Bioaccumulation of metals, total phenolic and flavonoid contents and antioxidant activity of Rumex acetosella L. from tailings in Žitkovac (Kosovo & Metohija)

The aim of this study was to determine the bioaccumulation of the metals in Rumex acetosella L. collected from the tailings of abandoned mine in Žitkovac (near Kosovska Mitrovica, Kosovo and Metohija), and to establish the possibility of using those plants for medicinal purposes. Concentrations of heavy metals (Mn, Fe, Pb, Ni, Cr, Cu, Cd, Zn, Ca and Mg) in soil, roots and aboveground parts of R. acetosella were determined by wet mineralization with nitric and perchloric acid. The results of the research indicate that R. acetosella accumulates large amounts of Ni, Cu, Pb, Zn, Cr, and Mn. The total phenol content, the total amount of flavonoids and the antioxidant activity of three different extracts of the root and aboveground parts of R. acetosella were determined by spectrophotometric methods. The acetone extracts contain the highest concentration of phenols and flavonoids. Ethyl acetate has proven to be a solvent that releases the least amount of phenols and flavonoids. The methanol extract of aboveground parts has the highest, while acetone root extract has the lowest antioxidant activity. Rumex acetosella can be used for medicinal purposes, but only collected from uncontaminated soil.Publishe

POTENCIJAL BIOAKUMULACIJE I TRANSLOKACIJE METALA KOD VRSTE ACHILLEA MILLEFOLIUM SA RAZLICITIH LOKALITETA

Achillea millefolium L. has a great value as medicinal plant. The aim of the research is to determine the uptake potential for heavy metals and the intraspecial difference between unique species of A. millefolium from different localities based on the heavy metals uptake, their distribution in plant organs and enrichment factors. The results showed that plants growing on soil rich in heavy metals (tailings) absorb significantly higher amounts of metals compared to plants from the Ovčar-Kablar gorge (non-contaminated soil).Publishe

Aktivnost enzima katalaze i sadržaj organskih kiselina kod Hajdučke trave (Achillea millefolium) sa sanirane deponije „Žitkovac“ Rudarsko metalurško hemijskog kombinata „Trepča“

In this comparative study, the activity of enzyme catalase and total content of organic acids were determined in undergroung and above-ground plant parts of medicinal plant Achillea millefolium from tailing pond “Žitkovac” of Mining and Metallurgical Chemical Company „Trepča“ and from uncontaminated area near city of Niš. Catalase activity was measured using the gasometric method and the values obtained for this activity were expressed as ml of O2. The content of organic acids in the plant material was detrmined by modified titration method in the presence of indicator. An increased catalase activity on tailing pond, in comparison with uncontaminated habitat, is a result of stress that is caused by chemical changes in the soil on tailing pond representing good metabolic ways of detoxification, which belongs to the mechanisms of defence and acquiring resistance. An increased content of organic acids in samples on tailing pond is an efficient mechanism reducing the heavy metal uptake, binding them to complexes and allowing the plant growth at high level of contamination.U ovom komparativnom istraživanju određeni su aktivnost enzima katalaze i ukupan sadržaj organskih kiselina u podzemnim i nadzemnim delovima lekovite biljke hajdučka trava (Achillea millefolium) sa sanirane deponije „Žitkovac“ Rudarsko Metalurško Hemijskog Kombinata „Trepča“ i nezagađenog područja okoline Niša. Aktivnost katalaze je izmerena korišćenjem gasometrijske metode i izražena u ml kiseonika. Sadržaj organskih kiselina u bilјnom materijalu određen je modifikovanom metodom titracije u prisustvu indikatora. Uvećanje aktivnosti enzima katalaze kod uzoraka na deponiji u poređenju sa nezagađenim staništem je rezultat stresa uzrokovan hemijskim promenama u zemljištu i predstavlja metabolički vid razgradnje štetnih jedinjenja, odnosno detoksikacije, koja spada u kvalitetne mehanizme sticanja otpornosti, kao odgovor na izmenjene uslove u životnoj sredini. Povećan sadržaj organskih kiselina u uzorcima sa deponije je efikasan mehanizam, koji smanjuje unos teških metala u bilјku vezujući se za njih u komplekse i omogućava rast biljke pri visokom nivou kontaminacije

Error Errore Eicitur: A Stochastic Resonance Paradigm for Reliable Storage of Information on Unreliable Media

We give an architecture of a storage system consisting of a storage medium made of unreliable memory elements and an error correction circuit made of a combination of noisy and noiseless logic gates that is capable of retaining the stored information with the lower probability of error than a storage system with a correction circuit made completely of noiseless logic gates. Our correction circuit is based on the iterative decoding of low-density parity check codes, and uses the positive effect of errors in logic gates to correct errors in memory elements. In the spirit of Marcus Tullius Cicero's Clavus clavo eicitur (one nail drives out another), the proposed storage system operates on the principle: error errore eicitur-one error drives out another. The randomness that is present in the logic gates makes these classes of decoders superior to their noiseless counterparts. Moreover, random perturbations do not require any additional computational resources as they are inherent to unreliable hardware itself. To utilize the benefits of logic gate failures, our correction circuit relies on two key novelties: a mixture of reliable and unreliable gates and decoder rewinding. We present a method based on absorbing Markov chains for the probability of error analysis, and explain how the randomness in the variable and check node update function helps a decoder to escape to local minima associated with trapping sets.European Union [309129]; IUSSTF under the Indo-US Joint R&D Network Joint Centre on Data Storage Research Award [16-2014]; NSF [CCF-0963726, CCF-1314147, ECCS-1500170]; Serbian Ministry of Science [TR32028]This item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]

Adaptive Gradient Descent Bit-Flipping Diversity Decoding

In this letter we propose a novel framework for designing decoders, for Low-Density Parity Check (LDPC) codes, that surpasses the frame error rate performance of Belief-Propagation (BP) decoding on binary symmetric channels. Its key component is the adaptation method, based on the genetic optimization algorithm, that is incorporated into the recently proposed Gradient Descent Bit-Flipping Decoding with Momentum (GDBF-w/M). We show that the resulting decoder outperforms all state-of-the-art probabilistic bit-flipping decoders and, additionally, it can be trained to perform beyond BP decoding, which is verified by numerical examples that include codes used in IEEE 802.3an and 5GNR standards. The proposed framework provides a systematic method for decoder optimization without requiring knowledge of trapping sets. Moreover, it is applicable to both regular and irregular LDPC codes.National Science FoundationImmediate accessThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]

Majority Logic Decoding Under Data-Dependent Logic Gate Failures

A majority logic decoder made of unreliable logic gates, whose failures are transient and data-dependent, is analyzed. Based on a combinatorial representation of fault configurations a closed-form expression for the average bit error rate for a one-step majority logic decoder is derived, for a regular low-density parity-check (LDPC) code ensemble and the proposed failure model. The presented analysis framework is then used to establish bounds on the one-step majority logic decoder performance under the simplified probabilistic gateoutput switching model. Based on the expander property of Tanner graphs of LDPC codes, it is proven that a version of the faulty parallel bit-flipping decoder can correct a fixed fraction of channel errors in the presence of data-dependent gate failures. The results are illustrated with numerical examples of finite geometry codes.European Union [309129]; Serbian Ministry of Science [TR32028]; NSF [ECCS-1500170]; Indo-US Science and Technology Forum through the Joint Networked Center for Data Storage Research [JC-16-2014-US]This item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]

Reliability of Memories Built From Unreliable Components Under Data-Dependent Gate Failures

In this letter, we investigate fault-tolerance of memories built from unreliable cells. In order to increase the memory reliability, information is encoded by a low-density parity-check (LDPC) code, and then stored. The memory content is updated periodically by the bit-flipping decoder, built also from unreliable logic gates, whose failures are transient and data-dependent. Based on the expander property of Tanner graph of LDPC codes, we prove that the proposed memory architecture can tolerate a fixed fraction of component failures and consequently preserve all the stored information, if code length tends to infinity.Seventh Framework Programme of the European UnionThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]

Applicability of single- and two-hidden-layer neural networks in decoding linear block codes

In this paper, we analyze applicability of single- and two-hidden-layer feed-forward artificial neural networks, SLFNs and TLFNs, respectively, in decoding linear block codes. Based on the provable capability of SLFNs and TLFNs to approximate discrete functions, we discuss sizes of the network capable to perform maximum likelihood decoding. Furthermore, we propose a decoding scheme, which use artificial neural networks (ANNs) to lower the error-floors of low-density parity-check (LDPC) codes. By learning a small number of error patterns, uncorrectable with typical decoders of LDPC codes, ANN can lower the error-floor by an order of magnitude, with only marginal average complexity incense.Science Fund of the Republic of SerbiaImmediate accessThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]