1,423 research outputs found

    Effects of salicylic acid on wheat salt sensitivity

    Get PDF
    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

    Prolonged venous bleeding due to traditional treatment with leech bite: a case report

    Get PDF
    <p>Abstract</p> <p>Introduction</p> <p>The medicinal leech, <it>Hirudo medicinalis</it>, has been used in the treatment of many diseases for thousands of years. In Turkey, it is used most commonly in the management of venous diseases of lower extremities.</p> <p>Case presentation</p> <p>A 25-year-old Turkish woman presented to our emergency room with bleeding from her left leg. She had been treated for varicose veins in her lower extremities with leeches about 24 hours before admission to the emergency room. The bleeding was controlled by applying pressure with sterile gauze upon the wound, and she was discharged. She returned after four hours having started bleeding again. Hemostasis was achieved by vein ligation under local anesthesia.</p> <p>Conclusions</p> <p>Leech bite should be evaluated as a special injury. Prolonged bleeding can be seen after leech bites. In such cases, hemostasis either with local pressure or ligation of the bleeding vessel is mandatory.</p

    Does Research on Nature of Science and Social Justice Intersect? Exploring Theoretical and Practical Convergence for Science Education

    Get PDF
    Even though enhancement of students’ understanding of social justice is thought to contribute to good citizenship, contextualising social justice in science education remains challenging for teachers because social justice is not conventionally a common feature of science teaching and learning. A separate issue in science education concerns a vast body of work on nature of science (NOS) elated to understanding of and about science. Understanding NOS is thought to contribute to scientific literacy as well as citizenship. Although social justice and NOS literatures share similar themes such as citizenship goals, the precise intersection of these literatures remains relatively understudied. In this chapter, we present an argument about how contemporary conceptualizations of NOS as well as NOS instruction might be used to promote goals related to social justice. In so doing, we aim to contribute to NOS literature by drawing on theories of social justice grounded in political philosophy. We trace the potential overlap of social justice and NOS concepts and draw out example recommendations for curriculum statements and practical teaching as well as practical teaching and learning approaches. Overall, we advocate the promotion of educational goals related to social justice through NOS instruction

    Mitochondrial DNA common deletion is not associated with thyroid, breast and colorectal tumors in Turkish patients

    Get PDF
    Recently, efforts have been focused on mitochondrial DNA changes and their relation to human cancers. Among them, a 4977 bp deletion of mitochondrial DNA, named “common deletion”, has been investigated in several types of tumors, with inconsistent results. In this study, we investigated the presence of the common deletion in tissues from 25 breast, 25 colorectal and 50 thyroid tumors and in the adjacent healthy tissues from Turkish patients. Samples from healthy volunteers were also evaluated for comparison. Two PCR-based methods were used for the detection of the common deletion. First, two pairs of primers were used to amplify wild-type and deleted mtDNA. Then, a highly sensitive nested-PCR was performed, to determine low amounts of deleted genomes. By the first method, wild-type mtDNAs were observed in all samples, but a deletion was observed in only six thyroid samples, by using the nested-PCR method. In conclusion, the mitochondrial common deletion was very rare in our study group and did not appear to be not related with cancer

    Optimal feedback control for dynamic systems with state constraints: An exact penalty approach

    Get PDF
    In this paper, we consider a class of nonlinear dynamic systems with terminal state and continuous inequality constraints. Our aim is to design an optimal feedback controller that minimizes total system cost and ensures satisfaction of all constraints. We first formulate this problem as a semi-infinite optimization problem. We then show that by using a new exact penalty approach, this semi-infinite optimization problem can be converted into a sequence of nonlinear programming problems, each of which can be solved using standard gradient-based optimization methods.We conclude the paper by discussing applications of our work to glider control

    Hypothesis: primary antiangiogenic method proposed to treat early stage breast cancer

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>Women with Down syndrome very rarely develop breast cancer even though they now live to an age when it normally occurs. This may be related to the fact that Down syndrome persons have an additional copy of chromosome 21 where the gene that codes for the antiangiogenic protein Endostatin is located. Can this information lead to a primary antiangiogenic therapy for early stage breast cancer that indefinitely prolongs remission? A key question that arises is when is the initial angiogenic switch thrown in micrometastases? We have conjectured that avascular micrometastases are dormant and relatively stable if undisturbed but that for some patients angiogenesis is precipitated by surgery. We also proposed that angiogenesis of micrometastases very rarely occurs before surgical removal of the primary tumor. If that is so, it seems possible that we could suggest a primary antiangiogenic therapy but the problem then arises that starting a therapy before surgery would interfere with wound healing.</p> <p>Results</p> <p>The therapy must be initiated at least one day prior to surgical removal of the primary tumor and kept at a Down syndrome level perhaps indefinitely. That means the drug must have virtually no toxicity and not interfere meaningfully with wound healing. This specifically excludes drugs that significantly inhibit the VEGF pathway since that is important for wound healing and because these agents have some toxicity. Endostatin is apparently non-toxic and does not significantly interfere with wound healing since Down syndrome patients have no abnormal wound healing problems.</p> <p>Conclusion</p> <p>We propose a therapy for early stage breast cancer consisting of Endostatin at or above Down syndrome levels starting at least one day before surgery and continuing at that level. This should prevent micrometastatic angiogenesis resulting from surgery or at any time later. Adjuvant chemotherapy or hormone therapy should not be necessary. This can be continued indefinitely since there is no acquired resistance that develops, as happens in most cancer therapies.</p
    corecore