684,116 research outputs found

    Heavy metal intoxication

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    Although some debate exists with regards to the subject, elements which are classified under ‘heavy metals’ have come to be those which pose a threat to humans in terms of toxicity. Intoxication with heavy metals is not a typical diagnosis as it is fairly uncommon. This can impose a risk on people who fail to be diagnosed and removed from the source of exposure, increasing morbidity and mortality. For the purposes of this review, Cadmium and Mercury will be discussed. A brief introduction of each element’s chemical and physical properties will be given, as well as its sources in the environment and any uses. Each metal’s toxicity will be illustrated using actual cases of poisoning. Any treatments for intoxication will be explained at the end of each section.peer-reviewe

    Reusable chelating resins concentrate metal ions from highly dilute solutions

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    Column chromatographic method uses new metal chelating resins for recovering heavy-metal ions from highly dilute solutions. The absorbed heavy-metal cations may be removed from the chelating resins by acid or base washes. The resins are reusable after the washes are completed

    Phytoassessment of Vetiver grass enhanced with EDTA soil amendment grown in single and mixed heavy metal–contaminated soil

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    Over the years, ethylene-diamine-tetra-acetate (EDTA) has been widely used for many purposes. However, there are inadequate phytoassessment studies conducted using EDTA in Vetiver grass. Hence, this study evaluates the phytoassessment (growth performance, accumulation trends, and proficiency of metal uptake) of Vetiver grass, Vetiveria zizanioides (Linn.) Nash in both single and mixed heavy metal (Cd, Pb, Cu, and Zn)—disodium EDTA-enhanced contaminated soil. The plant growth, metal accumulation, and overall efficiency of metal uptake by different plant parts (lower root, upper root, lower tiller, and upper tiller) were thoroughly examined. The relative growth performance, metal tolerance, and phytoassessment of heavy metal in roots and tillers of Vetiver grass were examined. Metals in plants were measured using the flame atomic absorption spectrometry (F-AAS) after acid digestion. The root-tiller (R/T) ratio, biological concentration factor (BCF), biological accumulation coefficient (BAC), tolerance index (TI), translocation factor (TF), and metal uptake efficacy were used to estimate the potential of metal accumulation and translocation in Vetiver grass. All accumulation of heavy metals were significantly higher (p \u3c 0.05) in both lower and upper roots and tillers of Vetiver grass for Cd + Pb + Cu + Zn + EDTA treatments as compared with the control. The single Zn + EDTA treatment accumulated the highest overall total amount of Zn (8068 ± 407 mg/kg) while the highest accumulation for Cu (1977 ± 293 mg/kg) and Pb (1096 ± 75 mg/kg) were recorded in the mixed Cd + Pb + Cu + Zn + EDTA treatment, respectively. Generally, the overall heavy metal accumulation trends of Vetiver grass were in the order of Zn \u3e\u3e\u3e Cu \u3e Pb \u3e\u3e Cd for all treatments. Furthermore, both upper roots and tillers of Vetiver grass recorded high tendency of accumulation for appreciably greater amounts of all heavy metals, regardless of single and/or mixed metal treatments. Thus, Vetiver grass can be recommended as a potential phytoextractor for all types of heavy metals, whereby its tillers will act as the sink for heavy metal accumulation in the presence of EDTA for all treatments

    Peltier effect in normal metal-insulator-heavy fermion metal junctions

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    A theoretical study has been undertaken of the Peltier effect in normal metal - insulator - heavy fermion metal junctions. The results indicate that, at temperatures below the Kondo temperature, such junctions can be used as electronic microrefrigerators to cool the normal metal electrode and are several times more efficient in cooling than the normal metal - heavy fermion metal junctions.Comment: 3 pages in REVTeX, 2 figures, to be published in Appl. Phys. Lett., April 7, 200

    Thumb-bangers : exploring the cultural bond between video games and heavy metal

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    « Heavy Metal Generations » is the fourth volume in the series of papers drawn from the 2012 Music, Metal and Politics international conference (http://www.inter-disciplinary.net/publishing/product/heavy-metal-generations/).Heavy metal and video games share an almost simultaneous birth, with Black Sabbath’s debut album in 1970 and Nolan Bushnell’s Computer Space in 1971. From Judas Priest’s ‘Freewheel Burning’ music video in 1984 to Tim Schafer’s Brütal Legend in 2009, the exchanges between these two subcultures have been both reciprocal and exponential. This chapter will present a historical survey of the bond between video games and heavy metal cultures through its highest-profile examples. There are two underlying reasons for this symbiosis: 1) the historical development and popular dissemination of the video game came at an opportune time, first with the video game arcades in the 1970s and early 1980s, and then with the Nintendo Entertainment System, whose technical sound-channel limitations happened to fall in line with the typical structures of heavy metal; 2) heavy metal and video games, along with their creators and consumers, have faced similar sociocultural paths and challenges, notably through the policies set in place by the PMRC and the ESRB, and a flurry of lawsuits and attacks, especially from United States congressmen, that resulted in an overlapping of their respective spaces outside dominant culture. These reasons explain the natural bond between these cultural practices, and the more recent developments like Last Chance to Reason’s Level 2 let us foresee a future where new hybrid creations could emerge

    Demons, devils and witches: the occult in heavy metal music

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    Heavy Metal has developed from a British fringe genre of rock music in the late 1960s to a global mass market consumer-good in the early twenty-first century. Early proponents of the musical style, such as Black Sabbath, Deep Purple, Judas Priest, Saxon, Uriah Heep and Iron Maiden, were mostly seeking to reach a young male audience. Songs were often filled with violent, sexist and nationalistic themes but were also speaking to the growing sense of deterioration in social and professional life. At the same time, however, Heavy Metal was seriously indebted to the legacies of blues and classical music as well as to larger literary and cultural themes. The genre also produced mythological concept albums and rewritings of classical poems. In other words, Heavy Metal tried from the beginning to locate itself in a liminal space between pedestrian mass culture and a rather elitist adherence to complexity and musical craftsmanship, speaking from a subaltern position against the hegemonic discourse. This collection of essays provides a comprehensive and multi-disciplinary look at British Heavy Metal from its beginning through The New Wave of British Heavy Metal up to the increasing internationalization and widespread acceptance in the late 1980s. The individual chapter authors approach British Heavy Metal from a textual perspective, providing critical analysis of the politics and ideology behind the lyrics, images and performances. Rather than focus on individual bands or songs, the essays collected here argue with the larger system of Heavy Metal music in mind, providing comprehensive analysis that relate directly to the larger context of British life and culture. The wide range of approaches should provide readers from various disciplines with new and original ideas about the study of this phenomenon of popular culture

    Heavy-metal binding affinity in metalloproteins: a computational approach

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    The use of biological organisms for removal of heavy-metal in situ brings down the production cost due to the lesser pre-treatment steps in the removal process. Initial assessments of the heavy-metal binding bacteria from wastewaters, indicates that Bacillus and Chryseomonas sp. exhibited positive growth response behavior when exposed to lead and cadmium [1]. This incorporation of the heavy-metal species leads to the increase in the molecular mass of the protein as shown in the SDS-PAGE result (Figure 1). In this research, two metal-binding proteins of B. subtilis 1C7I and 1P3J were analyzed and optimized using DFT method to look into the possibility of replacement of heavy metals (Cd, Cr, Hg, and Pb) in its metal active sites

    Heavy Metal Contents in Marine Sediments and Seawater at Totok Bay Area, North Sulawesi

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    The study area is located in north-eastern part of Tomini Bay, approximately 80 km south of Manado city, North Sulawesi. This area is closed to submarine tailing disposal system in Buyat Bay. Five marine sediment samples and four water samples from seawater and dig wells have been used for heavy metals (Hg, As, CN) analyses by using Atomic Absorption Spectrometry (AAS). This study is a part of research conducted by Marine Geological Institute of Indonesia on morphological changes of seabed in the Totok Bay. The result shows that concentration of mercury (Hg) in water samples taken from Ratatotok estuary is higher than standards stipulated Government Regulation (Peraturan Pemerintah/PP) No. 82/2001. Meanwhile, concentration of arsenic (As) is almost reaching its standard threshold, and conversely cyanide (CN) concentration is low. This value of mercury (Hg) concentration taken from Ratatotok estuary is much higher than water samples from of Buyat Bay estuary. Significant concentration of mercury (Hg) analysed from those particular sampling sites indicated high mercury contamination. Therefore, further examination on ground water of dig wells is necessary, especially for mercury analysis (Hg). Furthermore, comparing the formerly obtained data of mercury concentration in the sediment, this particular study concludes that the sediments in the Totok Bay had contaminated by mercury from gold-processing of illegal mining. Keywords: pollution, heavy metal, marine sediment, seawater, Totok Bay Daerah penelitian terletak di bagian timur laut Teluk Tomini, sekitar 80 km selatan kota Manado, Sulawesi Utara. Lokasi ini berdekatan dengan tempat pembuangan limbah tambang bawah laut di Teluk Buyat. Lima contoh sedimen laut, lima buah contoh air dari laut dan sumur telah digunakan untuk analisa logam berat (Hg, As, dan CN) menggunakan metode Atomic Absorption Spectrometry AAS. Studi ini merupakan bagian dari penelitian yang dilakukan oleh Marine Geological Institute of Indonesia tentang Perubahan morfologi dasar laut di Teluk Totok. Hasil penelitian menunjukkan bahwa kandungan merkuri dalam contoh air yang diambil dari sekitar muara sungai Ratatotok lebih tinggi dari standar Peraturan Pemerintah/PP No. 82/2001. Sementara itu, konsentrasi arsen (As) hampir mencapai ambang batas standar dan konsentrasi sianida (CN) jauh lebih rendah dari standar ambang batas. Nilai kandungan merkuri di estuari Ratatotok lebih tinggi dibandingkan dengan contoh air yang terukur dari muara sungai di Teluk Buyat. Kandungan merkuri yang tinggi ini menunjukkan adanya indikasi pencemaran logam berat, dan oleh karena itu air di sumur-sumur penduduk perlu dilakukan penelitian lebih lanjut, khususnya untuk analisa merkuri. Selain itu, berdasarkan perbandingan kandungan merkuri dalam sedimen pada penelitian sebelumnya, dapat disimpulkan bahwa Teluk Totok telah mengalami kontaminasi merkuri dari penambangan emas ilegal. Kata kunci: polusi, logam berat, sedimen laut, air laut, Teluk Toto

    Enhanced reverse saturable absorption and optical limiting in heavy-atom-substituted phthalocyanines

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    The reverse saturable absorption and the optical-limiting response of metal phthalocyanines can be enhanced by use of the heavy-atom effect. Phthalocyanines containing heavy-metal atoms, such as In, Sn, and Pb, show a nearly factor-of-2 enhancement in the ratio of effective excited-state to ground-state absorption cross sections compared with those containing lighter atoms, such as Al and Si. In an f/8 optical geometry, homogeneous solutions of heavy-metal phthalocyanines, at 30% linear transmission, limit 8-ns 532-nm laser pulses to ≤ 3 µJ the energy for 50% probability of eye damage) for incident energies as high as 800 µJ

    Heavy metals partioning in three French forest soils by sequential extraction procedure

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    To know the concentration of heavy metal associated to chemical compounds is important to evaluate the environmental risks on soils, particularly regarding ion bioavailability. The relative mobility and strength of binding of heavy metals to the soil components can be studied using a sequential extraction procedure which provides a meaningful comparison between different soil profiles. The heavy metals partitioning bas been identified in three different french forest soils : one cambic podzol, one calcaric cambisol and one mollic andosol, using a new sequential extraction method. Results show that metal fractionation is metal and site specific. The water leaching phase does not contain any metals. The proportion of heavy metal leached in the exchangeable and the acid — soplhuabslee is significant for Cd. The residual phase is important for Cr, Pb, and to a lesser extend for Ni. The organic matter fraction is dominant for Zn and Cu. Thus, the considered heavy metals are mainly bounded to iron oxides, to the organic matter and to the mineral residue. The order of heavy metals availability in the three soils would be : Zn>Cd>Cu>Pb>NiL&egatd;C r.i sotopes in some extracts of the extraction procedure corroborate the anthropogenic inputs for two soils. These both infomations allow to trace the origin, the mobility and the distribution of Pb in the soil