728 research outputs found

    LC50 and bioaccumulation of Cd in different life stages of Artemia urmiana

    Get PDF
    This study was conducted in vitro to assess lethality, LC50 and the possibility of bioaccumulation of cadmium in various life stages of Artemia urmiana. Artemia is highly used in aquaculture; hence the response of the organisms to pollutants, such as cadmium regarding the increase in environmental pollution is of high importance. This experiment was performed in Faculty of Marine science and Technology, Islamic Azad University and Atomic Energy Organization of Iran in 2009. In the first stage, smaller than 1day naupliis were exposed to 10 different concentrations from 0 to 250mg/l Cd. LC50 of Cd in 24h of A. urmiana exposure was 189.33mg/L. Next, the accumulations of Cd in 5, 10, 15 and 20mg/l Cd were examined in 1, 5, 11 and 17 days of Artemia urmiana life. The results showed that Artemia urmiana has the ability of accumulation of cadmium and the accumulation level depends upon the concentration of the cadmium in the environment as well as different living periods of Artemia. We found that increasing the concentration of cadmium in the environment increases its accumulation in Artemia. There was a significant difference in accumulation of Cd between 5mg/l Cd (0.267ppm) and 20mg/l Cd (0.364ppm) in the first day of A. urmiana life (P<0.05). In all treatments of the 11 day Artemia, bioaccumulations of Cd increased with increasing of cadmium concentration. Maximum accumulation of Cd was in 20mg/l Cd in the 11 day Artemia. Results showed that although A.urmiana is resistant to Cd, however in 250mg/l, cadmium has significant toxic effects on Artemia survival (3.33%)

    Evaluating the bioaccumulation of nickel and vanadium and their effects on the growth of Artemia urmiana and A. franciscana

    Get PDF
    Although there is growing evidence that metals can be toxic to various aquatic species, there is still insufficient knowledge to integrate this information in environmental risk assessment procedures. In this study, we have investigated bioaccumulation and effects of nickel and vanadium on mortality and growth of Artemia urmiana and Artemia franciscana. The in 24 h of A. urmiana and A. franciscana exposed to nickel and vanadium were 0.0072, 0.0114 mg/l and 0.0107 and 0.011 mg/l respectively. In growth experiments, the length of animals was considered as growth index. Results indicates that the mean length of animals in (0.001, 0.002 and 0.003 mg/l) Ni and V on first, 5th, 7th and 11th days of life significantly decreases in comparison with control groups (p<0.05).Bioaccumulation of Ni and V in the same concentration, after 24 h in nauplius and also in adults of A. urmiana and A. fransicana were statistically significantly higher than of the control groups (P < 0.05). Both species accumulate nickel and vanadium in their bodies. However A. urmiana is more resistant to the heavy metals. Results show, nickel is less toxic than vanadium on Artemia

    Optimal conditions for tissue growth and branch induction of Gracilariopsis persica

    Get PDF
    The species Gracilariopsis persica was first described by Bellorin et al. (2008). G. persica grows from late September to July and shows high growth rate from January to May in the Persian Gulf. Tissue growth and branch induction of red seaweed, Gracilariopsis persica from the Persian Gulf investigated under various culture levels of temperature, light intensity, photoperiod, salinity, initial length, propagule density and chemical preservatives. Optimal size of propagules used as seed was 2 cm and faster growth of tissue and branch induction obtained at lower density. The apical part of the G. persica showed as the starting point of growth. The G. persica showed optimal growth in PES medium at 24°C, 60μmol m-2 s-1 light intensity, 12L: 12D and salinity of 39‰. But maximum branch production occurred under condition of 24°C, 20 μmol m-2 s-1 light intensity, photoperiod of 16L: 8D and salinity 39‰. Addition of chemical preservatives of p-hydroxybenzoic acid and potassium sorbate in culture medium showed marginal suppression on tissue growth and branch induction, that suitable for preparation of semi-axenic culture condition

    A Comprehensive Evaluation of the Impact of ATM QoS Mechanisms on Network Performance for Multimedia and Data Applications

    Full text link
    The Asynchronous Transfer Mode (ATM) network is crucial due to its ability to efficiently transmit data, provide reliable connections, and support various service classes with specific Quality of Service (QoS) requirements. In this paper, we utilize the OPNET network simulation software to model an ATM network and analyze the impact of QoS classification on network performance. We investigate the effects of Constant Bit Rate (CBR), Variable Bit Rate (VBR), Available Bit Rate (ABR) and Unspecified Bit Rate (UBR) models on various network traffic types such as voice, video and data. For voice traffic, we examine key QoS parameters including Jitter, Packet Delay Variation and End-to-End Delay. For video traffic, we evaluate Packet Delay Variation and End-to-End Delay. Additionally, we analyze Download Response Time for data traffic to assess the influence of QoS on the ATM network. Our results demonstrate that CBR and VBR are preferred for real-time traffic like voice and video, providing low delay and jitter. The simulation approach enables us to test various configurations and gain insights not possible in hardware tests. Our findings can help network operators determine the optimal QoS settings and tradeoffs when deploying ATM for modern multi-service networks.Comment: Interdisciplinary Conference on Electrics and Computer (INTCEC 2024

    Deep learning-based radio frequency interference detection and mitigation for microwave radiometers with 2-D spectral features

    Get PDF
    Radio frequency interference (RFI) poses significant challenges for passive microwave radiometry used in climate studies and Earth science. Despite operating in protected frequency bands, microwave radiometers often encounter RFI from sources like air surveillance radars, 5G communications, and unmanned aerial vehicles. Traditional RFI detection methods rely on handcrafted algorithms designed for specific RFI types. This study proposes a deep learning (DL) approach, leveraging convolutional neural networks to detect various RFI types on a global scale. By learning directly from radiometer data, this data-driven method enhances detection accuracy and generalization. The DL framework processes raw moment data and Stokes parameters, dynamically labeled using quality flags, offering a robust and efficient solution for RFI detection. This approach demonstrates the potential for improved RFI mitigation in passive remote sensing applications

    Analytical Methods and Regulative Viewpoint of Antimicrobial Preservatives in Cosmetics

    Get PDF
    Cosmetics need to be resistant to microbial contamination to protect consumer health and increase shelf life, much like any other product containing water, organic and inorganic components. The aims of anti-microbiological activity are to protect consumers from potentially harmful bacteria and to preserve products subject to degradation. Chemical, physical, or physicochemical methods are used to ensure this. Organic acid preservatives, alcohols, formaldehyde releasers, halogenated preservatives, isothiazolinones, quaternary ammonium salts and chlorhexidine are among the preservatives included in the legislation. Indeed, high quantitiesare more successful from a preservation standpoint, nevertheless they are toxic to consumers, whereas low amounts can lead to microbial resistance. Accordingly, the criteria of several international legislation and validation methods for introducing microbiologically safe items to the market have become essential. Although there are many approaches based on gas chromatography (GC) as per literature, the most common methods for the determination of preservatives are based on liquid chromatography (LC). Both of these procedures, as well as capillary electrophoresis (CE) and micellar electro kinetic chromatography (MEKC), have been frequently utilized in the cosmetics industry to determine preservative levels. Analytical approaches have been primarily focused on parabens, whereas the number of available methods to investigate other preservatives is limited. There is a tendency toward the usage of miniature extraction processes where new and improved sample preparation and extraction techniques including matrix solid-phase dispersion, solid-phase extraction, pressurized liquid extraction/supercritical fluid extraction and microextraction-based method have been introduced with high levels of efficiency and extraction capacities. Considering the significance and relevance of preservatives in cosmetics, this study highlights the most recent state-of-the-art information on their safety and regulatory concerns. Given the rising influence on consumer health, sample preparation and analytical methods forpreservative detection were also investigated which have been proposed by the international scientific literature. Keywords: Preservatives, Cosmetics, Analytical Techniques, Derivatization, Extractio
    corecore