The association between metal allergy, total hip arthroplasty, and revision

DEFF Research Database (Denmark)

Thyssen, Jacob Pontoppidan; Jakobsen, Stig Storgaard; Engkilde, Kåre

2009-01-01

BACKGROUND AND PURPOSE: It has been speculated that the prevalence of metal allergy may be higher in patients with implant failure. We compared the prevalence and cause of revisions following total hip arthroplasty (THA) in dermatitis patients suspected to have contact allergy and in patients...... in general with THA. Furthermore, we compared the prevalence of metal allergy in dermatitis patients with and without THA. MATERIALS AND METHODS: The Danish Hip Arthroplasty Registry (DHAR) contained detailed information on 90,697 operations. The Gentofte patch-test database contained test results...... was similar in cases (12%) and in patients from the DHAR (13%). The prevalence of metal allergy was similar in cases and controls. However, the prevalence of metal allergy was lower in cases who were patch-tested after operation (6%) than in those who were patch-tested before operation (16%) (OR = 2.9; 95% CI...

No association between pseudotumors, high serum metal-ion levels and metal hypersensitivity in large-head metal-on-metal total hip arthroplasty at 5-7-year follow-up

DEFF Research Database (Denmark)

Hjorth, Mette Holm; Stilling, Maiken; Soballe, Kjeld

2015-01-01

-ion concentrations were measured, metal allergy and atopic dermatitis were evaluated, and the questionnaires of the Oxford Hip Score (OHS), Harris Hip Score (HHS) and the Short-Form Health Survey (SF-36) were completed. RESULTS: Pseudotumors were found in eight patients, but they were asymptomatic and their serum...... pseudotumor formation, serum metal-ion levels, metal patch test reactivity, and atopic dermatitis. However, clinicians should be aware of asymptomatic pseudotumors, and we advise further exploration into the mechanisms involved in the pathogenesis of pseudotumors.......OBJECTIVE: The relationship between metal wear debris, pseudotumor formation and metal hypersensitivity is complex and not completely understood. The purpose of this study was to assess the prevalence of pseudotumor formation in a consecutive series of metal-on-metal (MoM) total hip arthroplasty...

Metal-on-Metal Total Hip Resurfacing Arthroplasty: An Evidence-Based Analysis.

Science.gov (United States)

2006-01-01

The objective of this review was to assess the safety and effectiveness of metal on metal (MOM) hip resurfacing arthroplasty for young patients compared with that of total hip replacement (THR) in the same population. Total hip replacement has proved to be very effective for late middle-aged and elderly patients with severe degenerative diseases of the hips. As indications for THR began to include younger patients and those with a more active life style, the longevity of the implant became a concern. Evidence suggests that these patients experience relatively higher rates of early implant failure and the need for revision. The Swedish hip registry, for example, has demonstrated a survival rate in excess of 80% at 20 years for those aged over 65 years, whereas this figure was 33% by 16 years in those aged under 55 years. Hip resurfacing arthroplasty is a bone-conserving alternative to THR that restores normal joint biomechanics and load transfer. The technique has been used around the world for more than 10 years, specifically in the United Kingdom and other European countries. Metal-on-metal hip resurfacing arthroplasty is an alternative procedure to conventional THR in younger patients. Hip resurfacing arthroplasty is less invasive than THR and addresses the problem of preserving femoral bone stock at the initial operation. This means that future hip revisions are possible with THR if the initial MOM arthroplasty becomes less effective with time in these younger patients. The procedure involves the removal and replacement of the surface of the femoral head with a hollow metal hemisphere, which fits into a metal acetabular cup. Hip resurfacing arthroplasty is a technically more demanding procedure than is conventional THR. In hip resurfacing, the femoral head is retained, which makes it much more difficult to access the acetabular cup. However, hip resurfacing arthroplasty has several advantages over a conventional THR with a small (28 mm) ball. First, the large

Analysis of total and dissolved heavy metals in surface water of a Mexican polluted river by total reflection X-ray fluorescence spectrometry

Energy Technology Data Exchange (ETDEWEB)

Zarazua, G. [Instituto Nacional de Investigaciones Nucleares, Gerencia de Ciencias Ambientales, Apartado Postal 18-1027, Mexico D.F., C.P. 11801 (Mexico)]. E-mail: gzo@nuclear.inin.mx; Avila-Perez, P. [Instituto Nacional de Investigaciones Nucleares, Gerencia de Ciencias Ambientales, Apartado Postal 18-1027, Mexico D.F., C.P. 11801 (Mexico); Tejeda, S. [Instituto Nacional de Investigaciones Nucleares, Gerencia de Ciencias Ambientales, Apartado Postal 18-1027, Mexico D.F., C.P. 11801 (Mexico); Barcelo-Quintal, I. [Universidad Autonoma Metropolitana, Unidad Azcapotzalco, Mexico, D.F. (Mexico); Martinez, T. [Universidad Nacional Autonoma de Mexico, Facultad de Quimica, Mexico, D.F. (Mexico)

2006-11-15

The present area of study is located in the Upper Course of the Lerma River (UCLR). The Lerma is one of the most important rivers of Mexico, where it drains highly populated and industrialized regions. The aim of the present study is to determine the heavy metal concentration of Cr, Mn, Fe, Cu and Pb in dissolved and total phases of the UCLR by means of Total Reflection X-ray Fluorescence Spectrometry (TXRF). The surface water samples were collected at 8 sites distributed following the stream flow direction of the river. Four sampling campaigns were carried out in each site in a 1-year period. A sample preparation method was applied in order to obtain the total and dissolved fraction and to destroy the organic matter. The total heavy metal average concentration decrease in the following order: Fe (2566 {mu}g/L) > Mn (300 {mu}g/L) > Cu (66 {mu}g/L) > Cr (21 {mu}g/L) > Pb (15 {mu}g/L). In general, the heavy metal concentrations in water of the UCLR are below the maximum permissible limits.

Analysis of total and dissolved heavy metals in surface water of a Mexican polluted river by total reflection X-ray fluorescence spectrometry

Science.gov (United States)

Zarazua, G.; Ávila-Pérez, P.; Tejeda, S.; Barcelo-Quintal, I.; Martínez, T.

2006-11-01

The present area of study is located in the Upper Course of the Lerma River (UCLR). The Lerma is one of the most important rivers of Mexico, where it drains highly populated and industrialized regions. The aim of the present study is to determine the heavy metal concentration of Cr, Mn, Fe, Cu and Pb in dissolved and total phases of the UCLR by means of Total Reflection X-ray Fluorescence Spectrometry (TXRF). The surface water samples were collected at 8 sites distributed following the stream flow direction of the river. Four sampling campaigns were carried out in each site in a 1-year period. A sample preparation method was applied in order to obtain the total and dissolved fraction and to destroy the organic matter. The total heavy metal average concentration decrease in the following order: Fe (2566 μg/L) > Mn (300 μg/L) > Cu (66 μg/L) > Cr (21 μg/L) > Pb (15 μg/L). In general, the heavy metal concentrations in water of the UCLR are below the maximum permissible limits.

Analysis of total and dissolved heavy metals in surface water of a Mexican polluted river by total reflection X-ray fluorescence spectrometry

International Nuclear Information System (INIS)

Zarazua, G.; Avila-Perez, P.; Tejeda, S.; Barcelo-Quintal, I.; Martinez, T.

2006-01-01

The present area of study is located in the Upper Course of the Lerma River (UCLR). The Lerma is one of the most important rivers of Mexico, where it drains highly populated and industrialized regions. The aim of the present study is to determine the heavy metal concentration of Cr, Mn, Fe, Cu and Pb in dissolved and total phases of the UCLR by means of Total Reflection X-ray Fluorescence Spectrometry (TXRF). The surface water samples were collected at 8 sites distributed following the stream flow direction of the river. Four sampling campaigns were carried out in each site in a 1-year period. A sample preparation method was applied in order to obtain the total and dissolved fraction and to destroy the organic matter. The total heavy metal average concentration decrease in the following order: Fe (2566 μg/L) > Mn (300 μg/L) > Cu (66 μg/L) > Cr (21 μg/L) > Pb (15 μg/L). In general, the heavy metal concentrations in water of the UCLR are below the maximum permissible limits

Results of thermal test of metallic molybdenum disk target and fast-acting valve testing

Energy Technology Data Exchange (ETDEWEB)

Virgo, M. [Argonne National Lab. (ANL), Argonne, IL (United States); Chemerisov, S. [Argonne National Lab. (ANL), Argonne, IL (United States); Gromov, R. [Argonne National Lab. (ANL), Argonne, IL (United States); Jonah, C. [Argonne National Lab. (ANL), Argonne, IL (United States); Vandegrift, G. F. [Argonne National Lab. (ANL), Argonne, IL (United States)

2016-12-01

This report describes the irradiation conditions for thermal testing of helium-cooled metallic disk targets that was conducted on March 9, 2016, at the Argonne National Laboratory electron linac. The four disks in this irradiation were pressed and sintered by Oak Ridge National Laboratory from molybdenum metal powder. Two of those disks were instrumented with thermocouples. Also reported are results of testing a fast-acting-valve system, which was designed to protect the accelerator in case of a target-window failure.

Pseudotumor from Metal-on-Metal Total Hip Arthroplasty Causing Unilateral Leg Edema: Case Presentation and Literature Review

Directory of Open Access Journals (Sweden)

Caleb W. Grote

2018-03-01

Full Text Available Metal-on-metal (MoM total hip arthroplasty (THA can be associated with adverse metal reactions, including pseudotumors. This case report describes a 58-year-old female with an MoM THA-related pseudotumor that caused unilateral leg edema from compression of her external iliac vein. After thorough preoperative workup to rule out infection and deep vein thrombosis and consultation with a vascular surgeon, the patient underwent revision THA and excision of her pseudotumor. She had complete resolution of her swelling at 4 years after surgery. Review of all available case reports for this rare complication revealed that almost all patients were female. All patients underwent revision THA, with resolution of their symptoms. Literature review demonstrates that women are disproportionally affected by complications associated with MoM THA. We recommend close monitoring of patients with MoM THA, particularly women, for development of adverse metal reactions.

Pseudotumour incidence, cobalt levels and clinical outcome after large head metal-on-metal and conventional metal-on-polyethylene total hip arthroplasty MID-TERM RESULTS OF A RANDOMISED CONTROLLED TRIAL

NARCIS (Netherlands)

van der Veen, H. C.; Reininga, I. H. F.; Zijlstra, W. P.; Boomsma, M. F.; Bulstra, S. K.; van Raay, J. J. A. M.

2015-01-01

We compared the incidence of pseudotumours after large head metal-on-metal (MoM) total hip arthroplasty (THA) with that after conventional metal-on-polyethylene (MoP) THA and assessed the predisposing factors to pseudotumour formation. From a previous randomised controlled trial which compared large

Optimization of heavy metals total emission, case study: Bor (Serbia)

Science.gov (United States)

Ilić, Ivana; Bogdanović, Dejan; Živković, Dragana; Milošević, Novica; Todorović, Boban

2011-07-01

The town of Bor (Serbia) is one of the most polluted towns in southeastern Europe. The copper smelter which is situated in the centre of the town is the main pollutant, mostly because of its old technology, which leads to environmental pollution caused by higher concentrations of SO 2 and PM 10. These facts show that the word is about a very polluted region in Europe which, apart from harming human health in the region itself, poses a particular danger for wider area of southeastern Europe. Optimization of heavy metal's total emission was undertaken because years of long contamination of the soil with heavy metals of anthropogenic origin created a danger that those heavy metals may enter the food chains of animals and people, which can lead to disastrous consequences. This work represents the usage of Geographic Information System (GIS) for establishing a multifactor assessment model to quantitatively divide polluted zones and for selecting control sites in a linear programming model, combined with PROMETHEE/GAIA method, Screen View modeling system, and linear programming model. The results show that emissions at some control sites need to be cut for about 40%. In order to control the background of heavy metal pollution in Bor, the ecological environment must be improved.

Unusual presentation of failed metal-on-metal total hip arthroplasty with features of neoplastic process

Directory of Open Access Journals (Sweden)

Robert P. Runner, MD

2017-06-01

Full Text Available Metal-on-metal (MoM total hip arthroplasty (THA is associated with increased incidence of failure from metallosis, adverse tissue reactions, and the formation of pseudotumors. This case highlights a 53-year-old female with an enlarging painful thigh mass 12 years status post MoM THA. Radiographs and advanced imaging revealed an atypical mass with cortical bone destruction and spiculation, concerning for periprosthetic malignancy. Open frozen section biopsy was performed before undergoing revision THA in a single episode of care. This case illustrates that massive pseudotumors can be locally aggressive causing significant femoral bone destruction and may mimic malignancy. It is important that orthopaedic surgeons, radiologists and pathologists understand the relative infrequency of periprosthetic malignancy in MoM THA to mitigate patient concerns, misdiagnosis, and allow for an evidence based discussion when treating massive pseudotumors.

Using total suspended solids (TSS) and turbidity as proxies for evaluation of metal transport in river water

International Nuclear Information System (INIS)

Nasrabadi, T.; Ruegner, H.; Sirdari, Z.Z.; Schwientek, M.; Grathwohl, P.

2016-01-01

The present study was carried out in Haraz basin (Iran) that is located in south of the Caspian Sea. The goal of this study was to establish correlations amongst total suspended solids concentration (TSS) and turbidity with total pollutant concentrations to evaluate the dissolved and particle-bound concentrations of major toxic metals. It also aimed to validate TSS and/or turbidity measurements as proxies to monitor pollutant fluxes. Eight metals, namely nickel, lead, cadmium, copper, zinc, cobalt, arsenic and strontium were analyzed for dissolved and total concentrations in water at ten locations within the catchment. TSS and turbidity were also measured. Sampling campaigns were designed to cover both the rainy (December) and the dry (May) season within the basin. The robust relationship between TSS (202–1212 mg/l) and turbidity (63–501 NTUs) in both seasons warranted their interchangeable potential as proxies within the observed ranges. Total element concentrations were plotted in separate attempts versus TSS and turbidity for all locations and both events. Very good linear correlations were attained where the slopes represent the metals concentration on suspended solids and the intercept the dissolved concentration in water. The results achieved by these linear regressions were in very good agreement with independently measured values for dissolved concentration and concentrations on river bed sediments taken at the same locations. This demonstrates that turbidity and/or TSS measurements may be used for monitoring of metal loads if once calibrated against total concentration of metals. The results also revealed that in the lower Haraz catchment metal concentrations on suspended and river bed sediment were homogeneously distributed along the investigated river stretch. This is assumed to be due to intensive gravel and sand mining activities in the upper and middle part of the catchment. - Highlights: • Turbidity is evaluated as a feasible proxy to predict

Trabecular metal acetabular components in primary total hip arthroplasty

DEFF Research Database (Denmark)

Laaksonen, Inari; Lorimer, Michelle; Gromov, Kirill

2018-01-01

Background and purpose - Trabecular metal (TM) cups have demonstrated favorable results in acetabular revision and their use in primary total hip arthroplasty (THA) is increasing. Some evidence show that TM cups might decrease periprosthetic infection (PPI) incidence. We compared the survivorship...... of TM cups with that of other uncemented cups in primary THA, and evaluated whether the use of TM cups is associated with a lower risk of PPI. Patients and methods - 10,113 primary THAs with TM cup and 85,596 THAs with other uncemented cups from 2 high-quality national arthroplasty registries were...

Competition effects in cation binding to humic acid: Conditional affinity spectra for fixed total metal concentration conditions

Science.gov (United States)

David, Calin; Mongin, Sandrine; Rey-Castro, Carlos; Galceran, Josep; Companys, Encarnació; Garcés, José Luis; Salvador, José; Puy, Jaume; Cecilia, Joan; Lodeiro, Pablo; Mas, Francesc

2010-09-01

Information on the Pb and Cd binding to a purified Aldrich humic acid (HA) is obtained from the influence of different fixed total metal concentrations on the acid-base titrations of this ligand. NICA (Non-Ideal Competitive Adsorption) isotherm has been used for a global quantitative description of the binding, which has then been interpreted by plotting the Conditional Affinity Spectra of the H + binding at fixed total metal concentrations (CAScTM). This new physicochemical tool, here introduced, allows the interpretation of binding results in terms of distributions of proton binding energies. A large increase in the acidity of the phenolic sites as the total metal concentration increases, especially in presence of Pb, is revealed from the shift of the CAScTM towards lower affinities. The variance of the CAScTM distribution, which can be used as a direct measure of the heterogeneity, also shows a significant dependence on the total metal concentration. A discussion of the factors that influence the heterogeneity of the HA under the conditions of each experiment is provided, so that the smoothed pattern exhibited by the titration curves can be justified.

Natural Remission of Major Periprosthetic Osteolysis following Total Hip Arthroplasty with Metal-on-Metal Bearings

Directory of Open Access Journals (Sweden)

Tatsuya Tamaki

2017-01-01

Full Text Available The natural course of adverse events following the use of metal-on-metal (MoM bearings in total hip arthroplasty (THA is not well known. In this article, we report the case of a patient with asymptomatic major acetabular osteolysis following MoM THA that diminished gradually without any surgical intervention. A 58-year-old male underwent one-stage bilateral MoM THA for bilateral osteoarthritis. Four years after THA, major acetabular osteolysis developed in his right hip without any local or systemic symptoms. The patient underwent a careful radiographic and clinical observation without any surgical intervention because he did not want to undergo revision surgery. The lesion gradually diminished after 7 years, and most of the osteolytic area was replaced by newly formed bone at 10 years. He continues to be followed with no evidence of cup loosening or migration. Our observation suggests that a periprosthetic osteolytic change related to the use of MoM bearings has the potential for natural remission.

Clinical and radiological evolution of Intervened patients of total arthroplasty of hip with prostheses of resuperficialization metal-metal - Preliminary report

International Nuclear Information System (INIS)

Galvan Villamarin, Fernando; Bernal Torres, Fabio A; Paez, Jose Mauricio and others

2006-01-01

The articular degeneration of the hip in young patients requires including therapeutical alternatives for the management of this population. The resurfacing prostheses with metal-metal surfaces is an alternative for this type of patients. Reports with short and medium follow up are very promising, besides the different studies of laboratory that bear, the theoretical bases for their success. In this descriptive study, observational cases series type is described the radiological and clinical evolution of patients intervened of total arthroplasty of hip with resurfacing prostheses metal-metal in the hospital el Tunal of Bogota. The results of 31 hips are presented (27 patients) with an age average of 50 years old and a medium follow up of 16 months, with a good post surgical functional result with a median of 96 in the Harris Scores. The complications presented in the patient series are described and their relation with the different factors analyzed

Novel bis-(−)-nor-meptazinol derivatives act as dual binding site AChE inhibitors with metal-complexing property

Energy Technology Data Exchange (ETDEWEB)

Zheng, Wei [Department of Medicinal Chemistry, School of Pharmacy, Fudan University, 826 Zhangheng Road, Shanghai 200032 (China); NPFPC Key Laboratory of Contraceptives and Devices, Shanghai Institute of Planned Parenthood Research, 2140 Xietu Road, Shanghai 200032 (China); Li, Juan [Department of Pharmacology, Institute of Medical Sciences, Shanghai Jiaotong University School of Medicine, 280 South Chongqing Road, Shanghai 200025 (China); Qiu, Zhuibai [Department of Medicinal Chemistry, School of Pharmacy, Fudan University, 826 Zhangheng Road, Shanghai 200032 (China); Xia, Zheng [Department of Pharmacology, Institute of Medical Sciences, Shanghai Jiaotong University School of Medicine, 280 South Chongqing Road, Shanghai 200025 (China); Li, Wei [Department of Medicinal Chemistry, School of Pharmacy, Fudan University, 826 Zhangheng Road, Shanghai 200032 (China); Yu, Lining; Chen, Hailin; Chen, Jianxing [NPFPC Key Laboratory of Contraceptives and Devices, Shanghai Institute of Planned Parenthood Research, 2140 Xietu Road, Shanghai 200032 (China); Chen, Yan; Hu, Zhuqin; Zhou, Wei; Shao, Biyun; Cui, Yongyao [Department of Pharmacology, Institute of Medical Sciences, Shanghai Jiaotong University School of Medicine, 280 South Chongqing Road, Shanghai 200025 (China); Xie, Qiong, E-mail: xiejoanxq@gmail.com [Department of Medicinal Chemistry, School of Pharmacy, Fudan University, 826 Zhangheng Road, Shanghai 200032 (China); Chen, Hongzhuan, E-mail: yaoli@shsmu.edu.cn [Department of Pharmacology, Institute of Medical Sciences, Shanghai Jiaotong University School of Medicine, 280 South Chongqing Road, Shanghai 200025 (China)

2012-10-01

The strategy of dual binding site acetylcholinesterase (AChE) inhibition along with metal chelation may represent a promising direction for multi-targeted interventions in the pathophysiological processes of Alzheimer's disease (AD). In the present study, two derivatives (ZLA and ZLB) of a potent dual binding site AChE inhibitor bis-(−)-nor-meptazinol (bis-MEP) were designed and synthesized by introducing metal chelating pharmacophores into the middle chain of bis-MEP. They could inhibit human AChE activity with IC{sub 50} values of 9.63 μM (for ZLA) and 8.64 μM (for ZLB), and prevent AChE-induced amyloid-β (Aβ) aggregation with IC{sub 50} values of 49.1 μM (for ZLA) and 55.3 μM (for ZLB). In parallel, molecular docking analysis showed that they are capable of interacting with both the catalytic and peripheral anionic sites of AChE. Furthermore, they exhibited abilities to complex metal ions such as Cu(II) and Zn(II), and inhibit Aβ aggregation triggered by these metals. Collectively, these results suggest that ZLA and ZLB may act as dual binding site AChEIs with metal-chelating potency, and may be potential leads of value for further study on disease-modifying treatment of AD. -- Highlights: ► Two novel bis-(−)-nor-meptazinol derivatives are designed and synthesized. ► ZLA and ZLB may act as dual binding site AChEIs with metal-chelating potency. ► They are potential leads for disease-modifying treatment of Alzheimer's disease.

Novel bis-(−)-nor-meptazinol derivatives act as dual binding site AChE inhibitors with metal-complexing property

International Nuclear Information System (INIS)

Zheng, Wei; Li, Juan; Qiu, Zhuibai; Xia, Zheng; Li, Wei; Yu, Lining; Chen, Hailin; Chen, Jianxing; Chen, Yan; Hu, Zhuqin; Zhou, Wei; Shao, Biyun; Cui, Yongyao; Xie, Qiong; Chen, Hongzhuan

2012-01-01

The strategy of dual binding site acetylcholinesterase (AChE) inhibition along with metal chelation may represent a promising direction for multi-targeted interventions in the pathophysiological processes of Alzheimer's disease (AD). In the present study, two derivatives (ZLA and ZLB) of a potent dual binding site AChE inhibitor bis-(−)-nor-meptazinol (bis-MEP) were designed and synthesized by introducing metal chelating pharmacophores into the middle chain of bis-MEP. They could inhibit human AChE activity with IC 50 values of 9.63 μM (for ZLA) and 8.64 μM (for ZLB), and prevent AChE-induced amyloid-β (Aβ) aggregation with IC 50 values of 49.1 μM (for ZLA) and 55.3 μM (for ZLB). In parallel, molecular docking analysis showed that they are capable of interacting with both the catalytic and peripheral anionic sites of AChE. Furthermore, they exhibited abilities to complex metal ions such as Cu(II) and Zn(II), and inhibit Aβ aggregation triggered by these metals. Collectively, these results suggest that ZLA and ZLB may act as dual binding site AChEIs with metal-chelating potency, and may be potential leads of value for further study on disease-modifying treatment of AD. -- Highlights: ► Two novel bis-(−)-nor-meptazinol derivatives are designed and synthesized. ► ZLA and ZLB may act as dual binding site AChEIs with metal-chelating potency. ► They are potential leads for disease-modifying treatment of Alzheimer's disease.

Dynamic re-weighted total variation technique and statistic Iterative reconstruction method for x-ray CT metal artifact reduction

Science.gov (United States)

Peng, Chengtao; Qiu, Bensheng; Zhang, Cheng; Ma, Changyu; Yuan, Gang; Li, Ming

2017-07-01

Over the years, the X-ray computed tomography (CT) has been successfully used in clinical diagnosis. However, when the body of the patient to be examined contains metal objects, the image reconstructed would be polluted by severe metal artifacts, which affect the doctor's diagnosis of disease. In this work, we proposed a dynamic re-weighted total variation (DRWTV) technique combined with the statistic iterative reconstruction (SIR) method to reduce the artifacts. The DRWTV method is based on the total variation (TV) and re-weighted total variation (RWTV) techniques, but it provides a sparser representation than TV and protects the tissue details better than RWTV. Besides, the DRWTV can suppress the artifacts and noise, and the SIR convergence speed is also accelerated. The performance of the algorithm is tested on both simulated phantom dataset and clinical dataset, which are the teeth phantom with two metal implants and the skull with three metal implants, respectively. The proposed algorithm (SIR-DRWTV) is compared with two traditional iterative algorithms, which are SIR and SIR constrained by RWTV regulation (SIR-RWTV). The results show that the proposed algorithm has the best performance in reducing metal artifacts and protecting tissue details.

Metal release and metal allergy after total hip replacement with resurfacing versus conventional hybrid prosthesis 5-year follow-up of 52 patients

DEFF Research Database (Denmark)

Gustafson, Klas; Jakobsen, Stig S; Lorenzen, Nina D

2014-01-01

to an increased incidence of metal allergy. METHODS: 52 hips in 52 patients (median age 60 (51-64) years, 30 women) were randomized to either a MOM hip resurfacing system (ReCap) or a standard MOP total hip arthoplasty (Mallory Head/Exeter). Spot urine samples were collected preoperatively, postoperatively, after....... RESULTS: A statistically significant 10- to 20-fold increase in urinary levels of cobalt and chromium was observed throughout the entire follow-up in the MOM group. The prevalence of metal allergy was similar between groups. INTERPRETATION: While we observed significantly increased levels of metal ions...

Tailored plasmon-induced transparency in attenuated total reflection response in a metal-insulator-metal structure.

Science.gov (United States)

Matsunaga, Kouki; Hirai, Yusuke; Neo, Yoichiro; Matsumoto, Takahiro; Tomita, Makoto

2017-12-19

We demonstrated tailored plasmon-induced transparency (PIT) in a metal (Au)-insulator (SiO 2 )-metal (Ag) (MIM) structure, where the Fano interference between the MIM waveguide mode and the surface plasmon polariton (SPP) resonance mode induced a transparency window in an otherwise opaque wavenumber (k) region. A series of structures with different thicknesses of the Ag layer were prepared and the attenuated total reflection (ATR) response was examined. The height and width of the transparency window, as well as the relevant k-domain dispersion, were controlled by adjusting the Ag layer thickness. To confirm the dependency of PIT on Ag layer thickness, we performed numerical calculations to determine the electric field amplitude inside the layers. The steep k-domain dispersion in the transparency window is capable of creating a lateral beam shift known as the Goos-Hänchen shift, for optical device and sensor applications. We also discuss the Fano interference profiles in a ω - k two-dimensional domain on the basis of Akaike information criteria.

Heavy metal pollution in vegetables grown in the vicinity of a multi-metal mining area in Gejiu, China: total concentrations, speciation analysis, and health risk.

Science.gov (United States)

Li, Yanyan; Wang, Hongbin; Wang, Haijuan; Yin, Fei; Yang, Xiaoyan; Hu, Yongjun

2014-11-01

A field survey was conducted to investigate the present situation and health risk of arsenic (As), lead (Pb), cadmium (Cd), copper (Cu), and zinc (Zn) in soils and vegetables in a multi-metal mining area, Gejiu, China. Furthermore, three vegetables (water spinach, potato, and summer squash) containing high metal concentrations were selected to further analyze metal speciation. The results showed that the average concentrations of five metals in soil exceeded the limiting values, and their bioavailable concentrations were significantly positively correlated to the total ones. Heavy metals in the edible parts of vegetables also exceeded the corresponding standards. The leaves of pakchoi, peppermint, and coriander had a strong metal-accumulative ability and they were not suitable for planting. Except the residue forms, the main forms of metals in the edible parts of three selected vegetables were ethanol-, NaCl-, and HAc-extractable fractions for As, Pb, and Cd, respectively; however, Cu was mainly presented as NaCl-extractable and Zn as HAc-extractable fractions. A high proportion of ethanol-extractable As showed that As bioactivity and toxic effects were the highest. Although the total and bioavailable Cd were high in soil, its speciation in vegetables was mainly presented as HAc-extractable fraction, which has a relatively low bioactivity. Lead and arsenic were imposing a serious threat on the local residents via vegetable consumption.

Applications of Total Scattering & Pair Distribution Function Analysis in Metal-Organic Framework Materials

DEFF Research Database (Denmark)

Xu, Hui; Birgisson, Steinar; Sommer, Sanna

structure. At the same time, there is an ongoing debate on whether the SBU is present prior, or during MOF crystallization in MOF chemistry. However, little is known about MOFs formation mechanism. Currently techniques to study the in situ MOF formation process mainly focused on after......-crystallization process, for example in situ XRD and SAXS/WAXS study on MOF formation. However, the pre-crystallization process in the early stage of MOF formation is still unexplored. In this project, total scattering and PDF study will be carried out to explore the MOF formation process in early stage. This includes......Metal-Organic Frameworks (MOFs) is constructed by metal-oxide nodes and organic ligands. The formation of different structures of metal-oxide nodes (also called secondary building units, SBU) is crucial for MOF final structures, because the connectivity of SBU greatly influence the final MOF...

Can green roof act as a sink for contaminants? A methodological study to evaluate runoff quality from green roofs.

Science.gov (United States)

Vijayaraghavan, K; Joshi, Umid Man

2014-11-01

The present study examines whether green roofs act as a sink or source of contaminants based on various physico-chemical parameters (pH, conductivity and total dissolved solids) and metals (Na, K, Ca, Mg, Al, Fe, Cr, Cu, Ni, Zn, Cd and Pb). The performance of green roof substrate prepared using perlite, vermiculite, sand, crushed brick, and coco-peat, was compared with local garden soil based on improvement of runoff quality. Portulaca grandiflora was used as green roof vegetation. Four different green roof configurations, with vegetated and non-vegetated systems, were examined for several artificial rain events (un-spiked and metal-spiked). In general, the vegetated green roof assemblies generated better-quality runoff with less conductivity and total metal ion concentration compared to un-vegetated assemblies. Of the different green roof configurations examined, P. grandiflora planted on green roof substrate acted as sink for various metals and showed the potential to generate better runoff. Copyright © 2014 Elsevier Ltd. All rights reserved.

75 FR 26956 - Clean Water Act Section 303(d): Availability of Los Angeles Area Lakes Total Maximum Daily Loads...

Science.gov (United States)

2010-05-13

... ENVIRONMENTAL PROTECTION AGENCY [FRL-9146-6] Clean Water Act Section 303(d): Availability of Los...: Notice of availability. SUMMARY: This action announces the availability of EPA proposed total maximum... nutrient, mercury, chlordane, dieldrin, DDT, PCB, and trash impairments pursuant to Clean Water Act Section...

Self-Expandable Metal Stent for Closure of a Large Leak after Total Gastrectomy

Directory of Open Access Journals (Sweden)

G. Curcio

2010-08-01

Full Text Available In recent years, self-expandable metallic stents (SEMSs have emerged as a promising treatment alternative for the bridging and sealing of esophageal perforations and extensive anastomotic leaks after esophageal resection or total gastrectomy. A 56-year-old woman underwent a total gastrectomy with Roux-en-Y end-to-side esophagojejunostomy for a gastric signet ring cell carcinoma. Ten days later, esophagogastroduodenoscopy showed a 2 cm fistula in the distal end of the Roux limb of the anastomosis. This was confirmed by gastrografin esophagography. The patient was started on total parenteral nutrition. Having deemed clipping treatment for this fistula unfeasible, we decided to insert a partially silicone-coated SEMS (Evolution Controlled Release Esophageal Stent System, Cook Medical, Winston-Salem, N.C., USA. The stent was removed after ten days. Gastrografin esophagography showed no further contrast extravasation, and esophagogastroduodenoscopy showed closure of the fistula. No clinical complications were observed, and the patient was able to start normal per os nutrition. In conclusion, the treatment of symptomatic leaks in patients who have undergone esophagojejunostomy is challenging, and leakage from the jejunal stump can be a potentially serious complication. In the treatment of leakage after total gastrectomy, plastic stents (which are either too light or exercise too little radial force and totally covered metallic stents may not adhere sufficiently to the esophagojeujunal walls and, as a result, migrate beyond the anastomosis. The promising results of this report suggest that early stenting, using a partially silicone-coated SEMS, is a feasible alternative to surgical treatment in this category of patients.

What Are Normal Metal Ion Levels After Total Hip Arthroplasty? A Serologic Analysis of Four Bearing Surfaces.

Science.gov (United States)

Barlow, Brian T; Ortiz, Philippe A; Boles, John W; Lee, Yuo-Yu; Padgett, Douglas E; Westrich, Geoffrey H

2017-05-01

The recent experiences with adverse local tissue reactions have highlighted the need to establish what are normal serum levels of cobalt (Co), chromium (Cr), and titanium (Ti) after hip arthroplasty. Serum Co, Cr, and Ti levels were measured in 80 nonconsecutive patients with well-functioning unilateral total hip arthroplasty and compared among 4 bearing surfaces: ceramic-on-ceramic (CoC); ceramic-on-polyethylene (CoP); metal-on-polyethylene (MoP), and dual mobility (DM). The preoperative and most recent University of California, Los Angeles (UCLA) and Western Ontario and McMaster Universities Arthritis Index (WOMAC) scores were compared among the different bearing surfaces. No significant difference was found among serum Co and Cr levels between the 4 bearing surface groups (P = .0609 and P = .1577). Secondary analysis comparing metal and ceramic femoral heads demonstrated that the metal group (MoP, modular dual mobility (Stryker Orthopedics, Mahwah, NJ) [metal]) had significant higher serum Co levels compared with the ceramic group (CoC, CoP, MDM [ceramic]) (1.05 mg/L ± 1.25 vs 0.59 mg/L ± 0.24; P = .0411). Spearman coefficient identified no correlation between metal ion levels and patient-reported outcome scores. No serum metal ion level differences were found among well-functioning total hip arthroplasty with modern bearing couples. Significantly higher serum Co levels were seen when comparing metal vs ceramic femoral heads in this study and warrants further investigation. Metal ion levels did not correlate with patient-reported outcome measures. Copyright © 2016 Elsevier Inc. All rights reserved.

Size distribution and source identification of total suspended particulate matter and associated heavy metals in the urban atmosphere of Delhi.

Science.gov (United States)

Srivastava, Arun; Jain, V K

2007-06-01

A study of the atmospheric particulate size distribution of total suspended particulate matter (TSPM) and associated heavy metal concentrations has been carried out for the city of Delhi. Urban particles were collected using a five-stage impactor at six sites in three different seasons, viz. winter, summer and monsoon in the year 2001. Five samples from each site in each season were collected. Each sample (filter paper) was extracted with a mixture of nitric acid, hydrochloric acid and hydrofluoric acid. The acid solutions of the samples were analysed in five-particle fractions by atomic absorption spectrometry (AAS). The impactor stage fractionation of particles shows that a major portion of TSPM concentration is in the form of PM0.7 (i.e. metal mass viz. Mn, Cr, Cd, Pb, Ni, and Fe are also concentrated in the PM0.7 mode. The only exceptions are size distributions pertaining to Cu and Ca. Though, Cu is more in PM0.7 mode, its presence in size intervals 5.4-1.6microm and 1.6-0.7microm is also significant, whilst in case of Ca there is no definite pattern in its distribution with size of particles. The average PM10.9 (i.e. Source apportionment reveals that there are two sources of TSPM and PM10.9, while three and four sources were observed for PM1.6 (i.e. <1.6microm) and PM0.7, respectively. Results of regression analyses show definite correlations between PM10.9 and other fine size fractions, suggesting PM10.9 may adequately act as a surrogate for both PM1.6 and PM0.7, while PM1.6 may adequately act as a surrogate for PM0.7.

Assessment of the characteristic of nutrients, total metals, and fecal coliform in Sibu Laut River, Sarawak, Malaysia

Science.gov (United States)

Soo, Chen-Lin; Ling, Teck-Yee; Lee, Nyanti; Apun, Kasing

2016-03-01

The concentrations of nutrients (nitrogen and phosphorus), total metals, and fecal coliform (FC) coupling with chlorophyll- a (chl- a), 5-day biochemical oxygen demand (BOD5) and other general environmental parameters were evaluated at the sub-surface and near-bottom water columns of 13 stations in the Sibu Laut River during low and high slack waters. The results indicated that inorganic nitrogen (mainly nitrate) was the primary form of nitrogen whereas organic phosphorus was the major form of phosphorus. The abundance of total heavy metals in Sibu Laut River and its tributaries was in the order of Pb < Cu < Zn < Cd. Fecal coliform concentration was relatively low along Sibu Laut River. The shrimp farm effluents contributed a substantial amount of chl- a, BOD5, nutrients, and FC to the receiving creek except for total metals. Nevertheless, the influence was merely noticeable in the intake creek and amended rapidly along Selang Sibu River and brought minimal effects on the Sibu Laut River. Besides, the domestic sewage effluents from villages nearby also contributed a substantial amount of pollutants.

Airborne concentrations of metals and total dust during solid catalyst loading and unloading operations at a petroleum refinery.

Science.gov (United States)

Lewis, Ryan C; Gaffney, Shannon H; Le, Matthew H; Unice, Ken M; Paustenbach, Dennis J

2012-09-01

Workers handle catalysts extensively at petroleum refineries throughout the world each year; however, little information is available regarding the airborne concentrations and plausible exposures during this type of work. In this paper, we evaluated the airborne concentrations of 15 metals and total dust generated during solid catalyst loading and unloading operations at one of the largest petroleum refineries in the world using historical industrial hygiene samples collected between 1989 and 2006. The total dust and metals, which included aluminum, cadmium, chromium, cobalt, copper, iron, lead, manganese, molybdenum, nickel, platinum, silicon, silver, vanadium, and zinc, were evaluated in relation to the handling of four different types of solid catalysts associated with three major types of catalytic processes. Consideration was given to the known components of the solid catalysts and any metals that were likely deposited onto them during use. A total of 180 analytical results were included in this analysis, representing 13 personal and 54 area samples. Of the long-term personal samples, airborne concentrations of metals ranged from refinery and perhaps other modern refineries during the timeframe examined. Copyright © 2011 Elsevier GmbH. All rights reserved.

Bioaccumulation of heavy metals in the earthworms Lumbricus rubellus and Aporrectodea caliginosa in relation to total and available metal concentrations in field soils

International Nuclear Information System (INIS)

Hobbelen, P.H.F.; Koolhaas, J.E.; Gestel, C.A.M. van

2006-01-01

The aim of this study was to determine important metal pools for bioaccumulation by the earthworms Lumbricus rubellus and Aporrectodea caliginosa in soils with high binding capacity. Cd, Cu and Zn concentrations in soil, pore water and CaCl 2 extracts of soil, in leaves of the plant species Urtica dioica and in earthworms were determined at 15 field sites constituting a gradient in metal pollution. Variations in the Cu and Cd concentrations in L. rubellus and Cu concentrations in A. caliginosa were best explained by total soil concentrations, while variation in Cd concentration in A. caliginosa was best explained by pore water concentrations. Zn concentrations in L. rubellus and A. caliginosa were not significantly correlated to any determined variable. It is concluded that despite low availability, earthworms in floodplain soils contain elevated concentrations of Cu and Cd, suggesting that uptake takes place not only from the soluble metal concentrations. - Earthworms in floodplain soils not only accumulate heavy metals from soluble metal pools

Bioaccumulation of heavy metals in the earthworms Lumbricus rubellus and Aporrectodea caliginosa in relation to total and available metal concentrations in field soils

Energy Technology Data Exchange (ETDEWEB)

Hobbelen, P.H.F. [Department of Animal Ecology, Faculty of Earth and Life Sciences, Vrije Universiteit Amsterdam, De Boelelaan 1085, 1081 HV Amsterdam (Netherlands)]. E-mail: phobbelen@usgs.gov; Koolhaas, J.E. [Department of Animal Ecology, Faculty of Earth and Life Sciences, Vrije Universiteit Amsterdam, De Boelelaan 1085, 1081 HV Amsterdam (Netherlands); Gestel, C.A.M. van [Department of Animal Ecology, Faculty of Earth and Life Sciences, Vrije Universiteit Amsterdam, De Boelelaan 1085, 1081 HV Amsterdam (Netherlands)

2006-11-15

The aim of this study was to determine important metal pools for bioaccumulation by the earthworms Lumbricus rubellus and Aporrectodea caliginosa in soils with high binding capacity. Cd, Cu and Zn concentrations in soil, pore water and CaCl{sub 2} extracts of soil, in leaves of the plant species Urtica dioica and in earthworms were determined at 15 field sites constituting a gradient in metal pollution. Variations in the Cu and Cd concentrations in L. rubellus and Cu concentrations in A. caliginosa were best explained by total soil concentrations, while variation in Cd concentration in A. caliginosa was best explained by pore water concentrations. Zn concentrations in L. rubellus and A. caliginosa were not significantly correlated to any determined variable. It is concluded that despite low availability, earthworms in floodplain soils contain elevated concentrations of Cu and Cd, suggesting that uptake takes place not only from the soluble metal concentrations. - Earthworms in floodplain soils not only accumulate heavy metals from soluble metal pools.

Steel and Aluminum Energy Conservation and Technology Competitiveness Act of 1988: Annual report of the metals initiative for fiscal year 1996

Energy Technology Data Exchange (ETDEWEB)

NONE

1998-01-01

This annual report has been prepared for the President and Congress describing the activities carried out under the Steel and Aluminum Energy Conservation and Technology Competitiveness Act of 1988, commonly referred to as the Metals Initiative. The Act has the following purposes: (1) increase energy efficiency and enhance the competitiveness of the American steel, aluminum, and copper industries; and (2) continue research and development efforts begun under the U.S. Department of Energy (DOE) program known as the Steel Initiative. These activities are detailed in a subsequent section. Other sections describe the appropriation history, the distribution of funds through fiscal year 1996, and the estimated funds necessary to continue projects through fiscal year 1997. The Metals Initiative supported four research and development projects with the U.S. Steel industry: (1) steel plant waste oxide recycling and resource recovery by smelting, (2) electrochemical dezincing of steel scrap, (3) rapid analysis of molten metals using laser-produced plasmas, and (4) advanced process control. There are three Metals Initiative projects with the aluminum industry: (1) evaluation of TiB2-G cathode components, (2) energy efficient pressure calciner, and (3) spray forming of aluminum. 1 tab.

Steel and Aluminum Energy Conservation and Technology Competitiveness Act of 1988: Annual report of the metals initiative for fiscal year 1996

International Nuclear Information System (INIS)

1998-01-01

This annual report has been prepared for the President and Congress describing the activities carried out under the Steel and Aluminum Energy Conservation and Technology Competitiveness Act of 1988, commonly referred to as the Metals Initiative. The Act has the following purposes: (1) increase energy efficiency and enhance the competitiveness of the American steel, aluminum, and copper industries; and (2) continue research and development efforts begun under the U.S. Department of Energy (DOE) program known as the Steel Initiative. These activities are detailed in a subsequent section. Other sections describe the appropriation history, the distribution of funds through fiscal year 1996, and the estimated funds necessary to continue projects through fiscal year 1997. The Metals Initiative supported four research and development projects with the U.S. Steel industry: (1) steel plant waste oxide recycling and resource recovery by smelting, (2) electrochemical dezincing of steel scrap, (3) rapid analysis of molten metals using laser-produced plasmas, and (4) advanced process control. There are three Metals Initiative projects with the aluminum industry: (1) evaluation of TiB2-G cathode components, (2) energy efficient pressure calciner, and (3) spray forming of aluminum. 1 tab

Plasma trace metals during total parenteral alimentation.

Science.gov (United States)

Solomons, N W; Layden, T J; Rosenberg, I H; Vo-Khactu, K; Sandstead, H H

1976-06-01

The plasma concentrations of the trace metals zinc and copper were studied prospectively in 13 patients with gastrointestinal diseases treated with parenteral alimentation (TPA) for periods of from 8 days to 7 1/2 weeks. Plasma copper levels fell rapidly and consistently in all patients, with an overall rate of - 11 mug per 100 ml per week. Zinc concentrations declined in 10 of 13 patients at a more gradual rate. Analysis of the standard parenteral alimentation fluids revealed zinc content equivalent to 50% of the daily requirement and a negligible content of copper. From combined analysis of plasma zinc, hair zinc, and taste acuity, there is evidence that increased utilization or redistribution within the body may effect plasma concentrations in some patients. Neither an increase in urinary excretion nor a primary decrease in plasma binding proteins appeared to be a major factor in lowering plasma trace metal concentrations. These findings indicate that a marked decrease in plasma copper is regular and a decline in plasma zinc is common during TPA using fluids unsupplemented with trace metals. Supplementation of parenteral alimentation fluids with the trace metals zinc and copper is recommended.

Biomaterial Hypersensitivity: Is It Real? Supportive Evidence and Approach Considerations for Metal Allergic Patients following Total Knee Arthroplasty

Directory of Open Access Journals (Sweden)

Andrew J. Mitchelson

2015-01-01

Full Text Available The prospect of biomaterial hypersensitivity developing in response to joint implant materials was first presented more than 30 years ago. Many studies have established probable causation between first-generation metal-on-metal hip implants and hypersensitivity reactions. In a limited patient population, implant failure may ultimately be related to metal hypersensitivity. The examination of hypersensitivity reactions in current-generation metal-on-metal knee implants is comparatively limited. The purpose of this study is to summarize all available literature regarding biomaterial hypersensitivity after total knee arthroplasty, elucidate overall trends about this topic in the current literature, and provide a foundation for clinical approach considerations when biomaterial hypersensitivity is suspected.

Total and available heavy metal concentrations in soils of the Thriassio plain (Greece) and assessment of soil pollution indexes.

Science.gov (United States)

Massas, Ioannis; Kalivas, Dionisios; Ehaliotis, Constantions; Gasparatos, Dionisios

2013-08-01

The Thriassio plain is located 25 km west of Athens city, the capital of Greece. Two major towns (Elefsina and Aspropyrgos), heavy industry plants, medium to large-scale manufacturing, logistics plants, and agriculture comprise the main land uses of the studied area. The aim of the present study was to measure the total and available concentrations of Cr, Zn, Ni, Pb, Co, Mn, Ba, Cu, and Fe in the top soils of the plain, and to asses soil contamination by these metals by using the geoaccumulation index (I geo), the enrichment factor (EF), and the availability ratio (AR) as soil pollution indexes. Soil samples were collected from 90 sampling sites, and aqua regia and DTPA extractions were carried out to determine total and available metal forms, respectively. Median total Cr, Zn, Ni, Pb, Co, Mn, Ba, Cu, and Fe concentrations were 78, 155, 81, 112, 24, 321, 834, 38, and 16 × 10(3) mg kg(-1), respectively. The available fractions showed much lower values with medians of 0.4, 5.6, 1.7, 6.9, 0.8, 5.7, 19.8, 2.1, and 2.9 mg kg(-1). Though median total metal concentrations are not considered as particularly high, the I geo and the EF values indicate moderate to heavy soil enrichment. For certain metals such as Cr, Ni, Cu, and Ba, the different distribution patterns between the EFs and the ARs suggest different origin of the total and the available metal forms. The evaluation of the EF and AR data sets for the soils of the two towns further supports the argument that the EFs can well demonstrate the long-term history of soil pollution and that the ARs can adequately portray the recent history of soil pollution.

Formation of a pseudotumor in total hip arthroplasty using a tribological metal-polyethylene pair

Directory of Open Access Journals (Sweden)

Lorenzo Fagotti

2015-12-01

Full Text Available ABSTRACT The aim here was to report a case of a young adult patient who evolved with tumor formation in the left thigh, 14 years after revision surgery on hip arthroplasty. Davies in 2005 made the first description of this disease in patients undergoing metal-on-metal hip arthroplasty. Over the last decade, however, pseudotumors around metal-on-polyethylene surfaces have become more prevalent. Our patient presented with increased volume of the left thigh 8 years after hip arthroplasty revision surgery. Two years before the arising of the tumor in the thigh, a nodule in the inguinal region was investigated to rule out a malignant neoplastic process, but the results were inconclusive. The main preoperative complaints were pain, functional limitation and marked reduction in the range of motion of the left hip. Plain radiographs showed loosening of acetabular and femoral, and a large mass between the muscle planes was revealed through magnetic resonance imaging of the left thigh. The surgical procedure consisted of resection of the lesion and removal of the components through lateral approach. In respect of total hip arthroplasty, pseudotumors are benign neoplasms in which the bearing surface consists of metal-on-metal, but they can also occur in different tribological pairs, as presented in this case.

Optimization of metal artefact reduction (MAR) sequences for MRI of total hip prostheses

Energy Technology Data Exchange (ETDEWEB)

Toms, A.P., E-mail: andoni.toms@nnuh.nhs.u [Department of Radiology, Norfolk and Norwich University Hospital Trust, Norwich, Norfolk NR4 7UY (United Kingdom); Smith-Bateman, C.; Malcolm, P.N.; Cahir, J. [Department of Radiology, Norfolk and Norwich University Hospital Trust, Norwich, Norfolk NR4 7UY (United Kingdom); Graves, M. [University Department of Radiology, Addenbrooke' s Hospital, Cambridge (United Kingdom)

2010-06-15

Aim: To describe the relative contribution of matrix size and bandwidth to artefact reduction in order to define optimal sequence parameters for metal artefact reduction (MAR) sequences for MRI of total hip prostheses. Methods and materials: A phantom was created using a Charnley total hip replacement. Mid-coronal T1-weighted (echo time 12 ms, repetition time 400 ms) images through the prosthesis were acquired with increasing bandwidths (150, 300, 454, 592, and 781 Hz/pixel) and increasing matrixes of 128, 256, 384, 512, 640, and 768 pixels square. Signal loss from the prosthesis and susceptibility artefact was segmented using an automated tool. Results: Over 90% of the achievable reduction in artefacts was obtained with matrixes of 256 x 256 or greater and a receiver bandwidth of approximately 400 Hz/pixel or greater. Thereafter increasing the receiver bandwidth or matrix had little impact on reducing susceptibility artefacts. Increasing the bandwidth produced a relative fall in the signal-to-noise ratio (SNR) of between 49 and 56% for a given matrix, but, in practice, the image quality was still satisfactory even with the highest bandwidth and largest matrix sizes. The acquisition time increased linearly with increasing matrix parameters. Conclusion: Over 90% of the achievable metal artefact reduction can be realized with mid-range matrices and receiver bandwidths on a clinical 1.5 T system. The loss of SNR from increasing receiver bandwidth, is preferable to long acquisition times, and therefore, should be the main tool for reducing metal artefact.

Alkali metals and group IIA metals

International Nuclear Information System (INIS)

Fenton, D.E.

1987-01-01

This chapter on the coordination complexes of the alkali metals of group IIA starts with a historical perspective of their chemistry, from simple monodentate ligands, metal-β-diketonates to the macrocyclic polyethers which act as ligands to the alkali and akaline earth metals. Other macrocyclic ligands include quarterenes, calixarenes, porphyrins, phthalocyanines and chlorophylls. A section on the naturally occurring ionophores and carboxylic ionophores is included. (UK)

A method for thickness determination of thin films of amalgamable metals by total-reflection X-ray fluorescence

International Nuclear Information System (INIS)

Bennun, L.; Greaves, E.D.; Barros, H.; Diaz-Valdes, J.

2009-01-01

A method for thickness determination of thin amalgamable metallic films by total-reflection X-ray fluorescence (TXRF) is presented. The peak's intensity in TXRF spectra are directly related to the surface density of the sample, i.e. to its thickness in a homogeneous film. Performing a traditional TXRF analysis on a thin film of an amalgamated metal, and determining the relative peak intensity of a specific metal line, the layer thickness can be precisely obtained. In the case of gold thickness determination, mercury and gold peaks overlap, hence we have developed a general data processing scheme to achieve the most precise results.

Metallic Modular Taper Junctions in Total Hip Arthroplasty

Directory of Open Access Journals (Sweden)

Timothy McTighe

2015-08-01

Full Text Available The emergence of modularity in total hip arthroplasty (THA in the 1980s and 1990s was based on the fact that the benefit of these design features outweighed the risk. The use of metallic modular junctions presents a unique set of advantages and problems for use in THA. The advantages include improvement in fit and fill of the implant to bone, restoration of joint mechanics, reduced complications in revision surgery and reduction of costly inventory. However, the risks or concerns are a little harder to identify and deal with. Certainly corrosion, and fatigue failure are the two most prevalent concerns but now the specifics of fretting wear and corrosive wear increasing particulate debris and the potential biological response is having an impact on the design and potential longevity of the reconstructed hip. Material and designs are facing a shorter life expectancy than what was previously thought, mostly due to an increasing level of physical activity by the patient. Because there are no accurate laboratory test whereby the service life and performance of these implants can be predicted, early controlled clinical evaluations are necessary. Early publication of testing and clinical impressions should be encouraged in an attempt to reduce exposure to potential at risk patients, implants and material. The reduction and possible elimination of risks will require a balancing of all the variables requiring a multidisciplinary endeavor. This paper is designed to review the risk factors, and benefits of modular junctions in total hip arthroplasty (THA. Also some basic engineering principals that can reduce risk factors and improve functionality of modular junctions.

Is the Total Concentration of a Heavy Metal in Soil a Suitable Tool for Assessing the Environmental Risk? Considering the Case of Copper

Science.gov (United States)

Fernández-Calviño, David; Pérez-Rodríguez, Paula; Nóvoa-Muñoz, Juan Carlos; Estévez, Manuel Arias

2017-01-01

National legislation concerning soil pollution by heavy metals in different countries is mostly based on the total heavy metal concentration levels allowed in different soils. As soil pollution is an issue of worldwide concern, here we develop a laboratory exercise for students in which they must check the suitability of a total metal…

Esophagojejunal Anastomosis Fistula, Distal Esophageal Stenosis, and Metalic Stent Migration after Total Gastrectomy

Directory of Open Access Journals (Sweden)

Nadim Al Hajjar

2015-01-01

Full Text Available Esophagojejunal anastomosis fistula is the main complication after a total gastrectomy. To avoid a complex procedure on friable inflamed perianastomotic tissues, a coated self-expandable stent is mounted at the site of the anastomotic leak. A complication of stenting procedure is that it might lead to distal esophageal stenosis. However, another frequently encountered complication of stenting is stent migration, which is treated nonsurgically. When the migrated stent creates life threatening complications, surgical removal is indicated. We present a case of a 67-year-old male patient who was treated at our facility for a gastric adenocarcinoma which developed, postoperatively, an esophagojejunostomy fistula, a distal esophageal stenosis, and a metallic coated self-expandable stent migration. To our knowledge, this is the first reported case of an esophagojejunostomy fistula combined with a distal esophageal stenosis as well as with a metallic coated self-expandable stent migration.

The acting wear mechanisms on metal-on-metal hip joint bearings: in-vitro results

NARCIS (Netherlands)

Wimmer, M.A.; Loos, J.; Nassutt, R.; Heitkemper, M.; Fischer, A.

2001-01-01

Metal-on-metal (MOM) hip joint bearings are currently under discussion as alternatives to metal-on-polymer (MOP) bearings. Some criteria under scrutiny are the wear resistance, the influence of wear particles on the surrounding tissue, as well as the frictional torque. In order to understand and

Determination of the concentration of total suspends solids (TSS) and heavy metals in basin rio Morote, Nicoya, Guanacaste

International Nuclear Information System (INIS)

Sanchez Murillo, Ricardo; Leon, Sandra; Saravia, Ana Yuri; Mena Sanchez, Carlos de

2009-01-01

The total concentration of suspends solids and heavy metals were determined of the Basin of rio Morote. The study spanned six sampling campaigns between April 2003 and May 2005. Sampling points were selected to correspond to places from the high basin to the mouth of the rio Morote in the Golfo de Nicoya. Suspends total solids concentration (TSS) on average exceeds 200 mg/L during the rainy season at the mouth. Enrichment of metals as: Cu, Ni, Cd and Fe was found in riverbed sediments; but not in Pb. The concentration of Zn has been near the limit value (200 mg/kg) in the dry season, value which has been established for the Environmental Protection Agency of United States (EPA). (author) [es

Total vs. internal element concentrations in Scots pine needles along a sulphur and metal pollution gradient

International Nuclear Information System (INIS)

Rautio, Pasi; Huttunen, Satu

2003-01-01

Different methods should be used for foliar analyses of trees used as bioindicators of pollution, than those analyses used in nutritional studies of trees. - Analysis of foliar elements is a commonly used method for studying tree nutrition and for monitoring the impacts of air pollutants on forest ecosystems. Interpretations based on the results of foliar element analysis may, however, be different in nutrition vs. monitoring studies. We studied the impacts of severe sulphur and metal (mainly Cu and Ni) pollution on the element concentrations (Al, Ca, Cu, Fe, K, Mg, Mn, Ni, P, Pb, S and Zn) in Scots pine (Pinus sylvestris L.) foliage along an airborne sulphur and metal pollution gradient. Emphasis was put on determining the contribution of air-borne particles that have accumulated on needle surfaces to the total foliage concentrations. A comparison of two soil extraction methods was carried out in order to obtain a reliable estimate of plant-available element concentrations in the soil. Element concentrations in the soil showed only a weak relationship with internal foliar concentrations. There were no clear differences between the total and internal needle S concentrations along the gradient, whereas at the plot closest to the metal smelter complex the total Cu concentrations in the youngest needles were 1.3-fold and Ni concentrations over 1.6-fold higher than the internal needle concentrations. Chloroform-extracted surface wax was found to have Ni and Cu concentrations of as high as 3000 and 600 μg/g of wax, respectively. Our results suggest that bioindicator studies (e.g. monitoring studies) may require different foliar analysis techniques from those used in studies on the nutritional status of trees

The research of a method for determination of total carbon, combination carbon and free carbon in beryllium metal

International Nuclear Information System (INIS)

Yang Xingzhong; Zhu Xiaohong

1996-02-01

A method for determination of total carbon, combination carbon and free carbon in beryllium metal with LECO CS-344 carbon/sulphur determinant has been studied. Tungsten-copper mixed pellets are used as flux to the determination of total carbon. Ratio of weight of the flux to the sample is greater than 20:1. Good analytical results are got. By this method the relative standard deviation is <10% when the content of total carbon in the range of 0.050%∼0.080% in beryllium. A standard steel sample of carbon is added into beryllium, the recoveries are 94%∼106%. For determination of free carbon, the sample are decomposed with 3 mol/L HCl, filtered and followed determination. By this method the relative standard deviation is ≤10% when the content of free carbon in the range of 0.006%∼0.020% in beryllium. the balance of total carbon and free carbon is equal to combination carbon. The method is used to determine the sample of content of total carbon in the range of 0.050%∼1.00%, free carbon in the range of 0.006%∼0.500% in metal beryllium. (6 refs., 1 fig., 13 tabs.)

Trace metal determinations by total-reflection x-ray fluorescence analysis in the open Atlantic Ocean

International Nuclear Information System (INIS)

Schmidt, D.; Gerwinski, W.; Radke, I.

1993-01-01

The Intergovernmental Oceanographic Commission (IOC), as a major component of its programme ''Global Investigation of Pollution in the Marine Environment'' (GIPME), maintains a long-standing project on ''Open Ocean Baseline Studies of Trace Contaminants''. Initially, the Atlantic Ocean and trace metals were selected. Four deep-water stations in the Cape Basin, Angola Basin, Cape Verde Abyssal Plain and Seine Abyssal Plain were regularly sampled for at least 36 depths. Additional samples were taken between stations. Samples were distributed to participants and a similar number of additional laboratories. As a central part of our own contribution to the project, we determined the trace heavy metals manganese, nickel, copper, zinc and lead and the lighter selenium by total-reflection X-ray fluorescence analysis. For the TXRF, the pre-enrichment of the trace metals and the separation from the salt matrix were performed by complexation with sodium dibenzyldithiocarbamate and reverse-phase chromatography. Generally, very low levels of trace elements were found in filtered and unfiltered water samples from these remote areas of the open Atlantic Ocean. Typical examples of the distributions of trace metal concentrations on depth profiles from the four deep-water stations as well as intercomparisons between the stations are presented. (author)

[Determination of total mass and morphology analysis of heavy metal in soil with potassium biphthalate-sodium hydroxide by ICP-AES].

Science.gov (United States)

Qu, Jiao; Yuan, Xing; Cong, Qiao; Wang, Shuang

2008-11-01

Blank soil was used as quality controlling samples, soil sample dealt by potassium biphthalate-sodium hydroxide buffer solution was used as check sample, mixed acid HNO3-HF-HClO4 was chosen to nitrify soil samples, and plasma emission spectrometer (ICP-AES) was used as detecting method. The authors determined the total metal mass of Mo, Pb, As, Hg, Cr, Cd, Zn, Cu and Ni in the extracted and dealt soil samples, and determined the mass of Mo, Pb, As, Hg, Cr, Cd, Zn, Cu and Ni in the three chemical morphologies, including acid extractable morphology, oxide associated morphology, and organics associated modality. The experimental results indicated that the different pH of potassium biphthalate-sodium hydroxide buffer solution had obvious influence on the total mass of heavy metal and morphology transformation. Except for metal element Pb and Zn, the addition of different pH potassium dihydrogen phosphate-sodium hydroxide buffer solution could accelerate the soil samples nitrification and the total mass determination of heavy metal in the soil samples. The potassium biphthalate-sodium hydroxide buffer solution could facilitate the acid extractable morphology of Cr, Cu, Hg and Pb, oxidation associated morphology of As, Hg, Pb and Zn and the organic associated morphology transforming of As and Hg. At pH 5.8, the maximum acid extractable morphology contents of Cu and Hg were 2.180 and 0.632 mg x kg(-1), respectively; at pH 6.2, the maximal oxidation associated morphology content of Pb could achieve 27.792 mg x kg(-1); at pH 6.0, the maximum organic associated morphology content of heavy metal Hg was 4.715 mg x kg(-1).

Quantifying metal artefact reduction using virtual monochromatic dual-layer detector spectral CT imaging in unilateral and bilateral total hip prostheses

NARCIS (Netherlands)

Wellenberg, R. H. H.; Boomsma, M. F.; van Osch, J. A. C.; Vlassenbroek, A.; Milles, J.; Edens, M. A.; Streekstra, G. J.; Slump, C. H.; Maas, M.

2017-01-01

To quantify the impact of prosthesis material and design on the reduction of metal artefacts in total hip arthroplasties using virtual monochromatic dual-layer detector Spectral CT imaging. The water-filled total hip arthroplasty phantom was scanned on a novel 128-slice Philips IQon dual-layer

Liquid metal cold trap

International Nuclear Information System (INIS)

Hundal, R.

1976-01-01

A cold trap assembly for removing impurities from a liquid metal is described. A hole between the incoming impure liquid metal and purified outgoing liquid metal acts as a continuous bleed means and thus prevents the accumulation of cover gases within the cold trap assembly

Determination of the total concentration and speciation of metal ions in river, estuarine and seawater samples.

Science.gov (United States)

Alberti, Giancarla; Biesuz, Raffaela; Pesavento, Maria

2008-12-01

Different natural water samples were investigated to determine the total concentration and the distribution of species for Cu(II), Pb(II), Al(III) and U(VI). The proposed method, named resin titration (RT), was developed in our laboratory to investigate the distribution of species for metal ions in complex matrices. It is a competition method, in which a complexing resin competes with natural ligands present in the sample to combine with the metal ions. In the present paper, river, estuarine and seawater samples, collected during a cruise in Adriatic Sea, were investigated. For each sample, two RTs were performed, using different complexing resins: the iminodiacetic Chelex 100 and the carboxylic Amberlite CG50. In this way, it was possible to detect different class of ligands. Satisfactory results have been obtained and are commented on critically. They were summarized by principal component analysis (PCA) and the correlations with physicochemical parameters allowed one to follow the evolution of the metals along the considered transect. It should be pointed out that, according to our findings, the ligands responsible for metal ions complexation are not the major components of the water system, since they form considerably weaker complexes.

Metal ions diffusion through polymeric matrices: A total reflection X-ray fluorescence study

International Nuclear Information System (INIS)

Boeykens, S.; Caracciolo, N.; D'Angelo, M.V.; Vazquez, C.

2006-01-01

This work proposes the use of X-ray fluorescence with total reflection geometry to explore the metal ions transport in aqueous hydrophilic polymer solutions. It is centered in the study of polymer concentration influence on ion diffusion. This subject is relevant to various and diverse applications, such as drug controlled release, microbiologic corrosion protection and enhanced oil recovery. It is anticipated that diffusion is influenced by various factors in these systems, including those specific to the diffusing species, such as charge, shape, molecular size, and those related to the structural complexity of the matrix as well as any specific interaction between the diffusing species and the matrix. The diffusion of nitrate salts of Ba and Mn (same charge, different hydrodynamic radii) through water-swollen polymeric solutions and gels in the 0.01% to 1% concentration ranges was investigated. The measurements of the metal concentration were performed by TXRF analysis using the scattered radiation by the sample as internal standard. Results are discussed according to different physical models for solute diffusion in polymeric solutions

Sweeping total reflection X-ray fluorescence optimisation to monitor the metallic contamination into IC manufacturing

International Nuclear Information System (INIS)

Borde, Yannick; Danel, Adrien; Roche, Agnes; Veillerot, Marc

2008-01-01

Among the methods available on the market today to control as metallic contamination in integrated circuit manufacturing, Sweeping Total reflection X-ray Fluorescence mode appears a very good method, providing fast and entire wafer mapping. With the goal of a pertinent use of Sweeping Total reflection X-ray Fluorescence in advanced Integrated Circuit manufacturing this work discusses how acceptable levels of contamination specified by the production (low levels to be detected) can be taken into account. The relation between measurement results (surface coverage, throughput, low limit of detection, limit of quantification, quantification of localized contamination) and Sweeping Total reflection X-ray Fluorescence parameters (number of measurement points and integration time per point) is presented in details. In particular, a model is proposed to explain the mismatch between actual surface contamination in a localized spot on wafer and Total reflection X-ray Fluorescence reading. Both calibration and geometric issues have been taken into account

Heavy reading in heavy metal : Unraveling the mystery of hip tissue in metal on metal total hip arthroplasty

NARCIS (Netherlands)

Boomsma, M.F.

2017-01-01

In this thesis, we investigated the use of computer tomography (CT) for the screening of patients with a metal-on-metal (MoM) hip prosthesis in two patient cohorts. With a self-established CT grading scale, we have shown that CT is a reliable method for the diagnosis of postoperative pathological

75 FR 8682 - Sunshine Act Meetings

Science.gov (United States)

2010-02-25

... futures and options in the precious and base metals markets, and to consider Federal position limits in... precious and base metals markets and related hedge exemptions on regulated futures exchanges, derivatives... COMMODITY FUTURES TRADING COMMISSION Sunshine Act Meetings Agency Holding the Meeting: Commodity...

Total and Available Heavy Metal Concentrations and Assessment of Soil Pollution Indices in Selected Soils of Zanjan

Directory of Open Access Journals (Sweden)

M. Taheri

2017-01-01

Full Text Available Introduction: Soil is a hardly renewable natural resource. Although soil degradation, caused by either human activities and natural processes is a relatively slow procedure, but its effects are long lasting and most often, irreversible in the time scale of man's life. Among the most significant soil contaminants resulting from both natural and human sources, heavy metals are more important due to their long- term toxicity effects. For evaluating soil's enrichment rate by heavy metals, a wide and full study of soils background values, including total and available fractions of heavy metal contents should be done. Zanjan province has some great mines and concentrating industries of lead and zinc especially in Angoran, Mahneshan. Unfortunately produced waste materials of these industries spread over the adjacent areas. Investigations showed that accumulation of some heavy metals in vegetables and crops planted in this region had occurred. Therefore, performing some investigations in these polluted areas and assessing pollution rate and heavy metals distribution in arable lands had prime importance. Our goals were: 1 determining the total and available amounts of Cu, Pb, Zn and Cd in the soils of arable lands in polluted areas of Zanjan city, 2 producing the distribution map for the metals mentioned above and 3 calculating pollution indices in the soils. Materials and Methods: The study area was in south west of Zanjan city. For soil sampling, a 1 Km by 1 Km grid defined in ArcGIS software on landuse layer and totally 144 points that placed on agricultural lands, due to our goals, were sampled. For sampling, in a 5m radius around the point we collected some subsamples from depth of 0 - 15 cm, and after mixing the subsamples, finally a 1Kg soil sample prepared and sent to the laboratory. Sampled soils were air dried and were passed through a 2mm sieve. Soils organic matter (OM content and texture were determined by Walkely-Black and Bouyoucos

Optimization of scan time in MRI for total hip prostheses. SEMAC tailoring for prosthetic implants containing different types of metals

Energy Technology Data Exchange (ETDEWEB)

Deligianni, X. [University of Basel Hospital, Basel (Switzerland). Div. of Radiological Physics; Merian Iselin Klinik, Basel (Switzerland). Inst. of Radiology; Bieri, O. [University of Basel Hospital, Basel (Switzerland). Div. of Radiological Physics; Elke, R. [Orthomerian, Basel (Switzerland); Wischer, T.; Egelhof, T. [Merian Iselin Klinik, Basel (Switzerland). Inst. of Radiology

2015-12-15

Magnetic resonance imaging (MRI) of soft tissues after total hip arthroplasty is of clinical interest for the diagnosis of various pathologies that are usually invisible with other imaging modalities. As a result, considerable effort has been put into the development of metal artifact reduction MRI strategies, such as slice encoding for metal artifact correction (SEMAC). Generally, the degree of metal artifact reduction with SEMAC directly relates to the overall time spent for acquisition, but there is no specific consensus about the most efficient sequence setup depending on the implant material. The aim of this article is to suggest material-tailored SEMAC protocol settings. Five of the most common total hip prostheses (1. Revision prosthesis (S-Rom), 2. Titanium alloy, 3. Mueller type (CoNiCRMo alloy), 4. Old Charnley prosthesis (Exeter/Stryker), 5. MS-30 stem (stainless-steel)) were scanned on a 1.5 T MRI clinical scanner with a SEMAC sequence with a range of artifact-resolving slice encoding steps (SES: 2 - 23) along the slice direction (yielding a total variable scan time ranging from 1 to 10 min). The reduction of the artifact volume in comparison with maximal artifact suppression was evaluated both quantitatively and qualitatively in order to establish a recommended number of steps for each case. The number of SES that reduced the artifact volume below approximately 300 mm{sup 3} ranged from 3 to 13, depending on the material. Our results showed that although 3 SES steps can be sufficient for artifact reduction for titanium prostheses, at least 11 SES should be used for prostheses made of materials such as certain alloys of stainless steel. Tailoring SES to the implant material and to the desired degree of metal artifact reduction represents a simple tool for workflow optimization of SEMAC imaging near total hip arthroplasty in a clinical setting.

Optimization of scan time in MRI for total hip prostheses. SEMAC tailoring for prosthetic implants containing different types of metals

International Nuclear Information System (INIS)

Deligianni, X.; Wischer, T.; Egelhof, T.

2015-01-01

Magnetic resonance imaging (MRI) of soft tissues after total hip arthroplasty is of clinical interest for the diagnosis of various pathologies that are usually invisible with other imaging modalities. As a result, considerable effort has been put into the development of metal artifact reduction MRI strategies, such as slice encoding for metal artifact correction (SEMAC). Generally, the degree of metal artifact reduction with SEMAC directly relates to the overall time spent for acquisition, but there is no specific consensus about the most efficient sequence setup depending on the implant material. The aim of this article is to suggest material-tailored SEMAC protocol settings. Five of the most common total hip prostheses (1. Revision prosthesis (S-Rom), 2. Titanium alloy, 3. Mueller type (CoNiCRMo alloy), 4. Old Charnley prosthesis (Exeter/Stryker), 5. MS-30 stem (stainless-steel)) were scanned on a 1.5 T MRI clinical scanner with a SEMAC sequence with a range of artifact-resolving slice encoding steps (SES: 2 - 23) along the slice direction (yielding a total variable scan time ranging from 1 to 10 min). The reduction of the artifact volume in comparison with maximal artifact suppression was evaluated both quantitatively and qualitatively in order to establish a recommended number of steps for each case. The number of SES that reduced the artifact volume below approximately 300 mm 3 ranged from 3 to 13, depending on the material. Our results showed that although 3 SES steps can be sufficient for artifact reduction for titanium prostheses, at least 11 SES should be used for prostheses made of materials such as certain alloys of stainless steel. Tailoring SES to the implant material and to the desired degree of metal artifact reduction represents a simple tool for workflow optimization of SEMAC imaging near total hip arthroplasty in a clinical setting.

Understanding how cells allocate metals using metal sensors and metallochaperones.

Science.gov (United States)

Tottey, Stephen; Harvie, Duncan R; Robinson, Nigel J

2005-10-01

Each metalloprotein must somehow acquire the correct metal. We review the insights into metal specificity in cells provided by studies of ArsR-SmtB DNA binding, metal-responsive transcriptional repressors, and a bacterial copper chaperone. Cyanobacteria are the one bacterial group that have known enzymatic demand for cytoplasmic copper import. The copper chaperone and ATPases that supply cyanobacterial plastocyanin and cytochrome oxidase are reviewed, along with related ATPases for cobalt and zinc. These studies highlight the contributions of protein-protein interactions to metal speciation. Metal sensors and metallochaperones, along with metal transporters and metal-storage proteins, act in concert not only to supply the correct metals but also to withhold the wrong ones.

Total Contents and Sequential Extraction of Heavy Metals in Soils Irrigated with Wastewater, Akaki, Ethiopia

Science.gov (United States)

Fitamo, Daniel; Itana, Fisseha; Olsson, Mats

2007-02-01

The Akaki River, laden with untreated wastes from domestic, industrial, and commercial sources, serves as a source of water for irrigating vegetable farms. The purpose of this study is to identify the impact of waste-water irrigation on the level of heavy metals and to predict their potential mobility and bioavailability. Zn and V had the highest, whereas Hg the lowest, concentrations observed in the soils. The average contents of As, Co, Cr, Cu, Ni, Zn, V, and Hg of both soils; and Pb and Se from Fluvisol surpassed the mean + 2 SD of the corresponding levels reported for their uncontaminated counterparts. Apparently, irrigation with waste water for the last few decades has contributed to the observed higher concentrations of the above elements in the study soils (Vertisol and Fluvisol) when compared to uncontaminated Vertisol and Fluvisol. On the other hand, Vertisol accommodated comparatively higher average levels of Cr, Cu, Ni, Zn, etc V, and Cd, whereas high contents of Pb and Se were observed in Fluvisol. Alternatively, comparable levels of Co and Hg were found in either soil. Except for Ni, Cr, and Cd in contaminated Vertisol, heavy metals in the soils were not significantly affected by the depth (0-20 and 30-50 cm). When the same element from the two soils was compared, the levels of Cr, Cu, Ni, Pb, Se, Zn, V, Cd at 0-20 cm; and Cr, Ni, Cu, Cd, and Zn at 30-50 cm were significantly different. Organic carbon (in both soils), CEC (Fluvisol), and clay (Vertisol) exhibited significant positive correspondences with the total heavy metal levels. Conversely, Se and Hg contents revealed perceptible associations with carbonate and pH. The exchangeable fraction was dominated by Hg and Cd, whereas the carbonate fraction was abounded with Cd, Pb, and Co. conversely, V and Pb displayed strong affinity to reducible fraction, where as Cr, Cu, Zn, and Ni dominated the oxidizable fraction. Cr, Hg, Se, and Zn (in both soils) showed preference to the residual fraction

Quantifying metal artefact reduction using virtual monochromatic dual-layer detector spectral CT imaging in unilateral and bilateral total hip prostheses

Energy Technology Data Exchange (ETDEWEB)

Wellenberg, R.H.H., E-mail: r.h.wellenberg@amc.uva.nl [Department of Radiology, Academic Medical Centre, Amsterdam (Netherlands); Boomsma, M.F., E-mail: m.f.boomsma@isala.nl [Department of Radiology, Isala, Zwolle (Netherlands); Osch, J.A.C. van, E-mail: j.a.c.van.osch@isala.nl [Department of Radiology, Isala, Zwolle (Netherlands); Vlassenbroek, A., E-mail: alain.vlassenbroek@philips.com [Philips Medical Systems, Brussels (Belgium); Milles, J., E-mail: julien.milles@philips.com [Philips Medical Systems, Eindhoven (Netherlands); Edens, M.A., E-mail: m.a.edens@isala.nl [Department of Innovation and Science, Isala, Zwolle (Netherlands); Streekstra, G.J., E-mail: g.j.streekstra@amc.uva.nl [Department of Radiology, Academic Medical Centre, Amsterdam (Netherlands); Slump, C.H., E-mail: c.h.slump@utwente.nl [MIRA Institute for Biomedical Technology and Technical Medicine, University of Twente, Enschede (Netherlands); Maas, M., E-mail: m.maas@amc.uva.nl [Department of Radiology, Academic Medical Centre, Amsterdam (Netherlands)

2017-03-15

Highlights: • Dual-layer detector CT reduces metal artefacts at high monochromatic energies (keV). • 130 keV images were optimal based on quantitative analysis on CNRs. • Optimal keVs varied from 74 to 150 keV for different hip prostheses configurations. • The Titanium alloy resulted in less severe artefacts compared to the Cobalt alloy. • Severe metal artefacts, caused by extensive photon-starvation, were not reduced. - Abstract: Purpose: To quantify the impact of prosthesis material and design on the reduction of metal artefacts in total hip arthroplasties using virtual monochromatic dual-layer detector Spectral CT imaging. Methods: The water-filled total hip arthroplasty phantom was scanned on a novel 128-slice Philips IQon dual-layer detector Spectral CT scanner at 120-kVp and 140-kVp at a standard computed tomography dose index of 20.0 mGy. Several unilateral and bilateral hip prostheses consisting of different metal alloys were inserted and combined which were surrounded by 18 hydroxyapatite calcium carbonate pellets representing bone. Images were reconstructed with iterative reconstruction and analysed at monochromatic energies ranging from 40 to 200 keV. CT numbers in Hounsfield Units (HU), noise measured as the standard deviation in HU, signal-to-noise-ratios (SNRs) and contrast-to-noise-ratios (CNRs) were analysed within fixed regions-of-interests placed in and around the pellets. Results: In 70 and 74 keV virtual monochromatic images the CT numbers of the pellets were similar to 120-kVp and 140-kVp polychromatic results, therefore serving as reference. A separation into three categories of metal artefacts was made (no, mild/moderate and severe) where pellets were categorized based on HU deviations. At high keV values overall image contrast was reduced. For mild/moderate artefacts, the highest average CNRs were attained with virtual monochromatic 130 keV images, acquired at 140-kVp. Severe metal artefacts were not reduced. In 130 keV images

Surgical Approach May Influence Survival of Large-Diameter Head Metal-on-Metal Total Hip Arthroplasty: A 6- to 10-Year Follow-Up Study

Directory of Open Access Journals (Sweden)

Chih-Chien Hu

2017-01-01

Full Text Available Large-diameter head (LDH metal-on-metal (MoM total hip arthroplasty (THA has lost popularity because of metal allergy or ALTRs (adverse local tissue reactions in the past decade. Whether the surgical approach may influence the survival of LDH-MoM-THA has not been reported. From 2006 to 2009, we performed 96 LDH-MoM-THAs on 80 patients using an in situ head-neck assembly technique through a modified Watson-Jones approach. With a mean follow-up of 8.4 years (range, 6.3–10.1 years, the implant survival rate was 100%. All patients were satisfied with the results and the Harris Hip Score improved from 52 points to 98 points. No ALTRs were found, but 17.7% of the 96 hips (17 adverse events experienced adverse events related to the cup, including 5 cases of outlier cup malposition, 11 cases of inadequate cup seating, and 1 acetabular fracture. The tissue tension that was improved by a muscle-sparing approach might lessen the chance of microseparation or edge-loading that is taken as the major risk for early implant failure. Further investigation of whether these LDH-MoM-THAs would fail or not would require a longer follow-up or even retrieval analysis in the future.

Seasonal variations of total suspended particles (TSP) and heavy metals under tropical conditions in Rio de Janeiro, Brazil

International Nuclear Information System (INIS)

Pfeiffer, W.C.; Trindade, H.A.; Costa-Ribeiro, C.; Londres, H.; Oliveira, A.E.

The total suspended particle (TSP) and heavy metal concentrations are studied in Rio de Janeiro, Brazil from 1974 until 1981. The principal aims are to determine how these things vary in two different areas and how meteorological parameters responsible for the transport and dilution of atmospheric pollutants affect these areas. (M.A.C.) [pt

Prediction of contact mechanics in metal-on-metal Total Hip Replacement for parametrically comprehensive designs and loads.

Science.gov (United States)

Donaldson, Finn E; Nyman, Edward; Coburn, James C

2015-07-16

Manufacturers and investigators of Total Hip Replacement (THR) bearings require tools to predict the contact mechanics resulting from diverse design and loading parameters. This study provides contact mechanics solutions for metal-on-metal (MoM) bearings that encompass the current design space and could aid pre-clinical design optimization and evaluation. Stochastic finite element (FE) simulation was used to calculate the head-on-cup contact mechanics for five thousand combinations of design and loading parameters. FE results were used to train a Random Forest (RF) surrogate model to rapidly predict the contact patch dimensions, contact area, pressures and plastic deformations for arbitrary designs and loading. In addition to widely observed polar and edge contact, FE results included ring-polar, asymmetric-polar, and transitional categories which have previously received limited attention. Combinations of design and load parameters associated with each contact category were identified. Polar contact pressures were predicted in the range of 0-200 MPa with no permanent deformation. Edge loading (with subluxation) was associated with pressures greater than 500 MPa and induced permanent deformation in 83% of cases. Transitional-edge contact (with little subluxation) was associated with intermediate pressures and permanent deformation in most cases, indicating that, even with ideal anatomical alignment, bearings may face extreme wear challenges. Surrogate models were able to accurately predict contact mechanics 18,000 times faster than FE analyses. The developed surrogate models enable rapid prediction of MoM bearing contact mechanics across the most comprehensive range of loading and designs to date, and may be useful to those performing bearing design optimization or evaluation. Published by Elsevier Ltd.

Total and cytosolic concentrations of twenty metals/metalloids in the liver of brown trout Salmo trutta (Linnaeus, 1758) from the karstic Croatian river Krka.

Science.gov (United States)

Dragun, Zrinka; Filipović Marijić, Vlatka; Krasnići, Nesrete; Ivanković, Dušica; Valić, Damir; Žunić, Jakov; Kapetanović, Damir; Smrzlić, Irena Vardić; Redžović, Zuzana; Grgić, Ivana; Erk, Marijana

2018-01-01

Total and cytosolic concentrations of twenty metals/metalloids in the liver of brown trout Salmo trutta (Linnaeus, 1758) were studied in the period from April 2015 to May 2016 at two sampling sites on Croatian river Krka, to establish if river water contamination with metals/metalloids downstream of Knin town has influenced metal bioaccumulation in S. trutta liver. Differences were observed between two sites, with higher concentrations of several elements (Ag, As, Ca, Co, Na, Se, Sr, V) found downstream of Knin town, whereas few others (Cd, Cs, Mo, Tl) were, unexpectedly, increased at the Krka River spring. However, total metal/metalloid concentrations in the liver of S. trutta from both sites of the Krka River were still mainly below previously reported levels for pristine freshwaters worldwide. The analysis of seasonal changes of metal/metalloid concentrations in S. trutta liver and their association with fish sex and size mostly indicated their independence of fish physiology, making them good indicators of water contamination and exposure level. Metal/metalloid concentrations in the metabolically available hepatic cytosolic fractions reported in this study are the first data of that kind for S. trutta liver, and the majority of analyzed elements were present in the cytosol in the quantity higher than 50% of their total concentrations, thus indicating their possible availability for toxic effects. However, the special attention should be directed to As, Cd, Cs, and Tl, which under the conditions of increased exposure tended to accumulate more within the cytosol. Although metal/metalloid concentrations in S. trutta liver were still rather low, monitoring of the Krka River water quality and of the health status of its biota is essential due to a trend of higher metal/metalloid bioaccumulation downstream of Knin town, especially taking into consideration the proximity of National Park Krka and the need for its conservation. Copyright © 2017 Elsevier Inc. All

Large Metal Heads and Vitamin E Polyethylene Increase Frictional Torque in Total Hip Arthroplasty.

Science.gov (United States)

Meneghini, R Michael; Lovro, Luke R; Wallace, Joseph M; Ziemba-Davis, Mary

2016-03-01

Trunnionosis has reemerged in modern total hip arthroplasty for reasons that remain unclear. Bearing frictional torque transmits forces to the modular head-neck interface, which may contribute to taper corrosion. The purpose of this study is to compare frictional torque of modern bearing couples in total hip arthroplasty. Mechanical testing based on in vivo loading conditions was used to measure frictional torque. All bearing couples were lubricated and tested at 1 Hz for more than 2000 cycles. The bearing couples tested included conventional, highly crosslinked (XLPE) and vitamin E polyethylene, CoCr, and ceramic femoral heads and dual-mobility bearings. Statistical analysis was performed using Student t test for single-variable and analysis of variance for multivariant analysis. P ≤ .05 was considered statistically significant. Large CoCr metal heads (≥36 mm) substantially increased frictional torque against XLPE liners (P = .01), a finding not observed in ceramic heads. Vitamin E polyethylene substantially increased frictional torque compared with XLPE in CoCr and ceramic heads (P = .001), whereas a difference between conventional and XLPE was not observed (P = .69) with the numbers available. Dual-mobility bearing with ceramic inner head demonstrated the lowest mean frictional torque of all bearing couples. In this simulated in vivo model, large-diameter CoCr femoral heads and vitamin E polyethylene liners are associated with increased frictional torque compared with smaller metal heads and XLPE, respectively. The increased frictional torque of vitamin E polyethylene and larger-diameter femoral heads should be considered and further studied, along with reported benefits of these modern bearing couples. Copyright © 2016 Elsevier Inc. All rights reserved.

Aerosol trace metals, particle morphology and total gaseous mercury in the atmosphere of Oxford, UK

Science.gov (United States)

Witt, M. L. I.; Meheran, N.; Mather, T. A.; de Hoog, J. C. M.; Pyle, D. M.

2010-04-01

An investigation of atmospheric trace metals was conducted in Oxford, UK, a small city ˜60 miles northwest of London, in 2007 and 2008. Concentrations of Sr, Mo, Cd, Pb, V, Cr, Mn, Fe, Co, Ni, Cu and Zn in aerosol were measured in bulk and size segregated samples. In addition, total gaseous mercury (TGM) concentrations were monitored semi-continuously by cold vapour-atomic fluorescence spectroscopy. Metal concentrations in Oxford were intermediate between previously reported levels of UK rural and urban areas for most metals studied and levels of Cd, Ni and Pb were within European guidelines. Metal concentrations appeared to be influenced by higher traffic volume on a timescale of hours. The influence of traffic on the aerosols was also suggested by the observation of carbonaceous particles via scanning electron microscopy (SEM). Air mass back trajectories suggest air masses arriving in Oxford from London and mainland Europe contained the highest metal concentrations. Aerosol samples collected over Bonfire Weekend, a period of intense firework use and lighting of bonfires in the UK, showed metal concentrations 6-46 times higher than at other times. Strontium, a tracer of firework release, was present at higher concentrations and showed a change in its size distribution from the coarse to fine mode over Bonfire Weekend. The presence of an abundance of spherical Sr particles was also confirmed in SEM images. The average TGM concentration in Oxford was 3.17 ng m -3 (st. dev. 1.59) with values recorded between 1.32 and 23.2 ng m -3. This is a higher average value than reported from nearby rural locations, although during periods when air was arriving from the west, similar concentrations to these rural areas were seen in Oxford. Comparison to meteorological data suggests that TGM in Oxford's air is highest when wind is arriving from the east/southeast. This may be due to emissions from London/mainland Europe with a possible contribution from emissions from a local

Complex metal hydrides for hydrogen, thermal and electrochemical energy storage

DEFF Research Database (Denmark)

Møller, Kasper T.; Sheppard, Drew; Ravnsbæk, Dorthe B.

2017-01-01

field. This review illustrates that complex metal hydrides may store hydrogen in the solid state, act as novel battery materials, both as electrolytes and electrode materials, or store solar heat in a more efficient manner as compared to traditional heat storage materials. Furthermore, it is highlighted...... how complex metal hydrides may act in an integrated setup with a fuel cell. This review focuses on the unique properties of light element complex metal hydrides mainly based on boron, nitrogen and aluminum, e.g., metal borohydrides and metal alanates. Our hope is that this review can provide new...

Alkali metal for ultraviolet band-pass filter

Science.gov (United States)

Mardesich, Nick (Inventor); Fraschetti, George A. (Inventor); Mccann, Timothy A. (Inventor); Mayall, Sherwood D. (Inventor); Dunn, Donald E. (Inventor); Trauger, John T. (Inventor)

1993-01-01

An alkali metal filter having a layer of metallic bismuth deposited onto the alkali metal is provided. The metallic bismuth acts to stabilize the surface of the alkali metal to prevent substantial surface migration from occurring on the alkali metal, which may degrade optical characteristics of the filter. To this end, a layer of metallic bismuth is deposited by vapor deposition over the alkali metal to a depth of approximately 5 to 10 A. A complete alkali metal filter is described along with a method for fabricating the alkali metal filter.

Relationship between metal speciation in soil solution and metal adsorption at the root surface of ryegrass

NARCIS (Netherlands)

Kalis, E.J.J.; Temminghoff, E.J.M.; Town, R.M.; Unsworth, E.R.; Riemsdijk, van W.H.

2008-01-01

Received for publication October 12, 2007. The total metal content of the soil or total metal concentration in the soil solution is not always a good indicator for metal availability to plants. Therefore, several speciation techniques have been developed that measure a defined fraction of the total

Possibilities Of Metals Extracton From Spent Metallic Automotive Catalytic Converters By Using Biometallurgical Method

Directory of Open Access Journals (Sweden)

Willner J.

2015-09-01

Full Text Available The main task of automotive catalytic converters is reducing the amount of harmful components of exhaust gases. Metallic catalytic converters are an alternative to standard ceramic catalytic converters. Metallic carriers are usually made from FeCrAl steel, which is covered by a layer of Precious Group Metals (PGMs acting as a catalyst. There are many methods used for recovery of platinum from ceramic carriers in the world, but the issue of platinum and other metals recovery from metallic carriers is poorly described. The article presents results of preliminary experiments of metals biooxidation (Fe, Cr and Al from spent catalytic converters with metallic carrier, using bacteria of the Acidithiobacillus genus.

Can plastic bag derived-microplastics act as vectors for metal exposure in terrestrial invertebrates?

Science.gov (United States)

E Hodson, Mark; Duffus-Hodson, Calum A.; Prendergast-Miller, Miranda; Thorpe, Karen

2017-04-01

Microplastics are widely reported contaminants in marine and freshwater ecosystems and studies have shown that they can be ingested by aquatic organisms and lead to potential negative effects on health. The effects can arise from the physical effects of the plastics (e.g. food displacement and blockages of the digestive tract) and from their potential to adsorb contaminants, primarily organic compounds, resulting in an increased exposure of the organism to toxic contaminants. Studies are beginning to emerge that also show a high abundance of microplastics in the terrestrial environment but there remains a lack of data on the impacts of these terrestrial microplastics or their interaction with other terrestrial pollutants. We conducted Zn adsorption experiments using HDPE microplastics, derived from plastic bags. Zinc adsorption to microplastics was similar to that observed in soils, but in the presence of both soil and microplastics, preferential adsorption onto the soil was observed. In desorption experiments, desorption of Zn from microplastics and soils was minimal (soils. In earthworm exposure experiments Lumbricus terrestris earthworms cultivated in soils containing 0.35% by mass of Zn-bearing plastic (236 - 4505 mg kg-1) ingested the microplastics with no evidence for either preferential feeding or avoidance. There was no evidence for an accumulation of the microplastics in the earthworm gut or for signs of toxicity. Our experiments demonstrate that earthworms will ingest microplastics and that microplastics can adsorb metals and act as vectors for metal exposure in soil invertebrates. However, for Zn, the risk associated with this exposure appears to be minimal.

Total petroleum hydrocarbons and trace metals in tropical estuary of Todos os Santos Bay, Brazil

Energy Technology Data Exchange (ETDEWEB)

Celino, Joil Jose; Oliveira, Olivia Maria Cordeiro de; Queiroz, Antonio Fernando de Souza [Universidade Federal da Bahia (UFBA), Salvador, BA (Brazil); Trigueis, Jorge Alberto [Universidade Estadual do Norte Fluminense (UENF), Campos dos Goytacazes, RJ (Brazil); Garcia, Karina Santos [Universidade Federal Fluminense (UFF), Niteroi, RJ (Brazil)

2008-07-01

As part of the environmental assessment within Todos os Santos Bay, State of Bahia - Brazil, in summer of 2005, superficial water and sediments samples of the mangrove were collected at five locations to determine the spatial distribution of anthropogenic pollutants in the Dom Joao estuary at the Sao Francisco do Conde Region. Sandy sediments with low organic matter content dominate the studied area. Trace metal levels indicated that sediments were moderately polluted with Cu (overall mean: 21.48 +/- 4.76 {mu}g.g-1 dry sediment), but not with Pb (15 +/- 8), Zn (38 +/- 10), Cr (15 +/- 7), Ni (13 +/- 6) and Cd (0.4 +/- 0.2). Depending on location, total petroleum hydrocarbons ranged from 1.6 to 10.6 {mu}g.g-1. To discriminate pattern differences and similarities among samples, principal component analysis (PCA) was performed using a correlation matrix. PCA revealed the latent relationships among all the stations investigated and confirmed our analytical results. Principal components analysis confirmed two regions according to their environmental quality. The results pointed out that almost all the area presented some substances that can cause adverse biological effects, especially in the outermost region where some metals are above TEL level. (author)

Heavy metal leaching from mine tailings as affected by plants

Energy Technology Data Exchange (ETDEWEB)

Zhu, D.; Schwab, A.P.; Banks, M.K.

1999-12-01

A column experiment was conducted to determine the impact of soil cover and plants on heavy metal leaching from mine tailings and heavy metal contaminated soil. Columns made of PVC were constructed with 30 cm subsoil covered by 30 cm of mine tailings followed by 0, 30, or 60 cm subsoil covered by 30 cm of mine tailings followed by 0, 30, or 60 cm of clean topsoil. Two grasses, tall fescue (Festuca arundinacea Schreb.) and big bluestem (Andropogon gerardii), were grown in the columns. The columns were leached at a slow rate for 1 yr with a 0.001 M CaCl{sub 2} solution under unsaturated conditions. The presence of both tall fescue and big bluestem increased Zn and Cd concentrations in the leachate. Lead concentrations in leachates were not affected by the presence of plants. Although plants generally reduced the total amount of water leached, total mass of Zn and Cd leached generally was not impacted by plants. Total mass of Pb leached was positively correlated with total leachate collected from each column. Covering the mine tailings with 60 cm of topsoil increased the mass of Zn and Cd leached relative to no topsoil. When the subsoil was absent, Zn and Cd leaching increased by as much as 20-fold, verifying the ability of soil to act as a sink for metals. Mine tailing remediation by establishing vegetation can reduce Pb movement but may enhance short-term Cd and Zn leaching. However, the changes were relatively small and do not outweigh the benefits of using vegetation in mine tailings reclamation.

General aspects of metal toxicity.

Science.gov (United States)

Kozlowski, H; Kolkowska, P; Watly, J; Krzywoszynska, K; Potocki, S

2014-01-01

This review is focused on the general mechanisms of metal toxicity in humans. The possible and mainly confirmed mechanisms of their action are discussed. The metals are divided into four groups due to their toxic effects. First group comprises of metal ions acting as Fenton reaction catalyst mainly iron and copper. These types of metal ions participate in generation of the reactive oxygen species. Metals such as nickel, cadmium and chromium are considered as carcinogenic agents. Aluminum, lead and tin are involved in neurotoxicity. The representative of the last group is mercury, which may be considered as a generally toxic metal. Fenton reaction is a naturally occurring process producing most active oxygen species, hydroxyl radical: Fe(2+) + He2O2 ↔ Fe(3+) + OH(-) + OH(•) It is able to oxidize most of the biomolecules including DNA, proteins, lipids etc. The effect of toxicity depends on the damage of molecules i.e. production site of the hydroxyl radical. Chromium toxicity depends critically on its oxidation state. The most hazardous seems to be Cr(6+) (chromates) which are one of the strongest inorganic carcinogenic agents. Cr(6+) species act also as oxidative agents damaging among other nucleic acids. Redox inactive Al(3+), Cd(2+) or Hg(2+) may interfere with biology of other metal ions e.g. by occupying metal binding sites in biomolecules. All these aspects will be discussed in the review.

On the road to metallic nanoparticles by rational design: bridging the gap between atomic-level theoretical modeling and reality by total scattering experiments

Science.gov (United States)

Prasai, Binay; Wilson, A. R.; Wiley, B. J.; Ren, Y.; Petkov, Valeri

2015-10-01

The extent to which current theoretical modeling alone can reveal real-world metallic nanoparticles (NPs) at the atomic level was scrutinized and demonstrated to be insufficient and how it can be improved by using a pragmatic approach involving straightforward experiments is shown. In particular, 4 to 6 nm in size silica supported Au100-xPdx (x = 30, 46 and 58) explored for catalytic applications is characterized structurally by total scattering experiments including high-energy synchrotron X-ray diffraction (XRD) coupled to atomic pair distribution function (PDF) analysis. Atomic-level models for the NPs are built by molecular dynamics simulations based on the archetypal for current theoretical modeling Sutton-Chen (SC) method. Models are matched against independent experimental data and are demonstrated to be inaccurate unless their theoretical foundation, i.e. the SC method, is supplemented with basic yet crucial information on the length and strength of metal-to-metal bonds and, when necessary, structural disorder in the actual NPs studied. An atomic PDF-based approach for accessing such information and implementing it in theoretical modeling is put forward. For completeness, the approach is concisely demonstrated on 15 nm in size water-dispersed Au particles explored for bio-medical applications and 16 nm in size hexane-dispersed Fe48Pd52 particles explored for magnetic applications as well. It is argued that when ``tuned up'' against experiments relevant to metals and alloys confined to nanoscale dimensions, such as total scattering coupled to atomic PDF analysis, rather than by mere intuition and/or against data for the respective solids, atomic-level theoretical modeling can provide a sound understanding of the synthesis-structure-property relationships in real-world metallic NPs. Ultimately this can help advance nanoscience and technology a step closer to producing metallic NPs by rational design.The extent to which current theoretical modeling alone can

Effect of heavy metals on the level of vitamin E, total lipid and glycogen reserves in the liver of common carp (Cyprinus carpio L.

Directory of Open Access Journals (Sweden)

Vinodhini Rajamanickam

2008-06-01

Full Text Available The aim of this study is to examine some changes in the biochemical profile of the liver tissue of common carp (Cyprinus carpio L. exposed to a sublethal concentration of heavy metal mixture (cadmium, chromium, nickel and lead. The biochemical profile, specifically glycogen, total lipid and vitamin E content in the liver tissue was examined and compared to that of the control group. The exposed group showed a marked decline in glycogen and vitamin E reserves. Conversely an increase in total lipid in comparison to control was observed. The result reflects the sensitivity of these biochemical parameters to the effects of sublethal levels of combined heavy metals for this the widely consumed freshwater fish.

Monitoring of total metal concentration in sludge samples: Case study for the mechanical–biological wastewater treatment plant in Velika Gorica, Croatia

International Nuclear Information System (INIS)

Filipović, Josip; Grčić, Ivana; Bermanec, Vladimir; Kniewald, Goran

2013-01-01

In this paper, monitoring of total metal concentration in sludge samples from wastewater treatment process is elaborated. The presented results summarize the analyses of sludge samples in a period from 2008 to 2012. Possible sources of pollutions are given. Primarily, waste solid samples were collected from different pretreatment steps: (A) coarse grid, (B) fine grid and (C) aerated sand grease grid. Samples of A and B followed a repeatable pattern in 2008 and 2010. According to the results from 2008, samples of C contained measurable concentration of the following metals (mg/kg dry matter): Zn (21), Ni (1.05) and Ba (14.9). Several types of sludge samples were analyzed: fresh raw sludge (PS; 6–12 hour old), the sludge from the digester for anaerobic sludge treatment (DS; 48–72 hour old), samples from lagoons where the sludge is temporarily deposited (DOS and DOSold; 30–120 days) and sludge samples from agricultural areas (AA; aged over 180 days). Additionally, samples of dehydrated sludge (DEHS and DEHSold; 90–180 days) were collected upon construction of equipment for sludge dehydration in 2011. An analysis of total metal concentrations for Cu, Zn, Cr, Pb, Ni, Hg, Cd, Ba, As, Se, Sb, Co, Mo, Fe and Mn was performed by flame atomic absorption spectrometry (FAAS) and inductively coupled plasma-optical emission spectrometry (ICP-OES). The most recent results (year 2011) indicated a high concentration of heavy metals in PS samples, exceeding the MCLs (mg/kg dry matter): Cu (2122), Zn (5945), Hg (13.67) and Cd (6.29). In 2012 (until July), only a concentration of Cu exceeded MCL (928.75 and 1230.5 in DS and DEHS, respectively). A composition of sludge was variable through time, offering the limited possibility for future prediction. The sludge is being considered as a hazardous waste and a subject of discussion regarding disposal. - Highlights: ► Summarized 5-year monitoring data for heavy metals in sludge ► Partially determined sources of pollution by

Monitoring of total metal concentration in sludge samples: Case study for the mechanical–biological wastewater treatment plant in Velika Gorica, Croatia

Energy Technology Data Exchange (ETDEWEB)

Filipović, Josip [Town Office for Physical Planning and Environmental Protection, Velika Gorica County, Trg kralja Tomislava 34, 10410 Velika Gorica (Croatia); Grčić, Ivana, E-mail: igrcic@fkit.hr [Faculty of Chemical Engineering and Technology, University of Zagreb Marulićev trg 19, 10000 Zagreb (Croatia); Bermanec, Vladimir [Institute of Mineralogy and Petrology, Faculty of Science, University of Zagreb, Horvatovac bb, 10000 Zagreb (Croatia); Kniewald, Goran [Division for Marine and Environmental Research, Ruđer Bošković Institute, Bijenička 54, 10000 Zagreb (Croatia)

2013-03-01

In this paper, monitoring of total metal concentration in sludge samples from wastewater treatment process is elaborated. The presented results summarize the analyses of sludge samples in a period from 2008 to 2012. Possible sources of pollutions are given. Primarily, waste solid samples were collected from different pretreatment steps: (A) coarse grid, (B) fine grid and (C) aerated sand grease grid. Samples of A and B followed a repeatable pattern in 2008 and 2010. According to the results from 2008, samples of C contained measurable concentration of the following metals (mg/kg dry matter): Zn (21), Ni (1.05) and Ba (14.9). Several types of sludge samples were analyzed: fresh raw sludge (PS; 6–12 hour old), the sludge from the digester for anaerobic sludge treatment (DS; 48–72 hour old), samples from lagoons where the sludge is temporarily deposited (DOS and DOSold; 30–120 days) and sludge samples from agricultural areas (AA; aged over 180 days). Additionally, samples of dehydrated sludge (DEHS and DEHSold; 90–180 days) were collected upon construction of equipment for sludge dehydration in 2011. An analysis of total metal concentrations for Cu, Zn, Cr, Pb, Ni, Hg, Cd, Ba, As, Se, Sb, Co, Mo, Fe and Mn was performed by flame atomic absorption spectrometry (FAAS) and inductively coupled plasma-optical emission spectrometry (ICP-OES). The most recent results (year 2011) indicated a high concentration of heavy metals in PS samples, exceeding the MCLs (mg/kg dry matter): Cu (2122), Zn (5945), Hg (13.67) and Cd (6.29). In 2012 (until July), only a concentration of Cu exceeded MCL (928.75 and 1230.5 in DS and DEHS, respectively). A composition of sludge was variable through time, offering the limited possibility for future prediction. The sludge is being considered as a hazardous waste and a subject of discussion regarding disposal. - Highlights: ► Summarized 5-year monitoring data for heavy metals in sludge ► Partially determined sources of pollution by

Heavy Metal Poisoning and Cardiovascular Disease

Directory of Open Access Journals (Sweden)

Eman M. Alissa

2011-01-01

Full Text Available Cardiovascular disease (CVD is an increasing world health problem. Traditional risk factors fail to account for all deaths from CVD. It is mainly the environmental, dietary and lifestyle behavioral factors that are the control keys in the progress of this disease. The potential association between chronic heavy metal exposure, like arsenic, lead, cadmium, mercury, and CVD has been less well defined. The mechanism through which heavy metals act to increase cardiovascular risk factors may act still remains unknown, although impaired antioxidants metabolism and oxidative stress may play a role. However, the exact mechanism of CVD induced by heavy metals deserves further investigation either through animal experiments or through molecular and cellular studies. Furthermore, large-scale prospective studies with follow up on general populations using appropriate biomarkers and cardiovascular endpoints might be recommended to identify the factors that predispose to heavy metals toxicity in CVD. In this review, we will give a brief summary of heavy metals homeostasis, followed by a description of the available evidence for their link with CVD and the proposed mechanisms of action by which their toxic effects might be explained. Finally, suspected interactions between genetic, nutritional and environmental factors are discussed.

Bioaccumulation of trace metals and total petroleum and genotoxicity responses in an edible fish population as indicators of marine pollution.

Science.gov (United States)

D'Costa, Avelyno; Shyama, S K; Praveen Kumar, M K

2017-08-01

The present study reports the genetic damage and the concentrations of trace metals and total petroleum hydrocarbons prevailing in natural populations of an edible fish, Arius arius in different seasons along the coast of Goa, India as an indicator of the pollution status of coastal water. Fish were collected from a suspected polluted site and a reference site in the pre-monsoon, monsoon and post-monsoon seasons. Physico-chemical parameters as well as the concentrations of total petroleum hydrocarbons (TPH) and trace metals in the water and sediment as well as the tissues of fish collected from these sites were recorded. The genotoxicity status of the fish was assessed employing the micronucleus test and comet assay. A positive correlation (p<0.001) was observed between the tail DNA and micronuclei in all the fish collected. Multiple regression analysis revealed that tissue and environmental pollutant concentrations and genotoxicity were positively associated and higher in the tissues of the fish collected from the polluted site. Pollution indicators and genotoxicity tests, combined with other physiological or biochemical parameters represent an essential integrated approach for efficient monitoring of aquatic ecosystems in Goa. Copyright © 2017 Elsevier Inc. All rights reserved.

Subcellular partitioning of metals in Aporrectodea caliginosa along a gradient of metal exposure in 31 field-contaminated soils

Energy Technology Data Exchange (ETDEWEB)

Beaumelle, Léa [INRA, UR 251 PESSAC, 78026 Versailles Cedex (France); Gimbert, Frédéric [Laboratoire Chrono-Environnement, UMR 6249 University of Franche-Comté/CNRS Usc INRA, 16 route de Gray, 25030 Besançon Cedex (France); Hedde, Mickaël [INRA, UR 251 PESSAC, 78026 Versailles Cedex (France); Guérin, Annie [INRA, US 0010 LAS Laboratoire d' analyses des sols, 273 rue de Cambrai, 62000 Arras (France); Lamy, Isabelle, E-mail: lamy@versailles.inra.fr [INRA, UR 251 PESSAC, 78026 Versailles Cedex (France)

2015-07-01

Subcellular fractionation of metals in organisms was proposed as a better way to characterize metal bioaccumulation. Here we report the impact of a laboratory exposure to a wide range of field-metal contaminated soils on the subcellular partitioning of metals in the earthworm Aporrectodea caliginosa. Soils moderately contaminated were chosen to create a gradient of soil metal availability; covering ranges of both soil metal contents and of several soil parameters. Following exposure, Cd, Pb and Zn concentrations were determined both in total earthworm body and in three subcellular compartments: cytosolic, granular and debris fractions. Three distinct proxies of soil metal availability were investigated: CaCl{sub 2}-extractable content dissolved content predicted by a semi-mechanistic model and free ion concentration predicted by a geochemical speciation model. Subcellular partitionings of Cd and Pb were modified along the gradient of metal exposure, while stable Zn partitioning reflected regulation processes. Cd subcellular distribution responded more strongly to increasing soil Cd concentration than the total internal content, when Pb subcellular distribution and total internal content were similarly affected. Free ion concentrations were better descriptors of Cd and Pb subcellular distribution than CaCl{sub 2} extractable and dissolved metal concentrations. However, free ion concentrations and soil total metal contents were equivalent descriptors of the subcellular partitioning of Cd and Pb because they were highly correlated. Considering lowly contaminated soils, our results raise the question of the added value of three proxies of metal availability compared to soil total metal content in the assessment of metal bioavailability to earthworm. - Highlights: • Earthworms were exposed to a wide panel of historically contaminated soils • Subcellular partitioning of Cd, Pb and Zn was investigated in earthworms • Three proxies of soil metal availability were

Relationship between metal speciation in soil solution and metal adsorption at the root surface of ryegrass.

Science.gov (United States)

Kalis, Erwin J J; Temminghoff, Erwin J M; Town, Raewyn M; Unsworth, Emily R; van Riemsdijk, Willem H

2008-01-01

The total metal content of the soil or total metal concentration in the soil solution is not always a good indicator for metal availability to plants. Therefore, several speciation techniques have been developed that measure a defined fraction of the total metal concentration in the soil solution. In this study the Donnan Membrane Technique (DMT) was used to measure free metal ion concentrations in CaCl(2) extractions (to mimic the soil solution, and to work under standardized conditions) of 10 different soils, whereas diffusive gradients in thin-films (DGT) and scanning chronopotentiometry (SCP) were used to measure the sum of free and labile metal concentrations in the CaCl(2) extracts. The DGT device was also exposed directly to the (wetted) soil (soil-DGT). The metal concentrations measured with the speciation techniques are related to the metal adsorption at the root surface of ryegrass (Lolium perenne L.), to be able to subsequently predict metal uptake. In most cases the metal adsorption related pH-dependently to the metal concentrations measured by DMT, SCP, and DGT in the CaCl(2) extract. However, the relationship between metal adsorption at the root surface and the metal concentrations measured by the soil-DGT was not-or only slightly-pH dependent. The correlations between metal adsorption at the root surface and metal speciation detected by different speciation techniques allow discussion about rate limiting steps in biouptake and the contribution of metal complexes to metal bioavailability.

Leaching Properties of Naturally Occurring Heavy Metals from Soils

Science.gov (United States)

Zhang, M.; Hoshino, M.; Yoshikawa, M.; Hara, J.; Sugita, H.

2014-12-01

The major threats to human health from heavy metals are associated with exposure to arsenic, lead, cadmium, chromium, mercury, as well as some other elements. The effects of such heavy metals on human health have been extensively studied and reviewed by international organizations such as WHO. Due to their toxicity, heavy metal contaminations have been regulated by national environmental standards in many countries, and/or laws such as the Soil Contamination Countermeasures Act in Japan. Leaching of naturally occurring heavy metals from the soils, especially those around abandoned metal mines into surrounding water systems, either groundwater or surface water systems, is one of the major pathways of exposure. Therefore, understanding the leaching properties of toxic heavy metals from naturally polluted soils is of fundamentally importance for effectively managing abandoned metal mines, excavated rocks discharged from infrastructure constructions such as tunneling, and/or selecting a pertinent countermeasure against pollution when it is necessary. In this study, soil samples taken from the surroundings of abandoned metal mines in different regions in Japan were collected and analyzed. The samples contained multiple heavy metals such as lead, arsenic and chromium. Standard leaching test and sequential leaching test considering different forms of contaminants, such as trivalent and pentavalent arsenics, and trivalent and hexavalent chromiums, together with standard test for evaluating total concentration, X-ray Fluorescence Analysis (XRF), X-ray diffraction analysis (XRD) and Cation Exchange Capacity (CEC) tests were performed. In addition, sequential leaching tests were performed to evaluate long-term leaching properties of lead from representative samples. This presentation introduces the details of the above experimental study, discusses the relationships among leaching properties and chemical and mineral compositions, indicates the difficulties associated with

Winter-time size distribution and source apportionment of total suspended particulate matter and associated metals in Delhi

Science.gov (United States)

Srivastava, Arun; Gupta, Sandeep; Jain, V. K.

2009-03-01

A study of the winter time size distribution and source apportionment of total suspended particulate matter (TSPM) and associated heavy metal concentrations have been carried out for the city of Delhi. This study is important from the point of view of implementation of compressed natural gas (CNG) as alternate of diesel fuel in the public transport system in 2001 to reduce the pollution level. TSPM were collected using a five-stage cascade impactor at six sites in the winters of 2005-06. The results of size distribution indicate that a major portion (~ 40%) of TSPM concentration is in the form of PM0.7 (heavy metals associated with various size fractions of TSPM. A very good correlation between coarse and fine size fraction of TSPM was observed. It was also observed that the metals associated with coarse particles have more chances of correlation with other metals; rather they are associated with fine particles. Source apportionment was carried out separately in coarse and fine size modes of TSPM by Chemical Mass Balance Receptor Model (CMB8) as well as by Principle Component Analysis (PCA) of SPSS. Source apportionment by PCA reveals that there are two major sources (possibly vehicular and crustal re-suspension) in both coarse and fine size fractions. Results obtained by CMB8 show the dominance of vehicular pollutants and crustal dust in fine and coarse size mode respectively. Noticeably the dominance of vehicular pollutants are now confined to fine size only whilst during pre CNG era it dominated both coarse and fine size mode. An increase of 42.5, 44.4, 48.2, 38.6 and 38.9% in the concentrations of TSPM, PM10.9, coarse particles, fine particles and lead respectively was observed during pre (2001) to post CNG (2005-06) period.

Bearing Change to Metal-On-Polyethylene for Ceramic Bearing Fracture in Total Hip Arthroplasty; Does It Work?

Science.gov (United States)

Lee, Soong Joon; Kwak, Hong Suk; Yoo, Jeong Joon; Kim, Hee Joong

2016-01-01

We evaluated the short-term to midterm results of reoperation with bearing change to metal-on-polyethylene (MoP) after ceramic bearing fracture in ceramic-on-ceramic total hip arthroplasty. Nine third-generation ceramic bearing fractures (6 heads and 3 liners) were treated with bearing change to MoP. Mean age at reoperation was 52.7 years. Mean follow-up was 4.3 years. During follow-up, 2 of 3 liner-fractured hips and 1 of 6 head-fractured hips showed radiologic signs of metallosis and elevated serum chromium levels. Re-reoperation with bearing rechange to a ceramic head was performed for the hips with metallosis. One liner-fractured hip had periprosthetic joint infection. Dislocation occurred in 3 hips. From our experience, bearing change to MoP is not a recommended treatment option for ceramic bearing fracture in total hip arthroplasty. Copyright © 2016 Elsevier Inc. All rights reserved.

Urbanization increased metal levels in lake surface sediment and catchment topsoil of waterscape parks

Energy Technology Data Exchange (ETDEWEB)

Li, Hong-Bo [Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021 (China); Graduate University of Chinese Academy of Sciences, Beijing 100049 (China); Yu, Shen, E-mail: syu@iue.ac.cn [Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021 (China); Li, Gui-Lin [Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021 (China); Liu, Yi; Yu, Guang-Bin [Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021 (China); Graduate University of Chinese Academy of Sciences, Beijing 100049 (China); Deng, Hong [Department of Environmental Sciences, Tiantong National Station of Forest Ecosystem, Key Laboratory of Urbanization and Ecological Restoration, East China Normal University, Shanghai 200062 (China); Wu, Sheng-Chun [State Key Laboratory in Marine Pollution, Biology and Chemistry Department, City University of Hong Kong, Hong Kong (China); Wong, Ming-Hung [Croucher Institute for Environmental Sciences, Hong Kong Baptist University, Hong Kong (China)

2012-08-15

Lake surface sediment is mainly derived from topsoil in its catchment. We hypothesized that distribution of anthropogenic metals would be homogenous in lake surface sediment and the lake's catchment topsoil. Anthropogenic metal distributions (cadmium (Cd), copper (Cu), lead (Pb), and zinc (Zn)) in fourteen waterscape parks were investigated in surface sediments and catchment topsoils and possible source homogeneity was tested using stable Pb isotopic ratio analysis. The parks were located along an urbanization gradient consisting of suburban (SU), developing urban (DIU), developed urban (DDU), and central urban core (CUC) areas in Shanghai, China. Results indicated that surface lake sediments and catchment topsoils in the CUC parks were highly contaminated by the investigated anthropogenic metals. Total metal contents in surface sediment and topsoil gradually increased along the urbanization gradient from the SU to CUC areas. Generally, the surface sediments had greater total metal contents than their catchment topsoils. These results suggest that urbanization drives the anthropogenic metal enrichment in both surface sediment and its catchment topsoil in the waterscape parks. Soil fine particles (< 63 {mu}m) and surface sediments had similar enrichment ratios of metals, suggesting that surface runoff might act as a carrier for metals transporting from catchment to lake. Stable Pb isotope ratio analysis revealed that the major anthropogenic Pb source in surface sediment was coal combustion as in the catchment topsoil. Urbanization also correlated with chemical fractionation of metals in both surface sediment and catchment topsoil. From the SU to the CUC parks, amounts of labile metal fractions increased while the residual fraction of those metals remained rather constant. In short, urbanization in Shanghai drives anthropogenic metal distribution in environmental matrices and the sources were homogenous. -- Highlights: Black-Right-Pointing-Pointer Obvious

Urbanization increased metal levels in lake surface sediment and catchment topsoil of waterscape parks

International Nuclear Information System (INIS)

Li, Hong-Bo; Yu, Shen; Li, Gui-Lin; Liu, Yi; Yu, Guang-Bin; Deng, Hong; Wu, Sheng-Chun; Wong, Ming-Hung

2012-01-01

Lake surface sediment is mainly derived from topsoil in its catchment. We hypothesized that distribution of anthropogenic metals would be homogenous in lake surface sediment and the lake's catchment topsoil. Anthropogenic metal distributions (cadmium (Cd), copper (Cu), lead (Pb), and zinc (Zn)) in fourteen waterscape parks were investigated in surface sediments and catchment topsoils and possible source homogeneity was tested using stable Pb isotopic ratio analysis. The parks were located along an urbanization gradient consisting of suburban (SU), developing urban (DIU), developed urban (DDU), and central urban core (CUC) areas in Shanghai, China. Results indicated that surface lake sediments and catchment topsoils in the CUC parks were highly contaminated by the investigated anthropogenic metals. Total metal contents in surface sediment and topsoil gradually increased along the urbanization gradient from the SU to CUC areas. Generally, the surface sediments had greater total metal contents than their catchment topsoils. These results suggest that urbanization drives the anthropogenic metal enrichment in both surface sediment and its catchment topsoil in the waterscape parks. Soil fine particles (< 63 μm) and surface sediments had similar enrichment ratios of metals, suggesting that surface runoff might act as a carrier for metals transporting from catchment to lake. Stable Pb isotope ratio analysis revealed that the major anthropogenic Pb source in surface sediment was coal combustion as in the catchment topsoil. Urbanization also correlated with chemical fractionation of metals in both surface sediment and catchment topsoil. From the SU to the CUC parks, amounts of labile metal fractions increased while the residual fraction of those metals remained rather constant. In short, urbanization in Shanghai drives anthropogenic metal distribution in environmental matrices and the sources were homogenous. -- Highlights: ► Obvious urbanization effect on metal

What fraction of the total metal flux into lakes is retained in the sediments

Energy Technology Data Exchange (ETDEWEB)

Nriagu, J O; Wong, H K.T.

1986-12-01

The concentrations of, and deposition rates for, the pollutant metals (Pb, Cu, Zn, Ni, and Cd) and the rare earth elements are reported for the sediments and settling particulates in a large, remote lake (Lake Opeongo) in the Algonquin Provincial Park, Ontario. Using a mass conservation model based on the rare earth elements, it is estimated that only 40 to 60% of pollutant metals getting into the lake is retained by the sediments. The low retention rate may explain the widely reported intrabasin and intra-lake differences in metal contents of sediments and casts some doubt on the use of pollutant metal profiles in retrospective assessment of the human contribution to the metal flux into many lake basins. 22 references.

Phytoremediation of metals using lemongrass (Cymbopogon citratus (D.C.) Stapf.) grown under different levels of red mud in soil amended with biowastes.

Science.gov (United States)

Gautam, Meenu; Pandey, Divya; Agrawal, Madhoolika

2017-06-03

Due to hostile condition of red mud (RM), its utilization for vegetation is restricted. Therefore, RM with biowastes as soil amendment may offer suitable combination to support plant growth with reduced risk of metal toxicity. To evaluate the effects of RM on soil properties, plant growth performance, and metal accumulation in lemongrass, a study was conducted using different RM concentrations (0, 5, 10, and 15% w/w) in soil amended with biowastes [cow dung manure (CD) or sewage-sludge (SS)]. Application of RM in soil with biowastes improved organic matter and nutrient contents and caused reduction in phytoavailable metal contents. Total plant biomass was increased under all treatments, maximally at 5% RM in soil with SS (91.4%) and CD (51.7%) compared to that in control (no RM and biowastes). Lemongrass acted as a potential metal-tolerant plant as its metal tolerance index is >100%. Based on translocation and bioconcentration factors, lemongrass acted as a potential phytostabilizer of Fe, Mn, and Cu in roots and was found efficient in translocation of Al, Zn, Cd, Pb, Cr, As, and Ni from roots to shoot. The study suggests that 5% RM with biowastes preferably SS may be used to enhance phytoremediation potential of lemongrass.

Determination of platinum group metal catalyst residues in active pharmaceutical ingredients by means of total reflection X-ray spectrometry

International Nuclear Information System (INIS)

Marguí, Eva; Queralt, Ignasi; Hidalgo, Manuela

2013-01-01

The control of metal catalyst residues (i.e., platinum group metals (PGMs)) in different stages of the manufacturing processes of the active pharmaceutical ingredients (APIs) and, especially, in the final product is crucial. For API specimens, there are strict guidelines to limit the levels of metal residues based on their individual levels of safety concern. For PGMs the concentration limit has been established at 10 mg/kg in the API. Therefore great effort is currently being devoted to the development of new and simple procedures to control metals in pharmaceuticals. In the present work, an analytical methodology based on benchtop total reflection X-ray fluorescence spectrometry (TXRF) has been developed for the rapid and simple determination of some PGM catalyst impurities (Rh, Pd, Ir and Pt) in different types of API samples. An evaluation of different sample treatments (dissolution and digestion of the solid pharmaceutical samples) has been carried out and the developed methodologies have been validated according to the analytical parameters to be considered and acceptance criteria for PGM determination according to the United States Pharmacopeia (USP). Limits of quantification obtained for PGM metals were in the range of 2–4 mg/kg which are satisfactory according to current legislation. From the obtained results it is shown that the developed TXRF method can be implemented in the pharmaceutical industries to increase productivity of the laboratory; offering an interesting and complementary analytical tool to other atomic spectroscopic methods. - Highlights: • A TXRF method for PGM catalyst residue determination in API samples is presented. • Analysis can be performed using 10 μL of the internal standardized dissolved API. • The method is rapid, simple and suitable according to the USP requirements

Does Choice of Head Size and Neck Geometry Affect Stem Migration in Modular Large-Diameter Metal-on-Metal Total Hip Arthroplasty? A Preliminary Analysis.

Science.gov (United States)

Georgiou, Cs; Evangelou, Kg; Theodorou, Eg; Provatidis, Cg; Megas, Pd

2012-01-01

Due to their theoretical advantages, hip systems combining modular necks and large diameter femoral heads have gradually gained popularity. However, among others, concerns regarding changes in the load transfer patterns were raised. Recent stress analyses have indeed shown that the use of modular necks and big femoral heads causes significant changes in the strain distribution along the femur. Our original hypothesis was that these changes may affect early distal migration of a modular stem. We examined the effect of head diameter and neck geometry on migration at two years of follow-up in a case series of 116 patients (125 hips), who have undergone primary Metal-on-Metal total hip arthroplasty with the modular grit-blasted Profemur®E stem combined with large-diameter heads (>36 mm). We found that choice of neck geometry and head diameter has no effect on stem migration. A multivariate regression analysis including the potential confounding variables of the body mass index, bone quality, canal fill and stem positioning revealed only a negative correlation between subsidence and canal fill in midstem area. Statistical analysis, despite its limitations, did not confirm our hypothesis that choice of neck geometry and/or head diameter affects early distal migration of a modular stem. However, the importance of correct stem sizing was revealed.

Metal-enhanced galactic winds. I

International Nuclear Information System (INIS)

Vader, J.P.

1986-01-01

Supernova-driven gas loss during the early evolution of elliptical galaxies is considered as a possible explanation for the correlations among the observed chemical and structural properties of these systems. Mass loss from systems with a chemically homogeneous interstellar medium does not work. It is pointed out that supernova-driven winds are in fact metal-enhanced with respect to the star-forming gas because the metal production of any supernova that drives the wind is directly flushed out of the galaxy. The fraction of the total metal production lost in the wind is thus at least as large as the fraction epsilon(z) of supernovae that power the wind, independent of the total mass loss. As a corollary, the yield of heavy elements that are recycled in the galaxy is reduced by a factor 1 - epsilon(z). Metal-enhanced galactic winds, which can carry away a large fraction of the metal production in spite of a moderate total mass loss, offer a promising explanation for the low metallicities of dwarf elliptical galaxies. 62 references

The risk assessment of heavy metals in Futian mangrove forest sediment in Shenzhen Bay (South China) based on SEM-AVS analysis.

Science.gov (United States)

Chai, Minwei; Shen, Xiaoxue; Li, Ruili; Qiu, Guoyu

2015-08-15

The risks of heavy metal in Futian mangrove forest sediment were assessed using the acid-volatile sulfide (AVS) and simultaneously extracted metals (SEM) methods. The results indicated that AVS distributions were more variable than the SEM distributions at all 16 sampling sites. The positive correlation between AVS and SEM indicated that their similar formative and existing conditions and that AVS acted as an important carrier for SEM. The major SEM component was Zn (69.7.3-94.2%), whereas the Cd contribution (the most toxic metal present) to SEM was no more than 1%. The possible adverse effects caused by heavy metals at ten sampling sites may be due to higher levels of SEMs, rather than AVSs. The total organic carbon (TOC) was an important metal-binding phase in the sediments. Taking into account the TOC concentration, there were no adverse effects due to heavy metals in any of the Futian mangrove forest sediments. Copyright © 2015 Elsevier Ltd. All rights reserved.

Method for electrolytic decontamination of radioactive contaminated metals

International Nuclear Information System (INIS)

Tanaka, Akio; Horita, Masami; Onuma, Tsutomu; Kato, Koji

1991-01-01

The invention relates to an electrolytic decontamination method for radioactive contaminated metals. The contaminated sections are eluted by electrolysis after the surface of a piece of equipment used with radioactive substances has been immersed in an electrolyte. Metal contaminated by radioactive substances acts as the anode

Comparative study of material loss at the taper interface in retrieved metal-on-polyethylene and metal-on-metal femoral components from a single manufacturer.

Science.gov (United States)

Bills, Paul; Racasan, Radu; Bhattacharya, Saugatta; Blunt, Liam; Isaac, Graham

2017-08-01

There have been a number of reports on the occurrence of taper corrosion and/or fretting and some have speculated on a link to the occurrence of adverse local tissue reaction specifically in relation to total hip replacement which have a metal-on-metal bearing. As such a study was carried out to compare the magnitude of material loss at the taper in a series of retrieved femoral heads used in metal-on-polyethylene bearings with that in a series of retrieved heads used in metal-on-metal bearings. A total of 36 metal-on-polyethylene and 21 metal-on-metal femoral components were included in the study all of which were received from a customer complaint database. Furthermore, a total of nine as-manufactured femoral components were included to provide a baseline for characterisation. All taper surfaces were assessed using an established corrosion scoring method and measurements were taken of the female taper surface using a contact profilometry. In the case of metal-on-metal components, the bearing wear was also assessed using coordinate metrology to determine whether or not there was a relationship between bearing and taper material loss in these cases. The study found that in this cohort the median value of metal-on-polyethylene taper loss was 1.25 mm 3 with the consequent median value for metal-on-metal taper loss being 1.75 mm 3 . This study also suggests that manufacturing form can result in an apparent loss of material from the taper surface determined to have a median value of 0.59 mm 3 . Therefore, it is clear that form variability is a significant confounding factor in the measurement of material loss from the tapers of femoral heads retrieved following revision surgery.

Determination of metals by total reflection X-ray fluorescence and evaluation of toxicity of a river impacted by coal mining in the south of Brazil.

Science.gov (United States)

Lattuada, R M; Menezes, C T B; Pavei, P T; Peralba, M C R; Dos Santos, J H Z

2009-04-30

Metal (Fe, Mn, Zn, Ni, Cd, and Pb) concentrations in the region of Criciuma (Brazil), a region impacted by coal mining, were determined in water and sediments using total reflection X-ray fluorescence (TXRF) spectroscopy. Samples were collected from the Mãe Luzia River (south Brazil) at five different stations, from the source down to the river mouth (Ararangua estuary). Water and sediment toxicity were also evaluated using bioassays with Daphnia magna as the bioindicator. The metal present in the highest concentrations both in water (1.3-11 mg L(-1)) and in sediments (34-142 mg L(-1)) was iron. Results suggest an influence of coal mining on the aquatic receptors, showing a clear relationship between metal content (mostly Fe) and ecotoxicity.

Resource Conservation and Recovery Act, Part B Permit Application

International Nuclear Information System (INIS)

1991-02-01

The Waste Isolation Pilot Plant (WIPP) project was authorized by the Department of Energy National Security and Military Applications of Nuclear Energy Authorization Act of 1980 (Public Law 96-164) as a research and development facility to demonstrate the safe, environmentally sound disposal of transuranic (TRU) radioactive wastes derived from the defense activities of the United States. The WIPP facility is owned and operated by the US Department of Energy (DOE). The TRU waste to be received at WIPP consists largely of such items as laboratory glassware and utensils, tools, scrap metal, shielding, personnel protection equipment, and solidified sludges from the treatment of waste water. Approximately 60 percent of this waste is ''mixed,'' that is, it is also contaminated with hazardous waste or hazardous waste constituents as defined by the Resource Conservation and Recovery Act (RCRA) and by the New Mexico Hazardous Waste Management Regulations (HWMR-5). Therefore, emplacement of TRU mixed waste in the WIPP repository is subject to regulation under HWMR-5 and RCRA. The permit application under the Resource Conservation and Recovery Act for WIPP is divided into five volumes. This document, Volume 2, contains Appendices B1, C1, and C2. These appendices describe the surface hydrology of the area, provide a description of the physical and chemical characteristics of wastes to be placed in WIPP, and outline a waste analysis plan which gives an overview of the total waste inventory planned for WIPP. 34 refs., 107 figs., 27 tabs

Traversing the Links between Heavy Metal Stress and Plant Signaling

Science.gov (United States)

Jalmi, Siddhi K.; Bhagat, Prakash K.; Verma, Deepanjali; Noryang, Stanzin; Tayyeba, Sumaira; Singh, Kirti; Sharma, Deepika; Sinha, Alok K.

2018-01-01

Plants confront multifarious environmental stresses widely divided into abiotic and biotic stresses, of which heavy metal stress represents one of the most damaging abiotic stresses. Heavy metals cause toxicity by targeting crucial molecules and vital processes in the plant cell. One of the approaches by which heavy metals act in plants is by over production of reactive oxygen species (ROS) either directly or indirectly. Plants act against such overdose of metal in the environment by boosting the defense responses like metal chelation, sequestration into vacuole, regulation of metal intake by transporters, and intensification of antioxidative mechanisms. This response shown by plants is the result of intricate signaling networks functioning in the cell in order to transmit the extracellular stimuli into an intracellular response. The crucial signaling components involved are calcium signaling, hormone signaling, and mitogen activated protein kinase (MAPK) signaling that are discussed in this review. Apart from signaling components other regulators like microRNAs and transcription factors also have a major contribution in regulating heavy metal stress. This review demonstrates the key role of MAPKs in synchronously controlling the other signaling components and regulators in metal stress. Further, attempts have been made to focus on metal transporters and chelators that are regulated by MAPK signaling. PMID:29459874

Insights into aquatic toxicities of the antibiotics oxytetracycline and ciprofloxacin in the presence of metal: Complexation versus mixture

International Nuclear Information System (INIS)

Zhang Yu; Cai Xiyun; Lang Xianming; Qiao Xianliang; Li Xuehua; Chen Jingwen

2012-01-01

Co-contamination of ligand-like antibiotics (e.g., tetracyclines and quinolones) and heavy metals prevails in the environment, and thus the complexation between them is involved in environmental risks of antibiotics. To understand toxicological significance of the complex, effects of metal coordination on antibiotics' toxicity were investigated. The complexation of two antibiotics, oxytetracycline and ciprofloxacin, with three heavy metals, copper, zinc, and cadmium, was verified by spectroscopic techniques. The antibiotics bound metals via multiple coordination sites and rendered a mixture of various complexation speciations. Toxicity analysis indicated that metal coordination did modify the toxicity of the antibiotics and that antibiotic, metal, and their complex acted primarily as concentration addition. Comparison of EC 50 values revealed that the complex commonly was highest toxic and predominately correlated in toxicity to the mixture. Finally, environmental scenario analysis demonstrated that ignoring complexation would improperly classify environmental risks of the antibiotics. - Highlights: ► The complex of antibiotic with metal is a mixture of various complexation modes. ► Antibiotic and metal act as various combined interactions when their complexation is ignored. ► Antibiotic, metal, and their complex act as concentration addition interaction. ► Complex commonly is the highest toxicant. ► Neglecting complexation renders improper classification of risks for antibiotics. - Antibiotic, heavy metal and their complex act primarily as concentration addition interaction and the complex commonly is highest toxic.

Technique for joining metal tubing

Science.gov (United States)

Wright, H. W.

1976-01-01

Uniform wall thickness and uninterrupted heat transfer is achieved by using shaped metal insert as wall material for joint. Insert acts as support during brazing, after which excess material is ground away to bring joint to original tubing size.

Piezoelectric ceramic-reinforced metal matrix composites

OpenAIRE

2004-01-01

Composite materials comprising piezoelectric ceramic particulates dispersed in a metal matrix are capable of vibration damping. When the piezoelectric ceramic particulates are subjected to strain, such as the strain experienced during vibration of the material, they generate an electrical voltage that is converted into Joule heat in the surrounding metal matrix, thereby dissipating the vibrational energy. The piezoelectric ceramic particulates may also act as reinforcements to improve the mec...

Effects of conversion of mangroves into gei wai ponds on sediment heavy metals accumulation in tidal flat estuary, South China

Science.gov (United States)

Li, R.; Qiu, G.; Chai, M.; Li, R.

2017-12-01

Gei wai ponds act as important component in mangrove ecosystem, but the conversion of mangroves into gei wai ponds and its ecological function on heavy metal accumulation is still not clear. The study quantified the sediment heavy metal concentration and speciation in gei wai pond, Avicennia marina marsh and mudflat in Futian mangrove wetlands, South China. The results showed that gei wai pond acidified the sediment and reduced its fertility due to reduced pH, electronic conductivity (EC) and total organic carbon (TOC) compared to A. marina marsh and mudflat. The concentrations of Cd, Cu, Zn and Pb at all depth in gei wai pond sediment were also lower than other sites, indicating reduced storage function on heavy metals. Multiple analysis implied that heavy metals in all sites could be attributed to anthropogenic sources, with Cr as natural and anthropogenic sources in gei wai pond. Gei wai pond sediment had lower heavy metal pollution based on multiple evaluation methods, including potential ecological risk coefficient (Eir), potential ecological risk index (RI), geo-accumulation index (Igeo), mean PEL quotients (m-PEL-q), pollution load index (PLI), mean ERM quotients (m-ERM-q) and total toxic unit (∑TU). Heavy metal speciation analysis indicated that gei wai pond improved the conversion from the immobilized Cd and Cr to the mobilized fraction. SEM-AVS analysis indicated no adverse toxicity occurred in all sites, and the role of TOC in relieving sediment heavy metal toxicity of gei wai pond is limited.

40 CFR 721.4660 - Alcohol, alkali metal salt.

Science.gov (United States)

2010-07-01

... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Alcohol, alkali metal salt. 721.4660 Section 721.4660 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) TOXIC SUBSTANCES CONTROL ACT SIGNIFICANT NEW USES OF CHEMICAL SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.4660 Alcohol, alkali metal sal...

The relationship of metals, bifenthrin, physical habitat metrics, grain size, total organic carbon, dissolved oxygen and conductivity to Hyalella sp. abundance in urban California streams.

Science.gov (United States)

Hall, Lenwood W; Anderson, Ronald D

2013-01-01

The objectives of this study were to determine the relationship between Hyalella sp. abundance in four urban California streams and the following parameters: (1) 8 bulk metals (As, Cd, Cr, Cu, Pb, Hg, Ni, and Zn) and their associated sediment Threshold Effect Levels (TELs); (2) bifenthrin sediment concentrations; (3) 10 habitat metrics and total score; (4) grain size (% sand, silt and clay); (5) Total Organic Carbon (TOC); (6) dissolved oxygen; and (7) conductivity. California stream data used for this study were collected from Kirker Creek (2006 and 2007), Pleasant Grove Creek (2006, 2007 and 2008), Salinas streams (2009 and 2010) and Arcade Creek (2009 and 2010). Hyalella abundance in the four California streams generally declined when metals concentrations were elevated beyond the TELs. There was also a statistically significant negative relationship between Hyalella abundance and % silt for these 4 California streams as Hyalella were generally not present in silt areas. No statistically significant relationships were reported between Hyalella abundance and metals concentrations, bifenthrin concentrations, habitat metrics, % sand, % clay, TOC, dissolved oxygen and conductivity. The results from this study highlight the complexity of assessing which factors are responsible for determining the abundance of amphipods, such as Hyalella sp., in the natural environment.

Measuring hypoxia induced metal release from highly contaminated estuarine sediments during a 40 day laboratory incubation experiment

Energy Technology Data Exchange (ETDEWEB)

Banks, Joanne L., E-mail: jlbanks@student.unimelb.edu.au [Department of Zoology, University of Melbourne, Victoria, 3010 Australia (Australia); Ross, D. Jeff, E-mail: Jeff.Ross@utas.edu.au [Institute of Marine and Antarctic Studies, Nubeena Crescent, Taroona, Tasmania, 7053 Australia (Australia); Keough, Michael J., E-mail: mjkeough@unimelb.edu.au [Department of Zoology, University of Melbourne, Victoria, 3010 Australia (Australia); Eyre, Bradley D., E-mail: bradley.eyre@scu.edu.au [Centre for Coastal Biogeochemistry, School of Environmental Science and Management, Southern Cross University, PO Box 157, Lismore, NSW, 2480 Australia (Australia); Macleod, Catriona K., E-mail: Catriona.Macleod@utas.edu.au [Institute of Marine and Antarctic Studies, Nubeena Crescent, Taroona, Tasmania, 7053 Australia (Australia)

2012-03-15

Nutrient inputs to estuarine and coastal waters worldwide are increasing and this in turn is increasing the prevalence of eutrophication and hypoxic and anoxic episodes in these systems. Many urbanised estuaries are also subject to high levels of anthropogenic metal contamination. Environmental O{sub 2} levels may influence whether sediments act as sinks or sources of metals. In this study we investigated the effect of an extended O{sub 2} depletion event (40 days) on fluxes of trace metals (and the metalloid As) across the sediment-water interface in sediments from a highly metal contaminated estuary in S.E. Tasmania, Australia. We collected sediments from three sites that spanned a range of contamination and measured total metal concentration in the overlying water using sealed core incubations. Manganese and iron, which are known to regulate the release of other divalent cations from sub-oxic sediments, were released from sediments at all sites as hypoxia developed. In contrast, the release of arsenic, cadmium, copper and zinc was comparatively low, most likely due to inherent stability of these elements within the sediments, perhaps as a result of their refractory origin, their association with fine-grained sediments or their being bound in stable sulphide complexes. Metal release was not sustained due to the powerful effect of metal-sulphide precipitation of dissolved metals back into sediments. The limited mobilisation of sediment bound metals during hypoxia is encouraging, nevertheless the results highlight particular problems for management in areas where hypoxia might occur, such as the release of metals exacerbating already high loads or resulting in localised toxicity. - Highlights: Black-Right-Pointing-Pointer Metal contaminated sediments exposed to long-term hypoxia released Mn and Fe pulses. Black-Right-Pointing-Pointer As flux increased under anoxic conditions Cd, Cu and Zn fluxes occurred only during the first week of hypoxia. Black

Measuring hypoxia induced metal release from highly contaminated estuarine sediments during a 40 day laboratory incubation experiment

International Nuclear Information System (INIS)

Banks, Joanne L.; Ross, D. Jeff; Keough, Michael J.; Eyre, Bradley D.; Macleod, Catriona K.

2012-01-01

Nutrient inputs to estuarine and coastal waters worldwide are increasing and this in turn is increasing the prevalence of eutrophication and hypoxic and anoxic episodes in these systems. Many urbanised estuaries are also subject to high levels of anthropogenic metal contamination. Environmental O 2 levels may influence whether sediments act as sinks or sources of metals. In this study we investigated the effect of an extended O 2 depletion event (40 days) on fluxes of trace metals (and the metalloid As) across the sediment–water interface in sediments from a highly metal contaminated estuary in S.E. Tasmania, Australia. We collected sediments from three sites that spanned a range of contamination and measured total metal concentration in the overlying water using sealed core incubations. Manganese and iron, which are known to regulate the release of other divalent cations from sub-oxic sediments, were released from sediments at all sites as hypoxia developed. In contrast, the release of arsenic, cadmium, copper and zinc was comparatively low, most likely due to inherent stability of these elements within the sediments, perhaps as a result of their refractory origin, their association with fine-grained sediments or their being bound in stable sulphide complexes. Metal release was not sustained due to the powerful effect of metal-sulphide precipitation of dissolved metals back into sediments. The limited mobilisation of sediment bound metals during hypoxia is encouraging, nevertheless the results highlight particular problems for management in areas where hypoxia might occur, such as the release of metals exacerbating already high loads or resulting in localised toxicity. - Highlights: ► Metal contaminated sediments exposed to long-term hypoxia released Mn and Fe pulses. ► As flux increased under anoxic conditions Cd, Cu and Zn fluxes occurred only during the first week of hypoxia. ► Flux of these metals from 3 sites was not related to total sediment metal

A unique metal-semiconductor interface and resultant electron transfer phenomenon

OpenAIRE

Taft, S. L.

2012-01-01

An unusual electron transfer phenomenon has been identified from an n-type semiconductor to Schottky metal particles, the result of a unique metal semiconductor interface that results when the metal particles are grown from the semiconductor substrate. The unique interface acts as a one-way (rectifying) open gateway and was first identified in reduced rutile polycrystalline titanium dioxide (an n-type semiconductor) to Group VIII (noble) metal particles. The interface significantly affects th...

Time series models for prediction the total and dissolved heavy metals concentration in road runoff and soil solution of roadside embankments

Science.gov (United States)

Aljoumani, Basem; Kluge, Björn; sanchez, Josep; Wessolek, Gerd

2017-04-01

Highways and main roads are potential sources of contamination for the surrounding environment. High traffic rates result in elevated heavy metal concentrations in road runoff, soil and water seepage, which has attracted much attention in the recent past. Prediction of heavy metals transfer near the roadside into deeper soil layers are very important to prevent the groundwater pollution. This study was carried out on data of a number of lysimeters which were installed along the A115 highway (Germany) with a mean daily traffic of 90.000 vehicles per day. Three polyethylene (PE) lysimeters were installed at the A115 highway. They have the following dimensions: length 150 cm, width 100 cm, height 60 cm. The lysimeters were filled with different soil materials, which were recently used for embankment construction in Germany. With the obtained data, we will develop a time series analysis model to predict total and dissolved metal concentration in road runoff and in soil solution of the roadside embankments. The time series consisted of monthly measurements of heavy metals and was transformed to a stationary situation. Subsequently, the transformed data will be used to conduct analyses in the time domain in order to obtain the parameters of a seasonal autoregressive integrated moving average (ARIMA) model. Four phase approaches for identifying and fitting ARIMA models will be used: identification, parameter estimation, diagnostic checking, and forecasting. An automatic selection criterion, such as the Akaike information criterion, will use to enhance this flexible approach to model building

Insights into aquatic toxicities of the antibiotics oxytetracycline and ciprofloxacin in the presence of metal: Complexation versus mixture

Energy Technology Data Exchange (ETDEWEB)

Yu, Zhang [Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education), School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024 (China); Cai Xiyun, E-mail: xiyuncai@dlut.edu.cn [Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education), School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024 (China); Xianming, Lang [Liaoning Academy of Environmental Sciences, Shenyang 110031 (China); Xianliang, Qiao; Xuehua, Li; Jingwen, Chen [Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education), School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024 (China)

2012-07-15

Co-contamination of ligand-like antibiotics (e.g., tetracyclines and quinolones) and heavy metals prevails in the environment, and thus the complexation between them is involved in environmental risks of antibiotics. To understand toxicological significance of the complex, effects of metal coordination on antibiotics' toxicity were investigated. The complexation of two antibiotics, oxytetracycline and ciprofloxacin, with three heavy metals, copper, zinc, and cadmium, was verified by spectroscopic techniques. The antibiotics bound metals via multiple coordination sites and rendered a mixture of various complexation speciations. Toxicity analysis indicated that metal coordination did modify the toxicity of the antibiotics and that antibiotic, metal, and their complex acted primarily as concentration addition. Comparison of EC{sub 50} values revealed that the complex commonly was highest toxic and predominately correlated in toxicity to the mixture. Finally, environmental scenario analysis demonstrated that ignoring complexation would improperly classify environmental risks of the antibiotics. - Highlights: Black-Right-Pointing-Pointer The complex of antibiotic with metal is a mixture of various complexation modes. Black-Right-Pointing-Pointer Antibiotic and metal act as various combined interactions when their complexation is ignored. Black-Right-Pointing-Pointer Antibiotic, metal, and their complex act as concentration addition interaction. Black-Right-Pointing-Pointer Complex commonly is the highest toxicant. Black-Right-Pointing-Pointer Neglecting complexation renders improper classification of risks for antibiotics. - Antibiotic, heavy metal and their complex act primarily as concentration addition interaction and the complex commonly is highest toxic.

Oral bioaccessibility of toxic metals in contaminated oysters and relationships with metal internal sequestration.

Science.gov (United States)

Gao, Shi; Wang, Wen-Xiong

2014-12-01

The Hong Kong oysters Crassostrea hongkongensis are widely farmed in the estuarine waters of Southern China, but they accumulate Cu and Zn to alarmingly high concentrations in the soft tissues. Health risks of seafood consumption are related to contaminants such as toxic metals which are bioaccessible to humans. In the present study, we investigated the oral bioaccessibility of five toxic metals (Ag, Pb, Cd, Cu and Zn) in contaminated oysters collected from different locations of a large estuary in southern China. In all oysters, total Zn concentration was the highest whereas total Pb concentration was the lowest. Among the five metals, Ag had the lowest oral bioaccessibility (38.9-60.8%), whereas Cu and Zn had the highest bioaccessibility (72.3-93.1%). Significant negative correlation was observed between metal bioaccessibility and metal concentration in the oysters for Ag, Cd, and Cu. We found that the oral bioaccessibility of the five metals was positively correlated with their trophically available metal fraction (TAM) in the oyster tissues, and negatively correlated with metal distribution in the cellular debris. Thus, metal partitioning in the TAM and cellular debris controlled the oral bioaccessibility to humans. Given the dependence of oral bioaccessibility on tissue metal contamination, bioaccessibility needs to be incorporated in the risk assessments of contaminated shellfish. Copyright © 2014 Elsevier Inc. All rights reserved.

The final status of a metal surface after multipulse laser irradiation in an ambient gas

International Nuclear Information System (INIS)

Boulmer Leborgne, C.; Hermann, J.; Dubreuil, B.

1993-11-01

We have investigated the role of the ambient gas nature and pressure, and the influence of the laser pulse total duration and temporal shape in the coupling of the incident laser light of λ = 10.6μm wavelength to a metallic surface at intermediate laser intensities of 10 7 - 10 8 W/cm 2 . A plasma is accompanying then the action of the laser pulse. It is acting as an active moderator among laser beam and target thus determining the final status of the contact surface. (author). 11 refs, 6 figs

Long-term observation of water-soluble chemical components and acid-digested metals in the total suspended particles collected at Okinawa, Japan

Science.gov (United States)

Handa, D.; Okada, K.; Kuroki, Y.; Nakama, Y.; Nakajima, H.; Somada, Y.; Ijyu, M.; Azechi, S.; Oshiro, Y.; Nakaema, F.; Miyagi, Y.; Arakaki, T.; Tanahara, A.

2011-12-01

The economic growth and population increase in recent Asia have been increasing air pollution. Emission rate of air pollutants from Asia, in particular oxides of nitrogen, surpassed those from North America and Europe and should continue to exceed them for decades. Okinawa Island is situated approximately 1500 km south of Tokyo, Japan, 2000 km southeast of Beijing, China, and 1000 km south of South Korea. Its location is ideal in observing East Asia's air quality because maritime air mass prevails during summer, while continental air mass dominates during fall, winter, and spring. The maritime air mass data can be seen as background clean air and can be compared with continental air masses which have been affected by anthropogenic activities. We collected total suspended particles (TSP) on quartz filters by using a high volume air sampler at the Cape Hedo Atmosphere and Aerosol Monitoring Station (CHAAMS), Okinawa, Japan during August 2005 and August 2010. Sampling duration was one week for each sample. We determined the concentrations of water-soluble anions, cations, water-soluble organic carbon (WSOC) and acid-digested metals in TSP samples using ion chromatography, atomic absorption spectrometry, total organic carbon analyzer and Inductively Coupled Plasma Mass spectrometry (ICP-MS), respectively. Seasonal variation of water-soluble chemical components and acid-digested metals showed that the concentrations were the lowest in summer, higher in fall and winter, and the highest in spring. When air mass came from Asian continent, the concentrations of water-soluble chemical components and acid-digested metals were much higher compared to the other directions, suggesting long-range transport of air pollutants from Asian continent. Also, when the air mass came from Asian continent (75-100% dominant), the mean concentrations of non-sea salt sulfate and nitrate increased ca. 1.8 times and ca. 3.7 times, respectively between 2005 and 2010, and the ratio of nitrate to

Half-Metallic Ferromagnetism and Stability of Transition Metal Pnictides and Chalcogenides

Science.gov (United States)

Liu, Bang-Gui

It is highly desirable to explore robust half-metallic ferromagnetic materials compatible with important semiconductors for spintronic applications. A state-of-the-art full potential augmented plane wave method within the densityfunctional theory is reliable enough for this purpose. In this chapter we review theoretical research on half-metallic ferromagnetism and structural stability of transition metal pnictides and chalcogenides. We show that some zincblende transition metal pnictides are half-metallic and the half-metallic gap can be fairly wide, which is consistent with experiment. Systematic calculations reveal that zincblende phases of CrTe, CrSe, and VTe are excellent half-metallic ferromagnets. These three materials have wide half-metallic gaps, are low in total energy with respect to the corresponding ground-state phases, and, importantly, are structurally stable. Halfmetallic ferromagnetism is also found in wurtzite transition metal pnictides and chalcogenides and in transition-metal doped semiconductors as well as deformed structures. Some of these half-metallic materials could be grown epitaxially in the form of ultrathin .lms or layers suitable for real spintronic applications.

The Pseudomonas community in metal-contaminated sediments as revealed by quantitative PCR: a link with metal bioavailability.

Science.gov (United States)

Roosa, Stéphanie; Wauven, Corinne Vander; Billon, Gabriel; Matthijs, Sandra; Wattiez, Ruddy; Gillan, David C

2014-10-01

Pseudomonas bacteria are ubiquitous Gram-negative and aerobic microorganisms that are known to harbor metal resistance mechanisms such as efflux pumps and intracellular redox enzymes. Specific Pseudomonas bacteria have been quantified in some metal-contaminated environments, but the entire Pseudomonas population has been poorly investigated under these conditions, and the link with metal bioavailability was not previously examined. In the present study, quantitative PCR and cell cultivation were used to monitor and characterize the Pseudomonas population at 4 different sediment sites contaminated with various levels of metals. At the same time, total metals and metal bioavailability (as estimated using an HCl 1 m extraction) were measured. It was found that the total level of Pseudomonas, as determined by qPCR using two different genes (oprI and the 16S rRNA gene), was positively and significantly correlated with total and HCl-extractable Cu, Co, Ni, Pb and Zn, with high correlation coefficients (>0.8). Metal-contaminated sediments featured isolates of the Pseudomonas putida, Pseudomonas fluorescens, Pseudomonas lutea and Pseudomonas aeruginosa groups, with other bacterial genera such as Mycobacterium, Klebsiella and Methylobacterium. It is concluded that Pseudomonas bacteria do proliferate in metal-contaminated sediments, but are still part of a complex community. Copyright © 2014 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved.

Ionic Liquids as Extraction Media for Metal Ions

Science.gov (United States)

Hirayama, Naoki

In solvent extraction separation of metal ions, recently, many researchers have investigated possible use of hydrophobic ionic liquids as extraction media instead of organic solvents. Ionic liquids are salts of liquid state around room temperature and can act not only as solvents but also as ion-exchangers. Therefore, the extraction mechanism of metal ions into ionic liquids is complicated. This review presents current overview and perspective on evaluation of nature of hydrophobic ionic liquids as extraction media for metal ions.

Wear debris. An environmental issue in total joint replacement.

Science.gov (United States)

Manley, M T; Serekian, P

1994-01-01

There is a growing concern that osteolytic lesions, often adjacent to otherwise stable implants, are a recent phenomenon caused by some recent change in polyethylene, metal, or other aspect of the total hip construction. This study investigates the possibility that bearings and modular connections used in modern hip replacements are an unappreciated source of particulate debris. Measurements taken from contemporary femoral bearings show a significant mismatch in both surface finish and sphericity of mating metal and polyethylene components, with sphericity of inserts being much worse then sphericity of femoral heads. The tolerances for sphericity of polyethylene inserts were further changed by the placement of an insert into its metal shell. Hip simulator tests of assembled inserts and shells showed greater polyethylene weight loss for metal-backed shells than for inserts alone. Bending and torsional tests of metal/metal modular connections showed that dynamic loads can release large numbers of debris particles from taper junctions. Because osteolytic lesions clearly are associated with overload of tissue by debris particles, the design, manufacture, and tolerances of modular connections in total hip replacement all seem to require reevaluation.

Determination of total Betta-activity and heavy metals in biomonitor species (phytomonitors) from the area of ITR-Sofia

International Nuclear Information System (INIS)

Dimitrov, S.; Yovchev, M.; Geleva, E.

2010-01-01

For the purposes of environmental assessment of the area around the Research reactor in Sofia, species from monitored control points, selected in a certain way (habitat, population, air and hydrogeological parameters) are examined. Samples from following phytomonitored species: Betula pendula (silver birch) popullus canadensis (Canadian populus), Quercus sp. (Oak), Dactilus glomerata (Cock's-foot), Abies alba (Silver Fir) and Sequoia sempervirens (Coast Redwood) were analyzed. The total beta activity was determined by radiometric analysis and heavy metals content was measured using X-ray fluorescence analysis. The results are discussed in terms of radiation monitoring program of INRNE (gamma-background, aerosols, surface and groundwater, soil, plants) and obtained values are compared with reference points in the country

Light-induced attractive force between two metal bodies separated by a subwavelength slit

International Nuclear Information System (INIS)

Nesterov, Vladimir; Frumin, Leonid

2011-01-01

A novel light-induced attractive force which acts as a force with negative light pressure has been revealed. The force arises by the interaction of plasmon polaritons which are excited at the surface of metal when a transverse magnetic mode propagates through a subwavelength slit between two metal bodies. The estimation of the repulsive force acting on the metal walls of the slit in the case of subwavelength TE mode propagation along the slit is presented. The explicit analytical expressions of light-induced forces between two macroscopic metal bodies or films separated by a subwavelength slit have been derived. These forces could be used to manipulate metallic macro-, micro- and nano-objects in vacuum or in a dielectric medium. Estimations of these light-induced forces show that the forces are sufficient for measurements and practical applications

Macro and micro plastics sorb and desorb metals and act as a point source of trace metals to coastal ecosystems.

Science.gov (United States)

Munier, B; Bendell, L I

2018-01-01

Nine urban intertidal regions in Burrard Inlet, Vancouver, British Columbia, Canada, were sampled for plastic debris. Debris included macro and micro plastics and originated from a wide diversity of uses ranging from personal hygiene to solar cells. Debris was characterized for its polymer through standard physiochemical characteristics, then subject to a weak acid extraction to remove the metals, zinc, copper, cadmium and lead from the polymer. Recently manufactured low density polyethylene (LDPE), nylon, polyethylene terephthalate (PET), polypropylene (PP), polystyrene (PS) and polyvinyl chloride (PVC) were subject to the same extraction. Data was statistically analyzed by appropriate parametric and non-parametric tests when needed with significance set at P Plastic debris will affect metals within coastal ecosystems by; 1) providing a sorption site (copper and lead), notably for PVC 2) desorption from the plastic i.e., the "inherent" load (cadmium and zinc) and 3) serving as a point source of acute trace metal exposure to coastal ecosystems. All three mechanisms will put coastal ecosystems at risk to the toxic effects of these metals.

Observation of metallic sphere–complex plasma interactions in microgravity

International Nuclear Information System (INIS)

Schwabe, M; Zhdanov, S; Hagl, T; Huber, P; Rubin-Zuzic, M; Zaehringer, E; Thomas, H M; Lipaev, A M; Molotkov, V I; Naumkin, V N; Fortov, V E; Vinogradov, P V

2017-01-01

The PK-3 Plus laboratory on board the International Space Station is used to study the interaction between metallic spheres and a complex plasma. We show that the metallic spheres significantly affect both the local plasma environment and the microparticle dynamics. The spheres charge under the influence of the plasma and repel the microparticles, forming cavities surrounding the spheres. The size of the cavity around a sphere is used to study the force balance acting on microparticles at the cavity edge. We show that the ion drag force and pressure force from other microparticles balances with the electric force acting from the sphere to within 20%. At intermediate distances from the sphere surface, the interaction between the microparticles and the metallic spheres is attractive due to the drag force stemming from the ions which are moving towards the highly charged spheres. The spheres thus strongly affect the plasma fluxes. This modification of the plasma flux can lead to an effective surface tension acting on the microparticles, and to the excitation of dust-density waves near the spheres, as the local electric field crosses a threshold. (paper)

Heavy metal movement in metal-contaminated soil profiles

Energy Technology Data Exchange (ETDEWEB)

Li, Zhenbin; Shuman, L.M. [Univ. of Georgia, Griffin, GA (United States)

1996-10-01

Heavy metal movement in soil profiles is a major environmental concern because even slow transport through the soil may eventually lead to deterioration of groundwater quality. In this study, three metal-contaminated soil (Fuquay, Dothan, and Clarendon) were selected from cropland were a high-metal flue dust had been applied annually for 6 years to raise soil pH, with application ending 4 years before sampling. One uncontaminated soil (Tifton) from the same physiographic area was also sampled as a control. Soil samples were collected in 15-cm increments from the surface to 105 cm in depth. Total contents of Zn, Cd, and Pb in the soils samples were determined. To better understand metal movement in relation to metal fractions in the soil profile, soil samples were also extracted sequentially for exchangeable (EXC), organic matter (OM), Mn oxide (MNO), amorphous Fe oxide (AFEO), crystalline Fe oxide (CFEO), and residual (RES) fractions. 35 refs., 6 figs., 2 tabs.

The flow field acting on the fluttering profile, kinematics, forces and total moment

Czech Academy of Sciences Publication Activity Database

Kozánek, Jan; Vlček, Václav; Zolotarev, Igor

2013-01-01

Roč. 13, č. 7 (2013), s. 1-7 ISSN 0219-4554 R&D Projects: GA ČR GA101/09/1522 Institutional support: RVO:61388998 Keywords : fluttering profile * interferometry visualization * acting forces and moment Subject RIV: JU - Aeronautics, Aerodynamics, Aircrafts Impact factor: 1.059, year: 2013

Detection and quantitative determination of heavy metals in electronic cigarette refill liquids using Total Reflection X-ray Fluorescence Spectrometry.

Science.gov (United States)

Kamilari, Eleni; Farsalinos, Konstantinos; Poulas, Konstantinos; Kontoyannis, Christos G; Orkoula, Malvina G

2018-06-01

Electronic cigarettes are considered healthier alternatives to conventional cigarettes containing tobacco. They produce vapor through heating of the refill liquids (e-liquids) which consist of propylene glycol, vegetable glycerin, nicotine (in various concentrations), water and flavoring agents. Heavy metals may enter the refill liquid during the production, posing a risk for consumer's health due to their toxicity. The objective of the present study was the development of a methodology for the detection and quantitative analysis of cadmium (Cd), lead (Pb), nickel (Ni), copper (Cu), arsenic (As) and chromium (Cr), employing Total Reflection X-Ray Fluorescence Spectroscopy (TXRF) as an alternative technique to ICP-MS or ICP-OES commonly used for this type of analysis. TXRF was chosen due to its advantages, which include short analysis time, promptness, simultaneous multi-element analysis capability and minimum sample preparation, low purchase and operational cost. The proposed methodology was applied to a large number of electronic cigarette liquids commercially available, as well as their constituents, in order to evaluate their safety. TXRF may be a valuable tool for probing heavy metals in electronic cigarette refill liquids to serve for the protection of human health. Copyright © 2018 Elsevier Ltd. All rights reserved.

Edge loading has a paradoxical effect on wear in metal-on-polyethylene total hip arthroplasties.

Science.gov (United States)

Harris, William H

2012-11-01

Edge wear is an adverse factor that can negatively impact certain THAs. In some metal-on-metal THAs, it can lead to adverse tissue reactions including aseptic lymphocytic vasculitis-associated lesions and even to pseudotumor formation. In some ceramic-on-ceramic THAs, it can lead to squeaking and/or stripe wear. Edge wear in metal-on-metal and ceramic-on-ceramic THAs can also be associated with accelerated wear across the articulation of these joints. I asked: Does edge wear occur in metal-on-polyethylene (MOP) articulations? And if so, does it increase joint wear? I examined the evidence in the literature for edge wear occurring in MOP THA and then assessed the evidence in the literature for data supporting the concept that edge wear in MOP hips could accelerate wear across the articulation over time. Extensive data in the literature confirm edge wear is common in MOP THA. Surprisingly, the evidence does not support that it accelerates wear across the articulation. In fact, substantial data support the concept that it does not. These observations suggest, in terms of edge wear accelerating overall wear, MOP articulation may have a privileged position compared to hard-on-hard THA articulations.

Metal-on-metal hip joint tribology.

Science.gov (United States)

Dowson, D; Jin, Z M

2006-02-01

The basic tribological features of metal-on-metal total hip replacements have been reviewed to facilitate an understanding of the engineering science underpinning the renaissance of these hard-on-hard joints. Metal-on-polymer hip replacements operate in the boundary lubrication regime, thus leading to the design guidance to reduce the femoral head diameter as much as is feasible to minimize frictional torque and volumetric wear. This explains why the gold-standard implant of this form from the past half-century had a diameter of only 22.225 mm (7/8 in). Metal-on-metal implants can operate in the mild mixed lubrication regime in which much of the applied load is supported by elastohydrodynamic films. Correct tribological design leads to remarkably low steady state wear rates. Promotion of the most effective elastohydrodynamic films calls for the largest possible head diameters and the smallest clearances that can reasonably be adopted, consistent with fine surface finishes, good sphericity and minimal structural elastic deformation of the cup on its foundations. This guidance, which is opposite in form to that developed for metal-on-polymer joints, is equally valid for solid (monolithic) metallic heads on metallic femoral stems and surface replacement femoral shells. Laboratory measurements of friction and wear in metal-on-metal joints have confirmed their potential to achieve a very mild form of mixed lubrication. The key lies in the generation of effective elastohydrodynamic lubricating films of adequate thickness compared with the composite roughness of the head and cup. The calculation of the film thickness is by no means easy, but the full procedure is outlined and the use of an empirical formula that displays good agreement with calculations based upon the full numerical solutions is explained. The representation of the lambda ratio, lambda, embracing both film thickness and composite roughness, is described.

ACTS – SUCCESS STORY

Indian Academy of Sciences (India)

First page Back Continue Last page Overview Graphics. ACTS – SUCCESS STORY. Totally 103 experiments were conducted and the programme succeeded in the areas. Medicine; Education; Defence; Emergency Response; Maritime and Aeronautical Mobile Communications; Science and Astronomy.

Phytotoxicity of trace metals in spiked and field-contaminated soils: Linking soil-extractable metals with toxicity.

Science.gov (United States)

Hamels, Fanny; Malevé, Jasmina; Sonnet, Philippe; Kleja, Dan Berggren; Smolders, Erik

2014-11-01

Soil tests have been widely developed to predict trace metal uptake by plants. The prediction of metal toxicity, however, has rarely been tested. The present study was set up to compare 8 established soil tests for diagnosing phytotoxicity in contaminated soils. Nine soils contaminated with Zn or Cu by metal mining, smelting, or processing were collected. Uncontaminated reference soils with similar soil properties were sampled, and series of increasing contamination were created by mixing each with the corresponding soil. In addition, each reference soil was spiked with either ZnCl2 or CuCl2 at several concentrations. Total metal toxicity to barley seedling growth in the field-contaminated soils was up to 30 times lower than that in corresponding spiked soils. Total metal (aqua regia-soluble) toxicity thresholds of 50% effective concentrations (EC50) varied by factors up to 260 (Zn) or 6 (Cu) among soils. For Zn, variations in EC50 thresholds decreased as aqua regia > 0.43 M HNO3  > 0.05 M ethylenediamine tetraacetic acid (EDTA) > 1 M NH4 NO3  > cobaltihexamine > diffusive gradients in thin films (DGT) > 0.001 M CaCl2 , suggesting that the last extraction is the most robust phytotoxicity index for Zn. The EDTA extraction was the most robust for Cu-contaminated soils. The isotopically exchangeable fraction of the total soil metal in the field-contaminated soils markedly explained the lower toxicity compared with spiked soils. The isotope exchange method can be used to translate soil metal limits derived from soils spiked with metal salts to site-specific soil metal limits. © 2014 SETAC.

Nanodiamonds act as Trojan horse for intracellular delivery of metal ions to trigger cytotoxicity.

Science.gov (United States)

Zhu, Ying; Zhang, Yu; Shi, Guosheng; Yang, Jinrong; Zhang, Jichao; Li, Wenxin; Li, Aiguo; Tai, Renzhong; Fang, Haiping; Fan, Chunhai; Huang, Qing

2015-02-05

Nanomaterials hold great promise for applications in the delivery of various molecules with poor cell penetration, yet its potential for delivery of metal ions is rarely considered. Particularly, there is limited insight about the cytotoxicity triggered by nanoparticle-ion interactions. Oxidative stress is one of the major toxicological mechanisms for nanomaterials, and we propose that it may also contribute to nanoparticle-ion complexes induced cytotoxicity. To explore the potential of nanodiamonds (NDs) as vehicles for metal ion delivery, we used a broad range of experimental techniques that aimed at getting a comprehensive assessment of cell responses after exposure of NDs, metal ions, or ND-ion mixture: 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, Trypan blue exclusion text, optical microscope observation, synchrotron-based scanning transmission X-ray microscopy (STXM) and micro X-ray fluorescence (μXRF) microscopy, inductively coupled plasma-mass spectrometry (ICP-MS), reactive oxygen species (ROS) assay and transmission electron microscopy (TEM) observation. In addition, theoretical calculation and molecular dynamics (MD) computation were used to illustrate the adsorption properties of different metal ion on NDs as well as release profile of ion from ND-ion complexes at different pH values. The adsorption capacity of NDs for different metal ions was different, and the adsorption for Cu2+ was the most strong among divalent metal ions. These different ND-ion complexes then had different cytotoxicity by influencing the subsequent cellular responses. Detailed investigation of ND-Cu2+ interaction showed that the amount of released Cu2+ from ND-Cu2+ complexes at acidic lysosomal conditions was much higher than that at neutral conditions, leading to the elevation of intracellular ROS level, which triggered cytotoxicity. By theoretical approaches, we demonstrated that the functional carbon surface and cluster structures of NDs made them

Metal uptake and acute toxicity in zebrafish: Common mechanisms across multiple metals

Energy Technology Data Exchange (ETDEWEB)

Alsop, Derek, E-mail: alsopde@mcmaster.ca [Department of Biology, McMaster University, 1280 Main St. W., Hamilton, ON L8S 4K1 (Canada); Wood, Chris M. [Department of Biology, McMaster University, 1280 Main St. W., Hamilton, ON L8S 4K1 (Canada)

2011-10-15

All metals tested reduced calcium uptake in zebrafish larvae. However, it was whole body sodium loss that was functionally related to toxicity. The zebrafish larvae acute toxicity assay save time, space and resources. - Abstract: Zebrafish larvae (Danio rerio) were used to examine the mechanisms of action and acute toxicities of metals. Larvae had similar physiological responses and sensitivities to waterborne metals as adults. While cadmium and zinc have previously been shown to reduce Ca{sup 2+} uptake, copper and nickel also decreased Ca{sup 2+} uptake, suggesting that the epithelial transport of all these metals is through Ca{sup 2+} pathways. However, exposure to cadmium, copper or nickel for up to 48 h had little or no effect on total whole body Ca{sup 2+} levels, indicating that the reduction of Ca{sup 2+} uptake is not the acute toxic mechanism of these metals. Instead, mortalities were effectively related to whole body Na{sup +}, which decreased up to 39% after 48 h exposures to different metals around their respective 96 h LC50s. Decreases in whole body K{sup +} were also observed, although they were not as pronounced or frequent as Na{sup +} losses. None of the metals tested inhibited Na{sup +} uptake in zebrafish (Na{sup +} uptake was in fact increased with exposure) and the observed losses of Na{sup +}, K{sup +}, Ca{sup 2+} and Mg{sup 2+} were proportional to the ionic gradients between the plasma and water, indicating diffusive ion loss with metal exposure. This study has shown that there is a common pathway for metal uptake and a common mechanism of acute toxicity across groups of metals in zebrafish. The disruption of ion uptake accompanying metal exposure does not appear to be responsible for the acute toxicity of metals, as has been previously suggested, but rather the toxicity is instead due to total ion loss (predominantly Na{sup +}).

The Assessment of Sediment Heavy Metal Pollution in Begej Canal (Serbia)

Science.gov (United States)

Krčmar, Dejan; Trickovic, Jelena; Grba, Nenad; Becelic Tomin, Milena; Pesic, Vesna; Varga, Natasa; Dalmacija, Bozo

2016-04-01

Accumulation of heavy metals in aquatic systems has received huge concern due to their toxicity, persistence and subsequent accumulation in aquatic sediments. One of the most crucial properties of the metals, which differentiate them from organic pollutants, is that they are not biodegradable in the environment. Metals are part of biogeochemical cycles with aquatic sediments acting as their ultimate sinks for longer periods of time. However, when environmental conditions change (pH, redox potential, etc.) sediments act as secondary sources of metal pollution. The toxicity and mobility of metals depend strongly on the way they are associated with sediments. Therefore, information on the total concentrations of metals in sediment alone should not be used to assess the environmental impact of polluted sediments. The Begej Canal is navigation canal between Romania and Serbia and it is a part of Danube-Tisa-Danube hydrosystem in Vojvodina (Northern Province of Serbia). Approximately, 500,000 m3 of sediment is accumulated in Begej canal which currently prevents canal's primary function - navigability. The objective of the present study was to assess the chemical quality of Begej canal sediments regarding heavy metals content. The concentrations of heavy metals were as follows: Cd - 2.4-4.9 mg/kg, Cr - 125-349 mg/kg, Cu - 65-124 mg/kg, Pb - 47-113 mg/kg, Ni - 45-88 mg/kg and Zn - 362-602 mg/kg. According to Serbian legislation (Official gazette, no. 50/12), sediment of Begej canal is the third class sediment which means that special measures should be taken in case of its removal from watercourse and final disposal in order to prevent contamination of other environmental compartments (soil, ground waters, surface waters, wildlife). Therefore, determination of third class has important economic and social implications. Additional tests to assess sediment quality included determination of contamination factor (CF), pollution load index (PLI) and enrichment factor (EF). In

Metallic attenuated total reflection infrared hollow fibers for robust optical transmission systems

Energy Technology Data Exchange (ETDEWEB)

Jing, Chengbin; Guo, Hong; Hu, Zhigao; Yang, Pingxiong [Key Laboratory of Polar Materials and Devices, Ministry of Education, Department of Electronic Engineering, East China Normal University, 500 Dongchuan Road, Shanghai 200241 (China); Chu, Junhao [Key Laboratory of Polar Materials and Devices, Ministry of Education, Department of Electronic Engineering, East China Normal University, 500 Dongchuan Road, Shanghai 200241 (China); National Laboratory for Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Sciences, 500 Yu-tian Road, Shanghai 200083 (China); Liu, Aiyun [Department of Physics, Shanghai Normal University, 100 Gui Lin Road, Shanghai 200234 (China); Shi, Yiwei [School of Information Science and Engineering, Fudan University, 220 Handan Road, Shanghai 200433 (China)

2014-07-07

A durable metallic attenuated total reflection (ATR) hollow fiber (bore size: 1.45 mm, wall thickness: 50 μm) was designed and fabricated based on a nickel capillary tube and hexagonal germanium dioxide (GeO{sub 2}). The anomalous dispersion of the hexagonal GeO{sub 2} layer grown inside a nickel tube achieves low-loss light transmission at two peak-power wavelengths for CO{sub 2} laser devices (10.2 and 10.6 μm). An 11–28 W, 10.2 or 10.6 μm CO{sub 2} laser power was steadily delivered via a fiber elastically bent from 0° to 90° (radius: 45 cm) for over 40 min (transmission loss: 0.22 to 4.2 dB/m). Theoretically fitting the measured temperatures showed that front-end clipping caused greater thermal loading than the distributed mode absorption. The maximum external temperature of a nickel ATR fiber is much lower than that of a silica glass ATR fiber owing to their different heat dissipation abilities. The HE{sub 11} mode purity of the output beam profiles decreased from 90.3% to 44.7% as the bending angle increased from 0° to 90°. Large core sizes and wall roughnesses (scattering loss 0.04 dB/m) contributed to mode mixing and excess losses that were above the value predicted by the classical Marcatili and Schmeltzer equation (0.024–0.037 dB/m).

Tribo-biological deposits on the articulating surfaces of metal-on-polyethylene total hip implants retrieved from patients

Science.gov (United States)

Cui, Zhiwei; Tian, Yi-Xing; Yue, Wen; Yang, Lei; Li, Qunyang

2016-06-01

Artificial total hip arthroplasty (THA) is one of the most effective orthopaedic surgeries that has been used for decades. However, wear of the articulating surfaces is one of the key failure causes limiting the lifetime of total hip implant. In this paper, Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM) were employed to explore the composition and formation mechanism of the tribo-layer on the articulating surfaces of metal-on-polyethylene (MoPE) implants retrieved from patients. Results showed that, in contrast to conventional understanding, the attached tribo-layer contained not only denatured proteins but also a fraction of polymer particles. The formation of the tribo-layer was believed to relate to lubrication regime, which was supposed to be largely affected by the nature of the ultra-high-molecule-weight-polyethylene (UHMWPE). Wear and formation of tribo-layer could be minimized in elasto-hydrodynamic lubrication (EHL) regime when the UHMWPE was less stiff and have a morphology containing micro-pits; whereas the wear was more severe and tribo-layer formed in boundary lubrication. Our results and analyses suggest that enhancing interface lubrication may be more effective on reducing wear than increasing the hardness of material. This finding may shed light on the design strategy of artificial hip joints.

Short-term changes of metal availability in soil. Part I: Comparing sludge-amended with metal-spiked soils.

NARCIS (Netherlands)

Natal-da-Luz, T.; Ojeda, G.; Costa, D.M.; Pratas, J.; Lanno, R.P.; van Gestel, C.A.M.; Sousa, J.P.

2012-01-01

Sewage sludge application to soils is regulated by its total metal content. However, the real risk of metals is determined by the fraction that is biologically available. The available fraction is highly related to the strength of metal binding by the matrix, which is a dynamic process. The

Tribology of total hip arthroplasty prostheses

Science.gov (United States)

Rieker, Claude B.

2016-01-01

Articulating components should minimise the generation of wear particles in order to optimize long-term survival of the prosthesis. A good understanding of tribological properties helps the orthopaedic surgeon to choose the most suitable bearing for each individual patient. Conventional and highly cross-linked polyethylene articulating either with metal or ceramic, ceramic-on-ceramic and metal-on-metal are the most commonly used bearing combinations. All combinations of bearing surface have their advantages and disadvantages. An appraisal of the individual patient’s objectives should be part of the assessment of the best bearing surface. Cite this article: Rieker CB. Tribology of total hip arthroplasty prostheses: what an orthopaedic surgeon should know. EFORT Open Rev 2016;1:52-57. DOI: 10.1302/2058-5241.1.000004. PMID:28461928

Tracking environmental impacts in global product chains - Rare Earth Metals and other critical metals used in the cleantech industry

Energy Technology Data Exchange (ETDEWEB)

Pathan, A.; Schilli, A.; Johansson, J.; Vehvilaeinen, I.; Larsson, A.; Hutter, J.

2013-03-15

Metals form a central part of the global economy, but their extraction and supply are linked to several environmental and social concerns. This study aims to create a picture of the supply chain of Rare Earth Metals (REMs) and other critical metals used in the clean technology (cleantech) sectors of electric vehicles and solar panels. The study examines how Nordic cleantech companies are aware and acting on the challenges related to the lifecycle of these metals and what are the potentials to minimise environmental and social impacts. Recommendations of the study can be summarised as three initiatives: establishment of an awareness platform and roundtable initiative (short-term), research and information gathering (mid-term), and development of closed-loop solutions (long-term). (Author)

Macro and micro plastics sorb and desorb metals and act as a point source of trace metals to coastal ecosystems.

Directory of Open Access Journals (Sweden)

B Munier

Full Text Available Nine urban intertidal regions in Burrard Inlet, Vancouver, British Columbia, Canada, were sampled for plastic debris. Debris included macro and micro plastics and originated from a wide diversity of uses ranging from personal hygiene to solar cells. Debris was characterized for its polymer through standard physiochemical characteristics, then subject to a weak acid extraction to remove the metals, zinc, copper, cadmium and lead from the polymer. Recently manufactured low density polyethylene (LDPE, nylon, polyethylene terephthalate (PET, polypropylene (PP, polystyrene (PS and polyvinyl chloride (PVC were subject to the same extraction. Data was statistically analyzed by appropriate parametric and non-parametric tests when needed with significance set at P < 0.05. Polymers identified in field samples in order of abundance were; PVC (39, LDPE (28, PS (18, polyethylene (PE, 9, PP (8, nylon (8, high density polyethylene (HDPE, 7, polycarbonate (PC, 6, PET (6, polyurethane (PUR, 3 and polyoxymethylene (POM, 2. PVC and LDPE accounted for 46% of all samples. Field samples of PVC, HDPE and LDPE had significantly greater amounts of acid extracted copper and HDPE, LDPE and PUR significantly greater amounts of acid extracted zinc. PVC and LDPE had significantly greater amounts of acid extracted cadmium and PVC tended to have greater levels of acid extracted lead, significantly so for HDPE. Five of the collected items demonstrated extreme levels of acid extracted metal; greatest concentrations were 188, 6667, 698,000 and 930 μgg-1 of copper, zinc, lead and cadmium respectively recovered from an unidentified object comprised of PVC. Comparison of recently manufactured versus field samples indicated that recently manufactured samples had significantly greater amounts of acid extracted cadmium and zinc and field samples significantly greater amounts of acid extracted copper and lead which was primarily attributed to metal extracted from field samples of PVC

Chemodynamics of heavy metals in long-term contaminated soils: metal speciation in soil solution.

Science.gov (United States)

Kim, Kwon-Rae; Owens, Gary

2009-01-01

The concentration and speciation of heavy metals in soil solution isolated from long-term contaminated soils were investigated. The soil solution was extracted at 70% maximum water holding capacity (MWHC) after equilibration for 24 h. The free metal concentrations (Cd2+, CU2+, Pb2+, and Zn2+) in soil solution were determined using the Donnan membrane technique (DMT). Initially the DMT was validated using artificial solutions where the percentage of free metal ions were significantly correlated with the percentages predicted using MINTEQA2. However, there was a significant difference between the absolute free ion concentrations predicted by MINTEQA2 and the values determined by the DMT. This was due to the significant metal adsorption onto the cation exchange membrane used in the DMT with 20%, 28%, 44%, and 8% mass loss of the initial total concentration of Cd, Cu, Pb, and Zn in solution, respectively. This could result in a significant error in the determination of free metal ions when using DMT if no allowance for membrane cation adsorption was made. Relative to the total soluble metal concentrations the amounts of free Cd2+ (3%-52%) and Zn2+ (11%-72%) in soil solutions were generally higher than those of Cu2+ (0.2%-30%) and Pb2+ (0.6%-10%). Among the key soil solution properties, dissolved heavy metal concentrations were the most significant factor governing free metal ion concentrations. Soil solution pH showed only a weak relationship with free metal ion partitioning coefficients (K(p)) and dissolved organic carbon did not show any significant influence on K(p).

Metal ion concentrations in body fluids after implantation of hip replacements with metal-on-metal bearing--systematic review of clinical and epidemiological studies.

Directory of Open Access Journals (Sweden)

Albrecht Hartmann

Full Text Available INTRODUCTION: The use of metal-on-metal (MoM total hip arthroplasty (THA increased in the last decades. A release of metal products (i.e. particles, ions, metallo-organic compounds in these implants may cause local and/or systemic adverse reactions. Metal ion concentrations in body fluids are surrogate measures of metal exposure. OBJECTIVE: To systematically summarize and critically appraise published studies concerning metal ion concentrations after MoM THA. METHODS: Systematic review of clinical trials (RCTs and epidemiological studies with assessment of metal ion levels (cobalt, chromium, titanium, nickel, molybdenum in body fluids after implantation of metalliferous hip replacements. Systematic search in PubMed and Embase in January 2012 supplemented by hand search. Standardized abstraction of pre- and postoperative metal ion concentrations stratified by type of bearing (primary explanatory factor, patient characteristics as well as study quality characteristics (secondary explanatory factors. RESULTS: Overall, 104 studies (11 RCTs, 93 epidemiological studies totaling 9.957 patients with measurement of metal ions in body fluids were identified and analyzed. Consistently, median metal ion concentrations were persistently elevated after implantation of MoM-bearings in all investigated mediums (whole blood, serum, plasma, erythrocytes, urine irrespective of patient characteristics and study characteristics. In several studies very high serum cobalt concentrations above 50 µg/L were measured (detection limit typically 0.3 µg/L. Highest metal ion concentrations were observed after treatment with stemmed large-head MoM-implants and hip resurfacing arthroplasty. DISCUSSION: Due to the risk of local and systemic accumulation of metallic products after treatment with MoM-bearing, risk and benefits should be carefully balanced preoperatively. The authors support a proposed "time out" for stemmed large-head MoM-THA and recommend a restricted

Radioactive materials in recycled metals.

Science.gov (United States)

Lubenau, J O; Yusko, J G

1995-04-01

In recent years, the metal recycling industry has become increasingly aware of an unwanted component in metal scrap--radioactive material. Worldwide, there have been 35 instances where radioactive sources were unintentionally smelted in the course of recycling metal scrap. In some cases contaminated metal consumer products were distributed internationally. In at least one case, serious radiation exposures of workers and the public occurred. Radioactive material appearing in metal scrap includes sources subject to licensing under the Atomic Energy Act and also naturally occurring radioactive material. U.S. mills that have smelted a radioactive source face costs resulting from decontamination, waste disposal, and lost profits that range from 7 to 23 million U.S. dollars for each event. To solve the problem, industry and the government have jointly undertaken initiatives to increase awareness of the problem within the metal recycling industry. Radiation monitoring of recycled metal scrap is being performed increasingly by mills and, to a lesser extent, by scrap processors. The monitoring does not, however, provide 100% protection. Improvements in regulatory oversight by the government could stimulate improved accounting and control of licensed sources. However, additional government effort in this area must be reconciled with competing priorities in radiation safety and budgetary constraints. The threat of radioactive material in recycled metal scrap will continue for the foreseeable future and, thus, poses regulatory policy challenges for both developed and developing nations.

Diabetes and the Affordable Care Act.

Science.gov (United States)

Burge, Mark R; Schade, David S

2014-07-01

The Affordable Care Act--"Obamacare"--is the most important federal medical legislation to be enacted since Medicare. Although the goal of the Affordable Care Act is to improve healthcare coverage, access, and quality for all Americans, people with diabetes are especially poised to benefit from the comprehensive reforms included in the act. Signed into law in 2010, this massive legislation will slowly be enacted over the next 10 years. In the making for at least a decade, it will affect every person in the United States, either directly or indirectly. In this review, we discuss the major changes in healthcare that will take place in the next several years, including (1) who needs to purchase insurance on the Web-based exchange, (2) the cost to individuals and the rebates that they may expect, (3) the rules and regulations for purchasing insurance, (4) the characteristics of the different "metallic" insurance plans that are available, and (5) the states that have agreed to participate. With both tables and figures, we have tried to make the Affordable Care Act both understandable and appreciated. The goal of this comprehensive review is to highlight aspects of the Affordable Care Act that are of importance to practitioners who care for people with diabetes by discussing both the positive and the potentially negative aspects of the program as they relate to diabetes care.

Analysis of heavy metals and minerals elements in the turmeric using Total-Reflection X-ray Fluorescence analysis technique and Atomic Absorption Spectrometry

International Nuclear Information System (INIS)

Andriamisetra, V.M.Z.

2014-01-01

Currently, many studies demonstrate anti-cancer and anti-inflammatory benefits of turmeric. The aims of this work is to perform analysis of metals such as calcium, chromium, manganese, iron, cobalt, nickel, copper, zinc, arsenic, bromine, rubidium, strontium, cadmium and lead in the turmeric collected from various places in Madagascar. The analysis by total reflection X-ray fluorescence technique is used to determine the concentrations of heavy metals, while the atomic absorption spectrometry is used for the determination of trace elements. Analysis results show that the concentration of calcium in the turmeric is very high, its average concentration is 1025.8 mg.kg -1 . The average concentrations of manganese, of copper and of iron are respectively 44.7 mg.kg -1 ; 19.7 mg.kg -1 and 53.6 mg.kg -1 . The average concentrations of zinc, of rubidium and of strontium are respectively 17.3 mg.kg -1 ; 35.2 mg.kg -1 and 21.7 mg.kg -1 [fr

Plasmonic reflectors and high-Q nano-cavities based on coupled metal-insulator-metal waveguides

Directory of Open Access Journals (Sweden)

Jing Chen

2012-03-01

Full Text Available Based on the contra-directional coupling, a composite structure consisting of two coupled metal-insulator-metal (MIM waveguides is proposed to act as an attractive plasmonic reflector. By introducing a defect into one of the MIM waveguides, we show that such a composite structure can be operated as a plasmonic nanocavity with a high quality factor. Both symmetric and anti-symmetric cavity modes are supported in the plasmonic cavity, and their resonance frequencies can be tuned by controlling the defect width. The present structures could have a significant impact for potential applications such as surface plasmon mirrors, filters and solid-state cavity quantum electrodynamics.

Selective removal/recovery of RCRA metals from waste and process solutions using polymer filtration trademark technology

International Nuclear Information System (INIS)

Smith, B.F.

1997-01-01

Resource Conservation and Recovery Act (RCRA) metals are found in a number of process and waste streams at many DOE, U.S. Department of Defense, and industrial facilities. RCRA metals consist principally of chromium, mercury, cadmium, lead, and silver. Arsenic and selenium, which form oxyanions, are also considered RCRA elements. Discharge limits for each of these metals are based on toxicity and dictated by state and federal regulations (e.g., drinking water, RCRA, etc.). RCRA metals are used in many current operations, are generated in decontamination and decommissioning (D ampersand D) operations, and are also present in old process wastes that require treatment and stabilization. These metals can exist in solutions, as part of sludges, or as contaminants on soils or solid surfaces, as individual metals or as mixtures with other metals, mixtures with radioactive metals such as actinides (defined as mixed waste), or as mixtures with a variety of inert metals such as calcium and sodium. The authors have successfully completed a preliminary proof-of-principle evaluation of Polymer Filtration trademark (PF) technology for the dissolution of metallic mercury and have also shown that they can remove and concentrate RCRA metals from dilute solutions for a variety of aqueous solution types using PF technology. Another application successfully demonstrated is the dilute metal removal of americium and plutonium from process streams. This application was used to remove the total alpha contamination to below 30 pCi/L for the wastewater treatment plant at TA-50 at Los Alamos National Laboratory (LANL) and from nitric acid distillate in the acid recovery process at TA-55, the Plutonium Facility at LANL (ESP-CP TTP AL16C322). This project will develop and optimize the PF technology for specific DOE process streams containing RCRA metals and coordinate it with the needs of the commercial sector to ensure that technology transfer occurs

Selective removal/recovery of RCRA metals from waste and process solutions using polymer filtration{trademark} technology

Energy Technology Data Exchange (ETDEWEB)

Smith, B.F. [Los Alamos National Lab., NM (United States)

1997-10-01

Resource Conservation and Recovery Act (RCRA) metals are found in a number of process and waste streams at many DOE, U.S. Department of Defense, and industrial facilities. RCRA metals consist principally of chromium, mercury, cadmium, lead, and silver. Arsenic and selenium, which form oxyanions, are also considered RCRA elements. Discharge limits for each of these metals are based on toxicity and dictated by state and federal regulations (e.g., drinking water, RCRA, etc.). RCRA metals are used in many current operations, are generated in decontamination and decommissioning (D&D) operations, and are also present in old process wastes that require treatment and stabilization. These metals can exist in solutions, as part of sludges, or as contaminants on soils or solid surfaces, as individual metals or as mixtures with other metals, mixtures with radioactive metals such as actinides (defined as mixed waste), or as mixtures with a variety of inert metals such as calcium and sodium. The authors have successfully completed a preliminary proof-of-principle evaluation of Polymer Filtration{trademark} (PF) technology for the dissolution of metallic mercury and have also shown that they can remove and concentrate RCRA metals from dilute solutions for a variety of aqueous solution types using PF technology. Another application successfully demonstrated is the dilute metal removal of americium and plutonium from process streams. This application was used to remove the total alpha contamination to below 30 pCi/L for the wastewater treatment plant at TA-50 at Los Alamos National Laboratory (LANL) and from nitric acid distillate in the acid recovery process at TA-55, the Plutonium Facility at LANL (ESP-CP TTP AL16C322). This project will develop and optimize the PF technology for specific DOE process streams containing RCRA metals and coordinate it with the needs of the commercial sector to ensure that technology transfer occurs.

The Measurement of Hardness and Elastic Modulus of non-Metallic Inclusions in Steely Welding Joints

Directory of Open Access Journals (Sweden)

Ignatova Anna

2015-08-01

Full Text Available Trunk pipelines work under a cyclic dynamical mechanical load because when oil or gas is pumped, the pressure constantly changes - pulsates. Therefore, the fatigue phenomenon is a common reason of accidents. The fatigue phenomenon more often happens in the zone of non-metallic inclusions concentration. To know how the characteristics of nonmetallic inclusions influence the probability of an accident the most modern research methods should be used. It is determined with the help of the modern research methods that the accident rate of welded joints of pipelines is mostly influenced by their morphological type, composition and size of nonmetallic inclusions, this effect is more important than the common level of pollution by non-metallic inclusions. The article presents the results of the investigations of welded joints, obtained after the use of different common welding materials. We used the methods, described in the state standards: scanning electronic microscopy, spectral microprobe analysis and nano-indentation. We found out that non-metallic inclusions act like stress concentrators because they shrink, forming a blank space between metal and nonmetallic inclusions; it strengthens the differential properties on this boundary. Nonmetallic inclusion is not fixed, it can move. The data that we have received mean that during welded joints’ contamination (with non-metallic inclusions monitoring process, more attention should be paid to the content of definite inclusions, but not to total contamination.

Metal Ion Concentrations in Body Fluids after Implantation of Hip Replacements with Metal-on-Metal Bearing – Systematic Review of Clinical and Epidemiological Studies

Science.gov (United States)

Hartmann, Albrecht; Hannemann, Franziska; Lützner, Jörg; Seidler, Andreas; Drexler, Hans; Günther, Klaus-Peter; Schmitt, Jochen

2013-01-01

Introduction The use of metal-on-metal (MoM) total hip arthroplasty (THA) increased in the last decades. A release of metal products (i.e. particles, ions, metallo-organic compounds) in these implants may cause local and/or systemic adverse reactions. Metal ion concentrations in body fluids are surrogate measures of metal exposure. Objective To systematically summarize and critically appraise published studies concerning metal ion concentrations after MoM THA. Methods Systematic review of clinical trials (RCTs) and epidemiological studies with assessment of metal ion levels (cobalt, chromium, titanium, nickel, molybdenum) in body fluids after implantation of metalliferous hip replacements. Systematic search in PubMed and Embase in January 2012 supplemented by hand search. Standardized abstraction of pre- and postoperative metal ion concentrations stratified by type of bearing (primary explanatory factor), patient characteristics as well as study quality characteristics (secondary explanatory factors). Results Overall, 104 studies (11 RCTs, 93 epidemiological studies) totaling 9.957 patients with measurement of metal ions in body fluids were identified and analyzed. Consistently, median metal ion concentrations were persistently elevated after implantation of MoM-bearings in all investigated mediums (whole blood, serum, plasma, erythrocytes, urine) irrespective of patient characteristics and study characteristics. In several studies very high serum cobalt concentrations above 50 µg/L were measured (detection limit typically 0.3 µg/L). Highest metal ion concentrations were observed after treatment with stemmed large-head MoM-implants and hip resurfacing arthroplasty. Discussion Due to the risk of local and systemic accumulation of metallic products after treatment with MoM-bearing, risk and benefits should be carefully balanced preoperatively. The authors support a proposed „time out“ for stemmed large-head MoM-THA and recommend a restricted indication for hip

Decomposition of metal nitrate solutions

International Nuclear Information System (INIS)

Haas, P.A.; Stines, W.B.

1982-01-01

Oxides in powder form are obtained from aqueous solutions of one or more heavy metal nitrates (e.g. U, Pu, Th, Ce) by thermal decomposition at 300 to 800 deg C in the presence of about 50 to 500% molar concentration of ammonium nitrate to total metal. (author)

Compacted sewage sludge as a barrier for tailings: the heavy metal speciation and total organic carbon content in the compacted sludge specimen.

Directory of Open Access Journals (Sweden)

Huyuan Zhang

Full Text Available Acid mine drainage (AMD was the main environmental problem facing the mining industry. For AMD had high heavy metals content and low pH, the compacted sewage sludge might be a barrier for tailings whose oxidation and weathering produced AMD, with its own carbon source, microorganism reduction ability and impermeability. To study the heavy metals environmental risk, under the simulate AMD, the deionized water (DW, and the pH 2.1 sulfuric acid water (SA seepage conditions, respectively, the changes of the chemical speciation of heavy metals Cd, Cu, Fe, Ni, Zn and total organic carbon (TOC content in the compacted sewage sludge were assessed in the different periods. The results indicated according to the distribution of heavy metals, the potential mobility was for Cd: 6.08 under AMD, 7.48 under SA, ∞ under DW; for Cu: 0.08 under AMD, 0.17 under SA, 0.59 under DW; for Fe: 0.15 under AMD, 0.22 under SA, 0.22 under DW; for Ni: 2.60 under AMD, 1.69 under SA, 1.67 under DW; and for Zn: 0.15 under AMD, 0.23 under SA and 0.21 under DW at the second checking time. TOC content firstly decreased from 67.62±0% to 66.29±0.35%, then increased to 67.74±0.65% under the AMD seepage while TOC decreased to 63.30±0.53%, then to 61.33±0.37% under the DW seepage, decreased to 63.86±0.41%, then to 63.28±0.49% under SA seepage. That indicated under the AMD seepage, the suitable microorganisms communities in the compacted sewage sludge were activated. And the heavy metals environmental risk of compacted sewage sludge was lower with AMD condition than with other two. So the compacted sewage sludge as a barrier for tailings was feasible as the aspect of environmental risk assessment.

Patch testers' opinions regarding diagnostic criteria for metal hypersensitivity reactions to metallic implants.

Science.gov (United States)

Schalock, Peter C; Thyssen, Jacob P

2013-01-01

Metal hypersensitivity reactions to implanted devices remain a challenging and controversial topic. Diagnostic criteria and methods are not well delineated. Diagnostic criteria for hypersensitivity reactions after metallic device implantation are evaluated in this study by a multinational group of patch testers using Thyssen's previously published criteria. A total of 119 dermatologists at the 2012 European Contact Dermatitis Society and 2013 American Contact Dermatitis Society meetings answered a survey regarding their opinions on topics relating to metal hypersensitivity. Four major and 5 minor diagnostic criteria emerged. Approximately 80% of respondents found the following criteria useful (major criteria): chronic dermatitis beginning weeks to months after metallic implantation, eruption overlying the metal implant, positive patch test to a metal component of the implant, and complete clearing after removal of the potentially allergenic implant. Minor criteria (metals (eg, lymphocyte transformation test). In the challenging situation such as a symptomatic or failing orthopedic device, applying these 4 major criteria and the 5 supportive minor criteria may be useful for guiding decision making.

Microfluidic paper-based device for colorimetric determination of glucose based on a metal-organic framework acting as peroxidase mimetic.

Science.gov (United States)

Ortiz-Gómez, Inmaculada; Salinas-Castillo, Alfonso; García, Amalia García; Álvarez-Bermejo, José Antonio; de Orbe-Payá, Ignacio; Rodríguez-Diéguez, Antonio; Capitán-Vallvey, Luis Fermín

2017-12-13

This work presents a microfluidic paper-based analytical device (μPAD) for glucose determination using a supported metal-organic framework (MOF) acting as a peroxidase mimic. The catalytic action of glucose oxidase (GOx) on glucose causes the formation of H 2 O 2 , and the MOF causes the oxidation of 3,3',5,5'-tetramethylbenzidine (TMB) by H 2 O 2 to form a blue-green product with an absorption peak at 650 nm in the detection zone. A digital camera and the iOS feature of a smartphone are used for the quantitation of glucose with the S coordinate of the HSV color space as the analytical parameter. Different factors such as the concentration of TMB, GOx and MOF, pH and buffer, sample volume, reaction time and reagent position in the μPAD were optimized. Under optimal conditions, the value for the S coordinate increases linearly up to 150 μmol·L -1 glucose concentrations, with a 2.5 μmol·L -1 detection limit. The μPAD remains stable for 21 days under conventional storage conditions. Such an enzyme mimetic-based assay to glucose determination using Fe-MIL-101 MOF implemented in a microfluidic paper-based device possesses advantages over enzyme-based assays in terms of costs, durability and stability compared to other existing glucose determination methods. The procedure was applied to the determination of glucose in (spiked) serum and urine. Graphical abstract Schematic representation of microfluidic paper-based analytical device using metal-organic framework as a peroxidase mimic for colorimetric glucose detection with digital camera or smartphone and iOS app readout.

Heavy metal toxicity and iron chlorosis

Energy Technology Data Exchange (ETDEWEB)

DeKock, P C

1956-01-01

The toxicity of copper, nickel, cobalt, zinc, chromium, and manganese to mustard was studied in water culture, utilizing either the ionic form or the EDTA chelate of the metal in the presence of either ferric chloride or ferric EDTA. In presence of ferric chloride the activity of the metals in producing chlorosis was as given above, i.e. in the order of stability of their chelates. In the presence of ferric versenate, toxicity of the ionic metal was much reduced. The metal chelates gave very little indication of toxicity with either form of iron. It was found that the ratio of total phosphorus to total iron was higher in chlorotic plants than in green plants, irrespective of which metal was causing the toxicity. Copper could be demonstrated in the phloem cells of the root using biscyclohexanone-oxalydihydrazone as histochemical reagent. It is postulated that transport of iron probably takes place in the phloem as an active process. It would appear that as a major part of the iron in plant cells is attached to nucleo- or phospho-proteins, the heavy metals must be similarly attached to phospho-proteins.

Do constructed wetlands remove metals or increase metal bioavailability?

Science.gov (United States)

Xu, Xiaoyu; Mills, Gary L

2018-07-15

The H-02 wetland was constructed to treat building process water and storm runoff water from the Tritium Processing Facility on the Department of Energy's Savannah River Site (Aiken, SC). Monthly monitoring of copper (Cu) and zinc (Zn) concentrations and water quality parameters in surface waters continued from 2014 to 2016. Metal speciation was modeled at each sampling occasion. Total Cu and Zn concentrations released to the effluent stream were below the NPDES limit, and the average removal efficiency was 65.9% for Cu and 71.1% for Zn. The metal-removal processes were found out to be seasonally regulated by sulfur cycling indicated by laboratory and model results. High temperature, adequate labile organic matter, and anaerobic conditions during the warm months (February to August) favored sulfate reduction that produced sulfide minerals to significantly remove metals. However, the dominant reaction in sulfur cycling shifted to sulfide oxidation during the cool months (September to next March). High concentrations of metal-organic complexes were observed, especially colloidal complexes of metal and fulvic acid (FA), demonstrating adsorption to organic matter became the primary process for metal removal. Meanwhile, the accumulation of metal-FA complexes in the wetland system will cause negative effects to the surrounding environment as they are biologically reactive, highly bioavailable, and can be easily taken up and transferred to ecosystems by trophic exchange. Copyright © 2018 Elsevier Ltd. All rights reserved.

Heavy metal: Can molten metal technology turn toxic dross into gold? A study in alchemy, controversy, and green tech

Energy Technology Data Exchange (ETDEWEB)

Lerner, S.

1995-12-31

In a Massachusetts industrial park, inside a renovated helicopter factory, stands a giant, Rube Goldbergesque machine of metal boxes and pipes. Technicians in blue uniforms, hard hats, and safety glasses attend this contraption, watching over the fire at its heart: a cauldron of molten metal, usually iron, heated to some 3,000 degrees Fahrenheit. Hazardous wastes are injected into this molten bath. There, according to its inventor, the metal acts as a catalyst for a chemical reaction that instantly reduces compound molecules to their elemental components. A considerable portion for the wastes thus digested are spit out again in the form of industrial-grade materials, ready for reuse or resale. This article describes both the processing of hazardous wastes by using molten metal to drive reactions that would recover useful materials from hazardous waste and the future possibilities for its use.

Metal ion levels and lymphocyte counts

DEFF Research Database (Denmark)

Penny, Jeannette Ø; Varmarken, Jens-Erik; Ovesen, Ole

2013-01-01

BACKGROUND AND PURPOSE: Wear particles from metal-on-metal arthroplasties are under suspicion for adverse effects both locally and systemically, and the DePuy ASR Hip Resurfacing System (RHA) has above-average failure rates. We compared lymphocyte counts in RHA and total hip arthroplasty (THA) an....../ppb. INTERPRETATION: Circulating T-lymphocyte levels may decline after surgery, regardless of implant type. Metal ions-particularly cobalt-may have a general depressive effect on T- and B-lymphocyte levels. Registered with ClinicalTrials.gov under # NCT01113762.......BACKGROUND AND PURPOSE: Wear particles from metal-on-metal arthroplasties are under suspicion for adverse effects both locally and systemically, and the DePuy ASR Hip Resurfacing System (RHA) has above-average failure rates. We compared lymphocyte counts in RHA and total hip arthroplasty (THA....... RESULTS: The T-lymphocyte counts for both implant types declined over the 2-year period. This decline was statistically significant for CD3(+)CD8(+) in the THA group, with a regression coefficient of -0.04 × 10(9)cells/year (95% CI: -0.08 to -0.01). Regression analysis indicated a depressive effect...

The Infection Rate of Metal-on-Metal Total Hip Replacement Is Higher When Compared to Other Bearing Surfaces as Documented by the Australian Orthopaedic Association National Joint Replacement Registry.

Science.gov (United States)

Huang, Phil; Lyons, Matt; O'Sullivan, Michael

2018-02-01

Despite the well-documented decline in the use of metal-on-metal (MoM) implants over the last decade, there are still controversies regarding whether all MoM implants are created equally. Complications such as elevated serum metal ion levels, aseptic lymphocyte-dominated vasculitis-associated lesion (ALVAL) and pseudotumours have all been well documented, but recent studies suggest increased risk of infection with MoM bearing surfaces. Most of these studies however have small patient numbers. The purpose of this study was to examine the cumulative incidence of revision for infection of MoM bearing surfaces in primary hip arthroplasty at a national and single-surgeon level. Data was collected from the Australian Orthopaedic Association National Joint Replacement Registry, which contains over 98% of all arthroplasties performed in Australia since 2001. The cumulative incidence of revision for infection was extracted at a national level and single-surgeon level. Two hundred seventy-six thousand eight hundred seventy-eight subjects were documented in the Australian registry. The 10-year cumulative percent revision for infection of MoM bearing surfaces in primary total hip replacement (THR) was 2.5% at a national level, compared to 0.8% for other bearing surfaces. The senior author contributed 1755 subjects with 7-year follow-up and a cumulative percent revision for infection of MoM bearing surfaces in primary THR of 36.9%, compared to 2.0% for other bearing surfaces. The cumulative percent of revision of MoM bearing surfaces is higher compared to other bearing surfaces; this is especially pronounced in cumulative percent of revision for infection. There was a higher cumulative percent of revision for infection in MoM bearings surfaces (in particular, large-head MoM) compared to other bearing surfaces at both the national and individual-surgeon level.

Optical magnetism and plasmonic Fano resonances in metal-insulator-metal oligomers.

Science.gov (United States)

Verre, R; Yang, Z J; Shegai, T; Käll, M

2015-03-11

The possibility of achieving optical magnetism at visible frequencies using plasmonic nanostructures has recently been a subject of great interest. The concept is based on designing structures that support plasmon modes with electron oscillation patterns that imitate current loops, that is, magnetic dipoles. However, the magnetic resonances are typically spectrally narrow, thereby limiting their applicability in, for example, metamaterial designs. We show that a significantly broader magnetic response can be realized in plasmonic pentamers constructed from metal-insulator-metal (MIM) sandwich particles. Each MIM unit acts as a magnetic meta-atom and the optical magnetism is rendered quasi-broadband through hybridization of the in-plane modes. We demonstrate that scattering spectra of individual MIM pentamers exhibit multiple Fano resonances and a broad subradiant spectral window that signals the magnetic interaction and a hierarchy of coupling effects in these intricate three-dimensional nanoparticle oligomers.

PENGAMBILAN LOGAM CR6+ DAN CR TOTAL DARI LIMBAH INDUSTRI ELEKTROPLATING SECARA ELEKTROKOGULASI

Directory of Open Access Journals (Sweden)

Muhammad Nizar Pahlevi

2012-10-01

Full Text Available Electroplating industry is a metal coating industry by way of metal precipitate coatings on metal or plastic which is done so that the electrolytic waste containing heavy metals. Electrocoagulation is a process of merging clumps resulting from the flux of electrical current (DC for the extraction of metal compounds contained in wastewater. In this process of reduction and oxidation reactions occur. Where the metal is reduced and the positive electrode (Al will be oxidized to (Al (OH 3 which serves as a coagulant. The purpose of this research to study methods of electrocoagulation using aluminum electrodes and the influence of the length of time stirring and stirring speed of decision-CR6+ levels and total Cr. This electrocoagulation electroplating wastewater with electricity so that the ions are absorbed by the coagulant in waste binder in the release of the electrode and causes the bond between the metal ions with coagulant. Variation of stirrer speed of 200, 400 and 600 rpm, whereas the long stirring time 25, 50 and 75 minutes. Based on test results, after an analysis showed a significant reduction of the levels of total CR6 + and Cr in the electroplating wastes. CR6+ to obtain a decrease of 95.1% at minute 50 and the stirrer speed of 200 rpm, whereas the total Cr obtained a decrease of 82.69% at minute 75 and a stirrer speed of 600 rpm.

Trace metal geochemistry in mangrove sediments and their transfer to mangrove plants (New Caledonia)

International Nuclear Information System (INIS)

Marchand, C.; Fernandez, J.-M.; Moreton, B.

2016-01-01

Because of their physico-chemical inherent properties, mangrove sediments may act as a sink for pollutants coming from catchments. The main objective of this study was to assess the distribution of some trace metals in the tissues of various mangrove plants developing downstream highly weathered ferralsols, taking into account metals partitioning in the sediment. In New Caledonia, mangroves act as a buffer between open-cast mines and the world's largest lagoon. As a result of the erosion of lateritic soils, Ni and Fe concentrations in the sediment were substantially higher than the world average. Whatever the mangrove stand and despite low bioaccumulation and translocations factors, Fe and Ni were also the most abundant metals in the different plant tissues. This low bioaccumulation may be explained by: i) the low availability of metals, which were mainly present in the form of oxides or sulfur minerals, and ii) the root systems acting as barriers towards the transfer of metals to the plant. Conversely, Cu and Zn metals had a greater mobility in the plant, and were characterized by high bioconcentration and translocation factors compared to the other metals. Cu and Zn were also more mobile in the sediment as a result of their association with organic matter. Whatever the metal, a strong decrease of trace metal stock was observed from the landside to the seaside of the mangrove, probably as a result of the increased reactivity of the sediment due to OM enrichment. This reactivity lead to higher dissolution of bearing phases, and thus to the export of dissolved trace metals trough the tidal action. Cu and Zn were the less concerned by the phenomenon probably as a result of higher plant uptake and their restitution to the sediment with litter fall in stands where tidal flushing is limited. - Highlights: • Unusual high concentrations of Fe and Ni were measured in mangrove tissues. • Bioconcentration and translocation factors of Fe, Ni, Co and Mn were low. • Low

Trace metal geochemistry in mangrove sediments and their transfer to mangrove plants (New Caledonia)

Energy Technology Data Exchange (ETDEWEB)

Marchand, C., E-mail: cyril.marchand@ird.fr [Institut de Recherche pour le Développement (IRD), UR 206/UMR 7590 IMPMC, 98848 Nouméa, New Caledonia (France); Fernandez, J.-M.; Moreton, B. [AEL/LEA, 7 rue Loriot de Rouvray, 98800 Nouméa, New Caledonia (France)

2016-08-15

Because of their physico-chemical inherent properties, mangrove sediments may act as a sink for pollutants coming from catchments. The main objective of this study was to assess the distribution of some trace metals in the tissues of various mangrove plants developing downstream highly weathered ferralsols, taking into account metals partitioning in the sediment. In New Caledonia, mangroves act as a buffer between open-cast mines and the world's largest lagoon. As a result of the erosion of lateritic soils, Ni and Fe concentrations in the sediment were substantially higher than the world average. Whatever the mangrove stand and despite low bioaccumulation and translocations factors, Fe and Ni were also the most abundant metals in the different plant tissues. This low bioaccumulation may be explained by: i) the low availability of metals, which were mainly present in the form of oxides or sulfur minerals, and ii) the root systems acting as barriers towards the transfer of metals to the plant. Conversely, Cu and Zn metals had a greater mobility in the plant, and were characterized by high bioconcentration and translocation factors compared to the other metals. Cu and Zn were also more mobile in the sediment as a result of their association with organic matter. Whatever the metal, a strong decrease of trace metal stock was observed from the landside to the seaside of the mangrove, probably as a result of the increased reactivity of the sediment due to OM enrichment. This reactivity lead to higher dissolution of bearing phases, and thus to the export of dissolved trace metals trough the tidal action. Cu and Zn were the less concerned by the phenomenon probably as a result of higher plant uptake and their restitution to the sediment with litter fall in stands where tidal flushing is limited. - Highlights: • Unusual high concentrations of Fe and Ni were measured in mangrove tissues. • Bioconcentration and translocation factors of Fe, Ni, Co and Mn were low. �

ACT: A Benchmark for College Readiness, 2007-2011

Science.gov (United States)

Uzzell, Renata; Lewis, Sharon; Simon, Candace; Palacios, Moses; Guzman, Amilcar; Casserly, Michael

2012-01-01

This report was prepared by the Council of Great City Schools in collaboration with ACT to collect and analyze urban student performance between 2007 and 2011 and to examine student achievement by race and gender. Following is a summary of the study's findings: (1) The total number of ACT test takers increased both nationally and in CGCS districts…

The application of passive sampler (DGT technology for improved understanding of metal behaviour at a marine disposal site

Directory of Open Access Journals (Sweden)

Parker R.

2013-04-01

Full Text Available Metal behaviour and availability at a contaminated dredge material disposal site within UK waters has been investigated using Diffusive Gradient in Thin films (DGT passive sampling technology. Three stations representing contrasting history and presence of maintenance dredge disposal, including a control station outside the disposal site, have been studied and depth profiles of fluxes of different metals (Fe, Mn, Pb, Cu, Cd, Cr, Ni, Zn to the binding gel (Chelex 100 have been derived. Higher flux rates and shallower mobilisation of metals (Mn and Fe to the binding gel were observed at the disposal stations compared to the control station. Here we describe metal mobilization at different depths, linking the remobilization of Fe2+ and Mn2+ to the sediment (resupply of other heavy metals of interest with a focus on Cd, Ni and Pb and as they are on the Water Framework Directive (WFD list of priority substances and OSPAR list of priority pollutants. Results showed that Cd, Pb and Ni exhibited signs of resupply at the sediment-water interface (SWI. There was a potential increased mobilisation and source to the water column of Pb and Ni at the disposal site stations, but there was no Cd source, despite higher total loadings. This information has the potential to improve our current understanding of metal cycles at disposal sites. This work can be used as an indication of likely metal bioavailability and also assist in determining whether the sites act as sources or sinks of heavy metals. This information could assist disposal site monitoring and dredge material licensing.

Resource Conservation and Recovery Act, Part B permit application

International Nuclear Information System (INIS)

1991-02-01

The Waste Isolation Pilot Plant (WIPP) project was authorized by the Department of Energy National Security and Military Applications of Nuclear Energy Authorization Act of 1980 (Public Law 96-164) as a research and development facility to demonstrate the safe, environmentally sound disposal of transuranic (TRU) radioactive wastes derived from the defense activities of the United States. The WIPP facility is owned and operated by the US Department of Energy (DOE). The TRU waste to be received at WIPP consists largely of such items as laboratory glassware and utensils, tools, scrap metal, shielding, personnel protection equipment, and solidified sludges from the treatment of waste water. Approximately 60 percent of this waste is ''mixed,'' that is, it is also contaminated with hazardous waste or hazardous waste constituents as defined by the Resource Conservation and Recovery Act (RCRA) and by the New Mexico Hazardous Waste Management Regulations (HWMR-5). Therefore, emplacement of TRU mixed waste in the WIPP repository is subject to regulation under HWMR-5 and RCRA. The permit application under the Resource Conservation and Recovery Act for WIPP is divided into five volumes. This document, Volume 3, is Appendix C2 continued. This appendix contains information on shipping; inventories of chemicals present in waste; chemical compatibility of wastes; the methodology to determine compatibility; analytical data regarding volatile organic compounds (VOC), metals, and solvents; and a description of sampling programs of waste drum gases

Selective Recovery of Metals from Geothermal Brines

Energy Technology Data Exchange (ETDEWEB)

Ventura, Susanna [SRI International, Menlo Park, CA (United States); Bhamidi, Srinivas [SRI International, Menlo Park, CA (United States); Hornbostel, Marc [SRI International, Menlo Park, CA (United States); Nagar, Anoop [SRI International, Menlo Park, CA (United States); Perea, Elisabeth [SRI International, Menlo Park, CA (United States)

2016-12-16

The objective of this project was to determine the feasibility of developing a new generation of highly selective low-cost ion-exchange resins based on metal-ion imprinted polymers for the separation of metals from geothermal fluids. Expansion of geothermal energy production over the entire U.S. will involve exploitation of low-to-medium temperature thermal waters. Creating value streams from the recovery of critical and near-critical metals from these thermal waters will encourage geothermal expansion. Selective extraction of metals from geothermal fluids is needed to design a cost-effective process for the recovery of lithium and manganese-two near-critical metals with well-known application in the growing lithium battery industry. We have prepared new lithium- and manganese-imprinted polymers in the form of beads by crosslinking polymerization of a metal polymerizable chelate, where the metal acts as a template. Upon leaching out the metal template, the crosslinked polymer is expected to leave cavities defined by the ligand functional group with enhanced selectivity for binding the template metal. We have demonstrated that lithium- and manganese-imprinted polymer beads can be used as selective solid sorbents for the extraction of lithium and manganese from brines. The polymers were tested both in batch extractions and packed bed lab-scale columns at temperatures of 45-100°C. Lithium-imprinted polymers were found to have Li⁺ adsorption capacity as high as 2.8 mg Li⁺/g polymer at 45°C. Manganese-imprinted polymers were found to have a Mn²⁺ adsorption capacity of more than 23 mg Mn²⁺/g polymer at 75°C. The Li⁺ extraction efficiency of the Li-imprinted polymer was found to be more that 95% when a brine containing 390 ppm Li⁺, 410 ppm Na⁺, and 390 ppm K⁺ was passed through a packed bed of the polymer in a lab-scale column at 45°C. In brines containing 360 ppm Li

Magnetic resonance imaging of metal artifact reduction sequences in the assessment of metal-on-metal hip prostheses

Directory of Open Access Journals (Sweden)

Aboelmagd SM

2014-05-01

Full Text Available Sharief M Aboelmagd, Paul N Malcolm, Andoni P Toms Department of Radiology, Norfolk and Norwich University Hospital National Health Service Trust, Norwich, UK Abstract: Recent developments in metal artifact reduction techniques in magnetic resonance (MR have, in large part, been stimulated by the advent of soft tissue complications associated with modern metal-on-metal total hip replacements. Metallic orthopedic implants can result in severe degradation of MR images because ferromagnetic susceptibility causes signal loss, signal pile-up, geometric distortion, and failure of fat suppression. There are several approaches to controlling these susceptibility artifacts. Standard fast spin echo sequences can be adapted by modifying echo times, matrix, receiver bandwidth, slice thickness, and echo trains to minimize frequency encoding misregistration. Short tau inversion recovery and 2-point Dixon techniques are both more resistant to susceptibility artifacts than spectral fat suppression. A number of dedicated metal artifact reduction sequences are now available commercially. The common approach of these multispectral techniques is to generate three dimensional datasets from which the final images are reconstructed. Frequency encoding misregistration is controlled using a variety of techniques, including specific resonant frequency acquisition, view-angle tilting, and phase encoding. Metal artifact reduction MR imaging has been the key to understanding the prevalence, severity, and prognosis of adverse reactions to metal debris in metal-on-metal hip replacements. Conventional radiographs are typically normal or demonstrate minimal change and are unable to demonstrate the often extensive soft tissue abnormalities, which include necrosis, soft tissue masses and fluid collections, myositis, muscle atrophy, tendon avulsions, and osteonecrosis. These MR findings correlate poorly with clinical and serological measures of disease, and therefore MR imaging is

Treatment of suspended solids and heavy metals from urban stormwater runoff by a tree box filter.

Science.gov (United States)

Geronimo, F K F; Maniquiz-Redillas, M C; Tobio, J A S; Kim, L H

2014-01-01

Particulates, inorganic and toxic constituents are the most common pollutants associated with urban stormwater runoff. Heavy metals such as chromium, nickel, copper, zinc, cadmium and lead are found to be in high concentration on paved roads or parking lots due to vehicle emissions. In order to control the rapid increase of pollutant loads in stormwater runoff, the Korean Ministry of Environment proposed the utilization of low impact developments. One of these was the application of tree box filters that act as a bioretention treatment system which executes filtration and sorption processes. In this study, a tree box filter located adjacent to an impervious parking lot was developed to treat suspended solids and heavy metal concentrations from urban stormwater runoff. In total, 11 storm events were monitored from July 2010 to August 2012. The results showed that the tree box filter was highly effective in removing particulates (up to 95%) and heavy metals (at least 70%) from the urban stormwater runoff. Furthermore, the tree box filter was capable of reducing the volume runoff by 40% at a hydraulic loading rate of 1 m/day and below.

Leachability of Arsenic and Heavy Metals from Mine Tailings of Abandoned Metal Mines

Science.gov (United States)

Lim, Mihee; Han, Gi-Chun; Ahn, Ji-Whan; You, Kwang-Suk; Kim, Hyung-Seok

2009-01-01

Mine tailings from an abandoned metal mine in Korea contained high concentrations of arsenic (As) and heavy metals [e.g., As: 67,336, Fe: 137,180, Cu: 764, Pb: 3,572, and Zn: 12,420 (mg/kg)]. US EPA method 6010 was an effective method for analyzing total arsenic and heavy metals concentrations. Arsenic in the mine tailings showed a high residual fraction of 89% by a sequential extraction. In Toxicity Characteristic Leaching Procedure (TCLP) and Korean Standard Leaching Test (KSLT), leaching concentrations of arsenic and heavy metals were very low [e.g., As (mg/L): 0.4 for TCLP and 0.2 for KSLT; cf. As criteria (mg/L): 5.0 for TCLP and 1.5 for KSLT]. PMID:20049231

Distribution of heavy metals in riverine soils and sediments of the Turia River basin.

Science.gov (United States)

Andreu, Vicente; Gimeno-García, Eugenia; Pascual, Juan Antonio

2014-05-01

Water is a scarce and contested good, and a primary need for the population all over. Rivers are one of the mainsources of freshwater to people but, in the same way, receive both point source and difuse pollution, usually frorm wastewaters and agriculture. However, they are not independent bodies but they influence different associated ecosystems that compound the catchment. Soils of the river banks often acts as the last phase of the diffuse contamination pathways, favouring the contaminants input to the river waters. In this sense, the fluvial sedimentary phase usually acts as a sink of pollutants. Sediments can work as resevoirs that accumulate contaminants fixing them or allowing their decomposition or metabolization. However, environmental or human induced, such as variations in water pH, increases in the turbulence or intensity of the water flow, etc.could favour their release to the environment. In this work, the incidence and distribution of seven heavy metals was monitored in riverine soils and sediments of the Turia River. Along the river course, 22 zones were selected for sampling according different lithologies, land uses, size of populations and the proximity to waste waters treatment plants (WWTPs), from the headwaters to the mouth. The selected metals (Cd, Co, Cr, Cu, Pb, Ni and Zn) were analysed to determine its total and extractable contents in the sediments. Total content of metals was extracted by microwave acid digestion and the extractable fraction by treatment with EDTA. Atomic Absorption Spectrometry, using graphite furnace when necessary, was used for the determination of all metals. Highest values for sediments were mainly observed in zones 10 and 22, close to urban areas, reaching values of 172.86 mg/kg for Pb, or 58.34 mg/kg for Cr. However, zone 2 near in the headwaters of the Alfambra River and supposedly of reference for the River authorities shows the highest values of zinc with 96.96 mg/kg. Regarding the available

Disorder and conductivity of organic metal

International Nuclear Information System (INIS)

Bouffard, Serge

1982-02-01

At high temperature, quasi-one-dimensional organic conductors are metallic; at low temperature, the electron gas instabilities drive either a metal to insulator transition or a metal to superconductor transition. Precursors of these 3-D ordering could be appear at higher temperature. A study of the effects of irradiation induced defects on a few organic complexes has shown that defects are produced by radiolitic process. Their concentration can be easily deduced from resistivity measurement at room temperature. In the metallic state, the defects act as strong potentials which break the conducting chains and force the electron to jump to the neighbourg stack. The defects produce a mixing between longitudinal and transverse conductivities. While, it is the 3-D effect of the defects which pins the charge density waves and thus the 3-D ordering can not be acheived: the metal to insulator transition is destroyed, the metallic state is stabilized. In the same time, the fluctuative conductivity is suppress. The superconducting regime has been found to be extremely sensitive to irradiation induced defects. Thus we can demonstrate that the 1-D superconducting fluctuations contribute to the conductivity and that the transition temperature is correlated to the 3-D superconducting fluctuations. [fr

Some stars are totally metal: a new mechanism driving dust across star-forming clouds, and consequences for planets, stars, and galaxies

International Nuclear Information System (INIS)

Hopkins, Philip F.

2014-01-01

Dust grains in neutral gas behave as aerodynamic particles, so they can develop large local density fluctuations entirely independent of gas density fluctuations. Specifically, gas turbulence can drive order-of-magnitude 'resonant' fluctuations in the dust density on scales where the gas stopping/drag timescale is comparable to the turbulent eddy turnover time. Here we show that for large grains (size ≳ 0.1 μm, containing most grain mass) in sufficiently large molecular clouds (radii ≳ 1-10 pc, masses ≳ 10 4 M ☉ ), this scale becomes larger than the characteristic sizes of prestellar cores (the sonic length), so large fluctuations in the dust-to-gas ratio are imprinted on cores. As a result, star clusters and protostellar disks formed in large clouds should exhibit significant abundance spreads in the elements preferentially found in large grains (C, O). This naturally predicts populations of carbon-enhanced stars, certain highly unusual stellar populations observed in nearby open clusters, and may explain the 'UV upturn' in early-type galaxies. It will also dramatically change planet formation in the resulting protostellar disks, by preferentially 'seeding' disks with an enhancement in large carbonaceous or silicate grains. The relevant threshold for this behavior scales simply with cloud densities and temperatures, making straightforward predictions for clusters in starbursts and high-redshift galaxies. Because of the selective sorting by size, this process is not necessarily visible in extinction mapping. We also predict the shape of the abundance distribution—when these fluctuations occur, a small fraction of the cores may actually be seeded with abundances Z ∼ 100 (Z) such that they are almost 'totally metal' (Z ∼ 1)! Assuming the cores collapse, these totally metal stars would be rare (1 in ∼10 4 in clusters where this occurs), but represent a fundamentally new stellar evolution channel.

Catalytic total hydrodeoxygenation of biomass-derived polyfunctionalized substrates to alkanes.

Science.gov (United States)

Nakagawa, Yoshinao; Liu, Sibao; Tamura, Masazumi; Tomishige, Keiichi

2015-04-13

The total hydrodeoxygenation of carbohydrate-derived molecules to alkanes, a key reaction in the production of biofuel, was reviewed from the aspect of catalysis. Noble metals (or Ni) and acid are the main components of the catalysts, and group 6 or 7 metals such as Re are sometimes added as modifiers of the noble metal. The main reaction route is acid-catalyzed dehydration plus metal-catalyzed hydrogenation, and in some systems metal-catalyzed direct CO dissociation is involved. The appropriate active metal, acid strength, and reaction conditions depend strongly on the reactivity of the substrate. Reactions that use Pt or Pd catalysts supported on Nb-based acids or relatively weak acids are suitable for furanic substrates. Carbohydrates themselves and sugar alcohols undergo CC dissociation easily. The systems that use metal-catalyzed direct CO dissociations can give a higher yield of the corresponding alkane from carbohydrates and sugar alcohols. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Metal flows of the circumgalactic medium, and the metal budget in galactic haloes

Science.gov (United States)

Muratov, Alexander L.; Kereš, Dušan; Faucher-Giguère, Claude-André; Hopkins, Philip F.; Ma, Xiangcheng; Anglés-Alcázar, Daniel; Chan, T. K.; Torrey, Paul; Hafen, Zachary H.; Quataert, Eliot; Murray, Norman

2017-07-01

We present an analysis of the flow of metals through the circumgalactic medium (CGM) in the Feedback in Realistic Environments (FIRE) simulations of galaxy formation, ranging from isolated dwarfs to L* galaxies. We find that nearly all metals produced in high-redshift galaxies are carried out in winds that reach 0.25Rvir. When measured at 0.25Rvir the metallicity of outflows is slightly higher than the interstellar medium (ISM) metallicity. Many metals thus reside in the CGM. Cooling and recycling from this reservoir determine the metal budget in the ISM. The outflowing metal flux decreases by a factor of ˜2-5 between 0.25Rvir and Rvir. Furthermore, outflow metallicity is typically lower at Rvir owing to dilution of the remaining outflow by metal-poor material swept up from the CGM. The inflow metallicity at Rvir is generally low, but outflow and inflow metallicities are similar in the inner halo. At low redshift, massive galaxies no longer generate outflows that reach the CGM, causing a divergence in CGM and ISM metallicity. Dwarf galaxies continue to generate outflows, although they preferentially retain metal ejecta. In all but the least massive galaxy considered, a majority of the metals are within the halo at z = 0. We measure the fraction of metals in CGM, ISM and stars, and quantify the thermal state of CGM metals in each halo. The total amount of metals in the low-redshift CGM of two simulated L* galaxies is consistent with estimates from the Cosmic Origin Spectrograph haloes survey, while for the other two it appears to be lower.

75 FR 38983 - Magnesium Metal From the People's Republic of China and the Russian Federation: Final Results of...

Science.gov (United States)

2010-07-07

... DEPARTMENT OF COMMERCE International Trade Administration [A-570-896, A-821-819] Magnesium Metal... sunset reviews of the antidumping duty orders on magnesium metal from the People's Republic of China..., as amended (``the Act''). On March 16, 2010, US Magnesium LLS, the petitioner in the magnesium metal...

Roles for root iron plaque in sequestration and uptake of heavy metals and metalloids in aquatic and wetland plants.

Science.gov (United States)

Tripathi, Rudra D; Tripathi, Preeti; Dwivedi, Sanjay; Kumar, Amit; Mishra, Aradhana; Chauhan, Puneet S; Norton, Gareth J; Nautiyal, Chandra S

2014-10-01

Toxic metal(loid) contamination of soil and sediment poses long term risk to soil and human health through plant-human or plant-animal-human food chain pathways. Iron plaque (IP) formation is frequent in aquatic and wetland plant species and is responsible for the sequestration of various metal(loids). The presence of IP may act as a buffer or barrier and may thus enhance or reduce the uptake of potentially phytotoxic metals and metalloids by plants. If IP acts as a barrier, then low IP producing macrophytes/aquatic plants may be better accumulators of toxic metals and may find use in constructed wetlands for remediation of pollutants, while high IP forming edible plant species could be safer for human consumption. Conversely, if IP acts as a buffer for mineral nutrients and toxic elements then those cultivars may be rich in nutrients, but may also cause toxicity. However, an ecotoxicological risk is also inevitable if IP rich macrophyte roots containing heavy metals are consumed by herbivores. In this review, we summarize the current understanding about the role of IP in metal and metalloid sequestration, uptake, and transport. Furthermore, we will address the role of root IP in Oryza sativa for arsenic (As) sequestration leading to lower grain As translocation, reducing the risk of human exposure.

The Catalytic Enantioselective Total Synthesis of (+)‐Liphagal

DEFF Research Database (Denmark)

Day, Joshua J.; McFadden, Ryan M.; Virgil, Scott C.

2011-01-01

Ring a ding: The first catalytic enantioselective total synthesis of the meroterpenoid natural product (+)-liphagal is disclosed. The approach showcases a variety of technology including enantioselective enolate alkylation, a photochemical alkyne-alkene [2+2] reaction, microwaveassisted metal...

Photochemical Hydrogen Doping Induced Embedded Two-Dimensional Metallic Channel Formation in InGaZnO at Room Temperature.

Science.gov (United States)

Kim, Myeong-Ho; Lee, Young-Ahn; Kim, Jinseo; Park, Jucheol; Ahn, Seungbae; Jeon, Ki-Joon; Kim, Jeong Won; Choi, Duck-Kyun; Seo, Hyungtak

2015-10-27

The photochemical tunability of the charge-transport mechanism in metal-oxide semiconductors is of great interest since it may offer a facile but effective semiconductor-to-metal transition, which results from photochemically modified electronic structures for various oxide-based device applications. This might provide a feasible hydrogen (H)-radical doping to realize the effectively H-doped metal oxides, which has not been achieved by thermal and ion-implantation technique in a reliable and controllable way. In this study, we report a photochemical conversion of InGaZnO (IGZO) semiconductor to a transparent conductor via hydrogen doping to the local nanocrystallites formed at the IGZO/glass interface at room temperature. In contrast to thermal or ionic hydrogen doping, ultraviolet exposure of the IGZO surface promotes a photochemical reaction with H radical incorporation to surface metal-OH layer formation and bulk H-doping which acts as a tunable and stable highly doped n-type doping channel and turns IGZO to a transparent conductor. This results in the total conversion of carrier conduction property to the level of metallic conduction with sheet resistance of ∼16 Ω/□, room temperature Hall mobility of 11.8 cm(2) V(-1) sec(-1), the carrier concentration at ∼10(20) cm(-3) without any loss of optical transparency. We demonstrated successful applications of photochemically highly n-doped metal oxide via optical dose control to transparent conductor with excellent chemical and optical doping stability.

Effects of past sewage sludge additions on heavy metal availability in light textured soils: implications for crop yields and metal uptakes

International Nuclear Information System (INIS)

Bhogal, A.; Nicholson, F.A.; Chambers, B.J.; Shepherd, M.A.

2003-01-01

Topsoil extractable zinc and copper concentrations are a good indicator of metal bioavailability to crops. - The effect of heavy metal additions in past sewage sludge applications on soil metal availability and the growth and yield of crops was evaluated at two sites in the UK. At Gleadthorpe, sewage sludges enriched with salts of zinc (Zn), copper (Cu) and nickel (Ni) had been applied to a loamy sand in 1982 and additionally naturally contaminated Zn and Cu sludge cakes in 1986. At Rosemaund, sewage sludges naturally contaminated with Zn, Cu, Ni and chromium (Cr) had been applied in 1968-1971 to a sandy loam. From 1994 to 1997, the yields of both cereals and legumes at Gleadthorpe were up to 3 t/ha lower than the no-sludge control where total topsoil Zn and Cu concentrations exceeded 200 and 120 mg/kg, respectively, but only when topsoil ammonium nitrate extractable metal levels also exceeded 40 mg/kg Zn and 0.9 mg/kg Cu. At Rosemaund, yields were only decreased where total topsoil Cu concentrations exceeded 220 mg/kg or 0.7 mg/kg ammonium nitrate extractable Cu. These results demonstrate the importance of measuring extractable as well as total heavy metal concentrations in topsoils when assessing likely effects on plant yields and metal uptakes, and setting soil quality criteria

Impurity Trapping of Positive Muons in Metals

CERN Multimedia

2002-01-01

Polarized positive muons are implanted into metal samples. In an applied magnetic field the muon spin precession is studied. The line width in the precession frequency spectrum gives information about the static and dynamic properties of muons in a metal lattice. At temperatures where the muon is immobile within its lifetime the line width gives information about the site of location. At temperatures where the muon is mobile, the line width gives information on the diffusion process. It is known from experiments on quasi-elastic neutron scattering on hydrogen in niobium that interstitial impurities like nitrogen tend to act as traps for hydrogen. These trapping effects have now been studied systematically for muons in both f.c.c. metals (aluminium and copper) and b.c.c. metals (mainly niobium). Direct information on the trapping rates and the nature of the diffusion processes can be obtained since the muonic lifetime covers a time range where many of these processes occur.\\\\ \\\\ Mathematical models are set up ...

Optical transmission theory for metal-insulator-metal periodic nanostructures

Directory of Open Access Journals (Sweden)

Blanchard-Dionne Andre-Pierre

2016-11-01

Full Text Available A semi-analytical formalism for the optical properties of a metal-insulator-metal periodic nanostructure using coupled-mode theory is presented. This structure consists in a dielectric layer in between two metallic layers with periodic one-dimensional nanoslit corrugation. The model is developed using multiple-scattering formalism, which defines transmission and reflection coefficients for each of the interface as a semi-infinite medium. Total transmission is then calculated using a summation of the multiple paths of light inside the structure. This method allows finding an exact solution for the transmission problem in every dimension regime, as long as a sufficient number of diffraction orders and guided modes are considered for the structure. The resonant modes of the structure are found to be related to the metallic slab only and to a combination of both the metallic slab and dielectric layer. This model also allows describing the resonant behavior of the system in the limit of a small dielectric layer, for which discontinuities in the dispersion curves are found. These discontinuities result from the out-of-phase interference of the different diffraction orders of the system, which account for field interaction for both inner interfaces of the structure.

Electronic structure, bonding and chemisorption in metallic hydrides

International Nuclear Information System (INIS)

Ward, J.W.

1980-01-01

Problems that can arise during the cycling steps for a hydride storage system usually involve events at surfaces. Chemisorption and reaction processes can be affected by small amounts of contaminants that may act as catalytic poisons. The nature of the poisoning process can vary greatly for the different metals and alloys that form hydrides. A unifying concept is offered, which satisfactorily correlates many of the properties of transition-metal, rare-earth and actinide hydrides. The metallic hydrides can be differentiated on the basis of electronegativity, metallic radius (valence) and electronic structure. For those systems where there are d (transition metals) or f (early actinides) electrons near the Fermi level a broad range of chemical and catalytic behaviors are found, depending on bandwidth and energy. The more electropositive metals (rare-earths, actinides, transition metals with d > 5) dissolve hydrogen and form hydrides by an electronically somewhat different process, and as a class tend to adsorb electrophobic molecules. The net charge-transfer in either situation is subtle; however, the small differences are responsible for many of the observed structural, chemical, and catalytic properties in these hydride systems

Phytoremediation of heavy and transition metals aided by legume-rhizobia symbiosis

DEFF Research Database (Denmark)

Hao, X.; Taghavi, S.; Xie, P.

2014-01-01

Legumes are important for nitrogen cycling in the environment and agriculture due to the ability of nitrogen fixation by rhizobia. In this review, we introduce an important and potential role of legume-rhizobia symbiosis in aiding phytoremediation of some metal contaminated soils as various legumes...... have been found to be the dominant plant species in metal contaminated areas. Resistant rhizobia used for phytoremediation could act on metals directly by chelation, precipitation, transformation, biosorption and accumulation. Moreover, the plant growth promoting (PGP) traits of rhizobia including...... is not clear. Therefore, to obtain the maximum benefits from legumes assisted by rhizobia for phytoremediation of metals, it is critical to have a good understanding of interactions between PGP traits, the symbiotic plant-rhizobia relationship and metals....

An Examination of the Association of Selected Toxic Metals with Total and Central Obesity Indices: NHANES 99-02

Directory of Open Access Journals (Sweden)

Douglas M. Ruden

2010-08-01

Full Text Available It is conceivable that toxic metals contribute to obesity by influencing various aspects of metabolism, such as by substituting for essential micronutrients and vital metals, or by inducing oxidative stress. Deficiency of the essential metal zinc decreases adiposity in humans and rodent models, whereas deficiencies of chromium, copper, iron, and magnesium increases adiposity. This study utilized the NHANES 99-02 data to explore the association between waist circumference and body mass index with the body burdens of selected toxic metals (barium, cadmium, cobalt, cesium, molybdenum, lead, antimony, thallium, and tungsten. Some of the associations were significant direct relationships (barium and thallium, and some of the associations were significant inverse relationships (cadmium, cobalt, cesium, and lead. Molybdenum, antimony, and tungsten had mostly insignificant associations with waist circumference and body mass index. This is novel result for most of the toxic metals studied, and a surprising result for lead because high stored lead levels have been shown to correlate with higher rates of diabetes, and obesity may be a key risk factor for developing diabetes. These associations suggest the possibility that environmental exposure to metals may contribute to variations in human weight gain/loss. Future research, such as prospective studies rather than the cross-sectional studies presented here, is warranted to confirm these findings.

An examination of the association of selected toxic metals with total and central obesity indices: NHANES 99-02.

Science.gov (United States)

Padilla, Miguel A; Elobeid, Mai; Ruden, Douglas M; Allison, David B

2010-09-01

It is conceivable that toxic metals contribute to obesity by influencing various aspects of metabolism, such as by substituting for essential micronutrients and vital metals, or by inducing oxidative stress. Deficiency of the essential metal zinc decreases adiposity in humans and rodent models, whereas deficiencies of chromium, copper, iron, and magnesium increases adiposity. This study utilized the NHANES 99-02 data to explore the association between waist circumference and body mass index with the body burdens of selected toxic metals (barium, cadmium, cobalt, cesium, molybdenum, lead, antimony, thallium, and tungsten). Some of the associations were significant direct relationships (barium and thallium), and some of the associations were significant inverse relationships (cadmium, cobalt, cesium, and lead). Molybdenum, antimony, and tungsten had mostly insignificant associations with waist circumference and body mass index. This is novel result for most of the toxic metals studied, and a surprising result for lead because high stored lead levels have been shown to correlate with higher rates of diabetes, and obesity may be a key risk factor for developing diabetes. These associations suggest the possibility that environmental exposure to metals may contribute to variations in human weight gain/loss. Future research, such as prospective studies rather than the cross-sectional studies presented here, is warranted to confirm these findings.

Evaluation of Accelerated Ageing Tests for Metallic and Non-Metallic Graffiti Paints Applied to Stone

Directory of Open Access Journals (Sweden)

Patricia Sanmartín

2017-10-01

Full Text Available Graffiti are increasingly observed on urban and peri-urban buildings and their removal requires a huge financial outlay by local governments and agencies. Graffiti are not usually removed immediately, but rather over the passage of time, viz. months or even years. In this study, which forms part of a wider research project on graffiti removal, different methods (gravimetric analysis, examination of digital images, colour and infrared measurements were used to evaluate the performance of accelerated ageing tests (involving exposure to humidity, freeze-thawing cycles and NaCl and Na2SO4 salts for graffiti painted on stone. Silver (metallic and black (non-metallic graffiti spray paints were applied to two types of igneous rock (granite and rhyolitic ignimbrite and one sedimentary rock (fossiliferous limestone, i.e., biocalcarenite. The metallic and non-metallic graffiti spray paints acted differently on the stone surfaces, both chemically and physically. Older graffiti were found to be more vulnerable to weathering agents. The ageing test with NaCl and particularly Na2SO4, both applied to granite, proved the most severe on the paints, yielding more detrimental and faster artificial ageing of the type of material under study.

Trace metal speciation: Finally, correctly addressing trace metal issues

International Nuclear Information System (INIS)

Donard, O.F.X.

2001-01-01

The history of the development of trace metal speciation was discussed and the reasons behind the relatively slow widespread acceptance of its importance were presented. Partially, this was due to the lack of availability of commercial instrumentation and partly to the drive towards improving sensitivity in analytical chemistry which had focused attention on total concentration determinations. The sophistication and control of analytical instrumentation is now such that the spotlight must be turned onto the chemical species of an element present in a sample since this is what governs its behaviour in the biosphere. Indeed, several companies are currently considering the introduction of instrumentation specifically designed for metal species determination

78 FR 20912 - Clean Water Act: Availability of List Decisions

Science.gov (United States)

2013-04-08

... ENVIRONMENTAL PROTECTION AGENCY [FRL-9798-8] Clean Water Act: Availability of List Decisions.... SUMMARY: The Clean Water Act requires that States periodically submit, and EPA approve or disapprove... are not stringent enough to attain or maintain State water quality standards and for which total...

Self-Expandable Metal Stent Placement for Closure of a Leak after Total Gastrectomy for Gastric Cancer: Report on Three Cases and Review of the Literature

Directory of Open Access Journals (Sweden)

Dario Raimondo

2014-01-01

Full Text Available In the setting of the curative oncological surgery, the gastric surgery is exposed to complicated upper gastrointestinal leaks, and consequently the management of this problem has become more critically focused than was previously possible. We report here three cases of placement of a partially silicone-coated SEMS (Evolution Controlled Release Esophageal Stent System, Cook Medical, Winston-Salem, NC, USA in patients who underwent total gastrectomy with Roux-en-Y end-to-side esophagojejunostomy for a gastric adenocarcinoma. The promising results of our report, despite the small number of patients, suggest that early stenting (through a partially silicone-coated SEMS is a feasible alternative to surgical treatment in this subset of patients. In fact, in the treatment of leakage after total gastrectomy, plastic stents and totally covered metallic stents may not adhere sufficiently to the esophagojejunal walls and, as a result, migrate beyond the anastomosis. However, prospective studies with a larger number of patients might assess the real effectiveness and safety of this procedure.

Heavy metals in surface sediments of the Jialu River, China: their relations to environmental factors.

Science.gov (United States)

Fu, Jie; Zhao, Changpo; Luo, Yupeng; Liu, Chunsheng; Kyzas, George Z; Luo, Yin; Zhao, Dongye; An, Shuqing; Zhu, Hailiang

2014-04-15

This work investigated heavy metal pollution in surface sediments of the Jialu River, China. Sediment samples were collected at 19 sites along the river in connection with field surveys and the total concentrations were determined using atomic fluorescence spectrometer and inductively coupled plasma optical emission spectrometer. Sediment samples with higher metal concentrations were collected from the upper reach of the river, while sediments in the middle and lower reaches had relatively lower metal concentrations. Multivariate techniques including Pearson correlation, hierarchical cluster and principal components analysis were used to evaluate the metal sources. The ecological risk associated with the heavy metals in sediments was rated as moderate based on the assessments using methods of consensus-based Sediment Quality Guidelines, Potential Ecological Risk Index and Geo-accumulation Index. The relations between heavy metals and various environmental factors (i.e., chemical properties of sediments, water quality indices and aquatic organism indices) were also studied. Nitrate nitrogen, total nitrogen, and total polycyclic aromatic hydrocarbons concentrations in sediments showed a co-release behavior with heavy metals. Ammonia nitrogen, total nitrogen, orthophosphate, total phosphate and permanganate index in water were found to be related to metal sedimentation. Heavy metals in sediments posed a potential impact on the benthos community. Copyright © 2014 Elsevier B.V. All rights reserved.

Towards nanoprinting with metals on graphene

Science.gov (United States)

Melinte, G.; Moldovan, S.; Hirlimann, C.; Liu, X.; Bégin-Colin, S.; Bégin, D.; Banhart, F.; Pham-Huu, C.; Ersen, O.

2015-08-01

Graphene and carbon nanotubes are envisaged as suitable materials for the fabrication of the new generation of nanoelectronics. The controlled patterning of such nanostructures with metal nanoparticles is conditioned by the transfer between a recipient and the surface to pattern. Electromigration under the impact of an applied voltage stands at the base of printing discrete digits at the nanoscale. Here we report the use of carbon nanotubes as nanoreservoirs for iron nanoparticles transfer on few-layer graphene. An initial Joule-induced annealing is required to ensure the control of the mass transfer with the nanotube acting as a `pen' for the writing process. By applying a voltage, the tube filled with metal nanoparticles can deposit metal on the surface of the graphene sheet at precise locations. The reverse transfer of nanoparticles from the graphene surface to the nanotube when changing the voltage polarity opens the way for error corrections.

Co-percolation to tune conductive behaviour in dynamical metallic nanowire networks.

Science.gov (United States)

Fairfield, J A; Rocha, C G; O'Callaghan, C; Ferreira, M S; Boland, J J

2016-11-03

Nanowire networks act as self-healing smart materials, whose sheet resistance can be tuned via an externally applied voltage stimulus. This memristive response occurs due to modification of junction resistances to form a connectivity path across the lowest barrier junctions in the network. While most network studies have been performed on expensive noble metal nanowires like silver, networks of inexpensive nickel nanowires with a nickel oxide coating can also demonstrate resistive switching, a common feature of metal oxides with filamentary conduction. However, networks made from solely nickel nanowires have high operation voltages which prohibit large-scale material applications. Here we show, using both experiment and simulation, that a heterogeneous network of nickel and silver nanowires allows optimization of the activation voltage, as well as tuning of the conduction behavior to be either resistive switching, memristive, or a combination of both. Small percentages of silver nanowires, below the percolation threshold, induce these changes in electrical behaviour, even for low area coverage and hence very transparent films. Silver nanowires act as current concentrators, amplifying conductivity locally as shown in our computational dynamical activation framework for networks of junctions. These results demonstrate that a heterogeneous nanowire network can act as a cost-effective adaptive material with minimal use of noble metal nanowires, without losing memristive behaviour that is essential for smart sensing and neuromorphic applications.

75 FR 20351 - Clean Water Act Section 303(d): Availability of One Total Maximum Daily Load (TMDL) in Arkansas

Science.gov (United States)

2010-04-19

... ENVIRONMENTAL PROTECTION AGENCY [FRL-9139-5] Clean Water Act Section 303(d): Availability of One...: Notice of availability. SUMMARY: This notice announces the availability of the administrative record file... in the State of Arkansas under Section 303(d) of the Clean Water Act (CWA). This TMDL was completed...

Determinación de la concentración de sólidos suspendidos totales (SST y metales pesados en la cuenca del Río Morote, Nicoya, Guanacaste.

Directory of Open Access Journals (Sweden)

Ricardo Sánchez Murillo

2016-03-01

Full Text Available The Total Suspended Solids (TTS and heavy metal concentrations of Morote River Basin were determined. The project includedsix sampling campaigns between April 2003 and May 2005. The sampling points in the Morote River were selected from the high basin to the mouth of the river in the Gulf of Nicoya. During the rainy season the concentrations of TTS exceed the value of 200 mg/L in the mouth of the river. An enrichment of the sediments was found from the river-bed with heavy metals such as copper, cadmium, nickel and iron but enrichment with lead was not found. In the dry season the concentration of zinc was colose to the allotted maximum value (200 mg/kg which has been established for the Envoronmental Protection Agency of the United States (EPA.

Impact of the Prestige oil spill on marsh soils: Relationship between heavy metal, sulfide and total petroleum hydrocarbon contents at the Villarrube and Lires marshes (Galicia, Spain); Impacto de la marea negra del Prestige en suelos de marisma: relacion entre los contenidos de metales pesados, sulfuros e hidrocarburos en las marismas de Villarrube y Lires (Galicia, Espana)

Energy Technology Data Exchange (ETDEWEB)

Andrade, L.; Marcet, P.; Covelo, E.F.; Vega, F.A. [Department of Vegetable Biology and Soil Science, Vigo (Spain); Fernandez-Feal, L.; Fernandez-Feal, C. [Escuela Politecnica Superior, Universidad de la Coruna, Ferrol (Spain)

2004-09-15

The objectives of this study were to determine the effect of the Prestige oil spill on the total petroleum hydrocarbons and heavy metal contents of soils in two marshes (Lires and Villarrube, Galicia, Spain) and the relationship between their oxidation-reduction potential and the solubility of heavy metals with sulfide and sulfate contents. Soil samples were taken from polluted and unpolluted areas and their petroleum hydrocarbon contents, heavy metal contents and other chemical characteristics were measured. The soils affected by the oil spill show remarkable contents of Cr, Cu, Ni, Pb and V. The Lires marsh soils are more affected by fuel oil than Villarrube marsh. The effects of the contaminating agents on the soils reach distances of up to 500 m from the coastline. In the first 400 m, there are important spatial variations because the fuel oil penetrated into the soils through tidal action and not directly. The Cr, Cu, Ni, Pb and V contents of polluted soils were between 50 and 200 times higher than those of their unpolluted counterparts and the background concentrations in Galician coastal sediments. In the case of Cr, Cu, Ni, Pb and V, their origin through the fuel oil was corroborated by the high correlation (r > 0.90) between the concentrations of these metals and the total petroleum hydrocarbon content of the polluted soils, which shows the combined addition of these metals through the fuel oil. [Spanish] Los objetivos de este trabajo fueron determinar el efecto de la marea negra del buque tanque Prestige en el contenido total de hidrocarburos y de metales pesados en suelos de dos marismas (Lires y Villarrube, Galicia, Espana) y la relacion entre el potencial de oxidacion-reduccion y la solubilidad de los metales pesados con los contenidos de sulfuros y de sulfatos. Se tomaron muestras de suelos de las zonas contaminadas y no contaminadas y se determinaron diversas caracteristicas quimicas, el contenido total de hidrocarburos y de metales pesados. Los

The Synergy between Meteorological Parameters and the Total ...

African Journals Online (AJOL)

because of its origin from mostly non-urban areas that ... particles in the air are readily removed by falling rain drop ..... Their physics and Physical ... Mass. Concentrations and Metals Speciation of PM2.5. PM10 and total suspended solids in ...

Bilayer–metal assisted chemical etching of silicon microwire arrays for photovoltaic applications

Directory of Open Access Journals (Sweden)

R. W. Wu

2016-02-01

Full Text Available Silicon microwires with lateral dimension from 5 μm to 20 μm and depth as long as 20 μm are prepared by bilayer metal assisted chemical etching (MaCE. A bilayer metal configuration (Metal 1 / Metal 2 was applied to assist etching of Si where metal 1 acts as direct catalyst and metal 2 provides mechanical support. Different metal types were investigated to figure out the influence of metal catalyst on morphology of etched silicon. We find that silicon microwires with vertical side wall are produced when we use Ag/Au bilayer, while cone–like and porous microwires formed when Pt/Au is applied. The different micro-/nano-structures in as-etched silicon are demonstrated to be due to the discrepancy of work function of metal catalyst relative to Si. Further, we constructed a silicon microwire arrays solar cells in a radial p–n junction configurations in a screen printed aluminum paste p–doping process.

Risk factors for total hip arthroplasty aseptic revision.

Science.gov (United States)

Khatod, Monti; Cafri, Guy; Namba, Robert S; Inacio, Maria C S; Paxton, Elizabeth W

2014-07-01

The purpose of this study was to evaluate patient, operative, implant, surgeon, and hospital factors associated with aseptic revision after primary THA in patients registered in a large US Total Joint Replacement Registry. A total of 35,960 THAs registered from 4/2001-12/2010 were evaluated. The 8-year survival rate was 96.7% (95% CI 96.4%-97.0%). Females had a higher risk of aseptic revision than males. Hispanic and Asian patients had a lower risk of revision than white patients. Ceramic-on-ceramic, ceramic-on-conventional polyethylene, and metal-on-conventional polyethylene bearing surfaces had a higher risk of revision than metal-on-highly cross-linked polyethylene. Body mass index, health status, diabetes, diagnosis, fixation, approach, bilateral procedures, head size, surgeon fellowship training, surgeon and hospital volume were not revision risk factors. Copyright © 2014 Elsevier Inc. All rights reserved.

Biofilms as bio-indicator for polluted waters? Total reflection X-ray fluorescence analysis of biofilms of the Tisza river (Hungary)

Energy Technology Data Exchange (ETDEWEB)

Mages, Margarete; Ovari, Mihaly; Tuempling, Wolf v. [Department of Inland Water Research Magdeburg, UFZ Centre for Environmental Research Leipzig-Halle, Brueckstrasse 3a, 39114, Magdeburg (Germany); Kroepfl, Krisztina [Department of Chemical Technology and Environmental Chemistry, Eoetvoes University, Pazmany Peter setany 1/A, 1117, Budapest (Hungary)

2004-02-01

The aim of this work was to investigate the heavy metal accumulation by natural biofilms living in the catchment area of the Tisza river in Hungary, as well as in biofilms cultivated in vitro. Laboratory tests have demonstrated that metals can be adsorbed on biofilms, depending on their concentration and on the availability of free sorptive places. Biofilms were cultivated in vitro in natural freshwater from the Saale river, Germany. After reaching the plateau phase, Cu was added to reach a concentration of 100 {mu}g/L. An increase of its mass fraction in the biofilm was observed, which caused the decrease of the concentration in the water phase. Unfortunately, the reactor wall was also found to act as adsorbent for Cu. More detailed results of our in vitro experiments will be published in a forthcoming paper. Naturally grown biofilm samples from exposed as well as background places at the Hungarian rivers Szamos and Tisza were collected in 2000 and 2002 after the cyanide spill, and analysed using total reflection X-ray fluorescence analysis (TXRF). Metal mass fraction differences as high as two orders of magnitude were found between polluted and unpolluted (background) sampling points. Extremely high concentration values, e.g. 5600 {mu}g/g Zn in biofilm, were found at highly polluted sampling points. This means an enrichment factor of ca. 10,000 compared to the water phase. (orig.)

Transfer and accumulation of metals in a soil-diet-wood mouse food chain along a metal pollution gradient

International Nuclear Information System (INIS)

Rogival, Damien; Scheirs, Jan; Blust, Ronny

2007-01-01

We studied the accumulation and transfer of As, Cd, Cu, Pb and Zn in the compartments of a soil-diet-wood mouse (Apodemus sylvaticus) food chain at five sites located along a metal pollution gradient. We observed a clear gradient in metal exposure at increasing distance from the smelter in all compartments of the food chain for the non-essential metals. The gradient was less clear or absent for the essential metals in acorn and mice target tissues. Regression analysis showed overall strong relationships within the soil-diet and diet-wood mouse compartments for the non-essential metals, while relationships for the essential metals were weak or absent. Total metal in soil appeared as a better predictor for the diet metal content than the available metal fraction. Our results suggest a more important transfer of non-essential elements through the food chain than essential elements, which is probably a consequence of homeostatic control of the latter group. - Non-essential metal transfer through a soil-diet-wood mouse food chain is more important than essential metal transfer

Metal and alloy nanoparticles by amine-borane reduction of metal salts by solid-phase synthesis: atom economy and green process.

Science.gov (United States)

Sanyal, Udishnu; Jagirdar, Balaji R

2012-12-03

A new solid state synthetic route has been developed toward metal and bimetallic alloy nanoparticles from metal salts employing amine-boranes as the reducing agent. During the reduction, amine-borane plays a dual role: acts as a reducing agent and reduces the metal salts to their elemental form and simultaneously generates a stabilizing agent in situ which controls the growth of the particles and stabilizes them in the nanosize regime. Employing different amine-boranes with differing reducing ability (ammonia borane (AB), dimethylamine borane (DMAB), and triethylamine borane (TMAB)) was found to have a profound effect on the particle size and the size distribution. Usage of AB as the reducing agent provided the smallest possible size with best size distribution. Employment of TMAB also afforded similar results; however, when DMAB was used as the reducing agent it resulted in larger sized nanoparticles that are polydisperse too. In the AB mediated reduction, BNH(x) polymer generated in situ acts as a capping agent whereas, the complexing amine of the other amine-boranes (DMAB and TMAB) play the same role. Employing the solid state route described herein, monometallic Au, Ag, Cu, Pd, and Ir and bimetallic CuAg and CuAu alloy nanoparticles of <10 nm were successfully prepared. Nucleation and growth processes that control the size and the size distribution of the resulting nanoparticles have been elucidated in these systems.

Environmental Monitoring, Water Quality - Total Maximum Daily Load (TMDL)

Data.gov (United States)

NSGIC Education | GIS Inventory — The Clean Water Act Section 303(d) establishes the Total Maximum Daily Load (TMDL) program. The purpose of the TMDL program is to identify sources of pollution and...

Site Specific Metal Criteria Developed Using Kentucky Division of Water Procedures

International Nuclear Information System (INIS)

Kszos, L.A.; Phipps, T.L.

1999-01-01

Alternative limits for Cu, Ni, Pb, and Zn were developed for treated wastewater from four outfalls at a Gaseous Diffusion Plant. Guidance from the Kentucky Division of Water (KDOW) was used to (1) estimate the toxicity of the effluents using water fleas (Ceriodaphnia dubia) and fathead minnow (Pimephales promelas) larvae; (2) determine total recoverable and dissolved concentrations of Cu, Pb, Ni, and Zn ; (3) calculate ratios of dissolved metal (DM) to total recoverable metal (TRM); and (4) assess chemical characteristics of the effluents. Three effluent samples from each outfall were collected during each of six test periods; thus, a total of 18 samples from each outfall were evaluated for toxicity, DM and TRM. Subsamples were analyzed for alkalinity, hardness, pH, conductivity, and total suspended solids. Short-term (6 or 7 d), static renewal toxicity tests were conducted according to EPA methodology. Ceriodaphnia reproduction was reduced in one test of effluent from Outfall A , and effluent from Outfall B was acutely toxic to both test species during one test. However, the toxicity was not related to the metals present in the effluents. Of the 18 samples from each outfall, more than 65% of the metal concentrations were estimated quantities. With the exception of two total recoverable Cu values in Outfall C, all metal concentrations were below the permit limits and the federal water quality criteria. Ranges of TR for all outfalls were: Cd, ,0.1-0.4 microg/L; Cr,1.07-3.93 microg/L; Cu, 1.59-7.24 microg/L; Pb, 39%. Thus, the alternative, calculated total recoverable metal concentration provides the discharger with a ''cushion'' for meeting permit limits

Integrating Transition Metals into Nanomaterials: Strategies and Applications

KAUST Repository

Fhayli, Karim

2016-01-01

Transition metals complexes have been involved in various catalytic, biomedical and industrial applications, but only lately they have been associated with nanomaterials to produce innovative and well-defined new hybrid systems. The introduction of transition metals into nanomaterials is important to bear the advantages of metals to nanoscale and also to raise the stability of nanomaterials. In this dissertation, we study two approaches of associating transition metals into nanomaterials. The first approach is via spontaneous self-organization based assembly of small molecule amphiphiles and bulky hydrophilic polymers to produce organic-inorganic hybrid materials that have nanoscale features and can be precisely controlled depending on the experimental conditions used. These hybrid materials can successfully act as templates to design new porous material with interesting architecture. The second approach studied is via electroless reduction of transition metals on the surface of nanocarbons (nanotubes and nanodiamonds) without using any reducing agents or catalysts. The synthesis of these systems is highly efficient and facile resulting in stable and mechanically robust new materials with promising applications in catalysis.

Integrating Transition Metals into Nanomaterials: Strategies and Applications

KAUST Repository

Fhayli, Karim

2016-04-14

Transition metals complexes have been involved in various catalytic, biomedical and industrial applications, but only lately they have been associated with nanomaterials to produce innovative and well-defined new hybrid systems. The introduction of transition metals into nanomaterials is important to bear the advantages of metals to nanoscale and also to raise the stability of nanomaterials. In this dissertation, we study two approaches of associating transition metals into nanomaterials. The first approach is via spontaneous self-organization based assembly of small molecule amphiphiles and bulky hydrophilic polymers to produce organic-inorganic hybrid materials that have nanoscale features and can be precisely controlled depending on the experimental conditions used. These hybrid materials can successfully act as templates to design new porous material with interesting architecture. The second approach studied is via electroless reduction of transition metals on the surface of nanocarbons (nanotubes and nanodiamonds) without using any reducing agents or catalysts. The synthesis of these systems is highly efficient and facile resulting in stable and mechanically robust new materials with promising applications in catalysis.

Repeated phytoextraction of four metal-contaminated soils using the cadmium/zinc hyperaccumulator Sedum plumbizincicola

International Nuclear Information System (INIS)

Li, Zhu; Wu, Longhua; Hu, Pengjie; Luo, Yongming; Zhang, Hao; Christie, Peter

2014-01-01

A cadmium/zinc hyperaccumulator extracted metals from four contaminated soils over three years in a glasshouse experiment. Changes in plant metal uptake and soil total (aqua regia-extractable) and available metals were investigated. Plant Cd concentrations in a high-Cd acid soil and plant Zn concentrations in two acid soils decreased during repeated phytoextraction and were predicted by soil available metal concentrations. However, on repeated phytoextraction, plant Cd concentrations remained constant in lightly Cd-polluted acid soils, as did plant Cd and Zn in alkaline soils, although soil available metal concentrations decreased markedly. After phytoextraction acid soils showed much higher total metal removal efficiencies, indicating possible suitability of phytoextraction for acid soils. However, DGT-testing, which takes soil metal re-supply into consideration, showed substantial removal of available metal and distinct decreases in metal supply capacity in alkaline soils after phytoextraction, suggesting that a strategy based on lowering the bioavailable contaminant might be feasible. - Highlights: • Plant shoot Cd decreased in high-Cd acid soil and also plant Zn did in two acid soils. • Plant shoot Cd remained constant in low-Cd acid soil and also plant Zn did in alkaline soils. • Acidic soils showed much higher total metal removal efficiency than the alkaline soils. - Acid soil has high total metal phytoremediation efficiency while a strategy based on stripping of the bioavailable contaminant might be feasible for alkaline soil phytoremediation

Total petroleum hydrocarbons and heavy metals in the surface sediments of Bohai Bay, China: long-term variations in pollution status and adverse biological risk.

Science.gov (United States)

Zhou, Ran; Qin, Xuebo; Peng, Shitao; Deng, Shihuai

2014-06-15

Surface sediments collected from 2001 to 2011 were analyzed for total petroleum hydrocarbons (TPH) and five heavy metals. The sediment concentration ranges of TPH, Zn, Cu, Pb, Cd and Hg were 6.3-535 μg/g, 58-332 μg/g, 7.2-63 μg/g, 4.3-138 μg/g, 0-0.98μg/g, and 0.10-0.68 μg/g, respectively. These results met the highest marine sediment quality standards in China, indicating that the sediment was fairly clean. However, based on the effects range-median (ERM) quotient method, the calculated values for all of the sampling sites were higher than 0.10, suggesting that there was a potential adverse biological risk in Bohai Bay. According to the calculated results, the biological risk decreased from 2001 to 2007 and increased afterwards. High-risk sites were mainly distributed along the coast. This study suggests that anthropogenic influences might be responsible for the potential risk of adverse biological effects from TPH and heavy metals in Bohai Bay. Copyright © 2014 Elsevier Ltd. All rights reserved.

Heavy metals in surface sediments of the Jialu River, China: Their relations to environmental factors

Energy Technology Data Exchange (ETDEWEB)

Fu, Jie [State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing 210093 (China); Environmental Engineering Program, Department of Civil Engineering, Auburn University, Auburn, AL 36849 (United States); Zhao, Changpo [State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing 210093 (China); Luo, Yupeng [Department of Mathematics and Statistics, Auburn University, Auburn, AL 36849 (United States); Liu, Chunsheng, E-mail: liuchunshengidid@126.com [College of Fisheries, Huazhong Agricultural University, Wuhan 430070 (China); Kyzas, George Z. [Laboratory of General and Inorganic Chemical Technology, Department of Chemistry, Aristotle University of Thessaloniki, Thessaloniki 54124 (Greece); Luo, Yin [State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing 210093 (China); Zhao, Dongye [Environmental Engineering Program, Department of Civil Engineering, Auburn University, Auburn, AL 36849 (United States); An, Shuqing [State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing 210093 (China); Zhu, Hailiang, E-mail: zhuhl@nju.edu.cn [State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing 210093 (China)

2014-04-01

Highlights: • Zhengzhou City had major effect on the pollution of the Jialu River. • TN, OP, TP and COD{sub Mn} in water drove heavy metals to deposit in sediments. • B-IBI was sensitive to the adverse effect of heavy metals in sediments. - Abstract: This work investigated heavy metal pollution in surface sediments of the Jialu River, China. Sediment samples were collected at 19 sites along the river in connection with field surveys and the total concentrations were determined using atomic fluorescence spectrometer and inductively coupled plasma optical emission spectrometer. Sediment samples with higher metal concentrations were collected from the upper reach of the river, while sediments in the middle and lower reaches had relatively lower metal concentrations. Multivariate techniques including Pearson correlation, hierarchical cluster and principal components analysis were used to evaluate the metal sources. The ecological risk associated with the heavy metals in sediments was rated as moderate based on the assessments using methods of consensus-based Sediment Quality Guidelines, Potential Ecological Risk Index and Geo-accumulation Index. The relations between heavy metals and various environmental factors (i.e., chemical properties of sediments, water quality indices and aquatic organism indices) were also studied. Nitrate nitrogen, total nitrogen, and total polycyclic aromatic hydrocarbons concentrations in sediments showed a co-release behavior with heavy metals. Ammonia nitrogen, total nitrogen, orthophosphate, total phosphate and permanganate index in water were found to be related to metal sedimentation. Heavy metals in sediments posed a potential impact on the benthos community.

Heavy metals in surface sediments of the Jialu River, China: Their relations to environmental factors

International Nuclear Information System (INIS)

Fu, Jie; Zhao, Changpo; Luo, Yupeng; Liu, Chunsheng; Kyzas, George Z.; Luo, Yin; Zhao, Dongye; An, Shuqing; Zhu, Hailiang

2014-01-01

Highlights: • Zhengzhou City had major effect on the pollution of the Jialu River. • TN, OP, TP and COD Mn in water drove heavy metals to deposit in sediments. • B-IBI was sensitive to the adverse effect of heavy metals in sediments. - Abstract: This work investigated heavy metal pollution in surface sediments of the Jialu River, China. Sediment samples were collected at 19 sites along the river in connection with field surveys and the total concentrations were determined using atomic fluorescence spectrometer and inductively coupled plasma optical emission spectrometer. Sediment samples with higher metal concentrations were collected from the upper reach of the river, while sediments in the middle and lower reaches had relatively lower metal concentrations. Multivariate techniques including Pearson correlation, hierarchical cluster and principal components analysis were used to evaluate the metal sources. The ecological risk associated with the heavy metals in sediments was rated as moderate based on the assessments using methods of consensus-based Sediment Quality Guidelines, Potential Ecological Risk Index and Geo-accumulation Index. The relations between heavy metals and various environmental factors (i.e., chemical properties of sediments, water quality indices and aquatic organism indices) were also studied. Nitrate nitrogen, total nitrogen, and total polycyclic aromatic hydrocarbons concentrations in sediments showed a co-release behavior with heavy metals. Ammonia nitrogen, total nitrogen, orthophosphate, total phosphate and permanganate index in water were found to be related to metal sedimentation. Heavy metals in sediments posed a potential impact on the benthos community

Bioaccessibility of micron-sized powder particles of molybdenum metal, iron metal, molybdenum oxides and ferromolybdenum--Importance of surface oxides.

Science.gov (United States)

Mörsdorf, Alexander; Odnevall Wallinder, Inger; Hedberg, Yolanda

2015-08-01

The European chemical framework REACH requires that hazards and risks posed by chemicals, including alloys and metals, that are manufactured, imported or used in different products (substances or articles) are identified and proven safe for humans and the environment. Metals and alloys need hence to be investigated on their extent of released metals (bioaccessibility) in biologically relevant environments. Read-across from available studies may be used for similar materials. This study investigates the release of molybdenum and iron from powder particles of molybdenum metal (Mo), a ferromolybdenum alloy (FeMo), an iron metal powder (Fe), MoO2, and MoO3 in different synthetic body fluids of pH ranging from 1.5 to 7.4 and of different composition. Spectroscopic tools and cyclic voltammetry have been employed to characterize surface oxides, microscopy, light scattering and nitrogen absorption for particle characterization, and atomic absorption spectroscopy to quantify released amounts of metals. The release of molybdenum from the Mo powder generally increased with pH and was influenced by the fluid composition. The mixed iron and molybdenum surface oxide of the FeMo powder acted as a barrier both at acidic and weakly alkaline conditions. These findings underline the importance of the surface oxide characteristics for the bioaccessibility of metal alloys. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.

Diagnostic value of lipids, total antioxidants, and trace metals in ...

African Journals Online (AJOL)

2012-05-28

May 28, 2012 ... PSA assay could reduce the associated cost of care and give timely attention to prostate cancer patients ... Prostate cancer (Pca) and benign prostate hyperplasia ..... triglyceride and total cholesterol values in benign prostatic.

Metal-Containing Polystyrene Beads as Standards for Mass Cytometry.

Science.gov (United States)

Abdelrahman, Ahmed I; Ornatsky, Olga; Bandura, Dmitry; Baranov, Vladimir; Kinach, Robert; Dai, Sheng; Thickett, Stuart C; Tanner, Scott; Winnik, Mitchell A

2010-01-01

We examine the suitability of metal-containing polystyrene beads for the calibration of a mass cytometer instrument, a single particle analyser based on an inductively coupled plasma ion source and a time of flight mass spectrometer. These metal-containing beads are also verified for their use as internal standards for this instrument. These beads were synthesized by multiple-stage dispersion polymerization with acrylic acid as a comonomer. Acrylic acid acts as a ligand to anchor the metal ions within the interior of the beads. Mass cytometry enabled the bead-by-bead measurement of the metal-content and determination of the metal-content distribution. Beads synthesized by dispersion polymerization that involved three stages were shown to have narrower bead-to-bead variation in their lanthanide content than beads synthesized by 2-stage dispersion polymerization. The beads exhibited insignificant release of their lanthanide content to aqueous solutions of different pHs over a period of six months. When mixed with KG1a or U937 cell lines, metal-containing polymer beads were shown not to affect the mass cytometry response to the metal content of element-tagged antibodies specifically attached to these cells.

40 CFR 63.7507 - What are the health-based compliance alternatives for the hydrogen chloride (HCl) and total...

Science.gov (United States)

2010-07-01

... alternatives for the hydrogen chloride (HCl) and total selected metals (TSM) standards? 63.7507 Section 63.7507... Standards for Hazardous Air Pollutants for Industrial, Commercial, and Institutional Boilers and Process... the hydrogen chloride (HCl) and total selected metals (TSM) standards? (a) As an alternative to the...

Three-dimensional metal-intercalated covalent organic frameworks for near-ambient energy storage

Science.gov (United States)

Gao, Fei; Ding, Zijing; Meng, Sheng

2013-01-01

A new form of nanoporous material, metal intercalated covalent organic framework (MCOF) is proposed and its energy storage property revealed. Employing density functional and thermodynamical analysis, we find that stable, chemically active, porous materials could form by stacking covalent organic framework (COF) layers with metals as a gluing agent. Metal acts as active sites, while its aggregation is suppressed by a binding energy significantly larger than the corresponding cohesive energy of bulk metals. Two important parameters, metal binding and metal-metal separation, are tuned by selecting suitable building blocks and linkers when constructing COF layers. Systematic searches among a variety of elements and organic molecules identify Ca-intercalated COF with diphenylethyne units as optimal material for H2 storage, reaching a striking gravimetric density ~ 5 wt% at near-ambient conditions (300 K, 20 bar), in comparison to < 0.1 wt% for bare COF-1 under the same condition. PMID:23698018

heavy metals and cyanide distribution in the villages surrounding ...

African Journals Online (AJOL)

detection limit) were higher in the wells closest to the Tailing Storage Facility ... Key Words: Heavy metals pollution, Total cyanide, ground water pollution and ..... cyanide, heavy metals and probably other hazardous substances, leakage of.

Near-unity transparency of a continuous metal film via cooperative effects of double plasmonic arrays

International Nuclear Information System (INIS)

Liu Zhengqi; Liu Guiqiang; Liu Xiaoshan; Huang Kuan; Chen Yuanhao; Fu Guolan; Zhou Haiqing

2013-01-01

Metal structures with high optical transparency and conductivity are of great importance for practical applications in optoelectronic devices. Here we investigate the transparency response of a continuous metal film sandwiched by double plasmonic nanoparticle arrays. The upper nanoparticle array shows efficient light trapping of the incident field, acting as a light input coupler, and the lower nanoparticle array shows a light release gate opening at the other side, acting as the light output coupler. The strong near-field light–matter interactions of the nano-scale separated plasmonic nanoparticles, the excitation of surface plasmon waves of the metal film, and their cooperative coupling effects result in broadband scattering cancellation and near-unity transparency (up to 96%) in the optical regime. The transparency response in such a structure can be efficiently modified by varying the gap distance of adjacent nanoparticles, dielectric environments, and the distance between the plasmonic array and the metal film. This motif may provide a new alternative approach to obtain transparent and highly conducting metal structures with potential applications in transparent conductors, plasmonic filters, and highly integrated light input and output components. (paper)

25 CFR 700.33 - Act (The Act).

Science.gov (United States)

2010-04-01

... 25 Indians 2 2010-04-01 2010-04-01 false Act (The Act). 700.33 Section 700.33 Indians THE OFFICE OF NAVAJO AND HOPI INDIAN RELOCATION COMMISSION OPERATIONS AND RELOCATION PROCEDURES General Policies and Instructions Definitions § 700.33 Act (The Act). (a) The Act. The Act is Pub. L. 93-531, (88 Stat...

Ferroelastic ceramic-reinforced metal matrix composites

OpenAIRE

2006-01-01

Composite materials comprising ferroelastic ceramic particulates dispersed in a metal matrix are capable of vibration damping. When the ferroelastic ceramic particulates are subjected to stress, such as the cyclic stress experienced during vibration of the material, internal stresses in the ceramic cause the material to deform via twinning, domain rotation or domain motion thereby dissipating the vibrational energy. The ferroelastic ceramic particulates may also act as reinforcements to impro...

The current state of bearing surfaces in total hip replacement.

Science.gov (United States)

Rajpura, A; Kendoff, D; Board, T N

2014-02-01

We reviewed the literature on the currently available choices of bearing surface in total hip replacement (THR). We present a detailed description of the properties of articulating surfaces review the understanding of the advantages and disadvantages of existing bearing couples. Recent technological developments in the field of polyethylene and ceramics have altered the risk of fracture and the rate of wear, although the use of metal-on-metal bearings has largely fallen out of favour, owing to concerns about reactions to metal debris. As expected, all bearing surface combinations have advantages and disadvantages. A patient-based approach is recommended, balancing the risks of different options against an individual's functional demands.

Some stars are totally metal: a new mechanism driving dust across star-forming clouds, and consequences for planets, stars, and galaxies

Energy Technology Data Exchange (ETDEWEB)

Hopkins, Philip F., E-mail: phopkins@caltech.edu [TAPIR, Mailcode 350-17, California Institute of Technology, Pasadena, CA 91125 (United States)

2014-12-10

Dust grains in neutral gas behave as aerodynamic particles, so they can develop large local density fluctuations entirely independent of gas density fluctuations. Specifically, gas turbulence can drive order-of-magnitude 'resonant' fluctuations in the dust density on scales where the gas stopping/drag timescale is comparable to the turbulent eddy turnover time. Here we show that for large grains (size ≳ 0.1 μm, containing most grain mass) in sufficiently large molecular clouds (radii ≳ 1-10 pc, masses ≳ 10{sup 4} M {sub ☉}), this scale becomes larger than the characteristic sizes of prestellar cores (the sonic length), so large fluctuations in the dust-to-gas ratio are imprinted on cores. As a result, star clusters and protostellar disks formed in large clouds should exhibit significant abundance spreads in the elements preferentially found in large grains (C, O). This naturally predicts populations of carbon-enhanced stars, certain highly unusual stellar populations observed in nearby open clusters, and may explain the 'UV upturn' in early-type galaxies. It will also dramatically change planet formation in the resulting protostellar disks, by preferentially 'seeding' disks with an enhancement in large carbonaceous or silicate grains. The relevant threshold for this behavior scales simply with cloud densities and temperatures, making straightforward predictions for clusters in starbursts and high-redshift galaxies. Because of the selective sorting by size, this process is not necessarily visible in extinction mapping. We also predict the shape of the abundance distribution—when these fluctuations occur, a small fraction of the cores may actually be seeded with abundances Z ∼ 100 (Z) such that they are almost 'totally metal' (Z ∼ 1)! Assuming the cores collapse, these totally metal stars would be rare (1 in ∼10{sup 4} in clusters where this occurs), but represent a fundamentally new stellar evolution channel.

Unanticipated potential cancer risk near metal recycling facilities

International Nuclear Information System (INIS)

Raun, Loren; Pepple, Karl; Hoyt, Daniel; Richner, Donald; Blanco, Arturo; Li, Jiao

2013-01-01

Metal recycling is an important growing industry. Prior to this study, area sources consisting of metal recycling facilities fell in a category of limited regulatory scrutiny because of assumed low levels of annual emissions. Initiating with community complaints of nuisance from smoke, dust and odor, the Houston Department of Health and Human Services (HDHHS) began a monitoring program outside metal recycler facilities and found metal particulates in outdoor ambient air at levels which could pose a carcinogenic human health risk. In a study of five similar metal recycler facilities which used a torch cutting process, air downwind and outside the facility was sampled for eight hours between 6 and 10 times each over 18 months using a mobile laboratory. Ten background locations were also sampled. Iron, manganese, copper, chromium, nickel, lead, cobalt, cadmium and mercury were detected downwind of the metal recyclers at frequencies ranging from 100% of the time for iron to 2% of the time for mercury. Of these metals, chromium, nickel, lead, cobalt, cadmium and mercury were not detected in any sample in the background. Two pairs of samples were analyzed for total chromium and hexavalent chromium to establish a ratio of the fraction of hexavalent chromium in total chromium. This fraction was used to estimate hexavalent chromium at all locations. The carcinogenic risk posed to a residential receptor from metal particulate matter concentrations in the ambient air attributed to the metal recyclers was estimated from each of the five facilities in an effort to rank the importance of this source and inform the need for further investigation. The total risk from these area sources ranged from an increased cancer risk of 1 in 1,000,000 to 6 in 10,000 using the 95th upper confidence limit of the mean of the carcinogenic metal particulate matter concentration, assuming the point of the exposure is the sample location for a residential receptor after accounting for wind direction

Unanticipated potential cancer risk near metal recycling facilities

Energy Technology Data Exchange (ETDEWEB)

Raun, Loren, E-mail: raun@rice.edu [Department of Statistics, MS 138, Rice University, P.O. Box 1892, Houston, TX 77251-1892 (United States); Pepple, Karl, E-mail: pepple.karl@epa.gov [State and Local Programs Group, Air Quality Policy Division, Office of Air Quality Planning and Standards, Policy, Analysis, and Communications Staff, Mail Drop C404-03, U.S. EPA, Research Triangle Park, NC 27711 (United States); Hoyt, Daniel, E-mail: hoyt.daniel@epa.gov [Air Surveillance Section, US EPA, Region 6, 6EN-AS, 1445 Ross Avenue, Dallas, TX 75202-2733 (United States); Richner, Donald, E-mail: Donald.Richner@houstontx.gov [Houston Department of Health and Human Services, Bureau of Pollution Control and Prevention, 7411 Park Place Blvd., Houston, TX 77087 (United States); Blanco, Arturo, E-mail: arturo.blanco@houstontx.gov [Pollution Control and Prevention, Environmental Health Division, Houston Department of Health and Human Services, 7411 Park Place Blvd., Houston, TX 77087 (United States); Li, Jiao, E-mail: jiao.li@rice.edu [Wiess School of Natural Science, Rice University, 6100 Main St., Houston, TX 77005 (United States)

2013-07-15

Metal recycling is an important growing industry. Prior to this study, area sources consisting of metal recycling facilities fell in a category of limited regulatory scrutiny because of assumed low levels of annual emissions. Initiating with community complaints of nuisance from smoke, dust and odor, the Houston Department of Health and Human Services (HDHHS) began a monitoring program outside metal recycler facilities and found metal particulates in outdoor ambient air at levels which could pose a carcinogenic human health risk. In a study of five similar metal recycler facilities which used a torch cutting process, air downwind and outside the facility was sampled for eight hours between 6 and 10 times each over 18 months using a mobile laboratory. Ten background locations were also sampled. Iron, manganese, copper, chromium, nickel, lead, cobalt, cadmium and mercury were detected downwind of the metal recyclers at frequencies ranging from 100% of the time for iron to 2% of the time for mercury. Of these metals, chromium, nickel, lead, cobalt, cadmium and mercury were not detected in any sample in the background. Two pairs of samples were analyzed for total chromium and hexavalent chromium to establish a ratio of the fraction of hexavalent chromium in total chromium. This fraction was used to estimate hexavalent chromium at all locations. The carcinogenic risk posed to a residential receptor from metal particulate matter concentrations in the ambient air attributed to the metal recyclers was estimated from each of the five facilities in an effort to rank the importance of this source and inform the need for further investigation. The total risk from these area sources ranged from an increased cancer risk of 1 in 1,000,000 to 6 in 10,000 using the 95th upper confidence limit of the mean of the carcinogenic metal particulate matter concentration, assuming the point of the exposure is the sample location for a residential receptor after accounting for wind direction

Behavior as a sentry of metal toxicity

Energy Technology Data Exchange (ETDEWEB)

Weiss, B.

1978-01-01

Many of the toxic properties of metals are expressed as behavioral aberrations. Some of these arise from direct actions on the central nervous system. Others arise from primary events elsewhere, but still influence behavior. Toxicity may be expressed either as objectively measurable phenomena, such as ataxia, or as subjective complaints, such as depression. In neither instance is clinical medicine equipped to provide assessments of subtle, early indices of toxicity. Reviewers of visual disturbances, paresthesia, and mental retardation exemplify the potential contribution of psychology to the toxicology of metals. Behavior and nervous system functions act as sensitive mirrors of metal toxicity. Sensitivity is the prime aim in environmental health assessments. Early detection of adverse effects, before they progress to irreversibility, underlies the strategy for optimal health protection. Some of the toxic actions of metals originate in direct nervous system dysfunction. Others may reflect disturbances of systems less directly linked to behavior than the central nervous system. But behavior, because it expresses the integrated functioning of the organism, can indicate flaws in states and processes outside the nervous system.

Indicator minerals as guides to base metal sulphide mineralisation ...

Indian Academy of Sciences (India)

Zn-bearing minerals that act as indicator minerals for base metal sulphide mineralization from the Proterozoic Betul Belt,central India with special emphasis on their genetic significance have been discussed.Sulphide mineralisation is hosted by the felsic volcanic rocks and has similarities with volcanic-hosted massive ...

Considering bioavailability in the remediation of heavy metal contaminated sites

Directory of Open Access Journals (Sweden)

Leita L.

2013-04-01

Full Text Available Many years of research have demonstrated that instead of the total concentration of metals in soil, bioavailability is the key to understand the environmental risk derived by metals, since adverse effects are related only to the biologically available forms of these elements. The knowledge of bioavailability can decrease the uncertainties in evaluating exposure in human and ecological risk assessment. At the same time, the efficiency of remediation treatments could be greatly influenced by availability of the contaminants. Consideration of the bioavailability processes at contaminated sites could be useful in site-specific risk assessment: the fraction of mobile metals, instead of total content should be provided as estimates of metal exposure. Moreover, knowledge of the chemical forms of heavy metals in soils is a critical component in the evaluation of applicability of different remediation technologies such as phytoremdiation or soil washing.

Transfer of metallic debris from the metal surface of an acetabular cup to artificial femoral heads by scraping: comparison between alumina and cobalt-chrome heads.

Science.gov (United States)

Chang, Chong Bum; Yoo, Jeong Joon; Song, Won Seok; Kim, Deug Joong; Koo, Kyung-Hoi; Kim, Hee Joong

2008-04-01

We aimed to investigate the transfer of metal to both ceramic (alumina) and metal (cobalt-chrome) heads that were scraped by a titanium alloy surface under different load conditions. The ceramic and metal heads for total hip arthroplasties were scraped by an acetabular metal shell under various loads using a creep tester. Microstructural changes in the scraped area were visualized with a scanning electron microscope, and chemical element changes were assessed using an energy dispersive X-ray spectrometry. Changes in the roughness of the scraped surface were evaluated by a three-dimensional surface profiling system. Metal transfer to the ceramic and metal heads began to be detectable at a 10 kg load, which could be exerted by one-handed force. The surface roughness values significantly increased with increasing test loads in both heads. When the contact force increased, scratching of the head surface occurred in addition to the transfer of metal. The results documented that metallic debris was transferred from the titanium alloy acetabular shell to both ceramic and metal heads by minor scraping. This study suggests that the greatest possible effort should be made to protect femoral heads, regardless of material, from contact with metallic surfaces during total hip arthroplasty.

Industrial recovered-materials-utilization targets for the metals and metal-products industry

Energy Technology Data Exchange (ETDEWEB)

None

1980-03-01

The National Energy Conservation Policy Act of 1978 directs DOE to set targets for increased utilization of energy-saving recovered materials for certain industries. These targets are to be established at levels representing the maximum feasible increase in utilization of recovered materials that can be achieved progressively by January 1, 1987 and is consistent with technical and economic factors. A benefit to be derived from the increased use of recoverable materials is in energy savings, as state in the Act. Therefore, emhasis on different industries in the metals sector has been related to their energy consumption. The ferrous industry (iron and steel, ferrour foundries and ferralloys), as defined here, accounts for approximately 3%, and all others for the remaining 3%. Energy consumed in the lead and zinc segments is less than 1% each. Emphasis is placed on the ferrous scrap users, followed by the aluminum and copper industries. A bibliography with 209 citations is included.

Metal-assisted etch combined with regularizing etch

Energy Technology Data Exchange (ETDEWEB)

Yim, Joanne; Miller, Jeff; Jura, Michael; Black, Marcie R.; Forziati, Joanne; Murphy, Brian; Magliozzi, Lauren

2018-03-06

In an aspect of the disclosure, a process for forming nanostructuring on a silicon-containing substrate is provided. The process comprises (a) performing metal-assisted chemical etching on the substrate, (b) performing a clean, including partial or total removal of the metal used to assist the chemical etch, and (c) performing an isotropic or substantially isotropic chemical etch subsequently to the metal-assisted chemical etch of step (a). In an alternative aspect of the disclosure, the process comprises (a) performing metal-assisted chemical etching on the substrate, (b) cleaning the substrate, including removal of some or all of the assisting metal, and (c) performing a chemical etch which results in regularized openings in the silicon substrate.

Immunological Responses to Total Hip Arthroplasty.

Science.gov (United States)

Man, Kenny; Jiang, Lin-Hua; Foster, Richard; Yang, Xuebin B

2017-08-01

The use of total hip arthroplasties (THA) has been continuously rising to meet the demands of the increasingly ageing population. To date, this procedure has been highly successful in relieving pain and restoring the functionality of patients' joints, and has significantly improved their quality of life. However, these implants are expected to eventually fail after 15-25 years in situ due to slow progressive inflammatory responses at the bone-implant interface. Such inflammatory responses are primarily mediated by immune cells such as macrophages, triggered by implant wear particles. As a result, aseptic loosening is the main cause for revision surgery over the mid and long-term and is responsible for more than 70% of hip revisions. In some patients with a metal-on-metal (MoM) implant, metallic implant wear particles can give rise to metal sensitivity. Therefore, engineering biomaterials, which are immunologically inert or support the healing process, require an in-depth understanding of the host inflammatory and wound-healing response to implanted materials. This review discusses the immunological response initiated by biomaterials extensively used in THA, ultra-high-molecular-weight polyethylene (UHMWPE), cobalt chromium (CoCr), and alumina ceramics. The biological responses of these biomaterials in bulk and particulate forms are also discussed. In conclusion, the immunological responses to bulk and particulate biomaterials vary greatly depending on the implant material types, the size of particulate and its volume, and where the response to bulk forms of differing biomaterials are relatively acute and similar, while wear particles can initiate a variety of responses such as osteolysis, metal sensitivity, and so on.

Packaging a liquid metal ESD with micro-scale Mercury droplet.

Energy Technology Data Exchange (ETDEWEB)

Barnard, Casey Anderson

2011-08-01

A liquid metal ESD is being developed to provide electrical switching at different acceleration levels. The metal will act as both proof mass and electric contact. Mercury is chosen to comply with operation parameters. There are many challenges surrounding the deposition and containment of micro scale mercury droplets. Novel methods of micro liquid transfer are developed to deliver controllable amounts of mercury to the appropriate channels in volumes under 1 uL. Issues of hermetic sealing and avoidance of mercury contamination are also addressed.

EFFICIENCY OF METAL SCRAP SEPARATION IN EDDY CURRENT SEPARATOR

Directory of Open Access Journals (Sweden)

Gordan Bedeković

2008-11-01

Full Text Available Eddy-current separation is most often method used for the recovery of non-ferrous metals (Al, Cu, Zn, Pb from solid wastes and also for separating non-ferrous metals from each other. The feed material comes to rotary drum and magnetic field by belt conveyer. The changing magnetic field induce eddy currents in conductive (metallic particles. Because interaction between this currents and the magnetic field electrodynamic forces will act on conductive particles. Therefore the trajectories of conductive particles will be different from the trajectories of the non-conductive ones. Separation is a result of the combined actions of several forces (electrodynamic, gravitational and frictional. The paper presents results of aluminium recovery from mixture of metallic particles in eddy current separator. Testing were conducted under field condition. Results shows that is possible achieve recovery of 99 % and concentrate quality of 89 % of aluminium (the paper is published in Croatian.

Evaluation of the onset of failure under mechanical and thermal stresses on luting agent for metal-ceramic and metal crowns by finite element analysis

Directory of Open Access Journals (Sweden)

Hema Agnihotri

2010-01-01

Full Text Available Long-term clinical failures of cemented prosthesis depend, to a large extent, on the integrity of the luting agent. The causative factors that lead to microfracture and, hence, failure of the luting agents are the stresses acting inside the oral cavity. Therefore, the present study was designed to develop an understanding of the relationship between stresses in the tooth and the failure potential of the luting agent. Two-dimensional finite element stress analysis was performed on the mandibular second premolar. The behavior of zinc-phosphate and glass-ionomer were studied under different crowns (metal-ceramic and metal crown and loading conditions (mechanical force of 450 N acting vertically over the occlusal surface, thermal loads of 60° and 0°C. It was observed from the study that failure threshold of the luting agent was influenced both by the elastic modulus of the luting agent and by the type of the crown.

Some metals in aboveground biomass of Scots pine in Lithuania

DEFF Research Database (Denmark)

Varnagiryte-Kabašinskiene, Iveta; Armolaitis, Kestutis; Stupak, Inge

2014-01-01

with stemwood and living branches. However, metal export with aboveground biomass represented relatively small proportion of metals in mineral sandy soil. The annual inputs of Fe and Zn with atmospheric deposition were over 10 times higher than the mean annual removals with total aboveground biomass....... The content of metals in forest biomass fuel ash was relatively small to compare with their total removals. The findings of this study have an important implications for future practice, i.e. the recommended maximum forest biomass fuel ash dose for the compensating fertilising could be increased with respect...... to balanced output - input in Lithuania....

Metal ion-dependent DNAzymes and their applications as biosensors.

Science.gov (United States)

Lan, Tian; Lu, Yi

2012-01-01

Long considered to serve solely as the genetic information carrier, DNA has been shown in 1994 to be able to act as DNA catalysts capable of catalyzing a trans-esterification reaction similar to the action of ribozymes and protein enzymes. Although not yet found in nature, numerous DNAzymes have been isolated through in vitro selection for catalyzing many different types of reactions in the presence of different metal ions and thus become a new class of metalloenzymes. What remains unclear is how DNA can carry out catalysis with simpler building blocks and fewer functional groups than ribozymes and protein enzymes and how DNA can bind metal ions specifically to perform these functions. In the past two decades, many biochemical and biophysical studies have been carried out on DNAzymes, especially RNA-cleaving DNAzymes. Important insights have been gained regarding their metal-dependent activity, global folding, metal binding sites, and catalytic mechanisms for these DNAzymes. Because of their high metal ion selectivity, one of the most important practical applications for DNAzymes is metal ion detection, resulting in highly sensitive and selective fluorescent, colorimetric, and electrochemical sensors for a wide range of metal ions such as Pb(2+), UO2 2 +,[Formula: see text] including paramagnetic metal ions such as Cu(2+). This chapter summarizes recent progresses in in vitro selection of metal ion-selective DNAzymes, their biochemical and biophysical studies and sensing applications.

Liquid-metal dip seal with pneumatic spring

International Nuclear Information System (INIS)

Poindexter, A.M.

1977-01-01

An improved liquid-metal dip seal for sealing the annulus between rotating plugs in the reactor vessel head of a liquid-metal fast-breeder nuclear reactor has two legs of differing widths communicating under a seal blade; the wide leg is also in communication with cover gas of the reactor and the narrow leg is also in communication with an isolated plug annulus above the seal. The annulus contains inert gas which acts as a pneumatic spring. Upon increasing cover gas pressure which depresses the level in the wide leg and greatly increases the level in the narrow leg, the pneumatic spring is compressed, and resists further level changes, thus preventing radioactive cover gas from bubbling through the seal

Description of Latvian Metal Production and Processing Enterprises' Air Emissions

OpenAIRE

Pubule, J; Zahare, D; Blumberga, D

2010-01-01

The metal production and processing sector in Latvia has acquired a stable position in the national economy. Smelting of ferrous and nonferrous metals, production of metalware, galvanisation, etc. are developed in Latvia. The metal production and processing sector has an impact on air quality due to polluting substances which are released in the air from metal treatment processes. Therefore it is necessary to determine the total volume of emissions produced by the metal production and process...

Silica Supported Platinum Catalysts for Total Oxidation of the Polyaromatic Hydrocarbon Naphthalene: An Investigation of Metal Loading and Calcination Temperature

Directory of Open Access Journals (Sweden)

David R. Sellick

2015-04-01

Full Text Available A range of catalysts comprising of platinum supported on silica, prepared by an impregnation method, have been studied for the total oxidation of naphthalene, which is a representative Polycyclic Aromatic Hydrocarbon. The influence of platinum loading and calcination temperature on oxidation activity was evaluated. Increasing the platinum loading up to 2.5 wt.% increased the catalyst activity, whilst a 5.0 wt.% catalyst was slightly less active. The catalyst containing the optimum 2.5 wt.% loading was most active after calcination in air at 550 °C. Characterisation by carbon monoxide chemisorption and X-ray photoelectron spectroscopy showed that low platinum dispersion to form large platinum particles, in combination with platinum in metallic and oxidised states was important for high catalyst activity. Catalyst performance improved after initial use in repeat cycles, whilst there was slight deactivation after prolonged time-on-stream.

PLANNING OF IMPLANTO‐PROSTHETIC STRUCTURES IN TOTAL EDENTATION ACCORDING TO BIOMECHANICAL CRITERIA

Directory of Open Access Journals (Sweden)

N. VASILE

2013-07-01

Full Text Available Scope of the study: Analysis of the biomechanical aspects of the implanto‐prosthetic structures for planning the treatment in cases of total edentation.Materials and method: The study was performed in the Clinics of Prosthetics and Oral Implantology, Military Emergency Hospital of Sibiu, on a group of mandibularly totally edentated patients. Planning of the implanto‐pros‐ thetic treatment had in view the peculiarities of total man‐ dibular edentation and observance of the biomechanical principles. Selection of the type of occlusion restoration considered the presence of parafunctions and the nature of the antagonistic arch. Special attention was paid to the direction and intensity of the forces acting in the region of the future prosthetic work. When bruxism was manifested, its preimplantary removal was compulsory.Results and discussion: In fixed prosthetic restaurati‐ ons applied on implants, distribuition of forces obviously depend on the quality of osteo‐acceptance, as well, and also on the elasticity degree of the prosthetic work. In the case of mobilized prosthetic restorations supported on implants, rigidization of implants from the anterior region of the mandible may be obtained by means of a bar. In decreasing order of their elasticity, the materials employed are: acrylate, composites, noble and seminoble alloys, other metals, ceramics. Ceramics confers maximum stability to implants, yet without redeeming the forces. For amortizing the forces and for a progressive charging of the implants, it is recommended that the first (temporary prosthetic restorations should be made of either acrylate or compo‐ sites.Conclusions. Observance of the occlusological princi‐ ples in cases of occlusal reconstruction represents the determining element which assures the osteo‐acceptance of implants and the integrity of prosthetic restaurations.

Validation of Transfer Functions Predicting Cd and Pb Free Metal Ion Activity in Soil Solution as a Function of Soil Characteristics and Reactive Metal Content

NARCIS (Netherlands)

Pampura, T.; Groenenberg, J.E.; Lofts, S.; Priputina, I.

2007-01-01

According to recent insight, the toxicity of metals in soils is better related to the free metal ion (FMI) activity in the soil solution than to the total metal concentration in soil. However, the determination of FMI activities in soil solution is a difficult and time-consuming task. An alternative

Influence of Heavy Metal Stress on Antioxidant Status and DNA Damage in Urtica dioica

Directory of Open Access Journals (Sweden)

Darinka Gjorgieva

2013-01-01

Full Text Available Heavy metals have the potential to interact and induce several stress responses in the plants; thus, effects of heavy metal stress on DNA damages and total antioxidants level in Urtica dioica leaves and stems were investigated. The samples are sampled from areas with different metal exposition. Metal content was analyzed by Inductively Coupled Plasma-Atomic Emission Spectrometer (ICP-AES, for total antioxidants level assessment the Ferric-Reducing Antioxidant Power (FRAP assay was used, and genomic DNA isolation from frozen plant samples was performed to obtain DNA fingerprints of investigated plant. It was found that heavy metal contents in stems generally changed synchronously with those in leaves of the plant, and extraneous metals led to imbalance of mineral nutrient elements. DNA damages were investigated by Random Amplified Polymorphic DNA (RAPD technique, and the results demonstrated that the samples exposed to metals yielded a large number of new fragments (total 12 in comparison with the control sample. This study showed that DNA stability is highly affected by metal pollution which was identified by RAPD markers. Results suggested that heavy metal stress influences antioxidant status and also induces DNA damages in U. dioica which may help to understand the mechanisms of metals genotoxicity.

Influence of heavy metal stress on antioxidant status and DNA damage in Urtica dioica.

Science.gov (United States)

Gjorgieva, Darinka; Kadifkova Panovska, Tatjana; Ruskovska, Tatjana; Bačeva, Katerina; Stafilov, Trajče

2013-01-01

Heavy metals have the potential to interact and induce several stress responses in the plants; thus, effects of heavy metal stress on DNA damages and total antioxidants level in Urtica dioica leaves and stems were investigated. The samples are sampled from areas with different metal exposition. Metal content was analyzed by Inductively Coupled Plasma-Atomic Emission Spectrometer (ICP-AES), for total antioxidants level assessment the Ferric-Reducing Antioxidant Power (FRAP) assay was used, and genomic DNA isolation from frozen plant samples was performed to obtain DNA fingerprints of investigated plant. It was found that heavy metal contents in stems generally changed synchronously with those in leaves of the plant, and extraneous metals led to imbalance of mineral nutrient elements. DNA damages were investigated by Random Amplified Polymorphic DNA (RAPD) technique, and the results demonstrated that the samples exposed to metals yielded a large number of new fragments (total 12) in comparison with the control sample. This study showed that DNA stability is highly affected by metal pollution which was identified by RAPD markers. Results suggested that heavy metal stress influences antioxidant status and also induces DNA damages in U. dioica which may help to understand the mechanisms of metals genotoxicity.

Handheld colorimeter for determination of heavy metal concentrations

Science.gov (United States)

López Ruiz, N.; Ariza, M.; Martínez Olmos, A.; Vukovic, J.; Palma, A. J.; Capitan-Vallvey, L. F.

2011-08-01

A portable instrument that measures heavy metal concentration from a colorimetric sensor array is presented. The use of eight sensing membranes, placed on a plastic support, allows to obtain the hue component of the HSV colour space of each one in order to determinate the concentration of metals present in a solution. The developed microcontroller-based system captures, in an ambient light environment, an image of the sensor array using an integrated micro-camera and shows the picture in a touch micro-LCD screen which acts as user interface. After image-processing of the regions of interest selected by the user, colour and concentration information are displayed on the screen.

Handheld colorimeter for determination of heavy metal concentrations

International Nuclear Information System (INIS)

Lopez Ruiz, N; Martinez Olmos, A; Palma, A J; Ariza, M; Capitan-Vallvey, L F; Vukovic, J

2011-01-01

A portable instrument that measures heavy metal concentration from a colorimetric sensor array is presented. The use of eight sensing membranes, placed on a plastic support, allows to obtain the hue component of the HSV colour space of each one in order to determinate the concentration of metals present in a solution. The developed microcontroller-based system captures, in an ambient light environment, an image of the sensor array using an integrated micro-camera and shows the picture in a touch micro-LCD screen which acts as user interface. After image-processing of the regions of interest selected by the user, colour and concentration information are displayed on the screen.

Handheld colorimeter for determination of heavy metal concentrations

Energy Technology Data Exchange (ETDEWEB)

Lopez Ruiz, N; Martinez Olmos, A; Palma, A J [ECSens ETSIIT, Departamento de Electronica, Universidad de Granada. C/ Periodista Daniel Saucedo s/n 18071 Granada (Spain); Ariza, M; Capitan-Vallvey, L F [Department of Analytical Chemistry. Faculty of Sciences. University of Granada, E-18071 Granada (Spain); Vukovic, J, E-mail: nurilr@ugr.es [Department of Analytics and Control of Medicines, Faculty of Pharmacy and Biochemistry, University of Zagreb, A. Kovacica 1,HR-10000 Zagreb (Croatia)

2011-08-17

A portable instrument that measures heavy metal concentration from a colorimetric sensor array is presented. The use of eight sensing membranes, placed on a plastic support, allows to obtain the hue component of the HSV colour space of each one in order to determinate the concentration of metals present in a solution. The developed microcontroller-based system captures, in an ambient light environment, an image of the sensor array using an integrated micro-camera and shows the picture in a touch micro-LCD screen which acts as user interface. After image-processing of the regions of interest selected by the user, colour and concentration information are displayed on the screen.

A multisite interaction expansion of the total energy in metals

International Nuclear Information System (INIS)

Sowa, E.C.; Gonis, A.

1994-01-01

The local-density approximation provides a proper setting for the decomposition of total energy into many-body (many-atom) contributions. Multiple scattering theory in turn provides a convenient framework for carrying out this process. We illustrate this concept with calculations on a linear chain of atoms in bulk copper

Slow waves in microchannel metal waveguides and application to particle acceleration

OpenAIRE

L. C. Steinhauer; W. D. Kimura

2003-01-01

Conventional metal-wall waveguides support waveguide modes with phase velocities exceeding the speed of light. However, for infrared frequencies and guide dimensions of a fraction of a millimeter, one of the waveguide modes can have a phase velocity equal to or less than the speed of light. Such a metal microchannel then acts as a slow-wave structure. Furthermore, if it is a transverse magnetic mode, the electric field has a component along the direction of propagation. Therefore, a strong ex...

Method for improved decomposition of metal nitrate solutions

Science.gov (United States)

Haas, Paul A.; Stines, William B.

1983-10-11

A method for co-conversion of aqueous solutions of one or more heavy metal nitrates wherein thermal decomposition within a temperature range of about 300.degree. to 800.degree. C. is carried out in the presence of about 50 to 500% molar concentration of ammonium nitrate to total metal.

Corrosion processes of physical vapor deposition-coated metallic implants.

Science.gov (United States)

Antunes, Renato Altobelli; de Oliveira, Mara Cristina Lopes

2009-01-01

Protecting metallic implants from the harsh environment of physiological fluids is essential to guaranteeing successful long-term use in a patient's body. Chemical degradation may lead to the failure of an implant device in two different ways. First, metal ions may cause inflammatory reactions in the tissues surrounding the implant and, in extreme cases, these reactions may inflict acute pain on the patient and lead to loosening of the device. Therefore, increasing wear strength is beneficial to the performance of the metallic implant. Second, localized corrosion processes contribute to the nucleation of fatigue cracks, and corrosion fatigue is the main reason for the mechanical failure of metallic implants. Common biomedical alloys such as stainless steel, cobalt-chrome alloys, and titanium alloys are prone to at least one of these problems. Vapor-deposited hard coatings act directly to improve corrosion, wear, and fatigue resistances of metallic materials. The effectiveness of the corrosion protection is strongly related to the structure of the physical vapor deposition layer. The aim of this paper is to present a comprehensive review of the correlation between the structure of physical vapor deposition layers and the corrosion properties of metallic implants.

Bioavailability of Sediment-bound Heavy Metals on the East African ...

African Journals Online (AJOL)

Abstract—Currently, environmental risk assessment of metals is based on comparisons of toxicity thresholds against environmental exposure levels measured as total ..... Transition Metals in the Amazon and. Yukon rivers. Geol Soc Am Bull.

Y-12 old salvage yard scrap metal characterization study

International Nuclear Information System (INIS)

Anderson, L.M.; Melton, S.G.; Shaw, S.S.

1993-11-01

The purpose of the Y-12 Old Salvage Yard scrap metal Characterization Study is to make conservative estimates of the quantities of total uranium and the wt % 235 U contained in scrap metal. The original project scope included estimates of thorium, but due to the insignificant quantities found in the yards, thorium was excluded from further analysis. Metal in three of the four Y-12 scrap metal yards were characterized. The scrap metal yard east of the PIDAS fence is managed by the Environmental Restoration Program and therefore was not included in this study. For all Y-12 Plant scrap metal shipments, Waste Transportation, Storage, and Disposal (WTSD) personnel must complete a Request for Authorization to Ship Nuclear Materials, UCN-16409, which requires the grams of total uranium, the wt % 235 U, and the grams of 235 U contained in the shipment. This information is necessary to ensure compliance with Department of Transportation regulations, as well as to ensure that the receiving facility is adhering to its operating license. This characterization study was designed to provide a technical basis for determining these necessary radioactive quantities

Hazard and risk assessment of human exposure to toxic metals using in vitro digestion assay

Directory of Open Access Journals (Sweden)

Hani A. Alhadrami

2016-10-01

Full Text Available Clean-up targets for toxic metals require that the site be “fit for purpose”. This means that targets are set with respect to defined receptors that reflect intended land-use. In this study, the likely threat of human exposure to toxic metals has been evaluated by simulating the human digestion process in vitro. The effects of key attributes (i.e. sample fraction size, pH, Kd and total metal concentrations on the bioavailability of Cu and Ni were also investigated. Total metal concentration was the key explanatory factor for Cu and Ni bioavailability. A comparative ranking of metal concentrations in the context of tolerable daily intakes for Cu and Ni confirmed that the pH has the greatest impact on metals bioavailability. Rapid screening of key attributes and total toxic metal doses can reveal the relative hazard imposed on human, and this approach should be considered when defining threshold values for human protection.

The influence of nitrilotriacetate on heavy metal uptake of lettuce and ryegrass

Energy Technology Data Exchange (ETDEWEB)

Kulli, B.; Balmer, M.; Krebs, R.; Lothenbach, B.; Geiger, G.; Schulin, R.

1999-12-01

Metal uptake and removal from the soil by plants may be a useful measure to remediate contaminated soils. These processes can be enhanced by adding metal chelators to soil. The authors investigated the effect of nitrolotriacetate (NTA) and urea on the uptake of Cd, Cu, and Zn by lettuce (Lactuca sativa L. ev. Orion) and Italian ryegrass (Lolium perenne L. ev. Bastion) in pot experiments. Nitric acid-extractable heavy metal concentrations in the contaminated soil were 2 mg Cd, 530 mg Cu, and 700 mg Zn/kg. Three NTA treatments were compared with two urea treatments, and a control. Nitrilotriacetate and urea increased the NaNO{sub 3}-extractable soil concentrations of the three metals. At the highest NTA dose, metal concentrations in the aboveground plant biomass was 4 to 24 times greater than in the control plants. While NTA increased plant metal concentrations, it reduced plant matter production. At lower doses, this effect was small. At the highest NTA dose, plant growth was almost completely inhibited. Severe visual symptoms indicated metal toxicity as the likely cause. The urea treatments generally increased the plant matter production. Total metal uptake was in general larger at the lowest or at the intermediate NTA dose than at the highest doses. Little additional total metal uptake was achieved with NTA treatments than with urea. Compared with the controls, neither NTA nor urea enhanced total uptake under the given conditions by more than threefold.

COMPARISON OF DIFFERENT EXTRACTION METHODS REPRESENTING AVAILABLE AND TOTAL CONCENTRATIONS OF Cd, Cu, Fe, Mn and Zn IN SOIL

Directory of Open Access Journals (Sweden)

Vladimir Ivezić

2013-06-01

Full Text Available Various extraction methods are used to predict plant uptake of trace metals. Most commonly it is total concentration that is used for risk assessment and evaluation of trace metal availability. However, recent studies showed that total concentration is a poor indicator of availability while concentrations in soil solution show good correlation with plant uptake. Present study was conducted on magricultural soils with low levels of trace metals where 45 soil samples were collected from different soil types. The main objective was to compare four different extraction methods and examine how total and reactive (EDTA trace metal concentrations correlate ,with soil solution concentration (in this study determined by water extraction. The samples were analyzed by four extraction methods: strong acid extraction (ultra-pure HNO3 extraction and aqua regia, weak acid extraction by EDTA and the most available fraction, fraction in soil solution, were represented by water extraction (weakest extractant. Five elements were investigated (Cd, Cu, Fe, Mn and Zn. Water extraction significantly correlated with EDTA extraction for Cu, Fe and Mn, while total extraction (HNO3 extraction and aqua regia correlated significantly with water extraction only for Cu. No correlation between water extraction and total extraction confirmed poor role of total concentration as an indicator of availability. EDTA extraction can be used to represent reactive pool of trace metals in soil but it should be also taken with caution when using it to describe available fraction.

Metals transport in the Sacramento River, California, 1996-1997; Volume 2: Interpretation of metal loads

Science.gov (United States)

Alpers, Charles N.; Antweiler, Ronald C.; Taylor, Howard E.; Dileanis, Peter D.; Domagalski, Joseph L.

2000-01-01

Metals transport in the Sacramento River, northern California, from July 1996 to June 1997 was evaluated in terms of metal loads from samples of water and suspended colloids that were collected on up to six occasions at 13 sites in the Sacramento River Basin. Four of the sampling periods (July, September, and November 1996; and May-June 1997) took place during relatively low-flow conditions and two sampling periods (December 1996 and January 1997) took place during high-flow and flooding conditions, respectively. This study focused primarily on loads of cadmium, copper, lead, and zinc, with secondary emphasis on loads of aluminum, iron, and mercury.Trace metals in acid mine drainage from abandoned and inactive base-metal mines, in the East and West Shasta mining districts, enter the Sacramento River system in predominantly dissolved form into both Shasta Lake and Keswick Reservoir. The proportion of trace metals that was dissolved (as opposed to colloidal) in samples collected at Shasta and Keswick dams decreased in the order zinc ≈ cadmium > copper > lead. At four sampling sites on the Sacramento River--71, 256, 360, and 412 kilometers downstream of Keswick Dam--trace-metal loads were predominantly colloidal during both high- and low-flow conditions. The proportion of total cadmium, copper, lead, and zinc loads transported to San Francisco Bay and the Sacramento-San Joaquin Delta estuary (referred to as the Bay-Delta) that is associated with mineralized areas was estimated by dividing loads at Keswick Dam by loads 412 kilometers downstream at Freeport and the Yolo Bypass. During moderately high flows in December 1996, mineralization-related total (dissolved + colloidal) trace-metal loads to the Bay-Delta (as a percentage of total loads measured downstream) were cadmium, 87 percent; copper, 35 percent; lead, 10 percent; and zinc, 51 percent. During flood conditions in January 1997 loads were cadmium, 22 percent; copper, 11 percent; lead, 2 percent; and zinc, 15

Lumbricus terrestris L. activity increases the availability of metals and their accumulation in maize and barley

International Nuclear Information System (INIS)

Ruiz, E.; Alonso-Azcarate, J.; Rodriguez, L.

2011-01-01

The effect of the earthworm Lumbricus terrestris L. on metal availability in two mining soils was assessed by means of chemical extraction methods and a pot experiment using crop plants. Results from single and sequential extractions showed that L. terrestris had a slight effect on metal fractionation in the studied soils: only metals bound to the soil organic matter were significantly increased in some cases. However, we found that L. terrestris significantly increased root, shoot and total Pb and Zn concentrations in maize and barley for the soil with the highest concentrations of total and available metals. Specifically, shoot Pb concentration was increased by a factor of 7.5 and 3.9 for maize and barley, respectively, while shoot Zn concentration was increased by a factor of 3.7 and 1.7 for maize and barley, respectively. Our results demonstrated that earthworm activity increases the bioavailability of metals in soils. - Research highlights: → Lumbricus terrestris L. activity increases the bioavailability of metals in soils. → Earthworm activity can significantly increase total, shoot and root metal concentrations for crop plants. → Both bioassays and chemical extraction methods are necessary for assessing the bioavailability of metals in contaminated soils. - Lumbricus terrestris L. activity increases the bioavailability of metals in soils and total, shoot and root metal concentrations for maize and barley.

Lumbricus terrestris L. activity increases the availability of metals and their accumulation in maize and barley

Energy Technology Data Exchange (ETDEWEB)

Ruiz, E. [Department of Chemical Engineering, School of Civil Engineering, University of Castilla-La Mancha, Avenida Camilo Jose Cela, s/n, 13071 Ciudad Real (Spain); Alonso-Azcarate, J. [Department of Physical Chemistry, Faculty of Environmental Sciences, University of Castilla-La Mancha, Avenida Carlos III, s/n, 45071 Toledo (Spain); Rodriguez, L., E-mail: Luis.Rromero@uclm.es [Department of Chemical Engineering, School of Civil Engineering, University of Castilla-La Mancha, Avenida Camilo Jose Cela, s/n, 13071 Ciudad Real (Spain)

2011-03-15

The effect of the earthworm Lumbricus terrestris L. on metal availability in two mining soils was assessed by means of chemical extraction methods and a pot experiment using crop plants. Results from single and sequential extractions showed that L. terrestris had a slight effect on metal fractionation in the studied soils: only metals bound to the soil organic matter were significantly increased in some cases. However, we found that L. terrestris significantly increased root, shoot and total Pb and Zn concentrations in maize and barley for the soil with the highest concentrations of total and available metals. Specifically, shoot Pb concentration was increased by a factor of 7.5 and 3.9 for maize and barley, respectively, while shoot Zn concentration was increased by a factor of 3.7 and 1.7 for maize and barley, respectively. Our results demonstrated that earthworm activity increases the bioavailability of metals in soils. - Research highlights: > Lumbricus terrestris L. activity increases the bioavailability of metals in soils. > Earthworm activity can significantly increase total, shoot and root metal concentrations for crop plants. > Both bioassays and chemical extraction methods are necessary for assessing the bioavailability of metals in contaminated soils. - Lumbricus terrestris L. activity increases the bioavailability of metals in soils and total, shoot and root metal concentrations for maize and barley.

Assessment of metal retention in newly constructed highway embankments.

Science.gov (United States)

Werkenthin, Moritz; Kluge, Björn; Wessolek, Gerd

2016-12-01

Newly constructed embankments should provide both a specific bearing capacity to enable trafficability in emergency cases and a sufficient pollutant retention capacity to protect the groundwater. A number of lysimeters were installed along the A115 highway to determine total and dissolved metal concentrations in road runoff and in the soil solution of newly constructed embankments. Dissolved concentrations in soil solution of the embankments did not exceed the trigger values of the German legislation. Depending on the metal, total concentrations in soil solution were more than twice as high as dissolved concentrations. The high infiltration rates lead to increased groundwater recharge beneath the embankments (up to 4100 mm a -1 ). Although metal concentrations were not problematic from the legislators' point of view, the elevated infiltration rates beside the road facilitated the transfer of high metal loads into deeper soil layers and potentially into the groundwater as well.

Understanding interaction of curcumin and metal ions on electrode surfaces using EDXRF

Science.gov (United States)

Joseph, Daisy; Kumar, K. Krishna; Narayanan, S. Sriman

2018-04-01

A chemically modified electrode was developed for determination of metal ions (Cd, Pb, Zn, Co, Hg). The modifier used for the study was Curcumin. Curcumin acts as a complexing agent at the surface of the electrode for preconcentration of metal ions from electrolyte to electrode surface and stripped back to electrolyte during analysis. EDXRF was used to analyze these electrodes and it was concluded that the PCR modified electrode favored effective chelation for lead and mercury.

New process for weld metal reliability

International Nuclear Information System (INIS)

Hebel, A.G.

1985-01-01

The industry-wide nature of weld cracking alerts one to the possibility that there is a fundamental law being overlooked. And in overlooking this law, industry is unable to counteract it. That law mandates that restraint during welding causes internal stress; internal stress causes weld metal to crack. Component restraint during welding, according to the welding standard, is the major cause of weld metal failures. When the metal working industry accepts this fact and begins to counter the effects of restraint, the number of weld failures experienced fall dramatically. Bonal Technologies, inc., of Detroit, has developed the first consistently effective non-thermal process to relieve stress caused by restraint during welding. Bonal's patented Mets-Lax sub-resonant stress relief acts as a restraint neutralizer when used during welding. Meta-Lax weld conditioning produces a finer more uniform weld grain structure. A finer, more uniform grain structure is a clear metallurgical indication of improved mechanical weld properties. Other benefits like less internal stress, and less warpage are also achieved

Bad metal behaviour in the new Hg-rich amalgam KHg{sub 6} with polar metallic bonding

Energy Technology Data Exchange (ETDEWEB)

Tambornino, Frank; Hoch, Constantin, E-mail: constantin.hoch@cup.uni-muenchen.de

2015-01-05

Highlights: • The novel Hg-rich amalgam KHg{sub 6} was synthesised by electrocrystallisation. • The structure was investigated by single crystal and powder diffraction. • Thermal decomposition, electric resistance and magnetic susceptibiliy were examined. • Band structure, total and partial density of states and Bader charges were calculated. • Bad metal behaviour results from ionic, metallic and covalent bonding contributions. - Abstract: The new mercury-rich amalgam KHg{sub 6} crystallises with the BaHg{sub 6} structure type (orthorhombic, space group Pnma (No. 62), a = 13.394(9) Å, b = 5.270(3) Å, c = 10.463 Å). It was prepared by electrolysis of a solution of KI in N,N′-Dimethylformamide at 343 K at a reactive Hg cathode. The structure of KHg{sub 6} shows motifs of ionic packing, covalent Hg cluster formation and metallic properties. KHg{sub 6} decomposes peritectically at 443 K. The combination of alkali metals with a noble metal with moderate electron affinity results in the formation of polar metal–metal bonding with considerable but incomplete electron transfer from the electropositive to the electronegative sublattice, resulting in typical “bad metal behaviour”, illustrated by resistance and susceptibility measurements and quantum theoretical calculations.

Wear particles and osteolysis in patients with total wrist arthroplasty

DEFF Research Database (Denmark)

Boeckstyns, Michel E H; Toxværd, Anders; Bansal, Manjula

2014-01-01

PURPOSE: To determine whether the amount of polyethylene debris in the interphase tissue between prosthesis and bone in patients with total wrist arthroplasty correlated with the degree of periprosthetic osteolysis (PPO); and to investigate the occurrence of metal particles in the periprosthetic...... tissue, the level of chrome and cobalt ions in the blood, and the possible role of infectious or rheumatoid activity in the development of PPO. METHODS: Biopsies were taken from the implant-bone interphase in 13 consecutive patients with total wrist arthroplasty and with at least 3 years' follow......-up. Serial annual radiographs were performed prospectively for the evaluation of PPO. We collected blood samples for white blood cell count, C-reactive protein, and metallic ion level. RESULTS: A radiolucent zone of greater than 2 mm was observed juxta-articular to the radial component in 4 patients...

TRANSITION METAL TRANSPORT IN PLANTS AND ASSOCIATED ENDOSYMBIONTS: ARBUSCULAR MYCORRHIZAL FUNGI AND RHIZOBIA

Directory of Open Access Journals (Sweden)

Manuel González-Guerrero

2016-07-01

Full Text Available Transition metals such as iron, copper, zinc, or molybdenum, are essential nutrients for plants. These elements are involved in almost every biological process, including photosynthesis, tolerance to biotic and abiotic stress, or symbiotic nitrogen fixation. However, plants often grow in soils with limiting metallic oligonutrient bioavailability. Consequently, to ensure the proper metal levels, plants have developed a complex metal uptake and distribution system, that not only involves the plant itself, but also its associated microorganisms. These microorganisms can simply increase metal solubility in soils and making them more accessible to the host plant, as well as induce the plant metal deficiency response, or deliver directly transition elements to cortical cells. Other, instead of providing metals can act as metal sinks, such as endosymbiotic rhizobia in legume nodules that requires relatively large amounts to carry out nitrogen fixation. In this review, we propose to do an overview of metal transport mechanisms in the plant-microbe system, emphasizing the role of arbuscular mycorrhizal fungi and endosymbiotic rhizobia.

Effect of multiple metal resistant bacteria from contaminated lake sediments on metal accumulation and plant growth

International Nuclear Information System (INIS)

Li, Kefeng; Ramakrishna, Wusirika

2011-01-01

Naturally occurring bacteria play an important role in bioremediation of heavy metal pollutants in soil and wastewater. This study identified high levels of resistance to zinc, cesium, lead, arsenate and mercury in eight copper resistant Pseudomonas strains previously isolated from Torch Lake sediment. These strains showed variable susceptibility to different antibiotics. Furthermore, these metal resistant strains were capable of bioaccumulation of multiple metals and solubilization of copper. Bacterial strains TLC 3-3.5-1 and TLC 6-6.5-1 showed high bioaccumulation ability of Zn (up to 15.9 mg/g dry cell) and Pb (80.7 mg/g dry cell), respectively. All the strains produced plant growth promoting indole-3-acetic acid (IAA), iron chelating siderophore and solubilized mineral phosphate and metals. The effect of bacterial inoculation on plant growth and copper uptake by maize (Zea mays) and sunflower (Helianthus annuus) was investigated using one of the isolates (Pseudomonas sp. TLC 6-6.5-4) with higher IAA production and phosphate and metal soubilization, which resulted in a significant increase in copper accumulation in maize and sunflower, and an increase in the total biomass of maize. The multiple metal-resistant bacterial isolates characterized in our study have potential applications for remediation of metal contaminated soils in combination with plants and metal contaminated water.

Effect of multiple metal resistant bacteria from contaminated lake sediments on metal accumulation and plant growth

Energy Technology Data Exchange (ETDEWEB)

Li, Kefeng [Department of Biological Sciences, Michigan Technological University, 1400 Townsend Drive, Houghton, MI 49931 (United States); Ramakrishna, Wusirika, E-mail: wusirika@mtu.edu [Department of Biological Sciences, Michigan Technological University, 1400 Townsend Drive, Houghton, MI 49931 (United States)

2011-05-15

Naturally occurring bacteria play an important role in bioremediation of heavy metal pollutants in soil and wastewater. This study identified high levels of resistance to zinc, cesium, lead, arsenate and mercury in eight copper resistant Pseudomonas strains previously isolated from Torch Lake sediment. These strains showed variable susceptibility to different antibiotics. Furthermore, these metal resistant strains were capable of bioaccumulation of multiple metals and solubilization of copper. Bacterial strains TLC 3-3.5-1 and TLC 6-6.5-1 showed high bioaccumulation ability of Zn (up to 15.9 mg/g dry cell) and Pb (80.7 mg/g dry cell), respectively. All the strains produced plant growth promoting indole-3-acetic acid (IAA), iron chelating siderophore and solubilized mineral phosphate and metals. The effect of bacterial inoculation on plant growth and copper uptake by maize (Zea mays) and sunflower (Helianthus annuus) was investigated using one of the isolates (Pseudomonas sp. TLC 6-6.5-4) with higher IAA production and phosphate and metal soubilization, which resulted in a significant increase in copper accumulation in maize and sunflower, and an increase in the total biomass of maize. The multiple metal-resistant bacterial isolates characterized in our study have potential applications for remediation of metal contaminated soils in combination with plants and metal contaminated water.

Ecotoxicological assessment of metal-polluted urban soils using bioassays with three soil invertebrates.

Science.gov (United States)

Santorufo, Lucia; Van Gestel, Cornelis A M; Maisto, Giulia

2012-07-01

This study aimed at assessing the quality of urban soils by integrating chemical and ecotoxicological approaches. Soils from five sites in downtown Naples, Italy, were sampled and characterized for physical-chemical properties and total and water-extractable metal concentrations. Bioassays with Eisenia andrei, Enchytraeus crypticus and Folsomia candida were performed to assess toxicity of the soils, using survival, reproduction and growth as the endpoints. Metal bioaccumulation in the animals was also measured. The properties and metal concentrations of the soils strongly differed. Metal bioaccumulation was related with total metal concentrations in soil and was highest in E. crypticus, which was more sensitive than E. andrei and F. candida. Responses of the three species to the investigated soils seemed due to both metal contamination and soil properties. Copyright © 2012 Elsevier Ltd. All rights reserved.

Barrier Coatings for Refractory Metals and Superalloys

Energy Technology Data Exchange (ETDEWEB)

SM Sabol; BT Randall; JD Edington; CJ Larkin; BJ Close

2006-02-23

In the closed working fluid loop of the proposed Prometheus space nuclear power plant (SNPP), there is the potential for reaction of core and plant structural materials with gas phase impurities and gas phase transport of interstitial elements between superalloy and refractory metal alloy components during service. Primary concerns are surface oxidation, interstitial embrittlement of refractory metals and decarburization of superalloys. In parallel with kinetic investigations, this letter evaluates the ability of potential coatings to prevent or impede communication between reactor and plant components. Key coating requirements are identified and current technology coating materials are reviewed relative to these requirements. Candidate coatings are identified for future evaluation based on current knowledge of design parameters and anticipated environment. Coatings were identified for superalloys and refractory metals to provide diffusion barriers to interstitial transport and act as reactive barriers to potential oxidation. Due to their high stability at low oxygen potential, alumina formers are most promising for oxidation protection given the anticipated coolant gas chemistry. A sublayer of iridium is recommended to provide inherent diffusion resistance to interstitials. Based on specific base metal selection, a thin film substrate--coating interdiffusion barrier layer may be necessary to meet mission life.

Barrier Coatings for Refractory Metals and Superalloys

International Nuclear Information System (INIS)

SM Sabol; BT Randall; JD Edington; CJ Larkin; BJ Close

2006-01-01

In the closed working fluid loop of the proposed Prometheus space nuclear power plant (SNPP), there is the potential for reaction of core and plant structural materials with gas phase impurities and gas phase transport of interstitial elements between superalloy and refractory metal alloy components during service. Primary concerns are surface oxidation, interstitial embrittlement of refractory metals and decarburization of superalloys. In parallel with kinetic investigations, this letter evaluates the ability of potential coatings to prevent or impede communication between reactor and plant components. Key coating requirements are identified and current technology coating materials are reviewed relative to these requirements. Candidate coatings are identified for future evaluation based on current knowledge of design parameters and anticipated environment. Coatings were identified for superalloys and refractory metals to provide diffusion barriers to interstitial transport and act as reactive barriers to potential oxidation. Due to their high stability at low oxygen potential, alumina formers are most promising for oxidation protection given the anticipated coolant gas chemistry. A sublayer of iridium is recommended to provide inherent diffusion resistance to interstitials. Based on specific base metal selection, a thin film substrate--coating interdiffusion barrier layer may be necessary to meet mission life

Soil Heavy Metal Concentrations in Green Space of Mobarake Steel Complex

Directory of Open Access Journals (Sweden)

vahid Moradinasab

2017-01-01

Full Text Available Introduction: Water shortage in arid and semiarid regions of the world is a cause of serious concerns. The severe water scarcity urges the reuse of treated wastewater effluent and marginal water as a resource for irrigation. Mobarake Steel Complex has been using treated industrial wastewater for drip-irrigation of trees in about 1350 ha of its green space. However, wastewater may contain some amounts of toxic heavy metals, which create problems. Excessive accumulation of heavy metals in agricultural soils through wastewater irrigation may not only result in soil contamination, but also affect food quality and safety. Improper irrigation management, however, can lead to the loss of soil quality through such processes as contamination and salination. Soil quality implies its capacity to sustain biological productivity, maintain environmental quality, and enhance plants, human and animal health. Soil quality assessment is a tool that helps managers to evaluate short-term soil problems and appropriate management strategies for maintaining soil quality in the long time. Mobarakeh Steel Complex has been using treated wastewater for irrigation of green space to combat water shortage and prevent environmental pollution. This study was performed to assess the impact of short- middle, and long-term wastewater irrigation on soil heavy metal concentration in green space of Mobarake Steel complex. Materials and Methods: The impacts of wastewater irrigation on bioavailable and total heavy metal concentrations in the soils irrigated with treated wastewater for 2, 6 and 18 years as compared to those in soils irrigated with groundwater and un-irrigated soils. Soils were sampled from the wet bulb produced by under-tree sprinklers in three depths (0-20, 20-40 and 40-60 cm. Soil samples were air-dried, and crushed to pass through a 2-mm sieve. Plant-available metal concentrations were extracted from the soil with diethylenetriaminepentaacetic acid-CaCl2

Validation of the Brazilian version of the childhood asthma control test (c-ACT).

Science.gov (United States)

Oliveira, Suelen G; Sarria, Edgar E; Roncada, Cristian; Stein, Renato T; Pitrez, Paulo M; Mattiello, Rita

2016-04-01

Children's perception of their symptoms has proved reliable and relevant to disease management and should be considered when assessing their asthma control. The aim of the study is to validate the Brazilian Portuguese version of the Childhood Asthma Control Test (c-ACT) in children aged 4-11 years. This is a cross-sectional study in children diagnosed with asthma undergoing treatment in a pediatric pulmonology outpatient clinic in Porto Alegre, Brazil. The translation and linguistic adaptation of the instrument were performed in accordance with international recommendations for questionnaire validation. A total of 105 participants were included, aged 4-11 years. all correlations between the total score and items on the questionnaire were significant and obtained values of r ≥ 0.3, and c-ACT means showed statistically significant differences between the GINA categories (P ACT scores than those of uncontrolled asthma group (controlled 22.0 ± 2.9 vs. uncontrolled 16.3 ± 5.3 P ACT scores than those of uncontrolled asthma group (partially controlled 20.0 ± 4.0 vs. uncontrolled 16.3 ± 5.3 P = 0.03). Correlations between the c-ACT total score and spirometry and nitric oxide were poor (r = 0.020; P = 0.866 and r = 0.035; P = 0.753, respectively). Reliability: the α-C coefficient for the c-ACT total score was 0.677 (95%CI 0.573-0763). Sensitivity to change had an effect size of 0.8 and an intraclass correlation coefficient of 0.598. No floor or ceiling effects were observed. The Brazilian version of the Childhood Asthma Control Test proved to be valid and reliable in children aged 4-11 years. © 2015 Wiley Periodicals, Inc.

Tailoring of transition metal alkoxides via complexation for the synthesis of hybrid organic-inorganic sols and gels

International Nuclear Information System (INIS)

Sanchez, C.; In, M.; Toledano, P.; Griesmar, P.

1992-01-01

This paper reports that the chemical control of hydrolysis-condensation reactions of transition metal alkoxides can be performed through the modification of the transition metal coordination sphere by using strong complexing ligands (SCL). Complexing organic groups can be bonded to the transition metal oxide network in two different ways, as network modifiers or network formers. Different illustrations of the role of complexing ligands on Ti(IV) and Zr(IV) alkoxides are presented. As a network modifier, SCL act as termination agents for condensation reactions allowing a control of particle growth. The complexing ligands being located at the periphery of the oxo core open many opportunities for colloid surface protection. SCL carrying organofunctional groups which exhibit non linear optical (NLO) properties have also been used as probes to study sol-gel transformations. SCL functionalized with organic polymerizable functions act as network formers

Electric field-triggered metal-insulator transition resistive switching of bilayered multiphasic VOx

Science.gov (United States)

Won, Seokjae; Lee, Sang Yeon; Hwang, Jungyeon; Park, Jucheol; Seo, Hyungtak

2018-01-01

Electric field-triggered Mott transition of VO2 for next-generation memory devices with sharp and fast resistance-switching response is considered to be ideal but the formation of single-phase VO2 by common deposition techniques is very challenging. Here, VOx films with a VO2-dominant phase for a Mott transition-based metal-insulator transition (MIT) switching device were successfully fabricated by the combined process of RF magnetron sputtering of V metal and subsequent O2 annealing to form. By performing various material characterizations, including scanning transmission electron microscopy-electron energy loss spectroscopy, the film is determined to have a bilayer structure consisting of a VO2-rich bottom layer acting as the Mott transition switching layer and a V2O5/V2O3 mixed top layer acting as a control layer that suppresses any stray leakage current and improves cyclic performance. This bilayer structure enables excellent electric field-triggered Mott transition-based resistive switching of Pt-VOx-Pt metal-insulator-metal devices with a set/reset current ratio reaching 200, set/reset voltage of less than 2.5 V, and very stable DC cyclic switching upto 120 cycles with a great set/reset current and voltage distribution less than 5% of standard deviation at room temperature, which are specifications applicable for neuromorphic or memory device applications. [Figure not available: see fulltext.

Translocation of metals in pea plants grown on various amendment of electroplating industrial sludge.

Science.gov (United States)

Bose, Sutapa; Chandrayan, Sudarshana; Rai, Vivek; Bhattacharyya, A K; Ramanathan, A L

2008-07-01

A pot-culture experiment was conducted to observe the effects of acidic sludge addition to the soils on bioavailability and uptake of heavy metals in different parts of pea plant as well as its influence on the growth of that plant. It is observed from our result the abundances of total and bio-available heavy metals in sludge vary as follows: Fe>Mn>Cr>Ni>Cu>Pb>Zn>Cd and Fe>Ni>Mn>Cr>Cu>Zn>Pb>Cd. Sludge applications increased both the total metals, DTPA-extractable metals and total N in the soils. On the other hand lime application has decreased the bioavailability of heavy metals with no change in total N in sludge amended soils. Organic carbon showed positive correlation with all metals except Zn, Cr and Pb. CEC also showed a strong positive correlation (R(2)>0.7) with the low translocation efficiency of pea plants. The value of translocation factor from shoot to seed was found to be smaller than root to shoot of pea plants. Our study thus shows that pea plants were found to be well adapted to the soil amended with 10% sludge with 0.5% lime treatment, minimizing most of the all metal uptake in the shoot of that plant. So, on the basis of the present study, possible treatment may be recommended for the secure disposal of acidic electroplating sludge.

Fungal inoculation and elevated CO2 mediate growth of Lolium mutiforum and Phytolacca americana, metal uptake, and metal bioavailability in metal-contaminated soil: evidence from DGT measurement.

Science.gov (United States)

Song, Ningning; Wang, Fangli; Zhang, Changbo; Tang, Shirong; Guo, Junkang; Ju, Xuehai; Smith, Donald L

2013-01-01

Fungal inoculation and elevated CO2 may mediate plant growth and uptake of heavy metals, but little evidence from Diffusive Gradients in Thin-films (DGT) measurement has been obtained to characterize the process. Lolium mutiforum and Phytolacca americana were grown at ambient and elevated CO2 on naturally Cd and Pb contaminated soils inoculated with and without Trichoderma asperellum strain C3 or Penicillium chrysogenum strain D4, to investigate plant growth, metal uptake, and metal bioavailability responses. Fungal inoculation increased plant biomass and shoot/root Cd and Pb concentrations. Elevated CO2 significantly increased plants biomass, but decreased Cd and Pb concentrations in shoot/root to various extents, leading to a metal dilution phenomenon. Total Cd and Pb uptake by plants, and DGT-measured Cd and Pb concentrations in rhizosphere soils, were higher in all fungal inoculation and elevated CO2 treatments than control treatments, with the combined treatments having more influence than either treatment alone. Metal dilution phenomenon occurred because the increase in DGT-measured bioavailable metal pools in plant rhizosphere due to elevated CO2 was unable to match the increase in requirement for plant uptake of metals due to plant biomass increase.

Simulated effect of timing and Pt quantity injected on On-line NobleChem application on total fuel liftoff

International Nuclear Information System (INIS)

Pop, M.G.; Riddle, J.M.; Lamanna, L.S.; Gregorich, C.; Hoornik, A.

2015-01-01

Total liftoff is a measure of fuel performance and a risk indicator for fuel reliability. Fuel operability and license limits are directly related to the expected total lifetime liftoff. AREVA's continued commitment to zero fuel failure is expressed, among other efforts, in the continued development and improvement of its fuel cladding corrosion and crud risk assessment tools. The AREVA models used to assess and predict crud deposition on BWR cores over their lifespan have been refined by the development and incorporation of the PEZOG tool in response to the move in the industry to the On-Line NobleChem TM (OLNC) technology. PEZOG models the platinum-enhanced zirconium oxide growth of fuel cladding when exposed to platinum during operation. Depending on the local chemistry and radiation condition, noble metals act as catalysts for many reactions, including but not limited to hydrogen oxidation and oxygen reduction. OLNC's intention is to catalyze the hydrogen and oxygen recombination reaction for core internals protection. However, research has indicated that noble metals catalyze the oxygen reduction under the chemistry and radiation conditions as experienced in the pores of crud deposits, and hence, can increase the corrosion rate of zirconium alloy cladding. The developed PEZOG module calculates the oxide thickness as a function of platinum injection strategy. The stratified nature of oxide and crud layers formed on fuel cladding surfaces is reflected in the calculations as are the different platinum interaction in each of the layers. This paper presents examples of the evaluation of various aspects of the platinum injection strategies and their influence on the oxide growth enhancement as applied to conditions of a U.S. plant. (authors)

Colour interceptions, thermal stability and surface morphology of polyester metal complexes

International Nuclear Information System (INIS)

Zohdy, M.H.

2005-01-01

Chelating copolymers via grafting of acrylic acid (AAc) and acrylamide (AAm/AAc) comonomer mixture onto polyester micro fiber fabrics (PETMF) using gamma-radiation technique were prepared. The prepared graft chains (PETMF-g-AAc) and (PETMF-g-PAAc/PAAm) acted as chelating sites for some selected transition metal ions. The prepared graft copolymers and their metal complexes were characterized using thermogravimetric analysis (TGA), colour parameters and surface morphology measurements. The colour interception and strength measurements showed that the metal complexation is homogeneously distributed. The results showed that the thermal stability of PETMF was improved after graft copolymerization and metal complexes. Moreover, the degree of grafting enhanced the thermal stability values of the grafted and complexed copolymers up to 25% of magnitude, on the other hand the activation energy of the grafted-copolymer with acrylic acid increased up to 80%. The SEM observation gives further supports to the homogenous distribution of grafting and metal complexation

Amine promoted, metal enhanced degradation of Mirex under high temperature conditions

Energy Technology Data Exchange (ETDEWEB)

Jallad, Karim N. [American University of Sharjah, Department of Chemistry, P.O. Box 26666, Sharjah (United Arab Emirates)]. E-mail: kjallad@runbox.com; Lynn, Bert C. [University of Kentucky, Department of Chemistry, Lexington, KY 40506-055 (United States); Alley, Earl G. [Mississippi State University, Department of Chemistry, MS State, MS 39762 (United States)

2006-07-31

In this study, zero-valent metal dehalogenation of mirex was conducted with amine solvents at high temperatures. Mirex was treated with excess amine in sealed glass tube reactors under nitrogen. The amines used were n-butyl amine (l), ethyl amine (l), dimethyl amine (g), diethyl amine (l), triethyl amine (l), trimethyl amine (g) and ammonia (g). The metals used were copper, zinc, magnesium, aluminum and calcium. The most suitable amine solvent and metal were selected by running a series of reactions with different amines and different zero-valent metals, in order to optimize the conditions under which complete degradation of mirex takes place. These dehalogenation reactions illustrated the role of zero-valent metals as reductants, whereas the amine solvents acted as proton donors. In this study, we report that mirex was completely degraded with diethyl amine (l) in the presence of copper at 100 deg. C and the hydrogenated products accounted for more than 94 of the degraded mirex.

Solubility and diffusion of hydrogen in pure metals and alloys

International Nuclear Information System (INIS)

Wipf, H.

2001-01-01

Basic facts are presented of the absorption of hydrogen gas by metals and the diffusion of hydrogen in metals. Specifically considered are crystalline metals without defects and lattice disorder (pure metals), low hydrogen concentrations and the possibility of high hydrogen gas pressures. The first introductory topic is a short presentation of typical phase diagrams of metal hydrogen systems. Then, hydrogen absorption is discussed and shown to be decisively determined by the enthalpy of solution, in particular by its sign which specifies whether absorption is exothermic or endothermic. The formation of high-pressure hydrogen gas bubbles in a metal, which can lead to blistering, is addressed. It is demonstrated that bubble formation will, under realistic conditions, only occur in strongly endothermically hydrogen absorbing metals. The chief aspects of hydrogen diffusion in metals are discussed, especially the large size of the diffusion coefficient and its dependence on lattice structure. It is shown that forces can act on hydrogen in metals, causing a directed hydrogen flux. Such forces arise, for instance, in the presence of stress and temperature gradients and can result in local hydrogen accumulation with potential material failure effects. The final aspect discussed is hydrogen permeation, where the absorption behavior of the hydrogen is found to be in general more decisive on the permeation rate than the value of the diffusion coefficient. (orig.)

Toxic metals in children's toys and jewelry: coupling bioaccessibility with risk assessment.

Science.gov (United States)

Cui, Xin-Yi; Li, Shi-Wei; Zhang, Shu-Jun; Fan, Ying-Ying; Ma, Lena Q

2015-05-01

A total of 45 children's toys and jewelry were tested for total and bioaccessible metal concentrations. Total As, Cd, Sb, Cr, Ni, and Pb concentrations were 0.22-19, 0.01-139, 0.1-189, 0.06-846, 0.14-2894 and 0.08-860,000 mg kg(-1). Metallic products had the highest concentrations, with 3-7 out of 13 samples exceeding the European Union safety limit for Cd, Pb, Cr, or Ni. However, assessment based on hazard index >1 and bioaccessible metal showed different trends. Under saliva mobilization or gastric ingestion, 11 out of 45 samples showed HI >1 for As, Cd, Sb, Cr, or Ni. Pb with the highest total concentration showed HI toys and jewelry, and besides Pb and Cd, As, Ni, Cr, and Sb in children's products also deserve attention. Published by Elsevier Ltd.

Metal nanostructures: from clusters to nanocatalysis and sensors

Science.gov (United States)

Smirnov, B. M.

2017-12-01

The properties of metal clusters and nanostructures composed of them are reviewed. Various existing methods for the generation of intense beams of metal clusters and their subsequent conversion into nanostructures are compared. Processes of the flow of a buffer gas with active molecules through a nanostructure are analyzed as a basis of using nanostructures for catalytic applications. The propagation of an electric signal through a nanostructure is studied by analogy with a macroscopic metal. An analysis is given of how a nanostructure changes its resistance as active molecules attach to its surface and are converted into negative ions. These negative ions induce the formation of positively charged vacancies inside the metal conductor and attract the vacancies to together change the resistance of the metal nanostructure. The physical basis is considered for using metal clusters and nanostructures composed of them to create new materials in the form of a porous metal film on the surface of an object. The fundamentals of nanocatalysis are reviewed. Semiconductor conductometric sensors consisting of bound nanoscale grains or fibers acting as a conductor are compared with metal sensors conducting via a percolation cluster, a fractal fiber, or a bunch of interwoven nanofibers formed in superfluid helium. It is shown that sensors on the basis of metal nanostructures are characterized by a higher sensitivity than semiconductor ones, but are not selective. Measurements using metal sensors involve two stages, one of which measures to high precision the attachment rate of active molecules to the sensor conductor, and in the other one the surface of metal nanostructures is cleaned from the attached molecules using a gas discharge plasma (in particular, capillary discharge) with a subsequent chromatography analysis for products of cleaning.

Trace metal emissions from the Estonian oil shale fired power

DEFF Research Database (Denmark)

Aunela-Tapola, Leena A.; Frandsen, Flemming; Häsänen, Erkki K.

1998-01-01

Emission levels of selected trace metals from the Estonian oil shale fired power plant were studied. The plant is the largest single power plant in Estonia with an electricity production capacity of 1170 MWe (1995). Trace metals were sampled from the flue gases by a manual method incorporating...... in the flue gases of the studied oil shale plant contribute, however, to clearly higher total trace metal emission levels compared to modern coal fired power plants. Although the old electrostatic precipitators in the plant have been partly replaced by state-of-the-art electrostatic precipitators...... a two-fraction particle sampling and subsequent absorption of the gaseous fraction. The analyses were principally performed with ICP-MS techniques. The trace metal contents of Estonian oil shale were found to be in the same order of magnitude as of coal on average. The high total particle concentrations...

Polymer thin film as coating layer to prevent corrosion of metal/metal oxide film

Science.gov (United States)

Sarkar, Suman; Kundu, Sarathi

2018-04-01

Thin film of polymer is used as coating layer and the corrosion of metal/metal oxide layer is studied with the variation of the thickness of the coating layer. The thin layer of polystyrene is fabricated using spin coating method on copper oxide (CuO) film which is deposited on glass substrate using DC magnetron sputtering technique. Thickness of the polystyrene and the CuO layers are determined using X-ray reflectivity (XRR) technique. CuO thin films coated with the polystyrene layer are exposed to acetic acid (2.5 v/v% aqueous CH3COOH solution) environments and are subsequently analyzed using UV-Vis spectroscopy and atomic force microscopy (AFM). Surface morphology of the film before and after interaction with the acidic environment is determined using AFM. Results obtained from the XRR and UV-Vis spectroscopy confirm that the thin film of polystyrene acts as an anticorrosion coating layer and the strength of the coating depends upon the polymer layer thickness at a constant acid concentration.

Ideal femoral head size in total hip arthroplasty balances stability and volumetric wear.

Science.gov (United States)

Cross, Michael B; Nam, Denis; Mayman, David J

2012-10-01

Over the last several years, a trend towards increasing femoral head size in total hip arthroplasty to improve stability and impingement free range of motion has been observed. The specific questions we sought to answer in our review were: (1) What are the potential advantages and disadvantages of metal-on-metal, ceramic-on-ceramic, and metal-on-polyethylene bearings? (2) What is effect that femoral head size has on joint kinematics? (3) What is the effect that large femoral heads have on bearing surface wear? A PubMed search and a review of 2012 Orthopaedic Research Society abstracts was performed and articles were chosen that directly answered components of the specific aims and that reported outcomes with contemporary implant designs or materials. A review of the literature suggests that increasing femoral head size decreases the risk of postoperative dislocation and improves impingement free range of motion; however, volumetric wear increases with large femoral heads on polyethylene and increases corrosion of the stem in large metal-on-metal modular total hip arthroplasty (THA); however, the risk of potentially developing osteolysis or adverse reactions to metal debris respectively is still unknown. Further, the effect of large femoral heads with ceramic-on-ceramic THA is unclear, due to limited availability and published data. Surgeons must balance the benefits of larger head size with the increased risk of volumetric wear when determining the appropriate head size for a given patient.

Trace Metals in Urban Stormwater Runoff and their Management

Science.gov (United States)

Li, T.; Hall, K.; Li, L. Y.; Schreier, H.

2009-04-01

In past decades, due to the rapid urbanization, land development has replaced forests, fields and meadows with impervious surfaces such as roofs, parking lots and roads, significantly affecting watershed quality and having an impact on aquatic systems. In this study, non-point source pollution from a diesel bus loop was assessed for the extent of trace metal contamination of Cu, Mn, Fe, and Zn in the storm water runoff. The study was carried out at the University of British Columbia (UBC) in the Greater Vancouver Regional District (GVRD) of British Columbia, Canada. Fifteen storm events were monitored at 3 sites from the diesel bus loop to determine spatial and temporal variations of dissolved and total metal concentrations in the storm water runoff. The dissolved metal concentrations were compared with the provincial government discharge criteria and the bus loop storm water quality was also compared with previous studies conducted across the GVRD urban area. To prevent storm water with hazardous levels of contaminants from being discharged into the urban drainage system, a storm water catch basin filter was installed and evaluated for its efficiency of contaminants removal. The perlite filter media adsorption capacities for the trace metals, oil and grease were studied for better maintenance of the catch basin filter. Dissolved copper exceeded the discharge criteria limit in 2 out of 15 cases, whereas dissolved zinc exceeded the criteria in 4 out of 15 cases, and dissolved manganese was below the criteria in all of the events sampled. Dissolved Cu and Zn accounted for 36 and 45% of the total concentration, whereas Mn and Fe only accounted for 20 and 4% of their total concentration, respectively. Since they are more mobile and have higher bioaccumulation potentials, Zn and Cu are considered to be more hazardous to the aquatic environment than Fe and Mn. With high imperviousness (100%) and intensive traffic at the UBC diesel bus loop, trace metal concentrations

Repeated phytoextraction of four metal-contaminated soils using the cadmium/zinc hyperaccumulator Sedum plumbizincicola.

Science.gov (United States)

Li, Zhu; Wu, Longhua; Hu, Pengjie; Luo, Yongming; Zhang, Hao; Christie, Peter

2014-06-01

A cadmium/zinc hyperaccumulator extracted metals from four contaminated soils over three years in a glasshouse experiment. Changes in plant metal uptake and soil total (aqua regia-extractable) and available metals were investigated. Plant Cd concentrations in a high-Cd acid soil and plant Zn concentrations in two acid soils decreased during repeated phytoextraction and were predicted by soil available metal concentrations. However, on repeated phytoextraction, plant Cd concentrations remained constant in lightly Cd-polluted acid soils, as did plant Cd and Zn in alkaline soils, although soil available metal concentrations decreased markedly. After phytoextraction acid soils showed much higher total metal removal efficiencies, indicating possible suitability of phytoextraction for acid soils. However, DGT-testing, which takes soil metal re-supply into consideration, showed substantial removal of available metal and distinct decreases in metal supply capacity in alkaline soils after phytoextraction, suggesting that a strategy based on lowering the bioavailable contaminant might be feasible. Copyright © 2014 Elsevier Ltd. All rights reserved.

Plasma treatment of INEL soil contaminated with heavy metals

International Nuclear Information System (INIS)

Detering, B.A.; Batdorf, J.A.

1992-01-01

INEL soil spiked with inorganic salts of chromium, lead, mercury, silver, and zinc was melted in a 150 kW plasma furnace to produce a glassy slag product. This glassy slag is an environmentally safe waste form. In order to reduce the melting temperature of the soil, sodium carbonate was added to half of the test batches. Random sample from each batch of glassy slag product were analyzed by an independent laboratory for total metals concentration and leachability of metals via the Environmental Protection Agency (EPA) toxicity characterization leaching procedure (RCLP) tests. These tests showed the residual metals were very tightly bound to the slag matrix and were within EPA TCLP limits under these test conditions. Additionally, scanning electron microscopy (SEM) and emissions dispersive spectroscopy (EDS) analysis of the vitrified soil also confirmed that the added metals present in the vitrified soil were totally contained in the crystalline phase as distinct oxide crystallites

Half-metal phases in a quantum wire with modulated spin-orbit interaction

Science.gov (United States)

Cabra, D. C.; Rossini, G. L.; Ferraz, A.; Japaridze, G. I.; Johannesson, H.

2017-11-01

We propose a spin filter device based on the interplay of a modulated spin-orbit interaction and a uniform external magnetic field acting on a quantum wire. Half-metal phases, where electrons with only a selected spin polarization exhibit ballistic conductance, can be tuned by varying the magnetic field. These half-metal phases are proven to be robust against electron-electron repulsive interactions. Our results arise from a combination of explicit band diagonalization, bosonization techniques, and extensive density matrix renormalization group computations.

Biosolids and heavy metals in soils

Directory of Open Access Journals (Sweden)

Silveira Maria Lucia Azevedo

2003-01-01

Full Text Available The application of sewage sludge or biosolids on soils has been widespread in agricultural areas. However, depending on their characteristics, they may cause increase in heavy metal concentration of treated soils. In general, domestic biosolids have lower heavy metal contents than industrial ones. Origin and treatment method of biosolids may markedly influence their characteristics. The legislation that controls the levels of heavy metal contents in biosolids and the maximum concentrations in soils is still controversial. In the long-term, heavy metal behavior after the and of biosolid application is still unknown. In soils, heavy metals may be adsorbed via specific or non-specific adsorption reactions. Iron oxides and organic matter are the most important soil constituents retaining heavy metals. The pH, CEC and the presence of competing ions also affect heavy metal adsorption and speciation in soils. In solution, heavy metals can be present either as free-ions or complexed with organic and inorganic ligands. Generally, free-ions are more relevant in environmental pollution studies since they are readily bioavailable. Some computer models can estimate heavy metal activity in solution and their ionic speciation. Thermodynamic data (thermodynamic stability constant, total metal and ligand concentrations are used by the GEOCHEM-PC program. This program allows studying heavy metal behavior in solution and the effect of changes in the conditions, such as pH and ionic strength and the application of organic and inorganic ligands caused by soil fertilization.

The Unsafe Acts and the Decision-to-Err Factors of Thai Construction Workers

OpenAIRE

Thanet Aksorn; B.H.W. Hadikusumo

2007-01-01

The unsafe acts of workers are considered as major contributors of work-related accidents and injuries on construction sites. However, not much work has been done to address the reasons why unsafe acts of workers occur particularly in construction industry. The aim of this paper therefore, is to investigate the major unsafe acts (i.e., at-risk behavior), and the decision-to-err factors causing unsafe acts. A questionnaire survey was conducted to collect data from a total of 214 workers from 2...

Heavy metals contamination of soils in response to wastewater irrigation in Rawalpindi region

International Nuclear Information System (INIS)

Mushtaq, N.; Khan, K.S.

2010-01-01

The study was conducted to evaluate the quality of effluents/ waste water samples from Rawalpindi region for irrigation purpose and to elucidate effects of their application on heavy metal contents in soils of area. Results indicated that the EC, SAR, RSC and TDS of most effluent/ waste water samples were above the critical limits. Cadmium and Cr were above the critical limits in almost all the effluent samples, whereas Ni was high in 14, Pb was high in 10, Cu was high in 5 and the Fe was high in 3 effluent samples as compared to critical limits. Regarding heavy metals contents of soils irrigated by these effluents/ waste water, total Fe, total Cd and total Ni were higher in almost all the sampled sites, whereas total Cr was high at 7 sampled sites. AB-DTPA extractable Fe and Zn were higher at all the sampled sites, while the extractable Cd was higher at 2 sampled sites. Overall, the effluent samples collected from Adiala showed high concentrations of heavy metals, whereas soils of Wah factory and Islamabad area had higher heavy metal contents (total and AB-DTPA extractable). On the basis of results it is concluded that quality of effluents/ waste water samples collected from different locations of Rawalpindi is not good for irrigation and the long term use of these effluents for crop production caused accumulation of some toxic metals in soils above critical limits which is harmful for soil health and may lead to elevated levels of heavy metals in crop plants. (author)

Self-excitation of Rydberg atoms at a metal surface

DEFF Research Database (Denmark)

Bordo, Vladimir

2017-01-01

The novel effect of self-excitation of an atomic beam propagating above a metal surface is predicted and a theory is developed. Its underlying mechanism is positive feedback provided by the reflective surface for the atomic polarization. Under certain conditions the atomic beam flying in the near...... field of the metal surface acts as an active device that supports sustained atomic dipole oscillations, which generate, in their turn, an electromagnetic field. This phenomenon does not exploit stimulated emission and therefore does not require population inversion in atoms. An experiment with Rydberg...... atoms in which this effect should be most pronounced is proposed and the necessary estimates are given....

Photoluminescence emission from Alq3 organic layer in metal–Alq3–metal plasmonic structure

Energy Technology Data Exchange (ETDEWEB)

Huang, Bohr-Ran; Liao, Chung-Chi [Graduate Institute of Electro-Optical Engineering and Department of Electronic Engineering, National Taiwan University of Science and Technology, Taipei 106, Taiwan (China); Fan, Wan-Ting [Institute of Electro-Optical Engineering and Department of Electronic Engineering, Chang Gung University, Tao-Yuan 333, Taiwan (China); Wu, Jin-Han; Chen, Cheng-Chang; Lin, Yi-Ping; Li, Jung-Yu; Chen, Shih-Pu [Green Energy and Environment Research Laboratories, Industrial Technology Research Institute (ITRI), 195, Sec. 4, Chung-Hsin Road, Chutung 310, Taiwan (China); Ke, Wen-Cheng [Department of Mechanical Engineering, Yuan Ze University, Tao-Yuan 320, Taiwan (China); Chen, Nai-Chuan, E-mail: ncchen001@mail.cgu.edu.tw [Institute of Electro-Optical Engineering and Department of Electronic Engineering, Chang Gung University, Tao-Yuan 333, Taiwan (China)

2014-06-01

The emission properties of an organic layer embedded in a metal–organic–metal (MOM) structure were investigated. A partially radiative odd-SPW as well as a non-radiative even-SPW modes are supported by hybridization of the SPW modes on the opposite organic/metal interface in the structure. Because of the competition by this radiative SPW, the population of excitons that recombine to form non-radiative SPW should be reduced. This may account for why the photoluminescence intensity of the MOM sample is higher than that of an organic–metal sample even though the MOM sample has an additional metal layer that should intuitively act as a filter.

Calculation of forces acting on an impurity in a metal subjected to a temperature gradient

International Nuclear Information System (INIS)

Gerl, M.

1966-01-01

In a metal subject to a temperature gradient, an impurity is submitted to both an electrostatic force due to the thermoelectric field and a force due to the scattering of electrons and phonons by this point defect. The scattering of the electrons is treated using a semi-classical approach and a quantum mechanical method. The numerical computation for several impurities in Cu, Ag, and Au requires the knowledge of the resistivity cross-section. and of the thermoelectric power of the impurity in the metal. A tentative estimation of the force due to the phonon-scattering is given for the self-diffusion in Cu. However, the approximations of this calculation do not allow a good comparison with the force due to the electrons. (author) [fr

29 CFR 779.253 - What is included in computing the total annual inflow volume.

Science.gov (United States)

2010-07-01

... FAIR LABOR STANDARDS ACT AS APPLIED TO RETAILERS OF GOODS OR SERVICES Employment to Which the Act May... taxes and other charges which the enterprise must pay for such goods. Generally, all charges will be... computing the total annual inflow volume. The goods which the establishment purchases or receives for resale...

Oxalate metal complexes in aerosol particles: implications for the hygroscopicity of oxalate-containing particles

Directory of Open Access Journals (Sweden)

T. Furukawa

2011-05-01

Full Text Available Atmospheric aerosols have both a direct and an indirect cooling effect that influences the radiative balance at the Earth's surface. It has been estimated that the degree of cooling is large enough to weaken the warming effect of carbon dioxide. Among the cooling factors, secondary organic aerosols (SOA play an important role in the solar radiation balance in the troposphere as SOA can act as cloud condensation nuclei (CCN and extend the lifespan of clouds because of their high hygroscopic and water soluble nature. Oxalic acid is an important component of SOA, and is produced via several formation pathways in the atmosphere. However, it is not certain whether oxalic acid exists as free oxalic acid or as metal oxalate complexes in aerosols, although there is a marked difference in their solubility in water and their hygroscopicity. We employed X-ray absorption fine structure spectroscopy to characterize the calcium (Ca and zinc (Zn in aerosols collected at Tsukuba in Japan. Size-fractionated aerosol samples were collected for this purpose using an impactor aerosol sampler. It was shown that 10–60% and 20–100% of the total Ca and Zn in the finer particles (<2.1 μm were present as Ca and Zn oxalate complexes, respectively. Oxalic acid is hygroscopic and can thus increase the CCN activity of aerosol particles, while complexes with various polyvalent metal ions such as Ca and Zn are not hygroscopic, which cannot contribute to the increase of the CCN activity of aerosols. Based on the concentrations of noncomplexed and metal-complexed oxalate species, we found that most of the oxalic acid is present as metal oxalate complexes in the aerosols, suggesting that oxalic acid does not always increase the hygroscopicity of aerosols in the atmosphere. Similar results are expected for other dicarboxylic acids, such as malonic and succinic acids. Thus, it is advisable that the cooling effect of organic aerosols should be estimated by including the

Trophic transfer of trace metals: Subcellular compartmentalization in a polychaete and assimilation by a decapod crustacean

Science.gov (United States)

Rainbow, P.S.; Poirier, L.; Smith, B.D.; Brix, K.V.; Luoma, S.N.

2006-01-01

The chemical form of accumulated trace metal in prey is important in controlling the bioavailataility of dietary metal to a predator. This study investigated the trophic transfer of radiolabelled Ag, Cd and Zn from the polychaete worm Nereis diversicolor to the decapod crustacean Palaemonetes varians. We used 2 populations of worms with different proportions of accumulated metals in different subcellular fractions as prey, and loaded the worms with radiolabelled metals either from sediment or from solution. Accumulated radiolabelled metals were fractionated into 5 components : metal-rich granules (MRG), cellular debris, organelles, metallothionein-like proteins (MTLP), and other (heat-sensitive) proteins (HSP). Assimilation efficiencies (AE) of the metals by P. varians were measured from the 4 categories of prey (i.e. 2 populations, radiolabelled from sediment or solution). There were significant differences for each metal between the AEs from the different prey categories, confirming that origin of prey and route of uptake of accumulated trace metal will cause intraspecific differences in subsequent metal assimilation. Correlations were sought between AEs and selected fractions or combinations of fractions of metals in the prey-MRG, Trophically Available Metal (TAM = MTLP + HSP + organelles) and total protein (MTLP + HSP). TAM explained 28% of the variance in AEs for Ag, but no consistent relationships emerged between AEs and TAM or total protein when the metals were considered separately. AEs did, however, show significant positive regressions with both TAM and total protein when the 3 metals were considered together, explaining only about 21 % of the variance in each case. A significant negative relationship was observed between MRG and AE for all metals combined. The predator (P. varians) can assimilate dietary metal from a range of the fractions binding metals in the prey (N. diversicolor), with different assimilation efficiencies summated across these

High performance bulk metallic glass/carbon nanotube composite cathodes for electron field emission

International Nuclear Information System (INIS)

Hojati-Talemi, Pejman; Gibson, Mark A.; East, Daniel; Simon, George P.

2011-01-01

We report the preparation of new nanocomposites based on a combination of bulk metallic glass and carbon nanotubes for electron field emission applications. The use of bulk metallic glass as the matrix ensures high electrical and thermal conductivity, high thermal stability, and ease of processing, whilst the well dispersed carbon nanotubes act as highly efficient electron emitters. These advantages, alongside excellent electron emission properties, make these composites one of the best reported options for electron emission applications to date.

High performance bulk metallic glass/carbon nanotube composite cathodes for electron field emission

Energy Technology Data Exchange (ETDEWEB)

Hojati-Talemi, Pejman [Department of Materials Engineering, Monash University, Clayton, Vic 3800 (Australia); Mawson Institute, University of South Australia, Mawson Lakes, SA 5095 (Australia); Gibson, Mark A. [Process Science and Engineering, Commonwealth Scientific and Industrial Research Organisation, Clayton, Vic 3168 (Australia); East, Daniel; Simon, George P. [Department of Materials Engineering, Monash University, Clayton, Vic 3800 (Australia)

2011-11-07

We report the preparation of new nanocomposites based on a combination of bulk metallic glass and carbon nanotubes for electron field emission applications. The use of bulk metallic glass as the matrix ensures high electrical and thermal conductivity, high thermal stability, and ease of processing, whilst the well dispersed carbon nanotubes act as highly efficient electron emitters. These advantages, alongside excellent electron emission properties, make these composites one of the best reported options for electron emission applications to date.

Concentration of metals in fishes from Thane and Bassein creeks of Bombay, India

Digital Repository Service at National Institute of Oceanography (India)

Krishnamurti, A.J.; Nair, V.R.

-58% to the total metals accumulated. Maximum concentration of all metals was found either in liver or in alimentary canal with lowest level in muscle tissue. Though metal accumulation was found to be species specific maximum concentrations were found in bottom...

Bioavailability of cyanide and metal-cyanide mixtures to aquatic life.

Science.gov (United States)

Redman, Aaron; Santore, Robert

2012-08-01

Cyanide can be toxic to aquatic organisms, and the U.S. Environmental Protection Agency has developed ambient water-quality criteria to protect aquatic life. Recent work suggests that considering free, rather than total, cyanide provides a more accurate measure of the biological effects of cyanides and provides a basis for water-quality criteria. Aquatic organisms are sensitive to free cyanide, although certain metals can form stable complexes and reduce the amount of free cyanide. As a result, total cyanide is less toxic when complexing metals are present. Cyanide is often present in complex effluents, which requires understanding how other components within these complex effluents can affect cyanide speciation and bioavailability. The authors have developed a model to predict the aqueous speciation of cyanide and have shown that this model can predict the toxicity of metal-cyanide complexes in terms of free cyanide in solutions with varying water chemistry. Toxicity endpoints based on total cyanide ranged over several orders of magnitude for various metal-cyanide mixtures. However, predicted free cyanide concentrations among these same tests described the observed toxicity data to within a factor of 2. Aquatic toxicity can be well-described using free cyanide, and under certain conditions the toxicity was jointly described by free cyanide and elevated levels of bioavailable metals. Copyright © 2012 SETAC.

Total and labile metals in surface sediments of the tropical river-estuary system of Marabasco (Pacific coast of Mexico): Influence of an iron mine.

Science.gov (United States)

Marmolejo-Rodríguez, Ana Judith; Prego, Ricardo; Meyer-Willerer, Alejandro; Shumilin, Evgueni; Cobelo-García, Antonio

2007-01-01

Marabasco is a tropical river-estuary system comprising the Marabasco river and the Barra de Navidad Lagoon. The river is impacted by the Peña Colorada iron mine, which produces 3.5 million tons of pellets per year. Thirteen surface sediment samples were collected in May 2005 (dry season) in order to establish background levels of Al, Cd, Co, Cu, Fe, Ni, Pb, and Zn in the system and to ascertain the potential mobility of metals in the sediments. Analyses were carried out in the fraction finer than 63 microm, and labile metals extracted according the BCR procedure. Certified reference materials were used for validation of methods. Total concentrations of Cd, Co, Cu, Ni, Pb, and Zn were in the range of 0.05-0.34, 6-95, 0.7-31, 9-26, 2-18, and 53-179 mgkg(-1), respectively; Al and Fe ranges of 24-127, and 26-69 mgg(-1) correspondingly. Cadmium was found to be significantly labile in the sediments (20-100%), followed by Co (0-35%), Ni (3-16%) and Zn (0-25%), whereas the labile fraction for Cu, Fe and Pb was almost negligible (iron mine on the Marabasco system is lower than expected when compared with other similar World systems influenced by mining activities.

Robust half-metallicity of hexagonal SrNiO_3

International Nuclear Information System (INIS)

Chen, Gao-Yuan; Ma, Chun-Lan; Chen, Da; Zhu, Yan

2016-01-01

In the rich panorama of the electronic and magnetic properties of 3d transition metal oxides SrMO_3 (M=Ti, V, Cr, Mn, Fe, Co, Ni, Cu), one member (SrNiO_3) is missing. In this paper we use GGA+U method based on density functional theory to examine its properties. It is found that SrNiO_3 is a ferromagnetic half-metal. The charge density map shows a high degree of ionic bonding between Sr and other atoms. Meanwhile, a covalent-bonding Ni–O–Ni–O–Ni chain is observed. The spin density contour of SrNiO_3 further indicates that the magnetic interaction between Ni atoms mediated by O is semicovalent exchange. The density of states are examined to explore the unusual indirect magnetic-exchange mechanism. Corresponding to the total energies results, a robust half-metallic character is observed, suggesting a promising giant magneto-optical Kerr property of the material. The partial density of states are further examined to explore the origin of ferromagnetic half-metallicity. The O atoms are observed to have larger contribution at fermi level than Ni atoms to the spin-polarized states, demonstrating that O atoms play a critical role in ferromagnetic half-metallicity of SrNiO_3. Hydrostatic pressure effect is examined to evaluate how robust the half-metallic ferromagnetism is. - Graphical abstract: (a) The total energy as a function of the lattice constant a for hexagonal SrNiO3 with various magnetic phases. (b) The total electronic density of states for hexagonal SrNiO_3 with FM configuration from GGA+U calculations. (c) Total electron-density distribution in the (110) plane. The colors gradually change from cyan (through pink) to yellow corresponding to charge density value from 0 to 4.0. (d) The magnetization density map in the (110) plane. The colors range from blue (through green) to red corresponding to magnetization density value from −0.15 to 0.45. Black and white contours stand for positive and negative values, respectively. - Highlights: • Hexagonal Sr

Macromolecules containing bipyridine and terpyridine metal complexes: towards metallo-supramolecular polymers

NARCIS (Netherlands)

Schubert, U.S.; Eschbaumer, C.

2002-01-01

The ability of a broad range of N-heterocycles to act as very effective and stable complexation agents for several transition metal ions, such as cobalt(II), copper(II), nickel(II), and ruthenium(II), has long been known in analytical chemistry. This behavior was later utilized in supramolecular

ELECTED PROBLEMS RELATED TO ENVIRONMENTAL HEAVY METALS EXPOSURE AND CHELATION THERAPY

Directory of Open Access Journals (Sweden)

Anna Skoczyńska

2010-09-01

Full Text Available Background: Exposure to heavy metals leads to functional and metabolic disturbances and many of them are included in pathogenesis of common diseases (arterial hypertension, atherosclerosis, neurodegenerative processes. In this context new therapeutic and prophylactic strategies are necessary. Patients diagnosed with chronic heavy metals intoxication usually require chelation to increase mobilisation of metals from tissues and elimination of them via urine. Acute poisoning with toxic metal may be difficult to diagnosis, especially in case of accidental intoxication or suicidal intention. Patients also require chelation after causative factor is identified. Objectives: To describe some problems connected with toxicity of metals poisoning and to review pharmacologic therapies that could have a role in poisoning with metals. Methods: A review of the literature was carried out and expert opinion expressed. Results/conclusion: Chelation is a common therapy in case of poisoning with toxic metals but it is satisfied only partially. A combined therapy with structurally different chelators or long-term acting chelators could become viable alternatives in the future. A combined therapy with an antioxidant plus chelator may be a good choice in patients chronically poisoned with metals. Exposure to lead should be taken into account during estimation of global cardiovascular risk.

Atomic Energy Commission Act, 2000 (Act 588)

International Nuclear Information System (INIS)

2000-01-01

Act 588 of the Republic of Ghana entitled, Atomic Energy Commission Act, 2000, amends and consolidates the Atomic Energy Commission Act, 204 of 1963 relating to the establishment of the Atomic Energy Commission. Act 588 makes provision for the Ghana Atomic Energy Commission to establish more institutes for the purpose of research in furtherance of its functions and also promote the commercialization of its research and development results. (E.A.A.)

Exotic species with explicit noble metal-noble gas-noble metal linkages.

Science.gov (United States)

Moreno, Norberto; Restrepo, Albeiro; Hadad, C Z

2018-02-14

We present a study of the isoelectronic Pt 2 Ng 2 F 4 and [Au 2 Ng 2 F 4 ] 2+ species with noble gas atoms (Ng = Kr, Xe, Rn) acting as links bridging the two noble metal atoms. The stability of the species is investigated using several thermodynamic, kinetic and reactivity indicators. The results are compared against [AuXe 4 ] 2+ , which is thermodynamically unstable in the gas phase but is stabilized in the solid state to the point that it has been experimentally detected as [AuXe 4 ](Sb 2 F 11 ) 2 (S. Seidel and K. Seppelt, Science, 2000, 290, 117-118). Our results indicate that improving upon [AuXe 4 ] 2+ , these exotic combinations between the a priori non-reactive noble metals and noble gases lead to metastable species, and, therefore, they have the possibility of existing in the solid state under adequate conditions. Our calculations include accurate energies and geometries at both the CCSD/SDDALL and MP2/SDDALL levels. We offer a detailed description of the nature of the bonding interactions using orbital and density-based analyses. The computational evidence suggests partially covalent and ionic interactions as the stabilization factors.

A comprehensive study of metal distribution in three main classes of seaweed

International Nuclear Information System (INIS)

Ryan, Siobhan; McLoughlin, Peter; O'Donovan, Orla

2012-01-01

This paper provides one of the most comprehensive studies of metal distributions in three main macroalgae species. In this novel study, levels of total, intracellular and surface bound Pb, Zn, As, Cd, Co, Cr, Cu, Mn and Ni associated with Polysiphonia lanosa (L) Tandy, Ascophyllum nodosum (L) Le Jolis, Fucus vesiculosus (L) and Ulva sp. were determined. Additionally, water and sediment metal levels were analysed to gain an insight into the relative uptake efficiencies of different macroalgal species. Samples were collected from a clean site in Fethard-on-Sea, Wexford, Ireland (52°11′53.68′N, 6°49′34.64′W), in May 2008. Results demonstrated that total, intracellular and surface bound metal levels varied according to metal and seaweed species, with the highest proportion of metals found to be intracellular. Inhibition of Mn uptake by Zn was indicated for P. lanosa. Furthermore, P. lanosa had enhanced bioaccumulation ability, with the highest Concentration Factor reported of any seaweed to date. - Highlights: ► Three main classes of seaweed were collected from the South-East coast of Ireland. ► Metal levels (total, intracellular and surface-bound) in four seaweed species were determined. ► Metal levels of seawater and sediment samples collected from the same location were quantified. ► The Concentration Factors for P. lanosa, A. nodosum, F. vesiculosus and Ulva sp., were calculated. ► Interspecies variations in seaweed metal concentrations were demonstrated. - This study, reports the most comprehensive uptake efficiencies and distributions of metals in four main seaweed sps., with P. lanosa demonstrating excellent bioaccumulation ability.

Rare-earth-metal nitridophosphates through high-pressure metathesis

International Nuclear Information System (INIS)

Kloss, Simon David; Schnick, Wolfgang

2015-01-01

Developing a synthetic method to target an broad spectrum of unknown phases can lead to fascinating discoveries. The preparation of the first rare-earth-metal nitridophosphate LiNdP_4N_8 is reported. High-pressure solid-state metathesis between LiPN_2 and NdF_3 was employed to yield a highly crystalline product. The in situ formed LiF is believed to act both as the thermodynamic driving force and as a flux to aiding single-crystal formation in dimensions suitable for crystal structure analysis. Magnetic properties stemming from Nd"3"+ ions were measured by SQUID magnetometry. LiNdP_4N_8 serves as a model system for the exploration of rare-earth-metal nitridophosphates that may even be expanded to transition metals. High-pressure metathesis enables the systematic study of these uncharted regions of nitride-based materials with unprecedented properties. (copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Sulfide oxidation and the natural attenuation of arsenic and trace metals in the waste rocks of the abandoned Seobo tungsten mine, Korea

International Nuclear Information System (INIS)

Lee, Pyeong-koo; Kang, Min-Ju; Choi, Sang-Hoon; Touray, Jean-Claude

2005-01-01

Mineralogical examinations were performed to characterize the formation of secondary minerals and natural removal process of dissolved As and trace metals (Pb, Zn and Cu) from sulfide oxidation. Laboratory-based leaching tests were also conducted to determine whether the concentrations of As and trace metals in the leachates from waste-rock materials and contaminated soil could be affected by the presence acids such as acid rainwater or acid mine drainage. Waste-rock materials and contaminated soil were compared by 4-day leaching tests using HNO 3 solutions of increasing acidity (0.00001-0.1mole/L). Mineralogical studies of the waste rocks confirmed the presence of Fe-(oxy)hydroxides (e.g. goethite), jarosite, elemental S, Fe-sulfates, amorphous Fe-As phases, anglesite and covellite as secondary minerals. These secondary minerals act as mineralogical scavengers of dissolved trace metals, SO 4 2- and acidity released by sulfide oxidation. Arsenic was attenuated by the adsorption on Fe-(oxy)hydroxides and/or the formation of an amorphous Fe-As phase, with a Fe/As ratio=1 (maybe scorodite: FeAsO 4 .2H 2 O). Electron probe microanalyses data showed that the Fe-(oxy)hydroxides had high concentrations of Pb (up to 21wt%), with appreciable amounts of As (up to 7.7wt%), Zn (up to 4.6wt%) and Cu (up to 2.5wt%) indicating that dissolved metals were co-precipitated and adsorbed onto Fe-(oxy)hydroxides, Fe(Mn)-hydroxides and Fe-sulfates. The results of the leaching experiments within the pH-range 3.5-5.0 indicated that acidic rainstorms may leach minor amounts of Pb (ca. 1.7-4.0% of total), Zn (ca. 0.8-2.2% of total), Cu (ca. 0.0-0.2% of total) and As (ca. 0.02-0.1% of total) from waste rocks, including the dissolution of soluble secondary minerals previously formed during prolonged dry periods, while dissolution of these elements was negligible from the contaminated soil. In the pH-range 1.0-3.0, the leaching of Pb (ca. 2.4-31% of total) and As (ca. 0.1-5.8% of total) from

Fiscal 2000 report on result of R and D of nonmetallic material recycling promotion technology (demonstration test and research, total system technology); 2000 nendo hitetsu kinzokukei sozai recycle sokushin gijutsu kenkyu kaihatsu seika hokokusho. Jissho shiken kenkyu, total system gijutsu

Energy Technology Data Exchange (ETDEWEB)

NONE

2001-03-01

R and D was conducted on advanced recycling technology for aluminum and base metal/rare metal based materials, with fiscal 2000 results compiled. In the research of aluminum recycling technology, on a continuous fractional crystallization process and a purification by zinc removal process, the existing facilities for each demonstrated that they could simulate an aluminum scrap melting process capacity of 1,000 t/month, with a series of initial conditions determined. In the research of total system technology, combined test facilities were completed in which a purification process and a melt cleaning process were integrated. In the research of the recycling technology for base metal/rare metal based materials, a test was carried out by demonstrative facilities, with the aim of establishing copper regeneration technology in which high grade copper is produced using metal/resin based scraps such as shredder dust of automobiles as the materials. In structuring the total system technology, a preliminary survey and environmental load measures were carried out toward the practicability of a comprehensive copper metal collection recycling system. (NEDO)

Both heavy metal-amendment of soil and aphid-infestation increase Cd and Zn concentrations in phloem exudates of a metal-hyperaccumulating plant.

Science.gov (United States)

Stolpe, Clemens; Giehren, Franziska; Krämer, Ute; Müller, Caroline

2017-07-01

Plants that are able to hyperaccumulate heavy metals show increased concentrations of these metals in their leaf tissue. However, little is known about the concentrations of heavy metals and of organic defence metabolites in the phloem sap of these plants in response to either heavy metal-amendment of the soil or biotic challenges such as aphid-infestation. In this study, we investigated the effects of heavy metal-exposure and of aphid-infestation on phloem exudate composition of the metal hyperaccumulator species Arabidopsis halleri L. O'Kane & Al-Shehbaz (Brassicaceae). The concentrations of elements and of organic defence compounds, namely glucosinolates, were measured in phloem exudates of young and old (mature) leaves of plants challenged either by amendment of the soil with cadmium and zinc and/or by an infestation with the generalist aphid Myzus persicae. Metal-amendment of the soil led to increased concentrations of Cd and Zn, but also of two other elements and one indole glucosinolate, in phloem exudates. This enhanced defence in the phloem sap of heavy metal-hyperaccumulating plants can thus potentially act as effective protection against aphids, as predicted by the elemental defence hypothesis. Aphid-infestation also caused enhanced Cd and Zn concentrations in phloem exudates. This result provides first evidence that metal-hyperaccumulating plants can increase heavy metal concentrations tissue-specifically in response to an attack by phloem-sucking herbivores. Overall, the concentrations of most elements, including the heavy metals, and glucosinolates were higher in phloem exudates of young leaves than in those of old leaves. This defence distribution highlights that the optimal defence theory, which predicts more valuable tissue to be better defended, is applicable for both inorganic and organic defences. Copyright © 2017 Elsevier Ltd. All rights reserved.

Revision total hip arthoplasty: factors associated with re-revision surgery.

Science.gov (United States)

Khatod, Monti; Cafri, Guy; Inacio, Maria C S; Schepps, Alan L; Paxton, Elizabeth W; Bini, Stefano A

2015-03-04

highly cross-linked polyethylene bearing articulation decreases the hazard relative to metal on highly cross-linked polyethylene by a factor of 0.32 (95% confidence interval, 0.11 to 0.95). Metal on constrained bearing increases the hazard relative to metal on highly cross-linked polyethylene by a factor of 3.32 (95% confidence interval, 1.16 to 9.48). When evaluating patient, implant, and surgical factors at the time of revision total hip arthroplasty, age, surgeon experience, implant fixation, and bearing surfaces had significant impacts on the risk of re-revision. Copyright © 2015 by The Journal of Bone and Joint Surgery, Incorporated.

Toxic metals in WEEE: Characterization and substance flow analysis in waste treatment processes

Energy Technology Data Exchange (ETDEWEB)

Oguchi, Masahiro, E-mail: oguchi.masahiro@nies.go.jp; Sakanakura, Hirofumi; Terazono, Atsushi

2013-10-01

Waste electrical and electronic equipment (WEEE) has received extensive attention as a secondary source of metals. Because WEEE also contains toxic substances such as heavy metals, appropriate management of these substances is important in the recycling and treatment of WEEE. As a basis for discussion toward better management of WEEE, this study characterizes various types of WEEE in terms of toxic metal contents. The fate of various metals contained in WEEE, including toxic metals, was also investigated in actual waste treatment processes. Cathode-ray tube televisions showed the highest concentration and the largest total amount of toxic metals such as Ba, Pb, and Sb, so appropriate recycling and disposal of these televisions would greatly contribute to better management of toxic metals in WEEE. A future challenge is the management of toxic metals in mid-sized items such as audio/visual and ICT equipment because even though the concentrations were not high in these items, the total amount of toxic metals contained in them is not negligible. In the case of Japan, such mid-sized WEEE items as well as small electronic items are subject to municipal solid waste treatment. A case study showed that a landfill was the main destination of toxic metals contained in those items in the current treatment systems. The case study also showed that changes in the flows of toxic metals will occur when treatment processes are modified to emphasize resource recovery. Because the flow changes might lead to an increase in the amount of toxic metals released to the environment, the flows of toxic metals and the materials targeted for resource recovery should be considered simultaneously. - Highlights: ► Appropriate management of toxic metals contained in WEEE is important during recycling and treatment of WEEE. ► CRT TVs contain large amount of toxic metals with high concentration and thus appropriate management is highly important. ► Mid-sized equipment is a future target for

Relations between variously available fractions of trace metals in the soil and their actual plant-uptake

International Nuclear Information System (INIS)

Bujtas, K.; Csillag, J.

1999-01-01

In a pot experiment, availabilities of Cd, Cr, Ni, Pb, and Zn added to the soil as metal nitrates or as enrichment of sewage sludge were evaluated by comparing concentrations of their total potentially available, presumably plant-available and directly plant-available forms in the soil. At excessively increasing soil contamination, the plant-available concentrations increased more than the total soil contents, thus the relative availabilities of the metals increased. This was reflected in the amounts taken up by the young maize test plants and in the plant/soil transfer factors. Transfer factors calculated for the 'plant-available' soil metal contents depended less on the contamination level than those based on total soil metal contents. Refs. 8 (author)

17 CFR 270.5b-1 - Definition of “total assets.”

Science.gov (United States)

2010-04-01

... (CONTINUED) RULES AND REGULATIONS, INVESTMENT COMPANY ACT OF 1940 § 270.5b-1 Definition of “total assets... 17 Commodity and Securities Exchanges 3 2010-04-01 2010-04-01 false Definition of âtotal assets.â..., shall mean the gross assets of the company with respect to which the computation is made, taken as of...

Bioaccumulation of heavy metals in plant leaves from Yan׳an city of the Loess Plateau, China.

Science.gov (United States)

Hu, Youning; Wang, Dexiang; Wei, Lijing; Zhang, Xinping; Song, Bin

2014-12-01

Urban plants are capable of reducing environmental pollutions through bioaccumulation contaminants in their tissues. The accumulation of heavy metals (Pb, Cu, Cd, Cr, and Zn) in leaves of nine tree species and five shrub species from Yan׳an city of China were investigated, and total metal accumulation capacities of different plants were evaluated using the metal accumulation index (MAI). The results indicated that plants in polluted environments are enriched in heavy metals relative to those in pristine environments, this is mainly caused by traffic emissions and coal combustion. Species with the highest accumulation of a single metal did not have the highest total metal accumulation capacity, the MAI should be an important indicator for tree species selection in phytoextraction and urban greening. Considering total accumulation capacities, Sabina chinensis, Juniperus formosana, Ailanthus altissima and Salix matsudana var. matsudana could be widely used in the Loess Plateau. Copyright © 2014 Elsevier Inc. All rights reserved.

Release of Radioactive Scrap Metal/Scrap Metal (RSM/SM) at Nevada Test Site (NTS)

International Nuclear Information System (INIS)

1993-01-01

Reynolds Electrical and Engineering Company, Inc. (REECo) is the prime contractor to the US Department of Energy (DOE) in providing service and support for NTS operations. Mercury Base Camp is the main control point for the many forward areas at NTS, which covers 1,350 square miles. The forward areas are where above-ground and underground nuclear tests have been performed over the last 41 years. No metal (or other material) is returned to Mercury without first being tested for radioactivity. No radioactive metals are allowed to reenter Mercury from the forward areas, other than testing equipment. RAMATROL is the monitor check point. They check material in various ways, including swipe tests, and have a large assortment of equipment for testing. Scrap metal is also checked to address Resource Conservation and Recovery Act concerns. After addressing these issues, the scrap metals are categorized. Federal Property Management Regulations (FPMR) are followed by REECo. The nonradioactive scrap material is sold through the GSA on a scheduled basis. Radioactive scrap metal are presently held in forward areas where they were used. REECo has gained approval of their Nevada Test Site Defense Waste Acceptance Criteria, Certification, and Transfer Requirements, NVO-325 application, which will allow disposal on site, when RSM is declared a waste. The guideline that REECo uses for release limits is DOE Order 5480.11, Radiation Protection for Occupational Works, Attachment 2, Surface Radioactivity Guides, of this order, give release limits for radioactive materials. However, the removal of radioactive materials from NTS require approval by DOE Nevada Operations Office (DOE/NV) on a case-by-case basis. Requirements to consider before removal are found in DOE Order 5820.2A, Radioactive Waste Management

Mapping the Galvanic Corrosion of Three Metals Coupled with a Wire Beam Electrode: The Influence of Temperature and Relative Geometrical Position

Science.gov (United States)

Liu, Yun-Fei; Liu, Shu-Fa; Duan, Jin-Zhuo

2018-01-01

The local electrochemical properties of galvanic corrosion for three coupled metals in a desalination plant were investigated with three wire-beam electrodes as wire sensors: aluminum brass (HAl77-2), titanium (TA2), and 316L stainless steel (316L SS). These electrodes were used with artificial seawater at different temperatures. The potential and current–density distributions of the three-metal coupled system are inhomogeneous. The HAl77-2 wire anodes were corroded in the three-metal coupled system. The TA2 wires acted as cathodes and were protected; the 316L SS wires acted as secondary cathodes. The temperature and electrode arrangement have important effects on the galvanic corrosion of the three-metal coupled system. The corrosion current of the HAl77-2 increased with temperature indicating enhanced anode corrosion at higher temperature. In addition, the corrosion of HAl77-2 was more significant when the HAl77-2 wires were located in the middle of the coupled system than with the other two metal arrangement styles. PMID:29495617

Mapping the Galvanic Corrosion of Three Metals Coupled with a Wire Beam Electrode: The Influence of Temperature and Relative Geometrical Position.

Science.gov (United States)

Ju, Hong; Yang, Yuan-Feng; Liu, Yun-Fei; Liu, Shu-Fa; Duan, Jin-Zhuo; Li, Yan

2018-02-28

The local electrochemical properties of galvanic corrosion for three coupled metals in a desalination plant were investigated with three wire-beam electrodes as wire sensors: aluminum brass (HAl77-2), titanium (TA2), and 316L stainless steel (316L SS). These electrodes were used with artificial seawater at different temperatures. The potential and current-density distributions of the three-metal coupled system are inhomogeneous. The HAl77-2 wire anodes were corroded in the three-metal coupled system. The TA2 wires acted as cathodes and were protected; the 316L SS wires acted as secondary cathodes. The temperature and electrode arrangement have important effects on the galvanic corrosion of the three-metal coupled system. The corrosion current of the HAl77-2 increased with temperature indicating enhanced anode corrosion at higher temperature. In addition, the corrosion of HAl77-2 was more significant when the HAl77-2 wires were located in the middle of the coupled system than with the other two metal arrangement styles.

Mapping the Galvanic Corrosion of Three Metals Coupled with a Wire Beam Electrode: The Influence of Temperature and Relative Geometrical Position

Directory of Open Access Journals (Sweden)

Hong Ju

2018-02-01

Full Text Available The local electrochemical properties of galvanic corrosion for three coupled metals in a desalination plant were investigated with three wire-beam electrodes as wire sensors: aluminum brass (HAl77-2, titanium (TA2, and 316L stainless steel (316L SS. These electrodes were used with artificial seawater at different temperatures. The potential and current–density distributions of the three-metal coupled system are inhomogeneous. The HAl77-2 wire anodes were corroded in the three-metal coupled system. The TA2 wires acted as cathodes and were protected; the 316L SS wires acted as secondary cathodes. The temperature and electrode arrangement have important effects on the galvanic corrosion of the three-metal coupled system. The corrosion current of the HAl77-2 increased with temperature indicating enhanced anode corrosion at higher temperature. In addition, the corrosion of HAl77-2 was more significant when the HAl77-2 wires were located in the middle of the coupled system than with the other two metal arrangement styles.

Specific features of implosion of metallized fiber arrays

Energy Technology Data Exchange (ETDEWEB)

Mitrofanov, K. N., E-mail: mitrofan@triniti.ru; Aleksandrov, V. V.; Gritsuk, A. N.; Grabovski, E. V.; Frolov, I. N.; Laukhin, Ya. N.; Breshkov, S. S. [Troitsk Institute for Innovation and Fusion Research (Russian Federation)

2017-02-15

Implosion of metallized fiber arrays was studied experimentally at the Angara-5-1 facility. The use of such arrays makes it possible to investigate the production and implosion dynamics of plasmas of various metals (such as tin, indium, and bismuth) that were previously unavailable for such studies. The plasma production rates m-dot (in μg/(cm{sup 2} ns)) for different metals were determined and quantitatively compared. Varying the thickness of the metal layer deposited on kapron fibers (the total linear mass of the metal coating being maintained at the level of 220 μg/cm), the current and velocity of the plasma precursor were studied as functions of the thickness of the metal coating. The strong difference in the rates of plasma production from the metal coating and kapron fibers results in the redistribution of the discharge current between the Z-pinch and the trailing fiber plasma. The outer boundary of the plasma produced from the metal coating is found to be stable against instabilities typical of the final stage of implosion of conventional wire arrays.

Pressure-induced polyamorphism in lanthanide-solute metallic glasses

Energy Technology Data Exchange (ETDEWEB)

Li, Liangliang; Li, Renfeng; Liu, Haozhe [Harbin Institute of Technology, Harbin (China); Center for High Pressure Science Technology Advanced Research, Changchun (China); Wang, Luhong [Harbin Institute of Technology, Harbin (China); Qu, Dongdong [School of Mechanical and Mining Engineering, The University of Queensland, Brisbane, QLD (Australia); Zhao, Haiyan [X-ray Science Division, Advanced Photon Source, Argonne National Laboratory, Argonne, IL (United States); Center for Advanced Energy Studies, University of Idaho, Idaho Falls, ID (United States); Chapman, Karena W.; Chupas, Peter J. [X-ray Science Division, Advanced Photon Source, Argonne National Laboratory, Argonne, IL (United States)

2017-06-15

The electronic structure inheritance of lanthanide-solvent atoms in lanthanide-based metallic glasses has been proposed. Is a polyamorphism possible in lanthanide-solute metallic glasses? So far, polyamorphic phase transitions in metallic glass containing lanthanide have been observed only in lanthanide-solvent metallic glasses. Here, a pressure-induced transition between two distinct amorphous states, accompanied by a 7% volume collapse at ambient pressure, was observed in La{sub 43.4}Pr{sub 18.6}Al{sub 14}Cu{sub 24} metallic glass, with low lanthanide content, by using in situ X-ray total scattering method. The transformation also indicated by changes in short range and medium range order. Thus, it is proposed that the lanthanide-solute metallic glasses also inherit 4f electronic transition from pure lanthanide element in polyamorphic transition. This discovery offers a supplement to research on lanthanide-based metallic glasses, which further provides a new perspective of the polyamorphic transformation in metallic glasses containing lanthanide element. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Cortical concentrations of metals and protein in the brain of two ...

African Journals Online (AJOL)

Metal pollution and exposure is an increasing global problem. One of the best ways to assess the impact of this problem on the brain is by using animals raised in such environments. As a prelude to this, the goat was used in this study to determine its normal metal and protein level in the brain. Ten metals and total crude ...

Structural basis for expanding the application of bioligand in metal bioremediation: A review.

Science.gov (United States)

Sharma, Virbala; Pant, Deepak

2018-03-01

Bioligands (BL) present in plant and microbes are primarily responsible for their use in metal decontamination. Both primary (proteins and amino acid) and secondary (proliferated) response in the form of BL is possible in plants and microbes toward metal bioremediation. Structure of these BL have specific requirement for preferential binding towards a particular metal in biomass. The aim of this review is to explore various templates from BL (as metal host) for the metal detoxification/decontamination and associated bioremediation. Mechanistic explanation for bioremediation may involve the various processes like: (i) electron transfer; (ii) translocation; and (iii) coordination number variation. HSAB (hard and soft acid and base) concept can act as guiding principle for many such processes. It is possible to investigate various structural homolog of BL (similar to secondary response in living stage) for the possible improvement in bioremediation process. Copyright © 2017 Elsevier Ltd. All rights reserved.

Metallated metal-organic frameworks

Energy Technology Data Exchange (ETDEWEB)

Bury, Wojciech; Farha, Omar K.; Hupp, Joseph T.; Mondloch, Joseph E.

2017-08-22

Porous metal-organic frameworks (MOFs) and metallated porous MOFs are provided. Also provided are methods of metallating porous MOFs using atomic layer deposition and methods of using the metallated MOFs as catalysts and in remediation applications.

Gas Metal Arc Welding. Welding Module 5. Instructor's Guide.

Science.gov (United States)

Missouri Univ., Columbia. Instructional Materials Lab.

This guide is intended to assist vocational educators in teaching an eight-unit module in gas metal arc welding. The module is part of a welding curriculum that has been designed to be totally integrated with Missouri's Vocational Instruction Management System. The following topics are covered in the module: safety and testing, gas metal arc…

Biogenic precipitation of manganese oxides and enrichment of heavy metals at acidic soil pH

Science.gov (United States)

Mayanna, Sathish; Peacock, Caroline L.; Schäffner, Franziska; Grawunder, Anja; Merten, Dirk; Kothe, Erika; Büchel, Georg

2014-05-01

The precipitation of biogenic Mn oxides at acidic pH is rarely reported and poorly understood, compared to biogenic Mn oxide precipitation at near neutral conditions. Here we identified and investigated the precipitation of biogenic Mn oxides in acidic soil, and studied their role in the retention of heavy metals, at the former uranium mining site of Ronneburg, Germany. The site is characterized by acidic pH, low carbon content and high heavy metal loads including rare earth elements. Specifically, the Mn oxides were present in layers identified by detailed soil profiling and within these layers pH varied from 4.7 to 5.1, Eh varied from 640 to 660 mV and there were enriched total metal contents for Ba, Ni, Co, Cd and Zn in addition to high Mn levels. Using electron microprobe analysis, synchrotron X-ray diffraction and X-ray absorption spectroscopy, we identified poorly crystalline birnessite (δ-MnO2) as the dominant Mn oxide in the Mn layers, present as coatings covering and cementing quartz grains. With geochemical modelling we found that the environmental conditions at the site were not favourable for chemical oxidation of Mn(II), and thus we performed 16S rDNA sequencing to isolate the bacterial strains present in the Mn layers. Bacterial phyla present in the Mn layers belonged to Firmicutes, Actinobacteria and Proteobacteria, and from these phyla we isolated six strains of Mn(II) oxidizing bacteria and confirmed their ability to oxidise Mn(II) in the laboratory. The biogenic Mn oxide layers act as a sink for metals and the bioavailability of these metals was much lower in the Mn layers than in adjacent layers, reflecting their preferential sorption to the biogenic Mn oxide. In this presentation we will report our findings, concluding that the formation of natural biogenic poorly crystalline birnessite can occur at acidic pH, resulting in the formation of a biogeochemical barrier which, in turn, can control the mobility and bioavailability of heavy metals in

Determination of diffusible and total hydrogen concentration in coated and uncoated steel

Energy Technology Data Exchange (ETDEWEB)

Mabho, Nonhlangabezo

2010-09-23

The new trend in the steel industry demands thin, flexible, high strength steels with low internal embrittlement. It is a well known fact that the atomic hydrogen which is picked up during production, fabrication and service embrittles the steel. This has led to an extensive research towards the improvement of the quality of metallic materials by focusing on total and diffusible hydrogen concentrations which are responsible for hydrogen embrittlement. Since the internal embrittlement cannot be foreseen, the concentrations of diffusible hydrogen work as indicators while the total hydrogen characterizes the absorbed quantities and quality of that particular product. To meet these requirements, the analytical chemistry methods which include the already existing carrier gas melt (fusion) extraction methods that use infrared and thermal conductivity for total hydrogen detection were applied. The newly constructed carrier gas thermal desorption mass spectroscopy was applied to monitor the diffusible concentration at specific temperatures and desorption rates of hydrogen which will contribute towards the quality of materials during service. The TDMS method also involved the characterization of the energy quantity (activation energy) required by hydrogen to be removed from traps of which irreversible traps are preferred because they enhance the stability of the product by inhibiting the mobility of hydrogen which is detrimental to the metallic structures. The instrumentation for TDMS is quite simple, compact, costs less and applicable to routine analysis. To determine total and diffusible hydrogen, the influence of the following processes: chemical and mechanical zinc coating removal, sample cleaning with organic solvents, conditions for hydrogen absorption by electrolytic hydrogen charging, conditions of hydrogen desorption by storing the sample at room temperature, solid CO{sub 2} and at temperatures of the drier was analysed. The contribution of steel alloys towards

Progress in vacuum metal extraction, refining and consolidation

International Nuclear Information System (INIS)

Sundaram, C.V.; Mukherjee, T.K.; Sharma, B.P.

1973-01-01

The unique achievements in the process metallurgy of rare metals in the past quarter century should largely be attributed to advances in vacuum technology. New standards for high purity, increasing demand for pure metals and alloys for established applications, and steady improvement in sophistication and capacity of vacuum furnaces have provided the stimulus for developing and expanding vacuum metal extraction processes, and also exploring totally new processes. The paper discusses the thermochemistry of vacuum metallurgy, carbothermic and metallothermic reduction reactions, consolidation and refining by vacuum arc melting, electron beam melting and high temperature high vacuum sintering, and ultrapurification, with special reference to the reactive and refractory metals of Group IV to VI. (author)

Uranium Metal Analysis via Selective Dissolution

Energy Technology Data Exchange (ETDEWEB)

Delegard, Calvin H.; Sinkov, Sergey I.; Schmidt, Andrew J.; Chenault, Jeffrey W.

2008-09-10

Uranium metal, which is present in sludge held in the Hanford Site K West Basin, can create hazardous hydrogen atmospheres during sludge handling, immobilization, or subsequent transport and storage operations by its oxidation/corrosion in water. A thorough knowledge of the uranium metal concentration in sludge therefore is essential to successful sludge management and waste process design. The goal of this work was to establish a rapid routine analytical method to determine uranium metal concentrations as low as 0.03 wt% in sludge even in the presence of up to 1000-fold higher total uranium concentrations (i.e., up to 30 wt% and more uranium) for samples to be taken during the upcoming sludge characterization campaign and in future analyses for sludge handling and processing. This report describes the experiments and results obtained in developing the selective dissolution technique to determine uranium metal concentration in K Basin sludge.

Electron scattering on metal clusters and fullerenes

International Nuclear Information System (INIS)

Solov'yov, A.V.

2001-01-01

This paper gives a survey of physical phenomena manifesting themselves in electron scattering on atomic clusters. The main emphasis is made on electron scattering on fullerenes and metal clusters, however some results are applicable to other types of clusters as well. This work is addressed to theoretical aspects of electron-cluster scattering, however some experimental results are also discussed. It is demonstrated that the electron diffraction plays important role in the formation of both elastic and inelastic electron scattering cross sections. It is elucidated the essential role of the multipole surface and volume plasmon excitations in the formation of electron energy loss spectra on clusters (differential and total, above and below ionization potential) as well as the total inelastic scattering cross sections. Particular attention is paid to the elucidation of the role of the polarization interaction in low energy electron-cluster collisions. This problem is considered for electron attachment to metallic clusters and the plasmon enhanced photon emission. Finally, mechanisms of electron excitation widths formation and relaxation of electron excitations in metal clusters and fullerenes are discussed. (authors)

The mechanism of metal nanoparticle formation in plants: limits on accumulation

Energy Technology Data Exchange (ETDEWEB)

Haverkamp, R. G., E-mail: r.haverkamp@massey.ac.nz; Marshall, A. T. [Massey University, School of Engineering and Advanced Technology (New Zealand)

2009-08-15

Metal nanoparticles have many potential technological applications. Biological routes to the synthesis of these particles have been proposed including production by vascular plants, known as phytoextraction. While many studies have looked at metal uptake by plants, particularly with regard to phytoremediation and hyperaccumulation, few have distinguished between metal deposition and metal salt accumulation. This work describes the uptake of AgNO{sub 3}, Na{sub 3}Ag(S{sub 2}O{sub 3}){sub 2}, and Ag(NH{sub 3}){sub 2}NO{sub 3} solutions by hydroponically grown Brassica juncea and the quantitative measurement of the conversion of these salts to silver metal nanoparticles. Using X-ray absorption near edge spectroscopy (XANES) to determine the metal speciation within the plants, combined with atomic absorption spectroscopy (AAS) for total Ag, the quantity of reduction of Ag{sup I} to Ag{sup 0} is reported. Transmission electron microscopy (TEM) showed Ag particles of 2-35 nm. The factors controlling the amount of silver accumulated are revealed. It is found that there is a limit on the amount of metal nanoparticles that may be deposited, of about 0.35 wt.% Ag on a dry plant basis, and that higher levels of silver are obtained only by the concentration of metal salts within the plant, not by deposition of metal. The limit on metal nanoparticle accumulation, across a range of metals, is proposed to be controlled by the total reducing capacity of the plant for the reduction potential of the metal species and limited to reactions occurring at an electrochemical potential greater than 0 V (verses the standard hydrogen electrode).

Optimization of IC/HPLC as a rapid analytical tool for characterization of total impurities in UO2

International Nuclear Information System (INIS)

Kelkar, A.G.; Kapoor, Y.S.; Mahanty, B.N.; Fulzele, A.K.; Mallik, G.K.

2007-01-01

Use of ion chromatography in the determination of metallic and non metallic impurities has been studied and observed to be very satisfactory. In the present paper the total time was monitored in all these experiments and compared with the conventional analytical techniques. (author)

Metallomics of two microorganisms relevant to heavy metal bioremediation reveal fundamental differences in metal assimilation and utilization

Energy Technology Data Exchange (ETDEWEB)

Lancaster, Andrew [Univ. of Georgia, Athens, GA (United States); Menon, Angeli [Univ. of Georgia, Athens, GA (United States); Scott, Israel [Univ. of Georgia, Athens, GA (United States); Poole, Farris [Univ. of Georgia, Athens, GA (United States); Vaccaro, Brian [Univ. of Georgia, Athens, GA (United States); Thorgersen, Michael P. [Univ. of Georgia, Athens, GA (United States); Geller, Jil [Lawrence Berkeley National Laboratory (LBNL); Hazen, Terry C. [Univ. of Tennessee, Knoxville, TN (United States); Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Hurt Jr., Richard Ashley [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Brown, Steven D. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Elias, Dwayne A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Adams, Michael W. W. [Univ. of Georgia, Athens, GA (United States)

2014-03-26

Although as many as half of all proteins are thought to require a metal cofactor, the metalloproteomes of microorganisms remain relatively unexplored. Microorganisms from different environments are likely to vary greatly in the metals that they assimilate, not just among the metals with well-characterized roles but also those lacking any known function. Herein we investigated the metal utilization of two microorganisms that were isolated from very similar environments and are of interest because of potential roles in the immobilization of heavy metals, such as uranium and chromium. The metals assimilated and their concentrations in the cytoplasm of Desulfovibrio vulgaris strain Hildenborough (DvH) and Enterobacter cloacae strain Hanford (EcH) varied dramatically, with a larger number of metals present in Enterobacter. For example, a total of 9 and 19 metals were assimilated into their cytoplasmic fractions, respectively, and DvH did not assimilate significant amounts of zinc or copper whereas EcH assimilated both. However, bioinformatic analysis of their genome sequences revealed a comparable number of predicted metalloproteins, 813 in DvH and 953 in EcH. These allowed some rationalization of the types of metal assimilated in some cases (Fe, Cu, Mo, W, V) but not in others (Zn, Nd, Ce, Pr, Dy, Hf and Th). It was also shown that U binds an unknown soluble protein in EcH but this incorporation was the result of extracellular U binding to cytoplasmic components after cell lysis.

[Eleven-Year Experience with Total Ankle Arthroplasty].

Science.gov (United States)

Popelka, S; Sosna, A; Vavřík, P; Jahoda, D; Barták, V; Landor, I

2016-01-01

PURPOSE OF THE STUDY Total joint replacement is one of the options in surgical treatment of advanced ankle arthritis. It allows the ankle to remain mobile but, unfortunately, it does not provide the same longevity as total knee or hip replacements. Therefore, decisions concerning the kind of treatment are very individual and depend on the clinical status and opinion of each patient. MATERIAL AND METHODS A total of 132 total ankle replacements were carried out in the period from 2004 to 2015. The prostheses used included the Ankle Evolutive System (AES) in 52 patients, Mobility Total Ankle System (DePuy) in 24 patients and, recently, Rebalance Total Ankle Replacement implant in 53 patients. Three patients allergic to metal received the Taric prosthesis. Revision arthroplasty using the Hintegra prosthesis was carried out in four patients. The outcome of arthroplasty was evaluated on the American Orthopaedic Foot and Ankle Society (AOFAS) scoring scale. Indications for total ankle arthroplasty included post-traumatic arthritis in 83 patients, rheumatoid arthritis in 37 and primary arthritis in 12 patients. There were 78 women and 54 men, with an average age of 55.6 years at the time of surgery. RESULTS The average follow-up was 6.1 years (1-11 years). The average AOFAS score of the whole group increased from 33.2 before surgery to 82.5 after it. The primary indication had an important role. Arthroplasty outcomes were poorer in patients with post-traumatic arthritis than in those with rheumatoid arthritis or primary arthritis. In patients with post-traumatic arthritis, the average AOFAS score rose to 78.6 due to restricted motion of the ankle, and some patients continued to have pain when walking. The average AOFAS score in a total of 49 patients who had rheumatoid arthritis or primary arthritis reached a value of 86.4. Post-operative complications were recorded in ten patients (7.6%) in whom part of the wound was healing by second intention. Ossification was also a

Complex Metal Hydrides for Hydrogen, Thermal and Electrochemical Energy Storage

DEFF Research Database (Denmark)

Moller, Kasper T.; Sheppard, Drew; Ravnsbaek, Dorthe B.

2017-01-01

Hydrogen has a very diverse chemistry and reacts with most other elements to form compounds, which have fascinating structures, compositions and properties. Complex metal hydrides are a rapidly expanding class of materials, approaching multi-functionality, in particular within the energy storage...... inspiration to solve the great challenge of our time: efficient conversion and large-scale storage of renewable energy....... field. This review illustrates that complex metal hydrides may store hydrogen in the solid state, act as novel battery materials, both as electrolytes and electrode materials, or store solar heat in a more efficient manner as compared to traditional heat storage materials. Furthermore, it is highlighted...

Unusual metal coordination chemistry from an amino-amide derivative of 4-nitrophenol, a surprising ligand

DEFF Research Database (Denmark)

McGinley, John; McKee, Vickie; Toftlund, Hans

2009-01-01

The simple ligand N-(2-aminoethyl)-2-hydroxy-5-nitrobenzamide () exhibits several coordination modes depending on the reaction conditions, acting as a zwitterion on its own or being ionic in the presence of acid and depending on the concentration of metal present in a reaction, it can coordinate...... to the metal in either a 1:1 or a 1:2 metal:ligand mode. Furthermore, the role of solvent plays an important role in these complexation reactions with both four and six coordinate copper complexes being obtained using water as solvent but only six coordinate copper complexes obtained using acetonitrile...

Heavy metal pollutants in surficial sediments from different coastal sites in Aden Governorate, Yemen

International Nuclear Information System (INIS)

Ali, Anis Ahmed; Baharoon Aqil Abdulrahman

2004-01-01

Concentrations of Gd, Pb, Zn, Cu, Ni, Co, Cr, Mn and Fe in surficial sediments (<63μm) from the shores in Aden Governorate were determined by atomic absorption spectrophotometry method. The obtained concentration data show significant regional variations concerning both the total and leachable metals in sediments. Total metal concentrations of Cd and Pb were greatest in sediments from labor Island; Cu, Cr, and Fe occurred in the highest levels in Bandar Fuqum sediments, while maximum levels of Mn, Co, and Ni were observed in sediments from Sahel Abyan and Fuqum. Labile, easily extractable species of metals such as Cd and Pb, are similar to their total concentrations, and additionally Cu, Zn, Cr, and Fe were found in the highest concentrations in sediments from labor Island. Sediments from Sahel Abyan and Khawr Bir Ahmed were characterized by a maximum accumulation of bioavailable species of Co and Mn, respectively. The linear regression slopes for metals correlated were <1, this explains the slow enrichment of these metals in the sediments, and attributes their geological nature. (author)

PENETAPAN KADAR FENOLIK TOTAL DAN FLAVONOID TOTAL EKSTRAK BERAS HITAM (Oryza sativa L DARI KALIMANTAN SELATAN

Directory of Open Access Journals (Sweden)

Anna Khumaira Sari

2017-10-01

Full Text Available The black rice contains anthocyanin compounds which are included in the flavonoids and phenolic compounds. Flavonoids contained in black rice are phenolic components that act as a preventive of hydroxyl and superoxide radicals by protecting membrane lipids against damaging oxidation reactions and phenol compounds also have bacteriocid, antimetic, antihelmintic, antiinflammatory, antimicrobial, anticancer and other degenerative diseases. The aim of this research were to measure total phenolic content and total flavonoid in ethanol extract of black rice (Oryza sativa L. Total phenol content were measured by Folin-Ciocalteu method with gallic acid mean while total flavonoid content were measured by colorimetry method using reagent AlCl3 10% and 5% acetic acid. There are seven variation samples of black rice obtained from seven different places in South Kalimantan. The result of this study, qualitative analysis showed that all samples positive contained flavonoids, alkaloids and tannins. The total phenol content of the seven samples was 100,58 ± 1,344; 91.14 ± 1.699; 96.50 ± 1.529; 77.64 ± 0.462; 81,16 ± 0,614; 112.47 ± 1.040; 81,50 ± 2,928 mgGAE/mg extract and the percent of total flavonoid content from seven samples was 8,53 ± 0,208%; 8.11 ± 0.343%; 7.69 ± 0.446%; 6.03 ± 0.227%; 4.97 ± 0.169%; 3.74 ± 0.210%; 5.02 ± 0.403%.

Evaluation of the air quality regarding total suspended particles and heavy metals (Pb, Cd, Ni, Cu, Cr) in the Hermosillo city, Sonora, Mexico, during a yearly period; Evaluacion de la calidad del aire respecto de particulas suspendidas totales y metales pesados (Pb, Cd, Ni, Cu, Cr) en la Ciudad de Hermosillo, Sonora, Mexico, durante un periodo anual

Energy Technology Data Exchange (ETDEWEB)

Cruz C, M. E.; Quintero N, M. [Universidad Autonoma de Baja California, Instituto de Ingenieria, Campus Mexicali, Calle de la Normal s/n, y Blvd. Benito Juarez, Col. Insurgentes Este, Mexicali, Baja California (Mexico); Gomez A, A.; Varela S, J., E-mail: martincruzcampas@hotmail.com [Universidad de Sonora, Departamento de Ingenieria Quimica y Metalurgia, Blvd. Rosales y Luis Ensina s/n, Edificio 5B, Col. Centro, 83000 Hermosillo, Sonora (Mexico)

2013-07-01

In the present study, the air quality of the city of Hermosillo, Sonora, Mexico was assessed considering total suspended particulates (tsp) and heavy metals (Pb, Cd, Ni, Cu, Cr) from June 2001 through May 2002 in three monitoring sites Centro (Mazon), Nor este (CESUES) and Noroeste (CBTIS). The filter-samples used for that purpose were provided by the Air Quality Evaluation and Improvement Program (PEMCA) of the municipality of Hermosillo. The sampling method was based on high volume sampling frequency set every 6 days with non-simultaneous sampling among the three sampling sites. Filters were dissolved for metal determination by acidic-extraction, and then analyzed by flame atomic absorption spectrophotometry. Results indicate that tsp concentrations at Centro and Noroeste sites were frequently higher than the maximum daily permissible level (260 {mu}g/m{sup 3}), while in the three sites the annual average was higher than the maximum annual permissible level (75 {mu}g/m{sup 3}) both established in the standard NOM-024-Ssa-1993 (Ssa 1994a). According to the Air Quality Standard Index (US EPA 1992a), used in Mexico by Air Quality Metropolitan Index (IMECA) the results indicate that the air quality in the city of Hermosillo regarding tsp was placed between no satisfactory and poor. In regard to heavy metals (Pb, Cd, Ni, Cu, Cr), concentrations detected were below the maximum permissible levels and/or criteria taking into account the standard NOM-026-Ssa-1993 (Ssa 1994b), the Who criterion (2000), the European Union criterion (Cec 2003), and the European Environmental Agency criteria (EEA 2004). Such findings would mean that airborne metals are of no concern; however, air quality is still classified as no satisfactory due to high particulate matter concentrations. Keeping air quality parameters monitoring is recommended in order to get extensive data for use in risk studies of air quality and health (morbidity/mortality), as well as topographic conditions

Process Stability of Ultrasonic-Wave-Assisted Gas Metal Arc Welding

Science.gov (United States)

Fan, Chenglei; Xie, Weifeng; Yang, Chunli; Lin, Sanbao; Fan, Yangyang

2017-10-01

As a newly developed arc welding method, ultrasonic-wave-assisted arc welding successfully introduced power ultrasound into the arc and weld pool, during which the ultrasonic acts on the top of the arc in the coaxial alignment direction. The advanced process for molten metals can be realized by using an additional ultrasonic field. Compared with the conventional gas metal arc welding (GMAW), the welding arc is compressed, the droplet size is decreased, and the droplet transfer frequency is increased significantly in ultrasonic-wave-assisted GMAW (U-GMAW). However, the stability of the metal transfer has deep influence on the welding quality equally, and the ultrasonic wave effect on the stability of the metal transfer is a phenomenon that is not completely understood. In this article, the stabilities of the short-circuiting transfer process and globular transfer process are studied systematically, and the effect of ultrasonic wave on the metal transfer is analyzed further. The transfer frequency and process stability of the U-GMAW process are much higher than those of the conventional GMAW. Analytical results show that the additional ultrasonic wave is helpful for improving welding stability.

Speciation of Aquatic Heavy Metals in Humic Substances by$^{111m}$Cd/$^{199m}$Hg-TDPAC

CERN Multimedia

2002-01-01

Humic substances are ubiquitous in waters and soils and act as complexing agents for different heavy metals, e.g. Cd, Hg. Toxicity, reactivity, fixation and migration are therefore strongly influenced by the interactions between heavy metals and humic substances. Humic substances derive from postmortal materials such as rotten plants, have dark colours and usually a molecular weight between 500 and 10~000 Dalton. Complex formation studies with different heavy metal ions indicate at least two different kinds of metal sites. Usually, these studies are restricted to heavy metal concentrations 2 to 3 orders of magnitude higher than the natural heavy metal abundance (i.e. 10$^{-10}$ molar). This serious limitation can be overcome by the use of suitable radiosotope techniques capable of metal speciation at extreme sensitivity levels such as TDPAC (Time Differential Perturbed Angular Correlation of~$\\gamma$-rays). Thus, we studied the interaction of heavy metals with humic substances by monitoring the nuclear quadru...

Potentially toxic metals in ombrotrophic peat along a 400 km English-Scottish transect

Energy Technology Data Exchange (ETDEWEB)

Smith, E.J. [Centre for Ecology and Hydrology (Lancaster), Lancaster Environment Centre, Bailrigg, Lancaster LA1 4AP (United Kingdom); Hughes, S. [Centre for Ecology and Hydrology (Bangor), Deiniol Road, Bangor, Gwynedd LL57 2UP (United Kingdom); Lawlor, A.J. [Centre for Ecology and Hydrology (Lancaster), Lancaster Environment Centre, Bailrigg, Lancaster LA1 4AP (United Kingdom); Lofts, S. [Centre for Ecology and Hydrology (Lancaster), Lancaster Environment Centre, Bailrigg, Lancaster LA1 4AP (United Kingdom); Simon, B.M. [Centre for Ecology and Hydrology (Lancaster), Lancaster Environment Centre, Bailrigg, Lancaster LA1 4AP (United Kingdom); Stevens, P.A. [Centre for Ecology and Hydrology (Bangor), Deiniol Road, Bangor, Gwynedd LL57 2UP (United Kingdom); Stidson, R.T. [Centre for Ecology and Hydrology (Lancaster), Lancaster Environment Centre, Bailrigg, Lancaster LA1 4AP (United Kingdom); Tipping, E. [Centre for Ecology and Hydrology (Lancaster), Lancaster Environment Centre, Bailrigg, Lancaster LA1 4AP (United Kingdom)]. E-mail: et@ceh.ac.uk; Vincent, C.D. [Centre for Ecology and Hydrology (Lancaster), Lancaster Environment Centre, Bailrigg, Lancaster LA1 4AP (United Kingdom)

2005-07-15

Four samples of ombrotrophic peat were collected from each of 10 upland locations in a transect from the southern Pennines to the Highland Boundary Fault, a total distance of ca. 400 km. Bulk compositions and other properties were determined. Total contents of Al and heavy metals (Ni, Cu, Zn, Cd, Pb) were determined following digestion with hydrofluoric acid, and concentrations of metals extractable with dilute nitric acid were also measured. Supernatants obtained from aqueous extractions of the peat samples were analysed for pH, major cations and anions, dissolved organic carbon and dissolved metals, and concentrations of free metal ions (Al{sup 3+}, Ni{sup 2+}, etc.) were estimated by applying a chemical speciation model. Both total and HNO{sub 3}-extractable metal concentrations varied along the transect, the highest values being found at locations close to industrial and former mining areas. The HNO{sub 3}-extractable soil metal contents of Ni, Cu and Cd were appreciably lower than lowest-observed-effect-concentrations (LOEC) for toxicity towards microorganisms in acid, organic rich soils. However, the contents of Zn at two locations, and of Pb at five locations exceeded LOECs, suggesting that they may be exerting toxic effects in the peats. Soil solution concentrations of free heavy metal ions (Cu{sup 2+}, Zn{sup 2+}, Cd{sup 2+}, Pb{sup 2+}) were substantially lower than LOECs for toxicity towards vascular plants, whereas concentrations of Al{sup 3+} were near to toxic levels at two locations. - P eat metal contents depend upon proximity to industrial and mining areas; the metals may be exerting toxic effects in some places.

The size effect in metal cutting

Indian Academy of Sciences (India)

Since the shear stress and strain in metal cutting is unusually high, ... thus joining the transport of dislocations in accounting for the total slip of the shear plane. ... shear plane, and the important role compressive stress plays on the shear plane.

Development of a field test method for total suspended solids analysis.

Science.gov (United States)

2013-11-01

Total suspended solids (TSS) are all particles in water that will not pass through a glass fiber filter with a pore size less : than 2 m, including sediments, algae, nutrients, and metals. TSS is an important water quality parameter because of its ...

Assessment of biotic response to heavy metal contamination in Avicennia marina mangrove ecosystems in Sydney Estuary, Australia.

Science.gov (United States)

Nath, Bibhash; Chaudhuri, Punarbasu; Birch, Gavin

2014-09-01

Mangrove forests act as a natural filter of land-derived wastewaters along industrialized tropical and sub-tropical coastlines and assist in maintaining a healthy living condition for marine ecosystems. Currently, these intertidal communities are under serious threat from heavy metal contamination induced by human activity associated with rapid urbanization and industrialization. Studies on the biotic responses of these plants to heavy metal contamination are of great significance in estuary management and maintaining coastal ecosystem health. The main objective of the present investigation was to assess the biotic response in Avicennia marina ecosystems to heavy metal contamination through the determination of metal concentrations in leaves, fine nutritive roots and underlying sediments collected in fifteen locations across Sydney Estuary (Australia). Metal concentrations (especially Cu, Pb and Zn) in the underlying sediments of A. marina were enriched to a level (based on Interim Sediment Quality Guidelines) at which adverse biological effects to flora could occasionally occur. Metals accumulated in fine nutritive roots greater than underlying sediments, however, only minor translocation of these metals to A. marina leaves was observed (mean translocation factors, TFs, for all elements micro-nutrients, Cu, Ni, Mn and Zn) were greater than non-essential elements (As, Cd, Co, Cr and Pb), suggesting that A. marina mangroves of this estuary selectively excluded non-essential elements, while regulating essential elements and limiting toxicity to plants. This study supports the notion that A. marina mangroves act as a phytostabilizer in this highly modified estuary thereby protecting the aquatic ecosystem from point or non-point sources of heavy metal contamination. Copyright © 2014 Elsevier Inc. All rights reserved.

Trentepohlia algae biofilms as bioindicator of atmospheric metal pollution.

Science.gov (United States)

García-Florentino, Cristina; Maguregui, Maite; Morillas, Héctor; Marcaida, Iker; Salcedo, Isabel; Madariaga, Juan Manuel

2018-06-01

In this work, a reddish biocolonization composed mainly by Trentepohlia algae affecting a synthetic building material from a modern building from the 90s located in the Bizkaia Science and Technology Park (Zamudio, North of Spain) was characterized and its ability to accumulate metals coming from the surrounding atmosphere was evaluated. To asses if these biofilms can act as bioindicators of the surrounding metal pollution, a fast non-invasive in situ methodology based on the use of hand-held energy dispersive X-ray fluorescence (HH-ED-XRF) was used. In order to corroborate the in situ obtained conclusions, some fragments from the affected material were taken to analyze the metal distribution by means of micro-energy dispersive X-ray fluorescence spectroscopy (μ-ED-XRF) and to confirm the presence of metal particles deposited on it using Scanning Electron Microscopy coupled to an Energy Dispersive Spectrometer (SEM-EDS). In order to confirm if Trentepohlia algae biofilms growing on the surface of building materials could be a fast way to in situ provide information about the surrounding metal pollution, a second Trentepohlia algae biofilm growing on a different kind of material (sandstone) was analyzed from an older historical building, La Galea Fortress (Getxo, North of Spain). Copyright © 2018. Published by Elsevier B.V.

Synthesis, spectroscopic, biological activity and thermal characterization of ceftazidime with transition metals

Science.gov (United States)

Masoud, Mamdouh S.; Ali, Alaa E.; Elasala, Gehan S.; Kolkaila, Sherif A.

2018-03-01

Synthesis, physicochemical characterization and thermal analysis of ceftazidime complexes with transition metals (Cr(III), Mn(II), Fe(III), Co(II), Ni(II), Cu(II), Zn(II), Cd(II) and Hg(II)) were discussed. It's obtained that ceftazidime act as bidentate ligand. From magnetic measurement and spectral data, octahedral structures were proposed for all complexes except for cobalt, nickel and mercury had tetrahedral structural. Hyper chemistry program confirmed binding sites of ceftazidime. Ceftazidime complexes show higher activity than ceftazidime for some strains. From TG and DTA curves the thermal decomposition mechanisms of ceftazidime and their metal complexes were suggested. The thermal decomposition of the complexes ended with the formation of metal oxides as a final product except in case of Hg complex.

Heavy metals in edible seaweeds commercialised for human consumption

Science.gov (United States)

Besada, Victoria; Andrade, José Manuel; Schultze, Fernando; González, Juan José

2009-01-01

Though seaweed consumption is growing steadily across Europe, relatively few studies have reported on the quantities of heavy metals they contain and/or their potential effects on the population's health. This study focuses on the first topic and analyses the concentrations of six typical heavy metals (Cd, Pb, Hg, Cu, Zn, total As and inorganic As) in 52 samples from 11 algae-based products commercialised in Spain for direct human consumption ( Gelidium spp.; Eisenia bicyclis; Himanthalia elongata; Hizikia fusiforme; Laminaria spp.; Ulva rigida; Chondrus crispus; Porphyra umbilicales and Undaria pinnatifida). Samples were ground, homogenised and quantified by atomic absorption spectrometry (Cu and Zn by flame AAS; Cd, Pb and total As by electrothermal AAS; total mercury by the cold vapour technique; and inorganic As by flame-hydride generation). Accuracy was assessed by participation in periodic QUASIMEME (Quality Assurance of Information in Marine Environmental Monitoring in Europe) and IAEA (International Atomic Energy Agency) intercalibration exercises. To detect any objective differences existing between the seaweeds' metal concentrations, univariate and multivariate studies (principal component analysis, cluster analysis and linear discriminant analysis) were performed. It is concluded that the Hizikia fusiforme samples contained the highest values of total and inorganic As and that most Cd concentrations exceeded the French Legislation. The two harvesting areas (Atlantic and Pacific oceans) were differentiated using both univariate studies (for Cu, total As, Hg and Zn) and a multivariate discriminant function (which includes Zn, Cu and Pb).

Decontamination of metals and polycyclic aromatic hydrocarbons from slag-polluted soil.

Science.gov (United States)

Bisone, Sara; Mercier, Guy; Blais, Jean-François

2013-01-01

Metallurgy is an industrial activity that is one of the largest contributors to soil contamination by metals. This contamination is often associated with organic compound contamination; however, little research has been aimed at the development of simultaneous processes for decontamination as opposed to treatments to heavy metals or organic compounds alone. This paper presents an efficient process to decontaminate the soils polluted with smelting by-products rich in Cu, Zn and polycyclic aromatic hydrocarbons (PAHs). A simultaneous treatment for metals and PAHs was also tested. The process is mainly based on physical techniques, such as crushing, gravimetric separation and attrition. For the finest particle size fractions, an acid extraction with H2SO4 was used to remove metals. The PAH removal was enhanced by adding surfactant during attrition. The total metal removals varied from 49% to 73% for Cu and from 43% to 63% for Zn, whereas a removal yield of 92% was measured for total PAHs. Finally, a technical-economic evaluation was done for the two processes tested.

Characterization of heavy metal desorption from road-deposited sediment under acid rain scenarios.

Science.gov (United States)

Zhao, Bo; Liu, An; Wu, Guangxue; Li, Dunzhu; Guan, Yuntao

2017-01-01

Road-deposited sediments (RDS) on urban impervious surfaces are important carriers of heavy metals. Dissolved heavy metals that come from RDS influenced by acid rain, are more harmful to urban receiving water than particulate parts. RDS and its associated heavy metals were investigated at typical functional areas, including industrial, commercial and residential sites, in Guangdong, Southern China, which was an acid rain sensitive area. Total and dissolved heavy metals in five particle size fractions were analyzed using a shaking method under acid rain scenarios. Investigated heavy metals showed no difference in the proportion of dissolved fraction in the solution under different acid rain pHs above 3.0, regardless of land use. Dissolved loading of heavy metals related to organic carbon content were different in runoff from main traffic roads of three land use types. Coarse particles (>150μm) that could be efficiently removed by conventional street sweepers, accounted for 55.1%-47.1% of the total dissolved metal loading in runoff with pH3.0-5.6. The obtained findings provided a significant scientific basis to understand heavy metal release and influence of RDS grain-size distribution and land use in dissolved heavy metal pollution affected by acid rain. Copyright © 2016. Published by Elsevier B.V.

Toxic metals in children's toys and jewelry: Coupling bioaccessibility with risk assessment

International Nuclear Information System (INIS)

Cui, Xin-Yi; Li, Shi-Wei; Zhang, Shu-Jun; Fan, Ying-Ying; Ma, Lena Q.

2015-01-01

A total of 45 children's toys and jewelry were tested for total and bioaccessible metal concentrations. Total As, Cd, Sb, Cr, Ni, and Pb concentrations were 0.22–19, 0.01–139, 0.1–189, 0.06–846, 0.14–2894 and 0.08–860,000 mg kg −1 . Metallic products had the highest concentrations, with 3–7 out of 13 samples exceeding the European Union safety limit for Cd, Pb, Cr, or Ni. However, assessment based on hazard index >1 and bioaccessible metal showed different trends. Under saliva mobilization or gastric ingestion, 11 out of 45 samples showed HI >1 for As, Cd, Sb, Cr, or Ni. Pb with the highest total concentration showed HI <1 for all samples while Ni showed the most hazard with HI up to 113. Our data suggest the importance of using bioaccessibility to evaluate health hazard of metals in children's toys and jewelry, and besides Pb and Cd, As, Ni, Cr, and Sb in children's products also deserve attention. - Highlights: • Contamination of toxic metals in children's toys and jewelry (TJ) were studied. • Metals including Pb, Cd, Cr, and Ni in some TJ exceeded the EU safety limits. • Hazard index of TJ was assessed based on bioaccessible metals via saliva mobilization and oral ingestion. • Hazard index was >> 1 for Ni, and unacceptable for As, Cd, Cr, and Sb in some TJ. - Assessment of health hazard of children's toys and jewelry based on bioaccessible metals suggested that besides Pb and Cd, As, Ni, Cr, and Sb in children's products deserve attention

Molecular and ionic mimicry and the transport of toxic metals

Science.gov (United States)

Bridges, Christy C.; Zalups, Rudolfs K.

2008-01-01

Despite many scientific advances, human exposure to, and intoxication by, toxic metal species continues to occur. Surprisingly, little is understood about the mechanisms by which certain metals and metal-containing species gain entry into target cells. Since there do not appear to be transporters designed specifically for the entry of most toxic metal species into mammalian cells, it has been postulated that some of these metals gain entry into target cells, through the mechanisms of ionic and/or molecular mimicry, at the site of transporters of essential elements and/or molecules. The primary purpose of this review is to discuss the transport of selective toxic metals in target organs and provide evidence supporting a role of ionic and/or molecular mimicry. In the context of this review, molecular mimicry refers to the ability of a metal ion to bond to an endogenous organic molecule to form an organic metal species that acts as a functional or structural mimic of essential molecules at the sites of transporters of those molecules. Ionic mimicry refers to the ability of a cationic form of a toxic metal to mimic an essential element or cationic species of an element at the site of a transporter of that element. Molecular and ionic mimics can also be sub-classified as structural or functional mimics. This review will present the established and putative roles of molecular and ionic mimicry in the transport of mercury, cadmium, lead, arsenic, selenium, and selected oxyanions in target organs and tissues. PMID:15845419

Molecular and ionic mimicry and the transport of toxic metals

International Nuclear Information System (INIS)

Bridges, Christy C.; Zalups, Rudolfs K.

2005-01-01

Despite many scientific advances, human exposure to, and intoxication by, toxic metal species continues to occur. Surprisingly, little is understood about the mechanisms by which certain metals and metal-containing species gain entry into target cells. Since there do not appear to be transporters designed specifically for the entry of most toxic metal species into mammalian cells, it has been postulated that some of these metals gain entry into target cells, through the mechanisms of ionic and/or molecular mimicry, at the site of transporters of essential elements and/or molecules. The primary purpose of this review is to discuss the transport of selective toxic metals in target organs and provide evidence supporting a role of ionic and/or molecular mimicry. In the context of this review, molecular mimicry refers to the ability of a metal ion to bond to an endogenous organic molecule to form an organic metal species that acts as a functional or structural mimic of essential molecules at the sites of transporters of those molecules. Ionic mimicry refers to the ability of a cationic form of a toxic metal to mimic an essential element or cationic species of an element at the site of a transporter of that element. Molecular and ionic mimics can also be sub-classified as structural or functional mimics. This review will present the established and putative roles of molecular and ionic mimicry in the transport of mercury, cadmium, lead, arsenic, selenium, and selected oxyanions in target organs and tissues

Effect of carbon ion implantation on the tribology of metal-on-metal bearings for artificial joints

Directory of Open Access Journals (Sweden)

Koseki H

2017-05-01

Full Text Available Hironobu Koseki,1 Masato Tomita,2 Akihiko Yonekura,2 Takashi Higuchi,1 Sinya Sunagawa,2 Koumei Baba,3,4 Makoto Osaki2 1Department of Locomotive Rehabilitation Science, Unit of Rehabilitation Sciences, 2Department of Orthopedic Surgery, Nagasaki University Graduate School of Biomedical Sciences, Sakamoto, Nagasaki, Japan; 3Industrial Technology Center of Nagasaki, Ikeda, Omura, Nagasaki, Japan; 4Affiliated Division, Nagasaki University School of Engineering, Bunkyo, Nagasaki, Japan Abstract: Metal-on-metal (MoM bearings have become popular due to a major advantage over metal-on-polymer bearings for total hip arthroplasty in that the larger femoral head and hydrodynamic lubrication of the former reduce the rate of wear. However, concerns remain regarding adverse reactions to metal debris including metallosis caused by metal wear generated at the taper-head interface and another modular junction. Our group has hypothesized that carbon ion implantation (CII may improve metal wear properties. The purpose of this study was to investigate the wear properties and friction coefficients of CII surfaces with an aim to ultimately apply these surfaces to MoM bearings in artificial joints. CII was applied to cobalt-chromium-molybdenum (Co-Cr-Mo alloy substrates by plasma source ion implantation. The substrates were characterized using scanning electron microscopy and a 3D measuring laser microscope. Sliding contact tests were performed with a simple geometry pin-on-plate wear tester at a load of 2.5 N, a calculated contact pressure of 38.5 MPa (max: 57.8 MPa, a reciprocating velocity of 30 mm/s, a stroke length of 60 mm, and a reciprocating cycle count of 172,800 cycles. The surfaces of the CII substrates were generally featureless with a smooth surface topography at the same level as untreated Co-Cr-Mo alloy. Compared to the untreated Co-Cr-Mo alloy, the CII-treated bearings had lower friction coefficients, higher resistance to catastrophic damage, and

The behaviour of ashes and heavy metals during the co-combustion of sewage sludges in a fluidised bed

Energy Technology Data Exchange (ETDEWEB)

Lopes, M.H.; Abelha, P.; Lapa, N.; Oliveira, J.S.; Cabrita, I.; Gulyurtlu, I. [INETI, Lisbon (Portugal)

2003-07-01

Co-combustion tests of dry sewage sludges with coal were performed in a pilot bubbling FBC with the aim of characterizating the ashes and determining the behaviour of heavy metals in the process. The tests showed compliance with the regulatory levels as far as heavy metal emissions were concerned. The bottom ashes, which accounted for about 70% of the total ash production, were obtained in a granular form, with diameters ranging from 0.5 to 4 mm. The heavy metals were distributed in ashes obtained from different locations of the installation and their concentrations were found to vary depending on the location of capture. The increase in heavy metals content in bottom ashes was not found to lead to higher leachability and ecotoxicity compared to sewage sludges. Mercury suffered vaporisation inside the reactor, thus leaving bottom ashes free of contamination by it. However, there was observed a strong retention of mercury in cyclone ashes due to the presence of unburned carbon which probably acted as an adsorbent. The effluent mercury was also found to be mostly associated with the particulate fraction, being less than 20% emitted in gaseous forms. The results suggested that the combustion of the sewage sludge could successfully be carried out and the amount of unburned carbon leaving the combustor but captured in cyclone was large enough to ensure substantial retention of mercury at low temperatures, hence could contribute to an improvement of the mercury release which still remains an issue of great concern to resolve during combustion of waste materials.

The behaviour of ashes and heavy metals during the co-combustion of sewage sludges in a fluidised bed.

Science.gov (United States)

Helena Lopes, M; Abelha, P; Lapa, N; Oliveira, J S; Cabrita, I; Gulyurtlu, I

2003-01-01

Co-combustion tests of dry sewage sludges with coal were performed in a pilot bubbling FBC aiming at the characterization of ashes and determining the behaviour of heavy metals in the process. The tests showed compliance with the regulatory levels as far as heavy metal emissions were concerned. The bottom ashes, which accounted for about 70% of the total ash production, were obtained in a granular form, with diameters ranging from 0.5 to 4 mm. The heavy metals were distributed in ashes obtained from different locations of the installation and their concentrations were found to vary depending on the location of capture. The increase in heavy metals content in bottom ashes was not found to lead to higher leachability and ecotoxicity compared to sewage sludges, suggesting that there could be opportunities for their further use. Mercury suffered vaporisation inside the reactor, thus leaving bottom ashes free of contamination by it. However, there was observed a strong retention of mercury in cyclone ashes due to the presence of unburned carbon which probably acted as an adsorbent. The effluent mercury was also found to be mostly associated with the particulate fraction, being less than 20% emitted in gaseous forms. The results suggested that the combustion of the sewage sludge could successfully be carried out and the amount of unburned carbon leaving the combustor but captured in cyclone was large enough to ensure substantial retention of mercury at low temperatures, hence could contribute to an improvement of the mercury release which still remains an issue of great concern to resolve during combustion of waste materials.

The behaviour of ashes and heavy metals during the co-combustion of sewage sludges in a fluidised bed

International Nuclear Information System (INIS)

Helena Lopes, M.; Abelha, P.; Lapa, N.; Oliveira, J.S.; Cabrita, I.; Gulyurtlu, I.

2003-01-01

Co-combustion tests of dry sewage sludges with coal were performed in a pilot bubbling FBC aiming at the characterization of ashes and determining the behaviour of heavy metals in the process. The tests showed compliance with the regulatory levels as far as heavy metal emissions were concerned. The bottom ashes, which accounted for about 70% of the total ash production, were obtained in a granular form, with diameters ranging from 0.5 to 4 mm. The heavy metals were distributed in ashes obtained from different locations of the installation and their concentrations were found to vary depending on the location of capture. The increase in heavy metals content in bottom ashes was not found to lead to higher leachability and ecotoxicity compared to sewage sludges, suggesting that there could be opportunities for their further use. Mercury suffered vaporisation inside the reactor, thus leaving bottom ashes free of contamination by it. However, there was observed a strong retention of mercury in cyclone ashes due to the presence of unburned carbon which probably acted as an adsorbent. The effluent mercury was also found to be mostly associated with the particulate fraction, being less than 20% emitted in gaseous forms. The results suggested that the combustion of the sewage sludge could successfully be carried out and the amount of unburned carbon leaving the combustor but captured in cyclone was large enough to ensure substantial retention of mercury at low temperatures, hence could contribute to an improvement of the mercury release which still remains an issue of great concern to resolve during combustion of waste materials

Differentially Fed Metal Frame Antenna With Common Mode Suppression for Biomedical Smartband Applications

Science.gov (United States)

Xu, Li-Jie; Duan, Zhu

2018-04-01

This paper proposes a differentially fed metal frame antenna for biomedical smartband applications. It occupies a planar area of 40 × 20 mm, operating at 2.45-GHz industrial, scientific, and medical band. The proposed antenna is composed of an external metal frame and an internal metal box acting as ground for electronics. Through a differential feeding to two copper strips located between the metal frame and the metal box, a rectangular ring slot is excited with common mode suppression capability. The antenna prototype is designed in free space, and then adapted to on-body scenario for both repeater and transmitter cases. Additionally, the proposed differential feeding is modified to the traditional single port, demonstrating the half-size miniaturization technique. Finally, the simulated results are verified by measurement. The proposed antenna's simple structure and satisfactory performance makes it a perfect candidate for future medical smartband applications, monitoring the physiological parameters of humans for health-care purposes.

Improved description of metal oxide stability

DEFF Research Database (Denmark)

Jauho, Thomas Stenbæk; Olsen, Thomas; Bligaard, Thomas

2015-01-01

The renormalized adiabatic PBE (rAPBE) method has recently been shown to comprise a significant improvement over the random phase approximation (RPA) for total energy calculations of simple solids and molecules. Here we consider the formation energies of 19 group I and II metal oxides and a few...... transition-metal oxides. The mean absolute error relative to experiments is 0.21 eV and 0.38 eV per oxygen atom for rAPBE and RPA, respectively, and thus the rAPBE method greatly improves the description of metal-oxygen bonds across a wide range of oxides. The failure of the RPA can be partly attributed...... to the lack of error cancellation between the correlation energy of the oxide on the one hand and the bulk metal and oxygen molecule on the other hand, which are all separately predicted much too negative by the RPA. We ascribe the improved performance of the rAPBE to its significantly better description...

Structurally triggered metal-insulator transition in rare-earth nickelates.

Science.gov (United States)

Mercy, Alain; Bieder, Jordan; Íñiguez, Jorge; Ghosez, Philippe

2017-11-22

Rare-earth nickelates form an intriguing series of correlated perovskite oxides. Apart from LaNiO 3 , they exhibit on cooling a sharp metal-insulator electronic phase transition, a concurrent structural phase transition, and a magnetic phase transition toward an unusual antiferromagnetic spin order. Appealing for various applications, full exploitation of these compounds is still hampered by the lack of global understanding of the interplay between their electronic, structural, and magnetic properties. Here we show from first-principles calculations that the metal-insulator transition of nickelates arises from the softening of an oxygen-breathing distortion, structurally triggered by oxygen-octahedra rotation motions. The origin of such a rare triggered mechanism is traced back in their electronic and magnetic properties, providing a united picture. We further develop a Landau model accounting for the metal-insulator transition evolution in terms of the rare-earth cations and rationalizing how to tune this transition by acting on oxygen rotation motions.

Globally sustainable manganese metal production and use.

Science.gov (United States)

Hagelstein, Karen

2009-09-01

The "cradle to grave" concept of managing chemicals and wastes has been a descriptive analogy of proper environmental stewardship since the 1970s. The concept incorporates environmentally sustainable product choices-such as metal alloys utilized steel products which civilization is dependent upon. Manganese consumption is related to the increasing production of raw steel and upgrading ferroalloys. Nonferrous applications of manganese include production of dry-cell batteries, plant fertilizer components, animal feed and colorant for bricks. The manganese ore (high grade 35% manganese) production world wide is about 6 million ton/year and electrolytic manganese metal demand is about 0.7 million ton/year. The total manganese demand is consumed globally by industries including construction (23%), machinery (14%), and transportation (11%). Manganese is recycled within scrap of iron and steel, a small amount is recycled within aluminum used beverage cans. Recycling rate is 37% and efficiency is estimated as 53% [Roskill Metals and Minerals Reports, January 13, 2005. Manganese Report: rapid rise in output caused by Chinese crude steel production. Available from: http://www.roskill.com/reports/manganese.]. Environmentally sustainable management choices include identifying raw material chemistry, utilizing clean production processes, minimizing waste generation, recycling materials, controlling occupational exposures, and collecting representative environmental data. This paper will discuss two electrolytically produced manganese metals, the metal production differences, and environmental impacts cited to date. The two electrolytic manganese processes differ due to the addition of sulfur dioxide or selenium dioxide. Adverse environmental impacts due to use of selenium dioxide methodology include increased water consumption and order of magnitude greater solid waste generation per ton of metal processed. The use of high grade manganese ores in the electrolytic process also

Effective High-Frequency Permeability of Compacted Metal Powders

Science.gov (United States)

Volkovskaya, I. I.; Semenov, V. E.; Rybakov, K. I.

2018-03-01

We propose a model for determination of the effective complex permeability of compacted metal-powder media. It is based on the equality of the magnetic moment in a given volume of the media with the desired effective permeability to the total magnetic moment of metal particles in the external high-frequency magnetic field, which arises due to excitation of electric eddy currents in the particles. Calculations within the framework of the proposed model allow us to refine the values of the real and imaginary components of the permeability of metal powder compacts in the microwave band. The conditions of applicability of the proposed model are formulated, and their fulfillment is verified for metal powder compacts in the microwave and millimeter wavelength bands.

Awareness of Consumer Protection Act among dental health professionals in dental schools of Ghaziabad, India.

Science.gov (United States)

Prasad, Sumanth; Menon, Ipseeta; Dhingra, Chandan; Anand, Richa

2013-12-01

The study aimed to assess the awareness of the Consumer Protection Act among dental health professionals in dental schools of Ghaziabad, India. A cross-sectional questionnaire survey was carried out on dental health professionals in dental schools of Ghaziabad, India. A total of 348 dental health professionals (170 males and 178 females) were surveyed, out of which 116 were MDS faculty, 45 were BDS faculty and 187 were pursuing post graduation. The questionnaire comprised of 24 questions about the awareness of consumer protection act. Statistical analysis was done using Chi-square test, student's t test and ANOVA. A total of 84.8% (n=295) reported to be aware of consumer protection act. Amongst them, MDS faculty showed more awareness as compared to BDS faculty and those pursuing post-graduation. Considering the present scenario, MDS faculty dental professionals have more awareness of consumer protection act compared to other dental professionals. So, we must upgrade our knowledge on consumer protection act at all levels of our profession and change our attitude by inculcating a practice to spread the message of consumer protection act for delivering quality dental care.

Metal recycling experience at Los Alamos National Laboratory. Reuse, release, and recycle of metals from radiological control areas

International Nuclear Information System (INIS)

Gogol, S.

1997-01-01

Approximately 15% of the Low-Level Waste (LLW) produced at Los Alamos consists of scrap metal equipment and materials. The majority of this material is produced by decommissioning and the modification of existing facilities. To reduce this waste stream, Department of Energy Headquarters, EM-77 Office, sponsored the Reuse, Recycle, and Release of Metals from Radiological Control Areas High Return on Investment (ROI) Project to implement recycle, reuse, and release of scrap metal at the laboratory. The goal of this project was to develop cost effective alternatives to LLW disposal of scrap metal and to avoid the disposal of 2,400 m 3 of scrap metal. The ROI for this project was estimated at 948%. The ROI project was funded in March 1996 and is scheduled for completion by October 1997. At completion, a total of 2,400 m 3 of LLW avoidance will have been accomplished and a facility to continue recycling activities will be operational. This paper will present the approach used to develop effective alternatives for scrap metal at Los Alamos and then discuss the tasks identified in the approach in detail. Current scrap metal inventory, waste projections, alternatives to LLW disposal, regulatory guidance, and efforts to institutionalize the alternatives to LLW disposal will be discussed in detail

Metal accumulation and evaluation of effects in a freshwater turtle.

Science.gov (United States)

Yu, Shuangying; Halbrook, Richard S; Sparling, Donald W; Colombo, Robert

2011-11-01

A variety of contaminants have been detected in aquatic and terrestrial environments around the Paducah Gaseous Diffusion Plant (PGDP), Kentucky. The presence of these contaminants at the PGDP may pose a risk to biota, yet little is known about the bioaccumulation of contaminants and associated effects in wildlife, especially in aquatic turtles. The current study was initiated to evaluate: (1) the accumulation of heavy metals (Cd, Cr, Cu, Pb, and Hg) in aquatic ecosystems associated with the PGDP using red-eared slider turtle (Trachemys scripta elegans) as biomonitors; (2) maternal transfer of heavy metals; and (3) potential hematological and immunological effects resulting from metal accumulation. A total of 26 turtles were collected from 7 ponds located south, adjacent, and north of the PGDP. Liver Cu concentrations were significantly different among ponds and Cu concentrations in eggs were positively correlated with female Cu concentrations in kidney. The concentrations of heavy metals measured in turtle tissues and eggs were low and, based on previous studies of reptiles and established avian threshold levels of heavy metals, did not appear to have adverse effects on aquatic turtles inhabiting ponds near the PGDP. However, total white blood cell counts, heterophil to lymphocyte ratio, and phytohemagglutinin stimulation index were correlated with metal concentrations. Because other factors may affect the hematological and immunological indices, further investigation is needed to determine if these effects are associated with metal exposure, other contaminants, or disease.

Bulk-plasmon contribution to the work function of metals

International Nuclear Information System (INIS)

Gutierrez, F A; DIaz-Valdes, J; Jouin, H

2007-01-01

By consideration of the Koopmans theorem expression for the work function of a metal, we find that the total height of the surface barrier potential equals the value of the bulk-plasmon energy of pure metals. As a consequence a simple formula for the work function is obtained which shows better agreement with the experimental data than the most complete existent theories

Bioavailability of Sediment-bound Heavy Metals on the East African ...

African Journals Online (AJOL)

The results revealed that heavy metal levels at some locations were higher than at others. Cd, Mn and Co were more concentrated in labile fractions compared to the other elements. These metals are easily liberated into overlying water, making them available for biological uptake. More than 62% of the total concentrations ...

A preclinical numerical assessment of a polyetheretherketone femoral component in total knee arthroplasty during gait

NARCIS (Netherlands)

Ruiter, L. de; Janssen, D.W.; Briscoe, A.; Verdonschot, N.J.

2017-01-01

BACKGROUND: Conventional total knee replacement designs show high success rates but in the long term, the stiff metal components may affect bone quality of the distal femur. In this study we introduce an all-polymer total knee replacement device containing a PEEK femoral component on an UHMWPE

The possibilities of magnetic resonance imaging in the diagnostics of complications after metal-on-metal hip arthroplasty

Directory of Open Access Journals (Sweden)

A. A. Vergay

2013-01-01

Full Text Available Objective: to find adverse periprosthetic local tissue reactions after metal-on-metal hip arthroplasty with ASR XL heads. Material and methods: 119 patients with 134 ASR XL head - Corail prostheses were treated in 2007-2009. The results were studied in 94 cases (105 prostheses - 84%. Average follow-up time consisted 62 ± 3 months. MRI was performed in 12 patients (13 hips who had clinical nonsatisfaction. Obtained data were compared with 21 MRI (24 hips of controlled group with good and perfect clinical results. Results. We found variations of normal periprosthetic tissue condition. Adverse reactions were identified in 10 cases. To improve the quality of pictures we developed special MRI adjustments and regimes of work. Conclusion: MRI diagnostics is indicated for the patients with metal-on-metal total hip arthroplasty in order to identify adverse local tissue reactions. The improvement of picture quality needs special adjustment of MRI equipment.

Direct in Situ Conversion of Metals into Metal-Organic Frameworks: A Strategy for the Rapid Growth of MOF Films on Metal Substrates.

Science.gov (United States)

Ji, Hoon; Hwang, Sunhyun; Kim, Keonmok; Kim, CheolGi; Jeong, Nak Cheon

2016-11-30

The fabrication of metal-organic framework (MOF) films on conducting substrates has demonstrated great potential in applications such as electronic conduction and sensing. For these applications, direct contact of the film to the conducting substrate without a self-assembled monolayer (SAM) is a desired step that must be achieved prior to the use of MOF films. In this report, we propose an in situ strategy for the rapid one-step conversion of Cu metal into HKUST-1 films on conducting Cu substrates. The Cu substrate acts both as a conducting substrate and a source of Cu 2+ ions during the synthesis of HKUST-1. This synthesis is possible because of the simultaneous reaction of an oxidizing agent and a deprotonating agent, in which the former agent dissolves the metal substrate to form Cu 2+ ions while the latter agent deprotonates the ligand. Using this strategy, the HKUST-1 film could not only be rapidly synthesized within 5 min but also be directly attached to the Cu substrate. Based on microscopic studies, we propose a plausible mechanism for the growth reaction. Furthermore, we show the versatility of this in situ conversion methodology, applying it to ZIF-8, which comprises Zn 2+ ions and imidazole-based ligands. Using an I 2 -filled HKUST-1 film, we further demonstrate that the direct contact of the MOF film to the conducting substrate makes the material more suitable for use as a sensor or electronic conductor.

A preliminary categorization of end-of-life electrical and electronic equipment as secondary metal resources

International Nuclear Information System (INIS)

Oguchi, Masahiro; Murakami, Shinsuke; Sakanakura, Hirofumi; Kida, Akiko; Kameya, Takashi

2011-01-01

Highlights: → End-of-life electrical and electronic equipment (EEE) as secondary metal resources. → The content and the total amount of metals in specific equipment are both important. → We categorized 21 EEE types from contents and total amounts of various metals. → Important equipment types as secondary resources were listed for each metal kind. → Collectability and possible collection systems of various EEE types were discussed. - Abstract: End-of-life electrical and electronic equipment (EEE) has recently received attention as a secondary source of metals. This study examined characteristics of end-of-life EEE as secondary metal resources to consider efficient collection and metal recovery systems according to the specific metals and types of EEE. We constructed an analogy between natural resource development and metal recovery from end-of-life EEE and found that metal content and total annual amount of metal contained in each type of end-of-life EEE should be considered in secondary resource development, as well as the collectability of the end-of-life products. We then categorized 21 EEE types into five groups and discussed their potential as secondary metal resources. Refrigerators, washing machines, air conditioners, and CRT TVs were evaluated as the most important sources of common metals, and personal computers, mobile phones, and video games were evaluated as the most important sources of precious metals. Several types of small digital equipment were also identified as important sources of precious metals; however, mid-size information and communication technology (ICT) equipment (e.g., printers and fax machines) and audio/video equipment were shown to be more important as a source of a variety of less common metals. The physical collectability of each type of EEE was roughly characterized by unit size and number of end-of-life products generated annually. Current collection systems in Japan were examined and potentially appropriate collection

Occupational Metallic Mercury Poisoning in Gilders

Directory of Open Access Journals (Sweden)

M Vahabzadeh

2016-04-01

Full Text Available Occupational exposure to elemental mercury vapor usually occurs through inhalation during its utilizations. This leads to a variety of adverse health effects. In some Islamic cities, this type of poisoning may occur during gilding of shrines using elemental mercury with gold. Herein, we report on three male patients aged 20–53 years, who were diagnosed with occupational metallic mercury poisoning due to gilding of a shrine. All patients presented with neuro-psychiatric disorders such as anxiety, loss of memory and concentration, and sleep disorders with high urinary mercury concentrations of 326–760 μg/L upon referring, 3–10 days after cessation of elemental mercury exposure. Following chelating therapy, the patients recovered clinically and their mercury concentrations declined to non-toxic level (<25 μg/L. Health, environmental and labor authorities, as well as the gilders should be aware of the toxicity risk of exposure to metalic mercury during gilding in closed environments and act accordingly.

"Rocking-Chair"-Type Metal Hybrid Supercapacitors.

Science.gov (United States)

Yoo, Hyun Deog; Han, Sang-Don; Bayliss, Ryan D; Gewirth, Andrew A; Genorio, Bostjan; Rajput, Nav Nidhi; Persson, Kristin A; Burrell, Anthony K; Cabana, Jordi

2016-11-16

Hybrid supercapacitors that follow a "rocking-chair"-type mechanism were developed by coupling divalent metal and activated carbon electrodes in nonaqueous electrolytes. Conventional supercapacitors require a large amount of electrolyte to provide a sufficient quantity of ions to the electrodes, due to their Daniell-type mechanism that depletes the ions from the electrolyte while charging. The alternative "rocking-chair"-type mechanism effectively enhances the energy density of supercapacitors by minimizing the necessary amount of electrolyte, because the ion is replenished from the metal anode while it is adsorbed to the cathode. Newly developed nonaqueous electrolytes for Mg and Zn electrochemistry, based on bis(trifluoromethylsulfonyl)imide (TFSI) salts, made the metal hybrid supercapacitors possible by enabling reversible deposition on the metal anodes and reversible adsorption on an activated carbon cathode. Factoring in gains through the cell design, the energy density of the metal hybrid supercapacitors is projected to be a factor of 7 higher than conventional devices thanks to both the "rocking-chair"-type mechanism that minimizes total electrolyte volume and the use of metal anodes, which have substantial merits in capacity and voltage. Self-discharge was also substantially alleviated compared to conventional supercapacitors. This concept offers a route to build supercapacitors that meet dual criteria of power and energy densities with a simple cell design.

Total reflection x-ray analysis of metals in blood samples

International Nuclear Information System (INIS)

Nakamura, Takuya; Matsui, Hiroshi; Kawamata, Masaya

2009-01-01

The sample preparation for TXRF (total reflection X-ray fluorescence) quantitative analysis of trace elements in human blood samples was investigated. In the TXRF analysis, a solution sample is dropped and dried on a flat substrate, and then the dried residue is measured. In this case, the dried residue should be flat not to disturb X-ray total reflection on the substrate. In addition, it is required to simply measure the whole blood sample by TXRF method, although a serum is analyzed in many cases. Thus, we studied the optimum conditions of the sample preparation of the whole blood by adding the pure water to apply Hemolysis phenomenon, where blood cells are destroyed due to different of the osmotic pressure, leading to flat residue. It was found that the best S/B ratio was obtained when the whole blood was diluted 8 times with pure water. Moreover, it was investigated the influence of the surface chemical condition of the glass substrate on the shape of the dried reside of the blood sample. When the surface of the glass substrate was hydrophilic, the shape of the dried residues was not uniform, as a result, the quantitative data of TXRF analysis gave a large deviation. On the other hand, when the surface of the glass was hydrophobic, the shape of the residue was almost uniform, as a result, a good reproducibility was obtained. Another problem was an outer ring of the dried residue of the blood. This uneven ring absorbs the primary X-rays, caused to low determined quantitative data. Thus, we tried the heating way of the dropped blood sample at a high temperature of 200 degrees. In this case, the blood sample was dried immediately, and a flat homogeneous dried residue was obtained without the outer ring. Using the optimized conditions for sample preparation, human blood sample was quantitatively measured by TXRF and ICP-AES. A good agreement was obtained in TXRF and ICP-AES determinations; however, the measurement of Cl and Br will be an advantage of TXRF, because

A complementary and synergistic effect of Fe-Zn binary metal oxide in the process of high-temperature fuel gas desulfurization

Institute of Scientific and Technical Information of China (English)

翁斯灏; 吴幼青

1996-01-01

57Fe Mossbauer spectroscopy was used to investigate the evolution of Fe-Zn binary metal oxide sorbent in the process of high-temperature fuel gas desulfurization. The results of phase analyses show that Fe-Zn binary metal oxide sorbent is rapidly reduced in hot fuel gas and decomposed to new phases of highly dispersed microcrystalline elemental iron and zinc oxide, both of which become the active desulfurization constituents. A complementary and synergistic effect between active iron acting as a high sulfur capacity constituent and active zinc oxide acting as a deep refining desulfurization constituent exists in this type of sorbent for hot fuel gas desulfurization.

Applications of Metals for Bone Regeneration

Directory of Open Access Journals (Sweden)

Kristina Glenske

2018-03-01

Full Text Available The regeneration of bone tissue is the main purpose of most therapies in dental medicine. For bone regeneration, calcium phosphate (CaP-based substitute materials based on natural (allo- and xenografts and synthetic origins (alloplastic materials are applied for guiding the regeneration processes. The optimal bone substitute has to act as a substrate for bone ingrowth into a defect, as well as resorb in the time frame needed for complete regeneration up to the condition of restitution ad integrum. In this context, the modes of action of CaP-based substitute materials have been frequently investigated, where it has been shown that such materials strongly influence regenerative processes such as osteoblast growth or differentiation and also osteoclastic resorption due to different physicochemical properties of the materials. However, the material characteristics needed for the required ratio between new bone tissue formation and material degradation has not been found, until now. The addition of different substances such as collagen or growth factors and also of different cell types has already been tested but did not allow for sufficient or prompt application. Moreover, metals or metal ions are used differently as a basis or as supplement for different materials in the field of bone regeneration. Moreover, it has already been shown that different metal ions are integral components of bone tissue, playing functional roles in the physiological cellular environment as well as in the course of bone healing. The present review focuses on frequently used metals as integral parts of materials designed for bone regeneration, with the aim to provide an overview of currently existing knowledge about the effects of metals in the field of bone regeneration.

When double-wall carbon nanotubes can become metallic or semiconducting

International Nuclear Information System (INIS)

Moradian, Rostam; Azadi, Sam; Refii-tabar, Hashem

2007-01-01

The electronic properties of double-wall carbon nanotubes (DWCNTs) are investigated via density functional theory. The DWCNTs are separated into four categories wherein the inner-outer nanotubes are metal-metal, metal-semiconductor, semiconductor-metal and semiconductor-semiconductor single-wall nanotubes. The band structure of the DWCNTs, the local density of states of the inner and outer nanotubes, and the total density of states are calculated. We found that for the metal-metal DWCNTs, the inner and outer nanotubes remain metallic for different distances between the walls, while for the metal-semiconductor DWCNTs, decreasing the distance between the walls leads to a phase transition in which both nanotubes become metallic. In the case of semiconductor-metal DWCNTs, it is found that at some distance the inner wall becomes metallic, while the outer wall becomes a semiconductor, and if the distance is decreased, both walls become metallic. Finally, in the semiconductor-semiconductor DWCNTs, if the two walls are far from each other, then the whole DWCNT and both walls remain semiconducting. By decreasing the wall distance, first the inner, and then the outer, nanotube becomes metallic

Stopping power of degenerate electron liquid at metallic densities

International Nuclear Information System (INIS)

Tanaka, Shigenori; Ichimaru, Setsuo

1985-01-01

We calculate the stopping power of the degenerate electron liquid at metallic densities in the dielectric formalism. The strong Coulomb-coupling effects beyond the random-phase approximation are taken into account through the static and dynamic local-field corrections. It is shown that those strong-coupling and dynamic effects act to enhance the stopping power substantially in the low-velocity regime, leading to an improved agreement with experimental data. (author)

Penile strangulation by iron metal ring: A novel and effective method of management

Science.gov (United States)

Paonam, Somorendro; Kshetrimayum, Nillachandra; Rana, Indrajit

2017-01-01

Penile strangulation by metal ring is a rare urological emergency situation which requires urgent decompression of the penis to avoid adverse effect. It is usually associated with an attempt to improve sexual act and/or to prolong erection. But sometimes, cutting of the ring to decompress the penis safely is a very difficult task particularly when the strangulating object is a hard metal object as in our case. Here, we present a case which was managed by cutting in a novel way with the help of dental micromotor with wheel shape bur. PMID:28216935

Penile strangulation by iron metal ring: A novel and effective method of management

Directory of Open Access Journals (Sweden)

Somorendro Paonam

2017-01-01

Full Text Available Penile strangulation by metal ring is a rare urological emergency situation which requires urgent decompression of the penis to avoid adverse effect. It is usually associated with an attempt to improve sexual act and/or to prolong erection. But sometimes, cutting of the ring to decompress the penis safely is a very difficult task particularly when the strangulating object is a hard metal object as in our case. Here, we present a case which was managed by cutting in a novel way with the help of dental micromotor with wheel shape bur.

Metal artifact reduction image reconstruction algorithm for CT of implanted metal orthopedic devices: a work in progress

International Nuclear Information System (INIS)

Liu, Patrick T.; Pavlicek, William P.; Peter, Mary B.; Roberts, Catherine C.; Paden, Robert G.; Spangehl, Mark J.

2009-01-01

Despite recent advances in CT technology, metal orthopedic implants continue to cause significant artifacts on many CT exams, often obscuring diagnostic information. We performed this prospective study to evaluate the effectiveness of an experimental metal artifact reduction (MAR) image reconstruction program for CT. We examined image quality on CT exams performed in patients with hip arthroplasties as well as other types of implanted metal orthopedic devices. The exam raw data were reconstructed using two different methods, the standard filtered backprojection (FBP) program and the MAR program. Images were evaluated for quality of the metal-cement-bone interfaces, trabeculae ≤1 cm from the metal, trabeculae 5 cm apart from the metal, streak artifact, and overall soft tissue detail. The Wilcoxon Rank Sum test was used to compare the image scores from the large and small prostheses. Interobserver agreement was calculated. When all patients were grouped together, the MAR images showed mild to moderate improvement over the FBP images. However, when the cases were divided by implant size, the MAR images consistently received higher image quality scores than the FBP images for large metal implants (total hip prostheses). For small metal implants (screws, plates, staples), conversely, the MAR images received lower image quality scores than the FBP images due to blurring artifact. The difference of image scores for the large and small implants was significant (p=0.002). Interobserver agreement was found to be high for all measures of image quality (k>0.9). The experimental MAR reconstruction algorithm significantly improved CT image quality for patients with large metal implants. However, the MAR algorithm introduced blurring artifact that reduced image quality with small metal implants. (orig.)

Fernald scrap metal and recycling and beneficial reuse

International Nuclear Information System (INIS)

Motl, G.P.

1993-01-01

The Fernald plant, formerly known as the Feed Materials Production Facility, is located on a 1050-acre site 17 miles northwest of downtown Cincinnati, Ohio. Site construction was initiated in 1951 to fabricate uranium metal to meet defense production requirements of the U.S. Department of Energy (DOE). In October 1990, the DOE transferred management responsibility for the site from its Defense Programs organization to the Office of Environmental Restoration and Waste Management. In August 1991, the site was renamed the Fernald Environmental Management Project (FEMP) to reflect the site's new cleanup mission. During 40 yr of plant operation, a scrap metal storage area grew to contain 5000 t of scrap metal. Material in the pile, such as structural steel, crushed drums, tanks, and pipes, is contaminated with uranium to levels up to 200,000 disintegrations per minute alpha. In July 1991, cleanup of this pile was designated a CERCLA removal action under the Comprehensive Environmental Response, Compensation, and Liability Act and a consent agreement executed between the DOE and the U.S. Environmental Protection Agency

COATING OF POLYMERIC SUBSTRATE CATALYSTS ON METALLIC SURFACES

Directory of Open Access Journals (Sweden)

H. HOSSEINI

2010-12-01

Full Text Available This article presents results of a study on coating of a polymeric substrate ca-talyst on metallic surface. Stability of coating on metallic surfaces is a proper specification. Sol-gel technology was used to synthesize adhesion promoters of polysilane compounds that act as a mediator. The intermediate layer was coated by synthesized sulfonated polystyrene-divinylbenzene as a catalyst for production of MTBE in catalytic distillation process. Swelling of catalyst and its separation from the metal surface was improved by i increasing the quantity of divinylbenzene in the resin’s production process and ii applying adhesion pro¬moters based on the sol-gel process. The rate of ethyl silicate hydrolysis was intensified by increasing the concentration of utilized acid while the conden¬sation polymerization was enhanced in the presence of OH–. Sol was formed at pH 2, while the pH should be 8 for the formation of gel. By setting the ratio of the initial concentrations of water to ethyl silicate to 8, the gel formation time was minimized.

Method of producing homogeneous mixed metal oxides and metal-metal oxide mixtures

International Nuclear Information System (INIS)

Quinby, T.C.

1980-01-01

A method for preparing particulate metal or metal oxide of controlled partile size comprises contacting an an aqueous solution containing dissolved metal values with excess urea at a temperature sufficient to cause urea to react with water to provide a molten urea solution containing the metal values; heating the molten urea solution to cause the metal values to precipitate, forming a mixture containing precipitated metal values; heating the mixture containing precipitated metal values to evaporate volatile material leaving a dry powder containing said metal values. The dry powder can be calcined to provide particulate metal oxide or reduced to provide particulate metal. Oxide mixtures are provided when the aqueous solution contains values of more than one metal. Homogeneousmetal-metal oxide mistures for preparing cermets can be prepared by selectively reducing at least one of the metal oxides. (auth)

Volume variation of Gruneisen parameters of fcc transition metals

Indian Academy of Sciences (India)

Unknown

average discrepancy between the values of γ measured by various methods for 23 metals. Experimentally only the total Gruneisen parameter can be measured. The total. Gruneisen parameter is the sum of lattice, electronic and probably magnetic contribution. The letter term is present in palladium (White and Pawlok 1970) ...

Atomic Act amended

International Nuclear Information System (INIS)

Drabova, D.

2002-01-01

In the paper by the chairwoman of the Czech nuclear regulatory authority, the history of Czech nuclear legislation is outlined, the reasons for the amendment of the Atomic Act (Act No. 18/1997) are explained, and the amendments themselves are highlighted. The Act No. 13/2002 of 18 December 2001 is reproduced from the official Collection of Acts of the Czech Republic in the facsimile form. The following acts were thereby amended: Atomic Act No. 18/1997, Metrology Act No. 505/1990, Public Health Protection Act No. 258/2000, and Act No. 2/1969 on the Establishment of Ministries and Other Governmental Agencies of the Czech Republic. (P.A.)

Heavy metal concentrations in plants and different harvestable parts: A soil-plant equilibrium model

International Nuclear Information System (INIS)

Guala, Sebastian D.; Vega, Flora A.; Covelo, Emma F.

2010-01-01

A mathematical interaction model, validated by experimental results, was developed to modeling the metal uptake by plants and induced growth decrease, by knowing metal in soils. The model relates the dynamics of the uptake of metals from soil to plants. Also, two types of relationships are tested: total and available metal content. The model successfully fitted the experimental data and made it possible to predict the threshold values of total mortality with a satisfactory approach. Data are taken from soils treated with Cd and Ni for ryegrass (Lolium perenne, L.) and oats (Avena sativa L.), respectively. Concentrations are measured in the aboveground biomass of plants. In the latter case, the concentration of metals in different parts of the plants (tillering, shooting and earing) is also modeled. At low concentrations, the effects of metals are moderate, and the dynamics appear to be linear. However, increasing concentrations show nonlinear behaviors. - The model proposed in this study makes possible to characterize the nonlinear behavior of the soil-plant interaction with metal pollution.

Heavy metal concentrations in plants and different harvestable parts: A soil-plant equilibrium model

Energy Technology Data Exchange (ETDEWEB)

Guala, Sebastian D. [Instituto de Ciencias, Universidad Nacional de General Sarmiento, Gutierrez 1150, Los Polvorines, Buenos Aires (Argentina); Vega, Flora A. [Departamento de Bioloxia Vexetal e Ciencia do Solo, Facultade de Bioloxia, Universidade de Vigo, Lagoas, Marcosende, 36310 Vigo, Pontevedra (Spain); Covelo, Emma F., E-mail: emmaf@uvigo.e [Departamento de Bioloxia Vexetal e Ciencia do Solo, Facultade de Bioloxia, Universidade de Vigo, Lagoas, Marcosende, 36310 Vigo, Pontevedra (Spain)

2010-08-15

A mathematical interaction model, validated by experimental results, was developed to modeling the metal uptake by plants and induced growth decrease, by knowing metal in soils. The model relates the dynamics of the uptake of metals from soil to plants. Also, two types of relationships are tested: total and available metal content. The model successfully fitted the experimental data and made it possible to predict the threshold values of total mortality with a satisfactory approach. Data are taken from soils treated with Cd and Ni for ryegrass (Lolium perenne, L.) and oats (Avena sativa L.), respectively. Concentrations are measured in the aboveground biomass of plants. In the latter case, the concentration of metals in different parts of the plants (tillering, shooting and earing) is also modeled. At low concentrations, the effects of metals are moderate, and the dynamics appear to be linear. However, increasing concentrations show nonlinear behaviors. - The model proposed in this study makes possible to characterize the nonlinear behavior of the soil-plant interaction with metal pollution.

Heavy metals in the volcanic environment and thyroid cancer.

Science.gov (United States)

Vigneri, R; Malandrino, P; Gianì, F; Russo, M; Vigneri, P

2017-12-05

In the last two decades thyroid cancer incidence has increased worldwide more than any other cancer. Overdiagnosis of subclinical microcarcinomas has certainly contributed to this increase but many evidences indicate that a true increase, possibly due to environmental factors, has also occurred. Thyroid cancer incidence is markedly increased in volcanic areas. Thus, the volcanic environment is a good model to investigate the possible factors favoring thyroid cancer. In the volcanic area of Mt. Etna in Sicily, as well as in other volcanic areas, a non-anthropogenic pollution with heavy metals has been documented, a consequence of gas, ash and lava emission. Soil, water and atmosphere contamination, via the food chain, biocontaminate the residents as documented by high levels in the urines and the scalp hair compared to individuals living in adjacent non-volcanic areas. Trace amounts of metals are essential nutrients but, at higher concentrations, can be toxic for living cells. Metals can behave both as endocrine disruptors, perturbing the hormonal system, and as carcinogens, promoting malignant transformation. Similarly to other carcinogens, the transforming effect of heavy metals is higher in developing organisms as the fetus (contaminated via the mother) and individuals in early childhood. In the last decades environment metal pollution has greatly increased in industrialized countries. Although still within the "normal" limits for each single metal the hormesis effect (heavy metal activity at very low concentration because of biphasic, non linear cell response) and the possible potentiation effect resulting from the mixture of different metals acting synergistically can explain cell damage at very low concentrations. The effect of metals on the human thyroid is poorly studied: for some heavy metals no data are available. The scarce studies that have been performed mainly focus on metal effect as thyroid endocrine disruptors. The metal concentration in tissues has

Alternative materials to improve total hip replacement tribology.

Science.gov (United States)

Santavirta, Seppo; Böhler, Max; Harris, William H; Konttinen, Yrjö T; Lappalainen, Reijo; Muratoglu, Orhun; Rieker, Claude; Salzer, Martin

2003-08-01

An improvement in tribology of bearing surfaces is an effective means of increasing the longevity of total hip replacement (THR). Currently, 3 approaches are available to achieve this aim: first, use of highly cross-linked UHMWPE; second, aluminum oxide ceramic bearings, and third, metal-on-metal bearings. Cross-linking reduces the wear resistance of UHMWPE markedly without impairment of other significant properties of the material. Simulator studies and some clinical long-term (10-22 years) follow-up surveys suggest an almost immeasurable wear of the highly cross-linked UHMWPE-based acetabular components during an expected clinical life span. Bioinert alumina ceramic (aluminum oxide) was introduced 3 decades ago for THR-bearing surfaces to improve performance and longevity. Alumina ceramic is entirely biostable and bioinert and has good mechanical properties. For correctly positioned alumina-on-alumina bearings, the annual linear wear rate has been reported to be 3.9 microm. Alumina heads have been successfully used in combination with polyethylene sockets, but as regards wear, the best results have been obtained with alumina-on-alumina bearings. In ceramic THR bearings, precise manufacture and contact surface geometry, including optimal clearance, are most important. For the currently available products, the component fracture risk is almost nonexistent (less than 1 per 1000). Metal-on-metal bearings were used in the early stage of THR surgery, although not all old designs were successful. More recent analyses of the early series have shown the advantages of metal-on-metal to be better and have led to a renaissance of this articulation. Initially, stainless steel was used because it was easy to manufacture and polish. Current metal-on-metal bearings are based on cobalt-chromium-molybdenum alloys with varying carbon contents. Such bearings are self-polishing. Linear wear rates remain at the level of a few microm a year. An improvement in technology has increased

Bioaccumulation of eight heavy metals in cave animals from Dashui ...

African Journals Online (AJOL)

ajl2

karst caves and water systems in the caves are well developed. So, heavy metals can contaminate cave envi- ronment and affect cave animals. Karst topography is widely distributed in Guizhou province, China, accounting for 73.8% of the total land area. So, the examination of heavy metal pollution in cave soil and water ...

Assessment of nutrients and metals in sediments of Ogba river ...

African Journals Online (AJOL)

Total organic carbon (TOC) and nitrate (NO3--N) were negatively correlated with sand but positively related to clay (P<0.01). No significant relationship was found between metals except for Ni and cadmium (Cd), and Fe and Ni. In addition, no significant relationship was found between TOC and metals (Fe, Zn, Cu, Cd, ...

A unified picture of the crystal structures of metals

Science.gov (United States)

Söderlind, Per; Eriksson, Olle; Johansson, Börje; Wills, J. M.; Boring, A. M.

1995-04-01

THE crystal structures of the light actinides have intrigued physicists and chemists for several decades1. Simple metals and transition metals have close-packed, high-symmetry structures, such as body-centred cubic, face-centred cubic and hexagonal close packing. In contrast, the structures of the light actinides are very loosely packed and of low symmetry-tetragonal, orthorhombic and monoclinic. To understand these differences, we have performed total-energy calculations, as a function of volume, for both high-and low-symmetry structures of a simple metal (aluminium), a non-magnetic transition metal (niobium), a ferromagnetic transition metal (iron) and a light actinide (uranium). We find that the crystal structure of all of these metals is determined by the balance between electrostatic (Madelung) interactions, which favour high symmetry, and a Peierls distortion of the crystal lattice, which favours low symmetry. We show that simple metals and transition metals can adopt low-symmetry structures on expansion of the lattice; and we predict that, conversely, the light actinides will undergo transitions to structures of higher symmetry on compression.

A unified picture of the crystal structures of metals

International Nuclear Information System (INIS)

Soederlind, P.; Eriksson, O.; Johansson, B.; Wills, J.M.; Boring, A.M.

1995-01-01

The crystal structures of the light actinides have intrigued physicists and chemists for several decades. Simple metals and transition metals have close-packed, high-symmetry structures, such as body-centred cubic, face-centred cubic hexagonal close packing. In contrast, the structures of the light actinides are very loosely packed and of low symmetry -tetragonal, orthorhombic and monoclinic. To understand these differences, we have have performed total-energy calculations, as a function of volume, for both high- and low-symmetry structures of a simple metal (aluminium), a non-magnetic transition metal (niobium), a ferromagnetic transition metal (iron) and a light actinide (uranium). We find that the crystal structure of all these metals is determined by the balance between electrostatic (Madelung) interactions, which favour high symmetry, and a Peierls distortion of the crystal lattice, which favours low symmetry. We show that simple metals and transition metals can adopt low-symmetry structures on expansion of the lattice; and we predict that, conversely, the light actinides will undergo transitions to structures of higher symmetry on compression. (author)

75 FR 63703 - Privacy Act of 1974; Privacy Act Regulation

Science.gov (United States)

2010-10-18

... FEDERAL RESERVE SYSTEM 12 CFR Part 261a [Docket No. R-1313] Privacy Act of 1974; Privacy Act... implementing the Privacy Act of 1974 (Privacy Act). The primary changes concern the waiver of copying fees... records under the Privacy Act; the amendment of special procedures for the release of medical records to...

Privacy Act

Science.gov (United States)

Learn about the Privacy Act of 1974, the Electronic Government Act of 2002, the Federal Information Security Management Act, and other information about the Environmental Protection Agency maintains its records.

HEAVY METALS CONTAMINATION OF TOPSOIL AND ...

African Journals Online (AJOL)

a

emissions from automobile exhaust, waste incineration, land disposal of wastes, use of .... of total organic carbon increased from 2.0 ± 1.5 % in the top soil to 3.42 ± 0.83 ..... Thus, accumulation of heavy metals in the soil has potential to restrict.

Tribology of total hip arthroplasty prostheses: What an orthopaedic surgeon should know.

Science.gov (United States)

Rieker, Claude B

2016-02-01

Articulating components should minimise the generation of wear particles in order to optimize long-term survival of the prosthesis.A good understanding of tribological properties helps the orthopaedic surgeon to choose the most suitable bearing for each individual patient.Conventional and highly cross-linked polyethylene articulating either with metal or ceramic, ceramic-on-ceramic and metal-on-metal are the most commonly used bearing combinations.All combinations of bearing surface have their advantages and disadvantages. An appraisal of the individual patient's objectives should be part of the assessment of the best bearing surface. Cite this article: Rieker CB. Tribology of total hip arthroplasty prostheses: what an orthopaedic surgeon should know. EFORT Open Rev 2016;1:52-57. DOI: 10.1302/2058-5241.1.000004.

Pathogens and Heavy Metals Concentration in Green Leafy Vegetables

Directory of Open Access Journals (Sweden)

Abida Begum

2010-01-01

Full Text Available Presence of heavy metal and bacterial pathogen in randomly collected samples of green leafy from various stations of Bengaluru city was detected. Heavy metals (cadmium, zinc, copper, iron, chromium, nickel and lead were analyzed by tri-acid digestion method. The presence of heavy metals in general was in the order of Cd>Zn>Cu>Fe>Cr>Pb. Trace metal concentration in all green leafy vegetables of stations 1-5 were within permissible limit and it has been exceeded in station 6-10. This indicated high levels of soil contamination pose potential danger for the vegetables grown in the vicinity of Arakere lake, Bannerghatta road, Gottigere lake, Naganaikanakere, Bommasandra lake, Hulimavu lake, Kelaginakere and Amblipura lake. The total bacteria and coliforms were enumerated on TSA (Tryptone Soya Agar and VRBA (Violet Red Bile Agar media respectively. The total bacterial count in randomly collected samples of coriander ranged from 296 cfu/g to 8 cfu/g, in palak from 16 cfu/g to 0.9 cfu/g, whereas in case of cabbage was 104 cfu/g to 0.9 cfu/g which is an indication of improper pre-harvest and post harvest handling.

Method of producing homogeneous mixed metal oxides and metal--metal oxide mixtures

International Nuclear Information System (INIS)

Quinby, T.C.

1978-01-01

Metal powders, metal oxide powders, and mixtures thereof of controlled particle size are provided by reacting an aqueous solution containing dissolved metal values with excess urea. Upon heating, urea reacts with water from the solution to leave a molten urea solution containing the metal values. The molten urea solution is heated to above about 180 0 C, whereupon metal values precipitate homogeneously as a powder. The powder is reduced to metal or calcined to form oxide particles. One or more metal oxides in a mixture can be selectively reduced to produce metal particles or a mixture of metal and metal oxide particles