Determination of chilling temperature effects on nutrient elements composition and distribution in cole (Brassica oleracea L. Cv. Acephala) using the WDXRF spectroscopic technique

Cole (Brassica oleracea L. cv. Acephala) is a naturally very hardy species to (at) chilling temperatures. It has been observed that the plant species can be viable even under snow during a cold winter. The cole seedlings were grown in soil for one month. Chilling temperatures were then applied to these seedlings under controlled conditions. These seedlings were subsequently, cut into root tip, root middle part, root upper part, hypocotyl, epicotyl, petiole and leaf and sampled randomly. Concentrations of inorganic elements (Al, Si, P, S, Cl, K, Ca, Fe, and Mg) in the parts were measured by wavelength-dispersive X-ray fluorescence (WDXRF) spectrometry to test chilling temperature effects on nutrient accumulation and distribution within these seedlings. Results indicated that the distribution of some inorganic elements among organs (roots, stem and leaves) of cole plants is significantly altered by chilling stress. There was an association between chilling temperatures and distributions, and accumulations of Ca, Fe, P, Cl, S especially Si and Al in cole seedlings. In addition, the WDXRF technique is a simple, fast, economic and accurate tool for biological studies related to the determining of the amount of plant nutritions in ppm level

Effects of salicylic acid on wheat salt sensitivity

Salicylic acid (SA), a plant phenolic compound, is now considered as a hormone-like endogenous regulator, and there is a great interest to clarify its role in the defence mechanisms against biotic and abiotic stressors. In this study, investigations on the effects of foliar-applied SA on salt sensitivity, hydrogen peroxide (H2O2) generation and activities of antioxidant enzymes like peroxidase (POX) and catalase (CAT) in plant tissues under salt stress was performed. SA treatment significantly increased the fresh and dry weights in both root and shoots of wheat plants under salt stress. Similarly, POX and CAT activities were also augmented by SA treatment. While the highest POX activity was recorded at SA+120 mM NaCl, CAT activity also exhibited an increase compared to salt treatment without SA. In parallel to increasing antioxidative activity, SA treatment decreased H2O2 content when compared to plants growing under salt stress without SA. The results revealed that salt-induced deleterious effect in wheat seedlings were significantly alleviated by the SA treatment. SA can be used as a signal molecule to investigate plant defense to abiotic stress. After the application of SA, increasing tolerance of wheat seedlings to salt stress may be related to increases in antioxidative enzyme activitiy.Key words: Wheat, salicylic acid, antioxidative enzyme activities, peroxidase (POX), catalase (CAT), hydrogen peroxide (H2O2) content

Attenuation of lead toxicity by promotion of tolerance mechanism in wheat roots by lipoic acid

This study was performed to determine the possible ameliorative effect of alpha-lipoic acid (LA) against oxidative stress evoked by lead (Pb) toxicity on 5-d wheat seedlings and elucidate how this ameliorative process was mediated. Pb toxicity caused a significant reduction in early seedling growth as evidenced by stunted root and coleoptile growth. To cope with the Pb toxicity, the activities of antioxidant enzymes were significantly stimulated compared to the control. However, in spite of high activities of these enzymes, contents of reactive oxygen species (ROS), superoxide anion and hydrogen peroxide and lipid peroxidation level were significantly high compared with the control. Similarly, Pb toxicity caused a marked decrease in the level of reduced forms of ascorbate and glutathione and thus it changed their reduced/oxidized ratio in favor of oxidized forms. On the other hand, LA supplementation further promoted uptake, accumulation, and transportation of Pb by stimulating tolerance mechanism involving ion uptake/accumulation at a high level. Moreover, ROS content and lipid peroxidation level were recorded as lower than that of the stressed-ones alone. In addition, while Pb toxicity markedly reduced amylase activity by decreasing Ca2+ content in endosperms, LA supplementation mitigated the reduction in amylase activity by increasing Ca2+ content. The changes in amylase activity were supported by isozymes patterns. Taken together, LA carried out its ameliorative effect against Pb toxicity via stimulation of tolerance mechanism, and this mechanism was linked to regeneration of the other main antioxidant compounds due to its own antioxidant property instead of activation of antioxidant enzymes

Analysis of apoplastic and symplatsic antioxidant system in shallot leaves: Impacts of weak static electric and magnetic field

Cataloged from PDF version of article.Impacts of electric and magnetic fields (EFs and MFs) on a biological organism vary depending on their application style, time, and intensities. High intensity MF and EF have destructive effects on plants. However, at low intensities, these phenomena are of special interest because of the complexity of plant responses. This study reports the effects of continuous, low-intensity static MF (7 mT) and EF (20 kV/m) on growth and antioxidant status of shallot (Allium ascalonicum L.) leaves, and evaluates whether shifts in antioxidant status of apoplastic and symplastic area help plants to adapt a new environment. Growth was induced by MF but EF applied emerged as a stress factor. Despite a lack of visible symptoms of injury, lipid peroxidation and H2O2 levels increased in EF applied leaves. Certain symplastic antioxidant enzyme activities and non-enzymatic antioxidant levels increased in response to MF and EF applications. Antioxidant enzymes in the leaf apoplast, by contrast, were found to show different regulation responses to EF and MF. Our results suggest that apoplastic constituents may work as potentially important redox regulators sensing and signaling environmental changes. Static continuous MF and EF at low intensities have distinct impacts on growth and the antioxidant system in plant leaves, and weak MF is involved in antioxidant-mediated reactions in the apoplast, resulting in overcoming a possible redox imbalance

Emerging applications of upconverting nanoparticles in intestinal infection and colorectal cancer

Raminder Singh,1,2 Gokhan Dumlupinar,3,4 Stefan Andersson-Engels,3,4 Silvia Melgar1 1APC Microbiome Ireland, University College Cork, Cork, Ireland; 2School of Medicine, University College Cork, Cork, Ireland; 3Irish Photonics Integration Centre, Tyndall National Institute, Cork, Ireland; 4Department of Physics, University College Cork, Cork, Ireland Abstract: Colorectal cancer is the abnormal growth of cells in colon or rectum. Recent findings have acknowledged the role of bacterial infection and chronic inflammation in colorectal cancer initiation and progression. In order to detect and treat precancerous lesions, new tools are required, which may help to prevent or identify colorectal cancer at an early stage. To date, several different screening tests are available, including endoscopy, stool-based blood tests, and radiology-based tests. However, these analyses either lack sensitivity or are of an invasive nature. The use of fluorescently labeled probes can increase the detection sensitivity. However, autofluorescence, photobleaching, and photodamage are commonly encountered problems with fluorescence imaging. Upconverting nanoparticles (UCNPs) are recently developed lanthanide-doped nanocrystals that can be used as light-triggered luminescent probes and in drug delivery systems. In this review, we comprehensively summarize the recent developments and address future prospects of UCNP-based applications for diagnostics and therapeutic approaches associated with intestinal infection and colorectal cancer. Keywords: near infrared, imaging, bacteria, photodynamic therapy, anti-Stokes emission, inflammatio

Maintenance Monitoring System Design Of A Movable Bridge

Movable bridges are important intersection points for both highway and marine traffic. Federal agencies and movable bridge owners in the United States broadly address the need to effectively manage and maintain these complex structures. Movable bridges are unique structures due to the complex interaction between their structural, mechanical and electrical systems and mechanisms. These mechanisms provide versatility to movable bridges; however, their intricate interrelation also produces some operation and maintenance challenges. Problems related to their locations (e.g. proximity to waterways) and fatigue (stress fluctuations during the operation) also increase the maintenance cost of the movable bridges which is significantly higher than that of the fixed bridges. Operation, maintenance and repair are particular challenges for movable bridges because of their unique design. Therefore, continuous monitoring of these structures is essential to improve maintenance operation, to decrease the maintenance costs, to track and evaluate performance and to provide solution alternatives to these issues. In this study, the authors first provide an overview of the recent experiences from monitoring design and implementation on a representative movable bridge in Florida. The paper reviews a) issues and monitoring needs for the maintenance and safety of movable bridges, b) design of the sensing, data acquisition and communications; c) field implementation and challenges; d) analysis and information generation for safety, reliability and maintenance. © 2010 Taylor & Francis Group, London

Uncertainty And Reliability Analysis Using Monitoring Data And Artificial Neural Network (Ann) Calibration

Probabilistic techniques in engineering problems provide a deeper understanding of the aleatory and epistemic uncertainties inherent to the structures being analyzed. Complex engineering structures are usually analyzed with finite element techniques to incorporate all critical details with geometric representation. The prediction of structural reliability based on a pre-defined limit state can be obtained with a finite element model and can be updated using Bayesian methods with the monitoring data. Another common approach is to calibrate a finite element model with the monitoring data by minimizing the error between the analysis and the measurements, which requires more time and user interaction. The objective of this paper is to explore the comparison of the model responses and predictions between these two approaches where uncertainties are incorporated in a different manner. For this study, a test set-up which is a simplified series-parallel physical model with four structural elements (Double-H-Frame-DHF) is designed and extensively instrumented with various sensors, and monitored over time with different structural boundary conditions. A large number of simulations using the finite element model are performed under uncertainties associated with material properties, geometry, loading and boundary conditions. The boundary conditions are changed gradually and the two approaches are executed to obtain the reliability distribution at each structural state and also to predict future performance. The findings from the two approaches are compared. © 2010 Taylor & Francis Group, London

Uncertainty and reliability analysis using monitoring data and artificial neuralnetwork (ANN) calibration

Probabilistic techniques in engineering problems provide a deeper understanding of the aleatory and epistemic uncertainties inherent to the structures being analyzed. Complex engineering structures are usually analyzed with finite element techniques to incorporate all critical details with geometric representation. The prediction of structural reliability based on a pre-defined limit state can be obtained with a finite element model and can be updated using Bayesian methods with the monitoring data. Another common approach is to calibrate a finite element model with the monitoring data by minimizing the error between the analysis and the measurements, which requires more time and user interaction. The objective of this paper is to explore the comparison of the model responses and predictions between these two approaches where uncertainties are incorporated in a different manner. For this study, a test set-up which is a simplified series-parallel physical model with four structural elements (Double-H-Frame-DHF) is designed and extensively instrumented with various sensors, and monitored over time with different structural boundary conditions. A large number of simulations using the finite element model are performed under uncertainties associated with material properties, geometry, loading and boundary conditions. The boundary conditions are changed gradually and the two approaches are executed to obtain the reliability distribution at each structural state and also to predict future performance. The findings from the two approaches are compared. © 2010 Taylor & Francis Group, London