series presents the results of the implementation of a forecasting-aided state estimator in the energy management system of the LIGHT Services of Electricity, a company which provides electric energy to Rio de Janeiro, Brazil.
Rhodoliths are nodules of non-geniculate coralline algae that occur in shallow waters (<150 m depth) subjected to episodic disturbance. Rhodolith beds stand with kelp beds, seagrass meadows, and ...coralline algal reefs as one of the world's four largest macrophyte-dominated benthic communities. Geographic distribution of rhodolith beds is discontinuous, with large concentrations off Japan, Australia and the Gulf of California, as well as in the Mediterranean, North Atlantic, eastern Caribbean and Brazil. Although there are major gaps in terms of seabed habitat mapping, the largest rhodolith beds are purported to occur off Brazil, where these communities are recorded across a wide latitudinal range (2°N-27°S). To quantify their extent, we carried out an inter-reefal seabed habitat survey on the Abrolhos Shelf (16°50'-19°45'S) off eastern Brazil, and confirmed the most expansive and contiguous rhodolith bed in the world, covering about 20,900 km(2). Distribution, extent, composition and structure of this bed were assessed with side scan sonar, remotely operated vehicles, and SCUBA. The mean rate of CaCO(3) production was estimated from in situ growth assays at 1.07 kg m(-2) yr(-1), with a total production rate of 0.025 Gt yr(-1), comparable to those of the world's largest biogenic CaCO(3) deposits. These gigantic rhodolith beds, of areal extent equivalent to the Great Barrier Reef, Australia, are a critical, yet poorly understood component of the tropical South Atlantic Ocean. Based on the relatively high vulnerability of coralline algae to ocean acidification, these beds are likely to experience a profound restructuring in the coming decades.
We report strong evidence of the importance of contact hubs (or superspreaders) in mitigating the current COVID-19 pandemic. Contact hubs have a much larger number of contacts than the average in the ...population, and play a key role on the effectiveness of vaccination strategies. By using an age-structures compartmental SEIAHRV (Susceptible, Exposed, Infected symptomatic, Asymptomatic, Hospitalized, Recovered, Vaccinated) model, calibrated from available demographic and COVID-19 incidence, and considering separately those individuals with a much greater number of contacts than the average in the population, we show that carefully choosing who will compose the first group to be vaccinated can impact positively the total death toll and the demand for health services. This is even more relevant in countries with a lack of basic resources for proper vaccination and a significant reduction in social isolation. In order to demonstrate our approach we show the effect of hypothetical vaccination scenarios in two countries of very different scales and mitigation policies, Brazil and Portugal.
The prospect of growth of a railway system impacts both the network size and its occupation. Due to the overloaded infrastructure, it is necessary to increase reliability by adopting fast maintenance ...services to reach economic and security conditions. In this context, one major problem is the excessive friction caused by the wheels. This contingency may cause ruptures with severe consequences. While eddy’s current approaches are adequate to detect superficial damages in metal structures, there are still open challenges concerning automatic identification of rail defects. Herein, we propose an embedded system for online detection and location of rails defects based on eddy current. Moreover, we propose a new method to interpret eddy current signals by analyzing their wavelet transforms through a convolutional neural network. With this approach, the embedded system locates and classifies different types of anomalies, enabling an optimization of the railway maintenance plan. Field tests were performed, in which the rail anomalies were grouped in three classes: squids, weld and joints. The results showed a classification efficiency of ~98%, surpassing the most commonly used methods found in the literature.
The hydrological effects of forest cover loss are difficult to discern in the case of large‐scale basins with gradual changes and difficult to isolate when climate variability is also present. In the ...present study, we evaluated the effects of climate variability and human activity on the annual streamflow in a basin in the Amazon arc of deforestation. We statistically analyzed the components of the annual water balance and monthly streamflow and used the currently used Tomer‐Schilling, elasticity, and decomposition of Budyko‐type curve methods to separate climate‐induced changes and anthropogenic effects. Annual series of the monthly maximum and minimum streamflow, total streamflow, and total reference evapotranspiration presented statistically significant increasing trends. No significant trend was observed for precipitation. The greatest change in the average annual runoff coefficient was observed between the first (1973–1984) and second (1985–1994) analyzed periods. Even with the continuous reduction in the forested area, the third (1994–2004) and fourth analyzed periods (2003–2016) showed only relatively small changes, most likely due to the intensity of slash‐and‐burn activities and vegetation regrowth. The methods showed that deforestation was the primary cause of the streamflow changes, but with different intensities, and a small recuperation was observed in the last analyzed period. On average, the annual water yield would increase between 26% and 58% after the first time interval without the opposite effect of climate variability, which must be considered in basin management. Future research should focus on analyzing the water storage and the dependence of the precipitation‐runoff relationship from the climate.
Plain Language Summary
The effects of deforestation on water availability are difficult to discern in the case of large river basins and when there are also changes in the climate. We evaluated the effects of both, climate variability and human activities, on the annual average river flow in a water basin situated in the most deforested region of the Amazon biome. Statistical analyzes showed that there were significant increases in the average annual flow of the river and in the annual reference evapotranspiration (determined by the climate) during the years after the beginning of deforestation in the region, but not in precipitation. The greatest change in the percentage of precipitation that turns into streamflow was observed between the first (1973–1984) and second (1985–1994) analyzed periods. Even with the continuous of deforestation in the basin, the other periods (1994–2004 and 2003–2016) showed only relatively small changes, most likely due to vegetation regrowth. Three different methods showed that deforestation was the primary cause of the streamflow change, but annual streamflow would be between 26% and 58% greater without the opposite effect of climate. These results must be considered in the management of water resources in the region.
Key Points
Comparison of three methods to separate land use and climate‐induced effects on streamflow in the Itacaiúnas River basin was shown
We analyze that the intensity of slash‐and‐burn activities and vegetation regrowth, in addition to forested area, can help to explain the results
The methods show that deforestation is the primary cause of streamflow changes, but with different intensities
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