Environ Sci Pollut Res Int
December 2024
Biofouling in freshwater and marine environments developed on man-made aquatic surfaces causes significant economic losses. Still, this problem is magnified when it comes to invasive species, such as the golden mussel. One of the alternatives to combat it is the use of antifouling solutions; however, the vast majority focus on solutions for the marine environment.
View Article and Find Full Text PDFCarbon dioxide emissions are altering aquatic ecosystems by causing water acidification and temperature increases, and these environments are also facing pesticide contamination. We present a scientometric and systematic map of these impacts in continental aquatic environments, aiming to provide an overview of research investigating the effects of temperature and acidification on pesticide toxicity. Our findings reveal a significant increase in research output on this topic, especially over the past seven years, with the United States leading due to high pesticide use and rigorous environmental monitoring.
View Article and Find Full Text PDFWe experimentally tested the effects of different concentrations of cigarette butt leachate on freshwater phytoplankton chlorophyll-a, species richness, cell density, and community composition. For this, we sampled the phytoplankton from a eutrophic lake and acclimated it for 24 h in microcosms. We then conducted the experiment in microcosms maintained for 96 h.
View Article and Find Full Text PDFCarbofuran is one of the most toxic broad-spectrum pesticides. We evaluated the effects of carbofuran on two species of microalgae, Pseudopediastrum boryanum and Desmodesmus communis, through measurements of cell viability, biomass, chlorophyll content, and the production of reactive oxygen species (ROS). The ability of these algae to remove carbofuran dissolved in the media was also determined.
View Article and Find Full Text PDFEnviron Toxicol Chem
July 2022
Atrazine is a herbicide widely used in the control of weeds in crops such as corn, sugar cane, and sorghum. It is often found in aquatic environments, where it can potentially endanger nontarget organisms such as microalgae. The present study evaluated atrazine toxicity to seven different species of Chlorophyceae and the tolerance of the species to the herbicide was related to morphological, photosynthetic, chlorophyll-a content and the activity of the glutathione-S-transferase enzyme (GST).
View Article and Find Full Text PDFThis paper presents and demonstrates the three logic processing levels based on complementary photonic crystal logic devices through photonic integrated circuit modeling. We accomplished a set of logic circuits including AND, OR, NAND, NOR, XOR, FAN-OUT, HALF ADDER, and FULL ADDER based on photonic crystal slab platforms. Furthermore, we achieved efficient all-optical logic circuits with contrast ratios as high as 5.
View Article and Find Full Text PDFThe aim of this work is to determine the varying dielectric constant of a biological nanostructured system via electrostatic force microscopy (EFM) and to show how this method is useful to study natural photonic crystals. We mapped the dielectric constant of the cross section of the posterior wing of the damselfly with nanometric resolution. We obtained structural information on its constitutive nanolayers and the absolute values of their dielectric constant.
View Article and Find Full Text PDFAtrazine (ATZ) is one of the most widely used herbicides in the world. A scientometric study was conducted to analyze the evolution of research on ATZ. The study also looked at the use of microalgae and cyanobacteria as biological models for toxicity tests during the period from 1959 to 2019, in the category of toxicology of Web of Science.
View Article and Find Full Text PDFWe theoretically propose and demonstrate through numerous simulations complementary photonic crystal integrated logic (CPCL) devices. Simulation results provide demonstration of a highly efficient clock rate, higher than 20 GHz, guaranteeing operation at both input and output with the same wavelength (around =1550). The proposed devices show well-defined output power values representing the two logic states 1 and 0, with a contrast ratio as high as 6 dB.
View Article and Find Full Text PDFAquatic environments can be easily contaminated due to anthropogenic activities that may affect local biota. Microalgae are abundant and have an important role on the food chain. Consequently, they stand out as promising models for studies of contaminants.
View Article and Find Full Text PDFMethylparaben (MeP) is one of the most used preservatives in the industry; however, the toxic effects on aquatic ecosystems are still poorly understood. Therefore, this study was conducted (1) to identify and compare the toxic effects of MeP on physiological parameters of different green microalgae species, using suitable mathematical models; and (2) to estimate a PNEC value for MeP in freshwater ecosystems, adopting either the deterministic or the probabilistic approaches. Toxicity tests were carried out with three green microalgae (Pseudopediastrum boryanum, Desmodesmus communis, Raphidocelis subcapitata), in which different endpoints such as growth rate, chlorophyll-a, and cell viability were measured and compared through the effective concentration which caused a response in x% of test organisms (ECx).
View Article and Find Full Text PDFVitamin D (VD) is a steroid prohormone that regulates the body's calcium and phosphate levels in bone mineralization. It is also well described as a fat-soluble vitamin playing an important role in immunomodulation, regulation of cytokines, and cell proliferation. Thus, VD is a powerful hormone with pleiotropic effects, which acts to maintain optimal health.
View Article and Find Full Text PDFThe iridescent wings of the Chalcopterix rutilans damselfly (Rambur) (Odonata, Polythoridae) are investigated with focused ion beam/scanning electron microscopy, transmission electron microscopy, and time-of-flight secondary ion mass spectrometry. The electron microscopy images reveal a natural photonic crystal as the source of the varying colors. The photonic crystal has a consistent number and thickness (∼195 nm) of the repeat units on the ventral side of the wing, which is consistent with the red color visible from the bottom side of the wing in all regions.
View Article and Find Full Text PDFWe investigate the effects of the excitation power on the photoluminescence spectra of aqueous CdTe/CdS core-shell quantum dots. We have focused our efforts on nanoparticles that are drop-cast on a silicon nitride substrate and dried out. Under such conditions, the emission intensity of these nanocrystals decreases exponentially and the emission center wavelength shifts with the time under laser excitation, displaying a behavior that depends on the excitation power.
View Article and Find Full Text PDFActivation of the peripheral angiotensin-(1-7)/Mas axis of the renin-angiotensin system produces important cardioprotective actions, counterbalancing the deleterious actions of an overactivity of Ang II/AT1 axis. In the present study we evaluated whether the chronic increase in Ang-(1-7) levels in the brain could ameliorate cardiac disorders observed in transgenic (mRen2)27 hypertensive rats through actions on Mas receptor. Sprague Dawley (SD) and transgenic (mRen2)27 hypertensive rats, instrumented with telemetry probe for arterial pressure (AP) measurement were subjected to 14 days of ICV infusion of Ang-(1-7) (200 ng/h) or Ang-(1-7) associated with Mas receptor antagonist (A779, 1 μg/h) or 0.
View Article and Find Full Text PDFAm J Physiol Regul Integr Comp Physiol
May 2014
Adult obese Zucker rats (OZR; >12 wk) develop elevated sympathetic nerve activity (SNA) and mean arterial pressure (MAP) with impaired baroreflexes compared with adult lean Zucker rats (LZR) and juvenile OZR (6-7 wk). In adult OZR, baroreceptor afferent nerves respond normally to changes in MAP, whereas electrical stimulation of baroreceptor afferent fibers produces smaller reductions in SNA and MAP compared with LZR. We hypothesized that impaired baroreflexes in OZR are linked to reduced activation of brain stem sites that mediate baroreflexes.
View Article and Find Full Text PDFWe evaluated effects of chronic intracerebroventricular infusion of angiotensin (Ang)-(1-7) on cardiovascular and metabolic parameters in fructose-fed (FF) rats. After 6 weeks of fructose intake (10% in drinking water), Sprague-Dawley rats were subjected to intracerebroventricular infusion of Ang-(1-7) (200 ng/h; FF+A7 group) or 0.9% sterile saline (FF group) for 4 weeks with continued access to fructose.
View Article and Find Full Text PDFWe study the reflectivity spectra of photonic crystal slab cavities using an extension of the scattering matrix method that allows treating finite sizes of the spot of the excitation beam. The details of the implementation of the method are presented and then we show that Fano resonances arise as a consequence of the electromagnetic interference between the discrete contribution of the fundamental cavity mode and the continuum contribution of the light scattered by the photonic crystal pattern. We control the asymmetry lineshape of the Fano resonance through the polarization of the incident field, which determines the relative phase between the two electromagnetic contributions to the interference.
View Article and Find Full Text PDFBackground: The use of endoscopic sympathetic blockade (ESB) to treat axillary hyperhidrosis (AH) has become more widespread recently. ESB of the T3 and T4 ganglia is more effective, although it results in a higher incidence of compensatory sweating (CS) than ESB of T4 alone. To reduce CS and improve the level of satisfaction and therapeutic success of ESB, we performed T3 ramicotomy in association with T4 ESB.
View Article and Find Full Text PDFAngiotensin-(ANG)-(1-7) is known by its central and peripheral actions, which mainly oppose the deleterious effects induced by accumulation of ANG II during pathophysiological conditions. In the present study we evaluated whether a chronic increase in ANG-(1-7) levels in the brain would modify the progression of hypertension. After DOCA-salt hypertension was induced for seven days, Sprague-Dawley rats were subjected to 14 days of intracerebroventricular (ICV) infusion of ANG-(1-7) (200 ng/h, DOCA-A7) or 0.
View Article and Find Full Text PDFWe evaluated the development of arterial hypertension, cardiac function, and collagen deposition, as well as the level of components of the renin-angiotensin system in the heart of transgenic rats that overexpress an angiotensin (Ang)-(1-7)-producing fusion protein, TGR(A1-7)3292 (TG), which induces a lifetime increase in circulating levels of this peptide. After 30 days of the induction of the deoxycorticosterone acetate (DOCA)-salt hypertension model, DOCA-TG rats were hypertensive but presented a lower systolic arterial pressure in comparison with DOCA-Sprague-Dawley (SD) rats. In contrast to DOCA-SD rats that presented left ventricle (LV) hypertrophy and diastolic dysfunction, DOCA-TG rats did not develop cardiac hypertrophy or changes in ventricular function.
View Article and Find Full Text PDFThe aim of this work was to present a small cross-sectional survey of composite restoration clinical attributes associated with choices for replacement. Ninety-four composite fillings selected to be replaced were included in this study. A questionnaire was filled out after each procedure in order to assess the clinical conditions that indicated the restoration replacement (marginal staining, unsatisfactory restoration anatomy, marginal fracture, fractured restoration body, painful symptoms, dental fracture, composite discoloration and/or restoration displacement).
View Article and Find Full Text PDFThe relative intensity of photonic modes in microcavity pillars with embedded self-assembled quantum dots is shown to be a sensitive function of quantum dot dipole orientation and position. This is deduced from a comparison of experiment and calculated intensities of light emission for many nominally identical pillars. We are able to obtain the overall degree of in-plane polarization of the quantum dot ensemble and also to obtain information on the degree of polarization along the growth axis.
View Article and Find Full Text PDFIn order to evaluate the prevalence of psychiatric disorders in a Brazilian general hospital and their association with religious denomination and religiosity, 253 inpatients were interviewed. A socio-demographic questionnaire and an instrument for diagnosis of mental disorders (MINI-Plus) were applied. Distribution of religious denominations was: Catholic 63.
View Article and Find Full Text PDFThe temperature dependence of the photoluminescence properties of a thin film of poly[2-methoxy-5-(2(')-ethylhexyloxy)-p-phenylene-vinylene], MEH-PPV, fabricated by spin coating, is analyzed. The evolution with temperature of the peak energy of the purely electronic transition, of the first vibronic band, of the effective conjugation length, and of the Huang-Rhys factors are discussed. The asymmetric character of the pure electronic transition peak and the contribution of the individual vibrational modes to the first vibronic band line shape are considered by a model developed by Cury et al.
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